ML18325A049
| ML18325A049 | |
| Person / Time | |
|---|---|
| Issue date: | 10/30/2018 |
| From: | Derek Widmayer Advisory Committee on Reactor Safeguards |
| To: | |
| Widmayer D A | |
| References | |
| NRC-3948 | |
| Download: ML18325A049 (359) | |
Text
Official Transcript of ProceedingsNUCLEAR REGULATORY COMMISSIONTitle:Advisory Committee on Reactor SafeguardsFuture Plant Designs SubcommitteeDocket Number:(n/a)Location:Rockville, Maryland Date:Tuesday, October 30, 2018Work Order No.:NRC-3948 Pages 1-NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.Washington, D.C. 20005(202)234-4433 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005
-3701 www.nealrgross.com 1 1 2 3 DISCLAIMER 4 5 6 UNITED STATES NUCLEAR REGULATORY COMMISSION'S 7 ADVISORY COMMITTE E ON REACTOR SAFEGUARDS 8 9 10 The contents of this transcript of the 11 proceeding of the United States Nuclear Regulatory 12 Commission Advisory Committee on Reactor Safeguards, 13 as reported herein, is a record of the discussions 14 recorded at the meeting.
15 16 This t ranscript has not been reviewed, 17 corrected, and edited, and it may contain 18 inaccuracies.
19 20 21 22 23 1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3+ + + + +4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5 (ACRS)6+ + + + +7 FUTURE PLANT DESIGNS SUBCOMMITTEE 8+ + + + +9 TUESDAY 10 OCTOBER 30, 2018 11+ + + + +12 ROCKVILLE, MARYLAND 13+ + + + +14 The Subcommittee met at the Nuclear 15 Regulatory Commission, Three White Flint North, Room 16 1C3 & 1C5, 11601 Landsdown S treet, at 8:30 a.m., 17 Michael L. Corradini, Acting Chairman, presiding.
18 19 20 21 22 23 24 25 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 2 1 COMMITTEE MEMBERS:
2 MICHAEL L. CORRADINI, Acting Chairman 3 RONALD G. BALLINGER, Member 4 DENNIS C. BLEY, Chairman*
5 CHARLES H. BROWN, JR., Member 6 VESNA B. DIMITRIJEVIC, Member 7 WALTER KIRCHNER, Member 8 JOSE MARCH-LEUBA, Member 9 JOY L. REMPE, Member 10 GORDON R. SKILLMAN, Member 11 12 DESIGNATED FEDERAL OFFICIAL:
13 GIRIJA SHUKLA 14 15 16*Present via telephone 17 18 19 20 21 22 23 24 25 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 3 1 A-G-E-N-D-A 2 Opening Remarks . . . . . . . . . . . . . . . . . 4 Staff Introduction ..
..............6 3 4 Licensing Modernization: Technology-Inclusive, 5 Risk-Informed, Performance-based Approach for Non-Light-Water Reactors.
.......7 6 Guidance Paper NEI 18-04.
............86 7 8 Draft Regulatory Guide DG-1353 and 9 SECY-18-00XX 233 10 Public Comment . . . . . . . . . . . . . . . . . 262 Adjourn.....................265 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 4 1 P R O C E E D I N G S 2 8:30 a.m.3 ACTING CHAIRMAN CORRADINI:
Okay, why 4 don't we get started? G ood morning. The meeting will 5 come to order.
6 This is a meeting of the Advisory 7 Committee o n Reactor Safeguards Subcommittee on Future 8 Plant Designs.
9 My name is Mike Corradini. I'm chairing 10 this meeting for Dennis B l e y w ho is chairman o f the 11 Future Plant Designs Subcommittee.
12 ACRS members in attendance are Charles 13 Brown, Ron Ballinger, Jose March-Leuba, Dick Skillman, 14 Walt Kirchner, Joy Rempe and Vesna Dimitrijevic.
15 Dennis B ley as I said is o n the 16 teleconference l i n e a n d he'll let us know if h e has 17 questions through one of the members since we're on an 18 open line that is muted.
19 Girija S hukla, the ACRS staff, is the 20 designated federal official for today's meeting.
21 The purpose o f today's meeting is to 22 review the w orking d rafts of the N R C staff and NEI 23 guidance documents to implement a t echnology-inclusive 24 r isk-informed performance-ba s e d a p p r o a c h f o r a p p r o v i n g 25 non-light-water reactors also known as the licensing NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 5 1 modernization project.
2 The subcommittee will g ather information, 3 analyze relevant issues and facts and formulate 4 proposed positions and a ctions as appropriate for 5 consideration by the full committee.
6 It is scheduled t he full c ommittee to 7 address this m atter in the December full committee 8 meeting.9 The ACRS was established by statute and is 10 governed by the Federal A d v i sory Committee Act or 11 F A C A. That m eans t hat the committee can only spe a k 12 through its published letter reports.
13 We hold meetings to gather information to 14 support our deliberations.
Interested parties who 15 wish to p rovide comments can contact our offices 16 requesting time after the Federal Register notice of 17 the meeting is published.
18 That said, we also set a s i de time for 19 extemporaneous c omments from members of the public 20 attending or listening to ou r meetings.
Written 21 comments are also welcome.
22 The ACRS section of the U.S. NRC's public 23 website provides our charter, bylaws, letter reports 24 and full transcripts of all o ur full and subcommittee 25 meetings including all slides presented at the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 6 1 meetings.2 Detailed proceedings f or conduct of the 3 ACRS m eetings was previously published in t he Federal 4 Register on October 4, 2018. The meeting is open to 5 public a ttendance and we have received no requests for 6 time to m ake o ral statements.
However, time h as been 7 allotted in today's agenda in case of extemporaneous 8 comments.9 Today's meeting is being held i n telephone 10 bridge line allowing participation of the p ublic over 11 t h e phone. A transcript of today's m eeting is al s o 12 being kept.
13 Therefore we request t hat meeting 14 participants on the bridge line when they are called 15 upon to identify themselves when they s peak a nd to 16 speak with sufficient clarity and volume so they can 17 be readily heard.
18 Participants in t he meeting r oom s hall 19 also use the microphones located throughout the 20 meeting room when addressing the subcommittee.
21 I'll note that w e h ave a challenge i n our 22 new c onference setting so w e'll b e looking for the 23 presenters if they have experts they need to bring to 24 the mike to come over to the other side and identify 25 themselves.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 7 1 At this time I'll a sk th e a ttendees to 2 please silence all cell phones and other d evices that 3 make noises to minimize disruptions.
4 Also I remind the speakers in front of the 5 table to turn on the microphone which is i ndicated by 6 the illuminated green light when speaking and 7 otherwise turn off the microphone when not speaking.
8 We'll proceed with the meeting and I'll 9 call on John Segala, chief of the Advanced Reactor and 10 Policy Branch of the Office o f NRO to make our opening 11 comments. John.
12 MR. SEGALA: Thank you, Dr. Corradini, and 13 the other committee members. We're p leased to be here 14 today to discuss the l icensing modernization project.15 The N RC staff sees this as a key aspect of 16 licensing and risk-informing advanced reactors.
17 I wanted to step back for a moment and 18 just provide some context of where we've been. Back 19 in April 2017 industry submitted the first of four 20 white papers on the licensing modernization project.
21 We reviewed those, p rovided feedback.
22 They then consolidated those into an NEI d ocument 18-23 04. We presented that to the ACRS committee in June 24 of 2018. We also gave the committee some initial 25 thinking on the development of a regulatory guide to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 8 1 potentially endorse the NEI document.
2 We took the feedback we received from 3 ACRS. We developed a working draft of the r egulatory 4 guide a nd an associated commission p a per. So t oday 5 we're g o i n g to be presenting an overview of the NEI 6 document, the commission paper and the draft guide.
7 We're looking for the committee to write 8 us a letter on the commission paper. And a gain we 9 look forward to the i nsights and the feedback that the 10 ACRS provides us today. With t hat I c an turn it over 11 to Bill Reckley.
12 MR. RECKLEY: Thank you, J ohn. S o the 13 order of t he presentation today w ill be we'll provide 14 a little b ackground to answer one specific request 15 from the ACRS. We're going to spend the first few 16 minutes talking about the enhanced safety focused 17 review approach which is -- I an Jung will go i nto. 18 But that's primarily f or light water small modular 19 reactors.20 But we've referenced it in the licensing 21 modernization project discussions a s kind o f a 22 stepping stone to where we're ending up. So it fits 23 in well with the background.
24 Then I'll talk about the o verall non-25 light-water r eactor p rogram, j ust a summary because NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 9 1 again we've been to the subcommittee a couple of t imes 2 in the context of the program and then in the context 3 of t he advanced reactor design c riter i a a n d the 4 functional containment performance criteria paper.
5 Then I'll give a s ummary or h igh-level 6 overview of t he technology-inclusive methodology.
7 And then after the break t h e industry group, NEI, 8 Southern Company and other participants in the 9 industry effort will go over the licensing 10 modernization and in particular the guidance that's 11 now in the draft, the working draft of NEI 18-04.
12 And then we'll close the d ay this 13 afternoon with a discussion o f t he specifics o f t he 14 SECY paper which John mentioned.
We'll be asking for 15 a letter on that paper.
16 And the draft r egulatory guide and the 17 ACRS can decide on whether they want to weigh in on 18 the draft guide or wait until publi c c omments are 19 received a nd w e move to the next step to finalize the 20 guide.21 So with that I'll turn it over to Ian.
22 MR. JUNG: G ood morning, C hairman and 23 committee members. My name is Ian Jung. I recently 24 took a p osition as a senior reliability and risk 25 analyst within the same division as J ohn and Bill are NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 10 1 working.2 I've been with the INC as a branch chief 3 for chapter 7. Some of you have h eard about design 4 specific review standards fo r chapter 7 which is 5 somewhat consistent with some o f the framework w e are 6 talking about from instrumentation control systems. 7 So I bring some background from a technical a spects of 8 it.9 The reason I'm here is to specifically 10 talk about enhanced safety focused review approach.
11 Some of t he members may not have appreciation for some 12 of the background.
13 So, Mr. Ray asked for specifically o n this 14 topic. So I want to spend a few minutes on overview 15 of the enhanced safety f ocused review approach and its 16 potential r elationship with t he LMP, licensing 17 modernization project.
18 I think t here's some relationship and I 19 want to briefly touch upon that.
20 So, this particular approach i s a staff's 21 approach for NuScale specific r eview. T he intent was 22 to f o c u s o n safety. I'm going to go over that a 23 little bit more.
24 This particular approach i s about the 25 tools and stra t e g ies for s taff to use in defining NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 11 1 scope and depth of the r eview w hich can h ave an impact 2 on efficiency and effectiveness of the staff reviews.3 This is a particular a pproach i s a 4 companion to NUREG-0800 SRP, s tandard review p lan, 5 introduction part 2. I believe the committee has been 6 briefed on t his particular topic on S RP u pdate related 7 to small modular reactor reviews.
8 And also I think staff h as briefed the 9 committee on design specific review standards and in 10 particular chapter 7 was w i t h t he committee several 11 t i mes for m Power as well as NuScale design specif i c 12 review s tandards where the whole SRP has been 13 reformatted and restructured to be consistent with the 14 fundamental design principles focus that Mr. Brown has 15 working with us. We have a very p ositive letter on 16 it.17 The whole approach is intended to be used 18 during both pre-application and during actual review 19 process. And pre-application and collaboration with 20 potential applicant is criti c al in success o f this 21 particular approach. Next slide.
22 So the overall objective of this enhanced 23 safety focused review approach is to increase 24 effectiveness and efficiency for staff reviews t o meet 25 the c ustomer's needs. Also to m eet the statutory NRC NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 12 1 mission of the regional n otional (phonetic) safety 2 finding in an efficient manner.
3 This particular a pproach is also 4 Commission directed.
There are a c ouple o f documents 5 that I just -- I don't w ant to go over that but bottom 6 line is that Commission told t h e s t a ff to focus its 7 review and resources on -- to risk-significant SSCs, 8 structures, systems and components and other aspects 9 of the design that contribute most to safety.
10 I th i nk on this topic related to SRP 11 introduction part 2 a s well as the design specific 12 review standard and t his enhanced safety focused 13 review approach there w ere p resentations to the 14 committee several times. In addition for chapter 7 I 15 think we came to the committee multiple times to deal 16 with the chapter 7 design specific review standards.
17 Next slide.
18 So I j ust w ant to high l i g h t there are 19 multiple tools and activities that went on to help the 20 staff with the NuScale review. And one of the review 21 tools that we provided to the s taff and h ad a multiple 22 trainin g a nd other sessions is this particular tool 23 that providing sort of the table and l o g i c that 24 considers v arious elements o f the -- v arious elements 25 that could have an impact o n the staff r eview's safety NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 13 1 significance or risk significance.
2 This whole A1 A2, B1 B2 a pproach. A1, A2 3 refers to safety-related risk significant or not risk 4 significant.
B1, B2 correspon ds to the n on-safety 5 portion of that.
6 Of course complying w ith the specific 7 regulations, how to meet those. Novel nature of the 8 design. NuScale had a multiple areas of novel design.9 Also related to interaction b etween safety 10 and non-safety as well a s the safety interactions that 11 could have dependencies that could have an impact on 12 safety or risk.
13 Unique licensing approach.
The NuScale 14 had some areas where exemptions are made as well as in 15 other areas. Of course the Regulatory Guide 1.174 has 16 elements in safety margin and defense-in-depth.
17 Of c ourse how to d eal with the operational 18 programs a nd additional risk insights to be 19 considered.
20 Through these considerations without 21 dealing some o f the issues in a p iecemeal I think the 22 intent w a s to have the staff members consider t hese 23 various elements in deciding the scope and the depth 24 of the staff reviews. Next slide.
25 This is my final slide. So status and NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 14 1 future. This particular approach was applied during 2 the pre-application and during the early reviews.
3 We had various a spects o f it that not all 4 place, all disciplines used th is approach based on 5 uniqueness of each discipline or the timing o f the 6 reviews.7 We had successes. Chapter 7 is one that 8 I keep referring to. But there are other areas that 9 staff made a conscious decision on considering various 10 elements in deciding t he scope a nd d e p t h of the 11 reviews.12 The staff i s currently developing lessons 13 learned. We expect to have a memo developed t o s hare 14 with the office and in other places.
15 We believe that this particular approach 16 can be used in the future including advanced reactor 17 reviews. We are coordinating with Bill's branch. I 18 think there's more to come.
19 The nexus of t hat particular approach I'm 20 just discussing with the f uture licensing 21 modernization pr o ject is that -- most of today's 22 d i s c ussion is on the f ramework approach a nd f o r 23 industries to use and as an endorsement of it.
24 B u t I think there's going to be anoth e r 25 piece r elated to what staff c a n review, what depth, NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 15 1 what scope, efficient and effectiveness of the staff 2 revi e w. So I think standard review plan or this 3 particular enhanced safety-focused review approach I 4 think staff has been discussing how t o g o about d oing 5 that part of the piece.
6 But we are following this p articular 7 licensing modernization project very carefully as we 8 deal with the staff portion of the review.
9 Overall I think the underlying concept of 10 the enhanced safety-focused r eview a nd -- is 11 consistent with the agency's r isk-informed and 12 performance-based approach.
That's the e n d o f my 13 presentation. Any questions or comments?
14 ACTING CHAIRMAN CORRADINI: Questions by 15 the committee?
16 MEMBER R EMPE: So m y understanding
--17 Harold's n ot here, but my understanding h i s concern 18 was that some of the required content that has to be 19 submitted would be reduced or would b e eliminated from 20 this Reg Guide 1.206 is why he asked us to discuss 21 this at this meeting today. Which is reasonable.
22 But I guess he also was interested in how 23 this w ould affect how ACRS i nteracts on such reviews. 24 You c an weigh in here, Mike, but with w hat w e saw with 25 NuScale I thought ACRS was pretty much kept onboard.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 16 1 There w ere interactions with A CRS to make 2 sure we w ere aware of w here you w ere focusing on. Is 3 that the intent? Like if y ou're going to say w ell, 4 certain t hings don't have t o be included a s mandatory 5 anymore in the submittals based on your interactions 6 with the designer you would hav e s o m e w ay of always 7 coming t o ACRS and interacting with u s so we 8 understood why certain components would not be 9 required.10 MR. JUNG: So I think the question is much 11 broader than just enhanced safety-focused review 12 approach.
This particular approach is m ore of a 13 staff's review approach based on what's expected, the 14 information that is expected to be submitted through 15 other vehicles.
16 Regulatory Guide 1.206 is one of t hose 17 attempts.
But I think we r ecognize that f or advanced 18 reactors in particular Regulatory Guide 1.206 update 19 I don't think in my understanding i s it d o e s not 20 r e a l ly -- we didn't c reate Regulatory 1.206 to be 21 completely up to date associated with the additional 22 approach.23 But I think I expect tha t, I mentioned 24 about the standard review plan being updated for the 25 future. I think that's a vehicle that I think the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 17 1 committee has the opportunity to discuss that.
2 ACTING CHAIRMAN CORRADINI:
I guess I want 3 to just stay on this slide for a minute to make sure 4 I understand.
5 So to put it in the simplest terms, is the 6 LMP that we're going to hear about throughout the day 7 today a natural outgrowth of what you d id for the 8 enhanced safety-focused review for NuScale?
9 MR. RECKLEY: This is Bill. We certainly 10 are taking the lessons learned f rom t h a t and in 11 previous discussions with both the industry and with 12 the ACRS we talk about bringing the enhanced safety-13 focused review approach forward.
14 One primary difference to keep in mind is 15 that for light waters which i s Reg Gui d e 1.206 and 16 also the S RP this is an o ver l a y o f that existing 17 framework to say w here additions and m aybe 18 subtractions should come in the staff's focus.
19 As w e go forward w ith the non-lights w e're 20 g o ing to take some of t hese c oncepts like t h e 21 consideration of operational p rograms, the focus on 22 safety and so forth, key concepts, but as opposed to 23 overlaying it on that framework we're going to build 24 a framework with those concepts embedded if you w ill. 25 We're not taking the SRP and sc a l i ng it NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 18 1 back f or non-lights.
We're tweaking it for non-2 lights. We're planning on building this framework 3 which you can see the first step in what we're going 4 to talk a bout today on how to build it basically from 5 the ground up.
6 ACTING CHAIRMAN CORRADINI:
Okay. S o let 7 me say it back to you so I've g ot it right. So you're 8 looking at really assemb ling an SRP that is 9 technology-inclusive.
10 MR. RECKLEY: R ight. Which is why it ends 11 up looking more like a methodology than a list. Most 12 of the guidance for li g h t water reactors are lists. 13 There's specific items --
14 ACTING CHAIRMAN CORRADINI: That have to 15 be looked at, that have to be reviewed.
16 MR. RECKLEY: Right. Wh ereas for what 17 we're going to talk about today since it's technology-18 inclusive it's more of a methodology that any designer 19 for any technology can u se t o construct a n application 20 and then as Ian s aid we'll have companion guidance for 21 how we're going to do reviews.
22 But it won't look -- our current p lans are 23 it won't look so much like a list.
24 ACTING CHAIRMAN CORRADINI:
To do things.25 MR. RECKLEY: Right.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 19 1 MS. CUBBAGE: I'm seeing Joy's looking a 2 little confused still. This is Amy Cubbage, NRO.
3 So b asically in a nutshell the NuScale 4 application was generally developed based on the way 5 applicat ions have always been developed.
And then 6 ESFRA was a way for t he staff to in certain areas with 7 more or less emphasis.
8 This will develop a different t ype of 9 application from the bottom up. LMP.
10 MEMBER R E MPE: I think I understand.
And 11 again, I'm trying to i nterpr e t a l s o what Harold 12 conveyed to us. So ba s i c a l ly you'll have a process 13 and designer X will come in and they may only need 3 14 of the 10 components that were on the old list.
15 And somewhere t he staff will interact with 16 him and concur. A nd then Harold was concerned how 17 will ACRS fit into this p rocess. And a t that p oint 18 you'll intera c t w i th us a nd we'll say y es, we a gree 19 with you, or no, we don't agree with you, you need to 20 include another component.
Is that kind of -- are we 21 talking the same thing?
22 ACTING CHAIRMAN CORRADINI:
But let me 23 just back up a step because I think Joy said it very 24 well. I think Dennis had some o t h er q uestions.
25 Dennis.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 20 1 CHAIRMAN BLEY: Yes.
2 ACTING CHAIRMAN CORRADINI: Did you want 3 to ask your question?
4 CHAIRMAN BLEY: Yes, I had a comment and 5 a questi o n. The comment g oes back to Joy speaking 6 about what Harold was concerned about.
7 And Reg Guide 1.206 rev 1 states that the 8 technical i n formation that used to be in 1.206 at 9 least the w ay I r ead it is going to s how up in interim 10 staff guidance or some other form in a while. And I 11 guess the question on t hat is what's a while. Is that 12 going to be available a bout the same t ime as t his reg 13 guide or what are people supposed to do.
14 ACTING CHAIRMAN CORRADINI: There's some 15 background noise on the line so whoever's out there is 16 going to have to mute themselves. Bill, did you get 17 it?18 MR. REC K L E Y: Yes. We are going to 19 continue.
W e're mixing apples a nd or a n g es a little 20 bit as we bring in the non-light discussions and Reg 21 Guide 1.206 update which w ill c ontinue to be for l ight 22 water reactors. So just want to keep that. There's 23 two things. They're related bu t t here a re separate 24 activities.
25 There are activities underway to provide NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 21 1 as Ian mentioned an update and f urther risk i nform the 2 SRP. Those things will take a little while. I d on't 3 think they are intended to be companions to t he update 4 to Reg Guide 1.206.
5 Ian, do you have any more or maybe J o hn 6 Monninger? No.
7 CHAIRMAN BLEY: I'm a little confused by 8 that because i n section B of 1.206 it actually points 9 to the fact t hat thi s will be reflected in interim 10 staf f guidance by NUREG o r some other m anagement 11 document to pick up that technical information that's 12 disappearing from -- s o w e will leave t hat on the 13 table if nobody there wants to talk to it.
14 M S. CUBBAGE: So you mean, is that i n 15 general or what was that in the context of ESFRA? I 16 think in g eneral, and please, John Monninger, correct 17 me if I'm wrong, I think there is an attempt w ith the 18 new version of Reg Guide 1.206 to put more of the 19 guidance into the SRP in the future and less i n Reg 20 Guide 1.206. But John is coming to the mike.
21 CHAIRMAN BLEY: Okay.
22 MR. MONNINGER:
Good mor n ing. T his is 23 J o h n Monninger from the s taff. I'm the director , 24 Division of Safety Systems, Risk Assessment and 25 Advanced Reactors.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 22 1 So I think it's a good discussion and with 2 the staff in approaching the revision s o f Reg G uide 3 1.206 and then the SRP they recognize that there was 4 tremendous overlap between the two.
5 So the intent was to the extent possible 6 could you pull out the technical details out o f 1.206 7 and put the technical acceptance criteria within the 8 SRP.9 However, i t w i ll take a while to update 10 the SRP so the staff i s considering how b est to do 11 that and I think that's t he concept of how the ISGs 12 were brought into play. 1.206 w as meant to be just 13 the f ormat and content of the applications and the 14 real technical criteria the staff is trying to focus 15 that within the SRP.
16 The problem i s when we had technical 17 criteria in t wo d ifferent documents when new insights, 18 lessons learn e d , you know, it was difficult t o keep 19 the t wo documents consistent so t he thought w as to 20 focus all the criteria within the SRP.
21 I'm not up to speed on the details of the 22 schedule for the ISGs but during lunch we could run it 23 down with the appropriate staff and chit chat in the 24 afternoon session.
25 CHAIRMAN BLEY: I think that's great. I NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 23 1 know 1.206 i sn't the focus for today, but sinc e we 2 mentioned a few things about it I may -- comment.
3 It seems to me this has g one the wrong way 4 to p roviding more guidance tha n j ust how to put 5 together the application for people who want to come 6 and talk with the staff early and do the kind of 7 things that have been evolving over the last year or 8 two. Seems pretty thorough on that.
9 The o t h e r point is although it is for 10 light water reactors right in the second paragraph the 11 staff says they also consider this to apply to other 12 types of power reactors.
So I would agree with t hat.13 It's kind of slipped off o f just being an 14 LWR document, right, even if it's introductory steps. 15 That's about all from me on this, Mike.
16 ACTING CHAIRMAN CORRADINI:
So let me try 17 one more time to simplify for m e. Maybe eve r y body 18 else gets it. I'm still -- so i t's fair to say t here 19 will be a 1.206 prime in some fashion f o r non-light 20 water reactors and there will be a standard review 21 plan prime.
22 Or will it be just -- because you u se the 23 word overlay but I sense it's m o r e t han a n overlay. 24 It's almost like a buildup from scratch. Which of 25 those two is it? I'm s till -- I'm not c ompletely NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 24 1 clear.2 MR. RECKLEY: W hat we're going to do as we 3 go f orward you have NEI 18-04 and Draft Guide 1353 4 which is a first step.
5 We're going to t hen continue to work with 6 the industry to see what other guidance is needed. If 7 the feedb a c k is more d etail is needed on how to 8 construct an a pplication then we'll focus on t hat. If 9 it is on how to do a p articular area w ithin NEI 18-04, 10 maybe one of the analytical discussions that w e're 11 going to have later today and the d evelopers t hink 12 they need more guidance in that a rea then we'll f ocus 13 on that.14 ACTING CHAIRMAN CORRADINI:
Okay. That 15 helps. Thank you.
16 MEMBER K I R C H NER: Mike, may I a sk a 17 question?
S o Bill or John or whoever, I know w e'll 18 hear about this later toda y. I'm just a little 19 concerned maybe about reconciling all these different 20 approaches.
21 I'm looking right now on m y computer at 10 22 CFR 5 0.34 a nd I'm wondering why you wouldn't s tart 23 there in a technology-inclusive manner and proceed. 24 Because you loop back to that later in your -- in the 25 LMP.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 25 1 So I'm just somewhat concerned about how 2 all these different approaches get reconciled and 3 which ones t a ke precedence in t erms of establishing 4 some certainty.
5 You're l ooking for efficiency and 6 effectiveness in the regulatory proc e ss, but I see 7 c o m plexity being b uilt. But m aybe I'm n o t 8 appreciative of how you see this being str eamlined 9 when you're done. S o maybe it's a discussion for 10 later in the day but just put that marker down.
11 MS. CUBBAGE: Maybe I could just offer --12 again, this is Amy Cubbage -- that we brought in the 13 ask for discussion at the beginning just specifically 14 to a d dress M ember Ray's q uestion relative to the 15 committee's review of Reg Guide 1.206.
16 And really other than the fact t hat t here 17 are some principles in c ommon we're n ot a pplying E SFRA 18 in t he future for non-LWRs.
That's something that was 19 developed f or the NuScale review, maybe used again if 20 the opport u n i t y arose, b ut we see the L MP as really 21 the way we're going for the future for the non-LWRs to 22 develop and bake in the p rocess from the b eginning to 23 be risk-informed, performance-based and technology-24 inclusive.
25 It's difficult for going forward with a NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 26 1 non-LWR to start with the standard review p lan that's 2 largely light water reactor-centric and also i sn't 3 even applicable t o the non-LWRs.
So this process you 4 see in the draft guide is r eally w h e r e we're headed 5 for t he non-LWRs and I don't want there to be left any 6 confusion on the ESFRA.
7 MEMBER KIRCHNER:
Then let me be specific 8 because you have slides up t here that suggest 9 otherwise.
W hat lessons l earned have you so far 10 derived from this process and what is being c onsidered 11 in coordination with LMP?
12 MR. JUNG: In terms of l essons learned 13 there's a draft report i n there so I don't want to go 14 too f ar w ith that. I sort o f briefly mentioned t hat. 15 Because of the timing and uniqueness of 16 the discipline applying I think n ot e verybody, not all 17 the disciplines w ere able to execute that in a manner 18 that was originally intended.
19 But I think the underlying concept of 20 being able to -- the linkage t hat I was r eferring to, 21 there's lessons learned that Bill was also mentioning.
22 There's some e lements that a re applicable to -- it is 23 a generic be c a use if you l ook at the definition of 24 risk-informed and performance-based regulation the 25 staff's effort focusing on most safety significance of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 27 1 it. The underlying concepts are the same.
2 B u t I think as we apply s ome of t hese 3 concepts f o r the future I see some valuable lessons 4 that can be shared in terms of how w e approach it. 5 But specific elements of what documents to be 6 submitted and how the specific regulations that u nder 7 Part 50 specific, those individual regulations, how to 8 deal with that as well as the staff guidance, I t hink 9 the message is somewhat clear t hat staff needs to work 10 on and work with industry to come up with something.
11 But I think the underlying safety issues 12 and the elements, we have a great number of s taff 13 m embers who can use the current f ramework.
I t h i n k 14 the message from Am y a n d Bill is t hat perhaps t here 15 are new way of doing business in that regard.
16 MR. MON N I N GER: If I could just a dd two 17 comments on lessons learned. This is John Monninger 18 from the staff.
19 So I think it's -- I thi n k ESFRA was a 20 very important worthwhile effort. I think we really 21 had two big challenges.
22 One is th e d esign o f NuScale. It's a 23 light water reactor design, compliance with the 24 current requirements, compliance with the current 25 SRPs. S o we tried to come i n w i th an approach that NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 28 1 would then almost afterwards sort of dissect that. So 2 that was very difficult to then apply in terms of the 3 design, what to focus on, what should be submitted.
4 As a matter of fact it didn't even impact 5 what was s ubmitted on the NuScale design. So the 6 NuScale design, the E SFRA appro a c h had no impact on 7 the actual submittal.
8 So we had all th e existing SRPs, the 9 e n t i re application come in from NuScale and t hen to 10 tell the staff to focus more heavily on these areas, 11 not to focus as much on these areas.
12 It really r epresented some internal 13 challenges with how we proceeded.
14 I n addition t o that the DSRSs that w e 15 developed really didn't benefit from a risk-informed 16 approach i n development of t he DSRSs. Those had to a 17 large extent begin prior to a lot of the E SFRA 18 efforts.19 The others I think in terms of just change 20 management within the NRC staff. T he real E SFRA 21 efforts and focus probably occurred about a year, year 22 and a half prior to the a pplication coming in. So it 23 was difficult in terms o f our roll-out a nd our buy-in 24 on that.25 Here we're trying to build it in up f ront NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 29 1 well in advan c e o f t he applications coming i n. The 2 effort is actually being led by and run b y the 3 projects, the licensing staff.
4 S o t h e whole issue of -- to me it's two 5 things. It's one in terms of the challenges w ith the 6 NRC f or change management a nd here we're trying to 7 bake in the process from the ground up.
8 And the o ther is in t erms of the applicant 9 and the design and the material coming in. Have the 10 material c oming in and th e a pproach consistent with 11 h ow we intend to review it. So I think i t's t w o 12 things.13 A lo t of it i s change management and 14 execution within the staff and the other is in terms 15 of the actual application of material and expectations 16 on the applicant. They would be the two top lessons 17 learned that I would throw out there.
18 CHAIRMAN BLEY: W hile John's still up 19 there can I slip something in?
20 ACTING CHAIRMAN CORRADINI:
Sure. W e will 21 need to move on.
22 CHAIRMAN BLEY: The safety-focused review 23 approach is actually c alled out in Reg Guide 1.206 rev 24 1. I'm just a little curious, John. And this is not 25 terribly relevant for s afety, b ut your g roup spent an NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 30 1 awful lot of time coming up with this phrase safety-2 focu s e d r eview. And n ow suddenly it seems to be 3 replaced by an incomprehensible a cronym. I just 4 wonder what led to that. And I'm off.
5 A C T I N G C H A I R M A N C O R R A D I N I: 6 Incomprehensible acronym. That's what he said.
7 MR. MONNINGER:
This is John M onninger.
8 If E SFRA is the incomprehensible acronym. So I t hink 9 that really represents some internal challenges with 10 change management.
11 Originally the team working on it talked 12 about a risk-informed approach.
There are some optics 13 within the agency about risk-informed, risk-based, a 14 reliance upon risk.
15 So really risk and safety, we view it as 16 being one, hand in h and the same t hing. However, 17 there ar e s ome internal challenges there so we 18 deli b erately -- it's the same approach for r isk-19 informed performance-based approach but in an attempt 20 to address challenges internally with change 21 management we used the incomprehensible acronym.
22 CHAIRMAN BLEY: Thank you.
23 ACTING CHAIRMAN CORRADINI:
Okay, onward.24 MR. RECKLEY: Okay. And a s we go through 25 you can judge to the deg r e e that we've tried to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 31 1 incorporate some of those concepts into what w e're 2 doing now f or non-light water reactors as we s hift 3 over to the primary focus of today.
4 We've been before the subcommittee a 5 couple of times a s I mentioned to talk about the 6 overall program, our strategy, a nd our implementation 7 and action plans.
8 One goal that we'v e had a ll along is 9 wherever possible to b e t echnology-inclusive.
And 10 that kind of drives a lot of the discussion today as 11 to why we lean towards methodologies.
12 We h ad t he s ame discussion when w e were 13 before y ou talking a bout the functional containment 14 p e r formance criteria, t hat i t is more of a 15 methodology. The performance criteria is not a leak 16 rate from a structure, it's a methodology on how well 17 a design using whatever combination of barri ers is 18 able to retain the radioactive material.
19 So just a quick s ummary. The 20 implementa t i o n and action plans that we've h ad from 21 the beginning is divided i nto six strategies, building 22 the s taff's knowledge, developing the tools like 23 computer codes and the ACRS has had a recent meeting 24 on that topic with DOE and the laboratories.
25 Strategy three is to develop a licensing NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 32 1 framework.
Strategy four is to w o r k with the 2 standards development organizations, A SME, ANS to 3 develop consensus codes and standards.
4 Strategy five is the resolution of policy 5 issues. And again the ACRS has been involved.
The 6 proposed rulemaking o n emergency planning, SECY 18-7 103, that's going up to the Commission.
The 8 functional containment performance criteria, SECY 18-9 96 recently went up to the Commission.
10 Strategy six is communications.
And then 11 down at the bottom I have just a couple of points that 12 the staff is trying t o remain aware of p otential f irst 13 movers to see if we n eed to accelerate an activity or 14 change our focus if a particular design or t echnology 15 is moving ahead of the others.
16 And then a recent topic that's come up in 17 the context of t h e D efense Authorization Act and 18 elsewhere is micro reactors and the possible 19 development and deployment of those technologies.
20 But the focus today is on the last block 21 under the licensing framework, the licensing 22 modernization project.
23 ACTING CHAIRMAN CORRADINI:
Let me ask 24 about the purple circle. This is still an option for 25 the industry.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 33 1 MR. RECKLEY: Yes.
2 ACTING CHAIRMAN CORRADINI:
So, not to 3 take us ba c k. If they choose not to u se the option 4 they would e ssentially have t o g o o n a case-by-case 5 exemption under a light water reactor set framework.
6 MR. RECKLEY: Yes, or develop something 7 totally on their own.
8 ACTING CHAIRMAN CORRADINI: Okay, that's 9 what I thought. I wanted to make sure. Thank you.
10 CHAIRMAN BLEY: This is D ennis. Question 11 for Bill. Actually a comment. When this all f irst 12 star t e d we really pushed for the staff to focus on 13 strategies three and f ive a nd I think that's been done 14 pretty well.
15 As you've pointed out all of these pieces 16 are r eally tied together.
H ave you heard anything 17 back fro m t he Commission yet on t he f unctional 18 containment paper?
19 MR. RECKLEY: Not yet.
20 CHAIRMAN BLEY: Okay. Because without 21 that I think all of this stuff starts to unravel.
22 MR. RECKLE Y: Yes, w e agree, and that's 23 why we wante d t o s e n d it up first. And what w e've 24 explained to a nyone who asks is if you have any f ixed 25-- well, I'll g e t into that in the next s lide NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 34 1 actually. It's a good one to just lead into.
2 ACTING CHAIRMAN CORRADINI:
But before you 3 do. So let's just stay on t he policy list because 4 Dennis picked one. What i s the s tatus of the others? 5 Or should we -- or i s it that the f unctional 6 containment is probably the leading policy issue that 7 needs to be settled? I see a couple of others there 8 that would concern me to be clear.
9 MR. RECKLEY: Right. S o w hat w e're 10 currently working o n, on t h e f irst one, siting near 11 populat e d centers. We have guidance a nd t he most 12 restrictive part of th e g u i dance is that we look at 13 population density out to 20 m iles. And t he guidance 14 is 500 people per square mile out to 20 miles.
15 For the deployment when we talk t o D OE or 16 the laboratories or others that's a p articular 17 challenge.
And so we're looking to see if that is an 18 appropriate factor for s maller reactors or r eactors of 19 different technologies.
20 We're currently working on that. We 21 issued a preliminary white paper not with a proposal 22 but just kind of to frame the issue. And w e're 23 currently working through our p eriodic stakeholder 24 meet i n g s to undertake that. And we have a contract 25 with a laborator y to help u s evaluate p articular NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 35 1 possible options.
2 In terms of i nsurance, the Price-Anderson 3 Act, we t he NRC, the agency owes a report to Congress 4 in 2021. We plan to have a s ection on advanced 5 reactors to s a y whether we think the current 6 requirements are fine, whether we think they s hould be 7 changed o r w hether we think more s tudy would be 8 warranted in terms of what insurance is required for 9 non-light water reactors.
So that's an e arly 10 activity.
We have it identified but we've really not 11 done too much yet.
12 Consequence-based security.
That SECY 13 paper is identified there, 18-76. That's curr e n t ly 14 befo r e the C ommission where the staff proposed a 15 rulemaking somewhat similar t o t he EP r ulem a k i ng to 16 say we w ould do a performance or consequence-based 17 approach to security and if certain performance 18 measures could be met requirements such as the number 19 of armed responders might be revised.
20 And then we're always l o o king to see if 21 there are other policy issues or key t echnical issues 22 that are identified that we w ould a d d to t he l ist. 23 There are others that we didn't list here. We just 24 listed the primary ones that we're currently working 25 on.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 36 1 ACTING CHAIRMAN CORRADINI: Thank you.
2 MR. RECKLEY: S o , one o f the goals that 3 the NRC staff has in any case is to try to look at 4 this in an integrated fashion. And as Dr. Bley was 5 mentioni ng these things are all interrelated.
