Thermal-Hydraulic Phenomena - November 28, 2001

                 Official Transcript of Proceedings


Title:                    Advisory Committee on Reactor Safeguards
                               Thermal-Hydraulic Phenomena Subcommittee

Docket Number:  (not applicable)

Location:                 Rockville, Maryland

Date:                     Wednesday, November 28, 2001

Work Order No.: NRC-116                               Pages 1-369

                   NEAL R. GROSS AND CO., INC.
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                          (202) 234-4433                         UNITED STATES OF AMERICA
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                             NOVEMBER 28, 2001
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                            ROCKVILLE, MARYLAND
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                 The Subcommittee met at the Nuclear Regulatory
           Commission, Two White Flint North, T2B1, 11545
           Rockville Pike, at 8:30 a.m., Graham B. Wallis, 
           Chairman, presiding.
                 GRAHAM B. WALLIS, Chairman
                 THOMAS S. KRESS
                 F. PETER FORD
                 GRAHAM M. LEITCH
                 WILLIAM J. SHACK
                 VIRGIL L. SCHROCK
                 PAUL A. BOEHNERT, Staff
                 RICHARD LOBEL, Staff           ALSO PRESENT:
           STEVE BAJOREK
           HARV HANNEMAN
           ROBERT HENRY
           JOSEPH M. KELLY
           NORM LAUBEN
           JOHN MAHAFTY
           MIKE TESTA
           JENNIFER L. UHLE
           TOM ULLSES
           WEIDONG WANG
           Introduction . . . . . . . . . . . . . . . . . . . 4
           NRC RES Presentation:
                 T/H Phenomena Research Program . . . . . . . 4
                 Assessment & Quantification
                       Steve Bajorek. . . . . . . . . . . . 155
                 Status of Experimental Programs
                       Steve Bajorek. . . . . . . . . . . . 183
           Realistic Analyses of Large Dry Containment Response
           to DBA Using EPRI MAAP Code
                 Robert Henry . . . . . . . . . . . . . . . 252
                 Mike Testa, Beaver Valley. . . . . . . . . 253
                 Harv Hanneman, Point Beach . . . . . . . . 258
           NRR Presentation
           Comment on Realistic Model Approach
                 Richard Lobel. . . . . . . . . . . . . . . 361
           Adjourn. . . . . . . . . . . . . . . . . . . . . 369
                                                    (8:32 a.m.)
                       CHAIRMAN WALLIS:  This is a meeting of the
           ACRS Subcommittee on Thermal-Hydraulic Phenomena.  I
           am Graham Wallis, the Chairman of the Subcommittee.
                       Other ACRS members in attendance are Peter
           Ford, Thomas Kress, Graham Leitch and William Shack.
                       ACRS consultant in attendance is Virgil
                       The purpose of this meeting is for the
           Subcommittee, firstly, to continue review of the NRC
           Office of Nuclear Regulatory Research Activities
           pertaining to thermal-hydraulic phenomena in support
           of the ACRS annual report for the Commission on the
           NRC Safety Research Program.
                       And secondly, discuss a proposal by the
           licensees of the Point Beach and Beaver Valley plant
           to perform more realistic analysis of the containment
           design basis accident EPRI/MAAP code.
                       The Subcommittee will gather information,
           analyze relevant issues and facts and formulate
           proposed positions and actions as appropriate for
           deliberation by the full committee.  
                       Paul Boehnert is the cognizant ACRS staff
           engineer for this meeting.
                       The rules for participation in today's
           meeting have been announced as part of the notice of
           this meeting previously published in the Federal
           Register, November 15, 2001.
                       Portions of the meeting will be closed to
           the public as necessary to discuss information
           considered proprietary to the electric power concerns. 
           A transcript of this meeting will be kept.  And the
           open portions of this transcript will be made
           available, as stated in the Federal Register notice.
                       It is requested that speakers first
           identify themselves and speak with sufficient clarity
           and volume so that they can be readily heard.
                       We have received no written comments or
           requests for time to make oral statements from the
                       Now, our hope as a Subcommittee is that
           today's meeting will be the highlight of the year as
           we hear about all this great work which is going on. 
            I call upon Jack Rosenthal to get us started.
                       MR. ROSENTHAL:  Thank you.  I'm Jack
           Rosenthal. I'm the branch chief of the Safety Margins
           and Systems Analysis branch in the Office of Research,
           and I just have some introductory remarks and then, as
           you can see from your agenda, Jennifer will talk about
           applications, Jennifer Uhle.  And then Joe Kelly about
           code consolidation and Steve Bajorek about our
           experimental program, and I'll get help from much of
           the other staff.
                       But I wanted to make some introductory
           remarks in a few areas.  The easiest one is that we've
           accumulated a fair amount of hardware now, and so at
           least the capability to run the codes.  And we're
           proud of a new PC cluster that we're doing in CFDR.
                       The next thing, more important, and I
           don't want to embarrass my staff, but we have now in
           fact I think a world premier staff of people that have
           come on board, and several recent ones.
                       Joe Kelly was at the NRC and has returned.
                       Steve Bajorek was at Westinghouse in
           Kansas State and is now with us.
                       Joe Staudenmeier and Tony Ullses were in
           NRR and have joined us.
                       Chris Murray was at Penn State and has
           joined us.
                       And so we have a staff that's now capable
           of analyzing experiments, developing the codes and
           doing the safety analysis.  And we should be proud of
           the staff.
                       In terms of products, okay, we are using
           our codes to make regulatory decisions.  We're using
           MELCOR to come up with a source term for 50.44,
           combustible gas control.
                       We're using RELAP and TRAC to modify 50.46
                       There was another subcommittee out of OSU,
           and you heard that we're using RELAP and CFD and REMIX
           to do PTS.
                       We're using RELAP SCDAP to do steam
           generator high temperature severe accident work, and
           you had a separate briefing on that.
                       We did some work on combined injected rod
           LOCA as part of the CRDM issues, and we used RELAP and
           PARCS and for AP1000 we'll be using RELAP and TRAC. 
           For our work on synergy we're going to be using TRAC
           and PARCS.  
                       So we're actually using these codes to
           make regulatory decisions, and that's very healthy. 
           And much of that work is being done in-house, and
           that's very healthy.
                       The last point that I wanted to make is
           that in prior years it was typical to have a vendor
           come in with some calculations and what we would cause
           our contractors to do some calculations to check
           vendor calculations.  But the regulatory decision, to
           a great extent, was based on what the vendor came in
           with.  But for changing the rules, we're looking at
           this synergy issue or the objective art issue.  These
           are safety issues that are before us.  And we're using
           our analysis to make those regulatory decisions.  We
           don't have a vendor to balance this stuff off against,
           except in the AP1000 case.  And that puts a greater
           burden on us.
                       The entire Office of Research is paying
           far greater attention to QA than it did in the past,
           because we're using this for regulatory decisions and
           we're trying to do the code development and
           configuration management, etcetera, to modern
           standards in support of those regulatory decisions.
                       It's the first time that somebody gave me
           a microphone.  I didn't realize I talked softly.
                       With that short introduction, I'd like to
           turn it over to Jennifer for about an hour -- Jennifer
           Uhle who is the assistant branch chief now in our
                       MS. UHLE:  We're going to do something a
           little different.  Usually we talk about the status of
           our code development efforts and then talk a little
           bit about applications.  But I think you guys are
           tired of hearing it in that order, so today I'm going
           to start off with what we're currently using our tools
           for.  The question gets asked what do you use the
           codes for; they're, of course, time-consuming to
           develop and we have an invested effort in that.  And
           so we're going to be answering this question for you,
                       So I'm just going to talk a little bit
           about the branch mission, the current uses of the
           codes at NRC.  You know, the current applications we
           have for licensee submittals, generic issues, risk-
           informing regulation, design certification.  And we
           just draw the conclusion that you'll find on the
           summary side now, and that is that you do utilize the
           codes, they are used at NRC for field application. 
           And it is our goal to continue to improve this
           analytical capability to respond to these emerging
                       We always discuss about the consolidation
           effort.  That effort, of course, sometimes gets in
           trouble for the fact that we are not making
           improvements to the physics as quickly as some people
           may want.  And I just want to focus or make the
           statement that we are consolidating first, we are
           making improvements as we need to respond to these
           applications as they arise.  But by the end of 2002
           we'll be in a prime position to have one code.  At
           that point in time we'll really focus on improving the
           physical models and as well as the very detailed
           developmental assessment.  And Joe Kelly and Steve
           Bajorek will be discussing that further.
                       I'm going to skip over this, because I'll
           do that on the summary side, but Jack Rosenthal had
           pointed out that we do have five recent hires that
           have really added to the capability of the branch, and
           you'll be hearing from them.
                       MEMBER LEITCH:  Jennifer, maybe it's
           obvious, but I'm not sure I understand.  What is the
           advantage of a consolidated code?
                       MS. UHLE:  We used to have four thermal-
           hydraulic codes.  And we used RELAP for PWR small
           break loss of coolant accidents and transients.  We
           used the TRAC-B code for large break loss of coolant
           accidents for PWRs.  We used the TRAC-B code for BWR
           applications that only required one 1-D kinetics.  And
           then we used the Ramona code for places that required
           3-D kinetics capabilities.  And because of that each
           of these codes have very similar features.  They're
           not that different, and so we had a lot of maintenance
           points; that wasn't an efficient way to operate. It
           was more costly than it needed to be.  So when we
           needed to make improvements we, in a sense, had to do
           it four times over.  So improvements weren't made as
                       Additionally, the user base was
           distributed across these four codes.  So, again,
           instead of moving forward we were sort of moving in
           parallel and not making improvements as fast as we
           would have liked.
                       Additionally, each of the codes had a
           different input deck.  And so when you're looking at
           maintaining these large input decks, these very
           complex models, you would have to do it for two
           different inputs, because the PWRs would use RELAP and
           TRAC, the BWRs would use Ramona and TRAC-B.  So it
           just wasn't an efficient way to proceed, especially
           with the budget reductions and the fact that we wanted
           to bring the technology in-house and have in-house
           staff to develop and maintain and use the codes for
           the regulatory applications.
                       So that was the decision to go with the
           consolidated code.  And what we did is we selected
           TRAC-B as the base of that consolidation, and we
           modernized it so it's a new architecture.  It's very
           easy to modify, very easy to extend to other
           applications and to couple to other tools like a CFD
           code.  We haven't done that yet, but this is where
           we're heading.
                       And what we've done is we've just taken
           the features that were in the different codes, all of
           the four different codes, and we've only taken the
           different things that the other codes could do and
           brought them into TRAC-B.  We now call it TRAC-M
           because it's modernized, and we're trying to find a
           name for the code.  It's a very sore subject.
                       MEMBER LEITCH:  And this will be
           consolidating code that NRC --
                       MS. UHLE:  Yes. Yes. It's in-house
           expertise.  We work with contractors.  Gil Actess is
           in the back of the room.  He's at ISL, Information
           System Laboratories.  John Mahafty is Penn State
           University.  He was an original developer of TRAC-B at
           Los Alamos.  He's at Penn State now.  He is our
           numerics guru.  And Tom Downar at Purdue University is
           working on -- is more of the original developer of the
           PARCS code.  Now we don't use the code as stand-alone
           in PARCS; we've coupled just the kinetics routines to
           TRAC.  So it's a modular, so it's the PARCS modular. 
           But, again, we work alongside of the contractors, the
           staff does, and we've really developed in-house
           expertise.  Tony Ullses is now starting to do PARCS
           development so that we can rely more on in-house staff
           and rely on contractors for specialized skills, so
           it's not part of the staffing plan to have a full-time
           employee on one of those particular skills.
                       MEMBER LEITCH:  Now, when I think of the
           consolidated code, I think in terms of simplicity and
           efficiency.  That raises sort of the feeling that
           maybe there's some compromise of precision for the
           individual codes, a specific code for Bs and Ps and
           small break. large break and so forth.  Is any of that
           precision compromised?
                       MS. UHLE:  That was a concern.  I think
           Dr. Shack is of that mind.  I think that Dr. Zuberg
           was of that mind as well.  And the bottom line is we
           just couldn't continue to operate that way.  We
           couldn't make any more improvements to the codes
           because we were spending all of our resources on
           maintenance.  And so as these issues were identified,
           we just didn't have the staff or the budget to be able
           to make the changes.  So in a perfect world maybe that
           would be the best way to go, if you had infinite
           resources and infinite time.
                       So the consolidation plan is that we are
           forming the consolidation activities.  We can read all
           of the input decks from all the other codes, so we've
           recovered the input decks.  And at this point or
           shortly we'll be starting the developmental assessment
           phase. And for the targeted applications of each of
           the predecessor codes, we will be comparing the
           results of the modernized code to the other codes to
           make sure that we're as good as the other codes for
           those applications.
                       And the way that the architecture is set
           up, it's really the physical models; wall drag,
           interfacial drag, interfacial heat transfer, et
           cetera.  Those are the points that made the codes
           different.  And, for instance, the solution of setting
           up the numerics, solving the matrix, performing input
           processing, performing or exporting the answer to a
           graphical tool; those are all common things.  So
           really the only big differences between the codes is
           the physical models.  The architecture of the
           modernized code is allowing us to do component-
           specific physical models. 
                       If I'm a pipe, I'm going to use this
           interfacial drag, this wall drag.  If I'm a channel
           component in a BWR; okay, now I have a rod bundle
           there, the interfacial drag is going to be different
           than it would be in a pipe of the same hydraulic
           diameter.  So because of the architecture it's set up
           to very easily incorporate component specific physical
           models which will allow us to be as good, and then
           eventually better than the old codes.  So we're
           accommodating that concern.
                       We have to prove that to you, but that is
           our goal.
                       CHAIRMAN WALLIS:  Of course, you're also
           checking that this pipe really is a pipe and isn't a
           pump because --
                       MS. UHLE:  Yes, of course.  
                       John wanted to say something.  John
                       MR. MAHAFTY:  This is John Mahafty.
                       I'd just like to make a comment.  I've
           been kicking around with computers since they took up
           the whole room and they had the kind of computer power
           you have in your watch right now, and I understand the
           concerns about efficiency from that kind of ancient
           perspective.  But the fact is now memory on computers
           is massive and it's cheap.  Disk space on computers is
           massive and cheap.  So that it doesn't matter to me if
           I've got a large code with a bunch of special
           subroutines for interfacial guide and BWR and another
           set for interfacial drag and PWR core; if I'm running
           BWR, that stuff never gets swapped in where the action
           is, which is your real local memory on your chip.  It
           sits out somewhere and gets swapped into virtual
           memory.  It's not impacting you from the standpoint of
           the efficiency of operation of the code, but it's
           there when you need it and it's tied together with all
           these things that everybody needs to make the
           maintenance and the improvement of the package
           important.  And things don't get overlooked as much.
                       Now I can remember the old days.  It used
           to drive me nuts.  We'd find some problem with TRAC-E
           and we knew that it was an important issue that the
           people in BWR side, maybe we only had five of them
           looking at it and communicating that and getting all
           of this information to run off, it would sometimes
           take years.  But now it's in one place and there are
           people thinking about it as a whole, so you don't lose
           improvements that are applicable to everything, and
           it's a big advantage.
                       MR. ROSENTHAL:  Let me do a follow-up
           then, if I may.  And, John, you're absolutely right. 
           Every time we turn around, of course, it's a tenth of
           what it did before for more horsepower, computer
           horsepower.  But people are expensive, and it takes
           over a staff-year to create an input deck, one of
           these really big input decks.  And so you really gain
           some efficiencies by being able to use decks that were
           previously created or have common decks for purposes,
                       So I think we're really going to achieve
           some efficiencies.
                       MS. UHLE:  I just want to add to the idea
           of taking a year to develop a plant deck, and that was
           again in Jack's old time frame, in the olden times, in
           the time of the dinosaur.  That's how long it used to
                       I'll be doing a bit of a presentation on
           the graphical user interface, which we've also
           recognized the inefficiency associated with plant
           modeling and feel we have a program to handle that.
           We've demonstrated that before to the ACRS, but I'll
           be touching on some of those points that I think bring
           that to light, that we have improved the efficiency of
           the plant modeling.
                       MEMBER SHACK:  Just out of curiosity. 
           What language have you settled on?  I mean, these were
           originally --
                       MS. UHLE:  Fortran 90.
                       MEMBER SHACK:  Fortran 90.
                       CHAIRMAN WALLIS:  Well, the plant modeling
           involves people looking at a lot of drawings and then
           turning this into computerese.  I would think with a
           new plant and the plant is already a computer model
           before it's even being built and you don't have that
           problem; having to look at drawings and figure out
           where the pipes go and  --
                       MS. UHLE:  You're assuming that we
           communicate to the licensee.
                       CHAIRMAN WALLIS:  Well, if that's the
           problem, you need to fix it.
                       MS. UHLE:  At this point that is something
           that we have thought about, being able to scan in
           something from the architectural engineers.  
                       CHAIRMAN WALLIS:  That's the way that
           industry does it.
                       MS. UHLE:  Right.  Right.  Well, they
           don't build an input deck by scanning in the graphics
                       CHAIRMAN WALLIS:  But in the automobile
           industry, if they want to get a piece from a supplier,
           they just send them a computer model of the stuff that
           they need to know and they've got it.
                       MS. UHLE:  But the computer model's not
           going to have lost coefficients, reverse and forward
           lost coefficients. I mean they're going to have
           geometry, and that's what we can recover.  
                       CHAIRMAN WALLIS:  So you have to figure
           that out.
                       MS. UHLE:  But the rest of it is going to
           still require somebody knowing the code, knowing what
           each of the input is required.
                       Well, I mean we have talked about that as
           an ideal way to go, being able to recover any of the
           geometric information.  
                       CHAIRMAN WALLIS:  Right.
                       MS. UHLE:  We have talked about that.
                       MEMBER SHACK:  They probably don't have
           computerized geometric models in most of these plants.
                       MS. UHLE:  They'll have like tech -- what
           is it called -- CAD drawings.  They'll have CAD
           drawings.  And so we've thought about being able to
           take in the data from the CAD drawings and getting the
           geometry.  And that is somewhere we want to head,
           we're not there yet.  And of course, at NRC we don't
           have CAD drawings, so it would require interface with
           the industry.
                       I want to talk to you about the mission of
           the branch, to give you an idea that this is the
           Safety Margins and Systems Analysis Branch.  So we are
           tasked with the idea of maintaining these analytical
           tools.  We're also tasked with maintaining the
           infrastructure for the understanding of the
           phenomenology to help out NRR on more complex issues. 
           And this is applied to severe accidents as well as the
           thermal-hydraulics, and as well as the field behavior. 
           What you're hearing from us today is the thermal-
           hydraulics, but we are hoping to follow suit in the
           severe-accident and field-behavior areas so that the
           team can seamlessly interact throughout the branch;
           and that includes coupling the computer tools, the
           field behavior code to the thermal-hydraulics code,
           the severe accident code to the thermal-hydraulics
           code, and bringing in-house expertise.  And so it's an
           exciting time in the branch.
                       Hopefully, if all the good things you hear
           today, you can think that's going to be applying to
           severe accident.  And if it's something you don't
           like, well then tell us so we don't make the same
           mistake twice.
                       MEMBER KRESS:  When you say criticality
           safety, what all is wrapped up in that?
                       MS. UHLE:  Criticality safety originally--
           well, for instance in the dry cask PRA they have asked
           the branch --
                       MEMBER KRESS:   Okay.  You're not just
           limiting this to reactors then?
                       MS. UHLE:  No.  No.  For instance, the
           most --
                       MR. ROSENTHAL:  The burn-up credit comes
           from in our branch analytically and we provide, as a
           user need --
                       MEMBER KRESS:  I understand what you mean.
                       MS. UHLE:  Tony Ullses, in the back of the
           room, is currently running some calcs with the dry
           cask PRA to just double check that there's, obviously,
           very -- I don't know what the word is -- low, low, low
           probability that anything could happen and cause a
           criticality accident.  And so he's doing that in the
           branch, because we have the reactor physics tools. 
           We've coupled the reactor with some kinetics tools,
           but we're getting the reactor physics and with that
           there is quantum PYLAR codes for criticality.
                       MEMBER FORD:  You mentioned safety margins
           on this slide.  Is there any plans in the future to
           incorporate, for instance, aging phenomena for
           construction materials?
                       MS. UHLE:  We are going to talk -- I will
           actually talk a little bit about that with respect to
           the power uprate synergy program that we're undergoing
           at this point.  And Joe Staudenmeir is the lead on
           that.  But, additionally, we do interact with the
           engineering division, well for instance, through the
           pressurized thermal shock rule we are looking at risk
           informing the PTS rule in the way that we're giving
           them thermal-hydraulic information and then they're
           putting it into their FAVA code for the fracture
                       So the whole office, really, I think it's
           a nice tie and we're all starting to interact a bit
           more.  There's a lot of cross-division, cross-branch,
           as well as in the branch cross-section interaction.
                       MEMBER FORD:  Forgive me, because I'm new
           to this organization.  Is this a new mission or has
           this been a mission you've had for ten years?
                       MS. UHLE:  I think this is a mission that
           we've always had, but I think the way NRC is currently
           operating we're trying to do it in a more efficient,
           more --
                       CHAIRMAN WALLIS:  Integrated.
                       MS. UHLE:  Yes, integrated and more of a
           outcome-oriented, and all these management buzzwords
           that make you sick.  But, you know, looking at the
           user offices as our customers, looking at the fact
           that we're supporting the PRA work as our customers.
           And because of that, I think this has helped as far as
           people understanding who is doing what and who to go
           to talk instead of not knowing and calling their
           professor or, you know, and not knowing what NCR is
           currently doing.
                       CHAIRMAN WALLIS:  It also helps if your
           customer is really listening and is in on that
           decision making.
                       MS. UHLE:  Oh, yes, right, and that goes
           to the user need process.
                       Okay.  So we're getting into the activity,
           because now I'm talking about power uprates synergy. 
           So you read my mind here.
                       This was actually I think at one point
           discussed by the ACRS, the full committee, looking at
           the potential for synergy.  Synergy coming from the
           fact that we're operating with higher burnups, higher
           power and plant aging.  And we are currently looking
           at license amendments for BWRs up to 20 percent power
                       Also the Office of Research -- I don't
           want to be giving you a full review of this program
           because I'm not the lead on this program, but I just
           want to talk about our branch's use of the codes to
           support this program.
                       We've got an independent study we'll be
           doing; the best most rigorous method we could do would
           be a level 3 PRA before and after the results, but we
           don't have the time or the staffing, or the funding to
           do that.  So we're trying to do this in an efficient
           way, so due to the time and funding limitations we're
           going to focus on components and the scenarios of high
           risk significance, and using the knowledge that we
           have in the field to point to the things that are most
           sensitive to the changes.  We're looking at the
           results of NUREG-1150 as a guide.  And we're going to
           be looking at generic safety issues and reviewing them
           to see that if there was something that is affected by
           any of these changes within the operations.
                       MEMBER KRESS:  Now let me see if I
           understand that.  You will do a level 3, but for just
           selective sequences?
                       MS. UHLE:  Yes.
                       MEMBER KRESS:  And those sequences will be
           the ones you feel are more important?
                       MS. UHLE:  Yes.
                       MEMBER KRESS:  And you'll pick out a
           number of plants to do this with?
                       MR. ROSENTHAL:  The level 3 would include
           consequence analysis.
                       MS. UHLE:  Right.
                       MEMBER KRESS:  Yes, you'll forget about
           LERF and go to the full consequence.
                       MS. UHLE:  Well, we're looking at
           consequence on the synergy program after listening to
           the advice from Joe Staudenmeier.
                       CHAIRMAN WALLIS:  So you're going to look
           at casualties in the surrounding countryside and
           things like that?  I mean is that part of your
                       MS. UHLE:  Yes, I mean it's going to
           result in a source term and then --
                       MEMBER KRESS:  Well, before we get carried
           away, I think I'd like to lend the Subcommittee's
           support to your doing that.  Because LERF can only do
           it when you are talking about power upgrades. 
                       MS. UHLE:  Well, I mean, the focus is
           looking at the source term.
                       MEMBER KRESS:  Yes, absolutely.  
                       MS. UHLE:  And we are going out to source
                       MEMBER KRESS:  And we really ought to do
           the level 3 in this case rather than stop at LERF.
                       MS. UHLE:  And if we have source term
           going to, you know, the health effects, I mean that's
           -- I don't see how that's a big step.
                       MEMBER KRESS:  Will you use specific sites
           for this or some sort of a --
                       MS. UHLE:  Joe, do you want to stand up
           and talk?  Joe Staudenmeier is the lead on this.  I
           mean, maybe a lot of it could just be my
           misunderstanding, but I mean if we're doing source
           term, I don't see why we wouldn't do the final health
           effect.  I mean, that's just a matter of running the
           Max code, which takes 5 seconds.  But maybe I'm
           offering work that the office isn't willing to do.  I
           don't know.
                       MEMBER KRESS:  Stick by it, I hope you do. 
           Go ahead.
                       MR. STAUDENMEIER:  Joe Staudenmeier.
                       Tentatively we had planned to do
           consequence analysis.  We don't really have all the
           details of this whole study all worked out yet, but
           tentatively we'll look at the consequence analysis
           with the PRA people.  We're going to provide guidance
           based on NUREG-1150 study on what sort of sequences we
           should be looking at and also engineering is providing
           information on materials and things like that.
                       MEMBER KRESS:  Okay.
                       MR. STAUDENMEIER:   It's hopefully going
           to be an integrated study that gives consequence
           numbers, or at least what we think may be resulting
           consequence numbers being more like a prioritization
           analysis rather than a full level analysis.
                       MEMBER KRESS:  Would you use the SPAR
           models for this or --
                       MR. STAUDENMEIER:  I don't know the
           details of what GRA would be
                       MEMBER KRESS:  All right.
                       MEMBER FORD:  Could you  -- and you ought
           to be able to put the government timing and funding
           limitations off.  In light of, for instance, synergism
           between higher power flux and plant aging from a
           physics point of view, there's a lot of things which
           are not understood in a quantitative sense.   So there
           is a lot to do beforehand. So far as timing and
           funding limitations would you have these for is it 3
           years? -- 
                       MS. UHLE:  I think we have funding out for
           another 3 years.  Is that right, Joe?  Three years?
                       MR. STAUDENMEIER:  Yes, the program is
           scheduled to go over three years.   The total
           contracting money for the first two years, I think, is
           about $800,000, and from last year about $1500.
                       CHAIRMAN WALLIS:  So probably three years
           most of these BWRs will already have had power
           operation approved?
                       MS. UHLE:  That's coming out of NRR.  What
           we're doing is an independent analysis.
                       CHAIRMAN WALLIS:  I know, but it's so
           interesting.  So your report will come out after the
           fact and then --
                       MR. STAUDENMEIER:  We are working on a
           confirmatory report and we are not going to concern
           ourselves with the licensing process.  Unless we do
           find something.  If we do find something it will
           affect licensing, obviously, we'll provide that
                       MEMBER KRESS:  Better late than never.
                       MEMBER SCHROCK:  So the BWR presentations,
           these upgrades claimed that the bundle power is not
           increased, and the flux therefore is not increased. 
           So you have a situation in which the total power in a
           system is increased by --
                       MS. UHLE:  Right.
                       MEMBER SCHROCK:  -- working the bundle so
           they're both hanging over the mark.  But it doesn't
           come through clearly to me how you're dealing with the
           increased total power, I mean in the context of source
           term and things of this sort.  You don't have a higher
           local power density, and so the onset of failures is
           not changed in the sense of local conditions, but the
           amount of the core that's involved in the onset of
           failures is increased.
                       MS. UHLE:  Right.
                       MEMBER SCHROCK:  How is that --
                       MS. UHLE:  Affecting source term?
                       MEMBER SCHROCK:  Yes.
                       MS. UHLE:  Well, I mean with the higher
           power the higher fission productivity and then of
           course if you're getting --
                       MEMBER SCHROCK:  Well, of course.  But the
           issue is how much of it gets out.
                       MS. UHLE:  Right.  Right.
                       MEMBER SCHROCK:  And how does the failure
                       MS. UHLE:  Right.  But if we're looking at
           on the very unlikely situation where you'd have a core
           melt, then you know it's going to be the average of
           the core that's determining the source term, not just
           the hot bundle.
                       MEMBER SCHROCK:  Yes --
                       MEMBER KRESS:  You would get more out
                       MEMBER SCHROCK:  Oh, I'm sure you'd get
           more out, but my question is how it's being determined
           in these new evaluations.
                       MEMBER KRESS:  Well, it depends on how
           they nodalize the core.
                       MEMBER SCHROCK:  Because as I read the
           stuff that we received, I was reading there's an
           increase in flux, there's an increase in temperature,
           there's an increase in this and that, which we heard
           in the arguments in favor of the uprates it didn't
           exist because we don't have an increase in bundle
           power, we don't have an increase in center line
           temperature of the fuel, we don't have this, we don't
           have that.  Whereas, the description that I read
           sounds to me like it's contrary to the claims that
           were made in the evidence supporting the approval of
           these 20 percent uprates.
                       MS. UHLE:  I think Joe wants to make a
           statement here.  
                       MEMBER SCHROCK:  
                       MS. UHLE:  He's behind you.
                       MR. STAUDENMEIER:  The source of the core-
           melt progression in source term release is something
           we're going to be evaluating under this program.  We
           plan on planning some severe accident calculations. 
           I think we'll probably be talking in more detail about
           this program, coming up with a presentation sometime,
           I imagine being the first half of next year coming
           down to explain what the parts of our program are and
           schedule a presentation just describing this in more
           detail.  Right now Jennifer has a long way to go, and
           this may not be a good time to discuss it any further.
                       CHAIRMAN WALLIS:  She has a long way to go
           in terms of the slides she's going to cover.  You're
           going to cover 19 or 20 or so?
                       MS. UHLE:  Well, I don't know. I'm 
                       Along those lines, though, I just want to
           point out that we will be using the codes in the
           branches, the severe accident analyses with melt core,
           talking about the melt progression and then the
           thermal-hydraulic codes.  And so we'll be focusing on
           the risk-significant events and the risk-significant
           components providing input as success criteria,
           operator action times, stating the case of ATWS, and
           also different component failure modes.
                       If it`s a DET the division of engineering
           to look at the effect of additional hydraulic loads on
           the components, crunch the numbers and come out with
           a new risk value.
                       So I'll skip the next one there, because
           I think we've talked about that.
                       One thing I want to talk about, though, is
           the fact that we're using this code and how can you be
           assured that we are getting an okay answer for, say,
           the BWR cases.  The next stage in the consolidation is
           very consistent with the fact that we need to do a
           developmental assessment.  And so what we're going to
           do is that we are focusing on the BWR models first. 
           We'll be looking at them in the consolidation matrix,
           the DA matrix, the BWR models.  And that's, of course,
           good timing with respect to the BWR synergy.  So we
           will be running a developmental assessment for BWRs
           with the code, and we'll be using the TRAC code for
                       We are currently involved in the Peach
           Bottom Turbine Trap using the TRAC-M code in the PARCS
           3-D kinetics module.  And Tony Ullses -- he's in the
           back of the room -- he is the lead on that.
                       Based on the results, and I have a few
           results for you to show you, we found that we know
           we're going to have to do some BWR specific physical
           models.  And what was put in was an interfacial drag
           model was changed and -- I think it was the two phase
           loss multiplier for -- I'm sorry, the two phase
           multiplier for the wall drag that was important in the
           BWR sense.
                       Once we replaced those models and reran
           the Peach Bottom Turbine Trip for just the CHAN, you
           know the BWR channel component in the core, we got
           very good answers.  We're still looking at it again to
           focus on what models we need to change to improve
           those answers.  And I just want to --
                       CHAIRMAN WALLIS:  If you take the RELAP
           models and put them in TRAC, do you predict the same
           answers as RELAP predicted?
                       MS. UHLE:  If we were to do that, it would
           take time to do it.  We haven't done that.  But in
           general -- in general you would say yes.
                       CHAIRMAN WALLIS:  You would expect --
                       MS. UHLE:  If we run in the semi-implicit
           numeric scheme.
                       CHAIRMAN WALLIS:  It's a test that we
           probably should run, isn't it, so that there isn't
           something peculiar about TRAC which gives different
           answers from RELAP with the same models?
                       MS. UHLE:  Well, that's where the
           developmental assessment work will --
                       CHAIRMAN WALLIS:  You haven't done that
                       MS. UHLE:  That's what the next stage is.
                       CHAIRMAN WALLIS:  I mean, it's related in
           a way to Graham's question; when you consolidate these
           codes, the question will arise probably about whether
           or not you're recapturing what the codes could do
                       MS. UHLE:  Right.  Right.  And so that's
           why the next phase of consolidation is the most
           important phase.
                       CHAIRMAN WALLIS:  So you won't really find
           out if there's a hitch to consolidation until you get
           to that point?
                       MS. UHLE:  You have no faith.
                       MEMBER SCHROCK:  I've expressed concern
           for years about using interfacial drag as a tuning
           device in the codes.  And what can you say about what
           you're doing now that's any different than what's been
           done before?  In terms of the physics, isn't it
           necessary to have a clearer explanation as to why you
           needed a different model --
                       MS. UHLE:  Yes, we do.
                       MEMBER SCHROCK:  -- for one reactor as
           compared to the other?
                       MS. UHLE:  Yes.  In particular the CHAN
           component.  The CHAN component is essentially a pipe. 
           And if you put in your hydraulic diameter --
                       MEMBER SCHROCK:  That`s in the code, but
           in the reactors they're rod bundles.
                       MS. UHLE:  I know.  Right.  Exactly.  So
           currently in the code, in the TRAC-M code, if you're
           going to have a CHAN component, it is a pipe with a
           different hydraulic diameter.  So your interfacial
           drag is going to be much -- you know, calculated to be
           very high.  Because in reality you have this channel
           there -- sorry.  You have this rod bundle there and
           you know with the same hydraulic diameter you have a
           much lower interfacial drag.  So in that particular
           instance we have to put in an interfacial drag model
           that reflects the fact that there is a rod bundle in
           this pipe.  That's physically based.
                       MEMBER SCHROCK:  Well, I didn't, I guess,
           fully understand the argument.
                       In both reactor systems you have rod
           bundles.  You do have pipes.  And so now you're --
                       MS. UHLE:  In the PWR we have a 3-D
           hydraulic model, so it's not a pipe because the
           hydraulic is three-dimensional -- you can have cross
           flow, what have you, you don't have the channel boxes.
                       MEMBER SCHROCK:  Well, there's a scheme
           for accounting for cross flow.  Calling it three-
           dimensional is a stretch.
                       MS. UHLE:  Not in the TRAC code.  It's a
           three-dimensional model, three-dimensional hydraulic
                       MEMBER KRESS:  They don't use these little
                       MS. UHLE:  We don't use the cross flow
                       I think Joe Kelly wants to say a few
           words, maybe clear it up.
                       MR. KELLY:  This is Joe Kelly, from
           research.  And I think I can clear that up, Professor
                       In TRAC-P, its mission was for large break
           LOCA.  So consequently, interfacial drag in the core
           for normal, you know, bubbly flow was never considered
           a priority.  They were always worried about reflux,
           first of all, from boiling etcetera.  So the models
           that were developed for that actually were fairly
           crude, based on bubbles and slugs where the slug size
           is limited by the hydraulic diameter of the channel. 
           But, as you know, in an actual LOCA configuration the
           vapor structures actually span a number of
           subchannels, and it can lead to much higher slip than
           you would get if you only took into account the
           hydraulic diameter of a rod bundle.
                       So, because the modeling TRAC-P is
           relatively crude, it was in fact never extensively
           accessed against rod bundle void fracture data. 
           There's no expectation that it would do a good job. 
           And what we've found is, yes, indeed it does not do a
           very good job when you apply it to BWR operating
           conditions.  And so we needed to implement a model,
           and what we chose was the one from TRAC-B that
           actually does try to model the interfacial drag in a
           rod bundle.  And that's what was done for Beach Bottom
           Turbine Trip, and I'll talk a little more about that.
                       MEMBER SCHROCK:  Okay.
                       CHAIRMAN WALLIS:  When we review other
           codes, we've been reviewing other codes over the past
           few years, we get a stack of stuff like this, you
           know, the documentation.  All the equations are
           spelled out, justified, and the verifications are
           explained.  Are we going to get that for your code?
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  When do we get that?
                       MS. UHLE:  End of 2002.
                       CHAIRMAN WALLIS:  That's a long way.
                       MS. UHLE:  Well, we won't know what
           physical models we're putting in the code until the
           end of 2002, when we've done the developmental
           assessment to make sure.
                       CHAIRMAN WALLIS:  Well, do you have a
           draft --
                       MS. UHLE:  We have a theory manual for
                       CHAIRMAN WALLIS:  If you had a draft
           version of the theory manual or something, we might
           give you some useful input before end of 2002.  And if
           we're going to raise any problems --
                       MS. UHLE:  Are you offering?
                       CHAIRMAN WALLIS:  -- the sooner we do it,
           the better.
                       MS. UHLE:  So you're offering to be a
                       CHAIRMAN WALLIS:  Well, it just turns out
           that in a peculiar way we should never fault the ACRS. 
           We act as sometimes reviewers of these codes and we
           find what look like -- not what I should call errors,
           but --
                       MS. UHLE:  Right. We have a theory manual
           for the base TRAC-P code.  We can provide that to you
           as well as --
                       CHAIRMAN WALLIS:  It might be useful if we
           saw that before you think you've got the final
                       MS. UHLE:  Right.  I'll report that back,
           although my management is here now.
                       CHAIRMAN WALLIS:  Because that would be
           really embarrassing if we found an error in some
           fundamental thing after you think it's final.
                       MEMBER SCHROCK:  We used to complain about
           the lack of recommendation on TRAC.  And I remember at
           a meeting in Saratoga Springs -- from Las Alamos I
           guess.  Said that the latest version was fully
           documented and I said "Well, I've never seen it."  And
           so there was some correspondence between he and four
                       I think that he's under the impression
           that it's been reviewed by the ACRS.  I don't think it
           ever appeared at the ACRS.
                       MS. UHLE:  Okay.  Well, I mean that would
           be very helpful to us if you're willing to do that.
                       CHAIRMAN WALLIS:  But you're going to
           write your own documentation for these facts, right? 
           you're not just going to pick some original TRAC
           document --
                       MS. UHLE:  We're going to redo what needs
           to be redone, yes.
                       CHAIRMAN WALLIS:  Right.
                       MS. UHLE:  Sure.  As our developmental
           work has been proceeding, we have quality assurance
           guidelines and we've generated more documentation than
           you can imagine.
                       CHAIRMAN WALLIS:  If you go back to the
           very original TRAC documentation, such as it was, it
           was extraordinary.  It was extraordinary, and it was
           a maze trying to figure out what was happening.
                       MS. UHLE:  I think of "extraordinary" as
                       CHAIRMAN WALLIS:  Oh, no, no.  It was
           extraordinary.  I'll try to choose a word that's
                       MR. ROSENTHAL:  Let me just chime in.  I
           think what's going to happen, the goal and reality
           would be that by the time we're done, this code will
           have more review and more scrutiny than anything else
           out there with a large user community, both
           domestically and internationally.  And we share source
           code as well as compiled code.  And we put it to the
           user community so that it will be far better reviewed
           and understood than I think the commercial code.
                       CHAIRMAN WALLIS:  I was just trying to --
           and you might think about how the ACRS could be most
           helpful to you in that process.  We don't have the
           time to read every line and all that, but as you know
           we do look at selected parts of this code
           documentation and assure ourselves that it's credible.
                       MS. UHLE:  And I guess you're interested
           in the momentum equation?
                       CHAIRMAN WALLIS:  We want to be helpful. 
           The last thing we want to do is to shoot you down in
           some way.
                       MS. UHLE:  Yes.  I think the --
                       CHAIRMAN WALLIS:  And the last time you
           want to do it is at the end of the process.
                       MS. UHLE:  Yes, I mean if you're willing
           to do that, it would be great.  I would think that we
           would be accepting that.
                       CHAIRMAN WALLIS:  Why don't you think
           about how we might be helpful there.
                       MS. UHLE:  I'm not important enough to
           make that decision.  It's these other people.
                       MR. ROSENTHAL:  Sure you are.  Sure you
                       MS. UHLE:  You have the results here, I
           think, in your slides. I'll just skip over them.  If
           you want to pursue them, because I think we're running
           out of time.
                       MEMBER LEITCH:  This Peach Bottom Turbine
           Trip, is that the generator breaker openings or how is
           this -- or does that make a difference?  In other
           words, we run them along in the turbine trips, is
                       MS. UHLE:   It was a task scheduled at the
           Peach Bottom facility.  Tony Ullses can elaborate on
           that; he's the lead, as well as Bajorek helped out
           originally.  Go ahead.
                       MR. ULLSES: It was actually a cycled test
           that they ran at the facility during coasting down
           gradually from 100 percent power. 
                       MEMBER LEITCH:  Okay.  From a 100 percent
           power?  You say they were coasting down?  They
                       MR. ULLSES:  Actually they were at low
           power and they -- they actually had multiple trips but
           they were down in the 60 percent power when they
           started the trip and they actually disabled the
           initial stops on the valve position --
                       MEMBER LEITCH:  Oh, I sure.  Okay.  So
           they closed the stop valves at 60 percent power. 
           Okay.  Thanks.
                       The other question I had related to that
           was you mentioned that in the previous LOCA, and I
           guess you didn't slide 5, but you referred to the
           Brown's Ferry ATWS.  I guess is that a full-blown
           ATWS, or is that the partial ATWS that occurred at
           Brown's Ferry in '76 or something?
                       MS. UHLE:  This is just on the matter from
           the BWR synergy.
                       MR. ULLSES:  That was a partial ATWS.
                       MR. KELLY:  Partial ATWS, yes.
                       MEMBER LEITCH:  So you're not using a
           full-blown ATWS for this reference here?
                       MR. KELLY:  Well, we're doing the plant
           calculations on a full-blown ATWS, but we're going to
           start with -- the deck was developed for the partial
           ATWS, which is what that was for, and there were some
           modern calculations on a former ATWS that we were
           evaluating and we're going to start off by rephrasing
           those calculations on TRAC-M using that deck as a
           surrogate high power BWR4 deck as a full ATWS.
                       MEMBER LEITCH:  Well, I guess I'm just a
           little confused as to why you would use the Brown's
           Ferry rather than a full-blown ATWS.
                       MR. KELLY:  Well, we are going to run a
           full-blown ATWS.  What Brown's Ferry had was a
           development responsible partial ATWS but there`s
           nothing in the input that would keep it running at a
           full ATWS.
                       MEMBER LEITCH:  Okay.  Okay.  Thank you.
                       MS. UHLE:  Okay.  I'm going to skip now to
           the MOX fuel issue.  I think we have talked about this
           before, but this is the idea of developing our
           kinetics capabilities to deal with MOX fuel.
                       The PARCS, the Purdue Advanced Reactor
           Core Simulator, that's the PARCS.  What we do is we
           coupled to just the kinetics features in the code.  So
           we use it as a module.  And we are improving the
           kinetics module to be able to handle MOX fuel.  We're
           adding the ability to do any number of energy groups
           because of the fact that plutonium has huge capture
           and fission resonances, and the beta is much lower
           than in uranium.  So you have to be much closer
           because -- you have to be much more accurate because
           you can be closer to prompt critical.
                       The way that the MOX core will be run is
           we will be, we think, be using eight groups for the
           MOX assemblies and two groups for the uranium
                       CHAIRMAN WALLIS:  These are delayed
           neutron group of the N?
                       MS. UHLE:  Yes, beta delayed neutron
                       CHAIRMAN WALLIS:  You only need two for U?
                       MS. UHLE:  I'm sorry?
                       CHAIRMAN WALLIS:  You only need two for U?
                       MS. UHLE:  Oh, sorry.  The groups.  No,
           these are two energy groups for --
                       CHAIRMAN WALLIS:  These are energy groups? 
           This is something else you're talking about?
                       MS. UHLE:  Well, N groups.  Additional
           energy groups.  N groups.
                       CHAIRMAN WALLIS:  I don't know what an N
           group is.
                       MS. UHLE:  That means N number of groups,
           how many groups.
                       CHAIRMAN WALLIS:  Well, group of what?
                       MS. UHLE:  How many bins of energy the
           neutrons can be in.
                       CHAIRMAN WALLIS:  I see.  I see.  Okay.
           Okay.  Thank you.
                       MS. UHLE:  Two fields of neutrons, like
           the vapor and the liquid.
                       CHAIRMAN WALLIS:  You have two groups
           there and eight groups here. 
                       MS. UHLE:  Yes.  I think Dr. Kress can
           help you on that.
                       CHAIRMAN WALLIS:  Well, it seemed funny,
           but I mean I guess this is a subgroup -- sub-sub
           title.  This is a sub of the title.  The neutron
           fraction isn't a subtitle of energy groups.  Okay. 
           Never mind.  
                       There are new problems with MOX, so we
           really can't be surprised.
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  New neutronic problems.
                       MS. UHLE:  I'm glad I got that across.
                       MEMBER SCHROCK:  Your bullet on reactivity
           difference due to mix of plutonium in the range is a
           little confusing.  Error in reactivity can be closer
           to prompt critical in MOX.
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  That's because of the
           delayed neutron fraction.
                       MEMBER SCHROCK:  You need a comma there
           somewhere?  Error in reactivity still can be closer.
                       MS. UHLE:  Can be closer to prompt
                       CHAIRMAN WALLIS:  Well, you worry about
           error because you don't have this cushion from the
           delayed neutron, isn't that the idea?
                       MS. UHLE:  Delayed neutrons.  So your
           prompt critical with --
                       MEMBER SCHROCK:  Well, I understand the
           problem, what I'm trying to understand is what message
           am I to get out of this statement.
                       MS. UHLE:  Okay.  Take a step back here.
