461st Meeting - April 7, 1999
UNITED STATES OF AMERICA
NUCLEAR REGULATORY COMMISSION
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS
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461ST ADVISORY COMMITTEE ON REACTOR SAFEGUARDS
(ACRS)
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USNRC
11545 Rockville Pike, Room T-2B3
Rockville, Maryland
Wednesday, April 7, 1999
The subcommittee met pursuant to notice, at 1:01 p.m.
MEMBERS PRESENT:
DANA POWERS, Chairman, ACRS
GEORGE APOSTOLAKIS, Member, ACRS
JOHN BARTON, Member, ACRS
MARIO FONTANA, Member, ACRS
THOMAS KRESS, Member, ACRS
DON MILLER, Member, ACRS
ROBERT SEALE, Member, ACRS
WILLIAM SHACK, Member, ACRS
GRAHAM WALLIS, Member, ACRS
MARIO V. BONACA, Member, ACRS
ROBERT E. UHRIG, Member, ACRS. P R O C E E D I N G S
[1:01 p.m.]
DR. POWERS: Let's come into session. This is the first day
of the 461st meeting of the Advisory Committee on Reactor Safeguards.
During today's meeting, the committee will consider the following:
Draft Commission paper on the proposed improvements to the generic
communication process, steam generator tube and reactor pressure vessel
integrity issues, proposed ACRS reports.
The meeting is being conducted in accordance with the
provisions of the Federal Advisory Committee Act. Dr. John T. Larkins
is the designated Federal official for the initial portion of this
meeting.
We have received no written statements or requests for time
to make oral statements from the public regarding today's session. A
transcript of portions of the meeting is being kept and it is requested
that the speakers use one of the microphones, identify themselves, and
speak with sufficient clarity and volume that they can be readily heard.
I'll begin with some current items of interest. One of
those items is that we do have a visitor at today's meeting. Stan
Puchalla is here from the Department of Energy at the request of the
Defense Nuclear Facilities Safety Board to examine how ACRS conducts its
business in the thought that this kind of a structure may be useful to
the DOE's nuclear explosives safety studies. I have welcomed Stan and
suggested that he feel free to buttonhole members, staff and whatnot to
get any kind of information that he wants to have.
Let me also say that we are scheduled on Thursday at noon to
get a briefing on ethics issues, and so Thursday, members should go down
and get something for lunch and get right back up here. You may want to
think a little bit about specific questions that you yourself have on
the various rules and regulations that govern ourselves. I'm sure that
the speaker who's very knowledgeable in that area will begin his
presentation by asking if there are any questions that we have on
individual issues that he can address. He undoubtedly has some prepared
material, but I think he would like to address specific issues and I'm
sure, in the interest of efficiency, we would like to get specific
issues.
With that, I guess we will move to the presentations. The
first topic we're covering is a Commission paper on proposed
improvements to the generic communication process, and Dr. Fontana, I
believe you're the cognizant member on that issue.
DR. FONTANA: Yes. Is NRC staff here to present the
presentations?
Is Mr. Marion here?
MR. BOEHNERT: From NEI?
DR. FONTANA: Marion? NEI?
MR. BOEHNERT: I don't believe so. But he may come later.
DR. FONTANA: May come later.
Are you going to make the presentation?
MR. TAPPERT: I was going to, yes.
DR. FONTANA: Okay.
MR. TAPPERT: My manager is supposed to be here, too.
DR. SEALE: We'll be easy on you until he gets here.
MR. TAPPERT: He'll appreciate it.
DR. SEALE: Then we'll put words in your mouth.
DR. FONTANA: The subject of this discussion is the generic
communications that the NRC uses to communicate with --
DR. APOSTOLAKIS: We can't hear you.
DR. FONTANA: You can't hear?
DR. SEALE: Now we can hear.
DR. FONTANA: Sorry about that.
The purpose of this meeting is to discuss the ff's proposed
revision to NRC generic communications process. The concern is that
these communications -- at present time, there are four kinds that
exist: bulletins, generic letters, information notices, and
administrative letters. The concern is that it's not clearly defined
which generic communication is used for which purpose, and the intent is
to rationalize them and specify what each communication is supposed to
do, and also to make more specific the use of regulatory analysis in
asking for industry responses to these communications.
With that introduction, I would like to turn it over to John
Tappert with the NRC.
MR. MARSH: May I make a few opening comments, too, please?
DR. FONTANA: Yes.
MR. MARSH: Thank you. I'm sorry, I wasn't here when you
started.
My name is Tad Marsh. I'm chief of the events assessment,
generic communications and non-power reactor branch, and good afternoon.
Just a couple opening comments. I think you've already made
most of the things I wanted to refer to before we get started. I just
wanted to highlight that this is a CTM item and we are getting back to
the Commission in short order on what we plan on doing and the results
of our assessment of generic communications.
That paper is due to the Commission coming up next month.
We have -- the draft paper will be discussed in a few minutes by Mr.
Tappert, and we have circulated around within the organization, we've
briefed the executive team, we've gotten some thoughts and comments. So
I did want to leave you with the flavor of a work in progress. It's by
no means finalized, so we certainly appreciate your comments on it.
We've sent the paper and draft form to the -- to NEI and are
going to have a meeting with them sometime after this meeting to get
their feedbacks and comments on it, and the overall thrust of the paper
and of the issue is adding more order and adding more predictability to
the overall generic communication process. Generic communication is one
of most important things that we do. We are sometimes not very rigorous
in our processes for going forward with generic communications, and
we've looked very hard at our goals and objectives and made sure that we
are repeatable and predictable, and we can add some efficiency to the
overall process.
So with that, let me turn to Mr. Tappert and ask him to
present to you the results of our study.
MR. TAPPERT: Thank you.
Okay. My name is John Tappert, I'm the events assessment,
generic communications, and non-power reactors branch in NRR. We're
going to be talking about a draft Commission paper on the generic
communications process right now.
This effort actually started last summer. The genesis was
in response to Congressional interest in us and other external
stakeholders. We had a big stakeholders meeting last July, and also
there was a contentious congressional budget process last year, which
our previous EDO likened to a near-death experience.
As a result of that, a number of items came out of that and
are currently being tracked in the Chairman's tasking memo. Among them
is a review of the generic communications process, and one of the
milestones in that effort is to deliver this paper to the Commission
next month.
The guiding principles for the review were to make it
consistent with the NRC change initiatives to reduce unnecessary
regulatory burden. We wanted to improve clarity, we wanted to make it
more business-like, predictability and efficiency improvements, and also
to try and increase public confidence, if we could.
The paper is still currently a draft. We have four major
issues or opportunities for improvement that we've identified. We're
getting comments every day, so it's a work in progress, but as of April
7th, this is what we have.
We're looking at improving the management of the generic
communications process, clearly defining the products, applying the
compliance succession to the backfit rule and use of information
gathering, particularly use of 50.54(f).
The first thing I wanted to show you was the draft process.
Some of this is already in place and some of it's going to be new.
Before generic communications can be developed, an issue has to be
identified, and this is done by the staff, you know, throughout the
organization, and it's done as a result of operational experience
reviews or other inputs.
Starting last August, the office director for NRR issued a
memo in which he is now requiring an early NRR executive team brief of
emerging issues before significant resources are expended, and that's
just to review and validate the issue before a lot of work is spent.
We've had examples when a lot of work has been expended on efforts that
have to be abandoned because they are not supported by management.
So the issue is identified and it goes to ET. They approve
it for further work or the issue is dropped. The next gate it has to go
through is if the issue is urgent, these are the category 1 issues in
the CRGR charter, which are basically issues that the office director
determines requires immediate resolution for safety or compliance
considerations.
If it is urgent, the net effect of that is to truncate the
preparation time for the generic communication and generally bypass
public comment, and these issues are going to be transmitted through a
bulletin. We expect these issues to be very rare.
If it isn't urgent, then the next step it has to go to is
the staff is going to try and initiate some interaction with industry.
This is a DSI 13 role of industry type initiative. The DSI 13 process
is a work in progress. Currently there's a paper on the initiative with
the Commission.
Basically it outlines a cooperative arrangement where the
agency is going to try and reach out to industry in order to shape and
focus the issue to the benefit of both parties. An effort is going to
be made to try to develop a consensus position for volunteer initiative
by the industry.
If that consensus can be reached, we want to document that
consensus to the use of what we're going to call a regulatory
information letter. This is a new generic communication product; it
doesn't exist right now. I'll get into it later, but basically, in this
context, what we will use to identify the issue, identify what the
consensus position of the agency and the industry us, and provide that
in a public forum, and this would be to support the public confidence
initiatives.
Consensus may not always be reached on these emergent
issues, and if that is the case, then the staff will go back to the NRR
ET and brief them on the results of the interaction with industry,
providing the two positions. If the agency decides to go forward, we
will use a generic letter, and that will go through the public comment
process and CRGR reviews and the like, or the agency may decide to
pursue other issues.
DR. APOSTOLAKIS: Well, this seems to evolve around from
issue-specific actions, but I was reading the Senate -- I don't know
what document it is, but where there is a complaint that the NRC
frequently imposes regulatory requirements using informal approaches to
circumvent legal
requirements. This seems to be a broader complaint. I mean, you don't
have to have a specific issue, and what comes to mind, and this
committee has commented on it, is the use of core damage frequency goal
of ten to the minus four, which sort of de facto became something that
the staff has been using when, in fact, there was not a proper process
followed to make it a part of the regulations.
So how would that be related to an issue? I mean, you don't
have to identify a specific emergent issue to worry about all this -- I
mean, the concern seems to be broader than this. Are you addressing the
broader concern or just --
MR. TAPPERT: We're looking at the generic communications
process. I mean, if you're worried about positions being imposed
through other means, we're not addressing that in this paper. We're
trying to put more discipline into the generic communication,
specifically generic letters and bulletins, into that kind of process.
We want to put screenings and controls and checks and balances on that.
We're not really taking on anything larger than that.
DR. APOSTOLAKIS: And the Commission specifically asked you
to do this?
MR. TAPPERT: That particular item in the Chairman's tasking
memo was to review the generic communications process.
MR. MARSH: One of the thoughts that's in some of this
Senate comments and also the stakeholder comments was the informality of
the generic communication process; that is, perhaps you're relying on
the exemption associated with compliance backfits, and that was a pretty
major issue and we're going to talk more about that today, or the use of
information notices improperly or the use of -- the unclarity of the
generic communications themselves, what category of issue or response do
you use generic letters and bulletins and things of that sort.
We're not taking on the broader issue -- CALs, for example,
the use of confirmatory action letters. There's another criticism the
industry had about imposing requirements on licensees through the CAL
process. That's another vehicle.
This is confined to just the generic communication part of
the -- that was what we were tasked to do through the CTM process. I
think you're going to hear more structure and more formality in the
formation of these documents as we go through, especially in the
compliance backfit. There's some very interesting background
information that we've been able to get through reviewing the statement
of considerations.
DR. POWERS: I agree that in your document, one of the
things that come through is a much more disciplined process.
MR. MARSH: Right.
DR. POWERS: There's a puzzling feature of this particular
graph here. It begins with staff identifying an emergent issue. It
goes through a review and then we begin a series of steps, and it might
end up being a bulletin issued, but in general, that would be unusual.
More usual, it would come down to the step that says staff works with
industry, and the question posed, is there a consensus or not, and it's
not uncommon for there not to be a consensus, though in recent years,
there seems to be a lot of consensus. But -- and then we come down to
another review that can result in dropping the issue.
You, I don't understand how failure to achieve consensus
with the industry would change the decisions made at the top of that
that this was indeed an issue.
MR. TAPPERT: Well, it doesn't change that decision and, of
course, you'd issued the generic letter. But it is possible that
through the working with industry, even though you haven't achieved
these consensus, you have developed additional information that leads
you to conclude that it's not necessary to pursue that issue any
further.
DR. POWERS: It seems to me that would be a consensus, then.
I mean, if you got -- if industry got together and said, hey, we don't
think there's an issue here because of this and this and this and this,
and you guys said, oh, merrily, that's true, then you achieve consensus.
MR. TAPPERT: That would be a consensus, but potentially --
DR. POWERS: I think this sends the wrong message here that
--
MR. TAPPERT: Right.
DR. POWERS: -- if I don't achieve consensus, then I'm going
to drop this issue, and I think that's not the kind of image that you
want to portray --
MR. TAPPERT: Yes.
DR. POWERS: -- to the public. Maybe this is not what you
intended these words to say, but that's what these words say to me.
MR. MARSH: I think that's a fair thought. The idea is to
work with the industry in a very linear way in almost all of these
concerns and find out where are we in terms of initiatives that are
going on. But it's not meant to just drop them if consensus is not
achieved.
DR. APOSTOLAKIS: I suspect that the word consensus there
refers to the members of the staff who worked with the industry, and
these are not the same as the NRR ET, are they?
MR. TAPPERT: Correct.
MR. MARSH: That's true.
DR. APOSTOLAKIS: Okay. So there was no consensus at that
level, then somebody else reviews it, gets convinced by the industry and
drops the issue.
MR. MARSH: Right.
DR. APOSTOLAKIS: But you are sending the wrong message.
DR. POWERS: I think this -- I just think that this is --
MR. MARSH: That wasn't the intent of the slide.
DR. POWERS: -- not the intent. It can't possibly be the
intention.
MR. MARSH: It's not.
DR. POWERS: Okay.
MR. MARSH: We'll work on the words or work on a feedback
arrow or something to imply that it's -- no consensus equals --
DR. SEALE: It's an invalid issue rather than drop the
issue.
MR. MARSH: Or that there have been -- other vehicles have
taken care of it.
DR. POWERS: I think you can come down here and say, issue
resolution, yes or no. If it's no, then you go to a regulatory
information letter. If it's yes, then issue conclude -- issue is
resolved.
MR. TAPPERT: Yes, but -- yes. Clearly the intent is not to
walk away from a safety issue just because there's no consensus.
And the next slide I think should be basically what I just
said. Yes, we say if there's an impasse, ET will be briefed and a
generic letter may be authorized.
One of the other issues we had when we're talking to the
stakeholders is there appeared to be some confusion between the product
line that we currently have. There was some confusion between the use
of bulletins and generic letters. Some of that may be some legacy
issues. The old Office of Inspection and Enforcement used to issue
bulletins, and the Office of NRR used to issue generic letters and then
they were combined and now we issue both. Bulletins currently are
typically short-term urgent-type issues and generic letters may be
longer-term programmatic type issues. But generic letters also can be
used for a whole host of other things. The provide new staff positions
and can offer regulatory relief or they introduce new tech spec line
improvements and things of that nature.
So we try to develop a new set of generic communications
building on what we have to try to make some of those lines a little bit
more crisp, and what we have is before you. Basically, we want to use
bulletins -- we're going to use them to request action and/or
information, but it's only going to be used for urgent or category 1
type issues. These are the truncated issues that are going to bypass
public comment. They will, of course, be reviewed by CRFR and we'll
typically invoke 50.54(f) for their information requirements.
Generic letters, on the other hand, --
DR. POWERS: It seems to me that this --
MR. TAPPERT: Yes, sir.
DR. POWERS: -- decision that you have between bulletins and
other kinds of communications hinges crucially on the decision of
whether it's urgent or not, and I guess I'm asking how do I go about
deciding whether something is urgent or not?
MR. TAPPERT: The urgency is basically the decision of the
office director with the support of the staff. But there are issues
that require immediate resolution for safety or compliance
considerations. The last one that I recall would be we had some issues
a couple years ago about control rods not fully inserting during SCRAMs.
That was considered a bulletin type issue. Most things are not.
MR. MARSH: The past is not a very good reflection of this
type of differentiation at all. We've had situations that have been
issued as bulletins and bypassed the public comment period, and on
reflection, this was not the appropriate thing.
Risk is an element that needs to be mentioned here, too, if
there is safety or risk considerations or strong compliance issues. The
thrust here is to reserve bulletins for the smallest set of issues that
are there and not to over-use them.
DR. POWERS: What I see is this problem. I mean, your
document is trying to set up some sort of discipline in --
MR. MARSH: Hierarchy.
DR. POWERS: -- this process, and I have an office director
today and he has one set of views on what's urgent, but there's some
turnover in this organization, and so tomorrow, I may have a different
guy with a different set of views on what's urgent or not.
Meanwhile, there's an industry out here that is seeing what
to them looks like an inconsistency coming out, and I'm wondering if you
don't have to go in and at least provide some guidance in the form of
examples and maybe more explicitly on what you mean by urgency so that
the outside viewers don't see this thing as changing from one day to the
next.
Now, I will agree, there's going to be some change, but it
should not be see change, which right now, with just, this is urgent or
not, you could have that see change.
MR. TAPPERT: Yes. Currently, I think the only guidance is
in the CRGR charter, which defines these category 1 issues. The idea is
to have a very high bar, and --
DR. POWERS: But you need to get that across because it does
not come across in your existing document, at least it didn't come
across to me.
MR. MARSH: Do you think that by referring you back to the
charter, the CRGR for category 1 items, that that language doesn't make
it clear enough?
DR. POWERS: I don't think that. I think that you need to
make it -- yes, I think the best possible thing is if you can say,
urgent means urgent and here's an example.
MR. TAPPERT: That's fine. I was hoping you would not ask
us to put something quantitative --
DR. POWERS: No, no. I think that would be difficult to the
extreme.
MR. TAPPERT: Right. Right.
DR. POWERS: I think imparting what you mean by urgent, and
if you can pluck out an example from the past whether you think it was
appropriate --
MR. TAPPERT: Okay.
DR. POWERS: -- and maybe if nothing else, anecdotally you
can not write in the document, but anecdotally, you can say, and here's
one example of something that's not urgent.
MR. TAPPERT: Okay.
DR. POWERS: Because I think there's going to be a
subjectivity here that we ought to allow. Otherwise, we get robots for
directors.
MR. TAPPERT: Right.
DR. MILLER: I have a couple of questions on what you say on
this overhead.
MR. TAPPERT: Sure.
DR. MILLER: And maybe you're going to address them later.
If you are, just tell me to hold off.
On bulletins, it says "may invoke 50.54(f)." On generic
letter, it says "typically will not invoke 50.54(f)." And under
regulatory information, it says "CRFR will review as needed," and the
other place, it says, "may when appropriate." Now, all those seems like
waffle words to me; all could be the same in the end.
MR. TAPPERT: Right.
DR. MILLER: So is there a criteria on which those decisions
are going to be made or some judgment, or who is going to do that?
