NRC: Reliability and Probabilistic Risk Assessment


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UNITED STATES OF AMERICA
NUCLEAR REGULATORY COMMISSION
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS
***
RELIABILITY AND PROBABILISTIC RISK ASSESSMENT

Nuclear Regulatory Commission
Room T-2B3
Two White Flint North
11545 Rockville Pike
Rockville, Maryland

Thursday, June 29, 2000

The committee met, pursuant to notice, at 8:30
a.m.
MEMBERS PRESENT:
GEORGE E. APOSTOLAKIS, Chairman
THOMAS S. KRESS, ACRS Member
JOHN D. SIEBER, ACRS Member
MARIO V. BONACA, ACRS Member
ROBERT E. UHRIG, ACRS Member
WILLIAM J. SHACK, ACRS Member
PARTICIPANTS:
Paul A. Boehnert, ACRS Staff
John T. Larkins, Executive Director, ACRS
Michael T. Markley, ACRS Staff
Howard J. Larson, ACRS/ACNW Staff
Noel F. Dudley, ACRS Staff
Cindi Carpenter, Office of Nuclear Reactor Regulation
Tom Bergman, Office of Nuclear Reactor Regulation
Mike Cheok, Office of Nuclear Reactor Regulation
Mohammed Shwaibi, Office of Nuclear Reactor Regulation
Tim Reed, Office of Nuclear Reactor Regulation
Joe Williams, Office of Nuclear Reactor Regulation
Mark Rubin, Office of Nuclear Reactor Regulation
Bob Christie, Performance Technology, Incorporated
Thomas King, Office of Nuclear Regulatory Research
Mary Drouin, Office of Nuclear Regulatory Research
John Lehner, Brookhaven National Laboratory
Trevor Pratt, Brookhaven National Laboratory
Allen Camp, Sandia National Laboratory
Steve Floyd, Nuclear Energy Institute
Adrian Heymer, Nuclear Energy Institute
Biff Bradley, Nuclear Energy Institute. C O N T E N T S
ATTACHMENT PAGE
Proposed Schedule 210
Introductory Statement 210
Petition for Rulemaking Combustible
Gas Control 211
PECO Energy Letter March 3, 2000 213
Risk-Informed 50.44 322
Memorandum to Ashok C. Thadani 344
Risk-Informed Part 50 Option 2 384
Risk-Informed Regulation 384

. P R O C E E D I N G S
[8:30 a.m.]
DR. APOSTOLAKIS: The meeting will now come to
order. This is the second day of the meeting of the
Advisory Committee on Reactor Safeguards, Subcommittee on
Reliability and Probabilistic Risk Assessment.
I am George Apostolakis, Chairman of the
subcommittee.
ACRS members in attendance are Mario Bonaca, Tom
Kress, William Shack, Jack Sieber, and Robert Uhrig.
The purpose of this meeting is to discuss the
status of risk-informed revisions to 10 CFR Part 50,
including proposed revision to 10 CFR 50.44 concerning
combustible gas control systems, issues in the Nuclear
Energy Institute letter dated January 19, 2000, option
three, and public comments related to the advanced notice of
proposed rulemaking on 10 CFR 50.69, and Appendix T, option
two.
The subcommittee will gather information, analyze
relevant issues and facts, and formulate proposed positions
and actions, as appropriate, for deliberation by the full
committee.
Michael T. Markley is the Cognizant ACRS Staff
Engineer for this meeting.
The rules for participation in today's meeting
have been announced as part of the notice of this meeting
previously published in the Federal Register on May 16,
2000.
A transcript of the meeting is being kept and will
be made available as stated in the Federal Register notice.
It is requested that speakers first identify themselves and
speak with sufficient clarity and volume so that they can be
readily heard.
We have received no written comments from members of the
public. However, Mr. Bob Christie, of Performance
Technology, Incorporated, has requested time to make a
presentation concerning proposed revision to 10 CFR 50.44.
I will remind the audience here that we wrote a
letter to the Chairman, dated October 12, 1999, on primarily
option two, but also option three.
We will now proceed with the meeting and I call
upon Ms. Cynthia Carpenter, NRR, to begin.
MS. CARPENTER: I thank you very much. Tom
Bergman, who is one of the co-leaders of the risk-informing
Part 50 effort, is going to start off and then we'll have
our speakers.
DR. APOSTOLAKIS: Good. Thanks.
MR. BERGMAN: Yes, just quickly. As you noted, we
are here to present on option two, which is risk-informing
the special treatment requirements. We gave the committee
three handouts this morning, one which is the slides. We
got a late comment letter, we've provided that to you, and
we gave you a copy of our user needs memo, in addition to
the material provided several weeks ago.
The presentation, we have two new presenters for
us. They've both been on the core team since its inception.
The first is Mohammed. He will be presenting the section on
the ANPR comments. Mohammed Shwaibi. He's been with the
agency for eight years, about both Region III and six years
here at headquarters of the eight.
In terms of option two, Mohammed, he led the
effort to develop the criteria and methodology for selecting
the rules in option two. He drafted the ANPR and he is
leading our evaluation of the comments we received.
Joe Williams will be presenting preliminary staff
views on treatment and he'll also cover the status and
schedule. He has been with the agency for ten years in the
Division of Licensing Project Management, mostly with Browns
Ferry, and 11 years in the industry.
In terms of option two, he is the PM for our pilot
program. He's our principal interface with the South Texas
exemption and he is leading the review of the NEI guideline
on categorization and treatment, as well as the peer
certification process.
And you all know Mike Cheok. He'll be addressing
the portions on categorization and PRA peer certification
process.
MR. SHWAIBI: Good morning. My name is Mohammed
Shwaibi, and, as Tom indicated, I'll be talking about the
ANPR comments today.
As you know, the ANPR was published on March 3.
There was a comment period of 75 days, which ended on May
17. In response to the ANPR, we received 11 comment
letters, which included over 200 comments. We received six
letters from licensees and industry groups, two letters from
law firms, one letter from a consulting firm, one letter
from a professional society, and one from a member of the
public.
The comments were divided into four major
categories. I'll be talking about categories that related
to the approach that we took. We described in the ANPR
comments that were related to the categorization process in
Appendix T, comments related to treatment, and comments
related to the pilot program that was presented in Appendix
T -- I'm sorry -- in the ANPR.
With regard to approach, we received comments that
were in general agreement with the list of rules that were
identified, with a proposal that the risk-informing of the
rules be taken in a phased approach.
The proposal was to risk-inform the rules that
were special treatment type rules, such as 50.49 EQ rules,
seismic qualification, and those types of rules, and the
administrative rules, such as reporting, documentation, be
done in a later phase, and to break up the tech spec rule in
Appendix R and fire protection as a separate and parallel
effort.
We were told to be performance-based in the
approach that we take, make sure that the resulting rules
are optional and allow for selective implementation for both
the resulting rules and systems at the plant.
We were told that the resulting rules should
provide for limited NRC prior review and approval and that
we should apply the backfit rule to option two.
DR. APOSTOLAKIS: Now, when you say that you
received these comments, you have here 11 different letters.
MR. SHWAIBI: Yes.
DR. APOSTOLAKIS: Were they unanimous in these
recommendations?
MR. SHWAIBI: I'm sorry?
DR. APOSTOLAKIS: Were they unanimous in the
recommendations? I mean, all 11 asked that the thing be
selective, the subject of selective implementation?
MR. SHWAIBI: Pretty much, yes. With regard to
selective implementation, they were pretty unanimous.
MR. BERGMAN: For those that commented on it, to
qualify that.
MR. SHWAIBI: Yes.
MR. BERGMAN: Where there was a comment on
selective implementation, most of the commenters didn't
address all the questions in the ANPR. But for those that
did, they were supportive of selective implementation.
DR. UHRIG: By selective implementation, do you
mean voluntary? That is, the utility has the option, or is
this the NRC's selectivity?
MR. SHWAIBI: No. It's the utility would have the
option.
DR. UHRIG: Have the option.
MR. SHWAIBI: Yes.
DR. UHRIG: Then why would you apply the backfit
rule?
MR. SHWAIBI: Well, one of the commenters did
indicate that we ought to apply the backfit rule so that the
Commission can have a full understanding of what we're
requiring in the proposed rule or in the final rule. They
said that we should not bypass the backfit rule just because
it's voluntary.
DR. UHRIG: Is that standard procedure? I thought
it was not.
MR. SHWAIBI: I don't believe.
MR. BERGMAN: We have not decided how to address
each individual comment. We'll be doing that as part of our
August paper.
DR. UHRIG: My comment was intended -- is this the
procedure within NRC? I thought if a rule was voluntary,
you did not apply the backfit rule.
MR. BERGMAN: That is true. That is how we've
done it in the past and I believe that's what was said.
DR. UHRIG: Then why would this be different?
MR. BERGMAN: We haven't decided how we will
address it. We have a commenter who has proposed that we
apply the backfit rule. Whether or not we'll accept that
comment we have not decided.
MR. SHWAIBI: This is just a summary of the
comments that were provided. We don't have positions yet on
them.
DR. KRESS: By selective implementation, I thought
you meant they could choose which of the rules they want to
go by and which ones they didn't.
MR. SHWAIBI: That's correct. The comments were
provided on selective implementation with regard to the
rules and selective implementation with regard to systems at
the plants. That is, a licensee could select which rules
they want to implement and then they could also select which
systems at the plant they chose to apply the risk-informed
approach to.
Moving on to the categorization of Appendix T. We
received comments that the Appendix T that was in ANPR was
unduly detailed, prescriptive and burdensome.
DR. APOSTOLAKIS: Can you give us an example of
what people felt was burdensome?
MR. CHEOK: I think one quick example of that,
George, is that we had asked for all SSCs to be identified
and what the current requirements for those SSCs are, and I
think that one of the comments was that's asking too much
for the SSCs, since there are thousands of them.
DR. APOSTOLAKIS: But didn't South Texas do this?
MR. CHEOK: In a sense, they did, yes.
DR. APOSTOLAKIS: Yes.
MR. CHEOK: I think when we wrote Appendix T, the
idea was that there was going to be minimal staff review and
approval. I think industry may be backing up a little bit
instead of maybe there should be some kind of a submittal
and, you know, when we make the submittal, we would like the
rules to be less prescriptive, because then whenever they
want to change the process, it's not allowed because it's
not in the rules or the regulations.
DR. APOSTOLAKIS: Is this related to a
recommendation I saw somewhere that Appendix T be eliminated
and replaced by a regulatory guide?
MR. CHEOK: That's related to that recommendation,
yes.
DR. APOSTOLAKIS: And how does the staff feel
about this?
MR. CHEOK: We are open to that recommendation.
The material in Appendix T can either reside there or it can
reside in another document, like a reg guide or an industry
document, which the staff endorses.
DR. APOSTOLAKIS: So this is still to be decided.
MR. CHEOK: It's still be decided.
DR. APOSTOLAKIS: And the unduly detailed, can you
give an example of a detail that shouldn't be there?
MR. SHWAIBI: I could provide you some examples.
We have a list of examples.
DR. SHACK: Just coming back, while you're at it,
I thought there was some discussion whether, if you put it
in a reg guide, you had to do more review and approval,
whereas if it was in the rule, you had less review and
approval, and that was the justification for making it part
of the rule in the first place.
MR. CHEOK: That's correct. And like I said, I
think industry is backing off a little bit and they feel
that they would like the flexibility.
DR. SHACK: Okay. So they have the flexibility.
MR. CHEOK: And perhaps maybe make a limited form
of review, what they call a template type review.
DR. APOSTOLAKIS: A what kind of review?
MR. CHEOK: A template; in other words, an agreed
upon five-pager or something.
DR. APOSTOLAKIS: Okay.
MR. BERGMAN: The unduly detailed example would be
the precise makeup of the IDP. It was spelled out in the
draft Appendix T included in the ANPR.
DR. APOSTOLAKIS: I'm really curious myself about
the IDP, because we are performing unduly detailed reviews
of the PRA part and then we are turning over the results to
the IDP, and they are pretty much free to do whatever they
please.
I think we are spending our resources reviewing
something that can't be reviewed because it has some
quantitative elements in it, whereas the IDP is just the
deliberative process.
So at some point in the future, we really have to
think about it very hard. Maybe there ought to be some
general guidelines regarding the conduct of the
deliberation, because we worry about little things here and
there, the significance of other -- sensitivity of
importance measures of various things, and then we're taking
the results and saying now you guys do what you like with
those.
Well, it's not like that, but.
MR. CHEOK: I think the staff is working with the
industry on the guidance document and how the IDP should
deliberate, and hopefully we'll come up with something
that's acceptable to everybody.
MR. SHWAIBI: I think the comments were mostly to
take the details and put them in the guidance document.
They want to be able to -- some of the things that were
pointed out were as advances in technology occur, we want to
be able to take advantage of those without having to go back
to rulemaking.
And if you lock them in in Appendix T or in the
rule, that would make it hard to do. You'd have to go
through rulemaking, and those were some of the comments on
the level of detail that needs to be included in the
appendix and in the rule versus the level of detail that
could be included in a guidance document or a reg guide.
DR. APOSTOLAKIS: I don't understand the second
bullet. What is the consensus PRA standard, the ASME and
the ANS?
MR. SHWAIBI: In the proposed --
DR. APOSTOLAKIS: Can you move up the microphone a
little bit?
MR. SHWAIBI: I'm sorry.
DR. APOSTOLAKIS: Good.
MR. SHWAIBI: In the proposed Appendix T, I
believe it was identified that the PRAs would have to meet
the consensus standard, ASME, ANS, whichever one would be
available at the time. It was expected, I guess, that they
would be available at the time.
DR. APOSTOLAKIS: I wonder the people who wrote
this had seen the standard.
MR. CHEOK: The people who wrote this, and you're
looking at him, has not seen the standard at the time.
DR. APOSTOLAKIS: Wait a minute. You are not the
public.
MR. CHEOK: You mean the comments.
DR. APOSTOLAKIS: Yes.
MR. CHEOK: All right.
DR. APOSTOLAKIS: You're not public. I mean, it's
such a high level document, that I don't understand what it
means, that it should not be accepted as the only method.
It's not even a method.
MR. CHEOK: I think the intent of the thing is
maybe we should look at other avenues; for example, the PRA
certification that's being forwarded to the staff to look at
and that the ASME standards should not be the only way.
That is a public comment that we have to address.
DR. APOSTOLAKIS: It's really such a high level
document, that I don't know that it cannot be the only
acceptable method. Basically, it tells you to do fault
trees and event trees.
Why is it important to minimize the levels of the
risk significance?
MR. SHWAIBI: I'll give you what was provided in
the comments. It was suggested that with the different
levels of risk significance, you would need to come up with
different treatment requirements for those levels and that
would just be too complex.
DR. APOSTOLAKIS: South Texas didn't.
Essentially, they have four categories or something.
MR. WILLIAMS: South Texas has four levels of risk
significance, but really only two types of treatment.
DR. APOSTOLAKIS: That's right.
MR. WILLIAMS: Because the high safety significant
and medium safety significant are treated essentially the
same.
DR. APOSTOLAKIS: Exactly. So in essence, they
have two categories.
MR. WILLIAMS: Yes.
DR. APOSTOLAKIS: So I don't understand that
comment either, or there is a concern that there might be
different --
MR. SHWAIBI: Different levels of treatment.
MR. RUBIN: I'm Mark Rubin, from the PRA Branch.
Just one quick data point. South Texas, originally, in the
GQA submittal, you may remember, had an intermediate
category. So perhaps the public comment was reflecting
that. Allowing too many categories gets too complex, and I
think South Texas concluded that and they went back to a
single cut point.
DR. APOSTOLAKIS: And what's a functional
categorization?
MR. SHWAIBI: Yes. In the ANPR, the way that
categorization was discussed was to bin structures, systems
or components, and that comment was saying that we ought to
look at the functions that these components will be
providing and those functions.
So in other words, you're dividing -- you're
taking the different functions of a component and binning
them into the different bins. You will be taking the
different functions that a component will be providing.
Instead of binning all of the functions of the
same component in one class, in one safety class or one risk
class, you could take the different functions of that
component and bin those functions into the different
classes.
So a component could have functions in different
classes.
DR. APOSTOLAKIS: And then you would go with the
most stringent category or you would have it targeted?
MR. BERGMAN: We'd target by function.
MR. SHWAIBI: You will address the functions or
the attributes that give you the function that ended up in
the different bins.
DR. APOSTOLAKIS: I wonder how you would do that?
MR. BERGMAN: George, I think this is a lesson
learned from the maintenance rule. The maintenance rule was
written on an SSC basis, as well, but most licensees
implemented it with a function-based approach, which, after
we observed it, we concluded it was a very good way to
tackle the problem.
In South Texas, in a meeting a couple months ago,
they pointed out that they've looked at something like
22,000 components, but those components only fill 500
functions.
So by taking the function-based approach, it does
appear to simplify the problem somewhat. They're just
saying consider allowing us that flexibility to tackle the
problem using either approach, component-based or
function-based.
DR. APOSTOLAKIS: I guess it's not clear to me. I
thought it would make the process more complicated. So
you're not taking -- the way you described it, Mohammed,
you're taking one component that may have three functions.
MR. SHWAIBI: That's correct.
DR. APOSTOLAKIS: So you categorize -- now,
instead of categorizing one component, now you have three
functions to categorize.
MR. SHWAIBI: That's correct.
DR. APOSTOLAKIS: So that makes it more complex.
MR. SHWAIBI: That's correct.
DR. APOSTOLAKIS: We were just told that it's
actually simpler.
MR. BERGMAN: Because there only may be, take the
example, 500 functions. You may have 50 components, all
fulfill the same function.
DR. APOSTOLAKIS: I see.
MR. BERGMAN: So especially when you get into the
monitoring aspects, you're monitoring functions, which is
typically what you look at anyway, are you injecting enough
water, are you maintaining the bus voltage, and when you
fail to meet that condition, then you track down to figure
out what's causing the inability to fulfill the function.
But when you look at your plan, it's easier to
look at it from a functional perspective.
DR. APOSTOLAKIS: But eventually you would have to
go to the hardware.
MR. BERGMAN: You always have to end up going to
the hardware.
DR. APOSTOLAKIS: Because there may be an
intermediate step that makes it a bit easier.
MR. BERGMAN: Right. As long as stuff works, it's
easier from a function-based. When you have a lot of stuff
breaking, you're ultimately back at components anyway.
MR. SHWAIBI: I think if you go back to our
four-box diagram, one of the comments said that if you have
a component that ends up in box one or RISC-1, ends up as a
RISC-1 category, yet it does not need to be environmentally
qualified because of the functions that it provides, it
should not have to meet the 50.49 environmental
qualification criteria.
You could take the environmental qualification
parts, and maybe that is lower safety significant.
DR. APOSTOLAKIS: But, still, it's new to me, so
bear with me for a minute.
I'm categorizing the function of a particular
component for a function that is needed for the safety of
the plant.
MR. BERGMAN: It's kind of both. I think the
example that Mohammed brought up is very good. You're
looking at the functions and you'll have RISC-1 functions
and you say which components fulfill that function and the
function, though, may only be applicable for, say, seismic
reasons, but not the rest of EQ.
So right now, if you do a component, if it has any
-- if it's safety-related for any reason and it's
safety-significant for any one reason, the entire SSC and
all the functions its performed remain subject to all the
special treatment rules.
If you go on a function-based approach, you would
only need to apply those special treatment rules for those
functions that are both safety-related and
safety-significant.
So it does allow a little bit more flexibility.
DR. APOSTOLAKIS: There could be a downside,
though. I remember a complaint from South Texas was that if
a function is in the box RISC-1, then automatically all the
components supporting that function were RISC-1. Do we have
the same problem here?
MR. BERGMAN: Oh, you definitely could. There's a
balancing between -- it makes your approach to the component
much more complicated and I think South Texas has concluded
if it's high for any reason, just throw the whole thing in
high and just keep dealing with it the way you deal with it
today rather than trying to pare away at it.
So it's a comment we've got. Like you said, how
it plays out, we don't know. They're just asking for the
flexibility. I don't think even utilities will know till
they actually get implementation which approach is
necessarily better.
MR. REED: Utilities still may want to do it on
specific circumstances. The component that comes to mind
for the examples, for me anyway, is the RHR pump. For ECCS,
it may come out, for that low head pump, maybe come out low
safety significant, let's say, but for mid-loop, it may come
out mid or high or for achieving maintain safe shutdown
condition, it may come out high or medium.
You would want to treat it appropriately for
mid-loop or achieving maintain safe shutdown condition,
those functions as high or medium.
ECCS now, which is a lot of what the best
treatments are focused on on that particular component,
while they're not doing anything for you, you know what I'm
saying. So there may be a few where they want to split it
apart, but like Tom said, it does get complex.
It simplifies the categorization process, because
you're categorizing, say, 500 things and then you're mapping
components into that, if you will, but in the end, when you
come down to the component and you've got this thing in
different boxes, in a sense, based on its functions, that
gets complex and I think that's where South Texas said we're
simplifying this.
So if it's got anything that's high, it's high for
everything.
DR. APOSTOLAKIS: The example you just gave
considered two different modes of operation.
MR. REED: Yes.
DR. APOSTOLAKIS: In which case, the PRA is
different, the measures are different, everything is
different. That's not what I understood by function or
categorization. I understood that for the same mode, the
same importance measures and so on, instead of going
directly to a component and asking what is its role, in
general, you are looking at specific functions that it
supports, and for some of these functions, it may be RISC-1
and for others it can be something else.
But for the same mode, if you change the mode of
operation, then you're changing the importance measure. So
it doesn't surprise me that --
MR. REED: Yes. Actually, change mode and
actually change internal and external events, too. I did
the whole thing there. I think we've got to consider the
whole gamut, actually. I don't know.
DR. APOSTOLAKIS: They are talking about, in one
mode, having different functions and categorizing those. Is
that the intent of this bullet?
MR. SHWAIBI: I'm not clear if the comment is
actually talking about one mode. I think the comment was to
allow the flexibility to do this. It's not specific as to
for one mode, you would need to do it. But I would imagine
that if you were doing --
DR. APOSTOLAKIS: Now, you changed the mode of
projection. Why?
MR. SHWAIBI: It just went off. I guess it was a
screen saver. It went off.
DR. APOSTOLAKIS: Okay. That's better. Why does
it say random access? Shouldn't it be alliatory access?
Okay, Mohammed, go on. You're kind of slow today.
MR. SHWAIBI: I guess move on to the last bullet,
then.
DR. APOSTOLAKIS: Yes.
MR. SHWAIBI: That we need to address the use of
results from PRAs or tools with different levels of
conservatism or uncertainty.
DR. APOSTOLAKIS: That's a mystery to me what it
means. Can you elaborate?
MR. SHWAIBI: Yes. The intent of the comment here
is that we have different tools that we're using for
categorizing. For shutdown, we have certain tools, for
seismic, for fire, and for internal events, and we don't
want the conservatisms and uncertainties in one tool to mask
significance that would come out from another tool.
We don't want, for example, our shutdown tool to
drive a component into the low bin when it should be high
for the internal event scenarios.
DR. APOSTOLAKIS: So how would you handle this?
MR. SHWAIBI: I think that's already --
DR. APOSTOLAKIS: It sounds like a research
project, to me.
MR. CHEOK: I think in Appendix T, what we say is
that if you do have a PRA model for fires, for, let's say,
low power and shutdown, that you take the importance
measures and you treat them both cumulatively and
individually, and you need to look at the results, both sets
of results, and categorize your SSCs based on both sets, not
just the cumulative results.
DR. APOSTOLAKIS: By cumulative, you mean PRA as
one.
MR. CHEOK: Consider all the cut sets into one.
DR. APOSTOLAKIS: And then you separate out, say,
the fire and see what happens.
MR. CHEOK: Right, and low power and shutdown,
because they do tend to be maybe more conservative and they
might skew the results.
DR. APOSTOLAKIS: Okay, sir.
MR. SHWAIBI: Moving on to treatment. We have
comments that suggested that any additional treatment for
safety significant attributes should be determined by the
licensees and that they should rely on existing licensee
programs. Those would be in the RISC-1, RISC-2 boxes.
DR. APOSTOLAKIS: What happened then to the declaration that
risk-informing the results may, in fact, lead to additional
requirements?
MR. SHWAIBI: Again, this was the comment. We're
still addressing it. We don't have a response to that yet.
DR. APOSTOLAKIS: I think Mr. Riccio would like
this. Okay.
MR. SHWAIBI: For LSS SSCs, commercial programs
provide sufficient treatment, was the comment on those.
DR. APOSTOLAKIS: Somebody asked the question on
Tuesday, which I will ask you now.
MR. SHWAIBI: Yes.
DR. APOSTOLAKIS: What is a commercial program?
MR. SHWAIBI: We're in the process of trying to
learn what that is, trying to understand what it is.
MR. BERGMAN: We'll talk about that a little bit
later.
MR. SHWAIBI: The rulemaking should eliminate
existing commitments for LSS SSCs, was another set of
comments. Any existing commitments would be eliminated.
DR. APOSTOLAKIS: Now, a matter of terminology
again. Low safety significance is what used to be called
low risk significance.
MR. SHWAIBI: Low safety significant SSCs, here,
what we're basically talking about is the RISC-3 box. Any
commitment --
DR. APOSTOLAKIS: I understand that. I mean the
terminology. Safety significance is the former risk
significance.
MR. CHEOK: Yes.
DR. APOSTOLAKIS: Yes. And why the change in
terminology?
MR. CHEOK: I think for a while now we have been
using low safety significance to be consistent throughout
the whole agency. I think we have been using LSS and HHS
for the last three years or so, since we were implementing
the maintenance rule.
