ML20148B159
| ML20148B159 | |
| Person / Time | |
|---|---|
| Issue date: | 05/06/1997 |
| From: | NRC COMMISSION (OCM) |
| To: | |
| References | |
| REF-10CFR9.7 NUDOCS 9705120197 | |
| Download: ML20148B159 (107) | |
Text
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2"'?;NAL
- o UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
Title:
BRIEFING ON PRA IMPLEMENTATION PLAN -
PUBLIC MEETING s
Location: Rockville, Maryland Date: Tuesday, May 6,1997 Pages: 1 - 86
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t DISCLAIMER This is an unofficial transcript of a meeting of
- the United States Nuclear Regulatory Commission held on May 6, 1997 in the Commission's office at One White Flint North, Rockville, Maryland. The meeting was open to public attendance and observation. This transcript has not been reviewed, corrected or edited, and it may contain' inaccuracies.
The transcript is intended solely for general informational purposes. As provided by 10 CFR 9.103, it is l not part of the formal or informal record of decision of the matters discussed. Expressions of opinion in this transcript do not necessarily reflect final determination or beliefs. No pleading or other paper may be filed with the l Commission in any proceeding as the result of, or addressed i
to, any statement or argument contained herein, except as the Commission may authorize. l i
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1 o 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 - - -
4 BRIEFING ON PRA IMPLEMENTATION PLAN 5= - --
6 PUBLIC MEETING i 1
7 1 l
8 Nuclear Regulatory Commission 9 One White Flint North !
10 Rockville, Maryland )
l 11 ;
I 12 Tuesday, May 6, 1997
.13 14 The Commission met in open session, pursuant to 15 notice, at 2:05 p.m., Shirley A. Jackson, Chairman, 16 presiding.
17 18 COMMISSIONERS PRESENT:
19 ' SHIRLEY A. JACKSON, Chairman of the Commission 20 KENNETH C. ROGERS, Commissioner 21 GRETA J. DICUS, Commissioner 22 NILS J. DIAZ, Commissioner 23 EDWARD McGAFFIGAN, JR., Commissioner 24 25 ANN RILEY & ASSOCIATES,-LTD.
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1 STAFF AND PRESENTERS SEATED AT THE COMMISSION TABLE: *
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2 ANNETTE VIETTI-COOK, Assistant Secretary of the i 3 Commission 4 KAREN D. CYR, General Counsel !
5 EDWARD JORDAN, Deputy EDO 6 SAMUEL COLLINS, Director, NRR 7 GARY HOLAHAN, Director, Division of Systems Safety-and i 8 Analysis, NRR 9L CARL PAPERIELLO, Director, NMSS f 10 ASHOK TRADANI, Deputy Director, RES 11 THOMAS KING, Deputy Director, Division of Systems 12 Technology,-RES ;
13 DENWOOD ROSS, Director, AEOD 14' !
15 ,
16 i
17-18' 19 '
20 21 22 23 24 25 l
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1 PROCEEDINGS
-2
[2:05 p.m.)
3 CHAIRMAN JACKSON: Good afternoon. I'm pleased to 4
welcome members of the NRC staff to brief the Commission on 5
the status of the NRC PRA implementation plan. The PRA 6_ implementation plan was first' issued in August 1994. The 7
plan is intended to be a management tool to help ensure the 8
timely and integrated agency-wide use of PRA methods and 9 technology in the agency's regulatory activities. The last 10 written update on the status of activities in the PRA 11 implementation plan was provided.to the Commission in 12 January of this year. The Commission was last briefed on 13 the plan in October 1996.
14 During today's briefing the staff will discuss 15- recent accomplishments in particular where they have made q 16 risk-informed decisions. They will discuss revisions to the 17 PRA implementation plan, draft regulatory guidance for 18 public comment, performance monitoring and pilot I 19 applications, - other pilot projects, - and plans for future i 20 activities, 1 i
21 The draft regulatory guidance documents and 22 standard review plan sections provide guidance on acceptable 23' approaches for making plant-specific risk-informed changes I l
24- to the current licensing basis of a nuclear power plant'in a l 25 specific area. The staff is recommending that these 1
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4 1 documents be issued for a 90-day public comment period. -
2 I and my fellow Commissioners are looking forward 3 to your briefing today. I understand that copies of the 4 viewgraphs are available at the entrances to the room.
5 If none of my fellow Commissioners have any 6 opening comments, Mr. Jordan, please proceed.
7 MR. JORDAN: Thank you, Chairman, Commissioners.
8 Our briefing this af ternoon will focus on the documents that 9 were forwarded to the. Commission by SECY-97-077. We will 10 also discuss selected achievements described in the il quarterly status update, SECY-97-076, which was issued April 12 3, and then in SECY-97-095, which is the tech spec program.
13 With me at the table today are Ashok Thadani and
'14 Tom King from the Office of Nuclear Regulatory Research; Sam 15 Collins and Gary Holahan from Nuclear Reactor Regulation; 16 Carl Paperiello from Nuclear Material Safety and Safeguards; 17' and Denny Ross from the Office for Analysis and Evaluation 18 of Operational Data.
19 All of the focus of this presentation is on the 20 regulatory guide standard review plan. Dr. Ross and 21 Dr. Paperiello are here representing their offices' 22 important roles in the PRA program plan and can respond to 23 . questions related to AEOD and NMSS PRA activities.
24 As you know, Ashok Thadani has recently assumed 25 the position of Deputy Director of the Office of Research.
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. 1 CHAIRMAN JACKSON: Congratulations.
2 MR. THADANI: Thank you.
3 MR. JORDAN: In this new capacity he will continue 4
to be responsible for overall coordination and monitoring of 5
the agency's PRA program plan and will begin today's
. 6 briefing.
7 MR. THADANI: Thank you.
8 .May I have viewgraph number 1, please.
?
9 [ Slide.]
4 10 MR. THADANI: As you noted, Chairman Jackson, and 11 Ed Jordan did as well, this is clearly an activity where all 12 the program offices are involved. The focus of today's )
13 briefing is going to be in three areas: the regulatory 14 guides, the quantitative measures that we propose be 15 utilized, the status of the pilots, and the issues related 16 to performance monitoring.
17 I will very briefly go througn some of the other 18 issues to indicate that work is going on in other areas as 19 well, but our focuc is going to be on those three areas.
20 I will cover the background and some of the recent 21 accomplishments as well as where we are on the 22 implementation plan. Then Tom King will go through the 23 draft regulatory guidance, the criteria, and what we are 24 doing by way of posing a set of questions to get feedback 25 from the public as well as industry.
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6 1 After his presentation is complete on the PRA -
2 portion, he is also going to touch upon the issue that came 3 up at the last meeting with the Adviaory Committee on 4 Reactor Safeguards, the issue of human data and coordination 5 of that activity. Chairman Jackson, you had asked that we 6 address that issue.
7 Gary Holahan will cover the performance monitoring 8 and pilot applications and describe our future actions.
9 May I have the next viewgraph, please.
10 [ Slide.]
11 MR. THADANI: We have been providing quarterly 12 reports to the Commission on status of the implementation of 13 the activities described in the plan as well as semiannual 14 briefs to the Commission on status of these activities.
15 At the October briefing we covered some of the 16 policy issues. These were issues, like should safety goals 17 be used on plant-specific basis or should small increases in 18 risk be allowed?
19 The Commission was also provided in January a 20 status report on the activities and the plan.
21 January 22, 1997, the Commission provided guidance 22 to the staff on those key policy issues. As we had 23 indicated to the Commission, we were moving in the direction 24 of using those guidelines and the guides. After we received
. 25 the Commission SRM on this issue we finalized our guidance ANN RILEY & ASSOCIATES, LTD.
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.- 1 documents to make sure that these documents were consistent 2
with the guidelines described in the safety goal policy 3 statement, the regulatory analysis guidelines documents, and 4
other related documents.
5 We met with the Advisory Committee on Reactor 6
Safeguards as well as the Committee on Review of Generic 7
Requirements and have got their endorsement for these guides 8
and documents to be issued for public comment.
9 In April, as Mr. Jordan noted, we provided to the 10 Commission two documents, a status of the implementation 11 plan, SECY-97-076, as well as SECY-97-077, which is a fairly 12 thick document. It includes the general regulatory guide, 13 the standard review plan, and topic-specific guides like 14 graded QA, in-service testing, and so on.
15 In that-document we also provided a draft Federal 16 Register notice and highlighted the set of questions we 17 proposed that we get feedback on from the industry as well 18 as the public.
19 May I have the next viewgraph, please.
20 [ Slide.]
21 MR. THADANI: These are just some examples of some 22 of the recent accomplishments. Obviously the reg guide and 23 the SRPs have been provided to the Commission. They provide 24 framework and guidance for making changes to licensing basis 25 of individual plants. Tom King is going to say a great deal ANN RILEY & ASSOCIATES, LTD.
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i 1 about that.
2 Another report that we recently sent to the 3 Commission was the technical specification pilot 4 application. This is working with the Combustion 5 Engineering Owners Group wherein they had proposed changes 6 in' allowable outage time in the area of safety injection r 7 tanks. These are basically passive tanks. They wanted to 8 change allowable outage time from one hour to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and e
9 low pressure safety injection train outage time from three 10 days to seven days, r
11 We have used an approach consistent, as described 12 in the regulatory guide, and provided a safety evaluation
~13 report approving those allowable outage-time extensions.
14 That information has been given to the Commission for 15 .information. If there are any questions or concerns, of 16 course we will address them.
17 The approach we used there was to work with the 18 lead plant. Arkansas Unit 2 was the lead plant. There are, 19 I believe, ten plants that would be interested in these 20 changes. We would expect to issue our evaluation on those 21 ten plants by the end of July 1997.
22 CHAIRMAN JACKSON: You expect to issue?
1 23 MR. THADANI: Safety evaluation reports, July of 24 1997.
25 I will note that there are one or two questions ANN RILEY.& ASSOCIATES, LTD.
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- j. 1 that we are going to have to deal with for one or two r i 1 1 2 plants,-because it appears in some cases the calculated mean i
- 3 core damage frequency is higher than 10 to the minus 4 per j 4 reactor year. That is an element that.needs further !
i 5 discussion. Outside of that, we expect to be able to issue j i 6 the safety evaluation reports approving those extensions in
'7 allowable outage time. f 8 In February we issued NUREG-1021, Revision 8, i
9 which is the operator licensing examiner standards. These 10 standards have now in them a number of the insights that l have been gained through risk assessment studies and they 11 j 12 have become-part of the training program as well as :
T
- 13 examination portion. They identify, for example, dynamic !
i 14 testing considerations, pick up the more significant l
15 plant-specific accident sequences to see if they are covered !
- 16 'through simulated training, et. cetera.
j 17 All of those issues are now captured in this
. 18 revision. It was published in-February of 1997, after the (
! 19 Commission approval was received in December 1996.
1 i 20 CHAIRMAN JACKSON: Can you say how the guidance 1
- l 21 documents themselves were informed by the pilots or the IPE l i-
' l 22 reviews, if they were?
23' MR. THADANI: The guidance documents give a number 24' of insights and lessons. You'will' hear some of it.
- 25 MR. KING
- I was going.to cover that as part of 1 4 ;
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2 CHAIRMAN JACKSON: You are going to cover it in 3 your presentation?
4 MR. KING: Yes.
5 MR. THADANI: Yes.
6 CHAIRMAN JACKSON: Okay.
7 MR. THADANI: But we can come back to it again to j 8 make sure.
9 CHAIRMAN JACKSON: We'll wait.
10 MR. TRADANI: May I have the next viewgraph, 11 please.
12 [ Slide.]
13 MR. THADANI: If it appears I am moving quickly, I 14 am, so that we have an opportunity to go through some of the 15 issues that I know you are very interested in.
16 As you know, AEOD staff has been working on 17 evaluating voluntary approaches to reporting reliability and 18 availability data and the feasibility and practicality of 19 that approach, and we expect to have a paper to the l
20 Commission in the next few days and anticipate that there 21 will likely be a separate briefing as well on this topic.
22 We have also conducted a workshop on the insights 23 from the IPE program and we have a briefing tomorrow 24 afternoon on IPE, and we will cover some of the lessons and 25 things we have learned tomorrow afternoon during that ANN RILEY & ASSOCIATES, LTD.
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. 1 briefing.
2 CHAIRMAN JACKSON: Let me ask you for the 3 Commission's edification. What were the objectives of the 4 IPE workshop and were they met?
5 MR. THADANI: I would ask Tom King to address 6 that.
7 MR. KING: There were several objectives. One was 8 to give the industry an opportunity to ask questions 9 regarding what we felt were the important insights from the 10 IPE, to provide information on things they have done since 11 the middle of their IPE. Most of those submittals were 12 years ago. It gave us a chance to talk about our IP 13 follow-up activities, which you will hear about tomorrow.
14 Ultimately, we understood the industry had been doing some 15 IP insights work themselves, and it gave them an opportunity 16 to present to us what they had been doing on their own 17 initiatives.
18 So it was a multipurpose workshop.
19 CHAIRMAN JACKSON: Let me ask you a question about 20 your first bullet, your evaluation of the voluntary approach 21 for reporting reliability and availability data. What would 22 be the scope of that voluntary approach? How many SSCs, 23 systems, structures and components, and how does it compare 24 in terms of the number of risk-significant SSCs in a plant, 25 and if the scope is different than the scope of the ANN RILEY & ASSOCIATES, LTD.
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i 12 l 1 maintenance rule, why so? -
2 MR. THADANI: Dr. Ross.
3 MR. ROSS: Of course this will be covered in more !
4 detail in the paper. The description that we got from INPO !
I 5 shows up very nicely on an embedded diagram, sort of like a l l
6 bin diagram, where the safety system performance indicator 7 is embedded into a larger group of maintenance rule, 8 safety-related and other equipment. It would be covered by 9 -INPO but not part of the maintenance rule itself.
10 The voluntary approach would consist of 11 af the 11 information under the safety system performance indicators i
12 .and other information. As we will explain in the paper, it :
13 does contrast with the scope of the proposed rule that went i 14 out. Our arguments will show where the two are different, .