MR. TAPPERT: Well, the criteria on the backfit rule is a
lot clearer, you know. Anything that could potentially be interpreted
as posing a new requirement --
DR. MILLER: I agree. Yes.
MR. TAPPERT: The question of 50.54(f), which is a
requirement that allows the NRC to go out and demand information from
licensees to make a determination whether to modify, suspend or revoke
their license, that's an issue that's currently under active discussion
in the staff right now.
DR. MILLER: Why does that appear under, say, bulletins and
generic letters both?
MR. TAPPERT: Currently, --
DR. MILLER: What's the difference between typical and not
invoke and may invoke?
MR. TAPPERT: My expectation would be that it would in
bulletins under all circumstances and generally would not in generic
letters. But there may be exceptions, and --
DR. MILLER: So generic letters usually would not, --
MR. TAPPERT: I would think --
DR. MILLER: -- bulletins usually would or --
MR. TAPPERT: Yes.
DR. MILLER: Okay.
MR. TAPPERT: But there may be exceptions. I mean, I could
say always and never, but that may not be appropriate, and we may change
our position on that as well.
MR. MARSH: The general idea here is again to avoid the
over-use of the 50.54(f), which was the traditional language which was
included in almost all of these. That was a specific comment that we
got from our stakeholders.
DR. MILLER: Isn't that not only a lot of the comments,
isn't that what the allegation or implication was -- you were invoking
new requirements came through that one?
MR. MARSH: I don't believe that was the thrust. I believe
the thrust of the concern was, 50.54(f) language is pretty strong
language, okay? It says, we're thinking about taking your license away,
okay? And that's not really what we meant in these generic
communications. It wasn't imposing any new requirements; it's a big
hammer that's not appropriate for the type of communications being
conveyed, whereas in the bulletin, it may be appropriate, and that's
what we mean by, you would expect the small set of generic requirements
about which you have the highest safety significance to issue the
strongest language that you need to imply the agency's concern, whereas
under generic letters, where you're not as concerned, you don't need and
should not use that type of language.
The concerns that we've heard from -- John, I'm probably on
your territory here, but we heard that industry, utilities would get
these generic communications with this language in it and it would
impart a special priority and a special emphasis and would dictate their
actions, their scheduling, their resource allocation to the exclusion of
other things, and it was not the appropriate emphasis.
I know what we had done in the days of old, we thought
50.54(f) was the appropriate language; it was the legality that we were
adding to these communications. We thought this was the way to do that.
We used to have just generic letters, and we would just write licensees
letters without there being any legal stamp to them. And so in days of
old, we would say, we better put something legal associated with this.
What's our vehicle? Ah-ha, 50.54(f), without really looking at the
language that was being used in the regulation itself.
DR. POWERS: I think what you looked at was the language
that begins the paragraph, --
MR. MARSH: Right.
DR. POWERS: -- which says you can require information of
licensees anytime you want to, and not the closing paragraph, --
MR. MARSH: Which is the strongest possible language.
DR. POWERS: -- which says that we're thinking of changing
and modifying your license, and that looked like a blunderbuss --
MR. MARSH: Right.
DR. POWERS: -- to the industry as a whole because that
language looks like it's directed at an individual licensee, whereas the
generic letter is obviously going to all of them.
MR. MARSH: Exactly. Exactly. That's what we're trying to
remedy here by not using that language unless you absolutely mean that.
That's the deafferentation that we're trying to impart here.
DR. MILLER: So somebody will make -- or somewhere along the
-- you make that decision --
MR. MARSH: Yes.
DR. MILLER: -- absolutely.
MR. MARSH: Yes, sir.
DR. MILLER: And that's a decision -- is that part of the
decision tree back there?
MR. TAPPERT: The 50.54? That's not explicit.
DR. POWERS: You also have to understand, there's -- in
50.54, the licensee is required to respond under oath.
MR. MARSH: Right.
DR. POWERS: And that's an imposition on the director of an
operating entity when he's being asked to collect a bunch of information
that's done at lower levels, and then he has a major problem of QA/QC --
MR. MARSH: Right.
DR. POWERS: -- that he's got to impose, because he goes to
jail if they screw this up, and when, in fact, the agency may be just
asking for --
MR. MARSH: Right.
DR. POWERS: -- something of a fairly low significance
relative to that oath.
MR. MARSH: Right.
DR. POWERS: And so you can appreciate the headache that
this language might impose when, in fact, all that was done, you're
saying, yes, we have a right to ask you for information.
MR. MARSH: Exactly.
MR. TAPPERT: The difference is in the bulletin. Generic
letters are consistent with the concept of a very high bar for the
bulletins, and those have been the issues with the 50.54(f).
Moving on to the generic letters. These will also request
action and/or, you know, request a response, but they will never be
urgent. And so we're drawing that line. The bulletin's urgent; generic
letter is not urgent.
A new requirement on generic letters, well, they cannot be
issued without a prior attempt to work with the industry, okay? And
that currently isn't the case. Will always be issued for public
comment. Will always be reviewed by CRGR against the backfit rule.
DR. POWERS: Let me ask you --
MR. TAPPERT: Certainly.
DR. POWERS: A favor. Typically when you produce these
generic letters, we're offered the opportunity to review them both
before and after public comment. And we've been incredibly quixotic
about whether to do it before or after or both. I mean, I could
appreciate the staff if they came in and said we haven't got a clue how
to schedule our time because we don't know whether you're going to
review before, after, or both.
MR. MARSH: Right.
DR. POWERS: And one of the things we want to struggle with
is as an institution ourselves and in the spirit of getting a little
more disciplined in this process have ourselves some criteria for
whether we review before public comments or after public comments.
I wonder if you and your staff could give this half an hour
of thought and see if you can come up with some criteria by which we
could decide whether to review before or after.
MR. MARSH: Okay.
DR. POWERS: Understanding it comes from your perspective.
But I think that would help us a lot, and it offers you the opportunity
to at least anticipate for your own scheduling purposes.
MR. MARSH: Sure. Be glad to.
DR. POWERS: Whether we review before or after. We're going
to be looking at it and thinking about it ourselves, but I think we
would really appreciate your views --
MR. MARSH: Sure.
DR. POWERS: And maybe between the two of us, we can come up
with something that there is a mutual understanding in the scheduling
that this is going to be done afterwards versus how the one's going to
be done before.
MR. MARSH: Sure. Be glad to.
MR. TAPPERT: Okay? I guess the next product is something
new that we want to introduce, and that's this regulatory information
letter. As was mentioned before, currently generic letters have a
number of functions that do not require a response, and we'd like to
roll these into a new kind of product.
You know, we've used them to transmit NUREGs or transmit
inspection guidance like the operability determinations in 91-18 and
things like that. And those types of things are very important to
communicate to the industry, but we wanted to put them in a different
kind of vehicle that would not -- which they would know right from the
get-go that there's no clock running on when they have to respond to it.
DR. MILLER: So, in the old days, generic letters would have
done some of these items. Right?
MR. TAPPERT: Certainly. Right.
Yes, it's going to capture a lot of the old generic letters.
So we expect the number of generic letters to go down, for a couple of
reasons. One, we're excluding all these policy-type issues, and also
we're going to attempt to work with the industry more and maybe head
some of these things off.
And that's the use that we want to use for these new
regulatory information letters, is to document the consensus positions
that are arrived at some of these emergent issues that we've had off
other generic letters.
And also we're going to eliminate administrative letters,
which are kind of muddles sometimes, and we're going to capture those
types of things in this as well.
CRGR review will be as needed, depending on what type of
things, if we're putting out inspection guidance or reg guides or things
like that, typically CRGR reviews those types of things.
DR. MILLER: There's a pretty defined criterion when CRGR
has been written.
MR. TAPPERT: Correct. And that's not going to change. And
some of these will fall within the purview of their charter, and
therefore will be reviewed.
And then finally we're going to keep information notices,
and basically these are just going to provide information that's derived
from operational experience. There's no requirements. It's just for
information to help licensees perhaps avoid similar problems at their
facilities.
DR. BARTON: I notice that information notices aren't
included in your flow chart on how you're going to process generic
communications, and is that just an afterthought or oversight, or don't
you need to go through this process to decide whether what you want to
put out eventually is an information notice?
MR. TAPPERT: Right. An information notice is a little bit
different in a number of respects. The resources associated with
developing and issuing an information letter are much less than a
generic letter or a bulletin.
DR. BARTON: I understand that.
MR. TAPPERT: We're not going to the executive team to talk
about ideas we have for information notices. We're handling that at the
branch level. And so that's really a different track.
MR. MARSH: Just with one caveat I'd like to add to that, to
the information notice. Sometimes information notices touch subjects
that are very sensitive.
DR. BARTON: Um-hum.
MR. MARSH: Like sometimes in the fire-protection area they
touch sensitive subjects, and so the ET does want to be briefed on
issues that in the judgment of the line organization or the division
directors or myself as a branch chief in this branch need to bring up to
the ET if they touch those subjects. It's a subjective area, and you
don't want to impart rules for that, but it relies on judgment of
ongoing issues.
MR. TAPPERT: Historically we've had some information
notices that have tread very fine lines to developing new policy
positions or transmitting new technical policy positions.
DR. POWERS: Especially in fire protection.
MR. TAPPERT: Right. Exactly.
DR. POWERS: Fire protection is the --
DR. MILLER: Actually there's a generic letter and an
information notice that really address the same issue and said similar
things.
MR. TAPPERT: Yes. And information notices really shouldn't
be used to transmit that type of stuff, and with this new regulatory
information letter we won't have to. You have a new vehicle. People
have been shying away from generic letters because they've been -- the
significant resources associated with those. And we're trying to kind
of split the difference with this reg info letter.
DR. FONTANA: With respect to your information notices, on
page 7 of the draft SECY it says information notices may not convey or
imply new requirements, blah blah blah, and may not require or request
specific actions.
Shouldn't that "may" be "should" or "shall" not? Because
you have other things that may or may not, but the impression I got from
reading this, that information notices would not convey new requirements
or request specific actions.
Did I read that properly?
MR. TAPPERT: They do not and should not, will not, they
shouldn't.
[Laughter.]
MR. MARSH: We'll fix that.
DR. BARTON: Yes, your words in here are kind of wuzzy,
though. You say you may. So that leaves it open.
MR. TAPPERT: Okay. May not means they may not, to prevent,
to preclude.
MR. MARSH: We'll make it clear for you. We don't want to
leave an open door for this one.
DR. SEALE: Yes. Some wills.
MR. MARSH: Right.
MR. TAPPERT: And the thing about the information notices,
since there are no new staff positions, signature review is not required
for those documents.
There have been some comments about the names. They may
still be confusing. We have information in two of the things. We have
letters in two of the things. So the names may change, but that's
basically the outline of the products that we're trying to go forward
with.
Another concern which was raised by the stakeholders was
generic backfitting through the use of generic communications and other
items I think somebody raised, that there's broader issues. Other
efforts have looked at confirmatory action letters and requests for
additional information which were also candidates for improper
backfitting, which are being addressed by other people during other
efforts, but we were looking at the generic communications aspects of
it.
And just by way of background, bulletins and generic letters
are not backfits, because they don't technically impose any
requirements. Only orders and rules do that sort of thing. But for
pragmatic reasons, licensees feel a very strong obligation to respond
and conform with these generic communications. Therefore, we have
procedures that treat them as if they were backfits. And that's the
CRGR process, to ensure that they're all in compliance with the backfit
rule.
The backfit rule does require a value-impact assessment for
all backfits except for purposes of compliance for adequate protection.
However, most generic communications do invoke this compliance exception
to the backfit rule, and as a consequence, they do not do these
value-impact assessments.
There were repeated criticisms by the industry of this
practice. Many times they take exception with our interpretation of the
compliance exception.
So we took a look at this issue again, and what we thought
would be most appropriate is to perhaps work with the industry to try
and develop simplified analysis techniques to evaluate values and
impacts for actions even when the compliance exception is invoked. So
even though the compliance exception is invoked and you don't have to
demonstrate the substantial safety benefit with justifiable cause, it
seems to us to be appropriate to at least have a qualitative view of
what the costs being imposed are and what is the expected benefit of
that.
So rather than compliance at all costs, we find out well,
what is the cost of compliance, and is that appropriate. And the reason
for doing that simplified analysis is just to provide additional
information to the decision makers when they make the decision to issue
that generic communication.
DR. POWERS: I would think that you would run into legal
barriers here. It seems to me that you're bordering on using cost in a
decision making process dealing with adequate protection, and it's being
done by subterfuge here. Have you run into any legal concern over this?
MR. TAPPERT: Cost -- adequate protection is clearly
addressed in the backfit rule, and, I mean, yes. Adequate protection
backfits cannot consider cost and must be imposed. There's no ifs,
ands, or buts about it. If it's an adequate-protection issue, it has to
be imposed.
The problem is with compliance issues, okay? It doesn't say
that about compliance issues. But compliance issues can be imposed
without doing a value-impact assessment. And we say well, let's just do
a limited one to try and get a qualitative feel for what the costs and
what the benefits are. Maybe the generic communication is the wrong
vehicle. Maybe we need to change the rule. Maybe we need to grant
relief. There might be other avenues to pursue.
But the idea is just to have additional information rather
than you have the issue, you determine its compliance, stop. We say
well, don't stop there, take the next step, you know, and understand
what you're doing.
DR. POWERS: I guess I'm perplexed a little bit.
MR. TAPPERT: But not for adequate protection.
DR. POWERS: If I define adequate protection as compliance
with the regulations, why is a compliance issue not part of adequate
protection?
MR. TAPPERT: I don't think they're necessarily synonymous.
DR. POWERS: And I guess I'm asking why do you think that
they're not synonymous.
MR. TAPPERT: I guess I don't have a real good answer to
that, except they always are addressed as two separate categories, you
know. The backfit rule talks about safety enhancement backfits, it
talks about compliance backfits, and it talks about adequate protection
backfits. If they were synonymous, there would be no reason to talk
about the two different types. They further go on to discuss the fact
that adequate protection backfits must always be imposed. It doesn't
say that about compliance backfits. So there is some subset of issues
that speak to compliance with rules but do not reach the threshold of
adequate protection.
There are rules, talking to some of our OGC friends, there
are rules that are adequate-protection rules and there are rules that
are safety-enhancement rules. Compliance with a safety-enhancement rule
would not fall within the purview of an adequate-protection backfit.
MR. MARSH: I'm not sure -- we're trying to answer your
question; I'm not sure we're --
DR. POWERS: Yes, I think we'll both concede that you need
to think about this one a little bit.
MR. MARSH: Yes. I mean, you could -- Com SHA and the
Commission has said that you can be in compliance with the regulations
and still not meet the adequate-protection criteria. There may be
issues which you must impose new requirements. You can still be in
compliance, but there's something inadequate about your regulatory
framework such that you must impose a new requirement. That's an
adequate-protection type of threshold. Absent any problems with the
regulatory framework, compliance should assure adequate protection.
DR. POWERS: Compliance means -- it's presumptive that if
you're in compliance --
MR. MARSH: It is presumptive.
DR. POWERS: It is adequate for protection.
MR. MARSH: Yes, sir.
DR. POWERS: The inverse and the converse of those
statement --
MR. MARSH: May not be true.
DR. POWERS: No one said anything about them.
MR. MARSH: That's right.
DR. POWERS: Okay.
MR. MARSH: Right.
DR. POWERS: And so I agree, it is conceptually possible to
be out of compliance but still have adequate protection.
MR. MARSH: Yes, sir.
DR. POWERS: Conceptually.
MR. MARSH: True. And you could be in compliance and not
have adequate protection.
DR. POWERS: And similarly you can be fully in compliance
and not have adequate protection.
MR. MARSH: True.
DR. POWERS: Okay.
MR. MARSH: True.
DR. POWERS: Because it's only a presumption.
MR. MARSH: True.
DR. POWERS: And it can be disproved by evidence.
MR. MARSH: And the Commission has said that.
DR. POWERS: Um-hum.
MR. MARSH: In their --
DR. POWERS: And I agree with that.
MR. MARSH: And it makes sense. We have on various times in
the past imposed new requirements because we felt the regulations were
not sufficient, again the station-blackout rule, where we had to change
the regulatory framework because it didn't address problems adequately.
The thrust here is to address the concern which we feel has
legitimacy, that is add order to your process first. Some of these
compliance backfits are not well thought out on our part and we want to
do a better job at the compliance backfits. Now how do we do a better
job?
All the way through that chain it is working through the
industry. Improve the dialogue. Find out what programs are ongoing
with the industry. How can they be addressed? -- which may obviate
ways for you to even issue a generic communication in the first place.
That is the more preferable route.
If a generic communication is needed, that second part of
the line, then be very careful about the basis under which you are
proceeding. Don't rely exclusively on this compliance backfit without
understanding what it mean. I mean that is useful information -- if not
bases for the decision it's decision-making information.
DR. POWERS: I think you need another paragraph in the
document that makes it clear that when you do this mini-value impact
assessment that it is being done on a compliance issue and not an
adequate protection issue.
MR. MARSH: Fair.
DR. POWERS: And that what its intentions are and this
distinction that you have drawn between compliance and adequate
protection, just to cover yourself on a legal standing.
MR. MARSH: Fair.
DR. POWERS: I think the overall strategy that you are going
to place a step in here that requires some communication with the
industry to assure that you are not operating based on a misapprehension
or not fully aware of all of the things that the industry has done may
mean that this concern is strictly one of legal theory and not of
practicality, but I think I would worry a little bit about the legal
theory here.
MR. MARSH: There will be others which will come after us
which will look at this and if it doesn't have the adequate framework --
and the paragraph you are suggesting is consistent with what we have
found from going through the statement of considerations and the backfit
rule too.
MR. TAPPERT: The original backfit rule was thrown out for
that very reason.
DR. POWERS: That's right.
MR. TAPPERT: Because you cannot consider cost radical
protection issues and that was always the intent of what we were
discussing as well.
DR. POWERS: I understand.
MR. TAPPERT: That is our discussion of backfit. Does
anyone have any questions? Okay.
There is another ingredient here that we didn't bring up in
the letter. We weren't sure whether it should be brought up in the
letter but it has to do with how we are going to do these backfits
within the organization.
There is oftentimes a reliance on compliance backfit because
there is a reluctance to do this cost benefit study and so if you
interpret the regulation one way you can avoid doing a lot of work.