DR. APOSTOLAKIS: So something can be
safety-related and of low safety significance.
MR. CHEOK: Right.
MR. SHWAIBI: And, finally, that the risk-informed
-- a risk-informed change process should be included in the
new rule. This is where we recognize 50.59 may not be
sufficient and we need to include something other than
50.59.
DR. APOSTOLAKIS: Change process?
MR. SHWAIBI: Change control process, yes.
Finally, on pilot programs, we received comments
that the final rule should not be backfit on pilot plants
that have reviewed and accepted processes for categorization
and treatment.
In addition, we received comments that since STP
has already demonstrated that they can categorize and
provide treatment for different types of components, that
there is no need for other pilot plants to do the same.
This is where, in the ANPR, it was suggested that pilot
plants would need to include passive components, active
components, mechanical, electrical and all types of
components, and the commenter was saying that there is
really no need to do that, since South Texas would have
demonstrated that.
If there are no comments, I'll turn it over to Joe
Williams. I think he's next.
MR. WILLIAMS: I'm Joe Williams. I'm the project
manager for the review of the NEI guideline documents.
What we have here, first of all, is we have three
guidance documents. Two of them are actually part of what
will be a single document.
First of all, NEI submitted NEI-0002 in April of
this year. That provides their peer certification process.
They have also provided their categorization guidance for
option two application. That was submitted in March of this
year. Then in June, they just submitted their draft
treatment guideline.
We'll start discussing the review of NEI-0002.
We're working with the Office of Nuclear Regulatory Research
in the review of this document. We have an overall outline
that's presented the next couple of slides. Mike will be
speaking to most of these points.
I just want to point out that our intent is to
provide comments to NEI. We have talked to them a couple of
times at public meetings about the categorization, the
treatment and the peer review.
We're going to be providing formal comments to NEI
over the next couple of months and then we'll be working
with them to develop a final document that hopefully will be
endorsed in the regulatory guidance that will go forward
with the proposed rule.
Mike will now talk about the particulars of the
review of the NEI-0002.
MR. CHEOK: This NEI-0002 is basically the
industry peer review certification process. This is the
process that was, I guess, adopted from the BWR Owner's
Group process that was presented to the committee probably
six months ago.
To review this document, we came up with a task
plan and like Joe was saying earlier, this is going to be an
Office of Research and NRR effort.
The task plan has four tasks in it. Task one
basically calls for us to review the process itself, the
overall process, to see if it meets the general staff
expectations of what we think a peer review should look
like.
We also would like to look at the QA requirements
that are being put on the PRA. In Reg Guide 1.174, we did
say that parts of Appendix B should apply to the PRA, since
it's used to change the licensing basis. We would like to
see those parts of Appendix B being implemented.
In task two, this is the task that our Office of
Research, I guess led by Mary Drouin, is going to be looking
at. This task basically looks at the technical elements of
the peer review process.
Again, we are writing a SECY paper, due to the
Commission probably the middle of next month, that outlines
our high level expectations of what we would like to see in
the PRA.
So the Office of Research is going to use these
high level expectations as a guidance to look at the peer
review certification process to see if they meet this
guidance criterion.
The next thing they're going to do is they're
going to look at the sub-tier criteria that's provided by
NEI-0002. We should note here that in submitting the
document, NEI has asked that we do not look at sub-tier
criteria -- I mean, do not review the sub-tier criteria.
They would just provide it for information.
The staff had come to the conclusion that we do
need to look at the sub-tier criteria because this is the
basis for which the peer reviewers are going to make the
decisions whether something is graded with one, two, three
or four.
So we have written a letter back to NEI to state
that, yes, we will look at your certification process, but
we will have to look at them in concert with the sub-tier
criteria.
So part of task two here is for the Office of
Research to look at this sub-tier criteria and, in a sense,
compare it to existing and available documents, the ASME
standards being one of them, to see how consistent they are.
That's the first task in this sub-task.
And then if there are inconsistencies, determine
if these inconsistencies will affect applications in option
two.
Task three is then actually to look at what we
actually want to do in option two. Remember, NEI has asked
us to review the certification process in conjunction, in
light of applications to option two.
So what task three does is that we need to look at
what the requirements of option two are. In other words,
what's the role of PRA in option two and how are we going to
use the results of a PRA in option two; how are things like
defense-in-depth, safety margins, and the other expert panel
type issues going to affect the results of the PRA.
DR. SHACK: Mike, I as recall, I didn't think you
assigned an overall grade to a PRA. Wasn't it sort of
graded on an element by element basis? Do we take an
average or something?
MR. CHEOK: No. You are actually correct. We do
give a grade to the elements themselves and NEI-0002 is very
clear in saying that we do not assign an overall grade to a
PRA.
DR. SHACK: Then what does task two mean then?
Somehow it sounds as though there's something like the grade
three PRA, grade three PRA is the overall beast.
MR. CHEOK: I think I'll go to that a little bit.
Basically, what happens is NEI has asked us to look at this
certification process with respect to option two and since
they have four grades, the grade that corresponds to what
the PRA should be to be good enough for option two is the
grade three PRA.
So basically you're looking at the sub-tier
criteria for grade three to see if these sub-tier criteria
are what we think is needed to be applied for each element
for option two.
DR. SHACK: Suppose he comes out with grade three
in X attributes and grade two in Z attributes.
MR. CHEOK: And I think we will discuss this in
the next slide, but basically what happens is -- one of our
comments to them is, look, you have to come up with a
certain level of conformance in each element and then if you
do not conform, we would like to know why you don't conform
and document that, so that your expert panel will know why
you don't conform and how you can get around this, what we
call the tradeoffs to apply to option two.
But this thing has to be documented well enough
for your expert panel to know and for the staff reviewer to
know that you have used these tradeoffs correctly.
In a sense, I'm not -- I hear this committee
discussing the grading levels yesterday for the ASME
standards, and the more I listen to the discussion, the more
I'm thinking the ASME is talking themselves out of having
different grades, because, in a sense, they are defining a
standard for grade four, for example.
And you come in and say, hey, look, for this
application, I may not meet the standards, but I do not meet
them because, here's my reasons, and there could be more
bullets for grade one and maybe less bullets for grade two.
But I think when you apply something, you need to
know those bullets anyway and you need to know how to get
around those bullets or those bullets have to be fixed in an
update of the PRA.
So in essence, you're really comparing yourself to
a standard, which is the grade four standard, and for each
application, you need to know how you -- the tradeoffs are
probably different for each application.
So in that sense, I'm not sure.
DR. SHACK: It's a useful tool for
self-assessment.
MR. CHEOK: That's right, that's right.
DR. SHACK: I can see where my PRA has had
shortcomings. It's not category one, two or three or grade
--
DR. APOSTOLAKIS: Use your mic.
DR. SHACK: He's going to have to come in, as you
say, and defend it.
MR. CHEOK: Right.
DR. SHACK: He'd be better off to go to grade four
or category three and be done with it.
MR. CHEOK: Right. In essence, a grade two is I'm
conforming to the standards, but to a less extent than grade
three is. And how I don't conform to it, I have to document
anyway, because I need to know why it doesn't conform, not
just that it's a grade two.
A grade two by itself doesn't mean anything to me
and a grade three doesn't mean anything to me.
I like to know why it's a grade three. So in that
sense, putting the different grades out there doesn't really
make that much sense.
DR. SHACK: Except for a self-assessment tool or
to tell you how to fix it up.
MR. CHEOK: So basically, here in task three, like
we were talking earlier, we would like to understand why
something is not up to par and if there are any compensatory
measures or tradeoffs that can be done; for example,
sensitivity studies or more defense-in-depth to get around
this one element that's not up to par, so to speak.
And the last task, we are trying to define what
elements of the peer review process are important enough
that it needs to be submitted to the staff and what elements
are important enough to be kept on-site for staff
inspection, so to assure us that this process has been
carried out correctly.
Here, we met with NEI on Tuesday, two days ago,
and our comments on NEI-0002, these are the high level
initial comments, basically are summarized in these four
bullets.
We said that we need sub-tier criteria to review
the certification document.
MR. WILLIAMS: If I may. One thing I want to
point out, too. It's not just that the sub-tier criteria
are integral, but also that we received only the BWR
sub-tier criteria. We also need the sub-tier criteria for
the pressurized water reactors, as well.
MR. CHEOK: We said that it's important for this
process to document all the findings very well. It's in
these findings that make the peer review process itself
useful.
For example, I'll give an example. For grade
three, there's a lot of "should's" in there. The "shalls"
go in grade four, and the "mays" go in grade two.
If you look at the definition of a "should," it is
you shall either have met the requirements or you have good
documented reasons why you didn't meet the requirements.
I think that the licensee, PRA analysts, the
expert panel, as well as the staff, need to know what
"should" means in each of these cases. Is it because they
met the element or is it because they had something that --
some documentation that says they don't have to meet this
element.
This documentation or justification might actually
affect the application and if that's the case, I think we
should have it ready for the expert panel to review and act
on.
Keep in mind that the certification process could
have been done two years ago with no application in mind.
So I think good documentation of this process is essential.
The third bullet here is how applicable are
previous peer reviews. In other words, the majority of BWRs
have already been peer-reviewed. A lot of the PWRs are
being reviewed currently.
How do we apply the results of past peer reviews?
I mean, the sub-tier criteria were not put down on paper
until probably recently. What do we do with cases like
that? What happens if the staff finds some discrepancies
and would like to add the staff guidance into the guidance
document? What do you do with plants that have already been
certified?
So that's a topic that we need to discuss with
industry.
Independent decision-making panel, again, I think
Dr. Apostolakis pointed this out earlier, we are saying that
perhaps the PRA doesn't have to be as good as our standards.
Our expert panel can take care of this.
I think we need to have good guidance to the
expert panel as to how they can take care of this.
Categorization. NEI submitted this document to us
in March and in the document they talked about PRA scope and
quality. It was at that meeting that actually it was
suggested that they submit to us NEI-0002 to address the
quality issue.
As far as the scope issue is concerned, they are
proposing that an external events PRA and a low power
shutdown PRA is not necessary for this process, and in
Appendix T, the staff actually basically said the same
thing.
NEI has proposed processes where you can use 91-06
criteria that's for risk management and shutdown
configurations and how you can use analyses and the seismic
margin analyses in light of PRA and how we can categorize
components using those kinds of analyses.
The staff is looking at those proposals and,
again, I think it comes down to the role of the expert
panel.
It's my personal feeling that if you are going to
not do a PRA, you should be a little bit more conservative
in your assessment of categories.
You should encourage the use of PRAs and they
should be able to tell you the more correct results.
So, again, this comes to how we define the role of
the expert panel.
DR. APOSTOLAKIS: Mike, as I recall, the South
Texas project categorized something like 21,000 SSCs,
roughly. And a typical number of SSCs that appear in a good
PRA is on the order of maybe 1,200. That's the number.
MR. CHEOK: The number of events, the basic events
in a database normally is 1,200, 2,000, something like that.
That could be less SSCs even, because --
DR. APOSTOLAKIS: Less SSCs.
MR. CHEOK: Yes.
DR. APOSTOLAKIS: The point is that it's 20,000
versus 1,200, 1,500, 1,000, that kind of number.
MR. CHEOK: Right.
DR. APOSTOLAKIS: Which means that you had almost
20,000 SSCs that were categorized without the PRA.
MR. CHEOK: Correct.
DR. APOSTOLAKIS: Are you familiar with the
process that they followed to do this? We had a short
presentation here once.
MR. CHEOK: I'm not totally familiar with what
South Texas did, but what Appendix T calls for basically is
to first map the SSCs on to the PRA, if you can; in other
words, to implicitly model SSCs.
So instead of the 2,000, you might actually have
6,000, the piping, the instrumentation that's dependent on
the operators, the tanks.
DR. APOSTOLAKIS: Yes. So this is a variation, if
you will, of the risk-informed ISI approach, the
Westinghouse surrogate component.
MR. CHEOK: In a sense it is, yes.
MR. WILLIAMS: If I may, with regard to the South
Texas, I know that part of that process is that they have
several critical questions that they ask about these non-PRA
components, if you will, such as whether or not they're
involved in the emergency operating procedures or not.
They assign a numerical rank from essentially zero
to five rank.
DR. APOSTOLAKIS: Yes.
MR. WILLIAMS: According to some criteria, and
then they have some weighting. Then they have rules that
they've applied that according to the sum of all those ranks
for the individual questions and the weights, that they then
will bin those SSCs according to where they fall out of that
numerical system.
DR. APOSTOLAKIS: So I think -- I mean, I fully
agree with you that this sounds, and it is, a structured
process, but I'm not sure that, as a community, we have
really understood what the process is and what it means to
do certain things.
For example, do these different constructed scales
they use, do they represent independent attributes, mutually
exclusive attributes, do they have to be independent, is
there a risk of double counting perhaps.
You know, all these things -- we're getting now
into the structure of deliberative processes, which is not a
new field for some community, but that community is not part
of our community.
So I think since they are making these important
decisions, I think we should look at this process a little
bit more carefully. These may turn out to be great, that's
fine, I'm not saying there are problems with it. In fact, I
was very pleasantly surprised when I heard South Texas
presented and showing that they actually tried very hard to
put some structure into the process.
MR. CHEOK: We do have some experience with South
Texas and we do have experience with ISI and IST, with the
pilots in there. So we do have some kind of experience with
how expert panels do work, but I think we still need to nail
down exactly how the process should go.
DR. APOSTOLAKIS: Do you have any document that
describes what was actually done? Because I haven't really
seen it. Besides the presentation, I'm not familiar that we
have anything else.
MR. WILLIAMS: For South Texas?
DR. APOSTOLAKIS: Yes, or anybody who has used --
MR. WILLIAMS: Certainly we have the submittals
that South Texas has made to date.
DR. APOSTOLAKIS: It's just the results of the
process itself.
MR. WILLIAMS: It's the process itself. They
described the process in some --
DR. APOSTOLAKIS: Can you give an example or two?
MR. WILLIAMS: I believe so, yes, because we have
copies of some of the risk significance basis determination
documents.
DR. APOSTOLAKIS: Is that a huge document?
MR. WILLIAMS: The risk significance determination
document, that's pretty large. The documents involving the
description of the processes, those are manageable.
DR. APOSTOLAKIS: May you can coordinate it with
Mr. Markley here.
MR. WILLIAMS: We can take care of that.
DR. APOSTOLAKIS: And see if part-time people can
review it in a reasonable amount of time.
MR. CHEOK: I'll keep going through this bullets
quickly. The second bullet basically says the role of
importance analysis can be used in sensitivity studies to
bound an increase in risk, or do we just depend on the
importance matrix, such as Fussel-Veseley and RAW.
The next bullet there is, again, the expert panel,
what role it plays, and we have discussed that quite a bit
already. The fourth bullet there is how we treat low safety
significant safety-related components, and I think Joe will
talk about that in later slides.
The last bullet there is what role should
monitoring and feedback play in this whole process, how does
this affect the PRA updates and how does this affect the
whole process in general.
DR. APOSTOLAKIS: Now, you know that we had this
presentation from Palisades on top event prevention
methodology. Is that left out because the authors of the
NEI-0002 were not aware of it, as most people are not, or
because they decided they would go with Fussel-Veseley and
RAW?
MR. CHEOK: I think the Fussel-Veseley and RAW is
something that's known to everybody. Everyone has the
capability of doing it. So that's the way that NEI chose to
go.
The top event prevention is another acceptable
method to do this. I think they have at least one licensee,
maybe two or three others might follow, but on a generic
sense, they do not have enough -- I guess we can call it
support for that methodology.
DR. APOSTOLAKIS: But, again, though, they don't
have enough support because people have studied it and they
decided not to support it or because it's just brand new and
they are not really familiar with it?
MR. CHEOK: I believe they are probably somewhat
familiar with it. They just chose to go with the method
that they already know how to do and they think will work.
DR. APOSTOLAKIS: Do they allow other methods to
be used?
MR. CHEOK: I think the documentation is such that
they would be flexible to allow any other methodology, and
the staff, in fact, say you can actually submit a top event
prevention, if you like. There's nothing to stop them from
doing that. We will just have to review it on its own
basis.
DR. APOSTOLAKIS: Well, at some point, though, we
have to understand what the differences are. Are we getting
more or less or are you doing one methodology versus the
other?
MR. CHEOK: We have an e-mail, I guess, we have
communicated with Palisades on what they should be doing
about the top event prevention methodology. They want to
apply it to IST.
We haven't gotten back to them yet, but basically
what we're going to tell them is that, sure, go ahead and
submit it, we would like to find out more about it, and find
out how applicable it is to option two and the rest of the
stuff we're doing.
DR. APOSTOLAKIS: Okay. So you are in the process
then of examining further that methodology.
MR. CHEOK: That's correct.
DR. APOSTOLAKIS: Okay.
MR. WILLIAMS: We will now talk about some of the
feedback we've given to the industry regarding treatment
guidelines. Most of this discussion was provided to NEI and
other industry stakeholders on Tuesday.
The first bullet deals with the definition of
commercial practices. One of the predominant issues here is
that commercial practices covers a very wide range of
activities.
Consider, for example, the distinction between a
Rolls Royce and Yugo. Both of those are commercial
vehicles. They're presumably for the same end, but clearly
much different in their application.
The staff is interested in basically defining the
set of commercial practices that provides an adequate
assurance of functionality, both in the context of the
preservation of the design basis for the components that are
categorized in the RISC-3 area, and also when those
commercial practices are applied for the, for lack of a
better term, severe accident attributes in the RISC-1 and 2
areas.
The NEI document, NEI-0002, has provided a useful
outline of how they propose to proceed in this area, but the
staff is going to need additional details before we can
complete our review.
The next bullet deals with the preservation of the
design basis. Fundamentally, that's, under option two, the
existing deterministic design basis is supposed to be
preserved. It cannot be changed by the rule itself. If the
licensee chooses to do that, they'd have to choose another
regulatory mechanism.
So the need to identify and provide adequate
protection of those design basis attributes is an inherent
part of the process.
The next bullet deals with change control. The
issue here is that 10 CFR 50.59 is focused exclusively on
the preservation of the deterministic licensing basis. So
it's not an adequate tool to address facility changes that
might affect severe accident performance.
For example, a pressurizer PORV could play an
important role in a facility risk profile by providing the
capability for feed-and-bleed, the once-through core cooling
scenarios.
If a licensee chose to somehow diminish that
capability, the existing 50.59 might fully allow the
licensee to proceed and make that change, because it is not
a design basis event.
However, it could have a very significant effect
upon the facility's risk profile.
NEI has indicated that they agree with the staff
on the need to address these severe accident attributes and
has mentioned that in their guideline documents on
treatment. However, again, the staff is going to need some
additional details. We have a lot of work to do before we
can actually define the process in the way that it will be
applied by the industry.
The predominant concern, at least in my mind, is
that there's some level at which, similar to 50.59, at which
prior staff review would be required before a facility
change could be made. We want to strike a balance between
the facility's ability, the licensee's ability to make
reasonable changes to their facility and to manage their own
risk profile, but also recognize that there is some
threshold that they could reach, hopefully rarely, that we
would want to be engaged prior to those changes being made.
The next bullet, dealing with the adequate
assurance of RISC-2 capability. The fundamental issue here,
in my mind, deals with performance monitoring. Basically,
performance monitoring under normal operating conditions may
not be relevant to the severe accident conditions that might
be seen.
So how will you actually be able to meaningfully
monitor these components as they normally operate and say
that they derive information that's actually meaningful for
their usage in a severe accident environment.
Also, I will point out that NEI has proposed that
we divide the RISC-2 category into two subcategories.
Basically, one is those non-safety-related SSCs that are
subject to some other regulatory treatment, such as fire
protection components or station blackout components, and
also one category where there's no existing special
treatment, no existing regulatory requirements for special
treatment.
So this has led to a distinction between the SSCs
in the RISC-2 box.
Finally, with regard to the adequate assurance of
RISC-3 functionality, again, we have the other side of the
coin with regard to performance monitoring. Performance
monitoring, again, during normal operating conditions may
not provide meaningful information regarding design basis
capability.
So a program that exclusively relies upon, say,
for example, the maintenance rule, may not, in and of
itself, be sufficient, may require some other attributes.
You may have to rely upon other attributes of a commercial
program or other regulatory controls to provide the adequate
level of assurance for the protection of those design basis
functions.
Are there any questions?
This slide outlines how we're proceeding with our
review. Presently, the risk-informed Part 50 core team has
been tasked with developing guidelines for the review of the
South Texas exemption. We will be complete with that task
within the next few weeks.
Following on from that, we're going to develop
acceptance criteria for the review of option two treatment.
I anticipate that this will be an evolution from the South
Texas guidance and will be the basis for our review of the
generic industry guidance.
This means that the staff needs to have a good
understanding of how well the South Texas and NEI proposals
conform to one another. We've had a presentation both by
South Texas and by NEI addressing this topic. There seems
to be, at least on first blush, a good level of agreement
between the proposals.
South Texas clearly did not apply the NEI
guideline. It didn't exist at that time. But they have
participated with NEI in development of their guidance and
largely they conform to one another in terms of their
processes.
This last slide provides the risk-informed Part 50
option two schedule, as it stands at this point. I will
point out this is a tentative schedule that we recently set
up for management review, and some of the assumptions that
are inherent here are still being refined.
If you'll note, for example, we say that in
January 2001, the pilot program would be initiated.
However, in our meeting with NEI on Tuesday, we had some
indication that pilot activities might begin much sooner
than that, perhaps this September.
So some of these schedule assumptions and the
overall timeline here is subject to change as we proceed.
At this point in time, however, we're projecting
that we would complete the final rulemaking to the
Commission by the end of 2002.
DR. APOSTOLAKIS: Do you know who the pilot plants
will be?
MR. WILLIAMS: We don't have specific information
at this point. We know that the first out-of-the-box will
probably be some boiling water reactors. I could speculate,
but that would be all it would be at this point.
DR. APOSTOLAKIS: And where does the South Texas
exemption request fit into this?
MR. WILLIAMS: The South Texas review, right now,
we're anticipating that that will be completely by April of
next year. I'll point out we've characterized the South
Texas review as a prototype versus a pilot, basically as a
demonstration of the concept.
Since they don't conform or did not develop their
process in full conformance with the NEI guidance and
hopefully what will ultimately go into the regulatory
guidance, we couldn't really call them a pilot. They do
play a significant, but distinct role in the effort.
I believe that concludes our presentation.
DR. APOSTOLAKIS: This concludes the whole thing?
You want us to brief the Commission in September on what
you've got here?
MR. WILLIAMS: I guess so.
DR. APOSTOLAKIS: Fine. Any comments or questions
from the members? You will expect a letter from us at some
point?
MR. BERGMAN: We considered this informational
briefing. Of course, if you want us to provide something,
we're certainly happy to get it.
We are coming back to you, though, at the -- I
think it's the September meeting, but it's August 30th,
maybe.
DR. APOSTOLAKIS: Okay.
MR. BERGMAN: Right. And at that point, we'll
have a full Commission paper for you that addresses the ANPR
comments and other related issues and we'll certainly want a
letter from you at that point.
DR. APOSTOLAKIS: In September.
MR. BERGMAN: Right. I think our Commission
briefing is going to be the week of the 18th of September.
DR. APOSTOLAKIS: I don't think there's time to
have another subcommittee meeting. August is a month. But
we don't need a subcommittee meeting before the presentation
to the full committee.
MR. BERGMAN: I don't think so. I mean, that's up
to you, but I don't think so.
DR. APOSTOLAKIS: Okay. Any other comments from
members of the public, NRC staff? Thank you very much.
Very informative.
MR. WILLIAMS: Thank you, sir.
DR. APOSTOLAKIS: Appreciate it. Now, the next
item on the agenda is Mr. Christie's presentation, which is
scheduled to start at 10:30, and I'm advised that I have to
stick to that schedule.
So we will recess for 50 minutes.
[Recess.]
DR. APOSTOLAKIS: We are back in session. Mr. Bob
Christie, the floor is yours.
MR. CHRISTIE: My name is Bob Christie. I am the
owner of a firm in Knoxville, Tennessee, called Performance
Technology. I have been in the commercial electric power
business, nuclear, for about 26 and a half years or so. The
first 15 and a half years was as an employee of the
Tennessee Valley Authority.
The last 11 years, I've been a consultant, not
only for the nuclear business, but also for other places,
such as the railroads and that, basically doing risk and
reliability evaluation.
I am here today to talk about a petition for
rulemaking which was filed last year and to describe it and
hopefully answer your questions about it.
I have been asked and requested by a staff member
of the Nuclear Energy Institute to clarify completely that
the views that I express today are not endorsed by the
Nuclear Energy Institute.
So with that, I'd like to start.
DR. KRESS: Is there any particular reason that
they haven't endorsed this?
MR. CHRISTIE: I have no idea. You'd have to ask
them. This petition is a petition that does not come from
the Nuclear Energy Institute and my views and the views that
I express today, which I explained to you the last time when
I talked to you, and I think it was March 1st, whatever it
was, are the views of myself and a bunch of other people who
have been following this and working this area for many
years.
They asked me to make that statement, I made the
statement.
The agenda today, I'd like to start by talking
about a letter I sent to Dr. Tom King on May the 30th. I
think I'll skip the introduction and background. We'll go
back to it if we have time at the end. So really, I'd kind
of like to do A, C, D, E, F, and then go back and do B, if
we have time, and then summarize at the end.
DR. KRESS: What is the status of the petition?
Has it been --
MR. CHRISTIE: We'll talk about that.
DR. KRESS: You're going to talk about that.
MR. CHRISTIE: We'll talk about that in full
detail.
DR. APOSTOLAKIS: I wouldn't skip the background
completely, though. I think you should --
DR. KRESS: You're going to talk about SONGS and
the background.
