483rd Meeting - June 6, 2001

                Official Transcript of Proceedings


Title:                    Advisory Committee on Reactor Safeguards

Docket Number:  (not applicable)

Location:                 Rockville, Maryland

Date:                     Wednesday, June 6, 2001

Work Order No.: NRC-251                               Pages 1-259

                   NEAL R. GROSS AND CO., INC.
                 Court Reporters and Transcribers
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                                 + + + + +
                            483RD ACRS MEETING
                                 + + + + +
                               JUNE 6, 2001
                                 + + + + +
                            ROCKVILLE, MARYLAND
                       The Advisory Meeting met at the Nuclear
           Regulatory Commission, Two White Flint North, Room
           2B3, 11545 Rockville Pike, at 8:30 a.m., Dr. George E.
           Apostolakis, Chairman, presiding.
                       DR. GEORGE E. APOSTOLAKIS, Chairman
                       DR. MARIO V. BONACA, Vice Chairman
                       DR. DANA A. POWERS, Member
                       DR. WILLIAM J. SHACK, Member
                       DR. ROBERT  E. UHRIG, Member
                       DR. GRAHAM M. LEITCH, Member
                       DR. THOMAS S. KRESS, Member at Large
                       DR. JOHN D. SIEBER, Member
                       DR. F. PETER FORD, Member
                       DR. GRAHAM  B. WALLIS, Member
           ACRS STAFF:
                       DR. JOHN T. LARKINS, Executive Director
                       DR. ROBERT ELLIOTT,  ACRS Staff
                       CAROL A. HARRIS, ACRS/ACNW
                       HOWARD J. LARSON, ACRS/ACNW
                       DR. JAMES E. LYONS, ADTS
                       SAM DURAISWAMY, ACRS
                       DR. SHER BAHADUR, ACRS
                       DR. AUGUST W. CRONENBERG
                       DR. J.N. SORENSEN
                       MARK CUNNINGHAM
                       ALAN KURITZKY
                       ADRIAN HAYMER
                       TONY PIETRANGELO
                       BOB OSTERRIEDER
                       JOHN A. NAKOSKI
                       GARY M. HOLAHAN
                       JACK R. STROSNIDER
                       .                                 I-N-D-E-X
                         AGENDA ITEM                       PAGE
           I.    Opening Remarks by ACRS Chairman             4
           II.   Proposed Risk-Informed Revisions to         10
                 10 CFR 50.46 and Proposed Revisions to
                 the Framework for Risk-Informing the
                 Technical Requirements of 10 CFR Part 50
           III.  Potential Margin Reductions Associated      101
                 with power Uprates
           IV.   Draft Final Safety Evaluation Report for   144
                 the South Texas Project Nuclear Operating
                 Company (SPNOC) Request to Exclude
                 Certain Components from the Scope of
                 Special Treatment Requirements Required by
           IV.   Discussion of General Design Criteria      220
           .                           P-R-O-C-E-E-D-I-N-G-S
                                                    (8:30 a.m.)
                       CHAIRMAN APOSTOLAKIS:  The meeting will
           now come to order.  This is the first day of the 
           483rd meeting of the Advisory Committee on Reactor
                       During today's meeting the Committee will
           consider the following:  A status report on proposed
           risk-informed revisions to 10 CFR 50.46, and proposed
           revisions to the framework for risk-informing the
           technical requirements of 10 CFR Part 50.
                       The potential margin reductions associated
           with power uprates; the draft final safety evaluation
           report for the South Texas Project Nuclear Operating
           Company request to exclude certain components from the
           scope of special treatment requirements required by
           regulations; and the discussion of general design
           criteria and proposed ACRS reports.
                       This meeting is being conducted in
           accordance with the provisions of the Federal Advisory
           Committee Act.  Dr. John T. Larkins is the designated
           Federal official for the initial portion of this
                       We have received no written comments or
           requests for time to make oral statements from members
           of the public regarding today's sessions.  A
           transcript of portions of the meeting is being kept,
           and it is requested that the speakers use one of the
           microphones, and identify themselves, and speak with
           sufficient clarity and volume so that they can be
           readily heard.
                       I will begin with some items of current
           interest.  The ACRS Subcommittee on Advanced Reactors
           held a meeting on June 4th and 5th, 2001.  We would
           like to thank Commissioner Diaz for his outstanding
           keynote speech.
                       Also, we would like to thank all the
           meeting participants, especially the presenters and
           the panel members.  This meeting was successful
           because of the outstanding support provided by the
           ACRS management, and Richard Savio, Michael Markley,
           and Medford L. Ztoftorie (phonetic).
                       Our special thanks to the administrative
           support provided by the Operations Support Branch
           personnel, especially Jenny Gallo, and Carol Harris,
           Beverly Joe White, Tyrone Brown, Michelle Kelton, F.
           M. Bernard, Tania Winfried, and Sherry Meadow.
                       I understand that we have a change in our
           management of the ACRS staff, and Dr. Larkins will
           tell us about that.
                       DR. LARKINS:  Good morning.  It is a bit
           of good news and a little bit of not so good news. 
           When you bring employees on board for a lot of
           expectations and potential, your hopes are that they
           are going to develop and move on, and do some other
                       Unfortunately, other people recognize the
           expertise and potential of the staff here, and Mr.
           Lyons, who has been with us since I guess -- what is
           it, September, Jim?
                       MR. LYONS:  Yes.
                       DR. LARKINS:  He has been selected to be
           the new Director of the Future Licensing Organization,
           which is going to be a tremendous job and
           responsibility in the agency.
                       We just spent two days talking about
           future licensing for advanced reactor designs.  So,
           Jim is going to have a major challenge, and although
           I hate to lose him, we still wish him good luck.
                       MR. LYONS:  Thank you.  First of all, I
           would like to thank the committee for all the --
           actually education that I have gotten since I have
           been here on this staff.
                       And I would like to thank John and Dana
           for selecting me to come to this position, and it has
           really been very useful for me to see exactly how the
           committee works, and to see all the breathe of
           experience that you all have, and the issues that you
                       And I really want to thank you for holding
           the workshop the last two days to bring me up to speed
           on my new job.  It was very nice of you to do that.
                       CHAIRMAN APOSTOLAKIS:  It was a parting
                       DR. LARKINS:  With that, I am pleased to
           announce that Dr. Sher Bahadur has been appointed the
           Associate Director for Technical Support.  Sher will
           be replacing Jim effective July 9th.
                       For those of you who are not familiar with
           Dr. Bahadur, he joined the NRC in 1984, and has held
           a number of progressively more responsible positions. 
                       It is interesting to note that I was the
           technical assistant for Chairman Zech in the early
           '80s, and when I left to take a position in NOR, Sher
           was my replacement as the technical assistant to the
                       So he knows his way around the Commission
           and will be very helpful.  He has worked both in the
           Office of MNSS and he has also worked in research, and
           I think his current position there is chief,
           engineering research applications branch.  So he will
           bring a balanced perspective and I should be able to
           dump lots of work on him.
                       Prior to joining the NRC, Dr. Bahadur
           worked in a variety of assignments in the private
           sector, including NUS, Acres American, Incorporated,
           and Lundy Engineering.
                       Dr. Bahadur has a Ph.D. in geotechnical
           engineering from the South Dakota School of Mines
           Technology, but even more importantly, I think he
           brings a wealth of experience and background in a
           number of areas that will impact both committees, the
           ACRS and the ACNW.
                       So I am looking forward to having Sher
           around for a little longer, at least a year or two,
           and working with the committee.  So welcome aboard. 
           thank you.
                       DR. BAHADUR:  Thank you, John.  As you
           mentioned, I have been in research for about 12 years
           now, and I have looked after three different branches
           during this 12  years.  So I think there is a wide
           breathe of experience that I have received in that
                       And I am looking forward to working here
           now and learning with the committee, and also bringing
           the expertise in certain areas, which we will be
           useful to you, as will for my own development.  So
           thank you so much again, and I am looking forward to
                       CHAIRMAN APOSTOLAKIS:  Thank you.  We have
           three letters to complete at this meeting, and the
           response, and they are all top priority.  There is the
           response to Chairman Meserve's May 7th memorandum on
           the differing professional opinion on steam generator
           tube issues.
                       And the response to the April 12th EDO
           letter on topics raised by the ACRS pertaining to
           issues associated with industry use of thermal-
           hydraulic codes, and risk-based performance
                       We will also discuss our letter on the
           South Texas project exemption request, but the letter
           will be completed in July, and so we have three
           letters.  And the first session is on proposed risk
           informed revisions to 10 CFR 50.46.
                       As you see from the agenda, we had
           allocated almost two hours or three hours or more --
           well, more than two hours to this subject.  But we
           will only take until 10 o'clock, and after the break,
           we will come back and discuss Dr. Wallace's letter on
           thermal hydraulic codes.
                       So with that, we will start on the
           proposed risk-informed revisions to 10 CDR 50.46.  Dr.
           Shack will lead us through this.
                       DR. SHACK:  We will be discussing the
           status of the staff industry initiatives in 10 CFR 50-
           46, and the industry proposal is fairly straight
                       They propose that -- and loss of cooling
           accidents, and some other range defined upon a plant
           by plant or a plant class basis through analysis and
                       The staff has a wider range of options
           that they are considering for 50.46 and presumably we
           will hear something about that range of options that
           they are considering this morning, and Mark will start
           us off.
                       MR. CUNNINGHAM:  Thank you, Dr. Shack. 
           Good morning.  My name is Mark Cunningham, and I am
           the Chief of the PRA Branch in the Office of Research. 
           With me this morning is Alan Kuritzky, a senior
           reliability and risk analyst in the branch.
                       As Dr. Shack indicated, we are going to
           try and give you some information on the options that
           we are considering on making modifications to 50.46 to
           make it more risk informed.
                       Right off the bat, I am going to take the
           slides slightly out of order, and to go to slide three
           and talk about the purpose of the meeting.  Basically,
           we had hoped to have a commission paper to you a
           couple of weeks ago for you to review.
                       We weren't able to do that for a variety
           of reasons, and so we want to give you a status report
           today on our work to consider changes to 50.46, and
           use this as an opportunity to solicit feedback, and
           get questions from the committee on our proposals.
                       We are not requesting a letter at this
           point.  We intend to get the commission paper -- the
           commission paper is due to the EDO in about three
           weeks.  We intend to get it to you in time so that you
           could discuss it at the July meeting, and at that
           point we would ask for a letter.
                       Going back to slide two then, and an
           outline of the presentation, basically first we want
           to provide some background just to remind people where
           we are in the series of steps that are undertaken in
           option three.
                       I want to spend a little time talking
           about what is in 50.46, and the different aspects of
           50.46.  We want to give you some options for different
           ways, and discuss some possible different ways to
           change the requirements, and discuss a little bit
           about what future technical work might be required to
           support these possible changes.
                       And to summarize a couple of policy
           issues, and then end up with some discussion of
           schedule.  Just as a reminder to the committee and
           others, if we go back a couple of years to a
           commission paper that laid out the plan for performing
           option three, and it was described in Section 99.264.
                       It laid out a framework, and the framework
           basically had two phases in it.  The first phase was
           a kind of identification and evaluation phase that we
           went through or had gone through everything in Part
           50, and tried to identify what aspects or what
           requirements within Part 50 might be amenable to being
           changed to be risk informed.
                       We prioritized those and identified 2 or
           3 issues as the most likely or the most important
           changes to tackle first.  The first of those was 50.44
           on combustible gas control.
                       As the committee knows, we provided
           recommendations to the commission last September on
           that, and there is a rule making plan now before the
           commission to make those rule changes.
                       The second priority that we identified
           were potential changes to the ECCS requirements
           contained in 50.46 and other places in the
           requirements.  And Part C of the first phase is --
                       DR. POWERS:  Mark, remind me why you
           thought that was  50.46 was particularly susceptible
           to risk information?
                       MR. CUNNINGHAM:  A couple of reasons
           really.  One was that there was a fair amount of risk
           information  already available that would help guide
           you in possible changes to the ECCS requirements.
                       There is a lot known about the frequency
           of breaks and the frequency of core damage associated
           with different types of breaks, and that sort of
                       It was also recognized that there is a
           fair amount or there are opportunities in 50.46 where
           you could make some -- improve the realism of the
                       DR. POWERS:  Well, I think everybody
           recognized that there were things that were bound in
           the nature with 50.46, and I guess I am interested in
           why you thought that particular regulation was just
           right for risk information.
                       I think you are on the right track when
           you say that a lot of information -- that we knew a
           lot about breaks.  I mean, we have looked at
           everything from micro breaks to macro breaks, and we
           know something about the reliability that the ECCS has
           to have to counterman those breaks.  It would seem
           like pretty good reasons to go after that one.
                       MR. CUNNINGHAM:  Another big factor I
           think was that 50.46 is one of the centerpieces of
           Part 50 if you will, in the sense that the --
                       DR. POWERS:  It is a little linchpin with
                       MR. CUNNINGHAM:  It is a linchpin that you
           start to change, and we saw an opportunity that if you
           start with 50.46, you could have the opportunity not
           only to change the ECCS requirements, but have an
           opportunity downstream to make other changes to the
           requirements, because there are many if you will
           spinoffs from 50.46 and other parts of the
                       And somebody has described it as an
           octopus of having tentacles that reach out into many
           other parts of Part 50.  So there is an opportunity to
           start working that whole set of issues.
                       And perhaps to put it another way, if you
           don't tackle 50.46, you may have a hard time changing
           other parts of Part 50 as well.  So it was the
           combination of things.
                       We thought that we could have some
           successes that would be relatively low-cost and quick
           to do.  We had a good set of information to work from
           on with the risks associated with different pipe
           breaks, and again we saw that it was such a
           centerpiece of Part 50, and we thought it was
                       DR. SHACK:  And I think you could also
           argue that there is a substantial safety benefit.
                       MR. CUNNINGHAM:  Yes.
                       DR. POWERS:  I mean, I think that most
           people would argue that what we are doing to the
           diesels is not helpful.
                       MR. CUNNINGHAM:  Yes, and certainly that
           point has been made a number of times, and related
           issues on diesel generators -- start times and that
           sort of thing -- that have been argued to be counter
           to safety in some respects.
                       And also to be clear, when we polled the
           nuclear industry, and NEI provided us their ideas of
           what they thought would be most important to change,
           the ones that they identified right off the bat was --
           the top two were 50.44 and 46.
                       DR. POWERS:  You have a lot of information
           on breaks from the studies that have been going on for
           over -- gee, since '74, and we have been looking at
           various kinds of breaks since then.
                       Do you really have a lot of information on
           this hypothesized counter to safety or what we can do
           to poor, innocent diesel generators?
                       MR. CUNNINGHAM:  Do we have the same type
           of level of information?  No, we don't, I don't think,
           but I think it is the more mechanical engineering
           types and things like that will say that the
           requirement to start these diesels as they are
           required to do with having cold starts, and that have
           to be extremely fast, it is counter to good sense if
           you will in the design of these diesels.
                       They are very big machines, and it is not
           a good way to pursue it.
                       DR. POWERS:  Yes, but the only thing that
           one would worry about is why not just go fix that?
                       MR. CUNNINGHAM:  Because again there are
           other opportunities, and looking at the complete issue
           that I will come back to in a little while on ECCS
           reliability, is that there are -- that the
           requirements that we have that are implemented today
           cause us to perhaps over design some aspects of the
           ECCS that can lead to potential safety issues in other
                       I have been before this committee several
           times to talk about pressurized thermal shock risk. 
           One of the issues that comes up is that if you are
           putting greater demands to pump in cold water to deal
           with large LOCAs, then you may be improving the risk
           associated with large LOCAs.
                       But you may be hurting our potential to
           deal with pressurized thermal shock, or increasing the
           risk associated with pressurized thermal shock.
                       DR. POWERS:  To raise an event in order to
           avoid an AB?
                       MR. CUNNINGHAM:  Yes, that's right.
                       DR. POWERS:  And so it is probably not a
           good tradeoff.
                       MR. CUNNINGHAM:  Yes.  And given that we
           think there are conservatisms in the current 50.46, I
           think we can do a better balancing job if you will
           between those two sets of requirements.
                       DR. LEITCH:  Has it been decided at this
           point which is the next regulation beyond 50.46 to be
                       MR. CUNNINGHAM:  We have been spending
           some time looking at special treatment requirements,
           but by and large now I think for the near future our
           focus is going to be on getting 50.44 done and 50.46,
           our hands-on 50.46 if you will.
                       So as I said, with 50.44 in a sense, we
           are down in this context of the framework option three
           and we are down in the phase two part for 50.44.  We
           are into rule making and that sort of thing.
                       And in the context of 50.46, we are back
           here, in terms of the latter part of the last phase or
           the last part of phase one, and we are looking at the
           feasibility of possible changes.
                       So in that sense what you will hear about
           today is us talking about what is the technical
           content of 50.46, and what would lead us to some
           alternatives, and what is the basis for some
           alternatives to the present 50.46.
                       Are there policy issues that have to be
           resolved, and what would be the required technical
           work to proceed, and in some sense the resources that
           would be required to proceed with different
                       So the bulk of my presentation is really
           going to cover that sort of thing.  The paper that we
           owe to the commission in June is a set of
           recommendations to proceed if we be believe that it is
           appropriate, to proceed to rule making.
                       And then if the commission approves, then
           we would go on into the phase two work.  But in a
           sense this is setting you up to make it clear that
           there are a lot of things that we don't have answers
           for today.
                       We think there are some good opportunities
           for change here, but we don't have all the detailed
           technical work done to provide the real basis for
           this, or the complete basis for this.
                       Moving on now to what is in 50.46.  And
           50.46, in a sense, has four parts.  The first part
           deals with the concept of assuring system safety
           function, and to assure that the requirements talk
           about basically ensuring that the system can operate
           given single failures.
                       That the system can operate given the
           assumption that there is a loss of off-site power.  In
           effect, this first box here is a first attempt at
           defining a reliability requirement for the ECCS.
                       So we are going to come back to this later
           that there may be a better way to ensure reliability,
           rather than working with single failure and
           assumptional off-site power.
                       So a key theme of what you will hear today
           is changes to the reliability aspect of the ECCS
           requirements.  The second part is dealing with what is
           an acceptable ECCS performance, in the context of
           ensuring that we don't have a core melt accident, or
           a severely damaged core.
                       Right now there are five criteria within
           50.46 and other places that are used to measure that. 
           The classic one or the most well known is 2,200
           degrees F, in terms of peak clad temperature.
                       But there are others in terms of the
           maximum allowed cladding oxidation, and hydrogen
           generation, and a number of other things.  Again, we
           see in this case some opportunities for making -- and
           some reasons to make this a little more general
           perhaps, and improve the quality of the requirement in
                       DR. POWERS:  The requirements for maximum
           clad oxidation of no more than 17 percent is not
           really related to hydrogen generation is it?  It is
           really an embrittlement criteria?
                       MR. CUNNINGHAM:  It is an embrittlement
           criteria, exactly.
                       DR. POWERS:  And as we are discovering
           lots of things in embrittlement of the clad besides
           oxidation and what not are you a part of the same
           increased realism to change that to be an honest-to-
           god embrittlement requirement, rather than a --
                       MR. CUNNINGHAM:  We will come back to
           that, but yes, that is a direction we are moving in. 
           The third aspect of 50.46 and related requirements
           deals with the acceptable model that is used to
           compare with the performance criteria or the
           acceptance criteria.
                       Currently, there is an Appendix K approach
           to modeling ECCS, the thermal hydraulics of it, and
           then there is also another alternative for a realistic
           with uncertainty analysis approach.
                       And we see some opportunities there worth
           making some changes that could make or improve the
           requirements.  And finally the last part is the
           definition of the range of break sizes that are
           required to be mitigated by the ECCS system.
                       Basically now the requirement is that it
           has to include up to and including the largest pipe
           break in the system.  Again, we will talk some more
           about some possible changes to that as we move on
                       DR. POWERS:  I was intrigued by the
           requirement that a volume be able to withstand the
           rupture of the largest pipe in that volume.  I am
           familiar with a reactor not located in the United
           States, and which had that requirement for it, and it
           is containment modules.
                       And it succeeded in blowing its
           containment modules up completely because it broke
           several of the largest pipes.  But do you bear those
           things in mind in thinking about these pipe breaks?
                       MR. KURITZKY:  You mean in breaking
           multiple -- in having multiple breaks at the same
                       DR. POWERS:  Well, I mean, the requirement
           is not to blow up the containment volume or things
           like that.  I mean, it is coming in and taking it back
           and saying, well, it is no bigger than this break that
           takes you one step removed from what you really want
           to accomplish, which is not to break the volume.
                       MR. KURITZKY:  Right.  I mean, we have
           certainly taken into consideration the containment
           integrity.  I mean, changes that we will recommend
           involving ECCS, we will always be keeping in mind that
           we don't want to violate the containment, and we take
           containment in strong consideration if that is your
                       DR. POWERS:  The containment that I was
           speaking of was the internal containment, and with an
           environment exactly like this, and that could
           withstand the break of the largest pipe in the volume. 
           Unfortunately, it broke 12 of them, and that was more
           than it could take.
                       MR. CUNNINGHAM:  This slide is intended to
           kind of provide the basic, if you will, kind of some
           boundary conditions to what we will talk about for the
           rest of the morning here.
                       As I mentioned earlier, I think a theme
           that you will see is that I think there is something
           to be gained and we have considered seriously ways to
           improve the description of the reliability
           requirements for the ECCS system.
                       And getting away from this rather
           prescriptive statement of single failure criteria and
           loss of off-site power, and there is ways to do things
           better and perhaps improve the reliability of the ECCS
                       Another one of our boundary conditions is
           that we see some opportunities and parallel and as
           part of being risk informed to improve the realism of
           what we have here in the ECCS requirements.
                       You will see in each case, I think, a
           couple of different approaches to accomplishing our
           goal, and in some cases we have changes that might be
           still fairly prescriptive, but still improved over
           what we have today.
                       But there is still a kind of more
           prescriptive oriented changes, and we also have
           approaches that are more performance based.  So I
           think in each case you will see alternatives that
           might be somewhat less prescriptive than today, but
           still prescriptive.
                       And then others that are more bigger steps
           if you will and to be more performance based types of
                       DR. WALLIS:  And while we are talking
           about ECCS reliability, you are not suggesting that
           the ECCS be designed so that it cannot cope with a
           double ended break?
                       You are just saying that the way in which
           it copes with it doesn't have to be as reliable as we
           thought it had to be?  Is that what you are saying?
                       MR. CUNNINGHAM:  What I was saying is that
           in the present requirements the way of ensuring
           reliability of the system for the spectrum of breaks
           is a somewhat artificial way of -- well, it is done
           somewhat artificially, and the assumed single failure
           in the system, and the assumed loss of off-site power.
                       And you can accomplish the same
           reliability perhaps in a more risk informed way
           without necessarily -- perhaps even improving the
           reliability to cope with the system.
                       But we are not saying that the ECCS does
           not have to cope with the largest break in the system.
                       DR. WALLIS:  Are you doing something like
           a product of the probability of the break, and the
           reliability or probability of the success of the ECCS
           or something?
                       MR. CUNNINGHAM:  Yes, exactly.
                       DR. WALLIS:  And if the probability of the
           break is very low, then the probability of the ECCS
           working can be less than 99.99 percent or whatever?
                       MR. CUNNINGHAM:  Yes, exactly.
                       DR. WALLIS:  That is the argument?
                       MR. CUNNINGHAM:  Yes.
                       DR. WALLIS:  And we are certainly not
           backing off on the capability of the thing to respond
           to a large break?
                       MR. CUNNINGHAM:  No, it is not.
                       DR. WALLIS:  I think that should be clear
           to the public that you are not backing off on that
           sort of requirement?
                       MR. CUNNINGHAM:  That's right.
                       CHAIRMAN APOSTOLAKIS:  So is the same
           thinking then applicable to the reactor for which the
           core damage frequency is very, very low, so we can
           relax the reliability requirements of the containment?
                       MR. CUNNINGHAM:  Relax the reliability
           requirements on what?
                       CHAIRMAN APOSTOLAKIS:  On the containment? 
           In other words, we are shifting.  If you think in
           terms of the cornerstones, we are saying that the
           initiating event or the core damage frequency is so
           low that now the barriers that follow may not be
                       MR. KURITZKY:  I think we based everything
           on our framework document, which maintains or which
           states that we have to maintain the defense in depth
           layers, which containment of course is one.
                       So in our framework, we should not be
           doing anything that allows to get through a layer.
                       CHAIRMAN APOSTOLAKIS:  In this case.
                       MR. CUNNINGHAM:  Yes, in this case.
                       CHAIRMAN APOSTOLAKIS:  But that is the
           next logical step isn't it?
                       MR. CUNNINGHAM:  Yes, that's right.  If
           you could take the same framework that we are working
           on here, and we are applying the framework to existing
           plants.  So they have a containment, and they have a
           ECCS, and that sort of thing.
                       And the next step in a direction of
           advanced reactors is to think about this framework if
           you have nothing but a paper reactor if you will.  And
           is today's balance the right balance for a new plant. 
           That's a good question.
                       DR. WALLIS:  Well, I liked your argument
           earlier that if you change some of these requirements
           that you might actually make the system safer, because
           you are not putting greater demands on the system in
           some other scenario.
                       If you can make that argument, I think you
           have a good one.  If it is just backing off alone,
           that is not such a good argument.
                       MR. CUNNINGHAM:  It is not just backing
           off it.
                       DR. WALLIS:  It is actually improving
           safety if you can make that argument, and I think that
           is a good one.
                       MR. CUNNINGHAM:  Yes.  Again, one of the
           last ground rules for the flavor of what we are doing
           here is the issue that has been raised on the
           definition of whether or not you can eliminate the
           large break LOCAs as a design basis accident.
                       I think you will hear some more later that
           there are some possibilities that that could be done,
           but there is also a lot of technical work that would
           have to be done to justify that.
                       And how far we go in this particular paper
           in opening the door for that is subject to some
           discussion, and we will come back to that later.
                       DR. POWERS:  But that would be the case
           then where the ECCS would no longer be capable of
           handling the largest break?
                       MR. CUNNINGHAM:  Conceivably, yes.  That
           if you could make a convincing argument that there is
           a set of pipe breaks, or pipe breaks of a greater than
           certain size are extremely low frequency, then in a
           sense you shift, and the pipe breaks over into the
           category that we would do for a vessel rupture.
           That it is an event of such a low frequency that you
           do not require ECCS mitigation.
                       DR. WALLIS:  However, if it did happen, it
           would be embarrassing if you had already decided to do
           away with the ability to cope with it, low frequency
           or not.
                       MR. CUNNINGHAM:  It would be embarrassing,
           and a dangerous situation.  And I believe as was
           discussed about a month or so ago with a subcommittee,
           I guess, there is a lot of technical work that the
           staff believes would have to be done before you could
           make that case.
                       And even if you did a lot of technical
           work it is not clear that you could get to that end
                       DR. KRESS:  Mark, do you have a list of
           potential changes that the licensee will make if you
           change the definition of the pipe size for a large
           break LOCA.
                       MR. KURITZKY:  Industry has supplied us
           with a couple of fairly extensive lists of things that
           they would like to change if they could, and change
           the definition of a large break.
                       DR. KRESS:  Okay.
                       MR. CUNNINGHAM:  And we didn't come
           prepared to talk about that today.  But I think it is
           clear that if you could accomplish that that there
           would be a lot that would change in the operations of
           the plant, and in the design and in probably the
           operations of the plant.
                       DR. POWERS:  If all those things were
           implemented, and I realize that it is kind of a
           hypothetical list that maybe not all plants could
           eliminate, and could do all things.
                       But have you taken a representative plant
           and done a risk analysis on it to see if there is a
           change very much?
                       MR. CUNNINGHAM:  We have not done that at
           this point.  Again, we are in the -- and again to go
           back to the slide on where we are in the procession of
           tasks, we are at the point of do we think it is
           feasible to make some changes.
                       And then if we were going to make those
           changes, then we would proceed to do more work like
           that, but we are not at the point of having to do
                       DR. POWERS:  Well, it seems to me that if
           you found that the risk went up significantly that you
           wouldn't want to bother trying to find out if it was
           feasible to make the changes.
                       MR. CUNNINGHAM:  Certainly, and that comes
           into the feasibility part of it.  And what you will
           see in the presentation is that we are not coming in
           and saying that our approach is to eliminate the large
           break LOCA design basis accident.
                       We think that today there is a lot of
           technical work that would have to be done to justify
           that.  We may want to start down that path, and I
           think that our goal was to start down that path to
           talk about how that might be done.
                       But the changes that we are talking about
           in the shorter term are less radical changes to the
           requirements, but things where I think we can improve
           a much better balance to what is in the ECCS
                       DR. POWERS:  And based on evidence from
           yesterday, the Chairman here, who is looking for
           radical --
                       DR. WALLIS:  Well, Mark, not only do you
           have to do what you think is right, you have to
           respond to what industry is asking for.
                       MR. CUNNINGHAM:  Yes.
                       DR. WALLIS:  And if they come in with very
           good arguments that do away with a large break LOCA,
           you have to be on good technical grounds to respond.
                       MR. CUNNINGHAM:  Yes.
                       DR. WALLIS:  And you may have to do some
           of this technical work or maybe all of it.
                       MR. CUNNINGHAM:  Well, when we come back
           later on and we talk about the future --
                       DR. SHACK:  On page 57 of your notebook,
           there is a fairly detailed description of the things
           that they would like.
                       DR. KRESS:  Thank you, Bill.
                       DR. POWERS:  And that they think they can
           get out of this.
                       DR. KRESS:  Thank you, Bill.  Handwritten
           on page 57?
                       DR. SHACK:  Yes.
                       MR. CUNNINGHAM:  Dr. Wallis, yes, the
           industry or representatives of the industry have
           proposed certain approaches, and we and the staff have
           -- and again at the subcommittee meeting, we talked
           about some of the issues that would have to be
                       And I think that since then we have talked
           with the industry, and are prepared to continue the
           dialogue on how those issues could be resolved.
                       DR. WALLIS:  And if you remember, they
           said they would go away and prepare a really good
           case.  So you have to be ready for that.
                       MR. CUNNINGHAM:  Yes, and I know that the
           members of the staff are trying to set up a series of
           meetings to talk about that.  I don't think they have
           been scheduled yet, but I think the idea is to go
           forward and talk about that.
                       DR. WALLIS:  I am just saying that talking
           is fine, but someone has to do a really good technical
           analysis which is convincing.
                       MR. CUNNINGHAM:  Yes, we agree.
                       DR. KRESS:  Mark, I have a bit of a
           strange question, I guess.  We have a number of design
           basis accidents that the plants are required to meet,
           and this is one of them.  And we are talking about
           changing or may possibly change the design basis
                       The question I have is that isn't there a
           rationale that has been used by the agency to select
           design basis accidents, their description and what
           they are, and some sort of rationale that says we will
           choose this as a design basis accident because it has
           these attributes?
                       And it is sort of top down approach to the
           question of the design basis accident; and then the
           next question would be that if you had that rationale,
           what pipe size goes into meeting those criteria or
           whatever they are?
                       I suspect that we don't have such a
           rationale, but I guess part of the question is should
           such a rationale be developed in an explicit manner,
           rather than -- I suspect that it has grown from
           intuition and other things.