                       Additional energy groups, there is a need
           to have additional energy groups, more than just two,
           that we currently use for uranium cores.  Okay?  
                       Why do we need additional energy groups?
           We need them because of the fact that plutonium has a
           lot of resonancy, and so around the epithermal range
           and at the 1 eV range, and around the -- in Pu-241 you
           get capture and fission resonances at the 1 eV to KeV
                       So you have these resonances, whereas in
           uranium you don't.  You pretty much can bend your
           energy groups of your neutrons into fast neutrons and
           thermal neutrons because there's none of these big
           resonances on the way scattering down to the thermal.
                       Additionally, you worry about error in
           reactivity.  We could have used the two energy groups
           and --
                       CHAIRMAN WALLIS:  Would you bend your
           betas?  The beta is an average of a whole lot of
           different betas, isn't it?
                       MS. UHLE:  It's an average of the betas.
                       CHAIRMAN WALLIS:  And do you have to worry
           about individual betas with plutonium?
                       MS. UHLE:  Yes.  In the 3-D -- yes.  In
           the code you do.  I took off the 235 beta and the --
                       CHAIRMAN WALLIS:  Well, that beta's just
           an average for you, isn't it?
                       MS. UHLE:  It's a beta for that isotope.
                       CHAIRMAN WALLIS:  There are different
           groups.  Right.  So there are different groups in the
           beta --
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  -- itself it subdivides. 
           Okay.  You didn't worry about that now, because you've
           got such a lower beta?
                       MS. UHLE:  Well, in the fission event
           you're -- I guess I don't understand what you're
           asking.  Do you understand what he's asking, Tony?
                       CHAIRMAN WALLIS:  There are separate
           groups.  I get confused about the groups.
                       MR. ULLSES:  Yes, the code itself, Dr.
           Wallis, it actually on a node-to-node basis will
           maintain an individual amount of the actual related
                       CHAIRMAN WALLIS:  But it looks at the
           simpler fractions of the separate groups?
                       MR. ULLSES:  Right.
                       CHAIRMAN WALLIS:  Okay.  
                       MS. UHLE:  Just to give you an idea that
           we have to be very accurate, more accurate than we do
           in uranium cores because of the fact that we are
           closer to prompt critical because of the --
                       CHAIRMAN WALLIS:  So it's not just the
           average, it's also the group which is slowest -- which
           is governing in a rapid transit, isn't it?  So it's
           not just the average you worry about?
                       MS. UHLE:  Well, it's the most dominant,
           the most dominant group.
                       CHAIRMAN WALLIS:  But, I guess Tony's got
           it all under control.  Tony's got it all under
           control, certainly.
                       MS. UHLE:  I'm sorry?
                       CHAIRMAN WALLIS:  I said Tony has it under
           control; that's all I'd really like to know.
                       MS. UHLE:  All right. Great. So does that
           explain this slide any better?
                       MEMBER SCHROCK:  Well, no.  The language
           is what I'm criticizing, as in that statement error in
           reactivity can be closer to --
                       MS. UHLE:  Okay.  Okay.
                       MEMBER SCHROCK:  There is a reactivity
           evaluation problem which is rather complex.   POR is
           big, it behaves pretty much like several critical
           assemblies loosely coupled and each one has different
           average values, of the delayed neutron fractions owing
           to the fact that it has different composition at that
           point in time, different weighting both the effect of
           plutonium versus uranium neutronic properties and the
           neutron fraction specifically.  And so you're rolling
           an awful lot of important information into a
           simplistic statement here.
                       I've raised questions about this in the
           context of other codes in the last year and I haven't
           heard crisp clear answers to those questions.  I don't
           know that you're doing the calculation better than
           some of the industry codes where they make claims that
           they're doing it right.
                       Somewhere I'd like to hear a clear
           explanation of how one keeps track of the local
           compositions and how that information is then
           impacting the calculation of such things as the 3D
           kinetics.  I haven't heard any of it yet.
                       CHAIRMAN WALLIS:  You need to see the POX
           -- you need to see the POX documentation.
                       MS. UHLE:  We can provide that to you. We
           have it written up, if you'd like that.
                       MEMBER SCHROCK:  I'd like to see it.
                       MR. KELLY:  Yes, we can do that.  Sure.
                       MS. UHLE:  Oh, sure.  Or we could have a
           separate briefing on the MOX development if that's --
                       MEMBER SCHROCK:  You see, in the
           documentation you're offering here, our code is like
           the government's code, and therefore it's okay. You
           guys can't challenge that because you've developed it,
           it's your documentation and we're doing the same kind
           of inadequate documentation as you do, but you've
           judged it's good enough and therefore you've got to
           accept the fact that we say it's good.  What I'm
           telling you is that it is not good engineering
           practice.  And I'm going to keep asking the question
           until I hear some better engineering answers.
                       MS. UHLE:  With respect to the MOX
                       MEMBER SCHROCK:  It has to do with the
           calculation of the reactor kinetics in a 3-D situation
           in which the composition of the core is nonuniform and
           evolving, it's different at different points in time--
                       MR. ULLSES:  I understand.  Right.   Okay. 
           I can get back to you on that.
                       MS. UHLE:  I mean I have a --
                       MR. ULLSES:  I could take a stab at it now
           or we can do it later.
                       MEMBER SCHROCK:  No, I think we need to
           get back.
                       MR. ULLSES:  Okay. We'll get back to you.
                       MEMBER SCHROCK:  Right.
                       MR. ULLSES:  I`ll bring you the
                       MS. UHLE:  Okay.  I can skip over the
           other slide. I was going to get more into 3-D kinetics
           methodologies for MOX, but I think we're going to have
           a more detailed description of that provided to you at
           a different date, if that's all right.
                       MEMBER SCHROCK:  See, the term MOX is
           generally interpreted as being -- as situations in
           which the fuel is designed to be mixed oxide. 
           Whereas, what you really have in all reactors is some
           form of MOX.  And my problem with the calculations
           that I see done is that this level of complication
           gets getting short-shrift in describing what the codes
           actually do.  With the physics it is relatively
           straight forward to understand in principle, but
           complicated to deal with in the calculations.
                       MS. UHLE:  Right.  And I can tell you that
           the way we're going to be handling the MOX cores is
           that the uranium assemblies, the U02 assemblies, they
           will be homogenized so that each -- the node -- the
           power --
                       MEMBER SCHROCK:  Have you asked yourself
           the question of why does this issue of error in
           reactivity arise when you're talking about mixed-oxide
           fuel and not for reactors that have initial uranium
                       MS. UHLE:  Okay.  With the reactor
           physics, I mean you get three different types of
           errors -- well, I mean stemming from three different
                       One is the number of energy groups that
           you have because, of course, there are -- you don't
           want to get into this.
                       CHAIRMAN WALLIS:  No, his question is
           different. I'm sorry.  He said why is MOX different
           from regular reactor because when you've got high --
                       MEMBER SCHROCK:  In principle it's all
                       CHAIRMAN WALLIS:  -- burnoff, there's a
           lot of plutonium there already.
                       MS. UHLE:  MOX is because you're going to
           have uranium dioxide fuel assemblies sitting next to
           a MOX of plutonium dioxide assembly.
                       CHAIRMAN WALLIS:  So there's increased
                       MS. UHLE:  And so -- and you get very
           different energy spectrums coming out of the plutonium
           side because of the different cross sections for the
           resonances.  And so you get this very strong neutron,
           this gradient in neutron flux between the assemblies.
                       MEMBER SCHROCK:  Clearly the more you
           complicate the spacial variation in fuel composition,
           the harder the calculation becomes.  
                       MS. UHLE:  Yes.
                       MEMBER SCHROCK:  And in mixed-oxide fuel
           meaning that you have bundles of different composition
           loaded into the reactor initially, it's going to be
           more complex then if you load it uniformly and let it
           generate its nonuniformity as it burns up.  But you
           get the same phenomena occurring to different degrees. 
           The relative consequences become more important when
           you're talking about what you're characterizing as
           mixed-oxide fuel cores.
                       MS. UHLE:  The orders of magnitude --
                       MEMBER SCHROCK:  But the phenomena are
           always there.
                       MS. UHLE:  Right.
                       MEMBER SCHROCK:  And the codes need to
           deal with the phenomena.
                       MS. UHLE:  They deal with the phenomena.
                       MEMBER SCHROCK:  Yes.  My question is how
           do they deal with the phenomena.
                       CHAIRMAN WALLIS:  I think that's where you
           have to look at the documentation.
                       MR. ULLSES:  Yes, I understand the
           question, Dr. Schrock.  I mean, I can go through an
           excruciatingly long discussion right now about
           hydrogen --
                       CHAIRMAN WALLIS:  I don't think we need
           that.  I think --
                       MEMBER SCHROCK:  What I'd like is to be
           given something to read that tells the story in a
           clean cut fashion.
                       CHAIRMAN WALLIS:  So would you agree to
           give him something to read and then we can move on?
                       MS. UHLE:  Yes.  That is an action item
           for us.  By Monday we will have a clear -- 
                       MEMBER SCHROCK:  Okay.
                       MS. UHLE:  We have it written up.  It's
           upstairs. It's upstairs.  We can go get it if you want
                       CHAIRMAN WALLIS:  Okay.  Let's move on.
                       MS. UHLE:  We`ll give you a brief
                       CHAIRMAN WALLIS:  Let's move on.
                       MS. UHLE:  Why don't we go get it.
                       MR. ROSENTHAL:  Why don't we provide him
           with the documentation, okay.  And then after he's had
           an opportunity to look at the documentation, at his
           discretion we'll schedule a morning session and we'll
           talk about MOX.  When we talk about MOX, we not only
           talk about the physics, but we'll also talk the
           neutron physics --
                       MEMBER SCHROCK:  See, my emphasis --
                       MR. ROSENTHAL:  -- we'll also talk about
           source term and other related issues.
                       MEMBER SCHROCK:  Jack, my emphasis is not
           on MOX. It's on the fact that I look at old
           documentation, which continues to be referenced, and
           what I find is that people say you do these things
           with delayed neutron yields and there's a table of
           delayed neutron yields for U-235 presented in the
           documentation in the early versions of RELAP5, for
           example.  And nothing's said one way or the other
           about does this deal with the problem that the core
           contains some other fissile nuclides and what are the
           delayed neutron fractions from those.
                       It's the latter that I'm concerned with. 
           Why did they get lost in the shuffle?  
                       When I raised it in connection with review
           of another code, I'm told that it's all done
           correctly, you just don't view it in -- yes, right. 
           Well, I'll believe it when I see it in a clean cut --
                       CHAIRMAN WALLIS:  So you're going to see
           it, Virgil.
                       MEMBER SCHROCK:  Thanks.
                       CHAIRMAN WALLIS:  And we're going to move
           on.  You're going to satisfy him with some
           documentation, otherwise the question will just come
                       So, can we move on?
                       MS. UHLE:  I think everyone was aware of
           the control rod drive mechanism issue.  The Oconee
           Unit 3 spring 2001 outage, there were circumferential
           cracking on the CRDMs.  We looked at the idea that
           there's this potential for a rod ejection because of
           the circumferential cracking.
                       The question was raised that you could
           result in, perhaps, an ATLAS because of the fact that
           you have collateral damage with the CRDM ripping off
           and taking out a bunch of the other CRDMs in the area. 
           So Research performed a worst case scenario
           calculations on the off chance that for some very
           improbable reason there was a full ATLAS.  And we did
           a 3-D kinetic, 3-D hydraulics model using the TRAC
           code.  Jack had said it was a RELAP, but we had used
           TRAC with this because we, again, want to keep
           exercising the TRAC code. And we used the Boron
           tracking to determine the effect of the RWST injection
           shutting down the reactor.
                       The results of this actually confirmed NRR
           from the analysis that NRR had done with RELAP5. And
           what it showed was that there was no new phenomena
           identified bounded by the current design basis and no
           fuel heat up was expected, no core damage was
                       We did this as part of a confirmatory
           analysis for which that was an activity that we did.
                       One thing to point out was that based on
           the results of in running these codes is that they,
           again, there are still bugs in the codes.  And one
           that we found was with respect to the Boron reactivity
                       In the PWR people don't picture -- well,
           typically you're thinking of normal operation, you're
           not picturing any boiling in the core.  And the
           reactivity coefficient for the boron, assuming no
           voiding and it was based on parts per million versus
           parts of boron per parts of liquid.  And so it could
           deal with boiling.  And what we have done is, of
           course, change it to what it should be, which is moles
           of boron per the volume of the cell that you're
           talking about.  And this was actually identified also
           in the TRAC-B code as well for the point kinetics
                       So, every time we use these codes it helps
                       MEMBER LEITCH:  So in your calculations
           you assumed that there was a partial --
                       MS. UHLE:  A full ATWS.
                       MEMBER LEITCH:  Oh, a full ATWS?
                       MS. UHLE:  Yes.  And so you're getting the
           heat up, you're turning back around and with the
           depressurization you're injecting the RWST water with
           the high boron concentration and it's shutting it
                       MEMBER LEITCH:  Okay.  So even with the
           full ATWS you're still reaching these same
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  It's a full ATWS and a
           LOCA at the same time.
                       MS. UHLE:  Yes. And Tony also said the
                       Steam-generator tube integrity.  You've
           heard that, a briefing on that before.  I think I'm
           going to skip that for reasons of time.  You will
           please note that we will be using the thermal-
           hydraulic code in the branch to look at those DPO
                       Let me get into risk-informing activities
           that we have in the branch and the use of the codes in
           those areas.
                       Of course, I think that you understand
           what we mean by risk-informing regulation.  The
           current activities we have with respect to thermal-
           hydraulics is risk-informing the ECCS rule and the
           pressurized thermal shock rule.  So 50.46 for the ECCS
           and 50.61 for the PTS.
                       You have seen or the full committee has
           seen a briefing in our risk-informing of 50.46.
                       I wouldn't say that it's really risk-
           informing, the activities are more looking at any
           modifications that can be made to Appendix K based on
           the industry's desire to reduce regulatory burden. 
           And Ron Lauben and Steve Bajorek are the technical
           leads on this in the branch.
                       So what has been looked at as an idea to
           look at the Appendix K evaluation models and note the
           real conservatisms in the code, and based on better
           science can we replace the oxidation model for heat
           generation to Cathcart-Pawel, because Cathcart-Pawel
           does a better job as far as the heat generation.
                       We also have better science now with the
           decay heat curve of 1994 standard versus the '71
           standard. We were looking at that as an option.  We've
           been running code calculations to get an idea of the
           change in the PCT based on these changes going to the
           '94 standard or using Cathcart-Pawel versus Baker-
                       MEMBER SCHROCK:  I guess we're going to
           hear more about that?
                       MS. UHLE:  Yes, in detail.
                       MEMBER SCHROCK:  In details, but in my
           mind it's just kind of strange that suddenly there's
           a large activity going on to revise what has to go
           through Congress to get approval, I think.  Appendix
           K is in 10 CFR, it's got to be -- it's part of the
           legislation is involved here.
                       MS. UHLE:  Yes.
                       MEMBER SCHROCK:  There are lots of
           complexity, but the background that's covered,
           evidently, in SECY 01-133 seems to be totally lacking.
           I don't understand how a decision can be made that we
           must deal with a modification in Appendix K without
           the technical evaluation that leads to the decision to
           do that.  Where is it?
                       MS. UHLE:  That's our stance, though, the
           division position, Research position, and we've had a
           discussion with NRR in this manner that we're leaning
           towards the idea of not modifying Appendix K because
           of the fact that we have found nonconservatisms in
           Appendix K.  And the person who came up with the 71
           times 1.2 was very good because they accounted for
           those, in a sense, conservatisms.
                       MEMBER SCHROCK:  Well, I read that so I
           know what it is.
                       MS. UHLE:  So you're the one.
                       MEMBER SCHROCK:  Well, I'm not "the" one,
           I was involved.
                       MR. KELLY:  One of the ones.
                       MS. UHLE:  One of the ones.
                       MEMBER SCHROCK:  But what I'm hearing and
           what I'm reading isn't a very accurate account of
           that; not that that's a terribly important thing.  But
           what I'm getting at here is why is a lot of activity
           going on here to revise?
                       MS. UHLE:  What is the initiative?
                       MEMBER SCHROCK:  What is the impetus to
           revise Appendix K?  
                       MS. UHLE:  Appendix K --
                       MEMBER SCHROCK:  What is the technical
           basis for it?
                       MS. UHLE:  Well, why this started was a
           petition submitted by NEI looking at replacing the 
           '71 standard with the '94 standard.  And so the idea
           of reducing unnecessary regulatory burden or --
                       MEMBER SCHROCK:  They're totally different
           things. You're comparing apples and oranges.
                       MS. UHLE:  I think -- can I finish what I
           was saying?
                       MEMBER SCHROCK:  Yes.
                       MS. UHLE:  I think it'll -- okay.
                       That's why this, we started looking at
           this one here with this idea to a risk-informed Part
           50 is where a lot of -- we were looking at changing
           Part 50, changing the regulations under this risk
           initiative, this risk-informing initiative.  And this
           work here was put in with that based on the petition.
                       MR. BAJOREK:  Jennifer, can I jump in?
                       MS. UHLE:  Yes, sure, Steve.
                       MR. BAJOREK:  This is Steve Bajorek.
                       One of the things that we're trying to
           deal with is accuracy in the various models; the decay
           heat or Cathcart model versus Baker-Just versus the
           expectation that those can be changed in an evaluation
                       I think there's been a recognition in the
           SECY paper that the '79 or the '94 standard is
           technically better than the '71 decay heat standard,
           more accurate with regards to more recent data.  And
           likewise, with the Cathcart-Pawel versus Baker-Just.
                       The expectation that seems to have been
           raised in the SECY paper is that we can just simply
           replace those in Appendix K.  The work that we have
           been doing in our branch has been twofold: (1) To take
           a look at what do you need to go from this decay heat
           standard to the '94, and there's more complications
           involved in dealing with the uncertainties.  Norm
           Lauben has been looking at that.  But the other issue
           is to what extent do the present day Appendix K
           evaluation models depend upon the conservatism that
           was inherent in the '71 plus 20 percent to cover other
                       Now, when we start to delve into this what
           we have been finding are things like downcomer boiling
           and fuel relocation would result in increases in the
           peak cladding temperature that would almost offset any
           kind of benefit that would be gained with the 1971
                       MEMBER SCHROCK:  Well, do you really
           believe that the people that drafted 10CFR back in the
           early '70s brought the uncertainty in decay power as
           taking care of unrelated uncertainties?
                       MR. BAJOREK:  No.
                       MEMBER SCHROCK:  No.  Okay.  So why is
           that brought up as an issue here?
                       MR. LAUBEN:  Norm Lauben.
                       There was an evolution and it didn't start
           out that nobody thought the decay heat multiplier, as
           you say, we dropped another degree but as time went on
           different things were discovered that was discovered
           that there was a larger conservatism in the '71 than
           was originally thought, but at the same time there
           were -- how do I want to say this -- there was
           creeping reduction in conservatism in Appendix K
           evaluation models that ate away at some of the
           increased margin that was perceived as time went by.
                       So, people then began to think, "Ah, well
           there is extra conservatism in the decay heat model." 
           But it truth at the beginning we did not believe that.
                       MEMBER SCHROCK:  Well, yes, I think that's
           a historical fact that people have thought that way
           that expressed their view, etcetera.
                       MR. LAUBEN:  Yes, right.
                       MEMBER SCHROCK:  But it's not something
           that's documented as a basis for licensing evaluation.
                       MR. LAUBEN:  And in fact -- 
                       MEMBER SCHROCK:  So it's not something
           that has anything to do with issues of whether you're
           going to change it or not.
                       Those rules were created when there was a
           lot of information that was still, basically, unknown.
                       MR. LAUBEN:  Right. Right.
                       MEMBER SCHROCK:  And did a remarkably good
           job under the circumstances.
                       MR. LAUBEN:  And may be lucky, too.
                       MEMBER SCHROCK:  I think it was --
                       CHAIRMAN WALLIS:  Well, I guess, one of
           the things said here is that it could change the
           regulations and became more realistic about decay
           heat; it would look good and industry would think they
           had gained something.  It turns out you've got to be
           realistic about some other things, which take away the
           gains from the decay heat.
                       MEMBER SCHROCK:  Yes.
                       CHAIRMAN WALLIS:  And so that it's not
           clear that there's a gain to anybody by changing the
           regulations, except the new regulations would be more
           based on more realistic physics, and that's probably
           a good thing.
                       MEMBER SCHROCK:  Well, I've probably
           gotten into this at the wrong time in our discussions.
           I know you have a presentation coming up on it.  But
           it does seem to me the starting point is thrown at
           this committee in a very strange way.  This SECY paper
           has not been reviewed yet by this group. Okay. I don't
           know what in the world it says or why they think
           there's a sound basis.  All I hear is rumors to the
           effect that it is something that was initiated by NEI.
                       MR. LAUBEN:  Is that true with the
           activities with the --
                       MEMBER KRESS:  Yes, we have.  Not this
                       MR. BOEHNERT:  Yes, not this Subcommittee. 
           The full committee of ACRS I think, because it's
           handled under subcommittee.
                       MR. LAUBEN:  Have you reviewed all the
           other copies of this?
                       MEMBER KRESS:  Yes.
                       MR. BOEHNERT:  It was handled by another
           subcommittee, that's my --
                       MEMBER SCHROCK:  Well, what I'm
           challenging here is why does the Research branch of
           NRR get deeply engrossed in a lot of considerations,
           it's obviously an expensive thing to do, to address a
           problem which somebody has told them is a change that
           has to be made?  On what basis can a decision such as
           that be made without the technical work preceding the
                       MR. LAUBEN:  Of course the technical work
           has to be done.
                       MEMBER SCHROCK:  Yes.
                       MR. LAUBEN:  And I think 01-133 says the
           technical work must be done.  And if the decision
           comes that we shouldn't change it, then we won't
           change it.  
                       MEMBER SCHROCK:  My concern was, pure and
           simple, that this is something that's going to get
           railroaded through despite everything.  And you're
           saying that it isn't true.  All right.
                       MR. AYER:  Well, let me jump in.  This is
           Charles Ayer from Research. Let me just to correct the
           record a little bit.
                       The SECY paper we're not risk-informing
                       MEMBER SCHROCK:  Yes.
                       MR. AYER:  It was looking at several
           issues, part of which was the Appendix K model for
           decay heat.  The petition to change the decay heat
           came along later, and that was just something that's
           come in very recently, but that was not the driving
           force --  
                       MEMBER SCHROCK:  Okay.  
                       MR. AYER:  -- the NEI submitted a petition
           and the agency jumped up and ran off to limit it to
           50.46. It came in subsequent  wanted a simple change
           on 50.46.  This other effort to risk-inform, which is
           also looking at the large break LOCA and loss of
           power.  But that effort had been going on and is going
           on.  At the onset we're looking at the technical basis
           for the smaller needs that Jack's branch is working on
           to see if you can incorporate '94 decay heat, to see
           what other things would have to be incorporated and
           perhaps be more realistic in the other areas.
                       But I just wanted to make it clear this
           wasn't initiated because of a petition from NEI.
                       MR. LAUBEN:  As a matter of fact, Paul,
           you were at several workshops last year in which this
           group was starting to deal with it, so you know, so
           you knew this was augmented to the initiative.
                       MR. BOEHNERT:  Yes, that's correct.
                       CHAIRMAN WALLIS:  Well, I think the
           message for us is I think we would have said that you
           could sort of change this decay heat code independent
           of all the other considerations.  And let's do it,
           it's an obvious thing to do under the ACRS initiative. 
           We ought to follow that line.  And what we are being
           warned about here is if you do that, you're giving up
           some conservatism which you really need to cover some
           of these other things, and therefore you should be
           more careful about saying, viewing the decay heat code
           as something completely independent that you can fix
           and then you can deal the other part separately.
                       MEMBER SCHROCK:  Well, another way of
           looking at it is that there is a very simplistic
           rather conservative scheme for licensing put in place
           in the early '70s that's antiquated, it was
           grandfathered when the new rule was passed in '88. 
           And now the issue is, does it make sense to reduce
           conservatism in an antiquated method.  That's an
           overall issue, it seems to me, and it needs to be
           addressed, and it ought to be addressed by this
           Committee, too.
                       To me it makes no sense whatsoever to say
           we are going to go back and take all the conservatisms
           out of an antiquated scheme and expect that it's going
           to be technically sound in the end.
                       MR. ROSENTHAL:  We briefed about two weeks
                       MR. KELLY:  Two weeks ago, yes.
                       MR. ROSENTHAL:  We briefed the PRAs and
           members of the subcommittee --
                       MR. LAUBEN:  And this subcommittee, too.
                       MR. ROSENTHAL:  And this subcommittee.
                       MR. LAUBEN:  We briefed three
                       MR. ROSENTHAL:  And now we have some more
           technical work to do, and we would more than welcome
           an opportunity bringing the technical work before this
           Subcommittee.  I think it would be very appropriate.
                       MEMBER KRESS:  But I think from the point
           I've heard in these other reviews that we're basically
           on the same page you are with respect to that issue. 
           They're not going to just go in and blindly change
           that Appendix K.  They're going to look at what the
           implication are.
                       And so I think we're closer to your side
           of the table than you might think of.
                       CHAIRMAN WALLIS:  We probably have to move
                       MEMBER KRESS:  Yes.
                       CHAIRMAN WALLIS:  And we're going to have
           a whole meeting on 50.46 some day.
                       MEMBER KRESS:  Right.
                       CHAIRMAN WALLIS:  And we can't dig into
           that in depth today.
                       MEMBER KRESS:  Yes.  Okay.  
                       CHAIRMAN WALLIS:  But we've been warned,
           I think, that we've got to worry about some of these
           things, which has been very useful.
                       MS. UHLE:  The point of slide too is to
           point out that with respect to your concern about
           doing the technical work to make sure that this is a
           viable technical approach is that we will be running
           and analyzing a great deal of cases with respect to
           any of these activities.  And it was with support that
           we have given to NRR concerning the effect of the
           downcomer boiling, especially as being a primary
           concern that is shaping the technical position that is
           leading in a direction that I think is very consistent
           with yours.  So we are using these tools for their
                       Again, in the future we would also be
           using them in the SECY paper to look at certainly the
           effect of redefining large break LOCA size, looking at
           success criteria evaluation for the PRA runs and the
           effect of the different restrictions concerning delay
           diesel generator start time, loss of offsite power and
           signal failure.  But, again, we will -- all of these
           activities 54 -- or the risk-informing Part 50 are
           going to be made, you know, using the available tools
           and, as well as the knowledge and the analyses of the
                       MEMBER KRESS:  My next door neighbor in
           Oak Ridge has asked me to be sure you pronounce his
           name correctly.  It's Pawel, Dr. Pawel; just as if it
           were P-A-U-L.
                       MS. UHLE:  Pawel.
                       MEMBER KRESS:  Yes.  Not P-A-W-E.  It is
           spelled correctly, but it's not pronounced Powell,
           it's Pawel.
                       MS. UHLE:  I know how he feels, because
           nobody pronounces my last name right either.
                       MEMBER KRESS:  I know this is trivial, but
           it upsets him.
                       CHAIRMAN WALLIS:  Jennifer, are you going
           to take a long time now?
                       MS. UHLE:  No. I can skip over 61.  We're
           doing the same thing with 50.61.  We're running the
           tools; you had a briefing on that.  We've made sure
           that the calculations are consistent with data that
           was taken at OSU.  So we're looking at the idea of
           when we use these potent codes how can we prove that
           -- or at least appease the masses that the answers
           that we are generating are acceptable.  We're not
           believing everything that comes out of the code, that
           we're skeptical about it.
                       With respect to AP1000 design
           certification, we had an NRR user need request
           concerning looking at the Westinghouse assertion
           concerning the scaling of AP1000 is consistent with
           the AP600 work, and that they're claiming no
           additional testing is required and minimal code
           modifications would be required.  That's the
           Westinghouse position.
                       So NRR requested technical assistance from
           Research to review these assertions, identify what
           code versions should be used if phase 3 were to take
                       And we for the small break loss of coolant
           accident, I know a lot of you are involved in the
           adequacy assessment of RELAP5 over that 5 to 6 year
           period.  TRAC had not been -- we didn't have a program
           to do adequacy assessment for small break LOCA on the
           TRAC code, so the RELAP code will be used for the
           AP1000 phase 3 for small break.  And in phase 3 if it
           were to come in, the TRAC code would be used for the
           large break LOCA application.
                       Now, one thing of note is, and an activity
           that has stemmed from this initiative is that the
           AP600 had a lower power density.  So PCT values
           predicted by TRAC were below the limits, the 2200.
                       AP1000 has an increased power density. We
           realized that there won't be as much margin there and
           we're based on calculation run with the reflood 
           models in TRAC.  We're expecting that it would be over
           the limit, not because of the actual physical
           processes but because we have a lot of conservatism in
           the TRAC large break model.
                       To remove some of this conservatism, will
           we do a preliminary or an interim model development on
           the reflood model.  Bajorek is working on that
           currently with Weidong Wang of the staff.  And it is
           hoped that or it is the goal to have that in by, say,
           the spring or the summer and start doing some
           developmental assessment work on that version for the
           consolidated code.  So by the time the consolidated
           code is finished we will have, you know, this interim
           reflood model developmentally assessed and use that
           for the AP1000 submittal.  Because RELAP large break
           model tends to be nonconservative and TRAC is too
                       Now, I don't want to confuse you with the
           fact that the RBH, the rod bundle heat transfer
           program.  That's focused on developing a mechanistic 
           model for reflood.  And we're thinking 2004, 2005 time
           frame for it to be the model in the code.
                       What we're doing for the AP1000 work is
           more of a -- we're simplifying what's currently in the
           code with something that's more of a -- Joe, do you
           want to say what you're doing?  
                       I don't want to say it's simple, but it's
           not the mechanistic model with a droplet diameter and
           the interfacial area tracking, and what have you. 
           It's going to be easier to follow than what's
           currently in the code. It will get rid of the
           conservatisms that are coming from too much
           entrainment at the punch front.  And we're hoping to
           have that done by the spring/summer time frame.
                       Do you want to --
                       MR. KELLY:  I'll have several slides in my
           presentation, so I'll wait for that.
                       MS. UHLE:  Okay.  I didn't mean to say
           what you're doing is simple.
                       Again, we know that the phase separation
           model in the RELAP5 code was determined to be
           inadequate for the phenomena. It turned out that the
           AP600 had so much water reserve that it didn't make a
           difference in assessing collapsed liquid level, so the
           code was determined to be adequate for the AP600
           calculations with the fact that they have a higher
           power density and the inventory to power ratio of the
           AP1000 is reduced.  We realize that the phase
           separation model for the stratified conditions during
           ADS 4 time frame is going to be of higher priority, so
           we're looking at that.
                       Steve Bajorek will talk about that in more
                       We have there, too, for the PBMR design
           certification that we're expecting to come in.  I
           think you know the background on that with the idea
           that it is now a helium cooled/graphite moderated
           reactor.  It's a little bit different than the light
           water designs that we currently deal with. It's a
           pebble bed rather than the force flow parallel to the
           bundle situation that we currently deal with.
                       We've drawn the conclusion that we would
           be upgrading -- or not upgrading, but extending the
           TRAC code and the MELCOR code to be used in real
           certification if it were to come in.  And we have
           identified what needs to be changed in the code, and
           you have a list of them on your slides.  I don't need
           to go into them.  I don't think --
                       CHAIRMAN WALLIS:  You're worried about
           water ingress?
                       MS. UHLE:  Yes, water ingress because of
           the reaction with the graphite.  Because you have the
           second -- well, you have the cooling on the -- you
           have the bring cycle but you've got the compressor in
           the intercooler.
                       CHAIRMAN WALLIS:  The intercooler is a
           water cooler?
                       MS. UHLE:  Yes, so you can get water
           ingress.  We can do water ingress and air ingress at
           the same time and we have it working for the helium. 
           So we'll be able to run the whole gambit of the
           accident scenarios with respect to the pebble bed.
                       Now, we do have some code development to
           do as well as benchmarking, and we'll be doing that
           in-house as well at Las Alamos National Laboratory.
                       CHAIRMAN WALLIS:  Hydrogen and CO --
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  -- process, or whatever.
                       MS. UHLE:  Yes.  Modifications also had to
           be made to MELCOR and we've identified those, and
           those will be done at CND and National Laboratory with
           staff involvement.
                       So that's where we're heading.  We're
           going to not get away from this.  It was thought that
           maybe we would use a special code for the pebble bed. 
           Again, we're focused on this idea of having modules
           that only need to be exercised if they need to be
           exercised to get this approach with the consolidated
           code having one code.
                       MEMBER KRESS:  Well, what's the purpose of
           looking at the water ingress for example.  There are
           no graphite structural ingress in there, are there?
                       MS. UHLE:  There are no what?
                       MEMBER KRESS:  Structural ingress in the
           graphite?  There's only the spheres of graphite isn't
           there, they're not structural.  So that's the --
                       MS. UHLE:  It's a fuel damage issue.
                       MEMBER KRESS:  We're looking to see
           whether in the break the spheres --
                       MS. UHLE:  Yes, that would be in the
           severe accident situation.
                       MEMBER KRESS:  -- break or something of
           that kind?
                       MS. UHLE:  Or would oxidize, getting
           brittle, break and then get the fission products out
           because the pebbles are the -- 
                       MEMBER KRESS:  But you have no data on
           sphere strength.  I don't understand what you will do
                       MS. UHLE:  That's the last bullet.  Data
           for benchmarking.  
                       Originally in the budget this year there
           was going to be some money for fuels testing.  
                       MEMBER KRESS:  I don't understand --
                       MS. UHLE:  As the submittal comes in, that
           will be ramped up to meet the data needs. We're not
           going to use the code unless it's assessed.
                       MEMBER KRESS:  You're going to degrade
           these spheres, make them go through the separating
           devise and see if the break --
                       MR. ROSENTHAL:  All right. I'll be fast. 
           Presentations of the pebble bed say it's a very benign
                       MEMBER KRESS:  Yes.  Absolutely.  Okay.
                       MR. ROSENTHAL:  And so we started asking
           ourselves, okay, what about the accident provisions. 
           And bare in mind that design bases accident goes
           beyond design base, or even that language is not yet
           defined for this system.
                       MEMBER KRESS:  Yes.
                       MR. ROSENTHAL:  And we may be talking
           about a spectrum of accidents, one accident, whatever. 
           Okay.  And so we started saying, okay, what kind of
           issues might we face, and we recognized that we needed
           to start thinking about well what happens if we put
           air in there, or water in there instead of helium, and
           what kind of chemical reactions would take place, or
           whatever.  And because of the time it takes to develop
           a code, we needed to get a jump start on these issues. 
           And that's really where we are now, you know, we
           haven't thought it through. We're still defining the
           research plan for it.
                       MEMBER KRESS:  My question is --
                       MR. ROSENTHAL:  But the concern is --
                       MEMBER KRESS:  Yes. My question is are you
           concerned about degradation of strength of these
           spheres or are you worried about the effects on
           fission products, or both?
                       MS. UHLE:  Both.  I mean, you get the
           oxidation action causing fuel heat up and then you're
           also getting fuel damage and how that's going to --
           essentially if there's no containment, how the fission
           products would be escaping because of that.  So with
           respect to the why in the TH code are we worrying
           about that?  Well, we're going to tell you how much
           water comes in and what state it's in.  Is it steam,
           what temperature, what have you and get the oxidation
           reaction  and then, of course, going into the
           theorizing for the core degradation.
                       CHAIRMAN WALLIS:  So you're identifying
           all the things that you're TRAC-M modification have to
           be able to handle, that's really the message you're
           giving us?
                       MS. UHLE:  Yes.
                       MEMBER SCHROCK:  What doesn't come through
           clearly to me is why one would choose TRAC-M as a code
           to analyze this new system.
                       MS. UHLE:  It's probably at this point in
           time --
                       MEMBER SCHROCK:  I mean almost none of the
                       CHAIRMAN WALLIS:  It's the only one they
                       MEMBER SCHROCK:  Well --
                       MS. UHLE:  No, that's not right.
                       CHAIRMAN WALLIS:  It's the only one they
           will have.
                       MS. UHLE:  No, that's not the answer. 
           I'll give you the answer.
                       MEMBER SCHROCK:  But they're so different
           from one another and --
                       MS. UHLE:  Well --
                       MEMBER SCHROCK:  -- all these gory details
           of what goes on in water reactors has no impact. 
                       MS. UHLE:  Again, it's going to be
           physical models that are going to be different.  You
           have -- I mean, if you look at the code as far as how
           many hundreds of thousands of lines it may be, the
           physical model package, I mean it's dinky.  It's maybe
           where the correlations are, maybe 400 lines or more,
           or less. I mean, it's not -- putting in a different
           wall drag or a different -- you know, effective
           conductivity for the fuel.  I mean, that's small. 
           What's in the code is the setting up of the matrix, it
           is the communication of the data between the cells  if
           you have -- like in a 3-D.  We have a 3-D vessel here
           of porus media. The hydraulic model in TRAC is
           essentially a porus media 3 dimensional model with
           wall drag, that is assuming the flow is parallel. 
           Well, now the flow is going to be over spheres so we
           have to replace that wall drag term with something
           that represents the fact that you're flowing over a
           pebble bed.
                       So, looking at all the codes that are out
           there, TRAC was the one that had the less amount of
           work done.  We already have helium as a working fluid
           in the code.  Again, we have the porus media hydraulic
                       We can do -- on the intercooler side, the
           secondary -- if you want to call it the secondary
           side, you know, we have the water loops for the heat
           transfer.  We have a turbine model that we have to
           modify so that it's a two-phased turbine.  But, you
           know, we have the equation set up and already
           dispertized; it's a matter of putting in different
           physical models.  But that's the, in some sense, the
           easy part.
                       MEMBER KRESS:  But you could have a break
           in the intercooler, and the water is a lot lower
           pressure than the helium.  How do you deal with that
           in terms of ingress to the water, or you haven't
           gotten that far yet?
                       MS. UHLE:  Well, I mean we are modeling
           the -- you mean, the intercooler breaking and not
           flowing into the helium, because there are two
           different sections.  And so if we had an intercooler
           break, it'll just be like faster flow out and cooling
           down; it'll be like a main steam line break in some
                       MEMBER KRESS:  Yes, but I presume if
           you're given a small leak, you know, have a crack in
                       MS. UHLE:  Yes.
                       MEMBER KRESS:  And it gets some water
                       MS. UHLE:  Into the helium?  Sorry?
                       MEMBER KRESS:  How do you get water into
           the helium is my point?
                       MS. UHLE:  Oh, how do you get the water? 
           Well, for instance, if a steam generator were to
           rupture, the same kind of situation where it's passing
           over, if you get the water in -- oh, you're saying the
           helium's higher pressure. Oh, I see.
                       MR. ROSENTHAL:  Let's not get too far
                       MEMBER KRESS:  It's a technical issue.
                       MR. ROSENTHAL:  At one time a few weeks
           ago I asked at this plant if it had MSIVs, and I was
           told, well MSIVs is the wrong term.  There would be an
           MHIVs.  And so I said okay, is this plant going to
           have MHIV?  And I was told we don't know yet.  
                       So let's not get too far out ahead of the
           planning cycle.  What we know is we started.  We
           really need tools to do analyses.
                       MEMBER KRESS:  And that's the main thing.
                       MS. UHLE:  But in the sense that you can
           have a lower pressure or you can have a break in your
           helium side, you get loss of forced circulation and
           you still have hot graphite, you're at a low pressure,
           water can get in.  Because -- okay.
                       MEMBER KRESS:  I'm sure there's some areas
           that we can -- again --
                       CHAIRMAN WALLIS:  We can't spend an hour
           on the pebble bed reactor.  We have to move on.  Yes,
           they're just giving us an overview, I think.
                       MS. UHLE:  Yes.  We will be using the code
           and, again, the changes in the physical models are --
                       CHAIRMAN WALLIS:  And you're thinking of
           all the things you need to put in that code, you need
           to build a model.
                       MS. UHLE:  Yes, and we have done that or
           in the process of doing that.
                       CHAIRMAN WALLIS:  And when are going to be
           ready to run?
                       MS. UHLE:  Well, the work scope for next
           year is putting in the physical models for next year
           and finding data for benchmarking and doing modeling.
           So by next time we meet in front of you, we should
           have a pebble bed.
                       CHAIRMAN WALLIS:  I just hope that you've
           got models up and running before someone's already
           made a decision for license on what the design bases
           accidents are and all those sorts of things.
                       Do you actually have put in inputs to give
           so quality decisions are made?
                       MEMBER KRESS:  Well, is one of the models
           going to be the fusion of water vapor in the graphite
           spheres and what is the chemical reaction?
                       MS. UHLE:  That would be the MELCOR side.
                       MR. ROSENTHAL:  We may do that in MELCOR
           fusion and hydrogen.  We've got two major efforts. 
           One is TRAC and the other is MELCOR.  
                       At one time we thought that -- just
           conceptually that many of the pebble bed issues really
           would be more chemical type issues and that the MELCOR
           frame would be the place to focus.  Then at the
           experts meeting -- but we still had money in for TRAC. 
           Actually, it was Andy Kadak that kept bringing up
           issues of reactivity events that might occur with
           restacking or you lose the pressure, the walls move,
           or stuff like that.  Well, again, we had PARCS again
           with TRAC.  And so PARCS TRAC becomes the natural
           place for us to want to explore that.  But we really
           are at the level of building the MELCOR models,
           building the TRAC as tools for what we don't know yet.
                       MS. UHLE:  I just want to point out with
           looking at the kinetics, since that's been brought up,
           we're really benefitting from the MOX program.  I
           can't believe I'm bringing that one back up.  But the
           things that are immediate is the soon to be needed for
           the pebble bed work is similar to what has already
           been for MOX.  And so what has to be done for MOX is
           a cylindrical co-ordinate system, but that's pretty
           simple to do.  And the fact that the control rods are
           in the peripheries, we would need a transport in that
           area, but we have that for MOX already, and that's
           currently being tested.
                       So, we're using what we already have.
                       All right. So I'm going to summarize.  I
           think this was the slide that Professor Wallis has
           been looking for.
                       CHAIRMAN WALLIS:  So we can get close to
           the end?
                       MS. UHLE:  Yes.  I don't know if it's the
           end of my life or my career, or at least my
                       The branch provides technical support to
           the offices as needed, and we use the analytical tools
           and, of course, the analyses capabilities of the
           branch to meet those needs.
                       We're currently looking, the applications
           we're looking at are associated with licensee
           submittals, such as the power upgrades and the MOX
           fuel.  Generic issues such as the CRDMs, steam
           generator tube integrity.  Risk-informing activities,
           50.46 and 50.61.  And design certification, AP1000 and
           pebble bed.
                       We realize that we will have to make to
           improvements to these codes as emerging issues arise
           and, again, we're focusing on doing that more in an
           in-house fashion looking at perhaps coupling to other
           codes as needed rather than using separate codes with
           the same functionality. We're going to get away from
           that.  We're only going to use -- or only use what we
           need to versus having ten codes in our code suite for
           just TH.
                       And, of course, we're doing internal model
           improvements such as for the AP1000 case.
                       Jack had talked about this, and I
           mentioned it in the introduction, is that we have
           hired -- we are in process of hiring entry level
           employees as well to round out the technical
           capabilities of the branch.  Because we are actually
           busier now than we have been in a while.
                       It's not just going to be for thermal-
           hydraulics.  It's also computation of fluid dynamics
           as we start to use CFD more as a tool, especially with
           the pebble bed work CFD will be used in the single
           phased situations.
                       The severe accident in the fuel behavior,
           we'll be ramping up the program and making a strong
           connection in the branch so that we can work
           seamlessly across the sections.
                       MEMBER FORD:  Could I just ask a question? 
           Why entry level?
                       MS. UHLE:  Because there's a lot of -- if
           you look at the Office of Research, there's a lot of
           experience in the Office of Research.  And so with
           staffing issues, we're not allowed to be top heavy and
           all 15-10s there's some --
                       MEMBER FORD:  Six to 1 ratio or something?
                       MS. UHLE:  Yes.  There's some, you know,
           there has to be some ratio.  And this idea of
           everyone's going to start to retire, we need to bring
           in entry level and mentor and, you know, have a more
           gradual --
                       MEMBER FORD:  I wasn't thinking of the 60
           year olds, I was thinking of the experienced 40 year
                       MS. UHLE:  Experienced 40 year olds.
                       MEMBER FORD:  Given the fact that you've
           got a lot of workable --
                       MS. UHLE:  We found some positions for 15s
           in the branch that we are hiring in the severe
           accident as well as the fuel behavior.  In thermal
           hydraulics, if you look at who has been hired, they've
           been at the higher grade levels.  So it's not all
           entry levels. 
                       I say entry levels, that's in some sense
           we are more active in the entry level hiring because
           there's more positions available.  But the office is
           looking at, you know, the higher grades as well.
                       MEMBER KRESS:  Are any of those new hires
                       MS. UHLE:  Yes, they're all here.  You
           guys want to stand up.  
                       MEMBER KRESS:  They're all here.
                       MS. UHLE:  Steve Bajorek.  Da, da, da. 
           He's our SL, senior level scientist. He's our
           experienced -- you're at least a 40 year old.  Okay. 
                       Joe Kelly, you know Joe Kelly.  He is --
           yes he's another -- he's another 29 year old.
                       MR. BOEHNERT:  I think, Jennifer, you're
           going to have to give your age now.
                       MS. UHLE:  32 November 23rd. I just turned
                       MEMBER KRESS:  You're not counted in the
           new hires, are you?
                       MS. UHLE:  What?
                       MEMBER KRESS:  Are you one of the new
                       MS. UHLE:  No. I've been demoted to
           assistant branch chief.  They won't let me touch the
           code anymore.
                       CHAIRMAN WALLIS:  Jennifer, we're way
           behind in time.  How long are you going to go on with
                       MS. UHLE:  Chris Murray.  For
           introductions, it's quick.
