ML21271A190
| ML21271A190 | |
| Person / Time | |
|---|---|
| Issue date: | 09/20/2021 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Widmayer, D., ACRS | |
| References | |
| NRC-1681 | |
| Download: ML21271A190 (200) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Future Plant Designs Subcommittee Docket Number:
(n/a)
Location:
teleconference Date:
Monday, September 20, 2021 Work Order No.:
NRC-1681 Pages 1-124 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1716 14th Street, N.W., Suite 200 Washington, D.C. 20009 (202) 234-4433
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1 2
3 DISCLAIMER 4
5 6
UNITED STATES NUCLEAR REGULATORY COMMISSIONS 7
ADVISORY COMMITTEE 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 transcript has not been reviewed, 17 corrected, and edited, and it may contain 18 inaccuracies.
19 20 21 22 23
1 UNITED STATES OF AMERICA 1
NUCLEAR REGULATORY COMMISSION 2
+ + + + +
3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4
(ACRS) 5
+ + + + +
6 FUTURE PLANT DESIGNS SUBCOMMITTEE 7
+ + + + +
8 MONDAY 9
SEPTEMBER 20, 2021 10
+ + + + +
11 The Subcommittee met via Videoconference, 12 at 9:30 a.m. EDT, Dennis Bley, Subcommittee Chair, 13 presiding.
14 COMMITTEE MEMBERS:
15 MATTHEW W. SUNSERI, Chairman 16 JOY L. REMPE, Vice Chairman 17 RONALD G. BALLINGER, Member 18 VICKI M. BIER, Member 19 DENNIS BLEY, Member 20 CHARLES H. BROWN, JR. Member 21 VESNA B. DIMITRIJEVIC, Member 22 GREGORY H. HALNON, Member 23 JOSE MARCH-LEUBA, Member 24 DAVID A. PETTI, Member 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
2 DESIGNATED FEDERAL OFFICIAL:
1 Derek A. Widmayer 2
ALSO PRESENT:
3 Victoria Anderson, NER 4
Keith Compton, RES 5
Karl Fleming, JCNRM 6
Dennis Henneke, JCNRM 9
Hanh Phan, NRR 10 Mehdi Reisi-Fard, RES 11 Marty Stutzke, NRR 12 Shilp Vasavada, NRR 13 Donna Williams, NRR 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
3 P R O C E E D I N G S 1
9:32 a.m.
2 MEMBER BLEY: Good morning, everyone, the 3
meeting will now come to order. This is a meeting of 4
the Advisory Committee on Reactor Safeguards 5
Subcommittee on Future Plant Designs. I'm Dennis 6
Bley, chairing this Subcommittee meeting.
7 ACRS Members in attendance as of the last 8
time I looked are Ron Ballinger, Charlie Brown, Vesna 9
Dmitrijevic, Greg Halnon, Jose March-Leuba, Dave 10 Petty, Joy Rempe, and Matt Sunseri.
11 If anybody else has come on let me know.
12 MEMBER BIER: Dennis, I just joined.
13 MEMBER BLEY: Thank you, Vicki. So, we 14 have almost a full house of members, I don't see Walt 15 yet. He's probably gone, he is gone. Derek Widmayer 16 of the ACRS Staff is the designated federal official 17 for this meeting.
18 The purpose of today's meeting is to 19 discuss the draft regulatory guide 1.247, 20 exceptability of probabilistic risk assessment results 21 for advanced Non-Light Water Reactors risk-informed 22 activities, which says that it endorses with 23 exceptions and clarifications the non-LWR PRA 24 standard, ASME-ANS, RA-S-1.42021.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
4 Actually, the text of the reg guide lists 1
no exceptions, it does list qualifications and 2
clarifications. Before we begin, I want to raise a 3
few issues for the Staff and for Members to consider 4
today.
5 I had anticipated that the Staff would 6
want a letter at this time but after noting that the 7
Reg Guide states that it describes one trial approach 8
and after seeing a very large number of qualifications 9
and clarifications, I wonder if a letter would be more 10 appropriate after revisions to the standard reg guide 11 occurs.
12 The Staff and representatives of the 13 Standards Committee are invited to comment on this 14 question during their presentations.
15 We will poll the Subcommittee near the 16 close of the meeting to determine the Members' 17 opinions on the need for a letter at this time.
18 The reg guide is structured much like Reg 19 Guide 1.200, exceptability of PRA results for 20 risk-informed activities, however, I notice the 21 discussion in Part C that very thoroughly describes an 22 acceptable PRA differs quite a bit from the specific 23 line in Reg Guide 1.200.
24 I would have expected the new reg guide to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
5 refer to 1.200 for most or all of the extensive 1
descriptive information.
2 I'm not sure why it didn't, I'm also not 3
sure why the text is so different and I wonder if the 4
Staff intends to revise 1.200 to match this new 5
language.
6 Maybe the Staff can comment on that when 7
they're giving their presentations as well.
8 Finally, this Committee has written to the 9
Staff on several occasions about the importance of 10 conducting the search for initiating events and 11 associated scenarios for new designs without pre-12 conceptions, using a structured approach to enhance 13 the thermos of the search.
14 Of course, after a list of initiating 15 events is developed, it makes sense to compare it with 16 lists developed for current LWRs and even other 17 industries to look for possible omissions that should 18 be picked up.
19 The current version of the standard does, 20 in my opinion, a nice job of stating the requirements 21 for a
structured search and its supporting 22 requirements, IE-A1, 2, 5, 6, 9, 12, 16 and 17.
23
- Also, the explanatory, non-mandatory 24 Appendix IE provides help on how to conduct the search 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
6 and includes elements that should enhance the rigor of 1
the search, including IE-N-1, 2, 8 to 17, 20, 23 to 2
26, 28, and 32 to 34.
3 It was surprising, at least to me, that 4
the Staff had no clarifications on any of these 5
supporting requirements or explanatory notes. It was 6
rather than disappointing that the Staff had no 7
comments on the importance of starting this search 8
with a blank sheet of paper.
9 When there's ample research demonstrating 10 the study within an existing list creates significant 11 anchoring bias. The temptation is to start with the 12 existing list and remove events that do not apply to 13 the new design.
14 Today the Subcommittee will gather 15 information, analyze relevant issues and facts, and 16 formulate proposed positions and actions as 17 appropriate.
18 This matter is scheduled for our October 19 full Committee meeting at which time the Committee may 20 develop a letter report on the Reg Guide to transmit 21 to the Staff.
22 The ACRS was established by statute and is 23 governed by the Federal Advisory Committee Act, FACA.
24 The NRC implements FACA in accordance with its 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
7 regulations found in Title 10 of the Code of Federal 1
Regulations Part 7.
2 The Committee can only speak to its 3
published letter reports. We hold these meetings to 4
gather information and perform preparatory work that 5
will support our deliberations at a full Committee 6
meeting.
7 The rules for participation in all ACRS 8
meetings including today's were announced in the 9
Federal Register on June 13, 2019.
10 The ACRS Section of the NRC public website 11 provides our charter, bylaws, agendas, letter reports, 12 and full transcripts of all full and Subcommittee 13 meetings including the slides presented at those 14 meetings.
15 The meeting notice and agenda for this 16 meeting were posted there.
17 As stated in the Federal Register notice 18 and in the public meeting notice posted to the 19 website, members of the public who desire to provide 20 written or oral input to the Subcommittee may do so 21 and should contact the designated federal official 22 five days prior to the meeting as practicable.
23 Today's meeting is open to public 24 attendance and we have received one request to make an 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
8 oral statement from the Victoria Anderson at NER.
1 Time has also provided an agenda after the 2
presentations are complete for this oral statement or 3
for spontaneous comments for members of the public 4
attending or listening to our meetings.
5 Today's meeting is being held over 6
Microsoft Teams, which includes a telephone bridge 7
line allowing participation of the public by Teams or 8
by phone.
9 A transcript of today's meeting is being 10 kept, therefore, we request that meeting participants 11 on Teams and the bridge line identify themselves when 12 they speak and to speak with sufficient clarity and 13 volume that they can be readily heard.
14
- Likewise, we request that meeting 15 participants keep their computer and telephone lines 16 on mute when not speaking to minimize disruptions. At 17 this time I ask the Teams attendees make sure they are 18 muted so we can commence the meeting.
19 We will now proceed. I will call on Mehdi 20 Reisi-Fard, Branch Chief of the Performance and 21 Reliability Branch of the Office of Research for 22 opening remarks.
23 Mr. Fard?
24 MR. REISI-FARD: Good morning, was someone 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
9 saying something?
1 MEMBER BLEY: No, go ahead.
2 MR. REISI-FARD: Good morning, my name is 3
Mehdi Reisi-Fard, I'm the Branch Chief of the 4
Performance and Reliability Branch of the Office of 5
Nuclear Regulatory Research.
6 First of all, I want to thank the 7
Committee for the opportunity to present on the draft 8
of reg guide 1.247, which is the guidance and 9
acceptability of PRA results for advanced Non-Light 10 Water Reactors risk-informed activities.
11 As you'll hear today in the Staff 12 presentation, we believe this guidance will be a 13 critical element in applying PRA information and 14 risk-informed approaches in our regulatory activities 15 related to Non-Light Water Reactors.
16 I'll start by highlighting a few points 17 about the driver behind the Non-Light Water Reactors 18 PRA acceptability project.
19 The organization and execution of the 20 Staff's efforts to develop and publish Reg Guide 1.247 21 has been a substantial and unprecedented undertaking 22 given the timeframes the NRC committed to meet.
23 In January of 2019, the nuclear energy 24 innovation and modernization act known as NEMA was 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
10 signed into law, which created a driving force for the 1
NRC to prepare for anticipated new applications for 2
advanced reactors.
3 Prior to NEMA, the Staff had no near-term 4
plans to endorse a consensus standard for Non-Light 5
Water Reactors PRA.
6 However, NEMA accelerated the need for the 7
standard development organizations to publish and for 8
the NRC Staff to endorse the consensus standard for 9
non-LWR PRAs.