What we are trying to say -- we want to do this limited cost benefit
study pretty routinely and organizationally we want it to be done in one
place rather than have it be done by different organizations and lose
consistency and have it be a burden beyond the technical issue that is
involved, so we are going to centralize where those backfits -- where
those analyses will be done.
The last item that we discuss in the papers is information
gathering, particularly the use of the requirement 10 CFR 50.54(f) which
requires licensees to respond with their affirmation to enable the
Commission to determine whether or not the license should be modified,
suspended or revoked.
We got some stakeholder comments that they thought that this
was a little heavy-handed, that it was disproportionate to the needs for
that information and that it was having an officer of a company sign
something on their oath or affirmation really didn't change how the
agency would use that information.
If we did not cite that requirement, is it credible to
assume the licensees will response to the due diligence and I think of
course it is. They would respond, I believe.
DR. POWERS: I mean they are still required for due
diligence. All you are eliminating is the affirmation part.
MR. TAPPERT: Right. There's other requirements -- 50.9
requires complete and accurate information in all material respect.
DR. POWERS: Right.
MR. TAPPERT: And that was still the reply.
DR. POWERS: That seems to be the most powerful argument
that you have here is that the licensee still has a very real incentive
to do the best job he can on that.
MR. TAPPERT: And there's other -- the Office of Management
and Budget also has requirements that they place on Federal agencies to
justify all information requests, and every year we have to go out and
justify an OMB clearance number, which is also required in all these
generic communications. That puts additional controls on how we do
these things.
DR. POWERS: That's kind of an effete -- I mean right now
you have got kind of a blanket clearance from OMB on this one, so yes,
it exists but it is more in principle than in fact.
MR. TAPPERT: But in theory it is another control on these
type things.
The proposal in the paper right now, you know, subject to
change, is to really limit the use of this, citing this requirement to
really the very high threshold issues. We were thinking maybe just
eliminate the bulletins. Maybe that is not -- then there might be some
subset of generic letters which also would be appropriate to use that
and we are still kind of hashing that out.
Other people have suggested perhaps just tailoring the
language or maybe changing the language in 50.54(f) to make it clear
that we are really not talking about revoking the license. At worst we
are really talking about potentially an order, depending on what we get
back from you or a modification to the license.
Finally, 50.54(f) in addition to providing this authority to
demand information from the licensees also puts a requirement to the
Staff to evaluate the burden imposed and justify it in terms of the
safety significance of the issue, of the information of the issue that
you are getting information on.
That analysis needs to be done also but there is an
exception to verify compliance again with the licensing basis. We feel
that that standard would still be an appropriate standard to use, even
if you don't invoke the requirement itself.
In a nutshell, that is basically what is in the paper.
That's all the slides we have, so if there's any other questions --
MR. MARSH: Should this pass the test of going through our
management processes and being acceptable, then there is a lot more work
to be done to implement this and there's issues about things that are in
process already -- at what point do you make them fit into the new
regime?
There's office letters which will need to be modified to
implement the new procedure as well, and associated with the CTM and
telling the Commission what we intend on doing there is a communication
plant too, now we intend on communicating this new process to the agency
and to the staff, so there's a lot more work associated with this new
concept.
Again, the thrust is to make it a better process, to more
clearly define these vehicles, these communications, and to add some
order to it.
If one looks back on the past generic communications,
there's more examples of imprecision than I think of precision,
unfortunately. We all have those specifics in mind, I'm afraid.
MR. BARTON: It definitely seems like an improvement.
MR. MARSH: Thank you.
DR. POWERS: Let me see if I can understand a little bit,
make sure I understand the difference between a regulatory information
letter and an information notice.
My understanding from what you have said here is that
information noticae -- notices -- will be attempting to capture
operational experience and will be more under the control of Branch
Chiefs rather than this overall process, that there will be some effort
to inform the ET, some effort to inform you, but otherwise they are kind
of freer?
MR. MARSH: They go through our branch.
DR. POWERS: Through your branch.
MR. MARSH: All the information notices go through our
branch. They are issued by either myself or through the Division
Director, but they all go through us.
DR. POWERS: So they are capturing operational experience?
MR. MARSH: Normally. That is the norm and that is the
thrust at this point. It is normally LER driven, 50.72 driven. It's
experience as you see it come through that you want to collect and you
want to hold up to the industry as being -- gosh, there's been three or
four situations like this -- for your information -- no action needed.
Look at this. That is what it is intended to do.
MR. TAPPERT: Plant X and Y had Problem A.
DR. POWERS: Sure. I mean we have seen them and they are
very useful actually.
MR. MARSH: They impart -- we have been asked why are you
issuing information notices when the industry has issued an LER or a
50.72. You are trying to share information to the industry -- isn't
that good enough? Isn't an LER good enough? And the answer to that for
me is no. When the agency gathers together two or three events and puts
an agency perspective on it, without it being a new requirement, it is
different. It sets it up higher and it is not -- LERs are normally the
licensee's spin on an event. It is how they see it with their
perspective.
Sometimes you need to convey it in a different way.
DR. POWERS: I think it can be critically argued that a
lesson that we got out of the events at Davis-Besse versus TMI was that
there are issues that are a little higher than just the LER and that it
does behoove everyone, even if everyone in the world knew it, to put it
down on a piece of paper that says, yeah, we all know this.
MR. MARSH: Absolutely.
The regulatory information follows from your network and
whatnot, and so it has more of a total management chain and a broad
field of coverage.
MR. TAPPERT: Right. It also covers other types of things.
DR. POWERS: Sure.
MR. TAPPERT: That is our catch-all now.
DR. POWERS: That will be the most common communication of
the three top ones.
MR. TAPPERT: Yes.
DR. POWERS: Yes.
MR. TAPPERT: The expectation anyway. You know, this is a
conceptual, this is a plan. We are trying to move forward and do
better, but, you know, a lot of things are still being developed. The
DSI-13 framework, it has been sketched out, but all the details haven't
been filled in, and that is the key component of what we are talking
about here.
MR. MARSH: John, would you hold up the charcoal filter
generic letter as a letter which at least has in it this qualitative
value impact study?
MR. TAPPERT: It has been a while since I read that. I
think we did have some discussion of benefit and some -- I don't know if
there is any cost information in there or not, I can't recall.
MR. MARSH: Yeah, I think there is some cost information.
It was thought to be a compliance backfit.
MR. TAPPERT: Right.
MR. MARSH: As it went through the system, the first thing
-- the first change to that generic letter was let's purge the 50.54(f)
language out because -- to embrace what we are talking about here, and
also to do some limited value impact. That means to provide the
decision makers with what are we talking about, what is the cost and
what is the benefit, even though we thought it was a compliance backfit.
MR. BARTON: Attachment 1 to your draft SECY had a block on
there for ACRS briefing for bulletins, Generic letters or the new
information letter, and it said upon request. Wouldn't ACRS want to
review all bulletins?
MR. TAPPERT: I think that is the current guidance, is that
you have the -- you can request. We offer to brief you on any of these,
and if you choose to have that briefing, we will certain conduct it, but
I think it is on an ad hoc basis right now. It is not 100 percent, is
it?
DR. POWERS: I think we get noticed on -- I think you let us
know about everything.
MR. TAPPERT: We let you know about everything, but you
don't necessarily get briefed on everything.
DR. POWERS: That's right. We pick and choose and that --
and, as I said, our picking and choosing is sometimes quixotic.
MR. TAPPERT: Would you like some suggestions?
MR. BARTON: Well, I can see when, before public or after
public comment.
MR. MARSH: Right.
MR. BARTON: This looks like, you know, we would have to
request a briefing.
DR. POWERS: I think there is a memo of understanding.
MR. BARTON: Okay.
DR. POWERS: That it is not like we have to have a spy to go
find out about it. They let us know that they are doing this.
MR. MARSH: Right.
DR. POWERS: And then we put it through our P&P process and
if we choose not to, we send them a Larkins-gram, a memorandum that says
we are not going to review this or we are not going to review this till
after public comments, or we are going to hear it by what.
MR. BARTON: Okay. If you feel it is adequately covered,
that is fine.
DR. POWERS: And what I want to do is try to put -- give us
some guidelines which, in turn, turns into guidelines for you so that
you can better anticipate what we might do.
MR. MARSH: Right. Sure. We will be glad to do some
thinking on that, but there are some natural divisions that we have --
which would probably guide you, too, I would think. Is it of high
safety significance? You would want to be briefed.
DR. POWERS: Well, I am sure that we would look at
bulletins.
MR. MARSH: Right.
DR. POWERS: Even though they are on an urgent pathway, and
we won't be in the -- we won't be on that pathway, but we will do them
in parallel.
MR. MARSH: Right.
DR. POWERS: I am sure that generic letters will still
attract our attention.
MR. MARSH: Right.
DR. POWERS: I suspect that regulatory information letters
based on mutual interest and things like that. But, no, I am just
trying to get some of the standardization here. I am just following
along exactly your plan, put some discipline and a little better
anticipation.
MR. MARSH: I would be glad to. Sure.
DR. FONTANA: Any additional questions of Mr. Tappert or Mr.
Marsh?
DR. WALLIS: I have had a question all along, which I have
wondered if I should ask.
DR. FONTANA: You don't have to.
DR. WALLIS: What is the role of the ACRS in all this? It
seems to me there is something that needs to be done, and the staff can
work it out with industry. What are you expecting us to do? Or what do
we expect to contribute to this issue, or these activities?
DR. POWERS: Well, I can tell you historically that there
have been one than one issue where we have been instigators of generic
letters, and been more than one instance where we have said this is a
non-issue, why are you pursuing it?
DR. WALLIS: That's right. Is this some issue which
requires us attention, that we can help to resolve? I can't sort of
figure out what is.
DR. POWERS: Well, if it is a bulletin, I guarantee you it
gets our attention, because it is a bulletin, by definition means that
there is some reason that the plants --
DR. WALLIS: So we need to know what is going to on in case
something might come up.
DR. POWERS: Sure.
DR. WALLIS: Okay.
MR. MARSH: Okay. Thank you very much.
DR. FONTANA: Okay. Thank you. NEI has requested time to
make a presentation. Alex Marion.
MR. MARION: Thank you. I don't have a presentation, but
there are a couple of comments I would like to make. My name is Alex
Marion, I am the Director of the Programs Department at the Nuclear
Energy Institute, and I thank you for the opportunity to chat with you
about this generic communication process.
Overall, I believe the NRC staff should be commended in the
way they articulated the industry's concerns with the past generic
communication process, and I think during the staff presentation, those
concerns were identified in terms of use of the compliance exception,
invoking 50.54(f) as a basis for action or response, if you will, from
licensees.
The process that was previously used to define when a
bulletin is issued versus a generic letter was never clear, and I think
in the staff proposal, they are moving forward and providing significant
clarity. Historically, we have been very successful in working with the
NRC staff to identify the problem that needs to be addressed, and once
that identification and understanding is established, it becomes very
clear in terms of what the role of the regulator or the NRC should be in
dealing with that problem. So that we are very pleased to see the
emphasis on the early interaction with industry. We, quite frankly,
think that is becoming more and more important as we look into the
future.
In terms of the process that is proposed in the draft SECY,
we fundamentally believe in the concept of simplicity. I think everyone
kind of agrees with that. And so it is not clear to us the rationale or
the NRC's thinking for this new mechanisms for generic communication
that they refer to as regulatory information letter. I think,
historically, recognizing that generic letters were used in the past, it
is not clear to us at this point what the differentiation or what the
distinction is between generic letters as the staff currently proposes
and this new generic communication mechanism, so that is one area we
hope to clarify.
Let me just offer a thought about bulletins. I think,
historically, bulletins have always dealt with specific hardware related
issues. There is a piece of equipment that the NRC knows has been used
at a number of plants in the industry, and the NRC feels immediate
action is necessary to deal with that problem in terms of the
performance of the equipment and the performance of the equipment within
the system, et cetera. And I think that process, or the ability of the
NRC to deal with those kinds of issues needs to continue.
But, again, I think, over the years where the NRC and
industry have interacted on the scope and magnitude of the problem, that
has been very effective in helping the NRC articulate the specific
requirements to be imposed in the bulletin or the specific requested
actions, and I hope that that process continues.
We are looking forward to meeting with the NRC staff
sometime in the not too distant future, hopefully, to get a better
understanding of what is being recommended.
I found the flow chart or decision chart that the NRC
identified during the presentation earlier to be of interest because I
had the same concerns that some of you, ACRS members, had relative to
the identification of the emerging concern, the specific issue -- what
is the problem that creates some concern or interest on the part of the
NRC, and what is the best way to deal with it? But, fundamentally, in
terms of identifying the best way to deal with it, there are a couple of
other questions that need to be addressed, and that is one of safety
significance, in terms of impact. There is another once with regard to
adequate protection, and whether or not the concern falls within the
scope or the existing framework of a regulatory requirement, as captured
in 10 CFR Part 50. Those are the kinds of questions and issues that
need to get thrashed out and a better understanding established to make
this new process work.
DR. KRESS: In your opinion, what should be the criteria for
this urgency gate? What should constitute something urgent enough to
issue a bulletin?
MR. MARION: Well, historically, it has been situations
where the NRC was aware of equipment being installed in a plant whose
performance was questionable. And I go back to the bulletin on
Rosemount transmitters, the bulletins on substandard circuit breakers,
and those were both excellent examples of where the industry and the NRC
worked together to understand the scope and magnitude of the problem.
And once you achieve that understanding, then it becomes clear what
NRC's statutory role and responsibility is, and in those cases, they
issued bulletins focused on safety-related applications.
In a complementary way, the industry, through NUMARC at the
time, pursued action that the NRC felt was necessary, but more
comfortable with the industry taking the lead on dealing with. And I
think when both efforts in parallel were completed, the problem was
adequately resolved and addressed by everyone concerned.
So I think the urgency is based upon specific knowledge of a
hardware problem at a plant.
DR. KRESS: That hardware should be safety-related?
MR. MARION: Fundamentally safety-related, yeah. That is --
you know, that is the way it has worked in the past, and it is an area I
think we need to discuss in detail with the NRC staff to see if it
serves us into the future, in light of this new process.
There were some comments made during the staff presentation
about DSI-13 and I would like to just elaborate on it a little bit.
There are two elements of that direction setting initiative. The first
deals with NRC participation and endorsement in codes and standards and
the second deals with NRC use of voluntary industry initiatives in lieu
of regulatory action, and there are two separate SECY letters that have
been issued on both of those. However, I hope we don't move forward in
dealing with these separately. I think they are all connected.
Obviously, the question that I have of the NRC is, in terms
of NRC endorsement of a code or standard at some time in the future,
what generic communication, or which generic communication mechanism
will be used?
Will it be a generic letter or regulatory information letter
or some other mechanism. I am not sure, but those are the kinds of
questions we need to address.
With regard to voluntary initiatives we are very
sensitive -- yes?
DR. POWERS: The answer to the question -- if I follow their
decision logic, I suppose if they saw a consensus and that it's pretty
standard and it was attractive to them, they would get together and say
you, industry, do you find this attractive? And you say oh, yeah, we're
100 percent on that -- then it would come out as a regulatory
information letter.
MR. MARION: I would concur with your interpretation but I
think we need to have detailed discussions with the NRC to make sure
that that is adequate and sufficient from their perspective.
The point I was going to make about voluntary industry
initiatives is that we recognize that there are some things that the NRC
has not choice but to do in terms of regulatory action. In our
reviewing the SECY letter on the voluntary initiative, which is
SECY-99-163, I believe, it because clear that the NRC Staff concept of
regulatory action may be different than the industry's concept of what
regulatory action is, so given that that terminology is used throughout
all three of these documents and these three areas, that is one of the
key areas I think we need to have some good extensive dialogue with the
NRC Staff on.
I can tell you now if, depending on which interpretation you
use, your understanding and reaction to the SECY letters can be quite
different, and I think we need to clarify that given the importance of
these documents. Also --
DR. POWERS: I think what you are saying, to interrupt you,
is that the industry is a little more sensitive, and things that NRC
thinks "well, we are just trying to get information and what not and
learn a little more about that issue" has the impact on the licensee of
NRC is taking an action here, and I am being forced to do things that I
would not ordinarily do, and so it must be an NRC action, whereas these
guys over here will think, well, we are just trying to get a little
information and think about this thing. Your gain is turned up higher
than theirs on this.
MR. MARION: Well, if I might just take it a little bit
further, if you read that SECY on voluntary industry initiatives and
think about regulatory decision-making process, a lot of what the NRC
has articulated I submit makes sense, but if you look at it from the
standpoint of an actionable thing in terms of the output of NRC's
regulatory decision-making process, you get a different read on a
document and so that is why I think that is a very important point that
needs to be clarified.
One other area we are very careful about is -- and there is
a flavor of this in all three letters -- and there is a suggestion that
the voluntary industry action, whether it is through an industry-wide
effort via the Nuclear Energy Institute or through a particular owners'
group or a combination of owners groups or EPRI, there is language that
suggests that this is an alternative option for the NRC Staff to pursue
because they can't justify it through their internal processes.
That is something that has to be very carefully thought
about and discussed because it would not serve either the industry or
the NRC well if externalized to the public this perception exists,
okay? -- and I just plant that for your thought and future
consideration.
In closing, let me just say that overall we are really
positive of the improvements that have been articulated. There are some
things that we need further clarification on and we are looking forward
to working with the Staff in all of these areas in the hope that generic
communications in the future once the process is agreed to are
understandable to the NRC Staff and understandable to the recipients who
are the utility licensees as well as to the public, and I think that is
our fundamental objective in all of this, and so I would like to ask if
there are any questions at this point.
DR. POWERS: I guess I am a little surprised that you -- we
haven't been more concerned about this difference between the regulatory
information letter and the information notice.
MR. MARION: Oh, I can get into that a little bit more, if
you like.
[Laughter.]
DR. POWERS: I would like to hear what you have to say.
MR. MARION: My concern is terminology is terminology but I
think today given the legal ramifications of everything you say and do,
you have to be extremely careful about the words that you use.
My concern is not so much in terms of the regulatory
information letter and the information notice, because I think
information notices have a certain standing and a history that is well
established and understood.
The area of clarification that I have is between a
regulatory information letter and a generic letter. That is where I
think we need to thrash out some specific details, and I little bit of a
clarification on bulletins. I think if bulletins were focused on
hardware related problems it would clearly take that mechanism of
generic communication and separate it from the other three, and I think
bulletins are very important and when NRC issues one they are taken
very, very seriously by the industry.