                       Chris Murray's from Penn State University. 
           Tony Ullses from NRR.  He's been sparing with
           Professor Schrock there for quite a bit.
                       And Joe Staudenmeier from NRR.
                       Chester Gingrich has been in severe
           accidents. He was doing some thermal hydraulics work,
           now he's going to go back to severe accidents.
                       And then, of course, there's Weidong Wang
           in the back.  Shanlai Lu and Jim Han is doing analysis
           for us in the back.  And Dave Bissette lead on the PTS
                       CHAIRMAN WALLIS:  We're severely behind in
           time.  Of course, you have given us more detail in
           some of these things, since you were going to
           summarize. Does that mean that we can move faster with
           some of the later.
                       MS. UHLE:  I think the question is how
           many questions get asked.
                       CHAIRMAN WALLIS:  Well, you had a
           tremendous amount of stuff.
                       MS. UHLE:  Well, when I went over it in my
           head, it went very fast.
                       CHAIRMAN WALLIS:  We need to be finished--
           or you need to be finished by 1:30 because we have
           another group, a very different group coming in and we
           can't short change them.  So we're going to take a
           break now and then maybe you can work with your
           colleagues to get us through on time.  You work with
           your colleagues to get us through on time.
                       And I'm a little nervous about Joe Kelly,
           he always runs over.  Maybe we could find a way to
           prevent that happening.
                       So we'll take a break.  Thank you very
           much.  And we'll start again at 20 to 11:00.
                       (Whereupon, at 10:25 a.m. off the record
           until 10:40 a.m.)
                       MR. KELLY:  My name is Joe Kelly, and I'll
           be talking about the TRAC-M code consolidation and
                       Now, the last time I was in front of this
           Subcommittee I was up here for 6« hours.  And since
           we're already an hour behind schedule, Professor
           Wallis is concern is well taken.
                       So this presentation really is three
           presentations in one.  I was going to talk about the
           code consolidation status followed by Jennifer Uhle
           talking about the SNAP development that's the
           graphical user interface.  Then I was going to talk
           more about our long term development plans and a
           movement about how we're going to integrate some of
           our stand alone programs into the code development. 
                       So what I'm going to do is condense the
           code consolidation status, you've heard a lot of this,
           in half, and Jennifer is going to skip this
           presentation, because you've hard about SNAP before,
           and then I'll try to give most of what I had planned
           to give.
                       When we first started this program back
           almost 5 years ago, we laid out five areas that we
           wanted to make improvements in.  Modernize the
           architecture, accomplish the code consolidation to
           conserve resources, improve the ease of use, accuracy
           and numerics.  And I was going to say something in
           each of those areas, but I'm going to shorten it
           because first I what wanted to do is give you an idea
           of where we are today.  And that should somehow avoid
                       Take my word for it.  The colors on the
           view graph are much prettier than the colors here. 
           That's really horrendous.
                       But anyway, this is where we are today. 
           We have accomplished the modernization and the
           functionality. We have parts and functionality of
           TRAC-B and RELAP5.  We do not have physical models of
           those codes, nor do we intend to implement all of the
           physical models of those codes.
                       What we're working on at the moment is
           called the component mapping, and that's the way that
           you take your RELAP5 component through the SNAP
           graphical interface and translate it to a TRAC-M
           component.  And that's what's going to enable us to
           take the RELAP5 input deck, read it in and run it with
           the TRAC-M code.  This work is almost complete.  This
           line is supposed to show about where we are.  It will
           be complete shortly after the beginning of the year,
           at which point we'll start a development assessment.
                       Now, originally the idea was to start the
           assessment and let the model deficiencies from TRAC-M
           show up as a result of the assessment.  Then when you
           identify a deficiency, go look at them.  First, go
           look at the models in the other code and try and make
           a judgment that, say, interfacial drag in TRAC-B is
           better than TRAC-P, etcetera, and then bring that
           model in.  And that would then be a cyclical process.
                       Now, we're still going to do that to some
           extent, however there are two deficiencies that
           immediately showed up. The first is rod bundle
           interfacial drag, and that's what we've alluded to in
           the Peach Bottom Turbine Trip when Jennifer was
           talking about that.  We simply couldn't predict the
           action in a void track and operate the BWR accurately
           enough.  So what we're going to do is implement,
           again, basically the interfacial drag and interfacial
           heat transfer routines from the TRAC-B code to be used
           only for BWR channels and probably also the BWR core,
           but not globally.
                       Likewise, this is a deficiency that has
           been identified in the reflood model.  I'll talk a
           little bit more about that.  That's what I'm working
                       These will feed in as soon as they're
           finished through developmental assessment, and we'll
           have roughly about a six month period where all the
           models of the code will be frozen and go through the
           entire assessment matrix and then that leads to
           releasing the consolidated code at the end of calendar
                       CHAIRMAN WALLIS:  So maybe by the middle
           of next year or something you can show us some of your
           development assessment work?
                       MR. KELLY:  Yes.  
                       These are the type of slides I'm not going
           to belabor.  The only thing I want to point out on
           this one is that we have something called an exterior
           communication interface, and that was built in to
           allow us to very easily couple the other codes or
           special modules into the codes for capabilities that
           we don't either have in TRAC-M or don't want to build
           in.  It's already been done in an explicit with the
           REMIX code, the PPS calculations, and also we've done
           a preliminary coupling with the CONTAIN code.
                       We're skipping the SNAP presentation, and
           I'm going to not belabor this also, but we've put a
           lot of work in the draft communication interface
           making it easier to use.  So if you ask our new group
           what is their highest priority item, this is it. 
                       Most of what we need is going to be done
           in early 2002, but the playback capability will be
           mid-2002 and interactive display with user feedback,
           that is where you can run it like a simulator mode, is
           sometime in the future.
                       Documentation was mentioned earlier. 
           Documentation is a very important step and it has to
           be a continuing effort over the life of this project.
                       CHAIRMAN WALLIS:  Is it true that the code
           has not yet run?
                       MR. KELLY:  Excuse me?
                       CHAIRMAN WALLIS:  The question I get is
           that it hasn't yet run, because it hasn't yet done
           these PWR transients or PWR LOCA or anything?
                       MR. KELLY:  No, we did those.  No.  The
           code runs and it has been all throughout the process. 
           We did the development that way.  And there are
           several hundred test problems designed with each
           developmental version.
                       I shouldn't have skipped probably over
           this.  It's seeing results of TRAC-M coupled to PARCS
           for the Beach Bottom Turbine Trip as well as a main
           steam line threat.  So that is TRAC-M doing those
                       We can do BWR to our transients now, the
           reason I say early 2002 here is so that we can read in
           a TRAC-B input deck, and existing one, and run it in
           TRAC-M.  All that capability is there.  But the reason
           it has this date on it is for the upgrade to the
           interfacial drag package.  Which Tony Ullses is trying
           to quickly put that in to see if it would work and
           make the improvements that he needed for Peach Bottom,
           but we want to put it in a more correct way according
           to what we call a low level modularity.  And so that's
           when this work will be finished.
                       For the SBLOCA, I don't know that we've
           actually run any of those.  The completion date here,
           though, is for the component mapping, you know, when
           that development work will be finished.  And that's
           when the assessment for SBLOCA applications will
                       For large break LOCA, we could do a large
           break LOCA now but from my standpoint the reflood
           model was flawed so that this is the date by which
           we'll have an interim reflood model and we'll start
           doing the reflood part of the assessment matrix.
                       MS. UHLE:  Joe, can I just clarify one
           thing on that.  I'll only be a second.
                       This is the last --
                       MR. KELLY:  Just don't get my slides out
           of order.
                       MS. UHLE:  I know.  I am just going to --
           this was going to be my presentation on the buoy. 
           Again, here, with respect to RELAP release, we have a
           RELAP5 version completely finished for the post
           processing and the model editor where you're dragging
           and dropping models.  We can interact with that
           display.  You want it in a simulator mode already with
           RELAP and TRAC.  The date here being future is that
           with the idea of having -- we have a three dimensional
           model and right now when you look at the playback,
           you're seeing it in 2-D.  We want, for the ease of use
           for the user, extend that so that you can represent
           the three dimensionality in a more easier way.  So
           that's why under this there's a future, although we do
           have the ability.  We showed you that last year,
           running of TRAC in an interactive mode while we opened
           valve and saw it blow down.  So that's been in for two
           years -- I mean, for a year.
                       And in early 2002 being able to run,
           taking a RELAP5 input deck and converting it to TRAC
           and doing the drag and drop through the TRAC model,
           that's the last bit that we're doing right now.  And
           also the plotting here with the mid-2002 date.  Again,
           that's associated with three dimensionality.  We can
           2-D plot now already.  We want to be able to 3-D plots
           very easily to get the surface plot of the core boil
           fraction and the 3-D kinetics.
                       MR. KELLY:  Good.  Thank you, Jennifer.
                       CHAIRMAN WALLIS:  I notice the
           documentation is a continuing effort.
                       MR. KELLY:  Yes.
                       CHAIRMAN WALLIS:  Doesn't the
           documentation come first or do you write the code and
           then figure out what you did and write up the
                       MR. KELLY:  As Jennifer said earlier, we
           have conformed with a fairly rigid SQA, certainly
           compared to anything that's ever been done with NRC
                       CHAIRMAN WALLIS:  Then this documentation
           should be in good shape.
                       MR. KELLY:  Yes, but each piece, each new
           piece has to be folded in in the overall
           documentation.  And, for example, it was mentioned
           earlier that the TRAC manuals were extraordinary and
           it's hard to find your way around in some of them. 
           Rewriting all of that from scratch is a major task. 
           And what we're doing at the moment is basically
           putting in the pieces that we're changing.  We do need
           to go and make all the whole restructure done but
           that's a huge effort and we've connected randomly to
           make it work at the moment, but we are going to --
           that's why somebody has to start and keep working at
                       CHAIRMAN WALLIS:  But it's important. The
           way you present the documentation is important; that's
           what's out there, people look at it.
                       MR. KELLY:  Yes.
                       CHAIRMAN WALLIS:  It's got to be credible
           and not have typos and all the usual stuff.
                       MR. KELLY: Right.
                       MR. BOEHNERT:  Historically what's
           happened is the documentation was always put off the
           end and then somehow it never got done.
                       MR. KELLY:  Right.  What we're trying to
           do is have the people as they develop a model or
           implement a component do the documentation for that as
           part of the SQA.  But it's still does need to get
           folded in better to a master document.  We're not
           there on that yet.
                       CHAIRMAN WALLIS:  As I said earlier, we
           can help in the early reviews of this documentation.
                       MR. KELLY:  That would be very good.
                       CHAIRMAN WALLIS:  We'd like to do so.
                       MR. KELLY:  We also need to, as you know,
           improve the code accuracy.  And really what I wanted
           to say here is we're beginning now to put the models
           in the code.  And that's a huge effort, but what we
           focused on for the last few years is putting in
           capabilities of the functionality consolidating.  But
           we've got a lot to do here and this is just starting. 
           But that's not part of the code consolidation, that's
           part of us evolving to this actual state-of-the-art
           thermal hydraulic code.
                       CHAIRMAN WALLIS:  Beginning isn't a good
           word, though.
                       MEMBER SCHROCK:  One of the problems has
           been that the codes run part of the way through a
           problem and then crash, and then people fix it up and
           run the rest of it.  In my mind that leaves a lower
           level of reliability when that kind of thing happens.
                       Do you have an objective for this code
           that that is not going to be allowed or is this going
           to be a continuing problem?
                       MR. KELLY:  What we have the objective of
           is to improve the robustness of the code and that is
           just what you are talking about.  It is making the
           code be able to run to completion and not only run to
           completion, but run without these periods where it
           just grinds to near like halt and you go to, you know,
           10-6 time steps.
                       So what we're going to do is starting in
           the assessment when we start running in to those
           problem, the code either fails or it has significant
           swim outs, we're going to, in effect, ship that
           problem off to our numerics guru, otherwise known as
           Professor John Mahafty, who is going to help us track
           down the root cause of it.
                       Sometimes it'll be the numerics.  You
           know, some like the way the water tracking interacts
           with level tracking of whatever.  Sometimes they will
           just have to be an old condition numerical, an old
           condition physical model, the physical model that
           causes, you know, oscillations or causes you to
           accelerate your condensation as you go to saturation,
           which makes it hard to put numerics to solve.  In
           which case if it's a physical model, John will kick it
           back to me and we'll work together to try to make it
           more robust.  But, again, that's going to be a
           process.  It's going to be a process over a lifetime
           of the code.  But it is something we're committed to
           provide.  John?
                       MR. MAHAFTY:  Yes, this is John Mahafty
           from Penn State.
                       If I could make one comment on that.  You
           know, I've given guidelines to people at NRC and other
           places that if the time step gives 10-5, there's
           something wrong with the code, and I should see it. 
           If it runs for any significant period of time below
           10-4 there's something wrong with the code and I
           should see it.  So, you know, we're not taking the
           kinds of shortcuts -- that's a good term -- that were
           done in the past.  And I've seen problems where people
           have run RELAP5 and it grinds down and runs at 10-6
           seconds for long periods of time and finally it
           recovers and goes on.  That's not acceptable for us,
           because it tells you there's something wrong with the
           code, some kind of numerical problem is potentially
           masking what physically should be done and audited. 
           It needs to be looked at and it needs to be fixed.
                       MR. KELLY:  And I agree completely.  
                       The numerics can also effect accuracy, and
           there are a few things here.  In the future we'll be
           looking at higher order differencing in order to
           resolve things like thermal fronts.  As most of you
           know, the difference in the code at the moment is 
           first order accurate upland differencing so it tends
           to smear out sharp interfaces.  Thank will be future
           activity.  One that we have gotten created is level
           tracking.  And level tracking doesn't just mean, you
           know, we are a 2 face interface hits and where is this
           continuity of void fractions.  What it means is you
           find where that is and you go in and modify as part of
           the time step your mass energy and momentum
           conservation equations to take account of where that
           interface is on your computational grid.  And I'm
           going to show you an example in an oscillating
           manometer problem of why that's important.
                       In this last, we reimplemented semi-
           implicit scheming code which turned out to be very
           revealing in order for that we could do our stability
           calculations so that you don't get the damping that
           can develop in implicit scheming.
                       This is an oscillating manometer test
           problem.  Very simple.  Two vertical pipes, they're
           each 10 nodes one meter long.  And this is collapsed
           liquid level versus time.  The two pipes are joined at
           the bottom, they're open to the atmosphere at the top
           so it's an air-water simulation.  They were
           initialized half full at the 5 meter level with a
           velocity such that this should oscillate with an
           amplitude of 3 meters.
                       CHAIRMAN WALLIS:  No friction?
                       MS. UHLE:  No friction.
                       MR. KELLY:  No friction.  Water pressure
           is turned off.  Thank you.
                       Hence, we can tolerate it, but the orange
           curve is an analytical solution, and when this was cut
           and pasted from the frame maker document into
           PowerPoint the curves got kind of shaky.  But this is
           an analytical solution showing no dissipation. 
                       The black curve was the TRAC-M calculation
           with a standard curve. And after about two cycles it's
           totally damped out.  And the reason for that has to do
           with the discretization of the momentum-flux terms
           across that sharp interface.
                       CHAIRMAN WALLIS:  It's a numerical
           diffusion, in a way.
                       MR. KELLY:  Yes.  It's an artificial --
                       CHAIRMAN WALLIS:  Artificial --
                       MR. KELLY:  -- viscosity that wasn't
           intended, but because of the way the two phase
           momentum-flux changes.  When you correct that, and
           this was work done by Birol Aktas of ISL, this is what
           you get.  
                       Now, the test problem was changed slightly
                       CHAIRMAN WALLIS:  Are all those points on
           the curve, those are predictions?
                       MR. KELLY:  Yes.
                       CHAIRMAN WALLIS:  That there on a big Sine
           wave which is in length about ten times the --
                       MR. KELLY:  Okay.  The legend is missing
           here.  The upside down triangle is simply an
           identifier for the curve.  It's not a point.
                       CHAIRMAN WALLIS:  Oh.
                       MR. KELLY:  And likewise, so what you're
           seeing are two curves sitting right on top of each
           other.  And they're virtually indistinguishable, which
           is very nice that we can actually reproduce the
           innerlocal solution.  But not only that, we make the
           test problem a little bit more difficult.  It still is
           two pipes, but it's actually now six individual pipe
           components so that we could make sure that the level
           traction in steam could cross boundaries between pipes
           smoothly without putting any dissipation between that.
                       So, as far as the level tracking concern,
           there's no difference now between a no boundary in a
           pipe and a boundary between pipes.  And it's just part
           of the QA process to make sure the model works.
                       There have been a number of improvements
           to the --
                       CHAIRMAN WALLIS:  It seems to me there's
           a whole slew of these QA models you need to check, not
           just this one.
                       MR. KELLY:  Right.  And the more of that
           we can do the better.
                       CHAIRMAN WALLIS:  And I think it's been
           one of the concerns with all these codes that they're
           okay for nuclear safety, but they can't predict some
           of these very simple lab experiments.
                       MR. KELLY:  Yes.  I don't hold to that
           theory.  I think you have to predict the phenomena
           that are actually there.
                       CHAIRMAN WALLIS:  I think you should,
           right.  It's got to be honest.
                       MR. KELLY:  And that's going to be a
           process, and one of the most important parts of this
           program is going to be the assessment.  And that's got
           to be a continuing activity at a fairly high level for
           years, and just continue.
                       CHAIRMAN WALLIS:  I hope you keep doing it
           already.  Have been doing it.
                       MR. KELLY:  I'm not going to really talk
           about the improvements to the kinetic module.  That
           was pretty much gone over in Jennifer's presentation. 
           I simply don't have the moxy to do it.
                       MEMBER SCHROCK:  What did you do to the
           numerics again to change the picture so drastically?
                       MR. KELLY:  Okay.  If you get me off into
           details, I may have to go to Birol, but I think I can
           give you the idea.
                       MS. UHLE:  Birol left.  John Mahafty is
           his thesis advisor, he can answer the question.
                       MR. KELLY:  If you have an -- in the
           momentum-flux term there's an alpha row of DVDX.  How
           do you discrotize that term across an interface is the
           problem.  And if you look at the way it's typically
           done in RELAP or TRAC normally, it's really built into
           the two fluid model an assumption that you have these
           continuous evolution of weight fraction across the
           computational mesh.  And when you do that, that term
           is suitably accurate.  But if instead you actually
           have a sharp interface, so let's say you're on
           convection vapor out as this interface goes, but
           you're averaging between these cells to get these
           alpha rows and DVDXz then you introduce a dissipation
                       And I've actually even seen in some codes
           when it said dissipation, in fact sitation will reduce
           oscillation.  But normally it's dissipating.
                       So what we've done is say we have this
           tracking scheme that tells where this level is.  Now
           in our, you know -- we basically pull our back of the
           envelop and write down what the momentum equation
           should be if you've got the single phase vapor going
           across this with this level approaching it.  And then
           put in, adjust the terms in the momentum equation and
           make them what they really should be.
                       MEMBER SCHROCK:  But I thought there was
           already a level tracking in the original track.
                       MR. KELLY:  There was one in TRAC-B.
                       MEMBER SCHROCK:  Yes.
                       MR. KELLY:  And there was -- it works more
           as an interface sharpener.  So what it would do is try
           to track where the level is and adjust interfacial
           drag in an interfacial heat transfer model.  Level
           tracking has to, if it's going to work right, has to
           do a lot of things.  And so it basically it turns
           interfacial drag down.  It says, okay, there should be
           a level here.  Let's lessen interfacial drag so we
           don't pull this liquid up when we shouldn't be. 
           Likewise, it says okay the interfacial area is a pipe
           instead of treating the vapor as bolts.
                       But that's just really -- that's the easy
           part.  The tough part, which really gets this to work,
           is going in and actually fixing the conservation
           equation for a different physical situation.
                       CHAIRMAN WALLIS:  So this goes back to
           what I said this morning.  Jennifer was talking about
           a pipe.  You can recommend an equation for a pipe, and
           in fact they were this way, so that it behaves like a
                       MR. KELLY:  True.
                       CHAIRMAN WALLIS:  Under some circumstances
           because of the way you're averaging the stuff.
                       MR. KELLY:  You have to be very, very
           careful.  And this is something that Birol under
           John's guidance did a very good job on.
                       The last stage of the consolidation
           program is developmental assessment.  And what I've
           done is put together an assessment matrix that we're
           going to start to do during calendar year 2002.  I'm
           going to give you an example of how that was put
                       I also have a handout, I'll give you what
           I've proposed test matrix says.  I've got that written
           in, I'll get it to you.
                       Now, the test matrix is quite extensive,
           but it is far, far from comprehensive.  I mean, there
           are whole areas that are left out.  And those areas
           are going to have to be plugged by the assessment we
           do in the future.  And that's why Steve Bajorek is
           going to talk after me. 
                       We're going to a per face developmental
           assessment for each of the applications that the code
           is going to be used for.
                       So what I'm doing here is, remember our
           success criteria for the consolidation.  For the TRAC-
           M code we will be able to run it against each of the
           predecessor codes; TRAC-B, TRAC-P and the RELAP5 for
           the application of interest for each of those codes,
           and TRAC-M would do at least as well.  That's our
           success criteria.
                       CHAIRMAN WALLIS:  Do you have a matrix
           like this for simple experiments, like the manometer
           as well as these --
                       MR. KELLY:  Yes.
                       CHAIRMAN WALLIS:  -- messy experiments
           where everything's going on and you get AB
           compensating errors and so on?
                       MR. KELLY:  There's about half of those in
           the works.  And that's something that could be
                       This one is for separate tech specs
           reflood heat transfer.  And what I'm going to do is
           just give you an example of how this got made up.
                       The first thing I did was for the three
           predecessor codes; this was TRAC-M the F77 version,
           which is basically just TRAC-P.  There are no models
           in this version at all.  An assessment of that was
           done relatively recently, and that's the document
           NUREG/CR-6730, and that was published, I think, about
           a year ago.
                       For TRAC-B the last NUREG-B developmental
           assessment code was, i believe, the 3663, and after
           that there were two other NUREGs by other contractors
           that did further assessment of the TRAC-B code.  And
           I also had input from INEL and Penn State.
                       For RELAP5 this was the last published
           development assessment of the code, because there was
           also an assessment of it in this NUREG as well as the
           assessment we did for as part of the AP600.
                       So I looked at all of the tests that were
           done for these, and for this phenomena listed each of
           the ones according to the code it was used for.  And
           we then in the TRAC-M column, I basically summed them.
                       Now, if we simulated with one of the other
           codes, I brought it over and stuck it in here.  And so
           these are the ones we're going to do unless there was
           some reason not to do so, and that logic is what I'm
           going to show you now.
                       All of the codes the flux is at 31504;
           that's a one inch per second 40 psi base case force
           reflood test.  So, obviously, we're going to do that.
                       31701 is 6 inches a second, so that's at
           the other end of the spectrum, so that was done in
           RELAP5 and we will include that here.
                       Now, this test 33436 is a gravity reflood
           test done in FLECHT SEASET, and because of the way the
           downcomer is and the way the exit coming up the front
           is there are a lot of uncertainties in the downward
           positions.  So there's no good reason to do a gravity
           reflood simulation for that facility when we have
           facilities like CCTF and SCTF.  So I'm going to
           eliminate this test.
                       Now, when I looked at -- I just mentioned
           CCTF.  As part of the TRAC-B assessment measure there
           was a CCTF basis run in 14.  But what they did is
           actually a gravity test, but they ran it as a forced
           reflood test.  What that means is they stripped off
           the downcomer, stripped off the wall clamp and imposed
           a flooding rate at the bottom of the core.  That's
           artificial.  No one knows what that flooding rate is. 
           They inferred it, it was inferred from the
           experimental data based upon what came out the top of
           the bundle and the build up of inventory in the
                       So running this as a forced test -- I mean
           if you're not even monitoring what you're putting into
           the bundle right, how can you do an assessment of it. 
           So I think this is of limited value and as part of the
           integral effects testing we will be doing a couple of
           CCTF cases.  That's something in the future we'll have
           to expand.  I saw no point in doing this, so I took it
                       FLECHT SEASET there was one test run for
           TRAC-B, and obviously we're going to keep this.  This
           is a large scale reflood  gravity.  It's 8 bundles,
           2,000 meter rods lined up in a slab, so it models at
           full scale the distance between the reactor core
           center line and the core barrel.  Very important
           contributing effects.  The Lehigh Rod Bundle, this was
           done with TRAC. It's a nine live bundle, so it's 3 by
           3, which means it's about this big, and there's a
           heated shroud there's a lot of questions in its regard
           to things like heat losses, its quality fully
           instrumented and plus as you know, if you try to do a
           two phrase, and this is also in one atmosphere, test
           in something this big, any vapor structure is going to
           span it and it's going to act not like a broad bundle
           at all, but more like a tube.  So it's not productive,
           its of limited usefulness, let's not waste our time on
                 FLECHT test 9077 which was done on TRAC-B, is
           from the original FLECHT series and it's 6 inch per
           second new core rate capacity.  Now that facility does
           not have delta P cells, and likewise did not measure
           specifically the steam temperatures.  There is a lot
           in that less experimental information than there is
           with the more modern codes like FLECHT SEASET.  So I'm
           going to get rid of this test and replace it with
                       The GOTA, and I know I don't pronounce
           that right, but this reflood test is combined top
           spray cooling and bottom reflooding.  Well if we're
           going to discuss the BWRs you need to have assessment
           cases for that, so we've got to keep this.  
                       The NEPTUN facility which was done in
           Switzerland is 33 rods of half height. Now, again, 33
           rods as counted as 6 by 6 with the corners taken off,
           is relatively small.
                       The two tests that were done, one was at
           one 1« centimeters and one was at 15 centimeters a
           second.  So what I've done is instead of doing these
           two tests, I'm going to substitute the FLECHT SEASET
           test run.  This one is 6 inches a second.  I added
           this test, which is 34006, which is 0.6 inches a
           second to compensate for the NEPTUN test that I'm
           going to drop out.  So what I'm trying to do is to
           come up with a test basis that makes sense and covers
           the range of conditions that we have been testing
                       CHAIRMAN WALLIS:  Of course, the advantage
           of something like NEPTUN in is that it's not -- your
           conclusions are not test dependent so much on FLECHT. 
           You can say you've got something independent, you're
           able to predict.  And if there's something wrong with
           the modeling because of the geometry of NEPTUN, maybe
           that means that something should be in the code
           anyway.  So you might see if you can get a more
           diversity, perhaps, in the sources of the experiments.
                       MR. KELLY:  What we will be doing --
           remember, these are -- we will be doing in the future,
           okay.  We're going to expand the matrix both in the
           CCTF and SCTF, and this is something that Steve is
           going to talk about.  There are actually forced
           reflood tests in SCTF, which are of great value
           because then you know actually what you're showing in. 
           You don't have the complications of, you know,
           potential oscillation and some down time.
                       CHAIRMAN WALLIS:  You've got to prepare
           NEPTUN.  When you sort of release the code somebody
           else may, and you might want to do it ahead of time.
                       MR. KELLY:  The problem is there's a lot
           of data out there and we have to just do the best we
                       MS. UHLE:  Our international partners
           have, especially Switzerland with respect to NEPTUN,
           are interested in doing assessment for us.  And that's
           what helps us get, you know, broadening our assessment
           range.  And so I think that first to meet the 2002
           deadline, we are trying to make one that, you know,
           take some consideration with the good data that's out
           there and then in the future, with the fact that we
           have the PM program, that really broadens out our
           assessment on this.
                       MR. BAJOREK:  We would welcome other
           groups coming in, any additional tests that would have
           matrix.  One of our problems has been resources and
           trying to pick the test step that will give us the
           most information without letting the matrix get to out
           of hand.
                       MR. KELLY:  And I'll give you a copy of
           the proposed matrix as soon as I get off the stage
                       That ended the part the presentation on
           the status of the code consolidation.  And we're going
           to skip over the presentation on the SNAP, and what
           I'm going to jump into now is instead the code
           development effort for the future.
                       Again, when we first started this project
           we went out and queried our users, both internal and
           that would have been NRR and was then a ADOD, as well
           as PT and RAS.  And our external users liked, you
           know, he said, if we're going to have a state of the
           art thermal-hydraulics code, what should it have in
           it? And this is the laundry list they came up with.
                       In items number 1 was an improved user
           interface.  And that part of the reason why we're
           putting in the effort on this now, to make the code
           easier to use.
                       I'm not going to go through all of these,
           but I'm going to do instead --
                       CHAIRMAN WALLIS:  Well, where there's a
           gap, does that mean you're not doing it at all?
                       MR. KELLY:  No.  It means that that it
           hasn't started. 
                       And what I'm going to show you now --
                       CHAIRMAN WALLIS:  You're not using modern
           numerical method?
                       MR. KELLY:  Well, that means that
           developmental efforts incorporate, for example, either
           higher order differencing or a more fully implicit
           scheme has not started.  And for what I'm going to
           show you, again the colors are abominable on the
           viewgraph. I don't know what it worked out that way,
           but --
                       MS. UHLE:  They're extraordinary.
                       MR. KELLY:  To say the least.  This is our
           plan for what we're going to do next year and the in
           the future.
                       So, up to here is the conclusion of our
           current five year plan.  From this line on is the
                       Now, I've broken this down into these
           categories:  Consolidation and assessment; physical
           models; numerics improvements; modeling capabilities;
           and, then along the bottom I've shown code release
           dates.  And this Rev zero will be the first release of
           the consolidated code, and that is at the end of 2002. 
           And what we're planning is annually at the end of each
           calendar year to release another revision to the code.
                       And now let me explain this a little. If
           you could see the colors, there's a color code here.
           This is supposed to be a light blue.  You notice these
           boxes go with this code release.  So these activities
           will be finished and go into this code release.
                       Likewise, the green boxes feed into this
                       CHAIRMAN WALLIS:  You must have had a
           color consultant or something.
                       MR. KELLY:  Well, apparently I didn't have
           a very good one.  A budget decrease.  
                       And so forth. And then actually this is
           revisions 3 through 5.  I didn't -- once we get out
           this far in the future I don't know exactly what we're
           going to be doing when.
                       CHAIRMAN WALLIS:  Why didn't you use the
           primary colors?
                       MEMBER SCHROCK:  If you put actual dates
           in there, whatever they're going to be,  0.0 is
           October 1, 2002.
                       MR. KELLY:  No, these are the calendar
                       MEMBER SCHROCK:  Calendar year.
                       MR. KELLY:  Yes.
                       MEMBER SCHROCK:  So that means January 1,
                       MR. KELLY:  Exactly. That'll be the first
           release of the consolidated code.
                       MEMBER SCHROCK:  So that's 13 months away
           and you don't have a document that describes the code
           in any complete way today. You intend to have one
           prior to that and have some feedback as to how good it
                       MS. UHLE:  You want me to answer?
                       MR. KELLY:  Please.
                       MS. UHLE:  We have -- I mean, because we
           started from a TRAC-P code, we have the base TRAC-P
           theory manual.  And in-house we're going through that,
           Frank Odar, Jim Han and they're pointing out where
           things are confusing.  With the developmental work
           that has been going on we follow S2A procedures.  And
           when it involves physical modeling, of course, there
           are sections written by the developers documenting
           what was done so that those sections will be put into
           the theory manual.  So we have the documentation.  It
           has to be merged and it has to, again, get another
           read through to make sure that there are --
                       MEMBER SCHROCK:  I guess what I'm asking
           is are you going to release this whether the
           documentation has been reviewed or not?
                       MS. UHLE:  No, no, no.  We will have the
           documentation released with in-house review and if
           you're offering review from the ACRS if that's what
           you're offering.  But, yes, I mean we realize that
           it's fast approaching.  But I don't want you to think
           that there is no documentation.
                       If you go up to the consolidation room,
           there's documentation like up to here. It's a matter
           of going through, organizing it and putting it into
           the master document.  Now everything is written in the
           same way, word processor format, so that's going to
           facilitate things.  And then we're starting to begin
           the merging.
                       The user manual is up to date.  We have to
           put in modeling approaches on how to model the BWR,
           but we're going to take out of the TRAC-B and, again,
           go through read through and add to it as necessary. 
           But the user guide is the one that's in the best
           shape, and the theory manual is our one that --
           especially during the developmental assessment and we
           start to replace physical models, we'll be adding to
                       The programmer's guide talking about the
           architecture of the code, we have made revisions to
           that with the modernization, but that one is the one
           that's lagging the most, although because we're
           focusing on making this code more maintainable that is
           something that we will have to do.
                       MR. BOEHNERT:  Does the master document
           include those three things you just mentioned?
                       MS. UHLE:  No.  There's a theory manual,
           that is a master document.  There's a user guide, that
           is a master document.  
                       MR. BOEHNERT:  So each one -- okay.
                       MS. UHLE:  But, again, if you're
           interested in looking at what we've generated so far
           and reviewing it, then we would be, I would think,
           more than willing.  Although I don't know, I'm not the
           office director.
                       MR. KELLY:  Thank you, Jennifer.
                       CHAIRMAN WALLIS:  Is this thing suitable
           for any two phase flow problem?  I mean, it doesn't
           have to be nuclear reactors, does it?
                       MR. KELLY:  Well, you can keep the
           components of a couple of different pieces.
                       CHAIRMAN WALLIS:  I think it would add a
           tremendous amount of credibility if it was something
           like the commercial code which is out there and has
           been proved to work for oil and gas, and chemical
           plants and all kinds of things.   If it works for all
           these other areas as well, then it must be really
           good. When it's only been shown for a couple of
           nuclear applications, then it looks real suspicious.
                       MS. UHLE:  We are getting requests for the
           code for the oil industry.  And also heat exchanger.
                       CHAIRMAN WALLIS:  It would be very nice if
           you could in some of these presentations, particularly
           the public presentations show that it's not just been
           tuned to some nuclear applications.  Okay.
                       MR. KELLY:  For the consolidated code,
           what is going to show up is what we've talked about
           before, finishing the way to translate RELAP through
           SNAP to be able to run it in TRAC-M, the developmental
           assessment and then there's the two model changes, the
           bundle interfacial drag, which is an implementation of
           the TRAC-B and the interim reflood model, which I'm
           working on.  And then we are going to do some work in
           the beginning of the year on robustness.
                       And one of the things I tried when I set
           this up was have development activities in
           approximately in mid-year so that we would have a
           frozen type version for, hopefully, as much as six
           months to go through the testing before you get to the
           release date.  So that on December 31st we're not
           changing the code model of a code that we're going to
           release January 1.
                       Probably one of the most important
           activities here is the PIRT based assessment which I
           show across the top.  And that's what Steve is going
           to talk about.  And it can be this assessment where
           you look at the important phenomena and see how well
           the code does against them that then will drive what
           we do here.
                       The only other thing I want to talk about
           is some of the model development from out experimental
           programs.  The green box here is supposedly subcool
           boiling, and that refers to the UCLA program on
           subcool boiling and low pressure. We're going to
           receive a model approximately mid-year and we'll be
           implementing it during the end of 2002.  But because
           it's going to come in at the end of year, I don't want
           it in the release code version because we want in for
           suitable testing.  So it will be part of the Rev 1.0
                       This box is phase separation and this is
           to build on the experimental work at OSU.  So when
           we're able to get a model from them that we have
           confidence in we'll be putting in the code, hopefully,
           in early to mid-2003 to show up in the Rev 1.0 code.
                       The other one is  -- it really should be
           more mechanistic but obviously we're not thinking we
           put first principles, but more mechanistic than
           certainly what we have today.  And that's going to
           build on the external information from rod bundle heat
           transfer facility at Penn State.  And I have several
           slides on that later.
                       These tests are not yet defined, but I
           have an idea of what's going to go in them.  And those
           actually take the next few slides. I'm not going to go
           over those in detail, but this is what we anticipate
           as of today that we're going to have change in the
           code to make it really do a good job on more and more
           reactors.  Core spray model, boiling transition.  For
           example, the model incurred is normally the OXY
           correlation, which is basically the annular pore
           regime in tubes.  Obviously that does not give a very
           good representation of dry auditing of water reacting
           models, but also putting the place in the code that
           supports, if you will, where a user in NRR or actually
           at the request of NLR can incorporate on a temporary
           basis a proprietary model in order to help them
           facilitate their review.  You have to adjust modern
           fuel designs and fuel designs.  And obviously, as I'll
           show you, the reflood model needs a lot of work.  That
           applies to more and more reactors as well as to
           pressurized water reactors.  And also we'll have to
           look a little more at top-down rewet both on the
           channel box and the fuel lines.
                       MEMBER SCHROCK:  This item on the BWRs
           incorporated the proprietary model, you have in mind
           something like what GE says they have for their rod
           bundle on the first principle.
                       MR. KELLY:  I assume what you mean is
           where they have a drop of pH and look at the stripping
           of the drops and the deposition of the drops
           downstream of the grid.  That's not what I meant. 
           What I meant here was the better correlation.  Like,
           for example, I'm looking at pressurized water
           reactors.  Each vendor of each fuel design goes
           through a testing program and develops and in effect
           licenses the correlation for that particular type of
           fuel.  And then if you go and do some kind of
           operational transient where your success criteria is
           DMBR margin, well if you forget to write thermal-
           hydraulic conditions versus time, but you want to
           check the margin, you need to have an actual
           correlation for the BMBR that suits that fuel
           geometry.  And it even depends upon all the little
           tabs on the rib spacer, and it's somewhat analogous
           for boiling-water reactors.
                       MEMBER SCHROCK:  Well, here's you're
           talking about boiling-water reactors.
                       MR. KELLY:  Right, that's true.  
                       MS. UHLE:  Can you do a Drexal
                       MR. KELLY:  Well, what I'm talking about
           is more like that.
                       MEMBER SCHROCK:  That's what I'm talking
                       MR. KELLY:  Not going to actually trying
           to predict it by stripping the film off the rods and
           then depositing the drops downstream; that would be a
           research project.
                       CHAIRMAN WALLIS:  Joe, you are half way
           through your slides and taken about the time that was
                       MR. KELLY:  Really?  I thought this was
           going pretty fast.  Okay.
                       MEMBER SCHROCK:  One last simple question. 
           Do you envision this option to incorporate the
           proprietary model as something to be used by industry
           in their use of the code or something you would do
           with your code?
                       MR. KELLY:  I envision it as something
           that we would do in order to facilitate doing our in-
           house calculations.  But it would be something that
           other people could use to more easily implement.
                       MEMBER SCHROCK:  Yes.
                       MR. KELLY:  And this is, you know, just
           what we would like to do.
                       MR. BOEHNERT:  Well, I don't know how you
           get around, though, the thing that these codes are
           supposed to be publicly available.  I mean, that's --
                       MR. KELLY:  That's why we're not going to
           build it into the code.
                       MR. BOEHNERT:  Yes, I understand.
                       MR. KELLY:  Just a box, you code it
                       MR. BOEHNERT:  Yes, a black box you put it
           in.  Yes. Okay.
                       MR. KELLY:  Similarly, I've looked at, you
           know, based on what we've done in the past, we looked
           at small break LOCA, what were the problem areas.  And
           we made up a laundry list of where I think once we
           really start doing the PIRT based PA we're going to
           have problems.  And this is the list, and in the
           essence of time, I won't go through the list.
                       I have a similar one for large break LOCA. 
           And that takes me to what we're doing now, which is
           the current model development activities.  And there
           are two, as I've mentioned.  The first is not model
           development so much as it model implementation, so
           it's a rod bundle on interfacial drag, boundaries
           necessary for the Peach Bottom Turbine Trip benchmark. 
           What we're going to do is implement the TRAC-B
           interfacial drag and interfacial heat transfer models
           all in route for the CHAN which is a BWR fuel
           assembly.  And we're going to look at applying it to
           the core region of the 3-D vessel.  Because,
           obviously, the interfacial drag per bundle is better
           than the correlations we have at the moment, which
           were mainly focused for 2-D.  And it'll just be
           implementing them at what I call low-level
           modularization. This is an in-house effort by Joe
           Staudenmeier and Tony Ullses.
                       The development activity is to come up
           with an interim reflood model, and it's necessary for
           doing realistic auditing calculations for the AP1000. 
           The reason it's necessary is the current model has
           unacceptably large oscillations and at least for
           separate FLECHTs tests it's highly conservative.  I'll
           briefly show you the results of one of those.
                       We have to look at two things; the
           physical models and also the fine-mesh numerical
           scheme, and also is an in-house effort with Weidong
           Wang and myself.
                       I'm going to skip the fine-mesh rezoning
           scheme, just in the interest of time, unless there are
           questions about it.
                       So I'm going to skip over the next two
                       MEMBER SCHROCK:  You never question the
           adequacy of flow regime maps in the code.
                       MR. KELLY:  Well, I do.  Do you mean the
           idea of using flow regimes in general or the ones in
           the code in particular?
                       MEMBER SCHROCK:  Well, I mean the ones in
           the code in particular.
                       MR. KELLY:  Yes.  I mean, certainly
           something that's based on a one inch diameter air-
           water atmospheric pressure is not anything close to
           what, you know, we should be having in reality.  And
           that's something we have to look at.  There's lots of
           areas of physical models --
                       MEMBER SCHROCK:  But it isn't going to be
           a part of the TRAC-M development?
                       MR. KELLY:  Not part of the development to
           be released at the end of December 2002.  In my
                       MEMBER SCHROCK:  So you think it will be
                       MR. KELLY:  Yes.
                       MEMBER SCHROCK:  Okay.
                       MR. KELLY:  I'm pretty sure.  There was an
           item on here for low pressure interfacial drag that I
           didn't talk about, and we're pretty sure that once we
           start doing things like AP1000 and low pressure EKD
           models that we're going to over predict interfacial
           drag.  And that's a point where we revisit the bundle
           interfacial drag model and try to establish a database
           and maybe come up with a new model if we can't find or
           develop one that is accurate enough.
                       The whole idea of replacing flow regimes
           is out here much later in time, and that's the
           interfacial area transport work.  
                       But speaking of flow regimes, there are a
           number of idealized points in reflood.  And what I'm
           showing here is clad temperature versus time of 1 inch
           porous reflood case, and this is the heat transfer
           coefficient versus time.   And so at any one point you
           do through a progressional regime starting with steam
           cooling.  The steam cooling actually probably stopped
           here, and this is when the dispersed flow film boiling
           started.  The dispersed flow film boiling started as
           the most important regime simply because that's the
           point in which the turnaround in the clad temperature
           established a peak value.  So you always think you
           need to model this very well.  However, there's
           another regime just a little up stream of it which
           I've labeled the froth region here.  And in the future
           you'll hear me talk about invert slug, invert annular,
           those types of things.
                       This region could be anything from a few
           inches to a couple of feet, depending on the flooding
           rate and liquid subcooling. It's very important from
           the standpoint that with this cooling that brings the
           clad temperature down to your quench, the temperature
           at which the rods get wet.  So not only does it
           control the propagation of the quench time, but it's
           again that the vapor generation in this area and at
           the quench time provide the source term for vapor flow
           and entrainment that you have in the dispersement
                       Currently in TRAC-P -- this is from the
           manual, this is the reflood heat transfer coefficient
           module.  And I don't expect you to be able to read
           that from this, but it's okay.  
                       This is an imagine the idealized flow
           regimes when we go from transition boiling, smooth
           inverted annular, rough wavy, agitated inverted
           annular, dispersed flow, highly dispersed.  In all
           these different regimes, you go through the code and
           you use a weighted sum of contribution to each regime. 
           So what you have is one model turning on, ramping off
           and another model turning on and ramping off and so
           on, and you add all these pieces together.  Well, it's
           highly confusing, it's also very complicated.
                       CHAIRMAN WALLIS:  That is the problem in
           using a high pressure syllabus. I couldn't read it, so
           I thought the flow was coming from the right.
                       MR. KELLY:  That's hysterical --
                       CHAIRMAN WALLIS:  You're going through
           bubbly and slug and annular.
                       MR. KELLY:  But worse, you know it's bad
           that it's so highly complicated. But what's worse is
           that it's poorly suited for inclusion in the
           computational model.  I'll briefly tell you what I
           mean.  Each of these regimes is characterized by a
           link and that link is a function of capillary number. 
           So this is based upon the type of break-up you get if
           you take your garden hose out and turn it upside down
           and have a jet coming down, when that jet breaks up. 
           So each of these links is a function of the liquid
           velocity, at the quench front.  And any of you that
           have ever worked at code calculations you know how
           noisy that is.
                       So what that says is the length of each of
           these regimes that's been used oscillates with the
           liquid with velocity.  So, in effect, this type of
           scheme amplifies any numerical noise whatsoever.  And
           in practice, for a forced reflooding case it leads to
           very large oscillation that throws most of the liquid
           out of the bottle.
                       MEMBER SCHROCK:  I mean this view of
           physics ignores the fact that when you look at such
           experiments you actually see some large masses of
           liquid that get thrown up and then they fall back. So
           at any given instant what's happening at some point 
           above quench front is some liquid going down, some
           going up and some hitting each other, of course some
           not and net flows.  There are aspects of the physics
           that are not recognized in this view point.
                       MR. KELLY:  And there are aspects that we
           will never capture, even if we implemented second
           liquid fuels so you can have some going up and some
           down.  Because we'll always end up having to treat it
           in a time average sense. You know, averaging over some
           suitable period which may be on the order of seconds. 
           But that's --
                       MEMBER SCHROCK:  Well, this is a very
           fundamental issue with regard to these equations
           altogether.  You have variables which are presumably
           space and time averaged.  No attention given to what
           that really has to mean in terms of specific parts of
           the two phased domain, where in fact the time scaled
           at which you have to be doing the averaging is pretty
           long.  It's a little bit of a stretch to imagine that
           you really have meaningful time smooth variables that
           you can work with the same sense that you do, for
           example, in single turbine and single phased flow.
                       MR. KELLY:  That's a limitation that, you
           know --
                       CHAIRMAN WALLIS:  This is the present
           state of the arch you put up there and they're going
           to improve it.