10 So, the Staff had to organize and plan for 11 their efforts relatively quickly in anticipation of 12 the publication of the PRA standard.
13 Besides the accelerated schedule, another 14 unique aspect or challenge related to the standard 15 endorsement is that the scope of this standard is 16 broader than any previously considered or endorsed 17 consensus standard for PRA.
18 The scope includes all radiological 19 sources, all hazards, all plant operating states, and 20 all levels of analysis.
21 Because of their relationship between the 22 Non-Light Water Reactors and related Light Water 23 Reactors PRA standards and because the Staff 24 anticipates endorsing the future Light Water Reactors 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
11 PRA standards, the Staff recognized early the need to 1
ensure that the Staff positions on the Non-Light Water 2
Reactors PRA standard would be consistent with 3
anticipated future endorsement.
4 Let me close by saying a few words about 5
the Staff's efforts so far. As I stated earlier, the 6
Staff needed to develop an aggressive schedule to 7
issue this guidance.
8 Staff have achieved key project milestones 9
with little deviation from the overall project 10 schedule and our currently on track to meet the final 11 publication deadline, which is the end of this 12 calendar year.
13 Developing this guidance required 14 extensive coordination across different groups to 15 develop a unified Staff position with a consistent 16 narrative.
17 Given the NRC's completion schedule and 18 the complexity of the project, many of the next steps 19 of the publication process including this briefing are 20 being performed in parallel.
21 As
- such, the Staff will keep 22 decision-makers appraised of any actionable feedback 23 or potential changes the Staff may implement in 24 response to such feedback.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
12 And the internal concurrence review 1
process will be somewhat dynamic. With that, I 2
conclude my opening remarks. We very much appreciate 3
this opportunity today and we look forward to your 4
comments.
5 MEMBER BLEY: Before you turn it to 6
someone else to continue the presentation, to the 7
point I raised in the opening, I was kind of surprised 8
by the sheer number of qualifications and 9
clarifications in the Reg Guide.
10 And I wonder if the standards, people were 11 also surprised, they'll get a chance to speak later.
12 But do you anticipate there will be another round of 13 possible changes to this standard and a reissue of 14 this document?
15 To me most of those were important 16 clarifications but there were no exceptions to the 17 standard. If you can say anything on that it would 18 help, or would you prefer that we just write a letter 19 on the current version as it is?
20 MR. REISI-FARD: I'm sure the Staff will 21 get into more discussion on this but very briefly, and 22 folks from the team can weigh in if needed, there are 23 plans in the future for the JCRM to revise or issue a 24 new revision of the standard.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
13 The current endorsement effort is going to 1
be strictly on what is published so it seems like 2
we're going to move forward with the current version 3
of this standard and the current draft guidance.
4 As I said in the future, there may be some 5
revisions to the standard.
6 MEMBER BLEY: We look forward to hearing 7
what the Staff and Members of the standards group have 8
to say later. I guess that's enough, thank you very 9
much. You can turn it over to your first speaker, if 10 you would.
11 MR. REISI-FARD: Our next speaker is 12 Michelle Gonzalez. Michelle, please take it away.
13 MEMBER BROWN: Dennis, before that starts, 14 this is Charlie, could I ask as a non-PRA expert --
15 MEMBER BLEY: You can ask it as a human 16 being of any sort.
17 MEMBER BROWN: That's precisely how I'm 18 asking it. So, if I'm way off base...Why is the PRA 19 for a Non-Light Water Reactors different from a Light 20 Water Reactor? I thought a PRA was somewhat 21 technology-neutral.
22 MEMBER BLEY: That's addressed to the 23 Staff?
24 MEMBER BROWN: Yes, that's addressed to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
14 the Staff. I saw the stuff you were talking about, 1
Dennis, the clarifications, and I'm just wondering why 2
in the world we even have a different standard for 3
non-LWRs?
4 That's why I wanted to at least ask that 5
and get it out of the way early.
6 MEMBER BLEY: Let's return to this toward 7
the end if the presentations don't address it to your 8
satisfaction.
9 MEMBER BROWN: That's fine.
10 MEMBER BLEY: Anybody else, Members? With 11 this, we'll turn it over Michelle Gonzalez. Michelle?
12 MS. GONZALEZ: Good morning, Dr. Bley, 13 I'll take a first shot on that question and I know the 14 rest of the presenters will go into more into that.
15 But one of the main differences of this 16 standard that it covers all operating phases so there 17 is pretty much a good distinction in the requirements.
18 For pre-operational phases, operational 19 phases, that's one of the main differences on why we 20 would need a different reg guide and a different 21 standard for the advanced NLWR fleet.
22 MEMBER BROWN: So, operational phases mean 23 not just operation but decommissioning as well as 24 building or maintenance or what? I guess I didn't 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
15 realize existing PRAs weren't as far-reaching based on 1
all the meetings I've been participating in.
2 MS. GONZALEZ: Reg Guide 1.200, which is 3
for the LWR cover-only operational phases, and I'm 4
sorry to defer this, Anders, if you could provide 5
additional guidance on this --
6 MEMBER BROWN: That's fine, I was just 7
curious. Thank you, I appreciate it.
8 MS. GONZALEZ: You're welcome. So, I will 9
start off with my presentation. Donna, if you can 10 just slide one back -- yes, that one.
11 So, good morning, I am Michelle Gonzalez, 12 I am a risk and reliability analyst from the office of 13 regulatory research, Division of risk analysis and I'm 14 one of the research technical leads on the development 15 of the reg guide.
16 The way that this briefing is going to be 17 organized, I'll first go over some of the background 18 information providing some updates since our last 19 briefing the last year.
20 Then Anders Gilbertson will discuss the 21 approach of developing Reg Guide 1.247, providing a 22 discussion on the approach of this reg guide versus Re 23 Guide 1.200.
24 Hanh Phan and Marty Stutzke, both from 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
16 NRR, will discuss the scope of reg guide and the staff 1
position, discussing some of the most important issues 2
that were identified for endorsement.
3 The JCNR representatives, Dennis Henneke, 4
Karl Fleming, will provide their feedback on Reg Guide 5
1.247 and will discuss future plans for the non-LWR 6
PRA standard.
7 So, then Donna Williams, she's the Project 8
Manager from NRR, she will close out the briefing with 9
a brief discussion on the next steps of finalizing Reg 10 Guide 1.247 and the upcoming plans for stakeholder 11 engagement.
12 Next slide, please, Donna.
13 MEMBER BLEY: Could you tell us what slide 14 number you're on since it's not showing up on the 15 screen?
16 MS. GONZALEZ: Slide 4.
17 MEMBER BLEY: Thank you.
18 MS. GONZALEZ: The advanced non-LWR PRA 19 standard was initially issued by ASME in 2013 as the 20 trial use standard. Lessons learned from the bylaw 21 applications were used to improve the standard, which 22 was initially validated in May of 2020.
23 The NRC was involved in the validating 24 process, reviewing the standard and providing comments 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
17 to the JCNRM at that point.
1 MEMBER BLEY: Michelle? This was issued, 2
as you say, eight years ago for trial use and I think 3
it's had some trial use. Why is the current reg guide 4
still a trial use reg guide?
5 MS. GONZALEZ: I will discuss it a little 6
bit further but we were discussing different options 7
on how we could endorse these standards in order to 8
meet the deadlines that we needed for upcoming 9
licensees and that part.
10 So, once of the ways we could do this and 11 in order to be able to -- I guess, in the next couple 12 of years we issued it now as a trial reg guide and we 13 can include other things if the JCNRM decide that 14 they're going to be updating the standard.
15 We can include Part 53, things are ongoing 16 now and we will issue a final reg guide in the next 17 couple of years.
18 In February of 2021, the final version of 19 the standard was released and it is important to note 20 here, and I know that Maricova did, but this standard 21 is very unique.
22 It is meant to be technology-inclusive, 23 it covers all levels of analysis from initiating 24 events to radiological consequences. It covers all 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
18 hazards, internal and external, and all operating 1
modes except for low-PRA shutdown types of POSs for 2
internal fire.
3 MEMBER BLEY: Can I interrupt you again?
4 I'm sorry, this is for Charlie. Charlie, what 5
happened with the LWR standard is it came out 6
piecemeal.
7 First, there was the one for operations at 8
power and there have been for internal events that 9
power, then there have been new ones kicked out for 10 external events and for shutdown conditions and 11 others.
12 So, the current one we're looking at today 13 is trying to do all that in one package and I think 14 that's correct. Michelle, go ahead.
15 MEMBER BROWN: Thank you, Dennis.
16 MS. GONZALEZ: It also covers elements 17 that have not been endorsed yet by any other reg 18 guides. Some of this is the element for risk 19 integration and mechanistic source terms.
20 For these new elements, we're basically 21 just setting up the stage for future plans for 22 endorsements on our part.
23 So, also, the technical requirements in 24 the standard apply to different licensing phases from 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
19 the design, pre-operational, and operational phases.
1 Slide 5, please.
2 MEMBER BALLINGER: This is Ron. I'm 3
following the talk with the slides that were sent out 4
by email but I don't see slides on your screen.
5 MEMBER BLEY: I think just follow the 6
other ones if you can, Ron. Four or five of us can't 7
see it, the rest of us see it just fine. I think 8
we're going to fix that on the fly.
9 MEMBER BROWN: I don't see them either, 10 Dennis, so I'm one of the non-viewers.
11 MEMBER BALLINGER: I got that, Charlie.
12 MS. GONZALEZ: For your reference, I'm on 13 Slide 5 now. So, we met last year with the ACRS on 14 this topic on November 2nd. In that briefing we 15 talked about the NRC endorsement plans and provided a 16 summary of the valid results.
17 There has been a lot of progress since 18 that briefing. In January the Staff issued a draft 19 white paper to provide NRC views and perspectives on 20 the non-LWR PRA standard.
21 This paper is publicly available and can 22 be accessed in ADAMS with the number that's referenced 23 here.
24 I will go into more details on the paper 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
20 in the next slide. Also, during the course of the 1
year, we have several interactions with NEI where we 2
were able to provide some comments on NEI 2009, which 3
is in the PRA review guidance for non-LWRs.