                       MR. CUNNINGHAM:  The set that is in
           existence today for the operating plants is this one
           as you know that has evolved over time, and one of the
           challenges in thinking about changing those is to go
           back in 50.46 or something else and look at the intent
           of the requirements when they were established.
                       And in some cases that is very hard to do
           because the decisions were made 25 or 30 years ago, or
           more, and it is hard to discern from the record what
           all the intents were at the time.
                       DR. KRESS:  Part of my motivation for
           asking the question doesn't really have to do with
           this one, but has to do with advanced reactors.
                       MR. CUNNINGHAM:  That's right.
                       DR. KRESS:  If the tendency or the choice
           is to go with we will dream up some more design basis
           accidents --
                       DR. POWERS:  Well, I think you want to be
           careful with that.  I don't believe that you will find
           that the design base accident set is capricious or
           dreamt up.
                       DR. KRESS:  No, I didn't mean to impugn it
           like that.
                       DR. POWERS:  It is developed in a fairly
           disciplined fashion to test safety systems without a
           great deal of duplication, but with some bounding
           nature to it.
                       There are a whole bunch of accidents that
           one can dream up that are not labeled design basis
           accident accidents because they are covered by other
           existing design basis accidents.  It has been a very
           disciplined process I think.
                       DR. KRESS:  Well, it is the discipline and
           rationale that I wanted to see explicit, so that I can
           then apply that discipline to the advanced reactors
           and say, all right, for this reactor type and style,
           these are good choices for design basis accidents
           because they have these attributes that you mentioned.
                       Plus, there may be others, and I would
           like to have those attributes somehow based in risk
           considerations, too, rather than --
                       DR. POWERS:  Well, I actually think there
           is an NRC document that maybe two minutes ago I could
           have quoted the title to you, but I can't right now,
           that actually outlines some of the philosophy on how
           design basis accidents are --
                       DR. KRESS:  Selected.
                       DR. POWERS:  -- defined and selected,
           because we have gone through this exercise before.  I
           mean, this is not the first -- well, when the FFTF and
           Clinch River were in the offing, we had to go through
           these exercises once before.  So people have actually
           looked at these kinds of things.
                       DR. KRESS:  Yes, but I suspect it was
           before we focused so heavily on reasons.
                       CHAIRMAN APOSTOLAKIS:  Well, if I wanted
           to have a design basis accident that would draw on
           risk information as Dr. Kress just said, wouldn't I
           need to know which accident sequences are affected by
           this regulation?  Did you collect those?
                       MR. CUNNINGHAM:  You would want that
           information, yes.
                       CHAIRMAN APOSTOLAKIS:  Do you have it?
                       MR. CUNNINGHAM:  I think we do, yes.  But
           again I don't have it here today, but I think we have
           a sense --
                       CHAIRMAN APOSTOLAKIS:  Right.  I think it
           would be nice for us to see that, and at least it
           would be interesting to me to see it.
                       DR. KRESS:  Yes, George, and it is those
           sequences that I want to see that not only affect CDF
           and our alert, but I would like to see the sequences
           that have to do with possibly other regulatory
           objectives.  Frequency of releases of fusion products
           of higher frequency, lower magnitude, in CDF alert
                       CHAIRMAN APOSTOLAKIS:  Well, that's
           perfectly fine, but what I am curious about is that if
           I have a bunch of sequences and ventries, then maybe
           we can say, look, this particular design basis
           accidents addresses this piece here, and that piece
           there, and that piece there.
                       And see whether we cover the whole
           spectrum of sequences and how, because the accident is
           not just the way -- the way I understand it, the
           design basis accident is not just a large break LOCA. 
                       It is a stylizing, and plus single
           failure, and so that would be an interesting thing to
           see.  And maybe something is left out.  That would be
           a basis for defining the DBAs.  By the way, it is not
           just the logic behind the position.
                       I think one of the great advantages of
           having DBAs is really that they facilitate the
           interaction with the licensee.
                       DR. KRESS:  Yes, really great.
                       CHAIRMAN APOSTOLAKIS:  I mean, it is one
           thing to say go do a PRA, and then we talk, and quite
           another to say these are the things that we expect you
           to do, right?
                       DR. KRESS:  If you had a risk in some
           informed way to select design basis accidents, I think
           we have a problem, and it is because your purpose of
           making design basis accidents is to ensure that the
           design ends up with a risk status that needs
           acceptance criteria.
                       CHAIRMAN APOSTOLAKIS:  Yes.
                       DR. KRESS:  And we don't have acceptance
           criteria that includes uncertainties, and defense in
           depth, and releases the lower fusion products, and
           worker exposure.  We don't have risk related
           acceptance criteria.  So I think we have a problem.
                       CHAIRMAN APOSTOLAKIS:  Well, I think
           looking at the sequences --
                       DR. KRESS:  Well, that would be well
           worthwhile.  That would give you a lot of insight.
                       CHAIRMAN APOSTOLAKIS:  Is that out of the
           question to do this month?
                       DR. KRESS:  Could we have that tomorrow?
                       MR. CUNNINGHAM:  Well, I will tell you
           what we will be giving you in this part of the paper
           at the end of the month, and maybe this at least
           addresses part of what you are talking about.
                       DR. WALLIS:  Well, I like what George is
           saying because once you have got that, then you could
           say, well, suppose we make this change in these DBAs,
           how will that perturb the sequences.
                       CHAIRMAN APOSTOLAKIS:  Exactly.  And are
           there any sequences of any consequence.
                       VICE CHAIRMAN BONACA:  I really wonder,
           however, if there is that document that will have all
           this information.  I think that this thing has evolved
           through 40 years.  I mean, we have plants that were
           designed originally without ECCS systems.
                       So somebody evidently did not think that
           you could have a break of a pipe of the size of that
           size.  And then somehow we began to think that there
           was a realistic possibility.
                       And at some point when all this
           information was developed and put together into a
           document, where a true companion to all the
           information and guide was developed, and I am not sure
           that it was.
                       DR. POWERS:  This is an element of
           history.  The people that did the thinking that, gee,
           there could be a break in this system and it won't
           work, was the ACRS.
                       VICE CHAIRMAN BONACA:  I don't know where
           it came from, but what I am saying is that I am not
           sure it only came only from the NRC.  I mean, the
           industry was very active.  I mean, the NRC standards
           had the specific particularization of events and
           postulation of those.
                       And there was a lot of interaction, and I
           was just wondering if there was -- because there was
           a document where all of these have been brought
                       MR. CUNNINGHAM:  I don't know of such a
                       CHAIRMAN APOSTOLAKIS:  I don't think there
           is such a document.
                       DR. WALLIS:  Well, there was a long set of
           public hearings.  I mean, there was the ECCS hearings
           that went on for a long time, and as I remember it,
           the view of some parts of industry and the AEC was
           that this will never happen, and we don't have to
           design for it.  And there was all this public
           hullabaloo when out of that came the ECCS criteria.
                       MR. CUNNINGHAM:  Yes.  I was speaking
           slightly more generally.  I am not aware of something
           where you could look at all of the design basis
           accidents and have that type of information available.
                       Again, part of our discussion in the
           attachment to the June paper is here are from risk
           analyses the important sequences that are associated
           with ECCS.
                       And we have something like that that maps,
           you know, in a sense of trying to get to the issue of
           what does PRA tell you about the importance of ECCS as
           a function and that sort of thing.
                       So that piece of it will be there, and
           that is just scratching the surface of what you are
           trying to get at.
                       DR. POWERS:  And an importance measure for
                       VICE CHAIRMAN BONACA:  Actually, that kind
           of reflection took place very much in the early PRAs,
           because that was factored in with the set of accidents
           from Chapter 15, and then there was a lot of
           discussion of are they covering the whole spectrum,
           and what else should be there.
                       And there were different issues,
           especially initiation of events from electrical faults
           that were added that were not considered in Chapter
                       So maybe then there was a lot of -- I
           don't know.  Maybe in some of the early PRAs there was
           a discussion of that.
                       MR. CUNNINGHAM:  But you are right.  The
           PRAs started with a set of -- on the books were
           already a set of design basis accidents, and then we
           moved beyond that.
                       But something like station blackout is --
           I don't believe is a design basis accident, but we
           have requirements to mitigate that.
                       CHAIRMAN APOSTOLAKIS:  That came later in
           the PRAs, right?
                       MR. CUNNINGHAM:  I'm sorry?
                       CHAIRMAN APOSTOLAKIS:  It is not the
           design basis, but the rule came because of the PRAs,
                       MR. CUNNINGHAM:  Yes, but there is not a
           Chapter 15 accident that is --
                       CHAIRMAN APOSTOLAKIS:  How about the small
           breaks?  They are not a design basis?
                       MR. CUNNINGHAM:  Yes, they are.
                       DR. FORD:  Could I ask a question more for
           my clarification?  When you are looking at the
           overview, and the thing that you showed before, when
           you come down to the last box, the ECCS cooling
           performance for number and sizes, and locations of the
           breaks, that isn't a very plant specific, because
           presumably it would be due to environmental
           degradation, and the size, and the geometry of the
           initiating defects in the pipe.
                       Is this something that is going to be
           addressed later on this program?  Am I way ahead of
           the problem here?
                       MR. CUNNINGHAM:  Okay.  In this context,
           basically it is -- well, the requirement is imposed in
           a sense without the detailed analysis of what might be
           the degradation mechanisms and that sort of thing.  It
           is that you have to have an ECCS that deals with the
           biggest pipe break.
                       DR. FORD:  So the question you are asking
           is if I had this sort of geometry and disposition of
           cracks, then this is what I would do.  But when it
           comes down to the practicality of a utility, or a
           plant, coming to you, then could they not say, well,
           we are never going to have -- the probability of my
           having such a system of defects is very, very low.
                       And that would go into your probablistic
           risk assessment, and you would come out with a very,
           very low number.  Is that a possibility for the
           future, or is that ---
                       MR. CUNNINGHAM:  Yes.
                       DR. WALLIS:  And is that the way that you
           are going --
                       MR. CUNNINGHAM:  That's certainly from the
           Westinghouse owners group and things like that, they
           in a sense made an argument along those lines, or
           started an argument along those lines.
                       And they said for our piping and this type
           of thing, we are not -- we don't see a credible way to
           get the large double-ended pipe break.  They don't
           think it is credible.
                       DR. KRESS:  Except for the large double-
           ended pipe break, that argument would tend to be plant
           specific.  If you are going to hone in on a specific
           size, it makes the regulation very difficult it seems
           to me.
                       MR. CUNNINGHAM:  And we get into this, and
           it might be vendor specific.
                       DR. KRESS:  It might be vendor specific.
                       MR. CUNNINGHAM:  Or something like that.
                       DR. FORD:  Or operational specific.
                       MR. CUNNINGHAM:  Yes, that's right, and
           that is a lot of the -- if we were to try and back
           away from the, if you will, somewhat artificial
           distinction that it will be the largest pipe break,
           and try to back off from that, you have to get into
           these issues.
                       DR. FORD:  So right now -- and I am just
           trying to calibrate myself as to what we are
           discussing here, you are talking about really a worst
           case scenario?
                       MR. CUNNINGHAM:  Yes, and the question
           that we are trying to get to, or one of the questions
           that we are trying to deal with is how can we -- is it
           credible to back away from that worst case pipe break
           history if you will, and do we have a technical basis
           to back away from it.
                       DR. FORD:  But that technical basis has
           been something that we will discuss not today.
                       MR. CUNNINGHAM:  Not today.
                       DR. WALLIS:  And if you go back to the
           history, you will find that the reason for this was
           really not technical.  It was all this hullabaloo in
           public, and that this is what seemed to the public to
           be the maximum credible scenario.
                       There is a lot of reason for that which is
           not technical probably, and if you go back to the
                       MR. CUNNINGHAM:  I wanted to take the next
           four slides or so and go back and talk a little more
           about each of the four boxes that were on this slide
           that we just showed.
                       In terms of the, if you will, the
           reliability aspect of the ECCS or functionality --
                       CHAIRMAN APOSTOLAKIS:  Did you do number
                       MR. CUNNINGHAM:  This is number seven. 
           I'm sorry.
                       CHAIRMAN APOSTOLAKIS:  Oh, okay.  Sorry. 
           So the answer was no, you didn't do it?
                       MR. CUNNINGHAM:  No, not yet.  Turning to
           slide seven, in terms of the elements of the ECCS
           requirements that deal with reliability of the system,
           again we are considering a risk-informed alternative
           to 50.46, and would basically turn it into, if you
           will, a true reliability requirement.
                       DR. KRESS:  Now, Mark, are you viewing
           this as the LOCA frequency times the ECCS liability
           equates to core damage frequency?
                       MR. CUNNINGHAM:  Yes, basically.  The
           underlying concept for the more performance based part
           of this is that the frequency of the challenge and the
           reliability of the ECCS has to be balanced if you
           will, so that you have reached some acceptable value.
                       So that the lower of the frequency of the
           initiator, the lower the requirements on the
           reliability of the ECCS.
                       DR. KRESS:  Now, this balance, is it going
           to be conditioned to 10 to the minus 4 per year level?
                       MR. CUNNINGHAM:  I'm sorry, 10 to the
           minus 4?
                       MR. KURITZKY:  We have not decided on that
                       DR. KRESS:  You have not decided on what
           that level is?
                       MR. CUNNINGHAM:  No.  We think or we have
           it in mind, and that will be the subject of other
           discussions with the committee and things like that
           later on as we get into more of the details of this. 
                       It is really -- yes, there is a value that
           we have in mind, 10 to the minus 4, or whatever.
                       MR. KURITZKY:  One point is that we feel
           that it should be derived from the framework.  The
           framework has quantitative guidelines and we feel that
           whatever value we come up with should somehow be tied
           to that framework.
                       DR. WALLIS:  Well, this is a sort of a
           one-by-one.  You say that the large break is very
           infrequent, and therefore the reliability or response
           does not have to be so big.
                       But then the more sophisticated way is to
           look at all spectrums of all breaks, and choose the
           ECCS system so that there is some sort of integral of
           a reliability frequency over all breaks is the best.
                       MR. CUNNINGHAM:  Yes.
                       DR. WALLIS:  And it may well be that
           putting all the emphasis on the big break is very bad
           for the optimization of the entire response.
                       MR. CUNNINGHAM:  Yes.
                       DR. WALLIS:  And that would be a really
           good idea.
                       MR. CUNNINGHAM:  Well, ideally, we would
           have a well-defined frequency of a pipe break size,
           versus frequency.
                       DR. WALLIS:  And then we would match the
           rotation as well.
                       CHAIRMAN APOSTOLAKIS:  Can you really do
           it so neatly?
                       MR. CUNNINGHAM:  No.
                       CHAIRMAN APOSTOLAKIS:  I mean, as you look
           at the accident sequence, it seems to me that there
           isn't such a thing as ECCS.
                       MR. CUNNINGHAM:  That's part of it.  In
           effect, there is an ECCS function that covers many
                       CHAIRMAN APOSTOLAKIS:  Exactly.
                       MR. CUNNINGHAM:  There is low pressure
           injection, and high pressure injection, and things
           like that.  So you end up splitting this continuous
           distribution if you will into probably ranges, and
           that's probably more where we will end up.
                       And that is for the range of pipe sizes
           between this and this, then you would have to have
           commensurate reliability of this.  And then break that
           into however many pieces.
                       DR. KRESS:  The reason that I threw out
           this number of 10 to the minus 4 is because I was
           hoping that you weren't going to use that, because
           this is one little set of sequences among all of them,
           and there is some other value that is more appropriate
           than that.
                       MR. CUNNINGHAM:  Yes, and it would not be
           10 to the minus 4 for just the reasons that you are
           talking about.
                       CHAIRMAN APOSTOLAKIS:  Even though we
           don't like to allocate, right?  It may be a good idea
           though to let Mark finish what he has to say on each
           view graph.
                       MR. CUNNINGHAM:  That could be.
                       CHAIRMAN APOSTOLAKIS:  And then jump into
                       MR. CUNNINGHAM:  You may be right.
                       CHAIRMAN APOSTOLAKIS:  Except for the
           Chairman, of course.  Shall we let him say what he has
           to say?  Go ahead.
                       DR. SHACK:  We can try.
                       CHAIRMAN APOSTOLAKIS:  We can try, yes.
                       MR. CUNNINGHAM:  So, again, we are looking
           now at two possible ways of getting at this
           reliability issue.  One is what I was just saying, is
           that it is a fairly performance based oriented type of
           thing, and it was to match the reliability to the
           frequency of the challenge.
                       And then you get into traditional if you
           will reliability analyses if you will of the systems. 
                       CHAIRMAN APOSTOLAKIS:  So the word
           performance there means what?
                       MR. CUNNINGHAM:  Performance in the sense
           that -- well, non-prescriptive in one sense.
                       CHAIRMAN APOSTOLAKIS:  But it is not in
           the sense that we are using it in performance based
           regulation, right?
                       MR. CUNNINGHAM:  But it could be.  One
           other aspect of this possibly is that we recognize
           that frequency of challenges -- our state of knowledge
           if you will about the frequency of pipe breaks --
           changes with time.
                       So that the performance or the
           requirements on the reliability may change with time
           also.  So one aspect of a performance based type of
           thing might be that you say they have to meet some
           value, the product has to meet some value; and as one
           changes with time, then the other may be able to
           change with time also.
                       CHAIRMAN APOSTOLAKIS:  My personal opinion
           is that you need a better word.  Performance based is
           something else.  I mean, you collect evidence, and --
                       DR. WALLIS:  I like it in contrast to the
           second alternative.
                       CHAIRMAN APOSTOLAKIS:  Right.  But some
           other word would be better, such as reliability based,
           or reliability -- well, something like that.
                       MR. CUNNINGHAM:  Well, it is different
           than what we had talked about in other contexts.
                       CHAIRMAN APOSTOLAKIS:  Right, and we don't
           want to start using words.  We have already a problem
           with nomenclature.
                       MR. CUNNINGHAM:  Well, perhaps non-
           prescriptive approach or something.
                       CHAIRMAN APOSTOLAKIS:  Non-prescriptive 
           or risk oriented, not based.
                       MR. CUNNINGHAM:  All right.  The second
           alternative that we are considering is more
           prescriptive.  It is to recognize that in one aspect
           of this somewhat artificial way that we look at
           reliability today, is that we recognize that for the
           very large pipe breaks that there is the probability
           of having this simultaneous loss of off-site power
           that is a requirement, and could be a very low
                       And so the other option that we are
           considering is in a sense for a set of pipe breaks
           where we think we can argue that the simultaneous loss
           of off-site power isn't credible, and you remove that
           requirement for that set of pipe breaks.
                       But the rest of it still tends to look
           like what is in the requirements today, with that
           exception.  It is more prescriptive, and it is a small
           step towards ensuring towards a risk-informed
           approach.  But we are considering it as an option.
                       CHAIRMAN APOSTOLAKIS:  What is functional
           reliability?  Is it the probability that it will do
           its job?
                       MR. CUNNINGHAM:  It's function, yes.
                       CHAIRMAN APOSTOLAKIS:  Now, in the South
           Texas exemption request, the word functionality is
           used in that sense?
                       MR. CUNNINGHAM:  I think so, yes.
                       CHAIRMAN APOSTOLAKIS:  And so the
           probability that it will do its job?  I am not sure it
           is the same meaning.
                       DR. WALLIS:  I am not sure either.
                       CHAIRMAN APOSTOLAKIS:  It is not the same
           meaning.  I think it is asking to make sure that the
           thing will work, and is not asking about the
           probability that it will do the job for a period of
                       MR. CUNNINGHAM:  Yes, but the term
           functionality -- and like in South Texas or something,
           that is a little bit different.  Functionality is
           different than functional, and again perhaps
           functionality here is not the right word.
                       CHAIRMAN APOSTOLAKIS:  Oh.  I think in the
           South Texas context --
                       DR. SIEBER:  If it will work.
                       CHAIRMAN APOSTOLAKIS:  -- all we want to
           know if it will work, and if it can do the job.
           Actually, that is really what they mean.  That it can
           do the job.  Now, how reliability it will do it is a
           different story.
                       DR. WALLIS:  It could do the job if it
           were reliable.
                       CHAIRMAN APOSTOLAKIS:  I'm sorry?
                       DR. WALLIS:  It could do the job if it
           were reliable.  It is contingent upon it being
                       CHAIRMAN APOSTOLAKIS:  But it can be
           unreliable and still capable of doing it.
                       MR. CUNNINGHAM:  Yes, even if it is
           unreliable, it could have functionality.
                       CHAIRMAN APOSTOLAKIS:  Yes, and so I think
           that when it comes to the treatment requirements, and
           that is what they are worried about.
                       MR. CUNNINGHAM:  Okay.  We are not there
           yet, and we are using the word -- again, this is
           probably functional reliability.  That is a good
           point.  We don't want to confuse this with the context
           of functionality.  Yes, you are right.
                       So this is where we are today in terms of
           the reliability aspect of it, and I think I heard the
           committee, or a couple of the members anyway weren't
           overly enthusiastic about this, and the more
           prescriptive oriented.
                       DR. WALLIS:  Well, you wanted some input
           don't you and comments?
                       MR. CUNNINGHAM:  Yes.
                       CHAIRMAN APOSTOLAKIS:  So is anybody
           offering any comments?
                       DR. KRESS:  About what?
                       CHAIRMAN APOSTOLAKIS:  What you prefer.
                       DR. KRESS:  Well, I have a comment, but
           not necessarily about that slide.
                       CHAIRMAN APOSTOLAKIS:  Oh, okay.
                       DR. KRESS:  But what it appears to me is
           that we are at the heart of it, and what we are
           beginning to embark on is allocating acceptable risk
           among a subset of sequences without real
           considerations of what the uncertainties are, and what
           this does to the uncertainties.
                       And how or what the rigor of the
           quantification of defense in depth is associated with. 
           I have some real concerns about the process, and as
           you know, I have talked about this before.
                       CHAIRMAN APOSTOLAKIS:  When I mentioned
           the sequences, I included the uncertainties.
                       DR. KRESS:  Oh, okay.
                       CHAIRMAN APOSTOLAKIS:  You might say that
           this requirement is here because the uncertainty of
           the sequence is too large.
                       DR. KRESS:  But we don't have a good
           measure of what too large is, and a subset of
           sequences, and so there is a lot of -- I mean, I am
           not against this process, and I think it embarks on a
           method that we can learn a lot from.  But I think
           there is --
                       CHAIRMAN APOSTOLAKIS:  I will give you an
           example.  In some of the sequences, I am sure that the
           redundancy of the system is defeated by human error. 
           But yet that is not a single failure, part of the
           single failure criteria is it?
                       MR. CUNNINGHAM:  No, it's not.
                       CHAIRMAN APOSTOLAKIS:  Single failure
           criteria refers to hardware?
                       MR. CUNNINGHAM:  Yes.
                       CHAIRMAN APOSTOLAKIS:  And so there you
           have it.
                       MR. CUNNINGHAM:  Certain aspects of
           hardware, too.
                       CHAIRMAN APOSTOLAKIS:  Certain aspects of
           hardware, exactly.
                       MR. CUNNINGHAM:  That's right.  Again, it
           was an approximation to a reliability requirement, and
           I think we could do a better job today.
                       CHAIRMAN APOSTOLAKIS:  And that was
           established 40 years ago or whatever.
                       MR. CUNNINGHAM:  Yes.
                       CHAIRMAN APOSTOLAKIS:  And the state of
           knowledge was different than.
                       MR. CUNNINGHAM:  Yes.
                       CHAIRMAN APOSTOLAKIS:  So retaining the
           single failure criteria doesn't sound like such a good
           idea, unless you expound the definition.
                       MR. CUNNINGHAM:  And that is a
           possibility, too; is an intermediate step that is more
           -- a little more current.
                       CHAIRMAN APOSTOLAKIS:  I mean, I don't
           know how much time you have because I know that 3 or
           4 weeks is not a long time.  If you could include some
           of these thoughts regarding the sequences in your
           report, that would be really very helpful.
                       And, you know, to speculate a little bit
           on this when it was placed because at that time they
           didn't have the benefit of sequences, but it is always
                       MR. CUNNINGHAM:  The background document
           that we will be providing was one of the attachments,
           and it talks about some of the history of how the
           requirements were established.
                       And it is looking at why are they as they
           are, and then another piece is what does risk analysis
           tell you about what the effect of those requirements
           on the reliability.
                       CHAIRMAN APOSTOLAKIS:  Are you going to
           have any of those oldtimers reviewed that document,
           people who were present when the ECCS hearings were
           taking place?
                       DR. KRESS:  Joe Murphy.
                       CHAIRMAN APOSTOLAKIS:  Joe Murphy for
                       DR. POWERS:  But he was so young at that
           time that he --
                       CHAIRMAN APOSTOLAKIS:  Yes, we are talking
           about who were active in it, but are now retired.
                       DR. WALLIS:  Well, Denny Ross was here
           wasn't he?
                       MR. CUNNINGHAM:  We have Dr. Wildben back
           there who is very much involved in helping us look at
           this issue, and he has been around a couple of years,
           and has been through a number of these things.  I
           believe that he was involved in the ECCS requirements. 
                       DR. POWERS:  Please use the microphones.
                       CHAIRMAN APOSTOLAKIS:  Okay.  No comment.
                       MR. CUNNINGHAM:  It is noted that Dr.
           Wildben, who was involved in this, was around at all
           of those times if you will.
                       CHAIRMAN APOSTOLAKIS:  Okay.  Good.
                       MR. KURITZKY:  Mark, if I could make just
           one point, is to make it clear that when we are
           listing -- for instance, in this case, we have two
           options under there.  It is not that we are viewing it
           necessarily as we are going either with one or the
                       But that they would both go forward
           possibly, and then the licensee could choose to do
           either one.
                       MR. CUNNINGHAM:  Or at this point again we
           are at the point of feasibility, and we are going to
           look in the further technical work that we are doing
           after we have gone to the Commission, and we would be
           investigating both of these options as to whether or
           not they really make sense in terms of alternatives in
           the rule.
                       CHAIRMAN APOSTOLAKIS:  All right.
                       MR. CUNNINGHAM:  Since I am running out of
           time here fairly quickly, in the context of the
           acceptance criterium, basically the goal if you will
           is to revise the acceptance criteria such that the
           ECCS performance during the course of the accident is
           shown to maintain coolable core geometry.
                       So it is more of a fundamental thing of
           getting to the issue of what is the point of 17
           percent, and it really is not dealing with hydrogen,
           and it is not dealing with that.  It is a maintaining
           a coolable core geometry.
                       CHAIRMAN APOSTOLAKIS:  So this is a
           functionality issue isn't it?
                       MR. CUNNINGHAM:  Yes.
                       DR. WALLIS:  We have to be careful there. 
           Almost any geometry is coolable eventually.  I mean,
           that is not a very good definition.  Coolable without
           the release of something, or put some constraint on
           it.  Eventually it is going to be cool, one way or
                       MR. CUNNINGHAM:  Yes, you're right.
                       DR. POWERS:  This fascinates me.  What do
           you mean?
                       DR. WALLIS:  Well, I mean to say that you
           may well have a core geometry which is a terrible
           mess, and which is still coolable.  But it is not
           coolable in a way that you would really like to see
                       DR. POWERS:  I am still very confused.  If
           I put a bunch of core down on the bottom of the lower
           plenum --
                       DR. WALLIS:  It is coolable.
                       DR. POWERS:  And it is coolable -- and I
           don't imagine that it is coolable, but for a
           hypothesis that it is coolable --
                       DR. WALLIS:  Well, if it gets hot enough,
           it will be cooled.
                       DR. POWERS:  No, it won't.  It will
           penetrate the vessel.
                       DR. WALLIS:  That's how it gets cool.
                       CHAIRMAN APOSTOLAKIS:  We are going to run
           out of time at 10 o'clock, and we have to stop this at
           10 o'clock.
                       MR. CUNNINGHAM:  So again in this case,
           when we look at this issue of --
                       DR. WALLIS:  Maybe we don't need to stop
           at 10 o'clock.
                       MR. CUNNINGHAM:  In this issue of the
           acceptance criteria, we are considering a more
           performance oriented one, which is that you show us by
           test that the cladding integrity is maintained, and so
           that gets to this issue of is a rubble bed an
           acceptable end point.
                       So we are being a little more specific
           there that it is not.  Again, you could be more 
           prescriptive, more like the current requirements, and
           say I want to have or I am going to require through
           evaluation a certain temperature and cladding
           oxidation be maintained.
                       DR. KRESS:  Mark, if they wanted to show
           that the cladding integrity  was maintained, they will
           have to show that it is below a peak cladding
           temperature and that the oxidation is below a certain
                       MR. KURITZKY:  Well, actually, the first
           point we are talking about is actually like a
           recompression test.  It actually would do an actual
           physical experimental test to show that the cladding
           maintained some feasibility.  It would be an
           analytical type of test.
                       DR. SHACK:  Just before the LOCA.
                       DR. KRESS:  Yes.  I don't think that
           anybody is going to offer to do that are they?
                       MR. CUNNINGHAM:  Again, today I think --
           well, we will be back to you to talk to you about all
           of these points as we proceed into the second phase of
           the work.
                       So, again, this will give you a flavor of
           where we are going, but it is not trying to give you
           the answer of whether or not either of these makes --
           well, the rationale behind either of these. We will be
           back with you, I'm sure, in the near future.
                       DR. LEITCH:  The long term cooling bullet
           would be retained?
                       MR. KURITZKY:  The long term cooling
           bullet?  It would be subsumed in the fact that now in
           the wording that revised ECCS acceptance criteria,
           such as the ECCS performance for the duration of the
           accident, or some such words.
                       DR. LEITCH:  So it alludes to some time
                       MR. KURITZKY:  Yes.
                       MR. CUNNINGHAM:  We are also considering
           possible changes to the evaluation model, the thermal
           hydraulic model as well.  We are looking at again a
           series of options in things that we are considering.
                       One is to replace the current requirement
           on the decayed heat with the 1994 ANS standard.  It is
           a more recent standard, with some description of the
           uncertainty that would go with that.
                       And that's in lieu of something where it
           is an older decayed heat curve with a 20 percent
           margin on top of it.  So we think 20 percent may be
           excessive, and we could put something in more
                       Again, the option is in -- and in the
           requirements, if they are acceptable today, is to use
           a realistic model with uncertainty propagation, and
           they can do that today, and in typical practice,
           people don't, because of the complexity of it.
                       Another option that we are considering is
           that for certain low frequency pipe breaks, we might
           be able to relax the modeling requirements to get away
           from the requirement for uncertainties, and say you
           can do a best estimate for very low frequency
                       In terms of the possible large break LOCA
           redefinition, again the requirement on the books today
           is that it has to be the largest pipe break in the
                       One thing that we are considering is
           changing the wording in the rule today so that you
           could -- to open the door a little bit to say that it
           is either that or some alternative that is deemed
           acceptable by the commission.
                       In rule making that would introduce the
           possibility of getting at the -- at perhaps the
           Westinghouse issue of can we show you that the large
           break LOCA, or that certain classes of breaks are not
                       This in rule space would allow you to
           pursue that, and without having to go to another rule
           change, permit that type of an analysis.
                       DR. POWERS:  When Westinghouse says that
           something is none, let me assure you something is not
           credible.  I mean, I am a very credible guy, credulous
           guy.  I mean, I can imagine lots of things.  What is
           the proof that something is not credible?
