Thermal-Hydraulic Phenomena - September 27, 2001

                  Official Transcript of Proceedings


Title:                    Advisory Committee on Reactor Safeguards
                               Thermal-Hydraulic Phenomena Subcommittee
                               Duane Arnold Energy Center Power Uprate

Docket Number:  (not applicable)

Location:                 Rockville, Maryland

Date:                     Thursday, September 27, 2001

Work Order No.: NRC-033                             Pages 178-327

                   NEAL R. GROSS AND CO., INC.
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                          (202) 234-4433                         UNITED STATES OF AMERICA
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                            SEPTEMBER 27, 2001
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                            ROCKVILLE, MARYLAND
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                       The ACRS Thermal Phenomena Subcommittee 
           met at the Nuclear Regulatory Commission, Two White
           Flint North, Room T2B3, 11545 Rockville Pike, at 1:00
           p.m., Dr. Graham Wallis, Chairman,
                 DR. GRAHAM WALLIS, Chairman
                 DR. F. PETER FORD, Member
                 DR. THOMAS S. KRESS, Member
                 DR. DANA POWERS, ACRS Cognizant Member
                 DR. VIRGIL SCHROCK, ACRS Consultant
                       PAUL A. BOEHNERT, ACRS Staff Engineer
                        AGENDA ITEM                        PAGE
           Introduction and Open Questions  . . . . . . . . 181
           NRR Presentations. . . . . . . . . . . . . . . . 191
           Open Issues. . . . . . . . . . . . . . . . . . . 283
           Concluding Remarks of Subcommittee . . . . . . . 306
                                                    (1:00 p.m.)
                       CHAIRMAN WALLIS:  The meeting will come to
           order.  This is a continuation of yesterday's meeting
           of the ACRS Subcommittee on Thermal-Hydraulic
           Phenomena.  I am Graham Wallis, the Chairman of the
           Subcommittee, and I will immediately hand the meeting
           over to Dana Powers, who is the Cognizant Member for
           this meeting.
                       DR. POWERS:  Thank you, Professor Wallis. 
           We are going to go quickly through the staff's version
           of this application for a power uprate from Duane
           Arnold this morning.
                       And at the conclusion of the
           presentations, I am going to walk around the
           membership to discuss two things.  First, their
           reactions to what they have heard; and second of all,
           trying to develop some guidance both to the staff and
           to the applicant on what they should think about
           presenting to the full subcommittee in support of our
           subcommittee report.
                       To the extent that the members have
           thoughts as the presentation goes along, I hope that
           they will send me notes so that I can start assembling
           something of an agenda, and some idea of how long it
           will take.  
                       My opening feeling here is that right now
           the central issues that will be of interest to the
           full committee are the PRA results and the code audit
           results from the staff, but that is just my initial
           impression at this point.
                       I think we did have some open items left
           over from yesterday's presentation by the applicant,
           and I will ask Ron if he has anything that he would
           like to touch on just to fill us in.
                       MR. MCGEE:  Good morning.  This is Ron
           McGee of NMC.  Yesterday, there were a few questions
           that we looked up some material from yesterday.  The
           first was dealing with the scaling factors associated
           with our stress calculations, and with that, I will
           turn the discussion over to Al Roderick.
                       MR. RODERICK:  I am Al Roderick, with NMC,
           at the Duane Arnold Energy Center.  The question was
           where the 12-1/2 percent increase, the scaling factor
           came from for the main closure flange, even though it
           is a constant pressure power uprate.
                       I talked with the people that did the
           detailed work, and in addition to normal operation,
           they also look at all the transients that are applied,
           and then the most limiting one is used to determine
           the scaling factor.  
                       So, in fact the turbine trip transient
           event pre-EPU showed an 8 degree temperature change
           during that event, and the analysis after, or when we
           are considering EPU conditions, showed a 9 degree.
                       So that ratio, going from 8 degrees to 9
           degrees, is a 12-1/2 percent increase.  So we are
           talking about a very small number, and it was
           following the simple, straightforward, considerative
           methodology in calculating that ratio.
                       CHAIRMAN WALLIS:  Wait a minute.  I am
           concerned here because it is supported with 9.2
           degrees, and as I remember, your number went up to
           pretty close to the limit.  You went up from -- I have
           to look at the numbers.  
                       Well, from 68 to 77 and the limit was 80. 
           So I now have to worry, and if you are saying that one
           degree is worth this change, then was it 1.0 or 1.1,
           or 1.2 degrees.  What accuracy are we talking about
           here?  That is the cause of it.
                       MR. RODERICK:  This is a very conservative
           methodology that is being used to verify code
           compliance, and the conservative scaling factors were
           determined following their methodology looking at EPU
                       And the scaling factor was applied to the
           current calculated stress, and the EPU stress MEDCO
           allowables, and that satisfied the acceptance
           criteria.  So no further detailed work was needed.
                       CHAIRMAN WALLIS:  Well, you understand my
           point.  You are saying 8 went up to 9, and that's 12-
           1/2 percent, and one degree is 12-1/2 percent.  We are
           talking about 77,364, which is an accuracy of one part
           in about 77,000.
                       And I would have to worry that if your
           reason is that it went from 8 to 9, maybe it went from
           7.9 to 9.1, which would take you over the limit of
                       So I think we need to have something in
           writing that is more rigorous.  I'm sorry, but it just
           doesn't sound good enough, unless the committee wants
           to override me on that, but that is my opinion.  Dr.
           Ford is an expert on materials.
                       DR. FORD:  Well, that was my first
           reaction.  That is a source of the 12 percent.
                       MR. WU:  Good morning.  I will try to
           answer the questions.  You have to understand that I
           am the reviewer on these parts as a matter of fact.  
                       MR. BOEHNERT:  Can you identify yourself,
           please, sir.
                       MR. WU:  Okay.  My name is John Wu. 
           According to the methods, if we have some increase,
           like a transient in temperature or flow, or pressure
           transient, normally you do -- you know, you develop
           the factor, the scaling factor.
                       Then usually the scaling factor multiplies
           the -- and the -- actually, if you say the temperature
           increases by one degree, which means you increase
           probably only -- well, only thermal, and that
           increases by 12.5 -- and actually this choice
           including seismic and all other LOCA.
                       And now because of these conservative
           measures, you must multiply by the -- and the upper
           multiplication after you multiply by that is then
           allowable, and then we say, okay, we will not go any
                       So actually 12.5 is only -- you know,
           because of the scaling factor, is very conservative. 
           But it is the thermal stress -- that is only part of
                       CHAIRMAN WALLIS:  I think that must be
           right.  It can't be that the thermal stress is this
           entire 77,000 psi.
                       MR. WU:  No.
                       CHAIRMAN WALLIS:  So the thermal being 12-
           1/2 percent can't be the whole story.
                       MR. WU:  Right.
                       CHAIRMAN WALLIS:  Now, what we need is a
           solid written explanation.
                       MR. WU:  Probably they need -- it is
           detailed, but this is the way they do it.  They
           multiply whatever the change is, and the change is
           where you have the scaling factor, and you multiply it
           by the -- and you are including the thermal pressure
           and everything in there.
                       CHAIRMAN WALLIS:  So I think this could be
           resolved by a written communication of some sort.
                       MR. WU:  Yes.
                       CHAIRMAN WALLIS:  Thank you.
                       MR. WU:  And confirmation of it.
                       DR. POWERS:  Ron, did you have any other
           points that you wanted to make?
                       MR. MCGEE:  Not at this time.  Oh,
           concerning other questions left open from yesterday?
                       DR. POWERS:  That's right.
                       MR. MCGEE:  There was questions concerning
           H202 monitoring post-LOCA, and with that, I will turn
           the discussion over to Steve Huebsch.
                       MR. HUEBSCH:  The first thing is that
           there was a question -- oh, this is Steve Huebsch,
           NMC.  There was a question about the five percent
           limit, I believe that was in the write-up.
                       Do you want me to go through all of that,
           or did you want to specifically tailor the question to
                       CHAIRMAN WALLIS:  Well, the five percent
           -- maybe the staff can do it.  My comment simply was
           that in reading the SER the explanation seemed turgid. 
           I just wanted a clear explanation, and maybe the staff
           will give that to us today.
                       MR. HUEBSCH:  Well, I can go through that
           real quickly if that was the intent, and the five
           percent limit is out of the regulation for oxygen
           limit.  Duane Arnold is a Mark-I containment.  It is
           a nitrogen inerted containment.  
                       So as part of EPU, we looked at the
           hydrogen-oxygen generation rates, and predominantly
           because of the EPU, you saw that your increases were
           from two factors.  One was an increase in generation
           because of radiolyosis, and the second one had to do
           with the redesign of the fuel, the GE-14 fuel.
                       So those were the two main factors that
           changed the rate of generation.  Duane Arnold monitors
           oxygen content in order to keep the flammability
           limits, because with the nitrogen containment, the
           hydrogen needs an oxygen component to reach there.
                       So in looking at the analysis, we
           identified that because of these two methods that we
           would reach that 5 percent oxygen limit by about a day
           sooner than we did prior to EPU.  
                       So one of the things that we did was that
           we have a containment atmosphere dissolution system
           that we use to mitigate that concern, and the CAD
           system on site had the capacity to increase the
           quantity or the mass of nitrogen in the system to be
           able to maintain that oxygen limit below five percent
           for the duration of the seven days as required by the
                       So we increased the mass retention in that
           system in order to keep the oxygen limits below the
           five percent from roughly 2.3 days into the event to
           the 7 day mark.
                       The other issue with the oxygen --
           hydrogen-oxygen monitors that is in the write-up deals
           with the heat trace that we have installed.  Our heat
           trace lower limit is 200 degrees, and so the heat
           trace cycle is roughly between 200 and 215 degrees.
                       And from a conservative nature, we looked
           at that, and what we know is that our monitors are --
           they read conservatively high when the drywall or
           containment temperatures are above the heat trace
                       So what we have done is that in the
           submittal, we have identified that the containment
           hydrogen/oxygen monitors will not meet the
           requirements of Reg Guide 197, and the NUREG 0737 for
           the first period of time until drywall temperatures
           come down.
                       However, they will be operable.  They will
           be reading a little bit high.  But we will be able to
           use them for trending, and we will be able to monitor
                       Since we don't have any actions taken for
           roughly 2.3 days, we felt that a 24 hour change in the
           commitment prior ot meeting the requirements of the
           Reg Guide 197 accuracies was appropriate.
                       And as I said, we still have them, and we
           will be able to turn them on and we will be able to
           use them for monitoring and trending of the generation
           rates, such that the control room operators will be
           able to figure out when they are going to have to take
           appropriate mitigation steps.
                       CHAIRMAN WALLIS:  So they don't meet the
           requirements, but it is at a time when they are not
           needed.  Therefore, you made that argument, and does
           the staff accept that argument?  
                       MR. MCGEE:  Is anyone here from the
           containment systems branch?
                       MS. MOZAFARI:  Well, I just wanted to let
           you know --
                       DR. POWERS:  I don't think we are ready
           for you yet.
                       MS. MOZAFARI:  Well, I wanted you to know
           that the containment systems, if you are going to ask
           about the containment systems and analysis, the staff
           is on a holiday today.
                       CHAIRMAN WALLIS:  That's why they invited
           us down here, right?
                       MS. MOZAFARI:  The containment systems
           staff, it is a religious holiday, and they were not
           able to make it today.
                       CHAIRMAN WALLIS:  I see.  Okay.
                       MS. MOZAFARI:  We talked to Paul about he
           possibility of either tomorrow morning or presenting
           actually in the full committee the results of the
           analysis.  So I just wanted to let you know that.  I
           am Brenda Mozafari, the project manager for the
           licensing for Duane Arnold.
                       MR. BROWNING:  I think we understand what
           Duane Arnold did.  We need to understand how the staff
           looked at that.
                       CHAIRMAN WALLIS:  And why it is
           acceptable, yes.
                       DR. POWERS:  That's right.  Ron, do you
           have any other points?
                       MR. MCGEE:  Not at this time.  Thank you.
                       DR. POWERS:  Okay.  Thank you, Ron.  Okay. 
           We will now turn to the presentations by the staff,
           and Brenda, you are going to provide us an
           introduction on this?
                       MS. MOZAFARI:  Right.  As I said, by way
           of introduction, my name is Brenda Mozafari, and I am
           the Duane Arnold licensing project manager for NRR. 
           And you did receive the draft safety evaluation --
                       MR. BOEHNERT:  Excuse me, Brenda, but you
           need to speak in the mike.  
                       MS. MOZAFARI:  You did receive the draft
           safety evaluation and I guess I want to emphasize that
           it was draft.  We felt that it would not have been a
           good thing to postpone the ACRS again for purposes of
           tieing it up in a nicer packaging once we because
           pretty convinced that our evaluation was complete,
           with a few things still left to tie up a the end.
                       I think that we want to present here today
           the basis for the draft safety evaluation, recognizing
           that there were formatting and wording errors, and
           matters left to resolve.  But we felt that they were
           at least close to closure, and the staff is going to
           present their evaluation.
                       The containment analysis portion, as I
           said, is going to be addressed later, but I believe
           that George Hubbard was going to be here today if
           there were any general questions.
                       And I want to give you the order of
           presentation.  Ralph Caruso, who is the section chief
           of reactor systems, is going to speak first on the
           reactive core fuel performance area.
                       Then John Wu will discuss material
           degradation issues, and he will be supported by
           members of the materials engineering staff who are
           here to support him.
                       Then we will do the PRA review and ATWS
           response, and Donald Harrison is here to present that,
           and Dick Eckenrode is going to provide additional
           information on the human factors portion.
                       We do have two open issues at the time of
           the draft safety evaluation.  They have to do with
           start-up testing, and I will give you a brief summary
           of where we are on that, and the NPSH issue that was
           left to open.
                       And Kerry Kavanaugh is going to discuss
           that.  And then we will give some overall concluding
           remarks at the time.  So I am going to turn it over to
           Ralph at this time.
                       DR. POWERS:  Let me ask one question.  At
           what point do we discuss grid stability?
                       MR. CARUSO:  I'm sorry?
                       DR. POWERS:  At what point do we discuss
           grid stability?
                       MR. CARUSO:  Grid stability?
                       MS. MOZAFARI:  Well, we don't have a
           specific presentation on grid stability.  We could
           make people available at the end of the discussion to
           discuss that.
                       DR. POWERS:  Okay.
                       DR. SCHROCK:  I have one point that I
           would like to bring up and that is something that is
           not on the agenda here, and concerning LOCA
                       I think that the presentations so far have
           indicated that the increase in the peak clad
           temperatures is very modest, and that there is a huge
           gap remaining between the peak clad temperature and
           the 2200 degree limit.
                       But I was reminded that the SAFER method
           application under SECE -- I think 472 was the number
           -- resulted in a 1600 degree limitation being imposed.
                       And so I think the wrong impression has
           been conveyed and I think that ought to be clarified. 
           So where do we really stand with regard to what is the
           existing peak clad temperature limit in LOCA for Duane
                       And what was it previously under the old
           license provision, and what would it be under the
           extended power uprate?  So I think that another look
           at the comparison of those numbers is really in order.
                       MR. CARUSO:  This is Ralph Caruso from the
           reactor systems branch.  This was discussed quite a
           bit yesterday I thought by GE when they explained
           under the SAFER/GESTR methodology that licenses have
           to meet both the 1600 limit and the 2200 limit.
                       And I don't have the actual numbers here,
           but they provided the pre-and-post power uprate peak
           clad temperatures for both of those aspects of the
           methodology, and showed that the numbers did not
           change significantly, I believe, either one of them.
                       I guess I am not clear. Dr. Schrock, what
           your question is.
                       DR. SCHROCK:  Okay.  Perhaps I am the only
           on here that had this impression of the results as
           presented.  Both in the meeting yesterday and in the
           previous meeting on this topic, there was discussion
           about the large range above the predicted peak clad
           temperatures which is available.
                       And it was presented in the sense that 
           2200 is the applicable limit, and 2200 is the
           applicable limit in Appendix K and that is true.  But
           you have also imposed the 1600 degree limit for this
           particular licensing methodology.  
                       And also it was mentioned that, yes, there
           are some plants that do in fact have predicted peak
           clad temperatures close to the 2200 degree limit.  But
           in fact those plants are not analyzed by this method.
                       So what I am saying, Ralph, is that I
           think this is a matter which was presented in an
           unclear way, and I am asking for clarification.  Now,
           if I am the only one that sees it that way, fine, it
           doesn't need any.  I will then have to ask my
           colleagues if I alone in this?
                       MR. CARUSO:  Let me see if I can explain
           it again.  They have not just one limit of 1600, but
           they have to meet both the 1600 according to the upper
           bound calculation; and they have to meet 2200 by the
           licensing basis calculation.  
                       They do essentially two sets of
           calculations, and they have to meet both of those
           criteria.  They cannot just meet one or the other.
           They have to meet both, and they have to demonstrate
           that they meet both.
                       DR. KRESS:  Would you remind us of the
           reason for the 1600 degree limit?
                       MR. CARUSO:  The 1600 degree limit came
           because the data that was used to support the
           methodology did not include tests that went above the
           1600 degrees.
                       DR. KRESS:  So that was the basis then?
                       MR. CARUSO:  So that was the reason for
           the limit.  Recently, GE has asked us to relax that
           limit because they have some new data, and we are
           considering that.  
                       But right now the methodology, and
           methodology comprises a lot of different parts, but
           the methodology does include both an upper bound
           calculation to show that they meet the 1600 limit,
           plus an Appendix K type calculation to show that they
           meet the 2200 limit.  So they have to meet both of
                       CHAIRMAN WALLIS:  And the nomenclature of
           upper bound is a little bit confusing, because it is
           actually the lower one.
                       MR. CARUSO:  Right, and I understand that.
                       MS. ABDULLAHI:  If I may interject.  I am
           Zena Abdullahi, of the reactor systems.  And I just
           want to say that the Duane Arnold numbers -- and I
           think that GE and Duane Arnold can expand on it, but
           that the 2200 limit for Duane Arnold for the GE14 fuel
           is 1510, and which is the limiting, and it is 1350 for
           the 1600 limit, or less than 1350.
