ML20134J759
| ML20134J759 | |
| Person / Time | |
|---|---|
| Issue date: | 02/07/1997 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-T-2090, NUDOCS 9702120282 | |
| Download: ML20134J759 (182) | |
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Title:
Advisory Committee on Reactor Safeguards 438th Meeting I TRO4 (ACRS) j i RETURN ORIGINAL ! TO BJWHITE I 1 Docket Number: (not applicable) M(sg2E2s THANKS! J Location: Rockville, Maryland I
- h Date: Friday, February 7,1997 !
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l DI8 CLAIMER PUBLIC NOTICE BY THE UNITED STATES NUCLEAR REGULATORY COMMISSION'S ADVISORY COMMITTEE ON REACTOR SAFEGUARDS FEBRUARY 7, 1997 The contents , of this transcript of the < l proceedings of the United States Nuclear Regulatory Commission's Advisory Cominittee on Reactor Safeguards on Februsry 7, 1997, as reported herein, is a record of the discussions recorded at the meeting held on the above date. This transcript has not been reviewed, corrected and edited and it may contain inaccuracies. 1 i O NEAL R. GROSS COURT REPORTERS ANDTRANSCRIBERS 1323 RilODEISLAND AVENUE,NW (202)234-443I WASil!NGTON, D C. 20005 (202)234-4433
1 108 1 UNITED STATES OF AMERICA
,ew 2 NUCLEAR REGULATORY COMMISSION i
! 3 +++++ 4 438TH MEETING 5 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS (ACRS) l 6 +++++ ) 7 FRIDAY 8 FEBRUARY 7, 1997 9 +++++ 10 ROCKVILLE, MARYLAND 11 +++++ 12 The Advisory Committee met at the Nuclear 13 Regulatory Commission, Two White Flint North, Room T2B3, l O ! 14 11545 Rockville Pike, at 8:30 a.m., Robert L. Seale, 15 Chairman, presiding. 16 COMMITTEE MEMBERS: 17 ROBERT L. SEALE, Chairman 18 DANA A. POWERS, Vice Chairman 19 GEORGE E. APOSTOLAKIS 20 JOHN J. BARTois 21 IVAN CATTON 22 MARIO H. FONTANA 4 l l 23 THOMAS S. KRESS
- 24 DON W. MILLER 25 WILLIAM J. SHACK l NEAL R. GROSS I COURT REPORTERS AND TRANSCRIBERS
! 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
109 1 ACRS STAFF PRESENT: 1 g3 2 JOHN T. LARKINS, Executive Director N,) 3 ROXANNE SUMMERS, Technical Secretary l 4 SAM DURAISWAMY j 5 CAROL A. HARRIS , 1 l 6 RICHARD P. SAVIO l l 7 PAUL BOEHNERT 8 NOEL DUDLEY 9 MADHAT M. EL-ZEFTAWY 10 MICHAEL MARKLEY 11 AMARJIT SINGH 12 ALSO PRESENT: 13 TOM KING C\
\N') 14 GARY HOLAHAN 15 MARK CUNNINGHAM 16 WAYNE HODGES l
l 17 GARETH PARRY 18 BOB JONES 19 JOE MURPHY 20 TONY PIETRANGELO 21 JOSE IBARRA 22 JACK ROSENTHAL 23 ERNIE ROSSI 24 BILL JONES p (,) 25 HAL VRNSTEIN NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE , N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
( 110 1 A-G-E-N-D-A l l i (g 2 Acenda Item Paae i
'j 3 8) Or>enina Remarks by the ACRS Chairman 111 4 9) Risk-Informed. Performance-Based Reaulation and 113 5 Related Matters 6 9.2) Briefing by and discussions with 113 7 representatives of the NRC staff 8 10) AEOD Scent Fuel Pool Studv 204 9 10.1) Remarks by the Subcommittee Chairman 204 10 10.2) Briefing by and discussions with 205 11 representatives of the Office for 12 Analysis and Evaluation of Operaticn Data 13 p.
O 14 1 15 16 , 17 ] 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 234-4433
111 1 P-R-O-C-E-E-D-I-N-G-S gs 2 (8:34 a.m.) i {V 3 8) OPENING REMARKS BY THE ACRS CHAIRMAN 4 CHAIRMAN SEALE: Well, it looks like we're 5 mostly here, and it's the witching hour. The meeting will 6 come to order. This is the second day of the 438th 7 meeting of the Advisory Committee on Reactor Safeguards. 8 During today's meeting, the committee wi'. consider the 9 following: Risk-informed, performance-based regulation 10 and related matters; results of the study performed by 11 AEOD on the consequences of an extended loss of spent fuel 12 pool cooling; and proposed ACRS reports. 13 This meeting is being conducted in accordance (3 \'/ 14 with the provisions of the Federal Advisory Committee Act. 15 Mr. Sam Duraiswamy is the designated federal 16 official for the initial portion of this meeting. 17 We have received no written statements or 18 requests for time to make oral statements from members of 19 the public regarding today's sessions. A transcript of 20 portions of the meeting is being kept, and it is requested 21 that speakers use one of the microphones, identify 22 themselves, and speak with sufficient clarity and volume 23 so that they can readily be heard. 24 ~oday we again have a series of interviews of (_,/ 25 potential candidates for Committee membership in the area NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234 4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
112 1 of thermal hydraulics. You have a schedule along with
-~ 2 some resumes at your desk. And I'd ask you to be very V
3 careful to not let one of those sessions get by you. 4 There's also another matter that I'd like to 5 bring to your attention. There's an announcement that I 6 should have made yesterday. It's on this yellow mustard, 1 7 I guess, or somewhere in that general spectral range page. i 8 And it has to do with the appointment of Anthony J. < l 9 Galanti as Chief Information Officer. 10 You'll recall that in the recent restructuring 11 of the Commission, the position of Chief Information ! 12 Officer was established. And that officer will act, along 13 with the Executive Director for Operations and the Chief
/9 14 Financial Officer, on the Executive Council for the l 15 agency.
16 Mr. Galanti comes from the outside. He was 17 with Mobil's information systems and has done work in 18 exploration, producing, refining, and marketing on the 19 international arena. 20 Were there any other announcements or special 21 items that anyone would like to bring to anyone's 22 attention at this time? l 23 (No response.) I 24 CHAIRMAN SEALE: If not, we'll proceed with 25 the meeting. The first topic this morning is a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234 4433 WASHINGTON, D C. 20005-3701 (202) 234 4433 l
113 1 presentation from the staff on risk-informed, f-s 2 performance-based regulation and related matters. L.) I understand that we've also had a request 3 4 from the NEI people to make a short statement at the end 5 of that time. I thought we had anyway. So we'll have 6 that as well. 7 We're scheduled to go until 10:30. Tom, are 8 you it? 9 MR. KING: The gang of four. 10 CHAIRMAN SEALE: The gang of four. Okay. 11 (Slide) 12 9) RISK-INFORMED, PERFORMANCE-BASED REGULATION AND 13 RELATED MATTERS 14 9.2) BRIEFING BY AND DISCUSSIONS WITH 15 REPRESENTATIVES OF THE NRC STAFF 16 MR. KING: My name is Tom King. I'm with the 17 Office of Research. And I think you know everybody at the 18 table: Gary Holahan and Bob Jones and Mark Cunningham. 19 What we wanted to do today, at the request of 20 the YRA Subcommittee, was give a short overview of where 1 l 21 we stand on developing the regulatory guides and standard 22 review plans for risk-informed regulation. And then we 23 had also gotten some specific issues that they wanted i 24 addressed at the full Committee meeting today. ( 25 So the presentation is going to quickly NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
114 1 summarize the status, the activities that are going on, I - 2 the approach, and the changes that have been made in the l C/ 3 general reg guide and SRP since we last met and then 4 specifically address six questions that we got from the 5 Subcommittee back on January 28th. 6 (Slide) 7 MR. KING: By way of background and to refresh 8 everyone's memory, the Commission issued a policy 9 statement back in August of '95, encouraged the use of 10 risk information in all regulatory matters. And they felt 11 that by doing this, it would lead to better 12 decision-making, more effective use of NRC resources, and 13 could lead to burden reduction for licensees. O)# 14 A number of activities are underway as a 15 result of that. And they're documented in what's called a 16 PRA implementation plan, which we update quarterly. One l 17 of the major activities in that PRA implementation plan is l l 18 development of some reg guides and standard review plans ! 19 that are addressed toward providing guidance to licensees 20 and the staff and how you would make plant-specific 21 changes to a plant's current licensing basis. 22 Now, these are directed toward reactors only 23 at this point. And the idea is that by developing these i 24 reg guides and SRPs would help encourage submittals from I f^h (_) 25 licensees that utilize risk information and provide some NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS i 1323 RHODE ISLAND AVE . N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
L 115 l 1 consistency for the process by which one information has I g<m. 2 to be in the submittals as well as how the staff reviews (_), 3 those. 4 Ti- objectives of these reg guides and SRPs 5 are: to describe the overall approach, expectations, and 6 process of requesting changes to a CLB; to provide the l 7 principles and some guidance on how we would do the 1 , 8 deterministic and probablistic analysis and integrated l
\
l 9 decision making; to describe what we call a 10 performance-based implementation strategy, which we think 11 is important in this whole process; and to provide 12 guidance on what information does a licensee have to 13 submit in requesting these changes. We'll talk a little ' 14 bit more about each of these as we get into this. 15 This whole process because it's generated or 16 stems from a policy statement is voluntary on licensees. 17 Now, we would expect certainly that when the staff 18 receives applications for changes to a CLB if they utilize 19 risk information, they will get higher priority in ones 20 that come in and don't utilize risk information. But 21 clearly if it's a safety issue, it's going to get high 22 priority anyway, whether they use risk or not. But things 23 for burden reduction, we will give higher priority to l 24 these that utilize risk information. l (")/ (. 25 (slide) NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
I 116 1 MR. KING: Just to remind everyone what the 1
- 2 scope of these reg guides and SRPs that we're currently %J 3 working on includes, we've got what we call some general 1
4 guidance, which is right now contained in a Draft Guide 5 1061 and a related companion SRP. And then we've got 6 application-specific regulatory guides and some SRPs to 7 cover specific areas that are underway. 8 And we have some pilot applications in from 1 9 licensees in these areas. And those are: in-service , 1 10 testing, technical specifications, graded QA, and 11 in-service inspection, i l 12 The in-service inspection part is on a later 13 schedule than the others. And we won't be talking today /D/ i
' or over the next couple of months on in-service 14 15 inspection, but we will be covering the other areas.
16 We also developed a draft NUREG-1602. It 17 provides information on the scope and quality of PRA 18 analysis. Now, it's not a guideline. It's not a 19 standard. And it's not a requirement, but it's more an 20 example of: When we talk about a quality PRA, what do we 21 mean? 22 MEMBER APOSTOLAKIS: Tom, we haven't really 23 discussed in detail the applications, have we? I mean, 24 these are ongoing now. You're -- C (,)) 25 MR. KING: Are you talking about the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE IS' AND AVE , N W. (202) 234 4433 WASHING ~iCit D.C. 20005-3701 (202) 234-4433
117 1 application-specific reg guides? 2 MEMBER APOSTOLAKIS: Yes.
)
V No, we haven't. But, 3 MR. KING: No. l 4 remember, we have a subcommittee meeting scheduled the 5 20th and 21st. i 6 MEMBER APOSTOLAKIS: So we will do it then? 7 MR. KING: Yes. 8 MEMBER APOSTOLAKIS: And you will mell us 9 what's going on and what information you're asking from 10 the licensees, what they are submitting, I mean, not just 11 a description of them. 12 MR. KING: No. You would like to get into the 13 pilot programs I understand. k'- ') 14 MEMBER APOSTOLAKIS: Yes, in detail. Okay. 15 MR. KING: Yes. 16 MEMBER APOSTOLAKIS: Sure. 17 (Slide) 18 MR. KING: We developed various drafts of all 19 of these guides and SRPs starting back around September. 20 The Committee has received copies of earlier drafts. We 21 in the December-January time frame had spent some more 22 time doing internal management review. We've now received 23 a staff requirements memorandum from the Commission on 24 four policy issues that we had sent up previously. (Qj 25 And, as a result, back in mid January we sent l l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
118 l l 1 to the Committee an updated reg guide and SRP on the fs 2 general framework. We expect today to provide updated I \ % ,/ . 3 drafts on the application-specific reg guides and SRPs 4 except for in-service inspection, which will come at a ! l 5 later date. 6 As I mentioned, we had a meeting with the 7 subcommittee on January 28th on the general. And we have 8 a meeting scheduled on February 20th-21st with the 9 subcommittee on the application-specific activities except i 10 for ISI. As I had mentioned, we had gotten an SRM from 11 the Commission. We'll talk about that in a little more 12 detail later. , i 1 13 The purpose of today's presentation is to .
/~N :
\) 14 update you on the changes that have been made on the l 15 general reg guide and SRP. I'll briefly summarize the l 16 approach that's being taken to respond to specific 17 quest 1ons raised at the subcommittee meeting and solicit 18 feedback from members. 19 We're not asking for a letter at this point in 20 time, but we are going to ask for a letter after the March 21 full Committee meeting. 22 (Slide) 23 MR. KING: The chedule we're on now is to 24 provide a package to the Commission by the end of March, (Al,j 25 which means we do need something after the March full NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234 4433 WASHINGTON D C. 20005-3701 (202) 234-4433
119 1 Committee meeting, the Committee's views in a letter 2 addressing the general reg guide and the (~- L) 3 application-specific ones except for ISI. 4 (Slide) 5 MR. KING: I had mentioned we had gotten some 6 feedback from the commission in the form of a staff 7 requirements memorandum on January 22nd. It gave feedback 8 on four policy issues that we had sent up back in October, 9 I believe. Those four policy issues were: 10 performance-based regulation, use of safety goals for 11 plant-specific application; risk-neutral versus risk 12 increase; and how to deal with, a recommended way to deal
-s 13 with, changes in the ISI under the current regulations. \ ' '} 14 In general the guidance we got back from the 15 Commission did not change the direction that we had been 16 heading in putting the drafts together. The guidance did 17 not result in any major changes to what we had been doing, 18 did ask for some additional things to be done and 19 additional information to be provided to the Commission.
20 Just quickly, on performance-based regulation, 21 we had recommended to the Commission that we use 22 performance-based approaches wherever possible in 23 implementing these risk-informed changes. l l 24 The Commission endorsed that. They also asked 7-. (_/ 25 for a more comprehensive plan that would take a look at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234 4433 l
120 1 implementing performance-based initiatives outside this e' 2 risk-informed area. So the staff was asked to put v 3 together a separate plan I believe by August of '97 for 4 that. 5 The Commission also asked for a summary of how 6 performance monitoring is being addressed in the pilot 7 programs. And we owe them a separate response on that. 8 Use of safety goals for plant-specific 9 application. We recommended that be done. The Commission 10 tentatively approved using the safety goals in that 11 fashion but also requested OGC, the legal arm of the l 12 agency, to put together a legal analysis on the use of 4
,3 13 numerical guidelines in plant-specific decisions,
addressing things like the potential for litigation and 14 15 what if the PRA changes later on. Do you have to come !
16 back and change your decisions that you made previously? 17 So they are on the hook to put together an analysis and i 1 l 18 provide it to the Commission. 19 Risk-neutral versus risk increase. What we 20 recommended was that in this process, changes to a CLB 21 should be allowed to result in small increases in risk 22 under certain conditions. The Commission endorsed that Please tell us what "small" means and what l l 23 and said: 24 "under certain conditions" means. I think the reg guide, p(_) 25 the draft reg guide, and SRP do that. And we'll talk NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE tSMND AW , N W (202) 234 4433 WASHINGTON. D C. 2000 5 3701 (202) 234-4433
121 1 1 about that. j l g-~g 2 And then, finally, the last one was more of a V 3 process issue, not a technical issue. But the Commission , 4 endorsed the staff's recommendation that the current rules 5 allow implementation of ISI changes under what they call 1 6 an acceptable alternatives provision. So no rulemaking is l 1 7 needed. I 8 (Slide) 9 MR. KING: The major changes that we made in 10 the general reg guide and SRP since the version that you 11 had seen back in November were that: first, we have added 12 some emphasis on what we call the overall expectation of
,_ 13 improved safety.
( 4
'~# 14 There was a concern that the earlier drafts 15 were worded -- someone described them as a road map for ,
I l 16 how to increase risk. And, clearly, as a safety agency, ; 17 we didn't want to send that message. 18 We think that by using risk insignts in the 19 long term, it s going to result in safety and that when 20 licensees are putting together their applications, they 21 ought to be looking at the total picture, both where risk 22 tells them they ought to improve safety and where risk 23 tells them there's unnecessary burden as well as look at 24 the cumulative impact in changes. So we put that (3 emphasis, more of that emphasis, in the regulatory guide. (_) 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
122 1 And you'll see that right up front in the package. g3 2 We have now used the safety goal subsidiary l (~~)$ 1 3 objectives to define what we call insignificant risk. And ) l 4 we have used those in the description of what changes in 5 risk are allowed to define what the Commission asked for 6 in terms of the word "small." 7 Basically what we have done is we have removed 8 the figures that were in the reg guide that had core 9 damage frequency and LERF versus delta CDF and LERF. And 10 we have defined basically three regions in risk space 11 where reviewing changes to a CLB would either be 12 acceptable or unacceptable and require certain levels of 13 review. O>
\
Basically we have said is if a plant's 14 j 15 baseline core damage f requency is greater than 10~' or its 16 large early release frequency is greater than 104, we 17 would except changes to CLBs would be in a direction to 18 decrease risk.
19 We have also said that if changes are very 20 small and the plant's core damage frequency is less than 21 10 4 or its large early release frequency is less than 10-5, 22 changes in CDF, small changes in CDF, or LERF down in that 23 region would likely be acceptable and probably in some 24 cases would not require the rigorous sensitivity analysis, 13) (m_ 25 uncertainty analysis, and so forth that may be necessary NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 234-4433
l 123 l 1 to get closer to the benchmark values. 2 Then there's the middle in the region. The
,f-C)' 3 region is about a factor of ten below the benchmark CDF 4 and LERF values. And the regulatory guide says we're 5 going to look very closely at plants that are in this 6 region and are requesting changes that increase calculated 7 risk.
8 That may require some additional analysis on 9 the licensees' part and will certainly trigger some 10 additional review on the staff's part, including 11 additional management review. And there are a number of 12 factors in the reg guide that are examples of the kinds of
,_s 13 things we would be looking at.
I \
\# 14 We have expanded the discussion on 15 uncertainties. And we're updating the appendices to the 16 general reg guide and SRP, which will be in the package 17 that you'll get today.
18 MEMBER APOSTOLAKIS: I have a comment. Your 19 second bullet seems to use the word " insignificant" and 1 . 20 "small risk" interchangeably. I would not do that. I 21 think insignificant is different from small. 22 Insignificant is something that I don't care about. Small 23 is something that's higher than insignificant but I 24 declare it as small. p (_,) 25 I don't think it would be a good idea to use NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. l (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433 l
124 1 the words the way they are used there, that we have (w 2 defined what is insignificant and anything below that is (ms) l l 3 small. l 4 It's just semantics, but sometimes these 5 things make a difference. 6 MR. KING: All right. We'll take a look at 7 that. 8 (Slide) 9 MR. KING: Just quickly, the overall approach j l 10 in the reg guide and SRP, you'll recall the November I 11 version had a four-step process. The current version 12 still has a four-step process. The four steps are: 13 define the change, do the engineering analysis, define 7- i I \ ') 14 your implementation and monitoring strategy, and then 15 submit the documentation that's requested. 16 Basically under the engineering analysis, we 17 have five what we call fundamental safety principles. I' 18 Those are: must meet the regulations or propose a change 19 or an exemption, must maintain defense-in-depth, maintain l 20 sufficient safety margin, have no significant increases in 21 risk to public health and safety, and implement the change 22 utilized performance-based monitoring and feedback 23 strategies wherever possible. 24 The reg guide expands on each of those as to n(,- 25 what is meant and provides some subelements and some NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
125 examples of what we mean in each of those principles. 1 t (x 2 Now, we're going to come back a little later and talk more 3 in detail about the defense-in-depth and sufficient safety 4 margin. 5 It also has what we call expectations on 6 implementation. Those are sort of subelements under the 7 principles. And they basically emphasize the factors of: 8 We expect the licensee to assess all safety impacts in 9 looking at the proposed change. We expect the scope of 10 the analysis supporting the change would cover all 11 systems; structures; components; operating modes; 12 initiators affected by the change; and should reflect the 7s 13 as-built, as-operated plant. 14 (Slide) 15 MR. KING: We've defined what we call some 16 benchmark risk levels for decision-making. There are two 17 of them: one for core damage frequency of 10-* per reactor 18 year. That's the value endorsed back by the Commission in 1 19 1990 as a benchmark for accident prevention. And then ,
\
4 20 we've defined for large early release frequency a 10 per ' l 21 reactor year, which is consistent with the quantitative l 22 health objectives. And it's also consistent with the 10-* 23 and the Commission's endorsed value of .1 conditional ' 24 containment failure probability. l (3 (_) 25 We have said that proposed changes to the CLB NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234 4433 WASHINGTON. D C. 20005-3701 (202) 234-4433 l
126 1 should be made in small increments. And we have defined rx 2 what those are, which are basically less than ten percent 3 of the benchmark CDF and LERF values. 4 And, as I mentioned, when you get close to the 5 benchmark CDF and LERF values, there will be additional 6 management review. And we think between the benchmark 7 values and limiting the CLB changes to small increments, 8 that those two things together ensure no significant 9 increases in risk. And I think we'll revisit the words to 10 make that clear. 11 We expect a licensee to perform uncertainty 12 and sensitivity analysis appropriate for the proposed 13 change. Now, we've left a lot of flexibility in the reg O i i
'# 14 guide and SRP for the licensee to decide the extent of 15 that analysis that needs to be done, but the general l
16 thought is the closer you get to the benchmark values, the 17 more rigor we would expect in that area. 18 We have put the expectation in that we expect 19 quality analysis and talked about some ways to achieve 1 20 that. Clearly, whatever they do we expect would be ] 21 available for public review. Then there's the performance l 22 monitoring and the documentation that's part of the i 23 overall approach. 24 At the end of the January 28th subcommittee e
\_,/ 25 meeting, we jotted down six items that the subcommittee NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
(202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
1 127 ! I I wanted to talk in more detail about today. And those are ,g 2 listed on this page. N)
~'
What I've got, the remaining part of the ! 3 I 4 presentation, is a page on each of those. 5 (Slide) 6 MR. KING: So starting with defense-in-depth ; 7 on Page 10, we have an overall defense-in-depth principle i 8 that says maintain defense-in-depth. Now, the reg guide 9 also has six subelements that try and explain what that 10 means. Those six subelements are listed here on Page 10. 11 The question that came up in the subcommittee 12 meeting was: What's the role of PRA in evaluating these ; 1 13 six subelements? And there was a concern that, as stated, r) 14 these basically said: Let's do the traditional 15 application of defense-in-depth. And we can't change from 16 that, even though we have a PRA in our hands. l 17 George proposed som words to try and clarify 18 that. And I think that we have agreed that's a good idea 19 to try and clarify that because we do believe PRA has a 20 role to play in how you look at these various subelements. 21 (Slide) 22 MR. KING: So we're going to propose some 23 clarification that goes into the reg guide in this area. 24 And basically that clarification is shown in two bullets r^ (_)T 25 on Page 11. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 923 RHODE ISLAND AVE., N W. (202) 234-4433 WAC,MNCiON D C. 20005-3701 (202) 234-4433
128 1 MEMBER APOSTOLAKIS: I agree on Page 11, you j f- 2 are really beginning to talk about guidelines. On 10, is \~/ 3 there another word to substitute for " guidelines"? I l 4 mean, these are not really principles, are they? I 5 MR. KING: No. 6 MEMBER APOSTOLAKIS: But this is the idea of 7 defense-in-depth. 8 MR. KING: The principle is maintain I 9 defense-in-depth. 10 MEMBER APOSTOLAKIS: Okay. 11 MR. KING: How do you do that? 12 MEMBER APOSTOLAKIS: Yes. ( l _ 13 MR. KING: These are some ideas as to: What I
\ 14 do you look at when you're trying to meet 't principle?