                       MR. KELLY:  Well, the first thing I want
           to simplify it and come up with the energy and
           hopefully, the plan then is to use the theta from the
           RBHT facility to come up with a more mechanistic
           model.  But to go to the one more detail that
           Professor Schrock is, that's really out there,
           especially in a computational framework where you're
           talking of modeling the power output.
                       And as a result, this shows an example. 
           This is FLECHT-SEASET 31504 which is the rate
           excessive force flooding case.  Clad temperature
           versus time, this is just above the core mid-plane. 
           This is the data from three different thermal couples,
           and this is the current TRAC calculation.  And you
           notice this is more than 300 degrees K, and this would
           be completely --
                       MEMBER SCHROCK:  Well, it's conservative.
                       MR. KELLY:  It's highly conservative.
                       MS. UHLE:  Extraordinarily.
                       MR. KELLY:  At least for a forced flooding
           case and that's because there are in effect these
           vapor explosions, if you will, which throw most of the
           liquid from the bundle out the top and FLECHT-SEASET,
           you know, can point to that as a phase separator so
           the water can't come back down.  So a one inch per
           second case ends up being like a one-tenth of a second
           case which with that flow rate we have a very hard
           time turning the temperature around.
                       CHAIRMAN WALLIS:  It's pretty good to be
           up at 1400 degrees Fahrenheit.
                       MR. KELLY:  So, obviously, we have some
           work.  This is why we're doing the work, while we try
           to apply this to AP1000.  And so, obviously,
           improvements need to be, we have to reduce the
           oscillatory behavior and improve the accuracy of the
           prediction.  And I'm going to try to do that with
           using a simple modeling first, and wherever I can use
           bundle data, sometimes tube data to come up with a
           simple way of doing this and one that is less
           suspectable to oscillation.
                       I'm now on the last page of my talk and,
           hopefully, this is practically finished.
                       CHAIRMAN WALLIS:  Well, you've had your
                       MR. KELLY:  Yes, I'm afraid so.
                       And I'm going to talk about incorporation
           of experimental results, and hopefully very briefly.
                       And I've got a little note here, the ACRS
           role is I think that would be very good.  As we do
           these experimental programs and these are our
           contractors who are asked to develop models from them,
           it would definitely help us to come in front of you,
           present those models and get your opinion.  And in
           effect, for us to have a peer review via you of how
           good those models are before they get, you know,
           encapsulated in concrete.  So this is certainly an
           area where I think you could help us.  You know, as
           kind of as unpaid consultants.
                       We currently have four experimental
           programs.  Low pressure, subcooled boiling at UCLA,
           phase separation at OSU, which you already know about
           since it's been out there, the rod bundle heat
           transfer programs at Penn State, and the interfacial
           area transport at Purdue and the University of
                       This general program will be finishing in
           the middle of the year.  The model will be delivered
           and they will be implementing the code late 2002.
                       Phase separation, hopefully that in 2003.
                       The rod bundle heat transfer, this is one
           I want to talk a little bit more about.  It's designed
           to provide detailed measurements for model
           development.  It's not simply let's get some more
           reflood data, because there's a lot of reflood tests
           out here.  But there was a lot of thought in how to
           try to instrument the bundle and what development
           information we need.  And that's the example that I'm
           going to use on the incorporation of experimental
                       The reflood tests will be conducted in
           mid-2002.  There will be 15 of them, roughly 12 or 13
           will be for model development.  There will be no
           constant flooding rate for test cases to look at one
           particular regime.
                       There will also be 2 or 3 variable
           flooding rate cases which we'll use for code
                       But we're also going to use steam cooling
           and drop injection tests, and I'll talk about those in
           a little bit.  And those will be in late 2002.  Then
           the data analysis and model development will be in
           2003/2004.  And at that point we'll have low
           mechanistic reflood model in the code to do that.
                       The interfacial area transport, this
           should be viewed as a long term exploratory research
           program and the idea is to try to move the level of
           the physical models one step closer to something
           mechanistic where you're now looking at pebble
           coalescence and breakup instead of the static flow
           regime model.  And so we're due to implement this
           model in 2005, however the data is being generated now
           we'll be able to use as part of PIRT assessment
                       And the key thing on this slide is as
           these programs end, we hope to start other
           experimental programs to take their place so we keep
           the level of thermal-hydraulic experiments that we're
           funding more or less constant in time instead of
           on/off.  But replacements to these experiment programs
           will come about from code assessment results.  We
           identify a deficiency in the code in an important
           element, can't find the data in the extent database
           and get a targeted date, then we'll identify an
           experimental program and try to get one started.
                       So this is the example of how to
           incorporate the experimental results.  At least the
           beginning of that.  What I'm going to talk about is
           the dispersed flow film boiling agent, which is the
           one that we think of as the most important in terms of
           the large break LOCA because that's where you turn
           around the clad temperature.
                       In this regime the most important heat
           transfer mechanism is forced convection from the rods
           into the vapor.  To the superheated vapor.  But there
           are two major unknowns.  One is the drop diameter,
           which is a rather fundamental quantity and the other
           is two-phase convective enhancement.
                       The drop diameter is primarily important
           because of its effect on the vapor superheat.  I mean,
           after all, that's your sink temperature.  You're
           transferring heat via conduction through the steam to
           a highly superheated steam.  So what that temperature
           is is very important.
                       However, it also effects drop breakup on
           the grids, the two-phase convective enhancement, as
           well as the wall-drop radiation heat transfer.
                       In reflood the drop formation mechanism is
           not known, and every paper you read says something
           different.  Is it aerodynamic breakup of liquid slugs,
           or a breakup of an actual inverted annular column. 
           Sometimes it may be one, sometimes another.
                       There could also be wave entrainment
           either from waves on an inverted annular core or if
           you're in a low flooding rate case where you actually
           have annular core below the quench front it can be
           waves on that film.
                       You can also have wall to drop
           interactions.  A drop can collide with the wall and
           bounce off and shatter, or it can collide with the
           wall and in effect be blown off by rapid boil, and
           that can shatter the drop.
                       Which of these mechanisms or how these
           mechanisms interact to control an average effective
           drop size is really unknown.
                       CHAIRMAN WALLIS:  These are all
           speculations or fantasy, you mean?
                       MR. KELLY:  Yes.
                       CHAIRMAN WALLIS:  They're not based on
                       MR. KELLY:  Well, some of them are.
                       CHAIRMAN WALLIS:  They are?
                       MR. KELLY:  Yes.  Depending upon which
           paper you read, various people say different things.
                       CHAIRMAN WALLIS:  Is that because they've
           actually seen it or they've speculated it?
                       MR. KELLY:  Well, some of it is seen.  For
           example, the annular film and waves on the annular
           film comes from a British paper reflood in, I believe
           it was a quartz tube.
                       The breakup of liquid slugs, I don't
           really remember.  
                       But, you know, I've been through a lot of
           references and you see a lot of different things.
                       Two-phase convective enhancement, what
           this is, you know, we know that the core's conduction
           is steam.  But if you have a dispersed phase, whether
           it happened to be solid particles or drops, that will
           effect the heat transfer rate.  And now especially in
           the case of drops, the act is heat sink, so vapor
           sources -- preliminary estimates of data say that this
           should enhance your flows convection heat transfer by
           20 to 100 percent.  But, again, the controlling
           phenomena is not known.  Is it via turbulent
                       We know from like, you know, grasped
           particles in air if the particles are very small, in
           the order of 30 microns or so, they do tend to excite
           the turbulence and increase the heat transfer.  If
           those particles go up to about 100 microns, they damp
           the turbulence and decrease the heat transfer.
                       Our drops tend to be more like 1,000
           microns.  So how do they interact with the turbulence? 
           But, of course, there's not one drop size anyway. 
           There's a spectrum of drop sizes.  Some might enhance
           the turbulence, some might dampen it.  But once you
           get up to a millimeter and larger drops, now you've
           got drops with significant weight regions which could
           generate more turbulence because of that.
                       Likewise, if you have all these drops
           distributed in this hot steam, you change the
           temperature profile of the steam.
                       CHAIRMAN WALLIS:  It's dispersed flow
           boiling, it's not film boiling.  There is no film. 
           It's dispersed flow boiling.
                       MR. KELLY:  That's true.  That's, you
           know, just the way it's been.  And what we're trying
           to say is that the surface is dry.
                       CHAIRMAN WALLIS:  Yes, but what I think
           what they mean is the surface is dry.
                       MR. KELLY:  Right.  That's what the film
           in that context means.  If you will, a vapor film.
                       So those are two of the most important
           things or us to look at.  And how are we going to do
           that with the rod bundle heat transfer facility. 
           Let's talk about drop diameter first.  
                       And what I've done is basically put up all
           of the drop diameter data that I could find in the
           open literature, and this drop diameter data from a
           reflood test.  And, as you know, there's tons of data
           for primarily air, water and tube annular mist flow,
           but even if you go from one of those papers to the
           other, what the correlations for drop diameter are are
           different; there are dependencies on physical
           properties or even the vapor momentum flux are
                       So what I've applied are sauter mean
           diameter versus pressure reported in a test.  ACHILLES
           and FLECHT-SEASET are actually bundle reflood tests. 
           This is the FLECHT-SEASET data all run at about 40
           psi.  I spread it out in pressure just so you could
           see the points, but they're actually all at the same
           pressure or almost the same pressure.
                       These are from a -- high speed group from
           several -- about  half a dozen different reflood
           tests, different flooding rates and so on.  It's
           actually pretty amazing that the sauter mean diameter
           is as constant as it is, just a little above one
                       CHAIRMAN WALLIS:  Six millimeter is a
           humongous drop.
                       MR. KELLY:  Yes, that's a problem, too. 
           And what you have then is water plugging the tube, and
           that's why the drop can be carried up.  It's the
           container wall effect otherwise for those cases the
           vapor velocity would be low enough you couldn't carry
           the drop up.
                       CHAIRMAN WALLIS:  Even one millimeter
           seems pretty big.
                       MR. KELLY:  I agree, especially if you
           look at a rod bundle with the grid space, and you go
           how can a poor little drop get through.
                       The ACHILLES tests, those were actually
           from two different reflood tests, but the distribution
           isn't --
                       CHAIRMAN WALLIS:  So mean diameter, that's
           a mean diameter of 6 millimeter.  It must mean some of
           them are two centimeters.  That's crazy.
                       MR. KELLY:  Well, it can't be bigger than
           the tube.  I agree, those are huge.
                       These tests, these are rod bundles, these
           are tubes.  This Hall & Ardron, this was done at CEGB
           I think in the early '80s, I don't remember.  This was
           done at University of California Berkeley by Seban et
                       This is reflooding --
                       CHAIRMAN WALLIS:  Before they married to
           one another.
                       MR. KELLY:  It's hard to know which of
           these to believe.  But it would appear --
                       MEMBER SCHROCK:  This kind of statement
           bothers me, it's hard to know which of these to
           believe.  These experimentalists are presenting data
           from different kinds of experiments and why do you
           think that as a code developer you're going to
           evaluate which among these that had maybe different
           objectives even, is right or wrong?  I wouldn't begin
           by assuming some are right and some are wrong.  I'd
           begin by trying to understand why is there this kind
           of apparent discrepancy that arises out of these
           different kinds of experiments and how does it relate
           to the simple or the actual system that I'm trying to
           model with this code.
                       MR. KELLY:  No.  That's a very good point. 
           Both of these were tube tests, but one was a quartz
           tube, one was a, I don't know if you know the CRE
           valve.  They were both basically the same kind of
           traditions opposed to directed methods of tube
                       MEMBER SCHROCK:  If you get into details
           of the paper, you'll see that the credibility of the
           meaning of a sauter mean diameter for some experiments
           may be better than, you know, some other experiments.
                       MR. KELLY:  Depending on the sample size,
           that's exactly correct.  And what I probably
           misstated, mispoke a little -- what I should say is
           this isn't solely a function of pressure.  And what
           you may very well be seeing here, rather than one
           being right and one being wrong, there may be at
           different values of the vapor momentum flux, and that
           may explain the large discrepancy.  But from
           everything I've seen so far, is the vapor momentum
           flux goes up, the drop diameter goes down.
                       CHAIRMAN WALLIS:  I guess the message I
           get is that you're looking at all these things, you're
           trying to figure out the reasons for discrepancies and
           do better at it.
                       MR. KELLY:  Right.
                       CHAIRMAN WALLIS:  At the level we're at
           today, we can't get into the details.
                       MR. KELLY:  Right.  Most of the current
           models that people tend to use in codes are simple
           functions of the LaFosse number.  So it's a function
           of pressure only.
                       CHAIRMAN WALLIS:  LaFosse with gravity in
                       MR. KELLY:  Sigma over G delta rho
                       CHAIRMAN WALLIS:  Does gravity have
           anything to do with the phenomena that's happening
                       MR. KELLY:  Well, what they're saying is
           that you can only -- if you're given vapor flow, you
           can only get up to a certain size drop, and less, then
           use a critical web number of criteria for what that
           size will be equated to and you come out with that. 
           And that's roughly how you come up with that.  And
           that will give you the maximum size drop, then you
           have to make some assumption to get from that to a
           sauter mean, typically a factor of 3 or so, but you
           know what exactly it is is hard to define.  But it
           looks like there's a pressure relation here, but that
           could be some other reason.
                       CHAIRMAN WALLIS:  If you did the
           experiment in a space shuttle, the drops would have
           zero diameter is that what you mean?
                       MR. KELLY:  No, because then you would
           have to have different non-emitional groups because
           you have a different control element.
                       CHAIRMAN WALLIS:  Okay.  I understand.
                       MR. KELLY:  And as I recall, you'd tend to
           get really large drops.
                       So anyway, that's the data that's there,
           but that is certainly not sufficient to develop to a
           correlation level.  And the real reason it isn't is
           because the data base lacks the information on the
           flow conditions and we don't know what the vapor
           velocity is.  We don't know the vapor density.  So we
           can't come up --
                       CHAIRMAN WALLIS:  So that's right, this is
           an example of why you need your RBHT?
                       MR. KELLY:  Exactly.
                       CHAIRMAN WALLIS:  So can we skip to the
           conclusion, do you think?
                       MR. KELLY:  Sure.  And I'll just go ahead
           and skip the convective enhancement.
                       CHAIRMAN WALLIS:  And the rest, we can
           read the summary page.
                       MR. KELLY:  Yes.  The real point here is
           with RBHT we've tried to design the instrumentation to
           give us the information, and Professor Schrock earlier
           talked about the mechanisms.  One of the things to
           look at will be high speed video, and I'm looking
           forward to seeing and looking at high speed video over
           and over again to try to get a better idea of
           physically what's happening.
                       For the convective enhancement by the
           drops, I mentioned earlier there'll be two types of
           tests run.  The steam cooling test, with steady state
           heat transfer forced convection to steam.
                       CHAIRMAN WALLIS:  And you haven't been
           skipping.  I was asking you to go to the end.
                       MR. KELLY:  Okay.  But this is something
           unique about the facility.
                       CHAIRMAN WALLIS:  We can't spend a lot of
           time on all these different items.
                       MR. KELLY:  Right.  And there's the
                       CHAIRMAN WALLIS:  We'd probably need two
                       MR. KELLY:  Okay.  So the code development
           associated with the consolidation effort will be
           completed in the year 2002, probably by the end of
                       The developmental assessment will be
           conducted throughout calendar year 2002.
                       We're going to update the interfacial drag
           and the reflood models; those will appear in the
           consolidated code.  The consolidated code will
           probably be released at the end of 2002.
                       And then long term code development and
           experimental programs will be driven either by code
           deficiencies that arise from the assessment program or
           by user needs for new capabilities.
                       CHAIRMAN WALLIS:  So you're counting on a
           lot of input from this work -- your subcontract?  Do
           we need to have presentations from these people during
           the year so we can see how they're doing?
                       MR. KELLY:  I think that would be a good
                       CHAIRMAN WALLIS:  Should we probably do
           something like that at sometime in the middle of the
                       MR. BOEHNERT:  Sure.
                       MR. KELLY:  I would prefer coming --
                       CHAIRMAN WALLIS:  Again, you don't want to
           us shoot down, let's say, phase separation models just
           before you're putting them in the code?
                       MR. KELLY:  Right.  And Steve -- Steve's
           talks is on the status of these program, but I think
           that's a good idea.
                       CHAIRMAN WALLIS:  There's nothing like
           speaking to the people who are actually doing the
                       MR. KELLY:  Right.  Well, hopefully, we're
           going to be --
                       CHAIRMAN WALLIS:  Maybe at the end of the
           day, but I don't that we'll have any time.  We need to
           think about how the ACRS can be more central to you
                       Although I think when I look at a schedule
           here, I wondered if it wouldn't be better off to --
           well, I guess, Steve, you have two presentations.
                       MR. BAJOREK:  I've got to two of them. 
           The first one --
                       CHAIRMAN WALLIS:  Maybe you should make
           the first one, and then we can have lunch and come
           back for a second one.
                       MR. BAJOREK:  I think that will do well. 
           Well, if you pass out the one handout, what I am going
           to do is I'll just bring out a couple of overheads?
                       MR. BOEHNERT:  This one first, Steve?
                       MR. BAJOREK:  That one first, please.
                       MR. BOEHNERT:  Yes.
                       CHAIRMAN WALLIS:  You're in the last lap
           here, and you've got to make up -- you've got to run
           at double speed.
                       MR. BAJOREK:  I'm ready to go now.  
                       But in the earlier presentations, one of
           the things you may have noticed that Jack noted that,
           in the long run, we're going to be counting on the
           code and more to make regulatory decisions.  The
           accuracy will be much more important to us now then
           they had been in the past, because we're going to be
           relying on TRAC-M, the developers of TRAC-M to come up
           with these decisions as opposed to information that we
           had previously been asking from the vendors. 
                       Joel also in his presentation pointed out
           in the developmental assessment that's going to be
           done over 2002, most of that is being directed at
           completing the consolidation showing that TRAC-M  can
           meet the functional requirements of RELAP, TRAC-B and
           TRAC-P.  The matrix that Joe put up using primarily
           the tests that had been used in the past to try to
           develop the code and assess its performance.  It's not
           necessarily the best set of experiments to use to try
           to determine whether we're doing a good job or what
           we're weak in, or to really characterize the accuracy.
                       So what I'm going to talk about now is
           assessment and quantification of the performance of
           TRAC-M.  But in many ways what this really represents
           in the elements, I think, another five year plan.  The
           consolidation effort is going to go on through most of
           2002.  Through that effort we're not going to be able
           to do the total amount of assessment that we would
           like to have.  So we're looking at work further
           downstream, 2003 and beyond.  What I'd like to try to
           do is layout a better picture of where we think we're
           going to be able to go with TRAC-M, apart from the
           development of the potential model development that
           Joe just talked about.
                       We see three major elements. One, a
           continuing model improvement to get information from
           these test programs, having we things out, they are
           success oriented.  We are assuming that the data that
           we're going to get from the rod bundle heat transfer
           programs are high quality, and likewise for the phase
                       We're talking about those programs that
           are all the things that we're going to be doing to try
           to ensure that we are going to get the right
           information to develop those models.
                       But I think one of the more important
           aspects that we're going to have to address in the
           next one or two years is how do we assess the code
                       We've seen models of the code right now
           that clearly don't perform as we'd like them to.  We
           see TRAC as being "conservative,"  and RELAP being
           nonconservative in the reflood heat transfer.
                       CHAIRMAN WALLIS:  Do you really mean
           uncertainty?  Is that the same thing as accuracy in
           your mind?
                       MR. BAJOREK:  Pretty close, yes.
                       CHAIRMAN WALLIS:  So for the user, the
           user needs to come to us to identify some
           uncertainties in the use of the code, and accuracy may
           be a part of that.
                       MR. BAJOREK:  The way I would break it
           down is we're going to be looking at various processes
           in the code.  We're going to have to assess how
           accurate the code --
                       CHAIRMAN WALLIS:  Well, all codes are
           probably perfect for one point, if you're on the right
                       MR. BAJOREK:  When we get everything in
           there, the issue, of course, is that errors arise. 
           And one of the things I'm going to point out in one of
           the next coming overheads is how we are going to try
           to overcome that.
                       CHAIRMAN WALLIS:  So I say, the second
           bullet is related to the first.  The user uses the
           code and there's some uncertainties associated with
           that.  And that leads to margins and all kinds of
           stuff.  If the uncertainties are reduced, that could
           be model improvement.  For certain applications you
           don't need any model improvement.  But for other
           applications you made a lot of model improvement. 
           It's got to be somehow related to the uncertainties
           which are needed for the purpose of regulation.
                       MR. BAJOREK:  That's why as we go through
           our model development we'll be relying on separate
           effects testing to get this biased uncertainty from
           models.  But an element that we will build in early on
           is how to do those uncertainties propagate a behavior
           when you apply them to a PWR or a BWR.
                       CHAIRMAN WALLIS:  So you're going to have
           some sort of mathematic or analytical framework for
           this?  If you know the uncertainties in this current
           correlation of the model from separate effects tests,
           and then you can predict the uncertainties in the
           integral effects tests and so on?
                       MR. BAJOREK:  Yes.
                       CHAIRMAN WALLIS:  And then you can predict
           the uncertainties associated with some licensing
                       MR. BAJOREK:  Yes.  Many times I've seen
           in the past we've spent an awful lot of time
           developing a model for one process or phenomena only
           to find out that when you arranged it in a PWR
           calculation, it was only effecting your answer by a
           few degrees.  I mean, that kind of tells you that your
           model development effort is being misdirected, where
           as other models --
                       CHAIRMAN WALLIS:  This is risk-informed
           code development.
                       MR. BAJOREK:  Risk-informed without
           development.  But that final piece, seeing how the
           uncertainty needed in the light water reactor
           application is very valuable, because that allows ut
           to redirect our model development. It also allows us
           to refine or define new experiments that we need to
           do.  And that's why what we'd like to try and do with
           the assessment element of this is to start looking at
           light water reactor applications early on, assess the
           uncertainties so that we can account for and correct
           those in the model development efforts.
                       MEMBER SCHROCK:  I don't quite grasp the
           significance of the separate PIRT-based assessment.
                       MR. BAJOREK:  The difference between what
           we are calling a PIRT-based assessment matrix and the
           code consolidation matrix is in the overall scope and
           how the simulations that were performed in the PIRT-
           based give a broader coverage of those processes that
           have been highly ranked in the PIRT.
                       The code consolidation matrix is largely
           historical.  It picks certain FLECHT tests, some which
           are antiquated data, they didn't have the best test
           instrumentation in there by way you could assess some
           of the code models and correlations.  What we would
           like to do is to get away from some of these tests
           that had been used on more of a historical basis,
           broaden that to make use of a broad range of FLECHT
           SEASET, but not rely just on FLECHT SEASET, look at
           the Skewed test, some of the Cosine tests, the
           ACHILLES test and other reflood tests to avoid coming
           up with a code where it may work good for FLECHT
           SEASET, but not do well for other types of experiments
                       MEMBER SCHROCK:  Well, it sounds kind of
           like you have to limit the amount of assessment you
           can do, and so here is a way of choosing more
           important things to perform the assessment on.  But
           that increases the likelihood that there maybe
           something and it's never been understood these things,
           it isn't going to be properly addressed in this new
           code version, and it never will be.
                       MR. BAJOREK:  We'd like to try to expand
           the matrix so it exercises the code over a much
           broader range.  In some ways there's also some economy
           in doing that.
                       A lot of the work in developing these
           input decks for a certain test facility, in some cases
           it takes as much work as it does to set up a PWR or
           BWR deck.  But when you're only going to be running
           one test out of the higher series of tests that can
           run in that matrix, you're losing a lot of information
           that you may gain by increasing the number of tests
           that you look at in that facility.  CCTF or SCTF are
           an example.  The consolidated matrix only looked at,
           I think, one or two tests.  What we're proposing is to
           expand that to look at on the order of 10 or 12 tests
           so you examine how well the code can perform as you
           change things like your boundary conditions, your
           break size, your power distributions both axially and
           laterally within the core.  See how the code uses --
           the sensitivities you can get through the code rather
           than just looking at one point.
                       CHAIRMAN WALLIS:  I would like you to move
           in the direction of risk based assessment.  PIRT is
           just some expert sitting down and saying "Gee, you've
           got to do a better with more than condensation."  I
           mean, there's no measure of better job until you come
           up with things that you're going to use it for.  Use
           it for making regulatory decisions.  
                       So PIRT I never felt was a really good
           measure of goodness of a code, even if it were used
           for that purpose.
                       MR. BAJOREK:  Well, the PIRT's kind of
           done beforehand, and it really only gives you some
           guidance on what --
                       CHAIRMAN WALLIS:  PIRT is a starting
                       MR. BAJOREK:  Right.
                       CHAIRMAN WALLIS:  But it doesn't give you
           a measure of success.  And I think you really need to
           think more about what is the proper measure of success
           for a code.
                       MR. BAJOREK:  Let me jump ahead for that
                       MS. UHLE:  Can I answer Professor
           Schrock's question?  
                       MEMBER SCHROCK:  I think he said it okay. 
           That really results in more assessment than less.  I
           have a feeling that it is maybe limiting the amount of
                       MS. UHLE:  I think it's just focusing on
           where we're going to start first and then getting
           gradually to the lower things.
                       MEMBER SCHROCK:  Yes.
                       MR. BAJOREK:  Paul, if you pass out that
           other set --
                       MR. BOEHNERT:  This one?
                       MR. BAJOREK:  Yes, that one.  This is the
           proposed assessment matrix that will be used following
           the code consolidated assessment matrix.  If it came
           out well in this, we would continue to do tests
           looking at tube barometers, types of tests where you
           know you can do a hand calculation to come up with the
           answer that maybe the code has to deal with to perform
           those tasks before it could go on to the others.  This
           is a way of checking to make sure your latest code
           change goes through appropriately.  But the difference
           between the consolidated matrix and what we would be
           doing in what I'm calling this first development
           assessment matrix, we would greatly expand what we are
           looking at in the FLECHT SEASET facility so that we
           could look at how the code performs for a forced
           reflood, when we change the reflood rate --
                       CHAIRMAN WALLIS:  What's your measure of
           performance? In your two-phase pressure drop here
           you've got to do some comparisons.  How do you know
           when it's good enough?  Maybe a factor of 2 or 10 is
           good enough two-phase pressure drop.  How do you know?
                       MR. BAJOREK:  Part of that comes from what
           we get out of ranging the bias and uncertainties at
           the light water -- in the light water reactor.  So
           coming up and let me go -- I'll jump to this, and let
           me show you --
                       CHAIRMAN WALLIS:  You really have to do
           the CSAU thing and look at how does it effect things
           that matter, like peak clad temperature or something. 
           Then say, have we got a good enough code.  Don't you
           have to go to the things you're trying to predict for
           regulatory purposes and the sensitivity of those are
           the things that you look for.
                       MS. UHLE:  That comes out of the fact that
           these models will probably be ranked --
                       CHAIRMAN WALLIS:  But the PIRT doesn't do
           any of that.
                       MS. UHLE:  Well, sure it does.  It tells
           you what experts are thinking of.
                       CHAIRMAN WALLIS:  It doesn't tell you
           what's good enough.
                       MS. UHLE:  It does in a sense that --
                       CHAIRMAN WALLIS:  What an expert's
           thinking is really often self-serving.  They say I'm
           an expert on flow regimes so you need to do more work
           on flow regimes.
                       MS. UHLE:  And then in our first
           experiments we focus on those models that people point
           out as most important. 
                       MR. BAJOREK:  We look at the reflood heat
           transfer to determine how well it behaves, and we have
           looked at some of the reflood tests and we would see
           how those uncertainties behave in the full scale.
                       Now, if we continue to see very large
           uncertainties, that's an indication that we need to go
           back --
                       CHAIRMAN WALLIS:  If it effects the
           regulatory decision.
                       MS. UHLE:  Right.
                       CHAIRMAN WALLIS:  Yes.
                       MR. BAJOREK:  So if we range the reflood
           heat transfer over its broad range of uncertainty
           based on how we see it in separate effects, but it
           doesn't make any effect anymore on the peak cladding
           temperature, that says we should look more at things
           like bypass or condensation.  I don't think we're at
           the point where we can rule any of those out.
                       MEMBER KRESS:  Rather than look for what
           range it's asking as measured as how good is good
           enough, I think your aim ought to be being able to
           capture the uncertainties.  And then if you can
           capture then, you can say how good your prediction is
           with respect to any of the reactions and then your
           decision process could factor in those uncertainties
           on whether or not it's good enough.  So again an
           application --
                       MR. BAJOREK:  Once can capture them how
           well the code's performing based on the separate
           effects then we can see how it behaves.
                       MEMBER KRESS:  So how is the code going to
           be able to kick out for you the uncertainties.
                       MR. BAJOREK:  If we don't get to that step
           and we see a large change or no change in the light
           water reactor, you don't know whether it's because the
           code is doing input or not or whether it's exhibiting
           the right sensitivities.
                       MS. UHLE:  Another thing, too, focusing on
           the separate effects test is the fact that if you just
           focus on the integral effects test you're not sure if
           the answer isn't changing because of compensating
           errors.  And that's what the separate effects tests
           really highlights.
                       MR. LAUBEN:  No, the point is that there
           is nothing like the regular development of --
                       CHAIRMAN WALLIS:  No, I'm saying that I
           think the PIRT is based on experts, the wrong experts.
                       MR. LAUBEN:  Right.
                       CHAIRMAN WALLIS:  They're not your
           customers.  They're just the people who are looking
           for work.  They're the wrong group.
                       MS. UHLE:  Any PIRT contributors here? 
           All right. So any PIRT you were involved in we'll
           throw out.
                       MR. LAUBEN:  But if you were to go through
           the process we talked about today, you'd start out
           with some kind of PIRT and during the process you'd
           focus in on, at the highest level, like you were
           saying the ability to predict a regulatory effect on
           the peak cladding temperature, and all of the top
           level things.  The PIRT may change.  The PIRT may
           start out as something, and what is critical changes
           throughout your whole process.
                       MR. BAJOREK:  And it does.  I mean, if you
           look at the PIRTs that are designed for conventional
           PWR, versus AP600 or AP1000; there are small but
           perceptible changes in all those, and what's important
           in one transient versus the next --
                       Our problem is making sure that the code
           can deal with those things which people have deemed to
           be very important and then can also deal with those
           things which are deltas between plants that have been
           looked at in the past.
                       Now, I think part of the problem in this
           assessment, I think has just been pointed out, is a
           lot of folks have focused on solely the peak cladding
           temperature as being your sole measure of a code
           performance.  And what I did is I grabbed a couple
           rolls of technical papers and, actually, I took one
           out of CSAU NUREG for example, how does your code
           behave.  And the common way of doing it is looking at
           the peak cladding temperature from the scout point. 
           A plot, if you were, where you predict the PCT as
           higher than the measured, you deem that it's being
           conservative and say that your code's conservative
           forgetting the fact that there may be other things
           going on in these experiments, CCTF and SCTF in steam
           binding and the steam generators that may be
           contributing to the performance of your core heat
                       Another way would be taking these tests,
           mix them in with separate effects tests, which is done
           over on this figure on the left hand side, and use
           that to get a gauge of your code performance, or in
           this case as this had been designed to, is well let's
           just get a delta PCT and you would simply put that on
           as an adder towards some calculation that you would do
           for, in this case, the PWR.
                       I think the perception now, and correctly
           so, is that approach is incorrect because it doesn't
           deal with compensating errors. It doesn't deal with
           new ranges and conditions and tells you nothing about
           whether you're getting things like super heat, drop
           break-up correct, all of the intricacies of reflood
           heat transfer that go into calculating that peak
           cladding temperature.
                       Now, we intend to expand the test matrix
           that we're going to for the separate effects tests,
           but at the same time which when you get away from this
           type of a measure of the code performance.  This is an
           example of typical practice, and the one I just showed
           you -- I've got my greater than and equals sign in the
           wrong direction here.  The one where I just pointed
           out is to take a look at solely the peak cladding
           temperature, it says your coding is conservative if 
           your predicted is greater than the measured.
                       Now another way, and Joe alluded to it in
           his presentation, is to look at the one model in
           reflood that's perceived as having the greatest
           effect.  Okay.  This has been done by taking a look at
           the dispersed flow film boiling heat transfer
           coefficient; defining a bias and an uncertainty.  And
           in this particular application then the uncertainty in
           that particular model was used to range at full scale
           in order to get delta PCTs in the full scale case. 
           PWR in this case.
                       We're going to take advantage of more
           detailed test data like we're getting out of the rod
           bundle heat transfer program and information that we
           can glean from other test programs to increase the
           total number of peak performance parameters before we
           can claim success in any one of the models, and I'm
           going to reflood as an example.
                       Our approach now is we can use multiple
           parameters is to try to characterize specific models
           within the package and the package in total. Okay.  We
           will not rely on simply peak cladding temperature as
           the sole performance indicator.  For reflood heat
           transfer the type of things that we would get out of
           the assessment after we have done the simulations and
           comparison to data, the FLECHT SEASET, that larger
           number of tests; the FLECHT Skewed, the FLECHT
           ACHILLES, the other ones that I have listed on there,
           is to look at break things up into heat transfer
           regimes.  Look at those periods where the test and the
           code were predicting steam cooling heat transfer, and
           use this as a performance measure by defining a bias
           and uncertainty essentially to characterize how well
           the code is characterizing and calculating in a single
           phase performance.  We would still do the dispersal of
           film boiler heat transfer coefficient as we've done in
           the lab, in case you're not aware of.
                       Joe noted that near the quench front,
           okay, we also have some very important precursory
           cooling.  And we want to know whether the bias and
           uncertainty in the models that we develop and put into
           the TRAC-M are reasonable compared to the experimental
           data that we get out of the rod bundle and we can also
           get out of some of the other tests.  And this is one
           case where we might want to jump very quickly to take
           this biased uncertainty and use those or study those
           in a light water reactor application and give us an
           indication should we be looking more closely at
           inverted annular flow, okay?  Or, should we continue
           to focus on steam cooling dispersed flow film boiling
           which has been more typical of the past.
                       The answer to that in those simulations 
           would be whether we're seeing very large uncertainties
           in the light water reactor application, very large
           delta PCTs.  That would be an indication that the bias
           and uncertainty that you are imposing on the code by
           a model selection and model development would be
           unacceptable.  It might mean another experimental
           program or it could at least mean you would have to go
           back, sharpen our pencils and come up with a better
           model and do some additional assessment.
                       MEMBER KRESS:  Is the plan incorporating
           these biases of uncertainties into the code itself and
           combining in some way with the Monte Carlo, for
                       MR. BAJOREK:  In the long run, yes.  Right
           now we don't have any plans to put in into the input
           structure in the TRAC-M the way of incorporating these
           biases or uncertainties easily.
                       MEMBER KRESS:  It seems to me like that
           should be your eventual goal?
                       MR. BAJOREK:  I think if we start to see
           it -- we did want to have some kind of input or some
           way within the code structure that we could range
           these things easily without depending on either the
           developer or the user to actually go into the code and
           hard wire the changes, which is the way I've seen this
           thing done in the past.
                       MS. UHLE:  A good thing about the
           modernization, too is the architecture.  The physical
           models are isolated from any of the -- associated with
           the alphanumerics.  And so the correlation in a
           specific sub routine is either divided or multiplied
           by that value, and have that propagate through the
                       MR. BAJOREK:  It has also quite helped us
           to get away from relying on that group of experts that
           helped develop PIRT.  Because once we try to develop
           a larger range of performance perimeters, and have
           really to range those in the light water applications,
           now we can go back and say ah-ha, this should have
           been on your PIRT and this was missed or hopefully you
           guys did a job.
                       MEMBER KRESS:  I worry about arranging
           them individually one at a time.  That's why I
           mentioned in Monte Carlo, you can get away from that.
                       MR. BAJOREK:  The way we had done that at
           Westinghouse was to look at things one at a time and
           then develop a response service methodology to try to
           incorporate how combinations of things can change. 
           That also was driven by a couple of different things.
                       One, it was always nice to go to the user
           and say "This is what you're going to do because this
           is what was approved," very clear cut.
                       Another approach, and I think that has
           been used more in Europe and we are going to be
           looking at that in the long run, is I think is a GRS
           sampling approach or refer to it as a German sampling
           approach.  I thought that was Oktoberfest.
                       But what this does is it looks at a broad
           range of uncertainties and simultaneously picks and
           ranges multiple perimeters, and puts that in your
           simulation, samples that distribution many times that
           gives you an uncertainty in your peak cladding
           temperature, your equivalent clad reaction and also a
           confidence interval.  If you don't like that
           confidence interval, do it more times.
                       Now, the nice thing is that it seems as we
           spend more time in these meetings computers continue
           to get faster.  And what would seem, you know,
           absolutely insane ten years ago, making a hundred PWR
           or BWR calculation, is now something that can be done
           in a reasonable amount of time.  So that type of
           approach now I think is something that can and should
           be looked at in the long run.
                       But anyway, we're going to break up, for
           example, reflood into multiple performance perimeters, 
           in some we are going to look at specific model and
           processes.  I wanted to add a couple on here to try to
           address the hydraulics, although it doesn't
           individually get at flow regime transition or
           interfacial drag, but carry over fractions.  Rather
           than just taking a look at mass affluent and what the
           code is predicting, it applies an uncertainty for as
           many of these tests that you can so we can determine
           if the code is doing a good job or not in calculating
           things like entrainment drop size.
                       Level swell, or another way I would say it
           interfacial drag below the quench front.  And see for
           a given amount of mass has the quench front propagated
           too high into the bundle.  
                       And in those characterized individual
           models or call them packages, we can use things like
           quench time, clad temp and steam temperatures, these
           are in the program that was developed at Penn State
           called ACAP that essentially goes through and takes a
           look at a predicted trace versus a measured trace and
           gives you statistics on how well that curve
           corresponds to one another.
                       I'd like to think it a little bit more as
           the integral of this curve behaving much like the
           integral of the other curve.  This, again, starts to
           get closer towards the peak cladding temperatures
           you're looking at things that's an aggregate, but we
           think by defining several key performance perimeters
           and making our holy grail the idea that we're going to
           get all of these simultaneously in some reasonable
           bias and uncertainty where reasonable at this point
           still is yet to be defined, because when we go through
           the first cuts and range those in PWRs and BWRs,
           that's going to start to tell us what is reasonable,
           whether we're looking at hundreds of degree change in
           clad temperature or a few degrees.
                       Most of this work will not begin until
           late 2002 with the release of the Rev 0.0 version. 
           2002 is going to be primarily those tests that are
           being used in the consolidated assessment.   What I
           wanted to note on here is what we would be doing is
           expanding the database both in the total number of
           tests that would be looked at in an individual
           facility and in the total number of facilities that
           would be factored into the assessment.
                       Some of these tests will be done in 2002
           once we get close enough with the Rev 0 version,
           because one of our first applications is going to be
           the AP1000 large break LOCA.  So we not only have the
           work at performance for reflood heat transfer, but
           also things like bypass, we're going to be very
           interested in the performance of the code for how well
           it does for direct vessel injection.  So we would be
           look at tests like UPTF 6 and 21 phase D to get the
           direct vessel injection, and also one of the CCTF
           tests that also gets --
                       CHAIRMAN WALLIS:  All right.  Can you
           finish by 12:30?
                       MR. BAJOREK:  Yes.
                       Integral tests also captured in the
           assessment matrix would expand the number, the total
           number of facilities.  What we would be looking for
           there is, does the code give us the type of
           sensitivities that were observed in these various
           tests.  What would we do if we would look at, for
           example, SCTF and the difference between flat radial
           shape and the very peak radial shape, in the sense
           that we are able to get that same type of a variation
           in TRAC-M.  We wouldn't get that if we just looked at
           one test.  
                       And you can see some of the other
           sensitivities we would hope to get out of the integral
           effects tests.
                       The eventual goal then is defining the
           uncertainty for a large number of models, develop the
           capability of range and base and assessing their
           importance in the full scale plants, peak cladding
           temperature and their effect on normal clad reaction. 
           As we start to see plants being operated, they're now
           staying at higher temperatures for longer periods of
           time.  Our concern from a risk based regulation is
           that maybe peak declading temperatures is what we're
           going to have to look at in the future, so we're going
           to have to start looking at clad ductility and clad
           reaction rate in a lot more detail than it had been in
           the past.
                       As we mentioned, if we start seeing large
           uncertainties in the light water reactors, that's an
           indication that we either have to look at test data
           closer or we have to go back to develop better models
           for the process we're interested in.
                       We see this as being one of our major
           activities over the next 3, 4 or 5 years.
                       And by way of summary, we're going to
           expand the consolidated test matrix to look at a
           larger number of conditions, a larger number of test
           facilities.  We're going to use this quantified code
           to model accurately and engage what goes on in the
           other plants.
                       CHAIRMAN WALLIS:  You have a lot on your
                       MR. BAJOREK:  There's a lot there, yes.
                       One of the things we are going to try to
           do in 2002 is automate the process.  It's a lot of
           work and there's a lot of comparisons to data.  If we
           do a good job on the first few tests, capturing the
           scripts to do the comparisons, setting up the methods
           to run these things in mass and do comparisons to
           mass, we may save -- we'll definitely save ourselves
           a lot of grief and agony further downstream.
                       MEMBER FORD:  You've got the data
           scattered around the one to one correlation like that
           what is your matrix of success?
                       MR. BAJOREK:  It's going to be in the
           several parameters that were defined for reflood
           rather than PCT. The matrix would be to have all those
           at a reasonably small bias and uncertainty.  Now,
           reasonable, I think in the past people have basically
           looked at 5 or 10 percent in bias and uncertainly on
           the order of 30 to 50 percent.  A lot of that just has
           to do with the scatter of the experimental data.
                       MEMBER FORD:  I was about to say that
           surely that the scatter is obvious in the experimental
                       MR. BAJOREK:  Right.
                       MEMBER FORD:  But your model should be
           able to predict that step.
                       MR. BAJOREK:  For the different condition,
                       MEMBER FORD:  Well, for the -- that
           scatter is presumably due to uncontrolled experiments,
           but you can quantify that, the degree of lack of
           controls.  So can you not -- would you not -- your
           matrix of success be that you can bound your observed
           scatter?  Not only in the experiments, but also in the
           reactor?  I mean that's the uncertainty --
                       MR. BAJOREK:  You would hope that if you
           define, let's say, bias and uncertainty in a model,
           when you apply that in the separate effects
           simulation, you also can show that you've bound or you
           -- excuse me.  You bound it in the separate effects
           tests and you are confident finding delta C in the
           whole scheme.
                       MEMBER FORD:  The wider reasoning behind
           my question is that asking for the matrix of success
           if a licensee comes in with their own code, do you use
           your code?  I mean, I know why you're touting your
           code, to be an informed reviewer, but at what point do
           you say this model is no good based on a matrix like
           that in comparison to the observational query.  Does
           yours do better than he or --
                       MR. BAJOREK:  That's what we're hoping.
                       MEMBER FORD:  And if that happens, then do
           you say he can't use his code?
                       MR. BAJOREK:  No, because I think what
           happens is if you do a good job on your code, you
           should have a relatively small uncertainty when it's
           propagated.  If you did a poor job on the code, that
           should grow. 
                       So, if you come in with a code that does
           not perform well against separate integral effects
           tests, the price you pay is a larger uncertainty of
           the whole scale application.  My twist on that is if
           your code doesn't have the right sensitivity, I guess
           that's a question we have to look into.
                       CHAIRMAN WALLIS:  Steve, we're going to
           see you after lunch?
                       MR. BAJOREK:  Yes.
                       CHAIRMAN WALLIS:  What I propose is that
           we break for lunch and we get back here by 1:00?  Can
           you do that, have a quick lunch.
                       MR. BAJOREK:  How much time do we have
           after lunch?
                       CHAIRMAN WALLIS:  2:30.  We'll be back
           here at 1:00.
                       (Whereupon, at 12:33 p.m. the meeting was
           adjourned, to reconvene this afternoon.)
                                A-F-T-E-R-N-O-O-N  S-E-S-S-I-O-N
                                                    (1:08 p.m.)
                       MR. BAJOREK:  This afternoon what we'd
           like to start doing then is looking at and reviewing
           some of the work that has been done over the past year
           on the experimental programs that we're relying on
           right now to solve some of the major thermal-hydraulic
           issues, and also to give us some additional data for
           the code development.
                       The ones that we're going to talk about,
           a couple of these we may move quickly because we've
           talked about these back in July, are:  
                       APEX, work that has been going on there to
           address the pressurized thermal shock; work that has
           been going on at the PUMA facility, Purdue University.
                       The work that has been going on to take a
           look at critical flow, and we anticipate using the
           facility to take a look at the BWR boiling
           instability, the flow instability.   
                       The rod bundle heat transfer program at
           Penn State.
                       ATLATS or the phase separation work that's
           being done also at Oregon State University.  
                       I'm going to present some work that has
           been recently given to us by Vijay Dhir at UCLA
           looking at subcooled boiling.
                       And finally, we'll wrap up taking a look
           at the interfacial transport project that's being done
           at Purdue by Dr. Ishii, also Kajasoy at the University
           of Wisconsin, Madison.
                       But for the work that's been done in 2001
           in APEX, APEX in late 2000, maybe a little bit
           earlier, had been modified to look much like a
           combustion engineering unit.  It took advantage of the
           fact that the APEX facility in its original format for
           the AP600 had a 2 x 4 loop, the pumps were replaced. 
           Excuse me.  The can pumps were replaced in the APEX
           facility with loop seals and pumps so that it would
           look much like Palisades and Calvert Cliffs.
                       Most of the experimental work that has
           been going on in APEX over 2001 has been designed to
           take a look at PTS issues.  
                       Now, we presented a lot of this
           information in July of this year when we also got to
           see a test at APEX.  And I've got a couple of
           overheads to summarize the PTS work.
