Materials and Metallurgy - September 26, 2001


                Official Transcript of Proceedings


Title:                         Advisory Committee on Reactor Safeguards
                               Materials and Metallurgy Subcommittee
                               Steam Generator Action Plan

Docket Number:  (not applicable)

Location:                 Rockville, Maryland

Date:                     Wednesday, September 26, 2001

Work Order No.: NRC-032                               Pages 1-166

                   NEAL R. GROSS AND CO., INC.
                 Court Reporters and Transcribers
                  1323 Rhode Island Avenue, N.W.
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                          UNITED STATES OF AMERICA
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                       STEAM GENERATOR ACTION PLAN 
                                 + + + + +
                            SEPTEMBER 26, 2001
                                 + + + + +
                            ROCKVILLE, MARYLAND
                                 + + + + + 
                       The ACRS Materials and Metallurgy 
           Subcommittee met at the Nuclear Regulatory Commission,
           Two White Flint North, Room T2B3, 11545 Rockville 
           Pike, at 8:31 a.m., Dr. F. Peter Ford, Chairman,
                 DR. F. PETER FORD, Chairman
                 DR. MARIO V. BONACA, Member
                 DR. THOMAS S. KRESS, Member
                 DR. DANA POWERS, Member
                 DR. WILLIAM J. SHACK, Member
                 DR. JOHN D. SIEBER, Member
                 NOEL F. DUDLEY, 
                 ACRS Cognizant Staff Engineer
                           AGENDA ITEM                     PAGE
           Opening Remarks by the Chairman. . . . . . . . . . 4
           Introductory Remarks by Mr. Sullivan . . . . . . . 6
           Presentation by M. Banerjee on Status of . . . . . 8
                 Steam Generator Action Plan
           Presentation by Steve Long on. . . . . . . . . . .23
                 Status of Action Plan DPO Issues 
           Presentation by Ted Sullivan on NEI 97-06. . . . .26
           Presentation by Kenneth Karwoski on. . . . . . . .70
           Overview of South Texas Steam Generator             
                 Tube Integrity Issues
           Presentation by Joseph Muscara on SG . . . . . . 105
                 Action Plan                                   
           Presentation by Charles Tinkler on . . . . . . . 135
           Overview of Severe Accidents
           Presentation by Stephen Bajorek on . . . . . . . 145
                 Thermal Hydraulics
           Presentation by Christopher Boyd on. . . . . . . 153
                 CFD Predictions
                                                    (8:31 a.m.)
                       CHAIRMAN FORD:  The meeting will now come
           to order.  This is a meeting of the ACRS Subcommittee
           on Materials and Metallurgy.  I am Peter Ford,
           Chairman of the Subcommittee.
                       ACRS Members in attendance are William
           Shack, Mario Bonaca, Thomas Kress, John Sieber, and
           Dana Powers, and hopefully Steve Rosen.
                       The purpose of this meeting is to discuss
           the status of the staff's Steam Generator Action Plan
           and South Texas, Unit 2, steam generator tube leakage,
           and to decide what further ACRS reviews should be
                       The Subcommittee will gather information,
           analyze relevant issues and facts, and formulate the
           proposed positions and actions, as appropriate, for
           deliberation to the full Committee.  Noel Dudley is
           the Cognizant ACRS staff engineer at 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 on September 11th, 2001.
                       A transcript of the meeting is being kept,
           and 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 members
           of the public regarding today's meeting.
                       The staff issued the Steam Generator
           Action Plan on November 16, 2000.  The Action plan
           consolidated half a dozen or more staff regulatory
           activities related to steam generator tube integrity.
                       The staff updated the Action Plan on May
           11th, 2001, to include items associated with the
           differing professional opinion associated with steam
           generator tube integrity.  
                       After hearing the staff's presentation, we
           will develop recommendations on what activities we
           want to review and comment on, and when we should
           schedule those reviews.  
                       We will now proceed with the meeting, and
           I call upon Maitri Banjeree, of the Division of
           Engineering, Office of Nuclear Reactor Regulation, to
                       DR. SHACK:  Before we start, Mr. 
           Chairman, I should mention that I have a conflict of
           interest here because Oregon is doing work on steam
           generators for the NRC.
                       CHAIRMAN FORD:  A;ll right.  
                       DR. POWERS:  Is that why they keep falling
           apart all the time?
                       CHAIRMAN FORD:  Oh, I'm sorry. 
                       MR. SULLIVAN:  My name is Ted Sullivan,
           and Maitri is the next speaker.  I will just take a
           minute and spent a little bit on the introduction to
           give you a little bit more information on what we are
           going to be doing this morning.
                       Maitri is our first speaker, and she is
           going to be giving an introduction to the steam
           generator action plan, and basically tell you what
           some of the early activities were that led to the
           development of the action plan, and what it considers,
           and what it doesn't consider.
                       One of the major elements in that action
           plan is NEI 97-06, which is our steam generator
           regulatory framework initiative that we have been
           working on for quite some time.
                       So I am going to get up after Maitri and
           give a presentation on the status of that, and the
           issues that we are currently dealing with that are
           holding us up from completing that initiative.  
                       After the break, Joe Muscara is going to
           give a presentation on the DPO related issues in the
           action plan.  His focus is not going to be going
           through the entire set of issues in that portion of
           the plan.
                       Rather, he is going to focus more on the
           near term activities.  We thought that would be of
           more benefit.  And then after that, Ken Karwoski is
           going to do two things.  Basically, he is going to
           discuss two of the action plan items related to the
           DPO that are NRR responsibilities, as opposed to
                       And then he is going to transition into a
           discussion of what has been going on in the past
           couple of intervals related to the South Texas use of
           voltage based repair criteria.
                       And I agree with what you had to say in
           terms of the objective.  I think that we are not going
           to get into a tremendous amount of detail, as we are
           covering a lot of material here.  So I think it would
           be good to decide what additional briefings you would
                       And certainly in the area of NEI 97-06, we
           are prepared to get into more detail if you are
           interested in a subsequent briefing.  
                       DR. POWERS:  And in what phase of the
           briefing will we discuss the iodine spiking issue?
                       MR. SULLIVAN:  It should be covered in the
           DPO portion, but Joe, can you address that?
                       MR. MUSCARA:  I will have one view graph
           on the status of the operation.
                       DR. POWERS:  Okay.  An in-depth
           discussion, I can tell.  This is an easy issue to
           solve, Joe.  
                       MR. MUSCARA:  That's what they tell me.
                       CHAIRMAN FORD:  Thank you, Ted.
                       MR. KARWOSKI:  The first question is are
           you related to Sanjo Banerjee?
                       MS. BANERJEE:  Not that I know of.  
                       MR. KARWOSKI:  Okay.  Then you are okay
                       MS. BANERJEE:  That's reassuring.  My name
           is Maitri Banerjee, and I am the NRR lead project
           manager for the steam generator action plan, and I
           will provide you a short background and overall status
           of information on the action plan.  Can everybody see
           this slide?
                       All right.  Here is a historic overview of
           the --
                       DR. POWERS:  History begins with an IP2?
                       MS. BANERJEE:  And of significant actions
           taken, and that led to the issuance of the steam
           generator action plan, and this kind of explains
                       The purpose of the plan.  As Chairman Ford
           pointed out the plan was originally issued in November
           of 2000, and it was issued keeping the NRC performance
           goals in mind, and in maintaining safety in the IP2
           area, and renewing public confidence, and also using
           NRC and stakeholder's resources effectively and
                       And the purpose of the plan is to direct,
           monitor, and track NRC's activities to completion so
           that we get to an integrated steam generator
           regulatory framework.  
                       DR. POWERS:  Can I ask what an integrated
           regulatory framework means?
                       MS. BANERJEE:  Well, I am going to defer
           answering that question to Ted Sullivan, who is going
           to talk about NEI 97-06 activities that are going on.
                       DR. POWERS:  Well, maybe you can give me
           an idea of what we are integrating with what.  
                       MR. SULLIVAN:  My name is Ted Sullivan,
           and I think what we are trying to do is to make sure
           that all of the various elements involved in ensuring
           tube integrity are integrated into a steam generator
           regulatory framework that considers more than just,
           say, inspection and repair issues.
                       But that goes beyond that into all the
           other disciplines that are involved in ensuring tube
           integrity.  Disciplines related to doing risk
           assessment, and the research that is developed that
           feeds into that, and that sort of thing.  I think that
           is the general idea, and the radiological issues.
                       MS. BANERJEE:  Do you have any other
           questions?  If not, the action plan consolidates a
           number of activities, including Indian Point 2 Lessons
           Learned Task Group Report, and the OIG report that was
           issued subsequent to that, and then it was revised in
           May to incorporate the steam generator DPO related
                       And obviously the milestones related to
           the staff review of NEI 97-06 is in there, and we will
           make revisions in the future to incorporate milestones
           for resolution of GSI 163.  
                       We also anticipate revisions to
           incorporate GSI 188 and Draft Guide 1073.
                       CHAIRMAN FORD:  Could I just for clarify? 
           The resolution of the steam generator DPO, that is
           essentially the output from the ad hoc committee,
           subcommittee from ACRS?
                       MS. BANERJEE:  Yes, that's correct, from
           the NUREG requisition.  The steam generator action
           plan also includes some non-steam generator related
           issues that came out of the OIG report.  They had
           issues in the EP area, and also that task group's
                       And the second bullet is sort of a
           disclaimer.  It says that the action plan doesn't
           address any plan-specific reviews or industry  efforts
           related to voltage-based tube repair criteria.
                       CHAIRMAN FORD:  Is there a reason for that
           disclaimer?  Why the disclaimer?
                       MS. BANERJEE:  I guess these are plan-
           specific issues that are not addressed in the action
           plan.  The action plan is basically what came out of
           the Indian Point 2 lessons learned task group, and
           what came out of the OIG report subsequent to Indian
           Point 2, and also the DPO related issues.
                       And so we didn't go into addressing
           Generic Letter 95-05, any kind of industry work being
           done in that area, or any kind of plant-specific
           licensing work related to voltage-based tube repair
                       CHAIRMAN FORD:  But surely as you go
           through the action plan, which is your calculations,
           experiments, and studies, there has got to be a
           feedback into what the plant is actually doing.
                       MS. BANERJEE:  Ultimately, yes.
                       CHAIRMAN FORD:  And so when does that
           occur?  That second bullet is saying, hey, we stopped
           short of actually calibrating our calculations against
           what is in fact happening.  Isn't that a over
           simplification of what that statement is saying?
                       MR. SULLIVAN:  I think what we were trying
           to say is that there is a lot of plant-specific
           reviews that are going on.  They continually go on.
                       They might have to do with ultimate repair
           criteria that we maybe reviewing, and what we are
           basically saying is that they are tracked in other
           systems, and so we weren't going to track them in the
           action plan.  
                       And then related to the second half of
           that, they are a number of issues that industry has
           been asking us to take on, their proposed
           modifications to GL 95-05, and that in a sense would
           be relaxations.
                       And the staff's view was that the priority
           effort should be on the action plan when resources are
           available, and we will get back to taking those kinds
           of reviews on.  So for the second half of that, it was
           really more of a priority of resources matter.
                       MS. BANERJEE:  Thank you, Ted.  This slide
           presents an overall status of the action plans. 
           Currently, we have 40 major items, milestones, in the
           action plan, 11 of which consist or came out of DPO.
                       And 20 of the 40 major milestones are
           completed, and there is one milestone with a schedule
           to be determined.  This has to do with how we
           communicate risk to the public.  
                       The agency has done some work in the area
           of communication plan and currently NRR is looking at
           ways to improve that.  And that is the overall status.
                       This slide lists some of the significant
           activities in the action plan.  A regulatory summary
           was issued in November of 2000, with experience from
           Indian Point 2 and ANL, and a number of issues were
           raised by both task groups, and the OIG related to
           steam generator inspections, GSI inspections.
                       And in response to that the base line
           inspection procedure was revised.  It focuses on the
           steam generator ISI inspector, in terms of how the
           licensee is going condition monitoring, and how they
           are meeting the performance criteria, versus looking
           at any current testing.  
                       A risk informed significance determination
           process is being developed for ISI inspection results,
           and NRC's findings related to that, and with inspector
           training, we will be providing written material,
           written packages, for inspector training related to
           the new inspection program in October.
                       And formal training will be provided to
           the regional inspectors in February.  In terms of
           steam generator tube leakage, technical guidance is
           being developed and will be provided to the regions
           some time in the very near future.
                       And this has to do with helping the
           regional inspectors oversight of PWRs with steam
           generator tube leak, and help them understand the role
           of the primary to second leaking monitoring in
           assuring steam generator tube integrity.
                       And in the area of steam generator
           performance indicators, we have done some review, and
           a decision was made not to add any new PI related to
           steam generators.
                       And our next bullet has to do with
           conference calls during outages.  The NRR staff will
           continue doing the conference calls with the licensees
           during -- the selected licensees during the outages,
           and we will docket the telephone summary.
                       And we will also formally review their ISI
           results report, which sometimes is called the 90-day
           report.  A steam generator workshop was held with
           stakeholders in February, and the regulatory
           information conference also had discussions on steam
           generator issues.
                       The next slide is a continuation of this
           slide.  Both the task group and the OIG made
           recommendations for some improvements to NRR's process
           for license amendment reviews, and changes were made
           in response to that.
                       As I mentioned before, NEI 97-06, Ted
           Sullivan will provide a detailed discussion on that. 
           Subsequent to Indian Point 2, as you all know, the
           staff stopped its review of NEI 97-06, and we
           recommenced in January of this year.
                       And so a lot of activities are going on in
           that area.  And then a web page was developed and
           being maintained for internal and external access. 
           And risk communication, that has already been
           mentioned on what we are doing.
                       And milestones for ACRS' recommendation on
           the DPO, and we have a much more detailed presentation
           by Jim Muscara as Ted mentioned; and the last bullet,
           as I mentioned before, are future activities.  
                       CHAIRMAN FORD:  Is there a particular
           reason why this NEI 97-06 was put on hold?
                       MR. SULLIVAN:  Dr. Ford, I am going to be
           getting into that.  I plan to cover your question.
                       CHAIRMAN FORD:  Okay.  
                       MS. BANERJEE:  This slide is on the
           management of the action plan.  We will formally
           document completion of each major milestone, and we
           will be coordinating a resolution of issues with
           external and internal stakeholders.  Like all of our
           meetings with NEI, they are open to the public.
                       And the status of the milestones are
           updated, and a complete copy of the milestones is
           maintained in NRR's Director's Quarterly Status
           Report, and an abbreviated version in is the CTM. 
                       The CTM is updated monthly and the QSR is
           updated quarterly.  And the overall management of the
           action plan is the responsibility of the projects in
           NRR.  This completes my presentation.
                       CHAIRMAN FORD:  Maitri, as I look through
           all the milestones and their completion dates,
           starting back from the earliest of these action plans,
           a tremendous number of them are way, way behind, a
           year behind in completion.  Is there a reason for
                       MR. SULLIVAN:  When you say behind, do you
           mean delayed or do you mean scheduled for some time?
                       CHAIRMAN FORD:  Well, in these lists here,
           I see the targeted completion date, and you are way,
           way beyond.  Like NEI 97-06, there is just one, but
           there are many others.
                       MS. BANERJEE:  Like DPO has a lot of
                       CHAIRMAN FORD:  Well, I am just putting
           this in general.  All of them are way, way behind on
           schedule.  Is there a particular reason for this
                       MS. BANERJEE:  As far as I can tell, some
           of the actions are a little bit behind, but in terms
           of scheduling those milestones into the distance or
           future is because of all the activities that needed to
           be completed before we can get there.
                       And that is a considerable amount of work
           that needed to be done, especially in the area of the
           DPO recommendations.  
                       CHAIRMAN FORD:  So it is manpower and
           dollar constriction on completing those?
                       MR. SULLIVAN:  I think that is true, along
           with all the other work that was already in place
           before we developed the action plan. 
                       CHAIRMAN FORD:  Okay.
                       MR. SULLIVAN:  I think the major delays
           are in the NEI 97-06.  A number of other items -- you
           are right -- they did slip, but usually on the order
           of not too many months; and the DPO work, I wouldn't
           characterize it as having been slipped.
                       The schedules were based on the research
           plans that were pretty much in existence when the ACRS
           report came out.
                       CHAIRMAN FORD:  Okay.  Thank you.
                       MS. BANERJEE:  Any other questions?
                       DR. POWERS:  I am curious about the train
           of reasoning that went about to decide that there
           would be no performance indicator for steam generator
                       And I am perplexed in this area because I
           remind myself that steam generator tube rupture
           accidents are risk dominant for a number of plants;
           and bypass accidents in general are risk dominant.  
                       And seldom do you have a more direct
           indicator of risk than steam generator performance. 
           So what was the rationale that went about not having
           a PI for steam generator performance?
                       MS. BANERJEE:  The way I understand it is
           that the staff considered three potential Pis.  One
           had to do with tube degradation, and one had to do
           with integrity of the tube integrity; and another one
           had to do with primary to secondary leakage.
                       The purpose of a PI is to give you only
           indications of things going south, and in the case of
           the first two, they are only information or new
           information is only available during outages, which
           happens every 18 to 22 or 24 months.
                       So the staff concluded after a lot of
           consideration that it doesn't really provide you with
           an indicator in all cases.  And then in terms of
           primary to secondary leakage, the relationship of the
           steam generator performance with the leakage is not
           very clearly established, and we don't even know that
           it could be established.
                       Because like in the case of Indian Point
           2, we have not seen a tremendous amount of leakage to
           happen before an event occurred.  So considering all
           of that, a conclusion was made that at this point we
           don't have a real good parameter which we can use as
           an early indicator of problems.  Does anybody on the
           staff want to add more to that?
                       MS. KHAN:  I think that summed it up
           pretty well.  By the way, my name is Cheryl Khan, and
           I work in materials in the chemical engineering branch
           in NRR.  
                       But that pretty well sums it up as far as
           the main viewpoints, and as Maitri indicated, the
           first two that she mentioned didn't really fit the
           typical type of performance indicator, the parameters.
                       It needs to be an ongoing parameter that
           you are monitoring continuously; and with respect to
           the third one, as she indicated, leakage is not
           necessarily correlated to the real condition of what
           is going on, and to generate as far as how significant
           the issue is.
                       And in fact the issue may be more
           significant compared to the leakages.  So it was not
           felt that that really was an appropriate term to
           monitor a performance indicator.  
                       The ones that we took beyond that was that
           what the performance indicators would have provided to
           us was the capability to take some type of actions if
           there were signs of degradation occurring in the steam
           generators or issues of significance occurring in the
           steam generators.
                       And so the way that we tried to address
           that is through the inspection process in lieu of
           using performance indicators, because it is typically
           an either/or.
                       And so through the inspection process the
           intent is that there are periodic inspections that are
           being performed under in-service inspection procedure,
           and it incorporates with the in-service inspection
           program, as well as steam generator inspection
                       And there are -- there is a means, that
           dependent on the outcome both of the inspection, the
           NRC's inspection, as well as what the licensee is
           finding, that there is the potential to take immediate
           action, meaning further NRC inspection and
                       And we felt that was more appropriate,
           because that is when the degradation and issues would
           be clearly identified, and then we would be able to
           take immediate action if they were significant enough.
                       DR. POWERS:  So from that I conclude that
           the first decision was that since we couldn't get
           information, except for every 18 months or every
           outage, we would take no PI at all.
                       And that the second one is that because
           the correlation between leakage and tube condition,
           which is good enough for the alternate criteria, is
           not good enough for monitoring the plant?
                       MR. SULLIVAN:  Excuse me, but what do you
           mean by good enough for alternate repair criteria?
                       DR. POWERS:  Well, it's used.  The
           correlation is used as part of the alternate repair
                       MR. SULLIVAN:  I think that one of the
           factors that we considered in terms of primary to
           secondary leakage was that the information that was --
           we had originally proposed that we go down that road
           and look, and what we were advised was that it wasn't
           necessary to put this in as a performance indicator in
           order to get that information.  