15 how we intend to make up for the differences. s 16 CHAIRMAN JACKSON: So the answer'to the question 17 is, the scope is different than the scope of the SSCs in the ;
18 maintenance rule? i 19 MR. ROSS: The scope of the voluntary approach?
20 CHAIRMAN JACKSON: Right. That's what I'm talking 21 about. !
22 MR. ROSS: I believe in detail, yes. In terms of 23 types of information.
24 MR. JORDAN: Maybe I could comment. The scope of '}
25 the maintenance rule'is very large. The scope of the i i
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. 1 reliability data rule was relatively narrow. The scope of 2 the data that would be obtained and used includes the 3 principal data elements from the reliability data rule plus 4 access to additional data for other systems and components.
5 So we are continuing to structure the scheme of analyzing 6 the data consistent with the reliability data rule, but 7 there is not a deficiency in the scope.
8 CHAIRMAN JACKSON: You are answering questions the 9 way I anFwer them. Let me ask it this way. What is the 10 overlap between the scope of SSCs that are covered in the 11 maintenance rule and the scope in this voluntary approach?
12 Not the voluntary approach vice the reliability data rule, 13 but the voluntary approach vice the maintenance rule.
14 MR. THADANI: If I may just comment on this, I 15 don't think the answer is very crisp. However, it is fairly 16 clear that even within the -- first of all, the proposed 17 rule scope of systems is fairly narrow.
18 Let me just now go to the maintenance rule scope, 19 which is very broad. It includes SSCs, both safety-related 20 and non-safety-related, covering various aspects. Then the 21 industry is to convert these SSCs into high 22 safety-significant and low safety-significant categories.
23 The focus all along of the agency efforts has been to make 24 sure we have information on high safety-significant 25 component.
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14 l 1 Then you go to the voluntary program. The desire , ,
2- clearly would be to try and get information to cover those t
3 SSCs that have high safety significance. That could be a !
i 4 plant to plant variable. I think that issue is going to l 5' need some further evaluation, and I think you are going to j 6 see in the paper discussion the need to do some more 1 7 evaluations to be able to give a crisp answer.
-8 CHAIRMAN JACKSON: For a given plant, will the f 9 scope of the SSCs covered in the voluntary approach be a 10 subset of those most safety-significant SSCs in the '
11 maintenance rule, or is it not that crisp?
12 MR. THADANI: I think it will clearly be a subset. !
13 CHAIRMAN JACKSON: Where does the lack of ;
i 14 crispness lie? l i
15 MR. THADANI: The lack of crispness is.in that ;
i 16 clearer definition that all of those SSCs are in fact- i 17 covered in the voluntary program, t 18 MR. ROSS: Chairman, one of the ways we are going l l
19 to' break down the answer, matrix or table is looking at the ;
20 parameters such as failures -- all of these comments are j
21 under the voluntary approach -- then showing how failures, 22 for example,.would be provided for the small-set known as 23 .the safety system performance indicator and then how would 24 they be covered for everything else of high safety ,
25 significance under the maintenance rule. This matrix is
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. 1 developed for failures, demands, run times, and so on.
2 It's a rather complicated answer, but I think we '
3 have covered it all in this table.
4 MR. JORDAN: I think we owe you that discussion in 5 a broader presentation.
6 CHAIRMAN JACKSON: I think you do.
7 MR. JORDAN: It is not terribly simple.
8 MR. TRADANI: Quite honestly, that is why I 9 thought it was likely that there will be a need for a 10 briefing on just that topic.
11 May I have the next viewgraph, please.
12 [ Slide.]
13 MR. THADANI: During this three month period we 14 did not really make any major changes to the plan. However, 15 I do want to touch upon some of the schedule or issues and 16 briefly cover the status of the pilots, and then we will 17 have some additional discussion as we go through.
18 What has happened basically is the whole process 19 of developing these documents, making sure that the agency 20 is involved and supportive of what we are trying to do, as 21 well as our interactions with various committees. I think 22 the Advisory Committee on Reactor Safeguards as well as CRGR 23 has taken a lot of effort and time, more so than I think we 24 had anticipated. That has had some impact. We have had to i
i 25 take time away occasionally from pilots to make sure we j l
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16 1 dealt with those issues. -
2 I do want to summarize where we stand on these 3 pilots. I indicated that the technical specification,
'4- safety evaluation report is complete, and that we would 5 expect to issue the remaining safety evaluation reports for ;
6 other CE plants in July of 1997.
l 7 We have a team, as we speak now, at South Texas !
1 8 working on the graded QA program. Our expectation is that 9 barring some surprises from this visit we expect to finish !
10 our safety evaluation report by the end of June of 1997. [
11 In-service testing is yet another pilot that.we i
12 have been working on. We have recently put together a set i 13- of additional questions to make sure that what we are doing 14 under IST is in fact completely consistent with what we are ;
15 saying in the regulatory guides. We expect to get fairly f
16- quick responses to those questions and complete our i 17 evaluation by the end of June of 1997. :
18 The fourth pilot activity was in-service i
19 inspection area. The in-service inspection, in my view, is .
20 probably more challenging in terms of the issues on ;
21 methodology than some of the other pilot applications, ;
22 because now you'are getting into areas like trying to get an 23 . idea -- incidentally, the scope of ISI is piping, all 24 classes of piping. You need information on flaws, flaw 25 -distributions, fracture mechanics. These are more ANN RILEY & ASSOCIATES, LTD.
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17 1 contemporary approaches in terms of models.
2 We have been working with the industry on two 3 approaches. One is the ASME Westinghouse approach, which is 4 very probabilistic in nature; another approach from Electric 5 Power Research Institute, which is less dependent on 6 numerical analysis and more qualitative type of importance 7 analysis type of an approach.
8 While have been working on the methodology issues, 9 we have not received any submittal from any of the pilots.
10 We expect Surrey to come in in September, using the ASME 11 Westinghouse owners group methodology. It appears that 12 perhaps Arkansas, and I think Fitzpatrick, may also come in 13 using the EPRI approach.
14 Clearly you will hear through the presentation 15 that in terms of in-service inspection we cannot complete 16 our final document until we have actually gone through the 17 pilot application. However, we do have a draft guide that 18 we expect to get to the Commission in July. That will go 19 out for public comment and those will be the ground rules 20 that we will apply as we go through the pilot evaluation.
21 CHAIRMAN JACKSON: Do you plan to add any 22 risk-informed performance-based initiatives to the PRA 23 implementation plan?
24 MR. THADANI: I don't know of any specific plans.
l 25 The Commission asked us in an SRM to not just be limited to ANN RILEY & ASSOCIATES, LTD.
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18 1 performance-based thinking as far as the PRA implementation -
2 plan is concerned and that it may be necessary to develop an 3 implementation plan for performance-based thinking in other 4 applications. If I remember correctly, we owe the 5 Commission that response end of August, and we are working 6 on that.
7 CHAIRMAN JACKSON: So you are going to address it ;
8 at that time?
9 MR. THADANI: At that time. As part of that 10 activity we would be meeting with the industry to solicit 11 their views in this area.
12 CHAIRMAN JACKSON: This was asked in the context 13 of another meeting, but I will ask it again within this 14 context. It seems that there is some delay. We had 15 discussions about the development of risk-based indicators, 16 and the question is, what impact do you think any delays in 17 developing the risk-based indicators will have on plan 18 schedules for their use in the senior management meeting 19 process?
l 20 MR. ROSS: Obviously we have taken a good'look at !
)
21 the replacement set for the current PIs with risk-based '
22 indicators. I think it would probably have a moderate 23 effect. I was looking at one of them in.particular. We !
24- have a very deterministic approach to significant events i
25 now, when an event can be called significant. One concept ANN RILEY & ASSOCIATES, LTD.
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, 1 to replace it is using a tool like ASP to make a more 2 quantitative description of what is a significant event. I 3 don't think it will be perfect. I think there will be some 4 significant events that it will still quantify low.
5 I would expect this would have a moderate effect 6 on the senior management meeting. The admonition is we are 7 not supposed to be overly influenced by singular events. I 8 think with that precaution I would expect it to have at 9 least a moderate effect. Whether it takes somo additional 10 risk-based training to understand this and criteria to 11 understand what is and what isn't significant, I think it 12 would probably take some additional training as well. These 13 are supposed to be phased in, according to the plan, by 14 1999.
15 I IR . JORDAN: The present set of indicators we felt 16 have been risk informed, but now this is really a transition I 17 to the risk based. l 18 CHAIRMAN JACKSON: Since we are talking about the 19 PRA implementation plan, for the record I would like to hear 20 from Dr. Paperiello on where we stand in terms of the 21 development of PRA or like methods in your areas, fuel cycle 22 facilities, industrial devices containing nuclear materials, 23 et cetera.
24 MR. PAPERIELLO: Could I have the backup slides 25 for materials?
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20 1 [ Slide.] .
I 2 MR. PAPERIELLO: We have worked in several 1 3 different areas. You are going to have a presentation next 4 week on performance assessment in both high level waste, low 5 level waste and decommissioning. Performance assessment in 6 those areas looks much like PRA in the sense that you have !
7 models, you have inputs with, instead of discrete values, a 8' range of values.
9 For example, if you look at Yucca Mountain, in a 10 PRA sense it will be rain or no rain, because that is a 11 significant factor in the model. For Yucca mountain you 12 don't have that. You have a range of rainfalls. So that 13 becomes a distribution that goes into the model rather than i
14 a yes or no or up or down value.
15 What comes out is identical to what comes out of a 16 PRA. You have a risk distribution or dose distribution, as 17 you will, that is characterized by a 95 percent confidence 18 level and 5 percent confidence level, a mean, a median and a 19 mode. You can choose how you are going to measure. We use .
i 20 median values, for example, in reactor space. We have a i
21 tendency to use mean values for what we do in. performance !
22 assessment. So there is that group'of things.
23 We have used PRA methods or risk-based methods in 24 transportation. The modal study done several years ago. We 25 are looking at that and using it to iterate the existing ANN RILEY & ASSOCIATES, LTD. l Court Reporters l 1250 I Street, N.W., Suite 300 Washington, D.C. 20005 (202) 842-0034
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, 1 NUREG-0170, the EIS on transportation that was done in the 2 late 1970s, to update it with the insights in the modal 3 study, 4 At our request Research is initiating a plan to 5- apply PRA to spent fuel storage facilities. We are looking 6 at methods to look at the risk associated with industrial 7' gauges containing cesium 137 and cobalt 60, and we have 8- developed an integrated safety assessment procedure for fuel 9 facilities to assess the risk from chemical safety, critical 10 safety and fire safety integrated. So they.are the 11 activities we have undertaken up to now in applying PRA in 12 the NMSS side of the house.
13 We hcve in our budget plans in the future to 14 actually set up a PRA group in NMSS to see how we can apply 15 it in all our areas.
16 CHAIRMAN JACKSON: Can you have the slides shown 17 again, please?
18 .[ Slide.]
19 CHAIRMAN JACKSON:- When do'you expect.to'come to 20 ' closure? Let's leave aside the high level waste repository.
21 For instance, on your next to the last bullet,-or the ones 22 involving transportation,.but particularly the ones to 23 demonstrate methods for PRA of spent. fuel storage facilities 24 or for determining the risk associated with industrial 25 gauges, when do you' expect to come to closure on some of ANN RILEY & ASSOCIATES, LTD.
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22 1 these? -
2 MR. PAPERIELLO: On the gauges, I'll have to ask.
3 MR. COOL: Good afternoon. The contract for that 4 particular action with Research is scheduled for the summer 5 of next year, that is, summer of 1998.
6 CHAIRMAN JACKSON: Thank you.
7 MR. THADANI: If I may just make a quick comment.
8 In reactor applications, the Commissio'n's safety goals and 9 the all the guidance of the Commission has given the staff 10 is to utilize mean values and not median. I just want to be 11 sure that there is not a misunderstanding of that. We are 12 using mean values, and I think it is very important that we 13 use mean values in these analyses.
14 Unless you have other questions, I'm going to go 15 to Tom King.
16 MR. KING: If I could have slide 6, please.
17 [ Slide.)
18 MR. KING: Slide 6 through 14 provide a summary of 19 the reg guides and SRPs that were provided to you in ,
20 SECY-97-077.
21 What I want to do in the briefing is focus on the 22 overall approach and key issues associated with those 23 documents. Just a little background information.
24 As you recall, the specific plans and schedule for l 25 developing these draft documents were put together after a ANN RILEY & ASSOCIATES, LTD.
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23
. -1 November 30, 1995, request from Chairman Jackson. The 2 purpose of these documents is intended to help implement the 3 Commission's PRA policy statement by providing guidance on 4 an acceptable approach for making plant-specific, -
5 risk-informed changes to the current licensing basis of 6 nuclear power plants.
7 'The documents include general guidance, which 8 provides an overall approach in.guidan'ce applicable to all 9 risk-informed proposed CLB changes.
l 10 Then there is supplemental guidance in specific -
11 areas that are shown on the viewgraph. The supplemental 12 guidance is not a replacement for the general guidance; as 13 it says, it supplements the general guidance.
14 Also included in the package was draft NUREG-1602. j 15 This was prepared as a reference document to aid in making ;
16 decisions on the scope and attributes of a PRA that would be 17- appropriate in proposing a risk-informed change to a CLB.
18 Chairman Jackson, you had mentioned where the IPE -
19 had really helped influence this package. This is probably 20 the.most prominent area where we took IPE. insights in terms 21 of strengths and weaknesses of PRA methods, databases, and 22 so forth, that the industry used and folded them into the 23 guidance that is in that draft NUREG.
24 CHAIRMAN JACKSON: When using the guidance 1
25 documents, will the staff be able to use the documents to ANN RILEY & ASSOCIATES, LTD.
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24 1 judge the quality of a PRA-based submittal? .
2 For instance, let me give you some questions.
3 Will they be able to judge whether the appropriate s 4 models were used, appropriate data used, appropriate common 5 cause models used, appropriate human performance modeling, 6 or distributional assumptions? Can you make some comments 7 in those areas?