15 MEMBER APOSTOLAKIS: I think L. juidelines l 16 really are what you're going to talk about in a moment. 17 When you're here -- I mean, for example, it would be 18 desirable to maintain defenses against human errors. I 19 mean, that's really the spirit of this, isn't it? l 20 I mean, it's semantics again, but I think For me guide.'.ines I 21 these are things that are important. 22 means you're telling people how to do things. And this is 23 more like -- 24 MEMBER CATTON: Definition.
) 25 MEMBER APOSTOLAKIS: -- definition or --
(_f l NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
129 1 CHAIRMAN SEALE: To the elements of defense. 2 MEMBER APOSTOLAKIS: To the elements of
/m\
V 3 defense-in-depth. I don't want to call them " principles," 4 but, I mean, it's -- l 5 CHAIRMAN SEALE: " Elements" is good, " elements 6 of defense-in-depth." 7 MEMBER APOSTOLAKIS: Do you want to call it 8 that? 9 MR. KING: Okay. I have no problem with the 10 word " elements." 11 MR. HOLAHAN: I think it's guidance in the 12 sense that these are things that we expect licensees to 13 think about and inform us. ( \ 14 MEMBER APOSTOLAKIS: Right, right. 15 CHAIRMAN SEALE: Yes, right. 16 MR. KING: Things we would expect them to 17 address in their submittal. 18 MEMBER APOSTOLAKIS: But they are not absolute 19 criteria. 20 MR. KING: No. 21 MEMBER APOSTOLAKIS: I mean, there may be some 22 degradation of the independence of barriers, but you 23 should evaluate that in the context of a proposal change; 24 right? ( 1 Q 25 MR. KING: Yes. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
130 1 MEMBER APOSTOLAKIS: So it would be desirable l
,n. 2 to maintain that, but you are not absolute. We are not l ' N.
3 saying, " Gee, you degraded it. That's it." I think 4 that's the spirit of this. 5 MR. KING: Yes. 6 MEMBER CATTON: Maybe it's characteristics. 7 MEMBER APOSTOLAKIS: Yes, elements, 8 characteristics, or some other thing. 9 MR. KING: Yes. But I think these are the 10 kinds of things we would expect a licensee to come in and 11 address in the submittal, -- 12 MEMBER APOSTOLAKIS: Exactly, yes. g 13 MR. KING: -- "What do I do in each of these 14 areas." 15 MEMBER APOSTOLAKIS: So we need another word, 16 I think. 17 MR. KING: What we're proposing to add to the 18 reg guide are some words that basically accomplish the 19 following. I call it guidelines for application of the 20 defense-in-depth principle. But whatever we call it, 21 we're basically going to say where you have items that are 22 not addressed by the PRA, for whatever reason, or you have 23 high uncertainty coming out of your PRA, we would expect 24 basically the traditional engineering judgment is used in l 25 applying defense-in-depth. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, O C. 20005-3701 (202) 234-4433
131 1 For areas where you do have a good risk
,y 2 analysis, we would expect people to look at what that risk
(l 3 analysis says and help guide the application of 4 defense-in-depth and to use as a basis for demonstrating 5 that those six elements are met or the change that's being 6 proposed on any of those elements is appropriate. j 1 l 7 Again, you haven't seen the exact paragraph, 8 but that's basically the context of what we're trying to 9 say. 10 MEMBER APOSTOLAKIS: In other words, what 11 you're saying in the second bullet is the PRA quantifies 12 certain things. So I have a contributor that has a 13 certain frequency distribution. i
- kl 14 What defense-in-depth is telling me is that 15 it's not just the frequency and the distribution itself. ;
i 16 I want to look into it and try to understand where these i 17 elements are coming from. That's really what it's saying. 18 MR. HOLAHAN: Yes.
'. 9 MR. KING: Yes. For example, you have an 20 outlier in risk. You may say, "What's going on here? Do 21 I have defense-in-depth the way I really thought I had 22 it?"
23 MEMBER APOSTOLAKIS: Now, some of it is l l 24 already built into the distribution because if you don't ' (~T 25 have defense-in-depth in the sense of redundancy and all ( ,/ l NEAL R. GROSS j COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
132 1 of that and diversity, then the numbers presumably will be 2 high. [s) N~/ 3 So some of it is already in the numbers, but 4 we go beyond that. And I think that's reasonable. That's 5 reasonable. l l 6 (Slide) 7 MR. KING: The second issue had to do with 8 safety margins. And the principle basically says maintain 9 sufficient safety margins. And there was a question as 10 to: How do you judge what's sufficient? 11 The two guidelines or elements that we have in 12 the reg guide under that principle are shown here on this 13 slide as the first two bullets that you meet codes and l \ ) N' 14 standards that are approved for use. And if you've got 15 certain safety analysis acceptance criteria, a lot of that 16 is deterministic criteria, like Part 100 dose guidelines 17 and so forth, that still have to be ie t as part of the 18 change. 19 Now, we are not proposing any additional words l l 20 into the regulatory guide or SRP in this particular area. l 21 We felt that between the existing deterministic criteria l 22 and between having a risk assessment, that you really can 23 take a look at your safety margins and what's changed from 24 the original versus the proposed change and make a (O ,/ 25 judgment on whether it's still adequate. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
133 l l 1 Clearly if you're still meeting the l l 7g 2 deterministic requirements, it should still be adequate, t t
%J 3 even though maybe your Part 100 dose calculation is a 4 little higher than it used to be. As long as it's still 5 meeting the Part 100 criteria, it should still be 6 adequate. I 7 So we're not proposing any change to what's in j l
8 there at this point. 9 MEMBER APOSTOLAKIS: 1 guess I'm a bit l 10 confused about this. Proposed provisions provide 11 sufficiene margin to account for analysis and data ! 12 uncertainty. Now, that analysis is a PRA analysis or 13 could be a PRA analysis?
/' ,
14 MR. KING: Could be, could be. 15 MR. HOLAHAN: In the deterministic side, 16 there's usually a conservative methodology that's used. 17 MEMBER APOSTOLAKIS: But if you have 18 sufficient margin, perhaps you will not have analysis 19 uncertainty. I mean, that's what I'm trying to 20 understand. I mean, if you have sufficient margin, then 21 the probabilities you are going to get will show that, 22 will reflect that, won't they? And then you will say, 23 "Now, go back and make sure that" -- 24 MR. BOB JONES: Let me try where this comes
\
- (j 25 from.
1 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
134 1 MEMBER APOSTOLAKIS: Okay. Okay. gS 2 MR. BOB JONES: In the regulatory standards, () 3 for example, in GDC for fuel design, which are at a 4 general level, a licensee has in its licensing basis today i 5 a defined safety standard. It's a DNB limit of whatever , 1 l 6 from some method, 2,200 degrees, certain calculations, ' 7 whatever it is. 8 If they propose to change what the staff has 9 already accepted as an acceptable criteria and change that 10 margin, then at that point they need to come in with the i 11 supporting analysis and data and why that still meets the ! l 12 appropriate regulatory standard. And when they do that, _s 13 they need to look at the data uncertainty and any analysis t
14 uncertainty that may be associated with it. ;
15 So what we're saying is the standards that are ! 16 currently out there that are acceptable to us can be 17 changed. But the burden when you do that is you have to 18 still demonstrate that you're meeting the underlying 19 regulatory requirement and that you're accounting for data 20 analysis uncertainties and the impacts of those safecy 21 margins. 22 So it's part of the principle of maintaining l l 23 consistency with regulations and also where if a 24 regulation hasn't gotten that specific you would have to O) (, 25 come in with appropriate analysis to support it. i
- NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE , N W l (202) 2344433 WASHINGTON. D C. 20005-3701 (202) 234 4433 l
1 ! 135 l 1 Let's go look at this in the area, for (~x 2 example, of if you wanted to have different repair 3 criteria for a steam generator you want to change the 4 repair criteria, you want to meet certain structural l 5 margins. You have to demonstrate with appropriate data j 6 how you detect it, why it's good enough, how it meets the 7 underlying safety margins to ensure tube integrity. 8 MEMBER CATTON: What if you find there's no 9 underlying regulatory requirement? In other words, you 10 have a regulation. But you try to do this, and you find, 11 gee, there's really no basis. Does that mean you can l 12 ignore it? What do you do? 1
,_ 13 MR. KING: I don't think you ignore it. You ,
'('-') 14 can -- l 15 MEMBER CATTON: I can give you some examples i 16 in the fire arena where this is the case. But what do you 17 do? 1 18 MEMBER APOSTOLAKIS: Can you give one?
19 MEMBER CATTON: The golden rules and magic l 20 numbers. It's in the papers. There's whole series of 21 them: Height of things, where you put this, that, and the 22 other. i
- 23 MEMBER APOSTOLAKIS
- Do they all know what l
I j 24 that is? p. (_ 25 MEMBER CATTON: I don't know. Do you know the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. (202) 234 4433 WASHINGTON. D C. 20005-3701 (202) 234-4433 1
l l 136 ! I paper golden rules and magic numbers? I can get it for p 2 you? i b 3 MEMBER APOSTOLAKIS: Well, let me again tell l l 4 you what I don't understand. j 5 MR. HOLAHAN: Can I go back and change l l 6 something from one of the previous answers? 1 7 MEMBER APOSTOLAKIS: Yes. 6 MR. HOLAHAN: I think if you read this bullet l 9 carefully and see it in the context of the document, I l 10 don't think it really, not normally -- it doesn't normally 11 apply to the PRA analysis. 1 12 I think it's really for -- because it's 13 related to FSAR and licensing basis, I think it's the Ci 14 engineering and licensing basis analyses currently on the 15 plant, which might have a little piece of PRA in it 16 somewhere. But generally this is for the traditional 17 engineering analysis. 18 MEMBER APOSTOLAKIS: Now, what if I do a PRA 19 and in a certain situation I have a given margin and now I 20 reduce it? Okay? l 21 MR. HOLAHAN: I think these words don't apply 22 very well to a PRA. I I ! 23 MEMBER APOSTOLAKIS: They don't. l 24 MR. HOLAHAN. In a PRA you're doing best I
/^
( l 25 estimate analysis and assessing them, the uncertainties l l { NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
137 1 and margins. You're not putting them in there, gg 2 MEMBER APOSTOLAKIS: Right. But I may do Q 3 something that presumably reduces the margin. And then I l 1 4 argue probablistically that that is reasonable. So the ! l 5 criterion there will be: Is delta CDF within the range 6 that Tom showed us and this and this and that or, in 7 addition to that, somebody might say, " Gee, but I really l 8 don't like the fact that you're reducing the margin"? l 9 It's really the same conceptual problem that I j 10 had with defense-in-depth. You have to have some guidance l 11 how you implement these principles. 12 MR. HOLAHAN: In some sense, I don't think you 13 need this principle for the PRA analysis because the i f) 14 margins and the uncertainties are taken care of. 15 MEMBER APOSTOLAKIS: Yes. 16 MR. HOLAHAN: It's only in the engineering 17 analysis that you want some assurance that the pipe 18 doesn't break or the pump really starts. 19 MEMBER APOSTOLAKIS: So the last line, then, 20 perhaps doesn't belong there? 21 MR. HOLAHAN- Or it doesn't apply to PRA 22 analysis. It applies very much to engineering 23 calculations. 24 MEMBER APOSTOLAKIS: Yes, yes. So that will O (_,/ 25 be clear in the t. ext. l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE , N W. (202) 234-4433 WASHINGTON. D C 20005-3701 (202) 234 4433
138 1 MR. KING: But in theory let's use the Part 7- g 2 100 dose guideline as an example. You have a 25-rem whole L) 3 body limit now. A plant, say, currently has a 20-rem 4 c11culation and they want to do souething. It will raise 5 that to 25. It clearly would meet the current 6 regulations, but you may want to look at that from a risk , 7 perspective and see: From a risk standpoint, what does 8 that change do? l 9 So I guess I think the safety margin is 10 involved in looking at the PRA as well as looking at the 11 deterministic stuff. I guess I tend to agree these words 12 don't meld the two together very well. l 13 MEMBER APOSTOLAKIS: But if I look at the PRA, i
\' 14 then I will apply the earlier criteria.
15 MR. HOLAHAN: Right, right. We have another 16 principle that I think captures our guidelines for PRA. , i 17 That'e why T don't think it needs to be captured here. 18 MEMBER APOSTOLAKIS: Okay. j 19 MR. HOLAHAN Also I think safety margins I 20 think tend to go to individual component design m ore than 21 it does to overall plant risk. So what I see as the 22 bigger picture questions of "Are the risk changes small 23 enough and acceptable?" I think are covered by the PRA 24 guidelines that we just talked about. r's (s,) 25 And this tends to make sure that, even though NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
139 l 1 the risk numbers are low, you didn't design a pipe that's 2 likely to fail and then prove to yourself that, well, t, 3 failure of the pipe is okay because the mitigation systems l l l 4 are very reliable. So it's that good engineering margins 5 should be in all engineered systems. l 6 MEMBER APOSTOLAKIS: Isn't that against some 7 formal defense-in-depth? l 8 MR. HOLAHAN: Yes, it is. Sure. l 1 9 MEMBER CATTON: It's the safety factors you 10 put into the system. You could substitute. For " safety I 11 margin," you could put " safety factor." In the definition l l 12 that he's giving us, he could. l l
, 13 When you start talking about safety margin, I C 14 think it implies something that you don't know. It's very 15 difficult to determine what your real safety margin is.
16 But you know the safety factor that you plan to have into i 1 l 17 a particular piece of equipment. , l 18 MEMBER APOSTOLAKIS: Would it be too radical 19 to combine safety margins with defense-in-depth and say 20 there is one thing that we really want to spread the i l 21 contributions to risk? 22 MR. HOLAHAN: Yes, I think that would be too 23 radical. l 24 MEMBER APOSTOLAKIS: Why is that? n Well, I think the concepts -- ( ,/ 25 MR. HOLAHAN: I NEAL R. GROSS i COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C 20005-3701 (202) 234-4433
140 1 maybe they could be combined, but it seems to me that it's (~'g 2 clearer in this sense because safety margins are something G 1 3 built into most engineering analyses. And you can define, 4 whether it's safety factors or margin to burst or 5 something like that. 6 Defense-in-depth is not a numerical value. a 7 You don't calculate, you know, this system has two and a 8 half layers of defense-in-depth. It's more of a 9 philosophical view of seeing that the design looks like it 10 has appropriate levels of prevention and mitigation, 11 rather than a numerical analysis. 12 MEMBER APOSTOLAKIS: So there is, then, less 7_ 13 need for this principle because something that's ( J 14 quantifiable would be a part of the PRA? 15 CHAIRMAN SEALE: May I offer -- l 16 MR. HOLAHAN- But I think it's normally not ! 17 part of the PRA. The PRA doesn't get to the level of 18 engineering detail that's covered here, I think. i l 19 MEMBER APOSTOLAKIS: Unless we involve this 20 other principle on Page 8, " Perform uncertainty and 21 sensitivity analysis appropriate for the proposed change." 22 If it's appropriate, they may have to go down there to do 1 23 the details. l 24 See, PRA is not just a systems approach. You f} (s / 25 go as far down as you need to to support your position. , 1 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 23 4 433 WASHINGTON, D C. 20005-3701 (202) 234-4433
141 1 CHAIRMAN SEALE: Well, isn't it true that when i
.f 3 2 you're talking about the current licensing basis, you're
,LJ 3 generally talking about a bounding condition and a margin 4 of safety that is inherently defined by the conservatisms l 5 that are built into that bounding condition? 6 What happens when you go to a basis which 7 includes a best estimate assessment of system performance 8 with allowances or with considerations given to 9 uncertainties and a margin, then, that comes out of that, 10 out of your understanding of how good the best estimate 11 is? 12 Now, when you've done that, you've put the 13 performance estimate on the table. You've gone from a 14 bounding to a best estimate evaluation of system 15 performance. And that frees up, at least intellectually, 16 what the margin should be because now your margin is with 17 respect to a different point. It's the best estimate now, 18 not the bounding analysis. 19 What this says is that when you make that 20 transition, you've still got to do the margin assessment, 21 but it's with respect to the uncertainties that are 22 inherent now in this best estimate methodology you're 23 using, rather than in the old bounding methodologies. i l 24 MEMBER APOSTOLAKIS: This is all within the l
,\
l 25 deterministic framework, isn't it? NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
l 142 I i 1 MEMBER CATTON: No. l 2 CHAIRMAN SEALE: Well, it.'s not limited to r] 5
\ ,
3 that. l 4 MEMBER CATTON: You do t he best estimate. You l 5 have to roll it in uncertainty, a:.3 it becomes risk. It i 6 becomes a PRA-type. It doesn't have to be risk, but -- 7 MEMBER APOSTOLAKIS: No. Probablistic, I ; l 1 8 mean, but -- 9 CHAIRMAN SEALE: It's a best estimate. 10 Actually. 11 MEMBER CATTON: -- the uncertainty associated 12 with a particular device doing what it's supposed to. , 13 It's not a fixed point. ?
\ 14 CHAIRMAN SEALE: It's negotiable. And this is 15 the basis for the negotiation. 1 l
16 MEMBER APOSTOLAKIS: Yes. I mean, I don't l 17 understand in a PRA context what's a best estimate. There 18 isn't such a thing. You've got a whole distribution. I 19 mean, you can determine a mean value or a this and that, 20 but the best estimate is -- l 21 MEMBER CATTON: Then it's a mix. 22 MEMBER APOSTOLAKIS: It's a traditional -- 23 MEMBER CATTON: The heat transfer coefficient 24 is ten plus or minus. (3 U 25 MEMBER APOSTOLAKIS: In the seismic analysis, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
143 1 isn't there such a thing as a margins approach that -- g- g 2 MR. HOLAHAN- Yes, yes. U 3 MEMBER APOSTOLAKIS: -- has probabilities of 4 the HCLPF and all that? , 1 5 MR. HOLAHAN: Yes. 6 MEMBER APOSTOLAKIS: So that's all 7 probablistic there. 8 MR. HOLAHAN- Well, that's true. And I think l 9 the way the reg guide is structured, in addition to saying , i 10 that there's this principle related to safety margins, it i 11 suggests that you can address it either th.' ugh a 12 traditional engineering analysis or through PRA insights. 13 And I think the seismic margins analysis is a way of
)
6 14 showing margin through a probablistic approach. l 15 I have to say but in most cases I expect 16 safety margins will probably be shown through engineering 17 analysis than probablistically. But I think the reg guide 18 leaves that open for the licensee to develt, an argument 19 one way or the other. 20 MEMBER APOSTOLAKIS: All right. 21 MR. HOLAHAN. What we have now, for example, 22 is this 3 times margin to burst and 1.4 times margin to 23 burst under steam line break conditions. Ar.d so those are 24 these kind of traditional engineering safety margins. (~T
'(_) 25 But conceptually in the steam generator world, NEAL R. GROSS i
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l 144 1 we're also trying to show margins of safety with respect gx 2 to core damage, large early release, and things like that. () 3 MEMBER SHACK: But then you go back to 4 probability of burst. You can evaluate it that way also, . I 5 probablistic alternative. l 6 MR. HOLAHAN: Yes, yes. In effect, I think 7 the voltage-based criteria are that sort of thing. Yes. 8 MR. KING: Move on? 1 9 CHAIRMAN SEALE: The Chairmar is out, but 1 10 that's all right. 11 MEMBER CATTON: You're the Chairman. 12 (Slide) I i 13 MR. KING: The third issue we call i
\') 14 plant-specific LERF. And, as I remember, this sort of had 15 a couple of sub-elements. One was we' re proposing or-16 value for the large early release frequency that would be 17 universally applied and would be a constant.
18 There was a question as to: Why not let that 19 be different either based upon site characteristics of a 20 plant or maybe be different by plant type: BWRs versus 21 PWRs, for example? 22 We're not proposing a change in what was in 23 the regulatory guide, which, as I said, was a single 24 value. We recommended 10 4 per reactor year along with the
<~s k ,)
s 25 region of increased management attention when you're close NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 234 4433
145 i l L .. 1.. to.that. _ _ _ . ! r- 2 We feel that that is a reasonable number. t
\_-
3 It's based upon providing reasonable that the safety goal l l 4 QHOs are met without being de facto new goal. 5 We think it's consistent with work we did 6 several years ago when we looked at what was called the 7 10 4 large release guideline that the Commission asked us 8 to investigate and we found out if it Jas applied would I 9 essentially be a de facto new goal because it was much l 10 more conservative than the OHOs. 11 We also think it's consistent with the 10" CDF 12 and the .1 conditional containment failure probability 13 safety goal subsidiary objectives that the Commission 7.-- ! (' ) 14 endorsed back in 1990. 15 We also think that sticking with a single l 16 value has some other advantages that allows licensees to 17 just use Level 1 and Level 2 PRA only. It avoids the 18 uncertainty assoated with Level 3 analysis which right 19 now the only method we have or the only uncertainty we 20 look at in Level 3 is the uncertainty associated with wind 21 rose, but we know there are a lot of other uncertainties 22 in Level 3 analysis. 23 We think it's consistent with decoupling 24 siting from plant design, which the Commission told us to I (_/ 25 do about five or six years ago. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE , N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
1 146' 1 VICE CHAIRMAN POWERS: Are you saying that you 2 think the uncertainty in Level 3 is overwhelming in f w\ t V 3 comparison to 1 and 2? 4 MR. KING: No, I'm not saying it's 5 overwhelming. I'm saying we don't know what it is. I'm 6 not sure how we would deal with it. i 7 VICE CHAIRMAN POWERS: You haven't adequately I 8 quanitified it? j 9 MR. KING: Right. And we think providing ) 10 simple uniform, consistent guidelines to all plants is i
)
11 reasonable. We think that the 10-5 does provide some ) l 1 12 flexibility for BWRs versus PWRs, for example, to adjust '
,s 13 core damage frequency versus containment performance in U 14 meeting that.