                       MR. CUNNINGHAM:  This comes in a sense to
           the next slide, which is in --
                       DR. WALLIS:  I don't think anything is
           incredible.  You have to define it in terms of
                       MR. CUNNINGHAM:  Well, what I just showed
           you before would allow from a rule standpoint some
           flexibility in what the staff could approve and what
           licensees could use.
                       This is a summary of what was provided at
           the subcommittee meeting a month or two ago on what
           would have to be the technical justification, or some
           of the technical issues that would have to be
           addressed in order to demonstrate credibility or
           incredibility if you will.
                       DR. POWERS:  Again, Mark, could this be
           done without the reg guide that defines this, and
           leave that open, or you would really envision that
           this change couldn't be made until you were ready to
           issue a reg guide?
                       MR. CUNNINGHAM:  Since we have today, that
           change could be made to the requirement as part of the
           rule making without a reg guide.  I think that is the
           sense that we have.
                       The reg guide could at least conceptually,
           if we deal with these issues, then you could deal with
           that, and you don't have to go back and change the
                       There are a lot of practical problems that
           would have to be dealt with in the course of that, but
           we don't think that we would necessarily have to have
           the reg guide when we made that wording change in the
                       DR. POWERS:  I am still struggling with
           what makes something incredible.  You have up on your
           slide in service experience.  Well, we have not had a
           whole lot of large pipe breaks, and so that certainly
           is not a fertile field to mine there.
                       I mean, we have got a few cracks in them,
           and maybe that is a more fertile field than I think. 
           And analyses, I am very confident that within obscure
           computer codes and things like that, that you can
           generate frequencies that are small.
                       But does it mean that I have to show that
           never in the history of pipes in this world be a pipe
           of this sized break?
                       MR. CUNNINGHAM:  No, I don't think so.  We
           consider vessel rupture in regulatory space as an
           incredible event, in the sense that it is not of
           sufficiently low frequency that we do not have to
           require ECCS to mitigate that type of failure.
                       That is not to suggest that there has
           never been vessels of that type that have failed or
           not failed in world history if you will.  But it is a
           combination of -- that in a sense, and perhaps
           implicitly, it becomes a sense that the probability of
           such a failure is low or very low, and that the
           confidence or the uncertainty in that probability is
           small enough that you can have confidence that it is
           not going to happen.
                       DR. POWERS:  I am going to keep asking
           because I am still struggling with this.  Okay.  When
           these guys do these calculations, they usually
           hypothesize about lipsoidal cracks and certain aspect
           ratio, and what not.
                       Of course, there are no cracks that look
           at all like that are hypothesized in the computer
           codes.  So there is a lot of uncertainty here and what
                       What kind of percentile of a conceivable
           distribution do they have to get to, to say okay, it
           is incredible here?
                       MR. CUNNINGHAM:  I don't know that I have
           a good answer for that, because I think that at some
           point it becomes that quantitative information leads
           to a qualitative judgment that it is close enough.
                       DR. POWERS:  Well, presumably it has to be
           on the order of what you accept for a pressure vessel?
                       MR. CUNNINGHAM:  Oh, yes, from that sense,
           we accept certain things, and --
                       CHAIRMAN APOSTOLAKIS:  What is that, 10 to
           the minus 6?
                       DR. POWERS:  Well, we are still debating
           that, but on that order.
                       MR. CUNNINGHAM:  Yes, on that order, and
           in the PTS space, you say if the risk associated with
           a PTS induced vessel rupture is 5 times to the minus
           6 or less, it is acceptable.
                       DR. KRESS:  But that doesn't seem like a
           good choice to me, and I will tell you why.  The
           consequences of a pressure vessel rupture are surely
           much greater than the consequences of this pipe
                       DR. POWERS:  That's right, but they will
           never say that.  I mean, I know this PMF guys.  They
           come along and they will say okay, the nominal
           probability for a single crack is 3 times 10 to the
           minus 45th, or something like that.  I mean, they come
           up with very low numbers for this sort of thing.
                       And they will say, yeah, but there is the
           possibility that cracks will interlink and things like
           that, and I don't know how to deal with that.  So it
           could be a higher probability, and they will pick a
           number like 10 to the minus 5th, and it could be up
           that high.
                       And what Mark is saying is that there has
           to be some confidence limit with that, and I am trying
           to find out what the confidence limit has to be.  Does
           it have to be 99 percent confident that the
           probability is 10 to the minus 6th or lower?  Or does
           it have to be 95 percent, or 80 percent, or --
                       DR. KRESS:  Yes, I have wrestled with that
           question on other issues.
                       DR. POWERS:  I know you have.
                       DR. KRESS:  And there is no clear
           technical way to arrive at the confidence level unless
           one goes to the utility function, which is not exactly
           technically arrivable at.
                       DR. POWERS:  Well, right now I am on a
           very specific thing.  What if Westinghouse said that
           it takes to show something this is incredible?  I am
           very credulous.  I mean, I can believe lots of things. 
           I even believe in 10 to the minus 45th for cracking in
           BWR welds.
                       DR. LEITCH:  Aren't we really saying then
           that anything above this alternate size, if there was
           some alternate size approved, that anything above that
           is going to lead to core damage?
                       MR. CUNNINGHAM:  It could be that or it
           could be that anything above that size does not have
           an ECCS system that has to meet the requirements of
           50.46, although there may still be some mitigative
           capability in the plant, but not safety related if you
           will.  There are several alternatives for that.
                       DR. KRESS:  Anything above that alternate
           size contributes a contribution to the CDF at a
           probability or confidence level that is unacceptable,
           or that is acceptable.
                       So you have a confidence level that the
           contribution to CDF of any pipe above that is
           acceptable, and none of those things have been
           rigorously defined to my knowledge what the confidence
           level is, or what is an unacceptable contribution to
           CDF for a subset of sequences.
                       But that is their problem, and they have
           to wrestle with something like that.  I think that is
           the basic concept.
                       MR. CUNNINGHAM:  Again, there will be
           other opportunities, and we will be back before the
           subcommittee or the full committee to talk about all
           of these issues that we are wrestling with here as
           time progresses and as the rule making proceeds.
                       DR. LEITCH:  Before although there you say
           that the ECCS systems exist and no one is going to
           tear out ECCS systems, yet some of the testing
           criteria -- I mean, what will go along if this is
           approved, and then people will start to ask for a
           relaxation on testing criteria out of service time,
           and diesel, and all those kinds of things.
                       MR. CUNNINGHAM:  Yes.
                       DR. LEITCH:  And they would no longer be
           able to demonstrate to the same degree that we can
                       MR. CUNNINGHAM:  And clearly we see that
           as one outcome, is that there could be relaxation in
           the text specs and that sort of thing as an outcome,
           and again using risk information that would suggest
           that that could be justified without having a
           substantial increase in risk or anything like that, at
           least for the large breaks and things like that.
                       And to some degree there is an element
           from risk analysis that would tell you that there is
           some degree of over design of the ECCS for the very
           largest breaks.  Mr. Chairman, it is 10 minutes till. 
           Did you --
                       CHAIRMAN APOSTOLAKIS:  Keep going.
                       MR. CUNNINGHAM:  Okay.  Just to give you
           an idea of what things we think will be coming back to
           the committee to talk about over or during this second
           phase of our work, assuming that the Commission tells
           us to proceed, we have hit on a number of these.
                       Such as developing the method and dealing
           with, for example, on how you deal with uncertainties
           on ensuring the reliability requirements match the
           frequency of the challenge.
                       And the LOCA frequency versus size
           information; and the resolution to what degree we can
           either eliminate or modify the current large break
           LOCA basis accident given the industry's interest in
                       Again, the technical basis for some of the
           changes to the evaluation methods, and what would a
           new decay heat curve look like and that sort of thing. 
                       And then this issue that we talked about
           earlier of the technical basis, and saying what is an
           acceptable post-quench ductility, and what does that
           really mean.  I think we would anticipate coming back
           to the committee on all of those issues.
                       DR. FORD:  I have a question on the first
           bullet in engineering.  There is going to be a time
           dependence to that statement?
                       MR. CUNNINGHAM:  Yes.
                       DR. FORD:  What is your timing on all of
           this, and who is going to do all this work?  You have
           got two problems with that particular bullet.  One is
           the information necessary, the factual information on
           the time dependence of the development of the flaws. 
                       MR. CUNNINGHAM:  Yes.
                       DR. FORD:  This is a very large
           engineering topic.  Another one is how you apply time
           dependence to PRA, which I understand is not done
           here; is that correct?  There are two major problems
           there; time and effort.  Is there a limit to that, or
           should we even be discussing this?
                       MR. CUNNINGHAM:  Well, again, in the
           concept of how you build time dependence and aging
           effects and things into PRAs, we have done some first
           steps, some good first steps along the way in that
                       In terms of the frequency versus size
           information, I think we need to be able to -- in this
           context is it sufficient to be able to deal with the
           reliability requirements on the current ECCS systems.
                       So I think in this case be able to have a
           fairly crude approximation of this, and still get
           something that is satisfactory for being able to set
           the reliability requirements.
                       So I think at least in my mind that it is
           achievable, because we can be fairly crude in what we
           are doing.  The people that we have talked developing
           a fairly good curve of this if you will, and that is
           years worth of work.
                       And I think we can do less than that and
           get an acceptable answer for what we are trying to
           accomplish on the reliability requirements.  On the
           second part of it, the resolution of whether or not
           the large break LOCA definition could be -- the DBA
           could be eliminated, there is a lot of work.
                       And again at this point, we are going to
           be interacting with the industry to see if we can get
           some agreement on what the extent of that work would
                       DR. POWERS:  Mark, why is it that you want
           to remake the reliability requirements commensurate
           with the challenge frequencies, and not the product of
           challenge frequencies and the consequences of failure
           to meet that challenge?
                       MR. CUNNINGHAM:  The interest in -- to me,
           I would say that those would be the same thing.  That
           you would end up with a product that is fairly -- of
           the two that is fairly consistent across the spectrum
           of break sizes.
                       DR. POWERS:  So what you are saying is
           that the consequences are all the same?
                       MR. CUNNINGHAM:  In this case, we are kind
           of defining it so that the reliability of ensuring
           that a certain consequence isn't achieved, or that the
           reliability for ensuring that adequate coolable
           geometry or that type of thing.
                       CHAIRMAN APOSTOLAKIS:  You could look at
           the spectrum of planned damage space that the PRAs
           define and see which ones would be effective by these.
                       MR. CUNNINGHAM:  Yes.
                       CHAIRMAN APOSTOLAKIS:  And work with the
           frequency of those, rather than the total --
                       MR. CUNNINGHAM:  Yes, and we talked --
           when we talked about this today, we talked about it in
           terms of CDM, but containment performance is still --
           we are going to deal with both.
                       The policy issues that we expect to see in
           the paper, one is that we are attacking, if you will
           the issue of the single failure criteria, and here in
           the context of the ECCS requirements.
                       A single failure criterion applies to
           other parts of the requirements as well.  One is that
           we are considering putting in a recommendation in the
           paper that would ask the commission's approval to
           proceed to identify where else in the requirements of
           Part 50 that we would take on this reliability concept
           if you will, or attack the single failure criterion.
                       DR. POWERS:  The ECCS really has a two
           failure requirement criterion; is that right?
                       MR. CUNNINGHAM:  I'm sorry, but I didn't
           hear the question.
                       DR. POWERS:  The ECCS really has a two
           failure requirement?
                       MR. CUNNINGHAM:  Yes.
                       DR. POWERS:  There is a power requirement
           and the failure of any other system?
                       MR. CUNNINGHAM:  Yes, that's right, and so
           we would be revisiting the combination of those
           things.  Another policy issue is in the context of
           selective implementation.
                       We have talked about this in the context
           of 50.44, and the same issue applies here, of whether
           or not if somebody wants to use this risk-informed
           alternative, whether or not they can pick and choose
           within the risk-informed alternative, like 50.44 would
                       And in 50.44, we recommended it, and the
           commission approved it, that there not be selective
           implementation within a rule.
                       CHAIRMAN APOSTOLAKIS:  Right.
                       MR. CUNNINGHAM:  And just quickly here
           again, we owe you a copy of the commission paper here
           towards the end of this month, and we would like to
           come back to you in July, and --
                       VICE CHAIRMAN BONACA:  How big is that?
                       MR. CUNNINGHAM:  The paper itself is going
           to be less than 10 pages.  There will be 4 or 5
           attachments.  One of them will be --
                       MR. KURITZKY:  It will probably be
           comparable with the 50.44 report.
                       CHAIRMAN APOSTOLAKIS:  So how can we
           review it?
                       DR. POWERS:  Read very quickly.  Actually,
           we have got lots of time, George, because July 4th is
           a holiday.  Dr. Shack, do you think we can review that
           in time to write a letter?
                       DR. SHACK:  We have to see it when it
                       CHAIRMAN APOSTOLAKIS:  And assuming it
           arrives on the 29th of June.
                       DR. WALLIS:  You can take it to Waterford
           with you and read it.
                       CHAIRMAN APOSTOLAKIS:  And if we don't do
           it in July, it has to go to September.  Do you expect
           the commission to take action from these -- I  mean,
           sometime soon, or --
                       MR. CUNNINGHAM:  It is hard to tell.  It
           is hard to tell.
                       CHAIRMAN APOSTOLAKIS:  It is going to be
           very hard for us to write a letter I think.
                       MR. CUNNINGHAM:  Well, we owe the paper to
           the EDO like on the 23rd of something like that.  So,
           maybe we can get it to you in that same time frame.
                       Obviously, we would be interested in
           getting a letter in July, and if it can't be done, it
           can't be done.  That is the committee's call
                       CHAIRMAN APOSTOLAKIS:  No, I mean, the
           point is if we write it in September and the
           Commission has already decided on whatever you ask
           them to decide, then it doesn't make sense.  Are there
           any more questions or comments from the members?
                       DR. LEITCH:  Mark, just a question as to
           the total scheme of things here, and one of the things
           that you said was that special treatment requirements
           may be a follow along situation.
                       So we are looking at later on in our
           agenda today, we are looking at South Texas with
           respect to option two, which is really an exemption
           from special treatment requirements.  But further down
           the road there may be a redefinition.
                       MR. CUNNINGHAM:  Yes.
                       DR. LEITCH:  I mean, we are putting a lot
           of if's, and's, and maybe's in there, but what is in
           our embryonic thinking here is that maybe rather than
           seeking exemption from special treatment that special
           treatment requirements could be changed.
                       MR. CUNNINGHAM:  The option two work is
           looking at the scope of special treatment
           requirements, and that is obviously what you are going
           to be hearing about today with Southern Texas and
                       The longer term effort is getting at what
           should be the environmental over qualification
           requirements for the equipment that is subject to
           special treatment requirements, and that sort of
                       But for the near future, our resources are
           going to be principally focused on 50.44 and 50.46.
                       DR. LEITCH:  I understand.
                       MR. CUNNINGHAM:  So I wouldn't expect that
           we are going to -- at least with the present
           situation, in terms of funding and things like that,
           I wouldn't expect that we would have an ability to
           deal with the special treatment requirements in the
           near future.
                       But the goal, long term, is to go back and
           revisit what should the requirements be.
                       DR. LEITCH:  Okay.  Thank you.
                       MR. CUNNINGHAM:  But it is a long term
                       DR. LEITCH:  I understand.
                       DR. SHACK:  We are running over schedule. 
           So, Adrian, and we will have the industry perspective. 
                       MR. HAYMER:  Good morning.  My name is
           Adrian Haymer, and I am with NEI, and I am a program
           manager working for the Risk Informed Regulatory
                       Tony Pietrangelo is the director, is our
           director of the Risk Informed Regulatory
           Group, and Bob Osterrieder is the project leader at
           Westinghouse, dealing with option three and redefining
           large break LOCO.
                       And what we would like to do today is just
           to give you some feedback on where we think we are on
           50.46, and risk informed regulation, or the technical
           requirements in general.
                       Because we have had some discussion with
           the staff, and we have been meeting with the staff now
           for -- certainly for 18 months or so, and discussing
           option three.
                       In January of 2000, we sent a letter
           saying where we need to focus our efforts in regard to
           option three to the Commission, and I think we have
           been consistent in our message, and we would like to
           go forward and take a look at redefining the large
           break LOCA activity.
                       And when we met I think a few months ago,
           we had some discussions with you on that, and our
           thought process has evolved a little bit, and perhaps
           we need to make some clarifications in that regard.
                       But I guess our approach on 50.46 and
           redefining the large break LOCA is what we might term
           a graded approach, and I think some of the statements
           that the staff made about their proposed language rule
           is along the lines that we were thinking.
                       In other words, you would go forward as a
           first step with taking a look at the co-incident loss
           of off-site power, and defining a break size that goes
           along with that.
                       So where they said there were two options,
           we would blend those into one, and you would then get
           a break size.  But you would still have a commitment
           or the ability to mitigate the large break.
                       But it wouldn't be the full design basis,
           Appendix B, type requirements, but you would still
           have to show the ability to mitigate the large break
           or the largest break in the plant.
                       And the language that we think in the rule
           would be very similar to what the staff mentioned a
           few minutes ago.  Tony.
                       MR. PIETRANGELO:  Yes, I think that
           summarizes it pretty well.  We think you can treat the
           double ended guillotine break more like you treat
           things in severe accident management space than as a
           design basis requirement that it currently is.
                       That double ended guillotine break
           assumption drives many of the other regulatory
           requirements in Part 50.  That is a very, very
           conservative assumption.  And we see this first rule
           making with 50.46 as really an enabling condition to
           be able to go forward, and then take a more realistic
           break size first for eliminating the coincident with
           loop and single failure that is currently in the
                       That would be the focus of the first rule
           making.  But once you have a redefined large break
           LOCA, that assumption is used in many other
           applications within the scheme of regulations, and we
           can't possibly know all the impacts in the first
           ruling making of taking a reduced large break LOCA
                       But the point is that you can't make
           changes to those other regulations based on the new
           assumption without NRC approval in each of those
           applications like we do via Reg Guide 1174 on risk
           informed applications.
                       So this first one is really an enabling
           rule.  There will be a lot of effort to look at the
           analysis and come up with a new break size will
           probably be different for each NSSS reactor design.
                       But once that is done that really sets up
           a very methodical comprehensive phased-in approach for
           taking that assumption, and promulgating it through
           the rest of the regulations, with tremendous benefits
           in terms of the focus on safety and operational
           benefits to the licensees, in terms of operating
           margin and burden reduction and cost effectiveness.
                       And so we think that this is probably the
           biggest fish in Part 50 to go after.  I think we have
           been consistent as an industry stating that since the
           letter went in in January of last year.
                       We are anxious to get on with that, and
           the Westinghouse owner's group, and Bob will speak to
           you about that in a moment, and they have already done
           an extensive amount of work looking at the analysis to
           get down to that reduced break size.  But we think
           that this is a very important effort.
                       MR. HAYMER:  And I think with had a
           question about what comes next, and I think when you
           take a look at 50.46 and some of the activities that
           we think would flow from what we have discussed, and
           what the staff has discussed in regards to defining a
           large break LOCA coincident with loss of off-site
           power and single failure, when you see what flows from
           that -- and we have given a list of those areas that
           we think would be amenable to further review once we
           have done this first step, that is a very large amount
           of work.
                       And I think once we have gone through
           that, we might then think about going back, but I
           think we are talking about a fair way down the road as
           regards those activities.
                       So that is where we see it at the moment. 
           The only other point that I would make is that we have
           given consideration that if this is beginning to take
           some time that we should think about breaking off the
           decay heat requirement into perhaps a separate rule.
                       And that is something that we will look at
           and then decide what needs to be done with regard to
           that.  Bob, did you want to say something?
                       MR. OSTERRIEDER:  Yes, just a couple of
           comments.  The question was brought up, you know, 
           what does Westinghouse or the industry feel is a good
           limit on CDF or LRF, or defining what is incredible,
           and we certainly don't want to define what is
                       But I do want to comment that first of all
           the issue of the probability of these breaks occurring
           is a key issue, and there is two areas here that we
           need to get on with in interacting with the NRC.
                       That is, the estimates of the LOCA 
           frequency, and how they are obtained in this curve of
           frequency versus break size, and about what there has
           been a bunch of discussion here.  That is the first
                       And the second piece is related, and that
           is the technical justification related to the
           frequency and what is enough rigor in the
                       We feel -- there has been a lot of
           comments here that this is a big wide open area that
           is going to take a lot of work, and what we feel is
           that we need to get some of these pinned down pretty
           quickly so that we can decide if this work is worth
                       We think that we can get together and I
           think somebody already mentioned that we are working
           on setting up a meeting with the staff to talk about
           some of these issues, and that is the next technical
           meeting that we have to schedule.
                       And we need to get that scheduled, but
           those key issues, we need to in our opinion work on
           those quickly in the near term, and decide what do we
           have to consider in these curves, and what are  the
           issues that have to be resolved.
                       And that's because right now it continues
           to be an open-ended high level, and there is more
           rigor required here, but we need to pin down what this
           rigor is on these probabilities and on the -- if we
           are going to use leak before break or something to
           justify the specific size which relates to that curve,
           we need to get those issues down on paper as to what
           they are so we can decide how to deal with them, and
           whether or not they are too extensive to deal with.
                       And I guess that is a key point, and for
           us it is a key item for moving forward.  We need to
           get into some of that in the near term and get that
           pinned down further.
                       DR. WALLIS:  I am intrigued by your
           statement that you might need more rigor on the
           probabilities.  Maybe you need more rigor on the
           effect of modal uncertainties.
                       MR. OSTERRIEDER:  Well, that --
                       DR. WALLIS:  And maybe eventually after a
           decade, somebody is going to look at some aspect of
           the codes that affect the probabilities.
                       MR. OSTERRIEDER:  Well, the rigor again,
           and when we presented our basis, and what high level
           technical basis, we were told that we would need more
           rigor in that area, and that is why I was focusing on
           that area.
                       DR. WALLIS:  Well, I am saying it is not
           just probabilities, but it is the things that affect
           the probabilities.
                       MR. OSTERRIEDER:  That's correct.
                       DR. WALLIS:  And it will always have an
           effect on success and all that kind of stuff, and it
           is all tied together.
                       MR. OSTERRIEDER:  Right.  But we are not
           focusing on changing the acceptance criteria of the
           codes, or the methods in the codes.  And again when we
           started the program, we were looking at the rigor that
           was applied in GDC-4 and the ISI programs as being
                       It has been brought up that the staff
           feels that that is not sufficient, and we need to talk
           in more detail.  There were some details brought
           forward at the March 16th subcommittee meetings, and
           we need to meet, and we hope to cover some of that in
           our next technical meeting.
                       Also, as to more specifics about why that
           is so different, and what is the basis of some of
                       MR. HAYMER:  While we are pulling on from
           that topic as we go on schedule, I think the industry
           is very interested in getting down and looking at some
           of the detailed work that the staff plans to do and
           see what we can do or have done to address those
                       And working together, we can move it
           forward, but we have got to get a better understanding
           of what we are looking at from a technical perspective
           so that we can move forward on this regulation.
                       And that brings into mind the overall
           schedule of option three, and when we started this
           activity, we said 50.44 and 50.46, and the reason that
           we selected 50.44 is that we thought it was going to
           be fairly straightforward.
                       And in truth the staff moved very quickly. 
           There were recommendations made last September and the
           Commission directed the staff to move forward with an
           expedited rule making in January.
                       And things have seemed to have gone
           silent, and now we hear that the only thing that has
           been sent up is a plan, and we don't know what that
           is, and we have been working on this now, for Option
           3, for 18 months.
                       We probably are not going to have anything
           to show the industry for at least another two years,
           and that is beginning to concern some people.
                       MR. PIETRANGELO:  Adrian is right and it
           is frustrating from our standpoint, because 50.44, the
           reason that it was selected was that it has benefited
           the licensees and there are things that we do with the
           plant with the recombiners and monitoring it that make
           no sense from a safety standpoint.
                       And really that has been a belief since
           about the late 1980s when this regulation was looked
           at under the Marginal Safety Program.  It was one of
           the three final regulations that were looked at as
           part of that program, and the only regulation that did
           get changed was Appendix J for integrated leak rate
                       And then San Onofre went through an
           exemption request on recombiners and on combustible
           gas control, and after a 2 to 3 year review by NRR,
           they finally got their exemption request in 1999.
                       We thought that was going to be the
           principal basis for the 50.44 rule making.  Yet, there
           has been a lot of other things that have been brought
           into play on 50.44 on certain containment types, and
           I won't go into great detail here.
                       But we had something that already had a
           technical basis, and was applicable to about 95
           percent of the industry.  But I think the kind of
           business as usual approach to this says that we have
           to make this rule perfect, and apply to everybody
           equally, and make sure that is all dealt with in this
           one rule making.
                       And as a result, I think you are seeing
           the schedule dragged out on this for additional
           technical basis for these other containment types, and
           new gas source terms, and all the rest.
                       While the principal benefit of this for
           the vast majority of the industry is kind of sitting
           there, you have three exemption requests sitting in
           NRR waiting to be reviewed, and others that probably
           would be submitted if they knew that this rule making
           was going to take so long.
                       So I think there has got to be a new
           mindset when we look at these improvements via Option
           3, especially when we get to something as complex as
           50.46.  When you see something that has benefit, and
           is fairly straightforward, you need to take it.
                       There may be additional work done later on
           to look at other aspects, but it should not preclude
           or at a minimum slow down to this extent the progress
           in making the regulations more risk informed.
                       That is our real message on this, because
           on 50.46, if you wait until you know everything that
           might ever happen when you go to a redefinition of
           hard break LOCA, we will never finish this.  We will
           never finish.
                       DR. WALLIS:  I am trying to disentangle
           this.  You are complaining about the way 50.44 was
                       MR. PIETRANGELO:  Right.
                       DR. WALLIS:  And you are extrapolating
           this to 50.46, but what I think I detect is that you
           realize that you have to do a lot of work on 50.46,
           and that is sort of reducing the enthusiasm a little
                       MR. PIETRANGELO:  No, I think that's why
           Adrian said there is a piece of decay heat --
                       DR. WALLIS:  Decay heat may be handable,
           but all these other things that we heard about this
           morning are not trivial.  You have to produce a really
           good piece.
                       MR. HAYMER:  Yes, and we agree that we are
           willing to sit down and produce that, but --
                       DR. WALLIS:  Well, that is what you said
           last time.
                       MR. HAYMER:  Yes, and we are willing to
           work with the staff, and we are setting up meetings. 
           But our concern is that if you see the way that 50.44
           has gone, and then if you say that is how we are going
           to go in 50.46, with the amount of work that is
           involved, that is going to be -- are we really going
           to get there.
                       And picking up on Bob's point a few
           moments ago, that's why we think it is important to
           sit down with the staff and get a better
           understanding, because we think we have the basis to
           move forward with the case, and they had a plan laid
           out of when certain work product would be produced,
           and given to the staff so they could sit down.
                       Now, the staff has come back and said that
           we need more rigor, and now we are trying to find out,
           well, we have got a program that Westinghouse and
           others are working on, and it is meant to produce
           these products in this period of time.
                       And now we are saying there is more rigor
           and now what does that mean, and it is important that
           we sit down soon and discuss what those are so that we
           can work on that.
                       MR. OSTERRIEDER:  Right, and we are not
           afraid of the new work, or the work that needs to be
           done.  What we need to do is to get it defined so that
           we understand it.
                       If it is such a massive effort, then like
           any other business decision, you have to decide if it
           is worthwhile.  But my main point is that we need to
           sit down and define the issues that we are talking
           about, and what is additional rigor, and what is an
           acceptable curve of frequency versus break size to
           support the PRA aspects.
                       We need to sit down and move on with that
           so that we can decide what the work is that we have to
           do, because we have been talking too long and we need
           more rigor.
                       And we keep saying there are a lot of
           issues and there are, but we haven't --
                       DR. WALLIS:  Well, it seems to me first of
           all that you need to have a case which is persuasive
           to you.
                       MR. OSTERRIEDER:  Yes.
                       DR. WALLIS:  And then it might be
           persuasive to somebody else, and waiting for the staff
           to tell you what that case has to be isn't really
           going to achieve very much.
                       MR. OSTERRIEDER:  Well, we believe that we
           have a case, and what we are being told is that it is
           not sufficient, and what we are trying to get from the
           staff is please help us understand what is not
           sufficient about it other than --
                       DR. WALLIS:  But you remind me of the
           student that keeps telling his professor to tell me
           what should be in my thesis, and the professor says,
           well, you know, it is up to you to figure that out.
                       MR. HAYMER:  Well, they have a series of
           work products, and a plant to develop those work
           products.  Now we are told that we have to be even
           more rigor than that, and we are saying okay, what
           more do we have to do beyond this.
                       CHAIRMAN APOSTOLAKIS:  Is the report that
           you guys are preparing for the end of June going to
           answer some of these questions?
                       MR. KURITZKY:  The report at the end of
           June is going to discuss the technical issues that we
           believe need to be resolved in order to proceed with
           the large break LOCA redefinition, and I believe as I
           said earlier that the staff has agreed to meet with
           the industry to talk in technical terms about the
           issues that have been raised.
                       CHAIRMAN APOSTOLAKIS:  Okay.
                       MR. OSTERRIEDER:  The only other comment
           on the amount of work is we are concerned a little bit
           that we are looking at such a wide variety of options
           here -- the acceptance criteria, and the different
           pieces here that we have looked at, because each of
           these in themselves could be a lot of work and to do
           the acceptance criteria.
                       And our feeling was that we should focus
           on these issues related to redefinition to define
           them, and get on with that first, versus having little
           resources to have the meetings with us and to define
           this, and do some work because there are so many
           initiatives going on.
                       And these initiatives and to do all of
           this would take many, many years we believe.
                       MR. PIETRANGELO:  And the other factor
           that was not on the table maybe in some of the earlier
           meetings on this was -- I think there was some
           miscommunication, or we weren't on the same page with
           regard to the remaining mitigation capability for the
           double ended guillotine break.
                       I think the perception was that there
           wasn't going to be mitigation capability left for
           that, and so that the approach has changed.  We do
           want to maintain mitigation capability, even for the
           double ended guillotine break.
                       But the point is that that can't be the
           design basis assumption that drives the rest of the
           other regulations where that assumption is invoked. 
           And there needs to be more talk about, well, what does
           that mitigation capability have to be, and what is the
           acceptance criteria for that.
                       Is it the same as the ones for 50.46, or
           do you keep core damage frequency below some number? 
           So there is a lot of details to be worked out, but you
           can only have one design basis on a system.  You can't
           have that this is the more likely one, and this is the
           less likely design basis.
                       That won't work in the current regulatory
           framework.  So there are issues that have to be worked
           out, but I think you have another factor there that
           can play on rigor.
                       If you have remaining mitigation
           capability for the double ended guillotine break, how
           much more rigor do you need to demonstrate to produce
           break size that is going to be the design basis.
                       So there is kind of a scale there that you
           can use to make yourself comfortable that there is
           assurance that you can handle those situations.
                       DR. WALLIS:  I still get the impression
           that there is technical work needed on both sides, and
           that is what has to be done, and just arguing about it
           is not going to resolve the positions.
                       MR. PIETRANGELO:  I think part of the
           reason this was selected was that you are building on
           things that have already been done -- leak before
           break, and risk informed ISI work.  That is all work
           that can be brought to bear on this subject.