8 MR. KING: The answer is yes to all of those. The 9 intent of having the draft NUREG and the guidance in the reg 10 guides and SRPs is to answer yes to all of those questions.
11 COMMISSIONER ROGERS: Before you leave that, one 12 question on the CLB. The work that you have done to date 13 concerns looking at using risk information for changes to 14 the current licensing basis. How far would that approach 13 take you, or could you use that to actually restructure the 16 CLB on a risk-informed basis itself?
17 MR. KING: Go back through the regulations and see 18 what would change if you apply risk insights. I think 19 clearly starting with the safety goals and using metrics 20 associated with core damage frequency, accident prevention 21 and mitigation, the containment type requirements, would be 22 used in any such process. We haven't really thought about 23 taking this reg guide and are the metrics we developec for 24 it appropriate for such an analysis, but I think where you 1
25 start from would be the same, the overall guidance. i ANN RILEY & ASSOCIATES, LTD.
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25 1
- i. CRAIRMAN JACKSON: It might be worth considering.
2- MR. THADANI: We do have other areas, Commissioner i
e 3 Rogers, as~you know, that look at some of the regulations to 4 see what sort of value there is in some of those 1
5 requirements. In making judgments there, it seems to me we l
i i 6 would have to use the same sort of thinking and be i-1 -- 7 consistent as we go forward.
8 COMMISSIONER ROGERS: That's a bigger job.
9 MR. THADANI: A much bigger job, yes.
- . 10 COMMISSIONER ROGERS
- It's always a little easier r
11 to look at incremental effects. But the general approach 12 that you have had to adopt in analyzing changes, that may '
13 have given you some first steps towards what one might have 1 14 to do in restructuring a CLB on a risk-informed basis.
1
{ 15 MR. THADANI: Yes.
4 1
16 CHAIRMAN JACKSON: The guidance documents call for 17- increased management attention when changes approach certain
- l. 18 guidelines. You lay them out: core damage frequencies in a 19 certain range with deltas of a certain size. Is it clearly 20 spelled out what increased management attention means in the 21 guidance documents? Otherwise, can you end up in a case '
22 where an approved pilot becomes-the de facto standard 23 guidance? i 24 MR. KING: There is a set of items-that should be 25 looked at when you are in that increased management '
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26 1 attention region. It deals with things like recent plant -
2 performance, recent operating events, uncertainty analysis, 3 sensitivity analysis, scope of the PRA, things like that 4 that are highlighted. As you get closer to those guideline 5 values you want to take a closer look at what is going on in l
6 terms of what is the uncertainty range, how do you deal with 7 it, what other qualitative factors may influence my decision 8 one way or the other.
9 MR. THADANI: I would just add to that that the 10 thought process as you get closer and closer to these 11 guidelines. The degree of robustness of the analysis would 12 have to go up, and greater attention has to be paid to 13 issues of defense in depth or what does that really mean; is i l
14 there a great deal of reliance on human actions? !
15 You asked a question in terms of value of IPEs, 16 human reliability issue. We can give guidance and-the best i 17' available techniques. The recognition is still there that 18 there are very large uncertainties. Those are going to be 19 difficult to deal with, particularly if we have a plant 20 whose performance we are very uncomfortable with. Core 21 damage frequency may be very low; the change in core damage 22 . frequency, while it may be small, we can't lose sight of the 23 fact that the agency is concerned about performance of that ,
24 plant. Those factors have to be integrated, and the 25 management has to play a significant role in that.
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l 27 1 MR. KING: If I could have slide 7, please.
2 [ Slide.]
4 3 MR. KING: As you heard ACRS say last Friday, we 4 had some extensive interactions with them in developing 5 these regulatory guides. They felt it was constructive; we 1
6 felt it was constructive. We feel the guides are much 7 better off for that give and take and frank discussion we
{
8 had with ACRS.
9 We also had similar discussions with CRGR. With I 10 the pilot programs we had interaction back and forth. The I 1
11 pilots provided some real world examples on the types of 1
12 changes that the industry will be asking for. The 13 practicality of the risk metrics and other traditional 14 engineering type criteria or guidelines that we propose, is
- 15 it practical to apply them? Do they cover a wide range of 4
16 the types of changes that we believe will be coming in 17 proposed by the industry?
18 Also, it had a chance for us to interact with the 19 industry on expectations in terms of the quality and scope 20 and depth of their analysis. We felt there was a broad 21 range of feedback that we got from the pilots in that 22 respect.
23 To get back to the IPEs for a minute, they 24 provided some examples also in terms of the value of the 25 risk metrics that we proposed. We could see from them what ANN RILEY & ASSOCIATES, LTD.
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.28 e
- r 1 their baseline core damage frequencies were, for example,
- l' ,
i 2 where they made changes based on their IP, what they i i
3 represent in terms of core damage frequency and other risk 4 metrics. So there was some valuable feedback from that as 5 well. !
6 COMMISSIONER ROGERS: Could you make'any comments -
7 about the nature of the interactions with CRGR and what came 8 out of those?
9L MR. ROSS: I can respond. In the first place, ;
10 this was not an imposed backfit. So we noted that. So 11 50.109 really was not triggered. We noted it was what we
-12 call a measured step along the path towards risk-informed
[
13 regulation. Small but measured.
14 At that point you could say our strict CRGR role 15 was complete. We reviewed the imposition of requirements.
16 But we also have a value added. role, and we.noted that we- '
17 are really talking about fairly small numbers. In some e
18 . cases even smaller increases in these small numbers, and it
- 19 .might'be difficult to characterize this as a change within -
20 the general feeling, especially as you get close to 10 to 21 .the minus 6.
-22 'We noted that there'had been due consideration of i
23 the safety goal, and by and large we thought it was a good 24 step. .We thought the staff in the period that we dealt with 25 them over a few months did an incredible amount of work, and s ANN RILEY & ASSOCIATES, LTD.
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29
. 1 we so said. We complimented them on the give and take and 2 the cooperative effort. It was a large job for them.
3 COMMISSIONER ROGERS: Thank you.
h 4 MR. THADANI: Let me note that CRGR views are the
}
5 last two pages in this document, summarizing basically what 6 Denny said.
7 MR. KING: Finally, before we leave slide 7, as 8 you noted, Chairman Jackson, the package is at the 9 Commission for approval. Included in that package is a 10 Federal Register notice, which has a series of-topics from 11 which we would like feedback. It also indicates our 12 intention to hold a workshop during the public comment 13 period. We now have that scheduled for the third week in 14 July. It will be here at NRC headquarters, in the 15 auditorium. So we are anxious to get that out on the street 16 and let people make their plans to attend.
17 CHAIRMAN JACKSON: See how it floats.
18 MR. KING: Slide 8, please.
19 [ Slide.)
20 MR. KING: In developing these documents we had 21 several fundamental questions which had to be addressed 22 early in the program so that we could establish and settle
-23 in on an overall approach for these. documents.
24 Specifically, we.had questions regarding where do 25 these documents fit in the overall regulatory process, what ANN RILEY & ASSOCIATES, LTD.
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30 1 is the benefit to licensees and the staff of using these .
(
2 documents, and how do we maintain consistency with l
3 Commission policies and practices.
l l 4 We have settled in on an approach that basically 5 puts these documents forth as one acceptable method for 6 licensees to propose changes to their current licensing
.7 basis where NRC approval is required. These do not affect 8 50.59 type changes. In effect, they provide an alternative 9 way to utilize risk insights when licensees propose changes 10 under 10 CFR 50.90 through 92, which is license amendments.
11 Since these documents were written basically as a 12 result of a PRA policy statement, we consider them voluntary 13- on licensees. However, we have taken the approach or are 14 taking the approach that using risk insights will be done by 15 the staff in reviewing proposed changes to a plant CLB. So 16 even if licensees come in and don't utilize risk insights, ,
17 the staff is still free to ask questions regarding risk.
18 The benefits to the licensees and to the staff I 19 think we expressed well in the PRA policy statement: ,
20 improved decision-making, more efficient use of resources, 21 and the potential for reduction in unnecessary regulatory 22 burdens. So we feel there is certainly.an incentive for 23 both licensees and staff to use these documents.
24 Finally, we spent a lot of time trying to make 1 25 sure that these were developed consistent with previous l
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31
. 1 Commission guidance and policies, one particular item I 2 will note in that regard was the definition of the current 3
licensing basis that we chose to use, which was straight out i
,4 of 10 CFR Part 54, our license renewal rule. We feel that's '
5 a good definition. We feel it certainly can fit well into 6
the context of these documents, and that's what we propose 7 to use.
8 Slide 9, please.
9 [ Slide.]
10 MR. KING: At our last semiannual briefing we put 11 a slide up that talked about a six-step review process. Our i 12 six-step review process is now a four-step review process. !
1 13 We haven't eliminated anything, but we have l 14 recognized that what we call engineering analysis, you can't 15 really separate the traditional engineering from the 16 -probabilistic from the integrated decision-making. It 17 really has to be done together and it complements one 18 another.
19 So structurally we have rewritten the document to 20' basically be a four-step review process, the steps you see 21 on the slide here.
22 We-feel that the implementation and monitoring 23 program is still a very key element in all of this. It's 24 important to verify the validity of assumptions and analysis-25 and provide a vehicle for feedback and corrective action if ANN RILEY & ASSOCIATES, LTD.
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32 1 we find out from real plant data that things aren't turning -
2 out the way we were expecting. So it's an important part of 3 this process.
4 CHAIRMAN JACKSON: Let me ask you a question.
5 Since you are saying that one would have to do the overall 6 engineering analysis that has the three pieces you have 7 outlined,'have we ended up adding a layer of analysis net 8 net? I was going to say for ourselves, but I'll say for 9 yourselves since you are going to do the analysis. Can you
, 10 give me an answer to that?
11 MR. KING: Clearly you can view it as, well, now 12 we have to do PRA on top of everything else, but I don't 13 think that's the right way to look at it. I think the right 14 way to look at fus PRA helps you make judgments on what is 15 important in the traditional engineering analysis. You may 16 have~been spending a lot of time trying to meet a limit that 17 turns out isn't very important and maybe you can be relaxed 18' somewhat. I think it's a way in the long run to be more 19 efficient and to improve what we are doing.
20 MR. THADANI: I would like to add to that. We 21 have been using-risk-informed thinking in a number of ways 22 when some of the license amendments come in and they propose 23- relaxations. More and more we have tried to obtain insights i
24 from risk assessments, to see before we grant those 25 relaxations to make sure we are not approving a change that ANN RILEY & ASSOCIATES, LTD.
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33-
- . 1 could.have significant risk implications.
} 2 I think it has been done by and large in an ad hoc 1
3 What this does is produces the right 1 manner up to now.
4 infrastructure, a level playing field, so to speak, not only j 5 for the industry but the staff as well to give guidance to 1
4 6 both sides as to what would be a reasonable way to go 1
)
1
.7 . forward. Yes, in some cases that does mean additional '
8 analyses would.have to be conducted by the licensees. )
9 CHAIRMAN JACKSON: I noted in what you sent to the 10 Commission you say that these documents apply for 11 risk-informed, applications, but there is this performance 12 monitoring program associated with each application. So 13 what has to happen to make the applications both risk 14 informed and performance based? l 15 MR. THADANI: We are going to cover that. That is !
16 part of what Gary Holahan was going to cover. You.had 17 specifically asked, I think in the last SRM, that we should I l
18 discuss that issue, t
'l 19 CRAIRMAN JACKSON: We will wait. '
'20 MR. KING: If.I could have slide 10, please.
21 (Slide.]
22' MR KING: Slide 10 starts with the top level or 23 -general guidance that is.in the draft general reg guide, and !
1 l24 it's.also applicable to the application-specific reg guides. j 25 Basically, the top level guidance is stated in-1 ANN RILEY & ASSOCIATES, LTD. )
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34 1 terms of five fundamental safety principles that are -
2 intended to preserve the essential element of NRC's 3 regulatory philosophy, policies and practices, and to ,
)
4 accomplish the integration of the traditional-engineering 5 along with the risk insights.
6 The five items are shown on the viewgraph. Let me 7 just say a few words about them.
8 First, licensees are expected to meet'the 9 regulations or propose a change or an exemption if their 10 proposal'needs such a change or exemption. We don't view 11 these regulatory guides ~and SRPs as a process to circumvent 12 the regulations. I want to make that clear.
13 Second, defense-in-depth has certainly been a 14 philosophy to assure safety and reliability in plant systems 15 and features, and'certainly a way that has been used to 16 account for uncertainties in the past. Therefore we think 17 maintaining the defense-in-depth philosophy is important.
18 We believe that PRA can provide a useful role in 19 looking at the extent of defense-in-depth. We have provided 20 some additional guidance on what we mean by 21 defense-in-depth. For example, defense-in-depth is thought 22 of in some respects as a balance between prevention and 23 mitigation. Clearly PRA can play a role in trying to 24 quantify and illustrate is that achieved or'isn't that L25 achieved. We don't view defense-in-depth as strictly ANN RILEY & ASSOCIATES, LTD.
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35
. 1 engineering judgment; we think PRA can provide a useful role 2 in assessing the extent and usefulness of defense-in-depth.
3 CHAIRMAN JACKSON: Is there a difference between
- 4. the staff's perspective and ACRS perspective? They speak of 5 maintaining the defense-in-depth philosophy.
6 MR. KING: I caught that on Friday. No. What 7 Dr. Apostolakis has said was, gee, I thought the principle 8 was going to say maintain the defense-in-depth philosophy.
9 The explanation of the principle says that, but we have '
t 10 tried to keep the statement of the principle itself short, 11 and in the explanation you will find the word " philosophy" 12 in there several times. So I don't think there is a 13 difference. ,
14 CHAIRMAN JACKSON: Okay.
15 MR. KING: Safety margins have also been a.
16 traditional part of our safety analysis. Safety margins can ,
17 be in terms of conservative methods, conservative acceptance 18 criteria, use of codes and standards, and so forth.