And 6 that makes i t difficult because f o r t he light w ater 7 reactors much of it was p ut in place in t he fifties 8 and sixties and then it was added and revised over the 9 d e c a d e s in various areas to say what are the events 10 that need to be addressed , w h a t are the c ontrols or 11 barriers to address those threats or events, and what 12 potential measures might be taken to m i t i g a te the 13 consequences if there's a release.
14 So this bow tie d ia g r a m was used in the 15 functional containment paper just to k ind of lay out. 16 It's got i t s limitations as an assessment tool 17 per h a p s, but it's a g ood representation of how to 18 consider a number of factors as y ou're looking at the 19 overall program.
20 So going back to that policy list y ou can 21 see I've just -- I resist all along t rying to put 22 specific things on the blocks in the generic diagram 23 in terms o f w hat are the b arriers or controls for 24 different technologies.
25 But just as an example you can put up some NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 37 1 and for example E P, emergency planning, the e vacuation 2 of people i s usually c onsidered t he last step, the 3 last mitigation measure that if you h a v e to you 4 reserve the r ight to m ove the people o ut of the way if 5 you're u nable to keep the radionuclides from b eing 6 released.7 So you s ee we h ave an activity in that 8 regard. I nsurance and liability and environmental 9 reviews I mentioned as well as siting. T hat is a key 10 factor not only in terms of things like external 11 e v e n ts m aybe on the prevention side but it's also a 12 measure that's used o n t h e mitigation side. That's 13 why you have population d ensity criteria for example.14 And then functional c ontainment.
The 15 containment function goes beyond just the d esign b asis 16 events, traditional design basis events, and goes into 17 the beyond design basis events if you d o have in l ight 18 water r eactor s a core damage a ccident or what w e've 19 defined for n on-light w ater reactors the top l evel 20 event b ein g a plant damage state with the unplanned 21 movement of radionuclides. You need to come up with 22 terminology like that because some reactor designs 23 have a planned movement of radionuclides in the form 24 of molten salt going around the coolant system.
25 So, that is kind of what we were looking NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 38 1 at and trying to make sure that as we go forward and 2 look at any particular area that we are also looking 3 at the i ntegrated a nd how the whole p icture fits 4 together.5 And so for example in the emergency 6 planning proposed rulemaking it points back for non-7 light water reactors to the LMP in terms of where are 8 you going to identify the events that y ou have to 9 assume in o rder to assess whether the dose remains 10 less than the protective action g uides and perhaps you 11 c a n justify a smaller emergency p lanning zone. A n d 12 I'll get to that in a second.
13 So, whereas that goes beyond the immediate 14 scope of licensing modernization there is a 15 relationship there a nd the staff is trying to make 16 sure that we remain c ognizant o f a l l of t hese 17 different p roposals and that they all fit t ogether in 18 the end to make an integrated approach.
19 As if that figure wasn't complicated and 20 busy --21 ACTING CHAIRMAN CORRADINI:
I congratulate 22 you on the denseness of whatever that is.
23 MR. RECKLEY: So, one of the challenges as 24 you change technologies is the tendency, and we face 25 this all the time, and I do it myself, everybody does NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 39 1 it, t o start where you're comfortable w hich i s for 2 example we talked earlier of NUREG-800 and so forth.
3 And say okay, we're going to apply it to 4 something different now and how does it change. The 5 more we'v e l ooked at that t he more we conclude that 6 you're better off to start with First Principles and 7 borrow from NUREG-800 w here it's applicable but d on't 8 become so wed to it that i t a ctually hampers you g oing 9 forward.10 So w h a t t his slide w hich is included in 11 the working draft of the SECY paper i s t r y i n g to 12 convey is the three fundamental s afety functions with 13 the highest level safety function being the retention 14 of fission products o r the retention of radioactive 15 materials.
16 And that can b e modeled through just 17 basically a set of barriers or c ontrols in saying how 18 well can that barrier a ttenuate the radioactive 19 materials o r the release o f radiation or another form 20 of the e quation what's the r elease fraction across 21 each barrier as you go through the process.
22 And one of the things that you'll see is 23 a different reliance on different barriers f or the 24 different technologies.
And so w e thought it was 25 important to start w ith again high-level F irst NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 40 1 Principle kind of approach.
2 The formula there if you broke this down 3 into a formula is the basic DOE five-factor f ormula on 4 the retention of radionuclides o r the source term for 5 the release from a reactor or non-reactor facility.
6 So, the bottom half of the figure is the 7 other two fundamental safety functions, the heat 8 generation and the heat removal. And it's basically 9 again just trying to represent that you can do that at 10 a high level just by the h eat generated f rom the d ecay 11 heat or from the core or f r o m whatever source that 12 you're addressing.
13 And then t he heat r emoval through the 14 vario u s p aths ultimately out t o the ultimate heat 15 sink. So, f or passive reactors it does generally look 16 something as s imple as this where it's just g oing from 17 the c o r e to the reactor c oolant s ystem or primary 18 system or whatever you want to c all the primary system 19 through a b uilding a n d then to a r eactor cavity 20 cooling system or something w here it's released to the 21 environment.
22 The failure on the bottom either in heat 23 generation or heat removal such that y o u have a 24 mismatch is in general what c auses the degradation of 25 the barriers in the top level approach. And so this NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 41 1 is how these things kind of generally fit together.
2 I know it's an over-simplification but it 3 was just a n a t tempt on our part to t ry to focus the 4 staff a s we developed what is t h e content in an 5 application a n d what the s taff's going to look at 6 during the review to focus on what's important.
7 You start with t he f undamental safety 8 functions as basically being a good p lace to start. 9 And then as w e build t hrough t his process as w e're 10 going to talk during t he day u sing various a nalytical 11 tools, probabilistic risk assessment, deterministic 12 assessments and other tools, you're basically looking 13 at how well does a design satisfy these fundam e n t al 14 safety functions.
15 MEMBER REMPE: If you only look at these 16 or what's in this diagram why would you need t o w orry 17 about having redundant shutdown systems because you 18 could have a low power reactor t hat stays critical for 19 a long period of time a s long as you can remove h eat. 20 So you've g o t ten rid o f t he general design criteria 21 needing to have redundant shutdown systems, right?
22 MR. RECKLEY: Well, as we go through the 23 process you would have t o s how t h a t whatever you're 24 relying on provides you the needed confidence.
25 And so if it is small enough an d s i mple NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 42 1 enough could one conceive that it be as you s aid, 2 perhaps. But you would h ave to have t h e c onfidence 3 th at that heat path for example c ouldn't be 4 interrupted, and if it c ould be interrupted then m aybe 5 you need either a diverse redundant and/or diverse 6 function in order to serve that function.
7 And that would come o ut o f all o f the 8 assessments we're going to talk about during the day.9 But if you g o d own t o could it be s mall 10 e nough or simple enough t hat you didn't n eed it, I 11 wouldn't r ule that out. B ut you'd have to s ee and the 12 point would have to b e proven that the r eliability and 13 the confidence t hat yo u h a ve i n t hat single t hing 14 would be enough.
15 So going back t o t he bow tie I tried to 16 represent in general t e rms what we're going to be 17 talking about today through licensing modernization.
18 And it captur e s b a sically this p art of the bow tie. 19 The internal plant events, malfunctions, failures of 20 plant equipment, external hazards, the plant systems 21 and op erational p rograms that are there to address 22 those events, and in t he beyond design basis category 23 if the technology has a p lant d a m a g e d s tate with an 24 unplanned movement of radioactive materials what the 25 plant might include to a ddress that p articular NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 43 1 scenario.2 It doesn't -- LMP doesn't feed over into 3 the external responses, t hings like siting and 4 emergency planning.
It doesn't d irectly address 5 environmental reports. And it doesn't directly 6 address security, radiological sabotage type events.
7 Although in all of those areas y ou can 8 draw some information from LMP.
9 So again looking at the LMP and h ow it 10 fits into the regulatory structure.
And this came out 11 of our June meeting so I w a n t e d t o touch on this a 12 little bit.
13 Within the l icensing modernization 14 activity t here are specific regulations that are 15 mentioned and credited for how this system -- this 16 methodology would work.
17 Examples of that are quality assurance in 18 the maintenance rule. A s you go through the 19 methodology it's going t o define the desired 20 reliability of equipment, for example. How d o you 21 e n s u re once you go from t he design s tage into 22 operations that that reliability i s maintained.
23 Y o u'll u se something like the m aintenance rule o r 24 something related to the maintenance rule in order to 25 help provide that confidence.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 44 1 As I mentioned the LMP interfaces although 2 it's not specifically m e ntioned in the document or 3 addressed specifically it is an interface with other 4 regulatory requirements l ike siting, emergency 5 planning and environmental reviews.
6 As I mentioned under e mergency planning 7 when you say for non-light water reactors how will you 8 define the event by which you'll judge whether you're 9 remaining under one rem to activate the P A G s , the 10 protective action g u ideli n e s , that will c ome out of 11 the events that are identified through the LMP.
12 There are requirements that are beyond LMP 13 in which t he LMP doesn't directly i nterface but w hich 14 an a pplicant would have to address. Some of those are 15 just routine effluents, Part 20.
16 If we do an equivalent to Appendix I for 17 non-light water reactors Appendix I and 10 CFR Part 50 18 which address those routine e ffluents.
Worker 19 protections and other Part 20 kind of requirements.
20 As I mentioned security and aircraft 21 impact a ssessments not directly affected.
But 22 designers should be looking at these requirements as 23 they're l ooking a t LMP t o see that the overall design 24 is m e e t ing all of these r equirements and from t heir 25 perspective that they meet i t i n the most efficient NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 45 1 way they can.
2 One easy probably example is aircraft 3 impact. I f t h ey do LMP and look at all the natural 4 events like perhaps wind is an e asy example a nd decide 5 that a building structure has to b e X and they 6 continue along on that a ssumpti o n a ll the way u ntil 7 they g e t further in the design and then t hey'll say 8 now we're going to do our aircraft impact assessment 9 then they face the potential to s ay oh, t hat building 10 should have been thicker , o r some c ombinations of 11 walls should have been different, or maybe we should 12 have given more thought to putting it below grade.
13 So they need to be aware of all of these 14 things as they're doing the d esign a nd I think this is 15 the case. We all experience that they're well aware 16 that they need to address all of these t hings. But I 17 did want to j ust separate out. LMP doesn't a n swer 18 every question, it d oesn't answer every regulation, 19 that there are others out there that they'll have to 20 address.21 MEMBER SKILLMAN:
Hey B ill, before you 22 change that slide. This i s Dick Skillman.
This list 23 appears to m e to be a list t hat was constructed or 24 developed by designers.
25 And let me make a contrast.
Over the last NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 46 1 couple of decades we've watched the regulations 2 change. Give you an example. In 1971-72 Appendix B 3 to 10 CFR Part 50. Later on I t hink t he gold standard 4 was 50.65 the maintenance rule. I mean t hat was a 5 fundamental change.
6 Industry resisted that like the dickens 7 and it has turned out t o b e o ne of the most important 8 ch a n g e s in regulation at least from my years of 9 experience.
10 But there have been other lessons learned 11 t h a t may not be represented here that come f rom t h e 12 operating teams. As I said this appears to be a list 13 developed basically by designers.
14 I'm wondering are there some key lessons 15 learned from the operating side of industry and from 16 the o versight of operations by the NRC t hat would add 17 to this.18 Actually, make it better.
19 MR. RECKLEY: I would assume t h a t t here 20 are.21 MEMBER SKILLMAN: I think so too.
22 MR. RECKLEY: Let m e cla rify that this 23 wasn't intended to be all-inclusive.
24 MEMBER SKILLMAN:
T his is not a 25 comprehensive list.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 47 1 MR. RECKLEY: Yes. A nd it wasn't by 2 designers, it was just by me.
3 But the primary reason I wanted to address 4 it was to say that L MP doesn't answer every question.5 MEMBER SKILLMAN:
It's a good place to 6 start. What I'm suggesting is that t here is a I d on't 7 want to say list. There is a recognition by the 8 operating individuals t hat yes, you have to design it 9 properly, yes, you have to i nclude design features and 10 functional performance requirements to ensure that the 11 machine does w hat it's supposed to and that the health 12 and safety of the public are protected.
13 But beyond the i f you will design features 14 there are probably some other issues that need to be 15 woven into quote "other requirements" to pr o t e ct or 16 further enhance the l e v el of s afety of new plants 17 whether they're light water p lants or th e y are non-18 light water plants.
19 MR. RECKLEY: I agree with you.
20 MEMBER SKILLMAN: Thank you.
21 MR. RECKLEY: And perhaps when we get into 22 the defense-in-depth discussions and the i ntegrated 23 decision-making panel they c an touch o n that a little 24 bit later this morning or this afternoon.
25 MEMBER REMPE: So, I actually am glad to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 48 1 hear you s ay this and I noticed in the d ifference 2 between whatever version we're l ookin g a t , N versus 3 the ones we looked at last summer, they actually a dded 4 a paragraph explicitly s aying hey, j u st because you 5 meet the top level regulatory cr i t eria that we 6 identified doesn't m ean you're g o i ng to satisfy all 7 the regulations.
8 That was a concern I had when I read the 9 version last summer. So I'm glad to see both of you 10 guys emphasizing that now.
11 MR. RECKLEY: We t h a nk you. T hat was 12 directly in response to the question.
13 CHAIRMAN BLEY: This is Dennis Bley. I'm 14 going to follow up on Dic k's c omment and your 15 response.16 One place where w e've really seen the kind 17 of things Dick's talking about i s on new l y designed 18 plants. The main control room board and operating 19 procedures linked together through I'll say software 20 but are linked together prov ide the operators with 21 additional tools to understand things about t heir 22 plant, or to a large extent based on events that have 23 happened in the past. It kind of f its in that 24 category.25 MR. RECKLEY: Y es. Again, agreed. One of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 49 1 the things that we do h ave to keep in mind I t hink is 2 I don't w ant to overstate this too much, but a t l east 3 the operating fleet is o perating largely i n a nineteen 4 seventies world.
5 And so as we go through things lik e t he 6 man-machine interface that y ou're mentioning, Dr.7 Bley , t he t echnology has developed a lot over t hose 8 decades and I think it's --
9 PARTICIPAN T: I'm just joking. I w ould 10 never suggest such a thing.
11 ACTING CHAIRMAN CORRADINI:
I think we 12 have people online that have to mute.
13 MR. RECKLEY: That generated a response 14 anyway. So I think i t's fair to say that people 15 designing plants today a re looking at t he a v a i l able 16 technology and areas like man-machine i nterface and so 17 forth. 18 So going forward and getting a gain to try 19 to lay out a little bit of the high l evel a nd then the 20 industry folks are going to talk to you for a couple 21 of h ours about the details. And t hey're also going to 22 go through largely at the suggestion from the June 23 meeting some experience that has been gained through 24 tabletops with different designs.
25 ACTING CHAIRMAN CORRADINI:
Did we already NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 50 1 do s l i des 13 and 14 and I just m issed it? Just 2 checking.3 MR. RECKLEY: I'm a l ittle repetitious.
4 So you wouldn't have missed anything anyway.
5 The general approach within t he r egulatory 6 guide and also the companion SECY paper building off 7 of NEI 18-04 is to divide t he framework into licensing 8 basis events, and that gets looked a t b oth from a 9 probabilistic risk assessment viewpoint as well as 10 deterministic viewpoint.
11 The safety classification and performance 12 criteria, how do y ou d e f i n e t hose for structure 13 systems and components.
Looking at w hat function does 14 that SSC play, which ones would be i dentified as b eing 15 safety-related a nd therefore subject to the higher hat 16 in terms of quality assurance.
17 I think probably more importantly to some 18 degree is how d o you look a t t he non-safety-related 19 equipment a nd determine what s pecial treatment 20 requirements, what are the reliability and 21 capabilities you're crediting for that equipment and 22 how do you assure it once you get into operations.
23 We h a v e t hat now to some degree through 24 things like regulatory t reatment of n on-safety 25 systems, RTNSS. And if you go over to 50.69 y ou have NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 51 1 it.2 But this is a g a i n not a n overlay in how 3 can you change a design, or how can you c hange your 4 operations for a reactor t hat's already been designed, 5 but from t he beg i n n i n g how c an you build in this 6 logic.7 Going back to the firs t d iscussion.
In 8 personal opinion, one of the better things about this 9 overall approach again in my view is the marrying of 10 the design and operations better than we traditionally 11 did under Part 50. And there will be a talk l ater on 12 about looking at the p lant capability or t he hardware 13 and the companion performance and operational programs 14 that go along with that.
15 And that is included also in the defense-16 in-depth assessment which is the last bullet up here 17 looking a gain at t he p rogrammatic a r e a s , at the 18 hardware and t h e n giving it a good scrub through an 19 integrated decision-making process looking at it 20 through multi-disciplinary going to D ick's point, the 21 operat i o ns as well as design to see how it carries 22 forward.23 MEMBER REMPE: Before you leave that 24 slide. The one thing when I read through this and I 25 think about i t, this integrated decision panel process NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 52 1 which they do have additional guidance on in NEI 00-2 04. 3 Has the staff ever interacted with s uch a 4 panel? Especially the way they've p laced such 5 emphasis on this p a n e l it's going to be with the 6 design f rom its inception through licensing.
I'm just 7 wond e r i n g what kind of issues might crop up with it 8 versus h o w t h e regulator a nd t he panel cite t heir 9 opinions.
10 MR. RECKLEY: We've --
11 MEMBER REMPE: -- it will work.
12 MR. RECKLEY: We've had closely related 13 experience I would say t hrough both 5 0.69 type reviews 14 and our reviews of PRAs and the peer review process.
15 But maybe I'l l j ust ask the IOU f or the 16 industry p resent e r s i f t hey have any other examples 17 where the staff has interacted.
18 I think t here's been a couple of c lose but 19 not e xactly from the point of the design where we are 20 now going forward on these non-light waters.
21 MEMBER REMPE: So i n past experiences with 22 50.69 how did it work? Was it well documented? Did 23 you like how this multi-experience whatever b ackground 24 panel came up and supported the design?
25 MR. RECKLEY: I might h ave to take an IOU NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 53 1 on that unless Jason?
2 MR. REDD: Good morning, Jason Redd from 3 Southern Nuclear.
4 I believe that we can make some comments 5 on this -- make some c omments on this topic in our 6 session coming up soon. Thank you.
7 MEMBER REMPE: Thanks.
8 MR. RECKLEY: That w ould at least b e from 9 the industry side. I'll take a n I OU maybe during 10 lunch to see if I can get w ith NRR. I haven't been 11 personally involved so I can't.
12 MEMBER REMPE: Even with the tabletops I 13 don't think that you've had that interaction yet with 14 the LMP process at a l l. So I'm real c urious on how 15 it's going to work.
16 MR. REC K L E Y: So, one o f the -- another 17 area is t he key considerations as the staff looked at 18 this and developed the draft guide and the SECY paper, 19 the e nclosure 1 to the SECY paper and we mention it in 20 passing i n the draft g uide goes through the evolution 21 of this approach.
22 You can take it probably back f urther than 23 this if you want but I tend to s tart with the 24 development of the Advanced Reactor Policy S tatement.
25 There w as an immediate t est o f t he Advanced Reactor NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 54 1 Policy S tatement through interactions funded by DOE 2 and the staff l o o ked at various designs including 3 PRISM, modular high-temperature gas reactor and PIUS 4 at the time as well as the CANDU 3.
5 Lessons l earned from that in the 6 identification issues was in SECY 93-092.
7 Around this same time the risk-informed 8 performance-based focus with the PRA p olicy s tatement, 9 the 1 999 Commission w hite paper o n risk-informed 10 performance-based regulation was issued.
11 That obviously related t o the things that 12 were going o n at the same t ime. T hose efforts were 13 applicable to both light water operating reactors as 14 well as the development of t he n on-light water reactor 15 technologies.
16 SECY-0347 was a follow-up where we came 17 back to the Commission to propose resolution of some 18 of those policy issues. That ends up being a key 19 paper a nd I'll talk a b out i t a little more this 20 afternoon.
21 Just as an example of the marrying o f the 22 risk-informed approaches and the development of non-23 lights a s well as o ther reactors you had the 24 development and issuance of NUR E G-1 860 which is a 25 feasibility study for a risk-informed approach.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 55 1 Throughout all of t h a t you can s ee that 2 some similarity to the traditional light water reactor 3 l icensing structure is m aintained, but one o f t h e 4 things as we go through today and as you look at the 5 draft guide a n d the C ommission paper i s there are 6 differences and s ome of those differences are h ard to 7 recognize on first blush because the terminology 8 that's used uses some of the same terms b ut with a 9 different definition.
10 And so just be a l ittle c areful a s you go 11 forward to say oh, I know how design basis events are 12 analyzed. Design basis events are defined for light 13 water reactors, they're d efined for non-light w ater 14 reactors u s ing this methodology.
It's a different 15 definition.
16 Safety-related.
The derivation of how 17 something i s safety-related i s slightly different here 18 than it is in Part 50, Part 1000 for light w ater 19 reactors.20 A n t i c i p a t ed operationa l o c c u r r e n c e s. S a m e 21 term, slightly -- and similar but slightly different 22 definition i n this case v ersus what you may be 23 accustomed t o in chapter 15 of the light w ater 24 reactor. 25 So i t's just a caution that whe r e a s the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 56 1 overall structure is similar t here are key differences 2 and some of those differences are hard to pick up on 3 in p art because the s ame t erms a re used with different 4 definitions.
5 ACTING CHAIRMAN CORRADINI:
So you'll 6 remind us of this since we're forgetful.
7 MR. RECKLEY: One o f the reasons to b ring 8 it up now is so when you bri n g u p a q uestion the 9 answer might be careful, this is one of the a reas 10 where our d efinition is different than the Part 50 11 definition.
12 ACTING CHAIRMAN CORRADINI:
So let me ask 13 you, maybe you said it, I didn't hear you mention the 14 next generation, the NGNP.
15 So I guess I'm empirical enough that I 16 want an example. So what is it about what we're g oing 17 to hear that's different than what was p r o p osed for 18 the NGNP?19 MR. RECKLEY: It is most similar to NGNP 20 and I should have listed it up t here. It's on future 21 slides. It is most similar to the approach of NGNP.
22 It's been r e f i ned a little bit b ased on 23 interactions both with t he staff and also as the 24 effort w as made to ensure i t wo u l d be technology-25 inclusive it was tweaked some.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 57 1 But it closely resembles NGNP. I see Karl 2 Fleming, so Karl, if you want to weigh in.
3 MR. FLEMING: Karl Fleming, LMP project.
4 During my p resentation t his mornin g a nd maybe e arly 5 this afternoon I will highlight the similarities and 6 differences with NGNP.
7 But Bill is c orrect, it's primarily the 8 NGNP process with some refinements.
9 ACTING CHAIRMAN CORRADINI:
S o, if y ou can 10 hold on a second. Then y o u'l l tell us more, but at 11 this point I personally fo u nd reading t hrough this 12 stuff d ifficult.
Mayb e i t was b ecause i t's process 13 and framework.
14 I really think i f i t's t hat similar an 15 e m p i r ical example w ould really help. Maybe the 16 industry gets it, but at lea s t m e trying to wade 17 through the documents, I kept on asking m y s elf gee, 18 how is this different.
19 Because the frequency consequence curve is 20 1860, the N G N P frequency consequence curve w as 1860 21 with attempts to place DBEs and LBEs on it.
22 So I think it w ould help for the less than 23 completely involved individuals in t his to marry t hose 24 because I just think that would be a nice way of 25 walking through this.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 58 1 I really had a hard t ime in some s ense 2 trying to u nderstand the process step s w hich you're 3 going to go through.
4 MR. FLEMING: Good feedback.
5 MEMBER SKILLMAN:
I'd like to weigh in on 6 that just for a second. It seems o ut i n the operating 7 plan t w orld we use a term called error likely 8 situations.
This is one. But i t's right here in the 9 staff.10 And it just seems that it might be useful 11 if we're u sing the s ame acronym at least mark the 12 uniq u e use of the acronym with a sign or something 13 that communicates this is f or the different 14 application so that those who would read would say ah, 15 get it, this is not identical, it's similar, caution.16 But this really is an error likely 17 sit u a t ion for those who are trying to digest this 18 information. Thank you.
19 MEMBER BALLINGER:
Might we a s k f or a 20 table that clearly lists the differences?
21 MR. RECKLEY: You can ask.
22 MEMBER BALLINGER:
Can we make it a formal 23 request? 24 MS. C UBBAGE: In the back of the NEI 1 8-04 25 document there is a table that lists a number of t erms NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 59 1 and in the right column if it says LMP that means it's 2 a definition t hat came from LMP, and i f it's t he same 3 definition as elsewhere it says where it came from.
4 MEMB E R BALLINGER:
I read that but I 5 wasn't sure whether it was complete.
6 MR. RECKLEY: We will take a look and by 7 the full committee we will prepare -- we'll p repare as 8 best we can.
9 I just want t o make s ure, your request was 10 on terminology or a comparison with NGNP?
11 MEMBER BALLINGER: Terminology.
12 MR. RECKLEY: Okay. Te r m i n ology is a 13 little easier.
14 And as Amy pointed o u t one of the m ajor 15 things that was developed as we w ent through t his was 16 the glossary that's at the back of 18-04.
17 So again, keeping at kin d of the h igh-18 level discussion as I m entioned the methodology 19 consists of the three primary elements, the licensing 20 basis event selection and analysis, the classification 21 of equipment and the derivation o f performance 22 requirements in assessing defense-in-depth.
23 I'll say it probably a f ew times g oing 24 through the day but the emphasis here is that this is 25 an integrated approach and the staff is looking at NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 60 1 these three elements within this methodology and they 2 are like three legs to a stool. T hey're all 3 complementary and they're all interdependent.
4 And so when we say that this is an 5 approac h t hat's okay for the selection of licensing 6 basis events that goes to that's okay because of the 7 way the defense-in-depth is also addressed within this 8 methodology.
9 Likewise the safety classification and the 10 assessment of the d efense-in-depth.
T hese things 11 i n terplay w ith each other and we're saying that t h e 12 three elements fit in this process and work together.13 You would be challenged j u s t to pick up 14 one of these elements and s ay I'm going t o pick my 15 licensing basis events this way but I'm not going to 16 do safety classification or a defense-in-depth 17 assessment in the same way.
18 Then the next bullet o n the slide. 19 Another thing to keep in mind is when it comes to the 20 actual regulatory decisions t he criteria are basically 21 the sa m e in this methodology as are in the current 22 rules.23 The 5 0.34 25 rem number, that's used in 24 this methodology.
The safety goal, the NRC safety 25 goal at the l ower end of t he curve, that's also within NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 61 1 this methodology a s one of t he a g g r egate measures 2 that's ultimately used t o show the adequacy of a 3 design.4 The assessments are performed both using 5 risk-informed and deterministic approaches and as was 6 mentioned that includes the engineering judgment that 7 would come from the integrated d ecision-making 8 process.9 And the methodology includes a specific 10 element and step for looking at defense-in-depth and 11 how t hat's provided u sing b oth hardware and 12 programmatic controls, and how the programmatic 13 controls are developed t o support the defense-in-depth 14 assessments, the uncertainties that might exist in a 15 particular design and so forth.
16 And for me that becomes a very important 17 point to keep in mind as you go forward because one of 18 the q uestions t h at often arises for non-light w ater 19 reactors i s how do you address the availability of 20 less operating data, of less operating experience.
21 And one key way that that's d o n e is 22 through this defense-in-depth assessment and really 23 looking at b oth the plant capabilities or the hardware 24 and what wo u ld be appropriate in terms of 25 surveillances and monitoring and reliability targets NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 62 1 and all the other things t hat you can set on the 2 operating side in order t o try to address some of 3 those uncertainties.
4 MEMBER R E MPE: So on t he second bullet in 5 your discussions with industry this does -- e specially 6 for -- well, design certification you have to assume 7 some sort of characteristics about the site.
8 In the past, in the MHTG R e xample they 9 r eference that EPRI document that had l ike s o m e 10 hypothetical site that b o u n d ed 85 percent or some 11 fraction of the site.
12 Did you try and push -- I mean, you're 13 going to have a lot of different v endors c oming in 14 theoretically with a bunch of different designs. And 15 if t hey w ould all just pick the same theoretical site 16 wouldn't that make t h i n gs easier and d id y ou guys 17 discuss that with NEI?
18 MR. RECKLEY: It might make it easier in 19 some regards f or us. The problem that arises is that 20 these technologies t o some degree have different 21 potential uses, customers and locations that makes it 22 kind o f hard to say we're going t o pick a generic 23 envelope if you will.
24 Whereas some designs might be able t o say 25 off t he b at we don't see Alaska a s a potential siting NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 63 1 others are being developed specifically for those kind 2 of environments.
3 And so we are basically comfortable 4 leaving it u p to the d esigners to say you k now the 5 marketplace that you're trying t o pursue. When it 6 comes to picking an external envelope to try t o b ound 7 where you want to put these it's really up to you to 8 do.9 MEMBER SKILLMAN:
E xcuse me, Dennis, this 10 is Dick. Go ahead.
11 CHAIRMAN BLEY: O k a y. Bill, you said 12 something earlier that got me c urious. You w ere g oing 13 into the (telephonic interference)
NEI 18-04 and 14 something we put together.
15 In the guidance that you're going to get 16 to t his afternoon, it looks a s if NRC plans to endorse 17 NEI 18-04 with a few exceptions or c larifica tions. 18 How -- w hen you look at N EI 18-04 is that k ind of a 19 consensus between the industry -- the NRC, or is it a 20 separate product that you're evaluating later -- new 21 reg guide?
22 MR. RECKLEY: It's a separate document, 23 NEI 18-04 that the i ndustry owns. And they'll be 24 asking for our endorsement via the regulatory guide.
25 At the same t ime they didn't d evelop it in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 64 1 a vacuum and we've gone t hrough -- you'll notice it's 2 revision N. I think w e've seen a t t he staff l evel 3 during interactions three or four of t hose i terations 4 and provided feedback of our own as well as what the 5 industry has provided.
6 And as Amy just mentioned plus the white 7 papers t hat preceded it, plus NGNP that p receded t hat. 8 And so it's their product and they're free to put in 9 what they want. A t t he same time we've provided 10 feedback in order to if possible minimize the number 11 of exceptions or even clar i fications that we m ight 12 need to add.
13 MS. CUBBAGE: And Dennis, thi s i s Amy 14 Cubbage. I f you're specifically g etting at the 15 glossary i n the back w e specifically discus s e d that 16 with industry at m u ltiple p ublic engagements and we 17 provided input to them on that.
18 CHAIRMAN B LEY: Thanks. I was just trying 19 to generalize.
20 MR. RECKLEY: And by the way, that's not 21 any different than other guidance documents that are 22 developed by the industry and then ultimately endorsed 23 by the NRC.
24 M E MBER SKILLMAN:
I'm going to hold u p , 25 thanks.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 65 1 MR. RECKLEY: And a gain I'm going to just 2 t o u ch o n these because there w ill b e additio n a l 3 discussions of the actual methodology.
4 I j u s t wanted to put a little s taff 5 context and maybe overview to prepare for the 6 subsequent presentations by t he developers of NEI 18-7 04.8 A key aspect of this methodology as well 9 as the NGNP and A N S 5 3.1 and basically the w hole 10 methodology that largely a r i s es from the gas cooled 11 reactor community and i s b e ing revised and updated 12 here was the use of the frequency consequence diagram.13 And one of the things that we would like 14 to emphasize h ere is what's in the bullet which is an 15 extract r ight from NEI 18-04 and it's an extract more 16 or less right from the reg guide is that the target 17 figure is a useful tool when you'r e d oing the 18 discussions assessment, when you're doing the safety 19 system classifications, b ut don't look at it as an 20 acceptance criteria where on one side o f that line 21 you're okay and on the other side of the line you're 22 not okay.23 The other caution --
24 A C TING CHAIRMAN CORRADINI:
So can I --25 with your first caution. But as we at least I thought NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 66 1 we s aid in June if I start approaching the line things 2 become concerning.
T hat's the p oint o f having some 3 line.4 MR. RECKLEY: That's right.
5 ACTING CHAIRMAN CORRADINI: Okay.
6 MR. RECKLEY: Yes, the closer you are to 7 the l ine the m ore concern. And t here is a point w here 8 it's unacceptable but we're trying not to use this 9 curve that way.
10 As I mentioned e arlier ultimately the 11 regulatory decisions are made u sing basically the same 12 metrics w e use now which are the aggregate measure of 13 the NRC safety goal p olicy state ment, t he specific 14 assessments that are done against the criteria in 10 15 CFR 50.34, the dose r eference values, the 25 rem 16 number.17 For those designs or projects that are 18 pursuing a reduction in the emergency planning zone, 19 that EPA PAG dose limit is marked on the figure. That 20 might become a reference v alue that they n eed to 21 address in the design.
22 But overa l l t he figure is used in the 23 context of identifying risk-significant licensing 24 basis events. It is u sed in th e d e fense-in-depth 25 assessment and in the safety classification.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 67 1 It's I think familiar to y ou, the 2 anticipated operational occurrences, the D BEs. A gain 3 this is o ne of those cases w here there's a d efinition 4 difference.
5 DBEs are those event sequences between 10-6 2 an d 10-4. In light water reactors a DBE, that 7 terminology is used as a broad category that is used 8 within the definition of safety-related equipment and 9 includes design basis external events, anticipated 10 operational occurrences and design basis accidents or 11 postulated accidents.
I forget the exact terminology 12 but they're the same thing. And special events.
13 And then to me what i s actually k ey to 14 this methodology is the inclusion of the beyond design 15 basis events from the beginning a nd the assessment of 16 those low likelihood events within the methodology.
17 I'll let it go into this afternoon for a little more 18 discussion o f t h at, but again you can contrast that 19 with the existing framework which through b eing 20 conservative in t he assessment of postulated accidents 21 and anticipated operational occurrences was largely 22 trying t o a ddress the fact that they didn't address 23 some lower likelihood beyond design basis -- what we 24 now call a beyond design basis event.
25 The last category on the curve t h e re is NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 68 1 that DBAs, design basis accidents, are maintained as 2 a c ategory w ithin the licensing b asis events. They're 3 done largely the same as is used n ow within chapter 15 4 of a typical safety analysis report crediting safety-5 related equipment and using analytical methods that 6 are consistent with t he guidanc e t h at the staff has 7 issued for chapter 15 transient and accident analyses.8 MEMBER REMPE: So a few weeks ago I was at 9 a meeting and a designer p ut up a plot that showed the 10 risk o f the plant as a function o f years based on 11 their increased k nowledge.
And I w ould have actually 12 liked to have seen a similar plot that also had the 13 risk of t heir plant as a function o f dollars invested 14 in t he design development because it was going up and 15 down.16 The reason I'm b ringing t hat up now is 17 tha t i t might be good to provide some perspective 18 about what was it Rickover's letter that said a p aper 19 reactor is very, very safe and then as you have more 20 knowledge and more information t hat you find out that 21 it has more issues that you have to address.
22 I just think that some perspective might 23 be useful in your document of what the staff expects 24 or some c aveats to the design d e v e lopers t hat are 25 coming out with th eir concepts claiming they're so NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 69 1 safe.2 MR. RECKLEY: W e try to d o t hat through 3 the pre-application discussions t hat we have with them 4 as does EPRI and others that are involved in various 5 exercises. So we try.
6 MEMBER MARCH-LEUBA:
Okay, this figure, I 7 don't want to call i t -- i s m erely a mathematical 8 problem. I g uess the l eft side of my brain. And the 9 issue is I may not be using t he proper methodology, is 10 segmentation of events.
11 I f I take LOCAs a nd I decide t o call i t 12 LOCAs that happen at midnight, LOCAs a t 1 a.m., L OCAs 13 at 2 a.m. suddenly the frequency of my LOCAs is 24 14 times more.
15 So w h e n you plot only -- b y making my 16 events very, very specific I get a lot more events and 17 I don't c hange the line. See what I'm talking about? 18 There has to be some guidance.
19 ACTING CHAIRMAN CORRADINI: I think what 20 Jose is asking is what Dennis asked in June which is 21 the bundling of these so they're appropriately bundled 22 so that I don't by parsing e nough they all get --23 well, that's what I think you said.
24 M R. RECKLEY: This is a question t hat's 25 come up. I guess I'll a sk Dr. Fleming if h e wants to.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 70 1 MR. FLEMING: It's a v ery g ood comment. 2 The L BE in t his process is defined by constructing 3 event sequence families.
And i t requires you to g roup 4 together event sequences t hat have similar i nitiating 5 event challenge to the plant safety functions and if 6 there is a release mechanistic source term.
7 So you're required to group the sequences 8 that are similar to avoid abuses like subdividing like 9 that.10 MEMBER MARCH-LEUBA: That has to be very 11 specific in the guidance and should be on the standard 12 review plan. That should be part of the review that 13 they didn't cheat on the generation.
14 And also at the end of the day if I have 15 a house that is downwind from t his rea c t or I d on't 16 care what my risk is due t o a LOCA I want an internal 17 risk. And I don't k n o w how you add up all t hese 18 points to give me my risk i n my house f ive m iles 19 downstream.
This w i l l give you a risk for each 20 particular e vent. Again I want to know w hat is my 21 risk.22 MR. RECKL E Y: Right. And there are 23 aggregate me asures where you take the w hole risks. 24 The summation of the sequences.
25 MEMBER MARCH-LEUBA:
B ut you probably will NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 71 1 have eliminated a whole b unch of events to do the 2 aggregate. You will only aggregate the DBEs.
3 MR. RECKLEY: And the beyond design b asis 4 events.5 MEMBER MARCH-LEUBA:
You will aggregate 6 everything?
7 MR. RECKLEY: Yes.
8 MR. FLEMING: Yes, if I might amplify. 9 Because one of the applications i s to select licensing 10 events for different applications including coming up 11 w i t h our design basis accidents we needed a tool t o 12 look at t he risk s ignificanc e of individual LBEs 13 separately.
14 However, we also have three c umulative 15 risk metrics where we accumulate the risk from all the 16 event sequences agai n s t the two QHOs f rom the NRC 17 safety goals. And w e also h ave a m etric for the h igh-18 frequency low c onsequence events that's based on 19 assuring that 10 CFR 20 is maintained.
20 So we have t he aggregate measures and the 21 separate measures.
22 MEMB E R KIRCHNER:
Well, let me ask a 23 specific question.
Which individual ris k is the 24 anchoring point down at the bottom right of the -- is 25 this 750 rems which is the large release, or is this NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 72 1 early fatality within one mile?