15 So we don't really see a need to have more 16 than one single value. Therefore, we're not recommending 17 anything different than what's been in there all along. 18 MEMBER KRESS: Tom, what is your basis for 19 that first sub-bullet that provides reasonable assurance 20 that the safety goal QHOs are met? 21 MR. KING: We've gone back and looked at 22 NUREG-1150 and LaSalle PRA and looked at: If you want to 23 meet the OHOs, what kind of LERF do you need based upon 24 the early containment failure numbers that were in those 25 PRAs and based upon the Level 3 PRA information that was NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
147 1 in there, similar to what Rick Sherry presented? -- I ,3 2 think it was at the subcommittee meeting -- and then
~
3 looked at the fact that most of that analysis was looking 4 at full power only and putting some margin in to account 5 for low power and shutdown, external events and so forth. 6 We think 10-5 is a reasonable number that would 7 assure you meet the early fatality QHO, which is the 8 controlling one. I 9 MEMBER KRESS: I agree that that's the 10 controlling one. How can you assure yourself that such a 11 value encompasses all of the sites? This will be 1 12 site-dependent. l 13 MR. KING: It will be site-dependent. The i [ T l 14 plants that NUREG-1150 and LaSalle looked at covered all 15 the containment types, and they covered high population 16 and low population sites. And I guess one of the 17 assumptions at this point is that that's a reasonable set 18 of -- 19 MEMBER KRESS: Reasonable plant -- 20 MR. KING: -- plants to look at. 21 MEMBER KRESS: Reasonable bounding set for all 22 the sites. 23 MR. KING: Yes, and then the containment 24 types. Now, we don't have Level 3 information from the 7 (_,/ 25 IPEs. A few submitted it but not many. So we don't NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
148 1 really have a big database to go back to beyond that and , ,3
, 2 look at.
i] 3 MEMBER APOSTOLAKIS: Could someone derive 4 another LERF guideline for their plant based on where they 5 are or is that -- 6 MR. KING: Based upon their site and their -- 7 MEMBER APO9TOLAKIS: Yes. Let's say 5 times 8 104 9 MR. HOLAHAN: I think if you think of it in 10 the context of a reg guide, what we're saying is this is 11 the purpose of a reg guide is to define a set of analyses 12 and guidance that the staff would find acceptable, which 13 says not that if a licensee proposed something different
!\ ') 14 it would necessarily be rejected.
15 But the licensees ought to understand if they 16 send in something in conformance with these guidelines, 17 they ought to expect it to be approved. So it's sort of a 18 one-sided test. 19 What we're saying is this 10 4 appears to be 20 sort of a conservative bound of at least the range of 21 plants that we've looked at. So we would accept it. If a 22 licensee wants us to accept something different, I think 23 there's a lot of additional burden of proof for them to 24 justify why this makes sense for their circumstances.
!,f~ -). 25 MR. KING: There's nothing in the reg guide NEAL R. GROSS COURT PEPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
149 1 that says they can't make that proposal. They could come rx 2 in and propose it, but -- IN_-] . 3 MEMBER APOSTOLAKIS: I thought we were l 4 treating the CDF subsidiary goal and the LERF subsidiary l 5 goal differently in the sense that in the CDF case, you I 6 really can't do what you just said. I mean, they cannot 7 come and argue that the CDF could be 5 times 10-4 because 1 8 at least this Committee has recommended that we elevate 9 that to the same level as the QHOs. j 10 However, LERF appears to be more flexible. So 11 one could derive the site-specific goal for LERF. Now, 1 12 again, you don't want it to be -- i
,, 13 MR. HOLAHAN- In the legal context of granting
- I '
\#
14 license amendments, neither the QHOs nor any of these 15 guidance documents are actually in the regulations. Okay? 16 So I think even though we put a higher j 1 17 importance on a QHO and a Commission safety goal and a ! l
\1 18 formal adoption of that, in the legal licensing process, 19 that really doesn't have any stricter role than any of the 20 other guidance documents.
I 21 So in a legal sense, the CDF and the LERF 22 guidance values really play the same role. They are 23 indications of what the staff would find acceptable. And 24 in theory, a licensee could come in with a proposed CDF,
/~%
( ,) 25 baseline or change, that's different from what we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
1 i 150 1 suggested here. jT 2 But I think anyone who reads the record and (.) ? sees how serious the staff and the ACRS and others are 4 about treating these things shouldn't realistically expect 5 too receptive an audience. 6 MEMBER APOSTOLAKIS: I don't remember now, but 7 is it made clear in 1061 that there is a difference in the 8 way the staff is looking at CDF and LERF? l 9 MR. HOLAHAN: No, no. 10 MR. KING: No. 11 MEMBER APOSTOLAKIS: Should there be something 12 there to make it clear? 13 MR. HOLAHAN: I don't think it's necessary. (,- LY 14 MR. KING: Yes. I don't either. ; 15 MR. HOLAHAN- Legally they're the same. The 16 fact that I think we -- well, in fact, with a LERF value 17 as high as 10 ~ 5 , I think exceeding it is pretty serious, , l 18 too. When we used to talk about the 10", I think a lot of l 19 us felt that, well, maybe there's a good deal of margin l 20 here. 21 But I'm not sure I feel any more generous 22 about a 10-5 LERF than I feel about a 10-4 CDF. 23 MEMBER APOSTOLAKIS: Well, I guess what I am 24 questioning is we have a QHO, and that's what the { l b' 25 Commission gave us. Then we're establishing CDF goals, ; NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
151 1 LERF goals. p 2 MR. HOLAHAN. Yes. ( 3 MEMBER APOSTOLAKIS: Presumably we're trying 4 to be consistent, to have a self-consistent system. 5 MR. HOLAHAN- Yes. 6 MEMBER APOSTOLAKIS: But now it seems that the 7 site is really out of the picture, isn't it? 8 MR. HOLAHAN: Except that you will recall that l 9 as part of the range that we have been talking about, this ) 10 middle range with additional management attention, siting 11 is one of the additional factors that the staff ought to 12 take into consideration when it's making sort of one of 13 the more difficult judgments. 14 MEMBER KRESS: That means in reality, if they i 15 could stand a bigger LERF or CFP and still meet the QHO, 16 within that, if they were close to the margins, you would 17 give that more consideration? 18 MR. HOLAHAN: We would give it more 19 consideration. 20 CHAIRMAN SEALE: But you might need a full 21 scope, including all operating -- 22 MEMBER KRESS: To show that, right. 23 CHAIRMAN SEALE: -- ranges, PRA Level 3 in 24 order to make that point. x_) 25 MEMBER KRESS: To make that case. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005 3701 (202) 234-4433
152 1 MR. HOLAHAN. That's right. And if you look
,s 2 at the other considerations in that area, it calls for I \
3 additional analysis and treatment of uncertainties and 4 that kind of thing. 5 CHAIRMAN SEALE: What if I came in and I had a 6 full-scope Level 3 PRA with all the bells and whistles and 7 I made a proposal to you and I only based it on the QHO, I 8 didn't say anything about CDF or LERF? Would you consider 9 that to be a viable proposal? 10 MR. HOLAHAN: I guess I'd have to look at it. 11 Okay? I'm a bit skeptical, but, look, if the guidance 12 document that we.'re writing says yes, you know, we would 13 look at that.
,n \'
14 CHAIRMAN SEALE: Okay. 15 MR. HOLAHAN- But I don't expect to see a lot 16 of -- 17 MEMBER KRESS: I don't either. 18 CHAIRMAN SEALE: That would be pretty 19 hypothetical. 20 MEMBER KRESS: Along that, a similar, related 21 question. 22 CHAIRMAN SEALE: Yes. 23 MEMBER KRESS: It seems to me that the 10-4 and 24 .1 have been accepting you guys as a reasonable balance in rx C) 25 terms of defense-in-depth. Do you have a real reason for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
i 153 f 1 that or is that just consensus that's been around a while l 7x 2 and it looks like that's what people have been using so j
-, ]
3 long that now it's become ingrained in our thinking or is l I 4 there a reason for saying that's a reasonable balance? l l i 5 MR. HOLAHAN: I'm not sure that there's any ) I 6 philosophical basis for it. 7 MEMBER KRESS: It's a judgment call? I 8 MR. HOLAHAN: Well, in addition to a judgment 9 call, in some ways it's a matter of facing reality. I 10 mean, it is -- l l 11 MEMBER KRESS: You're right. l l 12 MR. HOLAHAN: It reflects the way many of the 13 designs are out there. Now, you could argue that as a 7-~)x \ k- 14 matter of principle, even though you would like balance in 15 the design, you certainly don't want a 50/50 balance which 16 says -- I mean, there is -- 17 MEMBER KRESS: This is arbitrary. 18 MR. HOLAHAN: Well, no because I don't think 19 they're equally valuable. I think preventing accidents is 20 more valuable than mitigating them. 21 MEMBER KRESS: So you would expect to see this 22 -- 23 MR. HOLAHAN: I would expect to see my CDF 24 expectations to be different from my containment l O) (, 25 performance. And whether it's -- NEAL R. GROSS ' COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234 4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
)
154 1 MEMBER KRESS: In several orders of magnitude, g- 2 that's -- t
%)
3 MR. HOLAHAN- -- and whether it's 10 , 10-2, or 4 10", 10 . But I wouldn't expet* it to be 10-2, 10-2, 7 5 think. That's not a good -- well, that's perfect balance, 6 but it's not a good idea. 7 MEMBER KRESS: There's really no way to arrive 8 at that number except by judgment on the -- 9 MR. HOLAHAN- I think it's a matter of 10 judgment. Now, I think you could say: When the value 11 gets above .1, if you wanted to pick a value of .5, that 12 really says you don't have much confidence in that
,. 13 barrier. And I think you've gone beyond the concept of O 14 defense-in-depth.
15 So in some sense you might argue .1 is a 16 balance point at which you say I have some confidence in 17 defense-in-depth, but I haven't put too much of my 18 protection -- 19 MEMBER KRESS: In that basket. 20 MR. HOLAHAN: -- in that basket because you 21 want most of your eggs in a prevention basket. That's 22 where it does the most good. 23 MEMBER KRESS: The way this question relates 24 to Bob's is I think that's the kind of thing you would
/'
k_,N) 25 think about if somebody really came in with just a QHO NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1P3 r<HODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
155 1 kind of -- i (N 2 MR. HOLAHAN: Yes, absolutely. If they came t ) LJ l 3 in with a QHO that said, " Core melt is likely, but we have 1 4 a fantastic containment," that doesn't sound too good. 5 If they said, "We have a fantastic system that 6 prevents core melts, but vur containment isn't so good," 7 well, I'm a little more receptive to that. But, frankly, 8 the way we'd really like to see it is what the reg guide l 9 says. 10 So the burden of explanation I think is on the 11 licensee's part. 12 MR. KING: You said you recall that 10-4 and a f_s 13 .1 were recommended by the staff back in the late '80s. I ( \ 14 think they were also endorsed by this Committee back then 15 as well. 16 MEMBER K' 00: Yes. This Committee endorsed 17 those numbers. 18 MR. KING: And we can dig out those old papers ) 19 and see what they say, but that's where it came from. 20 MR. CUNNINGHAM: And they were aired with the i 21 Commission, and the Commission went along with them 22 basically as well. l l l 23 MEMBER APOSTOLAKIS: You said, Gary, that the l l 24 QHOs and subsidiary goals have no legal standing. l V 25 MR. HOLAHAN: Yes. l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
4 - l 156 ) 1 MEMBER APOSTOLAKIS: Now, you also said -- 7- 3 2 well, Tom said earlier that the Commission has asked the U 3 Office of General Counsel to give them a position paper as 4 to how all of these things fit in the system. 5 MR. HOLAHAN: Yes. 6 MEMBER APOSTOLAKIS: Do you think that a year l 7 from now, two years from now these will have legal l 1 8 standing? 9 MR. HOLAHAN. No. That's not our current l 10 plant. To give them legal standing, it seems to me 11 there's only one way to do that. And that is to take the 12 Commission's policy statement and write it into the 13 regulations. So you would have a safety goal regulation (- l 14 of some sort. And that would give it legal standing. 15 And if you were to do such a thing, you could 16 put QHOs or CDF or LERP or whatever level you wanted to 17 put in there or you could just put in there the 18 qualitative safety goals. I mean, it has a number of 19 choices. But whatever you put in there has legal 20 standing. Whatever you don't is guidance. 21 The one other difference it makes to me is 22 when I get guidance from the Commission and even if the 23 staff thought that we had an extraordinary argument from a 24 licensee that something different from that guidance would /~'N (s,) 25 be acceptable, it seems to me the staff wouldn't accept NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
157 1 that. Probably because it's a Commission policy, we would ,- 2 have to go back to the Commission and have the commission i G 3 approve such a thing. 4 So the only thing that a Commission policy 5 seems to do is set the Commission's expectations so that 6 if the staff wanted to do something different, it probably 7 needs the Commission's approval to do so. 8 MEMBER APOSTOLAKIS: But if you are making 9 decisions using these numbers, what difference would it 10 make if they acquired legal standing? I mean, as a
- 11. practical matter, it doesn't make a different.
12 MR. KING: Well, you recall what the 13 Commission said when they asked OGC to do their review was \/ - 14 they used the words " legal implications." I agree with 15 Gary. They don't have legal standing. But the fact that 16 the staff is now considering this information in making 17 its decisions could potentially have legal implications 18 for these numbers in a PRA. And that's what the 19 Commission is asking. 20 MEMBER APOSTOLAKIS: What does legal standing 21 do to you? I mean, if you are to use them, I don't 22 understand what the difference would be. You are using 23 them. 24 MR. BOB JONES: Well, in the sense of if you o ( ,) 25 said that 10" CDF was an aosolute, there is no way we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE.. N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
158 1 could ever grant a license amendment without a complete m 2 demonstrate that it met the 10-4 CDF. v
)
3 And it may need to meet -- all modes may have 4 to have been fully analyzed. I mean, there are 5 implications associated with it that at times the 6 discussion we've had with the subcommittee about "Is that 7 a bright line or a soft line?"; it becomes a bright line, 8 period. 9 MEMBER KRESS: Can't you structure the rule in 10 such a way that it doesn't, though? 11 MR. HOLAHAN: Yes. 12 MR. BOB JONES: Well, you could do it, but I'm 13 just saying if you took it as the rule says, X, then i > U 14 violation of the rule now has other legal hurdles you 15 would have to clearly jump over. 16 I mean, there are exemption processes. For 17 example, you could still deal with it. But it becomes -- 18 the hurdle I think gets larger. You go from the low to 19 the higher by doing that. 1 4 20 MEMBER APOSTOLAKIS: You would lose I 21 flexibility, then. That's what you're saying? 22 MR. HOLAHAN. Normally when there's a rule 1 23 involved, you lose some flexibility because there are 24 additional standards to getting exemptions. If there were (} (< 25 a rule, one thing is I think it would be another difficult NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 2344433 WASHINGTON, D C. 20005-3701 (202) 234-4433
1 l 159 l 1 and time-consuming process to have such a rule. , i i 2 It might clarify some of the potential 7 w) ( ! v arguments abut backfits. l 3 To what extent is the staff's 4 insistence on using these guidelines versus some other 5 numbers a matter of a backfit? I think it would clarify 6 that role. l 7 I think the path we are on which does not t 8 involve a rule but involves using guidelines in the ; 1 9 decision-making, I think this is a viable approach that 10 we're on. We haven't run into any insurmountable problems 11 yet. I don't see anything that says that we need a rule 12 in order to implement risk-informed, performance-based ! 13 regulation. l {3 l
-- 14 MEMBE11 APOSTOLAKIS: I got my answer. Let's 15 go on.
l l 16 (Slide) l 17 MR. KING: Fourth issue raised was the 18 Committee noted that the general reg guide and SRP did not 19 have any guidelines on temporary changes in risk. What's j 20 in there, the CDF and the LERF values expressed, are l 21 expressed in terms of annual average CDF per reactor year, l l 22 for example. 23 We do in the technical specification reg guide 24 and SRP address temporary conditions because a lot of (3 25 those changes will deal with assessing changes to
,/
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160 1 allowable outage times, which by the very nature are (~} 2 temporary conditions.
\s' 3 You haven't seen the latest version of that 4 reg guide and SRP. You should be getting it today. But 5 basically what it has in there are two limits that are 6 expressed in terms of core damage probability and large 1
7 early release probability. I l 8 Those are really for the period you're in the ) 9 allowable outage time times the risk value caused by that 10 condition. Multiply those two together and come up with a 1 1 11 prrbability. And there are limits expressed. We're going 12 to discuss the basis for those at the February 13 subcommittee meeting. l 7- l ( l
'# Those limits on temporary risk are also 14 l 15 applied in addition to the annual average CDF and LERF 16 values in the general reg guide. Just as an example, if i l 17 you were to apply the core damage probability limit, it 18 would correspond to a CDF of 10-3 per reactor year for a
.3 5-hour period when you're in that AOT. In other words, 20 for the 5 hours you're in that AOT, if you were in that 21 for the full year, it would correspond to a 10~3 CDF. So 22 just to give you a feel when you look at it on an annual 23 number, that's the magnitude of CDF that we're talking 24 about that these numbers represent.
im ks) m 25 And we are going to solicit in the Federal NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
I 161 1 Register notice that goes out with this package for ,ey 2 comment comment on temporary changes in risk. Do we need b 3 more than what's in there today. Should we put something 4 in the general reg guide that deals with this? 5 As I said, we'll talk the specifics of how we 6 deal with AOTs when we get to the February subcommittee. 7 meeting. ) 1 CHAIRMAN SEALE: 8 So 10-3 for a half an hour 9 would also be acceptable? 10 MR. KING: Under this limit, yes. But when l l 11 you start going beyond five hours, for example -- 12 CHAIRMAN SEALE: 10-2 for a half an hour. 13 MR. KING: Oh, yes, yes. \2 14 MEMBER APOSTOLAKIS: That 10-3 per reactor year 15 means if you were in that configuration for the full year. 16 MR. KING: For a full year, right. 17 CHAIRMAN SEALE: Exactly. 18 MEMBER APOSTOLAKIS: I'll have to think about l 19 that. 20 MEMBER KRESS: Tom, on this temporary change 21 in risk, it seems to me that the quantitative health 22 objective, say, on early fatalities doesn't have any time 23 that's built into it. The one year is a convenience. 24 What we're really dealing with is a right at /~x k_,) 25 which accidents happen. And we multiply that right by a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE.. N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
162 1 year. We end up with a total, a number of deaths that are
-s 2 due to accidental means over a year. We use that, .1 G
3 percent of that, as our QHO. So what we're dealing with 4 is a rate. 5 Why can't that rate be used for any length of 6 time and derive a -- instead of 5 times 10~7, you end up 7 with the fraction of the time assuming the rate were 8 constant over a year and end up with the same QHO and 9 apply it on any time increment that you wish to? It seems 10 to me like it would be perfectly compatible with the QHO 11 and be consistent and -- 12 MR. KING: Whether express it in terms of per 13 year or per hour, as long as it's based upon the same
- )
'\ / 14 fundamental QHO number, what difference does it make? I 15 guess my question is: What would it buy you by doing 16 that?
17 MR. HOLAHAN: No. If I understood how you 18 constructed that, I think you probably can't live with it 19 because what you were saying is you would be applying to a 20 situation in which you knew it wouldn't last the same 21 standard that you would apply to situations that you think 22 persist most all the time. 23 I don't think we want to apply, for example, 24 to allowable outage times a standard that says, "While fx ( ,) 25 you're in the allowable outage time, you're meeting the NEAL R. GROSS
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I 163 1 QHO to the same extent as when you're not in the allowable ) f- 2 outage time." : (\ ' 3 MEMBER KRESS: I don't understand why not. 4 MR. HOLAHAN. Because you know that your 5 exposure to that situation isn't going to last. So why 6 should I act as though it will? , 7 MEMBER KRESS: Take, for example -- l 8 MR. HOLAHAN: It's an integral effect. l 9 MEMBER KRESS: Let's look, for example, at ) 1 10 shutdown. And let's say that you know that the 11 containment is going to be open for some fraction of that 12 shutdown period. That seems reasonable to me there to say 13 that, "I know my conditional containment failure ( 1 14 probability there is one for that time period that the 15 containment is open." 16 MR. HOLAHAN: We're encouraging licensees to 17 be able to close it. So maybe it's only -- 18 MEMBER KRESS: Maybe it's only .9 then or 19 something. But, anyway, a reasonable approach there might 20 be to decide what core damage frequency I could live with 21 -- 22 MR. HOLAHAN: Yes. i 23 MEMBER KRESS: -- and still meet the QHO with 24 a conditional containment failure criteria of one, where rn
) 25 the QHO now is for that time period only, and require that f i
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l 164 l 1 whatever they do maintains that core damage frequency. r3 2 MR. HOLAHAN: But the fact that you knew that, 3 let's say, the situation would only persist for five 4 percent of the time, would you consider that in the 5 calculation? 6 MEMBER KRESS: Yes. 1 7 MR. HOLAHAN: So, in effect, you're averaging l 8 the effect? 9 MEMBER KRESS: Yes. I 10 MR. HOLAHA7: Okay. Then I agree. l 11 MEMBER KRESS: Okay. ! 12 MR. HOLAHAN: And then I think that's more or ' l 13 less consistent with what we've suggested here. \ ( .g
\ '--) 14 VICE CHAIRMAN FOWERS: I guess I don't l
15 understand quite. I thought you were advocating a 16 position or suggesting a position where the accident rate ; i I 17 during the outage period was below some criteria similar 18 to the accident rate during power operations. 19 MEMBER KRESS: No, I don't I'm saying that. 20 I'm saying your acceptance criteria could still be derived 21 from the OHOs and that you have to think about the 22 difference between the fact that your containment may be 23 open and your initiating frequencies may be different. l l 24 You've got to do some things extra to protect yourself to l 25 maintain that same level of QHO. NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS I 1323 RHODE ISLAND AVE., N W. I (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
165 1 Maybe it's not the right way to go because 2 QHOs were intended for power operation and long-term. And (A V) 3 we do have a special situation. It was just a thought. 4 MR. HOLAHAN: But the same logic applies to 6 5 CDF or large early release except I'm not sure what early 6 means. But so long as you're saying that as part of this i 7 calculation you take into account the fact that you know 8 that this exposure is only, let's say, ten percent of the ! 9 time or five percent of the time and you average it out 10 over the long haul, I think that's okay and is more or 11 less consistent with what we're doing here. 12 VICE CHAIRMAN POWERS: I guess I just don't 13 understand at all. The QHO is defined. The quantitative V 14 OHO gives you a unit, which happens to be per year. And 15 you're saying because that unit was per year, we should l 16 amortize over a year? 17 MR. HOLAHAN: No. You should average over l i 18 time. It doesn't matter whether it's a year, but it has 19 to be a period of time you're averaging over that's larger 20 than the deviations that you're talking about. It has to l 21 be larger than allowable outage times or variations in l l l 22 start-ups and shutdowns. So it would probably have to be 23 averaged over at least months in order to smooth out the 24 variability. I But why do I want it -- (__,/ 25 VICE CHAIRMAN POWERS: NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234 4433 WASHINGTON. D C 20005-3701 (202) 234 4433
166 1 isn't it the variability that I don't want? I mean, I l
,o 2 don't want sharp peaks.