In terms of the information request -- you got me started
now, Dr. Powers, since we are still ahead of schedule I would like to
take a couple more minutes, if that is okay.
In the discussion in the draft SECY the NRC indicates that
the generic letters will be used to request action or request
information so the red flag that raises is request action, and the
thinking is that if you use bulletins to request action that are
immediate, then why not use a bulletin? If you want to request action
that is of a different priority then you need to identify and
characterize what kind of action that is, and it gets back to this
earlier comment I made about regulatory action on the part of the NRC
versus the recipients.
DR. MILLER: But you said you thought bulletins should be
primarily on hardware issues.
MR. MARION: Yes.
DR. MILLER: There could be actions of course that would not
be hardware issues. That would apply through the avenue of the generic
letter.
MR. MARION: Well, that is something that we would like to
discuss with the Staff. I am going through my recollection of
bulletins. The majority of them, nearly all -- okay, there might be one
or two -- they are really focused on hardware issues.
DR. MILLER: I think the other question would be do they
really need generic letters and regulatory information, both categories.
MR. MARION: That is one of the questions I think we need
to address. That is a good point.
DR. POWERS: I guess I am really concerned if we put a
constraint on bulletins to be strictly hardware, just because I kind of
look at the world and I say we have got an awful lot of operational
experience. A lot of the hardware problems are disappearing. But we
may have other problems that operational experience hasn't resolved that
may appear and I wouldn't want to foreclose, it seems to me, the
possibility of using a bulletin if it was called for on a non-hardware
problem.
MR. MARION: That is a fair point but that is something we'd
like to discuss with the Staff and thrash out the details. Examples of
that I think would be very helpful.
One other aspect of the regulatory information letter, and
recognize that the SECY paper is a work in progress as I think Tad Marsh
indicated earlier, is one of the first reasons they are going to be used
is to announce Staff technical or policy positions not previously
communicated to the industry.
That again raises the flag and it gets back to this
compliance exception discussion. The thinking is, well, if it is a
regulatory position then it should be articulated in the regulation --
fundamental, okay? -- or it should be articulated in the licensing
basis commitment by a licensee -- very fundamental.
If there is something else that needs to be addressed via
this communication mechanism then we need to find out what that is and
get it integrated into this process so it is very clear when you use any
one of these four mechanisms and that is another area of question I have
on this regulatory information letter.
That's pretty much it because I can go on with specific
details but I would rather discuss them with the NRC Staff and work it
out.
DR. FONTANA: Additional questions? Any from the floor?
[No response.]
DR. FONTANA: Well, thank you very much.
MR. MARION: Thank you.
DR. FONTANA: Enjoyed the discussion. Turn the meeting back
to the Chairman.
DR. POWERS: Thank you. I am going to declare a recess I
believe until 3 o'clock.
[Recess.]
DR. POWERS: I know that the Members have spent the last 45
minutes in detailed discussions on highly technical issues, and that
they will be prepared to delve into the next topic with an enthusiasm
that's unparalleled. And I am also informed by John that he's making
arrangements that all future breaks will be accompanied with the same
sorts of refreshments, and his failure to do so should be brought to his
attention immediately.
DR. SHACK: I'd say there's a year's supply of stuff still
sitting there.
[Laughter.]
DR. SEALE: What do you think you're going to get Saturday?
DR. POWERS: The next topic on our agenda is a potpourri of
everything that you've ever wanted to know about the pressure boundary
in a reactor, and it's been the subject of a subcommittee that hopefully
has distilled out of this the salient points. So I won't anticipate
what all we'll hear about, but I'll turn it over to Professor Seale.
DR. SEALE: I think Bill's going to start it.
DR. SHACK: I'm going to start and then I'm going to recuse
myself.
DR. POWERS: Dr. Shack will begin the discussions then.
DR. SHACK: Okay. We had a Materials and Metallurgy
Subcommittee meeting on March 24 and 25 where we did hear about a
variety of things. Among them was the resolution of Generic Letter
92-01. This generic letter arose out of the Yankee Rowe situation where
the -- we wanted to avoid some surprises and have the licensees review
the bases for their vessel integrity and their embrittlement programs.
That initial generic letter did produce a surprise of its
own and in Palisades, and another generic letter, 92-01, Rev. 1, went
out where the licensees were asked to look at the impact of any new data
on their embrittlement analyses and to -- the NRC used the responses
from that generic letter to come up with a complete and integrated data
base on reactor vessel integrity, the so-called reactor vessel integrity
data base.
One other item we heard about related to pressure vessel
integrity was a change to the ASME Appendix G, which was changed to use
the K-1-c initiation toughness rather than the arrest toughness in doing
your pressure-temperature curve evaluations.
Essentially it's a rather sensible change that since you are
worried about initiating a crack, the original work to use the arrest
had been for fear that there were brittle regions that would pop in and
you would have to arrest. Since nobody's ever found these brittle
regions in an operating reactor, they decided to change the initiation
toughness curve.
That will give the operator some flexibility in going
through their startups. The licensees will have to apply for an
exemption to use this as a proposed alternative, since we already have
an Appendix G -- another Appendix G in 10 CFR 50 that prescribes the use
of the K-1-a.
We heard about a new initiative from the PWR people, a
materials reliability program, dealing with a number of issues that
arose out of the work that they had done on Alloy 600 cracking on
pressure vessel penetrations. They're picking a number of issues to
work on related to pressure vessel integrity, pressurized thermal shock
and PT limits. They'll also be doing some work on reactor pressure
vessel internals in PWRs, and they've also decided to look at some
problems with thermal fatigue in PWRs.
We heard a resolution of Generic Letter 97-01, which was
involved with the Alloy 600 penetrations in reactor pressure vessels.
You may recall that in France they've had a substantial number of these
penetrations that exhibited cracking. In the U.S. the owners -- or the
PWR owners' groups developed susceptibility models and a number of the
high-susceptibility plants have now done inspections. Basically a half
dozen of these plants have had comprehensive exams, and only one vessel
had penetration, at D.C. Cook did they find any flaws, and these were
three small flaws. And the staff has accepted the industry integrated
program for the management of this problem, and it's intended by the
industry that this will be a management for the operating reactors and
for license renewal.
We also heard from the BWR vessel Internals program people,
BWR VIP, which was actually the model for the PWR owners' group. The
BWR group started out in 1994 to address the issues arising from the
core shroud cracks. And they have decided to sort of proactively
address a number of issues associated with BWR vessels and internals.
We heard a rather detailed presentation on BWRVIP-05 dealing with the
inspection of the circumferential welds in pressure vessels where they
effectively managed to convince the NRC to grant them relief from the
inspection of those circumferential welds based essentially on a
probabilistic fracture mechanics argument.
DR. POWERS: That was a particular case where the staff went
through and did their own independent analyses, and the convincing was
that they came to the same conclusions.
DR. SHACK: They've also developed a number of inspection
and assessment guidelines for most of the BWR internals. Again the only
one of those internals that's really covered by the ASME code is the
shroud. They have now developed inspection and assessment guidelines
for essentially all the components in the BWR jet pumps and such,
guidelines for hydrogen water chemistry.
Again, the staff has not accepted all these BWR VIP
documents, and many of them are still under review, and they're in
various states, but again, it seems to be a very successful program.
The BWR VIP people have now decided to move on to dealing with problems
in the recirculation piping. I guess they're not going to change the
name, but they'll just move on to essentially update some of the
inspection efforts associated with NUREG-0313.
We also heard an update on the work on the piping seismic
design criteria. If you recall, the 1994 addenda to the ASME Code,
section 3, raised allowable seismic stresses for piping. The NRC
decided not to accept that. They thought the stresses were too high,
that there was a misinterpretation of the results. The code has set up
a special working group, and I guess the answer is they're still working
on the problem. It hasn't really been resolved yet. They have some
other approaches to defining margins that are being considered. So this
is still a work in progress.
One particular element of interest is the discussion of
proposed modification of 10 CFR 50.55(a). Currently plants are required
to update their in-service inspection programs every 10 years to the
latest code case that's incorporated by reference in the code. One of
the proposed modifications is to change 50.55(a) to eliminate this
requirement to go through the update, that it would be made voluntary
rather than mandatory. And we may want to write a letter discussing
that.
The other issues that were presented were dealing with steam
generator tube integrity, a slightly different approach to the handling
the regulatory issues in which the staff is really considering endorsing
a guideline being developed by the industry. There's a number of
unresolved technical and regulatory issues associated with that yet, and
some risk issues associated with the steam generator tube integrity.
Again, this is a question of whether we're working on a design --
current design basis or considering risk when we're considering changes
to the steam generator tube integrity.
DR. SHACK: We'll be hearing presentations on that today.
We'll also be hearing some presentations on the proposed approach for
modifying the PTS rule and some of the other ongoing research activities
associated with the pressure vessel research integrity program.
I'm not sure who is going to start off.
MR. DUDLEY: That will be Tom Scarbrough.
DR. SEALE: Tom Scarbrough I think is the --
MR. DUDLEY: With 50.55(a).
DR. APOSTOLAKIS: So do you recuse yourself now?
DR. SHACK: No, not yet.
DR. APOSTOLAKIS: Not yet. Still have the power.
MR. SCARBROUGH: Okay. I'll wait until you get your copies
there.
Okay. Good afternoon. My name is Tom Scarbrough, I'm in
the mechanical engineering branch of NRR, and we're going to give you a
very brief overview of a proposal to supplement an amendment -- a
proposed amendment to 10 CFR 50.55(a) that was issued in December of
1997, and it deals with the ten-year update requirement.
Okay. Just a little introduction. Let me sort of -- this
is kind of an overview slide, and then some slides that have some more
detail, which I won't go into much discussion. But the regulations
require plant owners to construct, inspect and test specific components
in accordance with ASME boiler and pressure vessel code. The current
requirements in 50.55(a) require licensees to update their in-service
inspection and in-service testing programs every 120 months, every ten
years.
In December of 1997, the NRC published an amendment to
50.55(a) to update the regulations to incorporate by reference more
recent additions and addenda of the boiler and pressure vessel code and
also a new code which deals more with IST service testing, the code for
operation and maintenance of nuclear power plants, and I'll indicate
which versions they were going to endorse in just a minute.
Based on public comments we've received and the maturity of
the code, the staff is considering eliminating the requirement for
licensees to update their ISI and IST programs to every ten years. So
to start that off, we prepared a supplement to that proposed rule which
we intend to send out for public comment which would propose the
elimination of that ten-year update requirement, and we discussed this
in Commission paper SECY 99-017. The Commission sent us a staff
requirements memo accepting that proposal to go out for public comment,
but also indicating that we should address advantages and disadvantages,
benefits and impacts of that proposal before the proposed amendment goes
final.
Okay. The current requirements in 50.55(a) currently
require that class 1, 2 and 3 components be constructed to the 1989
edition of section 3, so it's a few years old. In terms of inspection,
also the 1989 edition of section 3. Metal containment and concrete
containment components are required to be inspected to the 1992 edition
of section 11, and then class 1, 2, and 3 pumps and valves are to be
tested in accordance with the 1989, and then there is a slight reference
to the ASME O&M Code, but it's very preliminary in that the code was
more of a standard back at that point in time.
But that's what the current requirements are.
Then in 1997, December, there was a proposal to revise
50.55(a) to incorporate by reference the 1995 edition with the 1996
addenda of section 11 for ISI requirements for class 1, 2, and 3. It
also required PWRs, pressurized water reactors, to perform volumetric
examinations of class 1 portion welds in high pressure safety injection
systems. It also expedited the implementation of Appendix 8 of the 1996
addenda dealing with the qualification of personnel performing
ultrasonic examinations.
It incorporated by reference the 1995 edition with the 1996
addenda of the ASME O&M code for IST requirements for pumps and valves
and also required licensees to supplement their IST stroke time testing
for motor-operated valves, but it also -- and it also permitted the
implementation of certain code cases and portions of ASME code.
So that's what was proposed back in '97.
Now, the supplement will go out and just be an additional
add-on to that December '97. We're not going to do anything more than
just deal with the ten-year update issue in the supplement, and we hope
to have it out for public comment in the next -- within the next month.
It's with the EDO right now for his signature.
What the supplement would do, it would eliminate or proposed
elimination of the requirement for licensees to update their ISI and IST
programs. It would establish a baseline edition for the ASME code of
ISI and IST, and that's something that we're going to specifically ask
for public comment regarding as to what is the proper baseline. But
right now, in the current version, we are proposing a 1989 edition for
ISI and IST requirements for class 1, 2 and 3 components, to 1992
edition for subsections IWE and IWL of section 11 having to do with
containments, and then the 1995 edition with the '96 addenda for the
Appendix 8 requirements regarding the qualification of personnel.
It will also allow licensees to voluntarily implement later
editions of the code. There would be conditions on that.
Now, for future licensees, they would be -- continue to be
required to incorporate the latest version of the code endorsed by
reference in the regulations prior to their receiving their operating
license. But once they implemented that version of the code, they would
not be required to update periodically like licensees do now.
DR. FONTANA: Future licenses also refer to license renewal
applications.
MR. SCARBROUGH: They would continue to use what they're
doing now.
DR. FONTANA: What they're already doing.
MR. SCARBROUGH: Right.
Okay. So as you can imagine, this has a number of issues
associated with it, and in our public comment notice, we outlined all of
these and highlight all of these issues that we would like to have
public comment to come into us so that we an address these.
For example, the potential effect on safety, will this have
any reductions in the effectiveness of the ASME code? What is the
proper baseline edition to select -- '89? '95? '98? The regulatory
benefits and burdens to licensees, also industry suppliers, nuclear
insurers, the states and standards organizations all have a role here
regarding the 50.55(a) ASME code, and we want to find out as much as we
can regarding the benefits and burdens associated with them.
The burden on licensees to update their INIC programs.
We've received differing information in terms of how significant that
burden is and we want to be able to characterize it properly as we go
forward.
We want to know more about the potential effect on the
licensees' submittals in terms of the number and details if we establish
a baseline and licensees want to use later versions.
We also want to find out if there's going to be a
significant change in the range of code editions that licensees might be
applying which might have an effect on inspection effectiveness and
efficiency.
We also want to find out about any potential effect on
processing of licensing actions. The regulatory guides that endorse the
code, how will that be processed, how will that be taken care of, and
any effect that this might have on the risk-informed ISI and IST
initiatives, which we have a lot of effort involved with.
We also want to find out more about the potential effect on
state and other organizations that rely on the code in their
interactions. There's a lot of cross-referencing there in the states
and nuclear insurers we want find out more about. Also, we want to be
able to determine what's the proper application of portions of future
ASME codes. It's referred to as cherry-picking in terms of future
codes, and how will that be dealt with in terms of licensees wanting to
use only portions of later codes.
So those are the major issues that we feel we need to
discuss. The Commission in their SRM back to us on this issue indicated
that they also want to hear more about the advantages and disadvantages
before this goes final. So we intend to deal with that before this is
finalized.
Future plans. We have scheduled a public workshop for May
27th here in the 2 White Flint North auditorium. We've invited ASME and
NEI. We're also going to make sure that it's on the Web, NRC Website,
and also get as much information as we can out there to potential
stakeholders so that they can feel that they should come and provide
input as much as possible.
Then once we go through the public workshop and the document
is issued for public comment, which we hope to have happen sometime the
first of May, then we're going to have a 60-day public comment period.
That's the current plan. After that, we'll take the comments we receive
from the public workshop and the interactions there, the written
comments we receive from all the stakeholders and the public and begin
the preparation of the final draft rule.
So we hope in the fall of '99 to have that ready for NRC
agency review, and then, in late 1999, to be able to present a draft
final rule to the ACRS and CRGR for their and your review, and then in
early 2000, to submit a final rule to the Commission for their approval.
So that's our current plan. I'll be happy to answer any
questions about it.
DR. POWERS: A lot of the topics that you're dealing with
reflect on the ASME code. In fact, I think you had one of them there
that's entitled something -- impact on the effectiveness of the ASME
code.
MR. SCARBROUGH: Right.
DR. POWERS: My understanding is the ASME has a standing
committee that annually updates relevant portions of the code.
MR. SCARBROUGH: It's an ongoing basis, yes.
DR. POWERS: I wondered how this schedule interfaced with
their schedule, and was this committee going to be able to respond to
your call for public comments?
MR. SCARBROUGH: Yes. We've talked to Jerry Eisenberg, who
is our contact with ASME, and we rescheduled the public workshop to fit
their schedule better, and also extended the public comment period from
an initial 30 days to 60 days to be able to -- better be able to serve
them, to allow them to give us as much comment as they possibly can.
So yes, we've been in discussion with them on that, and also
with NEI as well.
DR. FONTANA: Should we be concerned that they don't have a
requirement to update their ISA and IST every 10 years?
MR. SCARBROUGH: I think one of the ongoing philosophies
with this process of the 10-year update was over time the testing
requirements, the techniques, the new equipment was an improvement in
safety over time. If you go back and look at the very early
descriptions of the 50.55(a) and the statement of considerations, that
was one of the bases for the 10-year update requirement. If that is
eliminated that will have to be taken into consideration or the plants
as they are now with the equipment they have now, the techniques they
have now, is that sufficient for long-term? Now if we did -- as the
ASME code is continued to be revised -- if we did find something that
was safety significant that met a backfit test, of course we would go
through that process and apply that, so that wouldn't eliminate the
51.09 backfit process. That would still be in place.
Then also licensees would have the option to update where
they saw a benefit to that and I know there's going to be an effort to
try to have licensees take future editions of the code in total rather
than cherry-picking bits and pieces so that you get the whole concept of
the code rather than just bits and pieces.
I know that there's going to be an effort to do that as
well, so I think there's going to be an effort there to continue the
improvement of the techniques over time, so I think there is some safety
net there and there's some goals to try to make sure that we continue to
improve the techniques and such but I think it is a consideration
without a mandated 10-year update, as we have done in the past, will
that have any adverse effect on safety and that is something we will
have to consider.
MR. BARTON: I noticed at the March 25th meeting that the
dates, your dates here have slipped since the dates several weeks ago.
Are you confident in these dates now?
MR. SCARBROUGH: As much as I was on the other ones.
[Laughter.]
MR. BARTON: That's not very comforting.
MR. SCARBROUGH: Yes, I know. What we did was there were a
couple of things that caused us to adjust it. Some of the dates we gave
the subcommittee a few weeks ago were the actual dates in the SECY
paper, 99-17, and it took -- the Commission is very interested in this
issue and took a significant look at it and took longer to review than
we had anticipated, so we go off to a late start there.