                       CHAIRMAN WALLIS:  That's what we had
           yesterday, and it was one of the unnumbered slides. 
           It is useful that they have numbers so that we can
           refer to them.
                       MR. CARUSO:  Right.  I guess I am not sure
           that I have answered your question, Dr. Schrock.
                       DR. SCHROCK:  Yes, I think you have.
                       MR. CARUSO:  Okay.  Good morning.  My name
           is Ralph Caruso, and I am the Chief of the BWR Nuclear
           Performance Section in the Reactor Systems Branch of
           the NRR, and I am going to talk this morning about the
           fuel and the reactor systems review that was done for
           the Duane Arnold power uprate.
                       I would like to start by giving you a bit
           of background.  This power uprate was not just an
           increase in power for the Duane Arnold plant.  It also
           included a change in fuel to GE14, which is one of
           GE's newest fuel lines.
                       And it also included a change in the power
           to flow map to use what is called MELLLA operation, M-
           E-L-L-L-A, maximum extended load line limit analysis
           method, which is needed in order to be able to get to
           the higher power level.
                       However, I wanted to make it clear before
           I start, and I will say this several times throughout
           my presentation, that even though the power limit was
           -- that the power will be changed at Duane Arnold, we
           are making no changes to the fuel burn up limits.
                       BWR fuel is licensed to a certain burn up
           limit, and that limit has not changed.  And in
           addition licensing limits have not changed as a result
           of this.  
                       So Duane Arnold has to demonstrate -- and
           we believe that they have demonstrated that they meet
           those licensing limits for this power uprate.  
                       DR. POWERS:  To be clear on this, it seems
           to me that it is also true that the staff has made an
           engineering judgment that at the license burn up limit
           on the fuel that the fuel will tolerate the ATWS
           transients, and that that has not been demonstrated by
                       But that a research program has been
           initiated to try to confirm that regulatory decision.
                       MR. CARUSO:  I believe that is a fair
           statement to make, Dr. Powers.  The review scope, we
           looked at the core, the fuel performance, reactivity
           characteristics, and all the aspects that we would
           look at during the normal review of this sort of
                       We used as a template for this review the
           ELTR-1, ELTR-2, and the supplement to ELTR-2, that
           were reviewed and accepted by the staff earlier, about
           5 or 6 years ago, for power uprates.
                       The analyses in the evaluations that were
           done by Duane Arnold and by GE are based on NRC
           approved methodologies, analytical methods, and codes,
           including the acceptance criteria that are described
           in those methods.
                       Because this was a rather large power
           uprate, we decided that we would include on-site
           audits as part of our review.  Duane Arnold was the
           first plant that we had done this for for a power
                       I am going to report that we found the
           process to be quite positive and useful, and we intend
           to continue to do it.  We looked at the safety
           analyses, and the performance evaluations that were
           prepared by GE and by the licensee.
                       And we determined whether they complied
           with analytical methods and codes that I have
           discussed earlier, and we used the EPU safety analysis
           report, NEDC-32980, as the guideline for this.
                       CHAIRMAN WALLIS:  How does this audit
           work?  Do you look over their shoulder while they ran
           a calculation or is it a formal process where they are
           on one side of the table and you are on the other?
                       MR. CARUSO:  No, we send a team, usually
           4 to 5 people, to the offices where the information is
           located, and GE has different parts of their
           organization doing different parts of their analyses,
           either in Wilmington or San Jose.  
                       And what we do is that we look at what has
           come in, and we look at what we have looked at
           recently, because we take history into account; the
           history at other plants, and the history in other
                       And we say to ourselves where do we think
           there are areas where we maybe don't feel comfortable,
           but where we would like to look.  And we target those
           particular areas, and we say, okay, licensee, where is
           this information located.  
                       And then we send a team of 4 or 5 people
           out there, and they will say that I want to look at
           the design record files for the ATWS analysis for this
                       And at this point in the review those
           analyses should already be completed.  There should be
           a set of analyses that has been reviewed, approved,
           quality assured, and documented.  And we ask for those
           design record files.
                       And this team of people will sit down in
           a room for a day or two, and jus read, and think, and
           read, and think.  And at the end of a few days, they
           have questions.  
                       And they go to the GE people and say I
           don't understand this, and where did this come from. 
           Why did you make this assumption.  Can you document
           for me that the operators will take this particular
                       CHAIRMAN WALLIS:  Like a Ph.D. defense.
                       MR. CARUSO:  That is the idea, and because
           the experts are right there, these audits are
           particularly effective.  They can ask the question and
           they can get an answer right away.  So that is the way
           that we do them.
                       A lot of this is background about what the
           criteria are,. and in the standard review plan,
           Section 4.2, that talks about fuel system design
           criteria for AOOs, and I believe that the criteria is
           that during AOOs that 99.9 -- 99.9 and not 99.99 --
           percent of the fuel will not undergo transition
                       That damage would not prevent control rod
           insertion, et cetera, et cetera, et cetera.  GE has a
           methodology that has been approved to ensure that
           analyses of AOOs demonstrate that they meet this
           criteria.  That is what we looked at.
                       In addition, the vendors perform thermal
           mechanical, thermal hydraulic, and neutronic analyses
           of the fuel to ensure that it meets the design limits
           that are specified as part of the fuel licensing
                       The fuel licensing criteria are another
           set of or is another document which allows the vendors
           to design fuel, to build it, and to use it in
           reactors.  So we review the application of these
           methodologies to the plant in question, and in this
           case, Duane Arnold.  
                       DR. POWERS:  Is this the appropriate point
           to ask about the COBRA-G evaluation of GE14 fuel?
                       MR. CARUSO:  I'm sorry, the COBRA-G?
                       DR. POWERS:  The COBRA-G, yes.
                       MR. CARUSO:  I will get into that in a
                       DR. POWERS:  Okay.  
                       MR. CARUSO:  I am still to a certain
           extent in background here, and I am going to try and
           move along.  The thermal limits evaluation for Duane
           Arnold was performed using what is called an
           equilibrium core.  
                       They will establish an operating condition
           that is expected to occur after a certain number or
           reloads, where the plant is essentially operating in
           a steady state mode.  
                       It has completely been loaded with the
           particular type of fuel, and in this case, GE14 fuel,
           and it is operating from one cycle to another cycle at
           the -- how do I want to say this -- the term is the
           equilibrium core.
                       And which is the state that you reach
           after you load the same type of fuel using the same
           core design parameters over a number of cycles, and
           eventually reaching an equilibrium state in terms of
           core design.  And once again operation -- considering
           the MELLLA rod line and the 20 percent power uprate.
                       One thing that I would like to mention is
           that although these analyses were done for an
           equilibrium core, thermal limits are established or
           confirmed for every individual reload, because you
           don't have the equilibrium core starting from the
           first core.
                       So GE or any other vendor, they do thermal
           limits analyses to verify that the core as designed
           and as installed meets those thermal limits.  And they
           publish the results of those analyses in something
           called a cooperating limits report.
                       And very often they have to submit to us
           a techs spec change because they change a parameter in
           the tech specs called a safety limit minimum critical
           power ratio.
                       And we have actually done the review of
           that safety limit ratio for Duane Arnold.  I think I
           signed it out the other day.  And that is a number
           that varies between about roughly 1.09 and 1.12 or
                       And the methodologies for establishing
           that number are well understood, and we do that review
           just about every cycle.  And once again I want to make
           it clear that there are no changes to any burn up
           limits for this fuel.  
                       A power uprate does not allow anyone to
           exceed currently established burn up limits.  
                       DR. POWERS:  And I will hasten to add
           again that those are based on a judgment that they
           will in fact survive reactor transients.
                       MR. CARUSO:  I understand that.  I am
           trying to make this point as often as I can because
           some of the questions that have arisen imply, or
           actually state that, well, because you are going to do
           a power uprate that the fuel is going to be burned to
           a higher burn up value.
                       And I want to make it clear that that is
           not the case.  The fuel may be burned faster and some
           of the fuel may experience a higher duty than it would
           otherwise see.  But the actual burn up limits, the
           amount of gigawatt days per metric ton that you can
           get out of the fuel, has not changed.  
                       DR. KRESS:  The average has changed
                       MR. CARUSO:  The average has changed, but
           the peak bundles, the bundles that are most limiting
           in these analyses, have not.
                       DR. KRESS:  Yes, most limiting, in terms
           of the regulatory compliance with Chapter 15 DBAs.
                       MR. CARUSO:  That's correct.
                       DR. KRESS:  But when we think about PRAs
           and risk, we think about the average.
                       MR. CARUSO:  That's correct.  The decay
           heat has indeed gone up.  So there are some scenarios,
           for example, of shut down cooling, where there is less
           time available.  
                       I believe there was a significant
           discussion about that yesterday, and that situation
           does exist.  But for fuel licensing, those limits have
           not changed.
                       I have a lot of background here on
           stability.  I don't want to spend a lot of time on it
           because we have talked about this quite a bit
           yesterday.  Let me see if there is any slide here that
           I need.
                       CHAIRMAN WALLIS:  Are you going to come
           back to this business of the up-skew and down-skew?
                       MR. CARUSO:  I am going to get to that. 
                       CHAIRMAN WALLIS:  Okay.  
                       MS. ABDULLAHI:  Ralph, I think you passed
           that under the on-site audit.  
                       MR. CARUSO:  Let's see.  
                       MS. ABDULLAHI:  You have to excuse us.  It
           is not numbered.  
                       MR. CARUSO:  I thought I had a slide in
           here that talked about that, and I was going to be
           getting to that.
                       MS. ABDULLAHI:  I think you passed it
           already, Ralph.
                       MR. CARUSO:  I did?
                       MS. ABDULLAHI:  The staff EPU audit, and
           it is right after fuel design and operations.
                       CHAIRMAN WALLIS:  That's the one that I am
           looking for.
                       MR. CARUSO:  Oh, okay.
                       CHAIRMAN WALLIS:  That is the one that you
           kept saying that you were getting to, and you left it
                       MR. CARUSO:  I'm sorry.  You know what? 
           I think it mis-fed through the feeder, and I don't
           have that slide as a slide.  Okay.  What I did -- I
           have the printouts here, but I have a set of slides,
           and I think maybe it got double-fed.  So I didn't get
           a copy of that one.  So I don't have a slide for that
           one.  But I can talk from it.
                       One of the reviews that we looked at, one
           of the areas that we looked at during the review was
           the fuel system design.  In this case, for GE12 and
           GE14 fuel. 
                       And during the course of the review, we
           discovered that GE had used some data that was
           generated by a code known as COBRA-G to be included a
           database for a correlation that is known as GESTR-14. 
           I think it may have been known as GESTR-10 at the
                       And as part of the review, we actually get
           into the details of these correlations.  We look at
           the data, and we say where did this data come from.  
                       We can look at the quality assurance for
           it.  And in the case of this one particular heat
           transfer correlation, the staff discovered that some
           of the data did not come from a test facility, but
           came from a computer code.
                       And we questioned that, and we held some
           pretty intense discussions with General Electric about
           this.  And in the end, we convinced them that they
           should not use this data.  And as a result, what they
           have done is that they have backed it out of their
           database, and they have revised their correlation.
                       And they have followed their procedures in
           their corrective action plan to revise the correlation
           and redo assessments or calculations as necessary to
           reflect those changes.  It is the same sort of thing
           that they would do if they discovered an experimental
           data was not correct.
                       So as I say in this slide, we believe that
           they are taking appropriate action.  They have taken
           appropriate action, and we think that this issue is
           resolved for Duane Arnold.
                       Yesterday though I received -- actually in
           this room, very room, I received GE's submittal from
           Glen Wattford who is sitting somewhere in the back
           there, with new information about this correlation.
                       And the staff will be reviewing it.  They
           have gone out and they have additional data available
           that they had not used in this correlation.  
                       They have decided now to use that data,
           and they made a staff submittal, and the staff will
           review it.  But I want to point this out because this
           is an example of the sort of information that we have
           discovered as a results of this on-site audit that we
           would not necessarily see as part of an in-office
           audit, for example, or a review in the office.  So
           that is one of the successes of this. 
                       CHAIRMAN WALLIS:  I think it is also good
           that they have submitted a document, and I think we
           often get uneasy when a matter is resolved by a
           promise to take appropriate action, and we don't have
           a process for checking that it has actually happened.
                       MR. CARUSO:  Well, I will leave it at
           that, and I will agree.  I think in this case that GE
           and the licensee have been very cooperative.  We have
           honest technical disagreements, and honest differences
           of opinion on this.
                       But in the end, we convinced them that our
           position was the correct one, and they have processes
           to deal with this, and they followed them.  Let's see. 
           What else.
                       DR. POWERS:  What I did not see in the
           discussion in the SER was the adequacy and
           applicability of the data that were accepted by the
           staff, especially with respect to power profile.
                       MR. CARUSO:  That actually gets treated as
           part of the methodology.  They have to take
           uncertainty penalty factors.  If you don't have enough
           data to support a particular profile, then you have to
           take a penalty factor for that.  And that is in the
                       One of the questions that has come up
           about these power uprates is margins, and who owns the
           margin.  I think there was a discussion about that --
           was that this morning.  No, yesterday.
                       DR. POWERS:  Well, I think it is not only
           a discussion that took place yesterday, but it is a
           discussion that has taken a long time, and I think
           that everybody at the table agrees.  So I would
           suggest that you just move on.
                       MR. CARUSO:  Fine.  Stability.  As I said,
           Duane Arnold is a 1-D plant and they do detectance,
           suppress --
                       DR. POWERS:  Let's be clear.  1-D does not
           mean that they are one dimensional.  
                       MR. CARUSO:  That's correct.
                       DR. POWERS:  In fact, they are a multi-
           dimensional plant, and 1-D is an option corresponding
           to the ATWS.
                       MR. CARUSO:  They are an Option 1-D plant,
           and the solution to the stability issue for Duane
           Arnold involves implementation of Option 1-D.  As part
           of the on-site review, the staff discovered a document
           which questioned the applicability of the generic
           Divom curve.  
                       The Divom curve is -- and I am going to
           need help on this at some point if you get too much
           into the details, but it is the delta CPR over initial
           CPR, versus oscillation magnitude curve, and it is a
           generic curve which is supposed to be applicable to
           all BWRs, which is an input to the on-line stability
           monitoring systems.  
                       And during the review the staff discovered
           an internal GE document which questioned whether the
           existing Divom curve was applicable or appropriate for
           plants.  And this also applied to any plant that used
           GE14 fuel.
                       And as a result, GE has issued a Part 21
           report on this Divom curve, and the number of plants
           -- all the BWRs in the country are in the process of
           responding to that Part 21 notice by either taking
           corrective action to go back to interim manual
           corrective actions, where they have on-line stability
           monitoring systems for the use of interim conservative
           versions of the Divom curve.
                       This is an ongoing process, and let me see
           if I have the slide here.
                       CHAIRMAN WALLIS:  So actually the core-
           wide oscillation is one-dimensional isn't it? 
                       MR. CARUSO:  No, I don't want to say that. 
           It is core-wide.  I don't know that I would say that
           that is one-dimensional.
                       CHAIRMAN WALLIS:  Okay.
                       MR. CARUSO:  Okay.  As I say here, GE
           discovered that the generic regional mode Divom curve
           is strongly affected by the peak bundle power, and
           there may be some plants operating with high peak
           bundle powers, where the Divom curve did not consider
           that they could be operating.
                       GE has recommended that licensees use a
           particular figure of merit to determine whether they
           have a problem in this area.  For Duane Arnold, that
           particular figure of merit is such that the Divom
           curve for Duane Arnold continues to be appropriate. 
           I don't believe that they will have to change their
           Divom curve.
                       So for Duane Arnold, this is a resolved
           issue.  For a number of other plants though,
           additional calculations will have to be done, and this
           is being done under the egis of the BWR Owners' Group.
                       And yesterday, or two days ago, excuse me,
           they presented us with a plan for redoing the
           calculations and redeveloping the Divom curves.  And
           that plan takes into consideration individual plants'
           needs and fuel that will be loaded into the plants,
           and I believe it has completion date of sometime late
           next year.
                       The staff will be receiving a submittal
           sometime in the late second quarter of next year, and
           hopefully we will complete our review by the end of
           the next calendar year.
                       This is another example of an issue that
           we discovered as a result of an audit that we would
           not have otherwise have found.
                       CHAIRMAN WALLIS:  What is the basis of
           this Divom curve?
                       MR. CARUSO:  I am going to ask for help on
                       MS. ABDULLAHI:  GE should address that in
           this case.
                       MR. POST:  This is Jason Post of GE. 
           Their TRAC-G calculations is a fully coupled
           calculation, and each peak of a growing oscillation
           produces an oscillation magnitude, and TRAC directly
           calculates CPRs.
                       So you have a CPR change versus an
           oscillation magnitude, and we normalize those factors
           to produce the Divom curve.  
                       CHAIRMAN WALLIS:  So it is an entirely
           theoretical --
                       MR. POST:  Yes, it is theoretical, and of
           course TRAC-G has been used to benchmark actual
           instability events, and so we are pretty confident
           that it does a good job of doing that.
                       CHAIRMAN WALLIS:  Oh, it has been
           benchmarked against oscillatory events?
                       MR. POST:  Yes.  Yes, it has.  
                       DR. POWERS:  Were there others?
                       MR. POST:  There were some KLL specific
           tests that we benchmarked, and there was another event
           in Cofrontaes (phonetic) that was an unplanned event
           that we benchmarked.
                       There were also some earlier events at
           Caruso in Italy.  So there were a number of overseas
           events that we benchmarked.  
                       MR. CARUSO:  Jens, did you want to say
                       MR. ANDERSON:  This is Jens Anderson. 
           Yes, I just wanted to make a comment, but I think
           Jason made most of the comments, and there have been
           a fairly extensive qualifications basis.
                       Maybe one additional point that I would
           like to make is on oscillatory testing, and ATWS
           capability --
                       MR. CARUSO:  Okay.  As part of all of
           these reviews of fuel, the staff also considered the
           operability of the supporting systems.  For example,
           the ECCS system, the RCS system, the recirculation
           system, to make sure that these systems are not
           operating outside their design basis, and could
           provide appropriate support to the reactor so to
                       So this was part of the standard review,
           and we did not identify any particular operation of
           any of these systems that would call into question
           operation at the higher power level.  