4 Following those interactions, the NRC 5
received an updated version of NEI 2009 in May of 6
2021. The previous issue and prior use reg guide, Reg 7
Guide 1.247, was made publicly available on September 8
7th and I just want to note here that this is the same 9
version that we sent out to the ACRS.
10 This vision was sent to them for review 11 and the review was completed, this was Friday. So, we 12 know this version has some internal issues, typos, and 13 formatting things that will be fixed now that we have 14 the QT revised version back.
15 Slide 6, as I mentioned on the previous 16 slide, the steps of the draft white paper, the title 17 is Demonstrating the Acceptability of Pra Results Used 18 to Support Advanced Non-LWR Plan Licensing.
19 The main purpose of this paper was to 20 provide early feedback on the staff views and 21 perspectives on the non-LWR PRA standard.
22 This was done as a way of facilitating 23 early communications with stakeholders on the issues 24 that would be addressed in Reg Guide 1.247, allowing 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
21 for some additional opportunities for the public to 1
provide feedback to the NRC on these issues.
2 We held a public meeting on February 23rd 3
to discuss the white paper and received some feedback 4
from the industry and from NEI so the comments that we 5
received in that interaction were considered during 6
the development of the trial use reg guide.
7 After various discuss, the Staff agreed 8
that some of the issues that were identified in the 9
white paper would be better addressed separately in 10 other Staff guidance, like for instance, ISGs or some 11 of the issues were require additional work or research 12 we completed.
13 And I know that Marty will provide 14 additional details on these issues later on in his 15 presentation. Slide 7, please. So, in our last 16 briefing to ACRS, we were still discussing the options 17 for endorsement of the standard.
18 After previous interactions with 19 management and OGC, the Staff agreed that endorsing 20 the standard with a trial use reg guide would be the 21 best option going forward.
22 And as I was trying to explain earlier on, 23 this option allows the NRC to incorporate lessons 24 learned during the trial use period and will also 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
22 allow us to account for regulatory activities like the 1
Part 53.
2 We're also taking into account that the 3
standard might be revised at some point in the next 4
few years so we would also be able to address any 5
changes in the standard in the final reg guide.
6 Even though there will not be a public 7
comment period for the trial use reg guide, the reg 8
guide is publicly available so we encourage you to 9
provide comments to the NRC.
10 We will take into account both the lessons 11 learned from the trial use and comments received 12 during that period. This will be considered in the 13 final version of the reg guide.
14 There will be a formal comment period 15 after the trial use period has been completed and the 16 formal draft guide is issued.
17 So, in terms of the peer review guidance, 18 the Staff found that the guidance provided in NEI 2009 19 was acceptable
- and, therefore, there were no 20 exceptions taken for endorsement of NEI 2009.
21 So, that completes my presentation, if 22 there are no further questions, I will turn it over to 23 the next speaker, which is Anders Gilbertson.
24 MEMBER BLEY: Before you go, Michelle, on 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
23 your last slide, those times when you expect to have 1
a revised final guide and put it out for public 2
comment, do you have any rough dates on when you 3
expect that to happen?
4 MS. GONZALEZ: We haven't finalized that 5
date yet, we've been speaking about 18 months so maybe 6
3 years where we are expecting to have the trial use 7
period completed and then we would go over the process 8
to develop as a draft guide.
9 MEMBER BLEY: Have you gotten any 10 indications from potential Applicants or vendors about 11 further expected trial use in the next year or so?
12 MS. GONZALEZ: Not exactly.
13 MEMBER BLEY: Thank you.
14 MS. GONZALEZ: You're welcome.
15 MR. PHAN: Anders?
16 MR. GILBERTSON: Yes?
17 MR. PHAN: Good morning, my name is Hanh 18 Phan, one of the presenters in this briefing.
19 I'd like to mention that first I did not 20 see the slides on the screen but after I hit the show 21 conversation option and then I re-hit that one, the 22 slide came up.
23 So, you may try that, it may help you to 24 see the slides on the screen.
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24 MEMBER BLEY: Thank you, everybody can try 1
that and I just thought in the last couple iterations 2
of this software, once in a while if you do something 3
on your screen the slides might jump down on the lower 4
bottom and be down there and you have to click on them 5
to get them back on your main screen.
6 So, take a look at that bar at the bottom 7
as well as what Hanh just suggested.
8 MR. GILBERTSON: Good morning, Members of 9
the ACRS Subcommittee, my name is Anders Gilbertson, 10 I am a reliability and risk analyst in the Office of 11 Nuclear Regulatory Research.
12 And before I get started, Dr. Bley, I just 13 wanted to also follow on Michelle's response to your 14 question about the timeframes.
15 At the moment, we're anticipating that we 16 may be somewhat dependent on the schedules of the 17 standards development organization, so the JCNRM, in 18 terms of when they anticipate producing a subsequent 19 revision and that there have been enough lessons 20 learned.
21 So, the whole notion of 12, 18, 24 months, 22 it's very rough but really, it's going to primarily 23 depend on whether or not we have enough lessons 24 learned.
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25 MEMBER BLEY: Sure, and maybe they'll want 1
to say something when they come up later today. Go 2
ahead.
3 MR. GILBERTSON: Can you move to Slide 9, 4
please? There are four main topics that I'm going to 5
address this morning.
6 First, I'm going to talk about the 7
regulatory paradigm that Reg Guide 1.247 addresses.
8 I'll then talk about how the Staff approached the 9
development of the reg guide to reflect that paradigm.
10 And because Reg Guide 1.200 was the 11 starting point for Reg Guide for 1.247, even before I 12 get into the more detailed comparison in that third 13 bullet, I will naturally be drawing some higher-level 14 comparisons between the two reg guides all the way 15 just because it falls out naturally from the 16 discussion.
17 And then finally, I will talk about some 18 of the new Staff positions in Reg Guide 1.247 had been 19 previously addressed as it relates to peer 20 acceptability.
21 And I think as we go forward, I may end up 22 addressing some of the questions that were previously 23 asked by the ACRS Subcommittee Members.
24 So, with that, please move to Slide 10.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
26 So, regarding the regulatory paradigm that Reg Guide 1
1.247 is meant to operate in, Reg Guide 1.247 is not 2
specifically intended to meet any one regulatory 3
requirement.
4 So, for many reg guides, their purpose is 5
to provide an acceptable means of meeting a specific 6
regulatory requirement.
7 Now, like Reg Guide 1.200, Reg Guide 1.247 8
is used to determine the acceptability of a PRA that's 9
used to support a regulatory decision but there are 10 some differences, as I'll go into.
11 At the moment, the application of Reg 12 Guide 1.247 includes applications for non-LWRs under 13 Parts 50 or 52 and for Part 52, a PRA is currently 14 required. Part 50 is expected to soon follow after 15 the completion of the related rulemaking.
16 That's intended to align the two parts.
17 Section A of Reg Guide 1.247 provides a listing of 18 applicable regulations for which an Applicant may use 19 the reg guide to support meeting.
20 Michelle touched on this a little bit but 21 as we look forward, we anticipate that Reg Guide 1.247 22 will be applicable to the anticipated 10 CFR Part 53 23 once that rulemaking is complete.
24 However, up until that point, the Reg 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
27 Guide 1.247 only addresses current published 1
regulations and does not provide any Staff positions 2
on the anticipated 10 CFR Part 53 or other future 3
activities.
4 MEMBER BLEY: Anders, this is an unfair 5
question but it hit me out of the blue last week. The 6
industry released an announcement, I think it was an 7
ANS one, that the Staff position paper on how to deal 8
with micro-reactors was out and they had a link to it.
9 My understanding is that's really pretty 10 early in the process for you. It's not an approved 11 position paper and eventually, I assume we'll hear 12 about it.
13 But if you can say anything about how that 14 ties in with this work and with the Part 53 work just 15 to give us a heads-up, that would be interesting. If 16 you can't, that's fine too.
17 MR. GILBERTSON: I can generally speak to 18 it. Marty Stutzke is certainly far more familiar with 19 it as he's been involved in some of these peripheral 20 efforts.
21 But it's a good question because it kind 22 of helps point out that Reg Guide 1.247 does have many 23 connection points to other NRC activities.
24 So, as you're asking about, the initiative 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
28 for graded PRA is being considered which I think 1
micro-reactors falls under that and do you need to do 2
a full-blown PRA for a micro-reactor? That kind of 3
thing.
4 So, yes, there are connection points.
5 Like I said, Marty's been involved in a lot of those 6
activities. Also, the guidance for developing the 7
content of applications, the TICAP and the ARCAP 8
efforts.
9 So, I'll leave it there and Marty, if you 10 want to chime in please feel free to go ahead.
11 Otherwise, I'm happy to see if that satisfies it for 12 now.
13 MR. STUTZKE: Yes, this is Marty Stutzke 14 with NRR. What I would add is in addition to the 15 micro-reactor draft staff white paper, I'm personally 16 involved in the Part 53 rulemaking team and the graded 17 PRA initiative.
18 And the TICAP, ARCAP development guidance.
19 So, we're reasonably well coordinated among all these 20 things and we're trying to develop Reg Guide 1.2747 to 21 address all of these activities.
22 MEMBER REMPE: This is Joy and to follow 23 Dennis's question, one of the reasons this standard is 24 all inclusive might be that you've got to consider all 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
29 the hazards associated at the site, including the 1
spent fuel.
2 And so with the thing about micro-3 reactors, how will a PRA deal with that where this is 4
the potential when you don't have a place to send them 5
back to, you could accumulate a lot of spent micro-6 reactors.
7 Is that being considered? You don't have 8
to analyze it but just say you need to consider this 9
as a hazard source.
10 MR. STUTZKE: I'll answer that. In 11 general, what Reg Guide 1.247 requires is that the PRA 12 address all radiological sources at the site, all 13 plant operating modes at power shutdown 14 configurations, and all internal and external hazards.