19 We think it's important to maintain safety 20 margins, although we-believe that in this process of using 21 risk insights it's reasonable to take a look at-the extent 22 of the safety margin: Is it above and beyond what is needed?
! 23 Is it' focusing on an item that really has some risk 24 . significance? Again, we believe risk can provide some 25 useful insights into adjusting' safety margins to focus-in on
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36 1 the right things. .
2 COMMISSIONER DIAZ: I hope that we are narrowing 3 down what is sufficient means.
4 COMMISSIONER ROGERS: That was exactly the same 5 question I was going to ask. Provide you a way of defining 1
6 sufficient.
7 MR. KING: What we say in the guide, in FSAR 8 analysis, for example, there are criteria that have to be 9~ met. Part 100 dose guidelines, for example. We are not 10 proposing that you throw those away. Maybe a plant that 11 . meets them with lots of margin could now meet them with a 11 2 little less margin. If it would allow some relaxation on 13 valve timing or something that would improve the reliability 4
14 'an operability of the-valve, clearly that kind of thing is 15 what we had in mind.
16 .The fourth item is where we bring in the risk 17 insights. We are going to talk more about the proposed 18 metrics and guidelines that go along with that, but the idea 19 is to use the safety goals to try and define what level of l 20 risk we-believe is acceptable for.the plants. l 21 Finally, the fifth item emphasizes the usefulness
. 22- and importance of performance-based implementation and 23 monitoring strategies to assess whether the analysis and 24- assumptions are really coming out as you would hope they 25- would and there aren't.any surprises.
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37 ,
l
. 1 CHAIRMAN JACKSON: How do you get at the 2 cumulative effect of changes?
i 3 MR. KING: We would expect licensees that come in i 4 and propose a change and it's approved, tha' *r.au would now 5 be factored back into their baseline PRA. So <.C chey come 6 in again, their core damage frequency, their cro Ainment 7 performance reflects the fact that they have made this 8 previous change. They keep track of these things, i l 9 CHAIRMAN JACKSON: So they will have had to have l
10 continually updated the PRA in order to get you to consider l :
. 11 the next proposed change based on this? '
12 MR. KING: Basically, yes. >
13 MR. THADANI: Yes. The guidance document says
- t 14 that when they come in with the submittal, that submittal l
j 15 should reflect design and operation of the plant, and if it i
16 .has undergone a change, they have to make sure that the j
! 17 'analysic is now consistent with whatever the design and I i
18 operation track records are.
19 CHAIRMAN JACKSON: That's interesting. I have 20 visited some plants. Admittedly what they may have in the 1
21 -plant may be different than what is in the resident's 22 office. What you have in the resident offices many times
! 23 may be five or six years old in terms of the data on the PRA
! 24 that they have sitting in the offices. So it intersects t
25 with what you are talking about.
l
- i 4
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38 1 MR. THADANI: Yes. In fact I am sure you are
- 2 correct. In many cases some of the studies are old and they 3 don't-really reflect plant design and operation today, and 4 if they want to utilize these techniques, they have to make 5 .sure that they update that stud / so that it is in fact I
6 consistent with what is out there today. Otherwise we would )
7 just not know where we are.
8 CHAIRMAN JACKSON: What does it mean, that there 9 has to be some relevant PRA submittal or update of the PRA 10 submitted?
11 MR. THADANI: Every time a licensee comes in and 12 reriests a change to the licensing basis,.for that 13 application they would have to show that the analyses in {
14 fact do reflect the plant. That has to be done.
15 CHAIRMAN JACKSON: Mr. Holahan, you were going.to ;
16 make a comment? !
17 .MR. HOLAHAN: I was just going to mention that I ;
18 think the staff has a previous commitment to the Commission I 19 to keep a database of cumulative changes made in this ,
20 context.
21 CHAIRMAN JACKSON: Are there current plans that 22 exceed the Commission's safety goals today?
i 23 MR. KING: You~are poing to hear more about this 24 tomorrow.
25 CHAIRMAN JACKSON: The answer is yes, right?
i I
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' . 1 MR. KING: I don't know if the answer is yes or ;
i 2 not.
The answer is maybe.
- 3 MR. THADANI
- Maybe. ,
' i 4 MR. KING: The answer is maybe.
f 5 MR. THADANI: But we will be discussing it further f
y 6 tomorrow. ,
1 j 7 CHAIRMAN JACKSON: You are going to be doing an ;
j 8 awful lot tomorrow, and the day after tomorrow. You know I 9 will come back on this. '
i
- 10 MR. KING
- If I could have slide 11.
~
11 [ Slide.]
i 12 MR. KING: Slide 11 provides some additional 3 E 1 .- information. We recognize that in the five fundamental t ,
1 14 safety principles there are rather important things that !
16 needed to be factored into the guidance. We have put *
- 16 another section in the reg guide that we call expectations.
i 17 Basically it's some more general guidance on implementation,
{ 18 The key items from that guidance are shown on this i i
- 19 slide. Just a few words about those,
- 20 The licensee can do PRA and he may find out that 21 there are things that need to have some safety improvements 22 made and not just burden reduction. So we would expect an 4
]- 23' integrated' assessment by the licensees of the safety impacts 1
24 of their analyses and expect not just burden reductions to
{ 25 be proposed, but.-if warranted, some safety improvements ,
i
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~ .
. t 40 i
~1 made as well. -
- 2. Because these are plant-specific changes, it's !
3 very important that the analyses reflect the as-built, 4 as-operated plant.using plant-specific data. We express l
5 that expectation in the reg guide as well.
i 6 The quality of the analyses in terms of is it 7 appropriate for the nature and scope of the proposed change, i 8 are the appropriate models being used,' appropriate data ;
i 9' being used?
10 There is some guidance in-there on~that as well as !
i 11 the traditional quality assurance type activities: Are
. 12 qualified people doing the analysis? Are records being !
i 13 kept? Is there independent verification and checks on the !
14 analysis? That kind of thing. So there is guidance'that ji 15- covers that as well in the regulatory guide.
16 We have defined the risk metrics of core damage t
17 frequency and-large early release frequency. I will talk 1 18 more'about those. Basically they are intended to cover both 19 accident prevention.and mitigation in terms of looking at 20 the risk impacts of the proposed change.
21 Then consideration of uncertainties is very 22 important. He have a fairly long section on uncertainties 23 in the_ general reg guide. It is written not as a 24 prescriptive cook book type guidance, but it really will 25 require some thinking to apply.
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i 41
. 1 It talks about where does the uncertainty come 2 from, what are ways to assess it in terms of qualitative 3 factors. It does express the intent to start off using mean 4 values, but then you need to take a look at what the 5 sensitivity analyses tell you, what is in scope, what is out 6 of scope, and make some judgments on how you treat 7 uncertainty and how does it affect your decision. i 8 CHAIRMAN JACKSON: Is the guidance clear enough? {
9 Is everyone who uses this guidance to review licensee 10 submittals going to need to go through a training program to 11 be able to know enough to give meaning to all of these 12 guidelines? l l
13 MR. HOLAHAN: Yes, and we have some training 14 plans. The other thing I would say is I'm not sure there is !
15 any individual who is going review these sort of complicated 16 issues.
17 CHAIRMAN JACKSON: You are going to do it as a 18 team approach.
19 MR. HOLAHAN: I think we are still thinking that a 20 team approach is probably most appropriate.
21 MR. THADANI: I think it is important that we 22 maintain that concept of team particularly for what I would ;
23 call the more difficult and challenging submittals. We want 24 to be sure that the right level of attention is given 25 through a team process, i
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42.
1 CHAIRMAN JACKSON: So you will pull the teams
- 2 together as appropriate for the particular review on hand?
3 MR. TRADANI: Yes.
4 MR. KING: This is an area we did highlight in the 5 Federal Register notice for feedback and we do intend to 6 continue some work on looking at the treatment of 7 uncertainties and possibly enhance what we have in the 8 regulatory guide.
9 CHAIRMAN JACKSON: That is an important area.
10 Commissioner McGaffigan.
11 COMMISSIONER McGAFFIGAN: I would like to ask a 12 . question that follows up on a question I asked ACRS last !
13 week. Are we essentially saying in so many words that in -
14 order to take advantage of this approach you are going to 15 r.eed a living PRA, and at what level, at level 2 or level 3?
16 CHAIRMAN JACKSON: Or scope level 1.
17 COMMISSIONER McGAFFIGAN: What sort of 18 documentation is really going to be required to work in this 19- area, and is it a very small number of licensees, the South 20 Texases, the Palo Verdes, who are going to be able to go 21 down this path?
22 MR. THADANI: I think it's going to be application l
23 driven. If the applications are very broad scope, covering 24 much of the plant, then clearly one~would have to have a 25 robust risk assessment with the right scope.
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1 1 On the other hand, you can get into some simpler '
2 applications where one could in fact rely on a risk 3 assessment which doesn't necessarily have a very broad scope 4 of information in it.
5 I would expect that licensees who have conducted 6 IPEs, essentially all of them can use some parts of it to 7 some level in addressing some issues. I don't know the 8 numbers, but probably a good number of them, if they want to 9 go to a very broad-based application, in-service testing or 10 --
11 CRAIRMAN JACKSON: In fact, what I was going to l 12 suggest, if you take the pilots that you are talking about 13 bringing to some closure, the tech specs, the graded QA, and 14 ISI, IST, in-service inspection, in-service testing, how
! 15 roughly would the IPE submittals that we have fall out l 16 relative to the criteria in terms of the potential for their l
17 use in each of these areas? You can pick one or two, i
18 MR. THADANI: I think with some small changes most 19 of the licensees should be able to utilize these studies for 20 changes to technical specifications. Again, it depends on 21 range and s ope of those changes. That is one end, so to !
22 speak. Yet, in some cases, depending on the scope of 23 technical specifications, we would want to make sure-that
- 24 the analysis is very robust. So it would depend on what i
25 pieces they pick.
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( 1 Let's use in-service inspection as an example. -
2 One can use these studies in a very limited way for ,
3 in-service inspection, because by and large the risk ;
i 4 assessments make assumptions about frequency of small breaks l
5 and large breaks. They generally do not really discriminate l l 6 which sections, which pipes, et cetera, may be more -
l 7 susceptible, which ones may be less susceptible, and thus t i
8 where should one's inspection focus be, because there is a !
9 lot of dose commitment involved as well through these i 10 inspections.
11 That means a new methodology has to be applied to
- 12 be able to discriminate among these pipes, so to speak, I 13 various categories of pipes, and that methodology has not i'
14 been used. I may be wrong, but I don't think that has been 15 done in probably any of the PRAs. I hope I am right on that l 16 one. l 1
17 Westinghouse owners group and ASME are now 18 developing that methodology and the staff has been working
<19 with them, so that pretty much on a real time basis we know 20 what is going on within the industry.
21 I might also note that, based on my understanding, 22 .the monetary value is probably highest in areas of l
23 in-service inspection and graded quality assurance. !
24 Technical specifications could lead to substantial monetary l 25 savings-. We have some examples in South Texas that I
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45 4 1 indicate, depending on the scope, one could end up having a 2 fair amount of savings.
3 In-service testing of the pilots that we have been 4 talking about, if I were to rank them, are probably the 5 lowest dollar return, monetary return.
6 On the other hand, this approach we are on has a 7 different type of value. As we go to in-service testing, we 8 are not only talking about frequency of testing, but we are 9 also looking at the scope of testing. The two together are 10 important, because it could be that the testing required 11 today may not cover some of the more important failure 12 modes, which means the scope of testing has to be revised to 13 make sure that those important failure modes are covered 14 through testing.
15 In the end this approach may end up leading to-16 improved safety even if the frequency goes down, because 17 it's more focused and it's focused o the right failure 18 modes.
19 CHAIRMAN JACKSON: Mr. Holahan had a comment.
20 MR. HOLAHAN: I would like to add something to it.
21 This is a very important issue. I know it has gotten a lot 22 of attention between the staff and the industry recently. I 23 would say with the exception of those PRAs which the staff 24 sort of sent back on the IPE program, saying they needed 25 more work even to address the vulnerability issues, I think ANN RILEY & ASSOCIATES, LTD.
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- 1. alllof.the PRAs that have been developed can be used to a .
2 certain extent.
3 If you remember back to the framework document 4 that the staff developed as a prelude to these guidance 5 documents, we talked about there being categories, as Mr. '
6 Thadani mentioned, of some of the simpler to more complex ,
7 range of issues. I think there are numerous day-to-day type 8 issues-that licensees can use their existing PRAs for. For ,
9 prioritizing their own work, for example. I think virtually 10 all the PRAs help and give-licensees good insights for 11 making those kind of decisions.
12 I think all of the pilot activities we are ;
13 envisioning now can be addressed with the existing PRAs to a 14 certain extent. I think even those which have limitations !
15 don't mean that they couldn't be used at all. I think the 16 guidance documents will allow the industry to understand and .
17 'the staff to understand some of those limitations so that 18 some benefit,-some improvements could be made even with 19 limited PRA.
t 20 I think that is one of the reasons that we wrote 21 what I think is a rather flexible document, that invites a 22 range of qualitative insights to very detailed quantitative 23 analysis and didn't provide just a cook book that says, if 24 you do it this way, you pass, and if you don't do it this L
25 way, you fail.
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- 1 CHAIRMAN JACKSON: I think Commissioner Dicus has 2 a comment.
3 MR. HOLAHAN: Can I just follow up on one thing we 4 didn't mention, on Commissioner McGaffigan's issue?
5 CHAIRMAN JACKSON: Fine.
6 MR. HOLAHAN: You asked if a living, continuous 7 PRA was necessary. I don't think it's implied by this 8 process. I think the word that Chairman Jackson used was 9 " continual" updating is more appropriate in the sense that 10 it is updated when it's used for a license amendment and not 11 necessarily continuously in between. So it's sort of a once 12 in a while update to be appropriate to the decision that is 13 being made.
14 COMMISSIONER McGAFFIGAN: It depends what the 15 words "as-built" and "as-operated" mean. If it's continual 16 and if they are coming in for repeated amendments, then it's 17 going to be pretty living. If they make a change every five 18 years, maybe it's only every five years they have to. Is 19 that right?