                       It should be noted that some of these
           analyses will continue to be rerun throughout the life
           of the plant as the core reloads change, and as the
           limiting transients and accidents change through the
           life of the plant.
                       So even though we have done this review at
           this point, and the licensee has documented their
           analyses, those analyses continue through the life of
           the plant.
                       One of the audit calculations that we
           looked at was the ECCS analyses for Duane Arnold.  We
           looked at the methodology of SAFER/GESTR, and the
           results, and we didn't discover any problems.  It was
                       One of the systems that I think people
           have been concerned about has been the standby liquid
           control system because of its importance to the ATWS
           scenario.  Standby liquid control is a manually
           operated system.  
                       The license confirmed to us that it can
           actuate, and it can inject the required amount of
           boron into the system when called upon to do so.  We
           believe that they have demonstrated that the SLC
           system would be able to inject the required amount of
           boron into the reactor vessel during an ATWS.  
                       This is a conclusion concerning reactor
           transients, and just a description of the fact that
           they did do the analyses, and they will reanalyze them
           and reconfirm the results for every particular reload,
           and they used approved methods, and the results met
           the acceptance criteria.
                       For ATWS, they met the ATWS mitigation
           features.  10 CFC 50.62 specifically requires the
           installation of alternate rod insertion, and reactive
           recirc pump trip, and standby liquid control boron
           injection capability, and they meet those
                       One of the questions that the ACRS asked
           was whether there should be an automatic standby
           liquid control system installed.  In looking at this
           matter, my recommendation at this point is, no, I
           don't want it.  
                       And we have identified a scenario which --
           well, I don't want to overstate this because we are
           just in the very early stages of looking at this.  But
           if the standby liquid control system initiates too
           soon during a transient, there could be difficulties
           that are caused by actuation too soon because of the
           way that the system is piped, and the way the relief
           valves in the system are installed.
                       So automatic actuation of the standby
           liquid control system is something that would need to
           be considered very carefully.
                       CHAIRMAN WALLIS:  Well, if it is done too
           soon, it could be programmed not to do it too soon. 
           And you have the same problem with an operator doing
           it too soon.
                       MR. CARUSO:  That's correct.
                       CHAIRMAN WALLIS:  And between the operator
           and the automatic, it is not really based on having
           discovered a new scenario.  
                       MR. CARUSO:  Well, actually, if you do it
           automatically, you have to think about the timing, and
           what sort of signals cause the actuation.  
                       Operators are not as reliable as automatic
           actuation systems.  They take a while to react and to
           respond, and we hope that they think about what they
           are doing.  So there is a certain amount of delay
                       But we are reluctant at this point to say
           that there should be an automatic standby liquid
           control system actuation.  I'm sorry, a question?
                       AUDIENCE:  What defines too soon?  Is it
           10 seconds, 5 seconds?  Does anybody have a feel for
                       MR. CARUSO:  Well, looking at the pressure
           traces, it looks like it is within five seconds or so
           after the initiation or the detection.  I believe
           there is a signal called an ATWS alarm, or a ATWS
           signal, that occurs.
                       And I don't think you would want to have
           the standby liquid control system initiate off of that
           particular signal.  I don't want to get into this in
           too much detail because it is something that we just
           recently discovered, and we have not thought about it
           very much.
                       DR. POWERS:  I would like to go back to
           your existing recovery, and recommended recovery
           process for an ATWS.  The strategy of dropping the
           core level and injecting boron, and bringing the
           coolant level back up was developed considering a
           particular core power profile that was common at the
           time that the strategy was developed.
                       We don't have that particular power
           profile now in the plant.  The collapse liquid level
           is actually being dropped down below the top active
           fuel in this strategy.  
                       How does the revised power profile that is
           being envisioned for Duane Arnold and the power uprate
           affect that strategy?
                       MS. ABDULLAHI:  I think that GE would like
           to make a response to this issue, and then I would add
           if need be.
                       MR. POST:  This is Jason Post.  The
           dissolution was originally developed, including
           MELLLA, and if you take a recirc pump -- the impact of
           MELLLA is that Duane Arnold could operate at 99
           percent of their new rated power, or I'm sorry, a
           hundred percent of their new rated power at 99 percent
                       Previously, any plant with MELLLA could
           operate at the point corresponding to 105 percent
           power uprate at 81 percent of their license flow.  So
           those are an equivalent rod line, and if you take a
           pump trip from either one of those two cases.
                       And a flow run back to the natural
           circulation point, you end up at very close to the
           same power level, because it is really controlled by
           what the rod pattern, and that is what sets the power
           level at the end of the run back.
                       DR. POWERS:  You will be stunned at how
           little of which you just said I understand.
                       MR. POST:  Sorry about that.
                       DR. POWERS:  I got all the articles, but
           none of the nouns in there.  It didn't make any sense
           to me at all.
                       MR. POST:  We had a power flow map up
                       MS. ABDULLAHI:  If I can interject and
           maybe if it would be of any help, in the ATWS
           stability generic analysis that were done, they were
           based on certain powers, and certain power densities,
           and rod lines.
                       And the power, for instance, that they
           were based on if I recall -- and it is seen in a table
           called 5-1, it was 33233138, and that power level
           compared to Duane Arnold is higher.
                       And then if you look at the power density,
           it seemed high, and whether Duane Arnold's now would
           be higher than this, I can't confirm right now.  But
           just to give you an idea that these bounding analyses
           could have had some basis that covers it.
                       DR. POWERS:  I think what you are telling
           me is that the analyses were done for plants with much
           higher power than what Duane Arnold plans to go to
                       The issue, of course, is how about the
           power density in the froth region, or two-phase
                       MS. ABDULLAHI:  I would also have Tony
           Ulses intervene as well.
                       MR. ULSES:  This is Tony Ulses of the
           staff.  Actually, if I understand your question, Dr.
           Powers, you are really questioning the effect of
           lowering the water level to down low and whether or
           not these new operating strategies would affect any of
           the assumptions that went into the acceptance of that
           original philosophy.
                       Is that the question really that you are
                       DR. POWERS:  That is basically the
           question.  My recollection is that when the strategy
           was originally proposed the staff resisted the concept
           of bringing the collapsed water level down below the
           top of active fuel.
                       We had a particular power level in that
           phase region for those discussions.  Now we have a
           different one, and does it change the discussion.
                       MR. ULSES:  This basically goes into the
           concept of what is called the minimum steam cooling
           reactor water level, which is basically what we say
           you can go down to, and you will still have enough
           flow of steam to keep the upper portion of the fuel
                       And if you look at how that was generated
           -- and if I get off-base here, Jason, let me know. 
           But what I recall is that that was actually calculated
           with an extremely conservative top peak axial power
           distribution, which is even larger than what they are
           going to go to with these modern reactor operating
                       So therefore they will still be covered by
           the existing minimum steam cooling reactor water
           level, and so that will still be applicable.  
                       DR. POWERS:  Is this the result of an
           analysis, or is this the result of your impromptu
                       MR. ULSES:  This is the result of a
           calculation that was done quite a bit of time ago.  I
           believe it was like in the '80s or the '70s as I
           recall when this original concept was originally
                       MR. POST:  The mid-1980s.
                       MR. ULSES:  The mid-1980s, and it has been
           used ever since in the ATWS operating strategies.
                       DR. POWERS:  I am quite sure that you have
           not -- that you did not anticipate in that calculation
           what Duane Arnold was going to do with their power
                       MR. POST:  This is what I was trying to
           say earlier.  Right now at their extended power uprate
           with the MELLLA line, Duane Arnold could go between 99
           percent and a hundred percent of rated flow.  
                       Previously, if they would have had MELLLA
           at this power level, they could have operated it at
           this point, which would be 81 percent of their flow. 
           These two points are on the same rod line.
                       So if you take a pump trip from that
           point, or a pump trip from this point if they had
           operated with MELLLA, both of those pump trips would
           run down to the same point at natural circulation, and
           basically at that point right there.
                       So both conditions end up there, and since
           plants had MELLLA when we developed that solution
           originally, we were modeling a condition that is the
           condition that Duane Arnold is moving to today for
           their application.
                       DR. POWERS:  Thank you.
                       MR. CARUSO:  I guess that's all I have to
           say about reactor and fuels.  If you have any
           questions, I am available, or we can go on to the next
                       DR. POWERS:  Do the members have any
           additional questions they would like to ask about
           reactor fuels?  If not, I think we can go on.
                       MR. WU:  My name is John Wu from NRR, and
           I am here today for this material degradations. 
           Actually, this material degradations is mostly
           materials and parts, and it seems that my part is the
           flow induced vibration is one of the issues that has
           come out.
                       So that's what I am here for.  And so that
           is what I am going to cover, is this topic, and others
           related to corrosion and erosion I will give to the
           material people over there.
                       And first of all, we start with the
           reduced power uprate, and I think that this flow
           induced vibration mostly was covered by GE yesterday,
           and so I will just quickly go through this and take
           any questions if there is any.
                       This power uprate mostly -- while the
           reactor pressure has no change, there is no change on
           temperature, and no change on the flow rates, or core
           flow rate.  
                       And also there is no or very little change
           in the drive flow because we generated more steam, and
           we have a bigger pressure drop.  So the drive flow is
           increased a little, which I understand is 2.5 percent.
                       And mostly we have a steam flow increase. 
           So because there is no core flow increase, and if you
           look at the component inside of the reactor affected
           by the core flow, such as the guide chip, et cetera,
           those become -- and also the in codes, they are the
           code -- like the fuel banding, they are not affected.
                       But only a few components are affected,
           like the drive flow at 2.5, which is very minimal. 
           But GE have been varying those based on their recorded
                       And the results come up to the results
           that the vibration level is below the acceptance
           limits.  That is the acceptance limits of -- they have
           vibration -- you know, they can monitor and the
           calculation illustrates the vibration stress level,
           which is less than the endurance limits.  That is what
           GE put on it as being the criteria.  
                       And based on that the endurance limits are
           acceptable, and anything in other components -- you
           know, every component, if their vibration is less than
           endurance limits, and it means that they are not
           getting into the picture of a particular calculation,
           because the fatigue factor -- the cumulative factor,
           or the cumulative fatigue usage factor is not required
           in the design basis, and is zero, and it is below the
           acceptable limits.
                       And as a matter of fact, in the GE
           submittal, they put acceptable -- for 10 KSI, but that
           is very conservative compared to ASME 13.6 KSI.  So,
           7.6 KSI if you look at the fatigue curve in the ASME,
           you will see that corresponding to about 10 to the
           11th endurance limits.
                       So, therefore, in the upper -- steam flow
           affected by the increase of steam flow are the
           components of dryer and separator.  I think that GE
           made a presentation yesterday that the dryer and the
           separator there are not -- they are not separate
           components, and that is mostly that they don't have --
           for that.
                       But since we asked the question how is
           this affected by flow induced vibration, they look at
           their data for the separator, and the separators data,
           the data for the separators, the data shows that the
           vibration acceptable level is about 15 percent of the
           acceptance limits.
                       CHAIRMAN WALLIS:  We heard yesterday that
           there were cracks observed in these devices.  So it is
           acceptable for some things, but you have --
                       MR. WU:  There is no crack on the
           separator, but the dryer, in the dryer, they did find
           some, and they also looked at the dryer.
                       DR. FORD:  Did you during the analysis 
           -- and I recognize that they are not safety related
           components as such, but in relation to what was
           discussed yesterday by GE, they are not safety related
           components, the dryers and separators.
                       If they did fail either by stress
           corrosion cracking in the channel, in the bottom of
           the dryer, or by fatigue of the vains in the dryer,
           and they came lose, how would that affect the overall
           safety of the reactor as such, and was that evaluated?
                       MR. WU:  Yes, we also asked the questions,
           asked GE the same question about it.  The design
           criteria, as such, the dryer has to stay intact, and
           structure integrity has to be maintained.  
                       During a pipe break, or during the steam
           line break because worrying about the dryer, goes to
           the steam dryer, and -- you know, it stops the
           operation, and so that has to be calculated to ensure
           that structural integrity of this dryer.
                       And also because the power uprates, we
           evaluate those to meet the design basis, and we
           approve in the ELTR-1 and ELTR-2.
                       CHAIRMAN WALLIS:  I guess my comment went
           to the consequences of these things failing, and you
           are telling us that the consequence that you worry
           about is the pieces go down the steam line?
                       MR. WU:  Yes, that is what a design
           criteria -- 
                       CHAIRMAN WALLIS:  Could they not go around
           in the --
                       MR. WU:  No, the flow induced vibrations
           is what you are talking about.
                       CHAIRMAN WALLIS:  Where do the pieces go
           when they break?
                       MR. WU:  Well, there is no problem with
           that.  We still try to ensure integrity during
           operation, and such as like -- well, I think GE looked
           at similar plant, and they didn't find a crack on this
                       CHAIRMAN WALLIS:  I think the problem that
           we are all having is regardless of what the codes say,
           there have been failures by stress corrosion cracks
           and flow induced vibration in the steam dryer
           separator units.
                       MR. WU:  I am not sure it is from the flow
           induced vibration.
                       CHAIRMAN WALLIS:  Well, regardless of
           whether it is flow induced vibration, or whether it is
           stress corrosion cracking, they failed, regardless of
           what the codes say.
                       MR. WU:  Yes, they failed.
                       CHAIRMAN WALLIS:  And so actually the
           codes don't really mean much as far as maintaining
           integrity, and the question we are asking from a
           safety point of view is if these things come lose,
           what do they do?
                       MR. WU:  So that is why we are looking at
           if those things come lose or will come lose, and if
           not, then we don't have to worry about it.  So that is
           -- well, we look at what are the reasons for the dryer
           to fail or crack.
                       I think that what GE found out was that
           the crack was due to turning the turbine off, and
           closure, and the flow trenching, like the TSB closure,
           and --
                       CHAIRMAN WALLIS:  I still have trouble
           relating the answer to the question.
                       MR. WU:  Well, that is what I am trying to
           address.  The crack is not due to -- well --
                       MR. KNECHT:  This is Don Knecht from GE
           here.  Let me try to add some clarification here. 
           There is a couple of points.  One is the cracks have
           been found in the dryer assembles have all been
           identified early enough that they can be repaired so
           that they don't become a lost part during the upcoming
                       And so there has never been a case where
           there has actually been a lost part from these
           components.  Now, if it did happen for some reason,
           the cracking is generally in the lower part of the
           dryer where the conditions are more conducive to
           stress corrosion cracking or vibration fatigue.
                       And failures in that location are going to
           stay below the dryer and not reach out in that area
           and into the steam line.  They are not -- unless they
           are very, very small, they are not going to drop back
           through the separator under the conditions where we
           have low power, and we are shut down or what not.
                       And even if they did, they are not going
           to find their way all the way down into the fuel area
           where they will cause damage.  So we have not done
           formal lost parts analyses on these, on the dryer
           pieces, at least not that I am aware of.
                       And the size -- well, the parts that might
           be lost because of this cracking are most likely large
           enough that they would not cause a problem and that
           would get out of the dryer area.  So I hope that
           clarifies it.
                       DR. FORD:  I don't know who to address the
           question to now, but there have been, for instance --
           and still sticking to that one unit, there have been
           stress corrosion cracking of the brackets that hold
           the steam dryer assembly up.
                       What would happen -- those are not
           protected currently by --
                       MR. KNECHT:  Correct.
                       DR. FORD:  What would happen because of
           the general stressing nature, and increased by 31
           percent -- and I think that was the number that was
           given for the dryer, what would happen if you got a
           whole dryer that fell down?
                       And I recognize that would be an extreme
           event, but what would happen then?  It wouldn't be
           just a small part.  It would be a thumping great big
           component.  Is that possible?
                       MR. KNECHT:  Well, it only requires 3 out
           of the 4 support brackets to hold a dryer.  So if
           there was cracking in one of them, that would be
           detected and repaired, and that would not be a
                       Now, if for some strange reason you had
           multiple failures, the dryer would settle, and there
           would be a noticeable decrease in steam flow, and an
           immediate shutdown of unknown conditions.  
                       DR. FORD:  If it was laying on top of the
           separator, it would just sit there?
                       MR. KNECHT:  Well, you wouldn't have the
           steam flow that you would expect.  
                       CHAIRMAN WALLIS:  Would it make that much
           difference to the steam flow?  Would it just be
           diverted, and increase the pressure drop, but that's
           not a significant component of the overall pressure
           drop is it?
                       MR. KNECHT:  Well, normally it only has a
           very small pressure drop, but I think it would a flow
           blockage.  But a complete one, of course, but it would
           be --
                       MR. WU:  But this is for the same --
           according to their submittal, the occurrence occurs at
           the outer bank close to the impact nozzle, and -- is
           four times of that, and so there is no history of that
           for the Duane Arnold.  
                       So, either there is no such thing, or is
           there no history for the -- is already 113 percent. So
           if we wanted to look at the operating experience, the
           cracking -- and we can ensure that it is okay.  And
           here we are looking at flow induced vibrations to see
           if there is anything like that.
                       And there is no data and we looked at the
           dynamics of a pressure drop -- and it is about 10
           percent of the -- and so the flow increase 20 percent,
           and the vibration level increased 50 percent.  So,
           that is 1.7 or about -- and so you can say that you
           can get some reasonable assurance --
                       CHAIRMAN WALLIS:  You are saying that it
           is far from its endurance level?
                       MR. WU:  It is far from their margin with
           respect to the dryer, yes.  And the flow separators
           did not vary.  The separator is about 15 percent
           according to their data -- and if it were to increase
           by 50 percent, you would have about 22 percent.  So
           that is a big margin there, and because of this big
           margin, it gives us a good feeling about this.
                       CHAIRMAN WALLIS:  Well, have they tested
           these dryers and separators at the specific conditions
           that they are going to be operated at with the power
           uprate in separate effects tests?  
                       I think we asked that question yesterday,
           and I believe the answer was yes yesterday, and it
           seemed to be a very quiet yes.  I mean, that's what I
           would to see.  
                       I mean, flow induced vibrations, there are
           resonances and things that happen, and when you scale
           up this is based on some assumptions, and it is much
           more reassuring to say we have actually run this
           thing, and we have measured the vibrations under the
           conditions, and they are indeed small or some measure.