                       Most of the work that is going to be
           planned at APEX for 2002 is going to be directed
           towards the AP1000.  Dr. Rais was recipient of a DOE
           MURE grant earlier this year.  This gives him funding
           now to modify the APEX facility to replace the heater
           core, enlarge the pressurizer, change the core makeup
           tanks, add some additional instrumentation so that it
           looks much more like the AP1000.  And that's the work
           that will be going on later in 2002.
                       Now the PTS work that was being done at
           Oregon State was the central part of three overall
           components to take a look at PTS.  OSU, the APEX
           facilities, was used to develop the experimental
           database, look at downcomer mixing effects.  This was
           accompanied with RELAP and REMIX calculations to try
           to gauge how quickly these plumes would dissipate in
           the downcomer.  This was accompanied by a thermal-
           hydraulic uncertainty evaluation that was done at the
           University of Maryland.
                       CHAIRMAN WALLIS:  Is that still being
                       MR. BAJOREK:  It's finishing up right now.
                       Following the meeting in July/August time
           frame, Dave Bissette decided that they needed some
           additional tests to add to the ones that had been
           previously done.  They started doing those in
           September/October time frame.  As of October they were
           almost done.  I think they still had a couple more to
                       CHAIRMAN WALLIS:  Final report is in
                       MR. BAJOREK:  December. Yes, the end of
           this year.
                       The work in the facility as it is right
           now, scaled as I mentioned to the CE plants, the work
           that had been done --
                       CHAIRMAN WALLIS:  The question is whether
           or not this has been adequate to resolve the PTS --
           they've done something to my mike?  They took it away. 
           Someone took it away.  Oh.  Yes.
                       MR. BAJOREK:  I believe it is.  Is Dave
           Bissette here?  I think he's left.  But --
                       CHAIRMAN WALLIS:  There's a mike here.
                       MR. BOEHNERT:  No, it's the table mike.
                       CHAIRMAN WALLIS:  There's a mike here.  So
           we're okay?
                       MR. BOEHNERT:  Yes.
                       MR. BAJOREK:  From my understanding,
           they're going to be able to wrap up the tests this
           year, issue the final report and I believe that is
           going to resolve the PTS issue, which leaves us for
           upcoming events.
                       The early part of the year will be
           occupied primarily with finishing the testing, writing
           the final report.  Excuse me.  Not the end of this
           year, that's going to be due the end of January.  But
           starting the end of this year and into most of 2002
           leading towards the end of the summer, the facility is
           going to be modified.  The larger-diameter heater rods
           in the core are going to be replaced with smaller-
           diameter rods.  They're going to put in a new data
           acquisition system.
                       The pressurizer in the AP1000 is
           substantially larger than it is in the AP600.  That's
           being replaced.  Likewise, the CMTs.  CMTs are larger
           in the AP1000, they also have a different type of
           orifice to reduce the form loss from the CMT into the
           DVI line.
                       CHAIRMAN WALLIS:  Do you know what the
           licensing schedule is likely to be for 1000?
                       MR. BAJOREK:  Right now we're scheduled to
           issue an SER early next year.  I'm not sure exactly --
                       CHAIRMAN WALLIS:  So these tests will come
           after the SER has been issued?
                       MR. BAJOREK:  I'm sorry.  SER for phase 2
           of the review.  Phase 2 of the review is taking a look
           at the codes, for their adequacy, taking a look at the
           test and the analysis program.  And we're going to be
           issuing our opinion on those, probably March or so of
                       Phase 3, Westinghouse decides to go ahead,
           they would be issuing their analysis, the finalized
           design and then going through the rest of the review. 
           I think the SER for that would have to be sometime
           late in 2003/2004.
                       CHAIRMAN WALLIS:  So your results will be
           timely enough input?
                       MR. BAJOREK:  Yes. Yes. It seems very
           aggressive and ambitious, but they're hoping to do all
           of this modification to the facility and be able to
           begin hot down testing the end of next August. If that
           were the case, testing would begin later in 2002 and
           probably continue well on into 2003.
                       CHAIRMAN WALLIS:  Now is the government
           doing some analytical work to figure out what key
           tests need to be run?
                       MR. BAJOREK:  DOE asked us several months
           ago to comment on the text matrix.  They made it clear
           it is their test.  We gave them some recommendations
           based on previous tests that have been run in the
           AP600.  The ones there that had been the most
           interesting from a licensing standpoint were the DVI
           line breaks, cold leg breaks, okay, where you had
           multiple failures and failures of the ADS-4 system. 
           Those are the ones that gave the minimum inventory in
           those tests.  And we would presume that those tests
           would also generate the minimum inventory in the
                       At the top of the list is the DVI line
           break.  That one, by far and away, seemed to be
           generate the minimum inventory.
                       One of the things that I've been involved
           with over the summer and the last couple of months has
           been in a scaling analysis for the AP1000 in the test
           program.  Part of our concerns stemmed with what will
           go on in the facility -- or more, the full scale plant
           during this ADS-4 period.
                       The DVI line break is clearly going to
           make entrainment in the upper plenum pool, entrainment
           in the hot leg, into the branch line much more severe
           than it was in the AP600.  Going from AP600 to AP1000,
           that's a 73 percent increase in the core thermal
                       The vessel is the same diameter.  The hot
           leg is the same diameter.  So having this additional
           core power is going to greatly increase the
           superficial velocities during the ADS-4 period and
           also during the long-term cooling period.  So we're
           looking at that.
                       We did make a recommendation that they add
           instrumentation to try to get the branch line quality-
                       CHAIRMAN WALLIS:  That's the sort of thing
           I had in mind.  If you'd thought about what are going
           to be the big differences that we need to worry about,
           therefore design the experiment so they focus on the
           right thing?
                       MR. BAJOREK:  Yes.  But those tests will
           start later in the year and I look forward to seeing
           some of those results.
                       PUMA is the integral test facility that
           represents the SBWR. It's located at Purdue
           University. It's an integral test facility that has a
           reactor pressure vessel, internal components to
           represent the core, downcomer, chimney and separator.
                       Most of what has been done over 2001 has
           been used using the the facility as a separate effects
           test.  Now, this also stems from work that was noted
           in AP600, again during this ADS-4 blowdown period. 
           Rather than critical flow at higher pressures being
           the most important break flow phenomena or range of
           conditions, during the ADS-4 we have critical flow at
           a relatively low pressure.
                       During the AP600 analysis using RELAP it
           was noted that one of the deficiencies in the code was
           the performance of its critical flow model during this
           lower pressure period.  They've been gaining some
           additional information in the facility corresponding
           to these lower pressures, making use of some advanced
                       The long range intended use in 2002 is to
           start to look at the BWR flow instability problem.
                       CHAIRMAN WALLIS:  You're saying that PUMA
           is going to be used to look at critical flow at low
                       MR. BAJOREK:  It has been.  It has been.
                       CHAIRMAN WALLIS:  It has been?
                       MR. BAJOREK:  And what I'd like to do now
           is Weidong Wang has a few overheads to describe that
                       MR. BOEHNERT: What's the issue with flow
           instability?  Has it been looked at or -- are you
           going to talk about that?
                       MR. WANG:  Yes.
                       CHAIRMAN WALLIS:  I suppose that these
           valves are going to be tested anyway for ADS-4?
                       MR. BAJOREK:  Not the ADS-4.  They've
           tested the ADS 1 through 3.  
                       CHAIRMAN WALLIS:  Oh, it's too big to
                       MR. BAJOREK:  Right.
                       CHAIRMAN WALLIS:  Blowdown from a valve
           isn't something you predicted, right?
                       MR. BAJOREK:  Yes.  The AP1000 you get a
           preset line size --
                       CHAIRMAN WALLIS:  And it's like a straight
                       MR. BAJOREK:  Yes.
                       MR. WANG:  My name is Weidong Wong.  I'd
           just like to give you a little overview about PUMA
                       I will basically deliver an overview of a
           PUMA project and also talk about critical flow and why
           we do that, and also inflow instability and the status
           for the plant for the coming year.
                       This PUMA facility is the only operational
           facility for the next generation SBWR in the United
           States.  And the facility is a scientifically scaled
           from SBWR and it has extensive instrumentations, over
           500, for flow void fraction.  And Steve just went over
           all this.  And I just give you a few pictures,
           cartoons that let you have a better idea about what it
           looks like.
                       This is a schematic of what this PUMA
           facility.  And they have a reactor vessel just very
           tall like a pen here, a pen.  And this is containment,
           and it's a compression pool, basically it's a separate
           component and connected by pipes.
                       Just give you a few pictures so that you
           know what we are talking about.
                       And this is the size of the dry well
           containment.  You do not have these pictures because
           I have difficulties because it's white -- black and
           white.  And it's not real clear.  And here inside is
           the vessel and the people are working here.
                       So you will see it's a pretty large
                       And this is a control room, and there are
           people working there.  And they have extensive
           instrumentations and they're all monitored by these
           computers or televisions, because we can see the
           bundle and the boiler fraction goes through core
           vessel or in the compression pool.
                       And Y which is for the critical flow, as
           Steve just mentioned about, actually we know critical
           flow from the light water reactor is important under
           low pressure, because either that they are all AP600,
           they have automatic deprivation systems. 
                       And at a low pressure, basically
           mechanical non-equilibrium for the liquid phase and
           the vapor phase, so the last thing is that can be
           large due to density ratio.  And also thermal non-
           equilibrium can be large.
                       And for our code TRAC-M and RELAP5 we note
           basically it's assessed for the pressure above 500
                       And the shortcomings for the previous
           tests, first of all, we know it's not -- they do not
           have a detailed in-line measurement for the critical
           flow and also no systematic experiment to address the
           mechanical non-equilibrium and thermal non-equilibrium
           and the pressure effects.
                       And I tried to quickly go over some
           examples results and then give you the conclusion,
           because of time.
                       This is one of the example results. 
           Pressure effect for the slip ratio.  You will see from
           here the quality -- okay, this here different
           pressures.  With the low pressure like for 30 psi with
           the experiment we have to go either from 30 psi to 150
           psi. And you'll see this slip ratio can be very
           significant here.
                       CHAIRMAN WALLIS:  This is for what?  Flow
           through a nozzle or something?
                       MR. WANG:  I have two plugs, actually.  We
           plug both for nozzle and for the orifice.  For this
           particular one, it is for the nozzle. And basically
           for the nozzle and for the orifice we saw the same
                       And this can tell us, you know, for the
           the AP600 application -- first, we had difficulties
           with original critical flow model. Then later we
           developed some temporary or interim critical flow
           model.  Use Henry Fausky, which is a homogenous type
           of flow model.  And then here you will see, at a very
           low pressure, the slip ratio can be high.
                       MEMBER SCHROCK:  Of course, your earlier
           experiment wouldn't be very good for flashing critical
           flow, would it?
                       MR. WANG:  We have went through --
           basically we tried to study this mechanical non-
           equilibrium, thermal non-equilibrium, and for chemical
           non-equilibrium we used air and water.  And for the
           thermal non-equilibrium we used super-cooled water and
           the flow between we basically used saturated water and
           steam to make this experiment.
                       MEMBER SCHROCK:  You misunderstand the
           intent of my question.  As liquid is vaporizing it's
           adding more momentum mass to the vapor phase.  That
           phenomenon doesn't occur to your water experiments. 
           So the question, is the adequacy of information from
           air-water experiments in flashing steam flow
                       MR. WANG:  Well, certainly, I'm not sure
           for the answer, but I think that we have a
           parametrical study basically for this -- our objective
           to get mechanical non-equilibrium and here, if we have
           a pressure, it's high enough.
                       CHAIRMAN WALLIS:  Well, this slip ratio is
           very dependent on the flow regime.  If you have
           flashing mixture which is breaking up into droplets
           because of flashing, it's very different from
           something like an annular.  So you have to be pretty
           careful about duplication.
                       MR. WANG:  This slip ratio actually is
           measured above the break point.  It's not really at
           the choking plane And basically we've --
                       MEMBER SCHROCK:  Measured where?
                       MR. WANG:  Above the break point.  This
           measured in -- we measured the void fraction and then
           we measured the quality.  And these void fraction, we
           measured it by impedance meter, and this quality is
           computed by the inlet of this critical flow.  And from
           this correlation we calculate -- from this equation we
           calculated the separation and tried to see under this
           low pressure condition this slip ratio of water
           relation or with slip ratio with this -- with
           pressure.  And certainly this one can not really
           represented as the choking plane but it can tell you
           something about the slip ratio.  It's important at
           this choking plane.
                       I'll give you another example for the test
           results.  Subcooled water.  And from here I have
           showed 150 psi for the orifice and a nozzle. And
           therefore we focus on one of this same pressure and we
           noticed that for the nozzle have a higher critical
           flow mass rate.  And for the orifice -- for the
           orifice it is smaller.
                       CHAIRMAN WALLIS:  What area is this based
           on?  This is based on the total area of the orifice
                       MR. WANG:  Yes.
                       CHAIRMAN WALLIS:  No vena contracta or
                       MR. WANG:  Right, for the orifice, right.
                       CHAIRMAN WALLIS:  You expect something
           like this from the contraction.
                       MR. WANG:  Right.  And here, we tried to
           -- basically tried to see what is important factors
           for this thermal or mechanical non-equilibrium and we
           concluded basically -- I say we, this project is done
           at Purdue University -- and we have concluded because
           say if you only have this orifice and the orifice,
           since it's short, and it doesn't have much time for
           the liquid to evaporate. And we expect some kind of
           higher critical mass flow rate, but we see here it's
           smaller.  And we conclude that basically it's a
           mechanical non-equilibrium is more important than
           thermal non-equilibrium.  This is all that we wanted
           to say here.
                       CHAIRMAN WALLIS:  When you compare a
           nozzle with an orifice, how do you decide what's the
           effective flow area for the --
                       MR. WANG:  We use the same flow area.
                       CHAIRMAN WALLIS:  You don't have a
           contraction coefficient?
                       MR. WANG:  Yes, we do not.  We'll use
           that, but we expect, of course, for this orifice you
           have a higher loss, but here we focused on the
           orifice, first for the geometry basically for the --
           for the nozzle, the lighter liquid -- lighter vapor
           have a high acceleration.  This is also is not a
           explanation.  But we really try to here to see what
           the effect of the thermal or mechanical non-
                       MEMBER SCHROCK:  I don't think you've got
           it right.  Critical flow rate is going to depend so
           strongly on where the flashing begins.  The orifice is
           not going to behave like a nozzle.  I think you're
           seeking an answer to a question which is -- may be a
           reasonable question, but I don't think your approach
           is going to get you there.
                       MR. WANG:  Okay.  We'll feed it back this
           to Professor Ishii and we'll have more discussion and
           try to get back to you.
                       And these tests show you the examples
           related to this, because the code cannot really
           predict the data well.  This is the RELAP5 prediction
           for this critical flood, 30 psi for the orifice case. 
           And also we should check on here there's some bigger
                       Just gave a summary of this program.
                       And for the critical flow we have
           basically 15 to 25 percent higher flow rate for the
           nozzle than orifice.  And we notice a larger slip
           ratio with the lower upper-stream pressures.
                       MEMBER SCHROCK:  In the Purdue work is
           their critical flow measurement using water?
                       MR. WANG:  Basically we have -- the upper
           stream is controlled and we use a steady state.
                       MEMBER SCHROCK:  Well, you've shown us
           data for air water systems.  And I would argue, just
           in general, one should not expect to get critical flow
           phenomena where splashing water is based on air/water
           measurement.  They're quite different systems.
                       CHAIRMAN WALLIS:  Well, I think that the
           subcooled water test must be for water alone.
                       MR. WANG:  Subcooled water, yes it's for
           water alone.
                       MEMBER SCHROCK:  Water alone?
                       CHAIRMAN WALLIS:  So what you're telling
           us is that the code's probably not going to give a
           good prediction for this ADS-4?
                       MR. WANG:  Right.  And we tried to get
           some data and see, in the future model development, we
           use this data to develop some better model or at least
           we have some data here and maybe for the critical flow
           models there's some adjustment we can use to improve
           the prediction.
                       CHAIRMAN WALLIS:  Presumably, AP600 was
           licensed on the basis that the critical flow
           predictions were okay.
                       MR. WANG:  We do have done some work to
           predict this -- improve the AP600 and --
                       CHAIRMAN WALLIS:  After they built it,
           then they have to open ADS-4 on a running reactor?
                       MR. STAUDENMEIER: Yes.
                       CHAIRMAN WALLIS:  I thought they were
           going to be full scale tests.
                       MR. STAUDENMEIER:  For the valve
                       CHAIRMAN WALLIS:  That's going to be the
           proof of the pudding.
                       MR. WANG:  Thank you, Joe.  And also
           actually, maybe the flow regime use is --
                       CHAIRMAN WALLIS:  I'm suggesting that
           since this is critical flow, maybe Professor Schrock
           should see whatever reports are coming out of Purdue. 
           Can you do that?
                       MR. WANG:  Sure.  Right now I have a draft
           report, so I will try to -- but right now we only have
           a draft report, so it's not --
                       CHAIRMAN WALLIS:  So it's a useful time to
           review it.
                       MR. WANG:  Right.  Actually, I try to get
           it to you as soon as possible.
                       MS. UHLE:  We'll give that to you.
                       MR. WANG:  And the flow instability, it's
           planned for this year and next year.  Why we do that
           is because we saw some flow instabilities for the
           operating PWRs and also for the AP600.  Small break
           LOCA we noticed there's a lot of flow instability. 
           And we would like to get some data to assess TRAC-M.
                       For advanced BWR based on natural
           circulation, for example, like SBWR.  And this --
           based on natural circulation pressure is more prone to
           instability, especially during start up because
           there's no forced flow which you have a -- if you have
           forced flow, you reduce a chance to have instability. 
           And flow is determined by natural circulation and void
           fraction.  And the power affected also by the
           fraction, as I've said, some feedback and there's some
           strong covering.
                       And for the largest scale experiment which
           takes data from simulated material is not available
           and the effect of void fraction, feedback and also
           time lag for this -- convection time lag is not
           studied -- that is our objective to try to --
                       CHAIRMAN WALLIS:  PUMA isn't a nuclear
           facility, is it?
                       MR. WANG:  It is not, but we try --
                       CHAIRMAN WALLIS:  How do you do void
           reactivity power --
                       MR. WANG:  We try to use some parametrical
           studies.  For example, we can measure inside the core,
           we can measure the void fraction and from the void
           fraction, we can use our kinetics code to get some --
           the power feedback on the zed power.
                       CHAIRMAN WALLIS:  Can you program the
           power to reflect the void?
                       MR. WANG:  Yes.  And for time lag also we
           do similar trick.  Say, for this use electrical rod. 
           It's not nuclear power and the time lag, they will be
           different, but we will try to find out from the
           nuclear fuel and for the time lag how much, then we
           will try to control the electrical power to delay the
                       CHAIRMAN WALLIS:  So electrical power was
           a shorter time response --
                       MR. WANG:  Right, it's much shorter.
                       CHAIRMAN WALLIS:  -- so you could program
                       MR. WANG:  Try to delay some certain
           amount so that it could match the feedback.
                       And this is basically our objective to try
           to obtain some instability data from this larger
           facility at the low pressure and also obtains
           experiment data for BWR and low point when reactivity
           you have a feedback.  And evaluate TRAC-M for the
           ability to predict three different types of
           instabilities like density wave, flow excursion and
           the flashing-induced instabilities.
                       And also try to see the accuracy of
           prediction based on stability boundary and amplitude
           and frequency.  And the ability to model effects of
           neutronics and thermal conduction time lag on
                       And where we thought -- just a summary.  
                       MEMBER LEITCH:  How do you get low
           instability with power feedback.  I thought it was the
           power feedback that basically led the PWR into an
           unstable situation?
                       MR. WANG:  Basically in say we cover
           constant power.  And if it's a perfect steady state
           it's fine.  But if you have some perturbation for the
           inlet velocity, then instability can occur with
           certain geometries.  For example, like density wave,
           if you have some inlet velocity perturbation, then the
           boiling lengths will be changed.  If the boiling
           lengths has changed, then there's a pressure drop
           across the channel because a two-phase flow in a
           single phase pressure drop it's kind of automated and
           it contains.  And that effect can propagate into the
           system if system just have like out of phase and you
           have density wave --
                       CHAIRMAN WALLIS:  I think if you change
           the words a bit, if you said data on BWR transient
           flow response, but you could sort of vary something
           and then look at the transient response. It doesn't
           have to be unstable just strictly to produce a
           transient response which could then lead to
           instability when coupled.  It doesn't have to be
           unstable for you to measure these kind of times in
                       MR. WANG:  And basically I just revealed--
           actually I have a summary --
                       CHAIRMAN WALLIS:  Does this feed into a
           summary of regulatory response to say BWR, how it
                       MS. UHLE:  Yes.
                       MR. BAJOREK:  It's part of the synergy
                       CHAIRMAN WALLIS:  Part of the synergy
           program.  We'll find out two years later whether or
           not we made the right decision on it.
                       MR. BAJOREK:  According to General
           Electric they stay away from those regimes where they
           would get these instabilities.
                       CHAIRMAN WALLIS:  According to General
           Electric there's no problem at all.
                       MR. WANG:  Well, in summary, for the
           inflow instability -- actually we only can say the
           status -- right now we have done some analytical study
           and basically found out we have to reduce some
           payloads in the inlet in order to have some
           instability.  And that is where we are, and we will
           start to do our experiment very soon.
                       CHAIRMAN WALLIS:  Thank you.  Stole your
           mic?  I guess you'll have to speed up again.
                       MR. BAJOREK:  Okay.  The way I think I'm
           going to do that is by not spending a whole lot time
           on the rod bundle heat transfer project.
                       Joe talked this morning about the type of
           data that we hope to get out of the facility.  Just by
           way of background, the facility itself is full height,
           very well instrumented, essentially a 7 x 7 bundle
           with the corner rods knocked out for a total of 45
                       The rods are protypical, not only in
           length but also in diameter.
                       An interesting feature about the rods. 
           I'm sorry.
                       CHAIRMAN WALLIS:  Well, I guess we've seen
           a lot about this before.  The question's always been
           when we going to get some results?
                       MR. BAJOREK:  The results we hope are
           going to be coming in later in spring, early summer
           this year.  
                       As I mentioned, most of the work that had
           been done at Penn State this year has basically been
           in bundle construction, shaking down the facility,
           putting in supply tanks, putting in the DC power
           supplies.  Their schedule right now is to begin
           testing in, I believe, April of this year. They're
           going to start with a battery of about 15 tests. 
           Those will be reflood tests and then continue further
           on in the year looking at steam cooling tests and then
           tests where there would be steam and droplets injected
           at the bottom of the bundle.
                       CHAIRMAN WALLIS:  My concern has been this
           is an expensive long term program that someone's going
           to cut the budget before it gives you any data at all.
                       MS. UHLE:  We will be finishing our
           reflood data, the first phase at any rate, by the end
           of this calendar year.
                       MR. BAJOREK:  It should be January.
                       MS. UHLE:  Right.
                       CHAIRMAN WALLIS:  It would be good,
           though, to start showing some results as soon as you
           can so that you can show that the program --
                       MR. BAJOREK:  That's why I guess the
           reflood tests are going to be up there first.  Try to
           get the most important information and then build
           things later on.
                       MS. UHLE:  We're also in the discussion
           with Korea to extend the program with some of their
           grid spacer designs in a collaborative effort to
           extend the program to get even more data.
                       MEMBER SCHROCK:  So does this imply that
           pressurization problems will have been resolved?
                       MS. UHLE:  Yes.
                       MEMBER SCHROCK:  Yes.
                       MR. BAJOREK:  Okay.  The next facility
           that I want to talk about is the ATLATS for the phase
           separation.  But kind of as a lead-in to that and the
           problems that we're observing in the ATLATS, I want to
           put that in light with what we're seeing from the
                       As I mentioned earlier, one of the big
           differences in the AP1000 compared to the AP600 is the
           very large increase in the total core power.  We're
           going to see much large superficial velocities at
           anytime during the transients that we observe in the
                       They've changed the resistance of the ADS-
           4 line, greatly reducing the resistance.  They've also
           reduced the resistance of the CMT.  They made some
           other changes to the PRHR.  But primarily with respect
           to entrainment processes, it's been the increase in
           core power that's really going to drive things.
                       As I mentioned, we have been doing some
           scaling evaluation from a top-down scaling
           perspective.  Westinghouse doesn't have too bad of a
           story.  Actually what they've done in the AP1000 by
           increasing the ADS-4 valve, they've made it look
           actually a little bit more like the SPES facility.  So
           when you look at the scaling parameters early on, it's
           even better agreement with SPES, which they have used
           for code validation, than the AP600.
                       Later on it still looks very much like
           APEX in the OSU tests, not too far off. Critical
           period where we're having some heartburn showing from
           a top-down scaling perspective whether OSU is okay is
           during this ADS-4 period.  Part of the question comes
           into what is the critical flow, as the pressure
           decreases, what's the quality that leaves the ADS-4
                       One of the issues that is definitely going
           to be -- have to be taken up in the phase 3, however,
           are items that come from a bottom-up scaling.  Well a
           bottom-up scaling looking at more localized processes
           in the core, steam generator, where else in the
                       Where we see problems right now from the
           scaling leads us again to look at phase separation at
           the hot leg leading to the branch line.
                       These figures don't show up very well, but
           the situation we feel that is going to become even
           more important in the AP1000 than it was in the AP600
           is this condition where we have a froth going up into
           the hot leg and we're entraining some fraction of that
           into the branch line and out.  Now, this factors back
           to the safety of the system and in the analysis,
           because if we start to entrain large amounts of fluid,
           you get a larger two phase pressure drop and that
           delays the time at which you transition over -- excuse
           me, drop to a low enough pressure that your IRWST can
           begin to inject into the system.  The question mark if
           that period probe is too prolonged and you have too
           high an entrainment, too high a boil off, you lead to
           some part of core uncover.
                       The second question that is arising from
           our bottom-up scaling is what goes on in this type of
           a scenario where it might be a DVI line break?  You
           don't necessarily have a level pushed up into the hot
           leg, but now we have a high-quality froth above the
           core.  The question is how much of that becomes
           entrained in the gas flow, eventually up and out the
           branch line.
                       Now, I think everybody remembers seeing
           some of the test results in the ATLATS facility back
           in July.  And by way of background, the basic reason
           for having the ATLATS arose from some of the AP600
           beyond design basis tests that had been run which
           showed that there was some core dryout when they
           started with a lower inventory in the vessel.  The
           RELAP couldn't predict that.
                       We have a situation where we're showing
           hints of core uncover, the codes aren't predicting it
           and we know it was due, primarily, to not being able
           to predict entrainment in RELAP.
                       Now, we saw the facility, saw some of the
           some film clips and also saw how the facility behaved
           in July.  And the meeting, unfortunately or
           fortunately, noted that, hey, there's some significant
           problems with the facility.
                       First and foremost, they're system-
           dependent oscillations.  It seemed to make a very
           large difference depending on whether they have
           blocked off at the steam generator, have a line open
           from the steam generator back to the top of the upper
           plenum.  Other comments that we have received at the
           meeting is that there was an inappropriate use of the
           previous data and existing correlations in their most
           recent model development.
                       The model that they were developing seemed
           to assume some type of an annular ring around the
           bottom of the branch line.  This was the physical
           picture that was being used to develop a newer model
           for onset branch line quality.  
                       And, Dr. Schrock, you have made a number
           of comments on the references that they were
           incorrect.  Previous comments have not been
           incorporated.  And that their use of this person's
           data and this person's correlation was at least very
           confusing, misleading and probably wrong.
                       CHAIRMAN WALLIS:  This just doesn't just
           affect the entrainment, it affects behavior of ADS-4. 
           In ADS-4, the choke flow, you sometimes see steam,
           sometimes you see it very wet or even a slug of liquid
           coming along, that changes the flow rate out of ADS-4
           to the entrainment, and you can set up conciliatory
           behavior.  You may need to be able to model
           conciliatory behavior, not just some average.  I'm not
           sure they're doing that.
                       MR. BAJOREK:  No.  What I want to go over
           are the types of things that we've started to do since
           that meeting.  I'm sorry.
                       MEMBER SCHROCK:  No, finish what you were
           saying.  I'm ready to comment further on the summary
           of what we learned from that meeting in July.
                       MR. BAJOREK:  Okay.  
                       MEMBER SCHROCK:  Are you done?
                       MR. BAJOREK:  Well, I was going to go into
           the things that we're going to be doing with the
           facility and the things that we're going to try to do
                       MEMBER SCHROCK:  In terms of the answering
           Dr. Wallis.
                       MR. BAJOREK:  I'm sorry, I'm not sure what
           you're asking right now.
                       MEMBER SCHROCK:  Well, what I'm trying to
           make a comment on is this summary of the things that
           you found to be significant problems in the old
           facility as a result of the meeting in July.  There
           are, in my mind, important aspects of that that are
           not reflected in this statement.  One of them is the
           fact that the code attempts to solve the problem by
           saying it knows what the flow regime is.  When the
           flow regime is satisfied there's a potential for
           entrainment of liquid in the branch line.  For that to
           be a reasonable proposition, you have to see that in
           the experiment, in fact, you get stratified flow.  In
           that experiment you did not get stratified flow.  You
           had a sloshing back and forth.
                       MR. BAJOREK:  That's certainly correct.
                       MEMBER SCHROCK:  No stratified flow
           evident, and therefore that's the number one question
           I think to be addressed, is your problem in running
           RELAP, TRAC -- whatever code it may be that you're
           trying to do the calculation with it --is the
           difficulty that you have the flow regime wrong or is
           the difficulty something about the model that you use
           if the flow regime is right?
                       MS. UHLE:  Can I answer it?
                       MEMBER SCHROCK:  So that you haven't
           addressed that issue, and I think that's step number
           one in coming to grips with how you're going to get
           something out of the OSU facility that will solve your
                       MS. UHLE:  Can I answer at this point, at
           least, do you mind?
                       MR. BAJOREK:  Go ahead.  Go ahead.
                       MS. UHLE:  Okay.  I think what was shown
           to you at the OSU facility was the goals of the
           facility was to look at essentially each flow regime,
           first starting with the horizontally stratified and
           going into the intermittent regimes as well.  And what
           the movie that was shown to you was looking more at
           the intermittent.  And we have data from --
                       MEMBER SCHROCK:  Well, we weren't looking
           at a movie, we were watching what was happening in the
                       MS. UHLE:  Well, okay. I wasn't there. So
           you saw not a movie, but the real facility.
                       That was for an intermittent regime.  We
           do run in horizontally stratified mode.  And there was
           date taken for the horizontally stratified.  I don't
           think that was communicated to you because it was
           Research's goal to develop phase separation models
           spanning all flow regime and horizonal pipes.  
                       And the reason why we looked at -- or the
           first attempt was to see if we could, regardless of
           flow regime, come up with a correlation that just
           looked at, say, average level and superficial
           velocities was because of exactly what you're saying. 
           That the code, if you took this model and you applied
           it across all different flow regimes, the answer you
           would get would be dependent on what code you're using
           and its prediction of flow regime.  And so they tried
           to come up with factors such as average level
           superficial velocities regardless of flow regime to
           come up with your entrainment rate.  And that didn't
           pan out.
                       So what will happen now is we will,
           unfortunately, have to rely on the fact that you know
           your flow regime and take the data and make sure that
           we are consistently determining the flow regime for
           the horizontally stratified case as well as the
           intermittent, the wavy.
                       MEMBER SCHROCK:  The flow regime that we
           saw was -- the flow condition which is not described
           by the flow regime maps.
                       MR. BAJOREK:  I think your basic question
           is okay, you have this condition in the facility.  The
           flow regime maps and the code right now, and for at
           least the next several years, are static.  They cannot
           track waves or track the development and change of one
           flow regime down a pipe.  In the long run, we would
           hope we would hope that we would get that type of
           thing out of the Purdue or, actually more appropriate,
           the interfacial area transport being done out of
           University of Wisconsin.
                       For right now we're kind of stuck with
           regimes we have.
                       MS. UHLE:  And they are looking at the
           fact that they were getting reflection from the steam
           generator side and getting rid of that to run the
           intermittent tests, you know, getting a flow regime
           that is not --
                       CHAIRMAN WALLIS:  It maybe required that
           you ask them to develop a general correlation
           entrainment out of the branch but using a geometry
           that looks like AP1000.  Because if you had a long
           pipe instead of just try to find a flow in the other
           branch, you might get something completely different
           at what you see.  Maybe you ought to be focusing more
           on what actually happens in something which simulates
           AP1000, therefore results might be at least useful for
           analyzing AP1000.  Don't claim this is some sort of
           scientific study of a branch pipe under other
                       MS. UHLE:  But it's not just protypically
           AP1000.  I mean, in some ways PWR or hot leg
           pressurizer. I mean, there are a few LODs down from
           the --
                       CHAIRMAN WALLIS:  How many LODs do you
           actually get? Maybe you could analyze that, what will
           actually really happen, get a good correlation in
           terms of models of what really happened and not try to
           mix in almost for something else, with 1000 --
                       MS. UHLE:  But in a reactor, I mean you're
           typically more fully developed. So the point of having
           a really long, horizontally stratified regime, there's
           no place in the reactor that you ever would be fully
                       CHAIRMAN WALLIS:  Right.
                       MS. UHLE:  Right. So we're trying to
           identify the horizontally stratified in a sense that
           as horizontally stratified as you can get in a
           protypic reactor geometry.  You know, that's the hard
                       MEMBER SCHROCK:  Well, what we saw in
           Oregon was explained to us as the experiment that was
           used to produce conclusions about the containment
           problem and in fact the level shown as a level which
           is determined by reducing the flow rate until it
           ceased to have liquid entrainment.
                       MS. UHLE:  And then they came back up in
           the other direction and it mismatched.
                       MEMBER SCHROCK:  I didn't see any coming
           back up in the other direction.  I asked about it and
           there was no answer at that time.  Maybe those came
           after that question was asked; I'm not sure.  But I
           think -- what I'm reading here doesn't convince me
           that you have a clear picture yet of sorting out what
           you're going to have to do to get useful information
           out of the OSU experiment. 
                       CHAIRMAN WALLIS:  I think that will
           probably be in the conclusion.  Sometime we're going
           to summarize.
                       MR. BAJOREK:  Well, let me go through and
           summarize the actions as we see them right now.
                       CHAIRMAN WALLIS:  The pictures you're
           showing here of these double bumps -- that's not what
                       MR. BAJOREK:  No.  No.  No, that's --
                       CHAIRMAN WALLIS:  That's a fantasy?
                       MR. BAJOREK:  No.  And I mean it certainly
           wasn't what we saw in the facility.  But we think that
           the goal one on this --
                       CHAIRMAN WALLIS:  It's an analyzable
           situation, but not relevant.
                       MR. BAJOREK:  -- We think the first thing
           is the basic, we're going to try to better understand
           the system oscillations.  The question is these
           oscillations as we see in ATLATS facility, do they
           also occur in the APEX facility, and how transferrable
           is the information that we're getting from ATLATS to
           the full-scale AP1000?  The scaling that was done for
           ATLATS, as well as for the OSU hot leg and branch
           line, were based upon having the right void fraction
           in the upper plenum, the right L over D between the
           upper plenum and the branch line, and the correct
           capital D to small d ratio between the branch line. 
           It really did not look at anything on the length
           between the branch line and the steam generator, size
           and heights of the waves that might form in a pipe of
           diameter D.
                       What we would like to do is to try to
           understand that better to realize whether the waves as
           we see them at ATLATS are also going to occur in the
           larger scale facility.  That would be a review of the
           scaling criteria.
                       Now, we did take Dr. Wallis' suggestion
           and asked them to run a series of tests in which they
           injected into the top and this figure shows what had
           been intended to be porous injectors to go into the
           core -- it doesn't show up very well at all.  But it
           does have an auxiliary air port by which we an do
           injection into the top of the facility.
                       They ran those tests, they sent those to
           us earlier in the month.  We haven't had a chance to
           go through those in great amount of detail, however my
           observation in taking a look and plotting the liquid
           levels, there still are a very high amount of
           oscillations.  It does not appear as to whether that
           smoothed things out.
                       We've since gone back to them and asked us
           based on those oscillations what are some of your
           averaging procedures?  Because we see a lumping of
           much of this data, some of which Jennifer noted was
           horizontal stratified.  If we had those movies, I
           think we'd be able to see that.  A lot of it was
                       We think at this point we need to start
           segregating that data into information which was truly
           horizontal stratified and something that it is
           intermittent, wavy, what other type of flow regime
           that was apparent.
                       In future work we're going to request that
           they supply a CCD or some other recording of what that
           flow pattern was.  Our expectation and understanding
           going into the meeting is that we were going to see a
           lot of horizonal stratified flow.  We'd like to try to
           get that recorded in addition to the comments that
           they do have in the test reports. You have to dig to
           find them, but there is a visual observation on what
           that is.  We'd like to start with that and segregate
           out the points and get them into their appropriate
           regimes right now.
                       CHAIRMAN WALLIS:  Just want to make a
           point that joining of the hot leg and the vessel is
           accomplished by intersecting two cylinders leaving you
           with a sort of strange, sharp edge around that
           opening.  That doesn't exist in the plant.  It could
           be of some significance in the hydrodynamics that
           you're looking at here.
                       MR. BAJOREK:  Okay.  With respect to the
           references and their use of the data, we've also asked
           them to supply all copies of the references that
           they've been using in assimilating their report and
           plan to ask them to rewrite that section where they
           talked about their literature search.
                       Based on the information we got, we agree
           with you that it's confusing and misleading the way
           things have been lumped together.  Some of the reports
           are difficult to get.  We've asked that they supply
           them to us. We're going to do our own review.
                       We feel that the model development needs
           to be revised to be more regime-dependent.  If we can
           some day lump everything together, that would be the
           simplest thing for the code application. But based on
           what we've seen, we should use the horizontal
           stratified data, keep that with models which are
           appropriate for horizontal stratified flow regimes.
                       This in your ring picture that seems to
           have been used in their development certainly didn't
           show up in the experiments.  And what we would prefer
           is, rather than this figure over on the right which
           they assumed, go to a picture which a similar model
           had been devised by, I think it was Yanamoto, where
           the picture, physical picture of the fluid beneath the
           branch line is something that is forming more a
           conical or a pyramid shape.  At least that physical
           picture looks -- corresponds much closer to what we --
                       CHAIRMAN WALLIS:  But if you have a photo
           that looks like a sketch?
                       MR. BAJOREK:  There is one in the report.
                       CHAIRMAN WALLIS:  We found a situation
           where at least at the moment it looked like that
                       MR. BAJOREK:  In fact, it was interesting
           how they did it.  They must have had a boroscope
           inside the pipe looking axially.  And you can see
           almost a formation of a water spout.
                       CHAIRMAN WALLIS:  Well, maybe it does for
           some regimes, but what we remember very much was
           large-scale oscillation of the whole pipe. 
                       MR. BAJOREK:  Yes.  Yes. In fact, the
           oscillation was between the branch line and the steam
                       CHAIRMAN WALLIS:  Okay.  We have to move
           on to the next one.
                       MR. BAJOREK:  Okay.
                       CHAIRMAN WALLIS:  And then you can 15
           minutes of summing up or so.
                       MR. BAJOREK:  Okay.  Subcooled boiling is
           work that is going on at UCLA.  We had Professor Dhir
           come and present his results to us about 3 or 4 weeks
                       Now, the work that's being done at UCLA is
           also in response to AP600 and AP1000, where there's a
           realization that most of the decay heat removal is now
           going to be done at lower pressure.  We feel that the
           models for subcooled boiling would not be as good at
           the lower pressures as they were at higher pressures,
           typically where you would need them for small break
                       The other question that's going to be
           answered by the UCLA work is the idea of heat flux
           splitting.  How much of the energy and subcooled
           boiling goes into void generation versus sensible
           heating of the liquid?  Right now whether it be in
           TRAC or RELAP, the models are largely ad hoc.  Based
           on some limited test data to come up with the models,
           but nothing very mechanistic in the way its treatment
           of this heat flux split.  So the objective of the UCLA
           work, very much like the Penn State for dispersal of
           film boiling, used advanced instrumentation and
           detailed facilities to get high-quality information by
           which we can develop these mechanistic models.
                       MEMBER SCHROCK:  I don't know if you read
           the comments that I made in a recent report, but my
           recollection was in reviewing the -- TRAC's
           documentation back in 1987 was that they had heat
           transfer directly from the wall to the vapor, and
           cases where the wall was -- the flow regime map let
           it.  So the transfer is nonphysical.  It has to be to
           the liquid and then to the vapor.  
                       So I think it would be useful if this
           could get sorted out in the way this was being
           described and state more clearly what this heat flux
           splitting is all about, and the way it's used in the
           code.  It originated the subcooled boiling models and
           that got massaged and massaged and massaged and came
           out as a GE thing under Leahy's name.  But I think
           that a lot of people have had confusion about what
           this heat flux splitting means.  And I think most of
           those people have been people who work with codes, not
           the people with experience.  It needs to be dealt
                       MR. BAJOREK:  Well, I think there's the
           physical models, and I think what you're pointing to
           there's -- a lot of times the code -- you look at the
           hydrodynamics and you pick your flow regime on one set
           of conditions and then you take the wall temperatures
           and maybe some gross estimate of a void and say this
           is what's going on near the wall.  But those physical
           pictures may not necessary correspond.  You may
           predict a bubbly flow, who knows whether the bubbles
           are concentrated out in the fluid or close to the
           wall.  Those selections have to be consistent --
                       MEMBER SCHROCK:  For heat to be
           transferred from the wall to the vapor, you have to
           have a dry wall.
                       MS. UHLE:  Right.  But see, we have this
           problem --
                       MEMBER SCHROCK:  In the physical work.
                       MS. UHLE:  But in the problem of numerics
           if we're taking one second time steps, you can't do
           that because you would get way too much super heating
           of the liquid.  And you can't get around that.  So
           that's where some measure of realizing that you're in
           a numerical system in some way differs from reality,
           and that's why you have to rely on assessment.
                       MR. KELLY:  May I make interjection? This
           is Joe Kelly from Research.
                       What Professor Schrock is alluding to goes
           way back, in forced convection flow they did things
           like void fraction volume --
                       MS. UHLE:  Not necessarily.  That's what
           I'm trying to say is the fact that if you're taking
           over a period of a time step of a second, you can't
           put all of the liquid, all of the heat flux into the
           liquid.  And you know currently in our numeric systems
           or numeric schemes and we would have too much super
           heat the liquid and then the next time step you would
           get the interfacial heat transfer to the vapor.  I
           mean, that's all I'm trying to say is that whether--
           how we solve this problem we can talk about later, but
           why it was done in the past, it may sound weird to you
           but a lot of it is simply because we had to work in
           the numerics of the time.  Now when we make the code
           more implicit, then we can get rid of those things. 
           But the computer limitations in the past prevented
           that because we just didn't have enough memory or
           speed of the computers were too slow.
                       CHAIRMAN WALLIS:  I think that again we're
           getting into too much detail.  If we're going to
           review Professor Dhir's work, we're going to have to
           spend a whole afternoon.
                       MR. BAJOREK:  Well, it would take quite a
           bit of time.
                       CHAIRMAN WALLIS:  There's no way that we
           can get an overview of these programs beginning at
           that level.  What I get from this is that there is a
           problem with predicting the amount of voids you get
           and the heat flux in subcooled boiling --
                       MR. BAJOREK:  Yes.
                       CHAIRMAN WALLIS:  And that probably
           sometime during the year we may need to look at this
           in more detail.
                       MR. BAJOREK:  Yes.  I think sometime in
           probably the spring would be the right time.  
                       CHAIRMAN WALLIS:  I don't recall actually
           having a presentation.
                       MS. UHLE:  It came to the staff.
                       CHAIRMAN WALLIS:  Well, maybe that's where
           we could contribute.
                       MR. BAJOREK:   To summarize what he is
           working on.  Breaking up the wall into several
           components using high speed visualizations.  Two
           different test sections, one a rod bundle another a
           flat plate test section.  Flat plate in order to give
           him things like nucleation site densities, motion of
           the bubbles, collapse rate of the bubbles as they
           leave the wall and then getting additional information
           from the rod bundle to augment that.
                       I've left in the package the types of
           measurements that are being obtained in the facility.
                       I'm going to jump to more conclusion,
           closer to the conclusions.
                       He's been successful at developing a model
           to predict the delta T at the onset of nucleate
           boiling in a subcooled flow, that seems to do a pretty
           decent job at predicting not only his own data, but a
           fairly substantial set of data that he also obtained
           in a literature search.
                       CHAIRMAN WALLIS:  Your measure of success,
           this sort of a picture?
                       MR. BAJOREK:  Well, this would be one of
           them.  I mean, because he's trying to get the onset
           correct.  He's also trying to get the right heat flux
           at the onset correct, simultaneously.  Get the single
           phase heat transfer coefficients and also be able to
           get models for the bubble size and the rate of
           collapse of those bubbles.  It basically gives you the
           condensation component of that split.
                       This shows the heat flux based on his
           model to try to predict the heat flux, which is a
           contribution of a partial subset of those terms, and
           by in large it seems to do a successful job not only
           of his data but also on other sets of data.
                       CHAIRMAN WALLIS:  Could you give us time
           to see what the state of the art was before he came
           along, and if he drew a picture like this based on
           whatever you were using before, is this an
                       MR. BAJOREK:  Yes, it would.  I mean, he's
           also done the comparisons to some previous models and
           you can see where the scatter is significantly larger.
                       MS. UHLE:  Joe Kelly has a good paper on
           the subcooled boiling model if you'd like to see the
           current state of the art.
                       MR. BAJOREK:  Okay. Now where he's going
           with this work now, he's gotten enough data on the
           flat plate test section.  Most of the work that's
           going to be done in 2002 is to try to come up with a
           better term for this flux split, to get the additional
           terms in this heat flux contribution to the total heat
           flux during subcooled boiling, expand the data base,
           getting additional information for the rod bundle,
           increase the range of subcooling and look at some
           higher pressures.  Right now everything is fairly
           close to atmospheric.  