                       We get that information on a daily basis
           from plants that are experiencing leakage.  And we are
           involved in it in the sense that the regions will
           typically inform us of when the leakage is increasing,
           and they are going to have phone calls with licensees,
           and we get involved in those phone calls.
                       So we really felt that adding a
           performance indicator in this arena wasn't really
           going to substantially add to our ability to conduct
                       MS. BANERJEE:  That is one thing that the
           resident inspectors review in their daily status
                       CHAIRMAN FORD:  Thank you very much.
                       MR. LONG:  This is Steve Long, and I am in
           NRR in the risk assessment group, and I just wanted to
           add something on the relationship for the performance
           indicators and the parameters we measure.  
                       When the reactor is operating the only
           thing we are really getting information on is leakage
           during normal operation.  We don't know what the
           leaking would be if there was an off-normal condition
           because the off-normal condition isn't there.
                       So it is very hard to relate a very small
           operational leakage number to anything that will help
           us figure out what the actual risk at that time is. 
           When we shut down the plants and inspect the plants,
           then we have good information.
                       And the thing that was not mentioned here
           that I want to add is that at that point, if there are
           findings of degradation, we are developing a
           significance determination process for those findings.
                       Those actions go into the action matrix,
           like the performance indicators go into the action
           matrix, for making a decision about how we are going
           to inspect and regulate the plant.  
                       So instead of having a performance
           indicator that is being updated every three months,
           and that only be tied to an observation every three
           months that is not necessarily in any quantitative way
           tied to the risk, we decided to go with the
           determination of significance of inspection findings
           when something is determined not to be needing the
           performance -- you know, the performance on tube
           integrity, leak tightness and structural integrity,
           and that sort of thing.
                       But that information is still going under
           the action matrix, just like a performance indicator
           would, and we are still making regulatory decisions on
           that information.  It is a timeliness thing.
                       DR. POWERS:  And we don't have a SDP for
           these findings right now?
                       MR. LONG:  That is one of the action
           matrix -- excuse me, but that is one of the action
           plan items, and where that stands at the moment is we
           are just signing out a review of what needs to be
           done, and some suggestions that are going down to the
           branch that is responsible for implementing that into
           procedures.  So that is in the process.
                       DR. DUDLEY:  Do you have a feel for when
           that might be available for ACRS review?
                       MR. LONG:  It is supposed to be in ADAMS
           now, but we had a little glitch.  It is going to be in
           ADAMS by the end of the month I promise.
                       DR. POWERS:  Yes, but when can we get it?
                       MR. SULLIVAN:  I previously introduced
           myself as Ted Sullivan, and I am going to be talking
           about NEI 97-06.
                       DR. KRESS:  And you are still Ted
                       MR. SULLIVAN:  Yes.  We have had a number
           of briefings with the ACRS, and I am going to actually
           go through that towards the end of this view graph a
           little bit.  
                       I had gone over this, but I thought it
           would be worth it to spend a very brief time on some
           background, starting with something that I think we
           have started all these briefings with, which is to
           state that the current requirements, particularly as
           imbedded in the text specs, are prescriptive and out
           of date.
                       They go back to the '70s.  These
           requirements are not focused on the key objective of
           ensuring tube integrity for the entire period between
           in-service inspections.  
                       Rather, they are inspection and repair
           oriented, and they don't focus on the time that steam
           generators can operate between inspections and
           maintain safety margins.
                       And recognizing that the staff began
           initiatives in probably the early '90s, beginning with
           a rule making initiative in the mid-1990s that turned
           out not to be a vehicle that we could use.
                       We briefed the ACRS on that in '96, and
           several times in 1997.  We discussed with the ACRS in
           1997 a change in strategy to a generic letter.  We
           proceeded down that path for probably a year or a
                       And at the same time as that was going on,
           NEI was developing its 97-06 steam generator program
           guidelines initiative, and I believe in the '98 or
           early '99 time frame -- I think the '98 time frame --
           we began discussions with NEI regarding putting the
           generic letter on hold, and switching our focus to a
           new regulatory framework based on NEI 97-06.
                       Throughout a lot of 1999, we held meetings
           and discussions with NEI and other industry
           counterparts on a generic change package that was
           being developed.  The generic change package is kind
           of a centerpiece of proposed technical specifications.
                       And we had reached some tentative
           agreement on drafts of the generic change package in
           late '99, and NEI then went through its process of
           issuing it.  It was issued on February 4th of 2000,
           shortly before the Indian Point-2 tube rupture, less
           than two weeks before that.
                       I think as Maitri mentioned, we suspended
           are review after the Indian Point-2  rupture for
           basically two reasons.  One was that our resources
           were devoted or diverted to Indian Point-2 recovery.
                       A lot of staff resources went into
           reviewing the restart plans and the operational
           assessment that Con-Ed was producing and working on.
           Prior to that, we were reviewing and participating in
           NRC inspections related to the Con-Ed steam generator
                       And also some of our staff was diverted to
           the lessons learned task force.  So that was sort of
           reason number one.  Reason number two was that we
           really wanted to wait and see what came out of the
           Indian Point-2 lessons learned, and factor them back
           into the review.
                       So we didn't want to really make a false
           start.  It wasn't that we had a lot of time that we
           were sitting anyway.  The two things came together
           nicely, but we did deliberately indicate to various
           constituents that we weren't going to do the review,
           or commence the review, until the lessons learned
           study was finished and until we had a chance to look
           at it.      
                       DR. SHACK:  Ted, every time we look at a
           license renewal with a steam generator and we look at
           GALL, everybody seems to be using 97-06.  So that
           means that they are under a dual sort of system.  They
           use 97-06 for their own tracking and monitoring
           purposes, and yet they still meet their tech specs
           also?  Is that the way that the system is working now?
                       MR. SULLIVAN:  That's correct.  Licensees
           have all committed in a manner that I think Jim Riley
           could elaborate on if you want, but it is basically an
           internal industry arrangement that every PWR licensee
           is committed to implement NEI 97-06 for a couple of
           years now.  And I think it was at the first refueling
           after January of 1999.
                       DR. SHACK:  Now, how many PWRs are
           actually running under 95-05?  That is, at least for
           their tube support plate degradation, and they are
           really controlled by 95-05 rather than the old 40
           percent through wall kind of thing.  
                       MR. SULLIVAN:  For that mode of
           degradation, yes.  If the controlling document is tech
           spec amendment dealing with 95-05, and it is on the
           order of a dozen plants, I am not sure if that is
                       DR. SHACK:  So there is still 600 mil
           anneal plants that don't use 95-05?
                       MR. SULLIVAN:  Yes, there are quite a
           number, probably on the order of about two-thirds of
           them, I guess.  I mean, I think about half of the
           plants have replaced roughly, and so that is on the
           order of about -- between 30 and 35.
                       DR. SHACK:  Yes, I was just looking at the
           Mil Anneal 600 plants, yes.
                       MR. SULLIVAN:  And that is what I am
           talking about.  About half still have Mill Anneal 600,
           and half have replaced, and a dozen of that 30 to 35
           reactors use generic letter 95-05 for ODSCC tubes or
                       The staff review of the generic change
           package when we commenced that review included a
           consideration of issues associated with the lessons
           learned report.  
                       A regulatory issue summary of 2022, which
           Maitri mentioned, but I will just elaborate very
           briefly to say that it described technical issues that
           came out of the staff review of Con-Edison's Indian
           Point-2 restart assessment, as well as an operational
           assessment of Arkansas Nuclear Unit-2.
                       And that basically led to a mid-cycle
           inspection.  It was not exactly mid-cycle literally.
           It was sort of late cycle inspection, an additional
           inspection, during the summer of 2000.
                       And then we have also considered the DPO
           action plan issues that were developed in response to
           the ACRS report.  I will go over this briefly as it is
           nothing new.  
                       And even as far back as the rule making,
           our intent was to put in place a new regulatory
           framework that has these features that are in bold. 
           That is, that it is performance based, and it
           establishes performance criteria for ensuring tube
           integrity and leaking integrity under normal and
           accident conditions.  
                       So I am going to elaborate a little bit
           more on that later when I get into a brief discussion
           of performance criteria.  Performance criteria are in
           terms of parameters that are measurable and tolerable.
                       The framework is supposed to be flexible,
           in that the methods for meeting the performance
           criteria are up to the licensee.  It should be
           adaptable to changing mechanisms and technology which
           a prescriptive framework would not be.
                       And it is risk-informed to ensure that no
           -- that there is no significant increase in risk
           associated with operational steam generators.  
                       CHAIRMAN FORD:  If you could just go back
           to that last slide.  
                       MR. SULLIVAN:  Sure.
                       CHAIRMAN FORD:  Industrial parlance, would
           you say that this is a stretch goal given the fact
           that you no longer -- that you don't currently have
           Pis, forced steam generators as I understand for
           reasons that were just enunciated.  
                       So this is really a wish list, and if I
           look at the timing on your latest action plan, the one
           that takes into account the NUREG 17.40
           recommendations, you are looking several years out. 
           You are looking 2, 3, 4 years out --
                       MR. SULLIVAN:  Well, in terms of the
           framework --
                       CHAIRMAN FORD:  before you can have this.
                       MR. SULLIVAN:  In terms of the framework,
           not exactly.  I will try and capture the time frame
           that we have in mind.  In terms of the framework
           itself, we are -- and as I will discuss a little bit
           later, we are probably not going to completely capture
           the performance-based element.
                       We will incorporate it, but it won't be
           strictly non-prescriptive.  We still have to work this
           through with NEI, and that is -- our current target
           date for completion is April, and that is probably
                       CHAIRMAN FORD:  After discussing it with
                       MR. SULLIVAN:  Well, our target date for
           reaching resolution of NEI 97-06 is April, and I am
           saying that may be optimistic.  After we reach
           resolution, which will entail some things that I am
           going to talk about later having to do with issuing a
           generic safety evaluation and so forth, the individual
           plants have to send in tech spec amendments to put
           this in place.
                       The tech spec amendment process could take
           up to an additional year.  So just that alone could
           potentially take a year-and-a-half to two years.  In
           terms of the risk issues, I don't think we will
           consider that we fully understand or more completely
           understand risk until the other issues associated with
           what I refer to as the 3.X items in the action plan
           are completed.
                       And the action plan has 1.X, and 2.X, and
           3.X items.  The 1.X are steam generator related, and
           the issues that came out of the lessons learned
                       The 2.X items are the non-steam generator
           related items that came out of the report; and the 3.X
           items are the ones that basically relate to the ACRS
           report on the DPL.  So I am not sure if I have
           confused things by that answer.
                       CHAIRMAN FORD:  And I am sure it is
           because of my lack of understanding of this whole
           process.  But standing back, as I understand it, we
           have got a whole lot of reactors out there with steam
           generators that are demonstratively cracking.
                       We are not too sure how to quantify the
           progress of this cracking because of monitoring
           discrepancies or restrictions, et cetera, and modeling
           restrictions all go into this NUREG 17.40.  
                       We don't have any Pis to tell us right now
           on an ROP basis as to how we are doing. And what you
           are just saying is that this is the wish list of where
           you want to go, but it is going to be the middle of
           next year before we have got the NEI thing reviewed,
           and 97-06 reviewed, and signed off.
                       And the information for this is not going
           to be around and approved without being used legally
           if you like until another 5 or 6 years.  So what
           happens in the meantime?  What is our backup plan?
                       MR. SULLIVAN:  The intent is to put into
           place a new regulatory framework which I am going to
           cover in subsequent slides and describe in subsequent
                       CHAIRMAN FORD:  I'm jumping in.  Sorry.  
                       MR. SULLIVAN:  And the intent is to get
           that in place for every PWR within about a year-and-a-
           half, assuming -- and that schedule is contingent on
           reaching resolution of the outstanding issues with NEI
           and the industry.  I noticed Jim Riley from NEI is
           interested in adding to what I have been saying.
                       MR. RILEY:  Hi, I am Jim Riley from NEI,
           and I am NEI's project manager for steam generator
           issues.  I think a real important aspect of what we
           are doing here is Ted's illusion to an NEI initiative
           that is set in place.
                       So even though the regulatory framework
           isn't there right now, and we are all working towards
           it, the fact is that the plants are inspecting their
           steam generators to a performance based program based
           on NEI 97-06, which involves basically all these
           things that Ted is talking about, the differences, and
           we don't have the tech specs in place yet that give
           the regulatory aspects of what we are doing some
                       But in fact the plants are all committed,
           all the PWRs, to implementing NEI 97-06 and its
           guidelines that are associated with it.  
                       DR. POWERS:  And Indian Point-2 was one of
           those plants that followed this 97-06?
                       MR. RILEY:  That's correct.  I would like
           to point out though that at the time that Indian
           Point-2 did their inspection previous to their problem
           was 1997, and at that point in time they had not
           implemented 97-06 because it wasn't in place at that
                       CHAIRMAN FORD:  Could I ask my colleagues
           have we seen 97-06?
                       DR. POWERS:  Yes.
                       DR. SHACK:  Yes.
                       DR. SIEBER:  Before you take that slide
           down, on the second bullet there, how does one
           determine whether the value of some parameter is
           tolerable or not tolerable?
                       MR. SULLIVAN:  The basic concept there is
           that we have in place concepts -- and as Jim said, in
           NEI 97-06, of being implemented -- related to specific
           performance criteria.  
                       For example, the structural integrity
           performance criteria is that there should be a factor
           of safety of three times normal operating pressure
           against burst, and 1.4 times main steam line break
                       In terms of measuring, the basic concept
           is that you have a qualified NEI sizing technique, you
           assess -- and with suitable uncertainties, you assess
           the condition of the tubes against that criteria.  
                       If you don't believe that you have a
           sufficient understanding of NDE uncertainties, the
           approach is to prioritize the tubes that are most
           damaged by this degradation mechanism and do institute
           testing against those factors of safety, and determine
           whether or not the performance criteria are being
                       In terms of tolerable, the basic concept
           there is to set the performance criteria such that
           there is some leeway that if the performance criteria
           aren't satisfied, you are not falling off a cliff in
           terms of safety.
                       And in terms of leading to spontaneous
           tube ruptures or being vulnerable to main steam line
           break.  Do you want to add to that?
                       MR. MURPHY:  Yes, I can add to that.  This
           is Emmit Murphy from the Materials and Chemical
           Engineer Branch of NRR.  I might also add that when
           considering appropriate performance criteria, we did
           consider the available information on risk.
                       And we considered some of the findings in
           NUREG 15-70 pertaining to risk, and which also
           included an early look at tube rupture accident
           sequences and their impact on risk.  
                       And the conclusion based on the
           information available at the time was that for plants
           maintaining margins at the performance criteria that
           were being proposed that there was not a significant
           risk issue at that point.
                       So whether you were just slightly below
           the performance criteria, or you were right at the
           performance criteria, there is not going to be -- you
           don't cross a critical risk threshold.
                       DR. SIEBER:  Thank you.  
                       MR. SULLIVAN:  I think one of the major
           elements of the NEI 97-06 generic change package is
           the revision to the text spec that is being proposed,
           and we have worked quite a bit with industry to sort
           of get on the same page on this issue, and on this
           part of the change package we are all in agreement on.
                       And that is that it would contain
           basically three new elements that I have outlined on
           this view graph.  The first is to revise the existing
           operational leakage tech spec downward from this
           standard of 500 gpd, which is in the improved
           standard, to 150 gpd, which a lot of plants already
           have in their tech specs.
                       And then secondly there would be a new
           limiting condition for operation, entitled, "Steam
           Generator Tube Integrity," and that would have a
           surveillance requirement to verify that the structural
           integrity and accident leakage integrity performance
           criteria are met in accordance with the steam
           generator program.
                       And then a new administrative text spec
           called "The Steam Generator Program," which I am going
           to talk about on the next view graph.  The new
           administrative tech spec basically has four elements,
           or maybe five, but over five different elements.
                       It starts out by saying that a steam
           generator program shall be established and implemented
           to ensure tube integrity and performance criteria are
           maintained.  It goes on to require that condition
           monitoring assessments of the as found condition of
           tubes be performed to verify that the tube performance
           criteria that I mentioned previously, the structural
           integrity and the accident leakage integrity
           performance criteria, are being maintained.
                       Then it goes on to say that licensees have
           to use NRC approved performance criteria, even though
           those performance criteria are located in the industry
           steam generator program, they have to be ones that are
           reviewed and approved by the NRC, either generically
           or plant specifically.
                       And in a similar fashion, the tech spec
           goes on to say that licensees can only use approved
           tube repair criteria, and NRC approved repair methods,
           whether they are again approved generically or plant
                       And the last section of this tech spec
           deals with tube inspection reports, and that is not on
           the view graph, and that has to do with when reports
           have to be submitted, and what triggers their
           submission, and what they are to contain.
                       As I mentioned, the details of a steam
           generator program would be located outside of the tech
           specs.  The tech specs basically say what I just went
                       As Jim Riley indicated, licensees -- well,
           actually this isn't what Jim indicated.  This is
           something different.  As part of submitting the
           generic change package, licensees will commit to
           developing the steam generator program in accordance
           with NEI 97-06 guidelines.  
                       The difference here between this and what
           Jim Riley said is that this is a commitment to us, as
           opposed to an internal industry commitment.  The top
           tier of 97-06 guideline document provides general
           guidance for a performance based programmatic strategy
           for ensuring tube integrity.
                       And it includes the elements that I have
           towards the bottom of the view graph.  It includes
           performance criteria, tube integrity assessment, in-
           service inspection elements, tube repair limits and
           repair methods, and leakage monitoring.
                       Not the details, but a description of
           those elements of a program, and it is our intent to
           review NEI 97-06 for endorsement as part of the NEI
           97-06 generic change package.  
                       CHAIRMAN FORD:  And all of these, the sub-
           bulleted performance criteria and in-service
           inspection, the metrics for all of those come out of
           the latest action plan that we have got, the
           integrated NRR for such programs?
                       MR. SULLIVAN:  No.  
                       CHAIRMAN FORD:  Where do the metrics come
           forth?  For instance, in the in-service inspection or
           leak monitoring?  Well, specific data and specific
                       MR. SULLIVAN:  The specific approaches are
           in guideline documents that I am going to talk about
           on the next page.  In terms of inspection, for
           example, since you mentioned that, there is a
           guideline document that contains details on matters
           such as what sort of degradation to look for, what
           sort of probes to use.
                       CHAIRMAN FORD:  All right.
                       MR. SULLIVAN:  What type of qualifications
           the inspectors need to have.  In terms of limits,
           limits are in the performance criteria that the
           inspection program will develop the information to
           apply through integrity assessments to determine
           whether or not the performance criteria are being
                       Actual limits are in the guidelines with
           respect to primary to secondary leakage monitoring and
           the actions that need to be taken.
                       CHAIRMAN FORD:  I understand.  
                       MR. SULLIVAN:  So I mentioned NEI 97-06 as
           a top tier guideline, but here are subtiered
           guidelines that are on this view graph, and I thought
           I would give you a little bit of a flavor of the age
           of those documents, because they do vary quite a bit.
                       The steam generator examination
           guidelines, and examination being another word for
           inspection, currently licensees are using Rev. 5,
           which came out in 1997, and Rev. 6 is being developed. 
           And I am going to talk about Rev. 6 a couple of view
           graphs hence.
                       I believe those guidelines first came out
           in the '80s.  They have been around quite a lot time. 
           The tube integrity assessment guideline is the most
           recent, and I believe that came out in February of
           2000.  So that is only a little over six months old,
           in terms of it actually being issued to licensees.
                       The in-situ pressure test guidelines has
           been around about a year longer than that.  The
           guidelines for monitoring primary to secondary leakage
           came out I believe in the early '90s.  I think they
           are up to Rev. 2 of that.