                       So we are not starting from scratch.  We
           have gotten things that have been accepted in the
           regulatory process already, and that is a good
           foundation to go after this additional work.  So we
           are not starting from scratch.
                       DR. SHACK:  Any more questions?
                       (No audible response.)
                       CHAIRMAN APOSTOLAKIS:  All right.  Thank
           you.  I would like to also thank the staff for their
           presentations.  We will recess until 10:40.
                       (Whereupon, the meeting was recessed at
           10:20 a.m., and resumed at 11:22 a.m.)
                       CHAIRMAN APOSTOLAKIS:  The next item on
           the agenda is the potential for margin reductions
           associated with power uprates, and this is Dr. Wallis
           and Dr. Bonaca.
                       DR. WALLIS:  I would simply say that you
           all know that we are interested in this issue, and you
           all know Gus, and we are looking forward to what he
           has to tell us.
                       CHAIRMAN APOSTOLAKIS:  Dr. Bonaca.  Okay,
                       DR. CRONENBERG:  This is basically a
           status report on some work that I have been doing that
           came out of the retreat.  So I started this in March,
           and I titled it, "Signature Estimates of Margin
           Reductions," because I think we have bits and pieces
           of information, and sort of sign posts, but it is not
           the full story.
                       In the outline of my talk, I am going to
           give you a little bit of how margins is used in the
           regulatory process, and then I am going to give you
           some estimates of what I was able to find for a case
           study that I did for the Hatch plant.
                       Hatch had two prior power uprates and is
           under present review for license renewal.  So I will
           do the power uprates, and then some estimates from
           basically time limited aging analysis for the Hatch
           plant, and then some preliminary findings.
                       DR. KRESS:  Are those bullets little land
           mines or what are they?
                       DR. CRONENBERG:  They are something or
                       DR. LEITCH:  Gus, the status report that
           we got, is that what you are referring to, or is that
           -- I guess what I am saying is some of the chapters
           here seem to be not aligned with --
                       DR. CRONENBERG:  Yes.  That is just a
           draft of --
                       DR. LEITCH:  It is just a draft?
                       DR. CRONENBERG:  Yes, the end product is
           in September, and I want to give you a final report on
           this study, and that is just where I am on what I have
           to date.  It is a little disjointed, but I just wanted
           to show you where I am going.
                       And so that report will be in a final form
           in September when I intend to wrap this project up.
                       DR. LEITCH:  Okay.  Off-line then, I will
           give you a couple of comments here after just reading
           through this.
                       DR. CRONENBERG:  That's fine.
                       DR. LEITCH:  Editorial type of things.
                       DR. CRONENBERG:  Yes, okay.  And then you
           also have in your notebook like a four page summary of
           what we did and where we are at.  Okay.  Margins, from
           Webster, are as spare amount allowed for contingencies
           or another definition of bare minimum below which
           something is no longer desirable.
                       DR. WALLIS:  It's marginally, you mean? 
           You mean marginal performance on a test or something
           like that?
                       DR. CRONENBERG:  Yes.  Well, you
                       DR. WALLIS:  Well, you go to Webster, and
           in fact the agency doesn't define what it means by
                       DR. CRONENBERG:  Margin is used in a
           rather general sense, and what I did was go to the
           general design criteria and just try to give you
           examples of how margin is used in the general design
                       And then actually you have to go to
           regulatory guidance, and you have to go to ASME
           pressure and pressure vessel, or code, or American
           Institute of Standards type of thing to really look at
                       For example, Criterion 10.  It says that
           the reactor core and the associated cooling control
           and protection systems shall be designed with
           sufficient margin to assure acceptable design limits
           shall not be exceeded.
                       Well, Graham, you might say, well, that
           doesn't tell me anything, and it might be the kind of
           thing that we would expect from Graham.  This exactly
           how -- and it goes on and on.  They are all like that. 
                       Criterion 31, the reactor coolant pressure
           boundary shall be designed with sufficient margin,
           blah, blah, blah, so that it behaves in a non-brittle
           manner.  Again, it doesn't tell you.  You have to go
           a step further, and that is coming in the next few
                       Criterion 50, the containment.  Now, not
           only the primary system, but the containment,
           including openings, penetration, shall be designed
           without exceeding a design leakage rate, and with
           sufficient margin to reflect metal, water, and
           chemical reactions.
                       DR. WALLIS:  Doesn't sufficient margin
           relate to uncertainty in all of these things?
                       CHAIRMAN APOSTOLAKIS:  Yes.  Sure.
                       DR. WALLIS:  It is tied in with
           uncertainty, but that connection isn't explicitly
                       DR. CRONENBERG:  These are general design
                       DR. POWERS:  I think you would end up with
           confusion if it made that tie, because the margins are
           there for the things that are not included in the
           analyses that are typically done.
                       CHAIRMAN APOSTOLAKIS:  Not necessarily. 
           If you are uncertain about something, you don't know
           what the value would be.
                       DR. POWERS:  These are Chapter 15
           analyses, George.
                       CHAIRMAN APOSTOLAKIS:  Oh, oh, okay. 
           Thank you.
                       DR. POWERS:  And there are things that you
           may not know.
                       CHAIRMAN APOSTOLAKIS:  That is what it
           should be, yes.
                       DR. POWERS:  And that nobody thought of,
           and so those margins are things that are not taken
           into account.
                       CHAIRMAN APOSTOLAKIS:  But how can you do
                       DR. WALLIS:  Then this is just a gut
           feeling then, and if you don't know what they are,
           then you can't assess them.  You have to make some
           sort of a guess as to what they are.
                       DR. POWERS:  You've got it.
                       DR. WALLIS:  And so margins are just
           guesses about how unsure you might be.
                       DR. CRONENBERG:  Well, for example, it
           will say that you can't exceed -- that a pipe can't
           exceed a design pressure of a thousand psi.  The
           licensee will come and say my LOCA now shows that this
           steamline for design basis accident gets to 950 psi. 
           I have a 50 psi margin.
                       The licensee will say that to me is
           sufficient margin to meet --
                       DR. WALLIS:  But your uncertainty in your
           prediction is plus or minus a hundred, and therefore
           I am not going to --
                       VICE CHAIRMAN BONACA:  They would come
           back and say that we have built in considerations for
           uncertainties for the conservatism.  Now, to negotiate
           whether those conservatism would in part account for
           uncertainty or not.
                       DR. WALLIS:  Well, you can't be so wishy-
           washy about it.
                       DR. POWERS:  Graham, in no case would you
           come in and say the uncertainty in your calculations
           here is plus or minus anything.  You would always be
           that your uncertainty in this is plus X, minus
           nothing, because they are conservative calculations.
                       DR. CRONENBERG:  Okay.  That's -- we are
           going top down.  It starts with the general design
           criteria, where margin is first, and that is the rule
           of law.  It says that you have to have sufficient
           margin, and it doesn't define in psi what that margin
           is, or percent, to some limit.
                       You have to go to a regulatory guidance,
           and even there the regulatory guidance usually refers
           to, let's say, the ASME pressure and pressure vessel
                       But it will give you acceptance criteria
           for design pressures, pressure temperature limits,
           stress limits, allowable materials, ductility limits. 
           Those are the kinds of requirements that will be
           placed on certain system structures and components --
           a piece of pipe or whatever.
                       And basically it will then say go to the
           ASME pressure vessel code, and then the ASME pressure
           vessel code will tell you more detail.  It will tell
           you how you have to test, and how you have to remedial
           this material if you are going to us the thickness of
           this material with that alloy and composition.
                       And that this is the pressure that you
           cannot exceed, and that is how it is all established,
           and that is how we establish design criteria.  We
           build upon code upon code.
                       DR. WALLIS:  I am puzzled about what Dana
           said about having no error in the other direction, and
           if it is a conservative analysis, why do you need a
           margin if there is no error output?
                       DR. POWERS:  It is put in there because
           you may not have thought of everything.  These are
           complicated systems, and at the time they were built
           they didn't know what --
                       DR. WALLIS:  So it is an illusory to say
           there is no error in your conservative analysis?
                       DR. POWERS:  Well, there are presumably
           things that get discovered all the time.  One of the
           reasons to put margin in there for is that the coding
           analyses tells you how the thing is built, and as soon
           as it is built, it starts degrading.
                       And it degrades in ways that may not be
           reflected in things like corrosion allowances and
           stuff like that.
                       DR. CRONENBERG:  And in the ASME code,
           there is margin for design limits that will take into
           account aging and rusting of field components and
           those sort of things.
                       Those already have margins, and the way
           that I am going to estimate margin is that I am going
           to say that this is the ASME design limit for this
           particular pipe, and how close are we to that design
                       There is margin above that, too, that is
           supposedly built in, and if you test it right, and if
           you subjected this material to the kinds of
           environment that it was tested for.  Sometimes, of
           course, we have stress corrosion cracking, and those
           sort of things that aren't in there, or irradiation.
                       We had a lot of things added to the
           pressure vessel code and to the irradiation
           embrittlement, and that sort of thing over time.
                       VICE CHAIRMAN BONACA:  But even when you
           talk about degradation -- for example, from corrosion
           in vessels, even there, there are limits to how much
           you accounted for.  It's not that it is a indefinite
           process of corrosion that lasts forever.
                       I mean, it is not a time limit as others,
           but there were certain assumptions made which was
           essentially limits of the acceptability to
                       DR. CRONENBERG:  I am going to show you
           examples of this.  Probably the best education is via
           an example here.  Let me go on.  The first thing that
           I wanted to look at is the impact of power uprates,
           and changes in operating conditions, a change in
           design basis accident conditions for increased
           coolant, and that you have already associated with the
           power uprate.
                       And you will have changes in primary
           system conditions, and you will have changes in
           secondary size steam generator flow rates, and feed
           water flow rates, and you will have changes in coolant
           and temperature, and flow rates and that sort of
                       Those are the kinds of things that are
           changed with power uprates.  Here is some current
           power uprate applications.  We have the Duane Arnold,
           15 percent; and the  Dresden plan, and the Quad
           Cities, Brunswick, Clinton, and we have Arkansas 1,
           and a PWR, and significant power uprates.
                       We are not talking now these days about 5
           percent, or 3 percent uprates.  We are talking major
           uprates, and I guess in the conference yesterday they
           were talking about 10,000 megawatts of electrical
           generation, like building 10 new plants from power
                       So we are talking about a major activity
           here and a major responsibility of the ACRS.  We are
           also talking about plants that are pushing 30 years
           old; mid-'70s, and vintage 25 or 30 years old.
                       So we are not talking about uprates, but
           we are talking about uprates to an age depletive
                       DR. WALLIS:  And some of these plants had
           a power uprate before, because perhaps they were
           operating conservatively initially or something.  I
           think some of them actually had a power uprate before
           of a much smaller amount.
                       DR. CRONENBERG:  The way I read this is
           that these keep coming in.  I don't know if they will
           ever be an advanced light water reactor.  I don't know
           if they will ever be what you were talking about
                       But this train is already leaving the
           station, you know, on the uprates.  So your concern
           about margins, I think, is a very timely, timely
           subject at this point.
                       DR. WALLIS:  The references that you made
           in your earlier report about --
                       DR. CRONENBERG:  I am not talking about --
           well, on Tuesday, there is a thermal hydraulics
           meeting, and I intend to go back over that if Graham
                       We will look at operational experience
           from prior uprated plants and what I found there
           besides this talk today.  So I plan to give both
           talks, but not today.
                       DR. WALLIS:  You will be there on Tuesday?
                       DR. CRONENBERG:  Yes.
                       CHAIRMAN APOSTOLAKIS:  Just one note.  I
           mean, many of the PWRs are not listed here, and they
           went through the five percent, but they were really
           designed originally, and even the accident analysis in
           the FSAR was done at the construction stage of the
           higher power level, and they were really operating at
           95 percent power like this or whatever.
                       So that is not really a power uprates.  It
           is something that was designed to be that way.  These
           are substantial power uprates.
                       DR. CRONENBERG:  Those are what are called
           power stretches, I guess, in the G.E. vernacular. 
           Okay.  I did a case study for the Hatch case, because
           that is on the plant renewal, and it had two prior
           uprates.  It is a G.E. BWR/4 direct cycle plant.  It
           is an early '70s vintage plant.
                       It had a power -- it is a two unit plant,
           and sister units, and the same power generation from
           each unit.  It is originally a 2,400 megawatts and
           then to 2,500, and then to 2,700.  And it is now on to
           license renewal.
                       And Monticello had or was sort of case
           studies for the G.E. guidance on power uprates.
                       DR. LEITCH:  Gus, one of the things that
           concerned me about the Hatch situation, but I don't
           think it appears on your slide though and on your
           paper, but it talks about the stress increase in the
           access hole cover plate.
                       And it is really quite appreciable.  I
           mean, most of the rest of them are kind of what you
           would --
                       DR. CRONENBERG:  I am going to get to
           that, to the cover plate story.
                       DR. LEITCH:  You are going to talk about
                       DR. CRONENBERG:  Yes.
                       DR. LEITCH:  Okay.  Great.
                       DR. CRONENBERG:  This is just a sketch or
           a schematic of the direct cycle G.E. plant, and we are
           going to look at, for example, what the design
           pressure for the main steam line is, and the design
           pressure for the feed water system, and the design
           pressures for the piping and the research evasion
                       We are going to march around this plant
           and look at some design limits, and then some
           calculated pressures and temperatures, and we are
           going to look at some time aging analysis for piping
           and that sort of thing.
                       So wherever I could glean some information
           that is how I estimated margin.  Okay.  Here is a
           summary of the uprate conditions for the Hatch, Units
           1 and 2, and the years; 5 percent uprate, and then 8
           percent, both of which change in operating system
           conditions.  So these are operating conditions.
                       As you can see, steam flows get higher
           with uprate, and design pressure got higher on the
           first, and the steam dome pressure got higher on the
           first uprate, but remained the same for the second
                       The dome temperature, the steam dome
           temperatures got higher on the first uprate, but not
           for the second.  Feed water supply always is increased
           and feed water temperature is a little bit for each of
           these uprates.
                       So these are some operating conditions and
           then we will look at what the design limits are for
           the temperature and pressure for those kinds of
           operating conditions on various piping.
                       Basically what I said is what -- okay.  We
           just saw from the general criteria that there was no
           definition of what margin is.  It just is that there
           shall be sufficient margin.
                       And so I said I will make -- this is my
           definition of margin, and it will be the design limit
           that is in a code, the ASME pressure vessel code, and
           the value over the design limits, and how close we get
           to the design limit.
                       So here we look at the main steam line
           pressure and the design limit for that piping is 1,250
           psi.  And the original was 1,015.  So we had an 18
           percent margin to the design limit.
                       Then we went on the first uprate and the
           pressure increased to 1,050.  So we dropped down to 16
           percent between the value of the operating condition
           and the ASME allowable pressure for that type of
                       And the same thing with steam line
           temperatures.  There is a design limit for that pipe
           of   575 degrees F.  We increased -- and sometimes I
           could not get the information, and I want to talk
           about that a little later, too.
                       The difficulty of getting information,
           especially design basis calculational information, and
           trying to retrieve historical data and historical
           calculations to get the changes in margins over time.
                       DR. WALLIS:  We are supposed to have
           adequate margin, and I just can't quite grasp how we
           decide what is adequate.  Is 16 percent adequate, and
           would 12 percent have been accurate?  Would 5 percent
           have been adequate?  How do we know?
                       DR. CRONENBERG:  Let me say that I am not
           answering that question.  That is a question before
           the committee, the commission, the staff.
                       DR. WALLIS:  Do you have any guidance
           about how we can decide whether it is a reasonable
           margin or not?
                       DR. CRONENBERG:  Let me go on and then I
           will come back.
                       DR. SIEBER:  It is really not that easy,
           because part of the margin is to accommodate
           transient, and so you have to know what the transient
           response for the plan is.
                       DR. CRONENBERG:  The real degradation in
           margin is in your calculations for your design basis
           event.  An 8 percent could make a 20 percent
           difference in a load to a pipe, okay?
                       VICE CHAIRMAN BONACA:  And I think that
           Gus has a good example on that, that we can use to
           discuss this very issue, because the question will
           then come on that issue that -- and when we get to
           that issue, we can talk about it.
                       DR. SHACK:  Well, from the code point of
           view, it would be 1,250 gives you adequate margin.
                       VICE CHAIRMAN BONACA:  That is correct.
                       DR. WALLIS:  But there is already the
           margin in that.
                       DR. SHACK:  Right.  There is the code
           design limit provides what they believe is adequate
                       DR. SHACK:  That's right.
                       VICE CHAIRMAN BONACA:  And the degree to
           which you can show that, for example, that as the
           plant ages, that you still have a value of 1,250.
                       CHAIRMAN APOSTOLAKIS:  So this is
           additional margin.
                       DR. SHACK:  It is a code margin, that's
                       DR. WALLIS:  And this is one of the
           debates; who does it belong to and all of that.  I
           think it would be very good if we could be clear do we
           need any margin beyond what is already in the design
           limit margin.
                       CHAIRMAN APOSTOLAKIS:  Well, that is not
           what he is addressing now.
                       DR. SHACK:  Assuming there is no defects,
           and that is a good point.
                       DR. WALLIS:  There are always defects.
                       DR. SHACK:  The code is part of the reason
           that it is in fact lower --
                       DR. CRONENBERG:  The value point or the
           yield --
                       VICE CHAIRMAN BONACA:  You may remember,
           for example, on the primary side that the whole debate
           in 50.59 for what the value documented in the FSAR
           versus a set limit.
                       And the industry position was that from 
           the set limit up it is my margin, or below is our
           margin, and above is your margin.  And the position of
           the NRC is that we want to control also the margin
           between the maximum value that you have in your FSAR
           and the set limit because it is a margin.  So that is
           still debated.
                       DR. CRONENBERG:  Okay.  The last
           presentation was not surprising with the change in
           LOCA.  If you want to go into significant power
           uprates, that is maybe where you had better or you
           could see, because as I will show you in the next
           couple of slides, when you look at margins for design
           basis events, they are decreased rather dramatically.
                       DR. WALLIS:  What I am trying to grasp is
           what is the criterion for deciding when you stop?  Is
           it when you cross the design limit or something, or
           what is the criterion for limiting uprates?
                       DR. CRONENBERG:  You will have to ask the
           staff on Tuesday.  We have no standard review plan. 
           If we had a standard review plan, we might have
           specified acceptance criteria for uprates.
                       And I have been talking about that point
           for a few years now, and I will talk about it again on
           Tuesday.  Here is some more feed water piping where
           actually the feed water pressure went down on the
           second uprate.
                       So the residual margin was increased, but
           the real story here I think is what happened with --
           that each time you come for a power uprate, you have
           to recalculate your design basis accident conditions,
           and that is a good part of the safety analysis report
           that accompanies a license amendment request for an
                       And these are design basis LOCA loads for
           -- well, this is the pressure vessel, and in the
           original the load was estimated at 8.9 kilopounds per
           square inch, and the design limit is 15.
                       DR. WALLIS:  Just remind me that these are
           forces due to momentum effects during a LOCA?
                       DR. CRONENBERG:  Yes.  These are forces on
           piping during a LOCA.
                       DR. WALLIS: So you have to have a good
           momentum equation to predict them?
                       DR. CRONENBERG:  Yes.
                       DR. SIEBER:  Or a water margin.
                       DR. CRONENBERG:  Okay.  And the first
           uprate, the prediction is nine.  So you have a little
           -- you decrease your margin a little bit.  The vessel
           shroud, and this is stress calculations.
                       One thing that was hard to do when you
           chartered me to look at what this reduction in margin
           is, you can only get results for little bits and
           pieces of components in the system.
                       You don't have an ISO stress figures for
           that margin of time for the LOCA.  You will have a
           summary table saying here is the stress on a bulk, and
           here is the stress on a weld, and here is the maximum
           stress during the LOCA, and that's all.
                       And that will be an appendix usually to
           the SAR, and it is usually for a G.E. applicant, and
           it will be G.G. proprietary information, and all it
           will be is these five numbers of various stresses.
                       So it is hard to get a real good
           comprehensive feel for what is going on, and it will
           change with time.  One operator will give you the
           stress on a bolt, and the other one will give you the
           stress on a weld.
                       The other one will be stress on a plate or
           the pipe itself.  So you can't get a good feel for
           what is happening with time for just even one
           component.  You can see there is blanks in here.
                       You would rather see a better picture.  So
           if you guys are serious about requesting the staff to
           estimate margin reductions for power uprates, where
           are they going to get the information when they get
           summary reports?  And how are they going to retrieve
           this information that is 10 years old?
                       CHAIRMAN APOSTOLAKIS:  We are trying to
           get a feeling right now for what the issues are.  So
           I think you are going in the right direction.
                       DR. CRONENBERG:  Well, I just wanted to
           bring that out to you.  It was not easy to find the
           information, and some of the information on the
           license renewal, I had to request from the applicant
           itself.  It wasn't even in the agency.
                       And I will go on, but anyway, you see a
           general trend of margin reduction for increased power
           uprate, and here is this access cover plate.
                       DR. LEITCH:  And that is exactly the point
           that I wanted to address.  That seems to be kind of
           counterintuitive there, that large reduction in
                       And I wonder if we are really comparing
           apples and apples, because it seems to me that in
           about 1990 or so -- I don't remember the exact time
           period -- that access cover plate had some problems
           and was redesigned.
                       DR. CRONENBERG:  Yes.
                       DR. LEITCH:  And I was just wondering if
           those stresses --
                       DR. CRONENBERG:  These are the two
           stresses.  These are numbers that I took from the G.E.
           appendix to the license amendment request for the
           uprate, and it was on the same bolting.  Now, that
           access cover plate was replaced.
                       These are again to the design as to 107.7,
           and this is an 8 percent power increase that you had
           over a 20 percent reduction in margin for the 8
           percent.  The lows were significant, a significant
           jump in loads from 60 to 90.
                       Now, that access cover plate is what they
           found in Peach Bottom, a sister type of plant, was
           that they had stress corrosion cracking in Peach
           Bottom, and NRC required that that access cover plate
           be replaced.
                       Hatch did -- all sister plants had to do 
           ultrasonic testing on theirs following shutdown, and
           do ultrasonic testing.  They found evidence of
           cracking on their cover plate, but they could neither
           confirm or deny how deep that cracking was.
                       NRC dictated that they put in a monitoring
           program to monitor those welds, and they decided to
           just preempt the problem and replace those cover
           plates on Hatch because of what was confirmed at Peach
           Bottom, but never really confirmed at Hatch.
                       They just replaced the cover plate, but
           what is happening here is that Peach Bottom did have
           confirmation of significant stress corrosion cracking,
           and probably that design limit was not retained.  And
           I am always comparing it to design.
                       VICE CHAIRMAN BONACA:  And I think this is
           a good example because -- and we brought it up with
           the staff already.  The staff was asking what kind of
           questions do you want us to ask, and the questions, if
           you have aging, that may challenge in fact the design
           limit of 107 KSI because of the degradation that is
           resulting as a part of aging.
                       The question is do you still have the
           margin between 90 KSI and 107, and you probably don't. 
           As a minimum, the uncertainty is very much in
           question, because you have only 16.4 percent of
           margin.  So that was simply an observation that as a
           minimum, in reviewing the power uprates, the reviewer
           should not just simply compare a apple with an apple. 
                       They should ask some questions regarding
           the operating history, and the inspections done, and
           what is happening to the plant, because the plant is
           aging, and it is a fact.  So that is just one point
           that I wanted to make that we brought up with this
                       DR. CRONENBERG:  But most of the time in
           the license application, they will just quote we have
           this limit to our design, and this much margin to our
           design limit.
                       I have not seen the kind of discussions
           that Mario was talking about in a license application.
                       CHAIRMAN APOSTOLAKIS:  You have not really
           addressed the strength here.  You are just saying that
           as a design limit and calculations show that the
           predicted strength is this, but you are not saying
           anything about how or what is happening to the design
           limit today.
                       DR. CRONENBERG:  Well, that does come in
           the aging, but these are all numbers that I got from
           a licensed application.  I am comparing that this is
           the licensee's numbers, and this is the degradation in
           margins based upon the licensee's own numbers.
                       And I was hoping that I could get more
           information, and I found it rather confusing because
           we never say you shall give me -- if we had a more
           structured approach to operate, you shall give me
           these stresses for these bolts, for these pumps, for
           this pipe weld, for that access weld, so I can compare
           in time what is happening as I uprate the power.
                       The story to me is confusing because we
           don't have a rigorous approach to how we review power
           uprates, and so --
                       CHAIRMAN APOSTOLAKIS:  But this is really
           the residual additional margin, right?  Wouldn't that
           be more accurate, because there is already a design
                       DR. CRONENBERG:  I gave you my definition
           of what I am using as margin.
                       CHAIRMAN APOSTOLAKIS:  But I think if you
           put the word additional there --
                       DR. POWERS:  Residual he calls it.
                       CHAIRMAN APOSTOLAKIS:  The concern here
           was, and as we expressed before, was that when you go
           with power uprate, the project engineer goes through
           a checklist, but especially uprating plants that have
           been running for 20 years or 30 years, there is a
           history behind which involves aging, irrespective of
           license renewal.
                       VICE CHAIRMAN BONACA:  Is it adequate to
           simply go back --
                       DR. SHACK:  But again if he had any known
           cracking, he would be operating under a different set
           of rules.  That is, that he would have to account for
           the crack, the crack size, and he would have limits on
                       VICE CHAIRMAN BONACA:  I don't deny that
           there are considerations like that, but I am only
           saying that until now it seems to me -- and what Gus
           has pointed out -- that without a specific more
           thorough checklist almost of how you are going to do
           it, it would be purely checking a number against a
                       And if you have a residual margin of one,
           it is enough to say yes, and the point that Graham was
           raising before.  And I think there has to be a more
           thoughtful review given that you have an operating
           history behind it.
                       CHAIRMAN APOSTOLAKIS:  But you can't just
           look at the incidents of aging, because there are also
           inspection programs, corrective actions, and so all of
           those have to come in, and so the assumption here is
           I guess, but unless there is evidence of something
           going on, the design limit is preserved.
                       VICE CHAIRMAN BONACA:  Absolutely, and I
           am not denying that, but I am only saying that we are
           checking to see what kind of margins there are, and
           how they are reduced, and the significance of those,
           and the fact that as you get very close -- I mean,
           originally they started with a blowdown pressure of
           stress with a component of 64.5 KSI.  That was the
           original design.  And the design was actually 107.7,
           and a 40 percent margin, and so --
                       DR. CRONENBERG:  That was on the first
           uprate, and I don't even know what -- I couldn't find
           it in the FSAR what it was on that bolt.
                       DR. LEITCH:  But, Gus, that is the one
           -- in all of this data, that is the one thing to me
           that is surprising, and almost counterintuitive, that
           it would change that much.
                       And I guess what I am saying is that there
           has been some redesign work done down there on that
           access cover, and I am just wondering whether these
           numbers are presenting the correct story, or whether
           the numbers somehow got skewed by reanalysis,
                       DR. CRONENBERG:  Which number are you
           talking about, the design limit or the calculated
                       DR. LEITCH:  No, the design limit.  I am
           saying that maybe they went back and after finding
           this problem at Peach Bottom, they might have gone
           back and said, oops, maybe we had better recalculate
           that 64.3, and maybe they found out it was 88 or
           something like that.
                       And what we are saying is a significant
           reduction in margin due to power uprate may be due to
           something totally different than that.  I am just
           surprised that that order of magnitude of change.
                       The rest of the changes almost seem
           intuitive to me, and I just want to be sure that that
           one piece of data isn't taken as --
                       DR. CRONENBERG:  That was just a number. 
           We get summary reports, and we don't get detailed on
           what boundary conditions are on codes, and what
           stresses are predicted, a time line.  We just get a
           summary table.  I am going to show you the kind of
           information that we get in an application.
                       DR. LEITCH:  Yes, but all I am saying is
           that I don't understand the phenomena that would
           increase the stresses on those bolts by that much by
           just --
                       DR. KRESS:  It is strictly the pressure
           doing that, and the pressure didn't change that much. 
           I think you are right.  There is something wrong
                       DR. LEITCH:  Yes.  I just don't want to
           focus on that question and --
                       DR. CRONENBERG:  Well, it is coolant and
           higher flow rates, and --
                       DR. KRESS:  But that is a lot of change.
                       DR. CRONENBERG:  Well, this is in the
           application, and these are reported numbers, and none
           of these are anything else but reported numbers.
                       CHAIRMAN APOSTOLAKIS:  I think you made a
           good point, and we should be cautious about that.
                       DR. CRONENBERG:  Okay.  Here is some of
           the containment again, and this is an inverted light
           bulb type of BWR, and we can see that the pressures
           there are going up and the drywell or the margin is
           going down.
                       And the peak drywell gas temperatures are
           exceeded for a small time.  However, it is only for a
           short time.  So that was allowed.  And then the design
           limit, and the suppression pool temperatures, and the
           design limit is 281, and we go from 198 to 202, to
           208.  We keep creeping up as we might expect the
           margin to design limit goes down.
                       DR. KRESS:  Should we be concerned about
           all these decreasing margins?
                       DR. CRONENBERG:  Well, let me get to the
           end, and let me talk about a more holistic or
           conclusion.  We also have signatures of margins for
           license renewal, and most of that was gleaned from
           looking at the time limited aging analysis.
                       And basically that comes out of appendix
           material for the Hatch, and this was surprising to me
           that we had discussions of the accumulative usage
           factors, and estimates of those cumulative usage
           factors for various components for the Taurus, for the
                       But that was information that I couldn't
           get from the staff here.  I had to go back to the
           licensee and the licensee had to request from G.E.,
           and G.E. has a structural associate contractor that
           G.E. uses to do this cumulative -- essentially fatigue
                       So you really had to go back and reference
           it, and it wasn't in the agency where I got these
           numbers.  I had to get it from the licensee, and Mario
           saw all the E-mails back and forth to retrieve this
                       So it is not just something that -- well,
           you have got to work at getting it if you want to look
           at margins.  Okay.  This is a cumulative usage factor,
           and it is basically a fatigue estimate for various
                       And they estimated for 40 years for the
           end of the first renewal, and they gave estimates for
           the license renewal period of 60 years.  Basically,
           they keep track of the number of SCRAMs, and the
           number of bolt up and bolt down operations, and
           anything that can fatigue a particular component, any
           minor seismic events.
                       And if you exceed one, then you exceeded
           the allowable fatigue limit for that particular
           component.  So you estimate these things, but a lot of
           this is based on historical data.   You have got to
           keep track of SCRAMing, SCRAMs, and bolt ups, and bolt
           downs, and that sort of thing.
                       So the cumulative usage factor,
           essentially you are going to one.  The design limit
           here is one.  If you exceed the design limit, then you
           have to negotiate something with NRC, whether the
           surveillance has to be higher surveillance, or that
           component has to be replaced, or whatever.
                       The suction piping, the cumulative usage
           estimate for that is 57 at 40 years, and it goes up to
           77 at 60 years.
                       CHAIRMAN APOSTOLAKIS:  Again, let me
           understand this.  Does this include the impact of
           inspections and corrective actions?
                       DR. CRONENBERG:  No, this is just an
           estimate of how close to a fatigue limit you might
           have been if you had 35 SCRAMs, a combination of 35
           SCRAMs, 60 head removals, a seismic event.