MR. CHRISTIE: Okay. We'll go over the background
then, quick. The thing that's really amazing to me is I
believe that we're very, very close to having a rule that's
acceptable to everyone. We've had many meetings.
I guess the first public workshop was back last
September. Then we had another public workshop in February,
and then we had a -- I think it was called a public meeting,
not a public workshop, we had a public meeting in May.
We've also had other interactions and so on.
But at the May meeting, there were six criteria
that the Nuclear Regulatory Commission people were using to
make decisions with respect to 10 CFR 50.44. And so in the
meeting on May the 17th, I think we got pretty good
agreement and pretty good definition of where we didn't have
agreement.
So I'd like to tell you that today. I think we're
pretty close. And let's go over what we discussed on May
the 17th.
The first one has to do with the hydrogen
monitoring, measuring the hydrogen monitoring concentration.
That's their slide 23. And I think we have come to
agreement that the hydrogen monitoring system can be
commercial grade. It no longer has to be safety grade,
safety-related, with all the bells and whistles. That was
my interpretation of what happened.
Where we disagreed is, or I think we disagreed,
that the staff of the Nuclear Regulatory Commission still
believes that there should be requirements, quote, for the
long term for hydrogen monitoring and while these
requirements would allow you to be commercial grade, there
are still going to be requirements and you will still have
to have inspection and so on.
My position and the position of the others that
I've worked with on this is basically this hydrogen
monitoring is not safety-significant, it is not a primary
indicator that is used for anything but to turn on the
hydrogen control systems, which are the recombiners and the
purge systems, and if we make the recombiners and the purge
systems non-safety-related and don't have requirements, then
fine, the hydrogen monitoring is also not safety-significant
and it would be put in a non-safety-significant category,
turned over to the utilities, and the utilities would be
responsible for it.
Not that they're going to immediately go out and
dump or anything like that. They are just the ones that are
now making the decisions.
DR. KRESS: When you say not safety-significant,
that means it has insignificant impact on CDF and LERF. Is
that what you mean by that?
MR. CHRISTIE: Insignificant impact on anything.
DR. APOSTOLAKIS: Have you subjected these to the
Ross' adoption two that he is proposing?
MR. CHRISTIE: In option two, all this stuff isn't
even in the PRA, doesn't get -- this is non-safety -- if you
did an option two on this, this is all
non-safety-significant. It's below the line.
DR. BONACA: Bob, this is the question I have. I
remember when we did review, first of all, an application by
the Westinghouse Owner's Group for elimination of the PASS
system or of certain portions of the PASS system.
I remember that they put the burden on the
hydrogen monitoring system to perform some function in
support of the emergency actions level, because --
MR. CHRISTIE: Severe accident management
guidelines.
DR. BONACA: So I don't remember the exact
details, but I remember that they committed to maintain the
hydrogen monitoring for a specific function in the severe
accident management guidelines.
Now, when San Onofre came with the proposal to
eliminate the hydrogen monitoring system, they took it back
at some point, because they said that this had to go with
the same option on severe accident management provided by
Westinghouse and for that, they needed a monitoring system.
Could you address that point?
MR. CHRISTIE: Okay. Let me explain what happened
with the severe accident -- well, let me explain what
happened with San Onofre. San Onofre went in with a 50.12
exemption request, which you people finally approved, but in
the course of negotiations with that, San Onofre basically
withdrew the application for the hydrogen monitoring to be
declared non-safety.
They put it on hold. They didn't say it wasn't
non-safety. They didn't say it was non-safety. They just
put it on hold and they received the approval from the staff
of the Nuclear Regulatory Commission for the recombiners and
the purge to be non-safety and to pass onto the purview of
the utility only.
Their position still was it was not
safety-significant, it was not safety-related, and they just
put it on hold. The Westinghouse Owner's Group, and I
haven't been following it for PASS very much, but to the
best of my knowledge, what the Westinghouse Owner's Group
have said, and I believe there was a change in the middle of
their submittal.
They started out with the hydrogen monitoring as
being safety-related and they changed it to be
non-safety-related. It's going to serve a function in the
severe accident management guidelines which are not
safety-related pieces of equipment and you don't have to
have safety-related pieces of equipment to do it.
DR. BONACA: I understand. I'm only saying that I
know the reason why they left it in, however, they did not
ask for exemption on that system, was because -- I asked the
question specifically and they answered that they, yes,
would want to go with the WOG for the SAMG and because of
that, they withdrew the monitoring system from the
exemption.
So I think there was a logic behind the reason why
it stayed there yet and I want you to keep it in mind as you
go forth with this.
MR. CHRISTIE: And I haven't followed the
Westinghouse Owner's Group post-accident sampling system
that closely, but I have been told that the post-accident
sampling system WOG submittal changed the requirement for
the hydrogen monitorings in the middle of the application to
move the hydrogen monitoring from safety-related to
non-safety-related and that's where it is today.
It was approved on the basis of non-safety.
MR. SNODDERLY: Excuse me. Dr. Bonaca, my name is
Mike Snodderly. I did the San Onofre hydrogen exemption and
I also did the review for the Westinghouse Owner's Group
PASS sampling.
From my perspective, I believe that if you look at
the exemption request for the PASS, it did credit the
continuous hydrogen monitors, the safety-related continuous
hydrogen monitors, as the way to measure hydrogen and to
support core damage assessment, the Westinghouse Owner's
core damage assessment guidelines.
Also, if you look at Regulation 50.47(b)(9) for an
effective emergency plan, most licensees meet that with Reg
Guide 1.101, Revision 3, which endorsed an NEI guideline.
But that states that a general emergency is a loss of any
two barriers and potential loss of a third barrier.
Potential loss of a third barrier includes whether
an explosive mixture exists inside containment and most
licensees use the hydrogen monitors for that determination.
So just to support and refresh what had happened.
DR. BONACA: Okay. I didn't have enough detail,
and you have provided that. Okay. But I remember there was
a connection. It wasn't in this part of the rule. It was,
however, in the severe accident maintenance.
Now, whether your requirements may be to implement
severe accident management steps and if they are part of the
law, I don't know.
MR. SNODDERLY: The severe accident management
guidelines are a voluntary initiative and as Mr. Christie
points out, yes, we agree that the hydrogen monitors are not
needed to actuate any of the mitigative features in 50.44,
the hydrogen recombiners, the igniters, those types of
things.
So that it could be eliminated from 50.44, the
requirement of hydrogen monitoring. But there still is a
requirement in NUREG-0737, the post-TMI requirements, that
you have hydrogen monitoring, and, also, in how licensees
have met this 50.47 requirement through the appropriate reg
guides.
So as we go through this process, we've got to
keep that in mind and we'll have to go back and reconsider
those types of situations, but I believe the staff still
believes that hydrogen monitoring, although you may not have
to do it with safety-related continuous monitors that are
currently installed, they still would be needed for the core
damage assessment and EP.
DR. BONACA: Thank you.
MR. CHRISTIE: And I think that's a pretty clear
description of where the differences are between the
position we have and what the staff has.
DR. APOSTOLAKIS: Again, I asked you about option
two and you said it's below. How could it be below? If
there is a box there that says non-safety-related,
non-safety-significant, so this must belong there.
MR. CHRISTIE: In the option two, if you didn't
change the rule, this would go into RISC-3.
DR. APOSTOLAKIS: Which is?
MR. CHRISTIE: Non-safety-significant, but
safety-related.
DR. APOSTOLAKIS: Okay.
DR. KRESS: Because it's already designated.
MR. CHRISTIE: It's already. But if the rule, the
petition for rulemaking is approved, that's the whole
purpose, first -- and, see, we're doing box two and -- we're
doing option two and three all at once with hydrogen. Okay.
We're moving it from safety-related, box one, to
box four, by this rulemaking.
DR. APOSTOLAKIS: Right.
MR. CHRISTIE: So, again, that's the situation as
far as measuring the hydrogen concentration.
MR. SNODDERLY: Excuse me. Dr. Apostolakis, I
just wanted to address one thing on your point. If you just
use option two and the criteria of CDF and LERF, yes, I
agree with Bob Christie, it's going to be in the group
three.
One thing I think we all need to keep in mind,
though, is those other regulations, such as 50.47 and EP,
aren't really addressed as one of the criteria for
determining whether something is in box one or box three.
So I think that that's -- and sometimes in the
expert panel, that's considered and sometimes it's not.
Currently, the way the hydrogen monitors and all
the monitors that are required safety meet Appendix E, the
emergency response data system. All those things currently
would be in the low safety, no risk significance.
I think that's one issue that we're -- I don't
think we're disagreeing on the categorization, but how do we
treat that, because there is this acknowledgement that it is
needed for those things.
DR. KRESS: Would that be considered a
defense-in-depth requirement?
MR. SNODDERLY: I believe so, Dr. Kress, but I
think what we're -- the issue, I think, that's being brought
up here is that, yes, if you just apply the criteria of CDF
and LEF, yes, this stuff clearly is not needed to meet that,
falls out, but do we maybe consider another criteria or are
we adequately addressing it through the special -- you know,
how is it going to be treated.
DR. APOSTOLAKIS: Let's go on.
MR. CHRISTIE: Okay. For the next, which is the
mixed containment atmospheres, again, as far as we're
concerned, basically, mixing the containment atmosphere
comes because you have systems for containment heat removal,
either fans and coolers or sprays, some plants have both,
and these systems we're not proposing any change at all in.
We're still going to be mixing atmosphere. The
proposed rule doesn't change that. Nothing changes that,
and we're in complete agreement on that.
The next one is the control of the post-LOCA
combustible gases. The Nuclear Regulatory Commission, on
their slide 25, says remove post-LOCA hydrogen control from
50.44. Complete agreement, we remove it from 50.44.
On the reactor coolant system high point vents,
again, complete agreement.
DR. APOSTOLAKIS: Either you don't use them at all
or --
MR. CHRISTIE: All right. I guess this is slide
26, which is the reactor coolant system high point vents.
Again, we got complete agreement. We're going to keep all
the stuff in for the reactor coolant system high point
vents.
On the slide 27, which is the inert, the MARK 1's and MARK 2
containments, again, complete agreement. We're not going to
change -- no change. We're going to keep them inert.
The last one, and we should spend a little time on
this one --
DR. KRESS: Where will I find that slide?
MR. CHRISTIE: Slide 28.
MR. MARKLEY: Page four.
DR. KRESS: Page four.
MR. CHRISTIE: Page four. It comes as an
attachment --
DR. KRESS: No, I mean the real slide that he's
talking about.
MR. CHRISTIE: That comes as the attachment to the
May 30th letter from me to Dr. King.
DR. KRESS: Okay. I've got that here somewhere.
DR. APOSTOLAKIS: No, no, no. He means this. I
think what Dr. Kress means is the actual slide 28.
MR. CHRISTIE: Right. It comes in the attachment.
You got a letter from myself to Dr. King dated May the 30th
and you have all the slides that we're talking about here.
DR. APOSTOLAKIS: Right.
MR. CHRISTIE: Okay. This is a very -- again,
it's a tough slide to read. We had a very difficult time
with it on May the 17th. It's unclear. And really, as far
as we could tell, it busts into two pieces.
One had a requirement for all plants, and that's to
demonstrate the containment will withstand both short and
long term a specified source, so and so, and then they had
one for MARK 3's and the ice condensers, which is do
something with the MARK 3's and the ice condensers for the
igniters during station blackout.
What we have said, and we'll talk about this in a
minute, is for the large dry containments, we have a
requirement now, we've added a requirement to address the
containment capability during severe accidents.
And I don't know whether the staff of the Nuclear
Regulatory Commission agrees with that one. It's very
unclear what this one was.
The a second part, and this is the one that I
think we need a lot of discussion on, because it got brought
up again in the Commissioners' briefing last week.
The staff of the Nuclear Regulatory Commission
believed that the igniters should be operable during station
blackout. Myself and the others do not understand this
requirement at all, so let me explain what we see for
station blackout and the igniters for the MARK 3's and the
ice condensers, which are the ones that have the igniters.
If you have a station blackout, you have a loss of
all AC power, it becomes basically a timing problem. And
let's take the boilers first. Let's take the MARK 3
boilers.
If you lose all the AC power and your offset power
is lost and your emergency diesel generators are lost, what
you boil down to is you will have the turbine-driven reactor
core isolation cooling. That will supply water to the
reactor vessel.
You will also have the control systems that are DC
powered coming off the batteries and you will also have the
control systems that are AC powered that come off the
inverters, which are powered by the batteries. This is what
you're down to.
At this point in time, and this will go on,
depending on whether it's a four-hour plant in battery life
or an eight-hour plant in battery life, it just depends on
how much battery you have, you will basically not see any
core damage, we think.
I mean, basically, your RCSI, reactor core
isolation cooling system is supplying water, the core is
covered. You're not removing any heat from the containment,
which is kind of worrisome, but you can control it, and, if
that works, everything is fine.
DR. KRESS: You're saying the contribution of that
station blackout sequence to core damage frequency is very
low.
MR. CHRISTIE: That's an automatic, yes. To get
to the point where you have a loss of off-site power and the
failure of all your emergency systems on-site.
DR. KRESS: You've got to have a lot of things
happen. So that particular sequence --
MR. CHRISTIE: Right, that sequence --
DR. KRESS: -- for those plants don't add much to
core damage frequency.
MR. CHRISTIE: To get to that point, we're talking
a very low number on initiating events, plus those
subsequent -- you know, the initiating event is loss of
off-site power and the subsequent event is a loss of all
your emergencies. That's a very low probability event.
On top of that now, you have the situation where
you're keeping the core cooled with the RCSI and you have
control because you've got your DC and your AC power
systems.
And this goes on for approximately four hours. At
the end of four hours, and let us ask yourself what role do
the igniters play during this time. Why would you want to
have them operable?
DR. KRESS: If they were operable, they might
preclude --
MR. CHRISTIE: First off, how would you put them
operable? They require electrical power.
DR. KRESS: That's another question. But if you
did go into core damage, which you say --
MR. CHRISTIE: No, we're not into core damage yet.
DR. KRESS: Then they have no purpose.
MR. CHRISTIE: Right, exactly.
DR. KRESS: But if they did go into core damage,
then they may preclude an early failure of the containment.
MR. CHRISTIE: Wait a minute. Wait a minute. Now
we're going down -- and now we're four hours into it. Let's
say we have a four-hour plant, and the batteries fail. When
the batteries fail, you're no longer going to be able to
control RCSI, even though at Browns Ferry we thought we
could jam the steam emission valve wide open and just take
our chances.
But say we lose now the ability to have RCSI.
Okay. The core -- the inventory in the core is going to
start to deplete, depending on what codes you believe for --
you know, whether you use MAPP or MELCOR. Within a couple
of hours, the core is going to be melted and probably going
through the reactor vessel and laying on the floor.
But if you don't have -- and during this period of
time, if you were able to restore anything, electric power,
what you -- well, in the first part, the first four hours,
if you got electric power back, what would you restore?
Well, the first thing you would restore is you'd
take -- you'd stop using the batteries and you'd try and get
your AC and DC systems on control systems working off your
emergency power systems or off-site.
If you've got off-site back, everything comes on
and you don't even worry about it. But if you've got just
one diesel, the first thing you're going to restore is the
AC/DC. The second thing you're going to do is you're going
to start going down to probably the suppression pool and
start cooling the suppression pool, because HPSI and RCSI,
if you don't -- well, you don't have HPSI.
You've got RCSI. RCSI can't cool -- can't use the
water from the suppression pool forever because it's too
hot.
So if you get an electrical diesel generator back
in the first four hours, you're first going to make sure
your batteries are taken care of and then you're going to go
and start suppression pool cooling, because your HPSI is
keeping you alive and you're not worried about it, and now
you want to start removing heat from the containment.
So that period. The next period of time is where
the core is melting and when the core is melting, again, the
first thing you're going to do, if it's after four hours and
your batteries are gone, but then you get an emergency
diesel generator back, you're going to go first for the
control systems. You're going to want to know where you
are, what's the status of my core, is it completely melted,
is it on the floor or et cetera, et cetera. So that's the
first thing.
The second thing you're going to have, and it's
going to be a hodgepodge with boiling water reactors. What
you're probably going to want to do is even if you melt it,
you're probably going to want to put water on the core.
Probably. That's probably something that you've really got
to consider.
The other thing is you're going to have to start
removing heat from the containment and you're going to
either do it RHR through the suppression pool or sprays or
whatever method you can do, you're going to do it.
Again, we don't see that igniters -- having
operable igniters during this period of time is the thing
that would cause is -- we wouldn't take our emergency diesel
generator and automatically start taking some of that power
off to power up the igniters. It doesn't seem logical to
us.
DR. KRESS: If the rule says you need to have
power to the igniters, all this other stuff is what ifs.
But the question you're asking is should you have power to
the igniters, should that be part of the rule.
And if I were to ask why would I want power to
those igniters, it's if my CDF is low enough in the sequence
already, do I need a conditional containment failure
probability that's very, very low, because I've already got
the CDF low enough.
And does having power to the hydrogen monitors do
anything to my conditional containment failure probability?
I don't know that it does or not. I would suspect it does.
MR. CHRISTIE: I think, Tom, I'm not explaining
myself well. You have X amount of dollars. With station
blackout, you've got X amount of dollars. The staff is
telling us they want to spend some additional money on
station blackout to have the igniters operable during
station blackout.
It makes no sense to us. If I am spending money
on having an additional source of power at the plant during
station blackout, other than my off-site power and my
emergency diesel generators, I'm going to have it powering
my AC and DC control and my containment heat removal
systems.
The last thing on my mind, because I want to
prevent core damage, and so my money is not going to go to
igniters. Igniters don't do anything in the first four
hours. Igniters probably don't do anything in the next four
hours. Igniters may not even do anything in the long run.
We don't see why anyone would spend money on
igniters, on AC power sources for igniters, when the money
would be better spent somewhere else, either preventing core
damage or taking care of the heat removal.
Ultimately, supposing you could never get heat
removal back, you're failing. You're going to fail the
containment. I mean, it's just if you don't have heat
removal, you're going to fail the containment. I don't care
if you've got igniters powered forever.
So this is the -- in our mind, the most -- and
that's why we wrote the rule the way we did or we proposed
the rule the way we do.
DR. KRESS: I wasn't looking at it as an
either/or. I was looking at it as you need containment heat
removal and maybe you need igniters, also.
MR. CHRISTIE: Right. But from my standpoint,
from a technical standpoint, if we are going to go and
provide additional electrical power sources other than what
we've already got, we're not going to put it on igniters.
If it were cost-beneficial, we'd probably put it
on AC and DC control systems, we'd probably put it on heat
removal, on boilers, because we want to keep water in the
core, and so on and so forth.
Go over to a pressurized water reactor. Again,
the same thing. You lose the off-site power, you lose your
emergency AC. What are you down to? Well, you're down to
the turbine-driven emergency feedwater systems and, once
again, the DC and the AC systems.
On a pressurized water reactor, this is going to
go on for X amount of time. All right. Now, depending on
what model you use for the reactor coolant pump seal LOCA,
you're going to have a LOCA at the same time because your
steam generators are cooling, but you're also losing water
inventory off of the primary system and you're not
replenishing it, because you have no AC power and there's no
turbine-driven pump that supplies water to the reactor
pressure vessel.
So for the first four hours, again, you're in a
situation where you're cooling with the steam generators and
your AC and DC power control systems are working fine. You
know what's going on, so on and so forth.
Once again, if we restored anything during that
period of time, we wouldn't be worrying about the igniters.
We're going to go -- if we get something back, the first
thing we're probably going to go do is start safety
injection, the higher pressure safety injection pumps and
restore the inventory we lost off of the reactor coolant
pump seal.
So that's -- again, it's this priority of things
that doesn't make any sense to us. If I were going to have
an additional power source on the plant, I'm not going to
put it on igniters. It makes no sense to us.
The same goes when you start to melt the core.
Now, when you start to melt the core and if you get the core
on the floor, et cetera, et cetera, you're, again, going to
be faced with a choice, hey, do I turn on containment heat
removal sources or do I try and get safety injection working
so that I pump water on wherever it is, dropped in the sump
at the bottom of the reactor vessel, wherever it is.
But you're not going to worry about the igniters.
Once again, it's containment heat removal.
So from a technical standpoint, we don't understand the
staff's belief that having an additional power source to
make igniters operable at MARK 3's and ice condensers --
why? And what we've said to them is, if you've got a
problem, identify it. We have still not seen any technical
justification or even know what exactly the problem is.
And then if you've got the problem, go put it in
the context of the 51.09, the backfit, because then we'll
all understand it, we'll understand what the problem is,
we'll understand what the alternatives you're proposing are,
and we'll understand what the cost-benefits are.
So that's where we are on that.
Okay. Now, if you want to talk background.
Again, this work comes out of the Arkansas Task Zero and the
San Onofre Task Zero, and the objective of those pilot
programs, we wanted to have a more objective and efficient
way of doing business.
This is what we talked about before. We wanted to
take the whole plant, we wanted to consider a whole plant
package, which included cost generation and risk.
DR. APOSTOLAKIS: What happened to the whole plant
study, by the way?
MR. CHRISTIE: It's gone.
DR. APOSTOLAKIS: It's gone.
MR. CHRISTIE: You can't get any -- it appears
clear that the staff of the Nuclear Regulatory Commission
are not interested and we can't interest them in the whole
plant study, as far as I can tell.
So what we're down to now is working off of
specific pieces. Though I think that's a mistake and we'll
talk about that a little bit later.
And, again, the basis of what we said is that the
primary responsibility for the public health and safety lies
with the people who run the plant. Their regulatory process
is only good for public health and safety. We've also got
that the public health risk is different for each nuclear,
and it changes with time.
We have addressed, we thought, in the whole plant
study, all the major problems that were placed in the Kemeny
report, which is the President's report on Three Mile
Island, and the best definition I saw of them was Dr. Thomas
Pickford's separate opinion and we thought the whole plant
addressed every one of those items.
We also believe that we don't have that much time
to do all this stuff. We've got to get more efficient and
effective, because basically, in an economically deregulated
power industry, if you're not effective and efficient,
you're not going to be a producer of power very long.
So the more effective and efficient we go, we
believe the best definition of what's going to happen to the
nuclear power plants in the future is contained in this
paper by Mr. Shiffer, who is a retired executive out at
Pacific Gas & Electric, someone who has lived through it on
Diablo Canyon and, in this paper, told us what the future
would look like.
Now, just a quick -- and we've been all through
this before with you. If you look at the San Onofre
evaluation report, again, this we've known for 20 years.
The overall public health risk is dominated by severe
accidents where the core is damaged and containment is
bypassed or breached.
DR. KRESS: Before we take that one off, let me
ask you a philosophical question about that. Should NRC
just be concerned with the dominant accident sequences or
should they be concerned with accidents that may be more
frequent, but not as dominant in terms of risk, but have
some consequences?
That's the philosophical question.
MR. CHRISTIE: Tom, you know, when I'm talking
about the whole plant, you -- and I talked to you on March
1st. To my mind, what the nuclear industry should be
shooting for is what I call the whole plant study.
We should know from top to bottom what that plant
represents with respect to public health risks. We should
know it. I mean, we should know what the health effects
are. We should know what I call source term.
I look at it from the standpoint of a PRA. From
the standpoint of a PRA, out of a level three, I get source
terms to the people. We should know what those source terms
are. We should -- they're in categories. We should know
what the probabilities are, we should know how much
tellurium and cesium.
We should know that. We should have that
information for every plant. To go back to the output of
the level two, we should know what the plant damage states
are and level one and level two in the containment event
tree. We should know all of this material.
We should know it all from top to bottom. We
should know what the systems are responding, you know, that
it's a high probability, we should know it all.
When we get that information, we ought to make the
-- the plant ought to be able to determine for themselves
what level in there should we go to to make sure that we
have provided the adequate protection of public health and
safety.
They're almost invariably going to go to lowest
level possible. They're going to go down to system, because
that's what they can control.
But we have to know the whole picture, because I'm
not smart enough to know the whole picture without doing the
whole picture. So that's -- my philosophical thing is we
ought to consider everything, every accident -- you know,
risk assessment doesn't say, hey, I only consider the ones
that have a frequency greater than so-and-so. They take
every frequency.
They don't consider just single failures. They
consider every failure possible. They don't consider, hey,
we can't have this plant damage. They consider all plant
damage. That's the beauty of the risk assessment.
So that's what I'm --
DR. KRESS: I agree with you. The question is
what should the NRC concern itself with in terms of their
activities and rules and so forth.
MR. CHRISTIE: They start from the top. If they
are absolutely convinced we meet the top, why do they go any
further? If you meet the goals, why are you going any
further? The rest of it belongs to the utility.
See, I look at the thing, there's a certain amount
of expertise in the Nuclear Regulatory Commission. They
should focus on the things that they can do well and that
they can add to value.
The value that they can add is that they're
nuclear. We don't have a coal regulatory commission. We
have a Nuclear Regulatory Commission.
If you wanted to protect against coal boiler
explosions, would you create a coal regulatory -- no. You
let the utility handle it.
DR. KRESS: I guess where I may different a little
from that is it seems to me like the goals of NRC are not
just the two quantitative health objectives. They have
goals that are different than those and they have to do with
controlling things like worker exposure and controlling
smaller releases of higher frequency.
There are rules in there that deal with those kind
of things, and I call those goals, also. And I don't know
where NRC should --
MR. CHRISTIE: Do you believe -- you know, the
nuclear business, in my time, has undergone tremendous
revolution. It's phenomenal to me now today that you can
have nuclear power plants with a total quantitative dose to
all the workers at the plant is under 100 rem.