                       The water chemistry guidelines we believe
           came out or first came out in the late 1970s.  And the
           EPRI sleeve and plug assessment guidelines have been
           around for 4 or 5 years.
                       DR. BONACA:  I have a question.  Going
           back to actually slide seven, when you talk about
           performance criteria in '97 or '96, and this is more
           for information, could you give me a feeling for what
           is involved in that performance criteria?  
                       Is it just simply the number of tubes, or
           leakage, or is it also for example the prediction or
           the ability to predict?
                       MR. SULLIVAN:  There are three performance
           criteria.  The operational leaking is probably the
           easiest because that already exists.  The structural
           integrity criterion says that no tube should have --
           I don't know if this is literal in this, but this is
           actually something that we need to discuss further
           with NEI.
                       But the gist of it is that no tube should
           have less than a margin of three against bursts, and
           the margin of three is against normal operating
           pressure, and 1.4 against main stream line break.
                       The accident leakage integrity criterion
           is again something that you have to calculate, and the
           idea of it is that under accident conditions the total
           primary to secondary leakage under accident conditions
           should not exceed one gallon per minute.  Does that
           answer your question?
                       DR. BONACA:  Yes.  I guess what I am
           looking for is there some element that measures the
           ability of the inspections to predict, for example,
           the growth of the number of defects, as well as the
           severity of the indications?  
                       Is there anything, any element, that does
           that in this program?
                       MR. SULLIVAN:  Well, I think I can address
           that, and if I can't, maybe Emmit can add to it.  I am
           trying to figure out where this comes up or whether I
           have already covered it.  
                       I think I already covered it when I talked
           about in-situ, and talked about the administrative
           tech spec requires that licensees perform condition
           monitoring of as found condition of the tubes.
                       In a similar fashion, while it is not
           embedded in the administrative tech spec itself, the
           bases as it is currently written in draft in NEI 97-06
           talks about the basic understanding that licensees
           perform what is called operational assessments.
                       And I had talked about that previously in
           the context of risk 2022, where licensees do
           predictions through calculational techniques, which
           would involve things like growth of degradation, to
           determine how far out in time they can operate and
           still maintain those safety margins.
                       DR. BONACA:  Well, the reason that I am
           asking the question is that to me that is an element
           of performance that I don't measure in leaking, but I
           have a statement on the part of the utility that
           performs these inspections that says based on what we
           do, we predicted that we will not have more than X-
           number of additional tubes, nor more than this number
           of severe laceration.
                       Now, if I get to the next cycle and I find
           that these predictions are good, it gives me
           confidence in the process.  I could say that that is
           a good performance element in their program if
           conversely they come back and they are totally off,
           and there is a much faster growth, and they cannot
           predict, and I would expect that I would measure that
           as an element of performance in their ability to
           support programmatically the steam generators.  
                       Do you see where I am going?  I am trying
           to understand how that --
                       MR. SULLIVAN:  One of the reporting
           requirements that I didn't mention is that when
           licensees don't satisfy their performance criteria,
           they have to report that to us on a pretty short
           schedule.  I am not sure exactly what the timing is.
                       And our intent if that were to occur would
           be to devote additional resources over what we planned
           to understand what is going on with that particular
           plant, and to work with the licensees.  
                       They may not express it exactly the same
           way, but to work with the licensees to make sure that
           we agree with what their plans are for the next
           operating interval.  
                       In the case of ANO-2, we had observed that
           they didn't satisfy performance criteria on a number
           of occasions going back as far as, I think, 1992.  And
           ANO-2 had been on several occasions between then and
           when they replaced their steam generators last
           October, I believe, had done a number of mid-cycle
                       They had planned to only do one mid-cycle
           inspection in their last operating interval, and
           basically because of disagreements that we had with
           the licensee, they agreed to do two mid-cycle
                       So it is not formalized in terms of some
           sort of performance indicator or performance monitor,
           but it is where we devote our resources when we
           observe that licensees are having problems.
                       DR. BONACA:  I still feel that performance
           criteria here focuses -- or I thought, focused
           specifically on the performance of the steam
           generator.  I think that I would like to look at
           elements of the steam generator program, and among
           those there is also this ability of predicting the
           future leakage and somewhere they must be, and I am
           sure that NEI --
                       DR. SHACK:  But you do that, right,
           because he has to do the performance assessment which
           sort of predicts where he is going to be.  And then he
           does the condition monitoring to find out how well his
           prediction worked.
                       I was curious that when he misses that
           prediction, there is a discussion of why he missed it,
           and the result is a change in his assessment
           procedures, or the mid-cycle inspection, or that is a
           kind of an ad hoc thing that you go through when the
           two don't agree?
                       MR. SULLIVAN:  Right.  I mean, one way to
           put it is that we don't typically review operational
           assessments.  That's not something that we do in
           detail, particularly in headquarters.
                       But if there is a missed performance
           criterion, we would at least review elements of the
           operational assessment, and maybe not take it under
           formal review, but in the sense that we would want to
           approve it.
                       But we would probably ask that it be
           submitted, and we would ask the licensees to give us
           briefings on what their understanding is of why they
           missed it, and what their corrective actions are.
                       DR. BONACA:  It seems to me that if you
           really miss it -- I mean, what you are trying to do in
           this performance is to predict if you really meet in
           fact this criterion leakage, and accident leakage, and
           so on and so forth, all through the period of
           operation that they are allowed to go before
                       And if your predictive models are
           incorrect, then you are violating this criterion by
           definition, simply because they have no basis and no
                       So there has to be some -- and you are
           right.  The real problem or has to be a fundamental
           element of performance, I think.
                       MR. RILEY:  This is Jim Riley again of
           NEI.  Let me see if I can explain how the whole
           process fits together.  There is really three
           assessments associated with the steam generator
                       The first is called the degradation
           assessment, and that is done prior to the inspection. 
           And the utility takes a look at what has transpired in
           their steam generator to this point, and evaluates
           what kinds of degradation they have going on, and
           where it is going on, and they plan their inspection.
                       They figure what they are going to see,
           and they plan what probes they are going to use, and
           what places in the steam generator they are going to
           look, et cetera.
                       And that's all based on previous history
           and anticipated degradation.  They then do their
           condition monitoring, which is the actual inspection
           of the steam generator.  They look at what they
           actually have in place.  
                       If they find in their condition monitoring
           that things are going on that they did not predict in
           their degradation assessment, they revisit the
           degradation assessment during the inspection to see
           does this affect my inspection plans, and do I need to
           look in new places, and do I need to use different
           kinds of probes, and what do I need to do to account
           for this.
                       When they finish their condition
           monitoring, the last thing they do is an operational
           assessment, and that is a prediction forward.  If they
           look at what they have got, and what growth they
           experience, and they predict as Ted indicated how far
           can I operate and still be able to ensure that I will
           meet my performance criteria when I next shut down and
                       And that process repeats itself the next
           time they shut down and do a degradation assessment. 
           So there is a feedback mechanism that makes sure that
           they are accounting for what they are seeing with
           respect to what they are predicting, and influencing
           their inspection program accordingly.
                       MR. SULLIVAN:  Okay.  I am going to kind
           of shift focus in a sense for the rest of the
           presentation and start to try to give you some
           insights into what is currently going on with NEI 
           97-06 and some of the problems that we have been
                       At the time that we made the transition
           from the generic letter and fully understood where we
           were going with respect to setting up a regulatory
           framework that was based on an industry initiative, it
           had not been our intent to review and endorse the
           subtier guidelines that I put up a couple of view
           graphs ago, the detailed subtier guidelines.
                       Based on the guidelines that were
           available at that time, we expected significant
           enhancements to industry efforts to ensure tube
           integrity under this program.
                       The staff's expectation was that the
           guidelines would be sufficiently well developed to
           lead to improved tube integrity performance under the
           new framework, bearing in mind that we didn't have all
           the guidelines.  They had not all been issued at that
                       And we had expected, and continue to
           expect, that the guidelines will evolve over time in
           response to technology changes, lessons learned from
           operating experience, and results from various
                       The staff developed a couple of concerns
           more recently though, and in just this past year, and
           I will try to lay out without getting into too much
           gory detail how they came about.  
                       The first one is related to an action plan
           item having to do with conducting a steam generator
           workshop, which we did in February of this year.  And
           in that workshop some of the industry representatives
           discussed draft revisions to the EPRI steam generator
           examination guidelines, Rev. 6 basically, to permit
           inspection intervals for steam generators with
           improved materials, which we didn't have an issue with
           in particular.
                       But we noticed that at least that draft
           has since been revised substantially, but the draft
           had inspection intervals that would go significantly
           beyond Rev. 5, as well as what is in the tech specs.
                       And bear in mind if this has not been
           clear that the approach under the new frame work would
           be to lift the maximum intervals between inspections
           that is in the tech specs, and rely on the performance
           based strategy instead.
                       In one scenario, as I have on that second
           bullet, it would have permitted inspection intervals
           ranging to 22 full power months.  I am not trying to
           put that there as characterizing the proposals.  I
           want to put out kind of one of the extremes that was
           in that proposal, at least that we considered an
                       We also began to have concerns about
           condition monitoring being implemented, and these grew
           out of questions that we were asking licensees in our
           outage phone calls about their bases for performing
           in-situ testing of tubes.
                       We had some concerns that at least in our
           view that in-situ testing wasn't being performed as
           routinely or under situations that we think they
           should have been performed, at least in some cases.
                       And I am not saying that they weren't
           being performed.  Lot of utilities did institute tests
           last outage, but there were some plants that generated
           some concern in our minds who weren't performing any.
                       These concerns basically could be
           characterized as concerns whether or not the tube
           integrity performance criteria would continue to be
           met, and whether conditions not meeting the
           performance criteria would be detected.
                       DR. SHACK:  What control do you have when
           they do a tube test that they pick the worst tube?  I
           mean, I can always pass it by picking the right tube
           to test.  
                       MR. SULLIVAN:  Right.  Well, if the key
           work is control, we don't have any.  But we have I
           think some influence.  Usually when it is evident --
           well, first of all, we only pick the licensees for
           phone calls that we think have the most degradation,
           or that we are particularly curious about.
                       For example, we are going to have a phone
           call with Turkey Point-3 this season.  They have got
           improved materials, but they have been operating for
           quite a long time.
                       We go over the results, and licensees
           generally characterize their worst tubes, and that
           gives us a sense for whether we agree or want to
           discuss further the in-situ testing that they are
           going to do.
                       They also frequently provide us with lists
           of any current measurements, bearing in mind that
           there is uncertainty, but they give us those
           measurements in tables that they are using themselves,
           and they tell us which tubes they are going to test.
                       We have had occasion, and one that comes
           clearly to mind --
                       DR. SHACK:  But you see that list before
           they do the tests?
                       MR. SULLIVAN:  Yes, generally before. 
           Does that answer your question or should I elaborate?
                       DR. SHACK:  That answers my question.
                       MR. SULLIVAN:  We have had some influence
           in the past.  And in the case of ANO-2, for example,
           in the '98 or '99 time frame, there were four tubes
           that we questioned why they weren't going to test.  
                       They indicated that they thought they were
           unbrellaed by previous tests.  We had given the
           uncertainties and we didn't agree with that.  They
           subsequently ended up testing all four tubes, and
           discovered that one of them was at least questionable,
           or inclusive, regarding whether or not they could
           conclude that they had satisfied the performance
                       Okay.  What I wanted to say that is that
           out of the latter concerns having to do with the in-
           situ tube testing, we took on kind of an initiative if
           you will to spend more time studying those portions of
           the EPRI guidelines dealing with condition monitoring,
           and generated a number of concerns.
                       Those concerns are developed in a letter
           that we sent to NEI.  They knew that it was coming. 
           We had had some discussions with them, and it is dated
           August 2nd.  
                       My understanding is that you were provided
           with that many sometime last week.  I'm sorry that we
           didn't get that to you sooner.  The issues relate to
           industry practice that exist under the current
           regulatory framework.  
                       But these are not brand new issues.  They
           are concerns that we have recently generated in our
           own minds.  But they are existing -- they would exist
           under the new framework, assuming that we were to go
           forward with the new framework, which is our intent.
                       These are not issues that we think we can
           settle in a real court time frame, and that's why I am
           talking about it in this kind of context.  We don't
           think that the existence of these issues, particularly
           given the remarks that Emmit just last made, would
           reduce assurance of tube integrity or increase risk
           under a new framework, assuming that the inspection
           intervals don't increase relative to the current
                       And I am going to get into that in a
           little bit, as that is not quite as hard and fast as
           that may make it sound.  In kind of a parallel
           fashion, at least in terms of the bottom line of this
           view graph, we have reviewed most of the industry
           responses to issues identified for the industry in the
           NRC IP-2 lessons learned study.
                       I am sure that you have glanced at that at
           least and noticed that there were quite a number of
           issues in there for industry, as well as for the NRC
                       And likewise for the review that we have
           done, we included some write-ups on those industry
           sponsors in that same letter that I just mentioned of
           August 2nd.
                       These issues primarily relate to EPRI
           guidelines and some of the issues overlap what I have
           been discussing in terms of condition monitoring and
           inspection intervals.  But some of them go beyond
                       A number of those issues still remain
           unresolved, including the issues that extend beyond
           condition monitoring and inspection intervals.  But
           likewise, those issues exist under the current
           framework and will likely continue to exist under a
           new framework.
                       And we don't think that the existence of
           those issues reduce assurance of tube integrity or
           increase risk under a new framework.  Again, assuming
           inspection intervals don't increase relative to
           current requirements.
                       And again I will repeat that is pretty
           hard and fast, and I am going to explain that a little
           bit more in the last two view graphs.  So, in terms of
           conclusions, pending resolution of these guideline
           issues, the staff has concluded preliminarily that it
           can proceed with review and approval of a generic
           change package provided that there are licensing
           restrictions on inspection intervals.
                       And what I mean by that is that we would
           have in mind that the generic change package
           incorporate agreements with industry on appropriate
           prescriptive intervals for inspections that would be
           tailored to the specific material in the tubing, Mill
           Annealed 600 thermally treated and Inconel 690
           thermally treated.
                       And then the idea behind the words
           licensing restrictions would be that changes to those
           agreements would be likewise to performance criteria
           and repair methods, either generically or plant
           specifically, they would need to be approved by the
           NRC.  That is the proposal that we are working on with
           industry right now.
                       DR. POWERS:  I got a little confused.  You
           said Mill Annealed, and then you said thermally
           treated.  Did you mean just thermally treated?
                       MR. SULLIVAN:  No, I meant three different
           materials.  I'm sorry.
                       DR. POWERS:  Oh, so three different
                       MR. SULLIVAN:  The Mill Annealed 600,
           thermally treated 600, and the thermally treated 690. 
           With this approach, we believe that the generic
           package -- I'm sorry.  The generic change package
           would reduce the assurance of tube integrity only in
           cases where longer inspection intervals than currently
           permitted would be implemented without adequate
                       That is just another way to say what I
           have just been saying.  I think the rest of this,
           except for the last bullet, is kind of repeating what
           I just said.  I wanted to go on to a different concept
           to kind of tie a little bit of this together.
                       And to note that on the last bullet that
           we are working with industry to establish a protocol
           agreement resolving outstanding technical issues.  It
           would formalize an approach for interactions between
           NRC and industry when resolving technical issues that
           exist and that will continue to arise.
                       This is not just something to settle NEI
           97-06, but it would be a long term protocol.  Examples
           of the types of issues that we currently would deal
           with under that protocol would be the lessons learned
           issues, and the condition monitoring issues that we
           have been talking about, the risk 2022 issues, and
           that sort of think, and any new issues that might come
           up over time.
                       DR. POWERS:  Could I go back to the next
           to the last bullet.
                       MR. MURPHY:  Yes.
                       DR. POWERS:  And you say you were
           exploring alternatives with the industry, particularly
           for improved tube materials.  
                       MR. SULLIVAN:  I think what we mean there
           is that the proposal that we most recently have been
           discussing with industry would require that -- and
           correct me if I am wrong, Jim, but the Mill Annealed
           600 tubing plants would basically have to inspect
           every refueling outage.
                       And longer intervals that follow a more
           elaborate scheme, depending in part on what the
           material is, and how long the plant has been
           operation, would have maximum intervals longer than
           that, up to three intervals between inspections, or
           three outages or three cycles of inspections.
                       DR. POWERS:  This is what I am struggling
           with, is that -- well, it is very simple.  People say
           690 is a better material.  As far as I can tell, that
           is what they thought about 600, too.
                       I mean, do we have any confidence that
           this material is really that much better, and that it
           is not going to start cracking?
                       MR. SULLIVAN:  Well, I think that there is
           a lot of evidence in this country that 690, which has
           been in plants for close to 10 years, is performing
           much better than the Mill Annealed 600.  But I am not
           sure if that is what you are driving at though.
                       DR. POWERS:  Well, what I am going to say
           is that 10 years ago we probably could have said the
           same thing about 600.  Well, maybe not.  Maybe it had
           to be 20 years ago.  But at some time we would have
           said that.            
                       MR. SULLIVAN:  We would have said that at
           the outset, but the Mill Annealed 600 tubing started
           performing badly from the very outset.  I mean, plants
           were in their first inspection and performing their
           inspections after the first -- maybe you can elaborate
           on this more, Emmit.  You were there at the time.
                       MR. MURPHY:  Well, in fact -- this is
           Emmit Murphy again.  In fact, plants developed leaks
           during the first operating cycle of operation just as
           an illustration of how quickly the problems developed.
                       DR. BONACA:  Well, that was much to do
           with chemistry.  
                       MR. MURPHY:  Well, I can think of one case
           where the crack involved was primary water cracking
           that occurred in the first operating cycle.  
                       DR. POWERS:  I guess what I am driving at
           is how does one go about arguing that 690 allows you
           to go three operating cycles between inspections? 
           Now, it seems to me that if you can say, well, it has
           operated for 10 years, and no problems.  That's a
           pretty good argument for longer cycles.
                       I mean, if it is that empirically based,
           then it is pretty inarguable.  The trouble that I see
           is the potential for it just suddenly starts leaking
           because of this long induction period it takes for
           cracks to suddenly show up on the detection device.
                       MR. MURPHY:  This Emmit Murphy again, and
           I think we shared that concern, and I think that some
           of the operations that we are exploring with the
           industry here that would provide opportunities for
           materials, for plants with the newer tubing material
           to implement longer inspection intervals.
                       And that these prescriptive limits on
           cycle length would give us the level of assurance
           maintaining the tube integrity margins set that we
           have historically enjoyed, and certainly can do better
           than that hopefully by virtue of the expected and
           improved performance of these new materials.
                       MR. SULLIVAN:  Another thing that I might
           add is that the plants -- you know, this is a little
           bit of an elaborate strategy, and we have not tried to
           get into particulars here.
                       But I think if you take some of the plants
           with Inconel 690 that have been operating the longest,
           the current proposal wouldn't allow them to go three
           cycles.  The current proposal would allow them to go
           two cycles, which is basically what the current text
           specs already allows.
                       So it would only be -- I mean, the basic
           idea is that the licensees do a pre-service inspection
           at the first refueling outage, and they would have to
           do another inspection to monitor for things that --
           you know, like wear.  
                       That in loose parts, you can't just say,
           well, that is not going to happen.  And then they
           would move on to a strategy of thee cycles.  I think
           that it factors that in, as well as being based on
           some of the empirical observations that we have had.
                       MR. RILEY:  If I could say something
           again. This is Jim Riley again from NEI.  Another
           consideration that we have put into our guidelines
           again is this degradation assessment that I mentioned
           the last time.
                       The plants, even though they wouldn't have
           to inspect every outage under our scheme, would be
           required to do a degradation assessment every outage,
           and that degradation assessment needs to take a look
           at what has been happening at their plant, as well as
           what has been happening in other plants around the
           industry and around the world.
                       And if there are things going on in these
           other plants with Inconel 690 that wasn't anticipated,
           that has to be taken into account and it has to be
           taken into account from the perspective of how well it
           pertains to their design steam generators, their
           materials, their chemistry, et cetera.