)
(O 3 MR. HOLAHAN: But you have to recognize that 4 some level of peaks is reality. All equipment can't be in 5 service all the time. We tell licensees to take it out 6 for maintenance. 7 VICE CHAIRMAN POWERS: But isn't there some 8 spike that's so big that I could find it intolerable? 9 MR. HOLAHAN: Well, the height of the spike 10 being intolerable, -- 11 VICE CHAIRMAN POWERS: Yes. l l 12 MR. HOLAHAN: -- regardless of its -- l 13 VICE CHAIRMAN POWERS: Regardless of its l C'\ 14 duration. 15 MR. HOLAHAN: I think there is. We haven't i 16 defined that. Even what we've talked about here is an ! 1 17 area under such a spike and not the height of such a j 18 spike. What Tom has suggested is some corresponding peak 19 that would go along with typical spikes. 20 In reality, I don't think it's a problem. I l 21 think when the spike gets higher than 10-3, other things l 22 cut off that spike. Defense-in-depth, tech specs, l ! 23 engineering margins don't allow 10'2 and 10-2 spikes. 24 We could write a criteria that says your spike
/\
U 25 shouldn't be higher than 10-2, but I don't think it would NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
167 1 ever come into effect. You have to realize that in order 2 to be in that situation, either you have to have an 7-~ J 3 initiating event going on or you're dealing with events 4 that are frequencies of 10-2 with no safety systems 5 available. It's not possible to get there. 6 MEMBER APOSTOLAKIS: I was thinking about, 7 Gary, in terms of real life now, what is it that makes you 8 tolerate these temporary configurations. And it seems to 9 me -- and that's consistent with what you said earlier 10 about placing value on prevention or on mitigation -- that 11 it's really the knowledge that the probability of having 12 an initiator is low. 13 MR. HOLAHAN Yes. /'%
-- 14 MEMBER APOSTOLAKIS: So perhaps at this level, 15 instead of trying to work with the total core damage 16 probability or core damage frequency per year and then try 17 to see what that means for shorter periods of time, 18 another approach might be to look at the initiators. And ;
19 those naturally, then, will put a bound. 20 I mean, that's just an idea that just occurred 21 to me. I haven't thought about all of its ramifications. 22 Because that is really what makes you say, "Well, gee, you 23 know, if it's only for a few hours, that's okay because my 24 LOCA frequency is this." l [~h () 25 MR. HOLAHAN: Right. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234 4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
168 1 MEMBER APOSTOLAKIS: "My" this is that. So I
<s 2 really don't expect to get in trouble. And that's V)
I 3 consistent with the defense-in-depth idea, as you said, 4 and so on. 5 But if, on the other hand, you see that the 6 probability of core damage frequency is high because the 7 probability of having an initiator has approached one, 8 then you probably don't tolerate that at all. Is that 9 correct, even though you have all the mitigating systems? 10 MR. HOLAHAN: Yes, yes. Of course. Yes. I 11 don't think we have any tech specs or any rules that 12 prevent it. In other words, there's nothing in the 13 plant's license that says that while it's having a LOCA
<,_ \
('--) 14 it's not allowed to use its tech spec and take equipment 15 out of service. Okay? I mean, the tech specs don't say 16 you can take a system out of service for seven days, but l 17 don't do it during a LOCA. 18 Well, everybody knows you shouldn't take it ) 19 out during a LOCA. 20 MEMBER APOSTOLAKIS: No. But I'm saying a 21 priori when you turn these numbers, you can take these 22 considerations into account and say, "Look at the I l 23 frequencies of the initiating events" and then use some 1 24 sort of argument based on those to come up with a limit. () 25 That's really what I'm saying, which is what you said NEAL R. GROSS COURT REPORTERS AND TRANSrRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C 20005-3701 (202) 234-4433
l 169 1 earlier. ("%, 2 MR. HOLAHAN: I think if you just think about l L that for a little while, we don't have initiators that are 3 4 much more than 10-2 5 MEMBER APOSTOLAKIS: That's right. 6 MR. HOLAHAN: Even loss of feedwater reactor 7 scrams is in the range of 10-2 8 MEMBER APOSTOLAKIS: Per year. 9 MR. HOLAHAN: Per year. 10 MEMBER APOSTOLAKIS: Per year. 11 MR. HOLAHAN: Per year. And so in order to 12 have a spike, a 10~2 spike, you would have to have no heat 13 removal capability so that every reactor scram was a core 7_
/ 4
14 melt. Okay? Well, we already have technical l
15 specifications that shut plants down when they don't have ! 16 that level. 17 And if I think you went and tested, well, is , l 18 it possible to get yourself into a 10 2 configuration, I 19 think you'll find that it's not possible either. Now, if 20 we write an additional guideline that does that, I don't 21 think it accomplishes anything. 22 MEMBER APOSTOLAKIS: I'm just saying it's part 23 of your argument. You may want ) think in terms of . l l 24 initiators, primarily initiators, on the total. 25 MR. BOB JONES: As part of the traditional NEAL R. GROSS , COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433 , 1
170 i 1 review of the tech specs, one of the things we do do is we r~3 2 look at: Say, for these AOTs, what is the rema:ning ( 1 N,_/ 3 capability? And what are the events that they need to 4 respond to? 5 So, for example, we did issue an AOT change 6 for South Texas on its diesels. And it turned out that 7 when you had multiple diesels allowed out, there was a 8 circumstance identified where, in fact, you wouldn't l 9 necessarily meet the safety analysis criteria. But it 10 talked A, B, C, D, and E to happen. 11 And so we said, looking at the initiator 12 frequency, looking at the probability, it is in the right 13 location at the right time. Looking at it also required a ! p_ (~' 14 loss of off-site power. We thought that in that interim 15 period that was okay, that you would be restricted by 16 time. 17 So I think the guidance does it as part of its 18 traditional deterministic review of the tech specs and 19 what capability still remains during the AOT. And it will 20 be factored into the decision-making that way. 21 But it is in the guidance already a ag those 22 lines, not as a specific look at frequency, but more a 23 look at what the capabilities are and what the events 24 you're trying to mitigate are, and factor that into your 25 overall decision. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
l 171 1 MEMBER APOSTOLAKIS: We'11 discuss this in gs 2 more detail. ! )
'O 3 Can you wrap it up in a minute? .
4 MR. KING: Yes. ) 5 MEMBER APOSTOLAKIS: What's the important l l 6 message that's on 15 and 16? 7 (Slide) i 8 MR. KING: The important message on 15 is yes, l 9 we have had some feedback from the pilots that have 10 affected the reg guide and vice versa. I think due to the 11 evolving nature of the reg guides and SRPs, there's more 12 of that to come. And wc can talk more about that in i 13 February, l
,n j i
b') 14 MEMBER APOSTOLAKIS: Sure. Yes. The expert 15 panel really -- 16 MR. KING: Yes. 17 (Slide) 18 MR. KING: Here's the expert panel. I just 19 wanted to point out where they're covered and what the 20 purpose of each is as we have them laid out. 21 MEMBER APOSTOLAKIS: Okay. I understand NEI 22 has requested time. So maybe this is a good time for them 23 to make a presentation. 24 MR. PIETRANGELO: Good morning. ( ()) 25 MEMBER APOSTOLAKIS: Good morning. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N 5N. (202) 234 4433 WASHINGTON D.C. 20005-3701 (202) 234-4433
172 1 (Slide) l
,s 2 MR. PIETRANGELO: I appreciate the opportunity
( ) l %J 3 to come and chat with the ACRS once again. It's been 4 quite some time; in particular, on this issue, the PRA 5 implementation plan. 6 We've kind of been laying back for a while. 7 We've been attending a lot of the ACRS meetings. We 8 haven't seen with one small exception much of what the 9 staff's been working on lately. We've just been 10 observing. But it's been a long time, and we thought 11 maybe this was a good time to provide some of our 12 observations. 13 We've had a risk-based applications task force
'/ 14 in place for about two years now. We meet on a regular 15 basis, about every three months. They include all the 16 owners' group chairmen who run the owners' groups' 17 activities on PSA applications. And we talk all the time 18 about what's been going on.
19 Quite frankly, we have some concerns I think 20 based on what we've seen on how the process is going and 21 the direction of it that we wanted to get some input in 22 now. And, of course, we will be developing comments on 23 all of the documents when they come out. But I think it's ! 24 an opportunity to give you our perspective on what we were l q)
's ,
25 trying to do with the PSA tool and how we intend to use it NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C 20005-3701 (202) 234-4433
173 1 and hopefully how that complements what t.1e staff is gs 2 trying to do with the PRA implementation plan.
\
Vl 3 (Slide) 4 MR. PIETRANGELO: Let's take a ste back 5 first. These are kind of the first principles that we 6 established for using PSA to improve our operations. 7 First of all, the whole point of this is to 8 improve our focus and attention on what's important. And 9 if you lose that perspective, it leads you to one of the 10 other bullets down here below that you can outweigh the 11 benefits with getting lost in the details of actually 12 applying this tool. 13 I think in a lot of the discussions we've 7.. ('- ') 14 heard over the last several months, it appears to us that 15 the tool's being taken out of context like it's going to I 16 be the basis. And, quite frankly, I think we've 1 l 17 contributed to that to some extent by using the term l l 18 " risk-based" in our documents and discussions. Probably 19 the staff had it more accurate with " risk-informed." 20 I think your consultant at your subcommittee, 21 George, talked about there are, in fact, no risk-informed i 1 22 regulations. This is really changing guidance and l l 23 interpretations of the existing regulations. There are no ' 24 proposed changes to the regulations at this time that are jm
?
(_,/ 25 risk-based or risk-informed. NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433 l
174 1 So the point here is that PSA is one
,esg 2 additional input into the decici.on-making process, It's l C/
3 not the sole basis for the decisions. And the PSA tool ! 4 should complement all our other tools in our 5 decision-making process. 6 The staff had a chart, not in today's 7 presentation, but in one of their previous ones, that 8 showed the process of defining the change and the 9 licens.ng basis, doino the analysis. And then you had the 10 deterministic and the PRA part up above. 11 Well, the only thing different is the PRA part i 12 up above. The other change process has been there for 13 about 25 years. Okay? And we're getting one additional
]
i 14 insight into that process. And it seems like we're 15 getting exercised pretty well over this additional insight 16 and at the same time keeping all of these other things and 17 trying to define those in greater detail. 18 I think probably in our perspective the RRG 19 had it right a couple of years ago. You have to go all 20 the way back and say, "How can we improve what we've been 21 doing over the last 20 or 30 years? Look at our event 22 experience. Look at our operational data." And PRA is 23 cne way to put all of that together. I i 24 But, rather than say, "The focus is on PRA,"
/
l (_j3 25 really, the focus is on regulatory improvements based on l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234 4433
175 1 our experience. 2 MEMBER APOSTOLAKIS: Do you think that the ("]) (_ 3 staff is placing undue emphasis on the PRA? l 4 MR. PIETRANGELO: I think so. I think so. 5 And the only part that we've seen -- and I should caveat 6 my whole presentation by saying we have seen almost 7 nothing of what the staff has been working on. The only 8 thing we have seen was the sum draft of the standard 9 review plan that was in the public document. 10 MEMBER APOSTOLAKIS: Let me understand that 11 better. Why? Can you be more specific? I mean, you have 12 seen their viewgraphs. Where is it that they are p- 13 overdoing it? ('_) 14 MR. PIETRANGELO: Well, I think that when you 15 look at even today's discussion, this morning, all this 16 focus on the numbers, we know -- 17 MEMBER APOSTOLAKIS: But you guys did that, 18 too. 19 MR. PIETRANGELO: We did it to some extent, 20 but we're not the NRC. 21 MEMBER APOSTOLAKIS: Well, I'll tell you, 22 though, what the problem is. It's not undue emphasis on l l 23 PRA. And I think the proposed Appendix S for fire 24 protection is a good example of this. What the staff is k_s/ 25 doing is saying: If you are to use probabilities, somehow I ! NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005 3701 (202) 234-4433 1
176 1 the licensee and we ought to know what to do with them. <- 2 And the major criticism of the proposed (3 w/ t 3 Appendix S was that you guys put some probabilities, 4 allowed some probabilities, to calculations in the 5 appendix and you didn't tell us what to do with them. 6 So I don't see that as a new emphasis. I see 7 it as a necessary element of the whole process that if you o allow someone to do a probablistic analysis, then somehow 9 I have to have some idea of what to do with these numbers. 10 And I think that's the whole problem that these guys are 11 struggling with. 12 And, in fact, I think they are pretty general. 13 I mean, all they're stating is principles. And then '- # 14 they're saying: Well, when you get the numbers, do 15 something with them. 16 MR. PIFTRANGELO: What you want to do with the 17 input you get from the insights that you get are focus ic your resources and attention better. 19 MEMBER APOSTOLAKIS: That's correct. 20 MR. PIETRANGELO: Okay. 21 MEMBER APOSTOLAKIS: That's correct. 22 MR. PIETRANGELO: And I think what we've been 23 seeing is a focus more on the process of using PSA. 24 MEMBER CATTON: But you need both, don't you? A ( ,) 25 MEMBER APOSTOLAKIS: Yes. I don't understand l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
I 177 ) 1 1 what "better" means in the abstract. I mean, if this was l l rS 2 between two guys, I would say it's okay. If Gary and Tony ( i
%-) But we're talking 3 were doing it, they can work it out.
4 about a lot of people getting involved. 5 MR. PIETRANGELO: I understand. ! l 6 MEMBER APOSTOLAKIS: You know, you have to l l 7 have some guidance. I 8 MR. PIETRANGELO: Right, right. Let me move 9 on. I think some of these points will become clearer as I l 1 10 go on. l 11 MEMBER APOSTOLAKIS: Okay. 12 MR. PIETRANGELO: Again, the other first 13 principle I wanted to talk about is -- and we have some t
\' 14 other bullets to address this later -- the benefits 15 clearly have to outweigh the burden of using this 16 technology or no one is going to use it.
17 And, finally, we understand PSA has 18 limitations. It has warts. In fact, it's a tool one can 19 pick on to no end. And some of the discussions in here I 20 think have picked on different aspects of PSA, some of its 21 weaknesses. And those have to be recognized. 22 I think the way we're trying to use the tool 23 is not to push the technology too far too fast and take ( 24 those coarse insights that we get and make some decisions 'A ( ,) 25 and move on. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
178 1 Move to the next slide. 2 (Slide) C/ You know, we have seen 3 MR. PIETRANGELO: 4 progress on a lot of the technical issues that have come 5 up. And I think we're getting there in that area. But, 6 again, I think the main point we wanted to make today was 7 that the assumption has been made that a licensee is going 8 to have to make some submittal to do anything with his PRA 9 in the future and regulatory applications. And I don't 10 think that's true. I don't think that's true. I 11 We can already make changes to our design. We 12 can already make changes to our licensing basis under the
,_s 13 current 50.59 process.
/ ) 4
~' Two other examples, the maintenance rule 14 15 implementation and Appendix J, Option B, did not require 1
16 any submittal to the staff for review and approval. And 17 as long as the 50.59 process remains reasonable, I think a 18 lot of changes are going to be made to the licensing basis 19 and design of the plants with PRA. 20 Now, clearly the tech spec changes are going 21 to require staff review and approval. I don't think 22 there's any question about that. That's the law. But I l l 23 think on a lot of these other applications we have been 24 talking about, particularly in light of the process we
- O
() , 25 have seen being developed, if it's going to require a NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE , N W. I (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
179 1 licensee to submit a package in each case to take fg 2 advantage of the insights that the PRA provides to focus 3 attention and resources better, I think that process has 4 tremendous potential to get very bogged down in a lot of 5 the issues that have been talked about over the last 6 several months with the ACRS. 7 MEMBER APOSTOLAKIS: I don't understand the 8 complaint here or the disagreement because I think the 9 staff made it very clear, even today, that you don't have 10 to use this. You can request changes using other methods. 11 You don't have to use PSA. 12 MR. PIETRANGELO: Right.
,.s 13 MEMBER APOSTOLAKIS: And then one of the 14 principles that has been stated several times is that you 15 should do -- I can't find it; it's always in front of my 16 eyes except when I need it -- that you should do a PSA or 17 a probablistic analysis that is appropriate to the 18 problem. Now, wouldn't that satisfy you?
19 MR. PIETRANGELO: Things have changed over the 20 last year or two. Okay? Let's take tech specs, for 21 example. , 1 1 22 MEMBER APOSTOLAKIS: Okay. 1 I 23 MR. PIETRANGELO: Two owners' groups were 24 making changes to their tech specs years and years ago, l i (") (_,/ 25 probably eight to ten years ago, with some PSA insights to l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
180 ! 1 1 extend a lot of outage times. 1 l , l g3 2 The current pilot that the staff is reviewing ) N.) from a different owners' group is doing exactly the same 3 l 4 thing. And they're still waiting on their approval. It's l 5 a very, very simple change that they've put forth as an l l \ l 6 owners' group. And I think it's being used to decide how 7 PSA is going to be used in this kind of process. 8 I thought the purpose of the policy statement l l 1 9 would be to encourage the use of PSA in all regulatory 10 applications. I would think there would be an expectation 11 on the part of the staff that when a licensee submits a 12 tech spec amendment request, what does the PRA tell you
- 13 about that. particular change that you're requesting?
A lot of 14 That's kind of changed lately.
15 licensees from the feedback we're getting are being 16 encouraged not to put the PSA insight in with their 17 amendment request because the process will take longer. I 18 think that's wrong. 19 MEMBER APOSTOLAKIS: And you're right, but 20 that has nothing to do with the reg guides. 21 MEMBER MILLER: Why is the process taking 22 longer? l 23 MEMBER APOSTOLAKIS: For the reviews. l l j 24 MR. PIETRANGELO: Because of the reviews. And i l (O _,/ 25 that's where my concern comes today, that the review NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433 I 1
181 1 process when you use PSA is getting fairly burdensome. f~x 2 And it has the potential to be more so once these ! I v 3 regulatory guides are promulgated. 4 MEMBER MILLER: Why is the review process 5 longer now than it would have been five years ago? 6 MR. PIETRANGELO: Because if you use PSA, it 7 requires additional staff review. 8 MEMBER MILLER: There's a limited number of 9 staff that are able to do the reviews. So it's kind of a 10 bottleneck or -- 11 MEMBER APOSTOLAKIS: Yes. No, I don't think 12 he's saying that it is more burdensome now compared to 13 five years ago. He's saying that because you are using 14 PSA, it requires an additional level of review. Evidently 15 they're overwhelmed and that takes a long time. 16 MR. PIETRANGELO: Well, whatever, but the 17 point is -- 18 MEMBER APOSTOLAKIS: But this has nothing to 19 do with -- 20 MEMBER MILLER: No, no. , i 21 MR. PIETRANGELO: -- that we were trying to 22 make it complement, rather than supplement. Okay? And if 23 it takes longer for the licensee to get the request I 24 through because he uses PSA, that's not much of an l r~s (,/ 25 incentive to use PSA. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. l (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433 l I
1 182 ! 1 MEMBER CATTON: If it's so simple that you l fs s 2 don't have to use a PSA, why do you submit it with it? I l i U 3 mean, I'm missing something. If it's clear without it, l 4 why submit the PSA? This is supposed to be complementary. 5 It's supposed to help you. 6 MR. PIETRANGELO: Right, right. Well, I think 7 that's the potential endpoint you'll get to is no one will 8 submit it. ll 9 MEMBER CATTON: But if they don't have to, 1 10 they shouldn't. If you don't need it, don't use it. 11 MR. PIETRANGELO: But that's not consistent l l 12 with the policy statement. ' 13 MEMBER APOSTOLAKIS: Well, the point is,
/'Tl l i \> 14 though, that we should recognize realistically that these 15 things don't happen overnight and that you're introducing 16 a new way of doing business. Naturally it's going to take 17 a little longer.
18 MR. PIETRANGELO: No, no. It's not that new a 19 way of being -- that's the whole point. This is not that 20 new. We have been using PSA for a long, long time. It is 21 one additional input. It is not a revolutionary change 22 and a whole new way of doing business. It's an additional 23 insight into this process. That's the point. 24 And we're focusing heavily on the process used b) (_j 25 to develop this additional insight. And there has to be , I NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W, (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 2'A-4433
183 1 some balance there between taking the insight and using it rw 2 efficiently and effectively versus putting this entire 3 burden on the process to make sure that whatever insight 4 you get out of it can be complementary to the decision 5 you're trying to make. 6 And all we're saying is there has to be some 7 balance there. And it looks like this is very one-sided 8 at this point and heavily process-oriented. I mean, if 9 there's one message that I want to get across today, 10 that's the one. It's not a revolutionary change. It's 11 evolutionary -- i 1 12 MEMBER APOSTOLAKIS: It was never -- l 13 MR. PIETRANGELO: -- with one additional
'b) 14 input. And it has to be a balance between using the 15 insight and focusing on the process. I 16 MEMBER APOSTOLAKIS: Well, again, it seems to 17 me if somebody says -- first of all, it is revolutionary, 18 with a small "r," as we have said many times. The diagram 19 that you described earlier really is something that you 20 have been using for a long time. All they did is add this 21 extra PRA thing there. So that's acceptable. That's 22 nice. It's not a revolution.
l l 23 MR. PIETRANGELO: Right. 24 MEMBER APOSTOLAKIS: Then they're saying, "Do
/m
) 25 an analysis that's appropriate to the problem." It seems NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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184 1 to me that's a reasonable statement. It's not burdensome. 73 2 MEMBER CATTON: Not yet. G 1 V 3 MEMBER APOSTOLAKIS: They can't say, "Do an 4 analysis that's inappropriate." 5 MEMBER MILLER: What I'm hearing is if you do 6 an analysis that's appropriate and has PRA in it, then it 7 requires an added level of review. Is that what I'm 8 hearing? 9 MR. PIETRANGELO: No. That was just an 10 example of the opposite effect that we want. 11 MEMBER MILLER: Well, I understand that. l 12 MR. PIETRANGELO: That's all that is. 13 MEMBER MILLER: What you want is you want to ( n i
'- 14 do as has always been done except now use PRA to maybe 1
15 adjust your approach, you probably want to do it under 16 50.59. ! l 17 MR. PIETRANGELO: Back up one second. The 18 pilots are necessary to establish what's the right thing 19 to do, what's acceptable in some of these applications. l 20 Okay? 21 If an additional, either on a station basis or 22 a unit basis, another 70 to 100 submittals have to be made { 23 to the NRC to move that process forward, I don't think l 24 that's an effective way to carry out risk-informed A
- (,,) 25 regulation. Okay?