2 MR. RECKLEY: And this is the caution that 3 we bring out both in the reg guide and elsewhere is 4 one of the reasons again tha t t his methodology we 5 think works within the overall construct is that the 6 bottom figures actually don't c orrelate to actual 7 criteria.8 For example, the bottom that you'll see is 9 the effective dose over a month whereas the criteria 10 for emergency planning will use a d ifferent number, a 11 different time period.
12 The 750 r em r oughly correlates maybe to 13 the prompt fatality but we didn't want to argue --
14 MEMBER KIRCHNER:
That's much g reater than 15 a prompt fatality.
16 MR. RECKLEY: But we didn't want to --
17 MEMBER KIRCHNER:
It's not roughly 18 correlating. LE50 is a much lower number.
19 MR. RECKLEY: Yes, i t's a c o u p l e of 20 hundred. So we knew that as we went in and for the 21 purpos e s of t he methodology.
A gain, this is why I 22 keep coming back. As an i ntegrated process to look at 23 the methodology we're fine that that number does not 24 actually correlate to t he 50.50 prompt fatality 25 number.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 73 1 MEMBER KIRCHNER:
Because y ou c an't 2 reconcile all those it is cleaner t o s how it a s f ixed 3 po i n t s a n d a solid line. But like in 10 C FR 5 0.34 4 there is that footnote t hat cautions people that w e're 5 not intending
-- let's see, it's there, t he 50.34 dose 6 limit.7 The intention is not to approach that 25 8 rem exposure. So I just would feel personally, this 9 is just one opinion, if there were some band on this 10 that suggested you don't want to be approaching this 11 line from what would be on the left side of d ecreasing 12 risk significance.
Yo u d o n't want to b e bumping up 13 against this line with your quote unquote "adv a n c ed 14 design." 15 The expectation is that you're not going 16 to really come close to this or it's not an advanced 17 design. By policy statement of the Commission.
18 So, the expectations a re not to press that 19 envelope.
A nd I don't know visually how best to do 20 that other than putting some kind of hatched area on 21 the lower side of that that kind of suggests. And I 22 know, I guess the designers will go and s ay oh, I see 23 what they mean, it's now not 25 rem, it's 20.
24 But something that s uggests that you're 25 not expecting these designs to push this envelope.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 74 1 MR. RECKLEY: Right. The presentations on 2 18-04 will specifically address one there is a hashed 3 area that's t wo orders of magnitude l ower than this 4 line for looking at what you'd c all a risk-significant 5 event.6 Then as I mentioned earlier m ost of t hese 7 designs are going to go for the one rem at the fence 8 objective. That would limit it as well.
9 But I think we'll get into it and if it's 10 not addressed then I'll be back this afternoon. But 11 i t's a good comment. Yes. A nd we tried to addre s s 12 that specifically within t he regulatory guide by 13 saying don't look at these points as the accep t a n ce 14 criteria.15 Dr. Corradini mentioned 1 860 earlier. 16 I'll offer a personal opinion. It was a g reat 17 document but t he stair s tep approach, many of u s like 18 the straight l i n e s and that causes you to have some 19 compromises here or t h e r e versus h aving so many 20 different break points as 1860 had.
21 So, but I u nderstand your point a nd as we 22 get into it i f it's not a ddressed as we go through it 23 we can talk. That would be something we could tweak 24 in the reg guide.
25 So I'm g oing to just quickly go t h r ough NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 75 1 the last couple of slides because again all of this is 2 going to get repeated.
3 So the safety classification.
This s lide 4 just has the definitions which we'll get to as we go 5 through.6 MEMBER MARCH-LEUBA:
I have questions and 7 mayb e I n eed to ask this afternoon.
F irst is 8 language.
I don't u nderstand what y ou say on the 9 first bullet. If I'm r eading this correctly the 10 designer selects which SSCs are safety-related o r not. 11 And he decides to -- t hose SSCs t hat are needed to 12 meet the classificati o n o f DBEs must b e safety-13 related. Correct?
15 MEMBER M ARCH-LEUBA:
D BEs. The f irst 16 couple of sentences, to mitigate the consequences of 17 DBEs --18 MR. RECKLEY: Within the curve. Yes.
19 MEMBER MARCH-LEUBA: And then it says to 20 mitigate o n l y t hose DBAs which -- that only rely on 21 SRs. There are other DBAs that ca n r e ly on long --22 I'm talking about language.
23 MR. RECKLEY: Okay. If t here's a 24 confusion we can take that as a comment b ut the intent 25 is t hat DBAs just much l ike they d o now assume safety-NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 76 1 related equipment.
2 MEMBER MARCH-LEUBA:
All DBAs m ust have 3 safety. That's not what that sentence says.
4 Now, the most i mportant comment is the 5 second bullet which I think you are trying to address 6 my concern. I detect a circular logic here. Let me 7 give you a simple example.
8 I have a very strong con tainment and I 9 have an accident that melts the core but nothing c omes 10 out of c ontainment.
Therefore the frequency 11 consequence is very small, i t's way to the left to 12 your line and it's not a safety -- a risk-significant 13 event. Correct?
14 So then I decide that because it's not a 15 risk-significant event I don't need a containment 16 because I don't need to have it safety grade. This is 17 circular logic there.
18 MR. RECKLEY: It's a ctually what's trying 19 t o be addressed here is t hat i f you have something 20 yo u'v e placed in the beyond design basis e vent 21 catego r y as a result of a low frequency and you're 22 relying o n a par t i c ular barrier to limit the 23 consequence of that e vent that that i s r eason t o make 24 it s afety-related because if yo u t o o k away that 25 barrier you would move up.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 77 1 MEMBER MARCH-LEUBA:
It will move up. So 2 what are we gaining --
3 MR. RECKLEY: I might have explained that 4 wrong. 5 MEMBER MARCH-LEUBA:
N o, no, you d i d it 6 perfectly.
What do you gain by d oing it that way? 7 You should have -- m ake that event a design b asis 8 event that you have to analyze and make the SSCs that 9 you r ely on safety grade. Where are you baking it, I 10 don't understand.
11 ACTING CHAIRMAN CORRADINI:
I think w e can 12 come back to this one. Karl can come b ack to it. You 13 can take it up with Karl.
14 MEMBER MARCH-LEUBA: Okay.
15 MR. RECKLEY: So just the last two. I've 16 addressed this largely, the defense-in-depth 17 assessment and this is going to be talked about by the 18 industry in the context of NEI 1 8-04. A gain stressing 19 that it includes PRA, deterministic assessments, it 20 includes hardware and programmatic controls. And so 21 in our view it's a good tool to apply to a design to 22 make sure that you're addressing the u ncertainties and 23 other objectives that we have in this process.
24 T h en lastly I did want to touch on th a t 25 the reg guide that we're pre p a r i n g is o n content of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 78 1 applications.
That is the rule that this reg guide is 2 being used fo r. So we felt it necessary t o add a 3 little discussion, more than what's in 18-04 as to how 4 this guidance is used i n the development of the s cope 5 and level of detail of information that we expect to 6 be in applications.
7 And so I'll get into this this afternoon 8 in a little more detail, b ut p rimarily if you look at 9 t h e fuel, t he primary systems and the other primary 10 barriers if you go b ack to for example that f irst 11 principle slide what is retaining your radionuclides 12 those kind of barrier s w o uld l argely need to be 13 described much as they a re now because that's w h e re 14 you're going to get how do you get a release. You get 15 a release because you're failing the f u e l , you're 16 failing the matrix, you're failing a primary system.
17 So that kind o f information would largely 18 be similar.
19 But then as it relates to other systems, 20 ancillary systems we want to focus o n w hat is the role 21 of those systems in supporting again t hose fundamental 22 safety functions.
And from the beginning we know that 23 many of t hese designs a re going to rely less o n t hose 24 anci l l a ry s ystems, things like a c p ower and t o some 25 degree forced cooling water or other active systems.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 79 1 And so t his process w e w ould hope w ould 2 build into the beginning that this is how you decide 3 how much information you n eed t o provide on t hose kind 4 of systems.
5 Likewise whenever you're r elying on 6 programmatic controls that need s t o be addressed in 7 the a pplication so that you're looking at the same 8 time in c oncert to hardware a nd the programmatic 9 controls to provide the needed assurance.
10 I th i n k with that then I'll just set up 11 that t he n ext presentations will be 18-04 t hat you'll 12 hear about f or a couple of hours. A nd included in 13 that discussion will be some recent example th r o u gh 14 tabletops that were done with various designs.
15 And then we'll come back, the staff will 16 come back to spe c i f ically t alk about the draft SECY 17 and t he draft reg guide because i n the e nd t he ACRS is 18 here to make r e c ommendations or observations on the 19 staff's activities.
Those a re the two t hings t hat we 20 plan to issue and so we will be asking at the December 21 meeting for a letter at least on the SECY paper and at 22 y o ur discretion either o n the draft guide or a n 23 acknowledgme nt that you'll get a nother shot at the 24 guide after we address public comments a n d the 25 Commission's decisions on the SECY paper.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 80 1 So w i th that I apologize for being a 2 little late.
3 ACTING CHAIRMAN CORRADINI:
No, w e're 4 good. Final questions from the members.
5 MEMBER KIRCHNER:
Yes. Bill, s ince you're 6 trying to do this technology-inclusive I would suspect 7 that first m ov e r s may not be n on-LWRs but LWRs for 8 many of the issues that you're addressing.
9 So i n your tabletop exercises have you 10 tried to walk through with an advanced LWR design --
11 I'm not saying NuScale, I'm thinking just a n advanced 12 design to just conceptually since as you said you're 13 doing methodology and process. J u st to see how it 14 works.15 MR. RECKLEY: We haven't. If someone were 16 to come forward I guess we could entertain it.
17 The dilemma that you get i n and I'll take 18 NuScale a s the most recent e x a mple. Since they 19 started largely with the existing str u c t u re and how 20 they did the design and the arguments i t gets a little 21 difficult to then apply this methodology that's 22 intended to be used both during the design process and 23 the license application process.
24 It was don e f o r a large light w ater 25 reactor but N UREG-1860 i ncludes an appendix where they NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 81 1 tried to d o t his exercise for a large light w ater 2 reactor and they ran into some of the same problems.
3 And b y the w ay the same problems the staff and 4 industry have faced for the l ast 30 years on trying to 5 undo a methodology that was based so heavily on that 6 large break LOCA and how i t was incorporated both into 7 the design and into the licensing structure.
8 So, the short answer is no, we haven't 9 really entertained it. And the only way we could do 10 it is if s omebody came forward and asked for us to do 11 it, a developer.
For example, one of the other l ight 12 water SMR developers.
13 MR. SEGALA: This i s John Segala from the 14 staff. But the focus of this, the NEI document and 15 our draft guide is on non-light water reactors. So, 16 when we say technology-inclusive we're referring to 17 the different non-light water reactor designs that are 18 out there versus light water reactors.
19 MR. RECKLEY: That was actually the w hole 20 intent of saying technology-inclusive versus the old 21 term of technology neutral.
22 ACTING CHAIRMAN CORRADINI:
Walt? Follow-23 up?24 CHAIRMAN BLEY: This i s D ennis. This 25 bothers me a bit. And maybe Karl will talk about it NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 82 1 at the next session.
2 I'm not sure w h a t I see t hat is non-LWR 3 specific about any of this material.
4 MR. RECKLEY: I don't think we're trying 5 to say i t could not b e used. We're simply saying that 6 the target a udience that we're developing this for and 7 the c ommunity that's been engaged w ith us is the non-8 light water community.
9 I don't think we would disagree, and Karl 10 can weig h i n later, that t hese notions w ould 11 potentially apply to a l ight water SMR b ut that's not 12 what we're trying to develop.
13 ACTING CHAIRMAN C ORRADINI:
Dennis, all 14 right?15 CHAIRMAN BLEY: Okay.
16 ACTING CHAIRMAN CORRADINI:
Okay, why 17 don't we take a break till quarter of.
18 (W h e r e u p o n , t he a bove-entitl e d m a t t e r w e n t 19 off the record at 10:28 a.m. and r esumed at 1 0:44 20 a.m.)21 ACTING CHAIRMAN CORRADINI:
Okay, why 22 don't we try to come back together here and start our 23 next session.
24 Which Michael is going t o lead u s off. 25 Mr. Meier --
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 83 1 MR. AFZALI: Actually I'll start us off.
2 ACTING CHAIRMAN CORRADINI:
Oh, I'm sorry, 3 Amir. I apologize. I was looking over there by the 4 computer. Go ahead.
5 MR. AFZALI: G ood m ornin g. It's a 6 pleasure t o be h ere again. We have based on o ur last 7 conversation, June conversation, Dr. Bley a sked u s to 8 come back and have a detailed conversation about the 9 proposal w e are making. And we have put a great team 10 together to come and answer your questions.
11 We look forward t o your i nsightful 12 comments.
We thought i t would be appropriate for our 13 utility represen t ative to say a few words before 14 starting the conversation.
15 To that end I've asked D r. M eier, a 16 regulatory affairs VP and Mr. Steve N esbitt, I'm g oing 17 to r e a d his title, director of nuclear policy and 18 support, to say a few words. So, Dr. Meier.
19 MR. MEIER: G ood morning a nd t hank you all 20 for the opportunity to appear before the ACRS Future 21 Plant Designs Subcommittee.
22 Southern Company has 46,000 megawatts of 23 generated capacity and provides clean, safe, reliable 24 and affordable energy to its -- throughout our service 25 territory.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 84 1 What's i mportant to note, our C EO Tom 2 Fanning announced to our generation fleet that we have 3 a goal to be low to no carbon by the year 2050. And 4 he has set some goals in between there.
5 In order to do t his we're going to have to 6 focus on technologies that will a llow u s to reduce 7 these carbon emissions. With nuclear energy, and we 8 have talked about this a l ot i n t he company, i s g oing 9 to play a major role in that.
10 Regulatory modernization, however, is 11 going to be necessary for us to remove any of t hese 12 unnecessary challenges a nd reduce inefficiencies in 13 order to make this happen.
14 NEI 18-04 proposals provide a robust 15 systematic and a flexible foundation for modernizing 16 the regulatory requirements for these advanced light 17 water reactors.
18 Given all the variety we have on t hese 19 non-light water reactor designs being developed by the 20 advanced reactor community it's imperative that we 21 h a v e a good foundation a s well as a follow-on 22 regulations made available to the developer c ommunity.23 We a r e encouraged and we are excited by 24 the cooperation b etween the NRC, D OE and t he industry 25 to take concrete steps toward developing this NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 85 1 foundational framework and we look forward to the ACRS 2 suggestions to make the products even better as well 3 as expediting endorsement by the NRC.
4 Finally, I would like to thank t he NRC 5 staff, DOE management, o ur developers and t he industry 6 partners for diligently and effectively g etting us to 7 where we are today.
8 Again, I want to thank you f or your t ime.9 MR. NESBIT: Good morning and thanks for 10 the opportunity to appear before the ACRS Future P lant 11 Designs Subcommittee.
12 So w h y are we h ere. At the risk of 13 repeating the obvious t he current nuclear p ower 14 reactor regulatory framework dating f rom the nineteen 15 seventies and even before has proven to be effective 16 although not always efficient in providing adequate 17 protection to public health and safety.
18 This project is about l everaging 19 knowledge, experience a nd technological advances over 20 the past 50 years to put in place a methodology that 21 will work in the 21st century w hen applied to the 22 range of innovative and diverse reactor designs many 23 of which bear little resemblanc e t o t he light w ater 24 reactors we've become so adept at operating today.
25 Duke Energy, the nation's second largest NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 86 1 nuclear power plant operator, supports the licensing 2 modernization project. The 2017 Duke Energy climate 3 report to s h a reholders o utlines a scenario i n w hich 4 our company would achieve a 72 per c e n t r eduction in 5 CO2 emissions by the y e a r 2050 compared to 2010 6 levels.7 In addition to p hasing out c oal-fired 8 electricity generation this scenario envisions 9 preserving generation from all 1 1 currently operating 10 reactors, increasing energy efficiency, expanding 11 renewable generation, expanding energy storage and 12 deploying i nnovative t echnologies we refer to as zero 13 emitting load following resources, or ZELFRs.
14 A ZELFR has essentially n o carbon 15 emissions, can generate power continuously and can 16 adjust its output to match load.
17 To meet c ustomer n eeds in this scenario 18 Duke Energy analyses indicate 13 percent of our year 19 2050 generation will need t o come from t hese Z ELFR 20 technologies that may not exist today.
21 Nuclear power generation has b een a g reat 22 asset for Duke Energy and its customers in N orth 23 Carolina a nd South Carolina and w e believe advanced 24 reactors are good candidate ZELFR technologies.
25 There are of course challenges to the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 87 1 deployment of advanced nuclear generation.
On e of 2 those challenges is the need for a modern, flexible, 3 adaptable regulatory framework.
4 For innovative and diverse nuclear power 5 reactor d esigns we must h a v e a methodology that 6 continues to provide a dequate protection of public 7 health and s a f ety and w orks in a timely and 8 predictable manner.
9 NEI 18-04 is a key found ation for that 10 regulatory framework about w hich you have h eard 11 already today and you're going to hear more.
12 I've been encouraged by t he progress made 13 to date on this endeavor and in particular on the 14 constructive engagement I've seen among industry, 15 national laboratories, the Nuclear R egulatory 16 Commission staff and other stakeholders.
17 And our t eam looks forward to receiving 18 your observations and insights.
19 MR. AFZALI: M ike, d id you want t o add 20 anything?
Okay. So you heard w hy we are h ere. We 21 are excited to demonstrate to you the how part.
22 And we have a team of three who sit at the 23 table and a team of contributors sitti n g in the 24 audience to answer any d etailed q uestion y ou m ay h ave.25 With that said we're going to l e a v e and NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 88 1 bring the real team over to the table.
2 ACTING CHAIRMAN CORRADINI:
The technical 3 team versus the leadership team.
4 MR. TSCHLITZ: Good morning. My name is 5 Mike Tschlitz.
I'm the senior director o f new plants, 6 SMRs and advanced reactors a t N EI. Thank you for the 7 opportunity t o c ome before t h e ACRS and give this 8 presentation.
9 So, one of the objectives of my 10 presentation here today albeit v ery s h o r t i s to 11 discuss the importance of this initiative and NEI 18-12 04 and to t he overall v i s i o n for w here the industry 13 needs to head.
14 To p aint that pictu r e I'll point to the 15 paper that's on the s lide. It's entitled Ensuring the 16 Future of U.S. Nuclear Energy: Creating a Streamlined 17 and Predictable Licensing Pathway to Deployment. It 18 was issued January 23rd this year and cosigned out by 19 NIA, NEI and NIC. Sent to Chairman Svinicki.
20 And it laid out the near term regulatory 21 reforms that the industry saw as being necessary for 22 licensing advanced reactors.
23 And we'll go through all o f these but the 24 second bullet there talks about aligning the 25 regulatory framework for advanced reactors with our NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 89 1 inherent advanced safety and that's what i n part w e're 2 trying to accomplish through NEI 18-04.
3 In t his p a per we also provided a vision 4 for the future with a m odernized NRC licensing process 5 where th e reviews of a dvanced reactors become more 6 efficient and t imely while continuing to protect 7 public health and safety.
8 The methodology in NEI 18-04 will play a 9 large role in enabling a technology-inclusive r isk-10 informed and performance-based approach, a more 11 safety-focused and predictable regulatory review 12 process and u ltimately t he licensing and deployment of 13 innovative and safe nuclear technologies.
14 MEMBER REMPE: Mike, I had a couple of 15 questions about this slide.
16 First of all, this comment about the t rend 17 of increasing costs. And I looked at slide 28. And 18 although it's good for exciting some folks on the Hill 19 I'd suggest that maybe it's incomplete.
20 For example, I believe the APR 1400 if you 21 had that cost might show a difference in trend. And 22 in fact, in general when you already have an operating 23 plant like t h e s y s t e m 8 0 as well as the APR 1400 I 24 think the staff has done things m o r e efficiently.
25 It's sometimes maybe d esign incompleteness that is NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 90 1 leading to increased costs.
2 MR. TSCHLITZ:
Sure. The information that 3 we're using was based upon informatio n t h a t was 4 reported to Congress i n 2015 o ver t h e l ast 20 y ears 5 for t he r eviews and it showed a f our time increase in 6 the cost of reviews.
7 That being said the staff deserves some 8 credit. I mean, the NuScale review and the APR 1400 9 reviews are proceeding o n schedule.
The A P R 1400 10 review as you know is basically an u p r ate of an 11 existing design so it's k ind of in a different 12 category.
So to say that's a c o m p letely new and 13 different design that you can compare apples t o apples 14 for the cost would be a challenge.
15 But for NuScale, if you look at the cost 16 of the design reviews for NuScale they're approaching 17 and predicted to be about the same as ESBWR for a 18 design with about one-third of the safety systems.
19 So y ou're wondering
-- and a m u c h l ower 20 overall r isk p rofile. S o, I think what we're finding 21 is t he staff is becoming more t imely in i ts reviews as 22 evidenced by APR 1 4 00 and NuScale review, but the 23 efficiency associated with t hat we're not seeing. So 24 that's the basis.
25 MEMBER REMPE: Everyone could improve, NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 91 1 I'll agree with you, but I just was thinking that that 2 chart is a little incomplete.
3 MR. TSC H L I T Z: So if you go to the next 4 slide.5 MEMBER REMPE: Actually, I have another 6 question too.
7 MR. TSCHLITZ: Okay.
8 MEMBER REMPE: This last b ullet, providing 9 additional flexibility for changes during 10 construction.
And I'm th i n k ing about w hat happened 11 with another certified design where some issues were 12 identified and they had t o change during construction.
13 And it's e xpensive to change a certified design u nder 14 Part 52. What are you thinking about doing here?
15 MR. TSCHLITZ:
So if I can go to t he next 16 slide I'll refer to a paper h ere. So the p aper in the 17 lower right-hand corner of this slide, Assessment of 18 Licensing Impacts -- I can't even read it myself.
19 MEMBER REMPE: On Construction.
20 MR. TSCHLITZ: On Construction. So it's 21 a paper that we recently issued that looks at the 22 experience with -- it s tarted with the V ogtle a nd the 23 Summer plants but ended up just looking at the Vogtle 24 3 and 4 constructions about all of the license 25 amendments that had to be i ssued d uring construction.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 92 1 And we did a review along with Southern.
2 Southern w as very instrumental i n us being able to 3 develop th e d ata to support the conclusions i n this 4 report.5 We found that a l ot of the c hanges in the 6 licensing had no safety i mpact. And they were 7 basically c ausing additional costs b ecause of the 8 staff that's necessary t o be maintained basically 9 around t he c lock so you don't impact construction when 10 you find an issue t hat requires some type of 11 disposition that may require an amendment.
12 So t he ongoing carrying costs and then the 13 cost of writing amendments and having the NRC review 14 them is not justified from a safety perspective. So 15 there's these additional carrying c osts for having the 16 ability to make changes to the licensing basis on an 17 ongoing basis throughout the construction p eriod w here 18 the vast majority of the changes had no real 19 connection to safety.
20 And so I would point out that that's a 21 report that you c an r ead and see all t he details. We 22 provide some specific examples in there. We look at 23 tier 2 star information.
We look at the level of 24 detail that's provided for s ome o f the c ivil 25 structural part of the licensing basis.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 93 1 We're basically suggesting that there be 2 a reconciliation process during construction that 3 allows a period of time w here the co n s truction 4 continue in non-conformance with the licensing basis 5 and all o w a period o f time for some development and 6 submittal and the NRC review of a change w hile 7 construction continues.
8 That goes a t t his. That was not going to 9 be the subject of this talk today.
10 MEMBER REMPE: Sure, I just was curious so 11 thank you. I'll look at the paper.
12 MR. TSCHLITZ:
Okay. So o n this s lide as 13 I noted i n the January 23 paper w e set priorities for 14 what needs to get done in the near term.
15 The four documents s hown on this s lide 16 were written over the past n ine months a nd provide 17 recommendations for making regulatory reviews more 18 safety focused and efficient, providing guidance for 19 developing a regulatory engagement plan that supports 20 staged l icensing, proposing a process for providing 21 additional flexibility during construction under Part 22 52, and the t opic we're here to discuss t oday, NEI 18-23 04 which provides a technology-inclusive risk-informed 24 performance-based guidance for identifying licensing 25 basis events, SSCs, and dete r m i n ing the adequacy of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 94 1 defense-in-depth.
2 M E M BER KIRCHNER:
Can I ask you to go 3 backwards?
4 MR. TSCHLITZ: Certainly.
5 MEMBER KIRCHNER:
Since you highlighted it 6 in yellow aligning the regulatory framework for 7 advanced reactors with t heir inherent enhanced safety. 8 I think I know where y ou're going with that but it 9 would seem to me that t he regulator r equires the 10 applicant t o demonstrate the inherent enhanced safety. 11 That's not a given going i n even though on paper many 12 of the designs look promising.
13 I'm just quibbling w ith your choice of 14 words. If I were in your shoes I'd want to expedite 15 my way through the s afety review with a f o c u s on 16 safety and what's important to safety and risk.
17 This sounds like r etooling the r egulatory 18 environment because we think these reactors have 19 enhanced safety features yet to be demonstrated. It 20 seems to m e t hat's n ot your real o bjective.
Your 21 objective is to demonstrate that t h e s e reactors are 22 indeed l ower risk, they have more margin and therefore 23-- I'm just struggling with the words there because on 24 paper it's incumbent on the applicant t o make that 25 demonstration that they really do provide an enhanced NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 95 1 level of safety.
2 MR. TSCHLITZ: So, I agree with what you 3 say. I think what we are trying to communicate t here 4 is -- I'll give you two examples.
5 Consequence-based emergency p lanning. If 6 you make changes to the regulat i o n that allow b ased 7 upon t h e consequences associated with events to set 8 the EPZ as appropriate that's a ligning the r egulatory 9 framework with enhanced safety.
10 Consequence-based s ecurity measures.
11 A l igning the security a t the site with its enhanc e d 12 security f eatures. F or advanced reactors that's 13 changing the framework.
14 So those are the type of changes I think 15 we were after. And this NEI 18-04 also fits in that 16 category whereas you're l ooking at a different 17 approach to determining l icensing basis events that 18 basically wil l f ocus on the most important parts or 19 aspects of the design.
20 MEMBER KIRCHNER:
Let me r epeat my 21 question to Bill f r o m the last session. Is your 22 docu m e n t going to be amenable to an LWR b ased 23 technology?
24 MR. FLEMING: Well, we never intended this 25 to apply to an existing l ight water reactor. If an NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 96 1 advanced non-light water reactor came forward with 2 safety characteristics that were essentially the same 3 as a light w ater reactor using -- r el y i ng on an 4 inventory of coolant, metallic fuel, r eactor vessel 5 and so forth a nd a leak tight containment the process 6 should accommodate such a design approach.
7 We didn't intend i t to exclude any 8 technology but we didn't int e n d i t to b e applied to 9 light water reactors.
10 MEMBER KIRCHNER:
Again, a t risk of 11 r e peating m yself the first movers may likely be L W R 12 designs that will challenge s o me of the existing 13 policies.
And we have such an application for an 14 early site permit before us to look at doing more of 15 a risk-based and performance-based approach to the 16 emergency planning zone as an example. Thank you.
17 MR. TSCHLITZ:
So Jason, if you c an go to 18 my banner sli d e. So t his slide reflects NEI's near 19 term a ctivities w hich h ave been f ocused on the topics 20 on the four banners shown on this slide.
21 And the risk-informed performance-based 22 technology-inclusive approach of N EI 18-04 has 23 impacted the areas that I've highlight e d i n red 24 circles that don't r eally show up that w e l l on the 25 slide here b ut I'l l talk b riefly about each one of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 97 1 those.2 In the area of safety-focused reviews 3 experience over t he last t wo decades with the DC, COL, 4 and ESP a pplications indicates t hat the NRC staff has 5 to a l arge extent remai n e d d e terministic in its 6 licensing reviews even though regulation and guidance 7 allow the NRC staff flexibility to adjust its review 8 on the basis of safety significance.
9 Costs of ongoing NRC reviews remain high 10 leading to t he conclusion that the advantages of s afer 11 designs a ppear to be of little b enefit w hen trying to 12 reduce regulatory r e vi e w costs. Future NRC reviews 13 should better utilize risk information in combination 14 with the principles of defense-in-depth and 15 maintenance of safety margins.
16 In the area of risk-informing advanced 17 reactor licensing basis, information included in the 18 licensing basis t hat doesn't have a connection to the 19 safety basis in the NRC's determinati o n of adequate 20 protection imposes a burden on applicants who h ave to 21 invest resources to develop the in f o r mation and pay 22 for the NRC to review unnecessary content.
23 In addition, t here a re ongoing c osts 24 associated with maintaining and evaluating changes to 25 this information over the life of the plant.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 98 1 Content that is not needed to demonstrate 2 compliance with regulations a nd/or la c k s a n exus to 3 subsequent NRC oversight poses a regulatory burden 4 with no benefit to safety. Inclusion of t h is 5 information during initial certification or licensing 6 is not necessary.
These p ractices increase licensing 7 review costs without a corresponding i ncrease in 8 safety.9 NEI 18-04 provides the starting point for 10 adjusting the content of applications and the focus of 11 NRC's review based upon safety a nd risk significance.
12 Reversing the trend. In this a r e a data 13 submitted to Congress in 2015 shows the costs of NRC 14 reviews have increased substantially over time.
15 As I mentioned briefly the NuScale example 16 demonstrates that the projected licensing f ees of 17 advanced r eactor designs are similar to o t h e r l arge 18 light water reactors.
19 These design certification review c osts 20 have been normalized to 2017 dollars and have 21 increased by a factor of approximately four over the 22 last 20 years.
23 This shows that the advantages of s afer 24 designs have not resulted in reduction of regulatory 25 review costs.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 99 1 CHAIRMAN BLEY: Mike, t his is D ennis B ley. 2 Can you t ell m e anything about t he success or failure 3 of applicants w ho have challenged the st a ff that 4 things t hey're looking at are not important to safety?5 MR. TSCHLITZ:
That's a good question.
6 I'm probably n ot in the best position to answer t hat, 7 but I can offer one example.
8 For the NuScale r eview, the chapter 9 9 a u x i liary s ystems which have no impact on safety or 10 mitigating beyond design basis e vents. I guess it was 11 earlier on in the review and I'm sure this information 12 has changed as the review has continued and s hifted on 13 to chapter 15.
14 But at one point in time 30 p ercent of the 15 staff's RAIs w ere focused on chapter 9 issues. 16 Chapter 9 as I said has no real nexus to safety.
17 So I think t he v i s i on w ould be in the 18 future for t h o s e t ypes of s ystems that don't h ave a 19 direct connection to the safety case there would be a 20 high-level description without a lot of detail in the 21 application.
And that s hould be s u f f icient f or the 22 staff's understanding of the design.
23 So at this point --
24 CHAIRMAN BLEY: That doesn't really get at 25 what I was trying to a sk. Y ou showed increases in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 100 1 costs over quite a few y ears and d uring t hat time have 2 the applicants tried to challenge NRC in t hese areas? 3 Or do they just kind of go along with it?
4 MR. TSCHLITZ:
Well, I don't k now if I can 5 offer a r eally good answer to that q uestion because it 6 involves a lot of different applicants over a long 7 period of time.
8 I can say in g eneral that there is a 9 reluctance to challenge the NRC in some of these a reas 10 during the course of a review.
11 C H AIRMAN BLEY: I'm not sure that won't 12 continue even with this new f ramework so s omething to 13 think about.
14 MR. TSCHLITZ:
I think the framework h elps 15 focus the discussion.
So if y ou can show things more 16 in black and white as y ou can on the frequency 17 consequence curves as you'll see when you look at the 18 results of t he tabletops it helps focus t he d iscussion 19 I think on the issues.
20 So a t t h is p oint in my p r esentation I'm 21 going to make so m e i ntroductions and invite some 22 people who come to the meeting to support us to come 23 to the mike and introduce themselves and explain t heir 24 connection to the project.
25 So the first person is J im Kinsey from NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 101 1 Idaho National Lab.
2 MR. KINSEY: G ood morning. I just wanted 3 to make a couple of remarks related to -- I know the 4 NGNP project came up earlier in the day.
5 Back during that discussion we developed 6 a process based on inputs from the three modular HTGR 7 developers in the U.S. a nd a lso partnered with Entergy 8 at t he time to get some insights from an owner-9 operator organization.
10 And the risk-informed performance-based 11 approach that we presented to this subcommittee back 12 at t hat t ime w as intended to work toward our marching 13 orders o f moving gas r e a c t ors forward, but it was 14 alwa y s envisioned that it could be a technology-15 inclusive process.
16 So o ur i n v olvement with L MP h as been to 17 bring some of that history to bear, provide insights 18 from those previous reviews and as y ou'll see as we go 19 through the d ay the c urrent team is m uch larger, 20 includes NEI, includes tabletops and evaluations from 21 other technology types and includes other owner-22 operators. So it's provided some, as Bill mentioned 23 earlier, some tweaks and refinements t o that original 24 process but it's still l argely based on t he f oundation 25 from that prev i o u s review. So we appreciate your NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 102 1 insights today.
2 M E M BER REMPE: Jim, did the NGNP -- I 3 can't remember.
Did it have t his integrated decision 4 panel as part of that process?
5 MR. KINSEY: I d on't know that it had that 6 discussion in detail. I think t h a t concept was out 7 there, but I think one o f the refinements that was the 8 more significant one in the L M P approach is further 9 defining the details of the defense-in-depth strategy 10 and how you go about a c t ually implementing and 11 managing i t. Th a t's probably one o f the more 12 significant additions t h a t we'll talk about. O ther 13 questions?
14 M R. TSCHLITZ:
Thanks, Jim. The ne x t 15 person is Ed W allace, consultant to Southern Company.16 MR. WALLACE: G ood m orning. M y name i s Ed 17 Wallace. I've been involved with advanc e d reactors 18 since 2001 th r o u gh the PBMR NGNP t echnology neutral 19 framework and NuScale activities.
And a member of the 20 ANS Standards Board focused on risk-informed 21 performance-based practices within the standards 22 community.
23 Part of my purpose with the consultation 24 to S outhern is to bring that experience to bear in the 25 evolution of t his process w hich stems back 35 years or NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 103 1 more to the MHTGR days.
2 My r o l e has been to focus on the 3 discussions aspect of i t b ecause of the comments that 4 have already been made and t h e n e ed to provide a 5 practical way to perform that assessment i n a 6 consistent manner and c onsistent with the r isk-7 informed performance-based information t hat's derived 8 in the other activities that you're hearing about.
9 If y ou h av e a ny questions today I'll be 10 glad to answer them. Thank you.
11 MR. TSCHLITZ:
T h a nks, Ed. The next 12 person is on the phon e line. Brandon Waites of 13 S outhern Company. And he's going to be speaki n g o n 14 behalf of X-Energy.
15 MR. WAITES: Yes, this i s Brandon Waites. 16 I'll just take a quick p ulse to make sure everyone can 17 hear me.18 MR. TSCHLITZ: Brandon, just give us one 19 m oment to t urn off area m ikes so we d on't g e t 20 feedback. Thank you. Brandon, please go ahead.
21 MR. WAITES: O ka y , t hank you. I really 22 appreciate the opportunity to speak today. My name's 23 Brandon Waites. I'm new projects m anager a t Southern 24 Company and I wanted to speak j ust real q u ickly on 25 some a ctivities w e had regarding the LMP earlier this NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 104 1 year.2 Earlier this year the LMP team completed 3 the f irst d emonstration of the LMP process using a 4 real world example with the X-Energy high temperature 5 gas cooled reactor design.
6 And for t his I'd like to t a ke a q uick 7 minute to mention that the LMP team is grateful to X-8 Energy for their support and allowance and significant 9 support of this demonstration.
10 Just to get quickly to the o utcome of the 11 demonstration we con c l uded in a r eport that is 12 publicly available that the demonstration was 13 successful a nd produced several actionable insights 14 both in the a rea of -- for the LMP process itself and 15 also insights into the X-Energy high temperature gas 16 cooled reactor design.
17 ACTING CHAIRMAN CORRADINI: Brandon, can 18 you give us a reference so the staff can g et us a copy 19 of that report? I'd be interested in seeing that.
20 MR. REDD: Michael, this is Jason Redd 21 from Sou t h e rn. We'll g et you that reference 22 momentarily. We've got it available. We'll provide 23 it to a member of the ACRS staff before we l eave 24 today.25 ACTING CHAIRMAN C ORRADINI:
T hank you. NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 105 1 Thank you very much.
2 MR. TSCHLITZ:
Thanks, Brandon. The next 3 person is Gary Miller from GE-Hitachi.
4 MR. M ILLER: Good morning. I'm Gary 5 Miller, m ana g e r of PRA at GE-Hitachi.
W e're 6 responsible for all PRA aspects including design and 7 licensing.
8 We used our PRA of the PRISM sodium fast 9 reactor a s a basis for s upporting two o f the LMP w hite 10 papers on PRA and LBE selection a nd also we used it to 11 demonstrate the methodology that we're going to talk 12 about today. I'll be h a p p y to answer any questions 13 you might have.
14 MR. TSCHLITZ:
T hanks, G a ry. The next 15 person is Steve Krahn from Vanderbilt University.
16 MR. K RAHN: G ood m orning. I'm S teve 17 Krahn. I head up the nuclear environmental research 18 group a t Vand e r b ilt University w here we do risk and 19 hazard assessment on advanced nuclear technology.
20 Specific t o the subject of t oday's meeting we have 21 been involved for the last four and a half years d oing 22 hazard a nd r isk assessment of molten salt reactors and 23 two of the outcomes of that research are part of the 24 package that will be briefed this afternoon.
25 MR. TSCHLITZ:
Thanks, Steve. T h e next NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 106 1 person is Dave Grabaskas from Argonne National Lab.
2 MR. GRABASKAS: I'm Dave Grabaskas. I'm 3 a principal risk analyst a t Argonne N ational Lab. I'm 4 also the vice chair of the ASME AN S n o n-light w ater 5 reactor PRA standard.
6 I w a s a lso the Argonne lead for the 7 collaboration with GE to update the PRISM SFR PRA. In 8 advance of issues we see w i t h advanced reactor 9 licensing our research has focused on passive system 10 reliability, mechanistic source term and d eveloping 11 component reliability databases for advanced reactors.12 And particularly applying them to the NEI 13 framework b ut also its predecessors too with the NGNP 14 and N UREG-1862.
So I'd be happy to answer any 15 questions you have in those areas.
16 MR. TSCHLITZ:
Thanks, Dave. And the last 17 person is Jim August from Southern Nuclear.