                       But if they feel that this is challenging
           what otherwise would have been their inspection
           interval, they need to be reacting accordingly.  
                       DR. POWERS:  It is an encouraging thought,
           but what is discouraging is when I look at the
           assessments under the maintenance rule, one of the
           areas that the licensees found most challenging was
           the ability to take into account experience within the
           industry, and not at their own facility.
                       So, pardon me, but I would be just a
           little skeptical that they will -- that in the
           assessment that they won't be looking for ways to
           argue what is going on some place else just doesn't
           relate to my plant.
                       MR. RILEY:  That's difficult to argue.  I
           mean, obviously it depends on an individual plant, but
           I will say this.  That there are plenty of information
           available to the licensees, in terms of what is going
           on elsewhere.  
                       We have an industry organization that
           meets three times a year and shares operating
           experience.  We have a steam generator degradation and
           steam generator database that EPRI maintains that
           keeps track of what is going on at different places,
           in terms of tube degradation, and tube pulls, and tube
           information, et cetera.
                       We have organizations within the industry
           that do reviews of steam generator programs at various
           -- well, they rotate through all the plants, and do an
           evaluation of how well they are conducting their
           program with respect to what the requirements are in
           NEI 97-06 and other places.
                       And we have internal peer reviews that are
           done between organizations, and all these things are
           intending to look at how a particular utility is
           conducting its steam generator program with respect to
           the norm and the expectations.
                       And sharing with plant management cases
           where they feel that they are not meeting the industry
           standards on these issues.
                       MR. SULLIVAN:  One thing that I might add
           for what it is worth is that over the years when a new
           degradation mechanism is identified, or not
           necessarily a mechanism, but a new location, and we
           learned about it in a phone call.
                       And we might be on the phone call at the
           same time, or the next day, or whatever, with a
           similar plant, and we would bring it up in the phone
           call, and I can't remember a single time that the
           licensees weren't already aware of it. 
                       And I think as Jim indicated, the
           networking is pretty strong, and had modified their
           inspection plans to look for it if it was applicable,
           just in the "for what's it is worth department."
                       CHAIRMAN FORD:  Can I just ask a question,
           more on a technical management aspect?  Do I
           understand that right this instant, in terms of
           monitoring the performance of the steam generator
           tubing, that we are essentially using NEI 97-06
           procedures, regardless of how they stand within the
           regulatory framework right now?
                       And that in very short order that you are
           going with this generic change package, which is based
           on NEI 97-06, but with modifications associated with
           its memo that you sent out on the 2nd of August?
                       And that would give some regulatory aspect
           to approval if you like.  It may not have gone through
           all the sign-offs, et cetera, et cetera, that you may
           have to do.  But essentially you have got regulatory
           approval for the NEI 97-06 procedures, et cetera, and
           that is in the short term.
                       MR. SULLIVAN:  Yes.
                       CHAIRMAN FORD:  And for the longer term,
           as we go through the question of brisk assessment of
           the delta-LOCA and the delta-LERFs, and modifications
           to your current understanding of those parameters, and
           that will come out in later years as a result of this
           joint NRR research program.  How I got the sequence of
           events right?
                       MR. SULLIVAN:  I think that's correct, and
           then depending on what comes out of that, we may have
           to factor it back into our understanding, and/or our
           regulation of the steam generator programs.
                       CHAIRMAN FORD:  Now, is it appropriate
           therefore in the short term, if you are going to have
           this model one of this generic change package in
           place, is it appropriate to have a presentation to
           this subcommittee -- and let's say in December -- so
           that we understand at least the technical pros and
           cons of this process?  
                       MR. SULLIVAN:  I think it is a good idea.
                       CHAIRMAN FORD:  And I stress the technical
           aspects.  For instance, what the pre-inspection
           assessment methodology is, and what is the
           uncertainties in it, et cetera, so that we understand
           the impacts on safety.
                       MR. SULLIVAN:  I think coming back for
           another presentation is a good idea.  The only thing
           that comes to mind is that we are also making a
           presentation to the Commission on December 4th.  So we
           want to make sure that we don't have a conflict there.
                       CHAIRMAN FORD:  I have no idea what the
           constraints of this particular aspect is --
                       MR. SULLIVAN:  As a concept, I think it is
           a good idea, and we did anticipate that you want more
           technical details than what we are talking about
                       CHAIRMAN FORD:  Okay.
                       MR. SULLIVAN:  This is just kind of an
                       DR. DUDLEY:  Just thoughts.  Would it be
           more appropriate for an ACRS presentation before or
           after the presentation made to the Commission?
                       MR. SULLIVAN:  Can I get back to you on
           that later?  I would like to talk to my colleagues.
                       DR. DUDLEY:  Yes, that is something that
           you need to work out.
                       CHAIRMAN FORD:  But this is a joint
                       MR. SULLIVAN:  Yes.  Sure.  We will have
           to coordinate with Jim, of course.  I can't speak for
                       CHAIRMAN FORD:  Excellent.
                       MR. SULLIVAN:  But they have been willing
           in the past to come and make presentations like this.
                       MR. RILEY:  Jim Riley again.  We would be
           happy to join your presentation on the technical
           aspects of the program.
                       MR. SULLIVAN:  Okay.  I just have a couple
           of comments.  I have kind of covered this, but I just
           wanted to make sure that it is clear that we do plan
           to develop a safety evaluation on this whole generic
           change package. 
                       The vehicle for issuing it would be a
           regulatory issue summary, and the proposal would be to
           put it out for public comment before we finalize it. 
           There are some specific reasons that we want to do
           that that we can get into now or in the next
                       Our target date had been the end of next
           month, and we clearly see that we are not going to
           make that.  We are hoping that we can get this done in
           April of 2000, although I have to admit that was kind
           of an arbitrary projection that we could get it done
           within about six months.
                       We are still working with NEI on technical
           issues, as well as the regulatory issue having to do
           with regulatory controls.  And so I am not sure just
           how optimistic or achievable the April date is.  
                       And as I mentioned before, this same sort
           of data is contingent on coming to terms with this in
           the pretty near term, because there are a lot of steps
           that we need to go through, in terms of things like
           issuing a risk for public comment, and finishing the
           safety evaluation, and so forth.  So that concludes my
                       CHAIRMAN FORD:  Thank you very much.  I
           would like to put this on hold for 15 minutes, and I'm
           sure that on hold isn't the right word, but we will
           take a tea break.
                       (Whereupon, the meeting was recessed at
           10:08 p.m. and resumed at 10:25 p.m.)
                       CHAIRMAN FORD:  Okay.  We are back in
           session, and we are reversing the order.  Ken is going
           first, and Joe is coming second.  So, Ken will be
           talking about the South Texas project.
                       MR. KARWOSKI:  I am going to stand during
           this, just because I need to point to some of the
           stuff on the view graph.  My name is Ken Karwoski, and
           I am with the Materials and Chemical Engineering
           Branch in NRR.
                       My presentation is broken into two parts. 
           The first part will be the overview of the South Texas
           steam generator operating experience, and the second
           part will get into the last part of the presentation,
           which is some of the issues on the -- with respect to
           the differing professional opinion.
                       So the slides are in the opposite order
           that I had anticipated.  So we will skip the first two
           slides, and I will come back to those at the end of
           the presentation, and I will start with South Texas.
                       South Texas is a four loop pressurized
           water reactor.  It has a model E-2 steam generators
           and there is about 4,900 tubes in each of those steam
           generators.  They have Alloy 600 mill annealed tubing,
           with the exception that there is 15 tubes in one of
           the steam generators that is made of Alloy 600
           thermally treated.
                       They did that, I believe, to test for
           whether or not this material would be any better. 
           They have three-quarter inch diameter tubes, which is
           important for generic letter 95-05.  The tubes are
           supported at various elevation by drilled holes
           stainless steel tube support plates.
                       That is a little different than most of
           the mill annealed plants.  Actually, it is the only
           plant in the country that has drilled hole stainless
           steel tube support plates.  
                       The bulk of the plants that use generic
           letter 95-05 have carbon steel drill holes tube
           support plates, and I will talk a little bit about
           that later on.
                       DR. POWERS:  What is the potential
           difference between the stainless steel and the Alloy
           600, the electrical-chemical potential differences?
                       DR. SHACK:  There's not much.
                       DR. POWERS:  But just about everything is
                       DR. SHACK:  Well, it is certain less than
           carbon steel.
                       MR. KARWOSKI:  But the key with the
           stainless steel, which I will get into, is that it is
           less corrosion resistant in a steam generator
           environment.  So what you have with the carbon steel
           tube support plates is those tend to corrode and tend
           to fill the crevice with magnetite, which tends to
           impact the tubes, and actually cause corrosion-induced
                       The stainless steels are less susceptible
           to corrosion in the steam generator environment, and
           you don't get that type of corrosion product build up
           in the crevice which could restrict leakage and can
           bend the tubes.
                       There have been other plants in the
           nuclear industry, particularly Doel 4 and Tihange 3,
           which ave these types of tube support plates.  The
           steam generators at those plants have been replaced.
                       At South Texas the tubes have been
           hydraulically expanded into the tube sheet, and the
           expansion transitions were shortened to reduce
           susceptibility of corrosion.
                       R-1 and 2 of the steam generators went
           through a U-bent heat treatment to also reduce the
           suspectibility of corrosion of the R-1 and 2 U-bends. 
           South Texas, coming on line later, implemented several
           enhancements to their steam generators in order to
           reduce the susceptibility of the tubes to --
                       DR. SHACK:  Well, it is awful late for a
           Mill Annealed plant though? 
                       MR. KARWOSKI:  I think they started
           commercial operation in like '89, but when they
           ordered their steam generators and when they planned
           that, I don't have that information.
                       But, yes, in the overall sequence of
           events, if you look at some of the earlier
           replacements, they were thermally treated in the early
           '80s.  And so I am speculating that they must have
           ordered them. 
                       DR. SHACK:  They must have decided that
           they didn't need to do that.
                       MR. KARWOSKI:  Yes.  Of particular
           interest here is that in their pre-heater area, they
           expanded several tubes as a result of a concern of
           tube wear that had been observed in Westinghouse Model
           D steam generators, and I would just point this out
           there because they have observed some corrosion there
           or some damage at that location.
                       And that is because of the cross-flow of
           velocity of the feed water entering the steam
           generator.  South Texas has a T-hot of approximately
           625 degrees fahrenheit, and that is one of the higher
           ones in the country, which just exacerbates some of
           the corrosion problems that they may be observing.
                       At the end of Cycle 8, which was in March
           of 2001, they  had approximately nine effective full
           power years on their steam generators, which is not a
           lot of time.
                       The primary degradation mechanism is
           actually oriented outside diameter stress corrosion
           cracking at the tube support plates, the focus of
           Generic Letter 95-05.
                       I just briefly want to discuss some of the
           other degradation mechanisms that they have been
           observing.  They have detected some free span outside
           diameter stress corrosion cracking, primarily
           associated with dings.
                       I use the term "dings" because instead of
           corrosion-induced denting, it is more damage as a
           result of fabrication.  
                       DR. POWERS:  What is the gap width for
           this drill hole plate in the tube wall roughly?  
                       MR. KARWOSKI:  I think the exact value is
           proprietary, but it is on the order of less than a
           tenth of an inch for the normal support plates.  They 
           have a flow distribution baffle, which I think is on
           the order of a tenth of an inch, which has an enlarged
           tube hole opening.
                       And that is the first support plate
           elevation, and in general they have not observed as
           much degradation at that location than they have at
           the higher locations, where the diametrical clearance
           is less.
                       DR. POWERS:  What I am trying to
           understand is that because we don't have this included
           hole in the plate are we getting what would be crevice
           type chemistry changes in there, in that hole region?
                       MR. KARWOSKI:  Can I answer that a little
           later on?
                       DR. POWERS:  Sure.
                       MR. KARWOSKI:  But that is one of the
           theories that might be happening with respect to the
           operational leakage.  But I will touch upon that later
                       So they have had free spanaxial outside
           diameter stress corrosion cracking, and they have also
           detected some free span volumetric indications, and
           they have detected some of these over the course of
           the last cycle or the cycles prior to that.
                       CHAIRMAN FORD:  I wonder if you could just
           mention -- and maybe you will mention it later on, but
           the question of the difference between the stainless
           steel and the carbon steel floor plates, the fact that
           there is generally less corrosion product, and
           therefore that would have an impact on leak rates.
                       MR. KARWOSKI:  I will get to that in
           probably 3 or 4 more slides.
                       CHAIRMAN FORD:  Okay.  Good.
                       MR. KARWOSKI:  New mechanisms that they
           observed during the March 2001 outage, they detected
           some indications that the hot leg expansion
           transition, that's not unusual for a plant with Alloy
           600 Mill Annealed.  
                       The indications were primarily OD.  They
           did find some ID indications of one ID indication. 
           The licensee speculates that the shop cleaning may
           have been effective in reducing some of the ID
                       Some of the dings in their steam generator
           are basically separated by about three-quarters of an
           inch, which is the thickness of the tube support
                       They believe that as they inserted the
           tubes into the steam generator that there was some
           bending moment that caused what they called paired
           dings.  At one of those paired dings, they observed
           circumvential cracking at one location and axial
           cracking at the other.  
                       They found a Row-1 new bend indication,
           which was outside diameter stress corrosion cracking. 
           They also found cracking at the U-Bend transition, and
           they found a volumetric indication at the expansion
           transition of one of those tubes expanded in the pre-
                       Most of these degradation mechanisms are
           common among plants with 600 Mill Annealed tubing. 
           The licensee has currently plugged about 9 percent of
           the tubes.  Their licensing basis limit, I believe, is
           10 percent.  The are scheduled to replace in December
           of 2002 at the end of the present cycle.  
                       DR. SHACK:  Do they sleeve or do they just
           plug every one?
                       MR. KARWOSKI:  I think they just plug.
                       DR. SHACK:  With respect to the voltage
           based repair criteria, I did mention that that is
           their primary degradation mechanism, and they first
           implemented Generic Letter 95-05 during Cycle 7, which
           was in the '98-'99 time frame.
                       They were approved for a one-volt repair
           criteria at that time.  As a result of that amendment,
           they analyzed for 15.4 gallons per minute primary to
           secondary leakage during a steam line break to
           demonstrate that the off-site builds consequences
           where acceptable.
                       And during this review that the staff
           approved that limit.  Cycle 8, the licensee also
           implemented the one volt repair criteria, and in Cycle
           9, which is the cycle that they are presently
           operating in, they recommended a 3 volt repair
                       That repair criteria had been used at
           Braidwood and Bryon, and evasively what it involves is
           demonstrating that the motion for the tube support
           plants is limited such that the degradation at the
           support plate will not be exposed during a steam line
                       And which allows them to go to a larger
           voltage limit because the probability of burst will be
                       DR. SHACK:  Now, I noticed that South
           Texas gets the benefit from IRB technology, as well as
           the three volt limit.  Did Braidwood and Bryon get the
           IRB technology, or did they just live with 00 votes.
                       MR. KARWOSKI:  By the IRB, the indications
           are that that methodology, although the value of what
           we assigned to those --
                       DR. SHACK:  The probabilities, the 10 to
           the minus 5? 
                       MR. KARWOSKI:  Right.  Both South Texas
           and Braidwood, and Bryon had to model URDs in their
           methodology to account for the potential that a tube
           attempts to burst, but can't because of the presence
           of the plate, and therefore the leakage could be
           higher.  Braidwood and Bryon had to model that and
           South Texas also.
                       DR. SHACK:  They got to use 10 to the
           minus 5th, first, and then two, as well as the three
           volts?  When we say the three vote criterion, I never
           realized that you got a double-benefit.
                       MR. KARWOSKI:  Okay.  Let me take a step
           back.  When you implement this methodology,
           essentially by locking the support plate in place, you
           have essentially -- for an axial crack, you basically
           prevented it from fully opening or fully achieving
           burst because of the diametrical clearances.  
                       Because of that the probability of an
           axial rupture, that could be on the order of 10 to the
           minus 5th.  I don't recall what the actual number is,
           but they basically modeled what the probability is for
           a burst given the amount of displacement of the plate.
                       In addition, they have a correlation which
           they say, okay, now that I can potentially go to
           higher limits, what is the probability that I tear
           this tube and get a circumvential break?
                       And that's how they would -- they would
           generate a limit for that.  The industry would claim
           that that limit, that you could tolerate 10 volt
           indications, and the staff said 3 volts based on that
                       And so they also modeled the probability
           that you would get a circumvential failure of the tube
           at the location.  So there is two parts of that
                       Now, the URDs, that is basically a leakage
           model aspect, and basically in the leaking
           correlation, basically they don't have indications
           which try to burst and actually leak excessively.  
                       So as part of the three volt amendment,
           Braidwood and Bryon embarked on a testing program to
           figure out, okay, how that I have got these higher
           voltage limits, if this tube starts to open up how
           much will it leak given that the plate is there.
                       And that is what the URDs do, is that it
           is another leakage correlation that is tacked on above
           the normal free span leak rate correlation.  So in
           Cycle 9, basically in February or March of this year,
           we approved this 3 volt criteria, and the licensee
           expanded tubes at tube support plates 2, 3, and 4 in
           order to limit the motion.
                       They only chose these lowe support plates
           because that is where most of the degradation is
           occurring.  And I will talk a little bit more of how
           they actually implemented that repair criteria during
           this last outage.
                       During their past cycle, Cycle 8, prior to
           implementing this 3 volt repair criteria, the licensee
           was observing primary to secondary leakage in all four
           steam generators, for a total of about --
                       DR. SHACK:  Excuse me, but can I just --
           this IRB is confusing me again, because as I read this
           thing, when they do what I thought was a 95-05
           methodology, which ignores the restricting from
           bursting, they exceed the 10 to the minus 2
           probability of failure.
                       Then they have to go to the IRB thing, and
           that gets them down to 1 times 10 to the minus 3.  So
           it is not an additive thing.  They don't use the 3
           volt criteria for the plates that are locked; is that
           the way that I am interpreting this?
                       MR. KARWOSKI:  For the plates that are
           locked, basically they say how far will the plates
           move, or could they potentially move, and if I were to
           expose a crack of that length throughout that plate,
           and for all the plates in the steam generator which
           have applied that criteria, what is the probability of
           burst of that axial crack.
                       DR. SHACK:  Okay.  So that is saying that
           we understand the movement of this plate well enough
           that 10 to the minus 5th is the product of the
           probability that the tube will burst without the plate
           times the probability that it will be uncovered,
                       MR. KARWOSKI:  It is more of just the
           materials issue.  It is just that you have to
           understand how much the plate is going to move.  So
           that aspect is in there.  
                       You have to know how much of the crack
           will be exposed or could potentially be exposed,
           because we are postulating that the crack is at the
           tip of the support plate, and as the support plate
           moves it exposes the entire flaw over that length.
                       DR. SHACK:  But they had to calculate that
           probability somehow from their fluid mechanics
                       DR. KRESS:  They just assumed it happened.
                       MR. KARWOSKI:  But they assume all -- they
           calculate the maximum displacement of the plates.
                       DR. KRESS:  And then they assume it
                       MR. KARWOSKI:  And then they assume it
           occurs over the entire plate, and so basically they
           are saying, okay, I have exposed -- I think in their
           case they postulated that -- or they determined that
           it would meet something on the order of .15 inches.
                       And so they said .15 inches for every tube
           at that plate.  They didn't say that the plate is
           going to move .15 inches here, and .12 inches here,
           and .02 inches here.  They just assumed that the
           maximum displacement for every intersection.
                       DR. KRESS:  How did they make that
           determination?  Do you know?
                       MR. KARWOSKI:  The determination of how
           much it would move?
                       DR. KRESS:  Yes.
                       MR. KARWOSKI:  That is by thermal
           hydraulic modeling.