I mean, we used to do 500 rem. Okay. Now, that
happened in my lifetime and it didn't happen because the
Nuclear Regulatory Commission dictated it.
DR. KRESS: It was because the guys at the plant
--
MR. CHRISTIE: The guys at the plant are not dumb
people and they have -- and I'm not afraid to admit
self-interest, man. We're going into a private enterprise
system in which our survival is necessary.
But the beauty of it all is, and as you heard me
say this before, you can't have a safe plant that isn't a
good economic plant. You can't have a good economic plant
that isn't a safe plant. It doesn't work that way.
You will do things right across the board. The
guys in maintenance ops, engineering, et cetera, they don't
-- no, it's a balance of plant, I'm going to do a shitty
job, or it's a balance of plant, I'm going to do a great
job, or it's safety-related, I'm going to do a great job, or
it's safety-related, I'm going to do -- they don't do that.
They do a good job, and so from my standpoint,
there's an absolute role for the Nuclear Regulatory
Commission. It's there. People have a fear of nuclear and
they have created, through law, the Nuclear Regulatory
Commission. I think you're a good thing.
Okay. I mean, they haven't created a coal because
people don't think that coal kills people to the same degree
they do about nuclear.
So the Nuclear Regulatory Commission has a role
and they can fill it, great, but they ought to focus on the
things that they can do the best and the part that's the
best for them is the nuclear part.
What's the health effects part? You know, we've
ignored that for almost ten years now, as far as I can tell.
DR. APOSTOLAKIS: So you would like every unit to
have a level three PRA.
MR. CHRISTIE: Absolutely. Absolutely.
DR. APOSTOLAKIS: Well, let's see what --
MR. CHRISTIE: I don't know. I think we are
derelict in our duty if we don't. When I was at the
Tennessee Valley Authority, in charge of PRAs, every PRA we
did was a level three, every one.
DR. APOSTOLAKIS: As you know, the trend now is to
work with LERF and CDF.
MR. CHRISTIE: That's because you made it so. I
didn't make it so and some of the people at the plants
didn't make it so. Some of them still have level three and
we still use them.
Going back to -- again, the San Onofre safety
evaluation report, it's not the design basis accidents,
again. It's the severe accidents, et cetera.
The stuff that we put in the plants for design
basis accidents don't work in severe accidents. They're way
under-sized, et cetera, et cetera.
Paying attention to design basis accidents can be
detrimental. In the case of San Onofre, it was the
distraction of the operators because they're paying
attention to a non-safety-significant piece of equipment, at
the detriment of the safety-significant equipment, and we
want that.
So I guess the things we learned out of the San
Onofre --
DR. APOSTOLAKIS: I guess I have to understand
that a little better.
MR. CHRISTIE: Sure.
DR. APOSTOLAKIS: What is this distraction we're
talking about? It seems that's a high level statement.
They have to do an extra thing so that --
MR. CHRISTIE: If you have a design basis set of
things and you do it, one of the things is that you have as
part of the design basis, all the 50.44, et cetera, et
cetera, and you will have to have hydrogen monitoring in
place at X amount of time after an accident.
If you follow the NUREG-0737, it was 30 minutes,
but now, because of Arkansas Task Zero, a lot of the plants
have moved to 90 minutes, et cetera. But some of the plants
still have the 30-minute requirement.
What it means is that one of the reactor operators
in the horseshoe, and, generally, if you're at minimal crew,
there's only two, at some point in the accident, as dictated
by the rules, has to pick himself up off out of the main
boards and go set up the secondary boards, because almost
all these things are not on the main boards.
It's not something -- you have to go to back
boards and hook things -- you've got to coordinate. That's
the other thing. You've got to start coordinating. Health
physics has got to get in, chemistry has got to get in, ops
has got to get in, maintenance has got -- it's a whole
process thing.
And you just pick somebody up out of the control
room, paying attention to things like, you know, what are
the thermocouples in the core telling us, what are the
radiation monitors telling us. It goes away.
DR. KRESS: Just to start up the hydrogen system.
MR. CHRISTIE: Just to start up the hydrogen
system, which we all agree doesn't work for anything that
really counts. That's the distraction.
DR. KRESS: And he could be using that time to do
other things.
MR. CHRISTIE: Right. Hey, monitoring what your
thermocouple is telling you, what your heat removal, making
sure your steam -- if you're a pressurized water reactor,
making sure your steam generators are working correctly,
watching your pressure/temperature curves, et cetera, et
cetera.
All these things that we put in since Three Mile
Island, now we're pulling a guy up and away he goes. And
it's not that one single operator can't do it, they can do
it. But can they do it as well as two? Probably not.
And when they get near drills and that, you know,
they get -- well, anyway, it's just not right and we've --
you know, and I think the staff of the Nuclear Regulatory
Commission agreed. They approved the Arkansas, they
approved the San Onofre, and we're moving towards rulemaking
and we're getting agreement on a lot of things.
So anyway, my read is the important things that
we've got to pay attention to with severe accidents, we've
got to focus on containment integrity. The existing
recombiners and purge don't work and the existing
procedures.
And this is what we got out of San Onofre.
Following the February meeting with the Nuclear Regulatory
Commission, it became clear to us that it wasn't -- the
rulemaking was not going to be something that happened
tomorrow.
So what we did is we started an effort in the
industry to go out and now we're going to produce exemption
requests similar to the San Onofre exemption request and
file it under the 50.12 process.
So this is the results from the first six plants
that we looked at under this process. So what we're
interested in here is what are the action levels, what's
your design pressure and your failure pressure, what kind of
system do you use in the plant, and when do you use them and
how permanent are they and all the rest of that kind of
stuff.
What came out of this study is that, man, there's
a wide variation in the implementation. I mean, we were
working off of San Onofre, which is basically recombiners
with a backup purge that was never used. And then we found
that at the plants that the recombiners were either off-site
or on a warehouse on-site or somewhere.
So if you wanted to do something with hydrogen in
the short term, you were going to have to use the purge.
Also, believe it or not, they have systems called
repressurization systems, because if you do design basis
work, what happens is you don't reach the action levels in
hydrogen until days into the accidents and by that time, you
have cooled the containment to such a point that you don't
have any driving point, any driving force to move the stuff
out, the hydrogen out of the containment. So you have a
repressurization system.
This is caused by design basis accident analysis.
So theoretically, you've got a system in a plant, if you're
using purge, the way you have to pump up the containment to
move out the hydrogen.
So we saw this and the recombiners, some of them
were off-site, some of them were on-site, et cetera, et
cetera.
What we saw is the use of the pressurization purge
and the moveable recombiners, that's dangerous. It's
dangerous to both the workers on-site and the people
off-site.
If we have a severe accident and somebody opens up
a purge valve, the calculations on the inner system LOCA and
the steam generator tube ruptures are going to be dwarfed in
comparison.
That's just a fact of life.
DR. KRESS: How big are those valves?
MR. CHRISTIE: Okay. The six we got, we got a
six-inch, a four-inch and 48-inch butterfly.
DR. KRESS: Pretty good size lines, aren't they?
MR. CHRISTIE: Well, 48-inch butterfly is fairly
big. They're using the normal purge, but they got a stop in
it at 15 degrees instead of 90, which they -- then the other
thing is, what are these things going to do?
Suppose you really did, in a severe accident, open
up a purge valve. You're going to saturate the HEPA filters
without even blinking. They're going to be ineffective to
beat the band, and who knows what's going to happen to the
valves. The junk that's flowing through those valve paths
are is just phenomenal.
I wouldn't -- again, I think everybody agrees it's
not a good thing to do. No one would recommend opening a
purge valve in a severe accident. Simple thing. No one
would recommend hooking up a recombiner. We got recombiners
that are stored off-site or stored on-site, where you have a
pad right next to the reactor building containment, and
theoretically, you're going to go hook up a recombiner in a
severe accident.
Now, the doses at Three Mile Island were measured
outside the reactor building, if I remember correctly, were
measured in the tens to hundred R per hour range. You
believe the workers are going to go out there and hook
anything up? It's not going to happen, and we know that.
You see, it's not something we don't know. The
other thing we checked out is that on all the large -- these
are all large drives. What's the containment capability?
Can you stand the burn without the recombiners, without the
purge, without the monitors, without anything?
Fine. As far as we can tell, everybody has got
more than enough capability to withstand a burn. Three Mile
Island did. It was designed for 50 psi gauge, it probably
had an ultimate of about 150. It stood 28 without even
blinking.
And the hydrogen production rate at Three Mile
Island was probably about as great as you can get, when you
think of the zirc water we did. We drained it, we threw the
water by it as we were draining it, then we filled it again,
we drained and we threw the water by it again, then we
drained it and threw the water by it.
I mean, if you were talking about how much
hydrogen can you get out of the zirc water, you'd run a
Three Mile Island accident. So we had, what, 45 percent
zirc water, somewhere in that neighborhood, and about an
eight percent containment volume and it burned and got a 28
gauge.
The large drives, they can stand it. It's not --
okay. Here's a personal belief of mine. I just don't
like going to the plants and having the plant people
understand that they're writing procedures for design basis,
where the reality is they're not going to follow them, and
if they did follow them, it was going to really be hurting
people.
Now, these are not dumb people. Okay. But their
problem, again, is the application of probabilistic risk
assessment at plants across the United States is not
uniform. Not everybody does use PRA across the board.
So you've got to be careful. Some plants are
still living in design basis space to a much greater degree
than others.
So my problem is I don't like knowing that we got
in the plants the potential for problem, knowing what the
solution is, and we can't take immediate action.
Now, the plants are going to turn in their
exemption requests, because they don't believe the
rulemaking is going to be anything that's going to be fast,
and the exemption request will take care of it, because
we'll get rid of the recombiners and the purgers and the
hydrogen monitors, et cetera, and you'll never have to worry
about it. It will become blanked off for purges, et cetera.
But that takes a while. I mean, you know, we're
thinking maybe about two in the month of July and a couple
more and so on. And it just seems weird.
Now, we've had some discussions. Mr. Mike
Snodderly just told me today there may be another way.
Maybe we can go in and change the emergency operating
procedures generically type of thing.
I suggested in my letter of May 30th an
information notice to let people know that they shouldn't be
doing things like opening purge valves and moving
recombiners in a severe accident.
So I think we're going to do something. It's
just, myself personally, it takes a while. It just flat
takes a while.
Why do we have a system where we have a known problem with a
known solution and it takes the bureaucracy an awful
inordinate amount of time to get the solution solved?
All right. Let's go. We're running out of time,
but we'll see if we can get through.
Let's go the proposed rulemaking. The first thing
we wanted to do was change Appendix A, Part 50, Appendix A,
criterion 41.
If you look at criterion 41, what it says is
you'll have a hydrogen control system and what it's going to
do, it's going to reduce the concentration and quality of
fission products released in the environment by postulating
accidents and the control of the concentration of hydrogen
or oxygen to the other substances in a containment
atmosphere following postulated accidents.
Okay. So this is what it says. It says we're
going to reduce the concentrations that can get out and
we're going to control the hydrogen in. All right. And
it's going to be postulated accidents.
Okay. Well, we know that the postulated accidents
don't work. So when we were looking at a GDC and you were
asking how are you going to risk-inform the GDC. Okay. The
first thing we're going to do is we thought we'd take out
the stuff about the postulated accidents.
Providing things to reduce the concentration of
fission products and to control hydrogen and oxygen for
postulated accidents, that doesn't work in risk-informed
space.
So what we said is, okay, let's write it this way.
We're going to have systems to control fission products,
hydrogen, et cetera, et cetera, to assure that the reactor
containment is maintained for accidents in which there is a
high probability for fission products to be present.
We moved it out of design basis space into severe
accident space. Now, in some of the comments to the
rulemaking, they said, well, you're going to have to define
high probability. I agree, we're going to have to define
high probability, but the reality is we already got the tool
to do that. We got the risk assessments and every plant in
the United States can define the sequences with high
probability.
Now, where they cut it off or where everybody cuts
it off, we'll argue about that till the day I die. But the
reality is the plants have the tool, and so we've got this
-- we re-created a GDC or a criterion to move it from design
to severe accident space. We think we've done a good job.
So we knew we had to change the GDC, because if we
had changed 50.44, but we didn't change the GDC, then we're
still in the postulated accident space, et cetera, et
cetera, et cetera. It wouldn't work. So we've got to
change the GDC, if you want to go to severe accident space.
Inerted containment, no problem. MARK 3 and ice
condensers have to have the igniters, no problem. Leave it
the same. We added one and this one is causing a lot of
consternation.
We thought it was pretty simple. What we said was
if you're a large dry and you're depending on the
containment capability, which is what you're doing now, all
the plants in the United States with large drys depend upon
containment capability to stand the burn.
If that's what's going on, why the regulation that
says withstand a burn? Okay. Regulation could correspond
to risk. If the risk is the containment is going to
withstand it or not, then write your regulation that says
it.
So that we wrote it, say, and we put in words and,
man, these words caused trouble, based upon realistic
calculations, can withstand, without any hydrogen control
system, hydrogen burn for accidents, again, with a high
probability of existing -- of causing severe -- you know.
But to me, this is the words that you got to have
in severe accident space.
Now, the beauty of this is every large dry in the
United States has already done this. We've all done
mid-core. We all went back after Three Mile Island and all
of us looked at it, the NRC looked at it, the industry
looked at, and all of use evaluated the ability of the large
drys to withstand the burns.
We all evaluated it in the 51.09 backfit space.
We all said they can withstand the burns, we don't need the
igniters in the large dry.
So what this proposed rule says, let's make our
knowledge that came out of Three Mile Island and all this
stuff from mid-core and so on and so forth, let's make it
correspond to what we're doing today. We are basing it on
the ability of large drys to withstand the burns. Write the
regulation to say large drys withstand the burn.
DR. KRESS: When you talk about hydrogen control
system, does that include something to be sure the hydrogen
is mixed and doesn't reach --
MR. CHRISTIE: Yes. That's the other part. We'll
go back in the 50.44. We didn't change any of that mixing.
DR. KRESS: That's still part of it.
MR. CHRISTIE: Right. This is a whole package.
DR. KRESS: Then why did you choose 75 percent?
MR. CHRISTIE: Because that's what is in there,
that's the igniter.
DR. KRESS: That's already in there.
MR. CHRISTIE: If you had a large dry that
couldn't withstand a burn, then you go through the backfit
process to see whether you put the igniters in. If the
backfit process says put the igniters in, you put the
igniters in. That's all this proposal will say.
DR. KRESS: Okay.
MR. CHRISTIE: It's, we think, pretty simple and
it says, hey, this is what we're doing out there in the
world, write the regulation to say what you're doing in the
world.
We wanted to make the regulations and the risk
comparable. I mean, that's the whole purpose of
risk-informed performance-based regulation. And we think
we've done it. That's what we think.
And this is just the same thing for the high point
vents.
DR. KRESS: Let me ask about large drys. Clearly,
in my mind, they can withstand the hydrogen burn, but a
hydrogen burn with igniters spreads the pressure out over a
long period.
MR. CHRISTIE: I'm not sure that that's true.
DR. KRESS: It burns the hydrogen as it goes in,
supposedly.
MR. CHRISTIE: It depends on when they're turned
on and how fast the stuff goes.
DR. KRESS: Yes, but that's the general idea.
Whereas if you didn't have igniters in those, then you could
build up the hydrogen to a pretty high level. They're
designed so you don't get up to detonation levels,
generally, but you can get up to a pretty high level and
then ignite them by some ignition source and you get a much
different kind of pressure spike.
MR. CHRISTIE: Three Mile Island is proof of that.
DR. KRESS: Yes. Would there be any difference in
the nature -- I'm also assuming if you've got that much
hydrogen in there, you're in a severe accident and you also
have fission products present at the same time.
MR. CHRISTIE: Sure.
DR. KRESS: Would there be much difference in the
release of fission products and their subsequent
consequences between those two scenarios?
MR. CHRISTIE: No, because in order to get the
fission product releases, if you got that point, just like
we did at Three Mile Island, you're going to have to have
heat removal. Containment heat removal has got to fail.
Whether you burn it fast, slow, it doesn't matter. What's
going to happen is the containment is going to stand the
burn, whether it's slow or fast doesn't matter.
DR. KRESS: I'm assuming that you still have
leakage, normal leakage path, and --
MR. CHRISTIE: But the amount of material that's
getting out in the normal leakage path is so infinitesimal
and such a small -- I mean, what -- we're not going to --
DR. KRESS: You say it's not worth worrying about
that difference, is what you're saying.
MR. CHRISTIE: Not worth worrying about. Not
worth worrying about. Not that I can see, Tom. I mean, you
know, we -- I think. And Lord only knows that we've spent
gobs of money.
DR. KRESS: Suppose the difference between those
types of burns meant you -- in the one burn with the
igniters, you were below 10 CFR 100, and the other burn, you
were just a little above it. Is that something that --
MR. CHRISTIE: I'll tell you this, flat. If
you're in severe accident space --
DR. KRESS: You don't worry about 10 CFR 100.
MR. CHRISTIE: 10 CFR 100 is long gone, in my
mind. If the tech support center is worried about 100, when
we're in a severe accident, especially Three Mile Island, we
--
DR. KRESS: They're focusing on the wrong thing.
MR. CHRISTIE: Yes. We ought to start replacing
that tech support center fast.
I'm almost close to being on time. To summarize,
I have and others have -- a sufficient knowledge exists to
change the regulation of combustible gas control. We don't
need anymore studies, we don't need anymore work. We don't
- you know, we can spend hundreds of millions of dollars
more if we want to, but we don't need to.
We're done. I mean, enough is enough. I
absolutely believe that if you're going to rewrite the
regulations, you've got to focus them on the severe
accident. I mean, that's just the way you've got to write
the regulations.
I know that's a major cultural change with the
staff of the Nuclear Regulatory Commission and they are also
included as a major regulatory change for the staffs at the
nuclear power plants, but we've got to get through that. I
mean, we've got to.
In order to have more effective and efficient
regulations, we've got to get through that.
DR. APOSTOLAKIS: Actually -- go ahead.
DR. KRESS: Go ahead. I've asked enough. You go
ahead.
DR. APOSTOLAKIS: Isn't the notion, the very name
severe accident tied to design basis accident, the concept
of design basis?
MR. CHRISTIE: I don't think so.
DR. APOSTOLAKIS: Beyond design basis is severe.
DR. KRESS: In a sense, that's an arbitrary thing,
but to say the regulations ought to focus on severe
accidents, which is what I heard right there, seems a little
bit problematic to me, because the reason the severe
accidents are the risk dominant ones is because the
regulations have gotten rid of all of the high frequency --
MR. CHRISTIE: I disagree with that completely. I
disagree with that completely.
DR. APOSTOLAKIS: But I think you can rephrase it.
Let's say we start with a clean slate. Instead of using
terminology that is really tied to the existing system, what
you're really saying there is focus on risk.
DR. KRESS: Yes.
MR. CHRISTIE: Okay. That would be appropriate.
I accept that.
DR. APOSTOLAKIS: Which now will lead you -- what
does it mean to focus on risk? Well, you are going to the
sequences of events that dominate that risk.
MR. CHRISTIE: That's right.
DR. APOSTOLAKIS: And you are free now from design
basis or whatever. You look at the sequence and say what's
the best job I can do to make sure the risk is low.
DR. KRESS: I think that would be a good approach.
DR. BONACA: I think there is space for both
needs. When you design ECCS systems, you are using some
requirements of the existing law that make sense. You are
designing how much water do you need to deal with some
limiting accidents of some type.
Now, when you evaluate the response of other
systems, you may need to focus the way you're saying. What
I'm trying to say, you cannot exclude it. It's the same way
in which, after TMI, we discovered that using the analysis
made to design the plants, to train the operator was wrong,
because life, things don't move the way that the analysis
for designing the plant moved.
So in designing the plant, you are looking at
limiting events to build equipment that will deal also with
the limiting event. In training the operator, you develop
analysis that gives you what will really happen in most
cases, so that the operators are able to deal with those
issues.
So I'm only saying that to say we only should
focus on severe accident is somewhat limiting insofar as
regulation is concerned, because you still have some design
objectives that you want to maintain there. Who knows?
Maybe we'll beat another plant ten years from now.
DR. APOSTOLAKIS: Yes, but that's not in the
present. Anyway, we understand the spirit of this.
MR. CHRISTIE: Yes. We've been through this many
times. Okay.
The next thing is when we put together the
proposed rulemaking, again, it's a first of a kind and we
were doing the best job we could.
But what we thought -- and, see, this is our
framework. Our framework starts on public health risk is
dominated by severe accidents, with containment bypass and
breach, probabilistic risk assessment is the best tool to
measure it.
You're going to focus on the sequences that are
most significant, and so on and so forth.
So our framework just said, okay, let's start with
that kind of a philosophical approach to the whole problem
and then let's just go ahead -- and what we said is let's
retain whatever is in there that's effective and efficient.
So if you got high point vents, if you got
inerting, if you got igniters for the MARK 3, and so and so,
fine, retain it. Just keep it. No sweat. Add where
necessary.
We added the section that had to do with the large
drys, checking their containment capability.
Now, we would believe that that would be an
appropriate addition to the rulemaking process to cover the
large dry plants.
In essence, we've already done it. Let's just put
it in the regulations. To me, it passed the backfit rule.
DR. KRESS: Because you've already done it.
MR. CHRISTIE: Right.
DR. KRESS: It's not going to cost you very much,
is it?
MR. CHRISTIE: Right. You've already done it, it
doesn't cost you anything, and it meets the backfit rule.
And then delete whatever is not effective and efficient.
We wiped out, and I think we got agreement now, we
wiped out all the post-LOCA design basis hydrogen
requirements. I mean, to me, it's a simple problem in just
-- I don't need option three, I don't need option two. I
can sit down and write a rule to address the specific thing
just doing exactly what I said.
Go through, identify the things that are important
in probabilistic risk assessment space, retain what's
effective and efficient, add where it's necessary, and
delete whatever is left.
I absolutely believe this is -- this petition for
rulemaking is a risk-positive thing. By that, I mean the
potential for health effects on people surrounding the plant
will be less if this petition for rulemaking is approved
than if it's not.
We have identified certain problems with the
existing regulations, which have to do with distracting the
operators, having the potential for purge valves open,
having the potential for guys wandering around the yards
after severe -- you know, et cetera, et cetera.
We can eliminate those. We can have not only a
safer plant, but a more cost-effective. I think it's -- why
aren't we doing this tomorrow? I mean, that's the thing
that's driving me the nuttiest.
It's everybody comes out ahead. I sat there in
that meeting with the Commissioners on the 20th and had
people come up and say the industry is only interested in
the economics and we'll -- you know, that's all we're --
we're not. We're interested in doing things that make the
plants better, both from a safety standpoint and an
economic.
Anything that makes it better, and both is our
first priority.
DR. KRESS: What is the status of your petition?
MR. CHRISTIE: You'll find out this afternoon. I
hope you ask, and ask well.
DR. BONACA: I have a question. On your slide C,
where you're talking about basing the removal of -- for dry
containment based on the reactor containment capability.
MR. CHRISTIE: Right.
DR. BONACA: For the first time really, you are
tying a requirement to a severe accident assumption of
performance in the containment.
What I mean is that if you look at the
containments, the way they are today, they are designed to
meet whatever the design requirement, assuming the design
basis, say 50 psi capacity.
And then in your presentation, you're saying 140,
130 psi capability. We made these estimates for the PRAs.
They were based on the original design of the containments.
Now, we know containments with aging go through
relaxations. There are relaxation of tendons and there are
requirements that by the time they get down to certain
values, these tendons be retensioned and things of that
kind.
But that's an interesting concept, because you are
tying a specific requirement to a performance, which right
now is not being regulated. It's just an estimate.
And the question I have is, for example, would it
be a problem for a containment?
MR. CHRISTIE: To the best of my knowledge, it's
not. We've already been through this. It's not a problem
for the containment.
DR. BONACA: No, no, no. We haven't gone through
this, I'm sorry. We have used the original design of the
containments to perform an estimate of their ultimate
capability. But the fact is when you monitor containment
tendons performance, you allow them to relax, until they get
to a certain limit, where the capability for design basis
used is challenged and then you are going to replace and
retension and so and so forth. You have programs to do
that.
So I'm saying that the age of a containment, its
ultimate capability may not always be at the level we use
for the IPEs or the PRAs.
MR. CHRISTIE: Okay. And, again, I'm going back
to the -- we've had a test case for large drys and hydrogen
combustion. It's called Three Mile Island Unit 2. In
there, this was a containment designed for 50, probably had
an ultimate of 150.
We produced hydrogen in Three Mile Island in
bushels, probably more than we're ever going to ever produce
again. The spike was less than the design. Okay.
We can argue, hey, it might be 30 psi if we had
done something different, et cetera, et cetera, but the
difference between 30 and 150 is -- fine, maybe 20 years
from now, the containment ultimate is 135. I don't care.
I mean, as long as we've got this kind of tool
that allows us to put these things in perspective and to
make decisions to spend money, we've got to use it.
If we don't use it, then we won't be as effective
and efficient. And I'm the last person in the world to say
it's the perfect tool, I'm the last person to say that it's
going to be fixed in concrete and we're never going to
change our knowledge base and what we know and understand.
I'm the opposite. I think it's going to change
constantly and we've got to be -- and I'm with you. We've
got to be aware of those.
But what I want to focus on is the things that are
safety significant. I want to stop spending the money on
the things that aren't safety significant.
DR. BONACA: I agree with you 100 percent.
MR. CHRISTIE: Okay.
DR. BONACA: But there has to be some defensible
technical basis for everything that we are going to discuss
and accept.
I'm saying that I see the reference here to the
ultimate capability of containments. There has been a
criterion in here proposed that bases itself on that
capability and I'm saying the capability, however, is not
one that is guaranteed.