18 MR. A UGUST: Good m orning. My name is Jim 19 A u gust. I'm with Southern Nuclear at Vogtle. I'm 20 very excited to be here.
21 The reason I'm h e r e is in my first post 22 Navy commercial job I started off as a reliability 23 engineer a t Fort St. Vrain in 1981 and worked at Fort 24 St. Vrain through about 10 years of operations and did 25 a lot o f work trying to reso l v e t e chnical issues as NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 107 1 well as licensing issues t hat surrounded that high 2 temperature gas reactor prototype commercial plant.
3 As a result of those experiences when the 4 ANS decided to reconstitute and redevelop t heir 5 standard for safety design of high temperature gas 6 reactors w hich are now termed m o d u lar h elium cooled 7 reactors I volunteered to join that committee.
8 From 2004-08 I was a member, 2 008 I became 9 the chair and we completed the s tandard ANS 5 3.1 w hich 10 led to a lot of the work we're discussing here which 11 was the s a f ety design standard for modular helium 12 cooled reactors.
13 My motivation f or doing that work was 14 large l y the e xperience I g ained at Fort St. V rain 15 which included a significant a mount of frustration 16 that related t o us continually being judged i n what I 17 will call a light water reactor environment.
I'm here 18 to answer any questions that you might have.
19 MR. TSCHLITZ:
S o a t this point I'll turn 20 it over to Jason Redd.
21 MR. REDD: Thank you, Mike. Good morning. 22 My n ame i s Jason Redd from Southern N uclear Operating 23 Company. I'm pleased to be here with you all today, 24 members of the committee.
25 The LMP methodology is ultimately focused NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 108 1 on establishing a systematic, coherent framework for 2 establishing a technology-inclusive risk-informed 3 performance-based aspects of the licensing basis.
4 Given t he wide variety of non-light w ater 5 technologies that are p roposed on the r elatively near 6 horizon a t op down path of esta b l i shing technology-7 inclusive methods to establish compliance requirements 8 such as the NEI 18-04 document, the advanced reactor 9 d e s i gn criteria which were released last year a fter 10 collaboration between NRC staff and t he Department of 11 Energy leading to methods f or establishing t echnology 12 specific requirements such as the high temperature gas 13 reactor and sodium fast reactor design criteria 14 contained within the advanced reactor design criteria 15 both leading to reactor design specifi c design and 16 compliance basis, for example, the principle design 17 criteria is an appropriate and effective pathway.
18 NEI 18-04 guides prospective applicants in 19 answering the following q uestions.
And we're going to 20 come back to these questions again at the end of the 21 presentation so certainly stay tuned through Karl.
22 What are the plan initiating events, the 23 event sequences and accidents t hat are associated with 24 that p articular r eactor design, how d oes the proposed 25 design and its structured systems and c omponents NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 109 1 respond to initiating e vents a nd event sequences, what 2 are the margins provided by the facility's response.
3 Again we've heard in the Commission's 4 policy statements the margins are of significant 5 interest both to the Commission and to the staff and 6 to t he designer a n d o perator community as t hose 7 margins relate to the prevention and mitigation of 8 radiological releases within prescribed limits f or the 9 protection of the public health and safety.
10 And is the philosophy of defense-in-depth 11 a d equately reflected i n the design and operation o f 12 this facility.
13 With these opening remarks I'll now turn 14 it over to our technical lead --
15 MEMBER REMPE: Just a second, I h ave a 16 question.
17 MR. REDD: Yes.
18 MEMBER REMPE: To make sure I understand 19 because I did find when I l ooked through t he document 20 you're considering low p ower and shutdown events, 21 you're considering external events. Hazards 22 associated with the spent f uel p ool. That should also 23 be considered.
24 And then later on whe n y ou get to the 25 tabletop discussions, did t hey have PRAs that NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 110 1 considered all those types of phenomena?
2 MR. REDD: Let me answer the first part.
3 Yes. The LMP process in NEI 18-04 is designed to 4 address all o f the radiologica l sources within the 5 plant whether that's the reactor vessel -- the primary 6 cool a nt system, spent fuel pool. Obviously some 7 advanced reactor designs also have radionuclide 8 inventory such as off gas holdup vessels and similar 9 or storage tanks.
10 All of those sources of radionuclides that 11 could pose a h azard to the public a re included within 12 the LMP process.
13 I'd like to invite Karl to an s w e r the 14 question about whether the demonstrations we've done 15 so far have included those aspects.
16 MR. FLEMING: I'm not sure if we'll get to 17 it this morning but certainly in the early afternoon 18 I'm going to give you a breakdown of all the s teps of 19 our process and what was exercised and not exercised 20 in each of the tabletops so far.
21 So in general most of the experiences 22 focused on f ull power operation s o the experience base 23 is limited on some of these other sources. But I'll 24 give you more details on that later.
25 MEMBER REMPE: Thank you.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 111 1 CHAIRMAN BLEY: K arl, this is Dennis. 2 Before you get started two things.
3 We did invite you guys back to hear more 4 and more broadly and new m aterial. S o as you go 5 forward i f you can emphasize the new material a nd de-6 emphasize the repetitive stuff that would be great.
7 And number two, back in June we had d raft 8 Mary, M. Now we have draft November.
Has there been 9 any substantive c hanges that you can t ell us a bout in 10 the guidance since the last time we talked with you?
11 And I'll go offline.
12 MR. FLEMING: In respond to your f irst 13 question I'll do my best not to r e peat things that 14 you've s e e n before and try to emphasize the new 15 material.16 I'll invite Jason to comment on revision 17 N versus M.
18 MR. REDD: Good m orning. The changes from 19 draft Mike to draft N o v e mber were primarily the 20 incorporation of comments from this committee in the 21 June time frame.
22 The major changes have been an expansion 23 of the d iscussion o f certain aspects. There was 24 increased discussion especially of h ow defense-in-25 depth is applied.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 112 1 A lot of clarifications here and there in 2 response to b oth staff feedback both i ndustry feedback 3 and the committee's June comments.
4 There was no change whatsoever in the 5 underlyi ng philosophy or the methodology.
I w ould 6 characterize these changes as editorial and 7 explanatory.
8 MR. FLEMING: I'd j u st add one point to 9 what Jason mentioned a nd that is that e ach of the 10 revisions has reflected o u r evolution in being more 11 precise about our terminology.
12 So t he use o f our terminology i n avoidance 13 of synonyms for key terms and cleanup of o ur glossary 14 has continually been improving along the way.
15 Than k y ou very much, Jason. If I can 16 start my talk here. The technical presentation that 17 we have outlined has two parts to it. O n e o f t hem, 18 the first part is to just amplify on some methodology 19 refinements that we made since the NG N P d a ys a nd to 20 point out s o m e technical items t hat fill in some of 21 the gaps from Bill Reckley's presentation.
22 And then the s econd half o f our 23 presentation is geared towards the lessons learned 24 from our tabletop pilot applications.
25 On t his first s lide which outlines the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 113 1 principal focus of this methodology the things that --2 I just wanted to amplify on some of the t hings that 3 Bill Reckley has already mentioned.
4 This is an integrated process for license 5 event selection safety classification and defense-in-6 depth. And they're really inte r r e l ated in terms of 7 the safety classification refers to functions that are 8 performed by the SSCs on the licensing basis events.
9 The defense-in-depth refers back to both 10 the SSC f unctions and the LBEs that a re participating 11 in preventing a nd mitigating accidents.
And the 12 defense-in-depth aspects h ave a lot to do with setting 13 the performance r equirements for our s ystem s tructures 14 and components that come o ut of s afety c lassification.
15 The process leads to a s ystematic 16 identification o f the design basis accidents that will 17 go in c hapter 15 using a process that w e believe is 18 repeatable, reproducible and so far has produced 19 nothing but sensible and consistent results.
20 Uncertainty is a very m ajor f ocus of this 21 activity.
It's addressed within the s tate of the art 22 of PRA i n terms of e stimating frequencies and d oses 23 with their associated uncertainties b ut it i dentifies 24 sources of u ncertainties that are captured and 25 evaluated very c arefully in the i ntegrated decision NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 114 1 processes a ssociated w ith establishing defense-in-2 depth adequacy.
3 The evaluation of plant capabilities and 4 programs for defense-in-dept h i s one of the a reas 5 that's extended beyond w hat was d one in the NGNP 6 process.7 We think this process is risk-informed 8 using Chairman Jackson's original i dea behind that 9 t e r m i n that it involves a balance of probabilistic 10 and deterministic inputs. It's not risk-based by any 11 shape of the imagina t i on but our rationale for 12 starting with a design-specific PRA that's i ntegrated 13 into the design process is it's a way to enumerate a 14 systematic and exhaustive set of scenarios that we can 15 draw from to build the license application.
16 One are a t hat we have enhanced f rom the 17 NGNP days, we've tried to e mphasi z e more of the 18 performance-based aspects of the approach.
19 Performance-based includes using plant level metrics 20 for m easuring the risk significance of licensing b asis 21 events, but also in setting performance requirements 22 for SSC s t h at are phrased in such a way that can be 23 tracked and monitored throughout the plant operation 24 and lifetime to get adequate assurance that a safety 25 case is being upheld.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 115 1 And the other aspect of this approach is 2 that unlike the light water reactor m odel for 3 prevention and mitigation which has been largely 4 focused on preventing core damage and mitigating the 5 consequences of core d amage, t hese reactor designs 6 that we're deali n g w i th have many different end 7 states, many different e vent sequences, different uses 8 of barriers and layers of defense.
9 So finding a general way to talk a bout 10 prevention and mitigation linked to b alancing, 11 preventing a nd mitigating the releases from 12 radioactive material from the plant.
13 If we go on to the next slide. To clear 14 up some of the discussion earlier on how we come up 15 with our des i g n basis accidents, we start with 16 defining acciden t families in which we group e vent 17 sequences according t o the similarity of p lant 18 challenge i nitiating e vent, p lant response and if 19 there is a release mechanistic source term.
20 We group them and classify them by 21 frequ e n c y into three regions. And from that we 22 evaluate t he -- we start with the d esign b asis events 23 and t he d esign basis events region and we look at the 24 design basis event as candidate s f o r design b asis 25 accidents.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 116 1 The idea is that w e w ant to have a 2 reasonably complete enumeration of design b asis events 3 that challenge the safety case.
4 When we g et i nto this part of the analysis 5 the LBEs that have no consequenc e s are equally 6 important if not more important t han the ones that 7 might have a risk significance.
The risk significance 8 is part of this but what we want to mine out of this 9 is what are the features in t he plant that are 10 responsible for preventing releases from t hese 11 accident sequences and then what do I have to preserve 12 in my design basis to enforce that result.
13 ACTING CHAIRMAN CORRADINI:
So can I -- if 14 this is the w rong time to ask a q uestion you c an just 15 hold me off.
16 So is there a standard p rocess i n risk 17 assessment that one understands how to b u n d l e t hese 18 things? Because I know you've said it a number of 19 times and w e said it in June, but I d on't -- I'm s till 20 trying to get a handle on a guidance here that it's 21 perfectly clear what's a good judgment and what's an 22 inappropriate judgment on the bundling.
W hether it be 23 based on source term or based on frequency. Or type 24 of initiator. And I can't tell yet.
25 MR. FLEMING: Okay. We hand l e t h at NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 117 1 through the A N S ASME l ight water r eactor, non-light 2 wate r reactor PRA standard.
There are technical 3 requirements in that standard for defining e vent 4 sequence families and this is fundamental to analyzing 5 the contributors to risk in that framework.
6 S o w e a ctually have -- it's in that 7 standard that was issued for trial u se in 2013. D avid 8 Grabaskas was alluding to o ne of t he pilot studies 9 done to exercise that.
10 ACTING CHAIRMAN CORRADINI: So if I have 11-- pardon if this is too simple, but if I h a v e a 12 stat i o n blackout event as we might have in a l ight 13 w ater r eactor but with a r ange of s ource terms t h a t 14 would all be bundled various station blackout events 15 with various initiators, or would it be more akin to 16 bundling them based on source term?
17 I'm trying to think in my mind that I've 18 got an x-y plot where y is the f requency and x is the 19 source term essentially for all i ntents and purposes.
20 A n d I'm trying to understand h ow you bundle t hese 21 things if I g et a disagreement about how I bundle them 22 based on initiator or source term.
23 MR. FLEMING: Well, first of all we want 24 to b u n d l e them b ased on s ource t erm. If there is a 25 source term we don't want t o h a v e d issimilar source NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 118 1 terms in the same event sequence family.
2 ACTING CHAIRMAN C ORRADINI:
T hat's the 3 first principle.
4 MR. FLEMING: That's one. Then beyond 5 that o f all those that have the same mechanistic 6 source term among those we want to identify t hose that 7 have t h e same challenge t o my safety functions.
So 8 what systems were working, w hat systems weren't 9 working, what functions were fulfilled.
10 So w e w ant t o p reserve t he character of 11 how the safety case was challenged by the event sq.
12 ACTING CHAIRMAN CORRADINI:
So did I miss 13 that, or is that written somewhere in 18-04?
14 MR. FLEMING: No, it's not w ritten in 18-15 04. It's r eferred to in the PRA s tandard, the non-16 light water reactor PRA standard.
17 ACTING CHAIRMAN CORRADINI:
Okay. And 18 that's referred to in 18-04.
19 MR. FLEMING: Yes.
20 ACTING CHAIRMAN CORRADINI: Okay.
21 MEMBER KIRCHNER:
Karl, can I interrupt 22 and ask a question? So you're in the early stage of 23 an advanced design. You can probably bound the source 24 term obviously, whatever the co r e d esign is. But 25 there are design characteristics, I guess I'm asking NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 119 1 an uncertainty question in an indirect way. Without 2 getting into specific designs. Let m e see i f I can 3 phrase this generically. Technology-inclusive.
4 There are things like reactivity insertion 5 accidents, or there are fuel failure modes that e arly 6 on can have a large uncertainty associated with them 7 until you've done the actual detailed design o r you've 8 done a fuel qualification pr o g r a m or et cetera. So 9 how do you best include uncertainty early on so that 10 you don't get down the r oad and find that systems that 11 you thought weren't risk significant or weren't 12 safety-related then you get into a backfit situation 13 of revising y our design well down t he road w hich 14 obvious l y w o u ld be a nightmare for any advanced 15 concept trying to expedite its way through the system.16 So how do you deal with that uncertainty 17 early on when you're going through establishing your 18 design basis a n d other events and then y ou're g oing 19 through it, a nd then you're selecting your safety-20 related systems and such. Then do the DBA analysis.
21 But put the DBA analysis aside.
22 I'm just curious how best in this process 23 you avoid a major redesign, or a major backfit, or a 24 major change in the q uality level o f systems and 25 components as the design matures.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 120 1 MR. FLEMING: Well, let's see. I f you 2 break the LMP process down into its full level of 3 detail it's like an 18-step process. A nd many of 4 those s teps involve e valuations of w h at you h ave so 5 far wit h f e e dback loops t o go back to the beginning 6 when you have to choose the design in order to get a 7 satisfactory result.
8 In the PRA part of this process based on 9 where y ou are in the d esign when you apply the PRA 10 standard roughly h alf t h e r e quirements in the PRA 11 s t a n dard have to do with uncertainties.
H ave to d o 12 with identifying sources of uncertainty, trying to 13 account for them to th e b e s t you c an a nd your 14 estimates of the so u r c e term a nd the frequencies of 15 occurrence.
16 The ones that you cannot handle that way 17 beyond the state of the art to do that then you have 18 to do sensitivity studies. But you have to document 19 all of t he sources of u ncertainty i n the overall 20 process.21 After the PRA has taken its best shot to 22 deal with these in I'd say PRA space when we g et into 23 the defense-in-depth adequacy evaluation the defense-24 in-depth adequacy evaluation looks at these issues of 25 uncertainty, takes a c ritical look at what was done in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 121 1 the P RA, what was assumed in t he PRA, what sources of 2 u n c ertainty were identified in the PRA a nd t h e n 3 identifies compensatory measures.
4 And the compensatory measures could r ange 5 anywhere from changing t h e d e sign to p utting in 6 programs, doing testing, experiments and those types 7 of things.
8 So t he process c ertainly does not shy away 9 from this challenge of uncertainty. And I think the 10 process accommodates it.
11 ACTING CHAIRMAN CORRADINI:
So can I 12 follow up Walt's question?
S o I'm still back to 13 principles of using t his because I'm still kind of 14 muddled about this.
15 You said there are t hree possibilities if 16 you go through your iteration loop. One was to change 17 the design. One was to I'll call it sharpen my 18 pencils and do better anal y s is. One w as to use 19 compensatory measures, some sort of programmatic --
20 MR. FLEMING: Or do testing.
21 ACTING CHAIRMAN CORRADINI: Or testing.
22 MR. FLEMING: Yes.
23 ACTING CHAIRMAN CORRADINI: Okay. So is 24 the principle that if I can do something with low 25 uncertainty and high confide n c e I would choose that NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 122 1 over something with large uncertainty?
2 In other words I might change the design 3 and now I h a v e a hardware f ix that s olves i t with a 4 much smaller b and of u ncertainty.
Is that p referred?5 MR. FLEMING: Well, that would certainly 6 be taken into account in whatev e r decision would be 7 made. It's hard to prejudge.
8 ACTING CHAIRMAN CORRADINI: But it's not 9 necessarily preferred.
10 MR. FLEMING: It's hard --
11 ACTING CHAIRMAN CORRADINI:
I'm g oing 12 somewhere with this, but I'm trying to understand it 13 because it strikes me that unless I start off with a 14 relatively s ophisticated, or some l evel of 15 sophistication in the design and the P RA I'm g oing to 16 have a lot of uncertainty.
17 So the m ore I c an change the design to 18 minimize my uncertainty band the better off I am.
19 MR. FLEMING: Right, but there has to be 20 sort of a c o s t-benefit part of that d ecision-making 21 process to figure out what the most -- I'm reluctant 22 to give a one size fits all answer.
23 ACTING CHAIRMAN CORRADINI:
I understand.
24 MR. FLEMING: Given the different designs 25 and different stages of design and so forth.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 123 1 MEMB E R SKILLMAN:
Karl, let me ask a 2 question here. I'm following your discussion with the 3 material that was presented. You're explaining task 4 4.5 The event s equences modeled and evaluated 6 in the PRA a re grouped into a ccident families each 7 havi n g a similar initiating event, c hallenge to the 8 plant safety functions, plant response and mechanistic 9 source term if there is a release.
10 MR. FLEMING: Yes.
11 MEMBER SKILLMAN:
Now, here's m y question.
12 Can the family assignment affect the PRA's c onclusion 13 or frequency such that random s election will identify 14 a sequence as an AOO one t ime and a DBE a nother t ime?15 MR. FLEMING: I d on't believe -- I believe 16 if the words that you just read are f ollowed properly 17 that shouldn't result in any different classification 18 randomly. I can't see how that would happen.
19 MEMBER SKILLMAN:
So would it be accurate 20 to assume that the family gr o uping is c onsistent 21 whether it's done by PRA analyst A or B or D or Q?
22 MR. FLEMING: That's the reason why we 23 develop s tandards.
T he whole idea of the standard is 24 to create a reproducible process.
25 MEMBER SKILLMAN: Thank you, Karl.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 124 1 MR. FLEMING: Getting back to the slide, 2 after we define the D BEs i n the DBE region t he idea is 3 to h ave a comprehensive set of c hallenges to my safety 4 case.5 And I go through a process a nd I ask 6 myself what are the e ssential f unctions that I have to 7 fulf i l l to keep these design b asis events inside my 8 frequency consequence target that if I did n't have 9 these could easily flow outside the target.
10 And that's when I come up w ith what we 11 call the required safety functions.
These are the 12 required safety functions.
13 Now they relate to t he fundamental safety 14 functions that Bill m e ntioned, b ut e ach reactor has 15 the opportunity to come up with a specialized set of 16 safety functions that fulfill the fundamental safety 17 functions.
So t h i s i s what we call the required 18 safety functions.
19 This was the insight that wa s a l ways in 20 t h e p r ocess but needed better discussion that was 21 fleshed out in the X-Energy pilot demonstration. It 22 led to some substantial enhancements to that part of 23 the process.
24 Then we l ook at, okay, w hat S SCs are 25 available and not available during all the DBEs to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 125 1 perform those required safety f unctions.
And that 2 process leads to presenting the designer with a set of 3 options t hat he can select among thos e t hat are 4 available on the design basis even t s , he can select 5 based on his overall strategies. Another integrated 6 decision process, by the way.
7 He selects the safety-related SSCs t hat he 8 wants to declare safety-related and then we construct 9-- from each DBE we construct a DBA where we remove 10 any credit for the perfo r m a n ce of a ny non-safety-11 related SSC and that leads to a set of DBAs.
12 And this process has now been done for 13 three or four different plants and when we get to the 14 end everybody think s t hat y es, these make sense for 15 this reactor.
16 ACTING CHAIRMAN CORRADINI:
So can you 17 give me an e xample of a list o f r e q uired safety 18 functions that are technology-inclusive?
19 MR. FLEMING: No. The point is --
20 ACTING CHAIRMAN CORRADINI:
I'm 21 strugg l i ng. I'm reading the words. I'm t rying to 22 u nderstand.
B ecause you said X-Energy this i s 23 something that was i lluminated in the tabletop 24 exercise was X-Energy.
So I'm t hinking there would be 25 some required safety functions that are essentially
--NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 126 1 I guess to put it a different way you're identifying 2 safety functions that remove vulnerabilities.
3 MR. FLEMING: That's right. The required 4 safety functions will b e r eact or-specific.
So the 5 fundamental s afety functions t hat Bill talked a bout 6 are generic to all reactors, remove c ore heat, control 7 reactivity and contain fission products.
8 But then when you develop these for 9 specific r eactors, f or example, in the high 10 temperature g as cooled reactor family c ontrolled 11 chemical attack always comes up b ecause that's 12 necessary for the fuel integrity.
They don't want to 13 have oxidation processes go on.
14 We'll show you what the required safety 15 functions were for GE PRISM this afternoon.
16 ACTING CHAIRMAN CORRADINI: Okay, that's 17 fine. If we're going to get to i t later that's f ine. 18 Thank you.
19 MEMBER MARCH-LEUBA:
The s taff 20 presentation had a second bullet what safety functions 21 are required to m aintain the beyond design b asis 22 events t o preven t t hem from going to design b asis 23 event in frequency.
I don't see you addressing t hat. 24 Do you understand my question?
25 They had two bullets on the selection of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 127 1 which structures are safety-related. And the second 2 bullet said if you need a structure to make sure that 3 your beyon d d esign basis event does n ot increase in 4 frequency and b ecomes a DBE. Those seem to be 5 addressing that part.
6 MR. FLEMING: We do t he safety 7 classification, we may hav e a beyond design b asis 8 event that has a very high consequence above 25 rem.
9 So part of t he safety c lassification process is to 10 prevent those BDBEs to go up into t he DBE region. So 11 that's another input to the safety classification.
12 This covers the safety c lassification that 13 comes from mitigating the DBEs.
14 MEMBER MARCH-LEUBA: So you're proposing 15 to do that only for those beyond design basis events 16 that have high consequence?
17 M R. F L EMING: Yes. The goal is to make 18 sure that if there's some degradation in performance 19 of the safety-related SSC that you don't get outside 20 the consequence target.
21 There's two ways to get outside. One is 22 horizontally and the other is vertically. So that's 23 the reason for that.
24 M E MBER MARCH-LEUBA:
But you only do i t 25 for the high consequence events.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 128 1 MR. FLEMING: For safety classification, 2 yes. F or safety classification.
Now t h ere's o ther 3 aspects of t h e frequency consequence that come into 4 the non-safety-related w ith special treatment w hich 5 I'll get to in a second.
6 MEMBER MARCH-LEUBA:
Well, we'll talk 7 about this when you have the figure.
8 MR. F L E MING: Go to the next slide, 9 please.10 MEMB E R SKILLMAN:
Karl, let me ask a 11 question before you go on. I'm back to my homework.
12 Going to read a sentence to you.
13 Part of the LBE frequency dose e valuation 14 is t o ensure t hat LBEs involving releases from two or 15 more reactor m odules do not make a significant 16 contribution to r i s k and to ensure that measures to 17 manage the risks of multi-module accidents are taken 18 to k eep multi-module releases o ut of the list of D BAs.19 MR. FLEMING: Those are design objectives.
20 What you're referring to there are design objectives.
21 And since the beginning of this process 22 which started in the M HTGR days and carried u p through 23 the NGNP part of this d evelopment it's always intended 24 that this is a multi-module application.
25 So rather than worry about the l essons of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 129 1 Fukushima aft e r the fact to worry about what you're 2 going to do about multi-module risk we wanted to get 3 the m ulti-m o d ule treatment built in from the ground 4 floor.5 So what you were just reading is sort of 6 a statement of a design o bjecti v e. It's really the 7 motivation for taking on multi-module event sequences 8 is we want to take them on so the designer was aware 9 of them so he can make decisions a bout sharing 10 equipment.
11 There's b enefits to sharing equipment 12 because it p rovides more backup c apability and 13 redundancy, but there's down s ides associated with 14 maybe introducing the likelihood of a multi-module 15 event.16 So by e mbracing the multi-module 17 considerations in the process we give the designer a 18 tool to manage the risk of multi-module events as part 19 of this design. So that's what that statement is.
20 ACTING CHAIRMAN CORRADINI: Thank you.
21 MR. FLEMING: On the safety classification 22 as Bill mentioned we have three safety classes. The 23 safety-related, the non-safety-related with special 24 treatment and the non-safety-related with no special 25 treatment.
Those are t he three classes that we h ave.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 130 1 The integrated d e c i s i o n p r o c e s s a s s o c i a t e d 2 with defense-in-depth has an impact o n t his because 3 the second category, non-safety-related with special 4 treatment, there's two ways to get in there.
5 One, it's a risk-significant S SC based on 6 some risk significance criteria that are outlined up 7 here, o r t he SSC performs in a function that's 8 considered necessary for a dequate defense-in-depth and 9 t h a t's the result o f a n integrated decision process 10 that l o o k s at the design, that looks a t the 11 redundancy, the diversity, the layers of defense and 12 determines some SSC functions may be c r i t i c al for 13 adequate defense-in-depth.
Those are the two ways to 14 get into NSRST.
15 And that aspect of t he classification 16 process is a nalogous to some aspects in 5 0.69 although 17 I don't want to say we're using 50.69 but that 50.69 18 also classifies safety significant SSCs as r isk-19 significant or defense-in-depth adequacy.
20 ACTING CHAIRMAN CORRADINI: So when it's 21 time maybe i n the afternoon I'd be i n t e rested in an 22 example about the risk-significant or performed 23 functions necessary for defense-in-depth adequacy.
24 I had a hard time in the document 25 understanding the l ogic so a n e xample might h elp in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 131 1 that regard.
2 MR. FLEMING: Ye s. We actually have 3 examples this afternoon for GE PRISM w e can show you.4 O n e of the f eatures of t his approach is 5 the use of what we refer to as absolute risk metrics 6 for risk significance rather than relative metrics.
7 What I mean by that i s in the traditional 8 light water reactor risk-significant approach for 9 operating reactors y ou m easure t he importance of a 10 piece of equipment relative to your baseline result.
11 And i f you have a core damage frequency that's one or 12 two orders of magnitude lower that's not r eflected in 13 the relative importance of the metric.
14 In the ESBWR application they a dopted more 15 of an absolute risk m etric a pproach and we've adopted 16 t h a t here in the sense t hat we m easure ris k 17 significance on how c lose y ou are to the frequency 18 consequence t a r g et as far a s licensing basis events 19 are concerned and h o w far a way you are from the 20 cumulative risk targets that we have.
21 So the risk significance i s tied to 22 stationary numbers that don't change with y our design. 23 And that's a v ery, very important distinction between 24 what w e have for operating light water r eactors and 25 the LMP process.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 132 1 The risk s ignificance criteria by the way, 2 the numerical risk significance criteria is something 3 that was added since NGNP. NGNP did n ot come up with 4 SSC risk significance criteria.
5 ACTING CHAIRMAN CORRADINI:
So, can I say 6 the second m ajor bullet a diffe r e n t way, or the sub 7 bullet in that.
8 What you're really saying is how close to 9 the line can y ou get before something, it alarms you. 10 And you're saying you have to get within --
11 MR. FLEMING: One percent, yes.
12 ACTING CHAIRMAN CORRADINI:
Either in the 13 frequency or in the dose.
14 MR. FLEMING: We l l , 1 percent of the 15 frequency as a function of dose. And I'll show you 16 the chart. It's coming up. I'll show you the chart 17 that shows that.
18 We also screen out doses that are so low 19 that they're a small fraction of background which we 20 talked about in June. Next slide, please.
21 So if we look at the universe of SSCs in 22 the p lant we have all the -- t he rectangle r epresents 23 all the SSCs in the plant.
24 The large oval t here is w hat's modeled in 25 the PRA. And the idea t here is the PRA safety NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 133 1 functions are s u pposed to c apture a ll the SSCs that 2 participate in either preventing or mitigating the 3 release of radioactive material from a ny source, 4 radionuclide s ource. So that's the logic for getting 5 it into the PRA.
6 The safety significant SSCs are those that 7 are r i s k-significant or they provide an adequacy of 8 defense-in-depth.
And therefore the risk-significant 9 is a subset of that.
10 We also have our safety-related SSCs and 11 they're almost always risk-significant but if there's 12 a lot of r edundancy in your a b i l i ty to meet your 13 required safety functions they're not necessarily 14 risk-significant but they're a lways safety-15 significant.
So we refer to t hat as the S e g a la-16 Cubbage d iagram because it resulted f rom a l o ng 17 discussion we had with A my and J ohn abou t h o w t hese 18 things relate.
19 MEMBER KIRCHNER:
Since the point was made 20 of excessive review and time and enhanced cost comes 21 into play can you use this to make an argument that I 22 only need, I'll make up a number, 10 chapters out of 23 the standard application versus 18 or whatever we're 24 up t o in a typical application and the level of detail 25 that's needed for say auxiliary systems.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 134 1 If you can argue that they aren't safety-2 significant or they aren't risk-significant then can 3 you propose a means to t he staff t hat they should fall 4 off the table in terms of the review?
5 MR. FLEMING: Right. We ll, we haven't 6 gone into great detail o n this. The general 7 unde r s t anding is that in the license application we 8 would provide substantial information for the staff to 9 review the safety-significant SSCs and t heir 10 performance.
And the ones that are n o t safety-11 s i gnificant w ould not be described in great detai l. 12 I mean, that would be the intent.
13 The motivation going back to the MHTGR, 14 this process really started with the M HTGR application 15 back in the nineteen e ighties. And the m otivation 16 that General Atomic h ad to l aunch this a pproach is 17 that they wanted to e nd up with a correct set of 18 safety-related SSCs because that was viewed t o be the 19 thing that drove the cost of the facility.
20 They did n't w ant it to be larger or 21 smaller than necessary, but they wanted to get the 22 right set of SSCs. S o that's obviously the m otivation 23 is to not spend a lot of time arguing a nd sending RAIs 24 back and forth on non-safety significant SSCs.
25 And of course within the two categories of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 135 1 safety-related and non-safety-related special 2 treatment the understanding i s, the general 3 expectation is that there would be a lot more focus on 4 the safety-related SSCs given their importance and 5 somewhat less l e v el of detail on the non-safety-6 related with special treatment.
T hat's the general 7 understanding.
8 MR. REDD: I would of course add t hat Bill 9 and Amy will be discussing this topic on application 10 content further this a fternoon.
But I agree with what 11 Karl said. The ultimate goal is to focus o n t hose 12 most safety-significant aspects t hat could affect 13 public health and safety.
14 CHAIRMAN BLEY: This is Dennis --
15 MR. FLEMING: I think D enn i s had a 16 question.17 ACTING CHAIRMAN CORRADINI: Yes.
18 CHAIRMAN B LEY: I want t o make sure I 19 understand your di a g r a m. Things that are safety-20 significant are either risk-significant o r they're 21 needed for defense-in-depth. Is that correct?
22 MR. FLEMING: That's correct.
23 CHAIRMAN BLEY: And in your evaluation of 24 defense-in-depth you're considering the u ncertainty in 25 the performance with barriers and other equipment.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 136 1 MR. FLEMING: That's right.
2 CHAIRMAN BLEY: Okay. Go ahead.
3 MR. FL E M I N G: That's correct. Just a 4 couple of comments about this diagram is that one of 5 the areas that we went a little bit further compared 6 to N GNP is t hat after we had the safety classification 7 how do we come up with special treatment requirements 8 for each of the categories.
9 The thing that's new here in the LMP 10 process i s that we start with both safety-related and 11 non-safety-related special treatment, we start the 12 process by s etting p erformance requirements for 13 reliability and capability.
14 Reliability because if you look at a ll the 15 special treatment requirements you c an sort of get 16 into those two categories.
Some of them give you 17 greater assurance of reliability. Some of them give 18 you greater assurance t hat t hey've got adequate 19 margins when they perform t hat they'll get the job 20 done to perform their function.
21 So we set the requirements for reliability 22 and capability.
Those r equirements are set with i nput 23 from the integrated decision process f or e valuating 24 defense-in-depth.
T hey're looking a t the 25 uncertainties. They're looking at the whole package NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 137 1 of things.
2 We set those requirements including 3 numerical requirements for r eliability and 4 availability and performance requirements. And then 5 the rest of the special treatment flows from that.
6 And for the non-safety-related with 7 spec i a l treatment our thought is that in most c ases 8 all that should be required i s putting i nt o case a 9 monitoring program to monitor t he performance of t hose 10 SSCs against those performance requirements.
11 If there's o ther special treatments or 12 compensatory measures that a re needed the IDP process 13 would identify those whereas i n the safety-related one 14 there w ould be a more e xtensive set of special 15 treatment requirements.
16 So that's an area where we've gone beyond 17 what's actually in the NGNP documents.
18 ACTING CHAIRMAN CORRADINI:
So Dennis 19 actually c larified t he o ne thing abou t w hat safety-20 significan t S SC is. I t's both defense-in-depth and 21 risk-significant together.
22 MR. FLEMING: That's right.
23 ACTING CHAIRMAN CORRADINI:
Where is 24 safety -- oh, I see. Safety-related is t he smaller of 25 those.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 138 1 MR. FLEMING: A nd getting to -- I won't go 2 into the details on this. There's a table 5-2 for 3 example in the guidance document that talks about the 4 minimum r equirements for plant capability defense-in-5 depth. 6 And one of the principles that's in that 7 table is t h a t for r equired safety functions and 8 critical elements of your safety case you can't have 9 over-reliance on a single design feature or a single 10 element o f your design or a single p r o g r ammatic 11 measure to assure that that's fulfilled.
12 Where that leads to is t he need to have at 13 least a couple of different ways to p erform your 14 required safety functions.
15 So all the s afety-related SSCs are 16 definitely necessary for defense-in-depth.
And in 17 most cases they're a lso risk-significant because if 18 they don't perform the ir function you c ould easily 19 have a point creep outside the frequency consequence 20 target.21 ACTING CHAIRMAN CORRADINI: Thank you.
22 MR. FLEMING: The final point I wanted to 23 make on this is that this b ig r e c t a n gle, the change 24 left over after you modeled e verything i n those o vals 25 and everything, there's typically screening done NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 139 1 because the PRA model d oesn't include all the S SCs in 2 the p lant. So t here's all kinds o f s creening 3 assumptions made and screening sometimes b ased o n low 4 frequency or whatever.
5 The integrated decision-making process 6 takes a look at that to say gee, is there some 7 compensatory measure we've got t o put in place to make 8 sure that the assumptions to screen t hat component out 9 of the PRA model is enforced.
10 So that's another example on how this is 11 not a risk-based process. It's -- we get what we can 12 out o f the PRA process but then w e supplement it with 13 defense-in-depth.
14 MEMBER MARCH-LEUBA:
Going back to your 15 previous comment about not over reliance on a single 16 thing. Is that single failure criteria light?
17 MR. FLEMING: It may be, I d on't k now. 18 You may look at it as single failure heavy because the 19 way it's typically manifested i n the examples that 20 we've gone through in t he pilot studies is you end up 21 having diverse -- in some cases you may have passive 22 inheren t f e ature to perform a safety function.
And 23 maybe the second item that's added to the defense-in-24 depth adequacy is an active system.
25 So i t's more likely to result in diversity NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 140 1 rather than redundancy.
However, redundancy would be 2 one of the tools that you would h ave to meet your 3 reliability r equirements.
So after you s et your 4 reliability requirements redundancy may be n ecessary, 5 it may not be, on a case-by-case basis.
6 MEMBER MARCH-LEUBA:
S o your guidance does 7 not have s ingle failure c riteria, yes. It's a 8 guidance.9 MR. FLEMING: N ot as an arbitrary 10 requirement.
11 M R. REDD: How we would address that i s 12 again point out that through the PRA process y ou look 13 at all forms and f ailure combinations including 14 combinations that are extraordinarily unlikely so you 15 get that same value of looking a t a single l i m i t ing 16 failure t hrough a much more systematic and 17 comprehensive evaluation through the PRA process. 18 Karl, is that a fair statement?
19 MR. FLEMING: That's a fair statement.
20 ACTING CHAIRMAN CORRADINI:
But to g et to 21 Jose's point, if it b ecomes a D BA I still would use a 22 single failure criteria.
23 MR. REDD: No.
24 ACTING CHAIRMAN CORRADINI: No.
25 MR. REDD: No, we do not --
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 141 1 ACTING CHAIRMAN CORRADINI:
Your point is 2-- then your point r eally is that the design when 3 going thro u g h this exercise you'll s ee diversity or 4 redundancy b eyond safety-related equipment.
That's 5 when you said it was -- you called it single failure 6 heavy.7 MR. FLEMING: H eavy. Y es. In that 8 respect, yes.
9 ACTING CHAIRMAN CORRADINI: So let me do 10 a process question. We're at noon. A natural break 11 point a t l east if I see it in the slides is a fter 12 slide 15. Where would you want t o break? That's what 13 I guess I wanted to ask you.
14 MR. FLEMING: I t hink if you give m e five 15 minutes and then we'll get to a logical break point.
16 ACTING CHAIRMAN C ORRADINI:
Okay, t hank 17 you.18 MR. FLEMING: At the J u n e meeting Joy 19 brought up a question about safety ma r g i ns which we 20 didn't have a chance to really give a good answer for 21 so we prepared this slide specifically for you, Joy.
22 This is summarized in t he guidance 23 document.
There's a half a page or so text that 24 basically wraps around this.