                       DR. KRESS:  So you don't have a
           probability associated with that then?
                       MR. KARWOSKI:  There is no probability
           associated with that.
                       DR. KRESS:  So the probability of the
           materials isn't --
                       MR. KARWOSKI:  Right.
                       DR. SHACK:  So what you are saying then is
           that if I uncover a tenth of an inch, say, I can
           somehow calculate then the probability that he burst
           will be 10 to the minus 5?
                       MR. KARWOSKI:  Yes.  I think in general
           they say less than 10 to the minus 5.
                       DR. SHACK:  And how do I do that?
                       MR. KARWOSKI:  Well, basically you have a
           crack that extends outside the plate, and so the plate
           is constraining the crack, the bolt of the crack. 
           Let's assume it is a three-quarter inch long crack for
                       And I move the plate .15 inches, and so I
           have got 6/10ths of an inch crack within the plate,
           and .15 inches outside.  
                       DR. SHACK:  Do I do this on a mechanistic
           fracture mechanics basis rather than on a voltage
                       MR. KARWOSKI:  Yes.  Yes.  Basically, how
           much support does the plate give, and what the vendor
           would argue is that the plate basically -- that the
           length of the exposed crack is what is dominating the
           probability of burst. 
                       So basically you can say, well, what is
           the probability of a .15 inch long flaw bursting.  It
           is based on mechanistic and it is not voltage.  It is
           not voltage.
                       CHAIRMAN FORD:  So can I have just a time
           sanity check here?  We are required to have a letter
           on the DPU issue at the next ACRS meeting.  How long
           do you think at this current rate of progress do you
           think it will take?  Can you be finished by 11
                       MR. KARWOSKI:  Yes.  
                       CHAIRMAN FORD:  Provided that we don't ask
           too many more questions.
                       MR. KARWOSKI:  Right.  
                       CHAIRMAN FORD:  Okay.  
                       MR. KARWOSKI:  Okay.  So they were
           observing leakage in all four steam generators, and
           when they came into the outage, they did a secondary
           side pressure test, where they filled the secondary
           side up with water, and pressurized it to something on
           the order of 600 pounds.
                       And then they monitored for leakage on the
           primary side of the tubes, and looked for drippage
           from the tubes.  What they found was that none of them
           were leaking excessively, but there were some tubes
           approximately that were damp.  
                       The leakage was attributed to outside
           diameter stress, corrosion, cracking, at the support
           plates, and that is important because no other
           domestic plant has ever observed operating leakage as
           a result of cracking at the tube support plate
                       And that gets back to various theories of
           why we haven't observed leakage, and one of the
           theories is that as the carbon steel support plates
           corrode, they form magnetite, and the magnetite gets
           into the crevices and impinges -- well, impinges isn't
           the word.
                       But it forms magnetite and the magnetite
           fills the crevice, and it will start denting the tube
           and basically or essentially would seal the crack. 
           That is one theory.  
                       So that the crack tries to leak, and it is
           not very porous, and it doesn't get out.  That is one
           of the theories that has happened.  And the stainless
           steel tube support plates situation in South Texas,
           you don't have that magnetite filling the crevice, and
           you have might scale on the outside of the tube, and
           still have a crevice.
                       And so you are still observing the
           corrosion, but in this case it is not impeding the
           flow of the crack.  That is a theory.  As I mentioned
           before, South Texas, too, is the only domestic plant
           with stainless steel tube support plates, drilled hole
           stainless steel support plates.
                       And Doel-4 and Tihange-3 had that.  Doel-4
           had exhibited leakage coming from the support plates
           during a similar secondary side pressure test in the
           early '90s.
                       Because of the concerns on operational
           leakage, although the licensee was authorized to
           implement a three vote repair criteria, they
           preventively plugged down to approximately 1-1/2 volts
           because of those concerns.  
                       They did some depth-sizing of some of
           these flaws to determine which ones that they thought
           may have been most likely to leak, and they prevently
           plugged those.
                       After the outage and these results became
           available, the license submitted their 90 day report. 
           It is basically a summary of inspection activities
           primarily related to Generic Letter 95-05.  
                       The staff reviewed that report and we
           identified several issues that we asked the licensee
           to address.  And the issues are on this view graph,
           and I would just like to illustrate them.  
                       One of them is the ability to predict end
           of cycle conditions, which I believe was one of the
           concerns raised earlier this morning.  There are two
           things that we look for during these reviews, and that
           is the number of indications predicted, reasonable,
           and is the severity, and in this case is the voltage
           of the indications reasonable.
                       What this table shows is that it shows the
           four steam generators and also the total, and it shows
           the three cycles where they implemented the voltage-
           based repair criteria.  
                       For each one of these cycles, they show
           the projected number of indications that they
           determined, and then the actual.  In this first cycle,
           you will notice that they under-predicted the actual
           in one of the four steam generators, but in general
           they were conservative, with the exception of Steam
           Generator C.
                       DR. POWERS:  And before I leap to that
           conclusion, I guess I would ask you how many
           indications were in these steam generators that they
           failed to detect?
                       MR. KARWOSKI:  This actual number does not
           include any account for the probability of detection. 
           So this number here and the assessments that they do
           is basically assuming that you are finding the more
           severe flaws.
                       And that the flaws that you are not
           detecting are not of structural leakage significance
           even now, and that they would not be of structural
           leakage significance at this point.  This number does
           not account for that.
                       DR. POWERS:  Okay.  But if I take my
           probability of detection at .6, and they then do it
           for everything?
                       MR. KARWOSKI:  Right.  But this is more of
           a condition monitoring assessment.  This number here
           would be -- would include the .6 from the prior cycle,
           but yes, you are right.  The value of .6, remember, is
           to account for two things.
                       It is not only to account for indications
           which we missed during the inspection, but also for
           new indications which may develop or initiate over
           that cycle.  So to adjust these by .6 in a condition
           monitoring system --
                       DR. POWERS:  It is not quite fair, but to
           adjust it by some number is fair.
                       MR. KARWOSKI:  Yes, but what we would

           argue is that what they missed is probably not --
                       DR. POWERS:  I don't think you can do
           that.  I mean, I think you have a database that says
           there are flaws of substantial size --
                       MR. KARWOSKI:  That's true.
                       DR. POWERS:  And you have a plant up in
           New York where that is definitely true.
                       MR. KARWOSKI:  That is true.  That is
           true.  So this number does not include any -- it is
           basically what they found in the steam generator
           during that inspection, and it does not account for
           any improbability of detection.  
                       CHAIRMAN FORD:  All those numbers, the
           right or actual numbers, should be multiplied by 1.4
           or whatever the number is?
                       DR. POWERS:  I don't think it is quite
           fair to do it that way.
                       MR. KARWOSKI:  No, no.
                       DR. POWERS:  As he pointed out the .6
           counts for other things.  But there is some number
           that they should be multiplied by.
                       CHAIRMAN FORD:  Correct.
                       MR. SULLIVAN:  And that multiplication
           factor is used in the projections forward. 
                       MR. KARWOSKI:  Right.  So to arrive at
           these projected numbers, what they did is they took
           the actual, and divided by .6, and subtracted off the
           number that they repaired, and that's how many they
                       The purpose of this is just to show the
           number of indications and the probability of
           detection, and you need both the numbers and the
           severity of the degradation. 
                       DR. SHACK:  So when we see these cases
           where the actuals exceeded the projected that is
           extremely distressing
                       MR. KARWOSKI:  Let me phrase it this way. 
           In general, for Generic Letter 95-05, one of the
           criticisms that the industry has always said is the
           POD of .6 is excessively conservative, excessively
                       So when you typically look at these 90 day
           reports, you typically see numbers like that.  In the
           case of South Texas --
                       DR. POWERS:  You see numbers like C.
                       MR. KARWOSKI:  Right.  And if you just
           look at the total numbers, you start saying that
           things are getting pretty close, and if you look at
           the last cycle, they under-predicted the number of
           indications in two of the four steam generators.
                       Now, that may not be bad in and of itself,
           because if I am just finding a bunch of low voltage or
           indications which have no structural or leakage
           significance, that may not be a problem.
                       But this is just one piece of the puzzle. 
           Next, the next graph addresses the severity of the
           indications, and basically it is a similar table to
           the previous one.  
                       It shows the steam generators, and as
           voltage goes up the severity of the indication
           increases and we compare it projected to actual.  And
           in general if you just look at the totals, in this
           case they under-predicted the number of larger voltage
           indications in the first cycle, but the number was
                       The second time they also under-predicted
           and the same thing for this third cycle.  As a result
           of this, we are pursuing discussions with the licensee
           to ask them to address it.  
                       And in the interest of time, this last
           view graph just shows that the average growth rate,
           that if you look at Cycles 6, 7 and 8, the growth rate
           has been increasing the average growth rate, and that
           pretty much is supported by the previous table.
                       There are some other issues that we have
           asked the licensee to address regarding leakage
           observations.  During the inspections, they had done
           some in-situ pressure testing, where they insert a
           device inside the tube, and pressurize it to determine
           whether or not it is going to leak and/or burst.
                       And they observed some leakage during
           those tests, and given that the in-situ tests are
           typically done on the worst tubes, from the
           information that we were provided, it doesn't seem
           like those results indicate or could account for all
           the operational leakage that they observed.
                       And so we have asked them to take a look
           at that.  So basically the last view graph, here the
           next step is that we post these issues to the
           licensees, and they are monitoring for operational
                       And there has not been any observed
           presently and the licensee plans to replace their
           steam generators at the end of the current cycle.  
                       DR. BONACA:  Well, you started to say
           something about after you looked at the severity of
           indication, because of this, we asked the licensee --
           and then you didn't complete the phrase.
                       MR. KARWOSKI:  We have asked the licensee
           that in light of these results, basically tell us why
           the methodology is working for your plant.  What
           confidence do you have that we will be able to
           actually project what is going to be on this steam
           generator at the end of the next cycle.
                       DR. BONACA:  Well, it seems to me that
           they are under-predicting both, in terms of severity.
                       MR. KARWOSKI:  That's true, and in some
           cases that may not be a concern.  If I am calculating
           leakage of a 10th of a gallon per minute during
           accident conditions, and I have under-predicted the
           number of severity, that may not be a problem in and
           of itself.
                       But in this case, they are, and in one of
           their generators they are projecting leakage which is
           approaching that 15.4 gallon per minute.
                       DR. BONACA:  Plus, there are a number of
           indications that are going so fast and that is really
           what we are transmitting.  And at that point you begin
           to wonder about when do you get to that point where
           you have a critical change in the leakage, for
                       MR. KARWOSKI:  Right.
                       DR. SHACK:  Now, when they do the
           operational assessment what will they use for the
           average growth rate?  Will they project that
           increasing curve, or will they use the observed --
                       MR. KARWOSKI:  They will use the
           methodology that is called for them to use, and the
           most conservative over the last two cycles, which I am
           assuming was the last cycles, and so they will use the
                       And the reason for showing you the tables
           of the -- of what I will call the increase in growth
           rate is that that is certainly one of the issues that
           the staff would like addressed, which is, is the
           methodology working.
                       And that is basically the reason or could
           be a reason why they have under-predicted the severity
           of some of those indications.  At this point, I would
           like to move to the second part of the presentation,
           which basically addresses two of the ACRS'
           recommendations on the differing professional opinion.
                       The two recommendations that I want to
           discuss are the seven-eighths inch diameter leak rate
           database, and the recommendation with respect to flaw
                       With respect to the seven-eighth inch
           diameter leakage database, the ACRS indicated that the
           database needs to be greatly improved to be useful,
           and that the staff should consider requiring a near
           term expansion of that database.
                       The staff agrees that the seven-eighth
           inch database does not exhibit as strong a correlation
           as the three-quarter inch.  To refresh everybody's
           memory the three-quarter inch database has
           approximately 50 pull tubes, and about half of which
           come from pull tubes.  
                       The seven-eighths inch database on the
           other hand only has approximately 30 data points, of
           which only around 25 percent, or seven or eight data
           points are from pull tubes.
                       So the staff agrees that this seven-
           eighths database has a weaker correlation.  With
           respect to whether or not the expansion of the
           database will actually improve the correlation, as
           part of getting ready for this presentation, I tried
           to do that assessment by looking that as they added
           data over the course of several years, and what has
           happened in general.
                       And based on a very simplistic evaluation,
           which I did, it looks like the correlation is staying
           the same, or maybe getting slightly worse.  So even
           though they added data, it has not necessarily made
           the correlation better.
                       But the correlation in 95-05 does address
           how to handle it if the correlation -- you know, if
           there is a correlation or if there isn't any
                       With respect to adding more tubes, the
           staff recognized when they issued Generic Letter 95-05
           that the limited data then -- and it is still
           recognized as it is now, that the results as part of
           the methodology that licensees committed to a tube
           pull program, either the one that is in the generic
           letter, or an industry developed the tube pull
                       And with this protocol the utilities
           periodically pull tubes, and the focus of those pulled
           tubes is for seven-eighth inch diameter tubes is the
           leakage database.  They need more data and the
           industry recognizes that.
                       With respect to -- with the exception of
           this commitment, there is really no other regulatory
           vehicle and the methodology to require removal of
           additional tubes.  But the staff will continue to
           monitor the effects of additional data as more data is
           added as a result of these tube pulls.  
                       The next recommendation that I want to
           talk about is flaw growth.  The recommendation was
           that the staff should establish a program to monitor
           the predictions of flaw growth for systematic
           deviations from expectations, and that the staff
           should develop a database on predictions, and observe
           voltage distributions.
                       As part of Generic Letter 95-05, we asked
           the licensees to submit the data to the NRC to permit
           putting together -- or to permit the staff to do these
           comparisons of predicted and observed voltage.  
                       And I think that the South Texas example
           that I just went through is one of those cases where
           we do look at that when we do those reviews to
           determine whether or not there is something that we
           need to follow up on.
                       So we have and we will continue to review
           the 90 day reports with that recommendation in mind. 
           That was the reason for requesting that information to
           be provided to the licensees.
                       We recognize that it is an empirical
           approach and we need to continually assess how well we
           are doing with respect to our predictions.  The staff
           is formalizing the review of inspection summary
           reports, which the 90 day reports are a subset of, in
           conjunction with the steam generator action plan, Item
                       And there have been instances where the
           predictions have been non-conservative, and South
           Texas is one of them.
                       DR. POWERS:  As part of this
           formalization, you are going to explain how to use a
           probability of detection to adjust the numbers that
           are sent to you, right?  I mean, you have got to deal
           with the probability of detection issue don't you?
                       MR. KARWOSKI:  Right.  
                       DR. POWERS:  Okay.  One of the ways of
           dealing with it is to say that I am not going to deal
           with it, but I think that would be fairly
                       MR. KARWOSKI:  We can definitely look at
           it as -- and whether or not it gets into formal review
           or whether or not that is more detailed guidance --
                       DR. POWERS:  Well, how do you handle it?
                       MR. KARWOSKI:  Yes, we need to realize
           that there are some indications which you can miss.
                       DR. POWERS:  I think Westinghouse put
           together a pretty nice story on what the probability
           of detection is for what we needed in this context,
           and which strictly is a probability of detection.
                       CHAIRMAN FORD:  There is a question of
           probability of detection, but the efforts that you are
           doing in this area is combined in our own research,
           and is in the 3.6 of the NUREG program.  That's in
           addition to this one isn't it?
                       MR. KARWOSKI:  I am not -- with respect to
           the database, the database is basically a regulatory
           issue; whether or not research plans that I am doing
           additional testing under these model boiler or
           laboratory produced specimens that could supplement
           the database, if they develop any of that type of
           data, would gladly include in the correlation if it is
                       With respect to the flaw growth, I don't
           know if research is going anything on this issue.  The
           recommendation was more looking at how the
           predictions, compared to what we observed in the
           field.  And so it gets more into how well is my
           operational assessment performing. 
                       CHAIRMAN FORD:  I am not surprised that
           you are not firming up on your correlation, and just
           adding more uncontrolled data or bad data is not going
           to improve your correlation plan.
                       MR. KARWOSKI:  Right.  But that's -- 
                       CHAIRMAN FORD:  You can have as many bad
           data points as you like, but that is not going to help
                       DR. POWERS:  I think they made a case for
           the pulling and that it wasn't doing too much to it,
           and a case gets made when you say, gee, the three-
           quarter inch data gets pulled just the same way, and
           it doesn't look all that bad.  
                       What is there so unusual about the seven-
           eighths, and it is kind of hard to imagine that there
           is something different about pulling one.
                       CHAIRMAN FORD:  So as we go down this
           path, and then you realize that you are not going to
           improve the correlation factors, what is your fall
                       MR. KARWOSKI:  I don't necessarily want to
           say that we won't improve the correlations, but --
                       CHAIRMAN FORD:  I guess at this point that
           you had better recognize it that you probably won't. 
           So what is your fall back?
                       MR. KARWOSKI:  Well, if the statistical
           criteria are not met to demonstrate that there is a
           correlation, the Generic Letter 95-05 methodology says
           that if you can't demonstrate that, then you need to
           calculate your leak rates in accordance with the
           following procedure, which basically says that the
           leakage is independent of the voltage observed.
                       So there is a methodology that already
           accounts for that, because back then when we were
           doing the 95-05, some of these databases didn't have
           a correlation, and so we had to deal with that back
           then.  So there is a fall back in the methodology.
                       CHAIRMAN FORD:  And thank you very much
           indeed.  At this point, is that your presentation?
                       MR. KARWOSKI:  That's it.
                       CHAIRMAN FORD:  Thank you very much. 
           Mario has to leave at 11:30, and the next talk is by
           Joe, and who should be talking about some of the
           further DPO issues and the new research program. 
           Mario, before you go, would you like to make any
           comments on what you have heard so far?  
                       One of the issues that we have to address
           is what is the next action as far as this subcommittee
           is concerned, and we are going to write DPO a letter
           for the next ACRS meeting, and we have suggested that
           in the November-December time frame that we have a
           presentation by NEI/NRR on the 97-06.  
                       Do you have any comments on what you have
           heard so far?         
                       DR. BONACA:  The only one that I mentioned
           before regarding performance, and the issue of
           prediction that has already been discussed now.  That
           is the only point that I think we want to stress is
                       And also this consideration of what do you
           include in the predictions.  I mean, what should you
           consider a multiplier to that.  
                       CHAIRMAN FORD:  Thanks so much.  And you
           like the idea of having a meeting in the November-
           December time frame?
                       DR. BONACA:  Yes.  I would like to see if
           and when we have a new presentation that there would
           also be more focus on the objectives of this
           integrated plan.  
                       I mean, one thing that I was left with was
           that I think I understood the objectives of the NEI
           program, and while clearly stated, for the integrated
           plan I heard that the objective was to integrate the
                       And still I think it would be nice to have
           a statement somewhere of what is the purpose of
           reintegrating all these activities.  We understand it
           generally, but often times if you state what the
           objectives are, then it focuses better on the plan
                       And I would have liked to have seen that
           in a statement at the beginning of the presentation. 
                       DR. KRESS:  Our obligation is just to have
           a letter on the DOP issues?
                       DR. BONACA:  Yes, for right now.
                       DR. KRESS:  And some of the other things
           that he is talking about would be just a briefing?
                       CHAIRMAN FORD:  A briefing to this
           subcommittee in November or December.
                       DR. BONACA:  That's right.  That is just
           a suggestion for the briefing, yes.
                       DR. DUDLEY:  I would like to think that if
           we did do a review of the 97-06 letter that the
           committee would comment back to the staff on it in the
           letter in December.
                       DR. KRESS:  Combine in the same letter as
           the one on the DOP issues?
                       CHAIRMAN FORD:  We are going to do that
           next week.
                       DR. KRESS:  Oh, you are going to do that
           next week?
                       CHAIRMAN FORD:  Yes, if we have enough
           information, and if we don't have enough information,
           we can't comment.
                       DR. KRESS:  Okay.  