In fact, it varies because all the monitoring
systems for the capability are not focusing on the ultimate
capability, they are focusing on the design pressure of the
containment, which is well below that.
MR. CHRISTIE: I do not read --
DR. BONACA: That is what's being preserved. What
is being preserved is a design capability of the
containment. That's all I said.
MR. CHRISTIE: I don't see anywhere in that
proposed rulemaking that says that we're using the ultimate
capability. We're just saying that the large drys are going
to check their containment capability. We don't use
ultimate capacity. We just say for high probability events,
check your containment capability.
Whether you use design, whether you use ultimate,
whatever you do, that's for the people at the plants to
decide how to do it, and they've done it.
Now, the last thing is, and this goes to the
schedule and where we stand. You've got to remember that
this rulemaking didn't come from me as a rulemaking effort.
It came from me as a letter to the Commissioners saying
based upon what I read in the San Onofre safety evaluation
report, we've got a problem and here is my solution to the
problem.
And the Commissioners sent it down to the Office
of Nuclear Reactor Regulation for fix. The fix that Nuclear
Reactor Regulation and I have worked out is the rulemaking.
This is a rulemaking. This is not part of option
three, it doesn't depend on option there. When we agreed to
rulemaking, it had nothing to do with option three.
The letter I sent back in to NRR -- and I was
dealing with NRR and I'm still dealing with NRR on the
rulemaking -- it says fine, if you want to take this over to
the option three people in Research and treat it as one of
the things that they should be using as the first set of
things to do, I have no problems with that. But this is a
rulemaking.
Okay. The status of it is today, the people who
are doing option three tell me -- well, first off, in the
February meeting, they told us they'd have recommendations
to the Commission in June. Now, as I understand it, the
recommendations go to the Commission in August, but they'll
talk to you about that I hope this afternoon.
But it's not a rulemaking. The recommendations
that they're going to make to the Commissioners in August
are not -- they were explicit that it's not going to be a
rulemaking.
What they're going to send is something to the
Commissioners that's going to recommend something and then
they're going to wait for the Commissioners to make a
decision as to what to do and then they're going to start a
rulemaking process.
And I'm looking at the thing and I'm saying to
myself, wait a minute, we sent it in, we didn't send it in
as a rulemaking, but then we agreed that the rulemaking was
the best way to handle the thing, and you're going to send a
recommendation up that doesn't say rulemake.
It doesn't make any sense to me. Now, I don't
understand the bureaucracy at the Nuclear Regulatory
Commission any more than I'm sure they do, but it just
doesn't seem to me to be efficient to go back and start a
whole new affair. We've got a rulemaking, we've got a
petition. We've been through the public comment period.
If you wanted a -- if the staff of the Nuclear
Regulatory Commission wanted to push that through, all they
got to do is say, boom, final rulemaking, and away it goes.
Now, if the staff of the Nuclear Regulatory
Commission doesn't want to have the petition approved, fine,
then they say they don't want to have it approved and here's
the following reasons and they send me a letter back saying
we've considered it, but we don't want to do it, and too
bad.
DR. KRESS: Well, it seems to me like if NRC has
embarked upon option three, which is risk-informing a great
deal of Part 50, and that they have a priority system on
which regulation they're going to do first and that if this
one fits into that priority system, so that it gets early
attention, and that all they're doing is trying to figure
out what they mean by risk-informing the rule, it seems like
it's appropriate to include it under that process.
MR. CHRISTIE: I have no problem at all.
DR. KRESS: That's the way I read what's going on.
MR. CHRISTIE: The way I read it is they're going
back to square one.
DR. APOSTOLAKIS: We'll ask them this afternoon.
MR. CHRISTIE: Right. Ask them this afternoon.
The things that I have a problem with right now are the bit
about station blackout for the MARK 3's and the ice
condensers. It doesn't make any technical sense to me. And
then where in the world are we with respect to getting a
rulemaking gone?
I think we've got a good rulemaking. I think
we're very close to having complete agreement on a
rulemaking, as far as I can tell.
DR. APOSTOLAKIS: Okay. Thank you very much, Bob.
We will recess until 12:45.
[Whereupon, at 11:47 a.m., the meeting was
recessed, to reconvene at 12:45 p.m., this same day.]. A F T E R N O O N S E S S I O N
[12:47 p.m.]
DR. APOSTOLAKIS: We are back in session. This
afternoon we will discuss the risk-informed revision of 10
CFR Part 50 option three and 10 CFR 50.44.
I understand most of the presentation is on 50.44.
I thought it was to be on option three. I don't know.
I have a number of comments on SECY-00-0086, which
I don't know now how we can transmit to you and when the
committee will have a chance to review that, because this is
a very important document.
At some point, we will have to write a letter, I
suppose. That would be sometime in December, Tom?
MR. KING: I think we're talking about two
letters, probably. We owe the Commission a paper in August,
which is primarily to present our recommendations on 50.44,
but, also, as part of that paper, we're going to provide an
updated framework document, recognizing that this is all
work in progress and things are evolving as we go.
We're also going to present the Commission any
policy issues they have to deal with and we're going to talk
about those today.
I think these are policy issues that aren't
limited to 50.44. These are broader policy issues. It was
50.44 that brought them out.
DR. APOSTOLAKIS: So in July we will have to write
a letter.
MR. KING: So I would like a letter either in July
or, at the latest, I know you don't have an August meeting,
but you have a meeting starting August 30th, I think, your
September meeting, that would probably be the latest for
that August paper.
Then in December, we owe another report to the
Commission and we would probably be asking for a letter on
that one, as well.
DR. APOSTOLAKIS: And that would be on option
three, independent of 50.44.
MR. KING: Well, 50.44 is part of option three,
remember. It's the first test case that we're running
through the framework.
DR. APOSTOLAKIS: But we haven't discussed the
framework, that's my concern.
MR. KING: We had discussed it back in March or
so. We went through the framework. You had given us a
number of comments. We didn't ask for a letter.
DR. APOSTOLAKIS: Without the benefit of a
document, though. We had the viewgraphs, I remember, but
not the document. I mean, this is the first time I see this
document and it's being transmitted to the Commissioners
April 12.
MS. DROUIN: It was transmitted then, but it was
out for public comment. The first of February, we sent it
to the public document room. It was on the web site. So
it's been out there since February 1.
DR. APOSTOLAKIS: Well, sure, but --
MR. KING: Recognize, the April 12 package is not
the final framework. It was a status report and we gave the
Commission what we called a draft framework. It represented
work that was done up to that time and the framework is
evolving as we proceed and we get into these test cases.
So your comments on the framework are certainly --
it's not too late. We certainly are interested in those. I
mean, if you want to give those to us today, fine. If you
want to talk about them, if you want to schedule another
meeting to talk about them, whatever.
DR. APOSTOLAKIS: I don't know how the members
feel.
DR. KRESS: I think it's an extremely important
document and we ought to schedule a meeting and get the full
benefit of comments from as much of the committee as we can,
the subcommittee anyway.
MR. KING: We got comments -- not recently -- a
couple months from NEI on the framework. We're having a
meeting with them tomorrow to talk about their comments on
the framework.
So they continue to come in as time goes on.
DR. KRESS: This is a seminal document. We really
ought to --
DR. APOSTOLAKIS: It's a big thing. We can
decide. I don't know. Mario, do you have any thoughts?
Bill? Bob? Jack? Any comments?
MR. KING: It would be useful to do that, though,
before this August paper goes up. The sooner the better.
DR. KRESS: We'd have to do it with subcommittee
then?
MR. KING: But when?
DR. KRESS: Just have a subcommittee of the whole.
Get all the members here.
DR. APOSTOLAKIS: The problem with full committee
meetings is that you can't really get into detail.
DR. KRESS: You can't get into enough detail for
this document at the full committee. I'd rather have a
subcommittee of the whole and have a full day of it, at
least, maybe even more, if they would agree to it.
MR. KING: We're having our own internal retreat
on the framework document and 50.44 on July 14, as you know.
Even internally we're getting some comments on it.
DR. BONACA: Will you be here the morning of the
11th?
DR. APOSTOLAKIS: I will be here in the morning,
yes, Tuesday morning, the 11th. In fact, the P&P meeting
can be pushed a little bit into the afternoon, or another
way would be to maybe do the P&P in the morning, finish with
it.
DR. BONACA: We can adjust that.
MR. KING: That would be much better for us,
because we have a meeting with NEI in the morning of July
11th.
DR. KRESS: We could cover it pretty well in half
a day, I think.
MR. KING: Half a day would probably be --
DR. APOSTOLAKIS: I'm sorry. What?
MR. KING: A half a day meeting would probably be
enough.
DR. APOSTOLAKIS: Half a day, you know, four to
five hours. I don't think we need more to that.
MR. KING: The afternoon of July 11th is okay.
DR. APOSTOLAKIS: We have to coordinate it with
the Chairman of the committee so that the P&P subcommittee
meeting --
MR. KING: We come to you again on the 12th as a
full committee, but we only have two hours.
DR. APOSTOLAKIS: It's out of the question. We
have to get into it in more detail. I mean, this is one of
the major changes in the regulation.
So let's say until we settle it with Dr. Powers,
that the 11th, which is a week from this coming Tuesday,
right?
MR. KING: Right.
DR. APOSTOLAKIS: We'll try to find a block of
four hours or so.
DR. SHACK: That's Tuesday afternoon.
DR. APOSTOLAKIS: Tuesday afternoon, so that
members can fly down in the morning. The ones who are
members of P&P will have to come Monday night anyway. Does
Noel know that?
MR. MARKLEY: Noel is going to check with Dana
now.
DR. APOSTOLAKIS: Yes, but he should propose that
the P&P be in the morning.
MS. DROUIN: At this meeting, George, are you
looking for more a round tabletop discussion where you would
just be walking through and giving us --
DR. APOSTOLAKIS: I'm sorry, Mary. What did he
just tell us? 1:00 for us.
MR. MARKLEY: 1:00 for us.
DR. APOSTOLAKIS: I'm sorry. Go ahead.
MS. DROUIN: Are you more interested in just
sitting down and going through the report and having more of
a roundtable discussion or us preparing a formal
presentation?
DR. APOSTOLAKIS: Well, you must have presented
this to other people. I don't want you to spend extra time
preparing. I mean, it's always helpful if you guide the
discussion by a set of viewgraphs, but if you have to start
from scratch, no.
MR. KING: We could take previous viewgraphs and
hit the high points.
DR. APOSTOLAKIS: The things that you have used
already, because we can always go page by page.
DR. BONACA: Actually, you have a number of charts
in the report.
MR. KING: Yes.
DR. BONACA: That you can push that out and we can
--
DR. APOSTOLAKIS: But a lot of this stuff I see
for the first time, like the prioritization decision tree.
In fact, we will ask the whole committee to come. This will
be a subcommittee with the full committee present.
MS. DROUIN: I think we ought to give them the
more updated version.
MR. KING: There obviously isn't much time.
MS. DROUIN: George, as Tom had pointed out, this
has been a living document.
DR. APOSTOLAKIS: Exactly.
MS. DROUIN: And we have been receiving comments
and as we have received them, we have been updating it. I
think it would probably help for you to not -- we can get it
to you this afternoon, right away, the more updated version.
DR. APOSTOLAKIS: If I can get it this afternoon,
that's fine with me, because I'm going out of the country
this weekend.
MS. DROUIN: We can give it to you. In fact, I
have one right here, I can get it copied right away.
DR. APOSTOLAKIS: Are there dramatic changes?
Because I've marked this up.
MS. DROUIN: In terms of the basic framework,
those figures, no, but chapter five, which talks about the
implementation, the prioritization and everything, that has
changed quite a bit.
DR. APOSTOLAKIS: So the members who have not read
it have an advantage here.
DR. BONACA: Well, we'll need to see it sometime
next week.
DR. APOSTOLAKIS: Yes. So I think it's a good
idea. Tuesday.
MS. DROUIN: I can give it to you right now. I
have it right here in front of me.
DR. APOSTOLAKIS: Tuesday, I hope Dana will agree.
MR. KING: So we'll plan July 11th, in the
afternoon then.
DR. APOSTOLAKIS: Let's plan on that, until we
hear from Dr. Powers.
MR. KING: And you'll probably get -- maybe touch
on some of the framework issues today as we go through
50.44.
DR. APOSTOLAKIS: Of course.
MR. KING: All right. For the record, we have put
on the front slide the primary participants who have been
working on the 50.44 issue. They're not all at the table.
With me at the table, for the record, my name is
Tom King, from the Office of Research; John Lehner, from
Brookhaven National Laboratory; Mary Drouin, from the
Research staff; Trevor Pratt, from Brookhaven; and, Allen
Camp, from Sandia.
As I said, we're not asking for a letter at this
point. This is a status report. We're going to focus on
50.44 and we're going to touch on some of the potential
issues that will probably be in the paper that goes up to
the Commission in August.
Some are policy, some are technical, but even the
technical ones even have some policy nature.
So any thoughts you folks have on issues would be
very useful to get today, so we can start to formulate them
for the paper.
Stakeholder input. One question we had gotten was
that you were interested in talking about the January 19
letter we got from Joe Colvin of NEI. It basically came in
and reported the results of a survey that NEI had taken of
the industry.
It was an attempt to give us some information on
their priorities and potential cost savings associated with
risk-informed changes they'd like to see, and that would
help us prioritize our activities.
We did get the letter. We basically found it
matched up pretty well with the priorities we had already
come to from our own thinking and previous discussions among
ourselves and with industry folks.
We had also gotten a letter dated April 18 from
Steve Floyd to myself, with a lot of comments on the
framework document. If you don't have that, I've got a copy
here you can have. You do have it?
DR. APOSTOLAKIS: Yes.
MR. KING: Okay. And as I said, tomorrow we're
meeting with NEI on the comments in that letter.
We had responded to the Colvin letter. It was
just a short response thanking them for their input and
recognizing that the main points in their letter we were
accommodating as part of our framework and option three
work.
That's all I really intended to say about the
January 19 letter. I don't know if you have any other
specific points you want to get into.
DR. KRESS: I had, I guess, a question. The 19th
letter had some associated cost-benefit savings that NEI had
gotten from their survey.
MR. KING: Yes.
DR. KRESS: Do you have any plans for using those
numbers in any way in this process?
MR. KING: I think those numbers will certainly
help us in trying to prioritize our work. If we see
regulations that look like they would have a large
cost-benefit impact associated with them, they may go more
toward the top of the list of things we work on first.
DR. KRESS: But they won't be used -- I think
prioritization --
MR. KING: That's not the only factor.
DR. KRESS: Prioritization is a good thing to use
them for, but I was concerned that you may have some sort of
an inverse backfit part of your system that has as
cost-benefit type of --
MR. KING: We're going to get to that issue when
we get to the slides.
DR. KRESS: You wouldn't use those numbers for
that, though.
MR. KING: If we do some sort of reverse backfit
test, those numbers could be useful. But whether we do one
or not is an issue at this point. I was going to talk about
that when we get to another slide.
DR. KRESS: I'll wait.
MR. KING: In terms of prioritization, I mean,
clearly safety is the first factor.
DR. KRESS: Of course.
MR. KING: If we go through a risk-informed look
at something and there's a safety issue that really goes to
the to of the list. But then there's other factors to sort
out the other things, and cost is one of them.
The other thing I want to mention, maybe you're
not aware of, is some members of the Research staff had a
meeting with Commonwealth Edison a week or so ago, June
14th, actually, where Commonwealth Edison gave out quite a
detailed list of changes that they feel could be made,
risk-informed changes to the regulations, and cost savings
associated with them.
They went into more detail than the Joe Colvin
January 19 letter. If you are interested in that list, I've
got a copy of it here. You might find it interesting to see
what they have to say.
DR. UHRIG: I don't think we have it.
MR. MARKLEY: What we have is a June 7 NEI letter.
DR. BONACA: That's right.
MR. MARKLEY: That's the latest thing you have.
MR. KING: This is the results of the June 14
meeting, but it's publicly available. This is an extra
copy, if you want to take it.
With that, I'm going to turn it over to Mary to
talk about our approach and the alternatives we've come up
with on 50.44.
MS. DROUIN: We weren't planning on getting into
any of the details of the framework, but we wanted to talk a
little bit about the framework, because it does establish
our approach and how we came up with our options.
We have developed a framework and in developing
that framework, what we tried to do was blend the principles
from Regulatory Guide 1.174 with the cornerstones that are
outlined in the oversight program for safe nuclear power
plant operation.
So what we tried to do there was balance an
accident prevention and accident mitigation to achieve a
defense-in-depth approach in building the framework.
The way we went about trying to achieve this
defense-in-depth balance is that we defined four strategies
in the framework and these four strategies were looking at
limiting your initiating events, or limiting your core
damage accidents, or limiting your radionuclide releases, or
limiting your public health effects.
And taking these strategies and this accident
prevention and mitigation, we then came up with quantitative
guidelines for these. We only developed these quantitative
guidelines to help us frame the options, such that when we
come up with a risk-informed option, we wanted to make sure
the option was neither too conservative, such that we were
imposing undue conservatism or undue burden; at the same
time, we wanted to make sure an option is not too relaxed.
So whereas we don't expect to ever see this
quantitative guidelines in a regulation, they're just
helping us put it in the ballpark, such that we have
achieved these strategies in maintaining our
defense-in-depth.
DR. KRESS: Might those numbers appear in a reg
guide or somewhere else?
MS. DROUIN: They could appear in a reg guide for
-- and I'm going to get to that in one of our options on
50.44.
DR. KRESS: At the moment, those numbers are
intended to be means.
MS. DROUIN: Yes.
DR. APOSTOLAKIS: I have two comments already on
this. I don't think that calling it balanced high level
defense-in-depth really represents what you're doing and you
say that also in the document, the approach recommended by
the ACRS and adopted herein is a structure of this high
level defense-in-depth approach.
Well, the ACRS recommended the preliminary
framework that also addressed what to do at lower levels,
and you are very silent on this in this chapter two, to the
point where one wonders have you rejected this or what do
you plan to do at lower levels.
But then you go to chapter four and on page 4-3,
it says decisions regarding lower level defense-in-depth in
the form of redundancy or diversity are generally well
suited to this type of analysis, which is a PRA.
I mean, you just said it was a PRA, that's what it
refers to. So I was wondering why you focus so much on high
level defense-in-depth and you don't actually say this is
defense-in-depth at the high level, rationalist at the lower
level, except when the uncertainties are such that
defense-in-depth must be invoked at lower levels, as well,
as you strongly imply later that you're going to do.
I mean, if I read chapter two, the only thing you
are telling me is that at the high level, you are
structuralist, and nothing on anything else. But later on
in the implementation, you say, no, no, no, we're going to
use PRA at lower levels.
I'm just wondering why that was --
MS. DROUIN: Are you disagreeing with what's later
on in the --
DR. APOSTOLAKIS: I am not disagreeing. I'm just
wondering why you focus so much on the high level
defense-in-depth and even in your title here says balanced
high level. What happens at lower levels?
MS. DROUIN: I think that is one of the comments
from other people and from ourselves that we have noticed in
the document is this inconsistency of things written in one
part of the report and the other.
That's not meant to be.
DR. APOSTOLAKIS: No, I understand. I'm just
making the comment. When I read it, I was wondering,
because you talk about structuralist and rationalist, and
they say we're going to apply structuralist at the high
level.
So I said, well, gee, on the next page they're
going to tell me why rationalist at lower levels is a crazy
idea, because they don't want to use it. But you are
completely silent.
But then when it comes to chapter four, you are
speaking about it matter of factly, yes, and we're going to
do PRA evaluation.
So I think it needs tightening up.
MS. DROUIN: Absolutely.
DR. APOSTOLAKIS: I don't disagree with what you
say.
DR. KRESS: You're not opposed to this high level.
DR. APOSTOLAKIS: I just don't think this is what
they're doing. This is part of what they're doing.
DR. KRESS: It's part of what they're doing, yes.
MS. DROUIN: Yes.
DR. KRESS: But I would not have called this the
structuralist approach.
DR. APOSTOLAKIS: No. It's the preliminary
proposal.
DR. KRESS: I would call it the rationalist. But
I would have called that a rationalist approach there.
DR. APOSTOLAKIS: Well, because at the high level
we impose the structuralist, without any reason. What they
call four strategies, that's what we do, too. That's why
it's preliminary.
DR. KRESS: I still disagree. This is
rationalist.
DR. APOSTOLAKIS: Because of the uncertainties at
that level, but I think that's too subtle for most people.
Anyway, your name is on the paper. You can't disagree.
DR. KRESS: It's too late to disagree.
DR. APOSTOLAKIS: It's too late to disagree. And
the other thing is, which is related to what you said, I'm
just limiting my comments on what you said, which brought --
you really go out of your way in this document to tell
people that one quantitative risk numbers will not appear in
the regulations and you say that so many times, that there
must be a reason behind it.
So what is that reason?
MR. KING: That makes it risk-based.
MS. DROUIN: It makes it risk-based.
DR. APOSTOLAKIS: If you use one number, it makes
it risk-based?
MR. KING: Put the number in the regulation.
DR. APOSTOLAKIS: The way you put it here, Tom, is
that nothing that smells of frequencies will appear
anywhere. It's one thing to base everything on the QHOs and
quite another to have such sweeping statements that the
regulations will be deterministic.
And the way I understood it, then, PRA will be
used to rationalize why you go this way and that way. But
it seems to me that in some instances, you may have to use
unavailabilities or something.
You are saying no, no -- that's a no-no. Would
that make it risk-based if you use the little number here
and there?
MR. KING: If we start putting risk numbers,
whether they're core damage frequencies or reliability
numbers or something in the regulations, our view is, yes,
that makes it risk-based, because then that becomes the sole
factor on which you make your decision.
DR. APOSTOLAKIS: No, because the oversight
process uses performance indicators and explains to us that
--
MR. KING: But they're not in the regulations.
We're talking about the regulations. Reg guides are a
different story. SRPs are a different story.
DR. APOSTOLAKIS: Reg guides are not regulations.
MR. KING: Reg guides are not regulation. Reg
guides are one way to meet the regulations, one acceptable
way.
DR. APOSTOLAKIS: It's just that you say it so
many times in such a definitive way, that I thought there
was something behind it.
MR. KING: Maybe we over-emphasized a bit.
DR. APOSTOLAKIS: Yes, I think you did.
MR. KING: But the idea is --
DR. APOSTOLAKIS: Heaven forbid if we become
risk-based, a quarter of a page.
DR. SHACK: They keep getting advice from advisory
committees to put numbers in, George.
DR. APOSTOLAKIS: Say it again.
DR. SHACK: They keep getting advice from some of
their advisory committees to put numbers in, letters.
DR. KRESS: They continue to reject it.
DR. APOSTOLAKIS: Another thing is I don't know if
-- it looks like the risk-based is really something that the
agency must avoid at all costs. I thought risk-informed was
a good terminology that really reflected reality, but now it
has come to the point where people say we're not going to do
this because if we do, it's risk-based.
In other words, it has become something to avoid
at all costs.
DR. KRESS: I guess I would disagree that having
actual risk numbers as targets makes it risk-based. If you
do all the other things, like defense-in-depth and deal with
uncertainties and appropriate margins, also, then I think
you can have numbers in there and call it risk-informed.
DR. APOSTOLAKIS: I think so, too. But anyway, if
you tone down the document here. It appears like you're so
sensitive to that.
MR. KING: I mean, we don't want it so slanted
that -- we're sensitive.
DR. APOSTOLAKIS: I mean, we are sensitive people.
Allen, you wanted to say something a half an hour ago.
MR. CAMP: I forgot what it was.
DR. KRESS: We talked you out of it.
DR. SHACK: One comment we made before was that
these were PWR numbers and they're not really BWR numbers.
You end up with LERF about the same range, but at least
looking at the IPEs, these look like sort of unrealistic
expectations for conditional containment probabilities for
BWRs.
MR. KING: They are really numbers that come out
of the Commission's 1990 SRM that told us how to implement
the safety goal, that laid out the ten-to-the-minus-four CDF
and the LERF we derived working backwards from the QHO.
You're right, we haven't tried to distinguish between B's
and P's and that's certainly an issue in implementing it
that we're going to have to deal with.
But they're intended to be a generic set for both.
DR. APOSTOLAKIS: One last comment, because I
think it's relevant to what's coming.
The document 00-0086, well, gee, you know, today
we have 00-02, now we have 00-0086.
DR. KRESS: 007.
DR. APOSTOLAKIS: Yes. A lot of zeroes. This
document proposes a framework and then it goes on to propose
some target numbers for containment, the right frequencies,
and so on.
Now, this is intended to be used by the regulator,
correct?
MS. DROUIN: Yes.
DR. APOSTOLAKIS: And I was wondering -- and,
again, I don't have a position on this, but I think it's
something that needs to be aired.
The QHOs were always intended to be goals, not
measures of adequate protection or inadequate protection.
In other words, you can exceed them and you can still
provide adequate protection.
Is it really appropriate for such fundamental
documents to use the QHOs, something that is a goal and we
know already 19 PWR units are above it? Not the QHOs, but I
mean the lower CDF.
Is it appropriate to do that, Tom? I don't know.
Or should we looking for something else?
DR. KRESS: George, I would prefer we not even
discuss that subject anymore, because I like the idea of
using those goals as guidance to guide the regulations, even
though they may or may not represent adequate protection, as
we know it, in terms of real numbers.
Those are pretty good goals and I see very little
wrong with them. They're accepted. And I think as a
guidance, you're not going to -- you're not going to say you
must meet these numbers. That's why they're saying they're
not going to put the numbers, partly why they're there, but
they're going to use it to guide how they get the
regulations and the regulations are going to be crafted in
such a way that they won't exactly meet them.