                       DR. FORD:  I think maybe the question
           yesterday was asked in the context or at least a
           question was asked yesterday in the context of you
           extrapolating out, and do you have any data to bound
           that extrapolation, and that was in relation to the
           corrosion, and not the flow induced vibration.
                       CHAIRMAN WALLIS:  Well, I meant flow
           induced in terms of vibration.
                       DR. FORD:  Okay.  But it was mentioned in
           relation to the flow assisted corrosion that this was
           a fairly low flow rate plant in comparison to the rest
           of the fleet.  
                       So are there other reactors, and not Duane
           Arnold, out there which you have used in your
           evaluation to answer this question that Dr. Wallis
           asked?  Is there data out there that would bound these
           flow rate conditions, or vibration conditions, in
           other plants?
                       MR. WU:  In other plants such as -- well,
           Monticello and Hatch?
                       DR. FORD:  Or whatever.
                       MR. WU:  Yes, whatever, and GE has generic
           testing of up to 13 percent, or all the way up to 13
           percent.  So they are bounded by those.
                       DR. FORD:  No, I think the question is are
           there data in other operating plants operating -- and
           it would be at these same flow rate conditions --
           which have been operating successfully.  I mean, that
           is the question that is asked.
                       MR. WU:  That is the question which --
           that is the data that we tried to get before, and for
           some reason we did not get it, because --
                       CHAIRMAN WALLIS:  My question was somewhat
           different.  I thought that these things were tested in
           separate effects tests.  You test one separator and
           one dryer, and you can run that up way above what you
           get in the plant just to reassure yourself that you
           are extrapolating or interpolating.
                       But that would be nice to see and would be
           convincing, and it wouldn't just be -- and if you
           could show that everything is scaled, then that is
           fine, too.
                       But just to sort of extrapolate out there
           on the basis of a theory without any data to hang it
           on sounds a little bit dangerous.
                       MR. WU:  I think they used to calculate
           that with the extrapolation of system data, and --
                       CHAIRMAN WALLIS:  Maybe this could be
           answered before the full committee meeting or
           something.  I am not sure we are getting an answer.
                       MR. SHUAIBI:  This is Mohammed Shuaibi
           from the staff.  If we can take that question back,
           maybe we can come back at the full committee and
           address it.
                       CHAIRMAN WALLIS:  Maybe it would help if
           there were a written reply to the subcommittee before
           the full committee meeting so that we didn't have to
           go through trying to extracting the answer orally, and
           we could say, yes, we have read it and we think it is
           okay or not.
                       MR. SHUAIBI:  We could certainly do that.
                       DR. FORD:  The specific question is that
           given the fact that there have been flow induced
           vibration induced problems in dryers in the past are
           there any data, either in the laboratory or in full
           scale, or in the operating plant, which justifies that
           there will be no problem, and specifically at Duane
                       CHAIRMAN WALLIS:  That seems a simple
           question to answer.
                       MR. SHUAIBI:  Justifies that there are no
           problems at Duane Arnold?  
                       DR. FORD:  Yes.
                       MR. SHUAIBI:  We will take that back.
                       MS. MOZAFARI:  That justifies the
           assumption of no problems at Duane Arnold.  
                       DR. FORD:  Because saying you are adhering
           to the codes when there have been failures doesn't say
           too much about the code.
                       MR. SHUAIBI:  We will take that back and
           we will provide an answer.
                       MS. MOZAFARI:  Okay.
                       DR. POWERS:  Let me ask a question on a
           different answer, but that is still related to 
           materials and fatigue.  The licensee has adjusted his
           methodology for looking at cumulative usage factors
           and in most cases saw a substantial drop in cumulative
           usage factors for fatigue.
                       In one case, however, he reports a fairly
           substantial increase in the cumulative usage factor,
           and in particular I believe for the feed water
           nozzles, I believe he shows a cumulative usage factors
           coming up very close to one.
                       Did the staff examine the methodology, and
           in particular did they look at the feed water nozzle
                       MR. WU:  The methodology that GE used is
           with respect to Appendix I in the ELTR-1.  They said
           they followed Appendix I of ELTR-1, which we had
           approved before.
                       And the methodology says to compare the
           inputs parameters, and the EPU parameters, and to
           identify the inputs, and they don't have to do
           anything.  And if it is not -- they have to do -- to
           get a scaling factor, conservatively based on whatever
           is -- well, the pressure temperature difference, and
           to come up with some scaling factor.
                       So they multiply the scaling factor and
           multiply by the existing stress and that ends up to be
           the -- and so the methodology that we approve, there
           are no problems.  So because this is a scaling factor
           multiplied by the stress, the existing stress, the
           stress factor they use is really conservative.
                       So anything below 1.0 -- and as a matter
           of fact, we know that the stress is not limited to the
           -- it is the total stress, also including the others.
                       DR. POWERS:  You are going an awful long
           way around the barn to answer what is a fairly simple
           question.  What I want to know is did you look at the
           methodology, and I think the answer is yes.
                       MR. WU:  Yes.
                       DR. POWERS:  And how the question is did
           you look specifically at what they had done for the
           feed water nozzles, and do you concur that the
           cumulative usage factor is less than one for that feed
           water nozzle.
                       MR. WU:  Well, we did look at the details
           and their methodology.
                       DR. POWERS:  That's all I needed to know.
                       MR. WU:  Also, we looked at the details of
           some of the usage factors.  I mean, there are lots. 
           It is from .9 something way out to .199.  And it goes
           down.  So how come it goes down that much, and the
           answer we got is that in the past they used the worst
           condition, based on the worst condition.
                       And the worst condition is the loss of the
           feed water, and that is the worst, and from there they
           got -- let's say it is one, for instance, and from
           that they got the allowable cycle.  And then they used
           the allowable cycle, which is normally small, and used
           or ate up all the cycles and that is too conservative.
                       So now they come back to do or to take for
           each one, and for each one it is a different transient
           for each transient, and maybe for 2 or 3, and after
           the three, they use that number three for the rest.
                       DR. POWERS:  Well, it's just that I find
           it remarkable that everything drops down, and for
           understandable reasons.  And here is one case where it
           goes up, and it seems logical that it should be a
           substantial fatigue for the feed water nozzle.
                       And it gets close to one and you don't
           check to see if you agree.  I mean, it is within four
           percent of one.  I can't or I myself cannot calculate
           cumulative usage factors up to four percent, but maybe
           other people can.
                       MR. WU:  As I said with the feed water,
           the methodologies, we approved the methodology.  So
           they used the methodologies, and we did review their
           detailed calculations.
                       MR. BROWNING:  This is Tony Browning from
           Duane Arnold.  The staff did request a number of
           summaries of the calculations in this area, and they
           were provided to the staff.  
                       And while it wasn't the full set of the
           calculations, it was a fairly detailed summary of the
           calculations that the staff did review.  And
           particularly one of the sets which was requested in
           the last RAI were the cases where we were showing
           ratios in the .98 and .99 range.  So we did provide a
           summary of those calculations to the staff.
                       MR. SHUAIBI:  Dr. Powers, Mohammed Shuaibi
           again.  Would you like us to come back at the full
           committee and address that issue as well?
                       DR. POWERS:  I think what I am going to be
           asking you to do when you come for the full committee
           is to go through a little more discussion of the
           strategy for the review.
                       I think you may be a victim of trying to
           do this expeditiously, in which we posed a set of
           questions here, and you are responding to this
           specific set of questions, and really what we should
           have asked you for was the strategy for the review.
                       But in the course of doing that,
           understanding better where you are taking a
           methodology and asserting, yes, indeed we have
           approved this methodology in the case.  
                       And then the specific thing of how much
           detail you go into in looking at how they apply it,
           might be a useful illustration for people.  And this
           would not be a bad example, simply because it is such
           a striking example.  
                       I think we can progress on to the next
                       DR. FORD:  Are we going to be talking
           about flow induced corrosion and stress corrosion?
                       MS. MOZAFARI:  Right.
                       MR. CARPENTER:  Good morning.  My name is
           Gene Carpenter from the materials engineering branch,
           and I don't have any slides or overheads to give out
                       Basically, the staff had talked to the
           ACRS about the extended power uprate and how we did
           the reviews for boiling water reactors at a previous
           meeting, and to reiterate some of that information,
           the BWR VIP, the BWR vessel internals project, had
           provided a variety of reports for inspections and flow
           evaluations of the safety significant flow of BWR
                       And those include the core spray systems,
           the core plate top guide, standby liquid control, the
           shroud supports, the BWR jet pumps, the LEPC system,
           the lower plenum components, the vessel interior
           diameter attachment welds, various instrument
           penetrations, and the reactor vessel itself.
                       We have reviewed each and every one of
           those inspection or flow evaluation guidelines, and we
           have approved them.  And basically those allow us to
           have some assurance that the BWR licensees -- for
           instance, this licensee -- will be doing adequate
           levels of inspections to ensure that there are no
           degradations that will occur before they will be able
           to see them.  There are no significant degradations. 
           Does that answer your question?
                       DR. FORD:  Well, I have another specific
           item.  All of the VIP reports related to stress
           corrosion cracking, both the disposition and result,
           and inspection period and methods, were based on data
           which was obtained in general with very, very low flow
                       So even below that which are currently
           used in non-power uprated plants.  What would be the
           rationale for saying that they should be necessarily
           applicable to power uprated plants operating at a much
           higher flow rates?
                       When you are doing this evaluation and
           applying the VIP documents, what went through the
           examination process in your mind to say that, yes,
           those VIP documents are applicable to these different
           environmental conditions?
                       MR. CARPENTER:  Well, again, as you
           mentioned here, dealing with the various flow regimes,
           and that is what John was just talking about, with
           flow induced vibrations and he will come back to you
           and talk about that to some greater extent.  So I will
           leave that to his further response.
                       We are obviously looking at the
           chemistries, and as you may remember from your
           previous life prior to the ACRS, BWRs have some fairly
           stringent chemistry controls in place, and even more
           so today than they did even 10 years ago.
                       We were also looking at the overall events
           from a systems point of view.  We also look to some
           extent from the risk management point of view, and
           those are aspects that I will leave aside to others to
           talk about specifically, because I am not a PRA
           expert, per se.
                       But to attempt to answer your question the
           regimes that we have looked at, yes, they were not
           specifically to the power uprated regimes.  But we do
           expect the licensees, when they do these power
           uprates, to take a look at the extended flow regimes
           and see if their applicables, or their usage of the
           VIP reports are going to be maintained so that they
           will stay applicable.
                       CHAIRMAN WALLIS:  Are you speaking about
           vessel internals here?
                       MR. CARPENTER:  Yes.
                       CHAIRMAN WALLIS:  And isn't the flow rate
           the same though with the uprate as it was before?  The
           places where you worry about increased flow are places
           like the dryers and separators, and places where the
           flow really has increased.  
                       MR. CARPENTER:  Right, which is outside
           the safety components that we are looking at.  So the
           basic internal components themselves as I had just
           mentioned, they pretty much --
                       CHAIRMAN WALLIS:  I thought my colleague's
           question was why do you assume that what you did in
           the past is applicable to the future, might be
           answered by saying that there is no change in core
           flow, and so what happens inside the vessel is more or
           less the same as what happened before.
                       DR. FORD:  Thank you for being my straight
           man.  I guess I was questioning -- well, there are two
           things that are changing in the power uprate
           conditions.  The flow rates and/or the flux.
                       CHAIRMAN WALLIS:  That's why distribution
           is changing isn't it?
                       DR. FORD:  Well, the flow rates, and/or
           flux patterns, oth in concert or separately, and in
           effect the cracking susceptibility.
                       The flux to a certain extent is taking
           current or in some of the later VIP documents, but not
           the flow rate.  And so really my question is, is there
           anything that makes you feel good or bad about
           accepting these VIP documents which don't relate to
           the higher flow rates to this particular condition?
                       I have an opinion, but since I have a
           conflict of interest, I can't express it, and so I
           guess I --
                       CHAIRMAN WALLIS:  Well, the question
           really isn't what makes him feel good or bad, but what
           would make us feel better.
                       DR. FORD:  Am I allowed to express my
           personal opinion?
                       MR. BOEHNERT:  I think you probably ought
           to refrain from that.
                       DR. POWERS:  I agree.  You are entirely
           welcome to ask questions, and if it leads us to an
           equivalent opinion, then that's fine.  But I don't
           think you should guide us very much.
                       DR. FORD:  Okay.  I am now hamstrung.
                       MR. CARPENTER:  To rephrase your question
           then --
                       DR. FORD:  There are two things that have
           changed in Duane Arnold as they go into the power
           uprate; flux patterns, and/or flow rate.  Both can
           individually and/or in conjunction affect cracking
           susceptibilities for most of the reactor components.
                       The VIP documents upon which yesterday and
           today we are seeing are saying that we don't have a
           problem with regard to stress corrosion and cracking. 
                       Those VIP documents did not take into
           account changes in flow rate, per se.  In fact, most
           of the data upon which those documents were obtained,
           the disposition curves, are extremely low flow rates.
                       And they don't take into account to any
           great degree changes in flux on the cracking
           susceptibility.  So what makes you feel comfortable
           about accepting their requests for this reactor, which
           is operating in different conditions and which are
           pertinent to the VIP documents?
                       MR. CARPENTER:  Well, I don't think I said
           that there is no problem here.  If I did, I mis-spoke. 
           What the BWR VIP documents give us is some assurance
           that there will be adequate inspections to determine
           if there is cracking before it will progress to a
           point that will be of concern to the staff, and
           obviously to the licensee.  
                       The BWR VIP documents that have been
           reviewed and approved by the staff do specify a flux
           regime, that being less than 8 to the 21 fluence
           levels.  Anything above that is considered a high
           fluence regime and we don't necessarily agree with the
           VIP at that point.
                       We are still in negotiations with with
           regard to BWR VIP regarding what if anything -- what
           additional inspections, if anything, should be
           performed by the licensees.
                       As far as the flow rates, as Dr. Wallis

           said, and as we agreed earlier, we will be coming back
           tomorrow or at a later point to talk further about
           that from a mechanical flow induced vibration point of
           view.  Does that answer your question?
                       DR. FORD:  The applicant took benefit if
           you like from the fact that they are using Noble Chem. 
           How does that come into your evaluation?
                       MR. CARPENTER:  Noble Chem the staff
           considers to be, when used adequately, a definite
           benefit to the water chemistries.  Obviously, it adds
           in the hydrogen and to make use of it, and that
           reduces the crack growth rate by a significant amount.
                       Basically, we have given an order of
           magnitude reduction in crack growth rates for plants
           making use of that.  So that is overall a very good
           thing from our point of view.
                       DR. FORD:  Okay.
                       MR. CARPENTER:  Any other questions? 
           Well, specifically related to the internals.
                       CHAIRMAN WALLIS:  Well, I am a little
           concerned that may be left with an uneasy feeling, and
           I am not quite sure how it is going to go away.
                       MR. CARPENTER:  Which uneasy feeling is
           that, sir?
                       CHAIRMAN WALLIS:  Just the whole way in
           which there have been responses to questions in the
           last hour or so.
                       DR. POWERS:  Well, specifically with
           respect to the inspection frequency, do we have any
           problems with that?
                       CHAIRMAN WALLIS:  Well, it is an
           extrapolation of past experience isn't it?  
                       DR. POWERS:  I am sitting here wondering
           how can I design an inspection frequency that is not
           an extrapolation of past experience?
                       CHAIRMAN WALLIS:  Well, when you are
           uncertain and you presume, then you inspect more.
                       DR. FORD:  Am I allowed to give an
           opinion?  Having put this bomb on the table --
                       CHAIRMAN WALLIS:  Well, you can ask
           questions and hoping that your opinion will appear
           from someone else.
                       DR. POWERS:  Okay.  On this note, I am
           wondering if it wouldn't be appropriate at this point
           to take a break for about -- until 10:30.
                       CHAIRMAN WALLIS:  Okay.
                       DR. POWERS:  We will resume at 10:30
                       (Whereupon, at 10:17 a.m. the meeting was
           recessed and resumed at 10:33 a.m.)
                       DR. POWERS:  Back on the record.  I think
           we have progressed somewhat out of order.  Can we get
           back into the order?
                       MS. MOZAFARI:  What we want to do is just
           finish up on the material degradation issues, and I
           want to briefly give Gene here one more shot at
           addressing your questions, and then we have some
           discussion on stress corrosion cracking or flow
           cracking, the chemistry area for Kris Parczewski, who
           is going to provide that information.  So why don't
           you go ahead.
                       MR. CARPENTER:  And again the question as
           we left before the break was what precisely is the
           staff's level of comfort regarding the BWR-VIP
           documents and why it bounds the extended power uprate
           that Duane Arnold is asking for.
                       And again basically we have reviewed these
           documents to a great deal of level, and Duane Arnold
           is not looking at an increased, or an appreciable
           increase in flow in the area of concern.
                       So the crack growth rates in those areas
           should not significantly increase.  It should not
           increase at all, especially that they are using Noble
                       So the staff has a great deal of comfort
           in this area.  Does that more adequately address the
           question that you had?
                       CHAIRMAN WALLIS:  Yes, it does.
                       MR. CARPENTER:  Any other questions?  If
           not, thank you.  
                       MS. MOZAFARI:  Okay.  Chris, if you want
           to go ahead and come on up.  
                       MR. PARCZEWSKI:  My name is Kris
           Parczewski, and I am from the Materials and Chemical
           Engineering Branch, and I was involved in evaluating
           the degradation of materials due to erosion/corrosion.
                       As you can see on this slide, there are
           several parameters which are or which would affect
           erosion/corrosion, or accelerated corrosion as it is
           now called.
                       Two of them, velocity, which is at the
           bottom here, which affects turbulence, and
           temperature, are going to be affected by power
                       The licensee evaluated this change, and
           came to the conclusion in general that the effect is
           very, very minimal.  The highest effect would be on
           the feed line, and on the main steam line, and those
           changes are going to be taken care of by modifying the
           core input in the code, so that it would predict the
           rate at which erosion/corrosion takes place.
                       And the staff was satisfied that this will
           probably take care of any effect of power outrate.
                       CHAIRMAN WALLIS:  And by the code do you
           mean the CHECWORKS code?