                       I think he can take the facility up to
           close to 3 or 5 bars.  And he thinks that most of that
           work can be completed in 2002, which is why in the
           overall schedule we're looking at trying to implement
           those models later in 2002, but probably not in time
           to get into the Rev 0.1 release.
                       Okay.  The last topic that we're going to
           have is looking at the interfacial transport, which
           has been done primarily at Purdue and University of
           Wisconsin.  Jennifer's going to talk about that.
                       MR. BOEHNERT:  Do we have these slides,
                       MS. UHLE:  No, I'll get them.  Because I
           thought that Steve had them, he thought I had them.
                       I've talked about this before at the ACRS
           meeting, so the objective of the interfacial area work
           is to get away from the static flow regime use in the
           code, the reason being is that for one thing, we need
           to use interfacial area in the code. It's a value that
           we have to have a closure relation for. It determines
           the interfacial heat transfer as well as the
           interfacial drag.
                       We currently model it using static flow
           regimes. I think everyone's aware of the fact that the
           flow regimes were developed in steady state
           situations, lots of air/water. At any rate, the
           transition criteria and the use of the static flow
           regime, it doesn't represent the actual physical
           processes of creation and the destruction of the
           interfacial area, so there's no time and length scale. 
           And so if you change your flow rate; in some sense if
           you have an oscillation you instantaneously change
           your flow regime.  That doesn't sound that bad, but if
           you consider the situation of annular flow and you
           increase your vapor flow rate so that it's beyond the
           point where you're entraining liquid drops, you can
           increase by several orders of magnitude the drag in
           the interfacial area of interfacial heat transfer so
           that it causes this oscillation and it can also cause
           some inaccurate answers.
                       So we're trying to develop a first order
           equation for the transport of the interfacial area;
           that is the objective.  We realize --
                       MEMBER KRESS:  If you have that, you no
           longer need flow regimes at all?
                       MS. UHLE:  That is the goal, but before we
           can take out the flow regimes we have to have the data
           in the model covering all flow regimes in geometries
           prototypical of nuclear power plants.  And that is the
           big effort.  That's why we're trying to collaborate
           with France and Japan, and open this up for
           international collaboration, so it's a big scope.  We
           are making progress ourselves but we realize that we
           had originally thought that Japan and France were
           going to provide the steam water.  We're still working
           on that.
           MEMBER KRESS:  What is the position now?
           MS. UHLE:  I can go through where we currently are. 
           I just want to point out, though, if we don't to the
           point where we actually do use this interfacial area
           transport equation for the flow regimes, this project
           is not useless by any stretch of the imagination
           because of the fact that we do use values for
           interfacial area.
                       We will be able to take these measured
           quantities of interfacial area and then compare them
           to the correlations that we use in the code currently
           to make sure that we are at least getting a prototypic
           value of interfacial area for the flow regime of
                       So, again, if the modeling doesn't work
           out in the long run, the data is still useful.
                       CHAIRMAN WALLIS:  This principle has a
           separate conservation equation --
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  It's something you can
           could put into your TRAC now --
                       MS. UHLE:  Yes, I did that.  Yes, I did
           that.  If you remember a couple of years ago where I
           put in the first or I put in the -- one group
           interfacial area equation. In other words, it was for
           bubbly flow.  So by one group I mean that the vapor
           phase was all spherical, and therefore the drag
           coefficients were, again, first spherical
           configuration.  And in --
                       CHAIRMAN WALLIS:  So how long did it take
           you to do --  a long time?
                       MS. UHLE:  Yes, it took me a week.  It
           took me a week, and that includes modeling and
           comparing to the data, although I did call our
           numerics guru for a few challenges along the way.
                       CHAIRMAN WALLIS:  You called this TRAC-M
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS: And the thing is if 
           these guys are successful --
                       MS. UHLE:  It'll go in easily.
                       CHAIRMAN WALLIS:  -- in 2004 or something,
           put into TRAC as an implement?
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  With an option or
                       MS. UHLE:  Right.  Now with the two group,
           it's going to take me more than a week.  I was going
           to do it this year, but then I said I was demoted to
           assistant branch chief and they don't let me touch the
           code anymore.  But I was planning on doing that to put
           in the two group equation.  And there's a little bit
           more complexity with the two group equation, because
           you do have to solve a matrix.
                       CHAIRMAN WALLIS:  All you have to do is
           delegate somebody younger and quicker.
                       MS. UHLE:  I thought it was older and
                       PARTICIPANT:  That's his answer why we
           hire lower grades --
                       CHAIRMAN WALLIS:  I'm not sure we need to
           spend on this.  It's going on it's processing --
                       MS. UHLE:  It's going on.  We're covering
           flow regimes.  With respect to Professor Schrock's
           questions, we've covered bubbly flow -- sorry.  For
           the co-current upflow we've covered all flow regimes
           up to annular.  We're doing counter current flow. 
           We've completed bubbly flow.  Started to do co-current
           down flow for bubbly flow.  Horizonal, we've covered
           all co-current regimes and we're starting to extend to
           other geometries, so we do have this database and
                       There are two group models that they've
           come up with, although it's not put in the code, they
           do compare to the data as they develop it.
                       In the future, we need to go to steam
           water for the source and sink term of the phase
           change.  And, again, extending to just other flow
           regimes and geometries.
                       We're hoping to have the final model, you
           know, our ideal would be to have it in 2005 in the
           code and replace the static flow regime.  It depends
           a lot on --
                       CHAIRMAN WALLIS:  I hope that they are
           publishing results --
                       MS. UHLE:  Yes. Yes.  You haven't been
           reading International Journal of Heat and Loss
           Transfer then because, yes, we just published
                       CHAIRMAN WALLIS:  You're jumping ahead
           with that accusation.  You don't know what I've been
                       MS. UHLE:  Yes, we've been publishing.
                       Are we done except for the summary?
                       CHAIRMAN WALLIS:  Well, I was hoping that
           we could talk about the papers
                       MS. UHLE:  I can give you the papers, if
           you'd like.
                       MR. BOEHNERT:  Yes, we'd like the papers.
                       CHAIRMAN WALLIS:  I was trying to jot down
           as where we could interact with you in the future that
           would be profitable.  My colleagues should come in on
           this.  But I feel with the development of this
           consolidated code that what we should do is encourage
           you to keep up your enthusiasm for the activity but I
           think where we might contribute is in the
           documentation.  Do you have draft documentation that
           we can look at and give you some input and avoid 
           giving you surprises when we see it later on?  Maybe
           we'll make the documentation better?  I think in the
           other areas of Joe Kelly and company, doing work with
           their former knowledge of what they're doing than we
           are, I think that they go for it and we'd like to see
           the result.  But then I think we should discuss what
           we need to do about each of the review of some of
           these other programs, USU, Penn State.  But can we
           first look at other comments on the TRAC 
                       MEMBER LEITCH:  My question, I guess, or
           comment is that I'm a little confused about what
           release means.  Does that mean that it can only be
           used in certain circumstances?  And if so what
           purposes?  In other words, are there other grounds or
           to what extent -- seeing that we've talked about
           perhaps 8 or 10 applications and I guess what I think
           should be the outcome of the status of this by the end
           of next year.  It would be useful to address these
           other applications.  What will the status be?  In
           other words, I guess we've seen a program that ends
           sometime at least in the next 13 months, but obviously
           the research effort is geared towards the targeted
           applications.  But I'm just a little confused as to
           what will be value of using the TRAC code and the
           RELAP5 in these applications.  I guess that's a
           reasonable question.
                       MS. UHLE:  No, no.  That's a very
           reasonable question, and it's a quick answer here.  Is
           that by the end of 2002 we will be as good as the old
           codes for the targeted applications, so we can from
           then on rely on the TRAC code.
                       Now, the fact that RELAP5 is now the
           workhorse code mostly for the international community
           as well as for NRR, we foresee bringing that in-house
           and maintaining and it using it as a benchmarking tool
           as we continue the effort.  So it's not like we'll be
           dumping RELAP5.  But at that point we'll be able to
           use either code for, say, the PWR applications. We
           will, of course, think that TRAC will be better for
           the large break LOCA for the PWR. 
                       We will be as good as TRAC-B used to be
           for the BWR applications. And we can do stability and
           3-D kinetics for the BWR to replace RAMONA.
                       So, again, we'll be starting to focus and
           start this transition into relying on TRAC-M.
                       MEMBER LEITCH:  The synergistic effects?
                       MS. UHLE:  That will be done with TRAC-M.
                       MEMBER LEITCH:  And the PBMR?
                       MS. UHLE:  TRAC-M.  Right.  But we will by
           the next time we -- we say the next fall meeting, we
           will have the physical models in to do the PBMR. 
           Hopefully, have identified data sources and at least
           have a few plots to show with respect to system
                       MEMBER LEITCH:  I guess just to
           paraphrase, I think what I heard you saying is by the
           end of next year this is when it comes out, TRAC-M
           will be equal to or better than?
                       MS. UHLE:  Yes.
                       MEMBER LEITCH:  So you will make another
           presentation to the committee?
                       MS. UHLE:  Yes.  That is the goal, yes.
                       CHAIRMAN WALLIS:  So you will come to us
           towards the end of next year with a consolidation of
           the codes?
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:   You will then have
           consolidated the codes?
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  Right so you won't have
           improved them much.
                       MS. UHLE:  In some cases, for example, the
           level tracking we've improved.  The large break
           calculations with Joe Kelly and Weidong Wang's reflood
           work, we would have improved.  Hopefully we will have
           the phase separation stratified flow model in for use
           with the AP1000, we would have improved that.
                       The other improvements have been more user
           convenience , speed, robustness rather than physical
           models.  And then at that point in time as we then go
           into more of a PIRT base developmental assessment
           effort and continue working more closely with the test
           programs, we would then focus on improving the
           physics.  But the original charter of the
           consolidation and what the Commission had signed off
           on was to recover capabilities by the end of this
           period, and we feel will achieve that.
                       MEMBER SCHROCK:  Do you have any
           indication that industry wants to start using it?
                       MS. UHLE:  Not so much industry. 
           Industry's interested in the graphical user interface
           because it works with RELAP5.  And, of course, there's
           the strong use of RELAP5 in industry.
                       Shanlai Lu on the staff has for NRR's use
           has taken the TRAC-G and developed a pearl strip that
           allows us to take a TRAC-G input deck and convert it
           into what TRAC-M can run.  So NRR would be using that
           and is a comparison for the future application of the
           TRAC-G submittal for the large break case.
                       The Naval Reactors is very interested in
           using the consolidated code because Betest and Capital
           are looking at, and in fact consolidating their
           analytical work as well.
                       And then, of course, the international
           user group is holding off, you know, waiting to see
           how it works.  Most people are interested in the
           ability to recover RELAP5 functionality, and that is
           what we need to -- we will proving this in a month or
                       MEMBER FORD:  I've got three comments. 
           Not being a fellow hydraulic person and not specific
           to the physics. 
                       First is, you weren't clear about the
           qualification of the code especially when you're
           qualifying it against scattered databases.  Presumably
           the code should be able to predict the uncertainty
           that you have.
                       The second question, and actually more a
           comment.  The second question is what will the
           hierarchy be for the various codes when this TRAC-M
           code versus the licensee's code, what determines
           whether one is better than the other?  Really a
           professional comment.
                       The third one is really also a comment. In
           the beginning that mission statement said safety
           margins and therefore presumably the next stage after
           TRAC-M is to incorporate it into materials
           degradation, and I'd be interested to hear about that. 
           Is that your ultimate goal?
                       MS. UHLE:  I'm Sorry.
                       MEMBER FORD:  Well, aging phenomena of the
                       MS. UHLE:  I mean, our work with the
           materials interaction really is coming from providing
           thermal-hydraulic conditions to the division of
           engineering, and as well as working with the PRA
           branches where we provide, you know, based on the
           material degradation at these new thermal-hydraulic
           conditions, or maybe because of flow induced or flow
           accelerate corrosion you're going to have a higher
           failure -- or sorry.  A higher break frequency, you
           know, that would go into the PRA.  You know, that's
           more of our interaction.
                       MEMBER FORD:  Well, there's a lot of
           material degradation issues when you have a synergy. 
           Presumably that's all been passed along --
                       MS. UHLE:  Typically the level of detail
           you need to couple thermal-hydraulics to something
           like flow accelerated corrosion is not going to come
           out of a system code, because our nodes are like this
           big.  And you're looking at the boundary layer to look
           at, you know, the physical processes going on to do
           the flow accelerated corrosion.  And more --
                       MEMBER FORD:  I see.
                       MS. UHLE:  That would be more a
           computational fluid dynamics linkage.
                       MEMBER FORD:  Perhaps this phenomena is
           related to the core shroud.
                       MS. UHLE:  Again, the idea of the thermal
           fatigue cycling, that again is looking more at large
           eddy simulation to get the frequency of the water
           coming up at a different temperature, going back down. 
           That is not something a system code is ideally suited
           for.  That would be more of a computation fluid
           dynamics application.
                       And we do have CFD technology in-house,
           and we are, again, hiring to increase that and that is
           something that we can think of as far as interacting
           with the division of engineering as these applications
           come up.
                       CHAIRMAN WALLIS:  What I had in mind in
           this summary was we give you some input, and we speak
           again about more activities, say, in six months, and
           how we can interact in the next six months.
                       Tom, did you have -- I think we're talking
           about the TRAC-M --
                       MEMBER KRESS:  Yes.  TRAC-M.  I did have
           a couple comments, but I'm not sure my comments are on
           how best to interact.  My comments are more with
           respect to what Ms. Uhle was saying.  I think you
           ought to view integral experiments as rough.  I don't
           think you're going to predict experimental error. 
           We're talking about two different things.  Go look and
           see if your predictions fall within the boundaries of
           the experimental error.  So my comment there is use
           separate effects testing to determine the
           uncertainties in your specific model.  Think very hard
           about how to incorporate them in the code in a way
           that you get an uncertainty distribution in your final
           product.  When you get to that point, you really have
           a code that is very useful.
                       My other comment I had is that I certainly
           like what I see and I encourage you to continue with
           this.  If you are very successful it would solve a
           whole lot of these problems with flow regimes, how you
           transition from one to the other and how you deal with
           them on the code.  I'd certainly like to hear more
           about that later. 
                       CHAIRMAN WALLIS:  Can we move on then to
           the separate programs?
                       The OSU program, I'm not sure -- any hope
           of bringing them around to our viewpoints?  Why don't
           we try to figure out if there is some way in which we
           can interact.  I don't want to be with you or them at
           the end of the program and have exactly the same
           comments we had when we visited.
                       MS. UHLE:  As part of my action items that
           I have written down, it is to schedule some sort of
           test program review if I can interact with Paul to do
           that. Because, obviously, with your expertise it's of
           good value to us to learn.
                       CHAIRMAN WALLIS:  Right.
                       MS. UHLE:  And I mean I think our goals
           our consistent really, although sometimes it can be a
           combative interaction.  You know, we want an accurate
           code, we want to be able to extend the code to other
           applications easily, we want to be able to understand
           uncertainty and calculate it so that this tool can be
           of use.  You're looking at a whole lot of people that
           have put a lot of time in this program, and the idea
           of it not being useful, you know, we wouldn't get out
           of bed in the morning.
                       So I do think that our goals are
           consistent, and so I think further interaction with
           you on a more frequent basis can only benefit us.
                       CHAIRMAN WALLIS:  Maybe there is a way in
           which OSU can come before this Committee before the
           report to the full assembly.  There's no way.
                       MS. UHLE:  That's --
                       MR. BAJOREK:  No, that was for the ETS.
                       CHAIRMAN WALLIS:  ETS.  The other work is
           still going on?
                       MR. BAJOREK:  The work is --
                       MS. UHLE:  Oh, yes, we're getting a
           preliminary model for the --
                       CHAIRMAN WALLIS:  Work on a useful
           interaction with OSU that we could have.
                       MS. UHLE:  Yes.  Okay.
                       CHAIRMAN WALLIS:  Penn State, it seems
           they're still building the apparatus, they haven't
           gotten their results. I'm not sure we have anything we
           can --
                       MS. UHLE:  I mean, they're doing shakedown
           testing now and characterizing like volumes and lost
           coefficients and things of that nature.
                       CHAIRMAN WALLIS:  And PUMA oscillations,
           I don't think we have anything to get until they start
           doing something?  We might, I think, contribute to the
           critical flow models.
                       MS. UHLE:  Right.  I have down to give you
           that critical flow report for Professor Schrock.
                       CHAIRMAN WALLIS:  And maybe you can evolve
           at some time an actual presentation by them?
                       MS. UHLE:  Yes.
                       CHAIRMAN WALLIS:  And then on DEER,  I
           think we really are due a presentation.  It's been
           going on for some time, we have not had the detailed
           interaction, the kind of questions we'd love to ask
           and don't have time for today, so maybe we should
           schedule something for later.  After the start of the
           year maybe.
                       MR. BOEHNERT:  That'll be fine.
                       CHAIRMAN WALLIS:  All right.  Anything

           else on -- I didn't have anything immediate
                       MR. ROSENTHAL:  You expressed an interest
           in some of the MOX work.
                       MS. UHLE:  MOX work.
                       CHAIRMAN WALLIS:  There is a fuel
           subcommittee of the ACRS.
                       MR. ROSENTHAL:  Yes, I think that will be
           a better place for that and we could advise it --
                       CHAIRMAN WALLIS:  It's all from a drop,
           it's neutronics.
                       MR. ROSENTHAL:  We would do the neutronics
           and other MOX related issues about how you load the
           power and then the source.
                       CHAIRMAN WALLIS:  But we'll do that with
           kind of a separate subcommittee on MOX. Maybe that's
           where it actually --
                       MS. UHLE:  Okay. Yes, I have that down. 
           Although we will give you some written information to
           respond to Professor Schrock's questions.  Although it
           may not be answering all the questions that you've
           asked, that can be at a future time.
                       CHAIRMAN WALLIS:  I think that the purpose
           of this meeting is for us to give some input for the
           main committee and the writing of the research --
                       MR. BOEHNERT:  That's correct.
                       CHAIRMAN WALLIS:  This does not require
           some letter or anything?
                       MR. BOEHNERT:  No, it does not require a
           letter.  It's fed into the work on the research --
                       MS. UHLE:  I mean, one thing I do want to
           point out, because based on the feedback you give us
           annually is that we understand we need to tie in our
           test programs closer.  It's not news to us to hear
                       In the past it's simply been how much time
           we have and the staff we had available.  Now that
           we've been in this hiring mode and we've been bringing
           more expertise in-house, we're going to try to start
           to do that.  It's a big focus for us.
                       CHAIRMAN WALLIS:  I just want to be
                       MS. UHLE:  We realize that, it's not -- in
           fact, you know, Steve being the senior level scientist
           here is the perfect person to really lead that
           initiative, and he's been doing a great job in trying
           to tie in the model development work, the test
           programs more closer to the code development work that
           Joe Kelly will be overseeing.
                       CHAIRMAN WALLIS:  I hate to go back to the
           TRAC thing, but you know you have done a good job of
           consolidating these codes and at the end of this next
           year you're going to show that they'll at least do all
           the things the previous codes did, which is a bit like
           saying Amtraks going to run at least as fast as the
           steam trains used to run in the '30s.  And what we're
           really looking forward to is that there's a high speed
           train or something that's really that much better. 
           That's what we'd love to see.
                       MS. UHLE:  Right.
                       CHAIRMAN WALLIS:  The sooner that can get
           on the track, the better.
                       MS. UHLE:  Yes, right.  Again, we agree
           with that.  Now, we've been doing what management has
           assigned us to do as far as the Commission policy
           being to do the consolidation first before we start
           the improvements. We also want to make improvements,
           probably faster than you do, because we're the ones
           doing the work and it frustrates us more than it
           probably frustrates you.  So that is going to be our
                       But we were tasked with this consolidation
           effort first, and that was the high priority.
                       CHAIRMAN WALLIS:  Even if you have to
           smuggle the improvements along.
                       MS. UHLE:  We've done that.
                       MR. ROSENTHAL:  No, no.  But we work in
           accordance with the operating plan, of course.  But,
           no, in conjunction with the synergy work we have
           planned ATWS calculation and we can now do couples,  
           3-D, space time kinetics, really better ATWS
           calculations than we were able to do.  And that'll be
           a shorter term product.  But we do some benchmark.
                       So we're going to start seeing the
           benefits now.
                       MS. UHLE:  Ready for your next victim?  I
           think they're behind you.
                       CHAIRMAN WALLIS:  I'm very glad that you
           have all these people now to work on these problems. 
           It's good to see Joe Kelly back here.  Go away with a
           good feeling.
                       MS. UHLE:  I also went away with the
           concept that any PIRT that you are involved in we're
           supposed to ignore, because you are unduly prejudice,
           that's the number one lesson we learned today.
                       CHAIRMAN WALLIS:  I think I'm utterly
           clean.  I don't think I've ever been involved in a
           PIRT.  Now nor have I ever been.
                       Do you have a few final remarks?  Then we
           will close this part of the meeting.
                       I would like to take a break.  I notice
           there are all the people waiting.  We have caught up
           some time, so we'll try to keep on time, at least get
           out of here before 6:00.
                       We'll take a break.
                       (Whereupon, at 2:43 off the record until
           2:02 p.m.)
                       CHAIRMAN WALLIS:  No introduction, Mr.
           Henry, please begin.
                       MR. HENRY:  Thank you, Mr. Chairman.
                       We're happy to be here today just to have
           the opportunity to present to you this new activity of
           using the MAAP5 containment code to replace the models
           for containment integrity at both Beaver Valley and
           Point Beach.
                       Before I get into talking about it, I
           thought perhaps you would like to hear from the two
           different sites of their motivation for going to a
           different code for containment integrity, that it has
           some differences which are site specific.  So, maybe
           just a couple of minutes with each site.
                       I'd like to introduce Mike Testa from the
           Beaver Valley site and then he'll be followed by Harv
           Hanneman from Point Beach.
                       MR. TESTA:  My name is Mike Testa.  I'm
           with Fist Energy, and we operate the Beaver Valley
           Power Plants, that's Beaver Valley 1 and 2.  And I'm
           Project Manager for the Power Uprate that's being
           undertaken there.  The power uprate that we're looking
           at for the Beaver Valley plants to increase the power
           in total by about 9.4 percent.
                       The MAAP code and the use of the MAAP code
           is an integral part of that, and I just want to give
           you, as Bob said, a minute or two perspective on the
           use of MAAP at Beaver Valley.
                       The Beaver Valley plants are three loop
           Westinghouse PWRs.  The architect engineer was Stone
           and Webster.  The containments were designed
           subatmospheric, that's the way they're currently
           operated.  And we want to use the MAAP5 computer code,
           basically, to replace the existing design basis
           computer code LOCPIC.  And using the MAAP5 code we
           want to, again, reanalyze the containment and move to
           an atmospheric containment.
                       Benefits for going to an atmospheric
           containment are that right now for personal access to
           the containment, it's in an oxygen deficient
           environment and the people that access the containment
           are required to wear supplemental breathing apparatus. 
           And this will eliminate the need for that.  That goes
           towards enhancing personnel safety on access to the
                       The other thing this does for us is that
           with a move to atmospheric containment where we change
           the initial condition for the containment operating
           pressure, we're incorporating that into our best
           estimate LOCA analysis. And this will allow us to gain
           margin on peak clad temperature, so we'll be gaining
           a benefit in that respect also.
                       And, as I mentioned, this supports our
           power uprate initiative in that the power uprate is
           going to be based on the containment analyses that's
           done with MAAP5.
                       CHAIRMAN WALLIS:  If you do not use MAAP5,
           are you not able to get this 9.4 percent power uprate? 
           Is it critical?
                       MR. TESTA:  Yes, it's critical in that,
           yes, we've done some studies with the existing code
           and with then we looked at MAAP5 and it affords us
           additional benefit in that we can increase the initial
           containment pressure and basically review or rerun the
           design basis spectrum of accidents and stay within our
           containment design pressure.
                       MR. BOEHNERT:  You said you're going to a
           best estimate LOCA code.
                       MR. TESTA:  We're going to use that, yes. 
           Westinghouse best estimate LOCA.
                       MR. BOEHNERT:  Westinghouse?
                       MR. TESTA:  Yes.
                       MR. BOEHNERT:  Have you checked with them?
                       MR. TESTA:  Yes.  Again, our plans for
           MAAP5 is that we're going to utilize it for the
           containment integrity evaluation.  Again, we want to
           replace the LOCPIC code. And in doing this we're going
           to perform the analysis using MAAP5 code consistent
           with the current design basis requirements, and that
           we're going to analyze for LOCA, steam line break,
           different spectrum of breaks and look at the
           corresponding results, the response of the containment
           given pressure temperature and so forth.
                       And the last thing is that, again, the
           MAAP5 takes advantage of the latest experimental
           information.  And what we want to do with MAAP5 is
           move or take the computer code in-house so that we can
           put our engineers in a position to be able to utilize
           the computer code and to make operating assessments. 
           We've been working up to this point with Dr. Henry to
           develop the inputs and the parameter files, which is
           a benefit to our developing our in-house expertise.
                       MEMBER KRESS:  What was your last code
           that you used before?
                       MR. TESTA:  LOCPIC.
                       MEMBER KRESS:  L-O-C?
                       MR. TESTA:  Yes, L-0-C-P-I-C.
                       MR. BOEHNERT:  When are you making these
                       MR. TESTA:  We talked about that yesterday
           a little bit.  There's going to be a topical submitted
           in January time frame for the MAAP5 code and we're
           looking at May for the Beaver Valley plant specific
           submittal.  And in there will be the MAAP5 code, the
           analysis that was conducted, the results and also the
           supporting information on allowing us to move to an
           atmospheric containment.
                       MR. BOEHNERT:  What about the LOCA code,
           when are you going to make these submittals?
                       MR. TESTA:  Well, the LOCA code, that will
           follow. That will be later on in around September time
           frame.  And we're basically putting in the building
           blocks for a power uprate submittal.
                       MEMBER KRESS:  When you use MAAP5, and I
           don't know if this is for you or somebody else, do you
           use it differently?  Do you use other sources also? 
           What do you use as the input?
                       MR. TESTA:  The input of MAAP5 is going to
           be the Westinghouse mass and energy input.
                       MEMBER KRESS:  Okay.  So you use the mass
           and energy input?
                       MR. TESTA:  Yes. Yes. Correct.
                       MEMBER KRESS:  You'll only use the
           containment part in MAAP5?
                       MR. TESTA:  Right.
                       MEMBER KRESS:  Then the NRC would use this
           and they'd never have to check the containment?
                       MR. TESTA:  Correct 
                       MEMBER LEITCH:  Does MAAP5 have the option
           of one region, or five regions?
                       MR. TESTA:  Do you mean as far as
           analyzing or --
                       MEMBER LEITCH:  Yes.
                       MR. TESTA:  Yes. Right now the developed
           model for Beaver Valley is 17 nodes for both Beaver
           Valley 1 and 2.  Basically the same model is broken
           down into 17 nodes and review that for large breaks,
           you know, which nodes or compartments they occur in
           and then we're evaluating the corresponding response
           within the given of the multi-node response capability
           of the code.
                       CHAIRMAN WALLIS:  So how many nodes are in
           this MAAp5 code?
                       MR. TESTA:  Seventeen.
                       CHAIRMAN WALLIS:  How many in your present
                       MR. TESTA:  One.
                       CHAIRMAN WALLIS:  One?
                       MR. TESTA:  Yes.
                       MEMBER LEITCH:  So to get the results
           where the containment pressure is acceptable you not
           only are changing the code but you're increasing the
           number of regions analyzed.
                       MR. TESTA:  Yes, that's part of what Dr.
           Henry's discussion will be is on the benefits or the
           need to incorporate multi-node model.
                       CHAIRMAN WALLIS:  Thank you very much.
                       MR. TESTA:  Thanks.
                       MR. HANNEMAN:  Good afternoon. I'm Harv
           Hanneman.  I work for Nuclear Management Company and
           the Power Uprate Project Manager for Point Beach
           Nuclear Plant.
                       A little background, Point Beach is a two
           unit site with two LOOP Westinghouse reactors, roughly
           1500 megawatts thermal each.  We have large dry
           atmospheric containments for both units. And our
           initial motivation for using the new MAAP5 methodology
           is to support containment integrity analysis for
           possible future power uprate of about 10 percent in
           reactor power.  And we're in the planning phases of
           that project right now, and we saw the need to get
           additional margin for our peak pressure and also
           temperature in containment because of the 10 percent
           higher reactor power.
                       However, other benefits that we expect to
           achieve by the use of MAAP include the accommodating
           a pre-accident containment pressure of 3 psig.  So
           that would be in our technical specifications in the
           range of pressures that would be allowed in
           containment initially.
                       Provides margin for some of the issues on
           containment fan cooler service water boiling, which
           came out of Generic Letter 96-06.
                       And also provides a plant specific main
           steam line break containment analysis for Point Beach.
                       Currently our licensing basis is an
           evaluation of a generic two LOOP Westinghouse analysis
           for containment, so going to the uprate, we thought we
           needed a plant specific analysis and we believe MAAP
           will give us the margin that we need.
                       CHAIRMAN WALLIS:  Does MAAP give you a
           margin for this service water boiling issue?  Does it
           predict containment or something?
                       MR. HANNEMAN:  We expect it to predict
           slightly lower peak temperatures early in the
           accident, and that's when boiling is an issue.
                       CHAIRMAN WALLIS:  Coolant containment?
                       MR. HANNEMAN:  Right.  Right.
                       CHAIRMAN WALLIS:  I understand now.
                       MR. HANNEMAN:  So our application of MAAP
           would be to use MAAP5 for the containment integrity
           analysis for the plant. We would continue to use the
           Westinghouse methodology for calculating the mass and
           energy releases as an input for both LOCA and steam
           line break accidents.  We currently use the
           Westinghouse COCO methodology for containment
           integrity, and we would replace that with the MAAP5.
                       This would allow us to take advantage of
           some of the latest experimental information that Bob
           Henry will be discussing here in a few moments.  And
           it also provides us an opportunity to bring the
           containment integrity analysis in-house so our own
           engineering staff will be performing the plant
           specific calculations; that'll give us greater
           knowledge of that analysis in-house and also allow us
           to perform more timely responses to any operational
           emergent issues that come up with regard to
           containment response.
                       MEMBER LEITCH:  Harv, do you, like Beaver
           Valley, also need to use MAAP5? 
                       MR. HANNEMAN:  We've done some initial
           analysis using the COCO methodology for both LOCA and
           steam line break.  The LOCA peak pressure was slightly
           under our containment design pressure of 60 pounds,
           but the steam line break the pressure exceeded it at
           the uprated condition.  So, that's why we feel we need
           this methodology to give us a little bit more margin.
                       MEMBER LEITCH:  How many nodes are using?
                       MR. HANNEMAN:  I'd have to defer to 10 --
                       MEMBER LEITCH:  Nine.
                       MR. HANNEMAN:  Nine volumetric nodes.  And
           currently we have one also with the COCO.
                       MEMBER LEITCH:  Just a quick aside to
           Mike, the people at Point Beach are talking about an
           initial pressure in pounds, do you have a similar
           number for Beaver Valley?
                       MR. TESTA:  Yes, and for the move to
           atmospheric containment we're looking at developing an
           operating band of 12 to 16 pounds.  One atmosphere for
           us is 14.3
                       MEMBER LEITCH:  Thanks.
                       MR. HENRY:  What I want to present for you
           today is really a work in progress, and we
           particularly wanted to get your feedback on the
           approach.  As you can see, there's a couple of sites,
           that we really want to know how you feel about this
           and what has to be done in the future.  And has been
           said by both of them, there will be a submittal to the
           staff sometime planned early next year and it'll be
           led by a submittal of the methodology itself for the
           staff to begin to review.
                       But in addition to your feedback on the
           methodology, as we go through this you'll see that
           there's a lot of experiments here and the experiments
           represent a level of understanding and the
           capabilities of the calculational tool.  If there's
           some experiments that we haven't managed to cover here
           that you think would be very helpful in understanding
           the capabilities of the model, we also want to get
           that particular feedback and get it early on so that
           we can take advantage of the expertise on this
                       Obviously, I don't have to tell you.  Feel
           free to ask me any questions as we go through this.
           But let me also say early on that there's obviously a
           lot more material than we can cover in the time that's
           allotted. I apologize for that.  We'll go as slow as
           you want to go, but we did want to bring to you the
           fact that we've worked very hard at trying to make
           sure that the model is comprehensive of these
           experiments and in a very simple manner.
                       So, the things that I'd like to cover for
           you today are the issues that are related to:
           nodalization; representation of the atmospheric
           motion, which is circulation within the atmosphere has
           a major influence on the rate of energy transfer from
           the containment atmosphere on a nodal basis to the
                       Let me also say just up front the
           nodalization scheme and map is generalized. You can
           have as many as you want to define.  Right now the
           code will allow you up into the range, of what, I
           think 26 or so.  But usually it's a very highly
           compartmentalized containment that would need 26
           nodes, but that's why there's different nodalization
           schemes for the different plants.  As an example, two
           LOOP versus three LOOP gives us different
           compartments.  Different geometry gives represented
           differently.  But we'll talk about that as we go
           through this.
                       CHAIRMAN WALLIS:  Circulation is going on
           within the nodes?
                       MR. HENRY:  Within each individual node is
           where it's evaluated, yes.
                       CHAIRMAN WALLIS:  Now, I don't quite
           understand that.  So you have some sort of a model and
           it interconnects the hose between the nodes, but it
           also super imposes some kind of a circulation within
           each node?
                       MR. HENRY:  We will get to that.  And the
           place that's important, Graham, is that's what
           dictates what the local boundary layer is and
           therefore, the rate at which energy can be transferred
           to the wall.
                       In addition to this, this blow down and
           give you forced circulation flows, but then you also,
           obviously, have to comprehend natural circulation
           flows because there can be compartments that are
           isolated or there's later in time when the flows die
           down.  Natural circulation dominates.  That has to be
           a key part of it.
                       Another very essential part, which is
           nothing new to MAAP5, that's already in MAAP4, is the
           ability to have countercurrent natural circulation if
           you have heavy over light at an opening between the
           two so that they can exchange mass and energy, and
           that natural convection type phenomena.
                       Condensing heat transfer, of course, we
           look at the condensing on cold heat sinks.  We looked
           very hard at the separate effects test, and that's
           where our understanding comes from.  And we try to
           make that step to the containment analysis in a very
           structured logical manner without any kind of games. 
           So our whole understanding comes from the separate
           effects tests.
                       And then lastly, the influence of water
           entrainment, and that's another place where the local
           circulation velocity is important because we can have
           water films on the walls, we could have water
           accumulate on the floor.  If you have velocity which
           exceed the entrainment rate, then that material could
           be picked up and put into the atmosphere.
                       So from our perspective, as has already
           been discussed, we want to move to something from a
           design basis approach to something which is more
           realistic, and we hope to be very realistic of the
           containment response.
                       And the issues that we see that are
           involved in this are:  
                       Certainly nodalization, because we want to
           represent the containment geometry; 
                       The need to represent the displacement of
           noncondensible gases, and that's a major reason why
           multi-node differs from single node because you can
           displace air out of the region and, of course,
           displace noncondensible gas means that for certain
           conditions at short time frames the energy that's
           transferred to the wall can be much greater.  If you
           have strictly a single node, then the partial pressure
           of the air is always the same;
                       We need to represent the potential for
           induced circulation, which means we solve the momentum
           equation in the gaseous atmosphere as this blowdown
                       And we want to represent the potential for
           stratification, so we look at these nodalization
           schemes.  There's always a potential above the
           operating deck of having more than one more node.  So
           if you have light gases, there is a potential that it
           can accumulate in the top of the dome.
                       MEMBER KRESS:  In read in the material we
           received that there is no momentum equation in that. 
           Did I get that wrong?
                       MR. HENRY:  I think so.  But like I say,
           there's a lot of momentum equations.
                       CHAIRMAN WALLIS:  But they're not
           transient momentum, they're in a pseudo-steady state.
                       MR. HENRY:  Correct.  Transient in the
           sense that you give me the current conditions and
                       CHAIRMAN WALLIS:  It really should be
           momentum DT in there.
                       MR. HENRY:  Yes. Well, for a given cell
           the momentum in a cell -- in a node changes given the
           blowdown time.  Circulation velocity is a function of
           time.  You can ask me the question when we get to it.
           Maybe I'm misrepresenting or misconstruing what you're
                       CHAIRMAN WALLIS:  Well, I think your
           momentum equation does have a D by DT determinate.  It
           just balances.
                       MR. HENRY:  Okay. Well, we'll get to it. 
           For the kind of nodalization schemes that we
           recommend, certainly it's to move away from the single
           node for reasons noted here, but you don't have to
           have tremendous number of nodes.  You just have to
           represent the fact that the air can be moved to
           different locations, that you can have stratification,
                       From our perspective, what it means to
           have a realistic model, and I'm just going to discuss
           both of these points together in time, to save us some
                       We want to make sure that we represent all
           the systems and all the phenomenaology, that have a
           first order effect.  And that's very straight forward. 
           And we want to also represent those which clearly have
           a second order effect, which means that they impact
           things in the order of 10 percent.
                       MEMBER KRESS:  When you say systems, you
           mean things like fan coolers and sprays?
                       MR. HENRY:  Sprays, right.  And, of
           course, the M&E coming out of the break and any
           special things.  If we're looking at another plant,
           like Cook, the dynamics of the ice condenser and its
           melt and drainage, and etcetera.
                       And the things that relate to 10 percent
           that could be issues.  Things like water entrainment
           may either influence things by order of a 100 percent
           or the order of 10 percent.  As we'll see later on,
           both nodalization of water entrainment have a
           significant influence on this.
                       That's our real focus, to make sure that
           we cover all these phenomena, and when you get down
           things which relate to one percent, it's kind of hard
           to deduce what kind of influence they really have and
           then take the jump to full scale containment
           experiments and try to look for that particular
                       CHAIRMAN WALLIS:  The first order is 100
           percent, and you can't have very many of those, can
                       MR. HENRY:  Correct.  Don't have too many. 
           That's where order of magnitude comes in.
                       CHAIRMAN WALLIS:  You said first order was
           30 percent or something, then you could have three of
                       MR. HENRY:  That looks like an argument I
           need to delegate to somebody who is younger and
           quicker, Graham.
                       Okay.  First off, but what's the influence
           of nodalization?  Because that's one of the aspects
           that you just heard that's important to these two
           sites.  They currently are licensed with single node
           models and it gives them some difficulties when they
           take the current design basis in the M&Es and apply it
           to the model.  So is it the limitation of the model or
           is it a limitation of the design?  Well, the only way
           you can figure that out is to do something which has
           more than one node and look at the influence of it.
                       So what we did to just determine the
           influence of moving to a multi-node containment was
           take MAAP and let MAAP produce the M&E.  And so this
           is not coming from a design basis M&E, but it's not
           meant to say this the plant response. All we want to
           look at here is what's the influence of single node
           verses multi-node for a large break LOCA response and
           for main steam line break response.
                       What we have then --
                       CHAIRMAN WALLIS:  What you want to do with
           CFD is you keep applying the nodes until it makes no
           difference.  Here you're showing there is a
           difference, but you don't show -- you keep on going to
           a 100 or 200 or 300 node --
                       MEMBER KRESS:  I think there's a
           difference of what we're calling nodes.  These nodes
           have specific boundaries --
                       CHAIRMAN WALLIS:  A physical basis.
                       MEMBER KRESS:  Yes, physical basis.  Those
           ones you're talking about are kind of different. 
           There's a difference, I think.
                       MR. HENRY:  And you're also taking away
           any information I could use if you guys say come talk
           to us again.  I mean, that was one of the things I
           want to do next time was show you how we progressed.
                       In any way case, we're going to get to
           that in a little bit.  And unfortunately I didn't have
           it put in here, but try to look at the differences in
           example CVTR going from one to 4 nodes and then 6
           nodes.  Six nodes which are this way and 6 nodes which
           -- might be 2 this way and 4 this way and etcetera. 
           What you really find is you're not very sensitive to
           that.  What you're sensitive to is getting past one
           node so you can have air move throughout the
                       If you have various rooms, then it's
           certainly to your benefit to make those nodes, because
           things could potentially be more concentrated in that
           room if there's not sufficient natural circulation.
                       CHAIRMAN WALLIS:  You might say it's
           rather ridiculous if you take several rooms and mix up
           all the atmospheres and then saying that that's
           typical of everything that's going on.  That's s very
           crude and probably inappropriate way to look at what's
                       MEMBER KRESS:  So it would depend on where
           your break -- which room your break occurs in?
                       MR. HENRY:  Slightly. And as Tom said --
           Mike said, excuse me.  Your Tom, right?
                       CHAIRMAN WALLIS:  But the room where the
           break is very different from the rest of the
                       MR. HENRY:  I think Tom's point is we look
           at a break in each of the three different compartments
           for Beaver Valley, as an example.  And that's part of
           the analysis.  But it's not greatly different between
           them, but it is tenths of psi difference because you
           don't necessarily get the same condensing profile
           throughout the containment depending upon where the
           break is.  Because even though the compartments you
           might think are equivalent, but they don't necessarily
           have the same entry area and existing area, etcetera.
                       Anyway, to the point of nodalization, this
           is a demonstrative calculation.  This happens to be a
           Westinghouse two LOOP plant, and we divided this up
           into 5 nodes and also ran it with 1 node.  So one of
           the nodes is, of course, the reactor cavity.  The
           second node is the loop compartment which houses the
           two loops.  The third node is the annular region which
           is outside the loop compartment.  And then the
           operating deck, which is here, we put two nodes in. 
           one above the operating deck, one here and one in the
           region above the spring line.
                       CHAIRMAN WALLIS:  I have to ask why would
           you ever mix 1 and 5 in any kind of node?
                       MR. HENRY:  I think the answer to that is
           originally when people did design basis calculations
           that was judged to be conservative, give you a higher
           peak pressure.  And from a practical point of view it
           certainly makes sense that you would always have the
           same air pressure, pressure everywhere, so it limits
           the condensation rates.
                       CHAIRMAN WALLIS:  So the big action role
           of this is the condensation on structures and that
           sort of thing?
                       MR. HENRY:  Yes, the big actor is
           condensation on heat sinks.  That's what really drives
           the bus on whether or not you live within your current
           design basis pressure differential.  And some of that
           is shown in this slide.  What we have here is really
           single node and multi-node, which is shown here when
           it says 5 node and 1 node.  
                       So if I take these two, which says 5 node
           and 1 node, which is this solid line and this large
           dashed line here.  This is MAAP4, and I apologize I
           didn't get that written on there, but that does not
           have things related to atmospheric circulation to
           water entraining.  And as we walk through this you'll
           see some of those influences.  Whereas there here are
           MAAP5, which is the design basis code that we're
           looking for for these two sites.  And you'll notice
           that you can identify, this induced flow is equal to
           1 means the induced flow from the break was included
                       But as you look at this for 5 node with
           MAAP4, this solid line, and 5 node with MAAP5 you see
           no difference.  And it's true.  Because the only real
           thing that made a difference here was going from 1
           node to 5 node reduced the peak pressure
           substantially, roughly in atmosphere.  And the whole
           reason is that in the local near the break you pushed
           air away and you got enhanced condensation during this
           short time frame of about 10 seconds.  And that makes
           a difference.
                       And all we're doing here, it's the same
           code, it's the same physics.  Obviously, we're just
           changing the number of nodes.  So you can see even by
           including all these new models we're going to talk
           about from MAAP5 that didn't make any difference and
           it's strictly the single node going from 1 node to
           multi-node that made the difference.
                       CHAIRMAN WALLIS:  This is pressure
                       MR. HENRY:  Correct.  This is pressure
           absolute here.
                       CHAIRMAN WALLIS:  But it says G on the
           other side, right?
                       MR. HENRY:  And here, as you can see, this
           is one atmosphere there.  This is .5 and 1.5 times 10
           to the fifth.  This is absolute and SI units and we've
           put it in gauge over here.
                       For this particular plant, the design
           basis pressure is 60.  But, again, that's for -- 
                       CHAIRMAN WALLIS:  60 psig?
                       MR. HENRY:  60 psig.  And that's for
           design basis mass and energy increases, which are not
           in this calculation.  That was not the intent here. 
           The only intent was to illustrate the difference of
           going to multi-node.
                       And, as you might expect, for a large
           break LOCA this is just the temperatures in
           containment, again, in terms of Kelvin and Fahrenheit. 
           There's really not much difference between the two
                       CHAIRMAN WALLIS:  Of which node?
                       MR. HENRY:  Excuse me, Graham.
                       CHAIRMAN WALLIS:  Which node?  Temperature
           in the containment is different in different nodes.
                       MR. HENRY:  Well, of course, this only has
           one node.  This is the lower compartment, so this
           would be node number--
                       CHAIRMAN WALLIS:  It's different nodes.
                       MR. HENRY: Right.  This is 2.  I think
           that's 4 and 3.
                       But in essence it says that there's not a
           big difference between them, and that's not surprising
           for a large break LOCA, because the blowdown itself
           puts so much moisture into the atmosphere.
                       So then we take the same analysis, again,
           just from a demonstrative point of view what does it
           mean for main steam line breaks, and that's a little
           different story then.  But here we have these two are
           MAAP4, that have nothing after them.  And these that
           say induced flow=1, this is MAAP5, which again is the
           code that we're talking about here.
                       CHAIRMAN WALLIS:  I only see 3 curves.
                       MR. HENRY:  You always take my punchline,
           Graham.  This 1 node curve and this 1 node curve are
           on top of each other.  It doesn't make any difference
           from a practical standpoint.  And the reason this is
           different here is now, as we'll get to later on,
           what's influential in MAAP5 is induced circulation
           because a main steam line break goes on for a lot
           longer time.  But if you say there's only 1 node
           available, then as a result of that you're doing this
           momentum equation into one huge node of the
           containment, and really it's a huge mass and it hardly
           stirs it all all and issues related to enhancing any
           local velocities or entrainment really go away. So
           that part really disappears in one node and they
           become the same calculation.  