15 So, we think we're comprehensive.
16 MEMBER REMPE: So, you've told them they 17 need to do that, is what the answer to my question is?
18 MR. STUTZKE: Yes.
19 MEMBER REMPE: Even though you don't give 20 them much guidance on how to do it, they should 21 clearly know they're going to have deal with that?
22 And that includes when you said how big the site 23 boundary should be, right?
24 MR. STUTZKE: Yes.
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30 MEMBER REMPE: Thank you.
1 MEMBER BLEY: Let me take you a little 2
further, you probably don't want to talk about it but 3
it relates to Charlie's question.
4 I could see how this could become the PRA 5
standard and we wouldn't need all the pieces that were 6
developed throughout the LWR development process for 7
PRA.
8 This might tie everything together here 9
and there could one day be a single standard for PRA 10 for all nuclear power-plants. Is that the idea, 11 working this way around or is that something you might 12 see in the next two to five years?
13 MR. GILBERTSON: I can address that. Yes, 14 that is a notion that has been talked about. If you 15 look at the non-LWR PRA standard, in theory there 16 isn't really any reason why you couldn't use that 17 standard to perform a PRA for an LWR.
18 MEMBER BLEY: I certainly agree with you.
19 MR. GILBERTSON: And that was under the 20 guise of being technology inclusive. This Reg Guide 21 1.247 really is in many regards something of an 22 evolution of the way NRC is addressing PRA 23 acceptability.
24 We recognize that because of it's 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
31 completeness, we will have to consider it heavily when 1
we are sitting down to develop the next technical 2
revision of Reg Guide 1.200 for LWRs.
3 And I think it's certainly conceivable 4
that perhaps in the end, we end up having one reg 5
guide. That's just my opinion, I'm not speaking to 6
whatever plans the Staff have but it's certainly 7
possible.
8 MEMBER BLEY: Thank you, that makes sense 9
to me and would explain how the language has evolved 10 from 1200 and the same language then would apply to 11 everyone.
12 Marty was talking about what he called the 13 initiative for graded PRA and I really look forward to 14 hearing more about that at some point in the future.
15 Is there conversation with the standards 16 folks? Are they likely to issue a standard in that 17 same area or will this strictly be an NRC initiative?
18 We'll hear from them later, if they want to talk about 19 that it's a heads-up to them.
20 MR. GILBERTSON: I can't speak for them 21 and as far as the NRC is concerned, I would just point 22 to our efforts for looking at graded PRA.
23 I think it's going to evolve as we 24 continue to develop, continue to understand the needs 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
32 of industry and what we need to do to help ensure 1
we're meeting the mission.
2 MEMBER BLEY: Thanks very much, go ahead.
3 MEMBER DIMITRIJEVIC: I have a slightly 4
different question. Can you elaborate a little more 5
on this second bullet on what says the use of this reg 6
guide addresses the needs for in-depth review of the 7
PRA?
8 What does that imply?
9 MR. GILBERTSON: Actually, I was just 10 about to get to that. Let me just go ahead and jump 11 right into it. Reg Guide 1.247, the way this was 12 developed was that it helps to reduce the need for an 13 in-depth review of the PRA.
14 And I emphasize the word reduce, as you're 15 questioning about, because it's different from Reg 16 Guide 1.200, which relates to obviating the need. So, 17 the term reduce relates in part to the different scope 18 of regulatory activities addressed between the two reg 19 guides.
20 Reg Guide 1.247 is addressing the initial 21 licensing activities such as submittal of design 22 certifications, permits, license requests, and it also 23 addresses risk-informed regulatory activities 24 following the issuance of a license permit or 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
33 certification.
1 So, it communicates the Staff have a 2
little more latitude in requesting information about 3
an Applicant's PRA.
4 And so in general, Reg Guide 1.247, and 5
I'll talk about this a little bit more, it still has 6
the same type of framework, paradigm as 1.200 where 7
the approach is to develop your PRA as endorsed by an 8
NRC consensus standard and then perform an NRC 9
endorsed peer review process.
10 That helps to the Staff gain confidence 11 that the PRA is acceptable for use in risk-informed 12 decision-making, however, the reg guide is just 13 guidance, Applicants don't have to use it, there are 14 no requirements to used Reg Guide 1.247.
15 Does that help address your question?
16 MEMBER DIMITRIJEVIC: It makes me slightly 17 less confused but let's say you have Applicants with 18 design certifications and your use of these guides 19 would not be required.
20 Let's say the Applicant has been reviewed 21 before the applications. Would the peer review 22 process of design certification be different from that 23 Applicant who has a peer review already performed?
24 MR. GILBERTSON: Are you're saying they 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
34 are peer reviewing not against an NRC-endorsed 1
consensus standard?
2 MEMBER DIMITRIJEVIC:
No, they're 3
reviewing this process, the NEI which is endorsing 4
1.247.
5 MR. GILBERTSON: I guess what I would say 6
to that is if an Applicant chooses to use a portion of 7
this reg guide, then certainly the Staff may need to 8
ask additional information to help gain that 9
confidence.
10 So, for example, if an Applicant performs 11 their PRA and develops it, they perform an internal 12 self-assessment and then they feel they're ready to 13 submit, they don't do an independent peer review but 14 they say, look, we met the Staff positions in Reg 15 Guide 1.247 as it relates to the consensus PRA 16 standard.
17 So, because the peer review wasn't 18 performed, there's still a need for the Staff to 19 determine in some manner that the PRA is in fact 20 acceptable, as dictated by the self-assessment and 21 also by our own questions and reviews.
22 So, that would be a case where there could 23 be a more in-depth review, which again, this is why 24 using Reg Guide 1.247 helps reduce the need for that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
35 in-depth review.
1 But because this is in the context of the 2
initial licensing activities and you have requirements 3
to develop a PRA, describe it in the final safety 4
analysis report, it's a little bit different than 5
receiving a license amendment request for a 5069 6
program or risk-informed tech specs using Reg Guide 7
1.200.
8 That process has been established as you 9
perform the PRA for the PRA standard, you do the peer 10 review and then if there are issues that raise above 11 a certain threshold, namely a finding level and 12 observation, those get reported to the NRC.
13 But the licensee is not submitting the 14 entire PRA.
15 MEMBER DIMITRIJEVIC: That's exactly the 16 difference which I was confused about.
17 I'm all for risk-informed applications, 18 you don't have to submit that and the full PRA, if you 19 have PRA peer review perform, that's different when it 20 comes to supplying PRA for design certifications, for 21 example.
22 I'm still confused about that but I think 23 somewhere that will all be clear so thank you.
24 MR. GILBERTSON: I think another bullet or 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
36 two later on might help to clarify that.
1 MEMBER BIER: If I could interrupt 2
briefly, this is Vicki Bier, just to clarify the 3
response to Vesna's statement, when you said the level 4
of Staff review could be reduced, that's presumably at 5
the discretion of Staff?
6 If they see issues they consider to be red 7
flags or need going into, they have the option to do 8
that but not an obligation to do that, is that 9
correct?
10 MR. GILBERTSON: Generally, yes, and of 11 course, if the Staff are intending to ask for more 12 detailed information specifically about the PRA, there 13 is still a need to develop a regulatory basis for 14 asking that information.
15 So, in that regard, this notion that the 16 Staff have more latitude is really something of a 17 statement that developing that regulatory basis is a 18 little more straightforward or it's not that difficult 19 to put together, generally speaking.
20 MEMBER BIER: Thank you.
21 MR. GILBERTSON: You're welcome. I will 22 go ahead and move on if there are no questions. So, 23 the last point here that I wanted to talk about, Reg 24 Guide 1.200 uses the term application and it's mostly 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
37 referring to voluntary regulatory activities occurring 1
after the issuance of a license.
2 So, like I mentioned, a license amendment 3
request for 50.69 or some other risk-informed program.
4 It is also meant to address regulatory applications 5
related to standard design certifications and combined 6
licenses.
7 It's just Reg Guide 1.200 hasn't been used 8
to that effect since it was published. But because 9
the range of potential regulatory activities for non-10 LWRs that Reg Guide 1.247 may be used for is broader.
11 The term application in Reg Guide 1.247 12 mostly refers to both the initial licensing regulatory 13 activities and the risk-informed regulatory activities 14 following the issuance of a license certification or 15 permit.
16 And yes, that is that point. Can you move 17 to Slide 11, please? So, there is no regulatory 18 requirement for the performance of a peer review for 19 a PRA used in risk-informed decision-making.
20 However, experience with the use of Reg 21 Guide 1.200 has demonstrated that there are clear, 22 tangible benefits from the performance of an 23 independent peer review.
24 So, while it remains true there are no 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
38 requirements, the Staff are encouraging that a user of 1
Reg Guide 1.247 perform a peer review because it so 2
helps with gaining that confidence that the Staff need 3
to make their decision.
4 It just helps to improve the efficiency of 5
Staff reviews as well. So, as I mentioned before, PRA 6
is required for new Part 52, applications, which 7
again, Part 50 is soon to follow after the related 8
alignment rulemaking is complete.
9 And application required by regulation to 10 develop, maintain, and upgrade -- I'm sorry, an 11 Applicant is required to develop, maintain, and 12 upgrade a PRA as per 10 CFR 50.71 Hotel, which 13 incidentally references Part 52.
14 There are also regulatory requirements 15 related to the use of plant-specific PRA information, 16 for example, 10 CFR 52.79.
17 Now, because a PRA is used to help develop 18 and support the licensing basis for a given 19 application, I mentioned this before, this is the 20 notion that Staff have more latitude to request 21 information than they would, for example, for a 22 risk-informed license amendment request using Reg 23 Guide 1.200.
24 So, like I said, for Reg Guide 1.200, the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
39 guidance in that document relates to performing an 1
independent peer review to ensure the PRA meets the 2
NRC-endorsed consensus standard, and if issues rise 3
above a certain threshold, those issues and the 4
results of the peer review are submitted to the Staff 5
for review.
6 And so in that regard, sometimes it's not 7
as straightforward for the Staff to develop a 8
regulatory basis that might allow them to say look at 9
a specific part of a licensee's PRA.