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. ( l (202) 234-4433 WASHINGTON. D C. 20005 4701 (202) 234-4433 l
1 185 l l ( 1 If the pilots establish a method that's l l
,r 's 2 acceptable to the staff and the licensee can move forward, i L ,I 3 then, with that guidance and iuplement the change and then i 4 use the regulatory oversight through the inspection i
l 5 process and the documentation that the staff has available
]
6 at the site, that the licensee has available at the site, 7 then maybe that's a more efficient way of doing this. But l l l 8 to suggest that there's going to be a submittal on every 9 one of these things outside of tech specs, of course, I 10 think that assumption may be wrong. 11 And I think if we do have to go, if it's a 1 12 right assumption, if it's a correct assumption, I don't 13 think this process is going to go very far. Staff doesn't 7s
'~ have the resources to deal with 70 to 100 submittals on a 14 15 risk-based IST or ISI or QA or any of those. But that's 1
16 what that process says, " Submit this at the end." 17 I would think that the Commission can make a 18 policy-level decision on the way to do this one time and 19 not have to have 70 SERs signed out for a licensee to move 20 forward with this. 21 And that's one of our concerns, that we're not 22 in this so that a couple of licensees who have made a 23 significant investment in PSA can get the changes through. 24 We're in it for the whole industry to move forward. All
/
(_)N 25 right? And the process has to be practical for that to ( NEAL R. GROSS I COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234 4433 WASHINGTON. O C. 20005-3701 (202) 234-4433 L
186 1 happen or a lot of the work that the staff's done in the f-~s 2 past year will go for naught. 3 MEMBER CATTON: What you're saying is that you 4 can't come in and request one of these changes by 5 reference to another plant that's done so? 6 MR. PIETRANGELO: I'm saying that there may be 7 a way to do this without having to come in. Appendix J, 8 Option B was implemented that way. The maintenance rule 9 did not have a submittal involved with it. 10 We can do changes already under 50.59 without 11 prior staff review and approval; in fact, ones that had 12 small increases in risk, been done for years. All this 13 tool is giving us is another way to answer some of these A> e
\-' 14 questions. I 15 But does the process have to change and go 16 through a big submittal process now that we've got a tool 17 that can focus us a little bit better? Do we have to do 18 things completely differently than the way we were doing 19 them before? I don't think so.
20 MEMBER APOSTOLAKIS: Is there a place where 21 you have these things in writing so I can understand them i 1 22 better? 23 MR. PIETRANGELO: We will put them in writing 24 when we put our comments in the reg guides. Again, the
,- m k_,) 25 big caveat is we have not seen outside of an unknown l NEAL R. GROSS
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i 187 l l l 1 I l 1 revision to the standard review plan that was in the PDR l t
,ew 2 what the staff has been working on. We have been ,
(_) 3 following along in the ACRS meeting. l 4 MEMBER APOSTOLAKIS: But I must say that it 5 seems to me that there is a fundamental problem with the 6 interpretation of the word " insight." You're saying PRA 7 gives us additional " insights." And you seem to assume , l 8 that everybody understands what that meant or how it will 9 be used. l 10 MR. PIETRANGELO: I'll give you a better 11 example. If you look at some of the questions that the 12 pilots have been getting on some of the things --
,s 13 MEMBER CATTON: We haven't seen that. \] 14 MEMBER APOSTOLAKIS: The pilots? Not yet.
15 VICE CHAIRMAN POWERS: No. , 16 MEMBER CATTON: So maybe we'll be more 17 sensitive to his concerns when we do. : l 18 MEMBER APOSTOLAKIS: All I'm doing is I'm i 19 trying to understand what he's saying. 20 MR. PIETRANGELO: Right. ) 21 MEMBER APOSTOLAKIS: I'm not attacking it. , l 1 22 But I would like you to be here in February to -- I would 23 like you. It would be nice for you to be here when we 1 24 have the subcommittee meeting. j l (~h l (,) 25 MR. PIETRANGELO: Yes. And we do plan to l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS i 1323 RHODE ISLAND AVE., N W. 4 (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 2344433 l
188 1 come. But I think we want to come back and talk about , l
,s 2 some specific things. This is more of a broader, general
( N/
) I 3 --
4 MEMBER APOSTOLAKIS: Sure, yes. 5 MR. PIETRANGELO: -- policy discussion. 6 MEMBER APOSTOL4KIS: Yes. An example is a lot 7 of these applications involve ranking. Okay? And we can 8 spend an awful lot of time trying to split hairs on which 9 SSCs are risk-significant and which SSCs are 10 non-risk-significant or we can kind of make a coarse cut 11 and say we know these for sure are risk-significant and we I? know this other group is non-risk-significant. And we 13 have this middle. Over time I think the middle will (n}
shrink as our methods get better, as the data gets better, 14 15 as the quality of the PRAs get better.
16 We can't establish all of that in one fell 17 swoop up front, but we should be able to take the course 18 insights and get on with the application. 19 MEMBER MILLER: Does that mean those in the 20 middle, then, will keep the high risk-significant until we 21 -- 22 MR. PIETRANGELO: I think they will probably 23 keep their current treatment, whatever it is. 24 MEMBER MILLER: So if they're Appendix B, ex l \ (_,/ 25 we'll -- NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
189 1 MR. PIETRANGELO: Right. rx \ 2 MEMBER MILLER: -- keep them that way? If i %J 3 they're not, we won't? 4 MR. PIETRANGELO: Yes. And I think it's, 5 again, trying to get it to be more evolutionary and 6 incremental, rather than trying to make some huge step 7 that no one can swallow up front. 8 MEMBER APOSTOLAKIS: But why would the present l 9 approach or the proposed approach prohibit that or inhibit l 10 that? 11 MR. PIETRANGELO: Well, I guess I'm seeing in 12 the slides with the reg guides the key elements, the 13 risk-monitoring program, the performance monitoring.
\' 14 Clearly the licensees are going to have a responsibility 15 for establishing the qualit y through peer review or i
16 independent review, 17 But in the submittal process, I mean, you 18 referred to it as the license to kill. By the time you 19 get through all of the deterministic considerations and 20 trying to prove that your PRA was good enough and that it j 21 was used effectively, I think that detracts your attention 22 and resources from getting the insight, the incremental 23 insight, and moving forward with the application. I 24 And we need the experience with and from the
.r
(,h) 25 applications to evolve. We can't evolve without doing it. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
I 190 1 There haven't been any done. I mean, we were making more ,'~g , 2 progress two years ago than we are now, basically stopped V I 3 while we're waiting for all of these reg guides and SRPs 4 to be developed. l 5 And that was not the staff's intent I don't ! 6 think 18 months ago. When we published the PSA 7 applications guide, the message we got was: Well, let's 1 8 use it in applications and see how it works, and we'll 9 learn from that. 10 Well, that hasn't happened. That has not 11 happened. Licensees are using them for non-regulatory 12 applications. And so I think the process has been stalled 13 somewhat. We're not evolving. We're waiting for some 7s i) 14 thing to be developed here. And our concern is that it's 15 not going to serve our needs particularly well, the 16 industry's needs. 17 MEMBER APOSTOLAKIS: I guess I don't 18 understand what you're saying there, Tony, because, again, i 19 if I take the example you gave with the ranking and I go 20 back to what these guys are doing, it seems to me that l 21 they allow me to do a PRA depending on what I want to do. l 22 I may do a point estimate if I'm not very 23 close to the goal and use an importance measure to rank 24 and then go to my expert panel and have the expert panel (_ / 25 review that and be a little bit on the conservative side, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 234-4433
191 1 include a little more and provide an argument that these 7- 2 are the important SSCs. N-]3 3 And there is nothing that I've heard from the 4 staff that says that this process has to be too elaborate 5 or submitting. I mean, all they're saying is: Now having 6 done that, if you want to propose some changes, do an 7 analysis that's appropriate. And then when you get your 1 8 numbers, here is some guidance how to handle those i 1 9 numbers. So I am having difficulty understanding why you 10 are so negative. But maybe I don't understand your 1 11 position. 12 Now, the other thing is I sense that you are 13 bringing into this things that are happening in real life (,_)
*' 14 right now which are frustrating to you, like when somebody 15 tells you, " Don't put any PRA in it because it will take 16 forever to review it." l I
17 And I understand that, but at the same time 18 this is not part of the reg guide that these guys are 19 preparing. 20 MR. PIETRANGELO: I think if the process 21 includes an NRC review and approval of every regulatory 22 application. I don't know how long the process will take 23 for this. I can guess at what it takes based on my 24 experience. And you've heard presentations from other t' k ,/ 25 people about the incentives for doing this versus not NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISt.AND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433 i
192 1 doing it. Okay? s 2 For the licensee, if the process is very 3 burdensome and extensive, they won't do it. 4 MEMBER APOSTOLAKIS: I'll have to understand 5 that a little better, but let's go on. 6 MR. PIETRANGELO: Okay. 7 MEMBER MILLER: Yes. I think let's listen l 8 because it may just flag us to ask the right questions as 9 we go through these -- 10 MEMBER APOSTOLAKIS: Yes, yes. I fully agree. 11 All I'm saying is that I don't quite understand what the 12 difference is at this point. But I will at some point. 13 MR. PIETRANGELO: The other caveat or caution ?(
\ 14 I wanted to raise was this whole talk about the numbers.
l 15 You cannot do PRA without using the numbers. Okay? But I 16 would be very, very cautious about any perception of 17 regulation by numbers. 3 18 Again, it's one thing for the industry to put l l 19 in an industry guideline numbers for risk increases and so l 20 forth. It's a different thing for the NRC. We didn't ask , 21 the NRC to approve our PSA applications guide. Okay? 22 There wasn't any regulatory requirement we were trying to 23 meet with that. 24 Your whole discussion this morning about rules O) (, 25 and reg guides and such is appropriate because normally a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
193 i l 1 regulatory guide is developed for implementation of a l 2 rule. Okay? And Gary was absolutely right about legal 7e~3 1 GI 3 standing and all of that stuff. 4 Once you start putting it in things like i 5 regulatory guides that are normally used for i 6 implementation of a rule, I think it will be an 7 interesting legal analysis that comes out of that. 8 MEMBER APOSTOLAKIS: No. But this is -- 1 9 MEMBER CATTON: You have a rule to go along 10 with it, j l 11 MEMBER APOSTOLAKIS: This is really something l l 12 that we have discussed with the staff several times. And
,s ,_ 13 they have been very responsive to comments from this 1 4 \
14 Committee. , i l 15 The issue of the bright lines that Bob l l 16 mentioned earlier, I mean, they agreed to remove those 17 figures from the guide because they give the wrong l 18 impression. And then you have not seen this, but they do j 19 discuss in detail the issue of compliance. So they do I 20 acknowledge that these numbers are not to be used as go/no I 21 go criteria. So maybe that will satisfy. l 22 MR. PIETRANGELO: No, it doesn't because -- 23 MEMBER APOSTOLAKIS: It doesn't? 24 MR. PIETRANGELO: No because every time I've
/~T
- (_,) 25 come to one of these meetings, you talk about them like i
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
194 1 they're acceptance guidelines or decision criteria. It's
2 taking the tool, again insight, out of context and saying J
3 PSA is going to be the number that drives this decision. 4 Even we -- and we don't have the same problems 5 the NRC has in terms of being a federal agency -- call 6 them screening criteria. 7 MEMBER APOSTOLAKIS: Right. 8 MR. PIETRANGELO: We didn't call them decision 9 criteria. And we made that point several times. Yet, l 10 they're always called the same things. And it's almost And somebody has ! 11 like it's the basis for the decision. 12 got to sign on the dotted line based on a number. That's 13 just not the case. O V 14 MEMBER APOSTOLAKIS: You are bringing up 15 another issue now. You are saying now, no matter what the 16 guide says, people are going to use those as means of 17 acceptance criteria, go/no go. That's another issue. l 18 MR. PIETRANGELO: Regulatory guides are used 19 like rules today. 20 MEMBER APOSTOLAKIS: But if it says there in 21 three pages that you should not do that and that you 22 should take into account uncertainties and all of that, I 23 don't know what else they can do except completely remove l 24 that, which again brings me back to Appendix S, which to i m, 25 me was unacceptable. Just to say, "Do a probability i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
i 195 1 analysis" and then somehow make a decision it seems to me ('g 2 is not acceptable either. l Q_,) l 3 So somehow we have to have the golden mean, 4 the golden place where we are not describing criteria that 1 5 are go/no go so they tie your hands. On the other hand, 6 we are not just saying this is a supplementary tool, 7 augment, a tool that augments the analysis, uses insights, 8 and leave it at that because I don't know what insights 9 means. And I think you're going to have a mess on your 10 hands if you leave it at that. 11 MR. PIETRANGELO: Okay. I'm going to skip 12 ahead to the conclusions because I think I've gone through 13 every observation already. 7s U 14 (Slide) 15 MR. PIETRANGELO: Obviously industry has 16 invested a significant amount in PSA. And we want to get l 17 a return on that investment. That means safety 18 improvements as well as improvemente in efficiency in the i 19 regulatory process. No question about that. 20 It's in our interest and I think the staff's 21 to try to maintain some momentum with this process. And I 22 think it's slipping away, if not stopped. The process is 23 really stopped. t l 24 We've already done -- we talk about in the reg i 25 guide the change in tone, say, "Yes. We're going to use i NEAL R. GROSS l j COURT REPORTERS AND TRANSCRIBERS I 1323 RHODE ISLAND AVE , N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
196 1 it for improvements in safety," recognize that the first 2 use of the IPE was to identify vulnerabilities and address 7x (w- ) 3 those and accident management insights. I mean, we have 4 been using them for safety since they have been developed. 5 And that's kind of been lost in this process. 6 We do expect that, given what's been developed l 7 in response to the generic letter, that we should have ! 8 some expectation for improvements in the regulatory 9 process. ; 1 10 (Slide) 11 MR. PIETRANGELO: Another point we've tried to 12 make is that this is going to be market-driven. Let's say l 13 you do have to make a submittal for each and every /'_ % 14 irnrovement in the regulatory process. 15 Again, if there's not a benefit that outweighs 16 the burden, people will not submit. And just based or. 17 what's happening in the past year or so, we have gotten I 18 think from three or four licensees news that they're 19 disbanding their PRA organizations. And that's not what 20 we wanted to happen here. 21 MEMBER FONTANA: And the primary reason for 22 that is what? You told us, but -- 23 MR. PIETRANGELO: For disbanding their 24 organizations? 7_s ( ,,) 25 MEMBER FONTANA: Yes. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 2344433
197 1 1 MR. PIETRANGELO: Well, I think they don't see 1 gm 2 any benefit to it. It's as simple as that.
~
3 MEMBER APOSTOLAKIS: I must say I'm a bit 4 surprised at how negative you are. And I personally feel 5 that I have to underst and your position much better before 6 I contribute to the letter this Committee will write in 7 March. So I would like to ask you what you think would be 1 8 the best mechanism for us to understand better your 9 positions because obviously at least I don't feel that I 10 fully understand them. 11 If possible, before the 20th of February so if 12 there are any questions that we need to raise -- because 13 this vill be the time to raise them to the staff because,
,q r '/-
14 in all fairness to them, they have to produce all of these < 15 documents. They have deadlines and so on. We can't hit 16 them at the last moment with questions. 17 So what do you think would be an appropriate 18 way for you to really let us know and argue your position 19 so that at least I would understand it better. 20 MR. PIETRANGELO: I think we can take that up 21 individually, George. I don't want to take the whole 22 Committee's time because, again, we have not seen all the 23 documents. They are draft documents. They have not gone l 24 through the public review process yet. And we will l l g)
\, 25 provide our comments at that time.
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198 1 CHAIRMAN SEALE: When will you get those m 2 documents? I i LJ 3 MR. PIETRANGELO: Sometime in May -- 4 MEMBER APOSTOLAKIS: Yes, but that's too late 5 for us. 6 CHAIRMAN SEALE: Yes. 7 MR. PIETRANGELO: -- is my understanding. 8 MEMBER APOSTOLAKIS: I don't know how this 9 thing works, but is it inappropriate for you to write a 10 letter to me or to the Chairman? 11 MR. PIETRANGELO: I think the process has a 12 long way to go yet. 13 MEMBER APOSTOLAKIS: But, I mean, there are l )
/ 14 obviously certain things that bother you right now.
15 MEMBER BARTON: To get the industry's 16 negativism that you're expressing before this Committee 17 before us before we writ a letter to the Commission 18 endorsing the process. 19 MEMBER APOSTOLAKIS: Send a letter, you know, 20 a page or two, and say, "These are my major concerns. i l 21 One, two, three, four." i 22 MR. PIETRANGELO: All right. 23 MEMBER APOSTOLAKIS: And then on February j 1 24 28th, we'll pick it up and see what -- we'll discuss it r% 25 with the staff. And you said that you will be here. So NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
199 1 we can have an open discussion. That's why it's a two-day r- 2 meeting. Plenty of time. i Y ]3 3 MR. PIETRANGELO: All we're asking for is thec 4 there ought to be an appropriate balance between the 5 process used to establish the PSA insight and actually 6 using the PSA insight to make improvements. 7 MEMBER APOSTOLAKIS: And I don't think anyone 8 disagrees with that, Tony. 9 MR. PIETRANGELO: Right. 10 MEMBER APOSTOLAKIS: But that's why I want to 11 have something more specific in my hands to understand 12 where the source of your frustration is. 13 MEMBER MILLER: Well, it seems like it's 14 almost like there's a lot of unknown. And, of course, as l 15 you do sit here, there is concentration on the, quote, 16 unquote, " process" because we're concentrating on a narrow 17 set of guidelines which are to be taken in the context of 18 a larger set of decisions. l I 19 I'm only thinking that Tony is reflecting kind 20 of the fear of the unknown. We don't know what's going to 21 happen yet. 22 MEMBER APOSTOLAKIS: Yes. 23 MEMBER MILLER: I'd be interested, for 24 example, to see why are utilities disbanding the PRA O k ,/ m 25 organizations. Is that the perception they have that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 234-4433
200 1 things are going to get worse or the fact that they have 2 gotten worse? L/ 3 CHAIRMAN SEALE: There are several other 4 interpretations of that, too. 5 MEMBER MILLER: They have to allocate 6 resources and they can't afford to have five people or 7 whatever it is to do that business. 8 CHAIRMAN SEALE: I guess I have to make 9 another observation. A workable way of doing it, a 10 reasonable assessment of the consequences of the PRA 11 analysis, those are certainly appropriate expectations on 12 everyone's part, f- 13 But there's also the problem of making charges
14 in the licensing basis for the people who apply for these 15 changes, which are successfully judged to not degrade the 16 health and safety of the public.
l 17 And I think that's a concern that the staff - 18 has. They want some, if you will, transparency that i 19 they're not giving away the store. And there are an awful 20 lot of people out there who are very concerned that this 21 process might give away the store. j 1 22 And so I think if you had any thoughts on that 23 part of the problem, too, it would be helpful to us 24 because everybody has to succeed before anyone can win in (3 (_ / 25 this effort. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
201' 1 MR. PIETRANGELO: Yes. If it's perceived as r~g 2 giving away the store, then we're all losers. < 4 V 3 CHAIRMAN SEALE: That's right. 4 MEMBER iPOSTOLAKIS: That's right. 5 MR. PIETRANGELO: There's no question about 6 that. But that's why I think I'm trying to be so strong 7 about not taking PSA out of context as making it the sole 8 basis because you'll get picked apart in the process if 9 you try to do that. 10 MEMBER APOSTOLAKIS: Now, I realize that you 11 don't have the actual draft guides, but I think the 12 viewgraphs you do have. If you decide to send us this 13 letter, -- and I would really urge you to do that -- I ; i \' ,) 14 would also like to see the list of your concerns but also 15 can you tell us specifically what you would like to see 16 removed from what they're doing? 17 MR. PIETRANGELO: Specifically, no. 18 MEMBER APOSTOLAKIS: But if you're saying that i 19 it's the sole basis for decision, I'm trying to understand 1 20 what that means because -- 21 MR. PIETRANGELO: That te'll never call any 22 chart or number that the staff uses acceptance guidelines 23 or decision criteria. Then I'll start thinking maybe it's 24 not the sole basis. b(_ ,/ 25 MEMBER APOSTOLAKIS: And I've got to repeat to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W, (202) 234-4433 WASHINGTON. O C. 20005-3701 (202) 134-4433
202 1 you that there are at least two pages of discussion in gg 2 that guide that say, " Don't do that. Don't do that. N 3 Don't do that." Okay? So maybe some of your concerns 4 will not be there after you see what they've written. I 5 don't know. 6 MR. PIETRANGELO: I think because of what Dr. 7 Seale said, this has to be looked at from a bigger picture 8 than just PSA. 9 MEMBER APOSTOLAKIS: There is no bigger 10 picture than PSA. 11 (Laughter.) 12 MEMBER SHACK: Unless it's thermal hydraulics. 13 MR. PIETRANGELO: I think the RRG charter is ( i 2 14 probably the right scope picture, which PSA was one 15 element of that, not just PSA. 16 MEMBER APOSTOLAKIS: Okay. Thank you very I l 17 much. l l 18 MEMBER CATTON: I don't think I've heard 19 anything that says that PSA is the sole -- 20 MEMBER APOSTOLAKIS: And that's why I'm trying 21 to ask him to put specific things in the letter. 22 MR. PIETRANGELO: Look in your slide package. 23 MEMBER APOSTOLAKIS: Okay. I will. 24 MR. PIETRANGELO: Look in your slide package. (Qj 25 MEMBER APOSTOLAKIS: And I would like you to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D.C. 20005 3701 (202) 234-4433
203 l 1 point me to the place where you feel they're overdoing it. ! I'm not disagreeing with you. I'm r-)
'n J 2 That's all I'm saying.
3 just saying -- ! 1 4 MR. PIETRANGELO: When you try to use absolute 5 numbers and put it in the context of acceptance,-- l 6 MEMBER APOSTOLAKIS: And I've got -- 7 MR. PIETRANGELO: -- that sounds to me like 8 sole basis. 1 9 MEMBER APOSTOLARIS: And I'm guaranteeing to l 10 you that these are not absolute numbers. I mean, we've 11 had hours of discussion with the staff -- 12 MR. PIETRANGELO: No risk increases for any l l 13 plant whose core damage frequency is above 10-4
/ T
14 MEMBER APOSTOLAKIS: That's not what the guide 15 says. That's what he said today, but that's not what the l
16 guide says. So I would really urge you to send us a note. 17 MR. PIETRANGELO: Okay. Thank you. I 18 MEMBER APOSTOLAKIS: Thank you for coming. It 19 was very interesting, Tony, very exciting. 20 And, Mr. Chairman, back to you. 21 CHAIRMAN SEALE: Gee, I'm sorry I missed all 22 of that. l 23 Okay. Let's see. Where are we? We are at l l 24 break time in every sense of the word. (_) 25 (Whereupon, the foregoing matter went off the i NEAL R. GROSS , f COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C- 20005-3701 (202) 234-4433
204 1 record at 10:35 a.m. and went back on the o 2 record at 10:49 a.m.) 3 CHAIRMAN SEALE: We'11 come back to order. 4 We're going to have a presentation on the AEOD spent fuel 5 pool study. Tom Kress, that's your subcommittee. So I'll 6 turn it over to you. 7 MEMBER KRESS: Thank you, Bob. 8 10) AEOD SPENT FUEL POOL STUDY 9 10.1) REMARKS BY THE SUBCOMMITTEE CHAIRMAN 10 MEMBER KRESS: As you'll recall, we heard 11 earlier from ONRR on a quick look they took at the risk 12 associated with loss of spent fuel pool cooling, but that 13 was a rather quick look. And I think the EDO asked AEOD f3 i I
'd 14 to take a more in-depth look at the. likelihood and 15 consequences associated with loss of spent fuel pool 16 cooling.