20 MR. HOLAHAN: Yes, I think that's right.
21 COMMISSIONER DICUS: My question comes out of a 22 couple of things that I think you commented on. I pick up 23 on or hear, and I think this is what you were at least in 24 part addressing, that the nuclear power plant industry at l
25 some point bought into the whole concept of PRA, and ANN RILEY & ASSOCIATES, LTD. 1 Court Reporters 1250 I Street, N.W., Suite 300 l Washington, D.C. 20005 !
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48 1 obviously has put resources into this, as we have as well. )
2 I am picking up and hearing now that the industry may be j 3 less enchanted with PRA than previously, in part because-4 benefits that they perceived would be available at some 5- point in time are not being realized.
i 6 Is that accurate, and if.it is, what might we do 7 about it? Because it's labor-intensive to us as well. If 8 it's not really accurate or not as close to what is really 9 the case as it should be, then where is this perception 10 coming from? I think your views on that would be useful to 11 me.
- 12. MR. JORDAN: Certainly it's a perception and we 13 have all heard it at various meetings and in discussions 14 with industry people. I think this guidance is now an 15 articulation by the staff of how the industry and the NRC 16 may use PRA in a wise fashion for beneficial purposes for 17 both industry and the regulator. I believe this is the 18 right answer, and now it's a matter of getting the industry 19 comments on this set of material and seeing how this now 20 fits their perception.
21 MR. HOLAHAN: It's clear that there is industry 22 frustration at the timing. I hope they are not disenchanted 23 with PRA as a tool. They might be somewhat disenchanted 24 with the staff, at the pace of our progress, but I think 25 that is easier to deal with than reinvigorating their ANN RILEY & ASSOCIATES, LTD.
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49 l
. 1 interest in the technology. )
l 2 Hopefully the pilot applications that we are going l 3 to try to get out in this month and next month and putting 4 the guidance document on the street may bring them back.
5 I think this is the right thing to do, and I think 6 the industry will be receptive when they see that the staff 7 is receptive.
8 CHAIRMAN JACKSON: Can you do the tie-in for us l 9 between these documents and the pilots? Are the pilots 10 being evaluated relative to the criteria in the documents so 11 that in fact in interacting with the industry on the pilots 12 you are de facto getting feedback on these guidance 13 documents?
14 MR. THADANI: Yes. That is in fact what we are 15 doing. I would again add the industry has been very anxious 16 to get the documents out in the public arena for further 17 discussion. They have been concerned with the time that the 18 staff has taken in getting these documents completed. !
19 As I noted earlier, there are some products we can 20 get out now. We do not have to wait much longer. For 21 example, technical specifications change. For example, if 22 we get the graded QA work completed on South Texas by the 23 end of June, the understanding we have based on Commission 24 SRM is that we will provide that information to the l
l 25 Commission. Should there be some objections, of course we I
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50 1 will not issue these evaluation reports. Barring that 2 concern from the Commission, we would be able to issue the 3 safety evaluation reports.
4 I would like to think that that would be a good 5 signal to the industry once we get these documents out.
6 CHAIRMAN JACKSON: Let me make sure I understand.
7 Were the safety evaluation reports that either have been done or you are saying will be done or should be done by
~
8 9 July done relative to the guidance that is in the guidance 10 documents that the Commission is considering for release to 11 the public?
12 MR. THADANI: Yes. The Commission indicated to us 13 that they would not review and approve issuance of those 14 safety evaluation reports but that the Commission would like 15 to see them for information.
16 CHAIRMAN JACKSON: Right. The point I'm asking
.17 is, were the safety evaluation reports themselves done 18 referencing the guidelines in these guidance documents?
19 MR. THADANI: Yes, indeed.
20 MR. HOLAHAN: Indeed that is to a certain extent 21 what has taken more time on the pilots, because they started 22 out with a certain format and content and we have in fact 23 imposed on them the approach that we have in the guidance 24 documents here.
25 The one exception is the staff did approve the ANN RILEY & ASSOCIATES, LTD.
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49
. 1. interest in the technology.
2 Hopefully the pilot applications that we are going 3 to try to get out in this month and next month and putting 4 .the guidance document on the street may bring them back.
5 I think this is the right thing to do, and I think 6 the industry will_be receptive when they see that the staff i
7 is receptive.
8 CHAIRMAN JACKSON: Can you do the tie-in for us 9 between these documents and the pilots? Are the pilots 10 being evaluated relative to the criteria in the documents so 11 that in fact in interacting with the industry on the pilots 12 you are de facto getting feedback on these guidance 13 documents?
14 MR. THADANI: Yes. That is in fact what we are 15 doing. I would again add the~ industry has been very anxious 1
16 to get the documents out in.the public arena for further 17 discussion. They have been concerned with the time that the j l
18 staff has taken in getting these documents completed. l l
19 As I noted earlier, there are some products we can l 20 get out now. We do not have to wait much longer. For 21 example, technical specifications change. For example, if 22 we get the graded QA work completed on South Texas by the l 23 end of June, the understanding we have based on Commission 24 SRM is that we will provide that information to the 25 Commission. Should there be some objections, of course we ANN RILEY & ASSOCIATES, LTD.
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50 1 will not issue these evaluation reports. Barring that 2 concern from the Commission, we would be able to issue the 3 safety evaluation reports.
4 I would like to think that that would be a good 5 signal to the industry once we get these documents out.
6 CHAIRMAN JACKSON: Let me make sure I understand, 7 Were the safety evaluation reports that either have been 8 done or you are saying will be done or'should be done by 9 July done relative to the guidance that is in the guidance i 10 documents that the Commission is considering for release to i l
11 the public? 1 l
i 12 MR. THADANI: Yes. The Commission indicated to us 13 that they would not review and approve issuance of those l 1
14 safety evaluation reports but that the Commission would like 15 to see them for information.
16 CHAIRMAN JACKSON: Right. The point I'm asking 17 is, were the safety evaluation reports themselves done 18 referencing the guidelines in these guidance documents?
19 MR. THADANI: Yes, indeed.
20 MR. HOLAHAN: Indeed that is to a certain extent 21 what has taken more time on the pilots, because they started 22 out with a certain format and content and we have in fact 23 imposed on them the approach that we have in the guidance 24 documents here.
25 The one exception is the staff did approve the ANN RILEY & ASSOCIATES, LTD.
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1 l
51 1 boiling water reactor owners group testing program more than l
2 a year ago. I think that was done in line with our thinking l
- 3. at the time and is not quite the same scope and content as l 4 we have here.
5 CHAIRMAN JACKSON: But the others are aligned?
6 MR. HOLARAN: Yes. !
7 CHAIRMAN JACKSON: Okay.
8 MR. KING: If I could have slide 12, please.
1 9 [ Slide.]
10 MR. KING: Slide 12 and 13 show our proposed risk )
11 guidelines. Slide 12 is the risk guideline for accident 12 prevention, which we are proposing to use core damage 13 frequency as the metric, and slide 13, the risk guideline 14 for accident mitigation where we are proposing to use large 15 early release frequency.
16 Basically these risk guidelines define the 17 conditions under which changes in risk would be permitted 18 both on an absolute scale and on a relative scale. The 19 absolute scale is derived from the Commission's safety goals 20 and their subsidiary objectives, and the relative scale from 21 the regulatory analysis guidelines.
22 In effect, what we are proposing defines the terms 23 "small" and "under certain conditions" which were discussed 24 in the Commission's January 22nd SRM.
j 25 Core damage frequency. What we are proposing is l
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j 52 1 to use on the absolute scale 10 to the minus 4th'per reactor -
-2 year as the value above which further increases in risk 3 'would not be permitted. This is the same value the 4 Commission endorsed for use back in 1990 as a benchmark for
.5 accident prevention.
6 For the relative change we are proposing a delta ;
7 CDF or change in'CDF of 10 to the minus 5th per reactor 8 year. That guideline is consistent with the guideline in 9 the regulatory analysis guidelines document. It essentially 10 limits changes in risk to small steps.
11- We think from the regulatory analysis guideline 12 standpoint it doesn't make sense to allow big changes, 13 . increases in risk that would essentially be candidates for !
14- backfit. Therefore we feel using the regulatory analysis 15 guidelines value is appropriate.
16 oCHAIRMAN JACKSON: I think Commissioner Diaz wants 17 .to ask something.
18 COMMISSIONER DIAZ: A relative change or each time 19 change?
20 MR. KING: This is each time change.
21 COMMISSIONER DIAZ: Then the total cannot approach
-22 absolute.
23 MR. KING: Yes.
24 The.other reason we think limiting increases in 25 risk to small steps makes sense is it provides time for the ANN RILEY & ASSOCIATES, LTD.
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' .. 1 monitoring and feedback and corrective action process to be j 2 put in place and utilized.
j 3 MR. THADANI: Commissioner Diaz, if I may add to 4 what Tom King was'saying. The real thrust is if we allow 5 one-time changes which are in this area of 10 to the minus 4 6 to 10 to the minus 5 frequency, then if you go to regulatory l 7 analysis guidelines, that can become-a candidate for backfit 8 because that is a definition of substantial improvement in 9 safety. We are trying to be careful that we are not 10 marching in a direction and then stepping back and saying, l
11 wait a minute, we can now backfit. That is really the key '
12 point. .
l 13 CHAIRMAN JACKSON: Let me ask you a couple 14 questions. Essentially your discussion of large early ,
j- 15. release frequency parallels that of core damage _ frequency.
16- So let's talk about CDFs for the moment. Does'this mean. . ,
l 4
l 17 that plants with IPEs with core damage frequencies greater i
18 than 10 to the minus 4 need not apply for any relaxations?
l 19 MR.' KING: No. We think relaxations can accompany ,
20 risk decreases.
-21 CHAIRMAN JACKSON: I understand your point.
22 Do any of the pilots have CDFs or LERFs such that 23 " increased management attention" is required?
24 MR. HOLAHAN: .Oh, yes.
- 25' MR. KING: Yes.
4.
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54 1 MR. HOLAHAN: Most, I would say. -
4 2 CHAIRMAN JACKSON: Do you anticipate that for 3 those specific applications the guidance documents would 4 incorporate what that increased management attention 5 process would be?
6 MR. HOLAHAN: The guidance documents treat the 7 topics in general, and they are listed in the guidance 8 document. It's not exactly a cook book. It's guidance as 9 to what issues ought to be looked at more deeply.
10 CHAIRMAN JACKSON: These are mean values that are 11 compared to the core damage frequency and to the LERF, 12 right?
13 MR. KING: Yes, mean values.
14 CHAIRMAN JACKSON: Let me go through here. This 15 is where a little bit of knowledge makes you dangerous, or 16 dangerous to yourself if nothing else.
17 As I understand the PRA process, mean values can 18 only be calculated if distributions are propagated through 19 the fault trees. That's the way I learned it.
20 MR. HOLAHAN: Yes.
21 CHAIRMAN JACKSON: So how many of the IPEs l l
22 actually propagated distributions through the fault trees? i l
23 MR. KING: Let me ask Mary Drouin, who you will be 24 hearing from tomorrow. Maybe she can answer that one.
1 25 MS. DROUIN: What I first say is that they were '
l l
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. 1 not asked in the generic letter to do a formal uncertainty
[ 2 analysis as part of their IPE. We did see that some of the j 3 licensees did do it. My suspicion is that most of the j 4 licensees probably did it but did not report it.
5 CHAIRMAN JACKSON: The real question is not so 6 much whether in the IPEs as done in response to the generic 7 letter were the distributions propagated through the fault 8 trees, but that in making assessments relative to these risk j 9 guidelines will we be expecting that in those PRAs that the 3
, 10 ' distributions are propagated through the fault trees in ;
4 j 11 order to arrive at these judgments?
12 MR. THADANI: For those applications, yes.
{
13 CHAIRMAN JACKSON: That's what I'm saying.
14 MR. THADANI: For those applications, yes. They 1
15 have to come back with mean values.
4 16 CHAIRMAN JACKSON: The appropriate mean values.
, 17 MR. THADANI: Yes.
18 MR. HOLAHAN: However, we hrt said that there may 19 be some simple cases where the changes are so small and the ,
20 risk is relatively low.
21 CHAIRMAN JACKSON: I'm talking about when you are 22 talking about satisfying things according to what you have 23 on these two sheets here, that you actually have to do the 24 full distribution propogation. '
25 MR. THADANI: Yes, for those.
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56 1 MR. HOLAHAN: We did say there may be some cases -
2 in which even comparison with these numbers, if they are far 3 enough away, if they are more than a factor of 10 away from 4 these numbers, that point estimates could be --
5 CHAIRMAN JACKSON: But you have already specified 6 by virtue of what you are saying what the delta CDF is and 7 the delta LERF is. You have already said that, right, that 8 that is the factor of 10?
9 MR. HOLAHAN. Once you are within the factor of 10 10, yes.
11 CHAIRNAN JACKSON: That's all I'm really asking.
12 MR. HOLAHAN: Yes, that's true.
13 CHAIRMAN JACKSON: In a certain sense that is what 14 undergirds all of this. These are probabilistic quantities.
15 So we can never have 100 percent certainty.
16 MR. THADANI: That's right.
17 CHAIRMAN JACKSON: Shou.d we be saying or are you 18 saying that these criteria should be met with some kind of 19 assurance or confidence level?
20 MR. KING: There are some general words in the 21 uncertainty section of the reg guide that talk about 22 confidence level. I 23 CHAIRMAN JACKSON: But you haven't really fleshed 1
24 that out? l 25 MR. KING: We did not specify a confidence level.
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57
.~ 1 You will see a comment in the Federal Register notice. We i
2 are soliciting comment on confidence level, what are
.3 people's views cn1 the confidence' level that these. things 4' should be met at.
5 CHAIRMAN JACKSON: We talked about it. coming back i
6 as a policy issue. !
1 7 MR. THADANI: Yes. That's what I was going to l 8- say.
~
That would be a policy issue.