In addition, we decided to extend the public comment period
from 30 days to 60 days, so we added another month on, so what we
basically did was we slid the schedule about two months from the
original December, late December '99 to like February 2000.
MR. BARTON: Okay. Understand what you did.
MR. SCARBROUGH: Okay.
DR. POWERS: I guess I am intrigued by a lot of this and I
am going to offer some comments that you don't really have to respond to
because they are really more directed to the rest of the members, but if
you have a response I would be interested in what you have to say.
In our recent quadripartite meeting we saw numerous of our
partners discussing their approaches to episodic updates of plant
safety, and it was not uncommon for them to have 5 and 10 year updates
in which they were requiring plants to use the latest of technology. I
think that was true with all three of our partners -- Germany, France
and Japan.
They did that because they don't have a prescribed license
period and in fact in principle each of their licensees at all times is
supposed to be up to date, but they have these major reviews at either 5
or 10 years. We seem to be moving even further away from that concept
that the rest of the Western reactor world has.
I am wondering if it isn't our obligation to make sure the
Commission is aware that the rest of the world is taking a different
view on this process than we are.
DR. APOSTOLAKIS: What is the rest of the world updating?
ISI requirements too? Are they using ASME codes and so on or --
DR. POWERS: It is not uncommon for them to use the ASME
code, particularly in Japan. I am not absolutely positive about France.
It wouldn't surprise me in Germany.
I mean they clearly have a different regulatory approach but
nevertheless I am wondering if it isn't useful for the Commission to be
aware that that we are taking a tack that is not the same -- better or
worse, I am not sure we are in a position to comment on -- but it is
certainly different.
DR. APOSTOLAKIS: It seems to me we would have to tell them
more than just that.
DR. POWERS: Why?
DR. APOSTOLAKIS: Well, just to say that somebody is
updating his or her requirements more frequently without explaining what
kinds of requirements you are talking about, and why they have to do it
and all that would not be very useful to them, would it? Of course the
system may be different. Maybe their requirements are different. I
don't know.
If you only say that they are doing it more frequently there
is an assumption there that we are all operating using the same codes
and the same --
DR. POWERS: I think it is not the frequency that is of
interest here. It is that when they come to these 10 year reviews they
say, okay, you should be using the latest technology, which means you
use the latest version of the codes, you use the latest research results
to re-evaluate your plant.
DR. SHACK: We saw something of that in the presentation we
had on the Swiss analysis.
DR. POWERS: That's right.
DR. SHACK: They really wanted their plants to be at the
state-of-the-art.
DR. POWERS: At the state-of-the-art, that's right. I think
the Swiss do the same thing. They are not a member of the
quadripartite, but I am pretty sure most of Europe does this. It is
their approach.
We have a little different regulatory philosophy and that is
that what existed at the time you got your license you can preserve.
You have the option to update it but you can preserve that through all
time, so somewhere in this planet there is every version of the ASME
code that has ever come out because it applies to some reactor. Is that
correct?
MR. SCARBROUGH: Well, right now they are required to
update and everyone up to '89 right now. I think that is one reason why
I think '89 was sort of picked, because the starting point was there's
only a handful of plants that haven't updated to '89, so everybody from
'89 upward update only under certain conditions.
DR. POWERS: It's intriguing. That is the only thing I can
say about the thing. I am not willing to offer an opinion, better or
worse, here because I think you have to have some idea of how the
updates are going. Are they going in a more conservative or more
liberal direction, and I think the answer is both.
MR. SCARBROUGH: There's a little bit of both in all of
them.
DR. POWERS: I think I can point to cases in which the ASME
codes become more conservative over time and I can point to cases where
it's become more liberal in time.
DR. APOSTOLAKIS: And I have a comment also that may not
require a response. I remember our Chairman saying in the past several
times, asking a rhetorical question, whether a regulatory agency should
be using state-of-the-art methods or methods that are good enough.
[Laughter.]
DR. POWERS: He did indeed ask that question many times, and
he was not shy about expressing his opinion on that either.
DR. MILLER: As unusual as that may be.
DR. SHACK: I have a little problem with you make your
argument based on the maturity of the inspection technology and then you
look at the past 10 years and you say, well, you know, I have got baffle
bolts cracking, I've got BWR internals cracking, erosion/corrosion has
suddenly come to the fore. I have decided that rather than prescribing
how the guy ought to do the inspections I ought to have performance
demonstrations so that in fact he demonstrates that he can actually find
something when he does the inspections.
A technology that depends strongly on instrumentation and
computers in 10 years is four generations and to say that it has
matured, you know, in 1999 --
DR. POWERS: A bit on the arrogant side.
DR. SHACK: -- is almost mind-boggling. I really find it
very difficult to -- inservice inspection is a difficult thing. Does it
make the plant safer? It's really a defense-in-depth argument, that the
plant is operating safety. It is there to detect changes in the
situation and I don't find 10 years at all an unreasonable interval to
go back and make sure that I am using effective techniques that detect
degradation.
MR. SCARBROUGH: I think there is quite a difference of
opinion on this and there's lots of issues that we have mentioned that
need to be addressed. We want to gather as much information as we can
to be able to make the most informed decisions before we go forward, so
all this is just in line of what we have heard.
We have heard go slow, be careful, you know, make sure you
look at all the pros and cons before you go too far down this path.
DR. UHRIG: What is the driving force behind this? Is it
economics? Is it relief of burden?
MR. SCARBROUGH: I think that is -- at some point you say we
have been doing the 10 year updates for many, many years through these
plant lives, and has it got to the point where the code has matured
enough that it is an unnecessary burden on licensees to do the 10 year
updates? I think that is a question that is reasonable to ask at this
point in the lives of the plants.
DR. SHACK: Yes, but then you look at the last 10 years, and
what is the answer you get?
MR. SCARBROUGH: There's a date on the other side, too.
DR. POWERS: It's been a busy 10 years.
DR. SEALE: I think your comment about the fact that it is
four lifetimes -- 10 years is four lifetimes on some of the test
equipment and so on is appropriate too and that is why when you say you
give a little and take a little, it's because it's the whole package
that gives you what you want and it's the giving and taking that gives
you the new balance, and cherry-picking can get very, very risk in those
cases, because you may throw away the important part of a process if you
pick and choose among the requirements of the different code cases.
MR. SCARBROUGH: We have that same concern.
DR. SHACK: Do we have any comments from NEI? Kurt, care to
say anything?
MR. COZENS: No, not at this time.
DR. SHACK: Any additional comments from the Committee?
DR. APOSTOLAKIS: Are we expected to write a letter on this?
DR. SHACK: I think we can discuss that since it just goes
out for public comment. We could either --
DR. APOSTOLAKIS: Is the staff requesting a letter?
MR. SCARBROUGH: No, we are not requesting a letter. We
appreciate your feedback you are giving us because it reaffirms our need
to look at these issues very carefully.
DR. SEALE: If the points that Dr. Powers has raised,
though, are generally shared and so forth, it might be more appropriate
to bring them to the attention of the Commissioners now.
DR. APOSTOLAKIS: Which points now? Today or two years ago?
DR. POWERS: In this environment, I am not sure that either
one of my points are off the board here.
DR. SEALE: That's right.
DR. POWERS: Part of our obligation to the Commission is to
acquaint them with the dilemmas, the uncertainties, and the
considerations and, given the status of the staff's investigation and
the apparent genuine interest in understanding exactly those things,
presenting two sides of the coin is not a bad position to take right
now.
DR. SEALE: It is better to bring it up now than to wait
until after the comment period to bring them up, if we really feel that
those are important issues. We are messing up our schedule.
DR. BONACA: I just have one question. You know, with this
-- from some perspective, one might see several of these as relaxations.
What happens for life extension?
MR. SCARBROUGH: Life extension would -- the plants that are
currently operating and licensed, once the baseline is selected, that is
their baseline for the remaining life of the plant. You know, they
would only be required to update to something if there was a 51.09
backfit analysis, where they might choose to encompass an entire new
version of a code and go up. But they would be treated just like any
other currently operating plant.
DR. SHACK: I think that completes it. I am going to turn
this over to Dr. Seale now since we are on to steam generators and I
have a conflict of interest there.
DR. SEALE: Thank you very much.
DR. POWERS: You didn't say a lack of interest did you?
DR. SHACK: No.
DR. SEALE: Well, just to show how, when you are having fun,
times passes in a hurry, we last talked about steam generator tube
integrity with the staff back in September of '97, and wrote a letter in
which we recommended that a proposed generic letter be issued for public
comment and draft guide 1074. At the time we believed these
specifications contained in the proposed letter and in the draft guide
would provide improvements by requiring licensees to perform condition
monitoring, operational assessment and non-destructive examination and
qualification.
Since then, the staff has postponed the issue of the draft
-- of the proposed generic letter, withdrawn the associated advanced
notice of proposed rulemaking and met with the NEI concerning technical
and regulatory issues related to steam generator integrity.
The staff and the industry representatives have made
progress in resolving the technical issues and reached a conceptual
agreement on the regulatory issues. Neither the staff or the industry
have yet identified a particular regulatory approach to implement this
agreement, however.
We might be interested or wish to comment on the following
topics: proposed changes in the technical specifications for plants,
reliance on ASME code requirements, allowable or worse -- I should say
worst differential pressures, secondary to primary, accident induced
leakage, the definition of tube burst and tube rupture conditions, what
those are, and the risk issues concerning each of these.
Mr. Murphy is going to fill us in on this particular topic,
and we are expected to write a letter.
MR. MURPHY: Can you hear me?
DR. SEALE: Yes, sir.
MR. MURPHY: Well, it was my intention today to give you a
brief update, in the ten minutes that I have, on the status of NRC and
industry initiatives on steam generator tube integrity issues. So, it
wasn't my intention to get down to any real detail on some of the
details of the technical issues, other than to give you a sense for how
we are proceeding and the chance for success.
When we last met in September and October of '98 to discuss
the draft GL package, we explained that the purpose of the draft GL, or
the proposed GL, was to inform utilities that actions beyond minimum
technical specification requirements were necessary to ensure tube
integrity, and to request that they submit changes to the tech specs as
needed to ensure that tube integrity is maintained.
The package included a draft regulatory guide which provided
an acceptable methodology for accomplishing the goals of the GL and the
methodology was intended to be performance-based. It identified a set
of performance criteria or performance goals in the areas of tube
structural integrity and tube leakage integrity, and provided for
periodic tube integrity assessments on the condition of the tubing
relative to the performance criteria.
Finally, the package included a proposed resolution of a
differing professional opinion which was filed by an NRC staff member.
The fundamental concern on his part was that operation with degraded
steam generators may lead to a high frequency of core melt scenarios and
accompanying containment bypass. There were a number of sub-issues or
sub-topics relating to that DPO, but that was the bottom line concern,
and, furthermore, that, in his mind, the proposed GL and accompanying
regulatory guide would not really resolve the issue. And that was our
proposed resolution of the DPO and a discussion from the individual
concerned were both made to the ACRS in October '97.
In December of '97 industry informed NRC of an initiative
that they had taken to adopt a formal industry position which stipulates
that each licensee will evaluate its steam generator program and where
necessary revise and strengthen the program to meet the guidance
provided in NEI 97-06 entitled "Steam Generator Program Guidelines," and
that implementation of this program should be undertaken no later than
the first refueling outage after January 1, 1999.
And, incidentally, the industry has, you know, that
commitment remains in force, and the industry is -- individual utilities
are in fact implementing the guidelines.
NEI 97-06 is programmatically similar to DG-1074 in terms of
general program elements and strategy, that is, it relies on a set of
performance criteria in the structural and leakage arena and periodic
tube integrity assessments to ensure that the criteria are being met.
However, significant differences exist in the details, including
technical, regulatory, and risk issues.
After considerable deliberation then the staff proposed to
the Commission in SECY-98-248 that the staff would delay issuance of the
draft GL while it works with the industry to resolve issues relating to
the NEI guidelines. We noted that technical differences still remain
between the staff and the industry, not just in the technical arena but
including the appropriate regulatory framework for implementing the
industry guidelines, and that it was our objective to be in a position
to endorse an industry initiative for ensuring steam generator tube
integrity in lieu of issuing a GL.
However, we also proposed and the Commission accepted the
issuance of the draft DG-1074 and the proposed DPO resolution for public
comment, and this was done in January of this year. The comments on the
reg guide and the DPO resolution are due by the end of June of this
year.
DR. SHACK: I know you wanted to avoid details here, but I
just wanted to clarify something I'm just trying to remember from the
subcommittee meeting.
There was the intent when the licensee wanted to propose a
repair procedure criterion that you would review the first application
of that.
MR. MURPHY: Yes.
DR. SHACK: Would that then become part of his tech specs,
or he would do that under 50.59 for subsequent applications and for
other licensees?
MR. MURPHY: Mr. Mizuno, in the back of the room, may care
also to chirp in if I misspeak here, but our intention, our goal, is to
have a tech spec written in such a way that a licensee who's proposing
to make first-time use of a new ARC would be obliged to come in for NRC
review and approval.
Staff's SE in response would, assuming that we approve the
proposal, would identify the parameters defining the limits of
applicability of the staff's approval to that specific methodology,
because the proposal will be made in the context of a plant-specific
situation. But the idea is the staff will say yes, we approve the
licensee's proposal, and we find a similar proposal from other licensees
to be acceptable provided, you know, they fall within a certain box, and
we'll define that box very carefully in the SE.
Other licensees -- once the staff has issued such an SE,
other licensees, if they find that they fall -- under a 50.59 evaluation
fall within the box, could implement the new ARC without a change to
tech specs or NRC review and approval.
So that is the goal we're trying to get to. I'm getting a
little ahead of myself here, but in addition to trying to dovetail our
efforts with the industry initiative as best we can to have a mutually
agreeable approach, for it to be a win-win situation, we want a product
that is going to improve the ability of the existing regulatory
framework, primarily the tech specs, to ensure that tube integrity will
in fact be maintained, but at the same time gives licensees more freedom
of action to respond to their specific circumstances without having to
come in to NRC for review and approval.
There are an awful lot of tech spec amendment requests that
come in every year -- I'll say dozens -- that propose a repair method or
plugging limit that is similar to what we've already approved for the
units, and very frequently there are no new unique issues pertaining to
these follow-on submittals beyond what we've already considered in our
initial approval. So this will I think certainly reduce the burden on
utilities and be helpful to them and the same time I think give us a
regulatory hook that we think is more effective.
We've had extensive interactions with NEI and their members
over the past six months on this particular topic, and I think it's fair
to say that we're making very good progress. There remain a small
number of high-priority technical issues that we still need to come to
resolution on before we are in a position to endorse the industry
initiative and proceed. However, the need to come to agreement on these
issues exists irrespective of whether or not the industry is going to
proceed with its initiative and irrespective of whether we're going to
have a new regulatory framework.
In fact, utilities today are already implementing the major
program elements of DG-1074 and the industry initiative. And they are
confronting the issues, what the appropriate performance criteria are to
perform the tube integrity assessments, and there is considerable
discussion going on between NRC and individual utilities as to the
appropriate performance criteria. So these are issues that we have to
face up with irrespective of this generic effort, and, you know, once we
have resolution on these technical issues, I think that this new
regulatory framework and industry initiative will leave us with a
framework that I think is far superior for them and for us than we have
today.
DR. UHRIG: Will this go out for public comment after you
resolve the issues?
MR. MURPHY: Yes. The specific scenario over the next six
months is not set yet, but it generally works something like this. The
industry -- well, in the next two or three months, before July of this
year, we'll hope to resolve the outstanding technical and regulatory
issues. Industry would then submit a generic change package which would
include in our mind, NRC staff's mind, proposed generic technical
specifications that are consistent with the resolved industry
initiative. And we would prepare an SE that, you know, evaluates the
proposed generic tech specs.
As a generic action of course this is something that we'd
have to put through CRGR and meet with you on and ultimately go to the
Commission on, and we anticipate this will take at least, you know, six
months to get through. But that's the general game plan at this point.
DR. UHRIG: There would be individual tech spec changes by
each plant that implemented this?
MR. MURPHY: Yes. For the industry to have the flexibility
they would like to have, basically they would have to eliminate existing
tech specs that pertain to surveillance of tubing, and for us to have
any sort of effective regulatory hook or enforcement ability, you know,
we need a tech spec -- an appropriate tech spec. And what we -- the
nature of such a tech spec we think would be a statement of the
performance criteria, a statement that one needs to periodically assess
the condition of his tubing relative to those performance criteria, that
one needs to have plugging criteria that have been reviewed and approved
by NRC staff.
Those are the essential elements of a tech spec. They would
be quite short and concise. Existing tech specs pertaining to steam
generators are about ten pages long, and, you know, these kinds of tech
specs will be two pages long or less. And, you know, the details of how
they meet the performance criteria will be defined not just in the
industry top-tier document but in supporting guidelines that are
referenced in the industry top-tier document.
These are referenced in the FSAR and other licensee
controlled documents. However, as part of this generic package, I mean
the generic -- as part of our review of the generic change submittal and
the tech specs that would be accompanying that change submittal, we
would expect to be in a position to be able to endorse the industry top
tier program. So we would want to be able to endorse the generic tech
specs and the industry top tier program.
DR. UHRIG: What about the technology of the inspection
systems, could this continue to be basically current technology or would
this be upgraded, or is this even addressed in the tech specs?
MR. MURPHY: Well, it is our belief that this approach will
be consistent with not taking away and perhaps enhancing the incentive
for people to use the best technology out there. When one is taking a
performance-based approach, and trying to demonstrate that the tubes
maintain certain specific factors of safety, the less uncertainty you
have in the problem, that is beneficial to you in terms of the numbers
of tubes you can leave in service, perhaps how long you can operate
between inspections. And the key to reducing -- one of the keys to
reducing uncertainty is, you know, more precise NDE measurements.
So none of the -- the tech specs would not say anything
specifically about the nature of the NDE that you do.
DR. UHRIG: Thank you.
DR. POWERS: My recollection of a lot of this performance
stuff may be incorrect, and do correct me if I am wrong on this, that it
hinges upon finding indications and having a criterion for deciding
whether that indication is likely to fail over the next cycle or not.
And that, in turn, hinges upon having a database of indications, and
then tubes get pulled and pressure tested, and checked.
Where do we stand on that database?