                       CHAIRMAN FORD:  Okay.  Thanks very much.
                       MR. MUSCARA:  Thank you, Peter.  My name
           is Joe Muscara, and in June of this year the EDO sent
           a letter to the ACRS transmitting the action plan that
           included DPO issues.
                       That plan is updated monthly and is
           available to you.  So the status is really available
           within that plan.  So what we thought we would do for
           this meeting was to more or less concentrate on the
           near term milestones.
                       So we will try and cover some of the work
           that has completed in the past year, and address work
           that will be going on for about the next year.  In the
           presentation, I will start off discussing some of the
           issues related to materials, engineering, and
                       And then Charlie Tinkler will give us an
           overview of the severe accidents and thermal
           hydraulics work; and Steve Bajorek will discuss some
           thermal hydraulics calculations for predicting the
           loads during a steam line break.
                       And Chris Boy will provide us some input
           on some CFD calculations that have been conducted
           recently.  Under 3.1 of the action plan, the history
           of crack propagation in steam generator tubes under a
           steam line break condition, and we have planned some
           work in this area to essentially start in the new
           calendar year, 2002.
                       What we will be doing there initially is
           to obtain some loads, including cyclic loads, during
           the MSLB from thermal-hydraulic calculations, and this
           will be covered in a bit more detail later.  
                       At the same time there has been an
           analysis conducted, and we have submittals in this
           area, and so we will also plan on reviewing those
           submittals, and try to obtain some of the loads form
                       We will put together what we think will be
           the bonding loads experienced by the tubes during the
           MSLB, and based on that we will calculate the crack
           growth, if any, for a range of crack types and sizes
           using the loads as determined above.  
                       CHAIRMAN FORD:  The crack growth is just
           tearing, and not sub-critical crack growth?
                       MR. MUSCARA:  That's right.  We will
           assume that we have some existing cracks, and then we
           have the accident, and then we will determine whether
           these cracks propagate or not.
                       As far as the ranges of crack sizes,
           clearly we would like to look at initially at a crack
           that is stable under normal operating conditions.  But
           it would be unstable under the steam line.  
                       So with this largest crack, we can one
           that will still not propagate a leak.  And then we
           will take that crack size and determine whether that
           would propagate under the steam line break conditions. 
           But we will look at a range of crack sizes.
                       CHAIRMAN FORD:  Will we be coming back to
           discuss some of the details?  For instance, what -- as
           I understand it, calculating the delta-Ps by some of
           the existing hydraulic codes is not necessarily an
           easy thing.
                       MR. MUSCARA:  Right.
                       CHAIRMAN FORD:  So will we be discussing
           some of the technical challenges and back up if we
           can't meet those challenges?
                       MR. MUSCARA:  Right.  The discussion that
           follows will address that issue.
                       CHAIRMAN FORD:  Okay.  Good.
                       MR. MUSCARA:  Another approach that we
           will take is to also estimate the loads that are
           required to propagate existing cracks.  And based on
           that we can determine some margins, and what is the
           margin over the MSLB loads.  
                       In fact, if we find that we have large
           margins, then we really don't feel that we need to
           refine the thermal-hydraulic calculations.  If in fact
           the margins are not so large, then we have to refine
           the calculations again, and that will be discussed
                       And having conducted these analyses, and
           we will be using existing procedure for evaluating the
           burst and leakage, and mostly burst in this case, we
           will then conduct some tests to validate these
                       So then the tests will then take into
           account not only the pressure stress, but also the
           bending loads and the cyclic loads, and that work will
           be done at the beginning of '03.  
                       CHAIRMAN FORD:  Again, the question of the
           movement of the plates and things of this nature. 
           This is again a fairly -- in calculating these loads,
           it is not a trivial exercise at all?
                       MR. MUSCARA:  Right, and so again what we
           are doing there is we will do some of our own
           calculations, and the thermal-hydraulics will be
           described, and we will look at what the industry has
           provided us.
                       And we will come up with some upper bound
           estimates, and then we will use those loads to
           determine what happens to cracks.  And if we find that
           we have small margins, then we will need to do
           additional work to refine the analysis.
                       And another item that is covered in the
           operating plan, and also of course addressed in the
           ACRS report was damage progression by jet impingement,
           and this is jet impingement both under severe accident
           conditions and jet impingement from a steam line
                       Last year, in October, about this time of
           the year, we presented some information on the jet
           impingement work under severe accident conditions to
           the ACRS, and at that time we were more or less agreed
           that jet impingement from severe accidents from the
           aerosols are not really a problem.  There is very
           little erosion that goes on.
                       And the ACRS suggested that we may want to
           look at a somewhat longer term test.  Our initial
           tests were 10 minutes, and we have conducted some
           additional tests based on the recommendation.
                       DR. BONACA:  Let me just ask a simple
           question.  Going to page four, you have or you
           mentioned that starting in 2003 that you will have a
           test on the tubes under pressure and axial bending. 
           Why are you waiting so long?
                       I mean, wouldn't you want to have results
           as you do calculations, and that mostly likely,
           especially in doing hydraulic calculations, you raise
           a question insofar as the modeling, and whether or not
           certain effects are being properly modeled.
                       MR. MUSCARA:  Well, the test that I am
           talking about is mechanical tests to validate our
           analysis.  The analytical methods have been developed
           and proven over many years.  So we don't believe that
           the validation tests are going to give us a different
                       Our main emphasis is going to be using the
           procedures already developed, and in most cases it
           will be a flow stress model for essentially the
           failure criterion.  We will also be using some
           fundamental analysis on the structural side.
                       DR. BONACA:  It is only a test, and it
           going to be purely --
                       MR. MUSCARA:  It is a validation test just
           to confirm that the analysis was proved.
                       DR. BONACA:  And that is dealing with
           tubes and some force applied to.
                       MR. MUSCARA:  Right.  The tests that we
           have conducted so far in the models that we have
           developed have been mostly pressure stress.  So we
           want to add to those pressure stresses some of the
           bending loads.
                       And with the bending loads and axial loads
           one might see with the support plates moving what the
           tubes are doing in terms of support plates.
                       DR. BONACA:  And you said that this
           analytical method or models that you are going to use
           already are credible for this kind of test?
                       MR. MUSCARA:  Yes.  We conducted back in
           the '80s 800 tests with different types and sizes of
           flaws to predict failure of these tubes.
                       DR. BONACA:  And so you are talking about
           the analysis now, and I am talking about the analysis.
                       MR. MUSCARA:  Yes.  Well, based on those
           tests, we developed analytical procedures and those
           have been validated.  And tests have been conducted in
           other parts of the world that confirm those methods.
                       DR. BONACA:  And these are analyses as you
           mentioned are computer codes that you are going to use
           to perform these analyses?
                       MR. MUSCARA:  Most of the analysis will be
           under stresses, and the evaluation of MSLB, which is
           a parameter that describes the stress on the ligament
           of the crack.
                       DR. BONACA:  I guess I am asking because
           I am kind of surprised, and I just didn't know that
           you already had all this information, and models
           available, and they were not being used to address
           this issue of main steam line break.
                       MR. MUSCARA:  Frankly, if you consider
           axial flaws, for example, and we think that this might
           propagate under steam line break conditions, I don't
           believe that is credible.
                       I mean, these tubes have got so much
           toughness, and it would need to have so much pull to
           propagate those flaws that the tube would fail as if
           the flaw wasn't there, and it would take a great load.
                       Now, the other conditions are when we
           would have circumvential cracks, and in those
           conditions it would be somewhat a little bit
           different.  I still believe that based on the work
           that we have done that it is going to take a great
           load to open up these cracks enough to cause a major
                       For example, we find that cracks that are
           270 degrees around the tube all the way through still
           will not open up and give you a large leakage.  So I
           guess that part of the reason that we haven't done
           these tests is because that we have felt from an
           engineering feeling that the steam line break loads
           will not propagate these kinds of cracks.
                       And with respect to cyclic loads, yes, we
           have some cyclic loads, but how long are these loads
           going to be on there.  Again, I don't think we have
           enough cycles to affect the growth of existing cracks. 
           But we will do the work and see where we are.
                       On the jet impingement work as I
           mentioned, we have work that is ongoing on both the
           aerosol impingement and from a steam line break.  The
           work on the aerosols was conducted at the University
           of Cincinnati with Professor Tabakoff, and the jet
           erosion tests have been conducted at Argonne National
                       And I think I mentioned that the rest of
           the items we have conducted tests now of up to 30
           minutes for the aerosols.  Dr. Ford, if we are
           stressed for time, I could skip the view graph here. 
                       DR. POWERS:  My feeling is that you can
           skip over the erosion results.
                       MR. MUSCARA:  Well, I guess the final
           outcome of that is that the 30 minute test did not
           provide us any different data.  We still have very low
           rates, about 2 mils per hour with just nickel, and
           about 5 mils per hours with nickel, plus aluminum.
           And these are much  more severe conditions than the
           actual aerosols. 
                       DR. POWERS:  And I kind of assumed that
           was the results that you were going to get.  
                       MR. MUSCARA:  In fact, the data was really
           indistinguishable from the prior data.  All right. 
           And some results that we haven't shown are test
           results on the jet impingement and steam line break
                       Here essentially we have run some tests
           with the different sized holes, but concentrating on
           the 1/32nd inch hole.  There is a specimen spot weld
           to the leaking tube, with a stand-off distance of
           about a quarter-of-an-inch.  So the leaking tube
           impinges on this group. 
                       We conducted tests as a function of
           temperature, and we find that the most degradation is
           obtained at about 280 degrees centigrade, which is
           about the cold leg temperature, and where you don't
           expect to see cracks.
                       And then the amount of erosion decreases
           as the super heat goes up, and so as the temperature
           goes up.  So we are getting some flashing and not as
           much penetration.
                       The greatest amount of penetration we had
           was about 25 percent of the wall over a two hour test
           period.  And we will move now on to some comments on
           the NDE.  There was a comment in the ACRS report that
           using a constant POD may not be the best thing.
                       We have been doing work in this area for
           a number of years, and last year again I described
           work on a mock-up.  We have now some results, and I
           think I will go into showing some of the results from
           the round-robin analysis of the mock-up.
                       CHAIRMAN FORD:  Joe, I asked the question
           to Ken Karwoski about the interrelationship between
           the work being done by research on this item, and it
           being transitioned into use.  Can you make a comment
           on that?
                       MR. MUSCARA:  Well, let me give a little
           bit of background.  We issued this work about 5 or 6
           years ago, and at that time I was looking for a
           physically based model that we could use for doing the
           operational assessments.
                       The big concern was that we were using for
           the voltage based criterion, and it is empirically
           based, that there is no physical reason why it should
           give us good correlations.  
                       Voltage does not relate to crack size. 
           Therefore, it cannot relate to crack growth, and crack
           growth cannot relate to burst pressures.  Generally as
           the voltage goes up, the crack size goes up, but there
           is a general correlation.
                       What is not true is that for low voltage
           that it is not just small cracks.  We are going to
           have big cracks that have a low voltage.  So in my
           mind what was needed was something that was more
           robust and more physically based.
                       So at that time we conducted an
           operational assessment.  We needed to know the
           probability detection so that we can take into account
           the flaws that were missed during inspection, and we
           needed to know something about cracking issues and
           what happens during the cycle.
                       And of course we needed to know crack
           growth grade, and not based on voltage, but based on
           some physical parameters.  And so at that time we set
           up work to learn more about these items.
                       And one of the key areas of work then was
           the probability of detection.  So by the time the ACRS
           had their comment, we already had done a considerable
           amount of work trying to develop POD as a function of
           different parameters.  
                       And also this data is available.  It is
           available for us, and it is available for the
           industry, and it can be used as people see fit.  We
           tried to conduct these tests in a realistic way.  We
           are using procedures that are used in the field, and
           we tried to limit the entire inspection processes
           conducted in the field.
                       We have done the degradation assessment,
           and we have the right techniques, and qualified
           techniques, and qualified people doing the
                       We have a five-person team that has done
           the inspections, and so we have tried to reproduce as
           much as possible the process that goes on in the
           field.  With respect to the tubes and the division
           itself, the same thing.  
                       We developed a fairly comprehensive mock-
           up with different conditions of dents, and corrosion
           products, and transitions, and realistic flaws,
           developed in the lab with realistic flaws from the
           point of view of signal, and so we believe that we
           have a reasonable test.
                       And we do have now some results that may
           be POD to some other factors besides the --
                       CHAIRMAN FORD:  Am I missing something? 
           That although you have this data, it is not being
                       MR. MUSCARA:  Well, this data is just
           evolving.  In research, the main emphasis is to
           develop also a code that can be made available to the
           NRC staff so they can do their own independent
           operational assessments.  POD is one input to this
           code, and precision crack code would be another code.
                       So that code is under development and the
           data is becoming available, and our first topical
           report will be published before the end of this year
           providing these results.
                       And of course the results have been made
           available, and we have reviewed the draft reports, and
           so we are aware of the information.
                       CHAIRMAN FORD:  So we are ahead of the
           ball game here on this particular result?
                       MR. MUSCARA:  Yes, I think so.
                       DR. POWERS:  The ad hoc committee -- I
           think you have to understand that the NRR staff has a
           different set of problems.  They need to detect and
           then they need to predict, and they need to predict
           what kinds of things show up in between the two.
                       What the ad hoc committee was concerned
           was about was using a constant POD with respect to
           carbon stone was that as the technology for sampling,
           for inspecting tubes improved, and as the technical
           understanding improved, you wouldn't be able to
           correct things, and take into account, and it is a
           draconian thing.
                       So when we moved to something that was
           more easily corrected, and that is all that this
           research is doing, and it was basically an endorsement
           of this research. 
                       MR. MUSCARA:  In fact, the Generic Letter
           95-05 made some comments at that time, and they in
           fact did say that they felt that the voltage raised
           criterion is acceptable for now, but we should be
           moving towards more physically based criterion.
                       And the ACRS said that, and so based on
           that also we felt a need to develop this kind of data. 
           The results were that the upper left figure shows the
           POD is a function of depth, and for flaws at the tube
           support plate, both for the OD and the ID.
                       Quickly, we noticed that the ID flaws are
           more easily detected if the POD is higher, and that is
           reasonable because we get in general larger signals
           from the ID than from the OD.  There is not as much
           penetration of the ID currents.
                       In the next view graph we are showing a
           similar plot, but with respect to voltage, and we see
           here that the role is reversed.  What I need to
           mention is that once the voltage gets considerably
           high, all the POD get to be about the same.
                       But for lower voltages, we are getting a
           better correlation with the OD flaws.  At one point,
           for the ID flaws, we also had the dents.  So many of
           the flaws at the support plate that were originally
           from the ID also had a dent.
                       That means that we had a signal which was
           not very clean.  Now, because the inspector looks at
           the signal rise on the plane to a vertical position
           for calling it a crack, and because there is a dent
           signal, and because ID flaws only have a small range
           of phase angle shift, the signal does not rise very
           much, and can also be buried in the noise.
                       So in this case the ID flaws showed a
           lower POD than the ID flaws.  But this shows in
           general that we can plot that POD is a function of the
           depth of the flaw, and POD is a function of the
                       And the bottom graph essentially shows POD
           for the tube sheet section, where we have a couple of
           tube sheet flaws also with the tube transition, the
           role transition being present that complicates the
                       Besides looking at the flaw size, flaw
           size and voltage by itself, a very useful parameter to
           plot the PODs as a function of MLSB, and again MLSB
           describes the stress at the ligament of the flaw.  It
           directly relates to the burst pressure.
                       So here we can relate POD as a function of
           a structural integrity parameter, and we noticed that
           the POD gets to be reasonably high if LIDSCC parameter
           of greater than 2.3 would correspondence to a flaw
           that would fail at 3 delta-P.  So the POD for cracks
           that are at 3 delta-P can be fairly high.  
                       And just to show it from the view graph
           and to make an other point that even though our
           results are qualified, what we noticed for certain
           conditions, such as the tube sheet, and the top two
           graphs, we are plotting the results on a team-by-team
           basis.  The others were combined results.
                       And we noticed that the teams more or less
           cluster fairly close together for those two examples,
           but in other cases -- for example, the free span,
           where the teams are not use to looking at the flaws of
           the free span, they find lots of flaws on top of the
           tube sheet and support plates, and not so much at the
           free span.
                       And also for the support plate for the
           LIDSCCs, there is quite a bit of scatter in the team
           performance.  The good team is quite good, and the
           number of teams right there is sort of an average.  
                       But there is always a team that does not
           perform as well, and again I would like to stress that
           these are teams that are commercial teams, and they
           are qualified, and they are conducted in inspections
           in a manner that is similar to what they do in the
                       And if anything of course they know that
           they are under test conditions, and so this is under
           best performance.
                       CHAIRMAN FORD:  And the lines on these
           grants -- I'm sorry, but what are they?
                       MR. MUSCARA:  They are just a different
           team.  The assembles are a team and also the line is
           also a team.  So we had 11 teams participating in this
           round robin.
                       CHAIRMAN FORD:  Oh, I see.  
                       DR. POWERS:  The best team and the worst
           team had to change lines, and everybody else --
                       MR. MUSCARA:  And it is just a logistic
           thing.  So we are showing you essentially the variance
           between the best and the worst team.  I mean, this is
           very useful data when we are doing probablistic
                       So I think more or less we have addressed
           the issue for ACRS as to other methods may be useful,
           and we already have data in this area.  There is one
           item that I would like to cover --
                       CHAIRMAN FORD:  I'm sorry, but I am
           violating my own principle of not asking questions,
           but if you would go back to the bottom right-hand
           slide, the IDSCC tube support plate and the biggest
           scatter.  Is that purely because the cracks are on the
           ID and the eddy can't pick those up for some reason or
                       MR. MUSCARA:  No, because one thing is
           they are doing quite well if you look at the green
                       CHAIRMAN FORD:  Yes, but the scatter.
                       MR. MUSCARA:  Well, yes, the scatter, but
           what is the complicating factor of course with these
           flaws is that there is a role transition, and that
           role transition provides a fairly large signal.
                       CHAIRMAN FORD:  Oh, so you have a float
           between the --
                       MR. MUSCARA:  It is a complicated signal,
           although --
                       DR. SHACK:  But this is the tube support
           plate there though?
                       MR. MUSCARA:  I'm sorry?  Oh, yes, this is
           the ID with the dent.  So you do have considerable
           noise, and some things do better than others.  I think
           here again that it is a matter of -- there may be a
           signal there as a matter of calling it a crack.
                       And because the signal is more and doesn't
           have a large shift-in phase, and there is a
           complicated noise signal, it still is difficult for
           the inspector to notice it to call it a crack. They
           may confuse it as being part of the noise signal.  But
           the good inspectors do quite well.
                       And this next view graph is not really at
           all to do with materials.  I see that Jack Hays is in
           the back of the room and he can answer any questions
           on this.  
                       This is the item on the item spiking.  We
           have conducted an assessment of the ADAMS and Atwood,
           and Adams and Sattison spiking data this summer, and
           I understand that this review has been completed.  
                       And the plant having a response to the
           ACRS comments by December, and our evaluation of this
           will be published for public comment around February,
           and then based on the public comment, there is a final
           position that will be put together.
                       I understand that after we evaluate our
           position on this issue that we could be willing an
           able to provide a presentation to the ACRS on that
           position before it goes out for public comment.
                       So I think this is something that is up to
           you if you want to hear about this or not after we
           have assembled a position on it.
                       DR. POWERS:  Comments are always the same. 
           That is more work than it would take to solve the
           problem completely.  Do it the way that you want to,
           but that is an awful lot of work for a problem that I
           think is susceptible to a technical resolution.
                       MR. MUSCARA:  Jack, do you want to
           respond?  No?  Okay.  Well, I am almost finished,
           because the next view graph is milestones and is
           fairly far into the future, but there will be work
           going on next year in this area, and I know that Peter
           will be interested in this.
                       So I decided to discuss this a little bit. 