9 CHAIRMAN JACKSON: The.ACRS has proposed that the j 10 lower tier risk acceptance criteria, the CDFs and the LERFs 11 again, be derived directly from the prompt fatality QHOs and j 4
.12 be of such value as to bound all the current sites. Does 13 'the. staff have a view on this? .
14 MR. KING: Where we derived our LERF value was l 15 from starting with the early fatality QHO and using L 16 NUREG-1150 analysis and looking at if you were.just to meet i 17- .the early fatality QHO, which is the most. controlling QHO, I 18 what kind of LERF would you need to.have. The 1150 plants 19 were below the QHO; they met'it with some margin. We looked 20 at what would it take for them to just meet it.
1 21 There was some adjustment and conservatism for the !
2'2 fact that.1150 didn't cover low power and shutdown, for I 23 example, and not all the plants included external events, 24 .but providing some adjustment factors for that, we arrived 25 at the 10 to the minus 5th.
l l
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58 1- We are looking at the ACRS proposal, which I think
- 2 maybe goes into a little more detail in that. Certainly we ;
3 may want to adjust our number, but at this point we think we 4 are pretty close to ACRS in terms of the numbers they 5 proposed using their methods. So I think it's a good, 6 reasonable ballpark number to work with.
7 CHAIRMAN JACKSON: I think it's important that you 8 try to work to resolve this during this period that you are 9 also resolving other public comments.
10 MR. THADANI: If I may make a comment. The 11 Commission in an SRM -- I think it was in June of 1990 -- r 12 CHAIRMAN JACKSON: That was before our time.
13 MR. THADANI: -- recognized that the frequency of 14 large early~ release of 10 to the minus 5 was probably more 15 appropriately representative of meeting the quantitative
'16 health objective, the prompt fatality criterion.
17 The Commission also recognized that there are 18 uncertainties in these calculations, recognized that the l 19 selection of 10 to the minus 6 guideline value for 20 -implementation purposes was a reasonable way to go, with ,
l 21 full recognition that there was probably some conservatism 1 22 in that guideline and that that level of conservatism was l 23 appropriate.
1 24 What we are talking about now is that -- I think 25 that's the large early release frequency discussion that Tom ANN RILEY & ASSOCIATES, LTD.
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59 l
1 is going to go through -- we would like to hold at 10 to the 2 minus 6 also. However, there may be some cases where the i
3 frequency could exceed 10 to the minus 6, and then what kind 4 of attention would we give to that element.
5 I just wanted to make sure and bring up the issue ;
6 of the 1990 SRM.
7 CHAIRMAN JACKSON: Let me ask you one last 8 question. When full scope PRAs are not available, are you 9 going to use something like bounding analyses to address 10 things like external events, fire, earthquakes, and 11 shutdown?
12 MR. KING: The approach we have taken now is if 13 the proposed change, for example, doesn't affect low power 14 and shutdown, then just a full power analysis would be fine, 15 but if it does, the licensee is going to have to show either 16 quantitatively or with some good qualitative arguments how
- 17 the risk is impacted in those conditions that aren't 18 explicitly modeled in the PRA.
19 The other thing we have done is provide in the 20 general reg guide an appendix thac if someone has just a 21 level 1 PRA there is a way to estimate the level 2 results 22 and estimate a LERF based upon the level 1 analysis and the 23 previous work we have done, particularly with the 1150 and l 24 Lasalle PRAs.
l l 25 CHAIRMAN JACKSON: So you would use the level 1 ANN RILEY & ASSOCIATES, LTD.
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60 1 analysis with some kind of a bounding analysis to get some -
2 sense of the effect of external events on the overall risk?
3 MR. KING: This is for internal events only.
4 Where just the level 1 analysis has been done and someone 5 wants to estimate their LERF, there is a method proposed in 6 the appendix to the general reg guide that allows them to do 7 that.
8 CHAIRMAN JACKSON: I guess I am really asking you 9 is, how do you intend to take account of external events 10 within this context?
11 MR. HOLARAN: What I would add is that the first 12 thing is we would like to have licensees submit an analysis.
13 That is always the easiest. I think if they wish to put a 14 bounding analysis, that is certainly acceptable to the 15 staff. In the absence of those, we will ask the licensees 16 to make a judgment about how that would affect their 17 proposal.
18 We haven't taken a position that it necessarily 19 has to be bouncing. In this arena we would like to keep the 20 judgments closer to best estimate. Otherwise there is some 21 biasing about what is important and what's not.
22 I think we will press the licensees to address 23 full spectrum of issues and the staff also in a judgmental 24 way.when there is lack of analysis.
25 CHAIRMAN JACKSON: That's why you need a team.
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61 1 MR. HOLAHAN: I think it helps.
2- MR. THADANI: Let me also emphasize that that is a 3 very important issue, because if one were to truly go with 4 bounding assessment of assumptions, then clearly external 5 events are going to be the key. As you well know, in the 6 hazard functions there is large uncertainty, and if one goes 7 for bounding values, then those will be controlling.
8 . CHAIRMAN JACKSON: And they have to be very 9 conservative.
10 -MR. THADANI: Yes, very conservative.
11 CHAIRMAN JACKSON: Commissioner McGaffigan.
12' COMMISSIONER McGAFFIGAN: Again I am going to 13 return to questions I asked ACRS last week. I'm looking at 14 a paper ACRS gave us about shutdown operations that you are 15 familiar with. If you look at a BWR with a. core damage 16 frequency of 4.1 times 10 to the minus 6, how much of that 17 number should I believe? Is it 4.1 times 10 to the minus 6,.
18 somewhere between 4.1 times 10 to the minus 10? Is it a 19 factor of 10 or a factor of 100?
20 MR. THADANI: I will give you just a personal 21 view. Every time I see numbers like 4.1-times 10 to the 22 minus 6 my immediate conclusion is that there is much 23 greater perceived precision than there really is in these 24 -analyses and calculations, particularly when you go to 25 shutdown conditions where the majority of the contribution ANN RILEY & ASSOCIATES, LTD.
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62 1 is coming from human errors. -
2 CHAIRMAN JACKSON: You have to be careful, though, 3 because if you are talking about starting with a core damago
.4 frequency'of one 10 to the minus 4 and you talk about delta 5 core damage frequency that is 10.to the minus 5, you are 6 talking about going from 1.0, 10 to the minus 4, to 1.1, 10 7 to the minus 4, right? .
8 MR. TRADANI: Absolutely, yes. I think we can
.9 come back to this issue for confidence in delta.
10 COMMISSIONER McGAFFIGAN: I'm going to get to 11 that. As I told him last week, it's a matter of arithmetic 12 why you have greater confidence in deltas than you do in the 13 total, and I understand that, but that gets to the delta 14 question. If I believe that.this plant, whatever it is, a 15 Mark 3 BWR, is at 4.1 times 10 to the minus 6, and now I'say 16 in the risk guidelines you can make changes of up to 10 to 17 the minus 5 in core damage frequency, then I'm making a 18 factor of a 2-1/2 change in that, if I believe any of this.
19 Is that a small change in risk? When you guys chose 10 to 20 the minus 5 as the delta, did you think about 10 to the 21 minus 6 as an alternative?
22 MR. THADANI: Yes. In fact, what we are saying is 23 .by and large many of the changes actually are going to be 24 below delta of 10 to the minus 6. If you look at general 25 license amendments, most of them are not that significant.
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63 1 We are saying 10 to the minus 6 delta is a fairly small 2 change.
3 CHAIRMAN JACKSON: I think he's saying something 4 else. If you start low, are you going to allow a factor of 5 10 to 100 increase?
6 MR. THADANI: Yes. I'm saying now you go up to 10 7 to the minus 5, which is an appreciable change. We are 8 saying we are going to have to look at a number of factors 9 before we say, yes, indeed, go ahead.
10 One issue we said we would take a very hard look 11 at is going to be the issue of uncertainties. The other 12 issue that we are going to take a very hard look at is, does 13 it really potentially bypass two barriers? During shutdown 14 condition, if it's a boiler, very likely the containment is 15 open. So we have got to be very careful, because now we are 16 are talking about delta CDF as well as potential for perhaps 17 a significant release.
18 So one has to integrate all those issues as one 19 goes to deltas, which are now appreciable. Ten to the minus 20 5 delta CDF, in my view at least, for a change through an 21 amendment process is a very significant change.
22 COMMISSIONER McGAFFIGAN: That is my impression as i
23 well. Why not a number 2 times to the minus 6 rather than 24 10 to the minus? You are saying 10 to the minus 5 is where 25 there will be more analysis.
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1 MR. KING- Actually it starts at 10 to the minus -
3 2 6. We are now withic a factor of 10 of the value shown on l l a the viewgraphs. You go into the more analysis tension 4 region. I think that region is intended to address the i
4 5 concern you are expressing.
, 6 MR. HOLAHAN: There has been a lot of discussion :
i 7 on this issue. In the industry guidance to themselves as to 8 how to use the PSA applications guide they chose to give l
9 their guidance in terms of percentage of the current value. ,
10 In other words, if you were at 10 to the minus 6, 10 percent l 11 of 10 to the minus 6, not 10 percent'of the safety goal 12 subsidiary objective. f 13 So we had considerable discussions among the staff ;
14 and with the ACRS as to should changes be measured with 15 respect to where you think the plant is or with respect to 16 your safety guidance values. We came around to saying that 17 it's more important to believe your speed limits than to 18 just deal with the changes. I think that means you are ;
19 treating the 10 to the minus 4's and 5's and 6's as though 20 they matter more than in effect penalizing a plant that, is 1
21 very safe and saying it can make almost no changes.
22 MR. KING: I think we probably talked about n.ost 23 of the material on; slide 13. So let me propose to go on.
24 [ Slide.)
25 MR. KING: In slide 14, all I wanted to do there l
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'. 1 was illustrate the areas where the application specific 2 guidance supplements the general guidance. I don't intend 3 to go into those in any detail, but I did want to point out 4 that these are unique areas, that you will find discussion 5 in the application specific guidance that you' won't find in 6 the general guidance.
7 CHAIRMAN JACKSON: So all of these are part of 8 what we already have?
9 MR. KING: That is all part of the package of what 10 you have.
11 COMMISSIONER ROGERS: Before you leave that I do 12 have a concern, and that is that whether any of these really 13 represent something that's in a rule or the' equivalent of a 14 rule and therefore using a PRA analysis strictly speaking I
15 might take one out of compliance with that rule. For
-16 instance, where any ASME codes are involved and referenced '
17 by rulemaking such as test intervals or something of that 18 sort. How do you propose to deal with that? l 19 MR. THADANI: There is under 50.55 (a) an-20 alternative approach option that the Director of NRR can 21' approve. That is indeed what we indicated as one of the 22- policy issues and indicated that is the path we go on in I 23 terms of in-service testing. I believe the Commission I
24 approved that path. '
25 'You are quite correct. Otherwise it could mean ANN RILEY & ASSOCIATES, LTD.
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66 1 change the regulation. -
2 COMMISSIONER ROGERS: In every case is there some 3 disclaimer of that sort?
4 MR. THADANI: Yes.
5 MR. HOLAHAN: In fact it's our first principle, 6 that you meet the regulations or you get an exemption or we 7 have a rule change.
8 CHAIRMAN JACKSON: Therefore any of the guidance 9 that comes out of here is not going to conflict. !
10 MR. THADANI: That's correct.
11 MR. HOLAHAN: In fact it ought to contribute to 12 convergence between compliance and safety issues.
13 MR. KING: The final thing is not a viewgraph, but 14 Ashok had mentioned in the beginning that we owed you a 15 short update on the human performance and reliability 16 assessment plan that you asked for last Friday.
17 As you recall, ACRS suggested we need such a plan.
18 So did our Nuclear Safety Research Review Committee. We 19 agree. We have responded to ACRS that we plan to have such 20 a plan ready for review by the end of June.
21 That plan is going to cover human performance and 22 human reliability aspects for both reactors and materials l 23 facilities. It is going to be based on an integrated model 24 of human performance; it is going to deal with activities 25 related to events assessment, inspection, design; it's going i ANN RILEY & ASSOCIATES, LTD.
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- 1 to cover the database question; and it's going to talk about !
P 2 where do we get the data, both domestically and l; 3 internationally, both nuclear industry and applicable data l
4 from outside the nuclear industry.
5 Our schedule is to have that plan available to be i
6 given~to ACRS the end of June. We are having a subcommittee -!
7 meeting with them June 3 where we will give them a status 8 report and discuss it in viewgraph form.
J 9 We also plan to meet with ACRS later in the summer
- 10. and eventually request a letter from them. We also plan to 11 meet with the_ Nuclear Safety Research Review Committee on 12 this.
13 Ultimately we hope to have it finalized and we'll 14 provide it to the Commission by the end of September.
15 What we are not waiting for is-to move out on the 16 agency database question. We recognize that across the i 17 agency we have several databases. It probably would be more _l 18 efficient to get together and have a common database. We've 19 had a kickoff meeting among the offices to start that 20 activity, to-identify what are our data needs, what data do 21 we want to put in there, what's'the quality of the data we 22 need, and we hope to begin implementation of that by the end 23 of_ September. ,
1 24 In a very short fashion, that is what we plan to.
~25 do in that area.
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68 1 MR. THADANI: Gary. -
2 [ Slide.]
3 MR. HOLAHAN: On slide 15 there is a discussion of 4 performance monitoring. Back in the January 22, 1997, SRM S the Commission asked for a summary discussion of performance 6 monitoring in the context of both the pilot applications and
'7' the guidance documents.
{
8 The guidance documents do have sections addressing l 9 performance monitoring. It is one of the four key steps i i
10 'that Tom King mentioned. In fact it's the third step. It's !
11 covered by discussion in section 2.5 of the regulatory ;
12 guide, and there are corresponding sections'in each of the l
13 other reg guides and. standard review plans.