17 And we heard earlier about their plans for 18 doing this. And now that they have finished the study, 19 this is a briefing they're going to give us on the study 20 itself and the results and conclusions. 21 I think you have handouts in front of you 22 somewhere. 23 CHAIRMAN SEALE: Yes, right here. 24 MEMBER KRESS: Yes. I wish I could find mine. (3 b) 25 Here it is. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
205 1 So, Jack Rosenthal, did you want to say some I
g 2 words before --
(d 3 MR. ROSENTHAL: Well, thank you. ; I 4 10.2) BRIEFING BY AND DISCUSSIONS WITH l 5 REPRESENTATIVES OF THE OFFICE FOR ANALYSIS AND 1 6 EVALUATION OF OPERATION DATA ! l 7 MR. ROSENTHAL: Jack Rosenthal, Reactor 8 Analysis Branch at AEOD. i 9 Let me just say that the EDO asked AEOD to do l 10 an independent look of spent fuel pool cooling. We based 11 our look predominantly on the operating experience because l l 12 that's our forte. ! 13 We subsequently did the report. We
.s '- subsequently briefed the Commission on it; actually, Jose 14 15 Ibarra, the principal spokesman for the Commission.
I 16 Actually, Wednesday night, Jose Ibarra and Hal Ornstein of 17 RAB had the opportunity to speak at Waterford, Connecticut 18 to concerned citizens also about spent fuel pool cooling. 19 So, with that, why don't we hear from Jose. 20 (Slide) 21 MR. IBARRA: Good morning. My name is Jose 22 Ibarra, and I am from ACOD. 23 (Slide) l 24 MR. IBARRA: Like Jack said, it was about a
/^l (m-
\
25 year ago that the EDO requested that AEOD do an assessment NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234 4433 WASHINGTON, D C. 20005-3701 (202) 234-4433 l
206 1 of likelihood and consequences of losing spent fuel pool g 2 cooling. And we formed a team, and we did perform that ( )
%J 3 assessment. j 4 The first thing we had to do is deal with the I l
5 whole issue generically because, as you can imagine, there 6 are 109 plants. And there are about 74 different sites. 7 So we would be dealing with about 74 different 8 configurations. 9 So our first major task was to go ahead and 10 model a pressurized water reactor and boiling water 11 reactor. 12 Then the second major task was to assess 12 j 13 years. Actually, we assessed over 12 years of operational 7_ l 14 experience. This involved going over 700 pieces of 15 documents that describe operational events. ) 16 We also had the opportunity to visit six 17 sites. In these visits, what we wanted to do was to look 18 at the physical configuration of the pool. But also very 19 important to us was to understand the practices and 20 procedures that the licensees were using. We also 21 reviewed the regulations, reviewed the standard review 22 plan, and the applicable regulatory guides. 23 A very important aspect for us was to 24 understand what kind of power supplies were providing
,n
(_.) 25 power to the spent fuel pool. So we assessed that. We NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D.C. 20005-3701 (202) 234-4433
207 1 also were interested in what kind of parameters were being gS 2 monitored and where those parameters were being monitored. t
\_/
3 Heat loads were very important to us because 4 you could get to the point of boiling the water off in the 5 pool. And we also wanted to understand the kind of i 6 radiation levels you're going to encounter with the l 7 decreasing water level. 8 And then one of the final major tasks was to i 9 evaluate that risk. We contracted with Idaho National 10 Engineering Lab to assist us on that portion of it. I l 11 (Slide) 12 MR. IBARRA: This is a model for the 13 pressurized water reactor. What we essentially wanted to l [, T l
14 do was to capture the important components of a pool.
15 What we have in a pressurized water reactor is you have 16 the vessel in a different building than the pool itself. 17 And this can be very critical information. 18 The important portions here are you have the 19 reactor vessel, the way to transfer the fuel over to the 20 spent fuel pool. The fuel itself would be in racks. And 21 you have over 20 feet of water above that. 22 Typical parameters that are being monitored 23 are temperature level and radiation. You're cooling this 24 area now with the coolant system consisting of the pumps O (_) 25 and the heat exchangers. So these we feel were the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
208 1 important components of the spent fuel pools for a
<g 2 pressurized water reactor.
(v) 3 (Slide) 4 MR. IBARRA: Now, for a boiling water reactor, 5 we have basically the same components. But there are some 6 major differences, one of them being that now the reactor l l 7 vessel and the pool are in the same structure. You also l 8 have double gates, instead of single gates. 9 Now, when we're talking about variation in 1 10 configurations of the industry, some of the number of 11 pumps varies, some of the number of heat exchangers 12 varies, and also the dimensions of the pools vary. 13 (Slide) ! I
/~N s 14 MR. IBARRA: Like I mentioned before, we 15 evaluated about 700 documents. These are documents that 16 describe spent fuel pool activities and events.
17 We broke our assessment into two basic 18 categories, as you know. How can you lose cooling? You 19 can lose cooling by losing the inventory, and you can lose 20 cooling by losing the ability to cool. 21 What we mean by " loss of inventory" is: What 22 are the different ways you can lose the water? And you f 23 can lose it by the connected systems, the gates and seals, 24 the structure and liner. And, once again, these are the O) (_ 25 major items we had identified in our modeling. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, O C. 20005-3701 (202) 234-4433
209 1 For loss of cooling, you lose the ability to fs 2 cool if you lose the flow or you lose the heat sink. In V 3 looking at 12 years of operational data, we found 38 cases 4 where inventory was lost and 56 cases where cooling was 5 lost. 6 You have another important column here called 7 " Precursors." And these are events that could have led 8 you to the actual but never did. For instance, under 9 " Structure and Liner," we have 35. One of these is a 10 report to us that says that under elevated conditions, the 11 liner could buckle and could lead to loss of inventory. 12 (Slide) 7s 13 MR. IBARRA: This further breakdown of I
)
14 actually some of the details cf how you can lose the l l 15 water, what's important to us here is you can see that 16 most of the problems of losing water occur in 1 l 17 configuration control. And we found that to be human l i ' I 18 error. 19 Also, under " Load Drops," we find 32 cases of 20 scenarios where they actually moved heavy loads over fuel. 21 And that, of course, could cause some damage here and loss 22 cf water. 23 These, by the way, are tech spec violations. 24 CHAIRMAN SEALE: And in general involve human (- V 25 error. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
210 1 MR. IBARRA: Yes. It involved human error. (~N> 2 even though it's more obvious at this point. L.) 3 CHAIRMAN SEALE: Yes. 4 MEMBER KRESS: The events having to do with 5 the gates and the seals, is that improperly inflated seals 6 or improperly -- 7 MR. IBARRA: Some of those things, yes. In 8 fact, later on I'll mention some cases where inflatable 9 seals are the problem. 10 (Slide) 11 MR. IBARRA: We were able to get information 12 in other to be able to plot loss of inventory over how f3 13 many inches were lost. And what you see here is that I \ 14 there are 10 cases, 8 and 2, here where you do lose or 15 they lost over 12 inches of water. 16 MEMBER KRESS: What significance should we 17 ascribe to amount of level decrease? Is that an indicator 18 that somebody found it right away, the problem, and fixed 19 it or - - 20 MR. IBARRA: Well, we'll plot that also 21 because we'll find the duration in my next slide. l 22 MEMBER KRESS: Okay. 23 MR. IBARRA: It is important because you do 24 have 20 feet of water. And these would probably not cause
,y s- 25 problems. But when we're talking about ten feet of water, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
(202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
211 1 then you start encountering some problems here. Radiation
,w 2 levels, you have less time for the water to start boiling.
3 MEMBER KRESS: But these others, lower level 4 losses, could have gone on to that it somebody hadn't done 5 something. 6 MR. IBARRA: Correct, correct, correct. And 7 that's how come my next slide will put duration on there. 8 But talking about these two cases, one of them 9 was Hatch in '86. And that was an inflatable seal 10 problem. And then we have River Bend, a configuration 11 control problem in '87. 12 (Slide) 13 MR. IBARRA: Like you were saying, duration,
) \
14 of course, is important in how soon do you catch and 15 correct that problem. And here we were able to plot how 16 long they lasted before the problems were fixed. 17 Now, this to us is important, this eight 18 hours, because this is a point that water could begin to 19 boil. 20 And these two cases, we have Wolf Creek in 21 '87, a configuration control problem, and the inflatable 22 seal in Hatch in '86. ( 23 (Slide) 24 MR. IBARRA: This is just more details from (g_,) 25 the previous slides into what we mean by loss of cooling NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. ( i (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433 l
212 1 flow and loss of heat sink. To us important data that 7x 2 comes out of here is the loss of the pumps. We had 39 3 incidents of loss of pumps. And this is just loss of i 1 4 power to the pumps. 5 MEMBER BARTON: Is that all pumps or just one 6 redundant system? j 7 MR. IBARRA: Well, this is the ability to 8 cool. So it would be if they heated two, two would go 9 out. This means that you've lost the ability to cool. l 10 But, once again, we have to tie that with how long it took 11 them to correct the problem. 12 What we have with pumps is if you lose power, 13 your coolant is lost. You have to go manually and reload ( \ 14 those pumps to the buses. 15 MEMBER BARTON: So I've lost power to both 16 spent fuel pumps 39 times? 17 MR. IBARRA: That's right. That's what it 18 means. And having an extra pump is not going to help you 19 if you don't have power. 20 MEMBER BARTON: I understand that. I just 21 want to make sure you were losing power in both of them, 22 full system. 23 (Slide) 24 MR. IBARRA: And what we're doing here, just
/~N
(_) 25 like the loss of inventory, we're plotting number of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 234-4433
213 1 occurrences. And in this case we're plotting increase in ! io)
\_ ,/
2 temperature. 3 We have four cases here whose loss of coolant ;
)
4 resulted in an increase of about 20 degrees. And we have 5 one here that's 50 degrees, and that was Farley in '93. 6 Now, the pools normally run below 100 degrees. 7 Okay? So even at this case, it wouldn't present a 8 problem. What presents a problem is not capturing it and I 9 not fixing it.
- l 10 And we calculated that the frequency of l 11 loosing coolant that resulted in 20 degrees or more is .
l l 12 about 2 to 3 occurrences per 1,000 reactor years.
-s 13 (Slide) 14 MR. IBARRA: Now we're plotting duration. You 15 know, how long does it take to help this cooling?
16 MEMBER KRESS: Help me with the significance 17 of that particular number you just gave us. 18 MR. IBARRA: The significance is that 19 temperatures are increasing at a certain frequency. And 20 what we actually did was took the number of operating 21 years and divided by the actual increase in -- 22 MEMBER KRESS: I understand that, but this is 23 frequency of these loss of cooling events that led to a 24 temperature increase of? What did you say? t% (_,) 25 MR. IBARRA: Twenty degrees. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
214 1 MEMBER KRESS: Twenty degrees or more. ('s 2 MR. IBARRA: Right. NY 3 MEMBER KRESS: Now, is the significance of 4 that that if you get up to 20 degrees, then the likelihood 5 of stopping it before it went on to boiling is too low or 6 -- 7 MR. IBARRA: No. 8 MEMBER KRESS: How am I supposed to deal with 9 that number? 10 MR. IBARRA: It's just a gauge. 11 MEMBER KRESS: It's just a sort of a -- 12 MR. IBARRA: It's juat a gauge. Like I said,
- 13 you know, there is a lot of temperature -- it can tolerate
( )
14 a lot of increase in temperature.
l 15 MEMBER KRESS: Should I treat that number any 16 differently than one that's the frequency of getting up to 17 10 degrees or 15 degrees? Why is that a number that I can I ] 18 use to gauge the significance of these events? . l 19 MR. IBARRA: That was just a point that we j 20 took. There's no significance in there. 21 MEMBER KRESS: I can't interpret that number 22 in terms of potential for it to go on to CDF or something? 23 MR. IBARRA: Right. But we have to actually 24 look at the actual data that we're looking at. And we w_/ 25 know, like you said, that it doesn't cause problems here. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1523 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
215 1 Okay? But we are having 16 that fall into that category.
,'~'g 2 MEMBER KRESS: And the reason it didn't go any (V ;
3 higher is because somebody found the problem and fixed it? 4 MR. IBARRA: Correct. 5 MEMBER KRESS: So it's kind of a measure of 6 the ability to cover? 7 MR. IBARRA: It could be a measure of how 8 quickly. Yes, right. But the only thing of significance 9 here to me is the 50 degrees. That's a lot. I mean, they 10 should have been able to catch it before it got to t'at 11 point. 12 MEMBER CATTON: How long did it take to get to 13 that, one of these out on the end? In) 14 MEMBER BARTON: Greater than 24 hours. 15 MR. IBARRA: Yes. I would have to look that 16 up. That's Farley. That was an isolation, heat exchanger 17 isolation, problem that they had. I can -- Bill, can you 18 look that up? l 19 MEMBER CATTON: Did they know about it and 20 just took time to get it fixed or they just flat didn't 21 know? 22 MR. IBARRA: I think in this case they flat 23 didn't know. But I think we can find some of that 24 information. g, ( 25 MR. BILL JONES: My name is Bill Jones. I i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS , 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
216 1 work in AEOD. n 2 That event happened in 1993. And we have a
- V 4 3 listing for that as a duration of about three hours. They 4 isolated the cooling to the secondary heat exchangers for 5 preplanned maintenance, but there was an error. And they 6 lost cooling to the heat exchangers for about three hours.
7 Temperature risa went up somewhere around 130 to 140 8 degrees. 9 MR. IBARRA: That's the end temperature. 10 MR. BILL JONES: That is the end temperature. 11 That's not the -- 12 MR. IBARRA: Right. That's not the delta. 13 MEMBER CATTON: Well, delta is 50. 14 MR. IBARRA: The delta is 50; correct. 15 MEMBER CATTON: In three hours? 16 MR. IBARRA: Right. 17 MEMBER KRESS: Unless they had a full core 18 offload or something. 19 MEMBER CATTON: Fifteen degrees an hour. 20 MR. IBARRA: We'll get to that. 21 MR. BILL JONES: They'd been shut down about 22 11 days, and they did have a full core offload. That's 23 true. 24 MR. IBARRA: And we'll get to full core
'O,j \ 25 offloads because, of course, that's very important.
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433
217 1 Here what we had is three places where it took ,r-) 2 over 24 hours to correct the cooling problem. We had Q River Band, it was a 3 Haddam Neck. It was a pump failure. 4 configuration control problem; and Seabrook, configuration 5 control problem, 6 (Slide) 7 MR. IBARRA: Now, we did visit six plants. 8 That was North Anna, South Texas project, River Bend, TMI, 9 and Calvert Cliffs. And with that set of plants, that 10 includes all the reactor vendors, small and big 11 architect / engineers and included both single and shared 12 cools and all the big plants. So we feel that we did a
,_ 13 cross-section of the industry.
14 We did find a lot of good operating practices. l 15 I've listed some of these. Our report has more than this. 16 In one plant, they had a draindown. In fact, it was River 17 Bend. 18 And in the control room there now exists a 19 board in which they go ahead and lay out all of the valve 20 alignments. And that has helped them in trying to prevent 21 that kind of problem. And, like I mentioned before, 22 configuration control is the number one contributor. i I 23 We also found some plants were using risk ; 24 analysis in their outage planning. Some licensees are k_T) 25 using the classroom and simulator to prepare for the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
218 1 outage. 2 As far as the analysis is concerned, all the iq G licensees we visited had very good analysis, but not all 3 4 of them translated tnat to the operators so they could 5 easily see what was going on. Some did. And then some 6 had a very good program for looking at the industry and 7 looking at their own experience and feeding that back and 8 learning from it. 9 This plant was Susquehanna, where they had 10 almost ten years ago looked at all the different ways that 11 you could lose w&ter in the pool. And they had already 12 identified it. So they did it on their own long before 13 the spent fuel became an issue. /h \'") 14 MEMBER KRESS: How many plants did you visit? 15 MR. IBARRA: Six. 16 MR. ORNSTEIN: Six stations. It was actually 17 nine plants. 18 MR. IBARRA: Six sites, nine plants. And, 19 like Jack said, Wednesday we had the opportunity to go 20 through Millstone. It's interesting to find out that they 21 also had a draindown, Unit 1. And we go into the control 22 room. We find a chart, all alignment. So everybody has 23 had a problem with draindowns. And that's a very simple 24 thing. O h 25 MEMBER KRESS: What was your criteria for NEAL R. GROSS COURT REPORTERS AND TRANSCRIDERS 1323 RHODE ISLAND AVE., N W (202) 234 4433 WASHINGTON, D C. 20005-3701 (202) 234 4433
219 l l 1 deciding which plants to visit? l 2 MR. IBARRA: We just wanted to get a U('y 3 cross-section of plants, like I said. 4 MEMBER KRESS: A cross-section of types of 5 spent fuel pool designs or -- 6 MR. IBARRA: We wanted to make sure we covered 7 all the reactor vendors, -- 8 MEMBER KRESS: Reactor vendors. 9 MR. IBARRA: -- all the new plants, -- 10 MEMBER KRESS: I see. 11 MR. IBARRA: -- single and shared. We wanted j 12 to visit certain plants, and we weren't allowed to visit 13 them because of scheduling problems. But we picked other p_
'- 14 plants.
15 Other than just that criteria of making sure 16 it was a cross-section there was nothing. 17 MR. ORNSTEIN: Jose, would you want to say a 18 little bit more -- I'm Hal Ornstein, AEOD. 19 To elaborate a little bit more on what Jose 20 was talking about about the operator aids in the control 21 room, in the case of Millstone One, they had this drawing, 22 which they used grease pencil to indicate what the status 23 was. 24 And pr'ior to doing the actual manipulations, t'~ ( 25 they would go ahead. And several people would make sure NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C- 20005-3701 (202) 234-4433
220 1 that there were no interferences or conflicts to wind up /"N 2 with iluid pathways that would be a problem. 3 However, we observed in Millstone Two no such 4 situation. And the same was true for Millstone Three. It 5 appears that the utilities or the plants that had specific 6 problems were more sensitized to the issue and had 7 implemented aids of this nature. 8 MR. IBARRA: And we're talking about something 9 very simple, you know, just: What are the alignments? 1 10 And when there's a procedure or something going on that
\
11 changes that alignment, the operators go through it, ; 12 operator aids. gs 13 (Slide) (m,) 1 14 MR. IBARRA: We looked at the review plan, 15 standard review plan, in 10 CFR 50, Appendix A to the ] 16 General Design Criteria to find out what's applicable to 17 the spent fuel pools and also identified the regulatory 18 guides to the pool. 19 We wanted to do our own assessment on several 20 things to find out how things stand in the industry. And, 21 like I mentioned before about the power supplies to the 22 spent fuel pool pumps, we determined that about 80 percent ; 1 23 of the industry has safety-related power to the pumps. 24 Now, what's important is, of course, if it's n) s 25 safety-related, you have a high assurance that it's going i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005 3701 (202) 234-4433
221 l 1 to be there. But what's more important is for them to gx 2 have alternate ways to provide power in case you lose it. l \ ) , x_/ 3 Those pumps are load shed. And then you have to manually l 1 I 4 reload them. l 5 For instrumentation, we were interested in j j 6 finding out what parameters were being parameters and 7 where are those parameters being monitored. And they , 8 usually monitor temperature level, radiati$n, flow, and 9 leak detection. 10 What's important here is that a lot of these 11 parameters are grouped into one window in the control 12 room. So when it alarms, you actually have to send 13 somebody to a local panel to find out what was the cause I [~N
~'
14 of that alarm. Mainly temperature and levels are 15 sometimes differentiated and separated in the control J 16 room. I 17 We wanted to find out what kind of levels, 18 radiation levels, you're going to see when the water l i 19 decreases. And for this, we cctually got calculations 20 from the licensees themselves. We just compiled a bunch 21 of the calculations. 22 And, just to give you an example, at one foot 23 with a multiple bundle, you get about 900,000 R per hour. 24 And for a -- p ( ,) 25 MEMBER KRESS: Nine hundred thousand R? NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234 4433 WASHINGTON. D C. 20005-3701 (202) 234 4433
't 222 1 MR. IBARRA: Yes, extremely high. I mean, you r 2 wouldn't be able to go into the --
t ( 3 MEMBER KRESS: You couldn't have a fireman up ." 4 there pouring in water. 5 MR. IBARRA: Correct. That's right. 6 MR. ROSENTHAL: Excuse me. That's when 7 covered by one foot of water. So you've already boiled 8 down 19 feet. But the only point is to say that you'll l 9 have an uninhabitable environment in the spent fuel pool 10 building long before you reach water levels that challenge j 11 the actual heat removal from the fuel. 12 MR. IBARRA: Okay. For a single bundle now 13 with 8 and a half feet of water above it, that's 20 l f\
\ 14 millirem. And, of course, that's more. You can do more :
I 15 with that now. And the area wouldn't be unaccessible. j 16 Very important for us were the heat load 17 calculations. And what comes into play here is how long 18 does it take for the water to boil if you were to lose 19 cooling. And we calculated that for a pressurized water 20 reactor, it would take about 12 hours; for a boiling water 21 reactor, about 7.4 hours. 22 Now, that's to initiate boiling. You still 23 have water in there. To reach the top of the fuel foria 24 pressurized water reactor, you have about 80 more hours;
) 25 and for a BWR, about 50 more hours. So you have plenty of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
223 1 time to correct problems. I 1 I 2 You can see here how come we picked eight c. '\' 3 hours in some of our calculations, some of the degrees 4 here, to calculate frequencies. 5 (Slide) 6 MR. IBARRA: Now, what has been happening in 7 the industry is that the refueling outages are getting i 8 shorter. And, of course, that's a concern for us because 1 9 you're putting more heat load or more heat into the spent l 10 fuel pool. 11 We were able to get some information from Nine 1 12 Mile Point Unit 2 to see what's happening in the industry. 13 And it does typify what's been happening. In Outage ( 14 Number 1, it took them 35 hours to do the offload. But in 15 the last outage, it was like 13 hours. l 1 16 MR. ORNSTEIN: Days. 17 MR. IBARRA: I'm sorry. Days. Yes. Days. 18 I'm sorry. 19 So you can see that it would be a heavier load 20 here. 21 MEMBER KRESS: Is there a significant 22 difference in the decay heat -- 23 MR. IBARRA: Yes. 24 MEMBER KRESS: - between 13 and 35 days? (m. # 25 MR. IBARRA: Yes. And, in fact, right here it NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
224 i l l l 1 shows it. j i i i i f'N 2 (Slide) N-] Now, that outage that I was 3 MR. IBARRA: 4 talking about, it would take 51 hours -- and these are 5 calculations -- to initiate boiling. But in the last one, l I 6 they offloaded sooner. And they were down to 24 hours. j l 7 They have a configuration such that you can 8 put the gates in and out. Of course, if you put them in, I l 9 you have less water there. But you can see the trend. j i 10 You have less time now to correct problems. ; 11 MEMBER KRESS: That means the decay heat level 12 is about twice at the --
,- 13 MR. IBARRA: Well, yes. I would have to look
('-) 14 at that. Yes. 15 MEMBER KRESS: And those are all short-lived? 16 (Slide) 17 MR. IBARRA: The task about calculating risk, 18 about three years ago Pacific Northwest Laboratory did an 19 analysis on Susquehanna for NRR. And they wanted to 20 calculate near-boiling frequencies. 21 We looked at that analysis. And we corrected 22 for some of the deficiencies. And then we inputted our 23 own engineering assessments and our own operational data i l 24 to try to refine some of these numbers. ( (~)g x_ 25 Now, once again, their boiling is the point l NEAL R. GROSS ! C' a r l'.EPORTERS AND TRANSCRIBERS l '323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
225 1 that the water would begin to boil. You still have water 1 l (^] G 2 in there, but it's just the point of initiation of l 3 boiling. And what they had calculated for the total 4 near-boiling frequencies we estimate is about two and a 5 half times what they had calculated. 6 Now, this number is the total of a lot of 7 frequencies. And the two dominant ones are the loss of 8 off-site power and the inventory losses. As you can see, 9 for loss of off-site power, we say it's about three times 10 what they have calculated. 11 MEMBER FONTANA: Still, that could look like 12 awfully small numbers considering the experience that you
,-s 13 have had.