                       DR. SHACK:  And we don't even know if
           these are calculated based on actual cycles or some
           projected design cycle?
                       DR. CRONENBERG:  It is a combination. 
           When you look at them, they do have tables of historic
           data for the SCRAMs, and then they estimated what it
           is going to be in the future, and that is how they get
           it to 40, and that's how they get to 60.
                       It is a combination of historical data and
           estimates.  I think it is a pretty nice analysis.  I
           thought this was -- I thought this was somebody trying
           to estimate margins, you know.
                       And it is for various things that you have
           said, because you have a standard review plan for
           license renewal, and you say you will do these kinds
           of estimates on these kinds of components.  And then
           you can begin to see, well, at least there is an
           estimate of margin here.
                       DR. FORD:  On a procedural aspect, for
           instance, the piping.  This is based on a code
           analysis, which takes into account normal fatigue and
           corrosion, but it does not take into account, however,
           corrupting, and corrosion would be an additional
           effect.  How is that taken into account?
                       DR. CRONENBERG:  That is a good point.  As
           far as I can tell from looking at these contractor
           reports, it is assumed that same power for the next 20
           year cycle, and I did not see something in here that
           related to if you had added on top of it a power
                       Just that you had so many bolting
           operations, and so many SCRAMs at power.  So I can't 
           be sure, but I would have to go back into this.
                       DR. FORD:  Well, maybe I am asking a
           question where there is no way of knowing the answer,
           but how would the staff address the degradation mode
           on this --
                       DR. CRONENBERG:  This kind of thing never
           comes up in an uprate.  You don't have -- usage factor
           estimates in the power uprate.  Those are time limited
           aging analysis, and that is what the whole -- Mario
           and some of your concerns are.
                       We don't look at licensing of a plant in
           a holistic sense.  We look at one licensing action and
           make a judgment.  We will get another licensing action
           and make a judgment, and we will look at fuel
           replacement and we make a judgment.
                       But we don't make or you don't have to
           have legacy tables in here, where I did this to my
           system, and I did that, and this was an uprate, and
           this was a license renewal, and this was a fuel
           change, and these are the changes in design basis
           loads for all these changes.
                       Maybe somebody has, but I can't glean that
           kind of information from any of these reports on the
           legacy of this plant and all the changes that have
           been made, and how it impacts margin.  We review
           separate licensing actions.
                       DR. SHACK:  Peter's direct question, and
           I think they would argue do the code analysis, with a
           very small thinning requirement allowance in the code,
           which is done independently --
                       DR. FORD:  So the worst --
                       DR. SHACK:  That is the only way the flow
           assisted corrosion affects the CUF, and there is no
           other thing, but then you would address the flow
           assisted corrosion separately.
                       DR. FORD:  Separate and take the worst
                       DR. SHACK:  Yes.  You would have to
           demonstrate that you weren't violating any of your
           code limits on thinning.
                       DR. SIEBER:  Well, there is actually 
           margin built into the manufactured product, because
           the code says here is the minimum wall, and when you
           go and buy a new one, it is thicker.
                       DR. WALLIS:  George, we are due back here
           at 1:15 after lunch, and that is a fixed time isn't
           it?  So we have to move along.
                       CHAIRMAN APOSTOLAKIS:  Yes, and there is
           also a separate meeting in 10 minutes.
                       DR. CRONENBERG:  Okay.  Do you want me to
           wrap this up?  okay.
                       CHAIRMAN APOSTOLAKIS:  Okay.  Why don't
           you go to the conclusions, and summary and
                       DR. CRONENBERG:  Okay.  Margin estimates. 
           Again, I talked about not getting or having to go
           through lots of steps to get numbers.  This
           information is not readily available as far as I can
                       And I tried to tell you that we get
           summary reports in the license applications.  We don't
           -- if you want margin estimates for a plant, you are
           going to have more than just I got it for this bolt
           and this piece of pipe, and that's all I am going to
           give you.  There is not a lot of information.
                       And summary and observations.  Safety
           margins is used in a broad sense in the regulatory
           process, and we have already talked about this.  There
           is a lot of difficulty in getting self-consistent data
           for an assessment of margin impact.
                       Not only do you get it for different
           components, but calculational codes change, and
           calculational procedures change for LOCA.  You are
           already talking about major calculational changes for
                       So it is hard to get an apples and apples
           comparison.  Nevertheless, I think that we had some
           success for this case study for Hatch.  We were able
           to estimate from the licensee's own number some
           signatures of margin reductions, and it looks like
           there is always some margin reductions for various
                       DR. WALLIS:  And it is not particularly as
           severe, except for these bolts and that may be --
                       DR. CRONENBERG:  Yes, but we have not
           looked at it integrated.  I have given you bits and
           pieces of information, too.  I never put it all
                       To me, the SARs and the SERs do not appear
           to have information of sufficient detail or
           consistency for any in-depth quantitative assessment
           of margin info for multiple licensing actions.
                       I don't think we have the kind of
           information from the SARs and SERs, and the type of
           information requirements that we have to date.
                       Uprate review.  Again, I want to endorse
           the prior recommendations for a standard review plan. 
           I have been talking about this, and you have other
           studies in this agency.  The Maine Yankee lessons
           learned says why don't you have a standard review plan
           for uprates, and it would probably be better if there
           was a scientific study of power uprates from the early
                       And it came to the same conclusion.  It is
           an ad hoc sort of process that is not in place, and I
           think the agency would be better served if we had a
           standard review plan, especially when we are talking
           about the power uprates that we are talking about; 20
           percent for an aged fleet of plants.
                       And it also came from my own review of
           operational events for operated plants.  I had some
           suggestions on what could be included in a standard
           review plan, and it goes on from there.  I think I can
           wrap it up.
                       CHAIRMAN APOSTOLAKIS:  Okay.  Thank you.
                       DR. LEITCH:  Just one question.  I thought
           that one of the effects that we were going to look at
           is increased fuel burn up, and I don't see anything
           about that here.
                       In other words, in addition to power 
           uprates and license renewal, I thought that one of the
           other major things was increased fuel burn up.  And I
           just wondered if you planned to take a look at that
                       In other words, is that coming along in
           the future?  Are you saying what we have here is just
           a preliminary draft?
                       DR. CRONENBERG:  I don't think I am going
           to be able to get to it.  I think I have about 6 weeks
           left in my time, and I want to wrap up what I have
           done in a coherent paper report.  So this project ends
           in September, and I work half-time.
                       So I don't plan to do anything on fuels or
           another plant, or anything else.  I just wanted to
           give you a report and I wanted to give you a 10 page
           summary paper if somebody wants to publish it.
                       And I also want to do the same on a prior
           study that I did for operational events.  I want to
           write a 10 page summary and leave it with some of you
           guys to publish it.
                       DR. LARKINS:  Gus, is there any -- do you
           have reason to believe that there may be information
           out there that if someone were to follow on to this
           activity, this project, to do something in this area
           additionally, like high burn up fuels?
                       DR. CRONENBERG:  Yes, I think you could.
           You have got to delve into it, and yes, there is
           corrosion limits, and irradiation, and brittlement on
           control rods that march on with time.
                       DR. LARKINS:  One of the things that I am
           getting at, and one of the things that you might want
           to do in finalizing your report is to make some
           recommendations for any follow-on activities.
                       DR. CRONENBERG:  Sure.  Sure.
                       VICE CHAIRMAN BONACA:  Are you going to
           look at some of the PRA aspects that we discussed
                       DR. CRONENBERG:  I am going to try to, but
           basically you know what is in PRA.  You don't reach
           your design limits, and you march on.  You don't fail
                       DR. WALLIS:  I am trying to grasp what the
           ACRS should do on this, and we have a meeting on
           Tuesday about uprates, and are we expected to write a
           letter for July on power uprates or are we just sort
           of learning as we go along, and eventually we will
           have to do that.
                       VICE CHAIRMAN BONACA:  I think we are
                       CHAIRMAN APOSTOLAKIS:  At this point, we
           are learning.
                       MR. ELLIOTT:  I think that would be up to
           you guys, depending on what you hear at the
           subcommittee meeting.  One thing to note is that back
           in December when you discussed this issue last time,
           the research people came in and said that they were
           proposing to look at the issue of synergism that Gus
           has raised here.
                       But they said that they had no funding,
           and what you are going to hear Tuesday is now that
           they do have funding, starting in FY '02.  So you may
           want to think about commenting on that, depending on
           what he has to tell you on Tuesday.
                       DR. POWERS:  It seems to me that it would
           be surprising if we didn't come back and say how come
           you guys haven't developed the standard review plan
           for power uprates.
                       DR. ELLIOTT:  Well, you may recall back
           again in December that they told you that they didn't
           plan to do it, and the committee took no action at
           that time.  They basically accepted that, and they
           claim that they have a template that they used based
           on the last two reviews, the Hatch and the Monticello,
           and that is what they are following.
                       VICE CHAIRMAN BONACA:  I am still left
           with some curiosity in my mind regarding how would 
           LRF be affected with a power uprate and containment
           that is not any more capable of being assumed
           strength, and assuming the PRAs.  I would just like to
           understand that.
                       And maybe the sensitivity on the PRA would
           give us some answer on what the sensitivities are.  I
           really don't know.
                       DR. KRESS:  I think the answer is that the
           containments fail at the discontinuity that Dana tells
           us about, and those probably don't change much by this
                       DR. POWERS:  We can probably get rid of
           the containments, and it is not doing any good for us,
           and --
                       DR. KRESS:  Yes, we might as well get rid
           of them, as they don't help.
                       CHAIRMAN APOSTOLAKIS:  Okay.  We are
           recessed until 1:15.
                       (Whereupon, at 12:15 p.m., the meeting was
           .                     A-F-T-E-R-N-O-O-N  S-E-S-S-I-O-N
                                                    (1:18 p.m.)
                       DR. POWERS:  I will bring this session
           into order, and we can just go right ahead with the
           presentation on the South Texas project.
                       DR. SIEBER:  Okay.  The lead speaker today
           will be John Nakoski, as the senior project manager
           for this project; and since I have read most of the
           things that you have written, you must have a sore arm
           by now.
                       I would also mention that we are getting
           down towards the end one way or another of this
           project, and I have received lots of mail from anyone.
                       DR. POWERS:  There are sore arms and a lot
           of us with sore fingers, right?
                       DR. SIEBER:  I would expect today to have
           us have concerns to ask questions to see if they can
           be resolved, and I intend to do the same.  And from
           those questions, you probably will get some of the
           gist of how we are thinking.
                       But right now, and until we are through
           hashing this over, we don't have a consensus yet, and
           hopefully we will arrive at one.  So with that kind of
           introduction, John, I would like you to begin.
                       MR. NAKOSKI:  Okay.  Thank you.  To my
           right is Jack  Strosnider, and he is the Director of
           the Division of Engineering; and to my left is Gary
           Holahan, and he is the Director of the Division of
           Systems Safety and Analysis.
                       I would like to go quickly just to refresh
           everyone's memory where we are and where we have been. 
           This is an effort that started in July of 1999.  We
           have met with South Texas a number of times, and those
           meetings are on here, but we talked about them before.
                       In January of 2000, we issued a request
           for additional information.  South Texas came in with
           a revised submittal in August of last year, and as you
           can see, we briefed ACRS on this issue a number of
                       In December of last year on the draft
           safety evaluation that we issued on November 15th, and
           in February of this year, we discussed categorization
           with the NCRS subcommittee.  In April of this year, we
           had a meeting with the full committee on treatment.
                       Recent activity is that the staff, the
           risk informed licensing panel, met with South Texas on
           the content of the FSAR.  In the middle of last month,
           we finally brought to closure all the open items
           identified in the draft safety evaluation.
                       And yesterday, the SE was forwarded to the
           EDO for his review in support of a July 20th
           commission meeting.  And we are here today meeting
           with the ACRS to cover our findings that are described
           in a preliminary safety evaluation that we made
           publicly available yesterday in a letter to South
                       Going forward, we expect to brief the
           Commission on July 20th, and following that, we expect
           to issue the notices of exemption and the final safety
           evaluation in August.
                       DR. SIEBER:  You will get a letter from us
           and it will probably come out in July, but we won't
           have enough time from this meeting to resolve
           everything and get it printed, and I don't think we
           will anyway.
                       MR. NAKOSKI:  And on our expectation, we 
           would expect that after the July meeting, after you 
           have had sufficient time to review the final safety
           evaluation, to provide us with your comments.
                       The conclusions that the staff reached in
           categorization is that we found or that we concluded
           that it is acceptable to categorize the risk
           significance of both the functions and the
           structure systems and components for use in reducing
           the scope of structure systems and components subject
           to special treatment.
                       It is also acceptable to define those
           structure systems and components for which exemptions
           from the special treatment requirements can be
                       DR. SIEBER:  Let me ask a fundamental
           question, and the answer is not in the FSAR, but when
           you use PRA, you calculate CDF and LRF, but if you
           look at the regulations, there are restrictions on
           plants, and there are components that are basic
           components according to 1.3 that are that way not
           because they impact CDF or LRF so much, but that there
           are other kinds of accidents or things that can
           release radiation either inside the plant or  outside
           to the public, like a spent fuel pool, and accidents,
           and so forth.
                       How do you assure yourself that you
           effectively blanket everything that is necessary by
           using just CDF and LRF as the metrics for
           categorization, or the deterministic process to the
           extent that it addresses that?
                       MR. HOLAHAN:  This is Gary Holahan.  In
           part, I think the answer is buried in your question,
           and that is that CDF and LRF don't measure --
                       DR. SIEBER:  Everything.
                       MR. HOLAHAN:  -- everything, and that is
           part of the reason that the categorization process,
           and the testing of what belongs in each of those
           categories can't be done just by the risk importance
                       In effect, there are many components that
           are not modeled in the PRAs.
                       DR. SIEBER:  That's right.
                       MR. HOLAHAN:  And that's because either
           the subject matter doesn't relate to core damage
           frequency, or even if it does, because they are
           screened out, or because their judgment is that they
           are not such important contributors, or they are
           subsumed in other super components if you will.
                       For all these reasons, we have pressed in
           this activity, as well as all our decision makings,
           back to regulatory guide 1.174, and that you need to
           have an integrated decision process that covers issues
           like defense in depth, and respects barriers, and
           safety margins, and good engineering processes.
                       So we don't have numerical metrics for all
           of those other things.  South Texas has a process that
           they use, and other people have used other processes. 
           But we recognize that the issues are more than core
           damage and large LOCA release.
                       And the measures are more than CDF and
           LRF.  So you have to look at the whole process, and we
           think that we have done that in this case.  So we hope
           to learn more about that.
                       DR. SIEBER:  So you are relying on the
           expert panel?
                       MR. HOLAHAN:  We are relying on the expert
           panel and that whole process involving the expert
           panel to capture the rest of the features.
                       DR. KRESS:  And that is what we mean by
           the categorization process and the whole thing.
                       MR. HOLAHAN:  By the categorization
           process, we mean the whole process and not just the
           importance measures.
                       VICE CHAIRMAN BONACA:  You know, on this
           issue, I was looking at the five questions that they
           have used as some question that would lead you to, for
           example, FSAR Part 100, and I thought that they
           related more to CDF and LRF conclusions, but you are
           telling me that they don't.
                       Or they may lead you, insofar as answering
           to those questions, to Part 100 releases, or for
           example, a limited amount of fuel damage?
                       MR. HOLAHAN:  I think that the questions
           are intended to do more than that.
                       VICE CHAIRMAN BONACA:  Okay.
                       MR. HOLAHAN:  I mean, we could ask South
           Texas for some practical examples, but for example, if
           I look at one of their questions, does the loss of
           function in and of itself directly cause an initiating
                       Now, that could cover events, whether they
           are dominant sequences in the PRA that might cover
           other initiating events as well, and that there is a
           value of protecting against.
                       VICE CHAIRMAN BONACA:  And if we could ask
           that question to South Texas?
                       MR. GRANTUM:  There are several questions
           that are used in the determination process, and this
           is Rick Grantum, South Texas.  The one that Mr.
           Holahan mentioned is one covering initiating events to
           cover a spectrum of initiating events.
                       We also have other questions that are
           associated with is the component mentioned or taken
           for in our emergency operating procedures.  So that
           carries another set of components, and a lot of those
           components are used, and the basis for those
           components being in the EOPs is Part 100 requirements
           and others of those aspects.
                       So we have a catchall in the EOPs that we
           take credit for, and we also ask questions relative to
           could it fail another risk significant component, and
           is it used to mitigate accidents or transients.
                       Those are the deterministic types of
           questions that the working groups and the expert
           panels deliberate on to encompass the concerns that
           have been mentioned.
                       DR. KRESS:  When you talk about the
           categorization process here, does that also include
           the sensitivities analysis?
                       MR. HOLAHAN:  Yes.
                       DR. KRESS:  You are considering that part
           of the process?
                       MR. HOLAHAN:  Yes.  In fact, if the
           sensitivity studies, which in fact I think are more as
           a Delta CDF, Delta LRF test, and if they showed that
           the cumulative effect of these proposed changes was
           too large, then in fact I think you would have to cut
           back on how extensive a list of low safety
           significance items you would put in that category.
                       DR. SIEBER:  That is the 1.174 test.
                       MR. HOLAHAN:  Yes, that's right actually. 
                       DR. SIEBER:  I guess in my opinion that
           you can categorize any reasonable engineering
           happening, provided that you have the sensitivity
           studies and apply the result to a comparison of 1.174.
                       MR. HOLAHAN:  Well, we talked about this
           subject before, and I think in terms of the things
           that can be measured by a PRA, the delta CDT test is
           more important than the importance measures.
                       DR. SIEBER:  That's what I think.
                       MR. HOLAHAN:  And the fundamental nature
           of it shows, because it is in reg guide 1.174, and
           importance measures are not.
                       Importance measures are discussed in some
           of the other issues, specific regulatory guides, but
           in all of those cases there really are subordinate to
           the overall goal of -- that the net effect of the
           change should be -- on risk should be small.
                       DR. SIEBER:  Right.
                       MR. HOLAHAN:  But neither of those
           processes captures the engineering safety margins or
           defense in depth issues.
                       DR. SIEBER:  That's right.
                       MR. HOLAHAN:  So you couldn't go directly
           to the Delta CDF and say that is the only issue.
                       DR. SIEBER:  If I performed the so-called
           thud test, and how much does it weigh, and how much
           space do you put in the FSAR for these various
           aspects, I see on page 16 that there is a paragraph
           that looks at the Delta CDF and Delta LRF as compared
           to the standard in Reg Guide 1.174.
                       MR. HOLAHAN:  Yes.
                       DR. SIEBER:  But as you described the
           screening process in the PRA, that is multi-pages, and
           indeed that is plant specific, because I think that
           the screening values, they don't seek to make a whole
           lot of difference on exactly what they are.
                       But you could choose another set of
           importance measures and as long as you could perform
           this test that is on the bottom of your page 16, you
           are okay.
                       So if you go and read it, it looks like
           this comparison was an after-thought, and all the
           categorization was done, and then they said, oh, gee,
           we have some metrics here that we can apply to the reg
           guide to show that we are okay, and that is sort of
           the impression that I get.
                       MR. HOLAHAN:  That is an impression or a
           perception that we would not like to have widely seen. 
           The real fundamental measure is that the change that
           you are doing has a small effect on risk.
                       DR. SIEBER:  That's right.
                       MR. HOLAHAN:  And I think the reason
           importance measures took a large place is that
           certainly in other applications we didn't know how to
           calculate Delta-CDF, and as a substitute, we said --
           for example, on graded QA and other issues, we said
           that one way of showing that the change in risk was
           small was by only allowing changes to components that
           we knew were very unimportant.
                       And having done that, we had a qualitative
           feeling that the Delta-CDF's risk effect was small. 
           In cases where we think we can calculate Delta-CDF,
           even though it is only through a sensitivity study, or
           give a range, I think that is important.
                       We have given some thought to the subject,
           and I would say one other thing.  I think you could
           meet the small effect on risk goal by almost
           arbitrarily picking the components and then doing this
                       But I don't think you could meet one of
           our other goals, and one of the goals of this whole
           process is that we should be focusing the staff and
           the licensee on those components that are most
           important to safety.
                       So I think it is advantageous to give the
           best shot we can at identifying important and less
           important components.  For example, you could approach
           this issue from a purely economic point of view, and
           go to the most expensive components and apply it, and
           keep subtracting until you get Delta-CDF is equal to
           whatever it is, and say that is where I am going to
                       I think that is not the overall safety
           approach that has been laid out.  What we have said is
           that that would not be focusing your attention on
           safety.  It is focusing your attention on the costs. 
                       And though we recognize that we would like
           to reduce unnecessary burden, we would like to do it
           in a way that produces a better safety focus.  So the
           categorization process in my mind is not arbitrary. 
           You ought to take your best shot at it, and then you
           ought to also test it with respect to its effect on
           the overall result.
                       DR. KRESS:  That leads me to believe sort
           of in an indirect fashion you are giving a blessing to
           the use of RAL and FSER vesely as a way to provide
           this focus on risk significant items.  Is that a
           correct interpretation of what you said?
                       MR. HOLAHAN:  In this case, yes.  I think
           what we have said in our general documents is that we
           have given these as examples, and not to say that this
           is the only way to do it.
                       But that you always ought to have more
           than one -- I think what reg guide 1.174 says is that
           you ought to have at least two risk matrix, and there
           ought to be two complimentary ones.  And it suggests
           that these are two of the four that are mentioned.
                       DR. KRESS:  The problem that I may have
           with that is that I am not sure that developing the
           RAL and FSER vesely for each individual component of
           an entirely group, of which there may be many of,
           correctly addresses the group importance, and in
           giving a blessing to the process under those
                       And that's all right for one component,
           and that's fine, or one or two components even.  but
           for a relatively large group of components, I am not
           sure it is wise to give that blessing at this moment
           to the use of RAL and FSER vesely of each individual
           component as a threshold to decide safety significance
           of the items.  Could you respond maybe to that?
                       MR. HOLAHAN:  I think there are a couple
           of unresolved issues with the importance measures.  So
           at the moment, in this application, we are satisfied
           with what was done.  In part, because we watched them
           do it, okay, and we saw how it was coming out.
                       And we know quite a lot about the PRA, and
           we know what the dominant risk sequences are, and what
           the total CDF and LRFs are for this plant.
           I don't think you can pick risk matrix -- FSER vesely,
           RAL, or any of these things -- and use them
                       I think it makes a difference whether the
           baseline risk is 10 to the minus 4 or 10 to the minus
           6.  I think that affects how you pick the components.
                       I think we all recognize that if you slice
           the pieces down to the sub, sub, sub, subcomponent,
           you could eventually show that everything isn't very
           important, every little piece isn't very important.
                       So what we found is that as it was done
           here is okay.  I think you have to be a little bit
           careful about extrapolating that to say any plant can
           pick up these risk matrix and these thresholds and use
           them in the future.
                       DR. KRESS:  Will that be made clear in the
                       MR. HOLAHAN:  Well, I think it is not so
           important in the FSAR.
                       DR. SIEBER:  It is in the FSAR.
                       MR. NAKOSKI:  This is John Nakoski.  I
           believe we do mention or state in the FSAR that these
           screening criteria, or FSER vesely and RAL, are pretty
           much SDP specific.
                       DR. SIEBER:  You say that, and you go a
           little bit further to say that it is not necessarily
           a template, and that is where I think we ought to be
           with this.
                       DR. KRESS:  And how is it that you know
           that the screening criteria is appropriate even for
           SDP?  Is it because of the sensitivity analysis
           verifies it?
                       MR. HOLAHAN:  The sensitivity analysis
           shows that the total of change can't be all that
                       DR. KRESS:  And if I do not have the
           sensitivity analysis?
                       MR. HOLAHAN:  It would be very hard to
           judge that.
                       DR. KRESS:  It would be hard to make a
           judgment on that?
                       MR. HOLAHAN:  Yes.  And I think also when
           you do a sensitivity analysis that you would find out
           that 99.99 percent of that change can change just a
           couple of components.
                       I think you would think that maybe you
           didn't do it right either.  In this case, I would have
           been surprised to find that.
                       DR. SIEBER:  Could you describe or give us
           a list of the sensitivity studies that were done?
                       MR. HOLAHAN:  I couldn't, but I think a
           member of our staff could.  Sam, Sam Lee.
                       MR. LEE:  Hi.  This is Sam Lee.  I am not
           sure if I understood the question.  The question was
           to give you a list of the sensitivity studies that was
           done for this particular --
                       DR. SIEBER:  What the perimeters were. 
           There was more than one study, right?
                       MR. LEE:  Yes.  First of all --
                       DR. SIEBER:  There was 21 studies or
           something like that.
                       MR. LEE:  The particular study that we
           focused our review on was the study where it took all
           the components and took the mean failure rate and
           multiplied by a factor of 10, and that gave us some
           sense that there were to be a change in reliability in
           these components.
                       And if we were to assume that it might
           have changed by a factor of 10, what impact would that
           have on the overall plant frequency.  That was the
           sensitivity study which we focused our view on, but I
           believe that maybe South Texas can help me with this.
                       Is that there were many more sensitivity
           studies done that were done to support that finding. 
           The other one that we also focused on was as you
           pointed out, that CDF and LRF were not the only matrix
           that we looked at.
                       We did ask the question in our REI as to
           how they accounted for the importance of those
           equipment that are there to protect the containment,
           and so one of the studies that the licensee performed
           for us was the failure containment probability.  That
           is another one that we looked at.
                       MR. GRANTUM:  This is Rick Grantum, and I
           can give you some other examples if you want to hear
           some more.
                       DR. SIEBER:  No, I would prefer in the
           interest of time, and we aren't even through the first
           sentence yet.
                       MR. HOLAHAN:  But there are only two
                       DR. SIEBER:  On the other hand, it is
           important for me to understand what the staff relied
           on to come to the conclusions in this FSAR, as opposed
           to how many thousands --
                       VICE CHAIRMAN BONACA:  I would like to ask
           just one more question before we move on, because I
           asked the question before with regard to the other
           measures of performance, and the answer was
           satisfactory to me.
                       But you also spoke about that you don't
           want to communicate, and when I read the FSAR, I
           really did not appreciate from it that that integrated
           process that really is the heart of 1.174 is truly
           addressed here through those measures.
                       I mean, maybe I didn't read it right, but
           it didn't come through, and so I am glad to hear that
           it was used.  But I think it could have been more
           explicitly addressed in the terms.
                       Because one is left with the impression
           that other subsumed goals, such as Part 100, are not
           being addressed, and that is really what I concluded.
                       DR. KRESS:  Before Sam Lee sits down, for
           the sensitivity studies, could you maybe tell me why
           it is that you feel comfortable with the factor of 10? 
           Do you have some database that says that?
                       MR. LEE:  When we first were reviewing
           their initial submittal, and we wanted to see --
           again, we are postulating that there could be changes
           in the reliability.  We are not sure of the
           reliability, but --
                       DR. KRESS:  You may not change it at all.
                       MR. LEE:  But what may be a good number,
           and the factor of 10 was actually submitted by the
           licensee.  But what gave us a sense of comfort for
           that was that if you look at most of the failure
           rates, and the distributions for the components in
           South Texas, you have a range of the 50th percentile
           to the 95th percentile.
                       And typically for those components, the
           error factor of three sort of lined up with the 95th
           percentile.  So in our view, if you had a factor of
           10, that well exceeded the 95th percentile.
                       DR. KRESS:  Somehow that doesn't give me
           much comfort, because that is a distribution of
           failure rates for things that have been given special
                       MR. LEE:  That's correct.
                       DR. KRESS:  And what I am really
           interested in is how would that change if the special
           treatment were not given to them, which means that you
           may shift the whole distribution one way or the other
           and by some amount.
                       And so I am more interested in whether
           there has been a comparison of things that have been
           given the special treatment with things that have not
           been given, and if you had any feeling as to that.
                       MR. LEE:  Well, that is really a good
           point, because a factor of three would be within the
           boundary of the 95th percentile.  That's why if you
           assume a factor of 10, it wouldn't actually exceed the
           distribution, and that gave us some sense that even if
           you were to shift the distribution to the right a
           little bit, that that might be bound by that.
                       But you are right.  It is hard for us to
           tell how much of that shift will be, and a factor of
           10 at this point gave us some sense that it would be
                       And again I would emphasize again that
           when you do the sensitivity analysis and you look at
           the results of the Delta changes, they are fairly
                       DR. KRESS:  They are really small with a
           factor of 10, yes.
                       MR. LEE:  Yes.  So maybe perhaps we can
           assume that if we were to extend the factor out even
           further, and we haven't -- and I don't think that
           South Texas has done that.
                       But even if we were to do that, my guess
           would be that it might still be within the window. 
           But I am not suggesting that we ought to do that.
                       DR. SIEBER:  One of the disappointing
           things to me is that not only does it seem a little
           arbitrary and we don't know the answer now, but we
           never will know it with the exemption on 50.65.
                       MR. STROSNIDER:  This is Jack Strosnider,
           and I would like to make a few comments on this
           because it starts getting directly to the treatment
           issue, and I guess just a few thoughts.
                       One is with regard to trying to quantify
           how this distribution shifts.  And I think we have to
           recognize that we can't quantify right now what the
           special treatment rules actually add in terms of CDF,
           or LRF, or any of these.
                       We don't have that quantified to begin
           with.  There was a lot of judgment and the intent was
           to maintain a high confidence and a high reliability
                       DR. KRESS:  Is there a database out there
           for failure rates of things like these that have been
           given the commercial treatment?
                       MR. STROSNIDER:  There is some, and South
           Texas did some work, and it is referred to in our SER.
                       MR. GRANTUM:  On page 53.
                       MR. STROSNIDER:  On page 53.  They looked
           at NPRDS, the nuclear plant reliability data system,
           for information, and it indicates here between the
           years of 1977 and 1996, and to try and answer the
           question of reliability of commercial versus safety
           related components.
                       And in fact I think the staff has tried
           this a few times in the past, and I think the
           conclusion was that there was no appreciable
           difference in the reliability.  In fact, it is not
           like you can actually tell if you were given a
           component and you tested it a while, it is kind of
           hard to tell if it is safety related or commercial.
                       MR. STROSNIDER:  I would just add that I
           think that is true based on the sort of data that was
           looked at, where you are looking at unavailability
           times and that sort of thing.
                       But I want to come back again to that I
           don't think you should really expect that there is a
           quantitative correlation here, or that it is easily
           quantified in terms of the change in treatment, and
           what the quantitative effect is.
                       And to recognize a comparison with
           commercial equipment and that the data does not
           include would this equipment function under seismic or
           harsh environments, or some of those things.
                       So you can get some insights certainly,
           but also some of the specific things that we are
           trying to look at are not directly addressed by that
                       But that tells you that you shouldn't
           expect necessarily a quantitative relationship, which
           is a valid question, and in the ideal world you would
           like to have that.  But then if you go another --
                       DR. KRESS:  Well, I just want a good
           feeling that in fact --
                       MR. STROSNIDER:  And to go another step,
           too, talking about the sensitivity analysis, and what
           does a factor of 10 tell you.  We discussed this at
           the last meeting on treatment, in terms of potential
           for common cause failures, and you could argue that
           changes in treatment could potentially influence that,
           and that was one of the subjects that we did discuss.
                       And I would just point out in the safety
           evaluation, which as John Nakoski indicated, is sent
           to the licensee, we stated our understanding of that
           sensitivity study and how it addresses the potential
           for common cause failures.