                       MR. PARCZEWSKI:  This is the CHECWORKS
           code developed by EPRI.  
                       CHAIRMAN WALLIS:  I thought there was a
           very good presentation made yesterday on the fact that
           they do a lot of examinations by their
           erosion/corrosion program, and compared it against the
           CHECWORKS predictions.  Did you see those
                       MR. PARCZEWSKI:  The comparison?
                       CHAIRMAN WALLIS:  Yes.
                       MR. PARCZEWSKI:  I looked at them briefly.
                       CHAIRMAN WALLIS:  But you saw them?
                       MR. PARCZEWSKI:  Yes.
                       CHAIRMAN WALLIS:  And can you -- and it
           was also mentioned that other plants have higher flow
           rates than that which Duane Arnold are applying to go
                       MR. PARCZEWSKI:  Yes.
                       CHAIRMAN WALLIS:  Have you seen data from
           other plants which reassures that extrapolating the
           CHECWORKS code is valid?
                       MR. PARCZEWSKI:  No, I did not see that
           data.  However, CHECWORKS was verified against several
           data, and so I trust the code would probably give you
           a proper prediction.
                       CHAIRMAN WALLIS:  I don't doubt that, but
           I think we all have a problem that when you are
           starting to change -- and especially two variables,
           temperature and fluoride, and you are going to
           extrapolate them beyond your database, are you going
           to necessarily going to have a good correlation?
                       MR. PARCZEWSKI:  You see, the CHECWORKS
           code was based on the data from several plants coming
           from this country and from abroad.  So it has a very
           broad database it is based on, and it is being
           continuously updated.  There is a special effort in
           EPRI which updates the data very often.
                       DR. FORD:  But why a database that is
           being used to qualify the code includes conditions of
           temperature and flow rate that we are talking about
                       MR. PARCZEWSKI:  Yes, that's right.  It is
                       CHAIRMAN WALLIS:  How much scatter is
           there in the data?  I mean, do you see a correlation
           through this data?
                       MR. PARCZEWSKI:  Excuse me?
                       CHAIRMAN WALLIS:  Is there a lot of
           scatter in the data around this correlation?
                       MR. PARCZEWSKI:  There is quite a lot of
           scatter, yes.
                       CHAIRMAN WALLIS:  Typically how much?
                       MR. PARCZEWSKI:  I cannot tell you the
           exact number, you know, but there is not one single
                       CHAIRMAN WALLIS:  So you used some average
           curve or upper bound, or what did you use?
                       MR. PARCZEWSKI:  Usually there is a bound,
           upper and lower bound, and obviously it has to be
           within those bounds.
                       CHAIRMAN WALLIS:  Do you mean the mean
           curve as a predictive tool?
                       MR. PARCZEWSKI:  I'm sorry?
                       CHAIRMAN WALLIS:  I am trying to figure
           out how you use -- you said that the data had to be
           between the bounds, and I didn't understand that.  I
           mean, if you have bounds on the correlation, and when
           you take it to the other point, it has to be within
           the bounds?
                       MR. PARCZEWSKI:  Well, it has to be below
           the upper bounds.  
                       CHAIRMAN WALLIS:  And so what do you use
           for licensing purposes?  Do you use the upper bounds,
           or the mean, or what?
                       MR. PARCZEWSKI:  Well, upper bound
           obviously.  It has to be the upper bound.
                       CHAIRMAN WALLIS:  But does CHECWORKS
           predict the upper bound?
                       MR. PARCZEWSKI:  I beg your pardon?
                       CHAIRMAN WALLIS:  Does CHECWORKS predict
           the upper bound or just the mean?
                       MR. PARCZEWSKI:  The means.
                       CHAIRMAN WALLIS:  So how do you figure the
           upper bound into some licensing criteria?
                       MR. PARCZEWSKI:  Well, it is -- I think
           the code is based on the data, and usually it is --
           definitely it predicts below or above the lower bound,
           and obviously to be on the safe side.
                       DR. FORD:  Assume that the CHECWORKS
           prediction code looks like this, and you are saying
           that you have data that is in the upper bounds of the
           data, and the CHECKBOOKS, and that is the two
           questions that we have been asking.  Here is Duane
           Arnold now, and --
                       CHAIRMAN WALLIS:  This is a freshmen
           course in data correlation and interpretation.
                       DR. FORD:  And here is Duane Arnold's
           power uprate.  Our questions have been is the Duane
           Arnold power uprate -- are there other data points
           which codify the CHECWORKS code, and the answer has
           been yes.
                       The next question was when Duane Arnold
           goes to this flow rate, what are they going to base
           their -- what do you approve their basis for their
           inspection in their erosion/corrosion program?  Is it
           based on this value or this value?
                       MR. PARCZEWSKI:  Well, you see, the data
           -- one thing is that the code is being calibrated each
           time, and so all the data from measurement are being
           included in the code.  So it averages all the data
           which are being used for the calibration of the code.
                       DR. FORD:  So it is not an absolute line.
                       CHAIRMAN WALLIS:  That doesn't answer the
                       DR. FORD:  The CHECWORKS is not an
           absolute correlation, which I thought it was.
                       MR. PARCZEWSKI:  No, it has to be
           calibrated.  Usually, you know, you take at least two
           measurements, two sets of measurements, and you add up
           to the code to calibrate so to speak.  
                       And each time you take the measurement,
           and you keep adding to the code, and so the code keeps
           getting more and more precise for a given plant as you
           yield more and more data.
                       CHAIRMAN WALLIS:  Or it might be less
           precise if the data doesn't fit any pattern.
                       MR. SEVERSON:  My name is Russ Severson
           with Duane Arnold, NMC.  Let me try and add a couple
           of things here to try and help clarify a little bit. 
           I think we are getting mixed up between flow rate and
           what has happened, and what the actual corrosion that
           has happened.
                       When you do apply CHECWORKS, and you do a
           corrosion program, you have two things going on at
           once.  One is the model itself, and which is the EPRI
           model, and we have industry and international testing
           that went into the model at different parameters.  
                       And you have your actual inspection data,
           and what CHECWORKS does is that it allows you to
           compare the two to see if your inspection data is
           matching your model, and therefore you have a clear
           understanding of what has previously happened to your
           system, and what will happen.
                       Now, what will happen with what we have
           performed here, and which Kris was trying to allude
           to, we did a parametric study using the CHECWORKS
           model to say, okay, we now believe we have modeled
           these lines fairly well because we have good
           predictions, and so therefore the code is working.  
                       Now, within the code there is bounds of
           with these temperature changes, and the flow rates
           that we are seeing.  So therefore with the code we can
           predict what will happen in these lines.
                       And since we prior could predict with this
           code, then we have very high confidence that we can
           predict in the future.  Now, the temperature change
           really -- and as we showed you before, it is based on
           the solubility of the iron, and the temperature change
           really affects it, and you run the whole gambit of
           that line in feed water in these systems.
                       So all you really do is you change the
           location of where that happens, and so now we are
           having it happen a little bit forward in the feed
           water or in connate than we had before, would be your
           300 degree mark.
                       Whereas, the 300 degree mark would have
           been a different line prior to power uprate, and you
           see those effects.  
                       CHAIRMAN WALLIS:  The other question if
           you are going to use this figure on the board here is
           if you are doing inspections, and you are measuring
           corrosion rate, where did it actually fall in Duane
           Arnold, because this global correlation of data
           doesn't reflect the particular chemistry of a
           particular plant.
                       MR. SEVERSON:  Well, I believe I
           understand your question.  We don't -- go ahead.
                       CHAIRMAN WALLIS:  If you put some
           measurements on that code for Duane Arnold
           measurements where would they be?  I think we are
           saying that we can envision a logical process for
           decision making, but we don't quite understand what
           yours is.
                       We don't quite understand why the staff
           approved it, and that's all, and we can't follow the
                       DR. POWERS:  I think you have adequately
           expressed the challenge that we are facing here. 
           Quite frankly, it looks to me like in many of our
           cases there is an approved methodology that the staff
           has accepted in the past.
                       And the question we are asking is how much
           investigation does the staff do for the application of
           this methodology for this particular application, and
           how did they do it?  And we are having challenges
           understanding that. 
                       MS. MOZAFARI:  So we will just take that
           under advisement.  We will try to provide a basis.
                       CHAIRMAN WALLIS:  I think it is more of a
           generic problem.
                       MS. MOZAFARI:  Right.
                       DR. POWERS:  It is very much a generic
                       MS. MOZAFARI:  Okay.
                       CHAIRMAN WALLIS:  This is a generic
                       DR. FORD:  We are all scientists and we
           are interested in the details.
                       MS. MOZAFARI:  Right.
                       DR. FORD:  And therefore we are asking you
           how did you go through the analysis of these?  I don't
           doubt that it is a good process.  We are just
           interested in how did you do it and we are not
                       MR. PARCZEWSKI:  Basically, we just
           verified the information provided to us, and our
           knowledge of the code, and that is probably a
           satisfactory way to predict the rate at which
           corrosion takes place.
                       MR. SEVERSON:  Kris, I have one more
           thing.  This is Russ Severson again.  I guess the
           point that I was trying to make was that I believe
           that we have validated and we have verified CHECWORKS
                       We know how to employ it at Duane Arnold,
           and we have inspections for it, and we know how to use
           the model to predict these new flow rates.  And the
           fact that oxygen is just as important as flow.  
                       There are many factors here that are just
           as important, and this is just one of them, and I
           believe that at Duane Arnold that we know what
           CHECWORKS is predicting, and we know what our wear
           rates are.  And we have benchmarked the code.
                       MR. PARCZEWSKI:  Basically the problem is
           that it doesn't involve only using predictive code,
           but relies on the actual measurement which is being
           done on the component that is most susceptible to
           erosion/corrosion.  So there is outward verification.
                       DR. KRESS:  How do you use this CHECWORKS
           prediction and in combination with the inspection
           findings to either say your inspection interval is
           okay, or to adjust it?  
                       Are there criteria used to change your
           inspection interval or keep it?  How is your
           inspection interval decided in the first place?
                       MR. SEVERSON:  The inspection interval is
           every outage.  We can't get at these pipes without
           being in an outage because it is hot.
                       DR. KRESS:  That's a pretty good criteria.
                       MR. SEVERSON:  So what we do after an
           outage, and after our inspections, we pull these
           inspections, and we run the CHECWORKS code, and we
           predict what the wear rates will be by the next
                       We decide where we want to inspect to
           further refine the model, and to further refine and
           show that our model is accurate, and what inspections
           we want to do for other reasons, and those are what we
           inspect, and we do that every outage.
                       DR. KRESS:  And the CHECWORKS helps guide
           where to focus your inspections?
                       MR. SEVERSON:  Well, yes.  It gives us the
           feeling of what the wear is in the lines so that we
           can take whatever action that we need to do, that we
           believe that we need to do at that time.
                       CHAIRMAN WALLIS:  And the measurements
           that you make when you do these inspections, do they
           agree with what you expected from CHECWORKS?
                       MR. SEVERSON:  Yes, within what the model
           bounds are.
                       CHAIRMAN WALLIS:  But that is not my
           question.  We don't know how uncertain the model is. 
           If we are going to go with something like the picture
           on the board, I would like to see some red dots or
           something which says this is where we actually are
           when we do our inspections, and this verifies that we
           are close to some mean line or upper bound, or
           whatever it is.
                       MR. SEVERSON:  Well, I tried to push the
           important parts here.  First, as I was saying before,
           in or flow water we have 130 or 140 mils of margin. 
           I am attempting to closely lock in wear rates of
           between 3 and 4 mils per year.  I believe that we have
           an excellent program to know when we are going to have
                       CHAIRMAN WALLIS:  Well, this is the
           problem that we have with lots of SERs, and we have an
           issue raised, and they say read the text, and it says
           we talked with the applicant, and the applicant
           assured us that CHECWORKS was used in some way, and
           this is a standard method.
                       And then it says that the staff finds the
           response acceptable.  We get this all the time, and
           then when we start digging into it, we get into this
           kind of a situation, and we have got to do something
           about that.
                       There has got to be a better rationale for
           the acceptability I think that the staff presents to
           us.  I mean, we can pick on any one of these, and if
           we just pick on a few and we get this kind of
           vagueness, then it doesn't reassure us too much.  
                       DR. POWERS:  I want to move on to another
           issue at this point.  I think we have explored this
           one to the limit of our time availability now.  I
           propose that we go to the PRA analyses and then the
           open issues.
                       MS. MOZAFARI:  There is just one thing
           that I would like to say, and I probably should have
           said it up front.  The staff's review approach -- and
           I think this is what you are trying to get at -- was
           how did they approach the reviews.  
                       They pretty much looked at the ELTR-1 and
           2, and tried to give it the framework of what has been
           accepted in the past, and was it founded in some way
           by what is generically out there.
                       They looked at the Monticello safety
           evaluation, and that provided an indication of how
           deep to go into the review, and were there significant
           differences at Duane Arnold than there were at
                       And then if there were plant specific
           design differences -- and this addresses most all of
           the systems -- they tried to address it in the safety
           evaluation.  If there were not plant specific
           differences, if there was not something very unusual
           about the way Duane Arnold was addressed, then it may
           not have been brought out as something very specific
           and different.
                       So it would have followed the general
           approach at ELTR-1 and 2.  And then the staff made
           several additional requests for information to
           corroborate what was in the supplement and what was in
           the original submittal.
                       And when we needed more information or we
           needed to be sure, you know, from our point of view to
           develop confidence in the staff, it is all documented.
                       DR. POWERS:  The problem is that they are
           not documented.  That when we look at the SER we get
           these vague assurances that the problem was resolved,
           and we don't understand why.  
                       When we discuss it with you, it is not
           evident that you even understand the methodology, let
           alone how it was resolved.  I would like to move on.
                       MS. MOZAFARI:  Okay.  
                       MR. HARRISON:  My name is Donnie Harrison,
           and I am with the PRA Branch in NRR, and I am going to
           try not to repeat everything that was said yesterday
           by the licensee.  
                       I don't think you are going to see a whole
           lot of information that is different from my
           presentation than what Brad Hopkins gave yesterday. 
           The Duane Arnold submittal, as Brenda just indicated,
           followed the ELTR-1, and they provided risk
           information per that. 
                       The staff reviewed internal events,
           external events, shutdown operations, and the PRA
           quality.  Under internal events, I just broke out that
           there is four main areas that we look at; initiating
           event frequencies, component reliability, success
           criteria; and operator actions.
                       Again, most of those topics were covered
           yesterday, and so I am just going to provide what the
           summary results are, and if you want to go into more
           detail, we can.  
                       CHAIRMAN WALLIS:  How do you assess PRA
                       MR. HARRISON:  It becomes a number of
           different factors that are involved.  Basically, you
           are asking a question of does the plant models used in
           the PRA represent the plant that is operating, and in
           this case the plant that is going to be operating at
           extended power uprate.  
                       And so I want to caveat that first with
           how that information is being used.  In this
           application, it is only being used to confirm that
           there is no new vulnerabilities being created, or we
           are not on a cliff edge with our risk, and with this
           uprate, we will fall off the cliff.
                       It is more of a confirmatory analysis, and
           it is not done as a licensing analysis.  With that in
           mind, we looked to see if there has been a peer
           certification done.  We will look and see if there
           were any findings in the IPE and the IPEEE on the
           application's PRA in the past.
                       We will ask questions if we see that there
           is areas that are changing in the plant to see how
           those are modeled in the revised PRA, and so we will
           just confirm that the model does represent the as
           built or is going to be operated plant.
                       So you stole my thunder from my last
           slide.  The first three topics under internal events,
           initiating event frequencies.  The licensee indicated
           that they did not anticipate any changes in
           frequencies of events.
                       I will note that there are changes
           occurring, and modifications occurring to main
           transformers, and the key electrical breakers, to make
           sure that there are operational margin.  
                       The staff considers that as long as the
           equipment is operating within its margin, and within
           its operating limits, that we don't expect the
           frequencies to change.
                       DR. POWERS:  What is the frequency
           dominant accident during normal operation?
                       MR. HARRISON:  I believe it is the loss of
           all site power event, and ATWS -- and I confirmed that
           before here, and ATWS is second on that list, I
                       DR. POWERS:  Can the staff ensure that the
           increase in power is not going to affect grid
                       MR. HARRISON:  The grid stability question
           is typically answered through the electrical branch.
                       DR. POWERS:  But they surely must have
           something packed in the PRA?
                       MR. TREHAN:  This is Nedra Trehan,
           Electrical Engineering Branch.  We do look at
           stability, not in detail, but that stability should 
           be maintained -- with the largest unit on the grid, of
           the nuclear power plant unit, or the most critical
           transmission line.  
                       And we see that those frequencies are
           within acceptable limits, and we do look at stability,
           the general capability curves, whether they are within
           the range, or lighting power factor range that they
           are being operated.  Thank you.
                       DR. POWERS:  And once they have done that
           assessment, how do you translate that into a change or
           no change in the frequency of station blackout?
                       MR. HARRISON:  Well, what we do is we look
           at that as being a no change then in the frequency of
                       DR. POWERS:  No matter what it comes --
                       MR. HARRISON:  As long as it is acceptable
           and it is within its margin, and within its operating
           limits, we at this point assume that the frequency
           will not change.
                       However, there are tracking means, and if
           plant specific data starts to show an increase, then
           that would be reflected in future updates of the PRA
                       And that same logic applies to component
           reliability.  We don't expect any changes in failure
           rates, and there are monitoring programs, and
           maintenance rules, and other types programs, that are
           used to either maintain or to track the failure rates.
                       And at this time we don't see a change
           there.  If one were to start to change in the future,
           it would be reflected in a future update of the PRA.
                       MR. TREHAN:  This is Nedra Trehan. 
           Regarding your question about the frequency.  What we
           are doing with the power uprate is increasing the
           kilowatts, which is calculated into your frequency. 
           If you are increasing the power kilowatt, your
           frequency is in better shape.
                       On the other hand, because KVA or MVA of
           -- if you are increasing the megawatts at the expense
           of -- for that we have to change that station's given
           power reactor, or install capacitor banks to take care
           of the large shortage created by a power uprate.