MR. MURPHY: These databases, of course, are developed on a
degradation specific basis, and frequently they are also tied in to the
specific inspection methodology, and they are developed to support a
so-called steam generator, defect-specific management strategy, which
would normally include an alternate repair criteria or ARC.
So, you know, the people, licensees have incentive to
develop SGDSM programs and ARCs. It allows them the flexibility to
leave tubes in service longer, I assume it gives them more operational
flexibility, so that is their incentive for developing the appropriate
databases that are necessary to demonstrate, submit for NRC review and
approval that the methodology is satisfactory and does the job. It
ensures that the performance criteria will be met.
Now, there are many degradation mechanisms out there for
which we don't have SGDSM strategies and ARCs at the present time.
There continues to be an industry-wide database that gives us insights
on degraded tube behavior for generalized type defects out there. So
one is able to perform tube integrity assessments relative to the
traditional margin of three type criteria, or deterministic type
structural criteria, without developing new databases. But, you know,
he is motivated to go out and develop these new databases so that he can
have more liberal performance criteria, more liberal plugging criteria
that will enhance his operational flexibility.
DR. POWERS: What I don't have a feel for is the amount of
data that we have on, say, tube rupture during pressurization versus
some sort of a defect, by whichever detection may have been -- by
whichever type of degradation mechanism that is going on. Is this a
case of 10 or 15 data points, 10 or 15,000 data points? I am fishing
here because I don't know.
MR. MURPHY: Well, I would say, you know, I think that, you
know, we literally have hundreds of data points on a variety of
different defect types that allow us to have a good handle,
experimentally, on burst strengths as a function of defect side. Also,
you know, these tend to correlate very well with analytical methods that
have been developed to assess the damaging influence of specific size
flaws.
Where one might need to develop a new database, however, is
where -- a prime example was the voltage based criteria that were
developed for ODSCC at tube support plates. Now here it was being
proposed that the plugging criteria wouldn't be the size of the flaw, or
allowable size of flaw, but would be a voltage response. And so now you
have -- you know, the existing database doesn't help you understand
this, and I think it is the voltage role to burst strength and leakage,
so you needed really to develop a whole new database that allowed you to
make that kind of correlation. So the need for new data -- the fact
that you are proposing a new ARC does not necessarily mean you have to
go out and generate new data, but, depending upon the nature of the ARC,
you may have to. But there is a pretty extensive and robust database
out there already that covers pretty much the spectrum of flaws that we
have. There are a number of data points, I think it is in the hundreds.
DR. POWERS: When you say the database is out there, is
there a document that says the grand database that gets updated
periodically, or is it distributed all over the place?
MR. MURPHY: It is distributed all over the place. However,
specific degradation, like at ODSCC at tubes and core plates, there is a
central location, and we have an agreed-upon protocol with NEI as to how
that database is maintained and updated and disseminated to the
utilities.
DR. POWERS: How would I go about looking at it?
MR. MURPHY: In terms of the ODSCC database for voltage --
that supports voltage based criteria, one could look at the SCs written
for the individual plants and they reference, you know, an EPRI report
that contains the database. Okay. So in that case then there is an
EPRI report and if you would like, we can identify the EPRI report that
identifies the latest database.
With respect to other kinds of data, I mean we would have to
compile a list, I mean there is a lot of industry generated data. There
is data generated by PNNL, by Argonne and by others that are all
relevant to the integrity of degraded tubing, and so the list of
documents is quite long.
DR. SHACK: But just recently, for example, Diablo Canyon
came in with a new -- essentially, the data that demonstrate that sizing
capability for a particular type of flaw.
MR. MURPHY: Yes.
DR. SHACK: And so these things do come in.
MR. MURPHY: Yes.
DR. SHACK: The actually statistical -- you know, the
performance request that you are asking for is sort of in the draft Reg.
Guide.
MR. MURPHY: Right. But the list, you know, the list of all
the data that is out there that would help you understand the damaging
influence of a particular flaw, I mean licensees have developed their
own data, you know, run their own tests and run their own data. We have
the NSSS vendors do it. We have had other -- we have had national labs
do it and so this data is all over the map.
DR. SEALE: I hope that is a geographic map and not a data
spread.
MR. MURPHY: That is true, too.
DR. POWERS: I will bet there is a little bit of spread in
the data, Bob.
DR. SEALE: I bet there is, too.
MR. MURPHY: Okay. Well, just one closing comment regarding
the outstanding technical issues. The hard spot areas. A primary
reason these are hard spot areas is because there continues to be
discussion under how and when licensees may propose to implement
different criteria than the traditional criteria that have been -- you
know, the traditional criteria. And the issue that we have to confront
here is the potential risk implications of, for example, using
structural performance criteria that maybe are probabilistic criteria,
conditionally probability of rupture during steam line break, for
example, in lieu of traditional deterministic type safety factors such
as, for example, the factor of three against burst under normal
operating conditions.
Depending upon the circumstances during which the
probabilistic criteria might be implemented, there may be potential risk
implications, and this is, I think, the main gut of the outstanding
technical issues that we have with NEI and the industry today.
I think we're be talking about risk in a few minutes, if not
right away.
DR. BONACA: Just one question. As NDE techniques have
improved, for a period of time also new degradation modes were
identified.
MR. MURPHY: Yes.
DR. BONACA: Do you feel that that is pretty much -- we have
an understanding of all degradation modes that are there?
MR. MURPHY: I guess I have been working with steam
generators for 20 years and after that period of time I would never say
we saw the last mechanism.
[Laughter.]
MR. BARTON: Always a new one, right?
MR. MURPHY: There's always something new. There's always
surprises out there. It's amazing.
DR. POWERS: We have not exhausted all of the letters that
we can put in front of SCC.
DR. BONACA: But my next question in fact is how do you
correlate that -- I guess the uncertainty with this going to a new
criterion that would be probabilistic and trying to understand it.
You would go beyond a difficulty that not knowing what other
degradation processes that may be there that we don't understand because
of our ability to detect.
MR. MURPHY: Well, understand that under the status quo it
is our position that, well, everybody has a 40 percent plug-in criteria
they need to implement. That's applicable to all defect types, and it
is our opinion that when people are trying to assess whether their
program is working that they should be evaluating their structural
margins versus the traditional deterministic safety factors that are
consistent with the stress limits in Section 3 of the code.
If one wants to use alternate repair criteria to do the 40
percent work, one wants to do his tube integrity assessments to
different performance criteria, these would be done on a defect type
specific basis, and I don't just mean cracks versus thinning type flaws,
but they would be, these methods would be applicable to cracks at a
specific location, perhaps applicable to situations where noise levels
are no higher than "x" --
DR. SEALE: You would want the pedigree of the crack.
MR. MURPHY: Right -- I mean because the methodologies that
support the use of the ARC and the tube integrity assessments tend to
depend upon the NDE method that is being employed and its precision and
its accuracy and that very much depends upon the circumstances of the
specific flaws you are worried about, so the use of ARCs and the use of
performance criteria pretty much have to be defended relative to each of
the unique characteristics of flaws, of cracks, say at different
locations where they maybe occur and the NDE performance is different,
at expansion transition locations, for example, than it is in the U-bend
or the tube support plates and these differences need to be taken into
account to ensure that a ARC that is operable at a tube support plate
can be applied somewhere else for example.
DR. SEALE: I think we get the idea.
I have one more question. We have been sitting here or
teetering here on the brink for lo these many years now, I guess we can
say. When you and NEI finally resolve the outstanding technical issues
that still remain and so on, I think we would like for you to come and
tell us what the resolution of those are, things like burst margins and
things like that, because those are specific questions that you have
educated us so much on now that we just can't wait until we get the
answers to it.
[Laughter.]
DR. SEALE: So to bed. Well, I think that is all on steam
generator tubes.
DR. SHACK: Steve's got something.
DR. SEALE: Okay, Steve.
DR. SHACK: I don't think Steve is going to talk about
internals. I bet he's going to talk about tubes.
DR. SEALE: Okay. Well, we anticipated that we were maybe
fortunate that this was the last topic of the day. I mean this whole
set of issues.
MR. LONG: First of all, my name is Steve Long. I am with
the Probabilistic Safety Assessment Branch, NRR, and I have been asked
to make a fairly quick overview of the presentation that we made to the
subcommittee on the relationship of the requirements we have on steam
generator tube integrity to the risk from failures to have good
integrity.
You have the whole package of slides that we used for the
subcommittee. I don't intend to go through each of those. I will hit
about four of them and if necessary on questions we can go to the
others.
The genesis of this white paper was a meeting last October
in which there was sort of a general agreement between the industry and
NRC management participants that we needed to get the NRC's
understanding and position about this clarified.
We ended up producing a white paper and the Staff is
essentially serving the function of understanding the relationship of
what we now regulate to the control of the risk. It is essentially a
policy development process that is ongoing right now, so we have a white
paper that is in draft. He has not gotten far enough through the
concurrence chain for us to give you a copy. That was true for the
subcommittee -- it's still true now, unfortunately.
It is interesting that we keep being pulled away from the
development of the paper itself by plant-specific issues which then at
least help us focus on the issues that are in the paper, so I don't
think we are standing still but the prose hasn't caught up yet.
The subject is when and why to consider risk, as opposed to
how to consider risk. We think there has been quite a bit of progress
on how and if we can get the when and why straight, we can probably get
the guidance on how fairly promptly after that.
The paper contains a lot of material that is sort of
tutorial that I don't intend to go through with the committee but I do
want to say that as we --
DR. POWERS: Do you presume that we don't need to be
tutored?
MR. LONG: I think you have heard it all.
DR. POWERS: Oh.
MR. LONG: At least twice. It's referred to in the slides
and we can go through it if you wish with questions, but I just want to
note that as we go through that we have done a fair number of risk
assessments in the past where we have tried to include steam generator
integrity issues in the risk calculations and our findings have pretty
much been that the way we think we are regulating the integrity of the
tubes now does adequately control the risk but it is an indirect
control. It doesn't -- yes?
DR. APOSTOLAKIS: The title of your talk, when and why to
consider risk, you mean when and why to consider quantitative risk,
because you always consider risk.
MR. LONG: Let me reserve that to the end, but I think we
consider safety. We have words in the legislation and in the rules to
consider risk. How we consider risk has been qualitative to a large
degree in several respects in the past.
There is quite a discussion going on right now about how to
make that more quantitative, both the legal aspects and the technical
aspects.
DR. APOSTOLAKIS: But if it becomes quantitative there is no
question when and why -- then you must use it.
MR. LONG: You are getting right to one of the reasons you
don't have the white paper draft in front of you right now. The
guidance to the Staff is to try to use risk assessment to the maximum
extent supported by the state-of-the-art.
DR. APOSTOLAKIS: Quantitative risk assessment.
MR. LONG: Quantitative risk assessment -- probabilistic
risk assessment.
The regulations require us to find when an application is
submitted that we -- that the application meets our applicable rules and
regulations and also as a separately stated finding that there is
reasonable assurance of adequate protection to public health and safety.
The processes that are in place, the existing rules and
regulations don't explicitly include probabilistic risk assessment
processes and as we will get to in a minute, they seem to have so far
kept the risk down to a level that we are comfortable with, but as we
think about relaxing some of the existing controls it is not clear that
you can always just generally assume that will be the case.
You have to go back and look at the probabilistic
characteristics of the change and the difficulty with that is doing so
is not in our current procedures and practices We are trying to figure
out how to add that on and we are also trying to consider if when you
add it on quantitatively where is the threshold for acceptability.
We have some voluntary thresholds that have been agreed to
in Reg Guide 1.174, but right now the process allows the applicant to
essentially disregard that and to ask that it be done solely on the
deterministic processes that are written down and adopted.
If we get to a situation where we think it pretty much
complies with the written and adopted practices and procedures but we
think there is still an outstanding risk question, how we proceed in the
case is not yet really clear on the policy.
It gets to what's the definition of adequate protection, who
bears the burden of showing that there's a reasonable assurance that
there is adequate protection, or do we have to show that there's
reasonable assurance that there's not adequate protection in order to
deal with this? Those questions are still open for discussion.
At any rate, I think in discussing them, it's important that
people understand exactly what is controlling the risk right now given
the set of things that are written down, agreed to, and abided by the
licensees as they, you know, construct and operate and in-service
inspect their plants. So this table is laying out a lot of what we
think we're working with there and pointing out what controls risk and
what doesn't seem to have much of a handle on risk.
The structural integrity requirements in the ASME code,
either three times the normal operating delta P or 1.4 times the design
basis accident delta P, when applied to Inconel tubes, which are now
what's used in the steam generators, really helps not only minimize the
probability of bursting a tube in their design basis accidents, but
because of the extra margin, provides approximately enough capability to
withstand the severe accident challenges which involve higher
temperatures and approximately the same delta Ps as the design basis
accidents. I say approximately -- we're definitely in a no more margin
case for those particular sequences.
It looks like, for some plants with a high delta P, there's
a lot of margin, more potential for withstanding high temperature
sequences. For some plants with lower delta Ps or with thermal
hydraulics that present higher temperatures to the tubes more rapidly
during severe accidents, it looks like the margin is not quite enough.
Given the uncertainty in the process, it's just a close
call. I wouldn't want to say this plant definitely will or will not
have this sequence, survive with a flaw that just barely meets the ASME
code requirements. On the other hand, where we are right now is we
don't plug tubes exactly at the ASME code requirements; we try to find
tubes that have flaws that are getting large, project ahead with some
confidence that they will not exceed the ASME code requirements at the
end of the next cycle. If we aren't able to size them, size the flaws
very well when we detect them, we add some margin there.
So right now, what we're doing is a process that pretty
removes the flaws that we can find before they get close to or past this
ASME code requirement. So the process is kind of keeping us from having
a population of flaws in the generator that are likely to fail if you
ever have a severe accident challenge.
DR. POWERS: My recollection may be imperfect on this -- in
fact, it's sure to be imperfect -- but my recollection is that when we
had gross flow through tubes during the course of a severe accident --
that is, we had no loop seal, we were getting natural circulation flows
through them -- that we did overheat tubes.
MR. LONG: You're right in that there are some cases where
if you leave the RCS at high pressure -- and by high pressure, I mean at
least at the accumulator setpoint or thereabouts --
DR. POWERS: Sure.
MR. LONG: -- let the secondary side of the steam generator
depressurize, put natural -- a full look natural circulation through, we
think that you'll fail the steam generator tubes even if they have no
flaws. These hopefully have been small enough in frequency that it's
not putting the risk out of hand.
Now, if any one of those criteria isn't met, it looks like a
pristine tube at least will have a pretty good chance of survival.
DR. POWERS: And if we do have a loop seal so that we're
only going to get some sort of a convective transport through the tubes,
we concluded that we probably wouldn't fail tubes, but in coming to that
conclusion, we had relatively limited fission product deposition on the
tubes.
MR. LONG: Well, you came to the conclusion that a tube with
no flaw --
DR. POWERS: That's right. Yes. I'm speaking of flawless
tubes.
MR. LONG: Yes.
DR. POWERS: What's the story with a flawed tube?
MR. LONG: Well, as I was saying, with the flawed tube, the
flaws that are about at the ASME structural integrity requirement are
about where you would expect the strength requirement to be for this
convective counterflow in the hot leg heat transfer process.
DR. POWERS: My recollection is that the Japanese had been
looking at this area and that when they do the analyses, they come up
with much higher fission product loading on these tubes and a much
higher portion of the heat coming from the fission products.
MR. LONG: I'm aware of the study you're talking about. I
think Office of Research has looked at the study and run some Victoria
analyses and come to a different conclusion, but I'm not prepared to
speak in detail on those.
DR. POWERS: Is it a case that the Japanese now have an
experimental research program looking at this, or is this just the
battle between computer codes?
MR. LONG: I believe they have some experimental work, and
the question was whether or not it's applicable to the scenarios and the
accident sequences.
DR. POWERS: Do we have any forecast on outcome of this
debate or is this --
MR. LONG: I don't.
DR. POWERS: Okay.
MR. LONG: I mean, all I can tell you is we're aware of the
debate. I think there are others that are engaged in the debate, and as
I've asked are we changing our conclusion, the answer I'm getting now
is, not really.
DR. POWERS: If it's a battle between computer codes, maybe
we'll let them go ahead and argue with each other. If there's some hope
that we'll get some experimental data, then it seems to me that we ought
to be looking for that experimental data.
MR. LONG: I agree with that. I mean, I'm not in charge of
the Office of Research, --
DR. POWERS: Sure.
MR. LONG: -- but I do agree with you.
DR. POWERS: It would be nice to know what the hope is here
because fission product deposition on surfaces is a strange and arcane
field, and I'm a little bit out of my depth here, I admit. Dr. Kress
probably knows more about this than I do. It's easy to know more than I
do.
MR. LONG: Ed, am I correct in assuming there's nobody here
from Research that can address this, or Mike?
Okay. We just don't have anybody present today that can
address that.
DR. APOSTOLAKIS: The reason for the criterion there, how do
you know it's a minimum? You have a quantitative relationship or is it
just English language?
MR. LONG: Which minimum are you referring to?
DR. APOSTOLAKIS: The first under structure integrity,
reason for criterion?
MR. LONG: Minimize probability?
DR. APOSTOLAKIS: Yes. You're minimizing it really or
you're reducing it to a level where you're comfortable? Do you have a
quantitative relationship between the three times normal delta P and the
probability?
MR. LONG: If you can be sure you're succeeding at three
times normal delta P or 1.4 times accident delta P, then the failure
probability during the accident should be zero. So there's some English
in there as opposed to a mathematical expression if that's what you're
asking.
DR. APOSTOLAKIS: That's a minimum, all right.
[Laughter.]
DR. SEALE: Preclude is maybe a better word.
MR. LONG: Okay. I can fix that.
If we're ready to go to column 2.
DR. SEALE: Yes. Let's go right ahead.
MR. LONG: Okay. The other criterion that seems to have a
fairly large effect on controlling risk is to make sure that the leakage
during an accident is small. There are two things that now control
that. First of all, there is just sort of an assumption that one GPM
was a reasonable rate to which to keep leakage from a heat exchanger, so
one GPM was provided to the tech specs. It wasn't a derived value; it
was an input to the technical specifications and the design basis
accident analyses that were in chapter 15 and part of the licensing
process.
The tech specs later were developed to have a plugging
criteria for flaws that attempts to keep flaws greater than 40 percent
through-wall from occurring, and you can more than minimize, you can
preclude the possibility of a leak if in fact there's nothing that goes
more than 40 percent through the wall.