[
i 14 There have been discussions between the staff and' l 15 the pilot applicants on the issue of performance monitoring. {
16 Those are along the same lines as we have presented in the ,
17 guidance documents. j 18 In the staff's report and even'up until today the 19 'only document that we have really taken a final position on f 20 this issue is the CE owners group lead plant, the Arkansas '
21 tech specs. F 22 In effect this issue is still in the review 23 process for the graded QA and the IST pilot applicants. We 24 have asked them questions and we are pursuing the issue 25 consistent with the guidelines in the reg guides and the l
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69 1 SRPs.
2 CHAIRMAN JACKSON: How do the guidelines for 3 performance monitoring here compare with the guidelines 4 under the maintenance rule for performance monitoring?
5 MR. HOLAHAN: In our guidance documents and in the 6 pilot applications, the Arkansas one as an example, we say 7 that that the maintenance rule is the expected starting 8 point for the licensee in their performance monitoring 9 activities.
10 There are a few differences between what is 11 monitored under the maintenance rule and what would apply to 12 a specific application. One is that the maintenance rule 13 calls for monitoring in the context of maintenance 14 activities. So what they count, for example, is 15 maintenance-preventable failures. That may or may not be 16 sufficient for a given application. We may be interested in 17 other type of failure mechanisms.
18 In practice many licensees are keeping a broader 19 set of data even under the maintenance ru'.e than just 20 maintenance-preventable failures. As the data rule or 21 voluntary approach to reliability data moves ahead, we are 22 seeing that the industry will be developing a database one 23 way or another for addressing these issues.
24 The other thing that the maintenance rule differs 25 from some applications is that for low safety-significant ANN RILEY & ASSOCIATES, LTD.
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70 l I systems the monitoring in the maintenance rule is usually 2 done on a plant basis and not on a component reliability 3 basis. Since many of the applications we are talking about
~
4 are making changes, reducing requirements for the low l 5 safety-significant systems, the monitoring we are talking 6 about is making sure that those systems with reduced 7 requirements don't become significantly less reliable than 8 was expected.
9 The maintenance rule as it's currently written lo doesn't necessarily provide component or even system level 11 information. So when we come to a specific pilot, 12 performance monitoring on that application would either 13 require reliability or availability information, depending 14 upon what sort of pilot application it is.
15 Some of that might be available through the 16 maintenance rule. But we see in most cases is you probably 17 have to stretch the amount of data that is kept from the 18 maintenance rule. It's done similarly, but I think probably 19 a little more data has to be kept.
20 For example, in graded QA the concern is, with 21 less quality assurance, is it possible that the equipment is 22 becoming less reliable? So some sort of reliability data is 23 the check to see whether that's happening or not.
24 In contrast to that, under the technical 25 specification amendment in which longer outage times are ANN RILEY & ASSOCIATES LTD.
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- 1 being allowed, what we are interested in checking is seeing 2 whether those longer outage times are contributing to 3 increased inappropriately large unavailabilities. So the 4 monitoring approach is tailored to the individual issue.
t 5 If we go to slide 16, it discusses the specific 6 example of the technical specifications in ANO 2. In that 7 evaluation there is a specific section in the safety 8 evaluation report parallel to what is in the guidance 9 documents addressing performance monitoring.
10 As I mentioned, equipment availability is the 11 concern with increased allowable outage times. That is 12 written into the safety evaluation report and it's tied to 13 the maintenance rule for the specific equipment that has 14 changes.
4 15 The safety evaluation report has basically not 16 only performance monitoring, but a corrective action 17 section, in which case corrective action through the j 18 maintenance rule would look at whether the technical 19 specification is contributing to an inappropriate amount of 20 unavailability, in which case it would be addressed in the 21 context of the maintenance rule.
22 This is done on a two-year basis in looking at 23 reliability and unavailability, and if those numbers are 24 exceeding the balance or the goals t.iat licensees have 25 established, then we would either consider rewriting the ANN RILEY & ASSOCIATES, LTD.
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72 1 technical specifications to pull that back or look at what .
2 other actions ought to be taken to address that issue.
3 This is the only case in which we have actually 4 4 written when the Commission approves it, which would be an 5 approved example. I think it establishes a general format 6 that will be used in other cases, but since graded QA may be 7 the next example to come by, I think we will see emphasis on 8 equipment reliability data as opposed to availability in ;
9 that case.
10 CHAIRMAN JACKSON: Commissioner McGaffigan. ,
'll COMMISSIONER McGAFFIGAN: In the paper you sent us 12 on ANO 2's proposed change you say at some point here that 13 in approving .he proposed tech spec changes the staff is 14 relying on a commitment made by the licensee with respect to 15 utilization of a risk-informed configuration control. ,
i 16 technique to assess the risk associated with removal of l 1
17 equipment.
18 Are we essentially changing the "should" to ,
l 19 "shall" in the maintenance rule with regard to configuration i 1
20 control by having this license condition or administrative i i
21 control and tech specs put into this license?
22 I don't know how broad the configuration control i i
23 is going to be, but if they have a risk-informed 24 configuration control system, that is the "should" versus 25 "shall" issue in the maintenance rule. I ANN RILEY,& ASSOCIATES, LTD.
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1 MR. HOLAHAN: I think what it says is this 2 licensee has made a commitment to have a program.
l 3 COMMISSIONER McGAFFIGAN: Since this is a '
4 precedent, we will expect similar commitments from other
{
5 licensees as they come in, and for that category of 1 6 licensees the maintenance rule "should" has converted to a 7 "shall."
8 MR. HOLAHAN: I think it's not quite converted.
9 In terms of enforcement against the rule versus enforcement 10 against this particular license amendment, I think there are 11 a little different implications. But I think it does move 12 it into a regulatory requirement of some sort.
13 MR. THADANI: Our focus as we are conducting these 14 reviews is to make sure that prior to allowing relaxation 15 that we have taken an integral look at safety implications 16 of the change. We believe configuration control is very 17 important because of the way risk analyses are traditionally 18 done. We have indicated as a condition of approval that 19 that control has to be maintained if this relaxation is to 20 be granted.
21 You are exactly right. I have had calls from the 22 industry, very unhappy with the staff at taking that 23 approach, and why is this not covered under Part A3 of the 24 maintenance rule, which industry, as I was told, considers 25 is a requirement.
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74 1 I know you have asked us to take a look to see if -
{ ,
2 we should revise Part A3 of the rule, to change "should" to 3 "shall," and I hope we will come back to you very quickly j 4 with a recommendation. Quite frankly, the interaction that
- 5 I have had with NEI, they have indicated to me that they 6 would support changing Part A3 of the rule from "should" to 7 "shall" if that resolves this issue.
8 CHAIRMAN JACKSON: Do you want to vote it tnis 9 afternoon? i l
10 COMMISSIONER McGAFFIGAN: I think you may have at l 11 least one Commissioner who is receptive. Having seen this
-12 paper, it struck me in a machiavellian sense that one reason 13 you answered the question in a more ambiguous way when first
,14 asked is that you have these other methods to catch ;
15 licensees' attention and you end up converting the "should" l 16 to "shall" anyway, so we might as well just do it up front.
17 MR. THADANI: We think it's an important safety 18 issue and it ought to have some enforcement capability i 19- behind it.
20 CHAIRMAN JACKSON: And this is how you are doing 21 it for now until you come back to us with a specific 22 recommendation fast.
23 MR. THADANI: Yes.
24 CHAIRMAN JACKSON: Okay..
25 MR. HOLAHAN: The last thing I would like to cover ANN RILEY & ASSOCIATES, LTD.
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75
- 1 on performance monitoring is to go back to Chairman 2 Jackson's question about what does it take to be fully risk 3 based as opposed to being what we have called risk-informed 4 with performance elements built into it. I think there are 5 really two differences between what we have done here and 6 what would be a fully risk-based approach.
7 The first is, frankly I'm not sure what a 8 risk-based approach is. If you ask 100 people, you might 9 get 100 different answers. So I think there is some 10 development work to be done. The staff has an assignment to 11 get back later this year to address that issue more fully.
12 But there is another issue involved in it, and 13 that is we are making license amendment in the context of 14 the existing regulatory framework. To be fully performance 15 based, I think you would have to break out of part of the 16 approach. We are still using Appendix B and the 17 programmatic elements of that; we are still using technical 18 specifications; we are still using a staff review and i
19 approval process; and I think all of those things might be j l
20 changed to some extent in a fully performance-based program.
21 Within the context of these sort of measured 22 steps, as Dr. Ross has mentioned, I don't think we can 23 become fully performance based without changing some of the i
24 other paradigms.
25 The last thing I would like to cover is future i
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76 1 activities on slide 17. -
2 [ Slide.]
3 MR. HOLAHAN:' I think much of this has already 4 been mentioned. The staff would hope to issue the guidance 5 documents in May, based on Commission guidance, l
l 6 You will note that the package does not include an 7 ISI program. We are looking towards getting the reg guide
L l
t 9 I think Tom King already mentioned the workshop, 10 and I think Mr. Thadani did a pretty detailed job of going 11 through the status of the pilots.
12' One thing that I would mention. On the slide 13 where it says graded QA, 12/97, that really applies to the 14 three pilots, South Texas, Palo Verde, and Grand Gulf. We 15 really are hoping to get the South Texas piece of that done 16 end of June, early July, something in that time frame, in a !
17' much faster time frame than December.
l 18 [ Slide.] ;
19 MR. HOLAHAN: On slide 18, this is just to remind j 20 the Commission that there are a few more IOUs from the 21 January SRM. A number of these subjects are covered in our 22 guidance documents. l 23 -In part, we will get public comment on those I
24 before we come back to the Commission. In addition, there 25 are questions for OGC about the legal implications of some ANN RILEY & ASSOCIATES, LTD.
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77 1 of these that are also needed in responding to that 2 Commission guidance.
3 I think we mentioned earlier that in fact there is l 4 some training planned for the staff on the reg guides and 5 the standard review plans to help that process along, j 6 Following the public comment period there will be
! 7 a' resolution process; there will be a series of meetings 8 with the ACRS; there will be a second round through the t 9 .CRGR; and we are still hoping to and-are committed to
~10 getting the general guidance, the tech specs, IST and graded l
11 QA completed by the end of the year.
l 12 We are hoping to get in-service inspection done by i
13 February, but I think that date is somewhat dependent upon 14 there being a~ pilot application by September. So I think 15 that date is less certain than the others. We will have a l
l 16 number of opportunities to discuss that with the Commiss' ion l
l 17 well before that date end we will know more about how that 18 is going with respect to a pilot application and progress on 19 the guidance documents.
i
! 20 I think that's all we have for our presentation.
21 CHAIRMAN JACKSON: Thank you.
22 Commissioner Rogers, any follow-on questions?
23 COMMISSIONER ROGERS: Just two. One involves 24 in-service testing. Do the failure. rates that are being 25 used for some pieces of equipment that are subject to i
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78 1 in-service testing depend on the rate of testing? -
2 MR. THADANI: I was looking around to see if the l 3 specific staff member is here or not. The intention is to 3 4 .look at that issue specifically as part of our evaluation 5 process. There are two key elements. I only touched on 6 one. The second one is the one you mentioned. If you 7 change' frequency of testing from, let's say, every month to 8 every year, you may introduce some new failure modes that 9 one may not have.
10 COMMISSIONER ROGERS: Or you may reduce the 11 failure.
12 MR. THADANI: Absolutely correct.
13 MR. KING: That is one of the items in the IST reg 14 guide that has to be.specifically addressed. That is one of 15 those supplemental items you won't find in the general reg.
.16 guide, but your specific question is in there.
t 17 COMMISSIONER ROGERS: I think for some equipment 18 it is really very important. The value of a reduced L 19 testing, if out of a PRA the conclusion comes that a testing 20 rate-could be reduced, then you may even get a double i 21 benefit.there. Not.only an economic benefit. You may 22 actually a real safety benefit from that.
23' MR. HOLAHAN: And I think these guidance documents 24 provide a road map for the licensees to take those issues l
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4 79 1 receptive to change.
l 2 COMMISSIONER ROGERS: The other question involves
.3 the quality of the PRAs. We know they are of uneven 4 quality, and yet the approach so far that we have heard l
5- about here is one that doesn't seem to specifically take l
6 that into account. I wondered to what extent you are 7 thinking of somehow or other imposing something that
~
8 provides a uniform standard here if one is going to apply 9 these constraints on deltas and LERFs.
10 MR. KING: We have a long-range goal to look at 11 standardization. At this point we think maybe that draft 12 NUREG-1602 is a good start toward a standard for PRA 13 quality. In fact, a couple of the items in the Federal 14 Register notice soliciting feedback has to do with the use 15 of that as a standard or any other suggestions for what 16 could be a standard.
17 You are right. At this point we haven't required 18 certain attributes or certain scope and depth of a PRA. It 19 is sort of up to the licensee to come in and justify. But 20 our long-range goal is to head in that direction.
21 MR. THADANI: There is a very strong
- 22. recommendation in the guide for independent peer review, 23 which I think is an important element in addressing quality 24 as well. It is strongly encouraged throughout the guide as 25 well as when you go to quality. assurance section that the ANN RILEY & ASSOCIATES, LTD.
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80 j 1 independent peer review can go a long way towards satisfying -
1 2 the intent behind Appendix B of quality analysis, i
, 3 COMMISSIONER ROGERS: When we started in on this 4 IPE process we didn't really think it would ever take us as 5 .far as we are today. So now we have to look at what the 6 quality is, it seems to me, if we want to use them.
7 CHAIRMAN JACKSON: Are we tracking regulatory uses 8 of IPEs?
9 MR. THADANI: I have to make sure that this is 10 correct, and-I will need help. As part of the i 11 implementation plan, every time we make use of individual 12 plan examination and regulatory decision we are supposed to 13 keep track of it. I will confirm that in fact we are doing 14 that.
15 CHAIRMAN JACKSON: Please do.
16 Commissioner Dicus.
17 COMMISSIONER DICUS: One question regarding the 18 concept of. current licensing basis and the application in 19 this program that we are in now. I don't want to go back 20 into what is current licensing basis. I recall from 21 previous briefings and meetings there has been lengthy
- 22. debate'and discussion over how you use something that is 23 undefined. In the applicable regulations it is only defined 24 in Part 54 with license renewal. We have been through that.