                       In fact, the licensees indicated that for
           certain groups of components, like MOVs, that it was
           not explicitly addressed in their sensitivity studies.
                       But we put down our understanding of it so
           that we could get confirmation from them when they
           look at this to see if it is accurate.  So those are
           all issues that come up in terms of the sensitivity
           studies, et cetera.
                       But the thing that I want to point out is
           that the finding that we were trying to look at, and
           I am getting a little bit ahead here, but what the PRA
           staff told the engineering staff is that you want to
           maintain functionality of this equipment.
                       And it might be with lower confidence, but
           you need to maintain functionality because I don't
           think that anybody concluded that these sensitivity
           studies indicated that if you had common cause
           failures of some significance that it might not impact
           the CDF and LRF values.
                       So when we start to talk about treatment,
           I would just point out and recognize that the intent
           is to maintain functionality throughout the life of
           the component under the design basis conditions.
                       DR. SIEBER:  Well, the point that I was
           trying to make though is that the maintenance rule is
           a way to gather information, and with the NEI Maint
           9.301, there is a lot of flexibility in how you group
                       You can group them by TRAM, by system, or
           by individual component, and it seemed to me that just
           keeping what goes on in the maintenance rule, since
           they already do it now, is not such a great burden.
                       And that you maybe get a better sense
           after a process like this was in process for a couple
           of years as to what those failure rates really were
           and how they would change, provided there was enough
           data to do it.  You know, you don't have 50 failures
           a day and so it takes a lot time to accumulate data.
                       MR. STROSNIDER:  But I do think that if
           you are going to try to address some of these issues
           through the maintenance rules, you would have to make
           sure that that program is really looking at some of
           these issues that are addressed by special treatment.
                       Again, harsh environment and seismic
           conditions, and those are tough things to get at, and
           that's why I said that in the end that you end up
           having to apply considerable judgment, in terms of
           what is the appropriate level of treatment.
                       DR. SIEBER:  Yes, but the problem is
           without the maintenance rule, you have no
           documentation, and so there is no chance of doing an
           analysis, even though you may not know what the answer
           is.  Well, that is my feeling on that subject.
                       DR. KRESS:  Could you give me a better
           idea of what you exactly mean by maintain
                       MR. STROSNIDER:  Well, let me go back and
           say let's start by thinking about what it is that we
           are looking at exempting.  If you look at the special
           treatment rules, at least to some extent, or I think
           to a large extent, the purpose of those was to make
           sure that that structure systems and components, when
           called upon to mitigate an accident, would perform
           their safety related functions.
                       And so this is mitigating an accident, and
           so you are into a situation where perhaps there is
           steam, radiation, humidity, whatever the environment
           is, and the component has to be able to function, and
           that is to deliver its safety related function under
           that environment.
                       Similarly, if you postulate the seismic
           event, that it will perform its safety related
           function under that seismic event.  So those are two
           easy examples of what the special treatment rules were
           intended to address.
                       Now, the question is if you go look at
           what is required by those rules and everything, can
           you for low safety significant components, can you
           relax some of the treatment, and the amount of rigor
           that is in those special treatment rules and to come
           up with a program that would still maintain
           functionality, but might not require as much in terms
           of whether it be documentation or testing, or whatever
           it is.
                       DR. POWERS:  I guess I am still struggling
           with the difference in your mind between functionality
           and availability is.
                       MR. STROSNIDER:  Well, there is in my
           mind, because if you look at availability, if a
           component fails to function under normal operating
           conditions, then you have probably got a pretty good
           indication that it is not going to perform under these
           more challenging conditions that I referred to.
                       But if a component does function under
           normal operating conditions, or if it is not called
           upon to function under normal operating conditions,
           but is called upon during the accident and the more
           severe conditions, you have to ask yourself are you
           getting information that says, yes, will it operate
           under those conditions.
                       Those are very difficult things to get and
           they always have been, and that should not be a
           surprise.  When you talk about collecting information
           on-line, how often do you really do a test under those
           sort of environments or seismic conditions?  You
                       That's why the special treatment rules try
           to address that in terms of the other elements that we
           will get to in the treatment program.  You know,
           procurement, and maintenance, and those sorts of
                       CHAIRMAN APOSTOLAKIS:  So functionality
           here means the ability to function as expected?  It
           has nothing to do with the probability that it will do
                       MR. HOLAHAN:  It has to do with
                       CHAIRMAN APOSTOLAKIS:  Capability.
                       DR. SIEBER:  I think a better comparison
           is to equate availability with operability, and
           operability according to the rules is a pretty high
                       You have to meet a number of rigid
           parameters for a component, and you can fail to do
           that, and it won't be operable or available, but it
           will still function, because maybe the service demand
           is not as severe as the envelope in which the
           component is supposed to be maintained to be operable. 
           I don't know if that makes sense or not.
                       MR. HOLAHAN:  I know of some utilities who
           use the terminology of big "O" operability and little
           "o" operability, because there is some legal
                       CHAIRMAN APOSTOLAKIS:  There is no Greek
           "O" there.  Remember Greek "O"?   Well, let's go back
           to the categorization, because we are mixing too many
                       And the thing that concerns me is that
           -- well, first of all, I agree with what Gary said
           earlier and what is in the FSAR, that the overall
           approach makes a convincing case, at least in my mind,
           that the risk 3 and risk 4 components belong there,
           and we can discuss their treatment and so on.  But
           what worries me is that if we approve this and list
           everything they have done, and put it in the FSAR and
           so on -- and I will use a word that was used a lot in
           our meetings with the Commission, that we will ossify
           the methodology, okay?
                       And that is not only -- I mean, that
           concern doesn't only have to do with the importance
           measures, but it is also the questions that the expert
           panel used with some issues here regarding the degree
           to which they overlap and so on, and evidently nobody
           really thought about them.
                       It was a purely -- and that reminds me a
           little bit of the old days when we were dealing with
           expert judgment.  If an academic was doing the
           exercise, they would tend to invite academics, and so
           they would talk about pumps in the abstract.
                       If engineers were to do it, they would
           invite pump experts, and they would have no idea as to
           the normal part of dealing with expert opinion.  It
           dawned on us with 1.150 and later studies, that
           actually you need both kinds of expertise.
                       And you need the normative expert and the
           substantive expert, and here I think the expertise
           that was missing was the normative kind.  You know,
           the structuring, and maybe it was missing in the
           actual work that you did.
                       But if I look at the paper that I have in
           front of me, and questioning the overlapping, and at
           the same time if I read the whole thing, I say, my
           goodness, the overall conclusion makes sense.  It does
           make sense.
                       I may pick one page and say why did you do
           it this way, and you could do it better, but does that
           really change the conclusion?  But what worries me is
           that what if you have 20 licensees tomorrow who come
           and repeat everything that South Texas did and a
           factor of 10?
                       Why not a factor of five?  It seems to me
           that to shift the mean value by a factor of five is a
           heroic effort.  You are shifting the mean.
                       DR. KRESS:  That would be a hard thing to
                       CHAIRMAN APOSTOLAKIS:  And you are taking
           the whole distribution and putting it up there, you
           know.  And judging from the weak evidence we have,
           Gary, you said that they couldn't tell the difference
           between the failure rates.
                       So all this stuff, it would be nice to
           have some incentive to think about it without
           necessarily -- you know how it is.  If these guys
           approve something, that's it.
                       MR. HOLAHAN:  If they can get away with a
           factor of five that would be an incentive.
                       DR. SIEBER:  One wonders whether that
           would make any difference.
                       CHAIRMAN APOSTOLAKIS:  But you know how it
           is.  The moment it is approved though, everybody else
           says we are going to get it, too, and that's it.
                       MR. HOLAHAN:  I am not so concerned about
           the ossification problem.  It is not as though this is
           the lead plant in an exercise where we expect other
           plants to follow this model.
                       Remember that the overall context of this
           is we are working risk informed regulation, Option 2,
           rule making.  And this is sort of a proof of principle
           that shows that we are capable of defining a program
           and a licensee is capable of implementing such a
                       I think the issue of how to do this more
           generically so that it applies to everyone still faces
           us, and it is an integral part of Option 2 and the
           rule making activity.
                       So I don't see this as the model that will
           last and be used by many people.  I see that as being
           framed by how we deal with these issues in Option 2
           and in a rule making context.
                       CHAIRMAN APOSTOLAKIS:  And when is that
           going to take place by the way?
                       MR. HOLAHAN:  Well, we have already
                       DR. SIEBER:  Is there any more questions
           on this first sentence?
                       DR. LEITCH:  I am in the first paragraph,
           and I guess that's all one sentence.  So, yes.  I am
           concerned about the reliability of the instruments,
           particularly control room instruments that the
           operator uses to make significant decisions.
                       And there is a subset of those instruments
           described in what I think is Reg Guide 1.97 if my
           memory serves me correctly.
                       CHAIRMAN APOSTOLAKIS:  That's it.
                       DR. LEITCH:  And the operators are trained
           in accident situations to specifically rely on those
           instruments.  And I guess my question is whether is it
           fair to assume -- and I think it is, but I just would
           like to hear confirmation, but is it fair to assume
           that none of those instruments would have been
           categorized as Risk 3?
                       MR. HOLAHAN:  Well, let me answer the
           question a little differently.  The staff is approving
           a process, and so we can't give you a list of how
           these components fall out in the process.
                       As a matter of fact, probably most of that
           categorization hasn't been done.  We approve a process
           and over a period of time a licensee will implement
           this system by system.  So many of those components
           may not have been categorized yet.
                       DR. LEITCH:  But what you understand of
           the process, would you expect that the process --
                       MR. HOLAHAN:  From what I understand of
           the process, I would think that particularly the part
           of the process that addresses the expert panel and the
           look at the emergency operating procedures would go
           directly to those instruments that are referred to in
           the emergency operating procedures.
           And that would push them into the high category.
                       DR. SIEBER:  Well, this is question two in
           the deterministic section on page 18, which tells me
           that if it is in the EOP or an ERG, it is category one
           or two.
                       CHAIRMAN APOSTOLAKIS:  Now, one other
           thing about ossification.  The extensive use of
           conservative assumptions in a risk-informed framework,
           I think we ought to be very careful before we start
           doing that.
                       And a factor of 10 is one, and I think it
           is conservative from everything that I know about it.
                       MR. STROSNIDER:  I guess I would just
           suggest that we probably need to think about that.  If
           I could give some examples.  There was a discussion on
           just one of the open items that we had, which was how
           you treat metering test  equipment and whether you
           found that that metering test equipment was out of
           calibration if you needed to go back to some of these
           slow safety significant equipment and recalibrate it.
                       The original proposal was not to do that,
           and the only reason that I bring that up is because
           there is the potential if you look at something like
           that for treatment.
                       If you had something that was really way
           out of calibration, and to go off and mis-calibrate a
           set of equipment, such that it wouldn't function
           -- and the shift there is much greater than -- could
           be much greater than a factor of 10.  We dealt with
           that open item, and --
                       CHAIRMAN APOSTOLAKIS:  A shift of what?
                       MR. STROSNIDER:  In the probability of
           functioning.  If you take equipment -- and let's say
           it starts at 10 to the minus 3rd probability of
           functioning, and you go out and you mis-calibrate it,
           it may go to a point where it is not going to
                       And if you do that across a number of
           different components, you could have an issue.  Now,
           like I said, that is an open item that we dealt with,
           but when you start talking about treatment, there is
           the potential to have impact on functionality.
                       And if you are starting at 10 to the minus
           3rd, and you say I am going to go from one in a
           thousand chance that it doesn't work to one in a
           hundred --
                       CHAIRMAN APOSTOLAKIS:  Yes, but mis-
           calibration is not part of the failure rate as far as
           I know.  Mis-calibration is a human error that is
           found separately, and they didn't increase that by a
           factor of 10.
                       If a failure rate is due to random causes,
           and it is very hard to say that going up by a factor
           of 10, the mean value.
                       MR. STROSNIDER:  I would suggest that
           there is random causes, but one of the other issues
           that you really want to think about when you are
           talking about changing treatment is the potential for
           common cause failures; common cause maintenance,
           common cause calibration and the sort of things that
           I was mentioning, which could affect more than a
           factor of 10.
                       CHAIRMAN APOSTOLAKIS:  Were these
                       MR. STROSNIDER:  Well, again, I would like
           to put that into the context of that is one of the
           reasons when we get to the treatment discussion, where
           we will say that the objective of the treatment
           program is to make sure that these structure system
           components will function, and that functionality is
           being maintained.
                       And that is one of the reasons it is
           important to put that as a goal of the treatment
           program because of those kinds of considerations.
                       MR. HOLAHAN:  I would like to go back and
           say something about conservatism, because there is
           some forms of conservatism that I think are
           detrimental to a risk informed process and others that
           are not necessarily.
                       If you make some conservative assumptions
           in the PRA in some areas, you will distort the
           perception of what is important and what is not, and
           those are I think destructive.  That sort of
           conservatism will in fact change the importance
           measures, and it will change what goes into the
                       The kind of conservatism associated with
           picking a factor of 10, as opposed to something else,
           I don't think distorts the results.  It may put a
           little more margin in some way in your decision.
                       It may restrict you in how many components
           go in this category versus that one, but I don't think
           it is as serious a concern as sort of distorting your
           views so that you are not really focusing on the most
           important things.
                       You are simply focusing on the things that
           you assumed were problems, and drove those to be the
                       CHAIRMAN APOSTOLAKIS:  On the other hand,
           if a factor of 10 is used 2, 3, or 4 times, then it
           becomes part of the tradition, and then the first guy
           who cannot show that a CDF has been small with a
           factor of 10 is stuck.
                       Now what do you do?  If he dares go down
           to a factor of five, all hell is going to break loose
           again.  So that is the danger of that, and also the
           treatment of common mode failures, and taking the
           whole importance of the therm, and putting it under
           one component, that is also a conservative thing to
                       And again we don't want to bless those and
           have them there forever.  For a particular regulatory
           decision, I think conservatism is fine, but again this
           works now and it doesn't work tomorrow.
                       And the whole idea of risk informing the
           regulations is to be as realistic as possible.
                       DR. SIEBER:  But it seems to me that that
           kind of literary discussion would go on with the
           writing of the rule and its companion reg guide, which
           would be the suggested implementation; as opposed to
           trying to somehow or other weave it into this
           particular set of requests for exemption, provided
           that those documents appear within my lifetime.
                       CHAIRMAN APOSTOLAKIS:  So let me
           understand you.  You are asking STP to put all this
           stuff in the FSAR, right?
                       MR. HOLAHAN:  All this stuff?
                       CHAIRMAN APOSTOLAKIS:  The thresholds that
           they use for all --
                       MR. HOLAHAN:  Yes.  Yes, we are.
                       CHAIRMAN APOSTOLAKIS:  So I guess you have
           categorized all the components, right?  Are there any
                       MR. CHINSEL:  Yes.  We have done about
           45,000 systems.
                       CHAIRMAN APOSTOLAKIS:  How many all
                       MR. CHINSEL:  There is a few over a
           hundred-thousand per plant.
                       CHAIRMAN APOSTOLAKIS:  But these remaining
           55,000 are not in the PRA and so the importance
           measures are irrelevant, right?  It would be part
           basically of the expert --
                       MR. CHINSEL:  Some of the components are
           still in the PRA that we have not yet categorized.
                       MR. HOLAHAN:  I think we are going system
           by system.
                       MR. CHINSEL:  That's correct, going system
           by system.
                       CHAIRMAN APOSTOLAKIS:  So you are blessing
           this particular process with the 50,000?
                       MR. CHINSEL:  Yes.
                       DR. SIEBER:  And that's probably why you
           are putting the metrics in there specifically as
           numerical value.
                       MR. HOLAHAN:  I think we are also putting
           it in there --
                       DR. SIEBER:  It describes the process that
           they are using.
                       MR. HOLAHAN:  Yes.  I think we are also
           somewhat constrained by the fact that this is an
           exemption, and that we have not been through a rule
           making process, and in fact we are making a finding
           that this is an appropriate substitute for the normal
           regulations in these areas.
                       I think we were probably somewhat more
           constrained in being less flexible in how a licensee
           can change this process than we may be at the time
           when the rule making is done.
                       If you think of it analogously, we have 
           50.59, and which allows licensees in other areas in
           effect to make changes and through a certain set of
           tests, they are basically saying that they judge that
           they are still in conformance with the regulations
           under this change situation.
                       In this case, if we were to allow
           additional flexibility, in effect what we are saying
           is that the licensee doesn't meet the regulations, but
           we have defined some other process.
                       And to allow them to change that process,
           and for them to decide that they still don't meet the
           regulation, but they have some other standard which
           they decided as good enough to grant them an
           exemption, it is not something that we would normally
                       I mean, we really don't have a process for
           doing that.  So there are some constraints associated
           with the fact that this is an exemption, as opposed to
           a license amendment, or even a rule change.
                       DR. SIEBER:  Okay.  John, maybe we can
           move on.
                       MR. NAKOSKI:  Okay.  This is John Nakoski
           again.  If we can get to bullet two on slide three. 
           This deals with the conclusions that we drew on
           treatment, and what we concluded was that the
           alternative treatment program proposed by South Texas
           includes the necessary elements, and that if South
           Texas effectively implements them, can result in the
           safety-related low risk components remaining capable
           of performing their safety functions under design
           basis conditions.
                       CHAIRMAN APOSTOLAKIS:  Why do you need to
           say if effectively implemented?  I mean, was there any
           intended proposed alternative treatment program and
           was that effectively implemented?
                       MR. NAKOSKI:  It is not -- it doesn't
           indicate that, but we believe that it would be
           ineffectively implemented.  It is just that it is an
           indication that the burden for effective
           implementation remains with South Texas.
                       MR. NAKOSKI:  This is Jack Strosnider, and
           just to point out that is where that burden always is. 
           The licensee has that responsibility, and it
           emphasizes that, but it also was intended to point out
           the fact that the staff did not do a detailed review
           of how this treatment would actually be implemented.
                       Normally our more traditional approach is
           that we get down into looking at procedures, and we
           get down into a lot of very specific issues.  We tried
           to avoid that in this review.
                       The reason for that is that recognizing
           that this is, given the robust categorization process,
           that this is low safety significant components, so
           that we didn't need to go into that level of detail.
                       But we wanted to make sure that the people
           understood that we didn't, all right?  And what we
           looked at was the high level programmatic elements,
           the expected outcomes, and I will acknowledge that in
           some cases that we expanded on what was meant by some
           of that, in terms of what we thought needed to be in
           the FSAR.
                       But we tried to focus, and you have heard
           some of the prior discussions on the what's; that is,
           what is expected, versus how it is actually going to
                       And it would have been a different review
           if we really had gone down into how are you
           specifically going to treat this piece of equipment or
           that piece of equipment.
                       DR. SIEBER:  I think one of the
           interesting things is that the way that this is laid
           out is pretty good, because it actually quotes what is
           going to go into the FSAR, and when I examined the
           proposed treatment requirements, I noticed in a number
           of places where decisions are being made, or where
           things are happening, and engineering decisions, like
           equivalency, and that kind of stuff.
                       And in the training program, my program is
           just as good as the vendor's recommended program.  The
           last sentence in every one of those is that no
           documentation is required.  I don't see how you can
           manage your engineering department or your training
           department without documentation, which is the basis
           upon which you make decisions.
                       So I am wondering if you are putting the
           time in to make the decision, or to do the analysis,
           why can't you spend a little extra time and write it
                       MR. NAKOSKI:  This is John Nakoski.   It
           is not that we would not expect South Texas to have
           some sort of documentation.  It is just that we would
           not require that to be documented.
                       For their business practices, you are
           right.  They would need to have some sort of records.
                       DR. SIEBER:  I don't understand how you 
           could do a good job of organizing engineering without
           writing down the basis of the decisions that you make. 
                       And I guess the other thing that strikes
           me then is what if issues come up where enforcement is
           necessary by the NRC, you wouldn't have a basis upon
           which an enforcement action could occur, because they
           wouldn't be required to keep the record.
                       MR. STROSNIDER:  And there was actually a
           lot of discussion internally with regard to
           documentation.  Of course, again trying to look at
           this from a risk-informed perspective, and looking at
           various areas where you can reduce unnecessary
           regulatory burden, the discussions were what sort of
           documentation is really essential and needs to be
           maintained in accordance with existing special
           treatment, and what can we let go of in a sense.
                       We talked about equipment qualification as
           an example, and that is one area where if you look at
           the special treatment rules, there are some
           significant requirements for documentation, and
           quality assurance, et cetera.
                       DR. SIEBER:  Yes, I didn't discuss those.
                       MR. STROSNIDER:  And if you accept the low
           safety significance of some of these components, then
           you might not need that same amount of rigor.  Yes,
           the expectation as I said, and if you look at each one
           of the elements in this program, there is an
           expectation stated at the beginning of it in terms of
           maintaining functionality.
                       Whatever the licensee needs to do in order
           to keep track of that, they would have to do, but that
           is their determination at this point.  EQ might be an
           example where you say if you want to understand the
           qualified life, and at what point do you need to deal
           with that.
                       And the expectation is that they would
           maintain the functionality of this equipment, and if
           there is something that needs to be checked at some
           period, then they would have to do that.
                       But we are not prescribing, like what is
           prescribed in the special treatment rules, what is
           necessary, so that they could get by with just what is
           necessary for them to meet these outcomes.
                       So it is a different approach and you have
           to look at it and recognizing its low safety
           significance components.
                       MR. HOLAHAN:  I think you also have to
           look at this issue in the context of the new reactor
           oversight process, and which the expectation would be
           that because these are low safety significant
           components, it is very unlikely that they will ever be
           above the licensee response zone.
                       And so you would expect the licensee to
           find and fix these issues, but you wouldn't expect
           them to require any elevated attention by the NRC.  I
           am not saying it is impossible, but normally you
           wouldn't expect that.
                       DR. WALLIS:  You took the trouble to put
           in this phrase of "if effectively implemented by the
           licensee."  That kind of implies that someone is going
           to check up on it.  So what is the mechanism for
           checking up on this effectiveness of implementation?
                       MR. STROSNIDER:  I think you are looking
           at the reactor oversight process.  I don't think it
           would be the intent to focus our inspections on low
           safety significant components unless something drives
           you into that from the perspective of the oversight
           process, in which case then it would be dealt with.
                       DR. WALLIS:  If you are going to take the
           trouble to mention it though implies that you are
           saying that someone has to check up on it in some way
           from time to time, and I am just wondering where it
           falls in the inspection process.
                       MR. HOLAHAN:  In the reactor oversight
           process, because it is a low safety significance, they
           are not likely to be focused on.  So the normal place
           to see them is in the inspection of the corrective
           active program, which is one of the central elements
           of the inspection program.
                       DR. SIEBER:  And no exemption was
           requested from any element of that.
                       MR. NAKOSKI:  That's correct.  Corrective
           action requirements of Criterion 15 and 16 of 10 CFR
           50, Appendix B, continue to apply.
                       DR. SIEBER:  That's right.
                       MR. HOLAHAN:  And the reason that the
           reactor oversight process includes corrective action
           is because obviously we have put a lot of these lower
           issues into the licensee response area, and so we need
           to have some mechanism -- and not just for these
           specific components, but for the whole program -- to
           see that they are responding effectively to all of the
           issues that are below the green light threshold
                       DR. SIEBER:  So the documentation
           obviously for Risk 4, and also now for Risk 3, is of
           no regulatory concern?
                       MR. HOLAHAN:  That's correct.  Quality
           records would not be required.
                       DR. SIEBER:  On the other hand the
           licensee has to understand that even in a coal plant
           that you keep records when you maintain things, and
           when you calibrate them, and what engineering
           decisions that you make, and operating difficulties,
           and that type of thing.  That is standard business
                       MR. HOLAHAN:  I think we have talked about
           documentation, but this exemption does not remove
           documentation completely.  There are certain areas --
                       DR. SIEBER:  I know that, right.
                       MR. HOLAHAN:  -- of design and corrective
           action and documentation will still be there.
                       MR. NAKOSKI:  Okay.  We can move off the
           third slide, and go to findings that the staff made. 
           These are really findings that we have to make in
           order to grant the exemptions.
                       The first one is that we found that
           relaxing the special treatment requirements on these
           low risk components poses no undue risk to public
           health and safety.
                       We also found that the categorization
           process is a material circumstance that wasn't
           considered when the special treatment requirements
           were adopted.
                       And we may have considered risk insights
           when some of these regulations were adopted, but we
           have never I believe considered an integrated decision
           making process like proposed by South Texas.
                       We have also concluded that it is in the
           public interest to grant the exemption.  That is
           primarily that we have improved efficiencies and
           effectiveness in the application of our oversight.  We
           target our attention better on those risk significant
           components and functions at South Texas, and South
           Texas can do the same.
                       Now, we also found that the proposed SFAR
           section is a sufficient basis for granting the
                       South Texas requested -- I believe it was
           18 -- exemptions from 18 regulations, and to one
           extent or another, exemptions for low safety
           significant, non-risk significant components that fall
           within the scope of these regulations.
                       And the ones that are listed here on the
           slide are being granted.  If I can talk just a little
           bit about some of the rules and where there are some
                       On 10 CFR 50.49(b), which would exempt
           essentially all of these LSS and NRS components from
           the scope of the environmental qualification rule,
           there are some design aspects that continue to apply,
           and it is covered in the safety evaluation.
                       The exemption to 10 CFR 50.59, really it
           only applies to changes to treatment that result from
           the granting of these exemptions.  For any other
           change to the FSAR or any other licensing basis
           document, the requirements of 50.59 continue to apply. 
           The Appendix B --
                       DR. SIEBER:  The change to treatment was
           to cease maintaining the item and turn it into a
           breakdown of maintenance, where would that fall under
                       MR. NAKOSKI:  If it was covered by the
           scope of an exemption that we granted, they would not
           have to seek prior staff approval for that.  If it
           wasn't covered by an exemption that we granted, they
           would have to come in if when they were doing their
           50.59 evaluation that it required prior staff review
           and approval.  Did that answer your question?
                       DR. SIEBER:  Even if it was Risk 3?
                       MR. NAKOSKI:  If it was outside the scope
           of an exemption we granted, yes, they would have to
           come in for -- if it was for the threshold of 50.59. 
                       In other words, if they have a commitment
           in their licensing basis that isn't part of this --
                       DR. SIEBER:  Well, you have a commitment
           to the PM program, but you exempt portions of that,
           basically saying that just a PM program to match
           commercial standards, whatever they are.
                       Then there is a phrase that is in there a
           couple of times that the licensee is not obligated to
           list all the commercial standards, and what the State
           of Texas says they ought to do, which could be the
           State of Pennsylvania, or Maryland, or whatever.  They
           all do the same stuff.
                       And so I could picture taking that to its
           extreme limit, and somebody deciding that I am going
           to save money and I am not going to change the oil
           except every 10 years.
                       MR. HOLAHAN:  I don't think that you could
           make that decision and be consistent with a
           description of the program in the FSAR.
                       MR. NAKOSKI:  That's correct.
                       MR. HOLAHAN:  And what this is basically
           saying is that you can't change -- you can change the
           programs so long as it still conforms to what is in
           the FSAR, and there is probably a lot of flexibility
           for doing that.
                       MR. NAKOSKI:  I think there is actually
           confusion, and this is John Nakoski again.  The 50.59
           process is basically -- the exemption that we are
           granting them for 50.59 basically applies to changes
           that they will need to make to their FSAR as a result
           of the exemptions that we grant.
                       There is going to be an addition.  They
           are going to add a section to the FSAR that lays out
           their categorization and alternative treatment
                       In there also will be a change control
           process for how they control changes to that Section
           13.7 of their FSAR.  It kind of lays over any
           requirement that 50.59 would impose on that section. 
           So if the wanted to change the treatment that is
           described in Section 13.7 of their FSAR --
                       DR. SIEBER:  They have to ask you first.
                       MR. NAKOSKI:  -- and if it reduces the
           effectiveness, it has to come back in, because it will
           undermine or has the potential to undermine the basis
           for our exemption.
                       DR. SIEBER:  And 50.65.
                       MR. NAKOSKI:  And 50.65, the maintenance
           rule, there is recently 50.65(a)(4), which came into
           effect, and that continues to apply to all components
           within the scope of the maintenance rule.
                       DR. SIEBER:  Maybe to help us, you could
           tell us what (a)(4) does.
                       MR. HOLAHAN:  And I am drawing a blank. 
           Well, (a)(4) requires licensees to assess and manage
           the risk associated with taking components out of
                       DR. SIEBER:  Okay.  And since these are
           low risk things, it is not hard to manage.
                       MR. HOLAHAN:  Right.
                       DR. SIEBER:  On the other hand, you lose
           again some of the tracking and records, like taking
           20,000 components out of the maintenance rule, and
           that gets back to my --
                       MR. NAKOSKI:  I will say that part of the
           South Texas monitoring program is if a low risk
           component impacted an HSS or MSS function, they would
           capture that failure.  So that data would be captured.
                       But if its failure impacted or affected a
           low risk or non-risk function, it wouldn't be
           captured.  So again it is targeting the attention on
           the high risk, medium risk functions that we want to
           focus on.
                       DR. SIEBER:  And if I go through the
           deterministic screening questions, it would seem to me
           that there would not be a low risk component that
           would affect or disable a high risk frame, right,
           because it wouldn't get screened out.  It would not
           get screened into a risk series.
                       MR. NAKOSKI:  That is our expectation;
           that if it does occur that it would be infrequent.
                       DR. SIEBER:  And it would almost seem like
           it was impossible.  On the other hand, you are
           expecting functionality of even RSC-3 components, but
           you won't have a record.
                       MR. NAKOSKI:  I'm sorry, but I didn't
           catch that.
                       DR. SIEBER:  There won't be a record as to
           whether it was functional or not.
                       MR. HOLAHAN:  But from a safety point of
           view, it isn't that important.
                       MR. NAKOSKI:  I would modify that to say
           that there wouldn't necessarily be a quality record
           under an Appendix B program.
                       DR. SIEBER:  You aren't requiring any
                       MR. NAKOSKI:  That's correct.
                       MR. HOLAHAN:  Except corrective action
           program and design basis.
                       MR. NAKOSKI:  And design control.  Under
           10 CFR 50, Appendix B, quality assurance criteria, as
           we discussed previously, Criterion 3, design control,
           and Criterion 15, with non-conforming materials,
           components, and parts; and 16, correction actions,
           continue to be in effect.
                       The exemption to Appendix J is for type
           leak rate testing only; and the exemption to Part 100,
           the design requirements continue to apply as described
           in Part 100.
                       And the exemption is to the specific
           engineering analysis and testing requirements in Part
                       There were some exemptions that we
           determined that we would not grant, and primarily the
           general design criteria -- really because what the
           licensee proposed met the regulations for GDC-1, and
           this relates to the other two at the bottom of the
           slide, 50.35(b)(6))ii), and 50.54(a)(3).
                       Early in the review process, we recognized
           and South Texas recognized that really we needed to
           have a quality assurance program updated to reflect
           the changes in treatment, and if for nothing else, as
           a record keeping tool.
                       And as a result, they submitted and we
           found acceptable as discussed in the safety evaluation
           their proposed revision to the operating quality
           assurance plan, and so that met the requirements of
                       GDC-2, 4, and 18, they deal with design
           requirements, and the design isn't being changed under
           this exemption or under Option 2.  So really they
           don't fall within the scope, and there is no special
           treatments for which exemptions should be granted.