10 And again, that's going to be different 11 for new Applicants, non-LWR Applicants, using Reg 12 Guide 1.247.
13 MEMBER HALNON: Anders, this is Greg. Why 14 is soft approach to the peer review? Why not make it 15 a little bit more stringent in saying peer reviews are 16 not only recommended but a key part of the process 17 itself and make it more stringent?
18 MR. GILBERTSON: I think it's in some part 19 because of the framework that we're operating in. Reg 20 Guide 1.200, there is no requirement for an operating 21 licensee with a Part 50 license to use a PRA.
22 So, all of those activities are voluntary 23 activities. For 1.247, we're in this situation where, 24 again, a PRA is required as part of the final safety 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
40 analysis report and to establish the licensing basis 1
for the plant.
2 So, in that regard, it is clearly 3
important but I think we have a different -- I'm 4
trying to think of the history of the development of 5
Reg Guide 1.200 and like Dr. Bley mentioned before, 6
it's been done in some regards in piecemeal fashion.
7 The most important risk readers were 8
developed first and those were put forward in the 9
standard and such.
10 And the Staff, as they considered how the 11 PRAs might be used, they recognized there was a need 12 to ensure the PRA is actually doing what it's supposed 13 to do, it works the way it's supposed to work and has 14 all the right information, et cetera.
15 So, that's what motivated that peer 16 review.
17 In the end, I guess I would probably go 18 back to the idea that there is no requirement for 19 performing a peer review.
20 However, if a peer review is not provided 21 and, for example, an Applicant just submits their PRA 22 and says we think this is good enough, the Staff are 23 going to have to look at that and we have to make that 24 assessment.
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41 Is it acceptable? Does it meet the Staff 1
positions? Did it really meet the requirements they 2
indicated it met in the consensus standard?
3 MEMBER HALNON: I guess the question now 4
when you say that, is there a crossroads in the 5
- guidance, the Staff
- guidance, on reviewing 6
applications and whatnot that say go this path if the 7
peer review was done?
8 If not, go this other path that asks those 9
questions?
10 Because it seemed like those questions 11 would be asked in either case.
12 MR. GILBERTSON: I think to the extent the 13 reg guide does address that, I think it's probably at 14 a very high level and just to convey that if you're 15 not using part of Reg Guide 1.247, then effectively, 16 you're in this situation where the NRC are performing 17 an ad hoc review.
18 And we have to judge it on a case-by-case 19 basis.
20 MEMBER HALNON: Thanks, I'll keep that in 21 mind as we go through the rest of it.
22 MR. GILBERTSON: Slide 12, please? I 23 mentioned this before, Reg Guide 1.200 Revision 3 24 effectively was the template for the development of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
42 Reg Guide 1.247.
1 Some reorganization of the information has 2
occurred, as you're probably aware, however, the key 3
elements of Reg Guide 1.247 mimic that of Reg Guide 4
1.200.
5 So, essentially, we wanted to maintain the 6
overall framework that these reg guides operate in.
7 So, for example, just a brief example, the Staff 8
position in Section C.1 is organized by scope, level 9
of detail, conformance to PRA standards, and plant 10 representation in Reg Guide 1.247.
11 Reg Guide 1.200 for whatever reason, it 12 swapped level of detail and conformance of PRA 13 standards. But the substance of those pieces are 14 ostensibly mimicked in Reg Guide 1.247.
15 So, as a regulatory body, the NRC needs to 16 ensure consistency of related Staff positions, 17 particularly in technical areas where a position is 18 technology-neutral.
19 So, the Staff in that regard need to be 20 sensitive to the fact that Staff positions in Reg 21 Guide 1.247 might set a precedent for revising related 22 Staff positions on PRA acceptability for LWRs.
23 And particularly, where those Staff 24 positions are technology-neutral. And so like I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
43 mentioned before, this is one of the areas where we 1
are going to be looking very closely at Reg Guide 2
1.247 when we start and start laying out and planning 3
and developing the structure of the next technical 4
revision to Reg Guide 1.200.
5 We don't anticipate that it will be 6
significantly different and significantly reorganized 7
but certainly as we've been developing Reg Guide 1.247 8
we've been keeping in mind this idea that we're going 9
to be then doing Reg Guide 1.200.
10 And so we have tried to institute changes 11 in the way we write thing in a way that we would want 12 to do it in Reg Guide 1.200.
13 And I think we've already talk about the 14 fact that NEMA has provided significant impetus to 15 both industry and the NRC to complete a non-LWR PRA 16 standard and endorse it respectively.
17 So, as far as the history is concerned, 18 the Light Water Reactor PRA standards were developed 19 first and for several years, more than a decade or so, 20 the standards development organizations really focused 21 on light water reactors because those were the 22 applications that were relevant at the time.
23 I think it was around about 2009, someone 24 from the JCNR can correct me, when the efforts were 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
44 initiated to develop the non-LWR PRA standard, which 1
again led up to the 2013 trial use non-LWR PRA 2
standard, and subsequently where we are today.
3 So, because the ASME ANS non-LWR PRA 4
standard has been developed to derive and largely 5
mimic what has already been tested and tried out in 6
7 So, in that regard, the non-LWR PRA 8
standard and the LWR PRA standards that are under 9
development currently are very closely related.
10 And because the NRC has previously 11 promulgated Staff positions on LWR PRA acceptability 12 in Reg Guide 1.200, these two things together create 13 a crucial need to ensure the Staff are coordinating 14 the positions across the different technologies as it 15 relates to PRA acceptability.
16 Dr. Bley, this goes to that notion that 17 in the future it's possible that there could just be 18 one PRA standard and that just covers everything and 19 there could be one reg guide that endorses the entire 20 scope.
21 So, in developing positions, the Staff 22 needed to consider what the anticipated Staff 23 positions might be for future endorsements of the new 24 LWR PRA standards that are currently under 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
45 development.
1 And we've already talked about the notion 2
that the non-LWR standard could in theory be used for 3
LWRs, even though its primary focus is for non-LWRs.
4 Slide 13, please? With the understanding 5
of the non-LWRs and the related to LWR PRA standards 6
are very intimately connected with several hundreds of 7
relationships between related requirements.
8 The Staff identified the need pretty early 9
on to systematically identify and objectively compare 10 related requirements between different documents in 11 anticipation of future endorsements of the LWR PRA 12 consensus standards.
13 So, this mapping and comparison effort 14 really helped to orient the Staff, the review of the 15 Staff, with respect to where related requirements were 16 effectively technology-neutral.
17 And it helped us prioritize the 18 development of those Staff positions.
19 So, for example, the ones that needed the 20 most attention and the ones in particular, that 21 relates to requirements that are related between 22 non-LWR and LWR but they're different in the non-LWRs 23 for some specific reason.
24 It may have to do with the technology or 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
46 it may have to do with the question the non-LWR PRA 1
standard was developed and that it considers all scope 2
iteDr.
3 In addition to allowing comparisons 4
between multiple-related PRA standards, the Staff had 5
developed a database to do this activities, to do this 6
mapping and comparison.
7 And we had a
contractor go and 8
systematically identify related requirements, do the 9
comparisons, and then provided those to the Staff.
10 In addition to allowing comparisons 11 between multiple-related PRA standards, the database 12 tools allowed also for comparison against the Staff 13 position in Reg Guide 1.200.
14 So, that is to say that the Staff were 15 interested in looking at the requirements in the non-16 LWR PRA standard, connecting them back through the 17 relevant documents related to LWR and then connecting 18 that back to the Staff position in Reg Guide 1.200 on 19 LWR PRA acceptability.
20 And what that essentially means is the 21 Staff endorsement of the 2009 Level 1 LERF LWR PRA 22 standard. So, it's somewhat convoluted but it's a 23 complex kind of exercise to tie it back.
24 But really, it was intended to just ensure 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
47 that, okay, as we write our Staff position now for 1
non-LWR PRA standards, we aren't being inconsistent 2
with something we wrote in Reg Guide 1.200, where it 3
would be appropriate to be consistent, so technology-4 neutral requirements.
5 MEMBER DIMITRIJEVIC: I just want to point 6
out when you compare that requirement to requirement 7
I'm sure they will not find there are too many 8
differences. But there is a difference in the 9
high-level requirement and the scope.
10 This standard requires Level 3 PRA which 11 didn't require, there is this risk integration which 12 we also discussed in the one, there are source terms.
13 So, there is a difference in the scope and 14 level of requirement and the question is why is that?
15 Why is there a difference in the scope which is not 16 given by the technology differences?
17 MR. GILBERTSON: Yes, so I think the most 18 direct answer to that question is that Reg Guide 1.247 19 was developed with a very strong attention to our 20 understanding that we expect to receive applications 21 using the Licensing Modernization Project, or LMP, if 22 you will.
23 And so if an Applicant uses LMP, what that 24 effectively means is that they necessarily need to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
48 develop a PRA that goes all the way out from an 1
initiator all the way out to consequence and 2
frequency.
3 Because that's the metric against which 4
the risk is measured in the LMP guidance and NRC have 5
endorsed that. So, because we understand those types 6
of applications will be coming in, we had to be sure 7
that we are being comprehensive in our Staff 8
positions.
9 And so like you said, we've got Level 3 10 now, the consequence analysis, we're addressing all 11 plant operating states for all hazards, that kind of 12 thing. We want it to be complete so that we can 13 accommodate those applications.
14 I'll talk a little bit more about those 15 new Staff positions and what some of the limitations 16 are on those. Can we move on to Slide 14, please?
17 I will run through this a little quickly, 18 I think I'm starting to maybe go over my time here.
19 The next few slides are really just to talk about and 20 give you some general differences between Reg Guide 21 1.247 and 1.200.
22 And I mentioned some of these points 23 before so Reg Guide 1.200, it directly relates to 24 meeting regulations. So, an Applicant may use it to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
49 establish PRA acceptability for the PRA they submit 1
with their standard design certification with their 2
combined license, whatever the case may be.
3 Reg Guide 1.247 does provide Staff 4
positions that are different from 1.200 as you've 5
noticed.