25 But there's -- the approach to safety NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 142 1 margins in the LMP framework there's a plant-l evel 2 safety margins and those are reflected i n the margins 3 between where the frequency consequence points plot 4 against the frequency consequence target.
5 And as we got feedback from the staff in 6 an earlier version of our paper by making this 7 compariso n o f where our points plot relative to 8 frequency consequence target it's one way to 9 demonstrate enhanced safety margins consistent with 10 the Commission's Advanced Reactor Policy Statement.
11 Then we also have S SC level safety margins 12 and those are set in both t he reliability targets that 13 we set as w ell as the performance targets we s et by 14 selecting design codes in order to be able to perform 15 the safety functions with adequate assurance.
16 So we have both the plant-level and SSC-17 level s afety margins and we confirm the a d e quacy of 18 these margins as an important element of t he defense-19 in-depth process.
20 If we can go on to the n ext s lide, please, 21 unless there's a -- did that answer your question, 22 Joy?23 MEMBER REMPE: M aybe I missed it but does 24 it talk about how the d efense-in-depth process will do 25 this? I know that there's programmatic and plant-NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 143 1 level defense-in-depth and different things like t hat, 2 but does it really -- is it going to be something 3 where y ou kind of have to feel it out with another 4 demo and have this integrated decision panel look at 5 this to really understand how it's going to work?
6 MR. FLEMING: I think that will probably 7 help. T he i ntegrated decision-making process -- w ell, 8 the integrated decision-making process on defense-in-9 depth will measure these m argins up in the p lant 10 level. 11 They'll say, okay, you p ut together a 12 table. There's ex a m ple tables in the guidance 13 document that show how far away -- what a re your o rder 14 of magnitude m a r gins in both the frequency and 15 consequence scale for all y our design b asis -- I'm 16 sorry, all your LBEs.
17 You do that p rocess and that's an input to 18 say based on a frequency consequenc e w hat kind of 19 margin do you have in that. So they do that.
20 And then in t he S SC s afety margin area the 21 IDP process is actually taking a lead role in setting 22 what the reliability requirements are g oing t o be and 23 what t he p erformance requirements are going t o b e for 24 all t he special treatment.
So they have a big 25 influence on what comes out of the special treatment NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 144 1 box in the process.
2 MEMBER REMPE: When you said the IDP you 3 mean the panel will help s pecify this, or do y ou mean 4 just the process?
5 MR. FLEMING: The process.
6 MEMBER REMPE: The process. A nd t he p anel 7 will review it.
8 MR. FLEMING: We like to emphasize the 9 integrated decision process. T here's a panel exercise 10 here but it doesn't do all this work. There's a lot 11 of integrated decision pro cess t hat goes along the 12 way. 13 That's one thing we tried t o clarify in 14 the last version of our guidance document is that it 15 initially appeared a s that all this importa n t s tuff 16 was going to be done when w e convened t his panel at 17 the end of the p r o c e s s and that was a m isleading 18 picture.19 MEMBER REMPE: I guess I sti l l had that 20 concept. In the MHTGR and NGNP h as this process been 21 fully exercised yet?
22 MR. FLEMING: No. Well, in the MHTGR it 23 was embedded, implied in their process but they didn't 24 call it t hat. But i f y ou go a s k F r e d Silady and 25 others how they actually p ut together their design it NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 145 1 actually -- it was a joint interaction b etween the 2 design team, the PRA team, the a nalys i s t e am. They 3 all got together and made decisions.
4 MEMBER REMPE: -- part of that process and 5 we used to have a transient plant design. But the way 6 the NEI --
7 MR. FLEMING: So it wa s e mbedded in the 8 MHTGR. But if you look at the documents IDP doesn't 9 appear in the documents.
They didn't make a b ig deal 10 about it. It was just the natural way to do it.
11 MEMBER REMPE: I n t his N EI document it 12 implies it's more form a l i zed, and I d on't recall it 13 being that formalized back in the MHTGR days.
14 MR. FLEMING: Well, we tried to put more 15 structure in this process.
16 MEMBER REMPE: Did the NGNP have t his more 17 structured process implemented?
18 MR. FLEMING: Well, in the N GNP we didn't 19 really do much to apply this to a design.
20 MEMBER REMPE: I t's n ot really been 21 exercised is where I'm kind of going, a nd I t hink 22 maybe it may need to be that way more.
23 MR. FLEMING: The one part that has been 24 exercised and we'll tell you about this afternoon is 25 in the G E PRISM tabletop t hey took a cut at looking at NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 146 1 their non-safety-related with special treatment SSCs 2 that are necessary for defense-in-depth.
3 Now, they didn't get into special 4 treatments and performance requirements yet, but 5 putting components into the NSRST box was -- we have 6 an example o f that for PRISM and we'll show you the 7 results after lunch.
8 MEMBER REMPE: Thank you.
9 MR. FLEMING: I think given where we are 10 it's probably a good time to stop for lunch.
11 ACTING CHAIRMAN CORRADINI:
So we'll pick 12 it up with the penultimate diagram.
13 (W h e r e upon, the above-e n t i t l e d m a t t e r w e n t 14 off the record at 12:08 p.m. and r esumed at 1:14 p.m.)15 ACTING CHAIRMAN CORRADINI:
Okay, why 16 don't we begin. Karl, you stopped on slide 13. You 17 wanted to move on to the most important.
18 MR. F LEMING: Before I m ake a key point on 19 this slide I wanted to r evise a nd extend my remarks on 20 a couple of items that came up before lunch.
21 With the question of our experience in 22 handlin g t he scope of different hazards through the 23 LMP process I forgot to mention in the M S R E w ork 24 that's ongoing and Steve Kra h n w i ll talk to in a 25 little bit t hey are looking a t t h e offgas system in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 147 1 addition to the fuel cell system. So we are in fact 2 getting some experience outside the normal core thing.3 The second point I wanted to make refers 4 back to discussion we had on uncertainty and it also 5 refers to a request that Dennis made that we identify 6 things that have changed in the guidance document.
7 We added a paragraph in the guidance 8 document, I can guide you to the specifics i f I can 9 remember it. I can't, but we can get that to you.
10 But we wanted to make an emphasis on the 11 point that the LMP process is designed to be flexible.
12 It c an be introduced early in t he process and we o ffer 13-- we identify some advantages to doing that.
14 Or you can a lso apply it late in the 15 process in more of a confirmatory m ode. The G E P RISM 16 example that we went through is maybe one example of 17 a d e s i g n that w as designed using more traditional 18 approaches and then the process came about later.
19 Kairos is planning to do a demonstration 20 project on their f luoride high temperature salt 21 reacto r. And in their case they're going to r isk-22 inform qualitatively t heir safety design approach with 23 a view towards using L MP to c onfirm the s elections 24 that they made rather than to develop them.
25 So the reason I'm bringing this paragraph NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 148 1 up is t hat when we talked about the question a b o ut 2 uncertainties I wanted to point o ut t hat this question 3 about uncertainties is n ot a property of t he LMP 4 process. It's not a property of even trying to do a 5 PRA. It's the property of our state of knowledge 6 about the machine we're trying to license.
7 And I just wanted to point out that we can 8 see advantages to early introduction of this process 9 we believe will help flesh o ut what the uncertainties 10 are earlier in the process and hopefully m inimize the 11 chance that you end up with costly backfits. That's 12 just a value judgment that I wanted to make.
13 On the current slide, the frequency 14 consequence c hart, this w as a ctually a lluded to in the 15 earlier morning discussion.
We've adopted a s et of 16 risk significance criteria for l icensing basis events 17 and we're setting those at 1 percent of the frequency 18 all the way down the frequency consequence target.
19 If any part of your uncertainty bands on 20 both the dose and the frequency get inside this zone 21 then we c onsider it a risk-signif i c a nt LBE and of 22 course we look at that m uch more c a r efully than we 23 would look at other LBEs that a re not in that process.24 So the discussion we had this m orning and 25 the concerns a bout the selection of t he 750 r em number NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 149 1 which anchors the lowest point i n the BDBE region down 2 there, this is something that was car r i e d over from 3 the NGNP process.
4 A n d I wanted to p oint out this is a 5 surrogate.
This i s a d ose surrogate, d ose to be 6 calculated at a fixed p oint at the plume center l ine. 7 This is a surrogate for verifying that 8 you've met the QHOs. The QHOs for e arly fatalities is 9 the average i ndividual r isk in a doughnut-shaped h ole, 10 a doughnut-shaped area from the site boundary to one 11 mile beyond the site b oundary for early health 12 effects.13 If the doses at the p lume center line, at 14 the EAB happen to be 750 r em t he average doses in the 15 doughnut hole are well below the threshold for early 16 health effects.
17 S o t here was actually some work done to 18 demonstrate
-- this is a ctually a conservative 19 selection, but it's j u st a surrogate for a more 20 elaborate individual risk calculation away from the 21 site boundary.
22 Because as the doses get one mile beyond 23 the site bou ndary the dose versus distance profile 24 will dilute t he dose quite a bit. Just wanted to make 25 that point.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 150 1 MEMBER SKILLMAN:
K arl, f or those hatched 2 areas where you express the caution in the 1 percent 3 zo ne i s there sufficient guidance to prevent t here 4 from being the kind of tortuous discussion that we 5 might have with an item that's more than minor, if you 6 will a gray definition o f w hat it means t o be only 7 slightly more than risk-significant b ut not to the 8 limit and t h e refore you burn u p h undreds o f h ours 9 barking and arguing over trivia.
10 Is the dotted line sufficiently i dentified 11 or codified that the d esigners would know once you 12 cross that line you need to consider more action?
13 MR. FLEMING: First of all, i t's very 14 important to emphasize that this is a statement of 15 risk significance.
If you look at any PRA result from 16 a l ight water reactor you'll see the identification of 17 risk-significant event s equences or accident 18 sequences, risk-significant basic events and so forth.19 This is the tool that we would use based 20 on a bsolute metrics t o s ay what is a significant risk 21 as far as an LBE is concerned.
22 It just means it's significant.
It 23 doesn't mean it's not acceptabl e. However, w hen we 24 get events that start to encroach i nto that zone 25 they're going to get m uch m ore f ocused in the defense-NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 151 1 in-depth evaluation.
2 So the d efense-in-depth evaluation, the 3 in tegrated decision process u sed there is going to 4 look very carefully at the results coming out of the 5 PRA, the limitations of the PRA, t he screening 6 criteria and so forth.
7 And when you're getting into these risk-8 significant L BEs they're goi n g to drill down and 9 understand what's behind that calculation. First of 10 all, the definition of the LBE in terms of the event 11 sequence families and also t he estimatio n of the 12 frequency and consequence.
13 So the trigger p oint is not a t r i gger 14 point of unacceptability, it's more of a trigger p oint 15 for focusing the resources of the defense-in-depth 16 evaluation. Hope that answers your question.
17 M E M B ER SKILLMAN:
It does, b ut to me it 18 raises the issue that we've a ll dealt w ith and that is 19 once you set a line or a limit for better o r for w orse 20 it becomes a d i scussion i tem. And depending o n the 21 strength of the personalities depends on h ow m uch more 22 resource you're g oing to expand to determine how much 23 further you're going to go.
24 MR. FLEMING: Right.
25 MEMBER SKILLMAN:
So unless that NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 152 1 definition is very, very clear that it is a guide and 2 not a drop dead consideration then what you have 3 stated seems to make sense.
4 But having dealt with this kind of thing 5 my w hole life I know sure a s s hooting someone's g oing 6 to say we crossed t he line. It's obviously got to be 7 in that bin, n o t t h a t b in, so it n eeds more QA, it 8 needs more of this, more o f that, more analysis.
And 9 t h e o nly w ay you can undo t hat is to m ake sure that 10 it's v ery clear that that line is not a drop dead 11 go/no-go gauge.
12 It's a trigger for greater consideration, 13 but it's not in itself a limit.
14 MR. FLEMING: That's rig h t. It's very 15 important to note that.
16 And also the fact that it's -- these are 17 absolute definitions, i.e., there's a fixed frequency 18 consequence curve and a fixed 1 percent line b elow 19 that as opposed to looking a t significance relative to 20 the baseline result which is the way light w ater 21 reactors do risk significance.
22 So, there's always something significant 23 in a light water reactor PRA b ecause it's j u s t a 24 relative metric. So we w ould expect in most o f the 25 case studies we've seen we h a v e n't really seen very NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 153 1 many examples at all of any LBEs show up in this 2 region, but it's certainly possible.
3 MEMBER SKILLMAN: Thank you, Karl.
4 MR. FLEMING: If we can go on to t he next 5 slide. This last of the p rocess s lides. The defense-6 in-depth evaluation.
We've a lready talked quite a bit 7 abou t t h at so I didn't plan on doing a soup to nuts 8 discussion on that.
9 In t he guidance document we break down 10 attributes of defense-in-depth for each of the three 11 yellow cornerstones up h ere, the plant c apability 12 defense-in-depth, the programmatic defense-in-depth 13 and the evaluation of risk-informed performance-based 14 evaluation of adequacy.
15 And so t hose a t t r ibutes a re u sed by the 16 integrated decision process and the panel to come up 17 with a baseline defense-in-depth evaluation which is 18 documented and then provid e s a basis f or change 19 management as the design goes through various stages 20 of development, licensing and siting and so forth.
21 So I t h ink we've t alked about most of 22 these. I didn't want to spend too much more time on 23 this. This is I think one o f the cornerstones of 24 advancing the technology-inclusive approach that came 25 out of the NGNP project.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 154 1 There was a defense-in-depth white paper 2 for NGNP t hat is consistent with this b ut I t hink 3 we've taken -- in sort of a football analogy w e t hink 4 we've advanced the ball down t he field o n this topic.5 MEMBER REMPE: So out of curiosity I was 6 trying to think of this when I was r eading the 7 material.
Is there an emphasis to make sure y ou have 8 some plant capability as well as programmatic 9 capability defense-in-depth.
You s hould draw from 10 both types of options. Plant capability is t he device 11 basically and you do have to have --
12 MR. FLEMING: Well, yes. They're s ort of 13 like different kind of a nimals. One way to look at 14 plant capability defense-in-depth i s defense-in-depth 15 on paper. So if I build this plant according to the 16 way i t was designed and I i mplement the safety design 17 approach and the r e's no c hanges and whatever, no 18 uncertainties, then it's sort of like an as designed 19 sort of defense-in-depth.
20 W h a t t h e programmatic d e f e n s e-i n-d e p t h , i t 21 does t wo things. Number one i s that it p uts in 22 processes to m ake sure that if y ou build i t according 23 to the d esign it will b e maintained a nd operated 24 through the l ife of t he plant maintained i n that 25 design envelope.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 155 1 And also to address uncertainties in all 2 the decisions that went into putting the features into 3 the plant capability defense-in-depth including things 4 like what do we have to do to assure the reliability 5 and c apability of the SSCs t hat are part of my 6 defense-in-depth, the uncertainties that may have come 7 out of the frequency consequence evaluation in 8 evaluating LBEs.
9 So i t's more of a preservation of defense-10 in-depth through all phases of building the plant and 11 operating it, licensing it and managing uncertainties 12 and deviations, temporal deviations in performance.
13 MEMBER REMPE: S o your response implies to 14 me you have to have --
15 MR. FLEMING: You have to have both.
16 MEMBER REMPE: Thanks.
17 M R. REDD: Let's ask Ed W allace c an you 18 comment briefly on the balance about whether we have 19 to have -- Dr. Rempe I think your question is do you 20 have to h ave balance or does t he guidance tell you to 21 balance programmatic and --
22 MEMBER REMPE: I just was exploring it.
23 MR. WALLACE: A c ouple of thoughts here to 24 add to Karl. One is when you look at this equation of 25 sorts these are contributions to reasonable assurance NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 156 1 and adequate protection.
2 And so adequate p rotection is m ore aligned 3 with how does the plant p erform and r e asonable 4 assurance is h ow confident a re you about how does the 5 plant perform.
6 And so the programmatic activities start 7 to go to things like tech specs. As long as y ou stay 8 in the operating box that the d esign was b u i lt for 9 then there's a higher likelihood that you're n ot g oing 10 to run into a problem.
11 As long a s you monitor the systems to make 12 sure they're not degrading in service then there's a 13 higher likelihood
-- that's a special t reatment.
14 Higher likelih o o d that you're not going to get 15 surprised later in life.
16 So ther e's a series of things. Y ou can 17 include QA. Karl mentioned earlier a nd I t h i n k Dr.18 Corradini also made a p oint about early in the design 19 your sources of uncertainty are e xtremely important 20 when you l o o k at what's g oing on. T here's a lot of 21 unverified assumptions in the design p rocess that get 22 worked through.
23 And o n e of the answers when you d o this 24 may be gee, this phenomena we don't know enough a bout 25 and it's driving the uncertainty bands around the mean NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 157 1 which might t i c k l e if you w ill to the question that 2 Dick asked the cross hatch zone. We'd say w hy is that 3 happening.
4 And so the p urpose of the defense-in-depth 5 process i s systematical l y to s ay we ought to be 6 look i ng at t hat harder in a different s tructured 7 manner and we ought to be looking at is it driven by 8 plant capability, is there compensatory measures that 9 you could take that w ould be more programmatic but not 10 c hange the plant capability one of which is g o r u n 11 s o me more t ests in your integrated non-nuclear te s t 12 facility i f you have one s o that you can sharpen your 13 pencil to use the term t hat was u s ed earlier a bout 14 that uncertainty and its significance to your overall 15 plant performance.
16 So you end up with a set of t hings in both 17 camps and the design process sort of weighs the best 18 way to solve the problem and part of the defense-in-19 depth description is if it's already in concrete your 20 design options are limited a nd so y ou may have a bias 21 towards trying to solve the problem programmatically 22 because t earing out concrete is not a g ood idea if you 23 can avoid it.
24 MR. REDD: Thank you, Ed. K arl, w hich 25 slide.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 158 1 MR. FLEMING: Let's go to the n ext slide, 2 please. Now t he balance of our presentation is g oing 3 to focus o n l essons we're learning by applying this 4 process to different technologies.
And they're 5 summarized here on one s lide, everything t hat has been 6 done or is planning to be done by the spring of 2019 7 to support the processes in the LMP.
8 And I put them in to sort of accident --
9 reactor type fam i lies. T he high temperature gas 10 cooled reactors, the liquid metal cooled reactors, the 11 molten salt r eactors and t hen we have some o ther 12 reactor concepts that have different combinations of 13 fuel coolant type arrangements.
14 ACTING CHAIRMAN CORRADINI: So these are 15 like pilot applications of the LMP?
16 MR. FLE M I N G: Well, yes. Each of t hese 17 contributes to some element of e xperience i n applying 18 the LMP process. I'm going to s how you a matrix 19 coming u p that bre a k s it down into which reactors 20 apply t o which steps of the process to give you an 21 idea of where we are today.
22 ACTING CHAIRMAN CORRADINI:
But none of 23 the four if you want pilots have exercised the whole 24 process.25 MR. FLEMING: That's correct.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 159 1 ACTING CHAIRMAN CORRADINI:
Is the intent 2 that they will eventually?
3 MR. FLE M I N G: That's -- I d oubt whether 4 every a spect of the process will b e d emonstrated in 5 the pilots. There's just too much resources.
6 ACTING CHAIRMAN CORRADINI:
The reason I'm 7 going there is to the extent that the industry works 8 together and understands it t ogether t he b etter off it 9 is downstream versus a fragmentary understanding.
10 So t h e thought that you're running -- I 11 keep on using the word pilots. The fact that you're 12 running four of these strikes me as interesting. It 13 would be more in t eresting if they completed them 14 because then any other p articular vendor i n a 15 particular type can l ook back and see an empirical 16 example of how --
17 MR. FLEMING: Right.
18 MR. REDD: And I want to add that as w e've 19 progressed through these demonstrations that the 20 amount of detail we've b een able to go into and the 21 further t hrough t he p rocess we've been able to go has 22 been b eneficial.
Especially one site, the G E-Hitachi 23 P R I SM exercise given t hat they're by far the mos t 24 complete d esign. We were able to exercise a g ood bit 25 of the process there that we'll discuss further on.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 160 1 MR. FLEMING: And when I get to the next 2 slide, Michael, I think I can g et a more complete 3 answer to your question.
4 In the high temperature gas cooled reactor 5 family this process was really first started with the 6 MHTGR licensability submittal t h a t was done back in 7 the nineteen eighties.
8 That w as done in conjunction with a 9 preliminary safety information document, a P RA, an NRC 10 staff and N RC staff contractor r evi e w. This is 11 probably the most complete application of the process 12 although some steps of t he p rocess were i nvented a fter 13 MHTGR so they weren't able to do it all.
14 ANS 53.1 and Jim August mentioned that he 15 was the c hairman of that group that put t ogether that 16 standard, that built upon the methodology in between 17 the Exelon P BMR interaction a nd the NGNP p r oject is 18 when ANS 53.1 came along.
19 And it basically d ocuments a design 20 process that follows the basic elements of the LMP 21 framework.
22 We recently completed and Brian Waites 23 reported thi s morning we completed a limited s cope 24 demonstration on the XE-100 pebble bed r eactor and we 25 have a public domain report that documents that. I'm NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 161 1 going to show s o m e e xample results that we got from 2 that.3 In the liquid metal -- i n th e sodium 4 cooled fast reactor family GE PRISM similar to MHTGR 5 submitted a l icensability submittal, a preliminary 6 safety information document, a PRA, NRC sta f f a nd 7 contractor review and published NUREG-1368.
8 GE-Hitachi has also been actively involved 9 in supporting with m any other advanced reactor 10 developers in developing a non-light water reactor PRA 11 standard.12 We i ssued a trial use standard in December 13 of 2013 a nd it was intended to be piloted by a number 14 of projects.
There were quite a f ew different 15 projects that piloted i ncluding the Chinese HTRPM that 16 was used to license t he pebble bed reactor b eing 17 designed and just about ready to start up in China.
18 And one of t he things that transpired was 19 the Department o f E n e rgy g ranted a project to GE-20 Hitachi to modernize their PRA specifically to pilot 21 the non-light water reactor PRA s t a n d ard and give 22 feedback to the standard process.
23 And t h a t gave the opportunity to have a 24 very modern PRA project that was done that supported 25 a demonstration project, the t abletop project that NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 162 1 we're going to talk about here in a few minutes.
2 In t he molten salt reactor area there's an 3 activity underway that Steve Krahn will tell you more 4 about in a few minutes involving using the molten salt 5 reactor exp e r i ment as a design and a plant that's 6 already operated and had some s e r v ice e xperience to 7 work t h rough the process to support t he molten salt 8 family reactors using the LMP process.
9 And they've already published a report 10 where they've started to t a ke a l ook at licensing 11 basis events for the M SRE u s i n g the LMP process 12 starting from basically a blank sheet of paper.
13 And they're also a dvancing the t echnology 14 of using HAZOPs, p rocess hazards analyses like HAZOPs 15 and failure modes, effects a nalysis to b u ild the 16 knowledge b ase that you would need to start this 17 process. And Steve will amplify on that i n a few 18 minutes.19 We also have planned s ome demonstration 20 projects, some pilot projects on the Kairos fluoride 21 salt reactor and a lso the Westinghouse micro reactor, 22 the eVinci heat pipe reactor. And both of those are 23 planned demonstrations to be completed by the spring 24 of 2019.25 So now I'd like to go on to t he next s lide NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 163 1 and s tart getting into what they actually d id. So in 2 this matrix we've identified this is progress to d ate. 3 So this is actually what's been completed to date.
4 It doesn't credit what we plan to do for 5 the ones that haven't been finished yet.
6 So t his matrix shows it's broken d own. 7 Ther e's about 18 different steps of t he LMP process 8 and we tried to capture here some of the key s teps of 9 the process including developing an internal events 10 PRA, a seismic PRA, a PRA that covers both single and 11 multi-module sequences enough to define the AOOs, DBEs 12 and BDBEs using the ac c i d ent f amilies coming out of 13 those studies, evaluate the LBEs against the frequency 14 consequence t arget and the cumulative risk targets, 15 identify the required s afety functions that are 16 necessary and suffic i e n t to keep our design b asis 17 events inside the target, and have at le a s t example 18 selections of safety-related SSCs that would perform 19 those functions.
20 We also have the process step of 21 developing functional design criteria for the safety-22 related SSCs and safety-related design conditions.
23 That's SSC-l evel design criteria.
Those two s teps 24 have only been performed for the MHTGR.
25 This actually involves a completed design. NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 164 1 It's difficult to tabletop some of these steps.
2 And we also have looking into t he defense-3 in-depth s t e p s we've broken down two parts to t hat. 4 That's evaluating the plant capability for defense-in-5 depth and we h ave some limited e xperience with the GE 6 tabletop on that.
7 And also the r est of the defense-in-depth 8 process including the programmatic defense-in-depth 9 and the application of t he i ntegrated decision 10 process. So this is the matrix that shows you where 11 we are today.
12 CHAIRMAN BLEY: This is Denn i s. Two 13 things I wanted to ask you about. O n a l l of t hese 14 cases you were able to compare t he LBEs with t he FC 15 curves which implies you were able to develop source 16 terms for all of these scenarios.
Are t hose described 17 in something we can look at, how that was done?
18 MR. FLEMING: We'll get into t he e xtent of 19 source t erm develo p m e nt. The examples we have up 20 here, the MHTGR and the GE PRISM a re supported by 21 mechanistic source term analyses to develop the doses. 22 T he XE-100 based on i ts s tage of design we ju s t 23 p r o v ided estimates of those based on scaling fro m 24 power level based on results of other studies.
25 And the molten salt reactor e xperiment NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 165 1 I'll let Steve tell us what they plan to do for source 2 terms on that.
3 ACTING CHAIRMAN CORRADINI:
So let m e just 4 make sure I understand what N/A means.
5 MR. FLEMING: N/A m eans it w asn't -- that 6 step wasn't available when the M H T G R was done. The 7 MHTGR was done i n like 1988 and we hadn't invented 8 these DID steps. We hadn't invented that.
9 ACTING CHAIRMAN CORRADINI:
E xcuse me. So 10 NGNP is not a potential pilot. This is the 1986 11 MHTGR.12 MR. FLEMING: The NGNP really didn't 13 involve a pilot. There were several different designs 14 but it wasn't really a n actual demonstration like was 15 done for the MHTGR.
16 CHAIRMAN BLEY: They hadn't actually 17 settled on their design.
18 ACTING CHAIRMAN CORRADINI: Dennis, it's 19 hard to understand you. C an you say it a little 20 louder, please?
21 CHAIRMAN B LEY: I said NGNP didn't 22 actually -- had not actually settled on a design.
23 MR. FLEMING: That's right.
24 ACTING CHAIRMAN CORRADINI: I think they 25 didn't s ettle o n their reactor core design, but I NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 166 1 thought most of the e quipment between the t wo designs 2 were similar outside of the core geometry.
3 I think we have -- I'm looking at -- w here 4 did he go. I'm going to drag Jim u p t o t he mike to 5 make him properly characterize this.
6 MR. KINSEY: W e had s ome preliminary 7 information from the three players who were involved 8 with pursuing designs but there was no selection and 9 it didn't g et -- those designs didn't progress far 10 enough in their level of detail to be a ble to a pply 11 the process.
12 We used the GA MHTGR design as sort of our 13 surrogate f or all of those d iscussions d uring NGNP as 14 our poster child.
15 ACTING CHAIRMAN CORRADINI:
So the reason 16 I asked the question --
17 CHAIRMAN BLEY: -- my memory.
18 ACTING CHAIRMAN C ORRADINI:
I'm sorry, 19 Dennis, go ahead. I apologize.
20 CHAIRMAN BLEY: I said what Jim said 21 agrees with my memory.
22 ACTING CHAIRMAN CORRADINI:
Okay. But 23 since J im is there can I m ake sure I'm c lear? In the 24 MHTG R a n a lysis they didn't do the ones that are N/A 25 but in terms of functional -- I'm still back to what NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 167 1 we've already written about and what we have taken a 2 position on in terms of functional containment.
3 These a re particularly o f interest to me. 4 So I'm kind of curious in terms of d e fense-in-depth 5 adequacy is the only example this has been exercised 6 is with the PRISM?
7 MR. FLEMING: So far, yes.
8 ACTING CHAIRMAN C ORRADINI:
Okay, t hank 9 you.10 MR. FLEMING: That's where we are.
11 MEMBER DIMITRIJEVIC:
Okay, so my 12 question, you show us t he graph with t he -- the r isk-13 significant, the safety-significant.
That was only 14 done on PRISM as much a s I can see, r ight? Is it 15 done? Because I'm n ot sure that these, l i k e for 16 example the necessary required s afety function that's 17 where w e can identify systems which will g e t safety 18 classification.
19 And then I can s ee the risk was done, the 20 significance was done a nd if defense-in-depth was done 21 then y ou h ave a safety significance there t oo, right?22 MR. FLEMING: That's right.
23 MEMBER DIMITRIJEVIC:
So will y ou show us 24 example how many SSCs we have --
25 MR. FLEMING: For PRISM.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 168 1 MEMBER DIMITRIJEVIC: You have that.
2 MR. FLEMING: For PRISM. We'll have t hat. 3 It's on one of the slides.
4 MEMBER DIMITRIJEVIC:
Okay, a ll right. 5 Excellent.
6 MR. FLEMING: Okay. Shall we move on to 7 the next s l i de? Some general points that w e've 8 learned collectively and many o f these les sons are 9 already reflected in draft November or whatever we 10 call it of the guidance document.
11 S o we now have experience with at lea s t 12 including some that a r e sort of s till a work in 13 process on the three major families of advanced non-14 light water r eactors meaning the high temperature gas, 15 the liquid metal and the molten salt reactors.
16 The feedback we've gotten from the 17 developers and I'm going to ask them to give us this 18 in their own words, but they found the demonstration 19 to be useful. They like the approach and it s eems to 20 produce re s u l ts that they t hink are r easonable.
So 21 that's the feedback we've gotten from them. And w e'll 22 get some more specifics on that from the developers in 23 a little bit.
24 They r eally liked the idea of u sing 25 absolute metrics for d etermining r isk significance.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 169 1 It r e a l l y focuses the statement of what's r isk-2 significant to what's really important.
3 If we h ad stuck with the relative 4 significance we might be -- we m ight have an 5 unnecessary burden.
6 And also I want to point out a n important 7 insight. This actually happened from the GE PRISM PRA 8 modernization that was done to pilot the n on-light 9 water reactor standard.
10 When we first wrote the risk significance 11 c r iteria in the non-light water reactor standard w e 12 used the light water reactor model. There was a lot 13 of pressure by the Joint Committee on Nuclear Risk 14 Management to keep e verything consistent with l ight 15 water reactors unless it had to be different.
16 So we used the risk significance criteria 17 where we mapped the requirements for CDF-b a s ed risk 18 significance to all the release categories.
19 And what GE PRISM found w a s i t just 20 created a mess because t hey had 40 r elease categories.
21 So t h e y had 40 sets of F ussell-Veselys and risk 22 achievement worth and so forth.
23 So i t w as actually f eedback f rom the GE 24 PRISM PRA modernization proj e c t that had a g reat 25 influence on how we do safety significance
-- risk NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 170 1 significance in the LMP. S o that's already b aked into 2 the guidance document.
3 And we're now w orking o n putting t hose 4 absolute risk metrics for risk significance into the 5 standard.
We're working on the next generation of 6 this standard now.
7 So that was a huge -- it h as a huge 8 impact.9 MEMBER SKILLMAN: Karl, by changing from 10 relative to absolute did the conclusions change?
11 MR. FLEMING: Oh, y es. The population of 12 risk-significant SSCs was --
13 MEMBER SKILLMAN: Night and day.
14 MR. FLEMING: Y es, night a nd day. 15 Absolutely. Huge, huge difference.
16 The oth e r thing w e l earned and a gain we 17 learned this, this was in the GE-Hitachi demonstration 18 project. The V e n n d iagram I showed you t hat showed 19 all the different safety-significant, r isk-20 significant, safety-related SSCs.
21 We u s e d to think t hat all the safety-22 related SSCs were risk-significant based on our 23 definition a nd we put that down there. A nd it was 24 actually the GE-Hitachi PRA people who had e xperience 25 with the ESBWR and had done a similar approach where NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 171 1 in their example they had 14 different w ays t o g et 2 water in the vessel a nd therefore whatever safety-3 related S SCs for vessel injection that they had in the 4 ESBWR that was not risk-significant because they had 5 14 backups.
6 So they clarified that Venn diagram for us 7 and got us a b etter understanding o f t he relationship 8 between risk-significant, safety-related and safety-9 significant. So that was a good insight.
10 MEMBER KIRCHNER:
J ust quickly going back 11 t o your Venn diagram. H ow d o you s quare that so t o 12 speak with the N RC's d efinitions for safety 13 classification and performance criteria?
W here you 14 have three, s afe t y-r e l a t e d , n o n-s a f e t y-r e lated special 15 treatment and non-safety-related with no special 16 treatment.
17 MR. FLEMING: Yes. For t h o s e t hree 18 categories
-- w e ll first of all, having those t hree 19 categories was s omething that actually was imported 20 from the N GNP process. The NGNP p rocess also had 21 those three safety classes.
22 But a s far as the current reactor is 23 concerned this is similar to the 50.69 process where 24 you're d ividing up a nd y ou're defining safety-25 significant sequences o ther than safety-related b ased NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 172 1 on risk significance and defense-in-depth.
2 So we think there's some alignment there 3 with the 50.69 j ust as far as the safety 4 classification process.
5 MR. REDD: And just t o emphasize w e're not 6 trying to implement the 50.69 p rocess here. It's just 7 a similar framework looking forward. That's one key 8 takeaway we want to be very clear on.
9 MEMBER KIRCHNER:
I'm j ust thinking in 10 terms of clarification and simplicity are we g oi ng 11 with three categories or four categories?
12 MR. FLEMING: We only have three.
13 MEMBER KIRCHNER:
M aybe I'm just confused 14 then.15 MR. FLEMING: Oh yes. Okay, that's right. 16 We do have four, that's right.
17 ACTING CHAIRMAN CORRADINI:
I was going to 18 say --19 MR. FLEMING: That's rig h t. There are 20 four. Yes, I'm sorry, I misspoke.
There are f our. 21 It's the ones outside. Thank you.
22 MEMBER KIRCHNER:
Is there some 23 qualitative understanding with the N RC about how t hese 24 definitions are going to be used?
25 I mean, where I'm going i s so you made the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 173 1 pitch in the beginning that the process requires the 2 applications too much extraneous so to s peak 3 information and such.
4 It would see m t o m e your Venn diagram 5 ought to be first order of b asis for cutting out a lot 6 of material that isn't important to risk, right?
7 I guess I'm missing something here.
8 MR. FLEMING: Should we go back t o the 9 Venn diagram?
10 MEMBER KIRCHNER:
Doesn't this provide you 11 a means for streamlining the application in terms of 12 content a nd such if y ou can demonstrate that there are 13 SSCs that are outside the envelo pe of contributing 14 significantly to risk or whatever terminology you're 15 going to use.
16 It seems to me that for consistency this 17 would be the rationale or basis for then eliminating 18 material or excess material from consideration in the 19 license application.
20 MR. FLEMING: We l l , I guess it's our 21 general view that application o f the LMP process vis-22 a-vis a conventional ad hoc process should lead to a 23 more streamlined safety analysis report. But we 24 have n't actually gone through chapter by chapter to 25 actually demonstrate that yet.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 174 1 MEMBER KIRCHNER: Thank you.
2 MEMBER R E MPE: Could you go back to s lide 3 17. In light of all the insights that you've gotten 4 from doing what you've done why not -- are you 5 confident you wouldn't get a lot more insights if you 6 go t hrough and finish the rest of these s teps with the 7 PRISM design?
8 Again, I'm still h ung up o n how this w hole 9 defense-in-depth and integrated d ecision p anel is 10 going to work. I know you've said we don't have the 11 resources.
Depa r t m ent of Energy has a lot of 12 resources.
13 I'm just wondering is there something 14 important you would g lean i f you w ent another step 15 further and did some additional work in this area?
16 MR. FLEMING: I'm sure that we could g lean 17 more insights if we did more but really that question 18 is r eally something that needs to b e c o l lectively 19 asked to the developing community.
20 All of these developers are volunteering 21 their services to come and a pply this process because 22 they're excited about using it and they're investing 23 their resources to do it.
24 ACTING CHAIRMAN CORRADINI:
But I t hink 25 what Joy is asking i s another way of what I was saying NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 175 1 also which is th e i d e a that you guys have gotten 2 together and have again I use the word pilot t hese 3 four different approaches, or four different classes 4 and running through it. To the extent that you can 5 more completely do it I think it would be better for 6 the community.
7 It will clarify a whole lot of things it 8 strikes me.
9 MEMBER REMPE: Yes, especially s ince 10 you've spent extra time n o w to define defense-in-11 depth. T hat's what I'm thinking of and t he i ntegrated 12 whatever, decision panel and all that.
13 I just think that there's some fuzziness 14 in my mind from what I'm reading and maybe it's c lear 15 to you. But it seems like if you would step through 16 those additional steps you might learn some important 17 nuggets that ought to be considered. It's something 18 to think about. That's kind of where I'm going.
19 MR. REDD: Certainly.
We th a n k y ou for 20 the feedback. And a gain we've got several more 21 demonstration opportunities coming up.
22 MEMBER REMPE: But those designs are less 23 mature and I think you're g oing to have to use one of 24 the more mature designs to get that useful feedback.
25 Unless somebody really jumps their design ahead in a NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 176 1 hurry.2 MR. REDD: Certainly. Thank you.
3 MR. FLEMING: Any e xperi e nce we get we 4 should be able to benefit from. I certainly wouldn't 5 disagree with that at all.
6 If we can go on to that next slide. The 7 next to last bullet --
8 MR. AFZALI: S orry. T wo of our exercises 9 fundamentally the approach and t he methodology hasn't 10 chan g ed. The i nsight we've gained, we're mostly 11 focused on ease of application. So we have provided 12 additional clarity but t he fundamental approach hasn't 13 changed.14 So w e t o tally agree w i th the concept of 15 more applications to further improve the process and 16 execution part o f it. But fundamental part of our 17 process we have a pretty much confidence t hat it 18 works. It gives reasonable results. Just wanted to 19 clarify that point.
20 And Karl, I would like y o u to make sure 21 I'm no t misstating our findings as a result of our 22 pilots.23 MR. FLEMING: Yes, that's a very important 24 point. We're not finding th e n e e d to modify the 25 methodology from these t abletops but we are providing NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 177 1-- we're getting opportunities to provide better 2 guidance on h o w t o m ost efficiently implement it. 3 That's what we're basically getting out of it.