           Now, we are planning on conducting some tests to
           better understand the crack initiation and crack
           growth.  And we are taking the comments from the ACRS
           to heart.  We want to conduct tests under realistic
           conditions of stresses, temperatures, and environment.
                       That means that we need to evaluate better
           what goes on in crevices.  As far as the tests
           themselves, they are not defined yet, but we may be
           using model boilers so that we can reproduce the
           thermal hydraulic conditions and the crevice
           conditions, and therefore, have the appropriate
           crevice chemistry.
                       We may have to measure the crevice
           chemistry, and we may just run tests and evaluate the
           cracking behavior, and then measure the crevice
           chemistry at the end when we are not at operating
           conditions anymore.  But it is very difficult to
           instrument these crevices.
                       So there are a number of ideas that we are
           considering.  The work is not defined, but we will be
           looking at crack initiation, and crack growth, and
           using tubular specimens, along with other types of
                       And hopefully under realistic fuel
           conditions, and the idea here again is not necessarily
           to develop the mechanisms, but to develop data that
           will be useful for our code for doing the assessments,
           the operational assessments.  And we need crack
           initiation data and crack code data.
                       DR. POWERS:  A couple of questions, Joe. 
           As people move to 690 are you going to be testing 690?
                       MR. MUSCARA:  Yes, thank you.  We will be
           testing 690, along with the 600.  The idea here is
           that we have a great deal of information on the
           behavior of 600 in the field.  
                       So we will be conducting tests with 600
           mill anneal, and 690 thermally treated, so that at
           least we know the behavior in the laboratory; and then
           knowing the behavior of 600 in the field, hopefully we
           can extrapolate the behavior of 690.
                       It may be well that on 690 to just make a
           couple of comments.  Now, 690 is susceptible to
           cracking in different environments.  It has cracked in
           the laboratory, and cracks in environments that are
           not overly aggressive.  It cracks in neutral solutions
           and sulfates, and in copper, and in lead.
                       So what we want to do is with respect to
           690 to evaluate the range of conditions under which
           this material is susceptible so that we can get a
           better idea about its behavior in the field.
                       In addition to this, we have had Professor
           Staley working on crack initiation.  This work was
           just started about a year ago, and he is modeling
           this.  But we have also been looking at some of the
           field data.
                       When we look at the data for 600 mill
           anneal, and we consider the cracking that we are
           experiencing these days, and not necessarily the
           caustic cracking that we got in the early days.  
                       We will consider cracking at the support
           plate and crevices.  Well, 600 mill annealed has taken
           10 years before it experiences this kind of cracking. 
           So the fact that 690 has gone 10 years doesn't give me
           that much more comfort yet.  
                       We know that in the laboratory that it
           behaves better, and I do believe that it will behave
           better, but I don't know whether it will last 40
           years.  But through this work hopefully we will get a
           better feeling for the behavior of 690, as compared to
                       DR. POWERS:  Another thing that I noticed
           -- and as you say, trying to instrument to understand
           what is going on in crevice corrosion -- and probably
           because it is small, and things just don't fit in
           there -- I noticed that within the corrosion community
           there are people -- I mean, crevice corrosion is not
           peculiar to nuclear plants.  It is a lot of places.
                       But there are people who are trying to
           develop what they call scaling laws for crevice
           corrosion.  In other words, to do experiments that are
           scaled where you can instrument, and then you try to
           find out how does that scale down to the real
           crevices.  Are you paying any attention to that kind
           of work?
                       MR. MUSCARA:  Well, actually there is work
           also going on related to steam generators.  Jesse
           Lumpson at Rockwell Science Center is doing some work
           for EPRI, and he has been doing work for a number of
           years having a typical crevice.  
                       And he has done quite a good number of
           studies himself, but also this crevice model has been
           taken to a plant in Japan, where they are conducting
           tests using the coolant from the plant.
                       So they are developing good model data,
           and we will take advantage of that.  My feeling is
           that we will still need to run some model boiler
           tests, where we reproduce the crevice under thermal-
           hydraulic conditions, and see how the materials
                       We will try to research it as much as
           possible.  Some of the things that we can certainly
           get are temperature, and maybe potential, and maybe
           MPH.  It would be interesting to be able to get
           chemical species, and that is a harder problem.
                       EPRI is working on it and they may in fact
           by the time we are ready to do something have some
           solutions on how to do that experimentally.  But one
           thing that we can fall back on is what is in the
           crevice after we have shut down the system.  That will
           give us a clue as to what was there in the operating
                       CHAIRMAN FORD:  I have a couple of
           questions, Joe.  On Task 3.8, that relates to the
           whole question of how can you correlate a bonding, a
           linear correlation of voltage of this type, with non-
           linear performance, time dependent performance, of the
           cracking phenomena?
                       That latter part would come out at 3.10,
           and how are you going to from a management point of
           view compelled in this information in 3.8?
                       MR. MUSCARA:  From 3.10 and also from the
           inspection work.  My belief truly is that the voltage
           does not track crack size or crack code.  The linear
           literature is not with crack code, but with voltage
           code, which is meaningless.
                       So we happen to have a linear correlation. 
           We didn't try to make a scatter code really.  There is
           quite a bit of scatter, and so I don't know whether it
           is linear or what it is.  
                       But I think my point is that there should
           not be a correlation there with crack growth, but we
           will find a correlation with actual flaw sizes.
                       CHAIRMAN FORD:  So as we look down the
           time, and if what you say is correct, which I think it
           is, should we not be looking for another spectrum
           methodology which is more related to the physics?
                       MR. MUSCARA:  Yes, and I think in general
           that we are doing that in our program, and we have
           come up with some fairly good techniques for sizing
           flaws.  I presented the slides here and some reports
           are being published on this.
                       But we have come up with a very good
           technique for characterizing flaws, and particularly
           the flaw profile.  And from that we can get directly
           MSLB, and we have been able to predict the bursts of
           these tubes from the flaw profile and from the MSLB
                       EPRI is also working on different
           techniques for better characterization flaws, and the
           industry has moved towards other plugging criteria. 
           For example, at the tube support plate crack and the
           idea with dents.  This is an area where they are using
           the profile of the flaws.
                       They are getting away from voltage and
           using the actual profile to determine the burst
           pressures.  And I believe that is a direction to go
           into, and I think we are moving in that direction.
                       CHAIRMAN FORD:  And industry is responsive
           to these?
                       MR. MUSCARA:  Well, that is what industry
           is proposing, and utilities have come in with an
           ultimate criterion.
                       CHAIRMAN FORD:  Now what sort of time
           scale are we talking about for this more physically
           realistic inspection?
                       MR. MUSCARA:  Well, I think the
           characterization methods that we have now -- in fact,
           EPRI is a member of our IC program, international
           cooperation.  And they are aware of this process that
           we have developed for sizing flaws, and we are
           exchanging information, even to the point where we are
           going to turn over the algorithms.
                       CHAIRMAN FORD:  Are we talking about six
           months, a year?
                       MR. MUSCARA:  Again, right how this is a
           laboratory tool, and so in order to develop for the
           industry more work needs to be done to make it more
           user friendly.
                       And once it is in the hands of someone who
           wants to turn it into a field system, we are talking
           over a year or so.  But again besides their own work,
           there are other things that are coming up.  For
           example, this probe for doing better detection and
           probably better characterization of flaws.  
                       We are evaluating that, and that is
           something that is almost industry ready.  They have
           done a lot of work getting data from plants, and we
           are also incorporating them into our round robin
           exercises.  So we are evaluating that advance in
                       So technology is advancing, and I think to
           the point where we can start making use of the actual
           parameters of the flaw.  They should be profiled and
           length in depth, and then we can more accurately
           predict failure.
                       CHAIRMAN FORD:  I have one more technical
           question, and then we should discuss the ACRS type
           actions that we have to take.  On this one here, Joe,
           how do you take into account that we just don't know
           what is a good heat and what is a bad heat?
                       MR. MUSCARA:  That's true, but what we
           will probably do is catch bad heats, and work on the
           bad heats so that at least we will be conservative on
           what we find.  If we get a good heat, we will be
           testing forever and get no data.
                       CHAIRMAN FORD:  Yes, I understand that,
           and so your strategy on this is that we will go for
           the worst case scenario and just happens to have by
           chance some good heats?
                       MR. MUSCARA:  Frankly, I have not thought
           too much about doing heat variability in this work. 
           We will probably wind up doing several heats, but
           probably not a tremendous amount of heats.
                       And again the idea generally would be to
           find some susceptible heats, where we can do our work
           to evaluate different parameters on cracking.
                       CHAIRMAN FORD:  Okay.  Joe, thanks very
                       MR. MUSCARA:  So I guess now we will have
           the discussion on thermal hydraulics.
                       MR. SULLIVAN:  This is Ted Sullivan from
           the staff.  I would like to make one additional
           comment.  I think you started to touch on it when Joe
           was mentioning that this is a laboratory tool, and it
           is being made available to the industry.
                       But in terms of making a transition to
           applying that to ODSCC as a substitute for the
           voltage, first of all, you have got to get industry --
           I don't know who the you is, but industry has to be
           interested in basically making another proposal to the
           staff, and developing it to the point where it is a
           suitable substitute for the staff.  
                       And it has to happen -- if something like
           that were going to happen one of two ways, either the
           industry has to take it up and make a proposal in the
           room, or the staff would have to make a safety case
           that this sort of thing needs to be done.
                       And I don't think it is our view that it
           would be easy to make any sort of safety case, but
           that sort of transition needs to be conducted.
                       CHAIRMAN FORD:  Okay.  
                       MR. TINKLER:  Joe described for you some
           of the work being done by the Division of Engineering
           and Technology in the Office of Research.  I am going
           to summarize the work that is being done in the
           Division of Systems Analysis Regulatory Effectiveness
           in the Office of Research that primarily addresses the
           issues related to severe accident and design basis
           thermal-hydraulic conditions that create at least in
           part some of the loading conditions on the steam
           generator tube.
                       Be advised that all three divisions in the
           Office of Research actually are contributing to this
           initiative.  The Division of Risk Analysis and
           Applications is also heavily involved with NRR in
           integrating this analysis into our understanding of
           risk that are posed by steam generator tubes, both
           from the standpoint of initiating events on the design
           basis, as well as the risk from severe accidents.
                       Oh, and I am Charlie Tinkler, and I will
           be followed by Steve Bajorek, who will talk to you
           about our current thinking on the thermal hydraulics
           questions related to support and steam generator tube
                       Chris Boyd will also describe in more
           detail some recent analysis that he has completed on
           the staff to address the details of mixing in the
           steam generator and the steam generator tube --
                       CHAIRMAN FORD:  If I could just give you
           some guidance.  WE have another meeting beginning at
           one o'clock, and I guess the members would really like
           some lunch.  So if we can try and finish the whole
           thing by say, 20 by 12:00 at the latest, and bearing
           in mind that the information that we want to get a
           feeling for right now is whether the recommendation in
           NUREG 17-40 are being incorporated into this joint
                       MR. TINKLER:  Okay.  This is a list of the
           major recommendations of the ACRS Ad Hoc Subcommittee
           on the DPO.  They are going to be addressed in this
           presentation and that are covered by the work in our
                       We want to develop a better understanding
           of the behavior of the steam generator tubes under
           severe accident conditions specifically addressed by
           Steam Generator Task 3.4.
                       The evaluation of the -- and ACRS also
           recognizes that we evaluate the potential for
           progressions of damage to steam generator tubes during
           the rapid depressurization caused by a main steam line
           rupture.  That is the more traditional thermal-
           hydraulic issue, and that is specifically addressed in
           the action plan under Item 3.1.
                       To address the severe accident response of
           steam generator tubes, and general hydraulic boundary
           conditions in the reactor coolant system, and
           corresponding component behavior in the steam
           generator tubes, we have four basic parts to this
                       We have the system level code analysis,
           and the system using SCDAP/RELAP.  That is where we
           model the core, the RCS, the steam generator tubes,
           and all the other related components.
                       We are relying in part now on
           computational fluid dynamics code analysis and
           modeling, principally the FLUENT code, to model the
           single phase natural circulation and mixing in the
           steam generator tube bundle. 
                       It gives us a much better portrayal of the
           spacial dependencies and resolutions of temperatures
           within the system.  We are assessing again the 1/7th
           scale test data.  
                       These are the tests that were sponsored
           originally by EPRI in the 1980s, and later co-
           sponsored with the NRC as a mock-up of a steam
           generator -- of two steam generators and a reactor
                       The tests were designed and conducted
           primarily by Westinghouse personnel, and so
           occasionally you will hear them referred to as the
           Westinghouse 1/7th scale test.
                       We are also contemplating conducting some
           new experiments to investigate conditions that weren't
           addressed in those original 1/7th scale tests that
           have been raised in the DPO and raised by the ACRS,
           and I will talk about those briefly.  
                       Under 3.4, we have a multitude of subtasks
           that address a lot of the technical issues related to
           severe accidents.  These are some of those technical
           issues.  Some of these have their own separate
           subtasks in the action plan.
                       Plant design differences.  We have done
           the bulks of our calculations for the SERE (phonetic)
           design, which was the original basis for our tube
           integrity analysis for NRR.  
                       We started looking at -- and we have done
           calculations for other plants, and we are now focusing
           our attention on the Zion-like geometry, and that has
           a number of advantages.  
                       It is representative of a bigger group of
           plants, and it also allows for a little better
           comparison with some of the industry analysis, because
           the industry analysis more often is done for a Zion-
           like geometry.
                       And we have plant sequence variations, and
           we typically focus on station blackout type sequences,
           where one steam generator is also depressurized.  The
           steam generators have all boil dried, and the core has
           become uncovered, and now we have super-heated steam
           circulating through the loops.
                       Now we have a counter-current flow that we
           are primarily concerned about because for most of our
           calculations we predict the loop seal for the red
           coolant pumps is filled.
                       So we get counter-current flow out through
           the hot leg, and through the steam generator, and to
           one-third to one-half of the steam generator tubes,
           and returning through the remaining portion of the
           tube bundle, and back along the bottom of the hot leg
           to the reactor vessel.
                       This task is to look at variations on that
           sequence, and to look at the effects of reactor
           coolant pump seal leaking, and to look at leakage from
           PRVs or safety valves to see if there are variations
           on the sequence that pose some unique challenge.
                       In response to past ACRS comments, we are
           conducting a more rigorous uncertainty analysis to
           look at the influence of mixing parameters and other
           phenomenological issues in this calculation as part of
           the system analysis.
                       The ACRS raised in its ad hoc subcommittee
           report, and we recognize the importance of loop seal
           clearing in this analysis.  The effect of clearing the
           loop seals is to have unit-directional flow through
           the steam generator tube bundle,and not get the
           benefit of return mixing through the coolant portion
           of that flow.  
                       So it typically predicts higher
           temperatures.  It is normally associated with slightly
           depressurized sequences, and so we looking at those
           two effects combined.  The effect of tube leakage on
           inlet plenum mixing --
                       DR. POWERS:  Are you going to be able to
           resolve the issue of loop seal clearing just with
                       MR. TINKLER:  We think so.  We know that
           we have to present more analyses and our rationale to
           the committee on this matter, but we believe that is
           the case, and we understand the comments that have
           been raised, and we understand the concerns about
           small delta-P clearing loop seals.  
                       We understand that, and we have work to do
           on that, but right now we expect to address that
           analytically.  The effect of tube leakage on other
           plenum orientation, and this is the notion that if you 
           have tube leakage up in the bundle that it will
           disrupt the mixing in the inlet plenum that was
           observed in the 1/7th scale test.
                       So you won't get quite as an efficient
           mixing and you get perhaps channel flow or tunnel flow
           up through the inlet plenum, and that can create a
           locally hotter plenum.
                       And hot leg/inlet plenum orientation.  The
           1/7th scale test looked at a proto-typic Westinghouse
           steam generator, where the hot lay comes in low on the
           inlet plenum.  The CE designs have a hot leg
           orientation that comes in a little higher on the inlet
                       And so it is a little closer to the tube
           sheet, and so the argument there is that the mixing
           path lends a shorter -- you might not get effective
           mixing in the inlet plenum and the tubes will be
           exposed to higher temperatures.
                       These are areas that we expect -- that are
           well-suited to CFD calculation, but they also would
           benefit from additional testing, and we are
           considering that.
                       The things that we have to be mindful of
           are the scaling issues associated with these kinds of
           tests, and the need to run them with a denser fluid,
           like SF6, and that poses a problem in some facilities.
                       There are a host of instrumentation
           issues, as well as costs.  Tube to tube variations. 
           When we do air calculations with control volume codes,
           we have relative coarse nodalization of these volumes.
           And inlet plenum is basically three control volumes.
                       Now, that's okay if you are using the
           empirical models developed by the experimenters, but
           if you want to hope to model the response of tubes or
           clusters of tubes in a 3,000 tube bundle, you need
           finer resolution.  
                       So we were looking to see if the analysis,
           as well as perhaps additional testing, to get more
           insights on that.  And fissure pipe deposition.  This
           relates to the risk impacts.  
                       The ACRS has commented in the past that we
           might not be taking full credit for those severe
           accidents where tube leakage or tube rupture occurs. 
           The fact that that tube bundle and the upper internals
           of steam generator will serve as a mechanism for
           deposition of aerosols.  These radioactive aerosols
           wouldn't be transported off-site
                       Now, there is testing that is planned in
           the Artis facility in Switzerland, the Paul Shearer
           Institute is conducting tests where they have a mock-
           up of steam generator tube bundle, and they are
           looking at the deposition of aerosols under their
           severe accident conditions or a range of conditions.
                       Here is 3.4, the near items.  We are doing
           system level analysis to look at sequence variations
           to look at the effect of reactor coolant pump seal
           leakage,and to look at issues associated with safety
           valve leakage, and to look at the effect of tube
           bundle leakage.
                       And we are looking at the effect of tube
           bundle leakage from a systems standpoint, and not a
           local CFD level.  We are also looking at alternate
           steam generator depressurization.  Typically, we do
           these calculations with the pressurizer loop steam
           generator being the one that is blown down and
                       And we have calculations being done
           looking at the other three loops to see if it makes a
           difference, and we are also looking to see to the
           extent that we clear loop seals in some of these
                       We have done the calculations where we are
           halfway between a draft report and a final report, and
           so we are not quite ready to talk to you about these
           results, but we will in upcoming subcommittee open
                       Our next task is to reevaluate some of the
           SCDAP/RELAP modeling and simplifications of
           assumptions, things like radiation heat transfer and
           the hot leg; and some of the loop seal clearing issues
           we hope to address in this.  
                       It might also give us a vehicle for
           looking at some of the comparative items between
           industry calculations and our calculations.  
                       Subtask 3.4e.1, benchmark of the CFD
           methods.  That is the FLUENT against the 1/7th test
           data, and this work was just recently completed on
           schedule in August. Chris Boyd will talk to you about
           it in more detail.    
                       Lastly, design basis and thermal
           hydraulics.  This was to address the issues in the DPO
           that were raised by the depressurization by blowing
           off a relief valve, or a main steam line break.  That
           is just a cryptic summary of the kinds of loads.
                       Steve Bajorek will just describe to you a
           little more of our thinking at this point on how we
           are going to tackle that issue, and he is next.
                       MR. BAJOREK:  Good morning, or good
           afternoon, I guess now.  My name is Steve Bajorek, and
           I am also a member of the SMSA branch, and relatively
           new to that branch.  
                       What I am going to talk about are some of
           the issues pertaining to generating the hydraulic
           loads that we are going to need to evaluate the blow
           down forces on the steam generator.  The work that we
           are doing initiates from two different contentions. 
                       I have listed them both here, and both
           arise due to the uncertainty in what are the hydraulic
           loads and forces that result across the tube sheet,
           and across the tubes during the break, and the rupture
           of the main steam line break, or potentially another
           relatively large pipe connected to the secondary side
           of the system.