6 I will talk about those a little bit later 7
on and Reg Guide 1.247, as far as relatively risk 8
significance criteria are concerned, the reg guide 9
communicates that they should be used to develop the 10 PRA.
11 However, the use of absolutely or relative 12 risk significance criteria in an application will 13 generally be application-specific so it may be that 14 some applications only use absolutely risk 15 significance to determine what are the most important 16 aspects of the risk for an application.
17 Slide 15, please. Some additional 18 differences, the non-LWR standard presents PRA 19 requirements with respect to a more comprehensive 20 scope.
21 We've talked about that, it covers all 22 sorts of radioactivity, all hazards, all plant 23 operating states, and all levels of analysis.
24 And while the non-LWR PRA standard does 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
50 accommodate the development of intermediate risk 1
metrics, for example, something like an analog for 2
LWRs like CDF and LERF, the non-LWR standard does not 3
specifically refer to these constructs of a Level 1 4
analysis, a Level 2, or a Level 3.
5 But instead, it frames it as having the 6
analysis start from the initiator going all the way 7
out to radiological consequence. So, it's intended to 8
be essentially a sort of fully integrated analysis.
9 And likewise, the Staff avoided the use of 10 the terms that define those typical transition points 11 in a PRA for LWRs, which doesn't mean they can't be 12 readily related to just because we're so familiar with 13 it for LWR activities.
14 But it's also important to note that while 15 Reg Guide 1.247 does talk about intermediate risk 16 metrics like CDF and LERF, justifying the use of an 17 intermediate risk metric in the context of satisfying 18 a full PRA analysis would generally expect to be 19 fairly challenging.
20 So, that's to say that if, for example, 21 someone for a non-LWR PRA submitted with some 22 intermediate risk metric that stops just before the 23 core is damaged, if you will, or there's damage to the 24 fuel, stops the analysis there but then develops a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
51 justification to show that the consequence metrics are 1
satisfied or that the quantitative path objectives in 2
the NRC Commission policy statements are satisfied, 3
are met.
4 That is generally expected to be a fairly 5
challenging exercise, but again, we don't dictate in 6
Reg Guide 1.247 what approach an Applicant should 7
follow.
8 In that regard, 1.247, like 1.200, is 9
something to help give confidence to an Applicant that 10 if this approach is used, which the Staff have already 11 approved and find acceptable, the review ought to go 12 smoother.
13 MEMBER BLEY: It sounds like you're 14 halfway through graded PRA fitting within this 15 framework, is that fair to say? You have to justify 16 what you're doing but you could.
17 MR. GILBERTSON: That's right, I guess it 18 relates to graded PRA but as I understand it and Marty 19 can certainly speak to this in more depth, graded PRA 20 is going to be more of if you've got a very small 21 source term and your reactor is not that complex.
22 Why do I have to do the full-blown 23 analysis? I can just show that even if I get to here 24 for any number or variety of sequences, the source 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
52 term is still just so small. But Marty, is that 1
something you want to speak to briefly?
2 MR. STUTZKE: Yes, one of the challenges 3
for the graded PRA is trying to define what we're 4
actually grading and the current focus of that effort 5
is looking at methods that could be done in lieu of 6
performing a PRA.
7 It's clear, as I've said before, whatever 8
methods you decide to use, you still need to look at 9
all the radiological sources and all the plan operated 10 states, and all the internal and external hazards like 11 that.
12 Now, in doing that whether you need to go 13 all the way out to the consequence evaluation hasn't 14 yet been determined.
15 But I would agree with Anders that the 16 focus on of the graded PRA would be to support 17 approaches such as a maximum hypothetical accident 18 approach to licensing.
19 It's similar to the question we do 20 research and test reactors.
21 MEMBER BLEY: Okay, thanks, Marty.
22 MR. GILBERTSON: I'll go ahead and move on 23 here. I don't want to shorten my colleagues for their 24 speaking time so I'll try and expedite this a little 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
53 bit.
1 So, just some of the additional 2
differences, like I mentioned before, 1.247 was 3
intended to really be able to accommodate a PRA that 4
would be used for an LMP application.
5 We understand those applications are very 6
likely to come in so we wanted to hit that head on and 7
make sure the guidance was available.
8 As far as NEI 2009 here, the Staff worked 9
together with industry, we commented on drafts that 10 they provided and this was all in the interest of 11 trying to reduce any of the exceptions.
12 In the end, we identified no exceptions 13 that needed to be taken. So, as a result, there's 14 nothing really to write an exception for in a table of 15 an Appendix.
16 So,
- instead, we just focused on 17 emphasizing parts of the guidance in NEI 2009 that the 18 Staff would like to people to pay attention to.
19 And the last four points here, I'll get 20 into those in the last slides and these are the scope 21 elements that are not addressed in Reg Guide 1.200.
22 So, Slide 16, please? These are the PRA 23 elements that are common to both Reg Guide 1.247 and 24 Reg Guide 1.200. So, there are about 15 of these 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
54 elements. Now, keeping in mind that Reg Guide 1.200 1
ostensibly addresses for most of the hazards at power 2
plain operating state.
3 There is some consideration of low-power 4
and shutdown operating states but it's in the context 5
of an internal events hazard and so not for other 6
hazards. So, it's a little bit of a different kind of 7
separation of the different pieces of scope.
8 Slide 17, please? So, some of the 9
similarities, both Reg Guide 1.247 and 1.200, they 10 have a table of hazards in the Appendix at the end of 11 the document that are intended to be considered in 12 development of a PRA.
13 Now, understanding this can serve as a 14 starting point, it's not intended to be an exhaustive 15 list that are the absolute minimum that have to be 16 considered.
17 In that regard, especially when meeting 18 the requirements in the standard, there still will be 19 a need to go through and ensure you have a process 20 that is systematically identifying what hazards could 21 potentially affect your plant, screening out hazards 22 that are judged not to affect it, et cetera.
23 So, those lists are not meant to be 24 comprehensive and represent a minimal list.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
55 Another similarly, this just goes to the 1
fact that the structure is generally the same between 2
the two reg guides in terms of telling what an 3
acceptable PRA is, speaking to the use of voluntary 4
consensus standards and a peer review process, 5
demonstrating acceptability of a peer review for an 6
application, and then of course the documentation that 7
you need to support a regulatory decision.
8 Slide 18, please. These are the four 9
Staff positions that I'll go over in detail for each 10 of these in the next slide. Slide 19, please?
11 Reg Guide 1.200 primarily addresses LWR 12 risk from the at-power operating mode like I mentioned 13 before, with some consideration of low-power and 14 shutdown operating modes.
15 Reg Guide 1.247 relates more to plant-16 operating states versus talking about at-power and 17 low-power shutdown operating modes.
18 So, one of the things that you'll see in 19 Reg Guide 1.247 is that we talk about at-power types 20 of plant operating states, or low-power shutdown types 21 of plant operating states.
22 One of the reasons we did this was really 23 to accommodate the notion there may be more than one 24 type of at-power state that a PRA is developed for.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
56 For example, if a plant or a design allows 1
for online refueling, that could be a significantly 2
different configuration of the plant than it is for 3
just normal at-power steady-state operations, 4
different systems might be disabled, et cetera, 5
whatever the case may be.
6 So, we wanted to be able to make sure we 7
were consistent with the non-LWR PRA standard and that 8
we were able to accommodate those potential for 9
different types of states.
10 And then again, the Staff positions in Reg 11 Guide 1.247, in many instances, they'll set a 12 precedent for future Staff positions and endorsements 13 of consensus standards for the LWRs.
14 So, for example, when the low-power and 15 shutdown LWR PRA standard is published, the NRC will 16 need to determine whether it's going to be endorsed.
17 And now that we'll have Reg Guide 1.247, again, we've 18 got this precedent for developing a Staff position.
19 And so
- again, certainly the Staff 20 positions in Reg Guide 1.247 are going to necessarily 21 inform that endorsement. Slide 20, please?
22 We have not yet developed a position on 23 internal fire PRA for low-power shutdown types of 24 plant operating states for LWRs, however, we do expect 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
57 that a submittal PRA could include this scope item 1
because of an application and requirements to include 2
full scope of everything.
3 This is a scope item for which there are 4
no requirements in a non-LWR PRA standard and as such, 5
the acceptability of the performance of that type of 6
PRA would be measured directly against the Staff 7
position in 1.247.
8 The Staff position was developed with an 9
understanding that a similar position may also be 10 developed for the future for LWR so again, looking 11 forward to the next technical revision of 1.200.
12 And finally, I just wanted to note the NRC 13 is performing research, we're in the midst of kicking 14 off a research effort to develop guidance on 15 acceptable means of developing an internal fire PRA 16 for low-power and shutdown types of plant operating 17 states.
18 That's intended primarily to support 19 non-LWRs and applications using the standard in Reg 20 Guide 1.247. But there will be natural connection 21 points between that consideration for non-LWRs and for 22 LWRs.
23 Slide 21, please.
24 Again, the Staff position on consequence 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
58 analysis is driven primarily by the anticipated LMP 1
applications, however, outside of LMP applications, 2
there are no regulatory requirements to develop a 3
consequence PRA or analyzing the risk out to 4
consequences.
5 Even still, the Staff believe it will be 6
important for Commission expectations related to a 7
consequence analysis to be met as provided in various 8
policy statements, the safety goal policy statement, 9
advanced reactor policy statement, et cetera.
10 Risk surrogates may be used, however, as 11 I mentioned before, the use of those risk surrogates, 12 the justification may be difficult to achieve, it 13 could be quite a complex exercise.
14 Slide 22, please. So, talking about risk 15 integration, again, the Staff have no previous 16 position though we do have some relatively generalized 17 guidance on risk segregation and risk integration in 18 NUREG 1855.
19 It's quite high-level but it represents at 20 least perhaps something of a starting point. The 21 Staff position on risk integration is again, anchored 22 in the Commission's expectations as it relates to 23 policy statements and meeting the qualitative health 24 objectives.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
59 A specific application may not use 1
relatively importance measures for this accordingly.