                       MR. HARRISON:  Okay.  As well, on success
           criteria, we don't expect any change.  The licensee
           reran their -- some map runs to confirm that their
           success criteria as to the power uprate level had not
           changed, and that was the results of that analysis.  
                       The one area that we did see where there
           were impacts were in operator response times.  As
           indicated yesterday, there were five operator actions
           that were identified as potentially having raw values
           of greater than 1.06, which meant that they could have
           a 10 to the minus 6 impact on CDF if they were assumed
           to be filled.
                       And four of those dealt with ATWS and one
           of them dealt with a high pressure transient event. 
           On the ATWS, we broke it down into those four events,
           and they are SLC initiation, and the second one is
           inhibiting ADS if you have high pressure injection
                       The third one is initiation of lowering
           the water level to control power; and the fourth one
           as indicated yesterday was a combination of initiating
           SLC level and lowering power level with turbine bypass
           valves available.
                       On the first one, there was a question on
           timing of the SLC initiation at four minutes, and at
           that, I will pass that on to Dick Eckenrode to just
           provide some information the human factors folks have.
                       MR. ECKENRODE:  My name is Dick Eckenrode,
           and we looked into all five of these events as far as
           the timing was concerned, because in all cases that is
           the key thing, is the time available has been reduced.
                       And the only one that was significant was
           this one, and we compared all five of them to ANSI
           Standard 58-9, which is a rather conservative standard
           in operating timing.
                       The only one that came close was this. 
           This one, the ANSI standard actually said that it
           would have taken about 9 minutes,a nd we should have
           9 minutes.  So they were already less than that with
           a six.
                       And then it had gone to four, and we asked
           a lot of questions of Duane Arnold, and got a lot of
           good answers, one of which is that this particular
           event is one of the critical tasks in the operator
           requalification program.
                       And it is looked at in all of the
           stimulator and a lot of the simulator runs.  The one
           that we had them go back and give us a count of the
           number of times that they have run this.
                       And since 1997 through the present, it has
           been run I think 58 times, with a 100 percent success
           rate.  We felt that this was significant to say that
           they could do it in the time available.  
                       One thing you have to understand is that
           the time was not the critical item here, but
           approaching the byte temperature is the critical
           parameter.  So they weren't really recording times.
                       They were simply looking at the comparison
           of the temperatures, and when the temperature got
           close to the byte line, they initiated SLC.  
                       As far as the actual actions that have to
           be taken, it was estimated by the licensee that it
           really takes about 10 to 15 seconds to perform the
           task.  So we felt that they were well within the
                       MR. HARRISON:  The net result of the
           impacts of the operator actions on the overall CDF and
           LERF for the internal events are shown here as
           increases of 10 to the minus 6 approximately; and just
           a little over 10 to the minus 7 for LERF.

                       DR. POWERS:  These are reiterations of the
           staff's analyses and the products of an independent
                       MR. HARRISON:  Right.  We did not perform
           any analysis to confirm the numbers.  I will note also
           on the upper actions that we did ask the license to go
           back and just look to see if there were a number of
           operator actions just below their criteria for
           screening, which they did.
                       And they came back and only had one event
           that was close, and even with it, it was the recovery
           of river water supply, I believe, and that only had an
           impact of -- if you assumed it filled, it was a seven.
                       And the licensee also went back and
           doubled all their HEP values for things that were
           screened out, and showed that the impact was just a
           little over 10 to the minus 6.  Both of those were
           just used as kind of a sensitivity data to confirm
           that we weren't missing anything.
                       And on the external events, Duane Arnold
           has a seismic and fires were evaluated, and all other
           external events were screened out.
                       CHAIRMAN WALLIS:  Can we go back to that? 
           The doubling -- the use of doubling, is that something
           that was proposed by the licensee, or something that
           you proposed, or was it negotiated?  Could it have
           been a factor of something else?
                       MR. HARRISON:  To be honest, I can't
           remember if we asked them to double, or if they
           provided -- I think they provided the doubling in
           response to a question that we asked them about the
           sensitivity of the results to things that had been
           screened out.  I think that is what happened.
                       And the staff accepted that just as a
           sensitivity, and not as -- again, as a confirmation
           that there was not a lot of actions that can pile up
           together to get you there.
                       On external events, like I said, other
           than seismic and fires, other external events were
           screened out through the EPRI process.  There is no
           direct impacts of the power uprate on earthquakes and
                       And their analysis just shows a path
           through the upper actions that were shown to be
           important, and the internal events pass through these
           external events as well.
                       They did not identify any vulnerabilities
           that were created by the power uprate, and when you
           increase the external events CDF by that, you get an
           increase of 2 to the minus 8, for an overall external
           event probability of 3.7 to the minus 6.
                       And I believe that is all fire if I am
           correct, because they do a seismic margins analysis. 
           So on the seismic area, it is just to ensure that
           there is no vulnerabilities created as part of the
                       DR. POWERS:  Power ampage and more current
           flow, does it change the risk of a switch gear fire?
                       MR. HARRISON:  That would be a component
           failure question again, and I think you would be
           dealing with what is the probability of having an
           event like that.
                       And I don't think you would be able to get
           a good number one way or the other on what that would
           be as a result.  I think conceptually that you are
           right.  You could increase the fire.
                       DR. POWERS:  I honestly don't know.  I
           mean, all I know is that we have the IPEEE insights
           report that tells us which --
                       MR. HARRISON:  And I do know that they did
           a fire analysis at Duane Arnold.  I don't recall what
           was the actual dominant failure modes that resulted in
           the six value.  I am not sure.  
                       And if we move into shutdown operations,
           I think as was indicated yesterday, there is an
           increased decay heat during shutdown operations, and
           so that is going to extend the time where you have two
           pumps that have to be available, RHR decay heat
                       You are going to have reduced times to
           boiling, and therefore you are going to have shorter
           operator response times.  However, for BWRs, typically
           those times are in the matter of hours, and so you
           typically won't impact your operator action human
           error probabilities.  
                       As well, Duane Arnold uses a shutdown risk
           management process, NEMARC 91-06, and they monitor a
           number of different capabilities and features through
           that through an outage.
                       The staff looked at that and determined
           that based on having a risk management approach, and
           based on the fact that you have hours to boiling
           typically, that that was an acceptable risk management
           approach and would be acceptable for a power uprate.
                       DR. POWERS:  Yesterday in our discussion
           of the analysis of human error probabilities,
           primarily connected with normal operations, and not
           the shutdown operations, the speaker acknowledged that
           he did not have expertise in that area, but said that
           they had looked at those probabilities in a variety of
           ways, and he thought that included fires.
                       Did you look specifically at how they
           calculated the human error probabilities?
                       MR. HARRISON:  No, we did not.  If you
           will note, the human error probabilities that they
           were using -- for example, the four minute time window
           for ATWS and SLC initiation, in my view was a
           conservative number.  
                       It is almost 20 percent of the time that
           they are saying that their operators are going to
           fail.  They have got data that supports that they make
           it all the time.  So in looking at that, I see their
           analysis as being conservative, and their numbers tend
           to be that way.  
                       Their human error probabilities that we
           did look at, you weren't down in the 10 to the minus
           4 for operator actions in 15 minutes.  You were
           looking at high 10 to the minus 2s.  And those seem
                       So we didn't look at specific methods, but
           we looked at the reasonableness of the numbers that
           they were producing.  And just to touch on PRA
           quality.  Again, the question is how it is being used
           in this decision making process, and the risk
           information is being used to provide confirmatory
           information, and it is not being used to make the
           ultimate decision.
                       It is just a support tool.  The staff
           looked at the IPE and the IPEEE and safety evaluations
           that were performed, and they did not identify any
           major weaknesses in the Duane Arnold IPEs.
                       Duane Arnold uses their PRA as part of
           assessing hardware changes.  So it is used as part of
           the plant configuration operating process.  And then
           the final thing that we also considered was the fact
           that it was through a BWR Owners' Group peer
           certification process 3 or 4 years ago or so.
                       And those factors we considered in
           determining that we thought that the Duane Arnold PRA
           was acceptable for its use in this application.
           And the last slide just provides a summary that walks
           through each of those areas that we have just
           discussed, and presents just a little bit of results.
                       Their change in CDF and change in LERF
           values are in the small risk increase area for
           internal events.  They are in the very small risk
           increase range for external events.  Again, noting
           that is fires.
                       And they have got a process for shutdown
           operations and the staff found their PRA acceptable
           for this application.
                       DR. POWERS:  I have to say that I am much
           happier with the statement under shutdown operations
           that there is negligible risk, rather than what you
           said on the first or the original slide, which says no
           significant impact.  There certainly is an impact.
                       MR. HARRISON:  Right.
                       DR. POWERS:  There may be no increase in
                       MR. HARRISON:  Right.  There is an
           operational impact.  
                       DR. POWERS:  But there is a very definite
                       MR. HARRISON:  That's true.  I will change
           my slide for next time.  And that is the presentation
           of the PRA.  I would be glad to answer any questions.
                       DR. POWERS:  I would ask this question,
           and you may not be the right one to answer, but I'm
           just curious.  As soon as this power uprate gets
           implemented the IPE for Duane Arnold is no longer
           germane by in large.  Does the staff then go about
           changing the work sheets that the inspectors have for
           the significance determination process?
                       MR. HARRISON:  That is a question that I
           hadn't even thought of.  Do we have any thoughts?
                       DR. POWERS:  You may not be the one to ask
           that question. 
                       MR. RUBIN:  This Mark Rubin from the
           staff.  I can't give you a good answer as to the SDP
           work sheets, but for the maintenance rule
           implementation, certainly their assessment of
           maintenance impacts for assessing the programs have to
           rely on a PRA that is adequate to the task.  
                       And during a maintenance rule follow-up
           inspection, if they were not reflecting that, I think
           they would not be in compliance with the rule
                       DR. POWERS:  One other question that comes
           to mind in that vain is if you look at changes in the
           CDF and changes on LERF, did you look at changes in
           raw and risk reduction worth of components and
                       MR. HARRISON:  Not directly, but just as
           a note, that when the licensee performed their screen
           of what components to look at, they used a raw value
           for components and operator actions.  So there is some
           consideration of that in the process, but it is not
           like you did a raw for including initiating events and
           everything else.
                       DR. POWERS:  Any other questions of the
           PRA work that was done, recognizing again that this is
           supportive and not the basis of the application?  If
           not, I think we can move on to the next subject.
                       MS. MOZAFARI:  You did ask some questions
           about -- you did want us to address grid stability,
           and we do have some members from the electrical branch
           here if you have some specific questions concerning
           grid stability.
                       DR. POWERS:  I thought we had gotten the
           answer earlier.
                       MS. MOZAFARI:  You are happy with that
                       DR. POWERS:  Well, I got the answer.
                       MS. MOZAFARI:  The answer may not have
           been sufficient for what you wanted, but --
                       DR. POWERS:  Well, I understand what you
                       MS. MOZAFARI:  Okay.  Then we will just
           move on.  There were open issues that were indicated
           in the draft safety evaluation.  One of them had to do
           with the start up testing, and the start up testing
           issue, Mohammed Shuaibi has been following it pretty
                       The staff has not come to closure on that
           yet, but it doesn't -- it is not an issue at Duane
           Arnold at this point, and it will be handled in a
           license condition when they get to the point where
           they would trigger the requirement to do start up
                       And by that time we would have made a
           decision on the start up testing with our staff.  It
           doesn't become an issue for Duane Arnold at this
           point.  So this will remain an issue that will be
           addressed when Duane Arnold gets to the power level
           start up testing where needed.
                       And then the other issue had to do with
           MPSH, and Kerry Kavanaugh is going to -- we have a one
           page handout for that to pass around.
                       MS. KAVANAUGH:  I am Kerry Kavanaugh of
           the staff.  As you heard yesterday, it is the
           licensee's position that their licensing basis for the
           use of containment overpressure is based on margin,
           which is 2.7 psig.  
                       And they also stated that when they were
           originally licensed that they were licensed with
           credit for containment overpressure.  The staff agrees
           that they were licensed for use of containment
           overpressure from their original licensing basis.
                       However, the staff does not agree that
           their licensing basis is based on margin.  The staff
           believes that their licensing basis is based on the
           magnitude of the overpressure required and the
           duration of that overpressure as it is required.
                       This was reflected in their original
           response to the staff questions on their MPSH when
           they were licensed.  It was in -- their response was
           a graph that presented the containment pressure versus
           the time, which represented where the pressure was in
           the containment over the accident analysis, along with
           the MPSH requirements during that same time period.
                       This graph was in the Duane Arnold FSAR
           and updated FSAR, up until 2000 when it was changed,
           the figure was changed.  During the years, we believe
           that that graph was the basis for their licensing
                       When we got to this issue, we had quite a
           few discussions on it.  The staff has reviewed in some
           respects their MPSH calculations, and we agree with
           their MPSH analysis for the extended power uprate.  
                       We have sent them a letter, dated
           September 25th, that basically tells them that any
           change that increases the magnitude or the duration of
           the required overpressure than what they are using for
           their extended power uprate would trigger 10 CFR 50.59
           criteria, and would require staff review and approval. 
           That will close the open issue.
                       DR. POWERS:  I guess I understand the
           approach.  Are you telling me that this is an issue
           that will be resolved if I just wait long enough?
                       MS. KAVANAUGH:  Well, unfortunately, we
           couldn't resolve it.  So they removed that figure from
           the graph that we were using as their licensing basis. 
           It is now a containment pressure versus suppression
           pool temperature, which shows that as the pool
           temperature goes up that they will require containment
                       It doesn't tell you how long they are
           going to need it, nor does it tell you how much per
           se, because you really don't know how long they are
           going to be there.  
                       When we discussed containment
           overpressures issues with the ACRS staff 3 or 4 years
           ago, we gave you our approach to resolving the
           increasing number of licensees that were coming in
           needing it, and it was based on this time and
           duration, and an understanding of how much they
                       And we have not had problems with Duane
           Arnold in the past because we had this information on
           the docket.  We don't have that now.  
                       CHAIRMAN WALLIS:  What is the criteria for
           acceptability for this time and duration?  They
           mentioned 2.7 psi required, and they showed us that
           they had much more than that.  They didn't say much
           about time.
                       MS. KAVANAUGH:  They didn't say anything
           about time.
                       CHAIRMAN WALLIS:  Is time the problem
                       MS. KAVANAUGH:  It is very plant specific
           as to what the criteria is.  We have a safety guide,
           Safety Guide 1, that says that you should not be
           granting any containment overpressure  for your break
           LOCA analysis.  
                       However, there is a handful of plants with
           specifically boilers that cannot meet this
           requirement, and they were licensed not meeting the
           safety guide originally and we were aware of this.
                       As time has gone on, there has been
           changes with the plants, and most specifically with
           the BWRs with the strainer issue, and all the BWRs
           have replaced their ECCS strainers.
                       And that has changed their headlocks
           calculations, which is has changed their reliance on
           containment overpressure, along with other
           modifications to the plant.  
                       When plants come in needing credit for
           overpressure, the approach that we have used is that
           we give them what they need, because we haven't found
           any licensees willing to change their pumps out of
           their plants.  
                       So our only opportunity is to evaluate
           their license, approve their analysis, but give them
           what they need and allow some room such that they can
           have some flexibility for operational changes.
                       Some plants need higher amounts of
           overpressure and some don't.  For Duane Arnold,
           because they are going up to 209 degrees, I believe is
           your peak pool temperature, they are going to need
           approximately 5.8 psig, and I don't remember for what
           the time period was, versus two before the EPU.
                       If you look at another plant with higher
           pump requirements, they would be needing a higher
           amount for a lot longer amount of time.
                       CHAIRMAN WALLIS:  Well, I don't quite
           understand your philosophy of giving them what they
           need.  How is this related to public safety?
                       MS. KAVANAUGH:  Well, since we know what
           their analysis is, and we are looking at the risk
           associated and the frequency of having a large break
           LOCA, we know what their analysis is.  
                       And the analysis for the containment
           analysis is generally very conservative.  They use the
           super HEX code.  They use the ANS 5.1 decay heat,
           along with a two sigma margin.
                       Their analysis is done for worst case.  So
           it is generally a very conservative analysis.  There
           really isn't any other way to -- besides changing out
           the pumps, which would be very expensive for them, to
           have them meet this safety guide.  I mean, the --
                       CHAIRMAN WALLIS:  Well, should I feel good
           about that?  It looks as if you -- that when they need
           something, you give it to them, but I don't understand
           the criteria for ever turning them down.  
                       MS. KAVANAUGH:  Well, I don't believe
           there has been a criteria for turning them down.
                       CHAIRMAN WALLIS:  Well, you might as well
           just say we have got a rubber stamp here.
                       MS. KAVANAUGH:  What we do is with a lot
           of care and consideration.  I understand your concern,
           and it has been a hard spot for all of us, but --
                       CHAIRMAN WALLIS:  Is this another case
           where the rationale is fuzzy?
                       MR. SHUAIBI:  This is Mohammed Shuaibi
           again.  We do go back and look at what is available. 
           It's not that we will give them whatever they want. 
           We will go back and look at what is available and make
           sure that it is available.
                       We will look at their containment pressure
           calculations as we did in this case.  So there is
           margin there.  It is not that we will give them what
           they want, and given a situation where their pumps
           aren't going to be able to perform.
                       MS. KAVANAUGH:  I mean, the key assumption
           is that the containment pressure will be there as long
           as you don't lose that containment pressure.  The
           concern is if that containment pressure isn't there.
                       CHAIRMAN WALLIS:  Well, isn't there then
           perhaps a power uprate level where you would stop
           giving them what they need?  If they wanted a 25
           percent power uprate, and then this would give you a
           suppression pool temperature of 215 or something -- I
           mean, there must be some point where you say you can't
           have what you need.
                       MS. KAVANAUGH:  Well, we haven't reached
           that evidently yet.
                       CHAIRMAN WALLIS:  Apparently not.  How do
           you know when you reach it?
                       DR. KRESS:  And where do you decide it
           will be?
                       MS. KAVANAUGH:  No, there is no definition
           as to where it would be.
                       CHAIRMAN WALLIS:  So there is no speed
                       MS. KAVANAUGH:  But our only control is
           reviewing the analysis and then getting staff
           approval.  That is our only mechanism for control.