                       By way of background, I think it is useful
           to think of the high pressure depressurization of a
           system into two overall segments.  We can think of the
           first phase; that while this fluid is primarily
           subcooled, and while the depressurization waves
           propagate through the system at a sonic velocity,and
           then another phase of that depressurization once those
           waves have dissipated, and the system depressurizes
           primarily dependent upon the break flow and the size
           of the break.
                       This is an issue that is actually of
           fairly well-studied in the initial design of a reactor
           system from the point of view of the primary; whether
           you have rod drop or not, or whether you will have
           grid crushing within the core, is dependent on your
           design and how you evaluate the breaks to the primary
           system to take a look and track the depressurization
           waves as they move through the loops, and through the
           core, and potentially move the core barrel from one
           side of the downcomer to the other.
                       A good analysis of that type of event
           tracks the waves at sonic velocity, and incorporates
           a fluid structure interaction between the core barrel,
           which is the primary component of interest in that
           type of an analysis, and generates the delta-Ps from
           one side of the downcomer to the other side that we
           give to the structural analysis so that they can
           perform a structural analysis and tell us whether the
           rods are dropped, or whether the core barrel deflects.
                       We have a similar situation now that we
           need to address on the secondary side.  Now, I think
           the reason why that has not received as much attention
           as the hydraulic forces that develop on the primary
           side has to do with the rate at which those waves move
           through the primary or through the various systems.
                       For the primary system Tcold -- and C
           stands here for the sonic velocity, and this is at
           about 550 degrees fahrenheit, at typical Tcold at
           pressure, moves through the system at a little bit
           greater than 1,000 meters per second.
                       If you think of the primary system full of
           sub-cooled liquid early in the transient, this wave is
           certainly capable of moving through the loops in the
           core on the order of a couple of dozen times, and
           interacting with waves which move throughout other
           parts of the primary system, generating fairly complex
           loading across the core barrel or the steam generator
           divider plate, and other things that need to be looked
                       And causing some of those components to
           move.  And we need to start thinking about what that
           type of analysis or evaluation does now over on the
           second side.  But it is important to keep in mind that
           the most important physical parameter which determines
           the velocity of that wave is its density.
                       And in the primary system, typical
           conditions are that we are seeing velocities a little
           bit later than a thousand meters per second.  On the
           secondary side, the velocity that we might find in
           saturated liquid at about 900 psi, just a little bit
           less than what we would see on the primary system, the
           difference being the difference in the density.
                       However, in the vapor space, that velocity
           drops significantly to roughly half of its value.  Now
           when you do a thermal-hydraulic evaluation of the
           primary system, that analysis to take a look at the
           interaction of the waves goes for on the order of
           milliseconds, because what happens is that as soon as
           we start to form some voids within the system, those
           waves are dissipated very rapidly.
                       And the interaction of the waves becomes 
           a no, never mind, in the analysis.  It is something
           that will probably help out the structural evaluation
           here on the steam generators secondary side.  That is
           not to say that those loads are going to necessarily 
           be small, because there will still be a fairly
           significant shock to the tube sheet and resulting
                       Now, because the steam generator either
           has significant voids through the bundle region at a
           steady state, or has an interface at no load
           condition, the most significant pressure wave that is
           going to cause motion of the tube sheet and transient
           stresses on other components within the steam
           generator is going to be this initial wave that moves
           through the steam generator.
                       We won't have much in the way of
           reflection or interaction, with the exception of the
           fact that we have more voids on the interior of the
           steam generator, and sub-cooled fluid in the
           downcomer, and so conceivably we could see a wave
           moving down the steam generator downcomer, and
           reaching that portion of the tube sheet earlier than
           we would in the interior of the bundle.
                       So our initial approach -- and we have got
           to admit that we are in the very initial stages of
           developing a plan of attack at this point -- is to try
           to develop relatively conservative hydraulic loads
           that we can give to delta-P(t) for them to apply to
           their finite element model, and to determine the
           bending stresses and other stresses that they get out
           of that type of an analysis.
                       Our approach is first going to try to use
           what I will call glorified hand calculations to
           determine, one, what is the initial time at which that
           depressurization wave reaches the tube sheet and
           various parts of the steam generator base, and augment
           that with track 3-D calculations to look at the later
           stages of the blow down of the steam generator
           secondary side.
                       Now, during that phase of the accident
           something like a TRAC or RELAP should give us a
           reasonable depressurization.  I would not expect it to
           do a credible job during this very initial part, where
           you have to TRAC the sonic wave and the interactions
           that it has with the various components.
                       That's why our initial plans are to try to
           get something that is conservative with the hand
           calculation, and augment it with the TRAC-M
           calculations, and give that to the finite element.
                       And if you can come back and tell us
           whether we have lots of margin, or there is a little
           bit of margin on that.  If the answer comes back that
           we have just a very small amount of margin, the next
           part of our evaluation would be to replace the hand
           calculation with something better.  
                       That would not necessarily be TRAC-M.  I
           think we have to look at that closer and make up our 
           minds whether it could or could not do that.  The
           tools that might be available to us to analyze this
           are the things like the multiplex code that is used by
           Westinghouse to evaluate the subcool blow down on the
           primary side.
                       The staff a number of years ago to my
           recollection did have access to a code, and I think it
           might have been called SLAM, to take a look at that
           type of a scenario on the primary side.
                       That might be a better starting point than
           trying to force the TRAC-M to give us that type of
           sonic wave depressurization.  But we would go along
           that path if we were to find that we wouldn't have
           enough margin and structural analysis, and then make
           a decision on what would be a more appropriate tool.
                       If necessary, then look at some
           experimental testing to try to augment our code
           validation at that point.  At that point, if we had
           such limited margin, that might also be a good time to
           go back to the vendors and use perhaps their tools to
           try to evaluate the same type.
                       CHAIRMAN FORD:  Thanks very much indeed.
                       MR. TINKLER:  Thank you.
                       MR. BAJOREK:  I have more slides than
           eight minutes, but I am just going to go through them
           quickly.  Charlie covered a lot.  This Charlie
           described, and I am just going to show this as the
           thermal-hydraulics of interest that we are going to
           focus on in this small subtask that I am carrying on.
                       I want to make this point before I start,
           and that is that the SCDAP/RELAP code is what we are
           relying on to get our thermal-hydraulic results to
           pass on to the materials people.
                       The tube temperature predictions that the
           tubes are subjected to come out of that code, and they
           are influenced directly by mixing parameters.  So I am
           making the point that we are going to use SCDAP/RELAP
           and that gives temperatures that are affected by
           mixing parameters, and these mixing parameters are
           fixed in the code, and they are determined from the
           1/7th scale testing principally and other tests if
                       So these mixing parameters are what I am
           going to focus on.  The advantages of CFD.  I just
           give this slide to show an example that we are about
           four orders of magnitude more cells, on the order of
           hundreds of thousands, to a million, versus 10 to a
                       Less expensive experiments as you pointed
           out, and we are going to have a direct resolution of
           mixing.  We are not tuning the code.  We are using the
           most appropriate turbulence models from an academic
           point of view, and then just letting the code go.
                       So again no fixed mixing parameters.  We
           are extending the data with CDF, or we will to full-
           scale, full-pressure, full-temperature steam, and then
           we can look at this inlet geometry effects and tube
           leakage effects that Charlie mentioned.
                       DR. KRESS:  Do we have options in the
           fluid code or for what turbulence parameter, different
           options for turbulence parameters?
                       MR. BOYD:  We have different turbulence
           models, and several to choose from, and then within a
           turbulence model, you can then tune that to the data. 
           We are not doing that type of tuning.  We are kind of
           using industry standard coefficients.
                       We don't really have data to do that kind
           of tuning, and we are not tuning to get the answer we
           have from the 1/7th scale test.  We are just letting
           it fly.
                       DR. KRESS:  Are you choosing one option,
           or are you --
                       MR. BOYD:  We chose several options just
           to look at the differences.  In the end, they did not 
           make a lot of difference.  The one that we chose was
           the second order of Reynolds Stress Turbulence Model,
           which is for this type of flow, it is -- I guess on
           paper it would be the appropriate model, as opposed to
           a two equation K-epsilon model. 
                       So in this type of flow field, I guess we
           chose the academically appropriate, and in all the
           selections that we made there wasn't a large
           difference.  It did not affect these types of
                       This is a quick slide to show the CFD
           approach versus a lumped parameter.  The top picture
           shows the hot leg, and I guess that is not really
           showing up, but what you see is a full counter-current
           flow profile, with velocity vectors and temperature
                       And on the right in a lump parameter code,
           SCDAP-RELAP, there is just two pipes with a single
           temperature, and you have mass flow and temperature.
           In the inlet plenum, this is the SCDAP-RELAP
           nodalization in the middle on the right, and you will
           see the three mixing volumes.
                       Flow comes in and based on the mixing
           fraction, it either goes to a mixing volume, or it
           passes up through to the tubes, to again a fixed
           number of tubes.
                       With the CFD predictions, we are going to
           calculate the mixing implicitly with the code, and
           then as far as the tubes go, this is something that we
           will add a benefit to our predictions.
                       In the SCDAP-RELAP predictions, you are
           going to get one temperature and a number of tubes and
           up-flow that is predetermined.  And in the CFD
           predictions, we will get the number of tubes
           calculated implicitly, and then we will also get tube
           to tube variations.
                       So we will know not just the average
           temperature going into the tubes, but what the peak
           average ratio is.
                       DR. KRESS:  On your counter-current flow,
           what do you do at the reactor end?
                       MR. BOYD:  At the reactor end, initially
           I put the core in there, and I just had a heat source
           and let it go, and it picked up that counter-current
           flow.  I had a lot of uncertainty in my core model
                       I was using a lot of core options, and I
           cut that off, and at this point I just put on the end
           of the hot leg a mass flow in.
                       DR. KRESS:  You just put it at one end?
                       MR. BOYD:  That's right.
                       DR. KRESS:  And that stuff going out just
                       MR. BOYD:  It is called a fixed pressure
           boundary there.
                       DR. KRESS:  A fixed pressure boundary?
                       MR. BOYD:  Yes.  And I did a lot of
           variations with different velocity profiles, and all
           sorts of things to match the mass flow given in the
           test results.
                       DR. KRESS:  And you had to specify the
           profile specification?
                       MR. BOYD:  That's right, and I found that
           my profile specification wasn't all that significant. 
           By the time that it got to the steam generator end of
           the hot leg, it had dissipated anything that I had put
                       So, CFD is going to provide an improved
           understanding of the 1/7th scale data.  We have got
           these tests, and obviously what went on in the tests
           was fine, but we have a limited view of the tests from
           the limited instrumentation.
                       So we can fill in some of the gaps with
           CFD, and then we can extend to full-scale.  One of the
           big questions is does scale affect the mixing
           parameters, and that is something that we are looking
           to address right now.
                 At that point, when we have gone to full-scale,
           we have answered that question among others, and then
           we can start looking at the effect of tube leakage and
           how that affects these inlet plenum flows, and mixing
           parameters, and the effect of the inlet geometry
           variations, like the CE plants with the hot leg
           entrance closer to the tube sheet.
                       And again we will get implicitly out of
           this tube to tube variations that then would give some
           understanding of what the hottest tube really is.
                       The schedule.  Validate the technique by
           looking at the 1/7th scale.  That is our best
           available data set.  That has been done and in general
           the answer is that the code picks up all the relevant
           physics and does a pretty good job.
                       At this point, we are sensitivity studies,
           and extending the predictions to full-scale, using a
           kind of best estimate conditions out of a SCDAP-RELAP
                       Again, what is the effect of scale, and
           then we are going to complete additional studies on
           tube leaking and inlet geometry variations, as well as
           other sensitivity studies.  
                       And just to give a quick view.  This is
           the mesh that we that was used for the 1/7th scale. 
           It's a symmetry model, half of the hot leg in the
           plenum and tubes.  All the tubes in that test, 216,
           were modeled individually.
                       We won't do that at full-scale, and we
           will come up with a model for the tubes.  But that
           gives an idea of the resolution.  There are several
           hundred-thousand cells just in the inlet plenum alone.
                       There are some qualitative results.  This
           is the first thing that hits you when you -- well, all
           of the qualitative flows predictions are correct.  In
           other words, a sloping interface in the hot leg, and
           a plume that rises and dissipates fairly quickly into
           the inlet plenum, and about a third to a half of the
           tubes in up-flow.
                       The temperature of the tubes reaching the
           given values in the test, and by the time it reached
           the top of the tubes.  All these kinds of qualitative
           features were matched by the CFD predictions.  This is
           quantitative data, but I'm just talking qualitatively
                       When we go to the actual mixing parameters
           of interest, this table shows some of the results. 
           These are the tests of most interest.  In general,
           what you saw was about a 10 percent deviation.  
                       If you look at the Westinghouse data
           carefully, you will determine that the uncertainty in
           that data is around 10 percent or more.  The one big
           variation was the number of hot tubes.  
                       We were 23 tubes over, which is about 10
           percent of the tube sheet, and we are currently doing
           some sensitivity studies to determine what boundary
           conditions or condition in our model might affect that
           to see if we may have a problem.
                       And all the hot average temperatures, and
           mass flows, and things like that, were all pretty
           close, and in this particular run we had a 15 percent
           difference in the recirculation ratio, which again I
           believe is in the uncertainty of the data.  
                       So as a quick look, what I get out of this
           is that the code can do this type of analysis, and
           that the results are pretty close.  This is the tube
           sheet flow, and this is the number that I mentioned,
           10 percent over-predicted.  
                       The dark region on the tube is from the
           data.  There is two lines there because the data had
           an uncertainty, and not every tube was instrumented.
           So somewhere in that range is where the boundary
           between where up-flow and down-flow in the tube sheet
                       And then the outer dashed line represents
           the FLUENT predictions.  On the right, I give the peak
           temperatures.  The peak thermal-couple in the data
           read 59 degrees celsius in this case.  These again are
           cold tests done with SF6.
                       The maximum predicted value from FLUENT
           was 61.5 degrees, and that was on the center line. 
           The data did not have any center line thermal-couples. 
           If you look off-center line, it would be more
           consistent with the data.  I had a max prediction of
           58.5, which was pretty close to the measured value.
                       So as a summary, the CFD predictions are
           generally within 10 percent of its 1/7th scale data,
           and that is generally within the experimental
           uncertainty.  There was a fair amount of uncertainty. 
           There was no mass flows directly measured in the
                       They had to infer that from energy
           balances, and some of these energy balances were
           inferred from small delta-Ts.  So this added to the
                       The phenomena observed during the tests
           were all predicted by the CFD code in a qualitative
           sense, and so the general flow features are there, and
           work on full-scale predictions is proceeding now, and
           I think we have a high degree of confidence in our
           technique, and so when we go to full pressure, full
           temperature steam, there is not going to be as much
                       So this benchmarking exercise has been
           very valuable, and I think this is just a restatement
           of that.  The CFE technique has been demonstrated to
           be applicable, especially for predicting these mixing
           parameters, which are kind of average values.
                       And this work provides this high degree of
           confidence, and we are going to go to full-scale
           analysis, and at full-scale, then we will spend our
           time doing the tube leakage and geometry variations,
           and our sensitivity studies.  I am just a few minutes
                       CHAIRMAN FORD:  Thank you very much
           indeed.  I would ask for any comments from the members
           here.  We have on our schedule for the next ACRS
           meeting next week -- we are charged with a letter
           relating to the DPO.
                       And essentially hopefully saying that the
           recommendations that were in 17.40 are being followed
           in the new NRR research plan.  That is hopefully what
           the letter would say.  Is that correct?
                       DR. KRESS:  The intent is to address that,
                       CHAIRMAN FORD:  Okay.  Could we have some
           comments to help the staff and research as to how they
           would appropriate their time for the 30 minute
           presentation that they would have in that one hour?
                       DR. KRESS:  I would like the approach
           where they are listing what the ad hoc committees'
           recommendations were, and then to say how we are
           addressing them in the plan.  That would work very
           well.  I certainly would want to have the full
           committee see this CFD stuff, and that addresses some
           of the --
                       DR. SHACK:  But we will never get through
           it in 8 minutes.
                       DR. KRESS:  But that addresses some of the
           real issues that the staff may have.
                       DR. POWERS:  The plans are sufficiently in
           the works, and I don't see why the subcommittee
           chairman can't just summarize it.
                       DR. KRESS:  I think that is probably right
                       DR. POWERS:  Well, all you are going to do
           is say the staff has plans to address this issue, this
           issue, this issue, and this issue.
                       DR. KRESS:  And they look like good plans.
                       DR. POWERS:  And in 9 out of 10 cases,
           they have great plans, and in one case, I haven't got
           a clue.
                       CHAIRMAN FORD:  The one question I have
           got, Dana, because I know nothing at all about it, is
           the thermal-hydraulics codes.  Are you all feeling
           that these are the right approaches?
                       DR. POWERS:  The one thing I know is that
           if you put two thermal-hydraulicists in a room, the
           one thing they cannot arrive at is a conclusion.  What
           I would say is why don't we have the subcommittee
           chairman draft a summary, and put it up for the rest
           of the committee, and say we are addressing the issues
           that have been raised, because there is no more
           content than really that that they are addressing.
                       I mean, most of these things are in the
           works, and they are working on it, and then allow the
           speakers on this CFD stuff and the counter-current
           flow, because that implies so many things other than
           the steam generator tube --
                       DR. KRESS:  And Dr. Wallis hasn't heard
                       DR. POWERS:  Well, more in the context of
           here is some research that is going on now, and here
           is where we stand, and more as an update of general
           interest than just a DPO issue.  
                       CHAIRMAN FORD:  And that you think will be
           enough sufficient information to allow George to sign
           his name to a letter saying essentially that the
           recommendations from the ad hoc committee, and
           therefore the ACRS, are being followed?
                       DR. POWERS:  Are being addressed, yes. 
           They are taking them into account.  That is what we
           were asked, and they know them better than I do.
                       CHAIRMAN FORD:  So the answer could be
                       DR. POWERS:  Yes.
                       CHAIRMAN FORD:  Just one word.
                       DR. POWERS:  Yes.  
                       CHAIRMAN FORD:  So you are asking me to
           stand up in front of the ACRS committee and summarize
           what we have heard today, and then for general
           information to have the thermal-hydraulic guys
           specifically get up and talk?
                       DR. KRESS:  As an alternative, if that is
           uncomfortable to you, you could ask one of these guys
           to summarize.
                       DR. DUDLEY:  Just from a public holding,
           and a presentation in a public meeting, at a full
           committee meeting to write a letter from, I think it
           would be more appropriate if the staff presented a
           summary, and then it would also save the subcommittee
           chairman the effort of pulling that together.
                       DR. POWERS:  But a summary presentation.
                       DR. KRESS:  Yes, a summary presentation.
                       DR. POWERS:  I think the committee as a
           whole is going to be very interested in what they are
           doing with this counter-current flow issue because it
           has been around since the dawn of time, and there has
           been lots of concern about it for a variety of things.
           And let that talk go on at length.
                       DR. SIEBER:  And also the tube sheet --
                       DR. POWERS:  Well, that one is
           interesting, but I think that we are fixing to work on
           this.  I think we can hold that one off until they
           have got some more results.
                       CHAIRMAN FORD:  Could I suggest the
           following?  Who is going to stand up and say I am the
           project leader for this and this is a problem, and
           where you are going, and this action plan, the joint
           NRR/research plan, is feeding into that overall
                       Just one draft, and one slide saying this
           is where we are going in general, and I am quite ready
           to stand up and say this is in line to go alone with
           your line.  Here is the action plan, and here are the
           actions in the NRR/research program, and these are the
           ones that we specifically recommended, et cetera. 
           Does that sound fair?
                       DR. POWERS:  Yes.
                       CHAIRMAN FORD:  Is that clear? 
                       DR. POWERS:  All right.
                       CHAIRMAN FORD:  All right.  We are
                       (Whereupon, at 12:30 p.m., the meeting was

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