2 Like I said, it may only use absolutely risk measures 3
but the Staff still maintain the PRA should be 4
developed using relative importance measures to 5
determine what's important.
6 And then risk reporting thresholds, the 7
Staff are not considering those in the Staff position 8
because those are considered to be relevant on an 9
application-specific basis.
10 So, that's to say that just because a risk 11 contributor falls below a certain reporting threshold, 12 it may not necessarily be unimportant to the 13 decision-making process.
14 So, that's one of the reasons why we're 15 not considering these risk reporting thresholds.
16 That's the end of my slides.
17 MEMBER REMPE: This is Joy, I should have 18 jumped in a bit earlier and I apologize, but in the 19 section of C.1.3-17, the reg guide talks about 20 economic factors and how the economic consequences 21 should be quantified.
22 Are there any differences here to what 23 exists in the current other guidance for LWRs?
24 MR. GILBERTSON: You know what? To answer 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
60 that question, I would defer to Keith Compton, he is 1
our resident expert on consequence analysis and he's 2
been involved in both efforts related to LWRs and 3
non-LWR PRA.
4 Keith, is that something you can speak to, 5
to answer Dr. Rempe's question?
6 DR. COMPTON: This is Keith Compton from 7
the Office of Research. I just jumped in, it looks 8
like I came in at the right time.
9 The answer to that is the elements in the 10 reg guide and the non-LWR PRA standard largely follow 11 the supporting requirements that were developed in the 12 light water reactor PRA standard for Level 3.
13 I don't think there's anything that is 14 particularly inconsistent with between what we'd be 15 doing for, say, cost-benefit analysis, that's where 16 you would consider economic factors in regulatory 17 space.
18 MEMBER REMPE: I thought, correct me, 19 maybe I'm wrong, the reg guide said that you are 20 allowed to consider mitigating actions and things like 21 that. I just am wondering if that is consistent with 22 the current guidance for the LWRs.
23 DR. COMPTON: Do you consider the effects 24 of protected actions on both dose and cost, is that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
61 what you're referring to?
1 MEMBER REMPE:
And for economic 2
calculations, if there's land contamination or 3
whatever. I just am curious, again, did it go 4
further?
5 You're still saying, no, it's consistent 6
with what's there in the existing regulation, the 7
existing guidance for LWRs. I shouldn't call it 8
regulation.
9 DR. COMPTON: I will look into more of it.
10 I guess I would just point out that if 11 you're doing say a maximum calculation where you're 12 looking particularly at long-term effects, you're 13 doing a simultaneous calculation, both of the effects 14 of the protected actions that reduce the consequences, 15 that reduce the dose, and then your economic costs 16 would arise from those protected actions.
17 MEMBER REMPE: Look into it and if you see 18 something different please let us know. I just was 19 curious because it seemed to me it was a little more 20 realistic than what we were allowed to do for the 21 LWRs.
22 That was just a read-through and I could 23 be wrong.
24 DR. COMPTON: I will take that question 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
62 back to the folks that are working on the new cost 1
benefit guidelines, which I think is what you're 2
probably referring to.
3 MEMBER REMPE: Absolutely, thank you.
4 MEMBER BLEY: Anders, two things. One, 5
we've gotten pretty far over the time and I want to 6
get to the other talks but I wanted to let you get 7
through all this.
8 How many more slides do you have?
9 MR. GILBERTSON: I'm finished, I was just 10 able to hand it off to Hanh.
11 MEMBER BLEY: Before you hand off, Dr.
12 Bier has a question. Vicki?
13 MEMBER BIER: I hope this is going to be 14 quick. I'm just trying to figure out how all the 15 pieces fit together especially with regards to peer 16 review.
17 So, for example, you stated in this last 18 part that the relative risk criteria should be used to 19 develop the PRA even if the PRA results are not 20 expressed that way.
21 But as I understand it, the licensee 22 wouldn't even need to submit the PRA to the NRC if 23 they go through peer review, et cetera. So, is the 24 peer review process specified to level that it would 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
63 have to check those kinds of things?
1 Like what are the relative risk criteria 2
used in developing the PRA?
3 MR. GILBERTSON: If the user of the reg 4
guide is intent on meeting the Staff position, then 5
yes, it would need to address that.
6 MEMBER BIER: So, the peer review would be 7
an NRC-oriented peer review, are you doing the things 8
that NRC expects?
9 MR. GILBERTSON: Right.
10 MEMBER BIER: Got it, thank you.
11 MEMBER BLEY: Thanks, Anders. Before we 12 go ahead with Hanh and Marty, I know I requested that 13 part of the presentation today but I thought we needed 14 to go through all yours, we're going to take a short 15 break.
16 And Carl, look through your slides quickly 17 and see if you can cut things down just a little bit 18 to make up for the time that's passed.
19 At this time, we're going to take an 20 almost 15-minute break and we'll come back at 11:20 21 a.m. East Coast time. We are recessed for 13 minutes.
22 See you all back in a minute.
23 (Whereupon, the above-entitled matter 24 went off the record at 11:07 a.m. and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
64 resumed at 11:19 a.m.)
1 This is Dennis Bley again, we're going to 2
come back into session but one announcement before we 3
do. For personal reasons, I'm going to have to drop 4
off the call some time around an hour from now.
5 Dr. Dave Petti will take over chairing the 6
meeting and wrap it up if we're not done by then.
7 Given that we've slipped the schedule a bit, we 8
probably won't be done by then.
9 Hanh, you go ahead with your talk, if 10 there are things in your slides that we've already 11 talked about, maybe you can skip over them to try to 12 get through these a little faster and we look forward 13 to your presentation.
14 Hanh, are you ready?
15 MR. PHAN: Yes, sir.
16 MEMBER BLEY: Please, good.
17 MR. PHAN: Good morning, again, my name is 18 Hanh Phan, a senior PRA analyst in NRR, Division of 19 Branch Reactors. Closely watching the clock, there 20 are four more presenters after mine. I have 29 slides 21 in my presentation.
22 With that, I will adjust my talk. For 23 some slides I will not go over all bullets, please, 24 stop me if you have any questions. Next slide, Slide 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
65 24, please.
1 In this portion of the program, I will go 2
over the key guidance of Section C of Reg Guide 1.247 3
and the start position for non-LWR PRA standard, 4
documented in Appendix A of Reg Guide 1.247.
5 Next please. First, I'd like to recognize 6
the effort of the technical staff for leading the 7
reviews of these technical elements in the non-PRA 8
standard and the peer review process in NEI 2009.
9 Next, please. Before getting into the 10 details, I would like to briefly discuss the battery 11 and the Applicant's ability of Reg Guide 1.247. 1.247 12 addresses all radiological sources at the plant.
13 So, as reactor core is spent fuel, fuels 14 repossessing facilities and accidents scenarios that 15 lead to the radioactive list of multiple sources.
16 It's also addresses more internal hazard and all 17 external hazards.
18 It addresses all plant operating stage 19 including at power, low-power, and shutdown. In 20 general, we expect that.
21 The non-LWR PRA should be a Level 3 PRA, 22 which develops the frequencies of excellent scenarios 23 from an initiating event until the release of 24 radioactive materials to the environment and should 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
66 include the estimation of the consequences that result 1
from the release.
2 Next please. Slide 27. This reg guide 3
applies to applications for non-standard LWR licensing 4
under 10 CFR Part 50. Of those, the current 5
regulations do not require Applicants for PAC50 6
construction permits or operating licenses to provide 7
PRA-related information.
8 However, the Staff is currently working on 9
the proposed new language in PAC50, which will require 10 PRA information in the application similar to the 11 requirements in PAC52.
12 This reg guide also applies to the 13 application for non-standard UR licensing under Part 14 52, including DC, COL, SDA, and ML. This reg guide is 15 also coordinated with Pact 53 to make an effort 16 currently under development.
17 Page 8, please, Slide 28. Furthermore, 18 1.247 only applies to the stationary non-standard URs 19 for those reactors that are at the site. The reactors 20 are constructed at an offsite facility and 21 subsequently transported and installed at a site.
22 This addresses PRA used to assess the risk 23 of comporting the reactors from an offsite facility to 24 the site and does not address mobile reactors, which 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
67 may be relocated to multiple sites after the initial 1
recalibrating.
2 Slide 29, please. 1.247 endures all 18 3
elements in the non-UR PRA standard in addition to 4
that.
It also endures the definition PRA 5
configuration
- control, peer
- review, and newly 6
developed methods of the standard.
7 MEMBER BLEY: Can you go back one slide to 8
28? I want to ask you a question about that. The 9
last two bullets does not address the risk of 10 transporting from an offsite facility to a site.
11 It also does not address from the site to 12 some other facility for taking it apart and 13 reassembling it.
14 When are those last two bullets going to 15 be covered? Is that going to be under separate 16 guidance or will that be in a revision to this 17 guidance?
18 MR. PHAN: Based on my understanding, 19 those are to be addressed by NMSS, not by the NRR.
20 And we have no plans to update the standard on this 21 reg guide.
22 MEMBER BLEY: Just for the Staff's 23 information, and Derek, if you can track this, we 24 ought to talk to NMSS and figure out what's happening 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
68 in that area. Sorry to interrupt you, Hanh, jump 1
ahead to where you ought to be.
2 MR. PHAN: No problem. Thanks, sir. So, 3
we're back to Slide 30. Regarding the non-mandatory 4
appendix in the standard, they can be divided into two 5
groups. Not to support the understanding of various 6
supporting requirements and commentaries.
7 The NRC Staff generally accept the Staff 8
of why no opinions about the commentaries. Next 9
slide. In general, about 20 percent of the supporting 10 requirements separate between Capability 1 and 11 Capability 2 for comparison purposes.
12 For each technical element, the blue bars 13 in this chart indicate the SR with the same 14 requirements for both Capability 1 and 2 while the 15 orange bars show the SR with different requirements.