Again, if you were really successful in doing that, 40
percent through-wall looks like it will survive most of the
severe-accident challenges.
The idea in the licensing basis is to compare the postulated
accidents to a dose guideline that's in Part 100 of the regulations for
such postulated accidents, and the leakage rate from the primary to the
secondary typically does not include fuel damage, it typically -- with
an iodine spike and that's a much less challenging let's say requirement
than is a gross failure of the fuel cladding.
On the other hand, it's a potentially higher frequency
occurrence, so it's in the design basis.
If we meet that design basis and we do have the severe
accident, the 1 gpm leak rate may not be quite sufficient to make sure
you meet Part 100. It depends on how much scrubbing you can credit in
the secondary side, which normally isn't in the calculation.
However, it does look like it would keep the dose rate low
enough that the risk level to the population would be fairly well
controlled.
A couple of other things that are in our requirements but
don't really have very much effect on the overall risk to the public are
first of all the operational leakage, which started off at about 1 gpm,
perhaps apportioned among steam generators, but it was reduced in an
attempt to capitalize on the leak-before-break process to the extent
that it really occurs with steam generator tubes, and we feel it does to
some extent but not with a very high probability.
DR. POWERS: Could I come back to the second column under
your "would limit releases in severe accidents"?
MR. LONG: Yes.
DR. POWERS: When you say that, are you saying that because
it's only a gallon per minute, that's limiting it, or are you saying
that the growth over the course of the leakage that develops over the
course of the accident is such that it never gets up to the high levels?
MR. LONG: You're asking if a 1 gpm leak would essentially
cut open and give you a much larger leak rate during the course of an
accident?
DR. POWERS: Yes, I guess that's --
MR. LONG: Okay. I'll try to get to that, but now the idea
is if you can keep it to 1 gpm, it will limit the dose effect.
DR. POWERS: Okay. Okay, fine.
DR. SHACK: But you're really saying that because that's
limiting the population of flaws.
MR. LONG: Well, I'm really saying if you have no flaws that
go through a wall --
DR. SHACK: Right.
MR. LONG: Then there's no leakage. If you have small
pinholes that go through a wall and give you 1 gpm, that 1 gpm of leak
rate turns into some number of pounds of steam with associated fission
products involved leaking for the period of, you know, whatever time it
takes before you depressurize the RCS in a severe accident would not be
anything like a major bypass of containment during that severe accident.
It does keep the doses down towards the Part 100 guidelines as opposed
to up in the, you know, large 1400 PWR-1 type release categories.
DR. POWERS: I hope it's below PWR-1.
MR. LONG: It's definitely below there.
DR. POWERS: That's not a difficult bound to fall below.
MR. LONG: Okay. Third column. The point with 150 gpm is
that it does operationally give you the opportunity to prevent some
ruptures from occurring, but from the standpoint of really getting you a
frequency of failure of tubes under severe accident conditions, it's
quite possible to have flaws that are not leaking in normal operation or
leaking extremely tiny amounts become failures during severe accidents
if in fact the tubes heat up, experience a higher delta p flaw that's
not through wall may propagate through a flaw that is through wall but
is very tight, maybe with a ligament or two may pop open, a flaw that's
much shorter than critical length at normal operating temperatures may
be longer than critical length at higher temperatures and go ahead and
fail catastrophically. So you're getting a little bit, but not a whole
lot, from the operational leakage restriction.
DR. POWERS: Again, with trepidation, I may reveal ignorance
here, if a crack is below critical length at a low temperature, can it
become of critical length at high temperature?
MR. LONG: Yes. If a material flow stress or its ability
to, you know, withstand the pressure gets lower, a smaller flaw can go
ahead and tear it open.
DR. POWERS: The strength goes down, but doesn't ductility
go up?
MR. LONG: It's -- I'm not a materials person, but as I
understand, the ductility will go up, but it will essentially tear.
DR. SHACK: You get ductile tearing.
DR. POWERS: Okay.
DR. SHACK: Feel better.
MR. LONG: This isn't a brittle fracture mechanism. Inconel
is quiet tough material even at normal temperatures.
DR. POWERS: Even at high temperatures.
MR. LONG: Okay. Fourth column. The containment
calculations as they're done under chapter 15 analyses really don't
address a high-pressure core melt phenomenon. The containment does have
a different design basis than the RCS. It's there essentially to help
provide defense in depth if you haven't met the design bases for the RCS
and the ECCS, and historically we put a fairly large fuel clad failure
source term into containment at containment design pressure and require
that the leak rate of the containment keep the dose to the public down
below Part 100 criteria.
The calculation there usually explicitly takes credit for
the idea that it's a large LOCA that would cause that kind of fuel
damage. In a large LOCA the RCS pressure will be whatever the
containment pressure is. The pressure in the steam generator should be
whatever the safety valve set point or lower is. Any leakage will be
from the steam generator in. No need to calculate a source term by
leakage from the steam generator out to the public.
If you ask yourself what happens in a high-pressure core
damage sequence where that TID source term might be released into a
reactor coolant system that is at let's say the PORV set point or the
safety valve set point, and there is some potential for leakage out, to
the extent that you have the secondary side wet, it's scrubbed. To the
extent that that's really a station blackout core damage sequence, and
the secondary side may be dry, it's not scrubbed, but we don't treat
that in the design basis process. So this really does illustrate a
place where we're not tightly controlling the issue that we're concerned
about.
Next slide.
Some of the things that we've been asked to consider in the
way of changing these requirements are, first of all, to replace the
40-percent through-wall criterion with a criterion that would allow
through-wall cracks to remain in service as long as they don't leak and
they show that they can withstand, you know, the ASME code requirement
for structural integrity, which would be short cracks but through-wall.
The question is, would they become greater than critical length or would
they open up and leak a lot if they were exposed to severe accident
conditions.
That's a concern that's hard to address without some data.
We have some experimental processes to look at it. So far, as we've
discussed with you before, we really haven't approved anything like this
except where there's some additional confining capability like a drill
hole tube support plate or having it down in the crevice of a tube
sheet. So we still have an open -- couple of open issues with regard to
doing the same thing in the free span.
Associated with that have been requests for increase in the
accident leakage limit including a what's called a flex program that
would allow the licensee to essentially trade off allowable iodine
concentration in the coolant which is related linearly to the
concentration of radioactive material in the coolant during the design
basis accident against the leak rate in the design basis accident. The
difficulty with allowing that is that you can, if you drive the
allowable level for operation of the iodine in your coolant down to the
level that you can typically sustain it with good fuel, you can at the
same time relax the primary to secondary leak rate into the multiple
hundred gpm range and still meet this particular design basis accident
calculation.
What you are doing is you are saying that is not constrained
by this originally non-derived parameter of 1 gpm, you are going back to
the licensing basis calculations and using those to back calculate
something that was originally an input. If you do that, the problem is
leakage may be quite high in and of itself. In a severe accident, you
would not like to have multiple hundreds, maybe up to a thousand gpm
leak from one steam generator times two, three or four generators
perhaps with a severe accident type source term, as opposed to an iodine
source term -- iodine spike source term.
So that, again, is going to require some careful look before
we say the risk aspects of it are okay.
There is one issue that you brought up about leakage that we
also have discussed before and not really addressed, and that is if you
allow the leakage to be maybe even 1 gpm, but certainly multiple gpm,
and it is all coming from one leak, how big does that leak have to get
before the erosion of the leak itself, the heat flow to the leak,
because it is now no longer convective, it is forced flow, the cutting
effect of the jet coming from that leak and impinging on adjacent tubes
effectively leads to a gross failure of the steam generator boundary
with even higher than the predicted leak rate.
So, there may also be a need to not only limit total leak
rate but to go back and limit how much an individual maximum leaker can
be. And that partly gets into the definition that Emmett mentioned
about what is a burst and what is a leak. There have been some proposed
definitions of burst which are quite high. Something would be a leaker
if it doesn't exceed the charging flow of the system, which is typically
around 100 gpm, but there is one plant that I believe is 550 gpm. We
think some of the definitional problems have a bearing there as well.
And, finally, there is the request that the ASME code
requirement for structural integrity be replaced with a probabilistic
statement of structural integrity that addresses not the strength of the
ASME code level, but the strength directly at the design basis accident
level, and that a value of 5 percent is the conditional failure
probability during the design basis accident to be accepted.
We have a problem with that in the following sense. It not
so much that using a probabilistic criterion to address the strength is
at issue, the problem is that the level of strength is actually be
reduced substantially in the proposed criterion. We feel that we,
because of the way inservice inspection occurs with steam generator
tubes, we pretty much have to be somewhat probabilistic in the way we
interpret what is in the tubes and what will be there at the end of the
next cycle. So it is really the reduction in the strength level is a
concern.
DR. KRESS: Let me ask you a somewhat thinly disguised
question about these three? Would not your view as to whether or not
any of these three modifications were acceptable depend on level of CDF
that is actually achieved by the particularly plant that might want to
do it?
MR. LONG: Not so much the CDF as the -- I hesitate to call
it large early release frequency but the frequency of containment bypass
through the steam generator tubes is what we would really aim at. And,
yes, it would be --
DR. KRESS: But these are contributors to that?
MR. LONG: Yes. And the reason we are interested is that
frequency.
DR. KRESS: I am saying that there are allowing that to go
up a little bit maybe and, of course --
MR. LONG: The question is how much.
DR. KRESS: Yes. And, of course, how much you are going to
allow it to go up could depend on what the CDF, because it is also a
contributor to the LERF. It could be dependent on either the LERF or
the CDF, it seems to me like.
MR. LONG: Okay. I think as we have looked at this in the
past, if you relax the criteria, you may allow CDF to go up a little
bit, but we don't think that the effect on CDF --
DR. KRESS: It doesn't look like this would CDF very much.
MR. LONG: Not very much. There will be a small increase in
the CDF. Unfortunately, the part -- the increase in the CDF would also
be an increase in the LERF/containment bypass, whatever it really is by
definition, plus it may take some of the existing CDF and turn that also
into LERF where it was not LERF before. So our real focus is on how
much containment bypass CDF is created.
DR. APOSTOLAKIS: I don't understand this. We have been
using CDF and LERF. Now, you seem to be reluctant to use LERF.
MR. LONG: The difficulty with LERF is that LERF was
originally intended, and I think generally used, to say there is a class
of accidents that are much worse than the average, the bulk of the
accidents. They somehow bypass containment. They produce much higher
consequences than a core damage accident where the containment
essentially serves its function and contains most of the radioactive
material.
The difficulty with the regulatory process here is that if
you start going to something like the leak rate you can allow from the
primary to the secondary, you now have sort of a dial in the regulatory
process. If you want to play with that dial, you can essentially adjust
the effect on the public all the way from a contained reactor damage
accident all the way out to no containment, continuously, by how much
leakage you would allow.
DR. KRESS: That was the thin disguise I was talking about.
MR. LONG: At that point --
DR. APOSTOLAKIS: So how do you control that?
DR. KRESS: By CDF, that's why I said CDF.
DR. APOSTOLAKIS: He said CDF and you agreed that CDF --
DR. KRESS: No, I didn't agree, that is what he said. I
didn't agree that you couldn't use CDF to control it.
DR. APOSTOLAKIS: But the consequences is where you have the
impact, the CDF changes a little bit.
DR. KRESS: When you look at it, though, what you are
dealing with is a large uncertainty in that dial, and you could probably
deal better with that uncertainty if you had a much lower CDF, is what I
was --
MR. LONG: If you could get CDF --
DR. KRESS: Even though you end up with about the same, with
an acceptable LERF, you probably would rather that to be due to a small
CDF in the case where you had lots of uncertainty associated with this
part of it. This was the disguise I was -- my question. I figured you
two would pick up on it.
MR. LONG: What we are trying not to do, George, is have a
precise definition of LERF and then not worry about anything that falls
just barely short of that precise definitely, irregardless of the large
consequences on the public.
DR. APOSTOLAKIS: I am trying to understand whether the CDF
and LERF are the appropriate measures here, and whether there are any
sequences where --
DR. SHACK: Well, the sequence depends on having a core
damage accident.
DR. APOSTOLAKIS: Yes.
DR. SHACK: I mean you don't have damage accident, then
there ain't a problem. So if you get the CDF down low enough, --
DR. KRESS: Your LERF is low.
DR. SHACK: Your LERF is low.
MR. LONG: Sure. That is pretty hard to do, though. I
think you are better off trying to make sure that you have somehow
protected the tubes if you -- you know, during your CDF situation.
DR. BONACA: I just would like to go back to, you know, one
thing -- I mean here is a specific part of the plant that is difficult
to inspect, other than going back to this failure mechanism. So not all
locations are inspected. Typically, you go back and inspect those areas
that you know that have been affected. So there is a lot of unknown
about these tubes in certain regions. For example, it took years for us
to decide that we are going to inspect the cold side, and, lo and
behold, we found problems that we never thought were there.
Okay. So now we are inferring from testing a plant for the
next cycle, all right, and that is all we know. But we don't know
really what else is out there. So I am trying to understand still how
we can reduce this margin here by saying that, you know, the criterion
is going to come down significantly, you know, in this kind of scenario.
I mean I always thought that to some degree the fact that we had a lot
of margin, by going to the 40 percent criterion, gave us also some
comfort for what we don't know about these tubes. So I would like to
understand more about these alternate proposals here, because they don't
give me any comfort right now without hearing some more about that.
MR. LONG: I think you're saying what I'm saying. The
reason that I have listed these three things here, and there is a fourth
one I guess I should add, is that we think these things are potentially
challenging the finding that we have made in the past, that we think
risk is adequately controlled. With what we are doing now, we think if
we move to these things we need to look at them very carefully to see if
we can still draw that conclusion or if we have to limit them in some
way before we grant them to make sure we can still have some reasonable
assurance that the public is adequately protected, whether adequate
protection is LERF or somewhat short of LERF or what, is still a policy
discussion that is ongoing.
The fourth thing I should probably add is remember the slide
I said with Inconel tubes -- there's now actually a proposal to use a
different material as a sleeve that has different performance
characteristics under severe accident conditions, so that is yet another
thing that I think no one really thought of when we even wrote the white
paper less than half a year ago that we might be having to look at.
The conclusion from the risk assessment is really based on
everything that we are doing now -- the materials we are using not just
for the tubes but also let's say for the surge line. A lot of the
reason that the tubes survive is that the surge line doesn't -- is, you
know, it fails before the tubes do. If you made the surge line out of
Inconel the tubes would probably fail first, so changing anything very
substantially in what we are now doing may get you into a problem here.
DR. BONACA: What would be the advantage to a licensee to
allow for such large leakage?
MR. LONG: You are asking what is their incentive for doing
this?
DR. BONACA: Yes.
MR. LONG: Basically economics and the uncertainty of the
inspection process.
When inspections are done with the tubes, the inference of
what is there and how fast it grew to get there for this inspection and
therefore trying to infer the size of things that you have at the next
inspection at the end of the next outage, is very uncertain, so trying
to show that there is not -- trying to show that you can actually find
everything that might be a problem at the end of the next cycle may be
difficult. The licensees spend a lot of money doing it.
In particular, if they have to shut down at a short cycle
and just do an inspection without doing refueling, that costs them a lot
of money. The inspection process is expensive and the not producing
electricity is expensive. Replacing generators, plugging generator
tubes, sleeving generator tubes is expensive, so this is really a large
economic burden on the licensees and to the extent that you can reduce
the burden and maintain safety, you know, it's in everybody's interest
to try to do that.
DR. BONACA: But wouldn't you have to change all your
programs? For example, based on the leakage rate you have a lot of
analysis that have to be redone and certain limits, control room and
everything else is affected by that.
MR. LONG: There are some things we are doing that -- let me
get to the last slide here.
DR. SEALE: Let's hurry it up here.
MR. LONG: I'm trying. Okay. There are a few things that
we think are worth doing. One of them is there is no guarantee for
instance that 1 gpm was the right number with regard to protecting the
public, so there's work going on at the Office of Research now to
investigate as a parameter what the dose consequences are, multiple
measures of dose consequence to the public given reactor accidents with
various levels of primary and secondary leakage.
When we get the technical information there is then a policy
question of how much consequence is too much consequence for saying that
your containment performance has been achieved as being allowed to
improperly degrade, so we can get just so far with the technical
information we can provide.
Some of it is going to be uncertain and even to the extent
that we knew it perfectly there's policy questions that are yet to be
resolved.
In the interest of speeding it up, I think I should just ask
for questions at this point.
DR. APOSTOLAKIS: It seems to me that Slide 8 --
[Laughter.]
DR. POWERS: Don't laugh, because I am going to go to 5.
DR. APOSTOLAKIS: The English language should be modified.
I think if you look at the penultimate statement there, the key to
controlling risk is use -- and so on.
The reason for that is that we cannot really quantify the
impact on risk from degradation of steam generator tubes. Is that
correct?
MR. LONG: The thrust of this is to say we cannot do it
precisely enough to regulate to a limit that is a computed risk.
DR. APOSTOLAKIS: So we cannot quantify. That is really
what it is.
MR. LONG: Yes.
DR. APOSTOLAKIS: So that comes back to my earlier comment
about when and why to consider risk. If you can quantify it, you
consider it. If you cannot quantify it, you resort to deterministic
requirements.
MR. LONG: Why you resort to them, but I am saying the
risk-informed process, you can use a risk assessment with the
uncertainty associated with it if you can show that you are clearly not
at risk or you clearly are at risk. You have done something
quantitative.
If you are somewhere in the middle, you can at least
establish which parameters look like the level of risk is sensitive to
them and then you can try to put your deterministic controls on those
parameters.
DR. APOSTOLAKIS: I am stating that in a different way. I
am saying that I wouldn't say that risk assessment will clearly
demonstrate something is safe or unsafe, but if I cannot really quantify
the impact on my matrix from the degradation of steam generator tubes,
then I have to resort to other means.
In other words, it is not sensitive enough, the PRA, right
now the way it is.
MR. LONG: It is not precise enough, you are saying.
DR. APOSTOLAKIS: Precise?
MR. LONG: It may not even be accurate enough but certainly
two good PRA analysts can get in a room and argue virtually forever
about whether the number is different by a factor of two.
DR. SHACK: George, you can compute risk up the wazoo to 13
decimal places but that doesn't control risk. I mean the way you
control risk is to keep the number of flaws --
DR. APOSTOLAKIS: But can you really calculate it? I doubt
it. Degradation --
DR. SHACK: Well, I mean that is a Gedanken experiment.