                       Now, as I said, the last two, we
           determined that an update to the QA program should be
           done and South Texas agreed.  So we aren't granting
           those exemptions either.
                       And with that, that is the prepared
           material that I had for the meeting today, and we
           would be happy to answer any additional questions.
                       DR. SIEBER:  I suspect there are no
           shortage of questions.  If anyone would like to ask
           questions that are disturbing them at this time, this
           would be a great chance as we are ahead of schedule.
                       DR. POWERS:  I guess my question is have
           we resolved the question.
                       DR. SIEBER:  Well, it all depends on what
           you would call resolution, and that it may not
           necessarily be pertinent.  On the other hand, I think
           that the question that I have asked will cover the
           areas of concern, and we are trying to decide now how
           important my feelings really are to the success of
           this project, and that will take a little bit more
           thinking on my part.
                       But I am sure that others have asked a lot
           of questions of me that seem to be pretty burning.
                       DR. POWERS:  Let's come back to the
           question on the cut-offs for FSER vesely -- well, the
           issue is that they picked some values and used them in
           this application.  But it seems to me that those
           weren't particular outlandish values that they picked. 
                       In fact, they seem kind of common, but
           there seems to be some interest in claiming that those
           aren't not be a template for others to use, and so my
           question is why not?
                       DR. SIEBER:  Well, that was my comment of
           10 days ago, and it was really responding to Dr.
           Apostolakis' remark about ossifying some methodology
           industry wide, and that was really the purpose why I
           said it shouldn't be bound to use those screening
           criteria for bound to use questions that they asked in
           the rating system that went alongside that.
                       And the general methodology was okay, and
           I basically say that because my personal opinion
           really is it doesn't make a lot of difference how you
           do the categorization provided that you have no heavy
           hitters in there, and that you meet the criteria of
           Reg Guide 1.174.  And so it was an attempt to satisfy,
           and it could go either way.
                       DR. KRESS:  My problem with that, Dana, is
           two-fold.  One of them is that those importance
           measures have the absolute value of the CDF and the
           LRF, if you are  using LRF also, in the denominator.
                       Therefore, almost automatically it makes
           them plant specific.  Now, that may look like a simple
           fix.  You just take the numbers and multiply them by
           the -- or ratio them by the CDF, and you have got
           another set of numbers.
                       MR. HOLAHAN:  Or perhaps we should put the
           safety code quantitative objectives in the
                       DR. KRESS:  That would be another way to
           fix it.
                       DR. SIEBER:  But that may change
                       DR. KRESS:  So that was one of my
           problems.  The other problem that I had though -- and
           I think it is a deeper problem -- is that I am not
           quite sure that I agree with Jack that the
           categorization process doesn't matter.
                       You have got the expert opinion, and you
           could use a ouija board, and you could throw darts,
           and as long as you validate it with your sensitivity
           analysis, but I am not quite comfortable with that
           because I have a feeling that there is a way to decide
           what thresholds to use for RAL and FSER vesely that
           would give you a given change or a given percentage
           change in CDF and LRF.
                       I am not certain of that because I have a
           real problem -- what we found with each of these RALs
           is the individual RAL for each component, and I don't
           know how to combine those for a bunch of components.
                       You just don't multiply by a number of
           components, or you don't add them up, but what I am
           afraid of that we will quit here.  When I think there
           may be somewhere in these definitions of RAL and FSER
           vesely a way to actually technically defend their use
           in bounding the group RAL, and the group LRF, and I
           just did not want them to quit here and say now it
           doesn't matter.
                       But if there is a way technically to come
           up with that group RAL, that would be a value for a
           lot of the risk-informed things that we are going to
           do later on, and we may want to use those things.
                       And it is extension of the technology of
           using RALs and FSER vesely, and other important
           measures, to the other risk informed processes that
           worries me.
                       And I just did not want them to quit
           because while we have got this sensitivity study or an
           uncertainty analysis, whichever you want to use, to
           validate it, because it doesn't matter how you got
                       I think it does matter because I think it
           is going to be used in other processes and it could be
           misused, and I think it is an opportunity to further
           develop the concept so that it is technically
           defensible.  That was my worry.
                       DR. SIEBER:  And I guess if I were South
           Texas, I would wonder why I am getting stuck with
           doing the extra part.
                       DR. KRESS:  And that is the other part. 
           I didn't to penalize South Texas, because I do agree
           that they have jumped through enough hoops and that I
           do believe that the sensitivity study does confirm
           that their process fits into the 1.174.
                       I just didn't want to -- I think this is
           an additional research project that needs to be done,
           and I didn't want to bless the process as it is for a
           group RAL or a group FSER vesely, and I wanted to be
           sure in the whole letter or whatever we do that we
           don't bless that, because I don't want to stop with
                       CHAIRMAN APOSTOLAKIS:  Isn't that a little
           related, Tom, to the issue identified with respect to
           the risk-based performance indicators?
                       DR. KRESS:  It is related definitely, and
           I am afraid that there may be other places in the
           risk-informed process where it is related.  I didn't
           want to leave the impression that just because it is
           okay to give South Texas their exemption because they
           did this that we have a process that is technically
           defendable, in terms of actually determining -- well,
           the process is here because it was confirmed by the
           sensitivity analysis.  That is the technical defense
           of it.  You may not have a sensitivity analysis for
           all these other things.
                       DR. SHACK:  You are always going to have
           to compute, or bound, or estimate Delta-CDF for it to
                       DR. KRESS:  Well, this is what I am
                       DR. SHACK:  The sensitivity study in this
           case is a substitute for computing Delta-CDF.
                       DR. KRESS:  What I am saying though is
           there may be a way to use RAL, and FSER vesely to
           determine that bound without going to the sensitivity
           analysis if you did it right.
                       That is what I am saying ought to be
           developed.  You wouldn't have to do the sensitivity
           because we were able to do the sensitivity here
           because we got a good warm feeling that Factor 10
           really does bound the effects.
                       We may not have a warm feeling about some
           other thing, and we may not be able to do this
           calculation.  It would be useful to have a RAL and a
           FSER vesely that you actually knew did bound a group
           effect, and that is what I am saying.
                       CHAIRMAN APOSTOLAKIS:  We can put it in a
           different way.  I think it is defensible the way it
           is, but we wouldn't want it to stay that way.  I mean,
           we want it to stay defensible.  We would not want the
           methodology to be frozen for all these reasons.
                       DR. SHACK:  Well, I would agree with that. 
           I would look at it in a different way.  I mean, we --
                       CHAIRMAN APOSTOLAKIS:  There is always a
           third way.
                       DR. SHACK:  When you select these
           components, you are satisfying other things other than
           the Delta-CDF and the Delta-LRF, and you get other
                       You know, as we argued, the FSER vesely
           looks at the risk significant components, and the RAL
           looks at the stuff with the low failure rates if it is
           really safety significant here.
                       You are gathering things together, and so
           those populations that you do gather and test, and see
           if the Delta-CDF have different characteristics, and
           I think that should be researched.
                       DR. KRESS:  Well, I also felt that this
           was a one-way test, and that you took those components
           that were downgraded and did all of them with a factor
           of 10.  But you had 40,000 other components that you
           didn't do that to.
                       And if you did the FSER vesely and RAL
           correctly for group components, you may find out that
           some of those actually would have been risk
           significant; whereas, they weren't even -- you didn't
                       DR. SHACK:  The reason that you had a FSER
           vesely for a RAL was in the PRA.
                       CHAIRMAN APOSTOLAKIS:  Well, let me give
           you another example and a possible improvement.  Did
           you consider at all the idea -- and this question is
           addressed to South Texas -- of surrogate components
           like they use in risk-informed inspections?
                       DR. KRESS:  And that's what I had in mind. 
            You could surrogate some of those other 40,000.
                       MR. GRANTUM:  There are some components
           that are surrogate components when you look at the
           components like diesel generators that encompass large
           skid mounted equipment.
                       CHAIRMAN APOSTOLAKIS:  And how about the
           thousands of components that are not in the PRA?  Just
           like pipes are not in the PRA, but in the risk-
           informed inspection program, they consider -- well, at
           least the Westinghouse approach, considers the
           surrogate component.
                       So you look at the impact of the failure
           of that pipe on that component and that super
           component isn't in the PRA.  I mean, that is a lot of
           work, and you don't necessarily have to do it in your
           case.  But did you consider it at all?
                       MR. GRANTUM:  Yes, that has been
           considered whenever we have talked about the
           applications of risk-informed in-service inspection
           and that was in fact some of the discussion on how
           robust the categorization process was, because there
           was an issue about -- well, we contended that we did
           look at surrogate components.
                       And taking out a section of a pipe or
           several piping segments could be the same as assuming
           that the pump has failed, but have the same impact on
           the CDF.
                       CHAIRMAN APOSTOLAKIS:  And that is an
           inspection problem?
                       MR. GRANTUM:  Right.  But it is also in
           the PRA, because we had the FSER vesely of that
           component failing, which one could make an argument
           that the piping segments would be the same.
                       I would say that the staff had concerns
           about that because they indicated that they didn't
           think that accounted for dynamic effects; pipe failing
           and special interactions types of effects.
                       CHAIRMAN APOSTOLAKIS:  But the exemption
           request, this one, and not the risk-informed
           inspection program; did you do any of these surrogate
           component business?
                       MR. GRANTUM:  Not --
                       CHAIRMAN APOSTOLAKIS:  Or is it strictly
           based on the expert panel --
                       MR. GRANTUM:  It is based on the series of
           sensitivity studies that PRA comes up with a statement
           of the importance based on the 21 sensitivity studies,
           the working group combines the deterministic
           questions, and the expert panel approves that.
                       So the surrogate components that you are
           referring to weren't directly done as part of the
           categorization for this.
                       CHAIRMAN APOSTOLAKIS:  If I take a
           component that is not in the PRA, and the expert panel
           categorizes it based on the five questions, and there
           was no further analysis to see whether that component
           could belong to a bigger component that is already in
           the PRA so I could have some sense of what would
           happen if we do it the same way for the --
                       MR. GRANTUM:  Well, yes, we answered the
           five questions, and we are asking the question could
           it fail a function.
                       CHAIRMAN APOSTOLAKIS:  And then one could
           conceivably find the RAL for that system and somehow
           come up with an intelligent method that Tom is asking
                       MR. GRANTUM:  Right.
                       CHAIRMAN APOSTOLAKIS:  Again, this not
           something that you might have done, but that could be
           an improvement in the matter.
                       MR. GRANTUM:  Well, with a series of
           sensitivity questions, I would say the answer is yes. 
           I mean, for looking at all the questions that we
           asked, it is subsumed in those answers.
                       DR. SIEBER:  When I think what Dr. Kress
           said, that he could eliminate the sensitivity studies
           and have the proper definition of the thresholds for
           the importance measures, I guess then that I would
           object to that.
                       DR. KRESS:  I don't know if it is possible
           or not.
                       DR. SIEBER:  I think the regulatory basis
           -- what you are doing here is Reg Guide 1.174, and
           without the sensitivity studies, it can't apply.
                       DR. KRESS:  Oh, yeah, because you are
           bounding the delta, if they actually bond the delta,
           but I don't know if it is possible or not.
                       DR. SIEBER:  I guess you could, but I
           would still like to see it directly applied the way
           the regulation states, as opposed to --
                       DR. KRESS:  But you may not be able to do
           that all the time.
                       MR. HOLAHAN:  Those two could come
           together, if for example, you could calculate the
           Delta-CDF contribution at the component level, and
           then you simply add them up, and that is equivalent to
           doing the sensitivity study.
                       So you pick a bunch of small ones, but you
           make sure that the cumulative effect is still small.
                       DR. SIEBER:  Well, I guess I still don't
           believe that South Texas ought to get that rock in
           their knapsack.
                       DR. KRESS:  Well, I actually wasn't
           proposing that either.
                       DR. SIEBER:  Well, nobody is proposing
                       MR. GRANUM:  Dr. Apostolakis, I have been
           asked to clarify something.  There are comments over
           here that, no, we didn't explicitly go and take a
           component, and extrapolate out in the form of a super
           component to look at the impact of that.
                       On the other side of the coin, when we
           looked at a component deterministically, if it was
           going to fail a function or it would have failed a
           risk-significant function somehow, it would have
           gotten the same ranking as the highest significant
           function that it was associated with.
                       CHAIRMAN APOSTOLAKIS:  It was the panel
           that did this?
                       MR. GRANUM:  Right.  I wanted to clarify
           that, and I will allow my colleague here to further
           clarify that if you would like.
                       MR. SCHNIZEL:  Glen Schnizel, South Texas. 
           Now, again, if a component's model is in the PRA, we
           looked at it from the function standpoint, and if
           there are other components that are necessary to
           satisfy that same function, if those components would
           fail, they received essentially the same
           categorization as would the PRA reflected.  So, from
           that perspective, that is how we captured that.
                       MR. HOLAHAN:  Let me say something on this
           subject, and that is that I share some of the
           committee's concern, but not another part of it.
                       I am not a particular fan of FSER veselies
           and RALs.  I think there are a lot of limitations and
           difficulties with them, and I think there is room for
           improvement, and we ought to be encouraging that.
                       And I am supportive of that, and I think
           the fundamental goal is to identify components issues
           to be focused on, and also to be judging whether the
           small change standard in 1.174 is met.  I don't share
           the committee's concern over ossification.
                       DR. SHACK:  Well, Appendix T is the place
           where ossification is concerned.
                       MR. HOLAHAN:  Amen.  That's right.  I
           think before we get to that point that there is plenty
           of time to lay those issues out.  Plus, the way that
           we have been thinking of Appendix T, it would say that
           you can do it this way, or you can propose something
                       And the purpose of an Appendix T is to say
           we are sure that this is okay, and so you can do it
           without review and approval.  I don't see that the
           staff is in a mood or is not receptive to  new and
           good ideas.  The whole reason we are here is -- this
           whole thing is a new and different idea.
                       CHAIRMAN APOSTOLAKIS:  Well, what happens,
           Gary, until we have a new -- which could be some time,
           and let's say you have three other licensees, and they
           hear that South Texas was granted the exemptions, and
           they go line-by-line, and they try to reproduce what
           South Texas did.
                       Now, they might have problems because of
           the extreme redundance that those guys would get, but
           the --
                       MR. HOLAHAN:  That could happen.  As a
           matter of fact, we are granting this for Unit 1 and
           Unit 2.  I mean, so you already have two.  So what is
           wrong with that?
                       DR. POWERS:  Well, I'm ready to ossify
                       CHAIRMAN APOSTOLAKIS:  What?
                       DR. KRESS:  Too late.
                       DR. POWERS:  For the life of me, I have
           not seen anything here that is going to change or that
           causes any heartburn to people.  The only thing that
           looks at all suspectively is this business of okay,
           suppose I take a low safety significant component, and
           let's say it is dead and died.
                       And now I do the raw for the other
           components and one or two of them might come up, and
           we don't find that out.  We don't know that.  I don't
           know why we don't do that.  It seems like an easy job
           to do.
                       MR. HOLAHAN:  Except the number of
           combinations is astronomical.
                       DR. POWERS:  It is a modest common
           editorial problem.
                       CHAIRMAN APOSTOLAKIS:  It is modest when
           you want to calculate a number, but actually doing it
           is different.
                       DR. POWERS:  I am sure that these things
           could be imaginatively done.
                       MR. HOLAHAN:  This is getting simpler all
           the time.
                       DR. POWERS:  I mean, that seems to be the
           only thing that would represent a significant
           improvement in the technology.  Otherwise, I am ready
           to ossify.  Why not have somebody do it line by line.
                       CHAIRMAN APOSTOLAKIS:  Wait.  Wait.  Has
           anyone come to you yet or hinted that they might come
           with Option 2 exemptions request using the top event
           prevention methodology?  That is really different.
                       MR. HOLAHAN:  No.
                       CHAIRMAN APOSTOLAKIS:  Nobody has done
                       MR. HOLAHAN:  I have not heard that.  We
           have had discussions of the top event methodology in
           other contexts, and not as an exemption.
                       CHAIRMAN APOSTOLAKIS:  Well, that would be
           very different.
                       MR. HOLAHAN:  I have not heard it.  Tim
           Reid, have you heard anything?
                       MR. REID:  Top event prevention has been 
           discussed at some of our meetings, and those
           individuals have attended our meetings, but I haven't
           heard any exemption or any idea like that being
           proposed so far.
                       CHAIRMAN APOSTOLAKIS:  Okay.  Because that
           would be a very different approach.  Okay.  Thank you.
                       DR. SIEBER:  Any further questions?
                       CHAIRMAN APOSTOLAKIS:  Or comments.
                       DR. SIEBER:  If not, Mr. Chairman, I think
           we have concluded.  Thank you very much, and I thought
           it was very productive.
                       CHAIRMAN APOSTOLAKIS:  Thank you,
           gentleman.  Well, we are due for a break.  So we can
           go with a break.  We will recess until 3:35.
                       (Whereupon, at 2:53 p.m., the meeting was
           recessed, and was resumed at 3:35 p.m.)
                       CHAIRMAN APOSTOLAKIS:  We are back in
           session, gentlemen.  The last presentation of the day
           is by Mr. Sorensen, ACRS Senior Fellow, and he will
           talk to us about the general design criteria, and some
           work that he did the last few months for us.  Jack.
                       DR. SORENSEN:  Thank you.  This assignment
           actually had its genesis during the ACRS planning
           session, and the scope was basically to take a look at
           the Federal design criteria and Appendix B from the
           standpoint of their place in the grand scheme of
           things if one is going to risk-informed regulation.
                       There was sort of an underlying thought
           that Appendix A and Appendix B would be key to risk-
           informed revisions to the regulations, and that
           probably is not quite true.
                       The questions that I tried to address and
           will touch on in this presentation -- and in the paper
           which follows it -- are the GDC risk-informed as
           written, and the answer to that question is yes,
           insofar as that concept was understood at the time the
           criteria were written.
                       The second question is are they an
           impediment to risk-informing Part 50, and the answer
           to that is that some are, and many are not, and we can
           go through some examples of it later.
                       How can they be made risk-informed, and I
           have addressed that in a very general way, and in a
           somewhat naive way perhaps, but I hope in a way that
           will be useful.
                       And the final question today apply to new
           reactor types or non-light water reactors, and the
           answer to that is that some do and some don't, and I
           will try to touch on these.
                       The general design criteria as they exist
           right now, and have existed since about 1971, are 55
           individual criteria in six groups.  The overall
           requirements protection by multiple fission product
           barriers and protection and reactor control systems,
           and fluid systems, and reactor containment, and fuel
           and radioactivity control, and the scope and content
           of the individual criteria, vary very greatly from one
           to the next.
                       DR. KRESS:  What happened to 6 through 9?
                       DR. SORENSEN:  Funny you should ask that. 
           I think I actually touch on that in a later slide, but
           the earliest -- the GDC, as they exist now in Appendix
           A to part 50, were published in February of 1971, or
           incorporated into Part 50 in 1971.
                       The earliest version that I could find 
           was written in 1965, I believe.  I found a memo from
           Harold Price, who was then the Director of Regulation
           to the Commissioners, forwarding general design
           criteria for consideration.  There were 27. And the
           evolution of the criteria as far as I can tell was
           primarily in negotiation between the staff and the
           ACRS over a period of several years.
                       Following that 1965 version, I know that
           around 1969 that there was a version published for
           comment that contained 70 criteria, and they were
           numbered consecutively from 1 through 70.
                       When they were finally incorporated in
           Appendix B, some had been combined with others, and
           some had been dropped, and for reasons which are a bit
           mysterious, they tried to maintain something of the
           original numbering scheme.
                       So there are gaps in the numbering scheme. 
           They reflect the state-of-the-art in reactor design at
           the time that they were published, and when we get
           into looking at individual criteria that becomes very
                       Another observation is that they reflect
           the phenomenology important for light water reactor
           safety.  The early version that I mentioned, the 1965
           version, clearly made an attempt to cover other
           technologies that are references to unclad fuel,
           vented fuel, and other features that are not typical
           of light water reactors.
                       What evolved into the 70 criteria and
           later into the 55 is clearly focused on light water
           reactor technology, and indeed the introduction to
           Appendix A says that.
                       And the criteria contained 4 or 5
           different kinds of information, and in hopes that it
           might at some point be useful, I tried to characterize
           them in that sense.
                       Typically, each criteria either
           establishes a need for conservatism, a list of things
           that need to be accounted for, which I have decided to
           call completeness.  They call for a capability to be
                       They call for reliability of some of the
           systems or functions that are required, or they simply
           require a defense in depth feature of one kind or
                       In the package of material that I gave
           you, at the end of that, there is a spread sheet that
           summarizes all 55 criteria, and some of the different
           ways that I have tried to characterize them, though I
           don't plan to use that directly in the presentation. 
           But it might be a useful reference at some point.
                       I have also included in what I gave you
           verbatim copies of the text of Appendix A, the general
           design criteria, and Appendix B, the QA criteria, in
           case you want to refer to those.
                       In the introduction to Appendix A are the
           following major -- or what I would call the major
           points.  The application for construction permit must
           include the principal design criteria for the system. 
           That is a requirement in Appendix A.
                       And by implication one option would be to
           simply play back the general design criteria that are
           listed there.  The criteria to establish requirements
           for structure, systems, and components important to
           safety, and again this is from Appendix A directly.
                       Important to safety is defined as those
           systems, structures, and components that provide
           reasonable assurance of no undue risk; and what that
           means is that what we are dealing with in Appendix A
           is an adequate protection standard, because there is
           a legal equivalence established between the phrase,
           "No undue risk," and "adequate protection."
                       So the standard is not risk.  It is
           adequate protection.  And the criteria as written
           establish minimum requirements for water cooled
           nuclear plants.  That is specifically stated.
                       It is also stated that there are
           considered to be generally applicable to other types
           and can provide guidance in establishing criteria for
           other reactor types.
                       Appendix A also goes on to say, or the
           introduction goes on to say, that the development of
           the general design criteria is not yet complete, and
           that there are four issues enumerated that need
           further consideration, which are:
                       Single failures of passive components;
           redundancy in diversity requirements for fluid
           systems; type size and orientation of primary system
           breaks; systematic non-random concurrent failures or
           redundant elements.  As far as I know, those words
           have been since 1971 unchanged.
                       Also, within the introduction there are
           two exceptions listed, the first two points on this
           slide.  The introduction specifically says that the
           general design criteria may not be sufficient for some
           plants, in which case the applicant is expected to
           propose additional criteria.
                       And it also says that some general design
           criteria may not be necessary for some plants, and
           again the applicant is in principle to propose his own
                       One observation that is kind of
           interesting is that we really don't know without
           examining individual license conditions to what degree
           the operating plants comply with the general design
                       Over half of the currently operating
           plants received their construction permits before the
           GDC were made part of Part 50.  There are some
           important definitions in Appendix A, and specifically
           definitions for loss of coolant accidents, which that
           has been discussed in a number of presentations today,
           earlier, and in the previous couple of days.
                       And they define loss of coolant accident
           as including all pipe breaks up to and including the
           double-end break of the largest pipe in the system. 
           There is a definition for single failure and there is
           a definition for anticipated operational occurrences. 
                       So those phrases are self-supported within
           the appendix.  Before we get into this possible
           specific changes to Appendix A, I think there is some
           observations that are worth making.
                       One is that past regulatory reform
           efforts, and I am thinking specifically of the
           marginal safety program that was conducted during the
           1980s, and the regulatory review group in the early
           '90s, judged the GDC to be important to safety and to
           not be a significant burden, insofar as the regulatory
           structure was concerned.
                       In support of that thought, one can
           observe that there are 160 division one regulatory
           guides, and of those, 129 support some aspect of one
           or more of the general design criteria.
                       I think an additional 10 of those are QA
           related, which in a sense also supports the GDC,
           because the first criteria is a QA criteria.  Part 50
           incorporates a lot of material by reference.  So
           specifically the ASME code, Sections 3 and 11, and I
           think Section 8 now as a matter of fact.
                       Several IEEE standards, and so the GDC are
           a relatively small part of the total volume of
           regulation that one has to deal with, and in reality
           risk-informing the GDC only makes sense in conjunction
           with other changes in the regulations.
                       The reason for making particular note of
           that is that from this point on, and in order to keep
           the scope of what I was doing reasonable, I had looked
           basically at the GDC in isolation.  I didn't try to
           look at all the tentacles from each of the criteria.
                       There are basically three options for
           risk-informing the general design criteria.  The first
           and simplest is to modify the scope, and I will give
           an example of that in a second.
                       The second is to modify the individual
           requirements.  The third is basically to replace the
           GDC as a body with safety goals, and/or risk
           acceptance criteria, and move something like the GDC
           into the realm of guidance documents.
                       What I mean by modifying the scope is
           something akin to what the approach that the staff is
           taking on Option 2 for risk-informing special
           treatment requirements.
                       As we will see in a minute, a number of
           the criteria incorporate the term, important to
           safety.  Equipment important to safety must be treated
           in a particular way.  The simplest change you can
           envision is replacing that phrase or redefining it
           with perhaps the phrase, "important to risk."
                       And then you have to agree on what that
           means.  One possibility, of course, is to use the
           risk-informed classification safety class scheme that
           the staff has come up with as part of Option 2, where
           one might put risk one and risk two components into
           the important to risk class, and then subject them to
           the criteria, and whatever special treatments that is
           implied there.
                       And we will look at some examples of where
           that might be the case.  The second element or second
           option, modifying the individual requirements, is
           similar again to what the staff is doing in Option 3
           to risk-inform the technical requirements in Part 50.
                       And where you look at each regulation,
           each provision, each design criterion, and try to
           determine how it might be changed to improve its risk
                       There is actually a number of things that
           you can do there.  The simplest thing is to look at
           the criterion and tender to find the minimum change
           that you have to make to shift the focus from
           important to safety, or safety related, to important
           to elements important to risk, but not change the
           basic intent of any of the requirements.
                       CHAIRMAN APOSTOLAKIS:  I thought in Option
           2, Jack, when the staff speaks of the importance to
           safety, they really mean work risk.
                       DR. SORENSEN:  Yes.
                       CHAIRMAN APOSTOLAKIS:  Tool safety
           significance components is really low risk
                       DR. SORENSEN:  That's correct.  They  have
           come up with this four box scheme.
                       CHAIRMAN APOSTOLAKIS:  That's right.
                       DR. SORENSEN:  But I think the path
           involves actually changing the words, because they
           didn't want to -- they do not want to have important
           to safety to mean one thing for people who have not
           adopted risk-informed options, and another thing for
           applicants who have.
                       CHAIRMAN APOSTOLAKIS:  It is a mystery to 
           me why they went that way, although you might say that
           core damage is not really risk.  It is core damage
                       And to say something is an important risk
           because it is core damage, most likely it is, but
           strictly speaking, it is not risk.  It is
           categorization.  But what is confusing, of course, is
           that they talk about safety related, and the
           importance to safety.  They are two different things.
                       DR. SORENSEN:  And as far as the path they
           are on in Option 2 as I understand it, they are kind
           of taking those two definitions -- important to safety
           and safety related, and then replacing them with the
           words, "important to risk" in certain of the
                       And using this four box scheme to classify
           components, the systems and components that are
           important to risk.  Okay.  So that is a second way of
           doing this and modifying individual requirements is
           actually going in and rewriting every requirement in
           risk terms, which one could do.
                       And the third possibility would be to go
           a step further and not only rewrite them, but make
           them technology independent.
                       One of the projects that NEI has embarked
           on is to have by the end of the year a proposed draft
           of general design criteria that are technology
           independent.  I am going to be interested to see what
           they come up with.
                       CHAIRMAN APOSTOLAKIS:  Did they give us an
           example yesterday?
                       DR. SORENSEN:  Well, in Adrian Haymer's
           presentation yesterday or the day before, he had one
           example which was kind of an easy one.  I mean, he
           picked one of the easy ones, and as Dana observed I
           think in one of the sessions on Monday, at some point
           you have got to talk about the phenomenology, and it
           is a question of whether you talk about that in
           something called the design criteria, or someplace
           else, but it is obviously very hard.
                       CHAIRMAN APOSTOLAKIS:  Are these criteria
           sort of principles of good practice when you design
                       DR. SORENSEN:  Some of them are, yes.
                       CHAIRMAN APOSTOLAKIS:  So you can't really
           replace them --
                       DR. SORENSEN:  Well, it is a question of
           where you put them, I think.  If I were starting over,
           a lot of them I would adopt pretty much the way they
                       Whether I left them as part of the
           regulations, and whether I put them in the guidance
           documents is another question.
                       CHAIRMAN APOSTOLAKIS:  Well, the ones that
           refer to, for example, to water, and design, and so
           on, I don't see how one could put those in a safety
                       DR. SHACK:  Well, commensurate with the
                       DR. SORENSEN:  Yes, most designers do not
           start with a blank sheet of paper.  They start with
           something that has worked in the past, and good design
           practice evolves in any technology.
                       CHAIRMAN APOSTOLAKIS:  How about in a
           purely risked-based, or risk-based, it seems to me
           that there would still be a place for something like
           the general design criteria.
                       DR. SORENSEN:  Absolutely.  Somebody will
           have to go from your regulatory requirements to a set
           of design criteria that a designer can work to.  You
           can't just hand the safety goals to the designer of
           every system in the plant and say, okay, come up with
           a design.
                       At some point, you have got to allocate
           your safety budget amongst systems, and whether you
           like risk allocation or not, that happens at some
           point in the design process, and it is just a question
           of how.
                       So you have got to have a place to start,
           and I think there is a fairly good argument  for these
           general design criteria or something very much like
           them being or staying as part of the regulatory
                       This may become a little bit easier to
           talk about when we look at a couple of specifics.   I
           don't have any particular or any specific proposal to
           offer with respect to replacing the GDC with safety
                       Conquest, a couple of months ago, I guess,
           when I was trying to get some advice from him on how
           to proceed with this project, came up with an E-mail
           proposal that I think he sent to everybody involving
           risk-accepted or safety goals, and risk-acceptance
                       I think that would certainly work, but
           somewhere in this hierarchy of design documents, you
           have to have something equivalent to the general
           design criteria.
                       Just a couple of other thoughts, and then
           we will look at some individual criteria.  Going back
           primarily to Option 1 and changing the scope.
                       Of the 55 criteria, 13 of them have a
           scope that is now defined as important to safety, and
           with a change of a couple of words could be redefined
           in terms important to risk, and change virtually
           nothing else, and have I think a good impact.
                       The single failure criterion which was
           mentioned in this morning's presentation appears
           specifically in nine of the criteria, and if you
           decide what to do about it in the context of one of
           those criterion, you could probably make a similar
           change in others.
                       But that is basically a reliability
           consideration, and there are probably better ways to 
           state that now than the single failure requirement. 
           And overall 13 could be changed from important to
           safety to important to risk.
                       And 30 probably would require no change,
           although I think all of these judgments are arguable
           at this point; and 19 could be recast in risk terms by
           looking at the individual requirements.  And I think
           now I would like to go to  looking at a couple of --
                       DR. WALLIS:  I was wondering about that. 
           There are many things that are important to safety
           which aren't included in risk, if you think of risk as
           being simply a typical PRA.