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'81 1 assessment and in submittals that licensees might be making 2 do you have any plans to actually use-the definition of 3 current licensing basis in Part 54 for this?
1 4 MR. THADANI: What we are saying is what is within S the scope. We are not suggesting with this that one needs 6 to compile all this information. However, if there is an i
, 7 issue that impacts those elements that are within the 8 current licensing basis, _the licensee's proposal to make 9 changes in that element has to cover both aspects,
- 1 10 deterministic and probabilistic. i J
11 We are not suggesting in this guidance that one
' i 12 needs to compile current licensing basis information. I 13 think that was the more difficult issue, who is going to 14 compile this information. The scope of the risk assessment, 15 we are not suggesting that changes as a result of.this.
16 COMMISSIONER DICUS: I think the answer to my 17 question was maybe. I'm not sure I heard yes or no, but I 18 think that point needs to be made v<ery clear, particularly 19 to licensees. ,
20 MR. HOLAHAN: In most of the applications we have 21 seen this hasn't turned out to be a problem. When you are 22 writing a general guidance document to try to cover all 23 future type applications, we needed some way of describing 24 sort of the scope of all possibilities, and current 25 licensing basis is kind of-shorthand for doing that. If you ANN RILEY & ASSOCIATES, LTD.
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- 82 l
' 1 look at the actual examples, ISI and IST and graded QA, -
j I
- 2. these are areas where the licensees understand what their l
- 3. licensing basis is and their need for a license amendment. j
! .4 COMMISSIONER DICUS: I just don't want the l
, 5 regulatory guide to begin to confuse the issue. We should ,
Y l
- 6 clarify the issue. l e
7 CHAIRMAN JACKSON: Commissioner Diaz.
ti 8 COMMISSIONER DIAZ: The main question I have 4-9; Commissioner Rogers, using seniority, already asked.
10 CHAIRMAN JACKSON: We will go in. reverse. You i 11' will move up the queue.
f 12 COMMISSIONER DIAZ: I don't have any questions. I '
1 4
l 13 -just want to say that I am very pleased that we have gotten 14 .to this point. I think it's a very, very great step, and I .
15 certainly commend you.
16 CHAIRMAN JACKSON: Commissioner McGaffigan.
17 COMMISSIONER McGAFFIGAN: On the time line on the 18 last chart, 12/97 you hope to have final reg guides out. '
19 You have a 90-day comment period. Thatswill take you into l 20 August. Do you expect there to be significant comments and 21' policy. issues that will then have to be resolved? Is that 22 . period between 8/97 and 12/97 optimistic?
-23 CHAIRMAN JACKSON: A drop dead date.
]
- 24. MR. THADANI: It's a drop dead date that we'have- {
25 been working towards. If you look at the set of' questions l
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- 1 in the Federal Register notice, they are very tough issues 2 and a number of them are really policy issues. I would ]
3 expect that we would end up having probably at least two q 4 separate meetings with the Advisory Committee on Reactor 5 Safeguards and extensive discussion with CRGR, and very 6 likely we may have to come August-September time frame to 7 the Commission to seek guidance on some of these issues.
8 Example. What confidence level one must ascribe. Is it 80 9 percent? 95 percent? -Whatever it is, we will come back to q 10 Commission.
1 11 CHAIRMAN JACKSON: You could be doing some !
12 parallel processing.
13 MR. TRADANI: Yes, and in fact we are going to be 14 doing that. But I think it is a very, very tight schedule.
15 CHAIRMAN JACKSON: It's ambitious, but at the same 16 time we have waited too long to get to this point.
17 COMMISSIONER McGAFFIGAN: I'm anxious to get to 18 the concluding point too. There will be a lot of, as we are 19 coming to call it, parallel processing going on if you are 20 actually going to get to that point. ,
21 MR. HOLAHAN: We hope that the workshop we have in 22 July will provide us early public feedback that we can start 23- working on. That should be helpful.
24 CHAIRMAN JACKSON: I'd like to thank the staff for 25 a very informative briefing. As you can tell by-how much ANN RILEY & ASSOCIATES, LTD.
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. i 84 1 time we have taken on the agency's PRA activities and as you -
2 have heard, we do commend you for the progress you have made 3 to date and for being responsive cn1 developing these 4 documents and working on the pilots.
5 I know it has been sometimes a difficult area, but 6 at the same time we encourage you to continue to improve the 7 process and to provide appropriate review mechanisms, both 8 internal and in terms of external reviews to ensure that we 9 appropriately use PRA. It is becoming an important tool in 10 support of the regulatory process. So we need to enhance 11 the process where necessary, but, as you've heard, to ensure 12 its consistent use where appropriate. I will just call out 13 one or two of those.
14 For instance, we discussed that relative to the 15 use of the reg guides and standard review plans in the 16 pilots.
17 We talked about performance monitoring in the 18 pilots compared with performance monitoring in the 19 maintenance rule.
20 We talked about the implications of all of this 21 for risk-informed configuration management in plants.
22 As you heard, relative to the definition of 23 current licensing basis as defined in Part 54 and what that 24 suggests relative to what we need to do in Part 50.
25 I want to especially commend you for your work in ANN RILEY & ASSOCIATES, LTD.
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. 1 producing these documents. I had asked you to do them 2 within a certain time frame. The schedule slipped a little 3 bit. We understand that. As Commissioner McGaffigan said, 4 it's still ambitious, but we are still aiming for 12/97. So 5 you should continue your efforts to complete in a timely 6 manner the' pilot applications of risk-informed regulation 7 and to complete these draft guidance documents, particularly 8 the ones for in-service inspection, on the time line that 9 you have mentioned.
10 You should also evaluate the proposed decision 11 criteria. You spoke to this yourself, Mr. Thadani. And the 12 rationale for assuring conformance to those criteria. You 13 need to develop additional guidance on acceptable approaches 14 for confirming the assumptions and the analyses that are 15 conducted to justify current license-basis changes. As we i 16 have discussed, this would include consideration of the role l l
17 of uncertainty.
18 We look forward to getting some recommendations in 19 the policy areas relative to the appropriate confidence or i 20 assurance levels in the use of PRA for decision-making as l
21 well as the development through the pilots of any additional 22 guidance that is needed on this increased management 23 attention process.
24 Unless my fellow Commissioners have any additional 25 comments, we are adjourned.
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86 1 [Whereupon, at 4:15 p.m., the briefing was '
2 adjourned.]
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5 6
7 8
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CERTIFICATE 4
This is to certify that the attached description of a meeting l 1
of the U.S. Nuclear Regulatory Commission entitled:
TITLE OF MEETING: BRIEFING ON PRA IMPLEMENTATION PLAN -
PUBLIC MEETING PLACE OF MEETING: Rockville, Maryland DATE OF MEETING: Tuesday, May 6, 1997 was held as herein appears, is a true and accurate record of the meeting, and that this is the original transcript thereof taken stenographically by me, thereafter reduced to l typewriting by me or under the direction of the court reporting company i n \
Transcriber: "h1 C CJ1 n - (. i!/n ('n 6 l l
Reporter: Michael Paulus l
I l
l 1
l J
, p~s.l
{ pl United States
....l Nuclear Regulatory Commission !
STATUSf' UPDATE OF l
PROBABILISTIC RISK ASSESSMENT l (PRA) IMPLEMENTATION PLAN Ashok C. Thadani Office of Nuclear Regulatory Research r
Thomas L. King Office of Nuclear Regulatory Research Gary M. Holahan Office of Nuclear Reactor Regulation i
May 6,1997
- OVERVIEW -
e Background ;
e Recent Accomislishments i
e Revisions to PRA Implementation Plan e Draft Regulatory Guidance for Public Comment e Performance Monitoring in Pilot Applications i e Future Activities I
i 4
--_-__------------__j
i BACKGROUND e October 1996 - Commission briefed on status of PRA implementation and proposed resolution of key policy issues.
e January 1997 - Status of PRA implementation updated in SECY-97-09. !
'l e January 1997 - SRM issued providing Commission
! guidance on resolution of key policy issues regarding risk-informed regulation of commercial-reactors.
e April 1997 - Status of PRA implementation updated i SECY-97-076.
1 t i
I RECENT ACCOMPLISHMENTS '
e Draft Regulatory Guides (RG) and Standard Review Plans (SRP) prepared for comment by the public.
e Staff safety evaluation report for risk-informed TS pilot
- application prepared for Commission review.
. t a Operator licensing examiner standards (NUREG-1021, Revision 8) issued which reflect PRA insights. i f
e r
r 3 !
~
l
! j RECENT ACCOMPLISHMENTS e Staff evaluation of voluntary approach to reporting l
reliability and availability data.
f e Public workshop conducted to discuss Draft.NUREG-1560 i (report on insights from IPE program) i j
4 !
I l
1 REVISIONS TO PRA IMPLEMENTATION PLAN l
e No significant changes inivork scope made to plan.
~
e Schedules for some items have been adjusted as necessary.
l 5
, _ . . - , . . . . . -. . _ _ e , _- = .- _ _ _ _- _ . . _ _ _ . - ___
Draft Regulatory Guidance e
SECY-97-077 provided Commission four draft Regulatory Guides, tlaree draft Standard Review Plan sections and a draft NUREG.
These draft documents provide guidance on an acceptable approach for making plant specific risk-informed changes to the current licensing basis (CLB) of a NPP, in the following areas:
general guidance inservice testing
' technical specifications graded quality assurance 6
Draft Regulatory Guidance e These draft documents reflect input received from the Commission on four policy issues, feedback from pilot programs, and extensive interactions with ACRS and CRGR.
- Staff desires Commission approval for issuing the documents for public comment.
I
Overall Approach
- Proposed guidance represents one acceptable method for licensees to propose changes to their CLB.
e Use of proposed guidance is voluntary on licensees; however, staff will consider risk in its review of proposed changes to the CLB.
e General guidance applies to all risk-informed applications.
Application specific guidance supplements general guidance and addresses specific topics unique to that area. i e Guidance developed consistent with Commission's PRA and safety goal policies, regulatory analysis guidelines and other guidance.
8
Elernents of Review Process -
e Define proposed change e Perform engineering enalysis:
traditional probabilistic integrated decision-making .
- Define Implementation / Monitoring Program o Document proposed change 9
General Guidance e Proposed changes are to be judged against five fundamental safety principles:
i t
- 1. meet the regulations (or propose a change / exemption)
- 2. maintain the defense-in-depth
- 3. maintain sufficient safety margins
- 4. proposed increases in risk, and their cumulative effect, ,
are small and do not cause the NRC Safety Goals to be exceeded
- 5. use performance-based implementation and monitoring strategies that provide for timely feedback and corrective action.
10 J
I l
l l
l General Guidance (Cont) e Other general guidance on implementation:
assess all safety impacts in an integrated manner analyses should reflect the as built, as operated plant (before and after the proposed change) analyses should be appropriate for the nature and scope of the proposed change analyses should be subject to quality controls core damage frequency (CDF) and large early release frequency (LERF) can be metrics for assessing risk appropriate consideration should be given to l
I uncertainty 11
__. _ _._ _ _ _ _ - _ . - - - - - - - - - - - - - - - - - - - - - - - - * ^ ^ - - - - ^ " ~ ~ ^ ~ -~ -
Risk Guidelines '
e Derived from Commission's Safety Goal Policy and subsidiary objectives.
e Core Damage Frequency (CDF):
d 10 /RY -
value above which further increases in risk would not be permitted ACDF=104 /RY -
value above which risk increases associated with individual CLB changes would not be permitted increased review when within a factor of10 of the above values 12
i Risk Guidelines l .
10-5/RY -
value above which further t l
increases in risk would not be i
permitted ALERF=10-6/RY - value above which risk increases associated with individual.CLB changes would not be permitted increased review when within a factor of 10 of the above values a
- Risk guidelines are intended for comparison with full scope PRA results; however, less than full scope PRA may be '
acceptable.
i 13 i
Application Specific Guidance e IST:
safety categorization ~
guidance applicable to changes to test intervals guidance applicable to changes to test methods
- Technical Specifications:
guidance applicable to changes to allowable outage times -
guidance applicable to changes to surveillance test intervals e Graded QA:
safety categorization QA associated with high and low safety significant SSCs 14
'd
l t
l i
l l PERFORMANCE MONITORING ,
L IN l PILOT APPLICATIONS t
l l
e Performance monitoring is one of the four key steps in l
making risk-informed changes to the current heensmg basis. '
e Process for pilot applications will follow from staff safety evaluation.
e Process for technical specification changes has been developed; process for other pilots in progress. ,
15
_ _ - - - _ _ _ _ _ _ _ _ _ _ - _ -_____--_-_-_-__----___-____--__-_-___J
PERFORMANCE MONITORING Technical Specifications e Staff safety evaluation for lead plant (Arkansas, Unit 2) documents performance iiionitoring approach for risk informed TS changes.
- Availability of equipment affected by TS change is trended over time as part of the licensee's maintenance program.
i e Performance criteria established per the Maintenance Rule may be used to evaluate trends in availability.
e If performance criteria not met:
corrective action per Maintenance Rule must be taken; consider change in TS allowed outage time.
16 I i
FUTURE ACTIVITIES
- Issue proposed regulatory guidance for comment (May 1997) , ;
e Complete draft RG and SRP for ISI and issue for comment by the public (July 1997). l
- Conduct workshop on draft RGs and SRPs(July 1997) e Complete pilot applications of risk-informed regulation Technical Specifications 5/97 Inservice Testing 6/97 Graded QA 12/97 Inservice Inspection 4/98 17
i FUTURE ACTIVITIES
- Address policy issues in January 22,1997 SRM (August 1997) role of performance lissed regulation in PRA plan plant-specific application of safety goals risk neutral vs. increases in risk e Train NRC staff on RGs and SRPs (November 1997) e Issue final RGs and SRPs .
General Guidance 12/97 .
Technical Specifications 12/97 Inservice Testing 12/97 Graded QA 12/97 Inservice Inspection 2/98 p,
II
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