Some plants will do better and some plants may not
do as good. So I think it's a nice target to set when
they're going to want to gauge how to write the regulations.
It avoids this issue of quantifying adequate protection and
trying to put numbers in the thing.
So I'm comfortable with it now and I kind of want
to avoid even mentioning it anymore. Go on and let's do it,
because it does raise issues of are we ratcheting and are we
doing --
DR. APOSTOLAKIS: Well, that's exactly my concern.
But if we start using them in the regulations, before you
know it, they will become measures of adequate protection.
DR. KRESS: That's what I would really -- I have a
hidden agenda. That's what I'd really like to have happen.
DR. APOSTOLAKIS: Well, my agenda is out in the
open and I really don't think that would be appropriate.
For example, I don't understand -- you just said
that we can use those to write regulations and then we'll
say, you know, gee, some of you guys will not meet it. I
don't understand that.
I mean, if we write the regulations, then --
DR. KRESS: They'll meet the regulations, but they
may not exactly meet those target values for the frequencies
and the CDFs and things like that. They'll be close enough
-- if you do the regulations, it's good enough, but there
won't be a direct one-to-one link between the --
DR. APOSTOLAKIS: There won't be a direct
one-to-one link, but if we follow the framework and we have
numbers for core damage frequency, conditional probability
of containment failure and so on, and we write the
regulations that way, then eventually they will meet those,
because the regulations will be a coherent code.
DR. KRESS: I say good.
DR. APOSTOLAKIS: I realize that, but the question
is whether you want this to be a measure of adequate
protection.
MR. KING: No. No. The issue you're talking
about is going to have to be discussed in the August paper
and the Commission is going to have to buy into using the
safety goals as the measure of how far we want to go in
risk-informing things.
DR. APOSTOLAKIS: I think that we are using the
safety goals because that is what's available, correct?
It's a number that's available.
MR. KING: It's what is available. It avoids
having to deal with the question of defining adequate
protection, which, in my view, isn't necessary for
risk-informing.
DR. KRESS: And it gives you an idea of what a
proper balance might be based on tradition.
MR. KING: And it reflects the Commission's --
remember, the safety goal policy statement is a statement of
the Commission's expectations of the safety they'd like to
see achieved.
DR. KRESS: It has a lot to --
MR. KING: If that's what they want to see
achieved, it would seem reasonable to me that we proceed
down a path that lays out a framework to achieve that. And
maybe it won't pan out in all cases for cost-benefit reasons
or something, but why not aspire to that?
DR. APOSTOLAKIS: I can see this ratcheting up the
regulations down the line.
MR. KING: That's another issue.
DR. APOSTOLAKIS: So I really think -- and I'm
glad you said that you will raise the flag to the Commission
to think about it.
DR. KRESS: But risk-informed regulations are
going to be voluntary, right?
DR. APOSTOLAKIS: Yes, that's right. Okay.
DR. SHACK: And the proposed rule will have to
meet a backfit rule.
DR. KRESS: I think it's entirely appropriate that
they use these.
DR. APOSTOLAKIS: This is something that I think
we should discuss at the subcommittee meeting.
DR. KRESS: Yes, we ought to.
DR. APOSTOLAKIS: Which I was informed will be at
1:00 on Tuesday, July 11th.
DR. KRESS: Okay. And you put that on the
calendar.
DR. APOSTOLAKIS: That will certainly be on the
calendar and see how we can approach it.
DR. KRESS: Sure.
DR. APOSTOLAKIS: Because it may be that you put a
few qualifiers there and then the concern goes away. But I
don't think we should just matter of factly pick up those
numbers and just run with them and starting writing the
regulations. I just don't think so.
MR. KING: It's clearly a policy issue, in my
view.
DR. APOSTOLAKIS: Yes. It's a policy issue and
before the decision is made, I think the decision-makers
should be informed what the concerns are.
MR. KING: Okay.
DR. APOSTOLAKIS: Of the various agendas we have.
Maybe a three-vision approach may be useful.
MR. KING: Shades of gray, maybe.
DR. APOSTOLAKIS: Shades of gray are working very
well. See, if you look at the ASME thing, I think now the
categories make much more sense to me.
MS. DROUIN: Are you ready?
DR. SHACK: Category one plants and category two
plants.
DR. APOSTOLAKIS: Yes.
MS. DROUIN: In looking at our approach, there's
three major steps. The first one, of course, is selecting
what regulation to risk-inform out of 10 CFR 50.
What we have done to date is that we have
performed a core screening and we're going through our
prioritization. The core screening, first, just looked at
whether or not the regulation dealt with accident prevention
and accident mitigation and if it did, then it was a
candidate for risk-informing regulation, and then we started
going through the prioritization.
And in going through the prioritization, the first
thing we would look at once it was a candidate, is it even
warranted to risk-inform the regulation. What we mean by
that is in looking at the regulation, if you risk-informed
it, were you going to be able to gain any safety benefit,
was there any conservatism in that regulation, was there any
excess burden.
And if you weren't going to gain any safety
benefit and there wasn't any conservatism and there wasn't
any excess burden, then it would be eliminated further.
Then in further prioritization, the next thing
that we would look at is what was the safety significance of
that regulation, and then looking at what the resources it
would take to risk-inform and then also looking at the
potential for reducing any unnecessary burden.
And taking these factors into account, 50.44 fell
out as a very high priority and that was the one that we
identified as the first in what we're using as our test case
against the framework.
DR. APOSTOLAKIS: You didn't know that, Bob?
MR. CHRISTIE: Excuse me?
DR. APOSTOLAKIS: This morning you said you didn't
know what the staff was doing. They are telling us this is
the test case. Is that consistent with what you said this
morning?
MR. CHRISTIE: They're testing against the
framework.
MR. MARKLEY: Microphone, please.
MR. CHRISTIE: This is Bob Christie, Performance
Technology. The staff, in option three, is testing the
framework with respect to 50.44. In my comments to you on
March 1st, we vehemently disagreed with the framework that
has been outlined in the February meeting to us.
The framework has changed. We don't see that the
changes have been any for the better and they can go on
having this very complicated framework document that they
can test any regulation about to infinity and that will be
their objective.
Our objective is to make the regulations more
effective and efficient and we don't need this framework and
testing out 50.44, in the petition we submitted or I
submitted or any submits, against this framework seems to us
to be kind of an academic exercise that doesn't move
anything towards decisions to make the regulations more
effective and efficient.
Just flat, hey, we're now shooting for how safe is
safe enough, is adequate protection, just blows my mind. It
just absolutely is crazy.
If that's what we're fighting for, you know, you talk about
this being voluntary, you want to say how safe is safe
enough is now adequate protection, you just carry on with
voluntary efforts, if that's the framework and that's the
decision criteria.
MR. KING: That's not what we said. We're not
equating how safe is safe enough to adequate protection.
MR. CHRISTIE: Again, this is Bob Christie. I
heard that we are going to aspire at writing the regulations
to achieve the levels as set forth in the safety goals,
which are, as far as I can tell, in the June 11 or whatever,
the June 1990 memorandum was, from the Commissioners to the
staff, was very clear that the safety goals were how safe is
safe enough, the point at which even backfit was not to be
considered.
Aspiring to them and using those as the guides and
the criteria for the regulation, to me, look like you're
moving the rules to how safe is safe enough.
DR. APOSTOLAKIS: And this is certainly something
that we'll discuss on July 11th. Anyway, thanks for the
comment.
MS. DROUIN: In developing our options, we took
two different paths to come up with the options. The first
was to look at the current requirements and to risk-inform
the requirements. The other path to come up with options
was to start with a blank piece of paper, look at the threat
or the concern and if you started with a blank piece of
paper, what requirements would you come up with, and then
that would give us the pool of options and then based on
those options, we would come up with alternatives for a
risk-informed 50.44.
In going down the path of looking at the current
requirements, what we would do and what we have been doing
on 50.44 is to go back and look at those requirements and
look at what was the technical bases of those requirements,
look to see how those requirements were implemented by the
licensees, identify any related regulations in the
implementing documents, because one of the biggest things
that we have learned is you can't take these things in
isolation.
A lot of the problems that you have with a
particular regulation is not so much in the regulation
itself, but it comes out perhaps in a related regulation or
in the implementing documents.
And then start doing a risk evaluation of that and
coming up with options. We'll get through this more as we
get into 50.44.
Once we have identified the alternatives, then I
do an evaluation to try and prioritize those. In this
particular prioritization, what we would do is look at both
the impact to the NRC and the impact to the licensees.
In looking at the NRC, we would look at such
things as is it going to require a rule change, what would
be the impact of doing this on other regulations and
implementing documents, would we have to modify them, would
we need to create perhaps some new regulatory guides, what
would be the extent of regulatory analysis that we would
need to do.
If the alternative would require some submittal
from the licensee, what would be the extent of NRC review,
what would be the impact on inspection. These are just some
of the factors that we would take into account in trying to
prioritize the regulation.
Also, of course, goes in there what the safety
benefit would be.
In looking at the licensee and the impact on the
licensee, what would be the need for perhaps new or make
modifications to the current design in place, looking at the
need for analysis on the licensee's part, the impact on
their maintenance and inspection activities, impact on
technical specifications, impact on procedures and training.
And here, again, are just some examples of the
things that we would be looking at.
Moving on. I'm just going to quickly go through
it, because hopefully we'll get, after this slide, right
into 50.44, how this ties explicitly back to the framework
and how we've used the framework to come up with our
risk-informed options.
First, starting with what is the concern that
we're dealing with and how does this concern tie into the
four strategies that are outlined in the framework.
Is it dealing with accident prevention and
mitigation and within those two things, is it dealing with
just limiting the initiating events or is it dealing with
limiting the accident sequences or is it dealing with
limiting your radionuclide releases or is it dealing with
the health effects.
For example, on 50.44, the fact that we're dealing
with the combustible gases, the strategy that is of concern,
that it's tying directly to into the framework, is our third
strategy of limiting your radionuclide releases, trying to
contain your conditional containment failure probability.
And then identifying that concern, the relative
importance of that concern against the quantitative
guidelines. If, for example, and this is just hypothetical,
if you look at this and you see from your risk insights that
your conditional containment failure probability from this
concern is -- say it's extremely high, close to unity,
that's identifying that this is a concern, this is something
that the regulations ought to be dealing with.
If you are on the other extreme and you're getting
something that's, making up a fictitious number,
1E-to-the-minus-four for your conditional containment
failure probability, then you would question why are we
regulating this.
DR. KRESS: Do you mean the contribution of that
particular rule to the conditional containment failure
probability?
MS. DROUIN: The contribution of that concern.
DR. KRESS: That concern, I mean. The concern you
said here was containment failure.
MS. DROUIN: The concern is hydrogen combustion.
DR. KRESS: The concern is hydrogen combustion.
MS. DROUIN: So if I look at, if I'm going through
and I'm looking at my risk insights --
DR. KRESS: Now, will you do this on a plant type
by plant type basis? Like you will look at it for -- I
mean, will the rule apply to all plants across the board or
would you look at the ice condenser separately from --
MS. DROUIN: Both, both.
DR. KRESS: -- BWRs?
MS. DROUIN: Both.
MR. KING: You will see the alternatives. Some
are broader that apply generally and some are the specific
like the current rule, but modified to reflect risk
insights.
DR. KRESS: So you might have this rule written
differently for ice condensers as opposed to large drys.
MS. DROUIN: Absolutely.
DR. KRESS: Okay.
MS. DROUIN: So you would look at the specific
containment types, but you would also look at it
generically.
And then once you've identified whether or not
this is a concern that should be in the regulations, then in
developing the options, we would look and make sure that a
single class doesn't contribute more than ten percent to
that guideline.
DR. KRESS: Now, that's a very interesting number.
DR. APOSTOLAKIS: That's a Sizewell guide.
DR. KRESS: It's the rule of ten, which is a nice
rule to use when you have to pick something out of the air,
which is basically what you have to do. It's a policy type
thing.
But I guess I wanted to ask, could you have an
additional line there and say "or" more than ten percent to
the uncertainty?
MS. DROUIN: In doing that, you would have to
account for the uncertainty in there.
DR. APOSTOLAKIS: To the standard deviation.
DR. KRESS: Or to the standard deviation or
something like that.
MS. DROUIN: Yes.
DR. KRESS: Could you have an additional -- that
would help me a little, because it ties into my concept of
what defense-in-depth is related to uncertainties.
DR. APOSTOLAKIS: I have a number of comments on
this. First of all, I don't know that you can separate the
variance from the mean, because if you reduce -- you see,
these are wide distributors.
If you reduce the high tail, the mean also moves.
DR. KRESS: Sometimes.
DR. APOSTOLAKIS: So clearly it's something we
have to understand.
DR. KRESS: But you need to understand the point
with the uncertainties, too.
DR. APOSTOLAKIS: The other point I want to make
is this is really a defense-in-depth structuralist kind of
approach, because you're just declaring it ten percent. I'm
wondering why.
I agree with what you said earlier that you will
have defense-in-depth at the top level, but what is it -- or
maybe it's rationalist view here.
DR. KRESS: It's a rationalist view, in my
opinion.
DR. APOSTOLAKIS: Realize that the uncertainties
are very large at the accident sequence level and you want
to take a defense-in-depth measure to handle those, and that
is that no single class should contribute more than ten
percent.
You could rationalize it that way.
DR. KRESS: I'm not sure I know exactly what they
mean by accident class here.
DR. APOSTOLAKIS: I think they mean the initiator.
DR. KRESS: The frequency range of initiators.
DR. APOSTOLAKIS: Yes. In other words, I think
they define it here.
DR. KRESS: It could be different kinds of
sequences.
DR. APOSTOLAKIS: There is a definition here that
these must have --
DR. KRESS: But what you do when you do that is --
DR. APOSTOLAKIS: -- similar physical
characteristics.
DR. KRESS: -- you lump into an accident class
different kinds of sequences, which bothers me, to some
extent.
DR. APOSTOLAKIS: Like small LOCA will be one
class.
DR. KRESS: No, I don't think so. Those
initiators of frequencies within certain ranges are a class.
DR. APOSTOLAKIS: No. That's not --
DR. KRESS: That's not what you mean.
DR. APOSTOLAKIS: No.
MR. KING: No.
DR. KRESS: You actually mean the traditional
sense of --
DR. APOSTOLAKIS: Small LOCA.
DR. KRESS: Okay. Then I'm not bothered by it.
DR. APOSTOLAKIS: Physical and chemical
characteristics.
DR. KRESS: Okay. I'm not bothered by it then.
DR. APOSTOLAKIS: These are not the categories
that they have in the framework.
DR. KRESS: They're not related to these
categories. Okay.
DR. APOSTOLAKIS: Infrequent events.
MS. DROUIN: That's right.
DR. APOSTOLAKIS: But, again, maybe you want to
think a little bit about it and the rationalization here of
the framework.
MR. KING: Yes.
DR. APOSTOLAKIS: Also, it appears -- I think it
should be given more prominence. I think all the
defense-in-depth measures you are taking in this framework
should be collected in one place.
DR. KRESS: I do, too.
DR. APOSTOLAKIS: And justified.
DR. KRESS: And this is, in my mind, a
defense-in-depth --
DR. APOSTOLAKIS: I have an agenda, too, by the
way.
DR. KRESS: -- issue there.
DR. APOSTOLAKIS: If you justify them in terms of
uncertainty, the whole document is rationalist.
DR. KRESS: I agree.
DR. APOSTOLAKIS: And I think this clearly will be
justified on the basis of uncertainty.
DR. KRESS: Absolutely.
DR. APOSTOLAKIS: You're talking about things that
are so uncertain.
MR. KING: The Commission asked us to come back
and present to them what is our definition of
defense-in-depth and collecting all of this in one place, we
are going to have to do that. You'll see it show up on the
issues slide as something we're going to have to lay out so
that they don't have to search for it here and there in the
document.
DR. APOSTOLAKIS: Also, you really don't -- this
is too important, it seems to me, to talk about it matter of
factly somewhere there.
But I think you can clearly justify just about all
the defense-in-depth measures you have here using the
arguments based on uncertainty, even the high level.
DR. KRESS: I would attempt to do that.
DR. APOSTOLAKIS: And that would be a significant
step over the rational --
DR. KRESS: It would be a wonderful step, George.
DR. APOSTOLAKIS: I knew you would agree.
DR. KRESS: Yes. Okay.
MS. DROUIN: Okay. Now, we're going to get
explicitly into 50.44. When you just look at 50.44 itself
and not any related document, any related regulation or
related regulatory guide or something and just look at the
specific requirements, what I have here is that there are
both analytical requirements and what I call physical
requirements in 50.44.
When you look at the analytical requirements, it's
telling you to deal with a postulated LOCA. For some
containment types, you go to a degraded core accident.
It specifies the combustible gas. It's just
hydrogen, and the source is from the fuel cladding
oxidation. The amount, there's two different amounts you
have to deal with, depending on the containment type. I've
just quickly abbreviated here. One is a five percent versus
a 75 percent metal-water reaction.
When you get into the physical requirements, what
I call physical requirements, there's six of them. You have
to measure your hydrogen concentration, ensure your mixed
atmosphere, control your combustible gas concentrations, and
those are applying across all your LWRs.
The last three, inerting your MARK 1 and 2 containments,
installing the high point vents, that's for all light water
reactors, and installing your hydrogen control system, your
igniters, for your MARK 3's and your ice condensers.
So at a high level, those are the requirements,
the specific technical requirements.
DR. APOSTOLAKIS: When was this rule passed?
MS. DROUIN: There were three stages. You had the
original, then you had a 1981 amendment, and then you had a
1985 amendment.
DR. APOSTOLAKIS: The original is from?
MS. DROUIN: 1979. That's right, 1979.
DR. APOSTOLAKIS: So it was a TMI type.
MS. DROUIN: Right. The 1981 --
DR. APOSTOLAKIS: Oh, just before.
MS. DROUIN: Right. And then the 1981 was a TMI
update, response to TMI.
DR. KRESS: Are the requirements, either in this
particular regulation or in some other?
MS. DROUIN: No. These are --
DR. KRESS: These are in .44.
MS. DROUIN: -- specific in 50.44.
DR. KRESS: Are there requirements elsewhere --
MS. DROUIN: I'm going to get to that.
DR. KRESS: -- that ask for purge and vent
capability?
MS. DROUIN: I'm sorry. Purge and vent is part of
the control of combustible gas concentration. You need to
do the recombiners or the purge and vent.
DR. KRESS: Or the purge and vent.
MS. DROUIN: Yes.
MR. KING: The rule doesn't say have recombiners.
It just says be able to control post-LOCA control and some
plants have chosen to do the purge event.
DR. KRESS: Okay.
MS. DROUIN: Okay.
DR. KRESS: But that's part of this rule here.
MR. KING: Yes.
MS. DROUIN: Yes. When you look at how the
licensees have complied with 50.44, what I've noted on the
left side are just the physical requirements, and when you
look at the predominant means of compliance, you see some
difference between what you saw in the previous slide and
this slide.
For example, the physical requirement was just to
measure hydrogen concentration. That's all 50.44 required
you to do. The way licensees have complied with that is to
install safety-grade continuous hydrogen monitors.
And as you go down, you'll see the same type of
thing, against some of those requirements, that it doesn't
match up directly to 50.44, and there's reasons for that and
that's where we get into why you cannot look at a regulation
in isolation.
You have to see all the tentacles and look below
the surface. I haven't listed them all here. It's quite
extensive. I've only pulled out three just for an example.
One regulation that's tightly tied to 50.44 is
Appendix E to Part 50, the emergency planning and
preparedness for production utilization facilities. This
one is requiring your continuous hydrogen monitoring for
your emergency response data system.
When you go to 50.46(b), it's specifying your
maximum hydrogen generation and postulated LOCAs for the
purpose of complying with your ECCS acceptance criteria.
That's getting into the five percent.
When you look at Reg Guide 1.97, that's what is
imposing the safety grade. So, again, I have just listed
three of them here, but there's a lot of other regulations
that are tied to this, 50.34 is another one. There's other
regulatory guides.
So as we talk about risk-informing 50.44, we're
also talking about perhaps having to change other
regulations and other documents if you want to receive the
complete benefit.
DR. APOSTOLAKIS: That's a purely administrative
issue. It's not that these other regulations bring some
other aspect of the accident or some other accident depends
on this that we have to deal with. It's just
administrative.
I mean, somebody decided that hydrogen control is
important and then that thought is reflected in a number of
regulations.
Is that a correct statement?
MS. DROUIN: In a simplistic answer, yes, but not
always necessarily so, because it might be in another
regulation for something totally different.
DR. APOSTOLAKIS: In a different context.
MS. DROUIN: Yes.
DR. APOSTOLAKIS: But in this context, the three
examples you gave us, it seems to me, they all stem from the
fact that somebody decided this is important and now it's
reflected in emergency planning.
MS. DROUIN: Right.
DR. APOSTOLAKIS: Core cooling design.
MR. SIEBER: Well, 50.46(b), that's an input
assumption to the calculation that establishes the final
acceptance criteria.
MS. DROUIN: Right.
MR. SIEBER: So that one is different than the
other tow. The other two, to me, seem to be administrative.
Somebody here in White Flint wants to know what your
hydrogen is during an accident. That's why it's on ERDS.
And it's in Reg Guide 1.97 because it's in ERDS,
part of emergency planning, and because the rule existed in
the first place, 50.44.
So to me, 50.46(b) is different because then you
have to recalculate to see if you continue to comply with
the final acceptance criteria under Appendix K.
DR. APOSTOLAKIS: There is a technical reason for
50.46(b) in terms of the cladding integrity, coolable
geometry, actually.
DR. BONACA: I think what you're trying to say is
that in some cases, it may not be only a threat of issue.
There is some other type of technical reasons for having the
requirement. Is it true?
MS. DROUIN: Yes.
DR. APOSTOLAKIS: Yes.
MS. DROUIN: Now, when you start looking at going
back and trying to pull your insights, your risk insights
out to see what risk-informed 50.44 or how would you create
a risk-informed regulation that deals with combustible
gases.
When you start looking at your PRAs and you start
looking at your core damage and your core melt accidents,
the first thing that comes out is that the combustible gases
that can challenge your containment integrity are not
limited to hydrogen.
You have both hydrogen and your carbon monoxide
that you need to deal with and also the sources for these
are not just limited to your fuel cladding oxidation. You
also need to take into account your core-crete interaction.
One thing I might point out here is that in terms
of your core-crete interaction, that is highly a function of
what concrete you use. If you're using basalt concrete,
then you aren't getting your carbon monoxide generation.
Also, you're generating these combustible gases,
both in the early stages of the accident and in the late
stages.
So in dealing with trying to control your gases,
you have to look at the whole timeframe. You can't just
limit yourself to the early parts of the accident.
When we start going through the history of our
PRAs and the insights coming from the PRAs, starting with
WASH-1400, is the biggest insight that came out of there, of
course, is that LOCAs are not the only thing you have to
deal with.
You have other accidents that are contributing and
you're getting hydrogen generation, you're getting
combustible gases from these others, and when you
particularly look at WASH-1400, it did predict a fairly high
conditional containment failure probability from hydrogen
combustion.
Even though it wasn't the dominant contributor, it
was a dominant one.
You then had the Three Mile Island accident, which
generated the start of the severe accident research program.
Primarily what this program did was confirm the importance
of your hydrogen, your hydrogen combustion, and the way
that, when you look at the first -- the 1981 amendment and
the 1985 amendment and the things that were put into place
to control these, that these were the right measures in
dealing with it.
When we move on to --
DR. APOSTOLAKIS: Now, has anyone questioned these
findings from the industry? This is all NUREGs and
NRC-sponsored projects, but I'm sure the industry has done
work.
MS. DROUIN: We're going to get into some industry
stuff here, too, on the next one.
DR. APOSTOLAKIS: You will. Okay.
MS. DROUIN: I couldn't fit it all on one slide.
DR. APOSTOLAKIS: So it just happened randomly
there.
MS. DROUIN: Now I'm going chronologically. The
next big risk study that came out was NUREG-1150. It pretty
much still confirmed the same thing. You had other
accidents that were contributing to your core damage.
Hydrogen combustion was a dominant contributor and
that the new thing was that hydrogen combustion was not a
challenge to your large volume containments.
MR. SIEBER: That's based on the assumption that
you use ultimate strength as opposed to design strength.
MS. DROUIN: Yes.
MR. SIEBER: And the ultimate strength, as I
picture it, has tremendous uncertainty associated with it.
MS. DROUIN: That's correct.
MR. SIEBER: And that's why you don't design
bridges to the ultimate strength.
MS. DROUIN: That is accurate. Let me move on to
the next set of PRAs that came out, which are our IPEs, and
you look at the insights that were documented in NUREG-1560,
again, you still see a wide range of accident initiators are
contributing.
A thing that came out of here which we also saw in
NUREG-1150 was that your hydrogen combustion or station
blackout accident sequences was a significant contributor to
containment failure for your MARK 3's and your ice
condensers.
Those two little -- those last words got left off the slide,
but that's very important, because these refer to your MARK
3's and your ice condensers.
Some more recent research that was going on
related to the resolution of your DCH and this is a program
that was looking at your challenge to containment integrity
for just large drys and ice condenser containments for
station blackout, and the information that's coming out of
there is that hydrogen combustion can be a challenge to your
containment integrity for ice condensers during SBO.
DR. KRESS: How is that related to DCH? It's
because it's putting the hydrogen combustion pressure on top
of the DCH pressure or is it because you get additional
hydrogen out of the DCH event? I'm trying to figure out why
that particular bullet is under the DCH issue resolution.
MR. CAMP: What happened is basically this study
was done to look at DCH in ice condensers. That was the
driving purpose of the study.