                       But when you go to 5 nodes now, of course,
           the blowdown is coming into one of those nodes, which
           is a much smaller region and also you, obviously, have
           higher heat transfer in that local.  Because it is 5
           nodes you're displacing air away from it and you have
           the potential for also reentraining moisture in the
           containment because a local velocity in that node can
           be above an entrainment criteria.
                       MEMBER KRESS:  Does that act like a water
                       MR. HENRY:  Exactly.
                       MEMBER KRESS:  Does the code then account
           for revaporization of the droplets?
                       MR. HENRY:  They can allow the droplets to
           revaporization.  But principally when you entrain
           something, you're entraining the film off the wall, so
           you entrain at the average temperature, which is T
           side on the outside and T wall.  So you actually get
           some subcooling.
                       MEMBER KRESS:  So you get some subcooling.
                       MR. HENRY:  Which really is the major
           thing to do.  But yes, Tom, it can revaporize.  In
           fact, that's part of what you see with multi-node
           because it can get down to something in the bottom of
           the containment for local partial pressure is not so
           high and the droplet might be warmer and it can
           vaporize down there as it falls through that node.
                       MEMBER KRESS:  Do you have a model for the
           rate of entrainment when the droplet --
                       MR. HENRY:  At the rate of entrainment and
           we put that into -- it goes directly into the aerosol
           model where the deposition rate is depending upon the
           airborne density.  So the airborne density --
                       MEMBER KRESS:  So you exercise -- is this
           still the aerosol model that was built by --
                       MR. HENRY:  Mike Epstein.  Yes.  So it
           becomes -- water is just part of the aerosol --
                       MEMBER KRESS:  Part of the aerosol?
                       MR. HENRY:  Right.  But the only reason I
           wanted to make a point, is the aerosol can come from
           either entrainment or from cooling of steam, both of
           them get put into the aerosol mix.
                       And this, Graham, to go back again, we
           have 4.  The piece in the legend, the two curves are
           simultaneous on top of each other because here again,
           the circulation has no influence.  It's so slow.  And
           what we get out of that since it's also not
           entraining, you get temperatures which are typical of
           what you see in some of the main steam line breaks.
                       CHAIRMAN WALLIS:  I don't know how we
           would apply it, the circulation model to those five
           different rooms and there's not going to be one big
           circulation pattern to these five rooms.  It just does
           not plot.
                       MR. HENRY:  I agree with that.  Just from
           the concept if I assume that it applies, it says it's
           not going to make any difference anyway because I'm
           too big, you can't make me circulate fast enough. But
           if it does and it entrains, you can see what's gained
           on the peak temperature, so it's again substantial. So
           not only is the pressure lower than the 1 node system,
           the temperature is also lower.
                       CHAIRMAN WALLIS:  These are all, of
           course, predictions?
                       MR. HENRY:  These are calculations, right. 
           We're going to get to comparing this with experiments.
                       I just hesitate saying predictions because
           it's really for a generitized system.  It's a two LOOP
           plant, but it's different from Point Beach's
           containment model in terms of nodes and level of
                       And also then we just look at for main
           steam line break between MAAP4 for a 5 node model and
           MAAP5 for 5 node model.  And this all becomes because
           MAAP4 knows nothing about atmospheric circulation,
           knows nothing about entrainment model.  And all we're
           comparing here is the influence temperature of those
           particular models which is what we'll talk about
           today.  And this has the multi-node in it, but it
           still isn't enough to really -- I'll get to CVTR.  If
           I take this approach from MAAP5, which we thought was
           a quite good code when we started that comparison, it
           overstates the pressure in CVTR by something in the
           range of 10 psi and it overstates the temperature by--
           I forget the actual number.  Like 50/60 degrees
           Fahrenheit.  This is the physics that we believe is
           controlling that.
                       So I mentioned MAAP is not a 1 mode model,
           so this isn't meant to -- this just shows you the
           various pieces of physics that are in the model, and
           some of these are severe accident related which Tom
           correctly asked us earlier what's being reviewed.  And
           what's being reviewed is that the containment model as
           it applies to design basis accidents.
                       Now, the key actors in that for these two
           different plants, we obviously focused on the heat
           transfer to heat sinks, which is shown here.  Tom, the
           aerosol model we just talked about, which is part of
                       The heat transfer to equipment, which is
           just all the steel and everything inside, whether it's
           handrails or ducting or whatever it may be.  
                       Condensation on all the walls and on all
           the heat sinks.  The metal, concrete, steel lined
           concrete, stainless steel line for fueling pools.
                       Fan coolers for Point Beach.  And, of
           course, the sprays for both Beaver Valley and Point
                       And lastly, the flow from the primary
           system.  This is not coming from MAAP now when we talk
           about design basis things. This is coming from
           Westinghouse design basis mass and energy release
           calculation for both large break LOCA and the main
           steam line break.
                       MEMBER KRESS:  This allows the use of
           sprays and fan coolers.  Is there a single criteria in
           the DBA that says you can't use the full capacity on
                       MR. HENRY:  Correct.
                       MEMBER KRESS:  That's probably --
                       MR. HENRY:  There's a whole run matrix
           that's used by both of the sites depending on what
           their specific conditions are.  They look at all the
           different kinds of single failures and look for the
           worst one in both sets of conditions.
                       And then also, some temperature is part of
           that, so that has another set of M&Es or way that you
           treat the previous M&Es, to mix or not mix them coming
           out of here.
                       And, again, we talked about uncertainties
           in the models, but there's also variations in the
           operating perimeters that have to be part of that DBA
           calculation.  You have to look for the most limiting
           case of operating conditions.
                       MEMBER KRESS:  I guess I would look for a
           net positive suction head located in those
           compartments that could prove affected.
                       MR. HENRY:  Well, the analyses that you
           look for is the net positive suction head when you go
           into recirc there for sure, yes.
                       MEMBER KRESS:  But you look at that?
                       MR. HENRY:  Yes, that's part of the --
                       MEMBER KRESS:  You don't --
                       MR. HENRY:  Yes.  And you look at it on a
           plant specific basis.  Because even when you have two
           units at the same site, they don't necessarily have
           the same systems.
                       Okay.  So this is the conceptual part then
           of the circulation, which is one of the key things
           that we think is missing in MAAP4 and it wouldn't buy
           you anything if you just looked at a one node anyway. 
           But the concept that it has is that a blowdown into
           this gaseous region adds momentum to the atmosphere. 
           Obviously, if we just had one node and we have
           momentum going in, where did it go?
                       CHAIRMAN WALLIS:  These are different
           nodes in the sense that there's previous nodes or are
           these different nodes within a given compartment?
                       MR. HENRY:  These are nodes in the same
           sense as the previous nodes.
                       CHAIRMAN WALLIS:  So there are rooms? 
           These are four different rooms?
                       MR. HENRY:  They may be rooms or they may
           -- this node boundary may be drawn in the atmosphere,
           as an example.
                       CHAIRMAN WALLIS:  I find this an
           extraordinary diagram.  I mean, the idea that there
           are rotating cylinders in each one of these rooms. 
           Fantastic.  And the idea that the incoming flow coming
           up like that rotates the cylinder on top of it is also
           fantastic.  And the idea that nothing happens between
           them except interfacial shear is also fantastic.
                       I couldn't understand what you could
           possibly be showing.  This is sort of a study of what
           it sees in liquid helium or something.
                       MEMBER KRESS:  You just conserve momentum.
                       CHAIRMAN WALLIS:  No, there's no momentum. 
           It's on the angular momentum.
                       MEMBER KRESS:  You've got momentum coming
           in to flow and you're going to put that all in the
           atmosphere until it circulates.
                       CHAIRMAN WALLIS:  It doesn't happen that
           way, it's all angular.
                       MR. HENRY:  Well the angular momentum is
           still momentum.  Graham, this is merely now to
           describe the concept.  Because the concept is it will
           -- let's first just think of a single node here as an
                       CHAIRMAN WALLIS:  But that's not the way
           it works.
                       MR. HENRY:  I know it isn't.  I know it
           isn't.  But from a single node point of view, it's
           easier to see what happened to the momentum that came
           in here.  Where did it all go?  Because in a single
           node you now have inflow, where did all that momentum
           go?  We can have conservation mass and conservation of
           energy, where did the momentum go?  It has to go in
           terms of somehow this fluid is circulating.
                       CHAIRMAN WALLIS:  I thought you were going
           to say, the incoming flow in region 2 there actually
           set up some sort of a circulation around the jet which
           helped the heat transfer to the wall?
                       MR. HENRY:  It certainly does that.  This
           doesn't mean that this sits here and spins with either
           a sphere or cylinder, whichever you choose on that
           one. It only means -- it only gets down to this
           fundamental thing right here.  Schematically what the
           code thinks of is I've got some velocity in this node
           which is different from the through flow velocity. I
           have circulation.  And this is merely a way of
           representing that, but that momentum that gets added
           to that node says the only way I can satisfy my
           momentum balance is I've got to circulate faster.
                       CHAIRMAN WALLIS:  I don't understand that.
                       MEMBER KRESS:  Well, it bothered me when
           you said that those nodes could be virtual nodes in
           the middle of the air and still do that.  Those are
           not really boundaries of rooms?
                       MR. HENRY:  Certainly whenever it is a
           boundary of a room, you use the boundary of the room. 
           But sooner or later you'll have to draw if you want to
           be able to investigate whether or not things can be
                       MEMBER KRESS:  I see.
                       MR. HENRY:  You have to eventually draw
           something up here, which is air.  Otherwise you're
           always just going to have rooms and this will always
           be one node and you won't have any stratification
                       MEMBER KRESS:  But you can't treat that in
           terms of momentum the same way --
                       MR. HENRY:  Let's talk about it.
                       CHAIRMAN WALLIS:  Let's go back to this
           other picture that you showed us.  I don't understand
           it.  You've got nodes and you've got flow between
           nodes, which is the usual thing.
                       MR. HENRY:  And that's part of the
                       CHAIRMAN WALLIS:  And within each node you
           have some sort of circulation as well?  Is that the
                       MR. HENRY:  Yes.  Because if you have flow
           coming in and you conserve mass and energy, so what
           you have going out of here is merely the through flow,
           then you won't be conserving momentum.
                       CHAIRMAN WALLIS:  Well, that's because it
           forces on the wall.
                       MR. HENRY:  No, even without that. You're
           just going to defuse or any momentum goes away. You
           don't satisfy it by the through flow alone.
                       CHAIRMAN WALLIS:  You're really confusing
           me altogether.
                       MR. HENRY:  Okay.  That's tough to do. 
           You're a hard guy to confuse.
                       CHAIRMAN WALLIS:  No. I mean the momentum
           balance works out always.  If you don't have -- if the
           momentum balance doesn't work out you've got forces of
           some sort.  The idea that the linear momentum is
           balanced by angular momentum is a very strange
           concept.  So something else is going on.
                       I think what you're saying is that the
           incoming flow in to that chamber stirs things up so
           the fact that this sort of -- some average velocity,
           which is low, is not characteristic of the real
           velocity seen by the wall.  Isn't that what you're
                       MR. HENRY:  Well, in a sense yes.  That's
           why I wanted to go back to just from a simple concept
           look at a single node. If I did an experiment with a
           single node.  And I blew down into that.  What would
           be the governing velocity of the through flow that
           comes out, if I make it one dimensional.  Of course
                       MEMBER SCHROCK:  The way you've run it, it
           doesn't look like there should be any shear between
           nodes in that picture.
                       MR. HENRY:  Well, we're going to get to
                       MEMBER SCHROCK:  You're both going in the
           same direction.
                       MR. HENRY:  Right. Yes, they're going in
           the same direction, but they don't necessarily have to
           be going at the velocity.
                       Suppose I put a bunch of structure up in
           this node, as an example, Virgil.  So this may be
           going at a much higher velocity than this.  I still
           have to represent the fact that there could be
           momentum transfer across this arbitrary boundary that
           the nodalization has created.  That's all it really
                       MEMBER SCHROCK:  How you come by those
           velocities, you're going to show us.
                       MR. HENRY:  Sure.  I knew you'd guys would
           have tons of questions on this, and that's why we're
                       CHAIRMAN WALLIS:  Well, I just understood,
           let's go to the next equation.
                       MR. HENRY:  Okay.  I would just say,
           before we leave this, Graham, you said it very well. 
           All this is meant to merely say -- all this says is
           that a node has a property that we looked at as
           circulation.  And that's merely the way of making sure
           that we do conserve momentum throughout these various
                       CHAIRMAN WALLIS:  Circulation cannot
           conserve momentum.  
                       MR. HENRY:  Okay.
                       CHAIRMAN WALLIS:  Circulation cannot
           conserve linear momentum.
                       MR. HENRY:  Yes, you're right.  It does
           not conserve linear momentum, but --
                       CHAIRMAN WALLIS:  Spin those things up to
           the speed of light, and it won't conserve --
                       MR. HENRY:  That's why I wanted to make
           sure we talked about the single node.  Within a single
           node is an example there can't be any linear momentum. 
           There's no out flow.  The only thing you could have is
           something that goes back to that's going to spin it
           somehow or other.  But you know from those kinds of
           experiments that you have a lot higher energy transfer
           at the wall, and that you get by the through flow
           velocity or the pressurization velocity.
                       CHAIRMAN WALLIS:  What is this -- can we
           go to the first line here?
                       MR. HENRY:  Sure.
                       CHAIRMAN WALLIS:  What's going on here?
                       MR. HENRY:  All this does is say that the
           way we look at this is the equation -- equating the
           impulse and the rate of change in that specific node. 
           What's it's mass and what it's velocity.
                       CHAIRMAN WALLIS:  "U" is a circulation
                       MR. HENRY:  Yes.
                       CHAIRMAN WALLIS:  So this is spinning?
                       MR. HENRY:  It's a concept of there's
           something going on and whether it's one thing or
           spinning this way or whatever, it's not a through flow
                       MEMBER KRESS:  It's not spinning.  It's
           just falling circle.  That's different than spinning.
                       MR. HENRY:  Okay.
                       MEMBER KRESS:  It's not angular momentum
                       CHAIRMAN WALLIS:  If you give something an
           impulse, it moves linearly, it doesn't --
                       MR. HENRY:  Yes, it does.
                       MEMBER KRESS:  Well, this is a linear
           motion.  But I don't know what "F" is yet, that's
           what's bothering me.
                       MR. HENRY:  We have three different forces
           that we look at, which is the force on the wall here,
           on the shear force on the adjacent node, which Virgil
           was asking about.  So if you have a difference in the
           rate at which you have the circulation velocity and
           nodes, then that has its own influence.  And then if
           you could have any kind of embedded structures that
           slow things down, they also have to be --
                       CHAIRMAN WALLIS:  What is Uc in your
                       MR. HENRY:  Uc is the property in the node
           which is --
                       MEMBER KRESS:  That's the result you're
           trying to calculate, right?  
                       CHAIRMAN WALLIS:  What is Uc in this
                       MR. HENRY:  Uc in the concept of the model
           is that in addition to through flow that this is also
           has --
                       CHAIRMAN WALLIS:  Where is the Uc?  I mean
           is it an average of some sort or is it on the wall, or
           in the middle.  Where is Uc?  I don't understand.
                       MR. HENRY:  Okay. Uc when we look at the
           energy transfer to this wall right here, Uc is the
           velocity that's dictating what the boundary line --
                       CHAIRMAN WALLIS:  Uc is the velocity along
           the wall?
                       MR. HENRY:  Uc is the free stream velocity
           next to the wall.
                       MEMBER KRESS:  It has to be some integral
           of the velocity in the whole mass --
                       MR. HENRY:  It is, yes, right, Tom.  And
           that's because it's coming from a momentum balance on
           each node.
                       When you have a through flow velocity and
           in each node you have a property called circulation. 
           And whatever that velocity is, that's what determines
           the free stream velocity next to the wall, it also
           determines the velocity that could entrain anything
           that's collected in that node.  Reentrain water, which
           is what --
                       CHAIRMAN WALLIS:  What you would call a
           turbulence velocity or be about the same thing?
                       MR. HENRY:  Yes.
                       CHAIRMAN WALLIS:  It would be about the
           same thing?
                       MR. HENRY:  Exactly the same thing.
                       CHAIRMAN WALLIS:  It is the amount of
           stirring up of the nodes, a measure of the stirring up
           of the fluid in the node by incoming flow?
                       MR. HENRY:  Exactly.  Exactly.  The only
           reason I pictured it this way is to try to break it
           down to the most simple thing.  The code thinks I have
           a velocity here and so where does that go.  Well, it's
           evaluating as if it is stirring or a turbulence
           velocity.  It's not the through flow velocity to the
           next node.
                       CHAIRMAN WALLIS:  Well, I think you're
           going to have to look at the details of this somehow,
           because, you know -- it may be a brilliant idea, but
           I'm having trouble understanding it especially treated
           like this.  There's no way that incoming flow going
           straight up there is going to stop, swirling things
           around in the way you've drawn that.
                       If you had said there was a level of
           turbulence, a mixing or something, I think I might
           come closer to understanding what you mean.
                       MR. HENRY:  But that's exactly what it is. 
           But the code has to have some concept that you're
           loyal to and how it incorporates this information into
           -- the information flow of what you're actually
                       MEMBER KRESS:  Did you mean for your Ms in
           that first equation -- second equation to be under the
                       MR. HENRY:  This is what the M is, this
           has the same units of force.  This is kilograms per
           second and --
                       CHAIRMAN WALLIS:  There's no way that in
           the way you've described Uc that that first equation
           you've got comes from a control volume analysis.  It
           comes from some kind of a word picture of some kind. 
           There's no way you can draw those Fs on a box and show
           me how the linear force produces angular momentum.
                       MR. HENRY:  Graham, I completely agree
           with that. You won't be able to take this into
           something and say, gee look that's now angular
           momentum.  But by the same token, when it -- when you
           hit all these structures, and I'm just trying to
           follow through what you've done, is you've created
           turbulence.  So some way this thing has a velocity
           that's different than the through flow velocity.
                       CHAIRMAN WALLIS:  I think that this is
           important and you're going to have to establish there
           some sort of a believable, mechanical basis for these
           Ucs in terms of physical phenomena.
                       MR. HENRY:  Absolutely.
                       CHAIRMAN WALLIS:  Because I'm not looking
           for something that's academic and terribly fancy --
                       MR. HENRY:  I know.
                       CHAIRMAN WALLIS:  But this seems to be
                       MR. HENRY:  We'll take that as an action
           item.  When you see us the next time we'll go through
           how we get to that.
                       CHAIRMAN WALLIS:  We have to sort of buy
           off on this.  It may turn out to be a brilliant move
           in terms of a way out of the box, so you're going to
           have to represent something which is important
                       MR. HENRY:  That's a very good way of
           putting it. You have to find something that's
           consistent with this big thing that represents 17
           nodes.  What's going on.  Right.  What's going on.
                       MEMBER KRESS:  And I think this is a
           reasonable concept if you have real boundaries.  But
           I'm not sure when you stick these virtual boundaries
           in -- 
                       MEMBER SCHROCK:  Yes, I'm having the same
                       MEMBER KRESS:  That's why I think I need
           to see this, the validation. 
                       CHAIRMAN WALLIS:  I'd like to see it also 
                       MEMBER KRESS:  I think it can be done,
                       MR. HENRY:  Well, we have some experiments
           here that focus on just that thing.
                       CHAIRMAN WALLIS:  I think what you're
           saying is if you open this door and you open that door
           and there's a draft going through here, it stirs up
           the fluid in the corners as well.  Is that the sort of
           thing you're saying?
                       MR. HENRY:  Yes.  And the rate at which it
           stirs it up is dependent upon the -- you can't get it
           from mass balance.
                       MEMBER SHACK:  But you're saying that the
           stirring is related to the momentum?  You don't get
           the stirring without some momentum.
                       MEMBER KRESS:  He actually has another
           equation that calculates this momentum going out. 
           He's got momentum coming in and going out.  It's the
           difference between those that goes into the stirring
           up.  It is sort of an integral -- it's an integral
           amount.  It has to go somewhere.
                       CHAIRMAN WALLIS:  Because you always get
           the forces on the wall.
                       MEMBER KRESS:  I'm ignoring those.
                       CHAIRMAN WALLIS:  You ought to give him a
           D for that.
                       MR. HENRY:  I knew we were going to have
           a lot of questions on this.  You guys are true to
           form.  You're still younger and quicker than I am.
                       Graham, what actually happens here if I
           take all of this out of here, is I would expect this
           to be a jet which begins to entrain as it goes up
           through here.  It entrains on the way up and it hits
           up here, and it spreads and it comes down.  But all
           that ends up being, stirring of this atmosphere, and
           stirring eventually -- well, basically it hits this
           wall and you take momentum out of it and you start
           turning it angular momentum now.
                       The way the code has a concept of that,
           because you can't -- it's very difficult to put all
           this kind of structural detail in --
                       CHAIRMAN WALLIS:  The code doesn't have
           any concept. You write the concepts.
                       MR. HENRY:  Okay.  You're right.  The way
           my code has a concept --
                       CHAIRMAN WALLIS:  No.  The way you imagine
           it does.  Let's get it clear:  This is some kind of a
           Henry fantasy.
                       MR. HENRY:  This goes way back.  We've had
           a lot of fun with this over the years.  So it's always
           been his fun, though.
                       Anyway, what is imagined for this then and
           the way it gets incorporated into the code is instead
           of trying to represent all this through detail, as an
           example, for jet flow etcetera, is to put this in
           something that says okay let's do the momentum balance
           on this and it will be interpreted as a velocity,
           which is turbulence, circulation and that velocity,
           that influence is what's used to determine the shear
           on the wall, the energy transfer to the wall and also
           it's ability to entrain.
                       So, that's why I put this up as a concept
           trying to put this into a large code that you could
           easily track through what it is or what its influence
           is and what are all the things related to slowing it
           down, whether the influence is out of entrained
           structures.  But you eventually have to get to drawing
           boundaries in the air someplace or you won't have
                       CHAIRMAN WALLIS:  It would be easier for
           me if instead of calling it circulation you said
           there's a schematic of -- there's a mixing, mixing
           velocities which are produced by the flows or
           something like that.  The idea of the circulation with
           these big cylinders rotating is something that I have
           trouble with.  But if you said -- same as you got flow
           in a pipe where the transfer to the wall it's governed
           by the turbulence which it's sort of set up by the
           main flow and you just don't say it's a linear flow
           because then you wouldn't have transfer to the wall at
           all.  Let us somehow model the turbulence.  I think
           that's what you're trying to do.
                       MR. HENRY:  That is what we're trying to
                       MEMBER KRESS:  But tell me, how do you get
           the momentum out?
                       MR. HENRY:  Well, see, I've got to get
           even with him next time.  We have a slide that's
           nothing but words and he's going to say can't you draw
           me a simple picture of this.
                       Okay, Tom.
                       MEMBER KRESS:  How do you get the momentum
           out there with a pressure difference in an area, a
           lost coefficient bobbing between the node?
                       MR. HENRY:  Yes.
                       MEMBER KRESS:  So really --
                       MR. HENRY:  Since it is a pressure
           different --
                       MEMBER KRESS: You don't have any screening
           in the momentum code.
                       MR. HENRY:  We have the pressure
           difference that says what is the flow rate that's
           leaving the node.
                       MEMBER KRESS:  Okay.
                       MR. HENRY:  And that's evaluated.  And
           what it carries with it is whatever that turbulence
           velocity is.
                       MEMBER KRESS:  It carries its node
           velocity with it?
                       MR. HENRY:  Yes.
                       MEMBER KRESS:  Computing the pressure
                       MR. HENRY:  The pressure difference --
                       MEMBER KRESS:  Is this that lost
                       MR. HENRY:  Yes.  Yes, there's a lost
           coefficient if it's just wide open, then there's
           basically no lost coefficient.  But, you know, the
           real fundamental thing at least we've discovered here,
           and that's what I want to also verify to myself as we
           work through this is what was the insight here was if
           you didn't this, then you never got the right answer.
           If you did have it, it didn't make much difference how
           much detail you went to as long as you said someplace
           that momentum got observed and therefore we had
           turbulence velocity which was higher than just the
           through flow velocity.
                       MEMBER LEITCH:  You've talked about this
           containment of pressure and temperature in macroscopic
           sense but then do you calculate pressure and
           temperature in each one of these virtual nodes, or
           which one --
                       MR. HENRY:  Each node has its own
                       MEMBER LEITCH:  And I guess my question
           then is that it seems to me to say in the LOCA, that's
           where the LOCA occurs, you would have a higher
           pressure and temperature.
                       MR. HENRY:  It does.
                       MEMBER LEITCH:  Does that become limiting?
                       MR. HENRY:  Generally not because it's
           usually the saturation temperature corresponding to
           the pressure in the room, and that's what we figure
           with most plant's design basis already is.  But
           certainly the pressure and the temperature in the
           break room are highest.  We'll get to a little bit of
           that later on.
                       MEMBER LEITCH:  Higher than the previous
           methodology that are indicated?
                       MR. HENRY:  Lower.  Lower pressure and
           some are lower temperature than previous
           methodologies.  Because you get more condensation by
           displacing the air.  Temperature is also mitigated
           because of all the moisture that gets entrained back
           into the atmosphere.  So it's hard to ever have super
           heat, which is again what the experiments seek.
                       MEMBER KRESS:  When you say dry runs is
           submerged pressure, what does this submerged mean
                       MR. HENRY:  It could be things like
           grading, I-beams.
                       MEMBER KRESS:  Submerged means it's just
           in there --
                       MR. HENRY:  This is submerged in the air
           right here, as an example.
                       MEMBER KRESS:  Okay.  It didn't mean it
           was under liquid?
                       MR. HENRY:  No.  No, it's just submerged
           in whatever the local fluid is.
                       MEMBER KRESS:  Submerged surfaces normally
           is a function of exposed surface area.
                       MR. HENRY:  Right.
                       MEMBER KRESS:  It depends on which
           direction the flow is going.  Does the code recognize
           flow direction somehow and --
                       MR. HENRY:  No.  No, it just thinks it's--
                       MEMBER KRESS:  It takes the polarity of
           whatever the structure is --
                       MR. HENRY:  If you have a pipe that runs
           through the room, you know, it doesn't care whether
           it's horizontal or vertical it has this turbulence
           velocity that's used.  We value how fast the it can
           slow itself down.
                       CHAIRMAN WALLIS:  How do you get drag on
           submerged structures?  It's the circulation velocity
           that's dragging on this structure or --
                       MR. HENRY:  Yes.
                       MEMBER KRESS:  Do you use some sort of
           friction lost coefficient or --
                       MR. HENRY:  Just drag coefficient.
                       MEMBER KRESS:  Do you have form losses in
                       MR. HENRY:  Well, it take it -- basically,
           again, it comes down to if you put it in the code,
           once you have it in it doesn't matter a whole lot on
           details. But what we really use are just drag
           coefficients associated whether we think it's a
           cylinder or a square, or -- it's usually a pipe or
           some kind of I-beam or grading --
                       MEMBER KRESS:  So there is some sort of
           consideration of flow direction versus the orientation
                       MR. HENRY:  Yes.  Again, yes.  I did not
           answer your first question right.  We're always
           assuming it's going across it, it's not going with. 
           You asked me a question, I responded incorrectly.
                       CHAIRMAN WALLIS:  I think you have
           something like a K epsilon here. You're saying that
           the turbulence level in these nodes is a source of
           energy to be fed in to increase the turbulence which
           is the flows and then there's various frictions and so
           on are dissipating turbulence.  So you get some
           measure then of atypical mixing velocity within the
           node.  I think that's the kind thing you're doing
                       MR. HENRY:  Yes.  As opposed to saying
           it's only the through flow velocity, which I'll come
           back to in a second.
                       One other aspect is the condensation
           occurs under natural convection conditions.  In MAAP
           we use the analogy for between heat to  mass transfer. 
           So the thermal boundary layer is the same as what we
           have for the natural circulation flow.  Of course,
           under laminar conditions, the Nussel number for all
           gaseous flow -- excuse me, for single phase flow is
           proportion to one-fourth power and then turbulent flow
           we have the lower Reliegh numbers, the one-third power
           at the higher Reliegh number, about .4 power which
           comes out of standard textbooks.
                       And what we use for that, there's the
           maximum of all these, depending upon what your
           specific conditions are.  The Reliegh number --
                       CHAIRMAN WALLIS:  Your whole idea of
           having circulation velocity is that the stirring
           enhances the forced convection and produces the
           transfer to the wall.
                       MR. HENRY:  Right.
                       CHAIRMAN WALLIS:  Now you're bringing in
           pre-convection --
                       MR. HENRY:  There are times where stirring
           velocity is so slow it has no real relevance.  It
           eventually dies away, in other words.  But there are
           times when this is the governing process of energy
           transfer to the wall.
                       CHAIRMAN WALLIS:  So you have mixed
           natural convection and stirring convection --
                       MR. HENRY:  You could also put here --
                       CHAIRMAN WALLIS:  Is this why you put the
           max in here, is that --
                       MR. HENRY:  Yes.  Because as the velocity
           dies away, then this natural convection will take
           over.  So you have to have a consistent way of
           addressing that as well.
                       CHAIRMAN WALLIS:  There could be a
           condition where the circulation would actually act in
           the opposite direction of the natural convection and--
                       MR. HENRY:  Right.
                       CHAIRMAN WALLIS:  -- the net result would
           be to reduce the heat transfer.
                       MR. HENRY:  Right.  That's one of these
           pieces right here.  When we use this, as I'll show you
           in a second, which is just a straightforward saying
           this looks nothing more -- it doesn't know that
           there's a film on the wall, you just have natural
           convection driven by the temperature difference and,
           therefore, what's the hydrodynamic boundary layer,
           what's the mass transfer boundary layer.  We find that
           we under predict the condensation rate when we go to
           specific experiments, separate effects experiments.
                       MEMBER KRESS:  What do you use for L?
                       MR. HENRY:  This is the height of the
                       MEMBER KRESS:  The height of the node if
           it's the virtual node.
                       MR. HENRY:  Yes.  It almost cancels itself
           out, as you know.
                       So what we have -- we'll get to, is it's
           strictly correlating factor that says okay what are
           our differences.  And when we look at the data, the
           higher the mole fraction of steam, the worse we do in
           this straightforward representation of going from
           single phase -- the heat transfer analogy, applying
           this single phase gaseous representation to the
           condensing potential.
                       MEMBER SCHROCK:  What do you do for
           condensation on your horizonal surfaces?
                       MR. HENRY:  The condensation on horizonal
           surfaces, it's usually dictated by the conduction on
           the surface.  That's water, it's very low, of course. 
           And if it's vertically -- if we're on a ceiling which
           is facing downward, then we end up using this same
           thing for experiments that I'll get to later. 
           Because, obviously, we have ceilings to the
           containment and --
                       MEMBER SCHROCK:  These natural convection
           for mass transfer formulations are not appropriate
                       MR. HENRY:  That's right.  And that's why
           we go to the experiments.  When we get to these
           ceiling, which are facing downward, that is the
           representation that they see in those particular
                       CHAIRMAN WALLIS:  I guess your document
           explains this Fm so I can understand it?
                       MR. HENRY:  This Fm is right here.  This
           is the correlating parameter, this is merely a
           viscosity radiogram that says --
                       CHAIRMAN WALLIS:  Oh, that's viscosity?
                       MR. HENRY:  This is a viscosity ration,
           this is to say this Nu of the gas over Nu of the
           fluid.  It merely gives us -- this is the most -- as
           we'll see in a second, this is the most effected
           parameter here that says the more steam you have, the
           worse this representation does.
                       CHAIRMAN WALLIS:  What is N?
                       MR. HENRY:  That is the mole fraction of
                       CHAIRMAN WALLIS:  So there's something in
           your documentation that justifies this equation
                       MR. HENRY:  This is strictly --
                       CHAIRMAN WALLIS:  So it explains where it
           came from in your documentation?  If we've got the
           code documentation, could we understand where that
           came from?
                       MR. HENRY:  I hope so.  This is really
           just a correlation for -- this is dimensionless
           obviously, and these which we -- the viscosity ratio
           because we have to cover all pressure levels here, the
           reason this is to the .8 is viscosity squared to the
           .4 power.  And this is linear because all this is is
           the fact that if you have low density gases that are
           being condensed, they can collect in the boundary
           layer and they can impose the natural convection which
           is going on.  And there's a ton of papers in
           literature that say this virtually cancels itself out,
           and it does.
                       MEMBER KRESS:  What happens to things that
           condense on the ceiling and other horizontal surfaces?
                       MR. HENRY:  Let me come back to that when
           we get to the experiments in a second, if you would. 
           Because we're going to certainly come back to that.
                       I just wanted you to understand when we
           get to natural convection, there is an enhancement to
           the condensation rate to the natural convection side
           that, again, comes from separate effects.
                       In the interest of time, I won't spend a
           lot of time on this because we already talked about
           it.  The mass energy releases comes from design basis
           calculations as they are applied to the containment
           models for both sites.
                       And I'm not going to spend a lot of time
           on this one either, because it really says much the
           same thing.  We look at all these types of accidents
           and as a result we'd like to find all the experiments
           that we could find that are applicable to these kind
           to test the total capabilities of the containment
                       The fact that the design bases mass energy
           releases come from separate models and they get their
           input to the containment model.  So in essence what
           MAAP is calculating for the core in the RCS is just
           thrown away.  It's ignored.
                       There's a mass energy release time
           dependent mass energy that's coming into the
           containment. That's exactly what we do to benchmark
           the calculation against these major experiments of
           CVTR and HDR.  We have the mass energy releases which
           are specified by the experimenters.
                       So I think I came to you guys once before
           and said would it be worthwhile to try to make sure
           that we preserve some of this very key data and put it
           in the codes and that's really what we're trying to do
           here as well.  So it's preservation activity as well
           as a convenient way to benchmark the code on a
           continual basis.
                       Experiments that we currently have pulled
           together, and this again, as I said, this is one of
           the key places that we want to have your feedback, is
           separate effects.  
                       We've used the Dehbi condensation
           experiments at MIT, the Anderson condensation
           experiments at Wisconsin, the Hitachi condensation
           experiments which related to a containment test but it
           gave us another separate set of tests that we could
           compare the condensation model against under natural
           convection.  Uchida condensation experiments, Tagami. 
           When we get to the spray experiments they just lightly
           touch on the nice thesis that was done in Canada by
           Kulic for both single droplet as well as spray header
           behavior.  And for countercurrent natural circulation
           we used the salt water, the brine water tests done by
           Epstein and Kenton for countercurrent natural
           circulation where you have both heavy over light as
           well as heavy over light with a through flow induced
           as well to assess that set of conditions that could
           flood the natural circulation flow too.
                       So these are the separate effects tests
           that we've built up to date.
                       The large scale integral tests include
           small break, large break and main steam line like
           conditions for HDR.  CVTR tests -- I should say the
           HDR tests are all international standard problems
           also. CVTR tests are steam into a containment.  Steam
           came from an adjacent power plant.  
                       And the containment standard problem tests
           were done at the Battelle Frankfurt facility.  There
           are two different types of hooking up of that
           particular set of containment compartments.
                       By doing these, of course, we're also
           demonstrating the use of external M&Es, because that's
           what these are.
                       MEMBER KRESS:  Have you checked into the
           Marveicken --
                       MR. HENRY:  We have, and they're so
           dominated by the suppression pool.
                       MEMBER KRESS:  They are, yes.
                       MR. HENRY:  But, indeed, those are ones
           that we like to add to this whole thing but not so
           much for these guys. 
                       That's a good point, Tom, because I wanted
           to -- there are a couple of other experiments here. 
           One in particular is a CSDF test at Hanford.  While
           it's ice condenser related, it certainly enables you
           to see what's this code going to do for the natural
           circulation flows that they put into those
           compartments.  So that's also part of it, but not
           listed here.
                       And the separate effects, one is the
           experiments that we used heavily were the experiments
           performed by Dehbi at MIT.  And this was interesting
           to us because you had a very long condensing length,
           even though this is maybe something like an inch to an
           inch and a half or so, but it had 3.5 meter condensing
           length that gave nice natural convection conditions to
           benchmark the model against.  And they also,
           obviously, had air as the noncondensible gas and they
           put in light gas to see what the influence was with
           helium also.
                       MEMBER KRESS:  The vials for the outer
           chamber heated or insulated --
                       MR. HENRY:  Yes.  These were insulated
           here so that the steam came from boiling water and the
           cold water was flowing through this copper condensing
           cylinder that they have here.
                       CHAIRMAN WALLIS:  And you put in a certain
           amount of air so you have some noncondensibles?
                       MR. HENRY:  Right.  And in some case they
           have a set of experiments where they bled steam
           through the boiling water as well.
                       CHAIRMAN WALLIS:  Now your code with nodes
           in it, now it really doesn't address the question of
           how do you predict the heat transfer coefficient in a
           geometry like this, does it?
                       MR. HENRY:  Well, natural convection heat
           transfer coefficient that I just showed you, you could
           either benchmark it based upon the condensing
           coefficient on the wall just due to the natural
           circulation condition --
                       CHAIRMAN WALLIS:  Are there correlations
           for a cylinder inside a cylinder or this kind of
           natural convection?
                       MR. HENRY:  Well, I can show you exactly
           what --
                       CHAIRMAN WALLIS:  You borrowed them from
           some other context, or something?  
                       MR. HENRY:  The size of the cylinder means
           that this almost looks like a flat plate in terms of
           what the -- vertical flat plate in terms of what the
           natural convection is on the outside.  
                       CHAIRMAN WALLIS:  But it's long, so you
           have flow --
                       MR. HENRY:  You do the hand calculation,
           this steaming rate is nowhere near what it takes to
           flood the film.  This steaming rate is very slow.
                       MEMBER SCHROCK:  Does it count as
           turbulent film?
                       MR. HENRY:  The following film?
                       MEMBER SCHROCK:  Yes.
                       MR. HENRY:  Yes.  The turbulent film gets
           fit for the turbulence.
                       CHAIRMAN WALLIS:  I didn't mean it that
           way in terms of that sort of flooding.  I mean you're
           going to use some sort of Nussel numbers or something
           or obtained from a correlation like the ones you've
           showed us?
                       MR. HENRY:  Yes.  It comes directly from
           those correlations.
                       CHAIRMAN WALLIS:  Assuming that this is
           the same as flat plate in an infinite environment?
                       MR. HENRY:  Yes.  That's the assumption.
                       And this is the data.  I apologize, these
           are pretty small figures, but this is at a pressure
           4.5 atmospheres. In essence, one atmosphere of air.  
                       This is at a pressure of 3 atmospheres and
           1.5 atmospheres.  For a variety of air mass fractions
           this is the way the data was reported by the
                       And then this plus the two on the next
           page have helium fractions, this being 1.7 and the
           others the 4 something and 8 something percent helium.
                       Now, this solid line right here is MAAP4,
           which is just those mass and energy, the analogy of
           heat to mass transfer applied to this set of steam
                       CHAIRMAN WALLIS:  So what you're testing
           is is this Fm?
                       MR. HENRY:  In essence Fm comes from
           these, Graham.  That's the correlation that comes from
           the separate effects tests.  What's the reason that
           this-- why don't these equations work, as an example. 
           Well, you can see, certainly, as we have more and more
           steam in here, the difference between those equation
           by themselves and the data increases.
                       CHAIRMAN WALLIS:  When you say comparison
           of MAAP with Dehbi's, the only thing that MAAP did was
           introduce this Fm.
                       MR. HENRY:  Right, and that's a
           correlation that comes from this information.
                       CHAIRMAN WALLIS:  The information itself
           came from these data.
                       MR. HENRY:  Right.
                       CHAIRMAN WALLIS:  It ought to fit them, it
           was itself derived from the data.
                       MR. HENRY:  My only point here is to show
           you this is all fit -- 
                       CHAIRMAN WALLIS:  How well it does?
                       MR. HENRY:  Yes, how well it does and the
           fact that you've known correlations from day one,
                       CHAIRMAN WALLIS:  Yes.
                       MR. HENRY:  This is a value of that Fm of
           1.  I'd like to get that as close to 1 as --
                       CHAIRMAN WALLIS:  And what this does is it
           justifies that Fm is a reasonable way of modeling
                       MR. HENRY:  Exactly.  Exactly. It's
           nothing to say this is how well this does.  But then
           I'm going to take this same thing to all the other
           experiments before I ever apply it --
                       CHAIRMAN WALLIS:  Okay, so now I begin to
           understand.  Because, you know, you send us our slides
           ahead of time, which was a very good idea.  
                       MR. HENRY:  Obviously.  Well, it's always
           a good idea.
                       CHAIRMAN WALLIS:  Well, I'll look at this
           and I say what has this got to do with containment. 
           It's really a separate effects to get the condensation
                       MR. HENRY:  Yes.  And I should if I look
           at this test, I should be able to go to other tests
           and do just as well.  If I don't do as well, I'd
           better broaden these uncertainties --
                       CHAIRMAN WALLIS:  So you're not modeling
           any of the circulations or --
                       MR. HENRY:  No, no, no.  In fact, this is
           really set up to be just natural convection is the
           dominant thing.
                       This is a value of 1.  This is a value of
           that Fm of .5 and 1.5.
                       Well, certainly from the standpoint of
           moving through various pressures, it does a reasonable
           job of bounding the data so we can find out the role
           of uncertainties or this uncertainty, where this
           particular thing applies in a containment analysis. 
           But before we do that, we obviously want to go to a
           bunch of other separate effects tests and see just how
           well does it do with those as well, different
                       This is the same calculation and the only
           difference here is that little term I say we put in,
           here's the influence of light gas accumulated in the
           boundary layer.  And the only difference between here
           and here is that term, and this a hydrogen -- or
           excuse me, a helium accumulation of 1.7 percent.
                       CHAIRMAN WALLIS:  This is the average heat
           transfer coefficient?
                       MR. HENRY:  Yes, it is.  That's all they
           measured in that test.
                       Now I should -- I mean, to give the author
           credit, he developed his own correlation for what that
           was.  This effective -- of course, this really should
           just be heat transfer coefficient here.  That's my
           fault.  But in essence, he had his own correlation. 
           Again, following in the structure of the code he
           wanted to put something and clearly understand how the
           code's using it.  That's why we put in our own
           correlation for it here, because we know exactly how
           the information is getting transferred from node to
           node to node.
                       But here you can see the obvious
           influence.  If you have a one node model, so we're
           always sitting at some kind of mass fraction down here
           someplace -- let's see, I should be more like in here. 
           Here.  As opposed to pushing air out so some nodes may
           be condensing here, but the break node is much more
           down here.  That has a tremendous influence on the
           peak pressure that you would calculate.
                       CHAIRMAN WALLIS:  So this noncondensible
           mass fraction appears as N in this Fm?
                       MR. HENRY:  NFST, that's all one thing.
                       CHAIRMAN WALLIS:  Your also influence as
                       MR. HENRY:  Well, NFST is the mole
           fraction of steam.  NF is mole fraction and ST is
                       CHAIRMAN WALLIS:  So this is saying that
           F is one plus something that's proportional to mole
                       MR. HENRY:  Yes.
                       CHAIRMAN WALLIS:  And the Nussel number
           goes up when N goes up or does it go down?
                       MR. HENRY:  The Nussel number goes up with
           increasing steam mole fraction.  The more steam we
           have in there, the more -- the measured -- yes, this
           is N for mole fraction and F and ST is steam.
                       CHAIRMAN WALLIS:  We're looking here at
           noncondensible mass fraction.
                       MR. HENRY:  Right.  Since it's only air
           and steam you could --
                       CHAIRMAN WALLIS:  Use it the other way
                       MR. HENRY:  Right.  But this is of steam
           here.  I could turn it around, but that's the way the
           experimenter reported his data and I always try to be
           faithful to what he represented as information.
                       MEMBER KRESS:  Well, how did he
           extrapolate against the cube of MC delta P of the
           water, probably, you've got the area.
                       MR. HENRY:  Measured wall temperature --
                       MEMBER KRESS:  Measured wall temperature?
                       MR. HENRY:  And the environment
                       I just want to make sure, this was no
           indictment of his correlation, but we put it in in our
           own way and we know how the code's going to use the
                       CHAIRMAN WALLIS:  Well, this looks a
           little strange, but I guess we've got to go on.
                       Usually when you put in a little bit of
           air it has a big effect, and this looks as if it
           doesn't.  As a matter of fact, it's rather a gentle
           effect of putting in air.  You have to put in a lot of
           mass fraction.
                       MR. HENRY:  Well, we're going to get to
           that, Graham.
                       CHAIRMAN WALLIS:  Because there's a zero,
           and you may never get to zero.
                       MR. HENRY:  Right, never get to zero
           there.  Right.
                       CHAIRMAN WALLIS:  Because zero is way off.
                       MR. HENRY:  Right.  We're going to get to
                       MEMBER KRESS:  I think that's the reason
           we didn't get it the first time.
                       CHAIRMAN WALLIS:  That's why I didn't
           understand it because Fm seems to be linear and steam
           fraction they always kind of leap up when you get very
           close to 1.
                       MR. HENRY:  Here's a couple -- Virgil
           asked me a question before about what happens with
           vertical -- with the flat systems, and in particular
           the ones that are important to us are the downward
           facing systems, which are the containment doom as well
           as all the floors of the compartments.  And that's why
           we focus on Anderson's experiments because he had,
           indeed, measured things, which I'll show you.
                       Let's go to his configuration, which were
           interesting to us so that we could relate what he
           measured in downward facing systems.  
                       So he ha something that looked like the
           top of the containment all the way down to the side. 
           So this was heat flux zone 1 up through 14.  That goes
           from vertically downward all the way up to -- excuse
           me.  Horizonal facing downward to vertical.  And it
           was a slice of the containment-like geometry.