4 MEMBER R EMPE: Has the regulator been 5 involved with these demonstrations at all? Or is it 6 just the industry coming in and working with NEI?
7 MR. FLEMING: NRC staff sat in on o ne day 8 of the GE P RISM demonstration.
The GE P RISM 9 demonstration went over a period of s everal months and 10 there were lots of interactions and meetings between 11 the LMP t eam a nd the GE-Hitachi team that was working 12 on that.13 But the f inal day of sort of like 14 presenting the results the NRC staff participated in 15 a one-day meeting.
16 MEMBER REMPE: Were some additional a reas 17 for clarification was needed i dentified because of 18 that interactions with the regulator?
19 MR. FLEMING: I don't recall.
20 MR. REDD: Bill o r John S egala if y ou all 21 would like to provide any input.
22 MEMBER REMPE: No, okay. Thank you.
23 MR. FLEMING: The next to l ast point I 24 wanted to emphasize i s that one t hing that's c ome out 25 in our demonstrations is the i m portance of thinking NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 178 1 through all steps of the process before m a king 2 decisions. In other words if you're looking at your 3 frequency consequence charts a nd you're starting to 4 think about incorporating r isk insights before you 5 start thinking a b out making a change to anything 6 because you don't like the results work your way all 7 the w ay t hrough the process so you know all the t ools 8 that are available to affect the results i ncluding 9 what you're going to find out of defense-in-depth.
10 So this gets back to the fact that this is 11 an inte g r a ted process and it's not designed to be 12 taken piecemeal a nd applied partially from o ne aspect 13 of it.14 This really -- what Amir w as j umping up to 15 say was really the last bullet point on that is that 16 what we're f indi n g is we're finding w ays to improve 17 the guidance.
18 In f act, the GE and the X-Energy tabletops 19 that were already completed already are reflected in 20 changes in t h e guidance document.
So we're getting 21 better guidance out of it.
22 The next slide here is one slide we have 23 on the XE-100. This is a pebble bed reactor, a very 24 small pebble bed reactor. It's being designed by X-25 Energy. NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 179 1 And this is a good e x a m ple of what this 2 proc e s s w ould look like at a very early stage of 3 design. The conceptual design o f the X E-100 is 4 recently started. It started earlier this year. So 5 they're very, very early in their analysis.
6 And before the L MP project came along they 7 deci d e d to do a very, very high-level limited s cope 8 PRA just to help make some design decisions to support 9 some tradeoff studies o n h ow they were going to design 10 their core heat removal systems and also to get some 11 rough idea of what the licensing events were going to 12 look like that they need to w orry about i n the 13 conceptual design. And that was -- that PRA w as done 14 several years ago not necessarily tied to applying the 15 LMP process in general.
16 And it w a s a high-level PRA. The e vent 17 trees a nd event sequence diagrams from t h a t P RA are 18 actually in the PRA white paper t hat show examples of 19 h o w y ou can d evelop t he f irst building blocks of a 20 high-level PRA at an early stage of design.
21 But they knew what their sources of 22 radioactive material w ere, they had insights from 23 prior PBMR type PRAs. And what w e did in the tabletop 24 exercise was help the X E-100 folks develop r ough 25 estimates of what the doses would be because t heir NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 180 1 mechanistic source t erm analysis and t heir t ools 2 weren't ready yet to come up with their o wn e stimates.3 So we provided information from NGNP 4 studies and PBMR studies and MHTGR work and based on 5 power level scaling arguments they were able to come 6 up with rough estimates.
7 They actually do have i n the library of 8 work they a ctually do have u n c e rtainty estimates on 9 these frequency conseque n c es. But in the time 10 avai l a b l e it was hard to get them plotted on the 11 chart.12 MEMBER MARCH-LEUBA:
Karl, we h ave this 13 example here. I'm a very visual guy. We can go how 14 you select for this particular example the safety-15 related component.
Let me see i f I underst a n d w hat 16 you do.17 You will take the two green points which 18 are the AOOs a n d say those are going to be DBAs for 19 me. And identify --
20 MR. FLEMING: Let me w alk you through the 21 process. We start with the events in the DBE region.22 MEMBER MARCH-LEUBA: The other ones.
23 MR. F LEMING: Between 10-2 and 10-4 per 24 plant year. Now, when we d o that we capture events 25 whose uncertainties s traddle t he b oundary. So we make NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 181 1 the set as large as we can.
2 And then we analyze e ach LBE one a t a time 3 and we ask ourselves what safety functions were b eing 4 fulfilled that kept the doses as low as they are.
5 And by the way, a lso shown on here on the 6 y axis are LBEs that have no dose whatsoever.
There's 7 no dose at all.
8 So we look at those a nd a sk o urselves what 9 are the required safety functions that are needed to 10 keep those inside the frequency consequence chart.
11 And for this reactor the three they came 12 up with was controlled core heat removal, controlled 13 core heat generation or reactivity control and 14 controlled chemical attack.
15 And those in turn will assure the 16 containment of radionuclides.
17 MEMBER MARCH-LEUBA:
And then for your 18 chapter 15 you will run all those points with --
19 MR. FLEMING: Hold up, I'm n ot quite done 20 yet. So after we've done that we look at a ll the DBEs 21 that we started with and we identify which SSCs were 22 availab l e o r not available to support each of t hose 23 required safety functions.
24 So we g o DBE b y DBE. We look at every one 25 singly and then we say can we select -- what are our NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 182 1 options to select a single SSC t hat will p erform each 2 required safety f unction f or all t he DBEs, that c over 3 all the DBEs that's available in all the DBEs.
4 And normally there's options. For the 5 pebble bed reactor it turned out the options were the 6 reactor cavity cooling system or the heat sinks, the 7 passive heat sinks in the reactor building.
T hose 8 were the two options.
9 By the way, very similar r esult is mapped 10 o u t f o r the MHTGR in the L BE white paper. So th e n 11 they decide okay, which of those options do they want 12 to make safety-related.
13 And that's as far as we t ook that tabletop 14 exercise but that's the process.
15 MEMBER MARCH-LEUBA:
I didn't have any 16 problem with tha t. I w a n t to go b eyond ten to the 17 minus four. Now the beyond design basis event. You 18 said earlier that the highest one gives you 20 19 m i l l i r e m s so you say if you want more t han 2 and a 20 half rem you would consider it.
21 The beyond design basis events you a re not 22 going to evaluate what safety-related functions make 23 them safe?
24 MR. FLEMING: Well, by making t he safety-25 related s elections that we d id make base d o n NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 183 1 evaluating the D BE region it h e l p ed to reduce the 2 frequency of some of the BDBEs.
3 MEMBER MARCH-LEUBA:
F or those points that 4 you -- the purple points you put t here on that figure, 5 do they include all of the components, even the ones 6 that are not safety-related?
7 MR. FLEMING: Yes, it includes a l l of 8 them.9 MEMBER MAR C H-LEUBA: S o h ow d o y ou know 10 that t hose -- if you have fail a non safety g rade 11 component, you fail it, that will m ove to 2,000. How 12 do you know it doesn't?
13 MR. FLEMING: Well, we're g o i ng to pick 14 that up when we do the risk significance evaluation.
15 MEMBER MARCH-LEUBA: See, the thing that 16 makes sense t o me is you go through your red and g reen 17 points, decide what your s ystems are going to be 18 safety-relate d , fix t hem, rerun the BDBEs and t hose 19 components and none else. And then you know that 20 you're okay. But that's not what you're planning to 21 do.22 ACTING CHAIRMAN CORRADINI:
No, I t hink 23 you're one step ahead of what he said. Once I 24 identify -- I see it as a number of steps. The f irst 25 thing you identify your safety systems, safety-related NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 184 1 systems. The next step is you identify your r i s k-2 significant ones. Then with a defense-in-depth 3 ad equacy judgment which still I'm cloudy about you 4 might have an even larger p opu l a t i o n t han r isk-5 significant.
6 MR. FLEMING: That's right.
7 ACTING CHAIRMAN CORRADINI:
And then when 8 you want to d o a DBA analysis you b asicall y assume 9 everything that is not safety-related fails.
10 MEMBER MARCH-LEUBA: No, that's not --
11 MR. FLEMING: -- chapter 15.
12 MEMBER MARCH-LEUBA:
No, chapter 15 you 13 don't do BDBEs. You only do the DBEs.
14 (Simultaneous speaking.)
15 MEMBER MARCH-LEUBA:
I'm asking him to do 16 chapter 15 for all of them.
17 ACTING CHAIRMAN CORRADINI:
Why would you 18 do that? That doesn't make any sense.
19 MEMBER MARCH-LEUBA:
Let's take a 20 hypothetical.
I have an eve n t that melts my c ore, 21 breach es the vessel, but containment is intact and 22 nothing comes out. Is the containment a s afety g rade 23 or not? If you run the calculation and a ssume that 24 your containment failed that event kills a million 25 people. NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 185 1 But if you run it this w ay you say I d on't 2 need a containment, it's not safety grade.
3 MEMBER REMPE: W ell, doing the risk 4 assessment sometimes things m ay fail, some t hings may 5 not. But if you do a realistic analysis --
6 MEMBER MARCH-LEUBA:
Y our mike is not on.7 MEMBER R EMPE: But again i f you do a 8 realistic assessment for beyond design basis events 9 sometimes things will fail, sometimes t hings won't but 10 you consider that --
11 CHAIRMAN BLEY: Can't hear.
12 MEMBER REMPE: Sorry.
13 MR. FLEMING: When we determine our 14 required safety functions we're going to assess o kay, 15 if I didn't d o that function, like if I didn't have a 16 containment would the doses go o utside that line. And 17 if they do then that's assurance why we have to --
18 MEMBER MARCH-LEUBA: In all those events 19 I c an assure you t hat the containment at m osphere 20 remain inert m e a n ing air didn't come i nside the 21 containment otherwise we will have a fire.
22 And that's because there was a c omponent, 23 a window that remained closed and didn't b r eak. 24 Should that window be safety grade?
25 MR. FLEMING: That should show up in the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 186 1 required safety functions.
If that window is so 2 important it would be identified --
3 MEMBER MARCH-LEUBA: I can guarantee you 4 it is. I can guarantee you it is. If you flood the 5 contain m e n t with air and you h ave graphite that's a 6 bad scenario, really bad scenario. And you're going 7 to want to make that window safety grade. I can 8 guarantee you that too.
9 MR. FLEMING: Well, without getting into 10 the details t he phenomena of graphite oxidation is 11 tracked i n the evaluation of the high temperature 12 reactor LBE so graphite oxidation is tracked.
13 If you depressurize the helium pressure 14 boundary in the reactor building you will displace the 15 air from the building --
16 MEMBER MARCH-LEUBA: And then the window 17 will close.
18 MR. FLEMING: And e ven if you have a 19 vented structure yo u'l l end u p with basically a 20 helium-rich --
21 MEMBER MARCH-LEUBA:
Because the window 22 closed and did not allow air to come in.
23 MR. FLEMING: But meanwhile, so assume I 24 have a break in the helium pressure boundary if I've 25 lost my coolant. If I cool I'm not going to h ave any NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 187 1 graphite reaction at all. But if I have the heat up 2 what's going to happen is that my thermal expansion, 3 t he helium inside t he helium pressure b oundar y i s 4 going to expand and expel h eli u m o utside in the 5 reactor building.
6 And later on when the core cools down it 7 will start to bring in a helium-air mixture back into 8 the system. And the graphite phenomena i s analyzed as 9 part of the deterministic calculation.
10 So anyway, we're getting into a specific.
11 I think we can --
12 MEMBER MARCH-LEUBA:
I didn't w ant to get 13 into the specific but in my opinion all those purple 14 points should be analyzed only with the safety grade 15 components.
16 ACTING CHAIRMAN CORRADINI:
I d on't see 17 that. I don't think that was the intent. The intent 18 would be if the -- my interpretation of the process.
19 I could have this wrong.
20 If the uncertainty of t he purple -- that's 21 the color. If the u ncertainty o f t h e p urple points 22 starts essentially encroaching upon 10-4 t hen I w ould 23 have to include them. But if I'm sitting d own two 24 orders of magnitude lower I s ee no reason that I w ould 25 make that assumption as part of the analysis.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 188 1 MEMBER REMPE: And furthermore would you 2 be doing that with the current fleet? We d on't do 3 that with severe accidents i n t he curren t fleet. 4 You're asking us to take severe accidents and analyze 5 them with only safety -- a nd it may be even more 6 severe and the frequency would be much lower. So 7 what's the point?
8 MR. FLEMING: Well, the LMP approach when 9 y o u g e t to t he beyond design basis region there are 10 two points.
11 One is if you h appen t o have a high 12 consequence BDBE y ou h a v e to m ake sure that the 13 r eliability of the SSCs that keep it down ther e a r e 14 adequate and that gets into a safety classification.
15 It could be safety classified if it's n o t already 16 there for some other reason.
17 And then t he other open question is is it 18 risk-significant or not. If it's risk-significant it 19 could contribute to some of the NSRST.
20 MEMBER MARCH-LEUBA:
B ut you're telling me 21 it's not risk-significant b ecause the n on-safety 22 component is working. Let's drop it. I understand.
23 But do you understand.
You assume the low safety 24 grade device works.
25 MR. FLEMING: I don't a ssume i t w orks. I NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 189 1 calculate the probability it w orks, the probability it 2 fails. I look at the consequences when it works and 3 the consequences when it fails.
4 S o m e L B E s h a v e non-safety-re l a t e d f a i l i n g , 5 some ha v e t hem w orking. And when we get to the DBE 6 region w e're just g oing to extract out what w e're 7 going to call safety-related SSCs and we're going to 8 then calculate the DBA analyses only crediting those 9 SSCs. 10 We're trying to go through a process that 11 gets back into some kind of alignment w ith the 12 existing licensing process. And I forgot to mention 13 one of the constraints of the L MP framework is to 14 provide a set of licensing events, safety classes and 15 defense-in-depth evaluation that would fit within the 16 current regulatory structure.
B ecause something more 17 than that would require a r ulemaking and w o uld take 18 much longer to implement.
I t wouldn't meet the 19 objectives of the project.
20 MEMBER KIRCHNER:
What were the 21 assumptions.
I know this is just a specific example, 22 but how was the source term generated?
23 MR. FLEMING: Well, in t h e -- a lot of 24 this work came from the MHTGR work that was done back 25 in the nineteen eighties.
But t hey had computer c odes NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 190 1 and mechanistic source term m odels that would first --2 it would basically validate -- it wou l d d o the core 3 thermal response for the different accident sequences 4 for steam generator t ube rupture e vents. There w ould 5 be water ingress and graphite-water reactions to 6 consider.7 There's a whole mechanistic source term 8 white paper developed for the gas cooled reactors that 9 gets into the ph y sical and chemical processes of 10 those. So that's really w h a t was behind the source 11 terms for most of these.
12 XE-100 hadn't finished their design 13 specific s ource term calculation so we basically 14 scaled some information.
15 This was a d emonstration project. It 16 wasn't a real application. We just wanted to see if 17 it worked and if the design team thought i t was a 18 useful way to proceed and the answer was yes.
19 MEMBER DIMITRIJEVIC: Karl, since you're 20 familiar with pebble bed can you give me a couple of 21 examples f rom each category.
Thos e h ave s equences, 22 right?23 MR. FLEMING: Th e S , M and L are the 24 small, medium and large breaks in t he helium pressure 25 boundary.NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 191 1 MEMBER DIMITRIJEVIC:
Okay, so let's look 2 in small breaks. That's these, right?
3 MR. FLEMING: Yes, it's less than 10 4 millimeters.
5 MEMBER DIMITRIJEVIC:
So that small b reak 6 we have in every category.
7 MR. FLEMING: Yes, that's right.
8 MEMBER D IMITRIJEVIC:
So let's say --9 let's look at this 01, w hat is that, just small break, 10 nothing else?
11 MR. FLEMING: N othing else happened.
12 Circulating activity.
This had circulating activity.13 MEMBER DIMITRIJEVIC: And 02 which is in 14 design basis region, what is that?
15 MR. F L E M ING: It's probably a loss of 16 forced cooling event combined with a --
17 MEMBER DIMITRIJEVIC: Small LOCA.
18 MR. FLEMING: With a small.
19 MEMBER DIMITRIJEVIC:
A nd then when you 20 have in the beyond design basis events.
21 MR. FLEMING: We have th e l arge breaks 22 which a re the L's and t hen the steam generator 23 scenarios --
24 MEMBER DIMITRIJEVIC:
B ut let's say you 25 have SD03 or something, righ t. T hat's a small LOCA NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 192 1 with what now happen.
2 MR. FLEMING: I h ave t o g o back to the 3 event trees.
4 MEMBER DIMITRIJEVIC: So I have a little 5 problem that we call t hese e vents because they are 6 definitely not events, they are sequences.
7 MR. FLEMING: They're sequences.
8 MEMBER DIMITRIJEVIC:
-- small LOCA and a 9 small LOCA i s a design basis event. Here the s mall 10 LOCA --11 MR. FLEMING: I t's an event s equences.
12 They're event sequences.
Yes, they're e vent 13 sequences.
14 MEMBER DIMITRIJEVIC
- So why do we call 15 them events. That confused everybody who works on the 16 deterministic side of the thing, you know, that this 17 small LOCA here belong in every category.
18 MR. FLEMING: It would be more accurate to 19 say e vent sequences.
Yes, it would. All the LBEs are 20 event sequences in our approach.
21 ACTING CHAIRMAN CORRADINI: To make sure 22 that we're c atching Vesna's point is they're all 23 bundled.24 MR. FLEMING: They're all grouped.
25 MEMBER DIMITRIJEVIC: They're grouped in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 193 1 different groups.
2 MR. FLEMING: They're grouped i n families.3 MEMBER DIMITRIJEVIC: -- itself which is 4 small LOCA. The event as well.
5 MR. FLEMING: And Vesna, t here is a public 6 domain report where you can actually g et de t a i l ed 7 answers to all the questions, what is this sequence, 8 where is it in the event trees. It's all mapped out 9 in the report, the public domain report.
10 MEMBER DIMITRIJEVIC: Right.
11 MR. FLEMING: I didn't memorize --
12 MEMBER DIMITRIJEVIC:
No, no, n o, I k now. 13 It's a bunch of the sequences. I just want to point 14 out that --
15 MR. FLEMING: They're all event s equences.16 MEMBER DIMITRIJEVIC:
-- looking in 17 combination of systems and events.
18 MR. FLEMING: Absolutely.
19 MEMBER DIMITRIJEVIC: Right. So they're 20 calling this event, it's not an event anymore. It's 21 an actual sequence --
22 MR. FLEMING: They're event sequences.
23 MEMBER DIMITRIJEVIC:
It goes beyond -- it 24 will go beyond containment for light wat er reactor 25 here. I assume there is som e b uilding containment.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 194 1 So it is a total different, our understanding how is 2 treated is t otally different because i f you c ome to 3 the c hapter 15 that doesn't apply. And this w ill not 4 apply --5 MR. FLEMING: Fifteen is also sequences.
6 It says large LOCA, loss of offsite power.
7 MEMBER DIMITRIJEVIC:
But that's a 8 different assumption they ma k e f or large L OCA. For 9 small LOCA t hey would not have f our different 10 categories.
11 MR. FLEMING: Well, in the word 12 definitions we have t h e m. In the g uidance document 13 it's very clearly stated that all the LBEs are event 14 sequences. So that's our intent.
15 MEMBER DIMITRIJEVIC:
I just wanted to 16 make sure --
17 MR. FLEMING: I'm sorry for the c onfusion.18 MEMBER DIMITRIJEVIC:
-- all u nderstand 19 that that's what we've got.
20 MEMBER R E MPE: So to f ollow along o n that 21 they're really though, they're grouped. Like medium 22 break LOCAs are something bigger than such --
23 something else. It's a group o f s equences that are in 24 that event category. Or whatever.
25 MR. FLEMING: T he initiating event, in NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 195 1 this case there's basically four initiating events 2 that shut off. T hey're small, medium and large breaks 3 in the helium pressure boundary as initiating events 4 and those are defined by ranges. Ten millimeter, up 5 to 10 millimeter small, 10 to 65 millimeters, the size 6 of a fuel pipe is medium, greater than that's a large. 7 So that's the way we define it.
8 But then every L B E i s a f amily of e vent 9 sequences as Vesna points out t hat has the response of 10 the plant all the way out to the source term.
11 MEMBER REMPE: Characterized by that 12 sequence.13 MR. FLEMING: That's right.
14 M E M BER REMPE: Also, w hy are there n o 15 ATWS?16 MR. FLEMING: They're in there. They're 17 in there. For the M H T GR A TWS has no adverse 18 cons e quence. The reactor shuts down on negative 19 temperature coefficient.
20 MEMBER REMPE: And the s a me is true for 21 this XE-100.
22 MR. FLEMIN G: Yes. ATWS you don't have 23 like a pressure spike and a challenge to y our reactor 24 cool a n t s ystem. It doesn't in and of itself create 25 any different dose. I mean, we track them, we model NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 196 1 them, we calculate them.
2 MEMBER REMPE: It's just not showing up.
3 Okay.4 MR. FLEMING: And we put them in different 5 families be c a u s e we know there's interest to keep 6 track of that. But t hey don't j ump out on a frequency 7 consequen c e c h art a t all. For high temperature 8 reactors. And for a lot of these reactors.
9 MEMBER KIRCHNER:
S o Karl, just walk 10 t hrough if you would, please, what you do when y o u 11 have things on the cusp or on the margin. Let's just 12 pick one. Steam gener a t o r I assume that says s team 13 generator tube rupture 18 s itting right there at 1 14 times 10-4. 15 But it doesn't matter. I'm not asking the 16 specifics of the design o r a nything. Y ou have 17 something that lies c lose to that line. W hat happens 18 next?19 MR. FLEMING: Well, o kay. S o w e have 20 rules for h o w w e process each of t he three regions, 21 AOOs, DBEs and BDBEs.
22 And we a ls o n ot shown here will address 23 the uncertainties on the frequency and the dose. And 24 when we have a straddle situation or something comes 25 really close to th e line w e'll evaluate it on both NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 197 1 sides o f t he line. In other words we're not g oing to 2 get into one of these gee, if I can multiply by 0.98 3 where can I f ind a 0.98 factor and get below. W e 4 don't play those kinds of silly games if you will.
5 So we consider the uncertainties and if 6 we're close to the boundary we'll evaluate the event 7 as t h o u g h it's e ither a D BE or a BDBE and apply the 8 rules. S o we're not sensitive to the line i n the sand 9 problem.10 MEMBER KIRCHNER: Three decimal points.
11 MR. FLEMING: Right. May we go on?
12 MEMBER KIRCHNER:
B ut the assumption here 13 is w ith your m e c h a n istic source term y ou're not 14 assum i n g a significant failure in t he case of the 15 HTGR.16 MR. FLEMING: Well, we're trying to m odel 17 the actual phenomena that would dictate eith er the 18 retention or release of radioactive material and how 19 much.20 I'm going t o s ay a few words about the GE 21 demonstration.
22 MEMBER KIR C H N ER: Let me belabor this a 23 l i t tle bit because it's a n important point. Thi s 24 particular example benefits certainly from the amount 25 of effort that was i nvested in the MHTGR w hich NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 198 1 included a l ot of experimental work. Do you s e n se 2 that your colleagues understand the challenge that's 3 in front of them for developing mechanistic source 4 terms? Versus making an assumption in the LWR 5 business i s significant failure and proceed from 6 there.7 MR. FLEMING: I thi n k t h at's a good 8 question for some of our developers.
9 MR. REDD: I t hink that's a n excellent 10 question regarding mechanistic source term. But I 11 think i t also puts us on kind of a point Karl brought 12 up earlier that the uncertainties are there r egardless 13 of whatever approach we take, but we haven't found --14 at least f r o m the work we've d one we haven't f ound 15 these u ncertainties insurmountable or a nything like 16 that.17 Yes, experiments might need to be done to 18 help inform y o u r decisions but if you cycle through 19 the LMP process and you find that your uncertainties 20 even if they are large b ut that you're still okay with 21 t h at range of u ncertainties then maybe you can 22 d e monstrate t hat y o u don't h ave t o have such a n 23 extensive experimental program. You c ould actually 24 use it as a justification for not doing some work to 25 reduce uncertainties.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 199 1 So it depends a l ittle bit on the specific 2 case but I think at leas t having the LMP structure 3 there provides a way to prioritize uncertainties, 4 especially in an area like mec hanistic source term 5 where there could be uncertainties all over the place. 6 Some you might be able to live w ith and some you m ight 7 not be able to.
8 MR. REDD: Was that resp onsive t o your 9 question, sir?
10 MEMBER KIRCHNER:
Actually I w as making a 11 statement, a cautionary s tatement.
Just a s a designer 12 in the past I would j u s t submit that w hen the 13 uncertainties are large you design robustness into the 14 design.15 I hope that the DID, the defense-in-depth 16 process, that wo u l d b e a result that would come out 17 that you would go back.
18 And there are cliff effects for all t hese 19 designs that it's not just uncertaint y i n the s ense 20 how uncertain I am about my calculations. There are 21 real cliff effects for -- I won't enumerate them, but 22 for each of the designs on your t able that get you 23 into -- c ould you get into a situation where y ou have 24 significant release.
25 MR. FLEMING: Right. And just to confirm NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 200 1 it is something that's looked at v ery carefully as 2 part of the defense-in-depth adequacy evaluation.
3 MEMBER DIMITRIJEVIC:
I have one o ther 4 concern. Let's say that w e apply this to light w ater 5 reactor existing fleet w hich w e have m ost information.
6 Let's not even talking advanced light water reactor.
7 Every point will correspond to the release 8 category sequences, right?
9 MR. FLEMIN G: Well, also as I mentioned 10 earlier we w ant to captur e t he n o r elease sequences 11 a n d understand why we don't have a release. T hat's 12 fundamental to --
13 MEMBER DIMITRIJEVIC: All right.
14 MR. FLEMING: In the GE PRISM exercise 15 they started out with a P RA that was focused o n the 16 traditional reason for doing a P RA finding the risk of 17 severe accidents.
18 MEMBER DIMITRIJEVIC: I understand that.
19 MR. FLEMING: And they had to put more 20 emphasis o n the success states to do this process. 21 But anyway.
22 MEMBER DIMITRIJEVIC:
But I am more 23 interested in release. So this will correspond to the 24 risk category that is hundreds and hundreds of those 25 sequences.
If w e separate them l ike this, right, NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 201 1 base d o n i nitiator and where t hey belong we may 2 satisfy this a ll the time. But w hen you sum t hem the 3 large release may not satisfy.
4 MR. F LEMING: That's why we have the 5 cumulative -- we keep showing this slide but this is 6 o n l y used to look a t the risk s ignificance of 7 individual licensing event families.
8 We also have our cumulative risk targets 9 for the QHOs --
10 MEMBER DIMITRIJEVIC: Those have some --
11 MR. FLEMING: Where we aggregate for t hree 12 different metrics. O ne based on a Part 20 to look at 13 high frequency l ow dos e s c enarios a nd the two QHO 14 metrics. So we sum for those.
15 MEMBER DIMITRIJEVIC: So my -- one other 16 comment b ecause w e discussed this this m orning. This 17 curve it's not practical to apply to existing or l arge 18 light water reactor. I m ean, you know. That's one 19 insight. I don't see what would be point.
20 MR. FLEMING: The purpose of applying this 21 to a light water reactor was to revisit what are the 22 design basis accidents.
23 MEMBER DIMITRIJEVIC:
Well, b ut you're 24 talking design basis accident v ersus d esign b asis 25 sequences.
So we a re c hanging n ature of the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 202 1 regulation.
That's completely different issue. It's 2 a qualitative -- quantitative jump, so --
3 MR. FLEMING: I'll say a few words about 4 the GE demonstration.
G ary Miller i s h ere and also 5 David if there's questions on some of these aspects.
6 I'll sort of summarize this.
7 This is an e xample of an a pplication a fter 8 already d eveloping a design back i n the late nineteen 9 eighties and then taking advantage of this 10 modernization of the PRA project that was sponsored by 11 DOE a few years ago. There's a public domain report 12 on that by the way.
13 One of the features of the PRA that went 14 into this i s that they demonstrated the ability to 15 meet our PRA standards requirements for putting 16 together a compo n e n t reliability database for a new 17 kind of r eactor. Also for demonstrating passive 18 component reliability which is really -- it's 19 primarily an uncertainty analysis i n the phenomena 20 t h a t a re responsible for the passive heat removal 21 features and so forth, a nd a lso the mechanistic source 22 term.23 The PRA standard goes all the way out to 24 consequence analysis, radiological consequence 25 analysis and has separate requirements for mechanistic NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 203 1 source term. So they demonstrated the ability to meet 2 those requirements in their original PRA.
3 As I mentioned earlier the work they did 4 on the PRA modernization really had a big influence on 5 how we defined our risk significance criteria for the 6 LMP process.
7 So more r ecently s ince the PRA was 8 completed we did a demonstration that G E-Hitachi 9 performed and this went on for a number of months of 10 education process. We gave them a training p rogram on 11 the LMP p rocess and they came back with questions and 12 insights.13 It culminated in not a p u b l ic b ut a 14 meeting t hat was attended by the NRC staff and some of 15 the other advanced reactor developers just a f ew w eeks 16 ago.17 As I understand it a public domain report 18 will eventually be available on this exercise.
19 So, these are t he steps that they 20 performed.
They processed event sequence families 21 from their P RA into AOOs, DBEs a nd BDBEs. They did 22 sensitivity studies to derive what the required safety 23 functions were. And I'll let Gary spe a k to the 24 specifics there.
25 T h e y were able to come up with a NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 204 1 classification o f not only safety-related but non-2 safety-related with special treatment SSCs based on a 3 defense-in-depth adequacy evaluation of their p lant 4 capabilities.
5 They were able then to formulate what 6 their DBAs would look like following this process. 7 The N S R ST SSCs benefitted f rom the plant c apability 8 defense-in-depth evaluation.
9 Gary, would you l ike to elaborate a little 10 more?11 MR. MILLER: As y ou s aid you described the 12 proc e s s, the steps that we went through. This was 13 l imited in scope. It was internal events at p o w e r. 14 And particularly as we went down the line in looking 15 at defense-in-depth w e looked solely at t he heat 16 removal function. So we did a good deep dive but it 17 wasn't broad because scope, resources and t hings like 18 that.19 And as has been mentioned here before we 20 found a l ot of areas where the methodology made sense. 21 We learned a lot. We added in describing how but not 22 necessarily changing the m ethodology.
I think it was 23 pretty sound.
24 MR. FLEMING: This w as the safety-related 25 SSCs on the top part of this slide that they came up NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 205 1 with f or performing the required safety functions 2 which basically was controlled core heat removal, 3 controlled heat g eneration.
By doing those functions 4 for this reactor they assure the retention of 5 radionuclides in the fuel.
6 And also a s cope l imitation w as that they 7 only looked at the source o f radioactivity in the 8 fuel. T h e y didn't look at all the sources of 9 radioactivity.
T hey looked at some other s ources but 10 not all of them. Do you want to elaborate further?
11 MR. MILLER: You said it well, Karl.
12 MR. FLEMING: That's all right. I meant 13 to tee u p something f or you that I forgot to. T h e y 14 found that none of their non-safety-related SSCs were 15 risk-significant.
So z ero risk-significant SSCs. But 16 applying the defense-in-depth adequacy criteria and 17 particularly focusing on table 5-2 in the gu idance 18 document that talks about adequacy of p lant c apability 19 defense-in-depth they came up with four a dditional 20 items on here that would b e examples o f what c ould be 21 added to NSRST SSCs.
22 MR. MILLER: We u sed the frequency 23 consequence p lot quite extensively to look at not only 24 as y ou mentioned before borderline cases where we can 25 do sensitivity studies a nd evaluate taking a component NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 206 1 out of service o ne at a time, and t hen looking at the 2 resulting plot to see if it was in the DBE region or 3 in the cross hatched region.
4 A n d a s Karl said w hen we took it o ne by 5 one on each component none of them made it into the 6 cross h atched region b ased on that c riterion.
7 However, because this i s a v ery integrated process we 8 went through the defense-in-depth process a nd a sked 9 those questions.
10 We did in fact come up with what you see 11 there, the four areas of functions that did have some 12 safety significance. So those were NSRST.
13 ACTING CHAIRMAN CORRADINI:
So, help me --14 so this to me is important.
So you used the technique 15 which I am still fuzzy about t o u se defense-in-depth.
16 What d id you exactly d o? Can you go back to that 17 slide? The four systems, t he steam gene r a t or s hell 18 and tube design. I st i l l d o n't -- can you help me 19 what those four systems are and how they work?
20 M R. M ILLER: Okay. If y ou f ollow t h e 21 process and the detailed steps there's one step, I 22 think it's layer two, but whatever l ayer it is it 23 talks about what equipment do you need t o maintain 24 this within the DBE region. Not make it worse.
25 So you kind of l ook at one at a time what NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 207 1 would happen.
2 If we took certain equipment out of 3 service would it make it worse. In that case what we 4 found was that in general o ur heat remov a l is 5 adequately covered by the reactor vessel auxiliary 6 cooling system, that RVACS.
7 When you look at defense-in-depth in the 8 scope that the methodology mandates you determine that 9 not only that but the backup function would be having 10 to do with forced air cooling and along with t hat the 11 natural circulation f rom your intermediate heat 12 transfer system, and from there your steam generator 13 tubes and shell.
14 ACTING CHAIRMAN CORRADINI:
Okay. So let 15 me say it back to y ou so I make sure I understand.
So 16 your point i s RVACS is safety significant and 17 therefore at a one at a time application the 18 intermediate heat transfer system was not important 19 and the shell and t ube steam generator wasn't 20 important.
But if you t ook them a s a combination they 21 provided a defen s e-in-depth to the RVACS or vice 22 versa.23 MR. MILLER: Yes.
24 ACTING CHAIRMAN CORRADINI:
Have I g ot it 25 approximately right?
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 208 1 MR. MILLER: Yes.
2 ACTING CHAIRMAN CORRADINI:
O kay. S o then 3 because of that they would appear a s -- they w ould be 4 treated as non-safety treatment of --
5 MR. MILLER: Non-safety-related with 6 special treatment.
7 ACTING CHAIRMAN CORRADINI:
I w ant to say 8 RTNSS, but I'm not allowed to say RTNSS.
9 MR. FLEMING: Yes, non-safety-related with 10 special treatment. NSRST.
11 ACTING CHAIRMAN C ORRADINI:
Okay, f ine. 12 Thank you. And then what is SWRPS?
13 MR. MILLER: That is sodium water reaction 14 protection system.
15 ACTING CHAIRMAN CORRADINI:
So you're 16 looking for sodium leakage?
17 MR. MILLER: Yes. In the steam g enerator.18 MR. FLEMING: From the intermediate.
19 ACTING CHAIRMAN CORRADINI:
Are t hese 20 double walled steam -- I'm sorry to get t o details but 21 it matters. Are these double walled steam generator 22 t u bes where you have the helium g ap t hat y ou'r e 23 monitoring the helium gap?
24 MR. MILLER: No, that was not -- the 25 design was not a double wall.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 209 1 ACTING CHAIRMAN CORRADINI:
So what is 2 that? Is it a pressure measurement?
How do I detect 3 it i f I'm not tracking some sort of intermediate l ayer 4 in the steam generator tube?
5 MR. MILLER: Go ahead.
6 MR. GRABASKAS:
Typically it monitors for 7 hydrogen production up in the top of the s team 8 generator.
9 ACTING CHAIRMAN C ORRADINI:
Okay, f ine. 10 So it's a hydrogen sampling system. Okay, thank you.11 MR. FLEMING: Would you back up a slide?
12 I wanted to a lso mention that o n t he third bullet down 13 here questions that often come u p , how do you deal 14 with passive component reliability.
Another question 15 that will come up is you don't have any e xp e r i e n ce, 16 how are you going to d evelop a database.
A nd then 17 what about mechanistic source terms.
18 So I'm going to have David say a few w ords 19 about that. We actually have some public domain 20 papers out there on t his. W hat it's trying to do here 21 is m e e t t h e requirements in o ur n on-light w ater 22 reactor standard for these activities.
23 MR. GRABASKAS:
It's interesting.
I 24 mentioned that we kind of foresee these as issues but 25 it really goes back to the nineteen eighties and the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 210 1 PSID of PRISM and the NRC review.
2 If y ou l ook i n N UREG-1368 kind o f t hree 3 big i ssues the NRC called out with the PRISM P RA were 4 a s implified optimistic l ook at p assive system 5 reliabi l i t y , lack of a detailed treatment of source 6 term and then a lso q uestions about the component 7 reliability database.
8 So that was part of the r eason why we had 9 been focusing so much on that a t A rgonne, kind of 10 developing methodologies.
But t hen also with t he new 11 non-light water reactor P RA s tandard d eveloping 12 methodologies that also meet the requirements of the 13 standard.14 Because the standard can be really strict 15 in some of these areas, for example w ith passive 16 system rel i a bility. It's a requirement in the 17 standard t hat you need to mechanisticall y m o del the 18 response of the passive systems but also u sing models 19 that have been empirically v alidated through 20 experimentation too.
21 So it's r eally quite a strong step in this 22 PRISM P RA update and the LMP really gave us a good 23 c h a n ce t o demonstrate or actually run through th e 24 methodologies we had developed and we've refined them 25 because of the lessons learned because of it.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 211 1 Same with mechanistic source term too. We 2 had come up w ith the methodologies b ut this was a good 3 chance to actually apply t hem and g o through the 4 actual research and do the analyses.
5 MR. FLEMING: Thanks a lot.
6 CHAIRMAN BLEY: This is Dennis Bley. Two 7 things. The first is beneath the slide of -- papers 8 Karl referred to and you referred to and t h e o ther 9 issue is on the passive component reliability at l east 10 to m y thinking it's not so much component reliability 11 on passive s ystems as it is potential degradation over 12 time of t he passive functions because some are fairly 13 delicate balances.
Did that paper go into a 14 discussion of that area as well?
15 MR. GRABASKAS:
Yes. You're a bsolutely 16 right and I can provide a list o f references.
We have 17 a w hole bunch of public Argonne reports o n mechanistic 18 source terms but also the passive system reliability 19 approach too.