When they did the study, they concluded that the
ice bed was going to be pretty effective in mitigating the
DCH part of the event.
But the calculations that they did accompanying
this with the hydrogen source terms that they got from
RELAP/SCDAP calculations and CONTAIN calculations to look at
the containment load almost always produced containment
failure from hydrogen.
DR. KRESS: So it was an ancillary result.
MR. CAMP: It was an ancillary result to the DCH
study.
MR. KING: And remember in DCH there's a bunch of
hydrogen that accumulates in the containment before the
actual DCH event and it's that preexisting hydrogen plus the
DCH --
DR. KRESS: Plus the pressurization, plus the
ignition.
MR. KING: Yes.
MS. DROUIN: And the last point that we want to
make is that as you go through and look at all these
insights that have come from WASH-1400, 1150, the IPEs,
they've all dealt with just internal events and when you
start taking the fire and seismic into control, the
accidents associated with those tend to have characteristics
very similar to station blackout.
So whereas you're getting station blackout to be a
concern from your internal, it's even more important when
you start taking into account fire and seismic.
DR. APOSTOLAKIS: Is this a good time to take a
ten-minute break?
MS. DROUIN: Sure.
DR. APOSTOLAKIS: Back at two.
[Recess.]
MR. KING: What time do you want us to finish up?
DR. APOSTOLAKIS: Well, NEI needs about half an
hour, they told me, and I'm leaving at three. So can you
finish in 15 minutes or is that too much to ask?
MS. DROUIN: Yes, we can.
MR. KING: We can. I think most of the issues
we've talked about, so the last two slides ought to go
pretty quickly. But we ought to just spend two minutes on
the last two.
DR. APOSTOLAKIS: I'm sorry. We're back in
session. Are you disagreeing with Mr. Christie's evaluation
or you are not even thinking at all in those terms?
MS. DROUIN: We're doing our own evaluation.
DR. APOSTOLAKIS: I didn't say your own. Mr.
Christie's. He presented to us his arguments why he thinks
things should go a certain way in terms of the first four
hours of the accident and after that and so on that it will
distract the operators from other important things.
So all this is in agreement with what he said or
is there a disagreement?
MS. DROUIN: I think we're in very close
agreement. What we'll do, instead of going through each of
the containment types, why don't we jump to slide 16.
DR. APOSTOLAKIS: Okay. Good. I like experienced
presenters.
MS. DROUIN: The previous slides, it just goes
into more detail, containment type, what we learned from the
various PRAs and research.
If you jump to slide 16 and you summarize what
we've learned and what conclusions did those insights lead
us to, what we're saying here is that when you look at the
results from these PRAs and from research, and you look at
that relative to combustible gases and the potential for
combustion and its challenge to containment integrity, what
we have learned from that is that a risk-informed 50.44
needs to have these kind of ingredients.
In looking at the accident types, it needs to
focus on what we would call the risk significant core melt
accidents. It shouldn't just deal with LOCAs or just the
degraded part of the accident. It should deal with the full
accident and it should focus on those that are the risk
significant ones.
DR. APOSTOLAKIS: Risk significant with respect to
public health and safety? What's risk significant for core
damage is not necessarily significant for public health.
MS. DROUIN: Public health.
DR. APOSTOLAKIS: And Mr. Christie emphasizes the
fact that we should focus on public health and safety. So
when you say risk significant, you refer to those, as well.
MS. DROUIN: I'm talking about those that can
challenge containment and that would lead to a large
release.
DR. APOSTOLAKIS: So you're in agreement.
MS. DROUIN: Yes.
DR. KRESS: Is there any concept in here of
containments leak and you put a hydrogen burn into it, that
may increase that leak? For two reasons; it may make the
hole bigger and it may increase the pressure to the driving
force.
You don't calculate a containment failure, but
there's some probability that you're increasing leak and
you've got fission products that you're blowing out at a
faster rate.
It's generally a regulatory objective to limit
that kind of release, although it's not a LERF, because it's
not the kind of large early release. It's a small early
release.
But is there any thinking in that, in
risk-informing this, that you need to deal with those kinds
of things, also?
MS. DROUIN: I wouldn't say directly, but
indirectly it gets covered. Bear with us and hopefully
we'll answer it.
The next major ingredient is what combustible
gases do you concern yourself with, and you shouldn't just
be limited to hydrogen, but also take into account your
carbon monoxide and also looking at the sources, not
limiting yourself to the fuel cladding, but also looking at
core-concrete interaction, and the source terms should be
based on realistic calculations.
When you do the realistic calculation, you may end
up at a 75 percent metal-water reaction. It might be less
than that or it might be more, but we would perform and come
up with a specified term here.
DR. KRESS: Are there any core-concrete
interaction sequences that contribute to LERF? I'll ask
Trevor, maybe, or you. I don't know. Is that a non-LERF
phenomenon?
MR. PRATT: Maybe one or two in the boilers.
DR. KRESS: One or two in the boilers.
MR. PRATT: Not in the large volume containments.
DR. KRESS: But this sub-bullet is intended to
look at it in context of LERF or just to look at it in
general?
MR. PRATT: In terms of early and late. It's a
dominant contributor to late.
DR. KRESS: So you're not limiting this
risk-informing just to early failures.
MS. DROUIN: No, and that's where we get into --
DR. KRESS: You're including late.
MR. PRATT: Yes.
MS. DROUIN: That's where we get into the next
bullet, is that in controlling the combustible gases, you
need to look at both the early phases and the late phases of
the accident.
DR. KRESS: So it's not just -- so you can't just
look at LERF.
MS. DROUIN: Correct.
DR. KRESS: Glad to hear you say that.
MS. DROUIN: Okay. If you remember, earlier, we
had said that 50.44 dealt with both what we call analytical
requirements and physical requirements. So when we look at
the analytical requirements, we are saying that the
analytical requirements, in going from what is currently in
50.44, the changes that we think ought to be done, it
should, again, account for your risk significant core melt
core melt accidents.
You need to account for your combustible gases
generations from both your fuel cladding oxidation and your
core-concrete, and specify the amount and rate of your
combustible gas generation based on realistic calculations.
So that matches up exactly to the previous slide.
These were things that were specifically called out in 50.44
and these are how we would propose the alternative for the
analytical requirements.
When we get to the physical requirements, we've
identified three alternatives. The first alternative is
taking the specific requirements from 50.44 and modifying
them. For example, eliminating the requirement for safety
grade continuous monitors, add the capability to measure
your hydrogen concentration under degraded core conditions,
such that whatever instrumentation you had there, it would
survive under high pressure, high temperature, whatever
those conditions were.
Insuring your mixed atmosphere for your risk
significant accidents, whichever they are for your
particular plant; eliminate your post-LOCA hydrogen control
system, that would be your recombiners. It would also be
your vent and purge system.
Adding a long-term hydrogen control for your risk
significant core melt accidents and ensuring your hydrogen
control for your risk significant core melt for your MARK
3's and ice condensers. These are lining up one to one to
your six physical requirements.
DR. KRESS: Let me ask you about that first
sub-bullet, eliminate the requirements for safety grade
continuous monitors. Is that based on some criteria that
says that the risk achievement worth of being safety grade
is not worth having them safety grade or is this an SSC
that's low on your priority list for some criteria?
MR. KING: It's based on the fact that these would
be used in an accident management situation and
traditionally we have not required accident management type
stuff to be the full pedigree safety grade. It will be
consistent with that approach.
DR. KRESS: Even though it might be a significant
contributor to changing the conditional containment failure
probability, you wouldn't. If it had real significance
there, you would still eliminate it.
MR. KING: See, you're not eliminating the
requirement. You're just saying it doesn't have to be
safety grade in terms of --
DR. KRESS: It doesn't have to be safety grade.
MS. DROUIN: It doesn't have to be safety grade.
MR. KING: -- all the pedigree requirements that
go with it.
MS. DROUIN: We still want you to measure, but we
aren't going to be prescriptive that the way you go about
measuring is that --
DR. KRESS: We were looking at what are the potential
requirements for things to be safety grade or not safety
grade not based on tradition, but if you had to do it again,
and the concept was, well, if it had a pretty big
contribution to RAW or Fussel-Veseley for either CDF or
LERF, then maybe it ought to be called safety grade.
But this is not the kind of criteria you used here
at all.
MR. KING: No.
MR. PRATT: I was just going to add that the
emphasis was moving away from it needed the continuous
monitoring early to an accident management strategy later.
So that gets you away from having to have the information
available for immediate responses, which we don't envisage
there would be any.
So it would be a long-term accident management.
DR. KRESS: Yes, but isn't it still needed or used
in some of the emergency response criteria? You use it
there. Wouldn't that call for sort of an early measure? I
thought it was one of the indicators that you use to decide
on emergency response measures.
MR. PRATT: In that context, it certainly may be
necessary. In the context of what we're looking at here, in
terms of hydrogen control, there's no immediate measures
that we would need, we believe, that requires this
information. That's the point.
But you certainly would probably want that
information further, but for this particular --
MR. SNODDERLY: Excuse me, Dr. Kress. This is
Mike Snodderly, Probabilistic Safety Assessment Branch. The
other thing is early I think we would be relying more on the
indicators of containment high range rad monitor and the
core exit thermocouples and then supplemented by the
hydrogen monitors as a confirmatory.
As far as the emergency planning goes, right now,
the way I see it, the way -- the biggest thing it's used for
is distinguishing between a general emergency and a site
area and is there a threat to the containment due to high
hydrogen concentration.
DR. KRESS: You could almost infer that from the
fission.
MR. SNODDERLY: Right. And I think we've
adequately addressed that, as Bob Christie pointed out, in
the ANO amendment, where we went from a -- we went to a
performance-based requirement for hydrogen monitoring.
DR. KRESS: Thank you.
MS. DROVIN: The next alternative is one where we
would eliminate all the physical requirements and replace it
with a high level type of statement to control your
combustible gases for all light water reactors for your risk
significant accidents. Under this alternative, we would
leave it to the licensee to demonstrate how they would meet
this requirement. This is much more performance-based type
of requirement.
The licensee could come in and, say the way they
meet that requirement is using the current physical things
that are there in the plant now, or they could come in and
do some type of analysis to show --
DR. KRESS: But when you looked at what they
brought to you, you would probably take these bullets up
above and say how did you deal with this, this.
MS. DROVIN: That could be one way.
DR. KRESS: It still would be the same
consideration.
MS. DROVIN: Or they could come back in and show
that they aren't challenging the containment through some
type of analysis. So, this would have a lot of flexibility
in how they would go about doing it. They could be very
prescriptive, or they could come back more in an analytical.
MR. KING: This one has an attractive advantage
for future plants. It would give them a lot more
flexibility.
MS. DROVIN: Yes.
MR. KING: So, again, it depends on how much
weight the Commission wants to put on current versus future
plants. It could drive, you know, some selection of one of
these alternative over another.
DR. KRESS: Would you put an Appendix K like thing
in there that says we want 95 percent confidence that you
don't fail the containment?
MR. KING: Well, we'd have to specify what the
performance is that we're looking for.
DR. KRESS: Yes.
MS. DROVIN: The third alternative, actually what
it is is what you see, alternative two is kind of a mixture
of alternative one and alternative three. Alternative three
is going to the strategies of the framework and
demonstrating that you're meeting those strategies so that
you would go through and demonstrate that your containment
integrity is not challenged from your combustible gases or
seeing an order of preference by limiting your radionuclide
releases or your core damage accidents or the initiating
events, or you come in and insure your emergency
preparedness.
You would go in now into your regulatory guide,
and this is where you might, for example, see numbers.
DR. APOSTOLAKIS: I was about to say that.
MS. DROVIN: Yeah.
DR. APOSTOLAKIS: But then wow, you would be risk
based.
MS. DROVIN: No, it's not in the regulation. It's
in the regulatory guide.
Then the last of this is that all of these options
may require, you know, confirming changes in other
regulations in order to get the full benefit. So, that's an
issue we would have to look at.
On that note, I'm going to get Tom wrap up.
MR. KING: Let me just take the last two minutes
and talk about slide 20, some of the potential issues we're
going to have to address in the August paper. Selected
implementation had been raised a couple of years ago when we
were talking about risk informing Part 50. I think it
really boils down to all of these things are going to be
voluntary alternatives, but does that mean you can pick,
say, 5044, for example. You can pick the current 5044, or
you take a risk informed 5044, the total package, or should
licensees be able to within the risk informed 5044 pick and
choose the pieces they like that's going to effect --
DR. KRESS: How -- what are you going to use as
guidance in deciding on this policy issue? Is this one that
you just allow the commissioners to say yes or no, or do you
have some thoughts as to why one might want to allow
selective implementation or why not? What I had in mind
there is is there some principle that if you allow selective
implementation that you can pick this one, this one, and
this one, and therefore, your risk status has changed to the
point that it's unacceptable, or your uncertainty in that is
unacceptable. Is there some thinking about what you would
use to, as a criteria, for deciding on selective
implementation or not?
MS. DROVIN: I'm giving my personal thoughts here.
I think that if you allow selective implementation within a
regulation, you're not risk informed because the risk inform
is supposed to focus in on the risk significant. In some
cases, there may be cases where to be risk informed, it's
just reducing things. There may be cases, as you see in
5044, to be risk informed, you're going to take some things
away, but you're going to have to add some things. There
were things missing.
DR. KRESS: So, you're thinking it's either a
whole package or not at all?
MS. DROVIN: And I think that if you allow
selective implementation, then you would just go after those
things that are going to reduce, but the things that were
safety significant --
MR. SIEBER: Compensatory.
MS. DROVIN: -- may not be selected. I don't
think that's a risk informed regulation.
MR. KING: We have already said risk informed is a
two-edged sword. When you go in and, well, the risk
information can lead you to --
DR. KRESS: I was assuming both edges of the sword
would show up in each individual regulation, and I may be
wrong there, so that I could choose this regulation, but I
have to choose all of that particular regulation. I get
both ends of the sword there.
MR. KING: Yeah, yeah.
DR. KRESS: And then I would allow selective
implementation because --
MR. KING: On a regulation by regulation basis.
DR. KRESS: Right, regulation by regulation basis.
MR. KING: Yeah, I think that's Mary's personal
opinion is what she likes, and I think we're going to have
to go to the Commission with a recommendation and talk about
the criteria to why we picked that one, whatever it ends up
being.
MR. SNODDERLY: Sorry, Tom. I think, Dr. Kress, a
concrete example of that would be the Mark 3 containments.
So, right now, we had igniters for Mark 3 containments, but
from a risk study, we knew that 96 percent of the risk is
from station black-out sequences. So, the igniters aren't
available during -- they're not there. So, it doesn't make
sense to say okay, we're going to risk inform this
regulation, and the Mark 3 owners are going to say hey, you
know what? I like that I don't need recombiners, and that
makes sense, but does it also make sense, as you've gone
through this process to say, shall we continue to allow this
anomaly to exist?
Now, there's a lot of other things to consider,
but I think like that's a hard example of what, you know,
that we -- one example.
MR. KING: Okay, and it's related to the backfit
question. If you're going to do a backfit analysis, are you
doing it piece by piece, or are you doing -- taking the
whole rule as a package and doing the backfit and looking at
the aggregate of how things come out. Also, the backfit,
one of the stakeholders raised the question of the reverse
backfit test. If we are, you know, ending up net burden
reduction, should there be some, you know, tangible benefit
in doing that? Should there be some criteria for which to
do that? So, that's part of the issue when we talk about
backfit.
The risk informed guidelines we talked about,
that's the issue of using the safety goals and the
subsidiary objectives as the guidelines for making the
changes. I mean, that has to be a Commission decision
versus future plants, how much weight do you give from one
to the other. Technical issues, long-term containment
performance -- one of the NEI comments was they didn't think
that ought to be a consideration. We're going to talk to
them about that tomorrow.
Defense in depth, it's the issue, George, you
talked about, rolling those considerations up as something
the Commission can deal with is an issue. Safety margins is
the same thing, and treatment of uncertainties is tied in
with that. So, a number of things that we're going to have
to lay in front of the Commission that aren't just unique to
5044. I mean, these things are generic to this whole risk
informed process.
With that, I think we've talked about the schedule
already, so that's it.
DR. APOSTOLAKIS: Any questions? Any comments
from the members?
DR. KRESS: Well, I'd like to offer my
encouragement to this framework. I think they're going in
the right direction. You know, I may argue with some of the
details right now, but yeah, I think it shows some good
thinking and some good progress. I like the approach, at
least.
DR. APOSTOLAKIS: Speaking of the approach, the
three alternatives that you put up there, you will evaluate
those in some way at some point, or are there preliminary
alternatives? Is that the idea?
MR. KING: Right now they're preliminary
alternatives. I think there's an open question. We go to
the Commission in August. Do we recommend one of those, or
do we recommend to the Commission that each of these has
some merit, and maybe the next step ought to be an advance
notice of proposed rulemaking to get feedback on those three
alternatives.
DR. APOSTOLAKIS: Once you do any sort of analysis
to --
MR. KING: Enough analysis to say that they're
feasible. We don't want to give the Commission unfeasible
alternatives.
DR. APOSTOLAKIS: No, they are feasible, but I
mean, if I go with alternative two versus alternative three,
what am I doing to the condition containment failure
probability, for example?
MR. KING: Pros and cons kinds of things, yeah.
DR. APOSTOLAKIS: You will do that kind of thing?
MR. KING: Yeah.
DR. APOSTOLAKIS: Quantitatively.
MR. KING: As best we can.
DR. APOSTOLAKIS: As best as possible. I knew
that was coming. Okay, thank you very much. Any other
comments? No?
DR. KRESS: I also wanted to mention, I would hope
at some point along the line that uncertainties get more
explicitly built into the criteria.
DR. APOSTOLAKIS: I think in the July subcommittee
meeting, we'll probably have a lot to say about that.
DR. KRESS: Yeah.
MS. DROVIN: We skipped over that slide.
DR. KRESS: Yeah, okay. Maybe so. I'll look
through your slides.
DR. APOSTOLAKIS: Well, I don't know whether we
want to ask how this is affecting the rulemaking, but Mr.
Christie requested.
DR. KRESS: Well, that wouldn't hurt to ask.
DR. APOSTOLAKIS: Whom do we ask? Do we ask you
or the NRR?
DR. KRESS: I think ask these people over here.
MS. DROVIN: Ask Cindi.
MS. CARPENTER: This is Cindi Carpenter from NRR.
Basically, we have the petition for rulemaking. It was
noticed, and we're waiting -- it basically is being
incorporated into what they're doing in Option 3. Option 3
in 5044 is going to provide the technical basis for how we
resolve that petition for rulemaking, so they're very well
aware of what Mr. Christie has proposed, and we're waiting
on the outcome of that right now.
DR. APOSTOLAKIS: So, the technical basis you are
referring to is the August document?
MS. CARPENTER: The August and probably the
December document also, I'm thinking.
MR. KING: The August document --
MS. CARPENTER: The August, okay.
MR. KING: -- would be the one that deals with
this issue.
DR. APOSTOLAKIS: Okay, thank you.
DR. KRESS: I'm glad to see the National
Laboratories so well represented.
DR. APOSTOLAKIS: So, the next presentation is
from NEI, and it's on a different subject, 10 C.F.R. 50.69
and Appendix T.
DR. SHACK: Option 2, Option 3, we cover
everything.
DR. APOSTOLAKIS: Boy, this is a dynamite
subcommittee meeting. Mr. Floyd, would you introduce your
colleagues, because we have not seen them before.
MR. FLOYD: Yeah, right. To my left is Adrian
Haymer, and to my right is Biff Bradley, all from NEI.
DR. APOSTOLAKIS: Wonderful.
MR. FLOYD: We're actually going to talk about two
topics today. We have some brief comments on Option 2, and
we also have some brief comments on Option 3 to cover.
DR. APOSTOLAKIS: Very good.
MR. FLOYD: Okay, with respect to Option 2, just
wanted to advise the committee here that we have submitted
the PRA certification industry peer certification process to
the Commission formally for review. It's in a document
called NEI-00-02. All plants will be peer reviewed by the
end of 2001. Our status right now is that all the boiling
water reactors have completed the peer certification
process, and I don't know, maybe perhaps as many as 25
percent of the PWR's at this stage, but they all are
scheduled to be completed with their review by the end of
2001.
DR. KRESS: Is your intention to say that peer
review would correspond to Category 2 or 3 in the ASME
guide? Say that you would like to say go through this peer
review. Then we correspond to Category 2 or 3, or are those
completely separate?
MR. FLOYD: They're somewhat separate because we
don't know what the final form of the ASME standard will be.
What we're saying and what we suggested in our letter is
that the peer certification process is adequate and
appropriate for Option 2 of risk informing Part 50.
DR. KRESS: Okay.
MR. FLOYD: It may comport with what the final
ASME standard comes out with in one of the categories, but
we don't know that at this point.
MR. BRADLEY: It's an application specific review.
MR. FLOYD: Yeah, and we're saying that only for
this Option 2 application.
DR. KRESS: Okay.
DR. SHACK: Just, I got confused about this this
morning. Since you're not grading the whole PRA, you're
doing it element by element, do I then get a list of
elements that have to be grade three or above to support
Option 2, or do I get an overall road map that really tells
me now?
MR. BRADLEY: I think those are issues that we're
going to get into when we get into the review process with
NRC. I think our initial thinking is, you know, there is no
overall grade. There's a grade on each sub-element, and
generally speaking, I think we're talking about something,
you know, for most of the sub-elements, a grade level three
in the certification process to support Option 2.
One of the things we've got to do is coordinate or
correlate our Part 50 guideline document in that whole
process with the certification process so that as we do
that, it will become more clear which elements are most
important. I think the general thinking of what I saw from
NRC, and probably we don't disagree, is that we're looking
at a level three for most, if not all, of the sub-elements
to support that.
DR. KRESS: My first thought, Bill, is I was going
to find out, look and see how much -- which elements are
more important, put a weighting factor on and take the
grades and get an overall grade. Anyway, they're probably
doing something like that but not putting numbers on it.
MR. FLOYD: And I think the third bullet really
goes to what we've been talking about, is at the meeting
that we had this week, the NRC did lay out at least the
outline of what the review process will be for the peer
certification process.
The other item we had down here, as you know, the
South Texas nuclear project has an exemption request in, and
of course, one of the concerns the staff has is how does
that relate to the overall Option 2 generic rulemaking
issue. South Texas has prepared a matrix comparing their
risk categorization and treatment process to the NEI
guideline process approach. We haven't had a chance to
fully review that, but in general, it looks to be -- looks
like they captured the essence of it.
The conclusion we think we would agree with is
that, although when you get down at the level of detail,
their approach is a little bit different. When you get at
the how-to level, the concepts and the philosophy that are
embedded in the guideline document are consistent with the
approach that they had. That wasn't by happenstance. Of
course, we were cognizant of what their approach was when we
were developing the guideline document, as well as being
cognizant of the ANPR and the SECY papers. Our guideline
document has been evolutionary to accommodate those changes
as they've gone along.
The other thing I wanted to say in general about
Option 2 here is that, just give you an update on the pilot
status. NEI has been coordinating with the owners' groups a
pilot project effort to test out a number of systems at lead
plants in each of the owners' groups. So far, the
Westinghouse, BWR owners' group and CE owners' group have
all now voted to fund a project.
The scope of the projects are very similar in
scope and schedule. They will be starting roughly in the
September time frame, late August, early September time
frame, and having the preliminary bulk of the work done by
around the end of the year and then writing up an evaluation
report.
All three owners' groups will be using the NEI
guideline as their template for conducting their review to
see what enhancements and revisions need to be made to the
guideline document as we move forward.
Some other Option 2 issues, we've identified a
couple of issues, I think, the we would like to get an early
read from a legal perspective. The first one is the
differentiation of design basis from special treatment. Let
me see if I can explain what we mean by that. Take, for
example, the environmental qualification rule. We view that
as a special treatment requirement. We hear some in the
staff say that no, part of the design basis is the specific
special treatment requirements that are embedded in the 5049
regulation. That makes a big difference on how we write our
guideline and what special treatment provisions you put in
place, and also it makes a big difference as to what the
bottom line benefit of Option 2 is, depending upon the
resolution of that issue.
So, we'd like to get a fairly timely read from the
agency on what is their position with respect to the
relationship between special treatment requirements and the
design basis requirements. Are they one and the same, or
are your design basis requirements -- I mean, our view is
that, for example, in the EQ area, if you have a pump that
has to deliver 100 gallons per minute to each steam
generator under a harsh environment, that's the design basis
functional requirement.
The special treatment regulation is the how do I
provide that assurance that it can do that. There may be
other ways of providing them, and we're really talking about
the RISC-3 category here, by and large, which is the low
safety significant but safety related category. Do you need
that same degree of pedigree that's embodied in 5049 to
provide a reasonable assurance that that design basis
function is agreeing under those high energy line break
conditions can be met.
DR. KRESS: It seems like if you're going to be
risk informed, that that's the appropriate way to view it.
MR. FLOYD: Well, that's our view. In fact, it's
almost an oxymoron to say that if the intent of the Option 2
approach is to grade the pedigree of treatment, but you
can't do that because the pedigree of treatment is indeed
part of the design basis, and you can't change the design
basis, you, in essence, don't have an Option 2. We just
want to get it nailed down and get agreement on that. We've
heard conflicting opinions on that.
The second issue is related to Part 21, and its
applicability to really RISC-2 and RISC-3 boxes. The
position that we've taken in the guideline is that Part 21
is certainly applicable to the RISC-1 box. It's not
applicable to the RISC-2 box because the RISC-2 box doesn't
contain components that pass the definition of what is a
basic component. Our position in the RISC-3 box is that
Part 21 also would not apply because the test in Part 21 is
you have to have a substantial safety hazard as a result of
the deficiency. We're talking about items that if we
have agreement on the risk categorization process, we've
defined that if they were to have a problem, they don't
create a substantial safety hazard. So, that's our
position, and we, again, would like to have an early-on
legal read of that from the agency, again, because it has
great bearing on how we develop our guideline document and
the overall benefits of Option 2.