                       MEMBER SCHROCK:  Is the water running down
           or is it dripping off?
                       MR. HENRY:  Both.
                       MEMBER SCHROCK:  Both.
                       MR. HENRY:  Both.  And the net result of
           what he saw as we go from 1 to 14 as shown here for a
           particular test, so this is horizonal facing downward. 
           This is cooling plate number one.  But here's number
           14, so this is the one that's vertical.
                       And what he saw from the practical point
           of view is that there's no difference in the energy
           transfer rate to the wall.  And he had two different
           ways of doing it with a heat flux measurement and a
           containment energy balance here.  And I need to get
           back into his thesis to make sure I understand what
           these -- the relative uncertainties of these are, but
           that will come.
                       And what we gleaned from this is for
           downward facing systems there's virtually no
           influence. And, as you know, of course, when you go to
           those natural convection kind of relationships, the
           length essentially cancels out of it anyway.
                       So, this is just a preview of how we're
           going to look at it, but at least this gave us -- and
           this is things that Anderson reported -- of various
           hot flow of temperatures and wall temperatures, this
           is what Anderson measured as the heat transfer
           coefficient.  And this is what Dehbi's correlation,
           which I mentioned here the author had formulated
           himself, shows.
                       As the temperatures increase, which means
           the pressure has to increase.  These are reasonably
           close.  If anything, Anderson's tend to be higher than
           Dehbi's or even more energy -- higher heat flux,
           higher heat transfer coefficient than what we're
           doing, except at this very low one.  So this will also
           dictate when we finally get to doing this detailed
           comparison what the uncertainty boundaries are that we
           think have to come from separate effects tests.
                       MEMBER SCHROCK:  So do we know where these
           experiments, where the relationship between the
           resistance in the diffusion layer is compared to the
           conduction resistance in the film?
                       MR. HENRY:  For most of these that relate
           to design basis type of energy transfer rates, there's
           hardly any resistance in the film.  Resistance is on
           the gas side and/or on the concrete wall, and the film
           is a very small amount of the resistance.  We
           struggled with that for a long time, Virgil, ourselves
           and we went to the trouble of making sure that we had
           this Laminar to turbulent film transition.  We saw no
           influence of it, but I'm not surprising you with it
           I'm sure, you've seen it many times.
                       MEMBER SCHROCK:  This funny shift from a
           lower value in Anderson to a higher value in Anderson
           as you go across these conditions which correspond to
           higher temperatures in the steam environment.
                       MR. HENRY:  Let me tell you where this
           comes from.  This comes out of Anderson's paper that
           he put into literature.  This table was in there --
                       MEMBER SCHROCK:  I haven't seen it.  Where
           was that published?
                       MR. HENRY:  I can get that to you. I'm
           trying to think.  I think it was in Nuclear
           Engineering and Design.  But I will get it for you.
                       MEMBER SCHROCK:  And this thing you showed
           us --
                       MR. HENRY:  I've got to get his thesis so
           I could understand where these numbers actually come
           from, because he's obviously averaged over some of
           these plates.
                       I'm sorry?
                       CHAIRMAN WALLIS:  On the previous
           transparency something went by me.  You've got plates
           at different orientations, is it related somehow to
           the picture in slide 24.  What were the various plates
                       MR. HENRY:  This is looking at a frontal
           view of his experiment.  This is the side view.  So
           these plates are individual plates that have their own
           cooling core so they can --
                       CHAIRMAN WALLIS:  This is like a sort of
           two dimensional containment?
                       MR. HENRY:  Yes.  Steam comes in here and
           they measure condensation rates in each one of these
           plates under average conditions that are in that
                       CHAIRMAN WALLIS:  And the orientation
           makes no difference?
                       MR. HENRY:  The orientation makes very
           little difference.
                       CHAIRMAN WALLIS: This might indicate that
           it's some sort of a circulation locally that's been
           happening rather than --
                       MR. HENRY:  It is spinning.
                       CHAIRMAN WALLIS:  Yes.  Is that what's
           happening or is it --
                       MR. HENRY:  I really think that -- and,
           again, I want to get his thesis so I understand more
           than what's in that particular paper. But there's a
           couple of things that have been going on here.
                       Obviously, you have heavy over light.  But
           if you collect enough water in this region, which is
           just horizonal facing downward, that by itself is
           going to fall away --
                       CHAIRMAN WALLIS:  And it drips off the
                       MR. HENRY:  Drips off and that certainly
           tears up any stable boundary layer.  And what you
           eventually get to over here, which is vertical, this
           is also in excellent agreement with Dehbi's vertical
                       CHAIRMAN WALLIS:  This is with a lot of
                       MR. HENRY: Right, this is.
                       CHAIRMAN WALLIS:  So it's nothing to do
           with Nussel's film, and the limiting thing is in the
           air spout.
                       MR. HENRY:  Right.  Right.  And to that
           effect, I should also mention they went to great
           trouble to make sure the condensing plates weren't
           limiting, for obvious reasons.
                       But I found this to be very helpful in
           going to these containment conditions.
                       CHAIRMAN WALLIS:  When this happens,
           there's some global replacement variable, which is the
           same for horizonal and vertical it's dominating
           everything.  Gravity doesn't really matter in that in
           that global picture.
                       MR. HENRY:  That's right.  It's probably
           a mixture of setting itself up this way as well as
           stuff coming down this way, and so gravity doesn't
           matter much.
                       But this also gives you the kind of
           information you need to say, the containment side,
           they're pretty complex geometry, how do I treat this
           thing.  And fundamentally what we say and our logic is
           the length already canceled out anyway, so from a
           practical point of view, systems which are facing
           downward we treat with the same kind of heat transfer
           coefficient, effective heat transfer coefficient,
           because that's what these are all put in.  HTC is heat
           transfer coefficient.
                       There are a couple of things we should get
           to, so I'm going to -- I do need to leave here not too
           long after 5:00, Mr. Chairman, if that's okay.
                       For the Hitachi experiments and for the
           Uchidas, I put -- this came, again, from the Hitachi
           paper that shows their measurement. And they had a
           geometry that was related strictly to suppression
           pool.  But again they were measuring the effective
           heat transfer coefficient.  Graham, the only reason I
           put this up here is, here's your steepness that you
           were looking for.  So that's all there.
                       And this is not my line, this is
           Hitachi's.  However, the way in which MAAP looks at
           Uchida, which is shown on that Hitachi slide is shown
           here.  So, that representation I showed you with Fm
           etcetera as a function, and now this is the ratio of
           noncondensible gas to steam.  Here's the steepness and
           this is the way that correlation looks.  And this
           needs to eventually have those same uncertainty
           boundaries put on it, but this was all we could do is
           digitize the information that came out in the original
           Geneva paper, which was a real tiny figure.
                       I'm going to skip the next ones because I
           want to get to some of the integral tests, because our
           whole process is to try to build the understanding
           from separate effects tests and then test their
           capabilities when we get to integral experiments.  So,
           if it's okay with you, I'm going to jump to the CVTR
                       So, this is CVTR, which is a
           decommissioned containment now. I'll wait until
           everybody gets this.  And they had a line from an
           adjacent power plant that came into here and it
           discharged into this node.
                       Now, a couple of things here.  This is a
           12 node model and as we talked before, this is a
           generalized containment scheme, so historically these
           nodes got added later down here.  That's why 11 and 12
           are down in here. And 9 and 10 are embedded nodes that
           are inside of the -- that we represent the refueling
           cavity and I forget what else inside.  It just doesn't
           show up on this figure.
                       CHAIRMAN WALLIS:  There are structures and
           things in there that you don't show?
                       MR. HENRY:  Right.  And that's part of the
           problem is, it's hard to find a description of all
           those structures.  But there is in the experimental
           report, there is a specification of what the heat
           sinks are and the uncertainties that they subscribe to
           their estimation of heat sinks.  So we use that.  And
           to some extent we have to do a little bit of guessing
           of where they are, but there's only a couple above the
           operating floor.  This particular thing had a steam
           generator on it. There's a fair size structure up
                       MEMBER SCHROCK:  When these guys do it for
           the plant specific, they have to make these choices?
                       MR. HENRY:  Right. They have to go look at
           where they have rooms.
                       MEMBER SCHROCK:  Yes.
                       MR. HENRY:  And they certainly have to
           have something which says I want to make sure that I
           can see stratification if it would ever occur.
                       MEMBER SCHROCK:  But you make a comment
           that it's hard to come by that information.
                       MR. HENRY:  For CVTRs it's hard to come by
           that information, because it's a decommissioned
                       MEMBER SCHROCK:  Okay.
                       MR. HENRY:  In fact, it's being torn down
                       The reason I wanted to make this point
           here, there is a generalized nodalization scheme.  You
           could hook nodes together anyway you want, so node 4
           can talk to node 11, there's no sequential problem
           associated with it.
                       The other thing I wanted to show you was
           the thermal couples that we will talk about here in
           comparison, there's a thermal couple 28 that sits out
           in this location, I think it's at elevation 370. 
           Thermal couple 11 is right below the operating deck,
           so it's in this region between these two nodes. 
           Thermal couple 7 is sitting at, and I think it's
           something like 297 or so, it's right here.  And
           thermal couple 5 is here.  And just so you know where
           they are inside the nodalization scheme.
                       And one of the things I need to show the
           staff and of course this committee in the future is
           suppose we started with one node, what would we get? 
           If we had two nodes, what would do we get? If we have
           four, what do we get?  
                       And also, I can tell you ahead of time,
           basically if I would have made this one node, two
           nodes, three nodes, four nodes, I'd get something very
           close to what you see now.  But don't take my word for
           it.  I owe that to you in the future.
                       We used these 12 nodes because we wanted
           to see what are all the axial temperatures and the
           influences on containment pressurization.  So, we'll
           keep coming back and forth to this, I'm sure.
                       There were three tests; test number 3,
           number 4, number 5. The only difference is test 3 had
           no sprays at all in it, so steam went into containment
           and then it just cooled down over a number of hours.
                       In test number 4 they turned the sprays on
           at about 210 seconds at half the capacity that the
           containment had.  
                       And test number 5, exactly the same except
           full capacity of the sprays.
                       So this is the pressure that's measured
           for all these different gauges throughout the volume. 
           And, of course, they're in very close agreement, which
           is expected.  And this is only the first 400 seconds,
           this is the same set of measurements over the first
                       Remember that thermal couple 28 that's up
           somewhere around 370 or so, that's this thermal couple
           TC28 and showing here both the temperatures in node 1
           and node 2, and this is that measurement for zero to
           400 seconds and zero to 4000 seconds.
                       The sprays come on just about right here. 
           You see a little kink right there, and that's when it
           comes on.  And so all this that you see here is all
           being driven by the spray cooling.
                       MEMBER KRESS:  The break is when the steam
           quit going in?
                       MR. HENRY:  Yes, that's exactly right,
           Tom, the steam -- the mass energy stopped right here.
                       Now, why we do this to begin with.  We
           thought MAAP4 was a pretty good code, as it
           generalized nodalization and it had the kind of energy
           with the natural convection thing I showed you that
           didn't have Fm in it, and it allowed air to be pushed
           around containment.  And we did the best job we could
           with MAAP4 and this CVTR test, we had a pressure that
           was up here.  It over-predicted the pressure by about
           7 psi, as I recall.
                       The best nodalization we could think of,
           all the heat sinks, everything else, the best thing
           that we could put in there.  So that's what really got
           our attention.  What are we missing?  And the thing
           that we're missing is when we do mass and energy
           balances, as an example, we don't end up having any
           idea of what that turbulence, whatever that
           circulation is because we never were solving for it. 
           That momentum just disappeared.  So everything that
           was driving through the containment was all just due
           to through flow and what it had to have to pressurize
           the various other nodes to the same pressures.  And it
           would push air either way.  But no way could we get it
           down from up here to there.  So that's where the whole
           concept got started:  What does this mean?  What are
           we missing in these nodes?
                       The other aspect is the temperature.  We
           over-predicted this temperature by something like 50
           or 60 degree Fahrenheit.  So we obviously had some
           things that were really missing in both.  What governs
           the peak pressure, what determines the temperature in
           these nodes.
                       And we also looked at the rest of the
           temperatures as we worked down into the containment.
           So this one is TC11 you see here, which is right below
           the operating deck by 4 or 5 feet.  TC7, which is
           further down.  And you can see with this one having a
           peak of something in the range of 230, it's not too
           much different than right above the operating deck.
                       When you get further down, this is hardly
           increasing at all.  And that's still a challenge to us
           because this particular rise that you see right here
           is only because the system's pressurizing because the
           pressure is going up.  
                       So what we do in order so that we have
           some kind of perspective of what's going on, these
           three lines right here are a heat sink that's a
           quarter inch -- assumed to be quarter inch thermal
           couple, which is a big thermal couple, just sitting in
           that node.  So how much would we slow down this
           measurement if we had this generic thermal couple
           sitting in there, because we don't know what that
           thermal couple or RTD looks like, that wasn't in the
                       Now you can see, that slows it down a
           little bit, but still not as much as -- there's
           something else even going on that makes that lower
           region even cooler.  But if we didn't have this
           turbulence circulation velocity, we would really
           overstate this temperature again, and this would also
           be overstated because the pressure's higher.  This
           whole thing is coming about because the pressure is
           going up and it's just eV to the gamma as a constant.
                       You can see certainly after the sprays
           come on, we get quite bit agreement down low in the
           containment as well.
                       And then we go to the very bottom of the
                       This is TC5 for the first 400 seconds, the
           first 4000 seconds.  And now we get much better, at
           least understanding that this could be because of some
           thermal response to the thermal couple and maybe it's
           seeing some water dripping down from the wall.
                       This is again the average temperature up
           in node 2, but the key thing I wanted to mention to
           you the CVTR provides is it has detailed
           representations of the liner temperature in the break
                       So this is the side of the liner that
           faces the gas space.  This is the side of the liner
           that faces the concrete.  And in CVTR the liner does
           not contact the concrete, at least not at the
           beginning of the test.  It's separated by 3/8th of an
           inch.  It doesn't mean that it couldn't be pushed out
           during the test.  
                       But this is our evaluation of the liner
           temperature that's facing the steam.  And the reason
           this data that's shown here and the data shown here is
           exactly the same, and the whole reason is that we
           don't know where that measure was taken.  We just know
           where its elevation is.  We don't know azimuthally
           where it was in the test report.  This is that
           particular heat sink, which is our break node, which
           was node number 2.  And this is the node right beside
           it at the same elevation.  So we show a little bit
           higher temperature, of course, in that node than we do
           here, but at least we can see it's certainly following
           the liner temperature quite well, which is one of the
           evaluations that these guys have to do.  They have to
           evaluate the liner temperature during these design
           basis calculation.
                       So that's why this was particularly
           important to us.  And this one I'm going to put in
           better context for you in the future, but this is,
           again, the liner temperature.  We have nodes in the
           concrete, which can be fairly thick.  This is our
           node, and this is what their temperature is, imbedded
           in the concrete.  And, again, these two are exactly
           the same thing.  It's just that they're two different
           nodes at the same elevation.
                       I will put this in a heat flux context for
           you, so you can really see this in terms of how much
           energy, what's the transient deposition of energy into
           the concrete, because that's really matters.
                       CHAIRMAN WALLIS:  I don't quite understand
           the lines here.  The data are the results.
                       MR. HENRY:  Right.
                       CHAIRMAN WALLIS:  And there's something
           called MAAP calculations -- which line is that?  There
           are two solid lines --
                       MR. HENRY:  This is best estimate or what
           I should be calling realistic just to get --
                       CHAIRMAN WALLIS:  Realistic and
                       MR. HENRY:  Okay.
                       CHAIRMAN WALLIS:  And then the data is way
           down below there.
                       MR. HENRY:  Right.  This calculation right
           here is basically the same as what's up here, because
           this is the inside liner temperature.  There's the
           liner, then there's a gap and there's the concrete.
                       CHAIRMAN WALLIS:  And your thermal couple
           reading is way down there?
                       MR. HENRY:  No, this thermal couple is
           sitting in the concrete.
                       CHAIRMAN WALLIS:  And what's the other --
                       MR. HENRY:  This is our first concrete
           node.  The node can be -- so that's why I say in the
           future I'll put this into the heat flux rate.
                       CHAIRMAN WALLIS:  Somewhere in between.
                       MR. HENRY: Right.  I'll characterize the
           transient heat flux, which is more meaningful for you. 
           I apologize for that.
                       But this, of course, is easier to
           represent.  Okay.  They have temperatures in the
           concrete, how well you're doing there.
                       So these CVTR tests are very important to
           us because that was the first clue we had there's
           something that's really missing in this process and
           what is it.  Unfortunately right after that are the
           spinning cylinders.
                       There's a couple more here that I'll go
           through very quickly, again, Graham, with your
           permission, just because this is a particular
           containment configuration that gets put together two
           different ways for these two CASP experiments.
                       CHAIRMAN WALLIS:  It's very easy.  We do
           this for homework.  I mean, you could just take one of
           the rooms with flow in one and up the other side and
           do some of that room calculation, you would show that
           these flows in and out set up separation cells in the
           room; they wouldn't be quite like your cell, but they
           would be straight up.  
                       MR. HENRY:  That's right.
                       CHAIRMAN WALLIS:  And you could actually
           predict from some of CFD calculation what the role of
           heat transfer should be.  That would be not too
           difficult a thing to do.
                       MR. HENRY:  You got my attention.  I'm
           sure we'll come see you again.
                       CHAIRMAN WALLIS:  Students do this for
                       MR. HENRY:  I guess we'll have to find
           someone who's younger and quicker.
                       CHAIRMAN WALLIS:  Well, the frequency here
           has CFD capability.  It could do the same thing.
                       MR. HENRY:  Sure.
                       CHAIRMAN WALLIS:  That might be the more
           realistic thing you should put in the cylinder.
                       MEMBER KRESS:  Well, the building in some
           ways you have to validate the concept he is trying to
           put across.  
                       MR. HENRY:  And we'll go look for some
                       I also apologize, I skipped over the first
           HDR experiment very quickly, which is a large break
           LOCA to get to CVTR, which is more meaningful.  The
           reason I skipped over HDR, not that it doesn't mean a
           lot, it does.  But as I showed you earlier on with 1
           and 5 nodes, there was no benefit to looking at
           circulation or turbulence or anything else.  MAAP4 did
           a good job with HDR.  But the CVTR it stunk, so we
           wanted to get right to the heart of the issue.  And
           the reason was we believe we were not correctly
           representing the potential for energy transfer of the
           break nodes.
                       I should also mention the way we do this
           calculation of turbulence, etcetera, we get about the
           right kind of circulation velocity that was observed
           in CVTR, which is a very difficult thing to measure. 
           They did have some -- I think they had turbine driven,
           turbine flow meters sitting in the annulus.  You get
           down to the bottom of the containment, their velocity
           is almost none existent.  So it's only a couple of
           nodes that see this enhanced energy transfer rate.
                       Okay.  The reason I want to touch briefly
           on these, D15 with CFP1 with this schematic -- which
           was again, now, Graham, this is their schematic, not
                       CHAIRMAN WALLIS:  I realize that.  The
           actual thing looks quite different.
                       MR. HENRY:  Right.  This looks like it's
           a straight through thing, which is what its intent
           was, but when you get to the real thing -- I guess we
           already went past it.
                       CHAIRMAN WALLIS:  Did they clear the
           special building for this test?  
                       MR. HENRY:  Well, this is a whole series
           of tests.  This went on for a number of years.
                       CHAIRMAN WALLIS:  -- a series of
                       MR. HENRY:  So this says, for those of you
           that may not have seen this before, it's breaking your
           node out of room 6, and then it goes through room 4 to
           room 8, then up to room 7 and into and out of 4. 
           These two roles are in line, and then into room 5 and
           into room 9.  So it looks all straightforward there. 
           But just so you appreciate the complexity of it, when
           you look at the configuration, room 9 which is shown
           here, includes all this annular region here, which is
           there also, as well as this big hole in the middle
           right here, which is this hole right there.
                       So here's room 6 and this is the break
           pipe coming into it.  And room 6 then flows through
           room 4 here, the level of path, and this is room 4,
           that little tiny thing, but it is the full height. 
           And goes into room 8.  At room 8 goes up into room 7,
           which is right above it.  And room 7 over to room 5. 
           Here's 8 to 7.  And back through 4 into room 5 and
           then up to 9.
                       So it's a very complicated structure, but
           it at least gives you an idea -- gives you a test of
           how well you're doing representing the pressure
           distribution in this particular test.
                       I also wanted to mention to you that there
           are the two experiments; the test configuration of
           course comes from the test report.  The mass energy
           releases and their uncertainties are characterized in
           the individual test reports.  So we used this.
                       The additional information is, and this
           got us in touch with Teja Kantzleiter who was the key
           experimenter on this a long time ago.  He was kind
           enough to send an email that defined the inner
           surfaces of the outer concrete walls, the thing that
           defined room 9, to have a 1 millimeter surface
           coating, that the inner walls had half a millimeter
           surface coating on both sides.  So all those floors
           and ceilings, and that had a thermal conductivity of
           about .3 watts per meter degree K.  And that the
           concrete itself, of course, is density to specific
           heat, and thermal conductivity to the best they could
           figure out was about 2 watts per meter degree Kelvin.
                       So the information that you have in front
           of you -- and again to try and get the most
           information to you, these are fairly small figures --
           but this represents the transient pressurization for
           the most realistic behavior in containment.  And where
           this says optimistic and pessimistic, the pessimistic
           also has in it their maximum mass and energy release. 
           The maximum you can get from that uncertain analysis. 
           And the optimistic has the minimum here, whereas this
           which is realistic is using what they thought was
           their best estimate of how fast this came in the
           containment. And, of course, these are measured with
           -- it's a two-phase flow and they're estimating it
           from a momentum measured on the drag disk.
                       So this is the pressure in containment. 
           Temperatures for the three different things, again, in
           these rooms close to the break.  And this one is the
           break room.  
                       And this looks like a real mess here, like
           a bunch of spaghetti, but what's shown, again, is this
           generic thermal couple.  So if we look at the solid
           line, which is right here, as an example, that's the
           most realistic representation, and this is that
           generic thermal couple that we respond, and then right
           above it here. 
                       So, again, I don't know what their thermal
           couples look like.  I don't know if they're close to
           any structure, etcetera, but at least we can see that
           something is -- it's roughly a quarter of an inch
           piece of structure holding the thermal couple in place
           -- is one of the reasons these things could lag and
           then the temperature could stay up.  Because out in
           here there is basically no motion going on.  It's just
           radiation, the environment, and natural circulation. 
           The blowdown's all over with back in here.  Obviously
           the blowdown is over with right there.
                       And this because we had -- we had talked
           before about measuring the pressure differences
           throughout the containment, these are now compartment-
           to-compartment pressure differences.  So now from room
           4 to room 7 this is the measured pressure difference. 
           Again, this is in terms of Pascals, of course, but
           it's negative because of just the direction of the
           flow.  But this is from room 7 to room 8.
                       CHAIRMAN WALLIS:  Well, the Pascal is
           pretty small.
                       MR. HENRY:  Right, these are fairly small
           pressure differences.
                       This is 10 to the 4th here that we're
           looking at --
                       CHAIRMAN WALLIS:  Oh, there is a 10 to the
                       MR. HENRY:  Right.  That's still not a big
           pressure difference.
                       And the other point I wanted to make to
           you, this one that was measured to be zero because
           there are things we still want to make sure that the
           code comprehends but does not comprehend -- as I said
           it's a work in progress -- this is room 4 to room 5. 
           And that's that small little room where the holes are
           in line.  So in essence we get streaming flow directly
           from 5 through 4 into 7.
                       CHAIRMAN WALLIS:  And you don't deal with
           streaming flow very well?
                       MR. HENRY:  Right now the way the code
           thinks of it, it goes from room 4 to 5 -- whichever
           way this is -- and mixes and then it goes out.  So it
           needs a delta P to get out, that's why this is here. 
           But in essence it says there's no reason for me to
           stop here.
                       MEMBER SCHROCK:  Momentum never began and
           got quieted down.
                       MR. HENRY:  Right, and that is linear
                       The only reason I wanted to show you that,
           is there's another test, again, schematically now,
           it's the same set of rooms but they're hooked together
           differently.  So now the break is into that little
           room 4.  Then it goes up and goes out those two holes,
           which in 4 it was streaming through this way.  Now it
           goes out both ways into room 7, then into 8, into 5,
           up into 9 and eventually comes around into room 6.
                       So this shows you, it's the same set of
           figures now, but it's going into this little room here
           4, so here's the pipe that's going into it, right
           there.  So it's this little square, but it is the full
           height and this is a hatch on top which after the
           experiment was over we detected there was a leak path
           here from this break room into 9.  So, again, we
           include that in the representation.  But as it goes
           into that room, then it goes out sideways right here
           into room 7 and 5, whichever way it was.  One of them
           went down into, I think, 8.  Yes.  And 5 went upwards
           into 9 here and eventually came around and filled 6
           from down below.
                       CHAIRMAN WALLIS:  So if you have one of
           these horseshoe shaped rooms, or whatever, I don't
           know how you describe it.
                       MR. HENRY:  Yes.  Half a ring.
                       CHAIRMAN WALLIS:  Half a ring around it,
           you have the same circulation velocity in all parts of
           it in your model?
                       MR. HENRY:  Yes, there's the same
           turbulence velocity in each node.
                       CHAIRMAN WALLIS:  It's a first
           approximation, right?
                       MR. HENRY: Right.  And the key thing here
           is --
                       CHAIRMAN WALLIS:  I think a realistic
           model would actually say we'll model the annular ring
           as one thing and the cap as another.  Two nodes
           instead of one.  Even though it's one room, but it's
           so different.
                       MR. HENRY:  Yes.
                       CHAIRMAN WALLIS:  You're not going to do
                       MR. HENRY:  Yes, I can.  I can.  
                       And since you've made that point, I should
           also tell you that clearly it represents this part of
           this room 9, there's 2 nodes out here, 2 more nodes up
           here --
                       CHAIRMAN WALLIS:  There's all various
           nodes that --
                       MR. HENRY:  In the calculation, yes.  But
           I thought your point was in these also, because these
           -- here's where the half thing is.  You could
           certainly do that.
                       One reason I thought this was also helpful
           is the first was the linear progression through the
           nodes.  This is more like parallel flow paths.  
                       And this is, again, the best estimate and
           most realistic for pressurization in the break room 4,
           and this is over the first 50 seconds, this is over
           the first 1000 seconds.  It didn't come through very
           well, but that's 10 to the third here.  
                       And then this is pressure difference from
           room 4 to room 9 and the first 2.5 seconds.  And the
           pressure history of room 9 over the first 50 seconds,
           which is one of the nodes in the outside region.
                       This is -- 7 to 8 there's an example,
           which is break room into the next largest room out. 
           Excuse me.  7 is the next largest room out and then 8
           is the room it goes down into.
                       CHAIRMAN WALLIS:  When you've got this
           concrete -- this insulating concrete wall -- doesn't
           the thermal resistance of the insulation actually end
           up dominating rather than the condensation side?
                       MR. HENRY:  The only thing it's insulating
           is the paint. The paint matters --
                       CHAIRMAN WALLIS:  I thought they said they
           had some coating on this.  
                       MR. HENRY:  Well, that's the coating, so
           it's like an epoxy coating.  And that epoxy coating is
           only on the walls which are going outside, and it's
           there to be a sealant.
                       CHAIRMAN WALLIS:  But it is a significant
           heat transfer, isn't it?  
                       MR. HENRY:  Yes, it is.  And it is prior
           to calculation.
                       We don't have to go through this detail to
           compare.  We just want to make that you can see that
           it's doing a reasonable job on compartment-to-
           compartment pressure history, transient pressurization
           as well.
                       When we look at all these things, whatever
           those various things that are happening in a point of
           time, whether it's natural convection, forced
           convection, etcetera, the uncertainty boundaries you
           have for each of those models that came from separate
           effects tests were the same in all cases.  So you're
           not tooting one of those parameters for a specific
           test, and different tests.
                       The part which gets into uncertainties
           gets to a short set of propriety slides, so I don't
           know if we need to -- we can be out of here probably
           about 15 minutes.
                       CHAIRMAN WALLIS:  Well, you said this was
           work in progress, so we're not -- you don't have to
           give an evaluation of the MAAP in its final form.
                       MR. HENRY:  No.
                       CHAIRMAN WALLIS:  This is just to let us
           know that you're doing it and get the feedback.
                       MR. HENRY:  Get the feedback; I certainly
           got plenty of that, and I appreciate it.  And if
           there's any experiments that you think that we should
           have in this mix that we have overlooked --
                       CHAIRMAN WALLIS:  When will this come up
           in its final form?
                       MR. HENRY:  We have a deadline to submit
           to the staff in January, which is next year.
                       CHAIRMAN WALLIS:  Fairly soon?
                       MR. HENRY:  Fairly soon, yes.  And then
           the staff has heard from us twice on this; once in
           June and yesterday to keep them updated on our
           approach by the experiments.  We want to make sure
           that when it comes to the technical basis that we're
           looking at things that you guys think, that they're
           the driving force -- here's how I understand it -- it
           must be doing, what the containment must be doing.
                       CHAIRMAN WALLIS:  So you expect to come to
           us again fairly soon with a finished product?
                       MEMBER KRESS:  The staff review.
                       CHAIRMAN WALLIS:  Or the staff has to
           decide you want to do that.
                       MR. HENRY:  Right.
                       CHAIRMAN WALLIS:  They may not want you to
           see us at all.
                       MR. HENRY:  That's between you guys and
           the staff.  Certainly if you want us to come talk
           about it, we're at your disposal to talk about it.
                       CHAIRMAN WALLIS:  Well, it looks like a
           considerable step forward in the modeling of
           containment.  Up there on the right-hand page
           dovetails with industry.  
                       MR. HENRY:  Appreciate that.
                       MEMBER KRESS:  Of course, the staff, they
           plan, I guess, I don't know, access, too.
                       CHAIRMAN WALLIS:  And I think also, since
           this seems to be key for you, maybe that can be used
           for these outbreaks.
                       MR. HENRY:  Yes, we're particularly keen
           on making sure that once we have a model that goes
           with the experiments, that all that knowledge that's
           associated with the experiments gets transferred into
           their --
                       CHAIRMAN WALLIS:  I think the outbreaks
           are going to come to ACRS anyway.
                       MR. HENRY:  Right.
                       MEMBER KRESS:  Do you view this as saying
           that in old code and this is a way to utilize that
           margin by getting rid of some of those conservatisms?
                       MR. HENRY:  That's exactly right, Tom. 
           But one of the ways that we would say that is that the
           top suppliers do the right things for the right
                       CHAIRMAN WALLIS:  This margin isn't the
           real margin, it's a margin of something in theoretical
           equations, because you didn't know what was going on,
           you had to have a -- when you know more you don't need
           such a big margin.  You probably mustn't get the
           impression that they're somehow producing a safety
           margin by producing an uncertainty which enables us to
           make a better decision.
                       MEMBER KRESS:  It's a some kind of level
           of safety.  I think you are reducing the margin,
           because we're going to uprate the power and we're
           going to put more stuff in, we are reducing the
           margin.  This just tells you you've got enough margin
           there that you can do that.
                       CHAIRMAN WALLIS:  I don't suppose you can
           tell us what you mean by margin?  
                       MEMBER KRESS:  The difference between the
           pressure and the design limit.  The actual pressure
           you get for design limit.
                       CHAIRMAN WALLIS:  Actual pressure, not
           just pressure.
                       So do you move on to the staff, then, or
           do you want to say a little bit about this?
                       MR. HENRY:  Instead of passing out the
           proprietary slides, let me just say what's really in,
           because that how we treat the uncertainties, what we
           will eventually bring back to you.  And what's
           inherent in the process is that we believe that the
           way you get closure is that you test against -- you
           develop your uncertainties with separate effects
           tests, and you work to these large scale tests for
           closure.  And by closure we're looking for the
           realistic and the pessimistic and optimistic and we
           try to stay away from conservative, because sometimes
           we don't know what that is, given the attribute that
           you're investigating.  And we look to see if we can
           bracket the data, not bound the data.
                       And once we're able to bracket the data,
           we feel we have a 100 percent and 10 percent kind of
           understanding of what's driving the bus and all these
           analyses and also in the experiments.  That's really
           what's in the proprietary part of how we establish
           that closure.
                       CHAIRMAN WALLIS:  Is this congruent with
           the CSAU?
                       MR. HENRY:  Well, unfortunately I was part
           of that once upon a time.  It is consistent with that,
           but -- and I was part of it when it was for direct
           containment heating.  And the only thing that's
           different here from that is I tried to simplify it in
           my own mind to fewer steps.  But I also established
           closure back to, say, you think you got this model,
           are you able to bracket the data with the model, given
           that uncertainties that comes from something else to
           allow you to understand the detailed physics with the
           processes that you're working or you just globally
           bound it?  And we would prefer to be able to bracket
           it.  These guys take it in-house, we want them to have
           something that the engineers know where it all came
                       CHAIRMAN WALLIS:  You talk about the 95
           percentile dosage, or just bracket?
                       MR. HENRY:  We prefer to deal with just
           bracket, but you certainly could take this to a
           distribution.  If you can do it with just bracketing,
           well again the uncertainty bounds for individual
           physics come from things like we saw with separate
           effects tests.  If you could live with that, you
           shouldn't have to do anymore.  If you want to look at
           a distribution, you got to go back to those and define
           the distribution and you put it into a Monte Carlo
           kind of approach at a plant.
                       CHAIRMAN WALLIS:  Do you have separate
           effects tests of these circulation velocities?
                       MR. HENRY:  You know I'm going to go look
           for them.  For the CFD calculations of flow into a
           closed node, right?
                       MEMBER KRESS:  This CVTR --
                       MR. HENRY:  If I knew, I could find that
           book called two phased flow, but I don't remember
           those being in there.
                       MEMBER KRESS:  Your CVTR containment
           model, are there virtual boundaries in it as well as
                       MR. HENRY:  Yes. I'm sorry, Tom. I meant
           to make that point when we were there.
                       MEMBER KRESS:  Yes.  I thought that was
           the one test where you really had --
                       MR. HENRY:  I appreciate that.  I'm going
           to show you a couple.  When we get to the HDR there is
           a virtual boundary, but there's so many nodes, so many
           rooms in the containment that you need to represent
           all these -- or least virtually at least half of
           these.  And there's a boundary up here because at 
           E11.2 there was stratification.
                       When we get to CVTR, which I'm glad you
           made that point, because those virtual boundaries are
           here, here, here, here and this is treated as a
           virtual boundary because I can't find out what the
           grating was as you walk down.  They're not very
           specific about it and all the pictures are above the
           operating deck.  But this definitely is.  These are
           boundaries here and that is.
                       These are not -- obviously as you can see,
           these aren't annular rings, these are just slices
           through the containment.  So, this is half of a
           cylinder and this is half of a cylinder here.
                       MEMBER KRESS:  How does MAAP deal with
           creating stratification when you got light gas and a
           heavy gas.
                       MR. HENRY:  You can accumulate gas in the
           node just because it eventually gets transferred up
           and you slow down the condensation and slow down,
           therefore, the energy transfer rate.  Or you could
           have it come in as it does in HDR at this kind of
           location and it has a plume model that evaluates its
           ability to mix if all this is really just relatively
           quiescent system.  Mix and rise to the top, but if
           it's not completely mixed by the time it gets to the
           top, it accumulates.  And those virtual boundaries,
           and even when we get to the plume model, that
           entrainment rate goes back to the Recue Spalding
           entrainment model, and then the kind of entrainment
           coefficient that we use is defined by their model is
           0.1, which is basically what they say to look at real
           tiny gas-to-gas.  But if you go look at volcanoes it's
           roughly 0.1.  It's the best estimate of the
           entrainment rate of surrounding material.
                       Now we have bounding values on the other
           side of it that are pessimistic and optimistic,
           whichever the influence of the specific attribute that
           you're looking at.
                       CHAIRMAN WALLIS:  At 0.1 it's like you're
           mixing when you get a plume that produces --
                       MR. HENRY:  That's exactly what it is.
           That's where it all came from.  If we got something
           that's an extremely powerful jet what's it doing.
                       MEMBER KRESS:  In these containments, both
           of them have sprays?
                       MR. HENRY:  Yes.
                       MEMBER KRESS:  If those are working all of
           this gets overwhelmed by the sprays.  The sprays do
           everything.  So this is only if the sprays are assumed
           not to work?
                       MR. HENRY:  No, the sprays don't always do
           everything.  But they eventually get into plant
           specific analysis.  But main steam line breaks, the
           sprays do part of it but it's still pressurizing.  The
           only thing that turns around eventually is the M&E
                       MEMBER KRESS:  What is the time for the
                       MR. HENRY:  The typical time for sprays is
           anywhere from 45 seconds to a minute.  But for main
           steam line breaks, the M&E may last for 100, 200
                       MEMBER KRESS:  -- the time that you get
           into the recirculating mode. 
                       MR. HENRY:  Well, we're still in the
           injection mode, but it's still the sprays are not
           necessarily turning the pressure around, they're just
           slowing down its rate of pressurization.  But the
           spray momentum is also part of this whole thing here.
                       CHAIRMAN WALLIS:  I understand some folks
           have to go to the airport.
                       MR. HENRY:  I appreciate that, Mr.
                       CHAIRMAN WALLIS:  I don't want you to go
           to the airport with too much momentum.
                       MR. HENRY:  I'm going to spin out of here. 
           I apologize, but we do have to leave because I do want
           to -- I will touch base with Rich, but the people from
           the sites will be here also.
                       CHAIRMAN WALLIS:  The people from the
           sites are going to be here?  I thought they were going
           to leave first.
                       MR. HENRY:  Excuse me.  Tom Beach has to
                       Thank you for all your consideration.
                       CHAIRMAN WALLIS:  That was very
           interesting presentation and interaction.
                       MR. HENRY:  I enjoyed it.
                       MR. LOBEL:  My name is Richard Lobel, I'm
           with the Plant Systems Branch in NRR I didn't come
           prepared to make a presentation because the submittal
           hasn't been made.  There was question about how we
           were going to proceed with the review, and we had a
           short preliminary meeting this morning to talk about
                       The review will be done in conjunction
           with Research.  In fact the Office of Research will do
           most of the review because they, we felt, had the
           expertise and the others and also had the resources to
           do this. We wanted to make sure that we could do a
           very thorough complete review of this, and the
           expertise that's available in Research helps us do
                       We will do contained calculations. We will
           ask probably both licensees for the input to their
           specific calculation in one form or another, whatever
           is convenient for them and for us to use.  When we do
           an audit, that's usually how we work things out.  We
           have a conference call and ask them to submit it in
           whatever form is convenient for the people here who
           are going to be doing the calculations.
                       We also will be doing a little more of the
           study of the uncertainties in the containment
           experimental data.  A lot of work has already been
           done by Research, and that was another reason for
           getting the Office of Research involved in what
           normally would be just an NRR review.  Because they
           have a lot of expertise from work they've done in the
           development of the contained code and comparing with
           experimental data.  And since Bob Henry didn't go into
           it very much because a lot of that was the proprietary
           part, but his method depends a lot on the use of
           experimental data in the calculation of procedure
           itself.  And so we wanted to look in more detail at
           the experimental uncertainty, too.
                       We haven't thought about it in a whole lot
           more detail than that yet.  We plan to do an
           aggressive review when we get the submittal.
                       The plant specific submittals aren't due
           until May.  We're going to try to get the plant
           specific information before the submittals are made if
           that's possible so that we can start doing the
           calculations earlier and identify the significant
           issues as soon as we can.
                       That's about it.
                       MEMBER LEITCH:  Have you used the MAAP5
           before?  In other words, are we looking at -- there's
           two things we talked about was basically the change
           from MAAP4 to MAAP5 and also the nodal concept.  Has
           the change from 4 to 5 been reviewed previously?
                       MR. LOBEL:  No, I don't think we even have
           MAAP5 in-house yet.  They will be submitting that at
           the same time.  I understand from talking to Bob Henry
           just before this session started that they will be
           giving us a copy of that at the same time they make
           the submittal.
                       MEMBER LEITCH:  I see.
                       CHAIRMAN WALLIS:  When you say a copy, do
           you mean a copy of the -- the modern copy of the code
           or you mean the documentation?
                       MR. LOBEL:  No, the documentation. 
                       CHAIRMAN WALLIS:  Do you actually a
           running copy of the code in electronic form?
                       MR. LOBEL:  We may, and we may use that,
           but we'll probably -- the plan is now to concentrate
           more on using contained and comparing with their
           analysis and let them run --
                       CHAIRMAN WALLIS:   with other codes the
           policy has been to endeavor to get an electronic copy
           of the source code so you can run it.
                       MR. LOBEL:  Well, we may do that and, you
           know, we're certainly interested in your
           recommendations and suggestions.
                       CHAIRMAN WALLIS:  Well, we definitely
           thought it was a good idea.
                       MEMBER KRESS:  Well, this may be an
           exception.  MAAP I think belongs to EPRI and it's not
           the licensee's code.  It's not their privy to even
           give it to the staff I don't think --
                       MR. LOBEL:  But on the other hand, if we
           really wanted that and considered that part of the
           review, the licensees would have to try to accommodate
           that as part of the review.
                       Let me say, a lot of this isn't going to
           be a detailed review of MAAP.  What we're going to try
           to do more is review the method, because MAAP is a lot
           more than just the containment.  And what we were
           going to try to do is -- the thinking is in NRR that
           there's a couple of different options for the review
           of MAAP that's still being talked about, as I
           understand, in the office.  And what we would do is
           what we've been calling option one, which is look at
           the models that are pertinent to the containment and
           see that they're reasonable but concentrate mostly on
           doing an independent analysis and a review of the
           methods that are used in this procedure, which is a
           lot more than just the code.  It's their use of
           uncertainty and experimental results.  You saw that a
           little of that from the pictures he was showing.
                       So, it's not going -- the plan was not
           going to have this be much of a review of MAAP itself
           except the specific containment models that are
           involved and to concentrate mostly on audit
           calculations and correlations, and that.
                       MEMBER KRESS:  I presume this is a changed
           licensing basis.  Does that open the door for all
           other PWRs to come in and do the same thing?
                       MR. LOBEL:  It could, it depends on the
           results of the review.  What we've been asked to do
           now is just to do the review of a general report and
           then two plant specific analyses.  But there was talk
           at the June meeting about maybe having them come in
           with a topic report that applied to more than just the
           two plants.  There wasn't any talk of that yesterday,
           so I don't know what they're planning to do for that.
                       The broader the review is now, the easier
           it will be on us in the future.  We won't have to keep
           going through this for four loop plants and ice
           condensers and what else it may apply to.
                       CHAIRMAN WALLIS:  Have you reviewed their
           momentum equation formulation?
                       MR. LOBEL:  No.
                       CHAIRMAN WALLIS:  You've heard the
           discussion here?
                       MR. LOBEL:  Yes.
                       CHAIRMAN WALLIS:  It would be unfortunate
           if we had a code which seemed to work in comparison
           with data but which had somewhat bizarre
           interpretations of momentum balances.
                       MR. BOEHNERT:  Extraordinary.
                       CHAIRMAN WALLIS:  Yes.  I'm sure Bob Henry
           is smart enough to fix that up, but what appeared here
           looked very strange.  Maybe we're just being stupid. 
           It just looked very strange.  We don't want to get
           into a situation where something seems to work but the
           theoretical basis justification doesn't really stand
                       MR. LOBEL:  Well, I think that we all can
           agree that the phenomena is there certainly --
                       CHAIRMAN WALLIS:  For other reasons than
           the way that the math is actually sort of encoded in
           the momentum equation. Maybe that the phenomena going
           on which caused it are well represented by the way
           things come together.  And then maybe then it's up to
           the person to bring together the documentation to give
           a technically believable justification then for what
           they do.
                       MR. LOBEL:  The philosophy we've used in
           other reviews is to try to not get in a position that
           you were just talking about where the code may be
           predicting data but have something in it that isn't
           physically real.
                       CHAIRMAN WALLIS:  That's the last thing
           ACRS wants to have to fight regarding the --
                       MR. LOBEL:  I guess we've already answered
           this a little bit, I thought it would be worthwhile
           for them to come and give you a presentation because
           this is so new.  It's a completely different approach
           than what's in the standard review plan now for the
           most part.  We didn't have any plans to ask them to
           come back again, but it sounds like to hear from them
           after a point where we've gotten into the review
           ourselves, so maybe a presentation on what they've
           done and what we think of it after a round of
                       CHAIRMAN WALLIS:  Then you've got the
           submittal.  They're going to have much more detail
           about the technical basis because, again, what we've
           seen so far doesn't really explain it well enough.
                       MR. LOBEL:  Yes.  I'll share that with you
           if you want to see the submittal when it comes in.
                       CHAIRMAN WALLIS:  Does the committee have
           some other points at this time?
                       So what we need is just to -- the full
           committee meeting we need an oral presentation --
                       MR. BOEHNERT:  We make a subcommittee
           report, or you're scheduled to make a report.
                       CHAIRMAN WALLIS:  -- progress and that we
           have some questions.
                       MR. BOEHNERT:  Yes.
                       CHAIRMAN WALLIS:  And I don't think we
           need much time with the full committee.
                       MR. BOEHNERT:  I think we've got a half
           hour scheduled. 
                       CHAIRMAN WALLIS:   All right.  We're going
           to make it on time unless Professor Schrock has a lot
           of questions.
                       MEMBER SCHROCK:  No, I'm going to my taxi.
                       MEMBER KRESS:  Now we know how to fix it
           so Virgil doesn't have any comments.
                       CHAIRMAN WALLIS:  Any reason why I should
           not recess -- okay.  I close the meeting, is that
                       MR. BOEHNERT:  That's fine.
                       (Whereupon, at 5:27 p.m. the meeting was


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