20 And you're right, that's the real big 21 tradeoff with passive systems is yes, you're running 22 on i nherent phen o m e n a but then your driving f orce 23 instead of b eing megawatt power e d p umps is now just 24 buoyance differences and t hings like tha t. So 25 properly characterizing those differences has a big NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 212 1 effect.2 But yes, I'll provide a whole list of the 3 open source references.
4 CHAIRMAN BLEY: O kay, and do that through 5 our staff at ACRS. Thank you.
6 MEMBER R E MPE: And t he tools you used for 7 the m e c hanistic source t erm were validated b ased on 8 EBR -- it's a metal f uel reactor, right. So it's EBR2 9 data? 10 MR. GRABASKAS:
A c ouple o f different 11 tools we used. Depending on what the tool did we 12 validated different ways. But on EBR2 data 13 experimentation.
U n fortunately in the SFR w or l d we 14 also have s o m e past accidents t hat we were able to 15 pull data from too.
16 But there are other tools t hat we actually 17 developed o urselves by demonstrating that the 18 importance was low for the outside consequences we 19 d i dn't have to validate to an extent that we m ight 20 have to validate other codes too.
21 PARTICIPANT:
It would be helpful if 22 p eople that are asking questions would use t h e 23 microphones.
24 MR. FLEMING: And to wrap up the G E P RISM 25 part of this show t h is was some of Gary's thoughts NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 213 1 about their feedback on the process.
2 MR. MILLER: O k a y , to wrap it up w e did 3 find that i t was very systematic and r e p e a t able 4 although i t may have seemed like it was advertised up 5 front. We did actually find that out.
6 It's pretty clear when a process step is 7 comp l e t e as we went through the methodology.
I say 8 that sensitivity studies a re e a s y t o perform but to 9 get there i t was a lot o f work. Setting up the logic, 10 the file structure, quantifications and all that, it 11 was quite a l ot of work to get there. But once you do 12 then y ou'd have a very easy way o f doin g a l ot of 13 sensitivity studies.
14 And this comes in handy in a lot of t hese 15 steps later on as well a s in tradeoff studies that you 16 might have later on down the road.
17 And then t he results are traceable t o key 18 risk and performance drivers. If you're familiar with 19 e v ent sequences and cut sets I think you know it's 20 easy to go back and l ook at what a re t he drivers, what 21 are the dominant failures and come b a c k to the risk 22 and performance drivers.
23 Another thing a s a developer we a ppreciate 24-- i t's more visual. It's more m e aningful than 25 talking about very low frequ e n c y numbers because as NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 214 1 you know y ou los e i n t e rest r ight away. It's not 2 relatable.
3 Where we can s how an FC plot with a p oint 4 or a group of points and then we can vary those b ased 5 on sensitivity studies it's much more meaningful and 6 it's much more relative.
You do a s ensitivity study, 7 you look at h ow much it moved, it's v ery clear to the 8 people.9 And then i terative.
Of course again as a 10 d eveloper I t hink in the early design phase w ith a 11 conceptual design and a conceptual PRA there a re a lot 12 of uncertainties and assumptions and w e document 13 those. And we get to t he p oint where s omething may be 14 on the line or something m a y h ave a very high 15 uncertainty distribution and that gives us a l ot of 16 options. We can l ook a t design c hanges or 17 programmatic changes there as well.
18 So we iterate that into the design and 19 then we update the model of course.
20 And overall i t just cl a r i fies a path to 21 regulatory engagement.
22 MR. FLEMING: Thanks a lot, Gary.
23 MEMBER MARCH-LEUBA: Just a question for 24 clarification.
If a component is non-sa fety g rade 25 according to this do you need to do seismic analysis NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 215 1 of i t? I'm asking s pecifically about t he s team 2 generator in P R I SM. If i t's non-safety grade you 3 don't h ave t o do the s eismic for it because it can 4 fail.5 MR. FLEMING: As part of our process a fter 6 we d e fined t he required s afety f unctions and our 7 safety-related SSCs once you've selected your external 8 hazard levels for your external events t hen there's a 9 requirement, it's an implied requirement that you have 10 to protect all of your safety-related S SCs so that 11 they wo u l d be able to perform the required safety 12 function in the event of an external event.
13 MEMBER MARCH-LEUBA:
According to your 14 methodology --
15 MR. FLEMING: And o ther non-safety-related 16 components would have to be protected like the seismic 17 two over one and those t ypes of issues come into p lay. 18 So there are w a y s for seismic requirements to c reep 19 into t he non-safety-related a rea through that pathway.20 MEMBER MARCH-LEUBA:
Okay. I'm just 21 surprised t hat when you apply the m ethodology it came 22 out t hat your steam generator is n ot safety grade. 23 It's not safety component.
Steam genera t ors are 24 things that fail everywhere and that's t he thing that 25 separated your sodium from y our water. I just cannot NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 216 1 b e l i e v e it c ame out no, we don't n eed it. I c a n't 2 believe it.
3 MR. MILLER: It's a n advanced reactor 4 passive. There's a lot of the r m al capacity in the 5 sodium. In reactivity --
6 MEMBER MARCH-LEUBA:
If it breaks you have 7 a fire.8 MR. FLEMING: Let's see. I think we 9 should go o n to the next and final part of our 10 demonstration activity ha v i n g to do with the molten 11 salt reactor experiment. And Steve Krahn is with us 12 to amplify on this.
13 There's a couple of different activities 14 that have been done. T h ere's a report indicated on 15 the right, a n Oak Ridge National Laboratory report and 16 a chart in the c e n t e r here which i dentifies some of 17 the processes that they're going through.
18 The report on the right is an example of 19 taking the technology they've b een collecting and 20 analyzing for the molten salt reactor experiment and 21 building a PRA model using the guidance that's in the 22 PRA whi t e p aper and then summarized m ore briefly in 23 the guidance document.
24 The diagram in the middle identifies a 25 process for performing process h azards analyses g iven NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 217 1 the fact that these molten s alt reactors resemble more 2 of a process plant than a standard or a typical type 3 of power generation reactor facility.
And they're 4 using a H AZOPs technology t o build the knowledge base 5 to b uild a PRA model a n d a deterministic safety 6 analysis model for the MSRE.
7 Steve, would you like to amplify on that 8 a bit?9 MR. KRAHN: I'll als o l o o p back and 10 disc u ss the source t erm q uestion which was a sked 11 earlier because obviously that's a primary concern. 12 And also if you look a t the dates on t hese reports 13 we're looking at early w ork in p rocess. So I w ould 14 also state that up front.
15 The source term in the molten s alt reactor 16 experiment was similar to most molten salt reactors is 17 split up into three large sections.
The vast majority 18 of the radioactive material is in the salt itself. 19 There's also radioactive material i n the offgas system 20 because the offgas system is continuously hooked up to 21 most of the -- is continuously hooked up to all of the 22 primary plants that I've seen.
23 And t h e n finally there is some m eans in 24 place to either polish or chemically clean the salt.
25 That is the third m ajor source o f radioactive NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 218 1 material.
2 The characterization of those t hree 3 radioactive material inventories is in the j oint 4 Vanderbilt-Oak R idge technical r eport on the r ight 5 which kind of started t his effort about t wo years ago, 6 a joint effort with Oak Ridge and Vanderbilt.
7 And one o f the things that that showed was 8 th e h a z a rd analysis for the m olten salt reactor 9 experiment was a very limited scope and very focused 10 on what was g oing on just in the salt system. So one 11 of the conclusions of the report was t he need to do a 12 broader hazard assessment that took into account all 13 of the other potential radioactive material sources as 14 well.15 So that has been worked on in parallel 16 with an Electric Power Research Institute p roject that 17 is w orking to document t he process to move from e arly 18 stage safety a nalyses such as HAZOP analysis, s uch as 19 failure modes and effects analysis through to 20 probabilistic risk assessment.
So t hat's w here t hose 21 two projects are being funded from.
22 If w e go t o t he next slide I can walk 23 through what we've learned to date and I'll expand a 24 bit on this summary.
25 The MSR lack any significant PRA legacy.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 219 1 So we're basically starting wi t h a clean s heet of 2 paper to look at what a PRA for a molten salt reactor 3 would look like.
4 That's why we -- after completing the case 5 study on the molten salt reactor experiment that was 6 documented in the Oak Ridge technical report we have 7 dropped back to do a comprehensive hazard assessment 8 of the molten salt reactor experiment.
9 That effor t i s winding down n ow. W e've 10 completed HAZOP studies on four major systems. One of 11 those has gone through peer review. The other three 12 are going through peer review right now.
13 And the next s tage -- one o f the things 14 that that showed us was that t he HAZOP is amenable to 15 providing the quote "comprehensive" hazard analysis 16 that's d esired by standards l i ke the non-LWR PRA 17 standard.
18 It also though supports early s tage safety 19 analysis p roviding i nsights b ack to t h e design team 20 an d allows preliminary modeling to be done for 21 probabilistic risk assessment.
22 It also supports ready identification of 23 potential risk important i nitiating events. And 24 that's the parameter or the outgrowth of HAZOP that 25 we're using to move forward t o the next s tage which is NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 220 1 going to be quantifying event t r e es, a t least one 2 major event tree for each of t hese rad i o active 3 material inventories in the molten salt reactor 4 experiment.
5 A couple of more lessons learned on this 6 early stage safe t y a n alysis f or the molten salt 7 reactor experi ment is it is valuable for providing 8 near term design and o perability i nformation.
One of 9 t h e things we identified in the Oak Ridge technical 10 report was where based on their simplistic
-- simple, 11 I don't want to say simplistic.
S imple hazard 12 analysis in the m id-nineteen sixties t hey had 13 identified five operating modes for the reactor.
14 In our detailed r eview of their o perations 15 report it turns out that there were really closer to 16 seven or eight o p e rating modes that they used on a 17 regular basis. That would have allowed a m u c h more 18 nuanced understanding of what their probabilistic risk 19 assessment would look like.
20 And then we also identified
-- one of the 21 other t hings that the early HAZOP a n a lysis does is, 22 and I think s ome of the members have been pointing out 23 this important factor, is it points out the need for 24 additional analyses.
25 Early on it shows t hings that we d on't NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 221 1 need and lets us evaluate whether o r n ot they need an 2 experimental program to be addressed or whether they 3 can be addressed by deterministic analyses.
4 For example, one of the ones that we are 5 in the middle of on the program with EPRI is looking 6 at freeze valves. Every molten s a lt reactor design 7 you look at uses freeze valves and they s how up on 8 schematic diagrams looking just like a standard gate 9 or globe valve but they are in fact a pretty complex 10 combination of an air system, an I&C system to 11 maintai n t h e temperature of that freeze valve and 12 continue t o maintain i t s isolation f unction or when 13 demanded melt and allow the molten salt to leave the 14 reactor.
15 That identification was done b y g oing 16 through the HAZO P s tudy for the molten s alt reactor 17 experiment and with some support from Southern Company 18 we're n ow in t h e process completing a failure m odes 19 and effects analysis for the important component that 20 freeze valves are.
21 The next steps o n t his f ront are w e're 22 working with Karl and Amir to look at how w e w ould 23 characterize and move forward t o d o licensing b asis 24 event identification and safety-significant component 25 identification and potentially if we d on't run o ut of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 222 1 time before now and the middle of March trying to do 2 some DID assessment as well. So that's where we are 3 on molten salt reactor work. I'm happy to answer any 4 questions.
5 ACTING CHAIRMAN CORRADINI: So you chose 6 what's called the MSRE?
7 MR. KRAHN: Correct.
8 ACTING CHAIRMAN CORRADINI:
Because t here 9 was enough information.
What about some o f t he 10 current conceptual designs?
11 MR. KRAHN: S o it wasn't the only criteria 12 we used t o select the MSRE. The other major criteria 13 is that not only was there enough design information, 14 it was a ll publicly a vailable and n ot covered by 15 intellectual property. So it was a quick way to get 16 things into the public domain.
17 MEMBER REMPE: B ut we were t old I believe 18 earl i er you're going to h ave a Kairos e valuation 19 coming soon.
20 M R. F LEMING: Yes. We're just in t h e 21 beginning stages of putting together a Kairos 22 demonstration and also a m icro rea ctor eVinci that 23 Westinghouse is developing.
So those are on t he b ooks 24 and we're launching o ff to get those completed by the 25 spring of 2019.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 223 1 MEMBER REMPE: T he p ublic information 2 question. Are all of these demos publicly available 3 documents, or at least available to ACRS? Earlier 4 Mike had asked for one and you said yes, we'll get you 5 that document.
6 MR. FLEMING: Well, the two that h ave been 7 completed, the GE PRISM a nd the XE-100 will be --8 well, XE-100 is available now and GE PRISM w ill be 9 a v a i lable i n the near future. T hey're p reparing it 10 now.11 MEMBER REMPE: Thank you. Go ahead.
12 CHAIRMAN BLEY: This is Dennis. I was a 13 little surprised on the discussion of the MSRE that it 14 focused on kind of starting from nuclear power plant 15 PRAs and that this was so different.
There have been 16 very, very m any chemical processing plant PRAs that it 17 kind of f ollows the way you described it, so i t w ould 18 have the (telephonic interference) probabilistic 19 hazards and how it -- and eventually to the PRA.
20 Did you look a t w hat's b e en done on the 21 chemical process industry in any depth?
22 MR. KRAHN: Yes, the HAZOP process which 23 does the initial qualitative hazard identification 24 work we took directly out of the chemical processing 25 industry.
I t is the standar d f o r doing t he initial NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 224 1 stages o f hazard assessment a nd e vent sequence 2 identification in chemical processing plants.
3 We will t h en move on to d oing PRA u sing 4 the LMP structure.
But we definitely t ook all 5 advantage that we could from chemical p rocessing 6 industry experience.
7 CHAIRMAN BLEY: O kay, that makes sense and 8 it isn't a great departure when you think of it from 9 that point of view. Thank you.
10 MR. FLEMING: Yes, to amplify on Steve's 11 answer t o D ennis's q uestion being a consultant to 12 their project we helpe d t h e m put together a body of 13 knowledge of prior wor k t h at w ould be relevant to 14 supporting the project.
15 Among the man y t h ings that we looked at 16 there was in f act a P RA done on the low activity w aste 17 facility at Hanford. It's p art of t heir vitrification 18 facility that was develope d n o t only to look at 19 radiological event sequences but a lso toxicological 20 event sequences.
21 And that provided s ome inputs i n the 22 knowledge base report.
23 CHAIRMAN BLEY: Okay, thanks.
24 MR. FLEMING: Thank you v ery much, Steve. 25 So coming -- this sort of concluding our technical NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 225 1 presentation today we c ome back to these quest ions 2 that are the L MP process was designed to a ddress what 3 a re the initiating events, event sequences a n d s o 4 forth. How does the design and t he SSC respond to the 5 event sequences. What kind of margins do we have in 6 the r esponse. And how the d efense-in-depth p hilosophy 7 is implemented.
8 We give y ou a lot of examples of different 9 applications at different l evels of development so 10 far. And if we have any more questions we'd be glad 11 to answer them.
12 ACTING CHAIRMAN C ORRADINI:
Committee 13 questions?
Okay. At this point let's take a b reak 14 because t here was none shown in the agenda but we need 15 a break. So we'll come back at 10 after 3.
16 (W h e r e u p o n , t h e a b o ve-entitled mat t e r w e n t 17 off t he r ecord at 2:54 p.m. and r esumed at 3:09 p.m.)18 ACTING CHAIRMAN CORRADINI:
Okay, why 19 don't we get started. E verybody settle down s o we can 20 have Herr Reckley lead us through this portion.
21 MR. RECKLEY: Okay, so to c lose o ut we 22 wanted t o g o through t he draft C ommission paper and 23 the draft regulatory guide because as I m entioned this 24 morning i n the end this is what the staff is producing 25 and it's what we would be asking the ACRS to comment NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 226 1 on, realizing it's inseparable from NEI 18-04 because 2 that's what we're proposing to endorse.
3 Before I get started though as personal 4 soapbox I g uess, they gave m e the m icrophone t hese 5 processes that have been described and as you're g oing 6 to s ee the staff is comfortable w ith there's a couple 7 of points to point out here I think.
8 One, just because you c an define some flow 9 charts and processes for what needs to be considered 10 doesn't mean that we think that this is simple. The 11 develop m e n t of a mechanistic s ource term with the 12 modeling of specific radionuclide groups across 13 barriers, which ones -- if y ou're talking about molten 14 salt which ones will stay in the s alt, which ones will 15 escape the s alt. Then for the ones that escape how 16 will they either be r etained or e s c ape from a 17 particular barrier. That's a complex physical 18 question.19 We can m odel t his out and s ay yes, the 20 developers need to do A, B and C and we're comfortable 21 saying that. At the same time we're not implying one, 22 that it's been done in all cases, and two, that it's 23 particularly easy in a ny case. So I just wanted to 24 lay out that as we lay out these processes we didn't 25 want to confuse the ability to define a process with NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 227 1 the fact t hat the science still needs t o be d one, 2 still needs to be proven.
3 Or at least the uncertainties i n the 4 science need to be accounted f o r. And that's what 5 Karl was talking about in much of the assessments in 6 some cases, how do you a ddress the uncertainties that 7 might exist for some of these designs.
8 So with that I'll get right into the two 9 documents that t h e s taff provided along with the 10 working draft of NEI 18-04.
11 The first one was a C ommission paper. The 12 staff's view is that a l t h o u gh much of t his has been 13 brought before the Commission before that t ime period 14 is measured in decades. And you can s ee that we made 15 great strides. One paper w as followe d b y another 16 paper albeit that paper was 10 years after the first 17 one.18 And so this will be really t he first time 19 that t he p rocess has been consolidated a nd applied or 20 available in a relatively integrated approach that we 21 want to bring before the Commission and say although 22 we t hink almost everything in here you've accepted in 23 previous p apers from the nineties or the early two 24 thousands this is the result of a c t ually applying 25 those decisions and what it looks like in a process.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 228 1 And we thought the Commission would want to see that 2 and have a shot at either saying yes, that's working 3 the way that was envisioned or not.
4 S o t he paper as it's defined h ere is to 5 seek the Commission approval. And it's divided into 6 a standard forma t. In enclosure 1 it gives the 7 background. I won't talk a lot about that one.
8 And then e nclosure 2 which summarizes this 9 approach really from N EI 18-04 and p uts it in the 10 context of where we thin k t here a re r eferences to 11 previous Commission decisions and where there might be 12 in one or two cases a r e m aining unanswered question 13 that this would provide the vehicle f or t he C ommission 14 to answer.
15 So going in t o the background this is very 16 similar to a slide I h ad earlier this morning. It 17 does start with t he Advanced Reactor P olicy S tatement.18 Whereas we d on't assume any p articular 19 design at this point can make it through t he process. 20 We're n ot p r e-judging the a bility o f any design and 21 how i t would turn out w e are assuming that the 22 Advanced Reactor Policy Statement defines attributes 23 of advanced reactors and w e're assuming that there is 24 an ability t o design a reactor that has t hose 25 attributes.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 229 1 And what that assumption gives us is the 2 ability to go forward without a particular design.
3 So that's supported by some of our 4 previous i nteractions like the p re-application 5 evaluati ons that were mentioned on PRISM on MHTGR. 6 The SECY paper 93-092, the Commission made a few s teps 7 in the direction that we're currently in but there are 8 also some differences in what was proposed in 1993 and 9 what's being proposed now.
10 SECY-03-0047 was the closest a nd that 11 probably m akes sense. That was at the time when some 12 other gas r eactors were being proposed and we were 13 interfacing w ith both developers, the Department of 14 Energy and others.
15 And so in SECY-03-0047 they proposed some 16 policy issues to the C ommission or some resolution of 17 policy issues that are directly applicable to today.
18 And again it's not surprising because as 19 Karl m entioned this methodology has been evolving 20 since the eighties starting with the MHTGR.
21 At the same time as I mentio n ed this 22 morning the related initiatives on risk-informed 23 performance-based regulation and those were largely 24 incorporated into the p roposals and t he policy issues 25 that were communicated to the Commission both during NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 230 1 the development of the l icensing strategy for NGNP and 2 actually in SECY-03-0047.
3 So the three big bullets f rom SECY-03-0047 4 that I want to mention w as tha t t he staff a sked 5 specifi c a l l y and the Commission stated in its s taff 6 requirements memorandum their a pproval of these t hree 7 things which i s that a greater e mphasis can be placed 8 on the u s e o f risk information and the use of 9 probabilistic risk assessments to identify events --
10 and here's the balancing of that -- provided there's 11 sufficient understanding of p lant and fuel performance 12 and that deterministic e ngineering judgment is u sed to 13 bound uncertainties.
So that's a general consensus of 14 a risk-informed p erformance-based approach using a mix 15 of risk-informed insights and deterministic 16 assessments i ncluding engineering j udgment w here 17 necessary.
18 The second is that a probabilistic 19 approach for safety classification SSCs is allowed.
20 And the last bullet there, that the single 21 failure criterion can be r eplaced with a probabilistic 22 reliability criterion.
23 So now the paper is orga nized into the 24 three primary e lements of the methodology, e vent 25 selection a nd analysis, SSC classification and NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 231 1 p e r f o r m a n c e c r i t e r i a , a n d d e f e n s e-i n-d e p t h 2 assessments.
3 And the key points in the paper are that 4 we think this process is consistent w ith that 5 recommendation and Commission approval from SECY 6 0047 to use a probabilistic approach to identify 7 events a nd to back that up w i th deterministic and 8 engineering judgment.
9 One thing that wasn't specifically 10 addressed i n previous papers and that is t hat as 11 you'll notice on the frequency consequence target 12 figure there is a lowe r f r e quency range and that is 13 often interpreted
-- w e t ry to caution not to 14 interpret this way as a hard PRA type cutoff.
15 But it is on the curve. The 5 times 10-7 16 value. And w hat we say in the p aper is we think that 17 those kind of values and considerations of when is a 18 frequency low enough that it need not be considered is 19 inherent in a risk-informed approach, but as we also 20 state in the guide and i n NEI 18-04 also states that's 21 not a h ard cutoff. You do need to look at 22 uncerta i n t i es. You need to look at potential c liff 23 edge effects a s was mentioned.
So you d o need to look 24 at the lower frequency events and make a conscious 25 decision if you're going to say something is a NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 232 1 residual risk that doesn't need t o be addressed within 2 the licensing basis events.
3 MEMBER SKILLMAN:
Yes, B i ll. For that 4 fourth bullet. Is there a backsto p? I could see a 5 clever anal y s t making the case for no containment 6 based on that fourth bullet.
7 MR. RECKLEY: The single f ailure criterion 8 bullet?9 MEMBER SKILLMAN:
I could see analyses 10 that indicate probability so low that one would then 11 say what had been a single failure c riterion r eally no 12 longer applies because the -- I'm down to E
-7 , E-8.13 A question is is there a backstop.
Is 14 there something that one would simply say 15 deterministically I really d on't care how low that 16 number is, by golly we're going to have a strong box.17 MR. RECKLEY: I w o u l d say the closest 18 within the m e t h o d o logy t o that i s the f act that you 19 don't rely on a single system o r a single feature 20 within the process.
21 And this was mentioned a little bit during 22 the other parts of the a ssessment, that really you're 23 looking at multiple failures and you're looking at it 24 at f requency ranges that go bel o w t he traditional 25 approach that was used for light water reactors.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 233 1 So, I see Ed standing there. Did you want 2 to?3 MR. WAL L A C E: I wasn't going t o l et you 4 dangle out there. The consideration here is looking 5 also at l ayers of defense available i n t he design and 6 having a single monolithic reactor with no m o v i ng 7 parts that could take c are of itself a nd start up and 8 shut down and do all the t hings it had t o do w ould be 9 one layer and that's all y ou'd e ver get to potentially 10 which is crazy. It's not sensible.
11 So part of the strategy that's described 12 in defense-in-depth looks beyond just the n umbers that 13 are showing up on the f requency consequence curve and 14 saying what other layers of defense do I have starting 15 with normal operations to keep the plant in g ood s hape 16 there, working through strategies of startup, 17 shutdown, AOOs and so forth to really understand the 18 robustness of the design.
19 And when you get to y our d es i g n b asis 20 event c ate g o r y and you establish what your DBAs are 21 you're s till looking beyond t hem for other things that 22 coul d (a) go wrong, part of the defense-in-depth 23 strategy at the end is go back to t he r isk triplet and 24 say what can go wrong, w hat's not in the PRA, all 25 those other kinds o f things and say am I satisfied NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 234 1 that these questions that arise because o f the 2 uncertainties at that stage of the de v e l opment have 3 been adequately taken care of.
4 S o what's b elow t he 5 times 10-7 number 5 they're still in the PRA but is there anything in 6 there that r eally is showing a s ignificant issue u ntil 7 you're looking at catastrophic --
8 MEMBER SKILLMAN:
Thank you. T hat helps. 9 Thanks.10 MR. WALLACE: I'm sorry, Bill.
11 MEMBER MARCH-LEUBA:
We w ent through this 12 discussion during the f unctional containment.
We all 13 agreed that a big strong box is the best containment 14 you could have. But I g uess as long as the 15 containment f unctions it doesn't need t o be a big 16 strong box. We had that discussion before.
17 MR. WALLACE: If I could add one thought 18 to that comment. We'r e trying to design a process 19 that would accommodate from test reactor size 20 commercial reactors to full fleet big reactors with a 21 common logic that you could follow as a designer and 22 developer and licensing reviewer.
23 So the flexibility is in t here to look at 24 all t hese things and to use the r isk insights you can 25 garner from all of t his information to say is this NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 235 1 really a threat to the public or not and then take 2 appropriate actions.
3 And it would be d ifferent at t he s mall end 4 of the spectrum.
Your answer might be in the l arge 5 end of the spectrum.
6 So the notion of functional containments 7 versus physical s ingle b arrier containments and things 8 like that, somewhere in the m iddle probably come into 9 play when your hazard gets large enough and then you 10 have to look at the other phenomena such as chemical 11 retention a nd the f uel or other things that will 12 affect the outcome.
13 MR. RECKLEY: As we look -- for any of 14 these designs as we look at t he mechanistic source 15 terms across the barriers g oing b ack to that F irst 16 Principles kind of approach and using the assessment 17 of t h e release fraction o r the attenuation factor 18 against each barrier for each radionuclide g roup, for 19 each event family is the way in the end will determine 20 what is n eeded at the end of that process perhaps for 21 a final structural barrier to the release. And then 22 a lso whether t hat needs to be a safety-relat e d 23 structure or if it i s only being t here to protect 24 against t he beyond design basis e v e nts w hether it 25 would b e a structure with s p e c i al treatment b ut not NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 236 1 necessarily safety-related.
2 The process would enable you to answer 3 those questions we believe.
4 MEMBER SKILLMAN: Thank you, Bill.
5 MR. RECKLEY: Going to safety 6 clas s ification again within the paper and as the 7 primary element of the p rocess. This was specifically 8 addressed i n the previous SECY from the 2003 time 9 frame and we think that it's consistent with that SRM, 10 staff requirements memorandum from the Commission that 11 allowed a probabilistic approach for the 12 classification of SSCs. So i t really w as not too much 13 of an issue there we didn't think f rom the C ommission 14 policy standpoint.
15 In assessing defense-in-depth again as 16 we've talked about n u m e r o us times today the p aper 17 provides a framework, it looks at both probabilistic 18 and d eterministic approaches, has a r ole for the 19 integrated d ecision-making process, i t does include 20 the verification that I think came up during the June 21 meeting that w e agree w ith and I don't think w as ever 22 really a technical issue but I t hink the guidance more 23 clearly s tates now that you'll never rely solely on a 24 particular plant design or operational feature.
25 The reason I bolded -- it's kind of hard NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 237 1 to tell b ut the last bullet is bolded because this is 2 s omething we want to bring up to the Commiss i o n 3 specifically.
4 In the following Fukushima and also t here 5 was another initiative, the risk management r egulatory 6 framework there were papers provided to the C ommission 7 recommending that we define and c ome up with criteria 8 for defense-in-depth.
9 The Commission's SRM c ame back and 10 specifically said don't do that. And that was largely 11 in the c ontext o f t he operating fleet and the 12 determination o f whether doing that could be 13 introduced basically as a change to h ow we were g oing 14 to look at the operating fleet.
15 So we want to point o ut to the C ommission 16 that this process does have a n assessment of defense-17 in-depth and is making a determination on the adequacy 18 of defense-in-depth.
And we point out we're not 19 proposing that this be u niversal.
We're not proposing 20 that it be forced on anyone.
21 However, for t hose p eople using this 22 process it d oes include a check on t he adequacy of 23 defense-in-depth and the Commission should b e aware of 24 it. 25 We don't think that's necessarily an NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 238 1 issue. In most of the discussions during the r i sk 2 management regulatory framework and even during the 3 recommendation 1 out of the Fukushima work there was 4 usually a distinction of what we w o u l d force o n the 5 operati n g f l eet and what would b e a good idea g oing 6 forward for example for advanced reactors.
7 It was generally acknowledged that a 8 voluntary approach like this f or advanced r eactors was 9 actually probably a good idea. It was j us t the 10 Commission wasn't going to mandate it.
11 But in any case t he r eason again w e wanted 12 to point this out to the Commission. You said don't 13 define a dequate defense-in-depth.
This process for 14 these reactors using t his methodology does include 15 that step.
16 MEMBER REMPE: Before you l eave this s lide 17 didn't you have an IOU that you p romised me from this 18 morning about t h e i ntegrated decision panel and any 19 sort of o ther interactions you'd had with such a p anel 20 in the past.
21 MR. RECKLEY: I did, but I didn't fulfill 22 it.23 MS. CUBBAGE: I f Hanh is still here we did 24 have a little bit of a side d i s c u s sion about the 25 integrated panel. He may be able to provide some NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 239 1 insights.2 MR. PHAN: Hanh Phan. I am the lead PRA 3 analyst in NRO. Regarding t he expert decision panels 4 the staff expected the appli c a nt will follow the 5 guidance in NUMARC 93-01 that's the guidance for the 6 Maintenance R ule 50.65, a nd f or n ew r eactors w e expect 7 the application would follow the guidanc e of the 8 process they use for the reliability assurance 9 programs in chapter 17.4.
10 MEMBER REMPE: Okay, so when I get my IOU 11-- or you're saying we have no experience. But what 12 I'm wanting to know is how well did it work. Not what 13 they should do --
14 MR. RECKLEY: And what I didn't do during 15 lunch was to actually track down some people from --
16 that were involved either in that 50 -- unless Marty 17 or H anh if you've been i nvolved in like a 50.69 review 18 or some other review that included a similar panel.
19 MR. PHAN: Yes, but at this point from the 20 NRO's or from the new reactor's perspective up to this 21 point t h e staff had the opportunity to look at the 22 meeting m i nutes from the expert panel c onducted for 23 other applications.
We not dir e c t ly participate in 24 any of those meetings but we review the m inutes and we 25 have insights and information from those.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 240 1 MS. CUBBAGE: And I think that's 2 appropriate as our r ole as the reg u l a tor. We 3 shouldn't be participating in those panels. Y es, it's 4 on I hope. So I t hink it s h o u l d b e a n auditable 5 process. It should f ollow the g u i dance that's 6 established. We wouldn't be participants.
7 MEMB E R REMPE: I'm not asking you to 8 participate. I want to know was it effective.
9 MR. RECKLEY: And I've got to get to the 10 righ t p e o ple who were involved in that kind of a 11 review that used a similar panel.
12 MEMBER REMPE: And a gain the re a s o n I'm 13 asking this i s I think there may be some devils in the 14 detail that haven't been fully fleshed out.
15 MR. RECKLEY: Yes. On i nfor m ing the 16 content of applications the draft guide does go into 17 a little bit more detail than NEI 18-04 on how we 18 think t hat t h e s e insights c an inform both the s cope 19 and the level of detail. So there w as some d iscussion 20 of that during today.
21 We generally agree w ith the discussion.
22 If I can say I got a sense of the m eeting if y ou will 23 that you should be able to use this process and if 24 things are less important t han the description can be 25 boiled d own to maybe some interface r equirements or at NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 241 1 least less detail on those systems.
2 An example that we have used t hroughout 3 the d evelopment of t his has been on t h e p ower 4 production side. And for light water reactors the 5 final safety analysis reports include a fair a mount of 6 discussion on the power conversion systems.
7 And that makes sense because the p ower 8 conversion systems can involve failures that feed back 9 to the primary system relatively quickly require the 10 actuation of safety equipment.
11 If a reactor design, an advanced reactor 12 design i ncludes the particular attribute within the 13 Advanced Reactor Policy Statement t hat the thermal 14 response of a react o r should b e much slower perhaps 15 the sensitivity to the power productio n systems is 16 much less and th e r efore the FSAR would not need to 17 provide as much information on the power p r oduction 18 systems, but just on t he i n t e r f ace and whatever 19 analysis is done to show that an upse t d o e sn't feed 20 back to the primary in quite as challenging a way as 21 it does for light water reactors.
22 MEMBER MARCH-LEUBA:
B ut this i s something 23 the s taff proposes to d o o n their own in your letter. 24 NEI 18-04 does not have it.
25 MR. RECKLEY: NEI 18-04 h ints a t i t but NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 242 1 it's not as clear. O ne of the things t hat w e're 2 talking a bout now is w hat will follow this p articular 3 guide. 4 And to the degree -- and this is a little 5 bit of what we're hearing, but I can't commit to it.
6 But one of the things that we're hearing is that the 7 developers would like a little more detail and a 8 little more c ertainty t hat we would be com fortable 9 with that kind of an approach.
10 And so this might be an a rea where we pick 11 to either do i t from the staff or w hat we would prefer 12 is t o work with a n industry group to develop guidance 13 that we could endorse similar to this process.
14 MEMBER MARCH-LEUBA:
The easiest -- the 15 least resistant path would be to hint in your letter 16 that it would be acceptable and then bring m e a ROC 17 (phonetic).
The next item that comes in bring me a 18 ROC. Now, the guy that has to bring the ROC will be 19 risking a lot.
20 MR. RECK L E Y: And that's one of the 21 reasons we're hearing that they would prefer to have 22 a little more guidance in this area.
23 And it's o ne of the r easons that we t ried 24 to expand on it in the draft guide to a t l e a s t s a y 25 that we're amenable to it. B u t in t he time that we NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 243 1 had we weren't able to provide much more detail than 2 actually what I'm giving here.
3 ACTING CHAIRMAN CORRADINI:
So let m e take 4 this a bit further. S o I asked the industry g roup 5 about this idea of pilots and classes and completing 6 the pilots so this p rovides a b asis. What's your 7 feeling about how that helps? Because in some sense 8 that puts it b ack in industry's court but essentially 9 t h e y w o uld develop enough of a pilot such that they 10 would help out the o ther parts of the industry in 11 terms of what's expected of t h e m t o actually go 12 through this effort. G o t h rough this e xercise. It 13 can be your personal opinion.
14 MR. RECKLEY: Well, i t's going to be my 15 personal opinion. The d ifficulty to some d e g r ee is 16 that even within a technology group t he designs can 17 vary significantly.
18 And what my personal thought i s that what 19 would be useful to everyone is t o k eep it technology-20 inclusive as this guidance is in which case you come 21 up with a methodology.
22 And what I just talked about, t he designer 23 would s ay -- the process would say what do you put in 24 chapter 10, that's typically power conversion, y ou do 25 an assessment.
What's t he f eedback f rom the secondary NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 244 1 to the primary and if you meet this then you d on't 2 need to describe.
3 However, if you do have f eedback and some 4 of the discussions were on chemicals so it may not be 5 thermal feedback, it might be chemical feedback. If 6 you have these kind of concerns then you do have to 7 describe in more detail what's in that adjacent system 8 because it has the potential to affect t he primary 9 side.10 And i t would lay o ut that k ind of a 11 process or m ethodology versus trying t o define 12 specifically what needs to be in for example chapter 13 10 for any design because all of those things become 14 dependent on the technologies, on the power levels, on 15 more factors than typically just one.
16 MR. TSC H L I TZ: So I would just add that 17 the industry recognizes t hat we need to do more as far 18 as risk-informing the content of applications beyond 19 what DG-1353 does and beyond what NEI 18-04 does.
20 There needs to be more guidance on this.
21 It's one of the things that we're looking at working 22 on in the near future to develop that extra guidance 23 on w hat g oes i nto the content of the application that 24 the NRC c ould review and endors e a s a n a cceptable 25 approach.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 245 1 ACTING CHAIRMAN CORRADINI:
So, can I say 2 that d ifferently.
So instead of them leaving it 3 general yo u m i g ht put some examples out there as to 4 what would be in and get their reaction as a group.
5 MR. TSCHLITZ:
Yes. I would say e ven more 6 that would be more of a guidance document to provide 7 how to go abou t doing this rather than just simply 8 examples.9 ACTING CHAIRMAN CORRADINI:
But I g uess 10 I'm s till bac k w ith the e xamples strike m e as 11 i m portant because within a class of systems there's 12 going to be some c ommonality and certain things, 13 chemical reactions you have t o consider, t he f act that 14 I don't h ave solid fuel and I have moving fuel, t hese 15 sorts of things are going to b e s imilar enough that I 16 would e xpect som e s ort of pilot would be b eneficial 17 for them to do and you to at least see to try to get 18 a reaction to it.
19 MR. RECKLEY: I generall y agree. It's 20 just a caution that the designs can vary and t hat can 21 lead you -- there was a q uestion earlier on about the 22 steam generator.
Well, if y our design u ses double 23 walled steam g enerators and the water is only a little 24 bit away from the primary sodium loop that's one l evel 25 of concern.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 246 1 If you're a design t hat uses an 2 intermediate loop and the water is one whole l oop away 3 from the primary side it's a different concern. T hose 4 are both fast reactors, sodium coolant but the designs 5 are significantly different.
6 So I'm glad to h ear Mike s ay that. W e've 7 heard it but now it's public.
8 This is another area, it's a little hard 9 here again to take that that's highlighte d o n the 10 slide. But this is another area that we don't think 11 the Commission has -- w e don't think there's a n issue, 12 but it's a lso not an i ssue that was brought up to our 13 knowledge in the previous Commission papers and that 14 we want them to ack n o w l e d ge that we're going t o use 15 this approach not to scale the NRC review but to s cale 16 what's in the application.
17 The discussion this morning on the 18 enhanced safety-focused review for example, that was 19 things the staff does different.
O nce w e g e t an 20 applicatio n i n , but the g uidance on what goes in an 21 application was basically the same. So NuScale gave 22 us a full application and then we said how can we 23 scale that back if you will. I'm shorthanding. How 24 can we adjust the review given the risk insights.