                       MS. MOZAFARI:  Mohammed, do you want to
           address that?
                       MR. SHUAIBI:  I think clearly that there
           is a speed limit.  I think what your containment is
           able to withstand is a speed limit, although that is
           the extreme.
                       CHAIRMAN WALLIS:  There is no speed limit
           for MPSH per se then?
                       MR. RUBIN:  This is Mark Rubin again, and
           I will just jump in because I think Mr. Hannon has
           already left this meeting.  Clearly, I would only
           point out that the safety guide is a not a regulatory
                       It is a review guideline, and a very old
           one additionally.  I think perhaps what we are being
           told is that the staff's evaluation of the plant
           specific containment analysis is showing that the
           actual pressure that a good analysis shows is well lin
           excess of the extra delta-P that they need for the
           MPSH requirements.
                       And the staff has confidence that the ECCS
           systems will successfully operate because of that
           analytical result, and that public safety is ensured
           because of that.
                       DR. POWERS:  How does that square with the
           single failure requirements for the pumps.
                       MS. KAVANAUGH:  I'm sorry?
                       DR. POWERS:  How does that square with the
           single failure criteria for the pumps?
                       MS. KAVANAUGH:  Well, most plants are not
           licensed to assume a failure of containment along with
           a LOCA.  I mean, that is beyond their design basis.
                       MR. RUBIN:  If you mean a single failure,
           or a single active component failure that would result
           in increased head requirements, I'm sure that is in
           the analysis.
                       MS. KAVANAUGH:  Oh, yes, that is in the
                       DR. POWERS:  All right.  But your answer
           is the one that I was looking for.  
                       MS. KAVANAUGH:  Okay.
                       DR. POWERS:  She got it right.  She knew
           what I was talking about, even if I didn't.
                       CHAIRMAN WALLIS:  I guess I would be more
           reassured if instead of what I heard was give them
           what they need, if there were some kind of an
           explanation like it affords here where you have got
           some kind of prediction that they are making, and this
           is what they need.
                       And then you can explain why it is
           acceptable to be in the region in which they propose
           to be based on some argument which is quantitative and
                       MS. KAVANAUGH:  Well, I mean, I understand
           your concern that they do do a containment analysis. 
           It is a minimum containment analysis.  
                       And they use that as a basis to show now
           much containment pressure they have available.  They
           don't use all that containment pressure.
                       CHAIRMAN WALLIS:  Well, they believe that
           the pumps will operate?
                       MS. KAVANAUGH:  They believe that the
           pumps will operate.  
                       CHAIRMAN WALLIS:  And what is your basis
           for believing the pumps will operate?
                       MR. SHUAIBI:  I think in this case -- and
           this is Mohammed Shuaibi again -- that we did
           confirmatory analysis in this case --
                       MS. KAVANAUGH:  For the containment.
                       MR. SHUAIBI:  -- confirmatory containment
           analysis for this case, and we are comfortable with
           their values on the pressure that is involved in
           containment for the scenarios.  Unfortunately, we
           don't have the lead reviewer for that here, and that
           is what we offered earlier, that he could comment to
           the full committee and talk about those independent
           analyses that we did.
                       DR. POWERS:  From a historical point of
           view, let me see if my understanding -- and you can
           feel free to correct me if my historical perception in
           this area is inaccurate.  
                       When we originally licensed these plants,
           credit was given for overpressure for MPSH because of
           the physical fact that it was running and intact, and
           the coolant loses its density because of its elevated
           temperature if there was going to be containment
                       That in recent years, we became less
           confident in that as a safety margin, and we
           questioned whether that overpressure was appropriate
           to grant overpressure.  
                       And there are some plants that are
           licensed to use the containment overpressure.  That is
           an irreversibly fact of life, but we are nervous when
           we grant these things.
                       MS. KAVANAUGH:  We are getting nervous
           because they are requiring more.  If you look at the
           original analyses, it was a pound here, and less than
           a pound.  Now we are getting into time periods where
           they are needing 5 or 6 pounds for several hours.
                       MS. KAVANAUGH:  So, yes, that is where the
           level of uncomfortable comes from.  
                       DR. SCHROCK:  What is the basis of the
           confirmatory containment analysis?  What method is
                       MS. KAVANAUGH:  I did not do that
           analysis.  That is something that we can discuss
           tomorrow, but I believe they used the contain program.
                       DR. SCHROCK:  I am not going to be here
                       CHAIRMAN WALLIS:  There is no tomorrow.  
                       MS. KAVANAUGH:  Oh, okay.
                       MR. SHUAIBI:  Again, the lead reviewer on
           this is not here, but we can discuss that at the full
           committee meeting.  We offered to do that.
                       DR. SCHROCK:  I won't be there either.
                       MS. KAVANAUGH:  But I believe they used
           the contain program as -- do you remember?  You're no
           help -- the confirmatory analysis code.
                       MR. BROWNING:  This is Tony Browning from
           Duane Arnold again.  The staff was using the contain
           code, and requested a great deal of data from us so he
           could benchmark his model to our containment design
           and specific parameters so that he could do the
           confirmatory analysis.  So that is how it was
                       DR. POWERS:  Any other questions?
                       CHAIRMAN WALLIS:  Well, if these plants
           don't meet the guidelines, maybe what you need is a
           new set of guidelines which logically explain a change
           in position, and explain the rationale for giving
           credit for these overpressures.
                       MS. KAVANAUGH:  That is a good point.
                       CHAIRMAN WALLIS:  And then set some limits
           to what is acceptable based on some criterion, which
           might even be related to risk or something that we can
           grasp a hold of.
                       Would it be unreasonable that you
           recommend that you rewrite the guideline to be more
           specific, and explicit, and rational?
                       MS. KAVANAUGH:  I believe at one point 
           -- and I don't remember specifically, but I believe it
           is Reg Guide 182, that also deals with MPSH analysis.
                       And there was an effort at one time to
           combine the safety guide in with that, because that
           deals with vortexing and all kinds of fun stuff, and
           into one reg guide which would explain that.  But I
           don't know where the staff's effort is on that
           initiative or not.
                       MR. BOEHNERT:  How many plants are
           affected by this?
                       MS. KAVANAUGH:  I would say we have 2 or
           3 PWRs, which are multiple unit sites; and I would say
           about 12 BWR sites.  You will find that the newer
           units don't run into this problem.  Their MPSH
           requirements on their pumps are extremely low.
                       DR. POWERS:  Thank you.
                       MS. MOZAFARI:  By way of concluding, I
           just wanted to reiterate a little bit that the staff
           used the ELTR-1 and 2 as the framework for the review. 
           It was more or less the outline that they followed to
           see that everything got addressed.
                       They used the Monticello safety evaluation
           more or less as a template to kind of scope the depth
           of the reviews.  Plant specific design differences
           were addressed, and that's why you ended up with a
           foot of documents.
                       Usually it was the back and forth of
           questions that the staff asked Duane Arnold
           specifically about their design and submittals.  And
           then these were followed up by follow-ups from
           telephone conferences that supported the staff
           reviews, and documented by the information requests.
                       This pretty much lays out the scope of the
           review, and it is consistent with the ELTR-1 and 2,
           and the way it was provided, and it pretty much does
           address all areas.  
                       Further guidance on review is provided by
           the SRPs in the different systems areas.  And they did
           follow their SRPs.  And this states what the staff has
           concluded in the draft safety evaluation, and will be
           seen again in the safety evaluation, that all areas
           affected by the extended power uprate have been
           reviewed and evaluated.
                       And all the methodologies used for
           extended power uprate analyses are acceptable to this
           staff for this application; and the results of the
           analyses were acceptable, and there were cases as we
           have indicated where we did confirmatory analysis.
                       The PRA results showed an acceptably small
           increase in risk associated with the extended power
           uprate, and therefore the proposed extended power
           uprate of 15.3 above CRTP, which is 20 percent above
           the original license power level is accepted for Duane
           Arnold.  Are there any other questions?
                       DR. POWERS:  Well, thank you.  What I
           would like now is to move to a discussion with the
           committee to discuss what we want to present --
                       MR. SHUAIBI:  Dr. Powers, Mohammed Shuaibi
           again.  There were a couple of questions that came up
           earlier, I believe, that you wanted to talk about,
           namely grid stability and something with containment
           hydrogen and questions that came up about that.  We
           have people here to address those questions if you
                       DR. POWERS:  I think we got the answer on
           the grid stability.
                       CHAIRMAN WALLIS:  And that the oxygen
           didn't meet the requirements, but somehow or other
           that was acceptable for some reason.  Was that the one
           that you were mentioning; the 5 percent oxygen
                       We were told that they didn't meet the
           requirements at the start of the event, but for some
           reason this was judged to be okay because it was not
           a time where you really needed to worry about the
           issue or something.  
                       It was a reassurance that the staff has
           good rationale for allowing the licensee not to meet
           requirements.  That's all.
                       MR. PERALTA:  This is Jim Peralta from the
           Plant Systems Branch.  There is a period of
           approximately 24 hours where after the LOCA where the
           hydrogen monitors would not operate as accurately as
           they are supposed to.  
                       The licensee has stated that they in fact
           will be indicating somewhat high, which would be a
           conservative direction, and it is essentially on that
           basis that we accepted it.
                       CHAIRMAN WALLIS:  So it would seem that
           they would meet the requirements if they overestimate
           something and then they are conservative, and then
           they are essentially meeting the requirements; is that
                       MR. PERALTA:  Yes.
                       CHAIRMAN WALLIS:  Were there requirements
           written in some way that doesn't reflect this ability
           to be conservative?
                       MR. PERALTA:  The point was that the
           instrument wouldn't be working as it was originally
           intended to work because it would be outside of its
           deign parameters.  However, it would be indicating in
           a conservative direction, yes.
                       DR. POWERS:  And were certain that nothing
           irreversible happens to this device?
                       MR. PERALTA:  Well, I don't know that we
           asked them that specifically, but that certainly is
           implicit in -- well, they said after that period of
           time that it would begin operating within its design
           parameters.  That it would go back to operating within
           its design parameters.
                       CHAIRMAN WALLIS:  To monitoring hydrogen?
                       MR. PERALTA:  Yes.
                       CHAIRMAN WALLIS:  And there was a five
           percent oxygen requirement that you are trying to
           verify, or is that something else?
                       MR. PERALTA:  As far as I know, it is the
           hydrogen monitoring.  I didn't see anything on oxygen.
                       CHAIRMAN WALLIS:  That they monitored
           oxygen, and that they reached the 02 limit one day
           earlier without the power uprate.  Maybe this also
           needs come clarification.  Perhaps again we could have
           something written to the subcommittee so we can look
           at it before we have to go before the full committee.
                       MR. BROWNING:  Excuse me, Dr. Wallis. 
           This is Tony Browning from Duane Arnold again.  These
           are combined monitors.  They monitor both oxygen and
           the hydrogen content in the containment.  So you are
           monitoring both.
                       CHAIRMAN WALLIS:  They are conservative
           about oxygen or hydrogen, or both? 
                       MR. HUEBSCH:  This is Steve Huebsch from
           Duane Arnold.  They are conservative when the
           containment temperatures are higher than the heat
           trace temperature, and the analyzers are conservative
           for both.  
                       The issue that comes up then is the fact
           that if they aren't within their accuracy bounds for
           the Reg Guide 197 criteria, the operators could
           perform an action prior to needed.
                       That was part of the discussion early on. 
           So if they were reading your five percent oxygen level
           at a point where --
                       DR. KRESS:  It is really 3 percent.
                       MR. HUEBSCH:  Yes, and if it is only 3
           percent, the operators might be in a situation where
           they would attempt to perform compensatory actions to
           deal with high levels of oxygen/hydrogen.  
                       So one of the things that we have
           identified is that when you get into the EOPs and
           start looking at the event that you are talking about
           2-1/2 days, or 2.3 days by the analysis, before you
           would ever get to the situation, and that is via a
           conservative calculation.
                       What we can do with the analyzers is even
           though the temperatures caused this over prediction in
           the analyzers, or a slight over- prediction when they
           get down close to the heat trace temperatures, they
           still do trend.
                       So the operators can watch a trend in
           increasing levels over time for the first 24 hours,
           and they will be able to tell where their
           hydrogen/oxygen levels are leading.
                       We have also got calculations that we have
           had in the past that compensate for those.  We don't
           have those calculations currently in our operating
           instructions because when we installed the heat trace,
           we took those out.  
                       The one thing that we are looking at now
           is we are saying that we have the ability to trend the
           hydrogen/oxygen levels.  They will be a little over-
           predictive until the containment temperatures drop
           within the band of the heat trace.
                       And the calculations show that that will
           occur within the first 24 hours, and the conditions
           won't affect the analyzers adversely.  
                       So once the 24 hours period comes down the
           operator can look over, and in essence what we have
           done in the EOPs is that he can look at the
           temperatures in the containment, and make the
           assessment of the accuracy of the --
                       CHAIRMAN WALLIS:  But the argument is no
           longer that they are conservative because they are
           reading high.  It's whether or not they mislead the
           operators because they are reading too high, and then
           you are going to have to have proper operator training
           to not be mislead by this reading, which is due to the
           fact that you put a heat source close to the sensors.
                       MR. HUEBSCH:  They have already had the
           training as part of the operation.
                       CHAIRMAN WALLIS:  So this is acceptable
           because the staff accepts that the operators will
           still take the right actions because they will know to
           not misunderstand these faulty readings.  Is that the
           way the staff resolves it?  That wasn't the
           explanation that we got first.
                       DR. KRESS:  Well, if the operators take
           the action that was intended at the wrong time, it
           still would be an effective action, and the safety
           issue is a question of if you guys don't want to mess
           up your operations by having them do it when they
           didn't have to.  Wouldn't that be a better way to
           characterize it?
                       MR. HUEBSCH:  Yes.  Their compensation
           would be to inject --
                       DR. KRESS:  So if they did make an error,
           it's not a fatal error.
                       MR. HUEBSCH:  No.  You would inject the
           CAD, and you would add a nitrogen mask to the
           containment, and still stay within the pressure limits
           because the system was designed that way.  You would
           mitigate it with a change of time sequence for events.
                       DR. KRESS:  Yes.
                       CHAIRMAN WALLIS:  Well, maybe what is
           indicated here is that this was a draft SER, and when
           you write about oxygen and hydrogen that it will be
           clarified in the final SER.  
                       Now, what is the procedure then?  Do we
           actually have to look at the final SER?
                       MS. MOZAFARI:  We are in the process of
           getting the final SER done, and you would see the
           final SER, but I believe that what we are looking for
           is that any questions that you refer to us, we will
           evaluate those in concert with the final SER.
                       CHAIRMAN WALLIS:  I am wondering if we
           should have a full committee meeting before we have
           this final SER?  We have had this debate before, where
           there was something about the SER that we were unhappy
           about, and then something got approved, and before we
           got to approve something that was in draft form, with
           the assurance that something would be fixed.  I wonder
           if that is the appropriate way for us to act.
                       MS. MOZAFARI:  Well, we would expect to
           get your comments, but I think that some of the issues
           that you were commenting on we were planning to
           present at the full committee anyway, and we would
           incorporate any suggestions into the final safety
           evaluation, and so they would be addressed.
                       DR. POWERS:  Well, how much time has the
           committee allocated for this?
                       MR. BOEHNERT:  We have -- let's see, about
           an hour-and-a-half, from 8:35 to 10:15 on October 4th.
                       MR. SHUAIBI:  I guess that question is to
           the ACRS, but what I would offer is if we can provide
           you written responses to those questions that you
           have, and provide you an explanation of our review
           process at the full committee.  We would rather do it
           that way, but obviously it is up to you.  
                       DR. POWERS:  I would like to talk to the
           members now about what they would like to see the
           staff and the licensee present, and I would begin with
           the licensee.  
                       My personal bias is that we ask the
           licensee to give a fairly summary discussion of what
           he has done to change his plant and then to present
           his PRA results, perhaps with even a little more
           detail on the work that he has done on human
           reliability, and also some human error analysis,
           because I think my rationale for doing that is that
           that gives him this summary opportunity to speak to
           the committee, in terms of the language which it
           likes, which is risk. 
                       I think he has done some things that I
           think are innovative there.  At the same time, he
           needs to give a summary of the things that he needs to
           change in his plant, which look to me to be fairly
                       DR. KRESS:  I agree with what you say,
           Dana, with one exception.  I think the power uprate is
           being reviewed on the basis of compliance with the
                       DR. POWERS:  It is.
                       DR. KRESS:  I think the committee would
           want to and would need to hear how they -- the story
           about how they are complying with the various limits
           that they have to meet for the power uprate.  So I
           would have what you said, but I would want to see a
           summary version of the compliance also.
                       CHAIRMAN WALLIS:  We need to hear more
           about ATWS don't we in the full committee?  That seems
           to be one of the compliance areas. 
                       DR. POWERS:  Well, my thinking with regard
           to the ATWS -- or at least what I was thinking of --
           well, Tom is right.  This is a compliance application
           and what not.  
                       Quite frankly, the licensee is electing to
           deal with ATWS in a way that we have already seen.  He
           is not introducing a great deal of innovation.  He is
           following a plan that has been developed by GE, and if
           memory serves, we discussed at length.
                       There are some subtleties to it that I
           don't really fully understand that we could go into,
           but I thought it would be better to go into those
           compliance issues with the staff.  
                       I think we have to make a decision on what
           we would do here, because given the amount of time --
                       DR. KRESS:  We don't have a lot of time,
           that's for sure.
                       DR. POWERS:  And what I don't want to do
           is get the licensee and the applicant into a position
           of having to give such a summary presentation that all
           he does is everybody sits around and -- that the full
           committee just gets confused, because they haven't all
           seen this.
                       DR. KRESS:  I think the plant changes and
           the PRA summary both go pretty fast.  
                       DR. POWERS:  I think we need to decide 
           -- well, the way they handled the PRA in the
           presentation to the subcommittee was a fairly lengthy
           package, but a short terse presentation as befits its
                       If we wanted to keep it that way, then I
           think it is no more than a view graph showing the
           bottom line results, and not any greater discussion on
                       DR. KRESS:  I think the view graphs that
           show what led to the bottom line results have a few of
           them, but mostly human error is based on the human
           error changes, and is based on the timing.  I think
           those would also be appropriate to have in there,
           because that is the whole basis for the changes.