                       There are other things that have some
           effect on safety.  That is always the problem.  I
           think risk is only interpreted in terms of PRAs.
                       DR. SORENSEN:  Yes, and in my thinking on
           these, those are the terms that I was thinking in. 
           Some of these you might examine closely and decide
           that you don't want to change important to safety to
           important to risk.  I'm not sure.
                       But in a first reading or a second reading
           even, it looked to me that that would be a
           straightforward change.  And there is one other point
           that I wanted to bring up.
                       In terms of applicability to non-light
           water reactors, there is 36 of them that are probably
           applicable to virtually all reactor types, and there
           are 19 that probably are not applicable to some
           reactor types.
                       And again I think that judgment is in the
           case of some criteria could go either way.  Some of
           them are clearly general, and some of them the intent
           applies, but you might end up with an inappropriate
           word in the criterion, a reference to cladding, for
           example, where you might in fact not be dealing with
           clad fuel.  And I will try to touch on these in the
                       Okay.  A good example of criterion -- this
           is not in your slides, but in the text of Appendix A
           immediately behind the slides, you will find each of
           the criteria.
                       And the significant words here from a risk
           standpoint, and I think this is one where you could
           change important to safety to important to risk, and
           perhaps improve the focus.
                       DR. SORENSEN:  What is this thing tsunami? 
           What is it?
                       DR. SORENSEN:  Tidal wave.  The source may
           be different.
                       DR. POWERS:  It is on a lake isn't it?
                       DR. SORENSEN:  You're right.  One is an
           ocean and one is a closed body of water.  This one, I
           think simply changing the scope would be pretty
           straightforward.  I am not sure that the changes that
           were in Haymer's examples provide much benefit
                       DR. POWERS:  Well, he left that nice
           prepositional phrase, "With sufficient margin."
                       CHAIRMAN APOSTOLAKIS:  So what was the
           difference with yesterday?
                       DR. SORENSEN:  I should have brought that
           with me and I did not.  I'm sorry.  Basically, the
           three numbered points have been combined and
           generalized in some way, which I have now forgotten. 
           I apologize for not bringing that along.
                       CHAIRMAN APOSTOLAKIS:  So what would you
           do to this one?
                       DR. SORENSEN:  I would simply take the
           phrase, "important to safety," and replace it with
           "important to risk."  And use whatever definition of
           risk that I had decided to use in my regulations in
           general.  I think the staff proposal --
                       DR. POWERS:  It seems to me that this is
           where the absolute has to be confronted.  I think you
           have to come in and address the absoluteness here.
                       DR. SORENSEN:  Well, my thought on that,
           Dana, was that in fact is done in the numbered points,
           where it says, appropriate consideration.  I saw those
           words as softening the requirements in the first
                       DR. POWERS:  I see that as non-helpful,
           because you come down and say, well, how do I define
           appropriate.  Well, I define that based on risk.  I am
           still stuck with the problem that I can at any site,
           if I am willing to go back far enough in the
           geological history, I can find an earthquake that the
           planet simply cannot withstand, that no structure
           could ever withstand, because far enough back there
           were some pretty horrendous earthquakes.   So it seems
           to me that the absolute term here shall be designed to
           withstand has to have something in it that puts it
           within the context of some sort of probability here.
                       DR. SORENSEN:  I guess it was not clear to
           me that that had to be done here, as opposed to
           someplace else in your regulatory structure.
                       CHAIRMAN APOSTOLAKIS:  What I would
           suggest is that this would be eliminated in a risk-
           informed, because you would naturally consider the
           contribution from --
                       DR. POWERS:  Well, it is the naturally
           part that I have a little trouble with.
                       CHAIRMAN APOSTOLAKIS:  Why?
                       DR. POWERS:  It is not so obviously to me
           that that would be natural.
                       CHAIRMAN APOSTOLAKIS:  In a PRA?
                       DR. POWERS:  In a PRA, and I use that --
           I substantiate that by pointing out that in all of the
           applications of 1.174 that have been presented to the
           committee, when they go to set the horizontal access
           value, the CDF value, they don't use the seismic
           contribution of risk.  They have not at any time that
           we have come up here.  And when asked to do that, they
           said, oh, it moves it up a little bit.
                       CHAIRMAN APOSTOLAKIS:  If you read Option
           2, they do refer to it.  They do.  And they say the
           reason why they did the --
                       DR. POWERS:  George, I am saying that it
           is not natural.  I am not disagreeing with you that
           there places where it says take into account seismic
                       CHAIRMAN APOSTOLAKIS:  But we are
           confusing now two issues.  What I am saying is that in
           a risk-informed licensing regulatory system --
                       DR. POWERS:  You would want to have a
           design criteria that said that shall make it natural
           to include seismic contributions to risk.
                       CHAIRMAN APOSTOLAKIS:  No, no.  This says
           design, and what I am saying is that if it is risk-
           informed, you are going to have -- if you submit a PRA
           that does not have external events, and you are
           regulating on the basis of core damage frequency or
           something else, then that PRA would be unacceptable.
                       In fact, all three refer to the load from
           the earthquake and not the strength.  So you still
           have the problem with what does withstand mean.
                       DR. SHACK:  Let's put it this way. 
           Lawyers have not interpreted this to mean that you
           have to withstand the effects of tectonic plate
                       DR. POWERS:  The problem is that it is
           like an EPA criterion.  The better I get at my
           geology, the more that historical record in fact is
           appropriate and it seems to me that appropriate
           consideration gets me out of it.
                       DR. SORENSEN:  Possibly.
                       DR. POWERS:  But, George, that is not
           useful unless you tell them what a good PRA is.  That
           is what the good general criteria would be for a PRA.
                       CHAIRMAN APOSTOLAKIS:  Well, it would
           state all modes of operation and contributors and all
           causes of failure.
                       DR. POWERS:  If you say those things, then
           no PRA is adequate, because no PRA currently takes
           into account sabotage, and that is clearly
                       CHAIRMAN APOSTOLAKIS:  And I would exclude
                       DR. SORENSEN:  This is fairly typical of
           the discussions that one would get into in virtually
           every one of these.  I would with your permission 
           move on to a couple of examples.
                       CHAIRMAN APOSTOLAKIS:  Sure.  So we can
           repeat the arguments.
                       CHAIRMAN APOSTOLAKIS:  The PRA doesn't
           tell you that you should design things to the quality
           standards that industry has, and the PRA will just
           assess the risk, and since we were told that there is
           no difference between --
                       DR. SORENSEN:  Well, I think the function
           of something like the general design criteria in a
           risk-informed system is the same as it is in the old
           deterministic system.  It is to give the designer a
           road map, a path that he can go down and be reasonably
           assured that he will end up with a design that is
                       CHAIRMAN APOSTOLAKIS:  Is it general
           principles or a road map?  There is a difference,
                       DR. SORENSEN:  Well, a road map is perhaps
           the wrong word.
                       CHAIRMAN APOSTOLAKIS:  Is it the
           constitution or is it the law?
                       DR. SORENSEN:  But I think you can
           establish a hierarchy of design documents that
           includes the regulations at the top here, and then
           going down perhaps to the next step, something like
           the general design criteria, and then to industry
           codes and standards.
                       And functional requirements and so forth,
           and I think that something like this belongs somewhere
           in that hierarchy, and whether you put them into the
           regulations or you put them someplace else is probably
           not of great import.
                       Part of what is embedded here is a list of
           all the things that the designer has got to take into
           account if he is going to end up with an acceptable
                       CHAIRMAN APOSTOLAKIS:  Right.  And that's
           doing a good PRA.
                       DR. SORENSEN:  In a sense it is a
                       DR. POWERS:  But is this guidance for the
           designer or for the PRA guy?
                       CHAIRMAN APOSTOLAKIS:  No, the designer
           must know that eventually his design would be
           subjected to a PRA, and go back and forth.  So he has
           to know.
                       VICE CHAIRMAN BONACA:  Well, many of these
           criteria actually are defense in depth.
                       DR. SORENSEN:  There is five that I see
           that where the primary purpose is defense in depth,
           and there is another half-a-dozen where there is an
           embedded defense in depth requirement; and then there
           is quite a few where defense-in-depth is perhaps the
           underlying thought.
                       The second one that I wanted to take a
           quick look at was environmental and dynamic effects
           design bases.  Again, this is a list of things that
           the designer has to take into account.
                       But the thing that I especially wanted to
           take note of here is that this is one of the few
           criterion that has been modified since 1971, and
           specifically the however, "however, dynamic effects
           associated with postulated pipe ruptures," and so
                       And this obviously is the leak before
           break consideration.  The only other one where the
           criterion itself has changed is control room
           criterion, which we will get to later, but that was
           changed to accommodate the new source term.  But this
           has the same kind of arguments that I think --
                       CHAIRMAN APOSTOLAKIS:  Is there a
           criterion that says or refers to human error?
                       DR. SORENSEN:  No.  These are design
                       CHAIRMAN APOSTOLAKIS:  Well, the control
           room design affects human error.
                       DR. SORENSEN:  Possibly.  But the straight
           answer to your question is no.
                       CHAIRMAN APOSTOLAKIS:  Well, the point
           that I am making is that if you start writing down
           GDCs and trying to figure out dynamic effects, and
           this and that, you are going to be incomplete, because
           you can't predict everything.  So that's where you
           make a blanket statement and whatever is important.
                       DR. SORENSEN:  But again between that
           statement and the designer executing the design has
           got to be something like this that lists everything
           that you know about it.  You don't want them leaving
           out things.
                       CHAIRMAN APOSTOLAKIS:  If I do a PRA
           wouldn't I naturally consider dynamic effects?
                       DR. POWERS:  None of them do.
                       CHAIRMAN APOSTOLAKIS:  Gus, you are so
           unfair.  The good ones do.  This is called spacial
           common cause failure analysis.  We did it for Indian
           Point, for heavens sake, 20 years ago.
                       DR. POWERS:  How many other PRAS have it
           in it?
                       CHAIRMAN APOSTOLAKIS:  Well, I can't, but
           in fact people have experimented at that time using
           the sense code that were developed, and you ended up
           with something that was three feet high.  It is the
           spacial analysis that you do for fires, for floods,
           for dynamic effects.  Sure, otherwise it is not a good
           PRA.  I am talking about 20 year old technology now.
                       DR. SORENSEN:  Okay.  Criterion 5.  This
           one is interesting for primarily because it is the
           only one that I saw by inspection that is probably
           counterproductive as far risk information is
                       The decision of what functions to share or
           not share seems to me to be exactly the kind of
           question that modern PRAs could help answer, and this
           criterion as written biases the designer against
                       It is kind of interesting to note that in
           the Manshan station blackout event of a month or two
           ago, one of the options that was not available to the
           operators was to cross-connect the unit one diesel
           with unit two.        And the reason was that that
           plant was built to the general design criteria.
                       That particular plant was built to satisfy
           Part 50.  Those were the criteria that they adopted. 
           And it was noted in the one of the incident analysis
           reports that I read that they did not have the option
           of cross-connecting the units.
                       DR. WALLIS:  Well, why not, because it
           would actually help the orderly shutdown and cool down
           of the remaining units.
                       DR. SORENSEN:  Well, this criterion biases
           you against establishing that connection.
                       DR. WALLIS:  Unless it can't be shown.
                       DR. SORENSEN:  So the designer, to satisfy
           this easily, says don't do it.
                       DR. WALLIS:  And doesn't read the rest of
           the sentence.
                       DR. POWERS:  Well, if you are a designer,
           you are sitting there saying I can do one job or I can
           do two.  Gosh, let me think.  Which should I do.
                       DR. SORENSEN:  Obviously, we have 55
           criterion, and we are not going to get through all of
           them.  I will try and finish up in the next few
           minutes, but let me touch on one that I think is the
           next one, which I think is probably all right the way
           it is written.  I am not sure that I would change that
           from a risk-informed standpoint.
                       Basically what it says is that you
           shouldn't have a design that is going to incur fuel
           damage during normal or anticipated operational
                       DR. POWERS:  And that is where you get
           into a risk problem again.  Is something that has some
           probability of occurring an anticipated operational
           occurrence.  At the time that these were written that
           meant something that would happen in the lifetime of
           the plant.
                       DR. SORENSEN:  Right.
                       DR. POWERS:  Do you want to extend that
           definition as you move into a risk-informed
           environment, and if you do, then you run into an
           absolutism problem.
                       DR. SORENSEN:  I think you have to reach
           for it.
                       DR. POWERS:  A little bit.
                       DR. SORENSEN:  But if I understand your
           comment, the underlying concern is really dealt with
           in other criterion here.  I mean, it becomes evident.
                       DR. POWERS:  It could be, but what I am
           saying is a lot of this have this anticipated
           operational occurrence phrase in now, and we knew from
           the definitions someplace that that means within the
           lifetime of the plant.
                       DR. SORENSEN:  Right.
                       DR. POWERS:  It is a 10 to the minus 2
           probability.  Do you in a risk-informed world want to
           extend that, and say that okay, rather than having an
           absolute thing for anything that is 10 to the minus 2,
           have something that has some sort of a rated
           characterization for incredible, which I am reliably
           informed now is 5 times 10 to the minus 7.
                       DR. SORENSEN:  I think you are reading
           more into this criterion than I would read into it,
           but as I noted earlier, we can generate these kinds of
           discussions on virtually every one.
                       CHAIRMAN APOSTOLAKIS:  The last line there
           doesn't belong, anticipated occurrences.
                       DR. POWERS:  What it is saying is that you
           are precluding something or certain kinds of high
                       CHAIRMAN APOSTOLAKIS:  Right.
                       DR. POWERS:  Well, there is nothing wrong
           with that.
                       DR. KRESS:  This is one of those things
           where I keep talking about high frequency, lower
           fission product release.
                       DR. POWERS:  Well, you can imagine doing
           something that says, okay, with a high confidence
           level, which we could define as 95 percent or any
           other number, you precluded.
                       Or we could also take it and say now you
           preclude it, but the confidence level and reliability
           of doing it varies as the probability goes down from
           this 10 to the minus 2 level.
                       DR. KRESS:  Well, if you had the FC curves
           as the regulatory thing, it would automatically do
                       DR. POWERS:  They could do that for you,
                       CHAIRMAN APOSTOLAKIS:  It seems an option
           that it does not ask for margins.   But ultimately it
           seems to mean in a risk-based system that it would be
           a combination of margins and defense in depth that
           would give you the wrong numbers.  They are not
           separate things.  I don't see why you should limit
           yourself to the anticipated occurrences.
                       VICE CHAIRMAN BONACA:  Well, this was
           purely a word that was tied to it that meant it would
           happen 40 years ago in an operation.
                       DR. SORENSEN:  Okay.  Well, let's take a
           look at another one that is interesting, and this one
           I think is a clear illustration of how these criterion
           reflect the state of knowledge at the time.
                       I have never understood why this one
           exists.  It seems to me that it is completely covered
           by Criterion 10, which we just looked at, and I think
           the answer is that the phenomena had become of
           possible power oscillations and spacial power
           oscillations in large cores had become recognized in
           the preceding few years.
                       Interestingly enough the 1965 criteria,
           the earliest version that I found, that this was not
           addressed specifically in power oscillations.  It was
           addressed to process variable oscillations, which
           would include flow, for example.
                       DR. WALLIS:  Isn't this just another
           anticipated operational occurrence?
                       DR. SORENSEN:  Yes, I would consider that
           this is completely covered by Criterion 10, which
           preceded it.  But I thought it was an interesting
           example of reflecting the state of the art.  I guess
           we have time for one or maybe two more.
                       DR. KRESS:  What does it say about
                       DR. SORENSEN:  Okay.  That is the next one
           that I thought that I would look at.  Actually, there
           is probably 12 separate criteria that deal with
           containment, and the basic requirement is here;
           "Reactor containment and associated systems shall be
           provided to establish an essentially leak tight
                       And this is one of those where clearly
           there is some advocates of some reactor types that say
           this should not apply.  I would suggest that if we
           were starting over for light water reactors, we
           probably would not want to specify essentially leak
           tight containment the way this one does.
                       You may want to allow other concepts since
           the early containment failures seems to dominate risk
           as far as we already know.
                       DR. POWERS:  What this does is preclude
                       DR. SORENSEN:  Yes.
                       DR. POWERS:  And when you preclude
           confinement, then you are condemning yourself to
           eventually having an uncontrolled release in the event
           of an unmitigated accident.
                       DR. SORENSEN:  This would as worded would,
           yes.  Of course, the containment bypass, you have to
           deal with containment bypass sequences anyway.
                       But this is one that I think I would give
           some thought to, and I would hasten to add that I
           don't have the expertise in either PRA or severe
           accident phenomenology to know how to rewrite it.
           I just suspect that if you were to redo the GDC that
           you might decide to rewrite this one.
                       This criterion, of course, is supported by
           another 12 or 15 criteria that deal with containment
           related phenomena and containment heat removal,
           atmospheric cleanup, and penetrations, and isolations,
           and system isolation, and so forth.
                       But this is pretty unequivocal as to what
           is needed.
                       DR. KRESS:  Mine would have been very
           equivocal.  I would have said thou shall provide a
           reactor system such that the frequency is at least to
           a 95 percent confidence level.
                       CHAIRMAN APOSTOLAKIS:  Well, yes, some
           language like that, because that allows you to take
           credit for the release that you want.  The probability
           of it.
                       DR. SORENSEN:  Just as a last offering
           here, I would suggest looking at Criterion 17 on
           electric power systems.  This is the first one where
           the single failure criterion is specifically invoked,
           and the first one that you come to if you go through
           them in numerical order.
                       It is also, I think, the longest of the
                       CHAIRMAN APOSTOLAKIS:  Does a single
           failure have a definition somewhere?
                       DR. SORENSEN:  Yes, it is defined up in
           the introduction in terms of inability to perform the
           specified safety function.
                       CHAIRMAN APOSTOLAKIS:  If what happens? 
           If it fails?  Assuming a single failure.
                       DR. WALLIS:  If you have a hundred
           batteries, that means that one battery will disable
           the safety function that you are trying to deal with?
                       DR. SORENSEN:  Yes.  But the other thing
           to note here is that this gets to be a very specific
           criterion, electric power supplied by two physically
           independent circuits.
                       You can have a common switch yard, and
           that is acceptable.  There are underlying assumptions
           as to where the unreliability is, or where the risk
           might be.
                       And again this seems like a perfect
           candidate for recasting, in terms of a reliability
           goal that could be supported by modern risk analysis
           techniques.  I would not attempt such a wording.
                       VICE CHAIRMAN BONACA:  Jack, if we could
           go to Criterion 55.
                       DR. SORENSEN:  Sure.  You are talking
           about monitoring releases.
                       VICE CHAIRMAN BONACA:  No, it is one that
           tells you that you would have penetrations of pipes
           that would be -- well, it --
                       DR. SORENSEN:  Well, that is clearly one
           that I think you might end up rewriting in terms of
           risk considerations.  It is very specific.  In fact,
           criteria 50 through 55 I think you would rethink in a
           risk-informed environment.
                       CHAIRMAN APOSTOLAKIS:  No, the question
           here is what do we do with all of this?  I mean, we if
           have Commissioner Diaz come down here and talk to us,
           are we going to write a letter, or how does the
           committee feel about this?  And if we write a letter
           to whom do we address it and why?
                       DR. SORENSEN:  I have a couple of thoughts
           that might go in to the committee's thinking on this.
                       CHAIRMAN APOSTOLAKIS:  Go ahead.
                       DR. SORENSEN:  One is that it seems to me
           that Appendix A, and Appendix B for that matter, are
           not keys in any significant way to risk-informing the
           body of regulations.  They are a part of it, but they
           are no more important than a lot of other things.
                       So I think sort of the underlying
           implication in Commissioner Diaz's comments that they
           were key to proceeding I think is simply not right.
                       CHAIRMAN APOSTOLAKIS:  But you also I
           think claim that you could not risk-inform the
           regulations unless you go back to the GDCs and change
                       DR. SORENSEN:  That is probably true.
                       DR. POWERS:  And I agree with him on this. 
           If I look at Part 50, and I imagine anything in there
           that is changed to be somewhat risk informed, and I
           say now what do I do different, it ends up that I do
           nothing different, because I get controlled by the
                       And if you hit this one first just to get
           it out of the way, then you can go and look at the
           regulations and know that you are not going to run
           contrary -- you are not going to get into this mouse
           trap, and where the guy does nothing different.
                       CHAIRMAN APOSTOLAKIS:  So what would be a
           wise course of action for this committee; to raise the
           issue with the Commission or support Diaz?
                       DR. POWERS:  Well, it depends a little bit
           on how aggressive you want to be.  It seems to me that
           your options vary.
                       CHAIRMAN APOSTOLAKIS:  Well, should this
           be part of Option 3?
                       DR. POWERS:  Well, it is part of Option 3.
                       DR. SHACK:  It should be, but it is just
           that they have prioritized it in a different way. 
           They have chosen to do it a different way.
                       CHAIRMAN APOSTOLAKIS:  So does the
           committee feel otherwise?
                       DR. POWERS:  Well, right now they have got
           them -- I mean, we don't know what they are going to
           come back with, but they seem to have themselves in a
           conundrum on 46.  They are going to try to get out of
           it, but I don't see how to get out of it with the
           approach they are taking, but maybe they will.
                       But if they are going to continue to be
           boxed on 46, it seems to me that you go the other
                       CHAIRMAN APOSTOLAKIS:  What does that mean
           for us now?
                       DR. POWERS:  Well, that is one way to
           approach it, is to ask the staff what they are going
           to do about that, and then engage in these debates
           that Jack wants to cut off.
                       The other approach it seems to me is that
           you go through and say pick the juicy, easy ones.  And
           there are a couple of them.  I think 17 and a couple
           of others in there that seem particularly ripe to make
           risk-informed, and send the Commission a letter and
           say, gee, we can do these, and do one for them.
                       CHAIRMAN APOSTOLAKIS:  Well, we really
           shouldn't write a letter without hearing more.  We
           have to give them an opportunity.
                       DR. SORENSEN:  Both Option 2 and Option 3
           will, if pursued to their logical conclusion, will end
           up touching the GDC.  In Option 2, in the first sense,
           I talked about changing the scope in some way, and in
           Option 3, in changing individual requirements, and
           which you have no way of knowing right now is how many
           actual changes they will end up recommending.
                       Now, my own thought is that the option
           three process in particular is biased against making
           changes to the GDC.  The process starts with what they
           call the defense in depth concept or philosophy, and
           it doesn't lead easily to specific changes.
                       And that's because defense in depth rules
           that framework, and I think there is a little more
           hope for option two.
                       CHAIRMAN APOSTOLAKIS:  Well, they
           interpret defense in depth differently.  It is their
           justification for failing for different values, which
           as releases and core damage, and so on.  I don't think
           this is the kind of defense in depth they refer to.
                       DR. SORENSEN:  You may well be right.  My
           reading of the framework document is that the process
           ends up being biased against change.
                       CHAIRMAN APOSTOLAKIS:  Okay.  So that
           brings us again to the question; what do we do now?
                       DR. SORENSEN:  But clearly the staff would
           argue that they are on a path where both option two
           and option three deal with some aspect of this, and
           will presumably come to some recommendations to the
                       VICE CHAIRMAN BONACA:  It seems to me that
           some individual applications, unless you deal with
           some of the principles, you have no idea if you are
           still going to have the confusion like here.  And it
           seems to me that if you want to have a radical
           rewriting on a risk-informed basis, you should start
           from the top, and first attempt to see how they could
           be converted to risk-informed criteria.
                       CHAIRMAN APOSTOLAKIS:  Well, is it worth
           doing this now, or do other things that are more
                       DR. SHACK:  Well, what do you gain if your
           goal is ultimately to have a whole new risk-informed
           regulatory system.  If you are looking at the moment
           to try to identify the things that have the largest
           impact on safety and reduce regulatory burden,
           unnecessary regulatory burden, I am not sure that
           starting with the GDCs would rank terribly high on
           that list.  They never show up on the NEI --
                       DR. KRESS:  I think risk-informing the
           GDCs, I agree with Bill first that what he just said,
           that risk-informing the GDCs probably is important for
           the advanced reactors, if they ever have one.
                       That's where there is a collision, and a
           discontinuity in things, and what I would -- my choice
           of things would be to don't do these one at a time,
           except in the context that Bill said, where you are
           trying to -- you have picked the ripe ones, and you
           see where you have to change the GDCs so they are not
           in conflict.
                       And you do that like they are progressing,
           and to have a parallel effort, and have somebody say
           I want to rewrite these GDCs completely, starting from
           a blank page.  This was my recommendation to Jack
           actually when I wrote it.
                       And I would start out with writing down
           all my regulatory objectives that I want to achieve,
           and figure out to do them in a risk-based way that
           includes the prior definition of defense in depth, and
           the proper use of uncertainties, and to cover the
           whole range of fission product releases that I am
           interested in.
                       And I would work my way down on how do I
           achieve this type of design that would meet this
           criteria by specifying it in a risk-based way, but
           risk-informed because I am going to have a proper
           definition of defense in depth.
                       And end up with a whole new set of design
           criteria that are not very prescriptive like this, but
           may end up saying things like redundancy and
           diversity, and may even have things like you shall be
           sure to be able to shut down the reactor, and you may
           be sure to have emergency cooling.  You may be sure to
           have long term cooling.
                       You may have things like that in it which
           are --
                       CHAIRMAN APOSTOLAKIS:  So what you are
           saying is that the Gen-4 guy --
                       DR. KRESS:  Yes, put this off to the Gen-4
                       CHAIRMAN APOSTOLAKIS:  But NEI told us
           that they are working on these things, and they would
           have something by December.
                       DR. KRESS:  Yes, but I suspect they are
           going to pick out --
                       CHAIRMAN APOSTOLAKIS:  But that might be
           the first good opportunity for us.
                       DR. KRESS:  To have a letter, yes.  But I
           am in favor of sort of approaching it like Bill said.
                       VICE CHAIRMAN BONACA:  But looking at the
           other side, you know, if you leave this stuff behind,
           I agree they are more important to certainty if they
           have priority in many ways, and it seems to me that
           ultimately we are going to have patch work to patch
                       DR. KRESS:  That is exactly what we are
           doing.  That's why I wanted to have a parallel effort
           to get away from that.
                       DR. POWERS:  There is a perception,
           George, that these things are past history.  They are
           not.  I mean, GDC-3 is actively invoked regularly.
                       CHAIRMAN APOSTOLAKIS:  But I think in Bill
           Shack's world that that would be singled out where
           they try to reach some benefits by risk-informing fire
           protection requirements.  So the question is should we
           do it as the need arises or shall we have an all out
           attack of the GDCs?
                       DR. POWERS:  Well, it seems to me that
           coming in that you have got two approaches.  The staff
           chose an approach and now you are boxed.  They are
           getting boxed right now.
                       DR. KRESS:  It may not work is what you
           are saying.
                       DR. POWERS:  Well, if their approach is
           not going to make substantive program progress, it
           seems to me that the alternate approach, which I
           happen to think is what should have been the approach
           all along, is to go after ANB.
                       VICE CHAIRMAN BONACA:  Well, the thing
           that troubles me about the whole thing is that all
           they can us is Reg Guide 1.174, and I wonder how many
           of the changes that will happen at South Texas will
           conflict with some of this GDCs.  I could bet you that
           there will be some conflicts.
                       And we have not gone back to what is the
           foundation of the original of the existing systems
           are, and so we are changing things here, and I think
           they can go only so far.
                       DR. POWERS:  Well, you have maintained
           function, and you have maintained all your Chapter
                       CHAIRMAN APOSTOLAKIS:  Did you guys raise
           the issue of containment earlier with South Texas?
                       DR. KRESS:  Yes, it came up.  Somebody
           mentioned it.
                       CHAIRMAN APOSTOLAKIS:  So it is not an
           issue anymore?
                       DR. KRESS:  Well, I think Sam Lee did.
                       CHAIRMAN APOSTOLAKIS:  So again what do we
           do here with this thing?  Should we let it rest until
           December and see what NEI comes up with?
                       DR. KRESS:  Yes, I don't think we are
           ready yet.
                       CHAIRMAN APOSTOLAKIS:  I really don't
           think we should be writing letters without hearing
           from the staff, and to ask them to come and talk about
           the GDCs, they will love us for it.
                       DR. SHACK:  Do you have another
           presentation on Option 2 scheduled?
                       CHAIRMAN APOSTOLAKIS:  Option 2?  Not in
           the near future.  Option 3 doesn't come to mind,
           except in 50.46.
                       DR. POWERS:  But Option 2 follows along
                       DR. SHACK:  Right.  It is a few months
                       CHAIRMAN APOSTOLAKIS:  But South Texas is
                       DR. POWERS:  But it is the generalization
           of the rule.
                       CHAIRMAN APOSTOLAKIS:  Oh, that is going
           to take --
                       DR. SORENSEN:  That originally was the
           quick fix.
                       CHAIRMAN APOSTOLAKIS:  Okay.  If we don't
           write the letter now, how do we make sure that Jack's
           work is documented and reviewable?
                       DR. SORENSEN:  There is a paper that I can
           put out as soon as --
                       CHAIRMAN APOSTOLAKIS:  A paper or report?
                       DR. SORENSEN:  It is 20 or 25 pages of
           this kind of discussion, one criterion at a time.
                       CHAIRMAN APOSTOLAKIS:  So why don't we get
           a report from you and maybe wait until NEI does
           something.  And if we find there another  opportunity
           where there is a reason to bring it up, then we bring
           it up.
                       DR. SHACK:  And Jack's conclusions aren't
           so different from what the NEI people said.
                       DR. POWERS:  And GDCs were not such a
                       CHAIRMAN APOSTOLAKIS:  Okay.  So let's
           recess -- oh, I'm sorry.
                       DR. KRESS:  I have another view of what
           the GDCs are before we leave them and while we are on
                       CHAIRMAN APOSTOLAKIS:  Okay.
                       DR. KRESS:  If I think about it, and if I
           had a system of this risk-based concept that I
           mentioned, and if I viewed defense in depth as being
           an allocation of the risk contribution through both
           the sequences and things like initiating events and
           mitigation, if I were reviewing defense in depth as an
           allocation among those things, then I would view the
           general design criterion as almost wholly defense in
           depth, because what it does is do that in a
           prescriptive constructionist way of doing it.
                       So I think if you had the proper
           definition of defense in depth, in terms of this
           allocation and in terms of related uncertainty that
           you would end up with something like -- if you carried
           it on down to lower and lower tiers, you would end up
           with something like the GDCs, and that's why I say
           that if they could start over from a top level
           concept, they might end up with a different type.
                       CHAIRMAN APOSTOLAKIS:  I think the Option
           3 guys have already done some of that.
                       DR. KRESS:  They may have.
                       CHAIRMAN APOSTOLAKIS:  But they didn't
           call them GDCs, but by the mere fact that they started
           by assigning values, upper bounds to intermediate
           events, that is a structural manifestation of defense
           in depth at that top level.  Okay.
                       Thank you very much, Jack.  It was very
           informative and we look forward to your report.
           And send it in draft form to all the members at some
                       DR. SORENSEN:  I had planned to do that,
                       CHAIRMAN APOSTOLAKIS:  And seek comments. 
           Okay.  And we will recess until 10 minutes past 5:00. 
                       (Whereupon, the meeting was recessed at
           4:58 p.m.)

Page Last Reviewed/Updated Monday, August 15, 2016