25 I think as John Monninger pointed out or NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 247 1 Ian that gets complex because now you are givi n g a 2 staff a c hapter and saying we don't think you need to 3 look at this in quite as much detail. That's an 4 engineering practice that's ha rd to come across to 5 give something to somebody a nd say but we don't really 6 need you to l ook at it in quite as much detail as you 7 typically have done in the past.
8 And so we think actually a b etter i dea is 9 to scale back what's i n the a pplication and what's 10 given to the staff to rev i e w v ersus giving them the 11 whole book and then telling t hem but you don't need to 12 look at t his in quite as much -- it's n ot human nature 13 to actually do that.
14 But that's an area w e're going to a sk the 15 Commission.
16 So a gain the recommendation is for the 17 Com m i s s ion to approve the use of this methodology 18 that's d escribed in 18-04 and as re f l e cted in the 19 draft guide.
20 You have a working draft of the guide so 21 I'm just going to kind o f quickly go through what's in 22 there and the staff findings.
23 The staff has taken no exceptions to 24 what's in NEI 18-04. We offer a n umber of things that 25 we want to emphasize or p erh a p s c larify but at this NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 248 1 time we're not proposing any exceptions. So this is 2 again just the scope of the draft guide and it is 3 applied to t h ose rules that are associated with the 4 content applications and t hey're listed there, 50.34, 5 52, 47 and so forth.
6 In regards to the licensing basis events 7 again the staff position as it's stated in the working 8 draft of the guide is that it's an acceptable method 9 as described in 18-04.
10 We c aution or emphasize that the FC target 11 does not depict acceptance criteria for the actual 12 regulatory limits. I t h i n k as Karl pointed out the 13 anchors that are used a r e surrogates.
They d on't 14 correlate to NRC regulations per s e. S o it's a useful 15 tool but you have to look at it for what it is and not 16 confuse it with actual acceptance limits.
17 The other point I already pointed out, the 18 figure includes a cutoff of 5 times 10-7 for inclusion 19 as a licensing basis event. The s taff again just 20 cautioning that's not a hard a n d fast cutoff. You 21 need to look below it. You need to address some 22 certainties.
You need to l ook f or cliff edge effects. 23 You need to be very deliberativ e i n what you're not 24 including in the licensing basis events.
25 We touched on this or Karl t ouched o n it. NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 249 1 The methodology d oes address external events. I t has 2 a definition o f a design basis external hazard level. 3 That is basically the same a s t he design b asis 4 earthquake, design basis flood, other external hazards 5 for which safety-related equipment needs to be 6 protected.
It sets that kind o f d efinitive limit. It 7 needs to be protected at least up to this point.
8 ACTING CHAIRMAN CORRADINI: Can you help 9 me here? If I'm in your -- I guess you've got a name 10 for the diagram. If I'm in the Rec k l e y-Cubbage 11 diagram.12 MR. RECKLEY: Segala.
13 ACTING CHAIRMAN C ORRADINI:
I'm sorry. 14 Segala-Reckley-Cubbage diagram. Is it just safety-15 related e quipment or is it r isk-signi f i c a nt? I'm 16 trying to understand what's covered under this.
17 MR. RECKLEY: Karl, be prepared.
Because 18 I will give you t he way I think it works and then Karl 19 can correct me if I'm wrong.
20 So for -- this is the alignment with the 21 current arrangement.
For safety-related equipment 22 they'll n eed t o be protected against the d esign b asis 23 external hazard level w hich is a nalogo u s t o and 24 determined using our existing methodology f or defining 25 those kind of external hazards.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 250 1 In a ddition t o that w i thin the P RA it's 2 looking at a fuller range of external events including 3 do w n i nto the beyond design basis a rena and to the 4 degree that beyond design b asis ex t e r nal hazard can 5 influence the frequency of an event or a malfunction 6 it's going t o be also addressed i n t hat c ategory of 7 events. So is that right, Karl?
8 MR. FLEMING: Yes, that's basically 9 correct. We start with -- w hen w e talk about the 10 design b asis external hazard levels we have a 11 requirement, a deterministic requirement that says 12 that you have to protect your safety-related SSCs in 13 the performance of your required safety functions to 14 achie v e s afe shutdown against any -- assuming the 15 occurrence of any design basis external hazard level. 16 And that's just for safety-related SSCs.
17 However, at some point in time and there's 18 flexibility on when this m ight occur, at some point in 19 time t here will be external hazards included into the 20 PRA and then that would then talk to the potential for 21 creating maybe additional risk-significant SSCs or 22 perhaps additional SSCs that because of the external 23 hazard may have a defense-in-depth adequacy 24 consideration.
25 So for those -- and therefore getting to NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 251 1 the NSRST cat e g o ries. And for a ll NSRST c ategories 2 whatever hazard they m ay have come f rom we set 3 reliability and capability requirements to basically 4 start the process of t he special treatments.
And then 5 the integrated decision process would consider is 6 there anything beyond setting reliability and 7 capability requirements which it may have to do with 8 protecting against an extern a l hazard or may not 9 depending on the nature of the LBE that produced the 10 risk significance or the defense-in-depth concern.
11 And the integrated d ecision panel w ould 12 then d ecide what kind of special t reatments beyond 13 capability reliability requirements and a monitoring 14 program to make sure that these are enforced through 15 the life operation of the plant.
16 MR. REC K L E Y: So, the other findings or 17 clarifications.
As we've already discussed the single 18 failure criterion as i t's applied traditionally to 19 safety-related equipment w ithin chapter 15 of l ight 20 water r eactors we think i s n ot needed a nd it's 21 consistent with the C ommission's decision in SECY-03-22 0047.23 We do offer again that the methodology in 24 NEI 18-04 does in our view use PRA a l ittle beyond 25 what is currently done. We require PRAs to be done.
NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 252 1 We require the results to be shown within chapter 19.2 It's used to support things like 3 determinations of regulatory treatment of non-safety 4 systems. But in this particular c a s e i t's a little 5 more integrated into the process.
6 And so we j ust offer the maybe obvious 7 observation that to the degree that the ASME ANS 8 standard i s c ompleted and to t he degree that that 9 s t a n d a rd is endorsed by t he NRC that would make the 10 process much easier.
11 And the staff does currently plan -- the 12 NRC is engaged in that standard.
Our understanding is 13 that that standard w ill be provi d e d to the NRC for 14 endor s e m e nt when it's completed, and the NRC will 15 review it for potential endorsement when it's 16 completed.
17 So all of these things are planned to be 18 looked at. We're just saying if it all works out as 19 planned it would help tremendously in the process.
20 ACTING CHAIRMAN CORRADINI:
Let me -- can 21 I ask a little bit d ifferent question.
Is this PRA 22 standard for advanced r eactors or advanced -- implying 23 a certain level of completeness of the design?
24 CHAIRMAN BLEY: We can't hear you.
25 ACTING CHAIRMAN CORRADINI: Is the level NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 253 1 of completeness of the design i m p lied in t his PRA 2 standard?3 MR. RECKLEY: S ince Karl's on the 4 committee let me.
5 MR. FLEMING: I'd be happy to handle t hat. 6 The standard does not enforce a given application.
So 7 the standard i s available t o support a variety of user 8 applications.
9 So the u ser decides and perhaps with 10 nego t iation with the regulator what p arts of the 11 standard need to be a pplied to that application, what 12 level of detail has to be supplied and so forth.
13 And then the s tandard has requirements to 14 clarify whether certain requirements haven't been 15 addressed o r whether there's been assumptions made in 16 lieu of a ctual inputs that would create the necessary 17 model fidelity.
18 So t he standard d ocuments the basis f or --19 r e quires y ou to document t he b asis for the PRA and 20 t h e n whether or not t hat's sufficient is r eally a 21 matter for the application process, i.e., negotiation 22 with the regulator.
23 MR. R E C KLEY: Because keep in mind from 24 the s taff's point of view we h ave the luxury o f b eing 25 at the t ail end of the design process. For the actual NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 254 1 application.
2 Interactions c an occur throughout the 3 design process but by the time they g i v e us the 4 application the assumption is t he design is c ompleted, 5 the requirements for things like PRAs are completed.
6 I would suggest though if you're looking 7 at h ow du r i n g the design process e ven b efore an 8 application is submitted that t he designer s can be 9 thinking in the context of the PRA what w as mentioned 10 earlier, the EPRI b ody o f k nowledge on going from 11 process h azard assessments to PRA and how you k ind of 12-- i t's especially applicable to molten salts, but 13 it's not only limited to molten salts. I t talks a bout 14 how y o u m ight start off doing PIRTs and again on 15 particular systems failure m odes and effects or 16 HAZOPs. Y ou'd use t hose tools that might be more 17 rea d i l y available for a d esign that's still b eing 18 developed and y o u mature into doing t he PRA through 19 iterations and in both the analysis a nd in the design 20 as you go along.
21 But I f o und that E P R I body of knowledge 22 document that was shown on the sli d e s to b e pretty 23 insightful of how a designer might do it.
24 MR. F LEMING: If I might just add a couple 25 of more comments on that topic. When the B oard of NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 255 1 Nuclear Codes and Standards decided we needed some 2 more standards for different kinds of r e actors they 3 set in place two w orking groups, one for adva n c e d 4 light water reactors and one for a d v a nced non-light 5 water reactors.
6 And those projects were going on in 7 parallel.
And we were guided by the JCNRM, the J oint 8 Committee on Nuclear Risk M a nagement t o take a 9 consistent approach to dealing with the same issues.
10 So this whole process of how do you w rite 11 a s tandard for a P R A that's done i n the m aybe 12 different stages of d esign was also faced with the 13 advanced light water reactor working group. A n d it 14 just turned out that our non-light water reactor 15 standard got issued for trial use bef o r e t he ALWR 16 standard got out.
17 But there's an ALWR trial use standard 18 that will be out pretty soon and it follows the same 19 logic as far as how d o you d eal with PRA requirements 20 for a design stage PRA.
21 A final comment is that we also have a PRA 22 white paper that was drafted several years ago, or a 23 couple of years ago I guess and o n e of our tasks in 24 the LMP framework is to bring our white papers up to 25 date and get them in alignment with what's currently NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 256 1 in the guidance document, taking into account lessons 2 from these pilot applications.
3 An d t h at includes s ome o f the standards Jas 4 (phonetic) has talked about there.
5 MR. RECKLEY: Then moving on t o the second 6 element, the safety classification.
Again, the s taff 7 position is that what's desc r i bed in N EI 1 8-04 8 provides an acceptable method.
9 And the only clarification o r point of 10 emphasis h ere again is these t hings n eed to be looked 11 at with all three elements as an integrated process.
12 Just again o ffering a c a u t i on that we d idn't w ant a 13 des igner t o pick out an element l ike safety 14 classification a nd t h i nk that that w as a s tandalone 15 process they could use.
16 Then lastly, defense-in-depth.
Again the 17 staff position, we're not t aking any exc e p t i ons and 18 saying that it's an acceptable method.
19 The only clarification here t hat w e're 20 offering and I'll be honest. These things were 21 developed in parallel so I have to go b ack and make 22 sure that NEI 18-04 as we've g iven it to you includes 23 the same statement.
24 But the revision right before that had 25 included a statement t hat talked about considering NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 257 1 plant capability and programmatic defense-in-depth 2 measures a nd change control processes t h a t w ould go 3 into the operating phase of a plant.
4 And we think t hat's a good i dea, but this 5 guidance document didn't really lay out much in t erms 6 of h ow that w ould carry into the o perating phase. And 7 we think that t h at is a g ood candidate for another 8 guidance development in terms of how do you maintain 9 this.10 There was some discussion for example on 11 all the programmatic measures that we would consider 12 duri n g licensing if you will to make sure that the 13 SSCs w ere actually delivering a s advertised.
But how 14 we r o l l t hat into the o perating phase a nd how we 15 include it in requirements like technical 16 specifications or plant procedures or regulations or 17 whatever form it takes w e weren't ready to address at 18 this point. So we're just leaving that o pen that this 19 only addresses up to t he licensing stage, not into 20 operations.
21 Two more slides here. We mention in the 22 draft guide the same thing I mentioned this morning.
23 There are interfaces between this process and NEI 18-24 04 and other arenas.
25 One is emergency planning.
And w e're NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 258 1 trying to make s u r e t h at the Draft Guide 1350 on 2 emergency planning and the Draft Guide 1 353 on 3 licensing basis events marry up b ecause as I mentioned 4 that's where the events will be id e n t ified that you 5 then compare to the protective action guidelines in an 6 application that includes a proposed r eduction in 7 emergency planning zones.
8 We've talked numerous times a bout 9 mechanistic source term. Mechanistic source term is 10 key t o this. It didn't get a whole lot o f d iscussion 11 i n N EI 18-04. It's an inherent assumption t hat y o u 12 have the ability to assess the conseque n c e s or as 13 previously stated the r elease fractions across a ll the 14 barriers.
15 So we're just pointing out that link and 16 that importance.
17 This is another area that we envision it's 18 very possible that we'll have an additional guidance 19 document on t he development of mechanistic source 20 term. And if for no other reason than the ACRS kind 21 of suggested that that m ight be a good idea in the 22 context of the emergency planning proposed rule.
23 So we don't really disagree with that and 24 we're talking about it. And that is another good 25 candidate for another guidance document that would be NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 259 1 developed.
2 ACTING CHAIRMAN CORRADINI:
It was pointed 3 out in that session. Dennis was the chair of that 4 session also and he c an remind me if I have it wrong.5 In Reg Guide -- now I'll get the r eg g uide 6 wrong, 1.18 -- 1.83, 1.183. I can't remember the reg 7 guide for essentially a lternative source term. T here 8 was a s et of seven or eight attributes that if the 9 applicant wanted not to use what is in the reg guide 10 b ut wanted to use s o mething o f their own making i t 11 ought to meet a series of attributes. And I thought 12 at least that's a good starting point.
13 MR. RECKLEY: That is a good s t a r ting 14 point. Under NGNP there w a s a white p aper on 15 mechanistic source t erm. F or other designs t h e re's 16 also for fast reactors Argonne has produced a report 17 on mechanistic source term.
18 So there is -- we actual ly are working 19 with -- under our contract a rrangements we're working 20 with some n a t i o nal labs i n a similar context t o say 21 can we develop a fairly g eneric wa y t o describe the 22 development of a mechanistic source term.
23 So it was a good observation and I think 24 it's likely that we'll be here sometime down t he road 25 to talk a bout a d raft guide on m echanistic source NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 260 1 term.2 I've already talked numerous times about 3 informing t he content a pplications.
T here is a s hort 4 section in the draft guide that starts to talk about 5 it as we've talked about b efore. Maybe it doesn't go 6 far enough b ut it was at least a starting p oint to 7 include in the draft guide that you can scale the 8 format and the content and the level of detail in an 9 a p p l ication based on the insights y ou get from this 10 methodology.
11 S o going r ight to the bottom line her e. 12 Checking off that w e were h ere today, O c t o ber 30. 13 F ull committee the first week o f December.
I'm n o t 14 sure it's the 6th, but w hatever date gets set for that 15 first week o f December w e'll come back t o the full 16 committee.
17 And again what we're a sking for is 18 feedback o n the draft Commission paper and at your 19 leisure or a t your discretion feedbac k o n the d raft 20 guide.21 We then plan after the full committee to 22 issue t h e d raft guide by the end of the year is our 23 current plan. Issue the S ECY to the Commission in 24 early 2019.
25 In mid-2019 depending on the feedback that NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 261 1 we get from the solicitation of public comments on the 2 draft guide a n d whatever f eedback w e g et f rom the 3 Commission on the SECY paper we would b e in a position 4 to finalize the guide and then s tart to engage the 5 ACRS on the review of the f inal guide a nd issue the 6 final guide we hope by the end of 2019.
7 ACTING CHAIRMAN C ORRADINI:
T hank you, 8 Bill. Questions by the committee before we go to 9 public comments? Okay. I think the line is open in 10 our new high-tech r oom. So f irst l e t's go with 11 there's comments from the members of the public that 12 are in the room. Any additional comments by members 13 of the public in the room? Okay.
14 So l et's turn to th e p hone line, bridge 15 line. Are there any comments f rom members of the 16 public? Okay, hearing none. Oh, I'm sorry. Mr.17 Redd. Oh, you have a homework assignment.
Let's make 18 sure we have no public -- so there's no public 19 comments from the bridge line.
20 Okay. Come up with y our homework 21 assignment.
22 MR. REDD: Jason Redd, Southern Nuclear.
23 We talked several times today about the public report 24 that h a s been issued o n the X-Energy demonstration.
25 I'd like to read that ADAMS s e s s i on number into the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 262 1 record so it will be available in the future.
2 That is ADAMS number ML18228A779 d ated 3 August 1, 2018. Thank you.
4 ACTING CHAIRMAN CORRADINI:
Thank you very 5 much. I am pulling it up as we speak just to see if 6 it really is there. I think what I got with that ML 7 number is presentation September 13, 2 018 public 8 meeting o n regulatory improvements.
But not that the 9 ADAMS system is disorganized.
10 MR. REDD: All right. T h a t may be the 11 overall package number.
12 ACTING CHAIRMAN CORRADINI: Oh, it's the 13 whole package. Okay, excuse me.
14 MR. REDD: I will re-verify this again.
15 ACTING CHAIRMAN CORRADINI:
I t hink that's 16 the best thing to do.
17 MR. RECKLEY: We'll get it and the other 18 Argonne repor t s and the things that were m entioned.
19 We'll get to ACRS staff.
20 ACTING CHAIRMAN CORRADINI: Okay. Thank 21 you very much. Dennis, I want to kind o f turn to you 22 since you're the actual chair. I'm just the in room 23 chair. Do you have any final comments you want to 24 make, Dennis?
25 CHAIRMAN BLEY: I was on mute. T h a nks, NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 263 1 Mike , a n d thanks for chairing the meeting in my 2 absence. I appreciate it.
3 I think we need to talk a little bit a bout 4 the full committee meeting. Today's meeting had 5 almost the w h o l e committee, I think we're missing 6 three people.
7 So right now we're scheduled for an hour 8 and three quarters.
And I think that's going to be 9 okay.10 Bill, I think pretty muc h a summary of 11 what you p resented today and I don't know if Karl 12 Fleming can be there b u t t h ere may be some detailed 13 questions on t he methodology and I think that would be 14 really good if you had somebody to take that.
15 So we'll -- o u r staff a nd the NRC s taff 16 will work together to get an agenda set up for this 17 meeting.
18 I think we're probably going to dr a f t a 19 letter on b oth the C o m mission paper and the new 20 guidance doc u m e nt. I don't see why we wouldn't 21 include them both.
22 And I'd l i k e to thank everybody f or a 23 great meeting. A lot of good information.
So I t hink 24 that's w h ere we're headed. If any members have any 25 thoughts about t h e f ull c ommittee meeting or the NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 264 1 letter I'd love to hear them.
2 ACTING CHAIRMAN CORRADINI: Okay. We'll 3 come back then to the staff and t ry to prepare for the 4 full committee.
Okay. With industry input o f course. 5 Other than that I t hink we're done and 6 we're adjourned. Thank you.
7 (W h e r e u p o n , t h e a b o v e-e n titled matter we n t 8 off the record at 4:09 p.m.)
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEA L R. GROSS COURT RE PORTE RS A ND TRA N SCRI B E RS 1323 RHODE I S LA ND AV E., N.W.(202) 234-4433 W A S HI NGTON, D.C. 20005-3701 (202) 234-4433 October 30, 2018 (AM)1ACRS Future Plant Designs SubcommitteeDraft Regulatory Guide (DG) 1353 andRelated Commission Paper "Technology
-Inclusive, Risk
-Informed, Performance
-Based Approach to Inform the Content of Applications for Licenses, Certifications, and Approvals for Non
-Light Water Reactors,"
2Outline*Background
-Enhanced Safety Focused Review Approach (ESFRA) for Light-Water Small Modular Reactors
-Non-Light Water Reactor Program
- Context and overview for technology
-inclusive methodology
- NEI 18-04 (Licensing Modernization Project)
- Draft SECY paper
- Draft Regulatory Guide 1353
- Staff approach used for NuScale application review to focus on safety
- Tools and strategies for defining the scope and depth of reviews
- Companion to NUREG
-0800 (Standard Review Plan), Introduction
-Part 2 as well as Design
-Specific Review Standards
- Intended to be used during both pre
-application and review stages 3Enhanced Safety Focused Review Approach (ESFRA)
- Objective-Increased effectiveness and efficiency for staff reviews*Directed by the Commission
-SRM to COMGBJ 0004/COMGEA 0001-SRM to SECY 0024*Review focus and resources-to risk
-significant structures, systems, and components (SSCs) and other aspects of the design that contribute most to safety*ACRS presentations in 2011, 2016, and 2017 4ESFRA Background
- Considerations
-Safety Significance (e.g., A1/A2/B1/B2)
-Regulatory Compliance
-Novel Design
-Shared SSCs/Nonsafety
-Safety Interactions
-Unique Licensing Approach
-Safety Margin/Defense
-in-depth-Operational Programs
-Additional Risk Insights 5ESFRA Review Tools
- Applied in multiple areas with varying degrees of success*Developinglessons learned
- Can be used for future reviews including advanced reactors-Coordination with LMP
- The underlying concept is consistent with the agency's risk
-informed, performance
-based approach 6ESFRA Status and Future 7Advanced Reactor Program 8Implementation Action PlansStrategy 1Knowledge, Skills and CapabilityStrategy 2Computer Codes & Review ToolsStrategy 3Flexible Review ProcessesStrategy 5Policy and Key Technical IssuesStrategy 6CommunicationStrategy 4Consensus Codes and StandardsONRL Molten Salt Reactor TrainingKnowledge ManagementCompetency ModelingRegulatory RoadmapPrototype Guidance Non-LWR Design CriteriaASME BPVC Section III Division 5ANS Standards20.1, 20.230.2, 54.1Non-LWRPRA StandardSiting near densely populated areasInsurance and LiabilityConsequence Based Security(SECY-18-0076)NRC DOE WorkshopsPeriodic Stakeholder MeetingsNRC DOE GAIN MOUIdentification & Assessment of Available CodesInternational CoordinationLicensing ModernizationProjectFunctional Containment (SECY-18-0096)EP for SMRs and ONTs(SECY-18-0103)EnvironmentalReviewsPotential First MoversMicro-ReactorsUpdated HTGR and Fast Reactor Training 9Integrated Design/ReviewConsequence Based SecurityEP for SMRs and ONTsFunctional Containment Insurance and LiabilitySiting near densely populated areasEnvironmentalReviews 10Revisit First Principles 11Integrated Design/ReviewConsequence Based SecurityEP for SMRs and ONTsFunctional Containment Insurance and LiabilitySiting near densely populated areasEnvironmentalReviewsLicensing ModernizationProject 12Other Requirements
- Associated requirements include:
-Quality Assurance
-Maintenance Rule
- Interfaces with requirements for:
-Siting-Emergency Preparedness
-Environmental Reviews
- Additional requirements for design/operation include:
-Routine Effluents
-Worker Protections
-Security-Aircraft Impact Assessments 13NEI 18-04, General Approach
- Licensing Basis Events
-Probabilistic Risk Assessment
-Deterministic
- SSC Classification
-Function and Risk Considerations
-Safety Related
-Non-Safety Related with Special Treatment
- Defense-in-Depth Assessment
-Structures, Systems and Components
-Programmatic
-Integrated Decision
-making Process
- Evolution of Approach
-Advanced Reactor Policy Statement
-SECY-93-092, "Issues Pertaining to the Advanced Reactor (PRISM, MHTGR, and PIUS) and CANDU 3 Designs and Their Relationship to Current Regulatory Requirements"
-Risk-Informed, Performance
-Based Regulation
-SECY-03-0047, "Policy Issues Related to Licensing Non
-Light-Water Reactor Designs"
-NUREG-1860, "Feasibility Study for a Risk
-Informed and Performance
-Based Regulatory Structure for Future Plant Licensing"
-Next Generation Nuclear Plant (NGNP)
- Similarities to traditional LWR structure, but also differences
-including terminology challenges with different definitions for some phrases 14Key Considerations 15Key Considerations (continued)
- Integrated methodology consisting of three primary elements-Licensing Basis Event Selection and Analyses
-SSC safety classification and performance requirements
-Assessing defense-in-depth adequacy
- Uses existing regulatory criteria, including guidelines for offsite dose and NRC safety goals
- Assessments performed using risk
-informed and deterministic approaches, including Integrated Decision-making Process*Includes methodology for assessing defense in depth provided by plant capabilities and programmatic controls AOOsDBEsBDBEs 16Event Selection & AnalysisNote that DBAs (Chapter 15) derived from DBEs
- F-C Target considered along with cumulative risk metrics, safety classification, and assessment of defense in depthThe F-C Target values shown in the figure should not be considered as a demarcation of acceptable and unacceptable results. The F
-C Target provides a general reference to assess events, SSCs, and programmatic controls in terms of sensitivities and available margins.
17Safety Classification and Performance Criteria
- Safety-Related (SR):
oSSCs selected by the designer from the SSCs that are available to perform the required safety functions to mitigate the consequences of DBEs to within the LBE F
-C Target, and to mitigate DBAs that only rely on the SR SSCs to meet the dose limits of 10 CFR 50.34 using conservative assumptions oSSCs selected by the designer and relied on to perform required safety functions to prevent the frequency of BDBE with consequences greater than the 10 CFR 50.34 dose limits from increasing into the DBE region and beyond the F
-C Target*Non-Safety-Related with Special Treatment (NSRST):
oNon-safety-related SSCs relied on to perform risk significant functions. Risk significant SSCs are those that perform functions that prevent or mitigate any LBE from exceeding the F
-C Target, or make significant contributions to the cumulative risk metrics selected for evaluating the total risk from all analyzed LBEs.
oNon-safety-related SSCs relied on to perform functions requiring special treatment for DID adequacy
- Non-Safety-Related with No Special Treatment (NST):
oAll other SSCs (with no special treatment required) 18Assessing Defense in Depth
19Informing the Content of Applications
- NEI 18-04 provides useful guidance for applicants to identify and provide the appropriate level of information needed to satisfy parts of the regulatory requirements in 10 CFR 50.34, 10 CFR 52.47, 10CFR52.79, 10 CFR 52.137, and 10 CFR 52.157.
- Combination of deterministic evaluations and probabilistic risk assessments
- Information needed on fuel, primary, and other barriers to define limitations, performance characteristics, and as input to mechanistic source term
- Information needed on SSCs and programmatic controls associated with key safety functions
- Scope and depth for other information (e.g., ancillary plant systems) to be determined based safety/risk significance (i.e., roles in preventing or mitigating licensing basis events)*Level of detail can also reflect potential performance
-based approaches (see Introduction, Part 2, to NUREG 0800) 20Next Presentations
- NEI 18-04, "Risk-Informed Performance
-Based Guidance for Non-LightWater Reactor Licensing Basis Development," (Draft Report Revision N) and Related Tabletop Exercises
- Requested ACRS Feedback
-Draft SECY, "Technology
-Inclusive, Risk
-Informed, and Performance
-Based Approach to Inform the Content of Applications for Licenses, Certifications, and Approvals for Non-Light Water Reactors"
-Draft DG-1353, "Guidance for a Technology
-Inclusive, Risk-Informed, and Performance
-Based Approach to Inform the Content of Applications for Licenses, Certifications, and Approvals for Non
-Light Water Reactors"
October 30, 2018 (PM)1ACRS Future Plant Designs SubcommitteeDraft Regulatory Guide (DG) 1353 andRelated Commission Paper "Technology
-Inclusive, Risk
-Informed, Performance
-Based Approach to Inform the Content of Applications for Licenses, Certifications, and Approvals for Non
-Light Water Reactors,"
- Paper-The purpose of this paper is to seek Commission approval of the U.S. Nuclear Regulatory Commission (NRC) staff's recommendation to adopt a technology
-inclusive, risk
-informed, and performance
-based methodology for informing the licensing basis and content of applications for licenses, certifications, and approvals for non
-light-water-reactors (non
-LWRs). *Enclosure 1, "Background"
- Enclosure 2, "Technology
-Inclusive, Risk
-Informed, Performance
-Based Approach"2Draft SECY Paper 3Policy Background
- Advanced Reactor Policy Statement
- Pre-application evaluations (e.g., PRISM, MHTGR)
- SECY-93-092, "Issues Pertaining to the Advanced Reactor (PRISM, MHTGR, and PIUS) and CANDU 3 Designs and Their Relationship to Current Regulatory Requirements"
- SECY-03-0047, "Policy Issues Related to Licensing Non-Light Water Reactor Designs"
- Related initiatives to develop and implement risk-informed, performance
-based regulation 4Policy BackgroundSECY-03-0047, "Policy Issues Related to Licensing Non-Light Water Reactor Designs,"and the related staff SRM dated June 26, 2003.
- Greater emphasis can be placed on the use of risk information by allowing the use of a probabilistic approach in the identification of events to be considered in the design, provided there is sufficient understanding of plant and fuel performance and deterministic engineering judgment is used to bound uncertainties;
- A probabilistic approach for the safety classification of structures, systems, and components is allowed; and
- The single
-failure criterion can be replaced with a probabilistic (reliability) criterion.
5Event Selection
- Consistent with SRM approving the use of a probabilistic approach to identify events provided there is sufficient understanding of plant and fuel performance and engineering judgment is used to address uncertainties
- Including a lower frequency range for licensing basis events, when combined with other considerations and engineering judgement, is an inherent part of a risk
-informed approach and is consistent with the Commission's SRM
- The F-C targets support defining needed SSC capabilities and reliabilities to support the design process and to inform the content of applications, considering uncertainties and multi
-module issues
- Consistent with the Commission's SRM approving replacement of the single
-failure criterion with a probabilistic (reliability) criterion 6Safety Classification & Performance Criteria
- The safety classification of SSCs and determination of performance criteria are directly related to and performed in an iterative process along with the identification and assessment of LBEs and the assessment of defense in depth
- Systematic approach to assessing and determining appropriate relationships between the needed capabilities and reliabilities for SSCs and the role of those SSCs in mitigating and preventing LBEs 7Assessing Defense in Depth
- Framework that includes probabilistic and deterministic assessment techniques to establish defense in depth using a combination of plant capabilities and programmatic controls
- Assessments performed using several approaches to assess a reactor design and determine if additional measures are appropriate to address an over
-reliance on specific features or to address uncertainties
- Includes verification that two or more independent plant design or operational features are provided to meet the guidelines for each licensing basis event
- Methodology includes use of an Integrated Decision
-Making Process *Staff is not proposing to more universally define DID criteria and seeks Commission acceptance of the NEI 18-04 approach for this specific case.
- 8Informing Content of Applications
- NEI 18-04 provides useful guidance for reactor designers and the NRC staff for selecting and evaluating licensing basis events, identifying safety functions and classifying SSCs, selecting special treatment requirements, identifying appropriate programmatic controls, and assessing defense in depth
- Taken together, these activities support documenting the safety case and determining the appropriate scope and level of detail in applications for licenses, certifications, or approvals for non
-LWRs 9RecommendationThe staff recommends that the Commission approve the use of the technology
-inclusive, risk
-informed, and performance
-based approach described in NEI 18
-04 and DG-1353 for identifying LBEs, classifying SSCs, and assessing the adequacy of defense in depth. These key aspects of the proposed approach will also be used to inform the appropriate scope and level of detail for information to be included in applications to the NRC for licenses, certifications, and approvals for non-LWRs.
10Working draft DG 1353 Scope
- Methodology supports identifying the appropriate scope and depth of information provided in applications for licenses, certifications, and approvals
-10 CFR 50.34, "Contents of applications; technical information," describes the minimum information required for (a) preliminary safety analysis reports supporting applications for a construction permit, and (b) final safety analysis reports supporting applications for operating licenses.
-10 CFR 52.47, "Contents of applications; technical information," describes the information to be included at an appropriate level in final safety analysis reports supporting applications for standard design certifications (DCs).
-10 CFR 52.79, "Contents of applications; technical information in final safety analysis report," describes the information to be included at an appropriate level in final safety analysis reports supporting combined licenses (COLs).
-10 CFR 52.137, "Contents of applications; technical information," describes the information to be included at an appropriate level in final safety analysis reports supporting standard design approvals (SDAs).
-10 CFR 52.157, "Contents of applications; technical information in final safety analysis report," describes the information to be included at an appropriate level in final safety analysis reports supporting manufacturing licenses (MLs).
11Working draft DG 1353 FindingsLicensing Basis Events
- Staff Position: NEI 18-04 provides an acceptable method for identifying and categorizing events with the following clarifications: a) The staff emphasizes the cautions in NEI 18
-04 that the F
-C target figure does not depict acceptance criteria or actual regulatory limits. The anchor points used for the figure are surrogates for other measures that may be expressed in different units, time scales, or distances. The F
-C target provides a reasonable approach to be used within a broader, integrated approach to determine risk significance and support SSC classification and confirm the adequacy of DID [defense in depth]. b) The F-C target and related discussions in NEI 18
-04 include a frequency of 5x10-7 per plant
-year to define the lower range of beyond design basis events. This demarcation of lowest event frequencies on the F
-C target and category definitions should not be considered a hard and fast cutoff but should instead be considered in the context of other parts of the methodology described in NEI 18
-04. These other considerations include the role of the integrated decision
-making panel, DID assessments, accounting for uncertainties, and assessing for potential cliff-edge effects.
12Working draft DG 1353 FindingsLicensing Basis Eventsc) NEI 18-04 describes a set of DBEHLs that will determine the design basis seismic events and other external events that the safety related SSCs will be required to withstand. When the DBEHLs are determined using NRC
-approved methodologies, this approach is generally consistent with current practices and provides acceptable protection of safety
-related SSCs. When supported by available methods, the PRA model is expected to address the full spectrum of internal events and external hazards that pose challenges to the capabilities of the plant, including external hazard levels exceeding the DBEHLs. The inclusion of external events within the BDBE category supports the overall risk
-informed approach in NEI 18
-04 and the DID assessments described in subsequent sections. NEI 18
-04 states: "When supported by available methods, data, design and site information, and supporting guides and standards, these DBEHLs will be informed by a probabilistic external hazards analysis and included in the PRA after the design features that are included to withstand these hazards are defined." To the degree that applicants propose methods to identify DBEHLs that have not been previously reviewed and approved by the NRC, the staff would review the proposed methodologies on a case
-by-case basis.
13Working draft DG 1353 FindingsLicensing Basis Eventsd) NEI 18-04 describes how the application of a single failure criterion is not deemed to be necessary for non
-LWRs using the methodology because they will employ a diverse combination of inherent, passive, and active design features to perform the required safety functions across layers of defense and will be subjected to an evaluation of DID adequacy. The process described in NEI 18-04 includes assessing event sequences (including reliability and availability of SSCs and combinations of SSCs) over a wide range of frequencies and establishing risk and safety function reliability measures. - The approach described in NEI 18
-04 is consistent with the Commission's SRM approving the recommendation in SECY 0047 to replace the single
-failure criterion with a probabilistic (reliability) criterion. -e) The methodology in NEI 18
-04 includes a potentially expanded role for PRA beyond that currently required by 10 CFR Part 52. The staff's review of the PRA prepared by a designer could be facilitated by the NRC endorsement of consensus codes and standards (e.g., ASME/ANS RA
-S-1.4, "Probabilistic Risk Assessment Standard for Advanced Non
-LWR Nuclear Power Plants") and the use of that approved standard by the designer.
- Staff Position: NEI 18-04 provides an acceptable method for assessing and classifying SSCs as safety related, non
-safety related with special treatment, or non
-safety related with no special treatment. The staff offers the following clarification: a) The SSC classifications and logic outlined in NEI 18
-04 are part of an integrated methodology, which includes a defined relationship between licensing basis events, equipment classification, and assessments of DID. The classifications and related outcomes may not be applicable for alternative approaches that do not follow the other parts of the methodology described in NEI 18-04. 14Working draft DG 1353 FindingsSafety Classification & Performance Criteria
- Staff Position: NEI 18-04 provides an acceptable method for assessing the adequacy of DID to be provided by plant capabilities and programmatic controls, with the following clarifications: a) Section 5.9.6, "Considerations in Documenting Evaluation of Plant Capability and Programmatic DID," discusses change control processes following the issuance of a license, certification, or approval. The staff plans to address such change control processes in future guidance documents and therefore makes no findings on this section of NEI 18
-04. 15Working draft DG 1353 FindingsEvaluation of Defense
-in-Depth Adequacy
- Emergency Preparedness
-- For non-LWRs, the spectrum of events is expected to be the LBEs as described in NEI 18
-04, adjusted as necessary to reflect the specific criteria in the emergency planning decisionmaking process (e.g., dose calculations over 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> from the release of radioactive materials in DG-1350 versus 30 days in NEI 18
-04 for plotting on the F
-C target).
- Mechanistic Source Term
--While not addressed in detail within NEI 18
-04, the development of mechanistic source terms for designs and specific event families is another element of an integrated, risk
-informed, performance
-based approach to designing and licensing non
-LWRs. Applicants are expected to provide in their applications or related reports a description of their mechanistic source terms, including the retention of radionuclides by barriers and the transport of radionuclides for all barriers and pathways to the environs. Where applicable, a facility may have multiple mechanistic source terms and specific event sequences to address various systems that contain significant inventories of radioactive material.
16Working draft DG 1353 FindingsOther Considerations 17Working draft DG 1353 FindingsInforming Content of Applications
- NEI 18-04 provides useful guidance for applicants to identify and provide the appropriate level of information needed to satisfy parts of the regulatory requirements in 10 CFR 50.34, 10 CFR 52.47, 10CFR52.79, 10 CFR 52.137, and 10 CFR 52.157.
- Combination of deterministic evaluations and probabilistic risk assessments
- Information needed on fuel, primary, and other barriers to define limitations, performance characteristics, and as input to mechanistic source term
- Information needed on SSCs and programmatic controls associated with key safety functions
- Scope and depth for other information (e.g., ancillary plant systems) to be determined based safety/risk significance (i.e., roles in preventing or mitigating licensing basis events)*Level of detail can also reflect potential performance
-based approaches (see Introduction, Part 2, to NUREG 0800) 18DG 1353 & Related SECY
- Target Schedule
-ACRS SubcommitteeJune 19, 2018 -Draft NEI 18
-04, DG-1353, SECYSept 28, 2018 (public, to ACRS
)-ACRS SubcommitteeOct 30, 2018 -ACRS Full CommitteeDec 6, 2018
-Issue DG-1353Dec 21, 2018
-Issue SECYearly 2019
-ACRS Interactionsmid 2019-Issue Final RGTBD 2019