                       And this discussion on the use of
           compliance for the events, I think that belongs or
           could be part of it.
                       DR. POWERS:  So what you are basically
           saying is that you would like to see a summary of
           everything that was presented?
                       DR. KRESS:  Well, no.  They went through
           a great deal of trouble to answer all the ACRS
           questions that we put to them ahead of time.  I don't
           really think we need to go through those again.  
                       I think they just give the slides to them
           or something, and let the rest of the committee read
           them.  But I don't see how we can avoid going through
           the compliance part of it.
                       DR. POWERS:  I wasn't going to avoid that. 
           I was going to go through that with the staff.  
                       DR. KRESS:  Oh.  Well, that may be, but I
           don't know if the full committee will be pleased with
           just saying that they did all the calculations using
           approved codes and met the limits.
                       DR. POWERS:  Well, I think we have to give
           them something fairly specific.  I don't think we can
           say give us a summary and then come back and say,
           well, that wasn't enough detail.  That just is not
           playing fair.
                       So let's talk through the topics that were
           presented and say do we want to hear about that or
                       DR. KRESS:  Okay.
                       DR. POWERS:  Okay.  They have compliance
           with regulatory requirements, and they have hardware
           modifications, analyses performed, and impact on plant
                       DR. KRESS:  I think I want to hear those
           and the whole basis of that.
                       CHAIRMAN WALLIS:  That is the whole basis
           for the decision.
                       DR. POWERS:  If they are going to go
           through it, then we are going to hear it again from
           the staff.  That's the thing that I was trying to
                       CHAIRMAN WALLIS:  Well, they went through
           that fairly briefly.
                       DR. POWERS:  All right.  We have plant
           operator training, stability monitor/instability
                       DR. KRESS:  I think I can do without both
                       CHAIRMAN WALLIS:  What we really need to
           do is the stability if you want to show anything at
           all.  There is orange curves and that you can actually
           get up past them, and things --
                       DR. KRESS:  Yes.
                       DR. POWERS:  Okay.  So we want to go
           through that.  ATWS event response for uprate
                       CHAIRMAN WALLIS:  I am tempted to ask the
           staff why they accepted the ATWS response, but that
           may take a long time.
                       DR. POWERS:  You are going to get that
                       CHAIRMAN WALLIS:  We don't need to go
           through all the details of that.
                       DR. POWERS:  Well, I think it is do they
           go into it or not.  There is nothing detailed in the
           45 minutes that I am going to give them.  I mean, we
           have got an hour-and-a-half.
                       CHAIRMAN WALLIS:  Well, I think we have to
           have something about ATWS, because ATWS is going to
           turn out to be the power influences to the PRA later
           on isn't it?  So I think you have to say something to
           that before --
                       DR. POWERS:  Graham, I understand what the
           problem is, but they have got 45 minutes, and so that
           means they get 23 minutes to talk.  That means that
           they get one view graph on each one of these topics,
           or we yell at the planning and procedures, because
           they have only give us an hour-and-a-half here.
                       DR. KRESS:  I think that is where the
           problem is.
                       CHAIRMAN WALLIS:  Well, I think you have
           to say that ATWS was handled in the standard way, and
           what has changed here is that the operators have to
           respond quicker.  That's what they have to say.  Can't
           they say that quickly?
                       DR. POWERS:  No, because someone like you
           will ask them something that they don't feel obligated
           to answer.  
                       CHAIRMAN WALLIS:  It won't be me, but I
           know who it might be.
                       DR. POWERS:  But there are committee
           members who have been known to ask questions at least
           as detailed as yours.  Okay.  Is there any topic on
           here that they don't need to go into?
                       DR. FORD:  You could argue that materials
           degradation -- if you are talking about the time
           available, materials degradation issues, I have got my
           own opinion as to how important they are or not.  
                       And I have put myself in the position of
           your technically informed person out in the public,
           and how they would react to presentations given today,
           in terms of the amount of quantitative data from the
           assessment on material degradation issues.  Dana, I
           don't know if those minutia should be covered in the
           full committee meeting.  I would suspect not, but I
           would hate to see our recommendations not taken
           account of.
                       DR. POWERS:  We will get to draft a letter
           and provide the committee with a summary.  I can't
           imagine your esteemed colleague from Oregon sitting
           quietly and having been drugged through the details of
           ATWS response not getting at least a chance to hear
           the word CHECWORKS.
                       So if you are going to go into this
           detail, we are going to do it twice; once with the
           licensee and once with the staff, and we had better
           cover them all.
                       I would hope they would not have to go
           through the discussion with the dryers and the
           separators.  They are not safety issues, and nothing
           emerged out of this that suggests that that would
           change.  But that is the only one so far that I have
           been able to take off this list.
                       I mean, what you are saying is that you
           would like to see a compact version of this, the
           presentation that they prepared for us yesterday
                       DR. FORD:  Apart from the dryers and
           separators, which I agree with you, the safety issue
           is the question of the quantitative treatment of the
           VIP vibration criteria for stress corrosion and
                       The details of the FIV, which I personally
           don't believe is a big problem, but as presented,
           somebody could turn around and say it is not
           adequately supported in the information given.  And
           the other one is the one that you brought up, the CUF
           factors, and why are some up and some down.  What is
           the rationale.
                       I personally don't think that these are
           big deals.  But to someone outside this room, you
           don't see any evidence that they are a big deal.  Do
           you understand my point?  In what venue do you sort
           these things out and do you record preservation of
                       DR. POWERS:  Right now I am only trying to
           give guidance to the licensee on what he is going to
           have to present.  We have given him no help whatsoever
           because all we have said is that we want to hear four
           hours of presentation in 23 minutes.  
                       And I don't think he is going to dance at
           his daughter's wedding over this one.  
                       DR. FORD:  I am quite willing to put my
           hand up and say don't mention it given the time, and
           I don't think there is any need to have a big
           discussion on materials degradation.
                       But I would hate to see it in the public
           environment, where this is not enough sufficient
           quantity for discussion.
                       DR. POWERS:  Well, there are multiple
           things that go out on a public venue, and the staff
           evaluation report is a public document, and does go
           into this subject.
                       DR. FORD:  But is it worthwhile for me
           just to write down my comments here and give them to
           the staff?  Is that good enough?
                       DR. POWERS:  There is another public
           document, and that is the ACRS letter, and I am not
           sure who it goes to right now.  There are multiple
           avenues for bringing this up.
                       It appears to me that the recommendation
           of this subcommittee to the licensee on what he
           presents -- and understand that the licensee can use
           his own good judgment on what ought to be presented --
           is that you attempt to go through the Items 1, 2, 3,
           and 4 in the agenda, and 5.
                       And I would suggest that in light of the
           time limitations that you not go into the PRA results. 
           It is not part of their application.  It is going to
           provoke a lot of discussion, and you haven't got time
           available to you to cover it in a way that you will
           find satisfactory the items that are being presented
           to you.
                       And Dr. Ford has suggested that you can
           limit the amount of discussion that you do on the
           corrosion substantially.  I think the committee has
           been through CHECWORKS as an entity in some detail in
           the past, and those that have an interest in it have
           all been through it fairly in detail.
                       I think if you want to approach the
           subject, it is adequate to say that you looked at flow
           erosion using the CHECWORKS methodology, and let it go
           at that.  
                       Otherwise, it sounds like most of these
           things they want to address.
                       MR. MCGEE:  Could I review the list once?
                       DR. POWERS:  You certainly can.
                       MR. MCGEE:  This is Ron McGee.  So you are
           requesting that we would cover next week during the 23
           minutes allotted --
                       DR. POWERS:  You will have 45 minutes and
           we usually count that in 45 minutes that we have had
           quite a cross-section of the committee here.  So you
           might shade that a little bit, and take a little more
                       MR. MCGEE:  Thank you.  So, the plant
           modifications and then regulatory compliance, and the
           analysis performed, operator training, thermal-
           hydraulic stability, the ATWS response, fuel response
           for ATWS instability, and material degradation --
                       DR. POWERS:  I think that you can handle
           that with one sentence there.  If somebody else had a
           question, I think that can be pretty promptly handled
           because you are using fairly standard methodologies
           here, or that are familiar to the rest of the
           committee.  There is nothing ground breaking in this.
                       MR. MCGEE:  Okay.  Our containment
                       CHAIRMAN WALLIS:  I think you would have
           to show your justification for your MPSH.  I think you
           have one summary curve that shows the containment
           pressure and the pressure required, et cetera.  It has
           been an issue, and it is something that the staff has
           raised.  So you have to make your case for that.
                       MR. MCGEE:  We can skip the steam dryer
           and separators.
                       DR. POWERS:  I think you can.
                       MR. MCGEE:  ECCS analyses.
                       CHAIRMAN WALLIS:  That's the bottom line. 
           I think you need to have a bottom line; that of the
           1300 and something degrees.  You need to reassure that
           you will meet the criteria.
                       DR. POWERS:  Yes, and I would approach
           that with a little caution, and make it clear that you
           have two limits, and why you have two limits, and why
           you comply with both of them, just because that is
           new.  And you can go on to say that the second one may
           actually evaporate one of these days or something.
                       CHAIRMAN WALLIS:  Now, why is he skipping
                       DR. KRESS:  Don't have the time.
                       CHAIRMAN WALLIS:  I think he has to show
           the PRA bottom line.  I think you have to show the
           bottom line on any issue that is significant.  
                       DR. POWERS:  Graham, I know something
           about some of the members of the committee, and if we
           ask them to show a bottom line on the PRA, those
           members of the committee will say a bottom line isn't
           good enough for me.
                       CHAIRMAN WALLIS:  Then we are going to
           need to have more time.  This is the place where the
           licensee makes the case in a public forum that an
           uprate should be granted, and it has got to be a fair,
           comprehensive case.  It doesn't have to be detailed,
           but it has got to cover main arguments.
                       DR. POWERS:  The PRA is not part of the
                       CHAIRMAN WALLIS:  Well, it is a
           consideration, and I think the conclusions here are
           kind of similar.  
                       DR. POWERS:  I feel a responsibility to
           comply with what the planning and procedures have
           given me for time, and I am afraid that if just giving
           a bottom line on the PRA is --
                       CHAIRMAN WALLIS:  It is going to be asked
           anyway.  It's not going to be asked for anyway?
                       DR. POWERS:  And that is the other thing. 
           Remember, I came in here with a going in position of
           just doing the PRA.
                       CHAIRMAN WALLIS:  And that's why I
           wondered why you flipped completely.
                       DR. POWERS:  Because I can't ask them to
           do everything in 23 minutes.
                       CHAIRMAN WALLIS:  Then they need more
                       DR. POWERS:  I could ask them to do
           everything if I gave them the whole morning.  I would
           keep my PRA results in my pocket, and just hit them
           with the bottom line numbers on it.  And if it is
           provocative, I will take the time out of Wallis' hide.
                       CHAIRMAN WALLIS:  I have a topic that we
           can vote on in five minutes.  
                       DR. POWERS:  What did you say?
                       CHAIRMAN WALLIS:  I am very happy to take
           some time out of my topic.
                       DR. POWERS:  I think you have done -- I
           actually think you have done some innovative things
           with the PRA that would be of interest to the
                       MR. MCGEE:  The information that we
           provided yesterday, all the slides and stuff, will
           that be provided to the full committee prior to our
           meeting with them?
                       DR. POWERS:  That would ordinarily not be
           the case.  They could get it if they asked for it. 
           But that would not ordinarily be the case that they
           would have it.
                       DR. KRESS:  Quite often we have had people
           come in with a package like that and say we are not
           going to present this, but if you would like to read
           these, here is a group of slides that tells you.
                       DR. POWERS:  And as I said, I think you
           have done some innovative things with your PRA that I
           wouldn't be stunned if you advertised it.  I think you
           have done an evaluation and in screening your human
           performance issues using PRAs to identify things.
                       And I think what you did for screening of
           components that is in your PRA was an innovative act
           in your application.  I would have enjoyed exploring
           with you just to see how you did it and whether it was
           useful, and whether you would ever do it again.
                       But I think you have time to perhaps
           discuss that with individual members if they ask
           questions, and you may be able to present the bottom
           line numbers and what not.
                       The trouble is that this committee -- the
           full ACRS committee, their eyes tear over and they put
           hands on their heart when the word PRA comes up, and
           they have more questions than most people would ever
           be able to generate answers.
                       And here we are focusing more on power
           uprate issues, which of course you are doing
           innovative things there, too.  Now, I would like to
           come to the staff presentation at this meeting.  
                       And I will begin again with my suggestion
           to the committee, and see if they will overrule me,
           just as efficaciously as they did with respect to the
                       It seems to me that opposing sets of
           questions for the subcommittee meeting, in the
           interest of efficiency, we may have sandbagged the
           staff a little bit.  And that we need to give them
           more freedom to design their presentation.
                       And I would encourage them to design their
           presentation to dissuade the committee from writing a
           letter that begins, "With the ACRS unable to ascertain
           if the staff has done an adequate review of the Duane
           Arnold application for a power uprate.  Our
           examination of the SER suggests the staff has asked
           perceptive, probing questions.  Documentation of the
           resolution of these questions in the SER is quite
           limited has become the familiar pattern for SERs."
                       "Our discussions with the staff did not
           produce satisfactory amplification of the SER.  Too
           often the staff appears to have accepted a methodology
           that has been proven in the past without showing that
           it has also done an adequate investigation into the
           application of the approved methods."
                       "After oral discussion with the staff, it
           is not apparent that the staff is adequately familiar
           with either the methods or the specific application."
                       I think that I would like the staff to 
           make a presentation that forecloses writing that kind
           of a letter.
                       CHAIRMAN WALLIS:  In 45 minutes.
                       DR. POWERS:  In 45 minutes.
                       CHAIRMAN WALLIS:  With questions.
                       DR. POWERS:  With questions.  I think the
           areas that the subcommittee has pursued in here give
           you some guidance to what we are looking for when we
           say have you done an adequate application or
           investigation on how it was applied to the specific
           issue here.
                       I think we are in general familiar with
           those approaches that the staff has accepted in the
           past, and it is really how they were applied that is
           at issue here.  
                       And as I said, when I read the SER, I
           found -- my general impression in reading the SER were
           the questions that the staff was asking were the right
           questions.  In fact, they were very good.
                       It's that their final resolution doesn't
           come through as clear and clarifying.  I am giving you
           my personal viewpoint, and I will turn to the rest of
           the committee and see what they would like to hear
           from the staff.
                       DR. KRESS:  Personally, I will bite off
           from what you said.  That would have been my
                       DR. POWERS:  Professor Wallis, have you
           any guidance that would like to give the staff on
           their presentation?
                       CHAIRMAN WALLIS:  Well, I think you have
           given them a challenge.  I'm just wondering how they
           will respond to it.  I guess I will just have to wait
           and see.
                       DR. POWERS:  I remain confident that they
           can, because again I looked at the SER, and I looked
           at the kinds of questions that were being asked, and
           addressed, and I thought that they were perceptive and
           challenging questions.
                       CHAIRMAN WALLIS:  The only thing that I
           worry about is the committee getting into some of the
           morass that we got into; is that when we start probing
           the rationale for the decisions, we have difficulty
           getting answers to the questions posed.  I don't want
           that to happen with the full committee.  The answer
           should be crisp and to the point and reassuring.
                       DR. POWERS:  Professor Schrock, can you
           give us some help here? 
                       DR. SCHROCK:  Probably not.  I have been
           concerned for a long time about this issue of the
           falling back on the fact that analyses are done in
           accordance with previous approvals, and frequently
           that gets in the way of communicating an understanding
           of what is done and how it is applied in the present
           situation.  I think you have said that very well.
                       And I am glad to hear that challenge
           thrown up to the staff.  I think that is something
           that needs to change and it needs very badly to
                       So apart from my strong feeling on that,
           I don't think I can give you a lot of guidance on how
           you are going to cope with your problem of getting all
           this information exchanged in this short period of
                       DR. POWERS:  And Dr. Ford.
                       DR. FORD:  I have four specific questions
           that you can pass on to the staff.
                       DR. POWERS:  Oh.  
                       DR. FORD:  You are giving them a
           challenge, and I am giving them four specific
           questions to help them meet the challenge.
                       DR. POWERS:  Very good.  Do you want to
           share them with us?
                       DR. FORD:  Well, we have already gone
           through it in the other meeting.  It is the CDF
           situation and FIC, and FAC, and the corrosion/ erosion
           cracking.  I can give them to you.  I have gotten them
           written out.
                       DR. POWERS:  Okay.  
                       MR. SHUAIBI:  Dr. Powers, can I ask a
                       DR. POWERS:  Certainly.
                       MR. SHUAIBI:  This is Mohammed Shuaibi of
           the staff again.  Is it your perception that the
           entire safety evaluation is this way, or is it just
           inadequate in certain areas?
                       DR. POWERS:  I did not in the course of
           the presentation find an area that we asked questions
           in that I thought was handled in a way that was
           reassuring.  Well, I take that back.  I found the
           answers to the NPSH margin questions by the section
           head were answered promptly and explicitly.
                       MS. KAVANAUGH:  Thank you.
                       DR. POWERS:  Now, the criterion question
           that Dr. Wallis asked still is more nebulous, but I
           don't know that you are responsible for that in this
           application.  Okay.  Any other comments that the
           members would like to make?  
                       Have we given you -- I'm sure that we
           haven't given you enough, but would you like to hear
           me talk anymore?
                       MS. MOZAFARI:  No, I think we have an
           idea.  We will go back and revisit our conclusions,
           and our evaluations to make sure that we have been
           clear enough about the basis for the evaluations.
                       DR. POWERS:  Feel free to interact with
           Mr. Boehnert, who will be in a position to pass on any
           clarifications that you might need.
                       MS. MOZAFARI:  Okay.
                       DR. POWERS:  With that, I will turn the
           meeting back to Professor Wallis.
                       CHAIRMAN WALLIS:  I would like to thank
           the representatives from Duane Arnold and GE, and the
           staff, and my colleagues for their contributions to
           this meeting, and I will adjourn the meeting.
                       (Whereupon, the opening meeting was
           recessed at 12:20 p.m.)


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