Next issue we have is commercial treatment for the
RISC-3 category. This is where, obviously, all of the
discussion or the bulk of the discussion has gone on to
date. We have provided in our early draft of our guideline
to the staff what is known as an Appendix A, which they
characterized earlier this week as a good outline of the key
elements that should be in a commercial program. The
feedback we got was that they would like to see some
additional detail in the document, not so much on the how to
you provide, the assurance that the design basis function
will be maintained, but what are the desired results and
outcomes that you'd like to see from that.
So, we're looking now to go back and see if we can
add some more detail to the Appendix A that focuses on
desired results outcomes, without getting into the how to.
This is the difficult road to walk down because we could
very easily wind up replacing 18-point criteria in Appendix
B with a very detailed and prescriptive commercial program
if we go too far in one direction. Then you've eliminated,
again, the benefit of trying to reduce emphasis on low
safety significant SSC's.
DR. KRESS: The parts that you are going to -- the
components that you're going to get from the commercial
program, it seems to me like there ought to be some thinking
about what is the actual reliability. There ought to be
enough data out there to say that in general, the
reliability of commercial parts for this particular pump or
whatever it is has this mean and this variance, and
therefore, it very well meets the requirements I have on my
PRA that shows this is not a safety significant thing.
You wouldn't have to go into the -- you know, it's
sort of a Bayesian approach. You wouldn't have to go into
the commercial process and what they do and what their
quality controls are. You just use the database. Is there
any thinking along that line?
MR. FLOYD: Yeah, there is. We actually see two
elements in it. That is certainly one element, and we think
that's appropriate for those design basis functions which
can be routinely monitored through normal plan operation.
That's an appropriate way to treat those. We acknowledge
that there are other certain design basis functional
requirements in harsh environments, for example, or seismic
conditions that you're not going to be able to do that
monitoring for. So, then you need to have some design
control and procurement control aspects put in place to
assure that the equipment is being ordered with those
considerations in mind.
MR. BRADLEY: There may be uses in other
industrial applications where the equipment, it spurns
routinely to a harsher environment, and you might be able to
get some benefit out of that.
DR. KRESS: Yeah, that's what I had in mind, other
industrial applications.
MR. BRADLEY: Right. We will be looking at that.
MR. FLOYD: Right, looking at those.
DR. APOSTOLAKIS: You mentioned the benefits. Do
you have any idea what -- I mean, if the industry implements
this, what the benefits will be to them in terms of dollars?
MR. FLOYD: The only plant that's really looked at
in much detail is south Texas, and they're telling us that
this could have benefits of, you know, in the $2 million, $3
million per year potential in terms of, largely in the
procurement related area, procurement and inventory control.
DR. APOSTOLAKIS: So you think that will be more
or less the ball park?
MR. FLOYD: It's hard to say. That's really what
the -- because they're a little bit unique because of their
late vintage of their licensing basis for their plant. They
have a lot more safety related SSC's identified in their
licensing basis than a typical plant has. That's really
what the pilots, I think, are going to tell us, which is why
the owners' groups are very interested in having a scoped
pilot effort that will give them some of those answers.
DR. APOSTOLAKIS: It might be less for others?
MR. FLOYD: It could be less for others, and it
may turn out that that is representative. We just don't
know yet.
DR. APOSTOLAKIS: And after these savings are
realized, then people will spend a billion dollars to have a
good level three PRA perhaps?
MR. FLOYD: Well, you know, we are going to talk
about that a little bit in just a few more minutes, but no,
I think --
DR. APOSTOLAKIS: Category three.
MR. FLOYD: This is a market-drive, I think,
application in general, and I think if people start seeing
the benefits of applying risk technology, and the benefits
are real intangible, you're going to see people embrace them
more strongly and be willing to make a greater investment in
it.
DR. APOSTOLAKIS: And after they do that, we'll
need a new ASME standard because everyone will be category
three.
DR. KRESS: We'll have to have a category four?
MR. BRADLEY: Don't get too far down the road.
We've got to make the baby steps first here.
MR. FLOYD: The other issue we have on Option 2 is
treatment of prior commitments. As we know, and I think as
we talked before at this committee, a typical plant has
somewhere around eight to 10,000 commitments. These are
things that are beyond strict regulatory requirements. Many
of them are the way the licensee has chosen to meet a
specific regulatory requirement, but nonetheless, that's
about a ball park number in the order of eight to 10,000 per
plant.
What we would hope could happen under this Option
2 approach would be a replacement, a blanket replacement, of
those current commitments, which by and large, went to
special treatment considerations and, you know, pedigree of
equipment, with an acknowledgement that the new risk
categorization process and the new defined treatment process
for the various boxes is indeed a replacement for the
previous commitments, without making a licensee go through
the commitment management guideline, which has been endorsed
by the agency, and write up a piece of paper for each of
those 8,000 commitments to disposition it. We'd like to see
a blanket replacement. Otherwise, it is a fairly extensive
bureaucratic process to go through to officially eliminate
those commitments from the docket.
DR. BONACA: Just before you leave this overhead,
I would like to ask you about Part 21. The benefit there is
that probably in the procurement components which are not
subjected to the requirement.
MR. BRADLEY: Yes.
MR. FLOYD: Yes.
MR. BRADLEY: Well, Part 21, it's imposing a
significant liability on the vendor or the dedicator, so
even if we can have -- let's say relaxation of other
requirements, if Part 21 is still there, much of the benefit
is not going to be gained.
DR. BONACA: Certainly, however, there is still a
benefit to the industry of communicating problems of the
components, and maybe they could be communicated in other
vehicles than Part 21.
MR. BRADLEY: Yes, we've thought about that as
well, that maybe, you know, there's ways to meet the intent
without imposing a type of liability that drives the parts
prices up.
DR. BONACA: Or eliminate suppliers, actually,
because I mean, some of them don't want to supply any more.
MR. BRADLEY: Right, and this is an issue. On
RISC-2 where you may say, you know, in a BWR, for instance,
at the condensate system or feedwater system is risk
significant, you know, trying to impose Part 21 on those
types of vendors would probably be very problematic for the
industry.
MR. FLOYD: As a close-out for Option 2, I think
I'd be remiss if I didn't say that I think we've been having
some very good meetings with the staff on Option 2.
Obviously, the industry has some more gelling to do. The
staff has some more gelling to do with respect to positions,
but philosophically, I don't think we heard anything in our
last meeting this past week that is greatly out of sync with
what the industry thinks is the necessary things to do with
respect to treatment for the SSC's under Option 2. So, I
think we're on the right pathway.
I'd like to switch now to Option 3. We do think
that there has been a tremendous amount of thought and
effort put in by the NRC staff in establishing the Option 3
framework. Some of the comments specifically that we have,
and we provided these in our public comments, we tend to see
that -- we think this is leaning a little bit more towards
risk base than risk informed. At least our impression. It
may be a wrong impression, but there seems to be more
emphasis on the bottom line number results and less on the
integration of the thought process that's embodied in Option
2 approach with the integrated decision making process.
DR. APOSTOLAKIS: I didn't get that impression
from the representation.
MR. FLOYD: Okay.
DR. APOSTOLAKIS: But again, risk based is
something that should be avoided at all costs, right?
MR. FLOYD: It comes across more in looking at the
framework than I think it does on the individual rulemaking
efforts, you know. This is more a comment on the framework
document, I think, than --
DR. APOSTOLAKIS: Well, they go out of their way,
as I pointed out, than earlier, to state in several places
that risk numbers will not appear in the regulations. I
thought that was excessive. So, I guess it's in the eye of
the beholder. An excessive number of times. I mean, they
can say it once. Not that they went too far, although that
might be the case, too. I don't know. We're going to have
a subcommittee meeting July 11 at 1:00 to discuss the
framework here, Option 3. It was decided today.
MR. BRADLEY: That's one none of us can support.
We have a --
MR. FLOYD: Right, we have a risk informed
regulation working group meeting on the 11th.
MR. HEYMER: And a date with senior management.
MR. FLOYD: And senior management, PRA steering
committee meeting with the staff on Monday morning.
MR. BRADLEY: One thing, since you mentioned this,
it might be helpful is we could -- there's so much going on
in risk informed right now. One of the reasons we couldn't
be here all day today is we have many meetings going on
within the industry. If possible, if we could coordinate
our schedules in advance, we might be able to support these
meetings.
DR. APOSTOLAKIS: I believe that is an excellent
suggestion. Let me tell you about today's meeting. I mean,
it was scheduled, really, this afternoon when we realized
that the emphasis on the staff's presentation today was on
5044. You know, the committee really has not been given the
opportunity to discuss the details. So, it was something
that it was decided at the last moment, but I think this is
a great idea because, you know, I at least learned a lot by
hearing different viewpoints.
MR. FLOYD: Right.
DR. APOSTOLAKIS: It's unfortunate. Maybe you can
go back and look at your commitment and maybe one of you can
show up for awhile.
DR. KRESS: But that seemed to be about the only
date we could come up with.
DR. APOSTOLAKIS: Yeah, this is the only day, you
see, because it's just before the full committee meeting.
MR. BRADLEY: Well maybe just make an effort to
share our schedules and try to do that.
DR. APOSTOLAKIS: No, we will. Are you in town
that week?
MR. BRADLEY: They are in town that week. I'm on
vacation.
MR. FLOYD: We're partly in town that week.
DR. APOSTOLAKIS: I mean, if you can show up
around 4:00. Do your meetings go late?
MR. FLOYD: They go -- this one is from one to
5:00 in the afternoon, since we're meeting with the PRA
steering committee in the morning from nine to 11:00.
DR. APOSTOLAKIS: Anyway, that's --
MR. BRADLEY: Your full committee meeting is the
12th?
DR. APOSTOLAKIS: Yes. You plan to be there?
MR. BRADLEY: Yeah, that's probably a date we can
-- I can't speak for you guys.
MR. FLOYD: You might have to cover it, Adrian.
DR. APOSTOLAKIS: Okay, so maybe then we can give
you some time.
DR. KRESS: That would be helpful. That would be
in time before we wrote our letter.
DR. APOSTOLAKIS: Yeah.
MR. FLOYD: As you know, it's hard to schedule all
of these meetings that are going on and all the parties that
are interested in what's going on in risk informed
regulation. That is a challenge to get the schedules to
match.
DR. APOSTOLAKIS: That's right, but especially for
issues like Option 3 -- I mean, on Option 2. It seems to me
we really have to go through and scrutiny every detail
because these are major pieces of regulation.
MR. FLOYD: Right, significant changes.
DR. APOSTOLAKIS: Now, the second bullet --
MR. FLOYD: Yeah, let's get to that one.
DR. APOSTOLAKIS: What is it that bothers you
there, the fact that they are using the safety goal numbers
--
MR. FLOYD: What's bothering us --
DR. APOSTOLAKIS: -- as given by the Commission,
or the idea of using safety goals?
MR. FLOYD: No, no, not the idea of using safety
goals. It's the way in which the safety goal is being
applied. Our understanding is that the current policy
statement is that safety goals are to be applied on the
general fleet of plans and are not to be used on an
individual plant basis. Our read of the framework document
seems to be driving it more towards the intent to use it on
an individual plant basis, and that hasn't been a policy
decision that has been made yet.
DR. APOSTOLAKIS: If you use 1174, you're using it
on an individual plant basis.
DR. KRESS: That's much more so there than you are
in this.
DR. APOSTOLAKIS: But those numbers there come
from the QHO.
MR. FLOYD: Well, 1.174 is really for evaluating
individual changes that you're making --
DR. APOSTOLAKIS: But individual plants --
MR. FLOYD: -- but it doesn't specifically say
anywhere in Reg Guide 1.174 that you cannot exceed either
the minus four or ten to the minus four core damage
frequency.
DR. KRESS: My reading of the framework document
would say that they're using these safety goals just like
they were intended, and that is to gauge how well they're
writing the regulations to get the fleet of plants on an
average down there. They won't say each individual plant,
you have to meet this safety goal. They're going to say
we're going to write the regulations so that on the average,
there is a tendency to, if they follow these regulations,
there is a tendency that they might meet the goals, but not
each individual plant. That was my reading --
DR. APOSTOLAKIS: Yeah.
DR. KRESS: -- that they were just using them just
like they were intended to be.
DR. APOSTOLAKIS: I had a different reading. I
thought that before you know it, if you use them like that,
they will become measures of adequate protection, and that
ws not the original intent.
MR. FLOYD: No, it was not the original intent.
MR. BRADLEY: Well, I guess the fact that we have
different readings says something, that maybe --
DR. APOSTOLAKIS: That we should have a
subcommittee meeting.
DR. KRESS: To clarify this.
MR. FLOYD: It's an issue that needs to be in
here.
DR. APOSTOLAKIS: No, this is an important issue
in my view.
MR. FLOYD: Right.
DR. APOSTOLAKIS: This is one of the most
important issues --
MR. FLOYD: Right.
DR. APOSTOLAKIS: -- because just because the
numbers are there and you don't have any other numbers, it
doesn't mean you have to start using them to do certain
things for which they were not intended.
I thought the issue of the applicability of the
goals in the individual plants had been settled. We were
discussing this.
MR. KING: It was settled in 1174. It was raised
as a policy issue, and the Commission said yes. They said
yes in the context of 1174. They haven't said yes in the
context of revising the regulations.
DR. APOSTOLAKIS: So the Commission is allowed to
have selective implementation.
MR. KING: But you're only going to raise this as
a policy issue. I mean, I think clearly, this is something
the Commission needs to weigh in on.
MR. FLOYD: Especially if you're going to be risk
informed and you realize that not every plant needs a ten to
the minus fourth core damage frequency to meet the
quantitative health objectives and the safety goal.
DR. APOSTOLAKIS: That's my concern, too.
MR. KING: That's our concern.
DR. APOSTOLAKIS: It may turn out to be a measure
of inadequate protection, not adequate. That's not the
original intent. See, if it's adequate protection, it's
risk based. If it's a measure of inadequate, then it's
still risk informed.
MR. BRADLEY: And 1.174 was written to go beyond
adequate protection.
DR. APOSTOLAKIS: I can play the word game as well
as you can. I'm sorry, Biff.
MR. BRADLEY: 1.174 Contains a discussion of the
fact that it was intended to establish measures beyond
adequate protection. It's not intended to define what is
adequate protection.
DR. APOSTOLAKIS: That's true.
MR. BRADLEY: Yeah.
MR. FLOYD: Our third bullet really goes -- is a
corollary to the second bullet, and it's the policy issue.
We think that is a departure to apply again the subsidiary
objectives of the safety goal on an individual plant basis,
and that was our read as to what it looked like it was going
towards.
The last bullet, I think, is perhaps one that's a
little bit interesting, and it goes to what Tom was talking
about in his presentation about the application of the
backfit rule. I don't think anybody in the industry
disagrees that if there is an outstanding issue out there
that does show a cost benefit for being a provision in one
of the Option 3 risk informed changes that it's appropriate
to put it in, that's fine. We don't see any clear guidance
yet in the framework document, which would suggest that
additions that want to be made to requirements that aren't
included today would, indeed, have to pass some sort of
threshold criteria, and what is that criteria before they
would be imposed under the Option 3 framework.
I mean, our understanding is that under the Option
3 framework, we are looking for, you know, improvements in
the effectiveness and the efficiency of the regulation by
removing unnecessary burden and by focusing the regulation
on that which is important. While our understanding is that
with this double edged sword, we're only going to be allowed
to make minor changes, we think if there are significant
additions to the requirements, they ought to have a criteria
of what level of significance do they have to add value for.
Otherwise, they just become potentially another candidate
for a reduction at a later date because they're not
effective, and we don't know what that criteria is at this
point.
Overall, and these words probably more come from
our working group than anybody else. What we're really
looking for in Option 3 is a pragmatic versus a more
theoretical approach. We really think that the best
approach in Option 3 is to use generic risk insights. In
fact, when we think about what the role of the regulations
is to be applicable to a fleet of plants, we're not sure
that you need a great deal of plant specific detailed PRA
information to adopt Option 3. What you ought to be
looking at are broad, generic insights from PRA results
across a fleet or a subset of the fleet of plants rather
than being too focused on the actual plant specific PRA
results. Now, there may be certain cases where that's
appropriate, depending on how the regulation is written, but
in general, we think it ought to be a generic application
for a generic rulemaking.
As we've said, we want to make sure that we do
preserve the risk informed philosophy and make sure we don't
get too risk based in this by focusing too much again on
numbers and plant specific PRA results.
DR. SHACK: Would that mean, for example, that you
don't particular like the alternative two approach to 5044,
where it would be very plant specific?
MR. FLOYD: Yes. We think it would be better to
have a generic rulemaking which stands back and looks in the
big picture, what are the important things for -- maybe it
doesn't apply to all the fleet of plants, but maybe you have
to break it up into subsections of a fleet of plants, that
these are the items that our insides tell us are important
to pay attention to from a public health and safety
perspective, and then write a generic rulemaking around that
framework.
DR. SHACK: Just coming back to your bullet in the
previous page where you've objected to the quantitative
basis. Now, is that the particular number or just the
notion of a quantitative basis?
MR. FLOYD: No, I think it's the particular number
focused on a plant specific result as opposed to -- yeah,
certainly we think it may not be inappropriate to have a
quantitative basis for it. That's applied generically based
upon insights from a population of plants. Biff and Adrian,
jump in here is you have any problems with that. No, okay.
Our recommendations under Option 3, as we had in
our letter, were to complete the ongoing efforts that are
going on in hydrogen control and the fire protection, 50.48
Appendix R effort. The greatest -- we did a survey of the
industry last fall, and all our indications are is that the
results of that survey are not any different today. The
feedback we're getting is that people think the areas that
are most right for improvement are codes and standards under
50.55(a) and the large break loca analysis, 50.46.
DR. KRESS: Can I ask you a question about that?
Let's take the large break loca. We've got the 50.46 rule
and Appendix K, which imposes certain requirements on the
plants. Now, if they're going to risk inform that, then
there will be another kind of rule with different
requirements imposed. In order to get a benefit estimate,
you must have had some sort of notion of what this new rule
is going to look like in order to determine what you're
going to be allowed to change and do. I'm not sure, without
your having the actual new risk informed rule, I'm not sure
what assumption was made in, say, the NEI letter where these
showed up. How were these cost estimates arrived at?
That's my question.
MR. HEYMER: On the 50.46, most of the responses
were from -- not all the responses, but most were from the
Westinghouse plants, who used the data that they developed
under the owners group approach to define what the benefit
might be from the Westinghouse owners group activity
associated with the large break loca. In that, they'd made
some preliminary assumptions and from their preliminary
work, they thought that they could get down to a specific
break size in redefining the large break, and based on that.
DR. KRESS: They made some assumptions.
MR. HEYMER: Yes, they made some assumptions.
Now, obviously, the larger the break size, perhaps the lower
the benefit, but I mean, that's what they based it on, and
some of the other owners groups who provided information to
us said they didn't think they could go that way, but they
felt there may be some benefit if they applied the follow-on
activities from a large break. Whether or not they came
down to the same size at the Westinghouse owners group was a
matter of debate. So, there was some provisional -- it was
preliminary. We acknowledge that, but at least it gave us
some indication of where we might go.
DR. KRESS: It gave you an indication.
MR. HEYMER: Yes.
DR. KRESS: Probably good enough numbers for doing
prioritization, anyway.
MR. HEYMER: Yeah, and then once you get into it,
you know, you re-assess that as you go along.
DR. KRESS: As I said, after the rule just some
conformity.
MR. HEYMER: And obviously before the executives
say move on. They want some harder numbers still.
DR. KRESS: Thank you.
MR. FLOYD: Some of the non-Westinghouse plants
also were looking at elimination of the requirement to
consider a loss of off site power coincident with the double
ended guillotine break as one approach, as well as removing
some of the conservatisms, the known conservatisms in the
Appendix K analysis.
DR. KRESS: Eliminating the loss of off site
power. Is that because you've got it down to such a low
probability that it's not --
MR. FLOYD: Yes. If you look at the probability
of the large break size coincident with the loop, you're
pretty far down.
DR. KRESS: Pretty far down. Okay, thank you.
MR. HEYMER: Just a quick point on the codes and
standards. It wasn't really clear from the survey when we
went back to people and asked questions whether the benefits
that they were quoting were really just from what they might
achieve under Option 3 or what they might achieve through
Option 2 as well. Some people who put numbers in there
hadn't implemented ISI or IST-type of activities.
MR. FLOYD: And then obviously, the desired
approach that the industry really has is they think if we
could focus on the codes and standards and large break rule,
that that will probably flush out the preponderance of the
policy issues and the degree of rigor that will have to be
demonstrated to make these changes, and then they will be in
a better position at that point to look at prioritization
for remaining regulations.
We actually think while that sounds like that's a
slowing down of the effort, we really think that would
actually result in a speed-up of the overall effort because
we'll either know the benefit is there and as the desire to
move forward or not. When we get the results from these
first two efforts, then we'll know the magnitude of the
policy issues that will have to be likely dealt with.
This next one, again, this is just a perception.
Perhaps it's because we've had a lot more dialogue with the
staff on Option 2 than Option 3. The timing is a little bit
different on the two efforts, at least with respect to our
involvement and interactions. We do see, at the front end,
maybe a little bit different and fundamental approach.
We see the research effort perhaps, again our view
being a little bit more focused on the plant specific PRA
results and the importance of the number. That's an
impression that we have, and we see the NRR side. While
that's certainly an element, we see them very much more
concerned, perhaps, about some of the other elements that
are not covered by the PRA being brought in.
Perhaps, as I said, it's a function of the level
of dialogue that we've had to date on Option 2 versus Option
3 that's driving that, but that's an early perception that
we have. If that fundamental difference does indeed exist,
then we think it would be of great benefit to sort that out
and make sure that we have a consistent approach from both
offices in the agency.
I will comment, and I think this is just the
nature of the beast that we're dealing with on the second
bullet, that most of the meetings we've had to date on
Option 2 really wind up focusing on what do you do with the
stuff that your risk categorization process tells you is not
very important, and sometime I know we're going to have to
get over that, but at some point in time, we really need to
start paying attention to what's the stuff that we all think
is important and making sure that we're dealing with that
correctly and figure out how to not spend so much time
worrying about the unimportant or less important stuff.
DR. SHACK: How comfortable are you with you
agreement over what it's going to take to decide what's
important and what's not important?
MR. FLOYD: Do you want to address that, Biff?
MR. BRADLEY: How comfortable we are with the
agreement?
DR. SHACK: The categorization.
MR. BRADLEY: Well, I think really that's the
driver of this issue. To some degree it's a degree of
confidence in the categorization process.
DR. SHACK: Oh, well I thought the argument was on
the actual treatment that you would give to the low risk
significant.
MR. BRADLEY: Right.
DR. SHACK: But not whether on what you decide.
MR. BRADLEY: We're more comfortable with the
categorization element than we are with the treatment
element. It seems that -- I think, you know, we've done
categorizations of more of a limited scope thing, a
maintenance rule, ISI, IST. Those are, you know,
categorization, graded QA. There's some sense of you can do
that and success.
There seems to be more controversy and more
difficulty trying to decide what do you do with it once
you've binned it, you know, and there's not a -- you know,
you can always be really conservative in the categorization
process to take care of any disagreement, but then once
you've done that, you know, that in itself doesn't give you
anything. You've got to do something with the two bins, and
that's where the difficulty is, more controversy.
So, it's also where the whole benefit would
evolve. So, just having an agreement and a mutual
understanding on how to categorize doesn't tell us
everything we need to know to have success, you know, and
widespread buy-in into these efforts.
I think we'll get there. It's always difficult,
and there's a long history to some of these things, and
change is difficult, but you know, I believe we can get
there. Steve's right, you know. There seems to be an
inordinate focus on things that everyone seems to agree on
low safety, you know, significant in the categorization
process.
MR. HEYMER: When the NRC staff are planning some
visits to plants to look at some of the programs that will
be applicable to the low safety significance, and I think
once they've seen those, I think it will ease the path of
resolution. There will be a better understanding from the
NRC side of what we really mean by commercial or commercial
nuclear practices. I think one we've got through that
phase, there will be a much better understanding, and we'll
have a better idea of where we're going and how far we can
go.
MR. FLOYD: And just a final observation, and it
really goes to what Dr. Apostolakis referred to just a
little bit ago, and that is there is, we think, a limited
window of opportunity for getting general support within the
industry for these initiatives. It's expensive to be a
pilot plant. It's expensive to kind of go out on your own,
as South Texas has. The longer that review takes, the more
resources that are applied to it.
If we could show some timely resolution on 5044
and action on the South Texas exemption request, I think
that will spur the rest of the industry on to be much more
interested and engaged in applying risk technology, and will
probably promote better PRA models and a desire to upgrade
PRA models and get better information, which personally, we
think, is to the benefit of the overall industry and public
health and safety. We think there's just so much
information that's available from the insights that you get
from risk analysis, that we'd like to see a strengthening of
those abilities within the industry.
That concludes our formal remarks.
DR. KRESS: We certainly thank you and ask if any
of the committee members wish to ask any more questions.
Any comments from research or NRR? Anybody in the audience
want to make a comment?
Seeing none, I wish to thank the NEI
representatives. We hope you can make our full committee
meeting on the review of the framework document.
With that, I'm going to declare this meeting
adjourned.
[Whereupon, at 3:05 p.m., the meeting was
concluded.]