Even if you could compute it, you don't control risk that way. You
control risk by keeping the population of flaws small. The thing that
keeps the population of flaws small --
DR. APOSTOLAKIS: I keep trying to go back to that paper on
defense-in-depth.
DR. KRESS: I know, and I am too.
DR. APOSTOLAKIS: And I don't think we should have a million
principles here.
DR. KRESS: No. I don't think so either.
DR. APOSTOLAKIS: This is a case in my mind where the PRA is
incomplete. We have a steam generator tube rupture initiating event but
we are talking about the frequency per year. We are not talking about
individual or groups of tubes failing or being degraded. That is way
beyond what a PRA does, so now you say, well, gee, the PRA doesn't do
that, I resort to traditional methods, prescriptive methods.
MR. LONG: I don't think --
DR. APOSTOLAKIS: I think that is perfectly all right.
MR. LONG: -- we are saying quite that. I think what we are
saying is that actually you can put that into a PRA now. There's
uncertainties when you do it. Oregon Gas & Electric is doing it. We
have done it to some degree, so it is just a matter of when you do it
the result you get is not something that you can take to the bank on the
first significant digit any more than any other piece of a PRA.
DR. KRESS: What he is saying is that the uncertainties are
too large to be acceptable. You either reduce the uncertainties --
DR. APOSTOLAKIS: Right.
DR. KRESS: -- or you reduce the CDF. Since the CDF is what
it is and you don't reduce it, they reduce the uncertainties by this
process.
DR. APOSTOLAKIS: Right.
DR. KRESS: That is what they are doing, reducing the
uncertainties.
DR. APOSTOLAKIS: That's right. I agree with that but I
wouldn't use those statements about PRAs useful to demonstrate that
something is clearly safe when risk assessment is not precise enough to
define a regulatory limit. I don't know about all these things.
The uncertainty is large enough, I resort to
defense-in-depth and safety margins.
DR. SHACK: I don't think you are reducing uncertainty. You
are reducing the failure probability of the tube.
DR. SEALE: That's right.
DR. KRESS: You are doing both.
DR. APOSTOLAKIS: Both -- you are doing both.
DR. SHACK: Yes. If I reduce the failure probability of the
tube, I reduce the uncertainty but I mean --
DR. KRESS: But you are doing two things. You are reducing
LERF by doing that, and you are also reducing your uncertainty a little
bit because you are able to calculate within whether the tubes are going
to bust or not better as you do these sort of things. You are
increasing your ability to both reduce LERF and reduce the uncertainties
and you get both of them to a level you are comfortable with is what
he's saying.
DR. APOSTOLAKIS: Yes.
DR. SEALE: Are there any other questions?
DR. KRESS: And that is the right way to use
defense-in-depth.
DR. APOSTOLAKIS: Yes. Exactly.
DR. POWERS: It seems to me that the statement being
entirely accurate, if I look at the PRAs we have available to us today,
I don't think there is an inherent flaw in PRA technology that forces us
into the deterministic requirements here.
I think some people just haven't done it.
DR. KRESS: I would agree with you.
DR. POWERS: I think it could in principle be done and done
well and I think that we run into difficulties deciding what appropriate
margins are because we don't have that kind of risk information.
DR. KRESS: But they are related to the uncertainties.
DR. POWERS: It seems to me that we -- I know that when we
have tried to set up the event trees for the NUREG 1150 effort there was
a lot of talk about let's go in and work the steam generator issue for
what's called the progressing accident, because, yes, we have a steam
generator rupture accident as initiator but we became very concerned
about progression of the high pressure sequences which we knew were risk
dominating in the NUREG 1150, that they would progress toward the steam
generator tube --
We did go back to the Quest study which looked at how
pristine tubes responded to the accident, and all that lead to not doing
this. But I was convinced at the time and I'm convinced now that you
can do this, and that we're as this data base that they're talking about
grows the imperative for doing this seems to me to grow higher because
until you do that, you have no idea whether these deterministic
requirements with what are called appropriate margins are good enough.
DR. FONTANA: Wait a minute. I don't have any problem with
the penultimate statement there. No matter how good your PRA is, I
don't see any problem with developing requirements on how you're going
to build and inspect and maintain tubes and the amount of time that you
allow a plant to run -- to fail to meet these margins. You can
determine these things on the basis of PRAs.
DR. POWERS: What we're saying is that yes, you can in
principle, but you can't now in fact.
DR. SEALE: Or we haven't in fact.
DR. POWERS: We haven't up till now because I think nobody's
worked the problem.
DR. SEALE: That's what I mean.
DR. POWERS: And I think we're getting a data base here that
ought to allow us to do this.
DR. FONTANA: So you don't really have an issue with that
statement.
DR. POWERS: I think it's entirely accurate if I take the
current state of the art. I think it's terrible that we don't have
people trying to advance the state of the art here, because this is a
thing that's been around. Since 1989 for sure people were concerned
over this and said we can do this, but they didn't go ahead and do it.
Now they probably couldn't have done it in '89, but we're getting an
awful lot of data that looks to me like it sets up an awfully nice
probabilistic model.
MR. LONG: Let me say that we have been trying to advance
the state of the art since 1150 on this subject, and there's been
industry as well as NRC work to do that, but the point of the slide was
we think with the best that we're doing now and the best that we expect
to be able to do in the future, we don't believe that we can set a risk
value and say that however you show that your PRA comes out below this
number, it's acceptable. But if it comes out above this number by any
number of significant digits off, it's not acceptable. We just don't
feel that it's a precise enough tool to regulate that way.
We also found when we did 1074, released it for public
comment, the industry was saying just the probabilistic part of
projecting ahead to the end of cycle was something that they had a very
hard time doing because of the uncertainty of what the flaw was once
they saw a signal for it in the ISI process. So we there really this is
addressing that problem.
We're saying that what we really think we need to do is try
to figure out what the sensitive parameters are, try to control them
with some deterministic processes that we feel comfortable to keep the
risk reasonably well controlled, and even if the licensee is exceeding
the criteria that we choose, the deterministic criteria that we choose,
we want them set in a place where as long as they're there for just a
short period of time, the risk will still remain low, as we believe it
does now rather than put the burden for precise statistics on ISI.
DR. POWERS: This is all regulation by religion. I don't
think you've got the kind -- I mean you're saying I feel comfortable.
You haven't seen enough severe accidents and the progression of those
severe accidents into the steam generator to have a defensible basis for
your comfort.
MR. LONG: I think you're right in the sense that it's hard
to generate that level of comfort, and every time you think you've got
it, somebody brings up some other subject. So you're right, it's
difficult, but I think we have tried to do what we can with the
information we have now.
DR. APOSTOLAKIS: That's true. That's true.
MR. LONG: And our conclusion is we don't really see a big
problem right now that we think we should be backfitting. Now tomorrow
maybe somebody will walk in the door from Sandia or wherever and say
look at this problem and we'll be in backfitting space. But right now
we don't --
DR. POWERS: Sandia never comes up with problems, only
solutions.
[Laughter.]
DR. APOSTOLAKIS: I want to understand something here,
because I was told earlier that because of the bypass nature of these
accidents, containment bypass, you want to control the core damage
frequency, because core damage has to occur first.
MR. LONG: Well, what I was really --
DR. KRESS: That was Dr. Kress.
DR. APOSTOLAKIS: Well, Dr. Shack, too, said in order to
have -- you have to have core damage.
MR. LONG: But we aren't trying to make core damage
frequency so low that it doesn't matter if the tubes fail.
DR. APOSTOLAKIS: Well, but that now creates a new problem.
What you're saying is that you will have an additional goal for core
damage frequency, aren't you, the 10 to the minus 4 is not good enough
for you because of the special nature of these core damages.
MR. LONG: We're saying that --
DR. APOSTOLAKIS: That drives me up the wall again.
MR. LONG: Well, there's already a criterion for large early
release which is different from core damage.
DR. APOSTOLAKIS: Right. But you can't use LERF. You said
you're not going to use it.
DR. KRESS: This is captured in large early release.
MR. LONG: We're saying we're treating this as if it's LERF
as far as that's concerned, and there may be some quibbling about
whether it exactly meets the definition of LERF.
DR. SEALE: What he's saying is that the margin between LERF
and CDF is in part due to the fact that you have these deterministically
established relatively conservative criteria for steam generator tube
plugging and so on, and that if you relax those, you may very well be
bringing those two nearer to each other.
DR. POWERS: There was a time when people became very
concerned that all core damage accidents would progress to --
DR. SEALE: Would be steam generator --
DR. POWERS: Steam generator tube rupture.
DR. SEALE: And then they're the same.
DR. POWERS: And then LERF and CDF are exactly the same.
That's right.
DR. SEALE: Yes. Yes.
I think we beat this horse as tired as we can beat him.
DR. POWERS: No, we haven't.
[Laughter.]
DR. KRESS: Turn to page 5.
DR. POWERS: I'd like to just touch on page 5 just for
clarification. I'll avoid discussion. I get to discuss this later.
Say new risk-informed limit on accident leakage could be
developed. It needs to address defense in depth. Okay. This is a
containment boundary that we're discussing here. That's an element of
defense in depth. Why should defense in depth be applied to an element
of defense in depth?
MR. LONG: I'm not sure I understand the question, so --
DR. POWERS: See, I don't understand the sentence, so --
MR. LONG: What we're really saying is that we're trying to
step away from the risk equation itself and ask just the consequences
part of the question to address the defense-in-depth issue, so if we
start playing with this dial that's the leak rate from primary to
secondary during a high-pressure core-melt accident, and we're not going
to let it go so far that it essentially just rips apart the
primary-to-secondary boundary, but we're letting it leak maybe through a
myriad of little, tiny leaks for a certain amount until the RCS fails
inside containment at least.
We're really asking not is my frequency times my
consequences an okay number, we're trying to look just at the
consequences and saying if you want to preserve defense in depth, how
much leakage can we allow through this containment boundary -- part of
the containment boundary -- before you're really seriously degrading the
defense-in-depth function, before you're really saying a lot of the core
damage accidents that used to be successfully contained in our models
now have a pretty sizable consequence, and it's because we allowed it to
be a sizable consequence, not because the physics prevented us from
stopping the sizable consequence.
DR. POWERS: Well, to keep the discussion track and to
assure that I get the last word on this, that seems to me that this is
an appropriate risk question and not a defense-in-depth question.
DR. KRESS: It seems to redefine defense in depth in my
mind.
DR. APOSTOLAKIS: And I -- well, it redefines it in many
ways when you spell it with a "c," but the last paragraph, in order to
apply the -- I don't understand it -- to apply the guidance in RG 1.174
it will be necessary to determine appropriate accident leakage limits
such that the containment function is not substantially compromised
during accidents that are not in the LERF category.
DR. POWERS: That one I understand. That sentence I have no
trouble with.
MR. LONG: Reg guide 1.174 says consider the risk value --
DR. APOSTOLAKIS: Right.
MR. LONG: It also says maintain defense in depth. There
are quantitative acceptance criteria for the risk increases. There is
no quantitative value for change in the defense in depth. We're trying
to figure out how to address that. But the point of the sentence is to
say we have to develop some sort of policy there, because there is none
right now, other than maintain defense in depth, but we don't think that
means don't let the consequences go up by 1/100 of a percent. We're
trying to figure out what's adequate defense in depth and what's not.
DR. APOSTOLAKIS: Accidents that are not in the LERF
category, what are these accidents?
DR. POWERS: I think -- my interpretation, and please
correct me if I'm wrong, was exactly what Bob was saying, that staff has
looked around and says okay, I've got CDF here, and I like numbers like
10 to the minus 4 and CDF, don't like higher numbers, like lower numbers
even better. I've got LERF at 10 to the minus 5. I like numbers less
than 10 to the minus 5, don't like numbers that are bigger than 10 to
the minus 5. Okay? There is a presumption that the ratio of core
damage accidents that lead to LERF is about the same in all plants, as
we've calculated up to now.
If we have degradation of our steam generator tubes such
that those accidents that used to involve failure inside of the
containment now involve failure of the pressure boundary at the steam
generator tubes and become LERF accidents, that is, they have a large
early release, if that ratio starts getting very, very different than
what we found in the past, then suddenly these numbers are no longer
good guidelines for you anymore.
DR. APOSTOLAKIS: So now you are going to control these
accidents so that the CDF that results from these initiators will be, in
fact, substantially lower than 10 to the minus 4, isn't that the natural
conclusion from this?
DR. POWERS: It already is.
DR. APOSTOLAKIS: It already is.
MR. LONG: We think with the current controls we have in
place that the LERF is in the low 10 to the minus 6 range from this kind
of accident.
DR. KRESS: These are differential contributions by
sequence, and the CDF for a given sequence like this is pretty low. I
mean you add them all up to get the 10 to the minus 4.
DR. APOSTOLAKIS: Right.
DR. KRESS: And so these --
DR. BONACA: These are sequences that right now don't
contribute LERF. What happens is that because of the failure --
DR. SEALE: Get closer to the microphone, Mario.
DR. BONACA: I am saying that those are sequences right now
that contribute to the LERF category. What you are saying is that if
you allow them to release significantly to ruptures, they would add to
the LERF category, that is what you are saying. You would increase your
LERF category by a significant amount by adding sequences for which
right now you have assumed no failure of steam generator tubes.
DR. APOSTOLAKIS: I have to understand. Is there a place
where I can read about this?
DR. POWERS: I will talk to you offline about it.
MR. LONG: If we can get the -- well, there is 1570, but if
we can get the white papers, we will make sure you get a copy of that.
It is a little clear than the slides.
DR. APOSTOLAKIS: Okay.
DR. SEALE: Any other questions that are absolutely burning
a hole in people's chair?
[No response.]
DR. SEALE: Do you want to take a little short break before
we go on? Or should we let Mike go first?
DR. POWERS: We have more presentations?
DR. SEALE: We have one more.
DR. POWERS: Why don't we take a 15 minute break then?
DR. SEALE: If that is all right with you.
MR. MAYFIELD: Let me offer at least a proposal.
DR. SEALE: Okay.
MR. MAYFIELD: What we can do is leave the handout with you,
given the lateness of the hour, leave the handout with you. Steve had a
quick 10 minute -- or four slide presentation, it burned off the better
part of an hour. I foolishly had the work "risk" on my slide. I
figured about a half hour, so God only knows how late this might go. I
would propose to you that we might leave the handout with you and come
back in June after we have met with the industry on the PTS program, and
we can at least at that point give you an update and give you a look at
how the program is starting to shape up.
DR. APOSTOLAKIS: We will have this document by then, right?
We will have read this document by then?
MR. MAYFIELD: I have no idea.
DR. SEALE: That has nothing to do with this. This is --
DR. APOSTOLAKIS: It has nothing to do with this.
DR. KRESS: This is PTS.
DR. APOSTOLAKIS: A separate issue.
DR. SHACK: Just that it has got risk and he knows that
creates problems.
MR. MAYFIELD: I have been forewarned.
DR. POWERS: And to be quite honest with you, Bob, I would
like to go through PTS rather carefully.
DR. KRESS: Rather than hurry it up.
DR. SEALE: I have no argument with that.
DR. POWERS: Quite honestly, I want to have a good
understanding on PTS and what is going on there, and not -- I have
gotten lots of snippets. I now need to have somebody take me from top
to bottom and say what is and what should be.
DR. APOSTOLAKIS: So you are supporting the suggestion then?
DR. POWERS: Yes.
DR. APOSTOLAKIS: Okay.
MR. MAYFIELD: So we need to put this off and try and get
back on your agenda, I would suspect in June or July.
DR. POWERS: July would be better for us.
MR. MAYFIELD: The only thing I would ask is don't put me on
after Steve.
[Laughter.]
DR. SEALE: The only thing I will point out to you,
gentlemen, that this is actually part of a -- well, it is an
introduction to a process which has embedded in it a fair amount of ACRS
interaction with the staff. And so you will not be getting that --
let's say a high sign on what some of the details of that interaction
are going to be until July.
DR. POWERS: Well, it is because there is a lot of ACRS
interaction here that I would like to start the process off with a
pretty thorough grounding on this, beginning even fairly elementary.
MR. MAYFIELD: We will come back and give you whatever
briefing you would like to have. I have to say because of the way we
have gotten this program up and going, since we are going to be moving,
you know, April 20th and 21st is the first meeting with the public, to
talk about how we are going forward and to actually start some of this
process. It is going to extend over a couple of years and we
anticipated visiting with you a number of times during that period of
time. But we will be up and moving between now and then.
DR. SEALE: There is a significant thermal-hydraulic
component, by the way, to the overall program.
DR. POWERS: Oh, dear. Just make sure your documents are in
good shape.
DR. SEALE: Mike, I apologize.
MR. MAYFIELD: No problem.
DR. SEALE: I knew we were going to get in trouble when
these guys put their planning and procedures hat back on. Bill and I
got scolded. It is back to you.
DR. POWERS: Okay. Sam, is Sam here?
MR. BOEHNERT: I can get him.
DR. POWERS: More importantly, are the by-laws here? Would
you distribute the by-laws, please?
DR. SHACK: Well, if we are not going to have a
presentation, are we going to have a break?
DR. POWERS: You will get a break shortly. I just have to
do a couple of little functions. Dr. Kress, you have the floor. You
were supposed to be making a motion quickly.
DR. KRESS: Okay. I forgot where we were. I make a motion
that the members -- I make a motion that these by-laws be approved.
DR. POWERS: Do I have a second for this motion? I really
need a second.
DR. WALLIS: Without any question?
DR. SHACK: Second the motion so we can go on to discussion.
DR. WALLIS: Now we can discuss.
DR. POWERS: Now, the motion -- we have a motion on the
floor for discussion. What I would like to do is to table that
discussion and allow the members to review these by-laws over the course
of the next three days. If you have comments and whatnot on them,
please submit the written comments to Sam for corrections and we will
propose taking a vote on this motion on Saturday morning, first thing
off the bat.
DR. MILLER: I move we postpone till Saturday morning. I
move we postpone till Saturday morning.
DR. POWERS: There is a movement to postpone the vote.
DR. SHACK: Second.
DR. POWERS: All in favor of the motion? All opposed? Now,
we can take a break till 5:30.
[Whereupon, at 5:17 p.m., the recorded portion of the
meeting was recessed, to reconvene at 8:30 a.m., Thursday, April 8,
1999.]
Page Last Reviewed/Updated Tuesday, July 12, 2016