14 MEMBER KRESS: Did this study input your 15 initiating frequencies that -- 16 MR. ORNSTEIN: Yes. 17 MR. IBARRA: Yes. l l 18 MR. ORNSTEIN: Yes. In fact, when you take a 19 look at the bottom line on inventory losses, there's a 20 dramatic difference which is attributed to the data that 21 we were able to obtain. l l 22 MR. IBARRA: Like our data showed, there are a 23 lot of losses that had not been accounted for. And, like 24 Hal said, that's 20 times what was previously believed.
,a s- 25 MEMBER KRESS: Now, at this point, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
(202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
226 1 near-boiling, we haven't lost any water. 2 MR. IBARRA: Right. We have not lost any (m) v 3 water. And that's how come -- my next point is that this 4 number, we still believe that it's an order away from 5 causing damage to the fuel because it's small. 6 MEMBER CATTON: Well, you've still got some 40 1 7 hours or so, don't you? 8 MR. IBARRA: You have a lot of time, yes. ) 9 MEMBER CATTON: Before you boil it down to the 10 fuel, you've got a lot of time to fix your problem. I 11 MR. ORNSTEIN: Now, that's in the case of just 12 a loss of cooling, as opposed to the inventory event, i 13 where it's a different story. ) ( U 14 MEMBER KRESS: That is a different story. 15 You're right. 16 MR. IBARRA: Okay. So, even though -- and, in 17 fact, this number is low, which is good. But we feel that 18 there are a lot of improvements that can be made in this 19 category to reduce that number even more. 20 MEMBER KRESS: Can we assume the containment 21 is open during these events? Generally it's a shutdown 22 case or not? 23 MR. IBARRA: It was -- 24 MR. BILL JONES: You really can't assume that. (N
'N 25 When you move fuel, generally you would have to bave the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
(202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433
I 227 l 1 containment shut. When the fuel is not being moved,
-w 2 what's true is they can be doing a lot of things. And ;
f s
\ ) . %/
3 containment could be open. 4 MEMBER KRESS: Could be open? l 5 MR. BILL JONES: Could be. i 6 (Slide) i 7 MR. IBARRA: Now, the Susquehanna analysis 8 done by PNL points out very important items that we agree 9 with. And that is that if you make some small l l 10 improvements, you can reduce the risk of coming to the i 11 boiling point and -- 12 MEMBER KRESS: When you say " risk," what do 13 you mean? Reduce those numbers near-boiling frequency or j
\ 14 inventory loss or --
15 MR. IBARRA: These numbers would be smaller, 16 which would make that smaller. 17 MEMBER KRESS: Did they actually calculate a l 18 core damage frequency? 19 MR. IBARRA: No. They didn't, and we didn't. 20 But this gives you a gauge. 21 MEMBER KRESS: Yes. You can assume it's lower 22 than that. 23 MR. IBARRA: Right. 24 MR. ORNSTEIN: Basically it was an estimate. A k ,) 25 It was a rule of thumb. It was a very imprecise NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C 20005-3701 (202) 234-4433
228 l l 1 evaluation. And it was believed that it would be a factor p 2 of 1,000 between getting to the point of near-boiling N.] 3 until you actually do damage fuel. 4 But the concern is that that type of l 5 assessment is truly unreliable because you then get to a 6 point of many plant-specific things that could be done. 7 And it's really a big question. 8 Basically, the perception is the likelihood of 9 the event driving towards damage is quite low relative to 10 normal at-reactor-power events. 11 MEMBER KRESS: Given that as a conclusion, are 12 you still deciding that there ought to be some 13 improvements made? I :
\ 14 MR. IBARRA: Yes. Let me continue. One more 15 thing about Susquehanna. Susquehanna has two reactors 16 with a shared spent fuel pool. Actually, the spent fuel 17 pools could be connected. And when you're connected and 18 you're refueling and one of the pools that's refueling 19 boils, you can effect the operating unit. That's very 20 important, very important to consider.
21 (Slide) 22 MR. IBARRA: Now, getting into our findings 23 and conclusions, after looking at 12 years of operational t l 24 experience, we see that the actual consequences have not l i p) (_, 25 been severe. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 2344433 WASHINGTON. D C. 20005-3701 (202) 234 4433
t l 229 1 MEMBER KRESS: It's because you haven't seen l 2 any consequences; right? (]
'%.)
3 MR. IBARRA: Because we have not seen 4 consequences. And you know the events have occurred and 5 what has happened. 6 MEMBER KRESS: Okay. 7 MR. IBARRA: That has been mostly due to 8 configuration control. That's the human element. And, 9 like we just mentioned, the relative risk of fuel damage 10 is low compared with the reactor. 11 MEMBER CATTON: It's even less than that, 12 isn't it? The consequences of actual events have not been 13 severe? There have been no consequences, have there? i )
\# 14 MR. IBARRA: Well, yes. You might --
15 MEMBER CATTON: It looks like you never boiled 16 the pool. ; I 17 MR. IBARRA: We were looking -- our assessment l 1 18 is what happens when you lose cooling. And we've lost 19 cooling. 20 MEMBER CATTON: Okay. So what is this 21 consequence? l l 22 MR. ROSSI: Well, I think what he's talking 23 about is there have been consequences of heating up the l l 24 pool some number of degrees or dropping the level down. i ! e , (_ 25 And those are consequences from events that you would NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON D.C. 20005-3701 (202) 234-4433
230 1 prefer not to occur, but they're clearly not severe. T 2 I'm Ernie Rossi. I'm from AEOD also. fY 3 MEMBER CATTON: I think I would have used the l 4 word " trivial," but -- I 5 MR. ORNSTEIN: Well, on the other hand, there 6 have been cases where there were radiological releases l 7 from the pool into the pool area. And if you are a 8 worker, it might have been considered consequential by 9 you. 10 MR. IBARRA: We calculated -- and these are 11 calculations from operating experience -- that the loss of 12 coolant over one foot is about one occurrence per 100
-s 13 reactor years. And the loss of coolant that results in
> e 14 greater than 20 degrees is about 2 to 3 occurrences in 15 1,000 reactor years. 16 MEMBER FONTANA: That's from experience? 17 MR. IBARRA: From experience. 18 MEMBER KRESS: Yes. 19 MEMBER FONTANA: Well, that's what gives me a 20 problem with your 5 times 10 4 on the other one because if 21 you add these 2 together, you get something like 30 out of 22 12 or 13 per 1,000 reactor years. 23 MR. ROSSI: But I think the other one was all 24 the way up to near boiling. b) (. 25 MEMBER FONTANA: Yes, I understand. I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON D C. 20005-3701 (202) 2344433
231 1 understand. But the difference between this number and r~ 2 one out of 50,000 is some intervening action that keeps it 3 from going the rest of the way. Is that realistic? 4 MR. ORNSTEIN: Well, there's something that I 5 think you may not be focusing on. What you see on this 6 chart on the findings and conclusions, that's as a result 7 of review, 700 different events. 8 Now, the previous chart that you saw was that 9 which was done for Susquehanna plants specifically. It 10 was not the general overall operational experience 11 database. And this is sort of getting to the point that 12 we have a better feel for the specifics at Susquehanna, ,_ 13 and we have a feel for the overall industry on experience. 14 But there's a great deal of uncertainty as to all of the i 15 other plants being in the same boat. 16 It's hard to go ahead and do a generic study 17 and have a direct plant-specific application. I think 18 you're starting to see this type of thing occurring. 19 MEMBER KRESS: So that third bullet really 20 only refers to Susquehanna? 21 MR. ORNSTEIN: The analysis that was done with 22 the figures on the previous slide, yes. 23 MR. IBARRA: Yes. 24 MEMBER KRESS: And in that Susquehanna study, /~~' (_)s 25 you did feed these numbers in as an input? NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
232 1 MR. IBARRA: Correct, correct. And that's how g- 2 come you see the differences in how many inventory losses LJ and loss of off-site power. l 3 4 So, as has been mentioned, the likelihood is 1 5 small. And the consequences are not that great or not l l 6 that grave, I should say. But we still feel that there is 1 7 a lot of room for improvement. And you would reduce the i 8 risk even further. 9 MEMBER KRESS: Are these improvements l 10 voluntary? Are they backfits or suggestions or -- 11 MR. IBARRA: Well, we still are talking about 12 that to NRR that would implement them. And my final slide l ! 13 talks a little bit about that. ! i I i
/ 14 MEMBER KRESS: Okay. I i
15 (Slide) 16 MR. IBARRA: But surely, as we saw, 17 configuration control is the number one contributor to 18 some of these events. And if you improve that, you can 19 mitigate or even stop the events from happening. Like the 20 Susquehanna scenario, when you have multi-unit sites, 21 there is the potential of one boiling affecting the other l 22 unit. 23 And then for response, like I mentioned, the 24 outages are getting shorter. And they're going to have to p) (, 25 start paying attention to the boiling times. i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234 4433
233 I i 1 Training procedures can need improvement. Of j r~s 2 course, the better trained the operators are, the better (
\%/
)
3 off you're going to be in being able to reduce the risk. 4 And, like I talked about in our assessment of 5 instrumentation and power, we feel that those can be 6 improved. The more information that you're able to give 7 the operator, the better off he's going to be able to cut 8 the event short. 9 Power supplies. They need to look at 10 alternate means of supplying power in case they lose the 11 main power source. 12 (Slide) I 13 MR. IBARRA: Now, for follow-up, what has l l ,_,'s . ! s
\/ 14 happened to our report? Our report was finished in 15 September of last year. We did brief the Commission on l
16 November 14th. We are presently working on an information 17 notice. And we are going to turn our assessment into a 18 NUREG. This I would expect in the next month or so. ! 19 We're also letting the international community l l We did use some of their data, l j 20 know about our assessment. 1 ! 21 not in our own analysis, but to see how they relate to us. 22 And they're consistent with our findings. 23 Then we are working with NRR on trying to find 24 out what's going to happen to some of the recommendations
~
(N 'j) 25 that we're proposing. I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE , N W l (202) 234-4433 WASHINGTON. D C 20005-3701 (202) 234-4433 l
234 1 MEMBER KRESS: Will they need to be subjected ,e~s 2 to regulatory analysis, do you think? !v) 3 MR. IBARRA: Yes. 4 MR. ROSSI: Well, let me say a couple of 5 things. First of all, we're going to send an information 6 notice out to make all of the utilities aware of the 7 findings of our study, including the possible things that 8 can be done to reduce the probability of having any severe 9 events. 10 And these are relatively easy things to 11 implement. They are things like training, better l 12 configuration control, using diagrams in the control room,
- 13 that kind of thing. So the information notice will not ~'
14 require any actions. But we would prefer or we would 15 assume that a prudent utility would do the things that are 16 fairly straightforward and inexpensive to do to reduce the 17 likelihood of these kinds of events. 18 And, as Jose indicated, we'll be working with 19 NRR on whether there are things that need to go to the 20 CRGR and be required of people. 21 MR. IBARRA: When we had the opportunity to go 22 to Millstone, they were very interested in seeing what we 23 had to say about their units. And I think the visit to 24 Millstone, at least in my mind, validated what our (O _) 25 findings were because, like I mentioned before, they had a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISt.AND AVE., N W. (202) 234 4433 WASHINGTON. D C. 20005 3701 (202) 234 4433
235 1 draindown. And, all of a sudden, you find visual aids in l l (~3 2 the control room. ( %J 3 We had seen that. In fact, we're saying 4 that's a good thing to have visual aids for the operator. 5 MEMBER KRESS: It seems to me like your study 6 has shown that there's a good probability that this is a 7 low-risk event but that there may be some specific 8 plant-specific problems out there that could be relatively 9 easily fixed and that based on the study you put out an 10 information notice that passes that information along to 11 the right people. 12 And now you're looking at the possibility of _ 13 maybe requiring some of those things by going through NRR. 14 And that may or may not be a backfit or may or may not 15 require reg analysis. 16 Is that right? 17 MR. ROSENTHAL: Our work with NRR would be 18 subject to reg analysis and formal backfit. And we would 19 go through CRGR. And it's very hard to make a 20 cost-beneficial argument or even a large incremental risk 21 argument because we believe that the risks are low. 22 One of the purposes of the whole study was to 23 do an independent study. There was a lot of interest in 24 this area and to -- s0 (_,1 25 MEMBER KRESS: Independent like what? NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
i 236 1 MR. ROSENTHAL: Independent of NRR, 2 independent of the licensees. We just set some people g-] C/ 3 aside to look at the data and to try to factually present 4 what we have. 5 And we believe that the risks are low, but we 6 think that there could be some vulnerabilities out there. 7 It would be prudent to have the individual licensees look 8 at them. And in certain selected cases, depending on what 9 instrumentation they have, it may pay for them to upgrade 10 subject to the backfit. I think it's a very measured 11 response that we're trying to get. 12 MR. IBARRA: Some utilities for the operator l 13 now, the operator in the control room, he has no /' s\ 14 indication of what's happening out there because it's not 15 continuous information coming to him. He knows when , i 16 there's a problem when the alarm goes off. 17 We're coming from the point as: How come he l 18 doesn't know what's happening all the time? How come you , 1 19 can't have an analog instrument so you can see the trend 20 and fix the problem before it becomes more critical? 21 Okay. That's all we're saying. The more 22 information you have, the better off you're going to be. 23 MR. ROSENTHAL: Dr. Kress, for example, there 24 is one plant in which they didn't have the holes drilled ,a (_j) 25 in the vacuum breakers. There's another plant in which NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
237 1 they had drilled the holes in the vacuum breakers and, 2 because they're going through some other evolution, some 7-) N.) 3 years before had plugged those holes so that the vacuum 4 breakers weren't operable. 5 I mean, that's a casic precept of this pool. 6 And that is that you suck the water in and out from the 7 top. So you make sure it's there. And the vacuum 8 breakers ought to be operable. Maybe somebody needs to go 9 over to the side of the pool and put their finger down 10 there and see that there's a hole there. 11 MEMBER KRESS: See if that hole is -- 12 MR. ROSENTHAL: Now, we may not be able to 13 make a cost-benefit argument that people should do this, l')
/ 14 but there's a certain amount of prudence and pragmatism 15 that goes with at least informing people.
16 And I think we're dealing with honest brokers. 17 When we put the information out, I think most people, most 18 licensees, are concerned people and I think, given that 19 NUREG, will take it to heart. 20 MEMBER KRESS: Are there any plans for a 21 follow-on look later on to -- 22 MR. ROSENTHAL: With NRR in the course of -- 23 you know there's a proposal to add shutdown pool cooling 24 to the propos:S rule on shutdown. And there would be a l} ( ,/ 25 proposal there to openly develop SRP and reg guide. But I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISt.AND AVE., N W. l (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 224-4433 l
238 1 it's in the very formative stages. And then there would r~s 2 be some associated inspection of those plants that are (v) 3 considered most vulnerable because of their geometry. 4 But we would do all of that through NRR, but 5 I'm sure we'll be supportive of them. 6 MR. IBARRA: We have had an impact, though, on 7 the current site-specific inspections that NRR is doing. i 8 And then I think they've added cavity seals, which were 9 not considered before. And that's a precursor to a big 10 problem if they were to lose water. 11 So we have had some influence. And, like I I i 12 said, we've had a lot of calls from the utility people i 13 actually wanting information on what we found. I think it t.p_) 14 would be useful to the industry. 15 MEMBER FONTANA: Just out of curiosity, how 16 old does the fuel have to be to be cooled by a national 17 circulation of water? And how old does it have to be 18 before it can be just air cooled? Just curious. 19 MR. IBARRA: I don't know that. Hal? 20 MEMBER KRESS: To keep the plant below 1,200 21 deg' cees would be -- 22 MR. ORNSTEIN: I don't want to give you a 23 guess. 24 MEMBER FONTANA: I was just curious. 1 ( ,/ 25 MR. IBARRA: That's all I have. l NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433 I l l
239 ! 1 MEMBER KRESS: Well, thank you. It's been t rm : 2 very useful and very, very good.
\J' 3 Do any of the other member- it to --
4 VICE CHAIRMAN POWERS: I wondered if in the 5 course of doing your surveys that you had given a 6 prospective look at the consequences of trying to store 7 high burn-up fuel in the pools. 8 MR. IBARRA: No. 9 MEMBER KRESS: The decay heat of high burn-up ] 10 fuel ought to almost be linear after it loses the i 11 short-lived. 12 VICE CHAIRMAN POWERS: I'm not so concerned 13 about decay heat because I think we have the procedures l'-s) 14 for handling that. And people understand that very well. 15 MEMBER KRESS: You can calculate that. And 16 you'll know what that is. Yes. 17 VICE CHAIRMAN POWERS: And the tools are set 18 up for doing that, but I -- i 19 MEMBER KRESS: Except these numbers that they 20 use for a gauge of risk are dependent on the decay heat. 21 MR. IBARRA: That's correct. 22 VICE CHAIRMAN POWERS: What I am more l 23 concerned about is that we have clad that's hydriding. 1 1 24 Hydrides usually are fairly incompatible with water. l I tO () 25 MEMBER KRESS: Usually. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. l (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433 l J
240 1 VICE CHAIRMAN POWERS: We have clad that is (~] Q,) 2 extremely embrittled. Handling accidents, fragmenting the 3 fuel, leeching fuel sudden 2y become much more probable 4 types of events. 5 MEMBER KRESS: You're likely to increase the 6 handling problems and the normal levels of radiation in
- 7 the pool and that sort of problem, as opposed, I think, to 8 increasing the loss of spent fuel pool risk would be my 9 guess, even though I think you may have a higher decay 10 heat, which would --
11 VICE CHAIRMAN POWERS: You may have a higher 12 hydrogen problem. 13 MEMBER KRESS: More hydrogen. Hydrogen may be 4 O 14 a problem. Okay. , l 15 Any other questions? 16 (No response.) 17 MEMBER KRESS: Well, we thank you, then. And 18 I'll turn the program back over to the Vice Chairman, Dr. l 19 Powers. Where are we on this? 20 VICE CHAIRMAN POWERS: We are substantially 21 ahead of schedule. 22 MEMBER KRESS: Oh, wonderful. 23 VICE CHAIRMAN POWERS: I will not congratulate 24 Dr. Kress. I will criticize him for poor planning.
.O
(/ 25 (Laughter.) NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
241 l 1 MEMBER FONTANA: Can't win either way, can l (N ) 2 you? Q,) 3 VICE CHAIRMAN POWERS: That's right. 4 MEMBER KRESS: Well, we'll break for lunch 5 early. We can go back and do some work. 1 6 VICE CHAIRMAN POWERS: We are early enough I 7 think we would be remiss not to take advantage of this 8 time. 9 MEMBER KRESS: I've got some things I can do 10 with it, yes, like write letters. 11 (Whereupon, the foregoing matter was concluded 12 at 11:41 a.m.) 13
,g f
'%. 14 15 16 17 18 19 20 21 22 l 23 24 i rO Q ,) 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
(202) 234 4 433 WASHINGTON, D C. 20005-3701 (202) 234-4433
n v CERTIFICATE This is to certify that the attached proceedings before the United States Nuclear Regulatory Commission in the matter of: i Name of Proceeding: 438" ACRS ' Docket Number: N/A Place of Proceeding: ROCKVILLE, MARYLAND were held as herein appears, and that this is the original i transcript thereof for the file of the United States Nuclear l Regulatory Commission taken by me and, thereafter reduced to typewriting by me or under the direction of the court reporting company, and that the transcript is a true and accurate record of the foregoing proceedings. mhtPa (_CO"RIfETT RINIR Official Reporter Neal R. Gross and Co., Inc. 1 O i NEAL R. GROSS COURT REPORTERS AND TRANSCRIDERS I323 RilODEISLAND AVENUE,NW (202)234-4433 WASIIINGTON, D C. 20005 (202)2344 433 9
l 1 INTRODUCTORY STATEMENT BY THE ACRS CHAIRMAN 438TH ACRS MEETING, FEBRUARY 6-8, 1997 THE MEETING WILL NOW COME TO ORDER. THIS IS THE SECOND DAY a i OF THE 438TH MEETING OF THE ADVISORY COMMITTEE ON REACTOR SAFEGUARDS. DURING TODAY'S MEETING, THE COMMITTEE WILL CONSIDER THE FOLLOWING: ) (1) RISK-INFORMED, PERFORMANCE-BASED REGULATION AND RELATED MATTERS (2) RESULTS OF THE STUDY PERFORMED BY AEOD ON THE CONSEQUENCES OF AN EXTENDED LOSS OF SPENT FUEL POOL COOLING (3) PROPOSED ACRS REPORTS THIS MEETING IS BEING CONDUCTED IN ACCORDANCE WITH THE PROVISIONS OF THE FEDERAL ADVISORY COMMITTEE ACT.
,Q , MR. SAM DURAISWAMY IS THE DESIGNATED F'EDF.RAL OFFICIAL FOR THE INITIAL PORTION OF THE MEETING.
WE HAVE RECEIVED NO WRITTEN STATEMENTS OR REQUESTS FOR TIME l TO MAKE ORAL STATEMENTS FROM MEMBERS OF THE PUBLIC REGARDING TODAY'S SESSIONS. A TRANSCRIPT OF PORTIONS OF THE MEETING IS BEING KEPT, AND IT IS REQUESTED THAT THE SPEAKERS USE ONE OF THE MICROPHONES, IDENTIFY THEMSELVES AND SPEAK WITH SUFFICIENT CLARITY AND VOLUME SO THAT THEY CAN BE READILY HEARD.
- o!
Of ,\ United States O O ~~ i i,
) Nuclear Regulatory Commission REGELATORY GLIDES AND .
STANDARD REVIEW PLANS IN SUPPORT OF RISK INFORMED REGELATION PRESENTATION TO ACRS FELL COMMITTEE FEBRL ARY 7,1997 Gary Holahan, NRR (415-2884) Thomas King, RES (415-5790) Robert Jones, NRR (415-2198) Mark Cunningham, RES (415-6189)
O O O 1 INTRODUCTION DRAFT REGULATORY GUIDES (RGS) AND STANDARD REVIEW PLANS (SRPS) HAVE BEEN PREPARED TO HELP IMPLEMENT THE COMMISSION'S AUGUST 1995 POLICY ON THE USE OF RISK INFORMATION IN THE REGULATORY PROCESS.
- FOR REACTOR LICENSEES
- FOR PLANT SPECIFIC CHANGES TO A PLANT'S CURRENT LICENSING BASIS (CLB).
OBJECTIVES OF RGS/SRPS: l 8 DESCRIBE OVERALL APPROACH / EXPECTATIONS / PROCESS e PROVIDE PRINCIPLES AND GUIDANCE FOR DETERMINISTIC AND PROBABILISTIC ANALYSIS AND INTEGRATED DECISION MAKING
- DESCRIBE PERFORMANCE BASED IMPLEMENTATION STRATEGV
- PROVIDE GUIDANCE ON INFORMATION THAT SHOULD BE.
SUBMITTED FOR REVIEW. l USE OF RG/SRPS IS VOLUNTARY FOR LICENSEES I
- i l
1 i
O O O . e _ INTRODUCTION (CONT) SCOPE OF RGS/SRPS: l e GENERAL GUIDANCE (DG-1061 + SRP) j e APPLICATION SPECIFIC GUIDANCE l - IN-SERVICE TESTING (DG-1062 + SRP) TECHNICAL SPECIFICATIONS (DG-1065 + SRP) GRADED QA (RG ONLY) DG-1064) IN-SERVICE INSPECTION (ON A LATER SCHEDULE) e SUPPORTING DOCUMENT: NUREG-1602 - INFORMATION ON SCOPE AND QUALITY OF PRA ANALYSES i ; 2 l
O O O '! INTRODUCTION (CONT) STATUS OF RGS/SRPS:
- FINAL DRAFTS FOR ACRS REVIEW:
GENER.AL RG/SRP (MINuS APPENDICES) - DRAFTS PROVI6ED MIc-JANUARY APPLICATION SPECIFIC RGS/SRPS AND GENERAL RG/SRP APPENDICES - DRAFTS PROVIDED FEBRUARY 7, 1997 PURPOSE OF TODAY'S STAFF PRESENTATION:
- UPDATE ACRS ON CHANGES MADE TO GENERAL RG/SRP AS A RESULT OF NRC STAFF / MANAGEMENT REVIEW SUBSEQUENT TO LAST MEETING
- RESPOND TO SPECIFIC QUESTIONS RAISED AT THE JANUARY 28, 1997, ACRS SUBCOMMITTEE MEETING
- SOLICIT FEEDBACK FROM ACRS MEMBERS ON OVERALL APPROACH / GUIDELINES 8- NO LETTER REQUESTED AT THIS TIME
O O O' .- i SCHEDULE FEB 20-21, 1997 - ACRS SusCOMM ON PRA - REVIEW OF i GENERAL RG APPENDICES AND APPLICATION SPECIFIC RGS/SRPS MARCH 6 OR 7, 1997 - ACRS FULL COMMITTEE - STAFF PRESENTATION ON APPLICATION i SPECIFIC RG/SRP . MARCH 14, 1997 - ACRS LETTER MARCH 24, 1997 - PACKAGE TO EDO i MARCH 31,1997 - PACKAGE TO COMMISSION 4 l
o o o Ll i JANUARY 22. 1997 SRM STAFF PRESENTED FOUR POLICY ISSUES, OPTIONS AND - RECOMMENDATIONS IN AN OCTOBER 11, 1996, SECY PAPER 1/22/97 SRM PROVIDES COMMISSION GUIDANCE ON POLICY ISSUES
- e PERFORMANCE BASED REGULATION e USE OF SAFETY GOALS FOR PLANT SPECIFIC APPLICATION e RISK NEUTRAL VS. RISK INCREASE e APPROVE ACCEPTABLE ALTERNATIVES FOR ISI UNDER 10 CFR 50.55A 5
j
O MAJORCHANGESpNGENERALRG/SRP O' t EMPHASIS ADDED ON OVERALL EXPECTATION OF IMPROVED SAFETY BY COMPREHERSIVE CONSIDERATION OF RISK INFORMATION
- RISK REDUCTION e BURDEN REDUCTION e CUMULATIVE IMPACT OF CHANGES IN RISK i
SAFETY GOAL SUBSIDIARY OBJECTIVES DEFINE INSIGNIFICANT RISK. CHANGES IN RISK BELOW THOSE VALUES ARE CONSIDERED "SMALL" REMOVED FIGURES OF CDF vS. *CDF AND LERF vS. *LERF REGIONS DEFINED WHERE: e REASES ARE NOT ACCEPTABLE CALCULATED (CDF>10 '; RISK LERF>10- INp/RY) e EASES ARE LI ELY TO BE CALCULATED ACCEPTABLE (CDF<10- RISK INg/RY; LERF<10-{)
- CALCULATED RISK INCREASES WILL RECEIVE IN EASED GEMENT ATTE TION W EN IN THE RANGE 10 /RY-MAy/RY 10 CDF; 10 p/RY-10 g/RY LERF EXPANDED DISCUSSION OF UNCERTAINTIES UPDATING APPENDICES 6
---_...--.7.-
O O O OVERALL APPROACH. DEFINE PROPOSED CHANGE 1 DEMONSTRATE THAT CERTAIN FUNDAMENTAL SAFETY PRINCIPLES ARE MET:
- e MEET REGULATIONS (OR PROPOSE A CHANGE / EXEMPTION) e MAINTAIN DEFENSE-IN-DEPTH
- e MAINTAIN SUFFICIENT SAFETY MARGIN e NO SIGNIFICANT INCREASES IN RISK TO PUBLIC HEALTH l
AND SAFETY e IMPLEMENT UTILIZING PERFORMANCE BASED MONITORING AND FEEDBACK STRATEGIES ) EXPECTATIONS ON IMPLEMENTATION: e ASSESS ALL SAFETY IMPACTS e SCOPE OF ANALYSIS SUPPORTING THE CHANGE SHOULD COVER I ALL SSCS, OPERATING MODES, INITIATORS AFFECTED BY THE CHANGE AND REFLECT THE AS BUILT, AS OPERATED PLANT 7
],
O O OVERALL APPROACH (CONT) O '
- SUBSIDIARY OBJECTIVES OF COMMISSION'S SAFETY GOAL i
POLICY USED TO DEFINE BENCHMARK RISK LEVELS FOR DECISION MAKING: 10-*/RY - CORE DAMAGE FREQUENCY (CDF) 10-5/RY - LARGE EARLY RELEASE FREQUENCY (LERF) e PROPOSED CLB CHANGES SHOULD BE MADE IN SMALL i INCREMENTS (<10% OF BENCHMARK CDF/LERF VALUES) AND ! WHEN WITHIN A FACTOR OF 10 OF THE BENCHMARK VALUES, THE MORE ANALYSIS AND MANAGEMENT REVIEW WILL BE NECESSARY.
- PERFORM UNCERTAINTY / SENSITIVITY ANALYSIS APPROPRIATE i FOR PROPOSED CHANGE e PERFORM QUALITY ANALYSES AND MAKE IT AVAILABLE FOR
! PUBLIC REVIEW l PERFORMANCE MUST BE MONITORED TO HELP VERIFY KEY ASSUMPTIONS AND CHECK AREAS OF LARGE UNCERTAINTY DOCUMENTATION 8
O O O .. i TOPICS RAISED sY ACRS SusCOMMITTEE ON PRA FOR DISCUSSION WITH FULL COMMITTEE GUIDELINES ON USE OF DEFENSE-IN-DEPTH HOW TO MAINTAIN SUFFICIENT SAFETY MARGIN PLANT SPECIFIC LERF TREATMENT OF TEMPORARY CHANGES IN RISK IMPACT OF PILOT PROGRAMS PEER REVIEW / EXPERT PANEL i l l i 9
*l O O O -
DEFENSE-IN-DEPTH , GUIDELINES FOR MAINTAINING DEFENSE-IN-DEPTH: ,
- A REASONABLE BALANCE AMONG PREVENTION OF CORE DAMAGE, PREVENTION OF CONTAINMENT FAILURE, AND CONSEQUENCE MITIGATION IS PRESERVED e OVER-RELIANCE ON PROGRAMMATIC ACTIVITIES TO i COMPENSATE FOR WEAKNESSES IN PLANT DESIGN IS AVOIDED
- SYSTEM REDUNDANCY, INDEPENDENCE, AND DIVERSITY ARE MAINTAINED COMMENSURATE WITH THE EXPECTED FREQUENCY ,
AND CONSEQUENCES OF CHALLENGES TO THE SYSTEM (E.G., NO RISK OUTLIERS)
- DEFENSES AGAINST POTENTIAL COMMON CAUSE FAILURES ARE MAINTAINED AND THE INTRODUCTION OF NEW COMMON CAUSE FAILURE MECHANISMS IS AVOIDED !
i
- INDEPENDENCE OF BARRIERS IS NOT DEGRADED I
- DEFENSES AGAINST HUMAN ERRORS ARE MAINTAINED l 10 l
O O O 'l DEFENSE-IN-DEPTH (CONT) GUIDELINES FOR APPLICATION OF DEFENSE-IN-DEPTH:
- RELY ON TRADITIONAL ENGINEERING JUDGMENT FOR AREAS OF LARGE UNCERTAINTY OR AREAS NOT COVERED BY RISK ANALYSIS i
- USE RISK INSIGHTS, WHERE SUPPORTED BY APPROPRIATE I RISK ANALYSES, TO HELP GUIDE APPLICATION OF DID AND PROVIDE BASES FOR DEMONSTRATING DID IS MAINTAINED i i
11
~
O O O .. SAFETY MARGINS i
- i I
GUIDELINES FOR MAINTAINING SUFFICIENT SAFETY MARGINS:
- CODES AND STANDARDS OR ALTERNATIVES APPROVED FOR USE BY THE NRC ARE MET
- SAFETY ANALYSIS ACCEPTANCE CRITERIA IN THE CURRENT I LICENSING BASIS (E.G., FSAR, SUPPORTING ANALYSES)
ARE MET, OR PROPOSED REVISIONS PROVIDE SUFFICIENT MARGIN TO ACCOUNT FOR ANALYSIS AND DATA UNCERTAINTY MARGINS CAN BE MEASURED BY: i i e DETERMINISTIC CRITERIA
- RISK ASSESSMENT !
12 i t il
O O O .l ; PLANT SPECIFIC LERF ; e A VALUE OF 10-5/RY IS RECOMMENDED AT THE BENCHMARK LERF GUIDELINE, ALONG WITH A REGION.OF INCRF e l ATTENTION WHEN LERF IS IN THE RANGE 10 pSED MANAGEMENT S/RY. BASED UPON PROVIDING REASONABLE ASSURANCE THAT , SAFETY GOAL QHO'S ARE MET, WITHOUT BEING A DEFACTO NEW GOAL ISTENT WITH PREVIOUS ANALYSIS OF SUGGESTED coy 10 /RY LARGE RELEA E GUIDELINE
- CONSISTENT WITH 10 j/RY CDF AND 0.1 CCFP SAFETY GOAL !
1
- SUBSIDIARY OBJECTIVES i
e SINGLE VALUE CHOSEN TO: i - ALLOW USE OF LEVEL 1 AND 2 PRA ONLY AVOID UNCERTAINTY ASSOCIATED WITH LEVEL 3 ANALYSIS BE CONSISTENT WITH PREVIOUS col #4ISSION DIRECTION TO DECOUPLE SITING FROM PLANT DESIGN PROVIDE UNIFORM AND CONSISTENT GUIDELINES TO ALL PLANTS 13
O O O ., TREATMENT OF TEMPORARY CHANGES IN RISK GENERAL RG/SRP PROVIDE GUIDELINES ON CHANGES IN
- CDF/LERF IN TERMS OF ANNUAL AVERAGE VALUE RG/SRP ON TECHNICAL SPECIFICATIONS PROVIDES ADDITIONAL GUIDELINES FOR ASSESSING ALLOWABLE OUTAGE TIMES (A0TS),
SINCE A0TS ARE BY THEIR NATURE TEMPORARY CONDITIONS. l - THESE GUIDELINES ARE STATED IN TERMS OF PROBABILITY (FREQUENCY TIMES A0T) FOR THE A0T PERIOD:
# CORE DAMAGE PROBABILITY <5x10-7
- LARGE EARLY RELEASE PROBABILITY <5x10-a I
THESE GUIDELINES ARE APPLIED IN ADDITION TO THE GUIDELINES ON ANNUAL AVERAGE CDF/LERF CONTAINED IN THE l GENERAL RG/SRP. i - AS AN EXAMPLE, THES GUIDELINES CORRESPOND TO A TEMPORARY CDF OF 10g/RY FOR A 5 HR A0T PERIOD. FEDERAL REGISTER NOTICE WILL SOLICIT INPUT ON WHETHER ; ADDITIONAL GUIDANCE ON TEMPORARY CHANGES IN CDF/LERF ! ARE DESIRABLE AND, IF SO, WHAT T::OSE SHOULD BE. 1 l l 14 a
l O IMPACTOF#LOTPROGRAMS O '! PILOTS UNDERWAY IN ALL FOUR APPLICATION SPECIFIC AREAS RGS/SRPS HAVE BEEN IMPACTED BY THE PILOTS BY: e TESTING THE GUIDANCE BEING DEVELOPED FOR APPLICABILITY AND PRACTICALITY e IDENTIFYING ISSUES THAT NEED ATTENTION i PILOTS HAVE BEEN IMPACTED BY RG/SRP DEVELOPMENT BY: , o PROMPTING QUESTIONS BASED UPON THE GUIDANCE BEING DEVELOPED i DUE TO THE EVOLVING NATURE OF THE RGS/SRPS, ADDITIONAL INTERACTION AND FEEDBACK REMAINS. t- [ f 15
.t o e PEER REVIEW EXPERT PANEL O '
PEER REVIEW - ONE ACCEPTABLE WAY FOR LICENSEES TO ENSURE QUALITY OF PRA i - MENTIONED IN RGS/SRPS AS AN EXAMPLE DISCUSSED IN DRAFT NUREG-1602 (APPENDIX):
- PURPOSE e MEMBERSHIP / QUALIFICATION
- REVIEW PROCESS e DOCUMENTATION EXPERT PANEL - ONE ACCEPTABLE WAY FOR LICENSEES TO ,
IMPLEMENT INTEGRATED DECISION PROCESS MENTIONED IN GENERAL RG AS AN EXAMPLE DISCUSSED IN DRAFT GENERAL SRP (APPENDIX). ! STAFF REVIEW SHOULD DETERMINE THAT: j
- PANEL'S EVALUATION REPRESENTS j APPROPRIATE CONSIDERATION OF PRA, TRADITIONAL ENGINEERING, SENSITIVITY STUDIES, OPERATIONAL EXPERIENCE, !
ENGINEERING JUDGMENT AND CURRENT REGULATORY REQUIREMENTS ;
- PANEL MEMBERSHIP HAD APPROPRIATE COMPETENCE IN PERTINENT DISCIPLINES, EXPERIENCE AND TRAINING !
16 !
w O O O 'i . s. Advisory Committee on Reactor Safeguards February 7,1997 Observations on ; Risk-informed Regulatory Activities Tony Pietrangelo Director, Licensing Nuclear Energy Institute
1 First Principles Risk-informed initiatives should improve the focus of attention and resources commensurate with safety L PSA provides one additional input to the decision-making process
- NOT the sole basis for decisions
- PsA insights should be complementary, not supplementary Benefits (in safety or efficiency) of using PSA must outweigh the burden Recognition of PSA limitations h' r.
e e e;
O i O O .
. C; ,
Practical Use of PSA Industry must recognize that PSA is our tool and accept responsibility for its proper use and application Significant industry efforts underway to establish peer review process to demonstrate PSA quality and certification for applications Regulatory applications must be simple, straightforward, and must use PSA insights in the proper context
Observations l Progress is being made on the technical issues However Assumption appears to be made by NRC staff that risk-informed regulation will require numerous submittals by licensees i
- PSA is a tool to augment and complement CLB change process
- As a comparison, design changes can already be made without NRC staff advance approval under 10 CFR 50.59 f.
. . e ,:
- t
o O O 'l E; Observations (Continued) i NRC activities appear to be focusing on process of PSA rather than on using the insights Process and level of detail in draft NRC Reg Guides and SRP (to the extent known) appear to be potentially burdensome Need to ensure practical process commensurate with simple and straightforward applications as a starting point Methods, data and understanding will evolve and improve over time if practical applications are demonstrated
Observations (Continued) Need to develop review process and guidance that encourages, rather than discourages, use of PSA Treat as evolutionary, not revolutionary Caution with respect to " acceptance criteria" based on absolute figures of merit e e e ,
>t
O O O ' Conclusions Industry has significant investment in PSA It is in interest of industry and NRC to maintain momentum
- Industry has implemented many voluntary improvements on basis of i PSA insights '
L i 1
- Expectation has been that PSA will also provide a basis for regulatory improvement where appropriate .
l t I
Conclusions (Continued) . [ Use of PSA is " market driven"
- Some utilities already disbanding PRA organizations t
We believe needs of NRC can be accommodated and at the same time a workable and practical process can be developed
\
^ Industry comments will focus on these areas PSA is a means to an end, not an end in itself WB '- e O h'O y
~
O O O ~ p** "'%<g
*+ *'
i %**+ ASSESSMENT OF SPENT FUEL COOLING Jose G. Ibarra Reactor Analysis Branch Safety Programs Division Office for Analysis and Evaluation of Operational Data February 7,1997 '1 1 1
SPENT FUEL COOLING ASSESSMENT
- AEOD study requested by Executive Director for
- Operations.
- Developed generic configurations to assess loss of spent fuel pool cooling and inventory.
- Assessed 12 years of operational experience.
i
- Performed site visits to gather information on physical configuration, practices, and procedures _
- Reviewed regulations, standard review plan and regulatory guides.
- Performed assessments of electrical systems, instrumentation, heat loads, and radiation.
- Evaluated risk of losing spent fuel cooling.
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o O O i SPENT FUEL POOL EVENTS
- i TYPE EVENT ACTUAL PRECURSOR 1
SFP Inventory 38 55 Connected Systems 20 12 Gates & Seals 10 8 i Structure or Liner 8 35 h SFP Cooling 56 22 Cooling Flow 50 20 Heat Sink 6 2 i 1 5 I
LOSS OF COOLANT INVENTORY EVENTS i TYPE EVENT ACTUAL PRECURSOR Connected Systems 20 12 Configuration Control 16 2 l Siphoning 3 1 PWR TransferTube 1 1 Piping 0 1 Piping Seismic Design 1 1 Gates & Seals 10 8 Cavity Seals 0 6 Gate Seals 10 2 Pool Structure or Liner 8 35 Liner Leaks 7 1 i Load Drops 1 32 Pool Seismic Design 0 2 e O O .
-- . -. .- 1
O O O ..: r LOSS OF INVENTORY LEVELS NUMBER OF OCCURRENCES 10 l, 8 i 8 l 6 - 4 -------- ! 2 2 2 0
. <3 3 TO 12 12 TO 60 > 60 LEVEL DECREASE (INCHES)
J 7
I LOSS OF INVENTORY EVENTS NUMBER OF OCCURRENCES 8 7 7 i j 6 l l 5 = 1 ! 4 = 3 j 0
<1 1 TO 4 4 TO 8 8 TO 24 > 24 l DURATION (HRS)
\ . i \ O O O .
O O O - LOSS OF COOLING EVENTS l TYPE EVENT ACTUAL PRECURSOR Cooling Flow 50 20 SFP Pumps 39 8 Configuration Control 1 0
- Loss of Pump Suction 4 0 i
Flow Blockage 1 0 Single SFP Pump Failure 5 12
~
i Heat Sink fi 2 9 I
LOSS OF COOLING EVENTS NUMBER OF OCCURRENCES 20 16 15 10 6 5 3 : 0 0 0TO 20 MN 20TO 40 1 40TO 60 i TEMPERATURE INCREASE (DEG F) j 9 9 0 .
O O O ' LOSS OF COOLING EVENTS NUMBER OF OCCURRENCES 25 22 20 I 15 4 1@32 HRS ' 0 10 1@30 HRS-1@24 HRS 5 5 i 0 3 4 O
~
<1 1 TO 4 4TO 8 8TO 24 > 24 2
; DURATION (HRS) 11
i PARTIAL LISTING OF GOOD PRACTICES OBSERVED DURING PLANTVISITS t
- Utilization of system diagram prior to all alignment changes.
I
- Including SFP risk during outage planning.
- Classroom and simulator training to prepare for
! outage.
- User friendly graphs of pool heatup.
- Effective program for feedback of internal and industry operating experience. ,
- Detailed review at some plants found significant inventory loss vulnerabilities.
9 4 -- _ _ 9 .
REGULATION REVIEW AND ENGINEERING ASSESSMENTS e Identified applicable guidance and regulations.
- Surveyed 14 plants to determine power supply.
e Surveyed 14 plants to determine instrumentation. e Assessed radiation levels with varying water levels. e Performed heat load calculations. 13
AmM&A-m.a. & _m. ma-_4____a_m.& C.m. . . em.m.Am__ e d..J. 4_ kA--S 5d.h -.a.-sma ha $ m - . . m(m .A h -am.sa.- .m m m,m__ t .m -ma. ..w. .a -<a a.smwm__.._.a - s_m--u_.m=, _- .,,mm__m -., HISTORY OF FULL CORE OFF-LOADING NINE MILE POINT 2 z 40 3 35 00 35
$3 30 =
"i 24 a~ g 25
=
1 2 3 4 REFUEL OUTAGE NUMBER 1
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l 9 9 9 .
O O O .. NINE MILE POINT UNIT 2 I 60 en
$ 51 E GATES OUT O GATES IN 3J 40- 38.8
, O i 29.4 b 30-j 4 24.2 i 20- 17.6 13.6
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Lu 10- 84 E 0- i i i 1 2 3 4 REFUEL OUTAGE NUMBER 15
i NEAR-BOILING FREQUENCIES , CURRENT PREVIOUS INEL WORK PNL WORK Total Near-Boiling 5 E-5 2 E-5 Frequencies LOOP 3 E-5 1 E-5 Inventory Losses 2 E-5 1 E-6 l O O O
. O O O , SUSQUEHANNA SPENT FUEL POOL RISK ASSESSMENT t
- Showed benefits from:
improved instrumentation improved procedures improved training
- Showed vulnerability of operating unit from defueled unit i
4 17
FINDINGS AND CONCLUSIONS
- Likelihood and Consequences
- Consequences of actual events have not been severe.
- Primary cause of events has been human error.
- Relative risk of fuel damage is low compared with other reactor events.
1
- Highly dependent on human performance and plant design.
- Frequency of coolant loss > 1 foot,1/100 reactor years.
- Frequency of cooling loss > 20 F,2-3/1000 reactor l years.
t e e e .l
o o o ;l FINDINGS AND CONCLUSIONS (CONT.) Prevention
- Configuration control improvements can prevent and/or mitigate SFP events.
- Evaluations may be needed at some multiunit sites i for potential SFP boiling effects on safe shutdown.
Response
i
- Attention to time to boil with shorter outages. .
- Improved procedures and training may be needed.
- Improvements to instrumentation and power supplies may be needed.
19
4 i f FOLLOW UP
- Commission briefed on assessment.
- NRC Information Notice and being prepared.
- Study made into a NUREG.
- Report being submitted to incident Reporting System.
- Working with NRR on implementing recommendations.
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