16 Next please. Slide 32. The next slide in 17 my presentation discuss the trial use records.
18 So, first, in Section C1, acceptability of 19 a PRA and its resource, the Staff accept the 20 acceptability of a PRA and its resources with respect 21 to PRA scope, level of details, conformance with 22 consensus standard, elements and plans representation 23 of a PRA, similar to Reg Guide 1.200.
24 MEMBER DIMITRIJEVIC: I have a question on 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
69 these. This is one of my concerns with this. Is 1
acceptability of the PRA the same as the acceptability 2
of the PRA result?
3 Because sometimes we set the standard 4
defines what is required and it doesn't specify how to 5
do it.
6 That defines what is required and it 7
doesn't specify what to do it. So, basically, 8
standard defines everything which needs to be done to 9
have a good PRA but it doesn't tell us anything is 10 done technically correct or not.
11 Because it doesn't specify how to do it.
12 So, I have an issue there, it's acceptability of the 13 PRA the same as the acceptability of the PRA results?
14 Do you understand what my concern is? Because the 15 standard doesn't specify how to do it.
16 Different Applicants can choose different 17 methods to address different requirements. Nobody 18 guarantees that these methods would be technically 19 correct, right?
20 MR. PHAN: Yes, I see your point and 21 that's a great point. Yes, we combined both in the 22 acceptability in this reg guide but I see the 23 differences there. I totally see that, the standard 24 only showing what to do, not how to do.
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70 So, we later did the peer review that may 1
rely on the outcome from that peer review and evaluate 2
the result of the PRA for specific application.
3 But I see your point and that's clear to 4
me, we may consider how to make the language clear in 5
the reg guide. Thank you.
6 Slide 33, I will not go over the details 7
in this slide, we don't have time. But for each 8
criteria there are more details on this slide for PRA 9
acceptability. Next please.
10 Now, in Section C3, the most frustrating 11 acceptability of PRA and its resources, okay, so for 12 all applications, the PRA-related information provides 13 and the submitter should describe the PRA scope, the 14 level of detail, and plans representation.
15 Demonstrate the PRA has been developed and 16 used in a technically acceptable manner and identified 17 application-specific acceptance criteria and 18 demonstrate they have been met.
19 Section C4, the next slide, please, 35.
20 Documentation to support a regulatory 21 decision, in Section C4, documentation of the PRA 22 milestone and the analysis confirmed or should confirm 23 that appropriate information, those that are visible 24 for the staff audit inspection and submit the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
71 information, submit it in the application.
1 Note that the archival PRA documentation 2
may be required on an as-needed basis to facilitate 3
the NRC Staff's review of the application.
4 Slide 36. In the Reg Guide, we 5
specifically list the information and there's a PRA 6
documentation. I will not go over these bullets.
7 Next, please, Slide 37.
8 We also listed in the reg guides the 9
submit the PRA documentation should be included in the 10 application. Slide 38, now the Appendix A that the 11 Staff position and Section C2 on PRA peer review 12 process.
13 Before getting there, I'd like to show you 14 the bigger picture. About 80 percent of the 15 requirements in the non-standard PRA standard was 16 taken as if from the LWR PRA standard.
17 Secondly, during the first consideration 18 ballot of the non-standard PRA standard, NRC Staff 19 submitted 489 comments presented a set of Staff 20 reviews and perspectives.
21 During the recirculation ballot, NRC Staff 22 submitted additional 70 comments included a mix of 23 proposed technical transitions and observations 24 related to the regulatory issues.
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72 Next please, Slide 39. Similar to Reg 1
Guides 1.200, the start position on each requirement 2
in the non-standard PRA standard is classified as no 3
objection with clarification and no objection subject 4
to the following qualification that the Staff provide 5
this position.
6 Next please. Slide 40, here are some key 7
rationales for the Staff position. During the 8
recirculation ballot, about 70 NRC comments, JCNM 9
decided that.
10 About 20 comments need to be addressed in 11 the light water reactor Level 1 PRA standard first but 12 not in the non-standard UA PRA standard yet. About 8 13 comments were considered as regulatory issues and was 14 not addressed in the non-standard PRA standard.
15 Other rationales include mute issue found 16 after the ballot. Issue was not addressed, adequately 17 addressed, during the ballot. Issue was not fully 18 addressed by JCRMs.
19 And nearly habits for consistencies with 20 the start position and Reg Guide 1.200 Revision 3.
21 Next please. Slide 41.
22 This slide shows that in Appendix A of Reg 23 Guides 1.246 there are 147 Staff positions, 114 are 24 classification and 33 are qualification. In the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
73 non-LWR PRA standard, there are 214 high-level 1
requirements and 1233 supporting requirements.
2 In addition to that, the language provided 3
in the definition section and other sections show that 4
Staff has about 10 percent position so in general, we 5
believe that we're not much far away from each other.
6 Next please. Slide 42. Out of these 147 7
positions, the Staff identified 17 of them, more 8
substantiative and binned them into five groups.
9 Group 1, low-power and shutdown risk 10 issue, Group 2, external hazard, Group 3, ever 11 Commission, Group 4, risk significance, Group 5, 12 reporting requirements. Next please. Slide 33.
13 MEMBER BLEY: Hanh?
14 MR. PHAN: Yes, sir?
15 MEMBER BLEY: I just wanted to comment, 16 this is my personal opinion, when I first got the reg 17 guide and saw the large number of these, I was 18 concerned we had maybe a real disconnect between the 19 Staff and the standard.
20 But after I read them carefully, I'd 21 rather than appreciate almost all of your 22 clarifications and qualifications, I thought they were 23 important and I congratulate you on those, but go 24 ahead.
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74 MR. PHAN: Thank you, that's what we are 1
here for, not try to convince anyone to accept where 2
we are but hopefully, you agree with the Staff's 3
position and everything we have in the documents up to 4
this point.
5 Next please. So, Group 1, low power and 6
shutdown risk. In this first group regarding low 7
power and shutdown, the Staff expects that low power 8
and shutdown types of evolutions should be addressed 9
for all stages of the licensing process.
10 That's shown in the POS note to and for.
11 In addition to that, to avoid including potentially 12 significant contributors to risk, the stop of 13 capability in POS is one requirement, that should be 14 the same as the scope of the Capability 2 requirement.
15 So, we combined those into one 16 requirement. Furthermore, in POS-B1, the last row, to 17 ensure that the POS grouping, this impacts significant 18 event sequences.
19 Additional requirements, Item C in the 20 last row, the last column, was added to the Capability 21 one.
22 Group 2, next slide, Slide 44, external 23 hazards, risk. For seismic facility analysis, SFR-C1 24 and C2, in addition to specifying the basis for 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
75 screening of components and achieving the facility 1
thresholds, the Staff adds to the requirement the 2
justification for those selected basis in the hazard 3
screening supporting requirements as X-A3.
4 The requirements do not specifically 5
mention hazard, therefore, the Staff added that term 6
to their requirement. The last one, high winds, the 7
Staff believes that the 150 most distant mentioned in 8
the supporting requirements, A-A5, is a bit churly.
9 Therefore we replaced that with the term 10 sufficiently far away. Next please. Regarding the 11 seismic hazard analysis, supporting requirements SA-12 P5, this does not include the use of the existing 13 probabilistic SA for a site.
14 The impacts of an updated catalog on the 15 use of the existing probabilistic SSA, therefore, the 16 Staff adds the requirement on the demonstration that's 17 updated catalog of upgrades.
18 It does not make the existing 19 probabilistic variable. For hazard screening, the 20 Staff deletes Item F from supporting requirements best 21 B5. In the preferences there's a 5 on the reporting 22 values, not the screening values.
23 Next
- please, Slide 46, errors of 24 commission. In this Group 3 the Staff adds to the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
76 human reliability element under high-level 1
Requirements E and supporting Requirements HR-E4.
2 The consideration of errors of Commission.
3 Next please. Slide 47, the risk significance for that 4
the Staff adds additional clarification to note N-1, 5
regarding the proper use of relative and absolute risk 6
significance.
7 You can see that in the last column and in 8
this column, these are all the Staff language. Next 9
please. Slide 48. In Group 5 reporting requirements 10 the Staff does not consider reporting as one of the 11 PRA requirements.
12 When determining the PRA acceptability for 13 an application, the Staff concluded that should 14 supporting requirements should be provided by the 15 appropriate regulatory authority on an application-16 specific basis.
17 Next please, Slide 49.
18 MEMBER BLEY: Hanh?
19 MR. PHAN: Yes?
20 MEMBER BLEY: I'd like to interrupt you at 21 this point with a couple of comments and a question.
22 The first comment is in several places in your 23 resolution, you speak of credit or do not credit a 24 human failure event and a PRA and I want to suggest to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
77 you that you change that language.
1 I think it ought to say include the HFE 2
and the PRA and the reason I don't like your use of 3
the word credit is it's left over from traditional 4
safety analysis.
5 And I think to a lot of people who read 6
this who aren't extraordinarily familiar with PRA, 7
they will read it as saying you assume the operator 8
will do it correctly, you credit the operator action.
9 And I think that language is going to get 10 you complaints that you don't need and complaints that 11 aren't really on target. So, I really hope you'll 12 think about changing that.
13 I made a comment in my opening remarks 14 about the search for initiating events and I hope you 15 consider that as well. On your FLPP B6, but it 16 happens many other times, you talk about, this one is 17 about, internal flood partitioning.
18 Do it via walk-downs, which is a great 19 idea, but if you can't do a walk-down, you can't do 20 it.
21 And I wonder, this is a question, you're 22 decades past designers and even licensees who would 23 build full-scale 3D models of their plant so you could 24 look at some of these issues at least preliminarily.
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78 You'd have to reconfirm as built. But I 1
suspect now most of them have 3D computer models, they 2
don't build the big models anymore, where you could do 3
some of this at least in a preliminary sense. Have 4
you thought about that?
5 It shows up in quite a few places where 6
you can't do it because the plan isn't there but if 7
you have those 3D models you could at least confirm 8
there's a potential problem. As long as it's built to 9
look like the 3D model, you don't have a problem.
10 MR. PHAN: Thank you for your advice.
11 In the interim start guide 28 for light 12 water reactors license application, we told the 13 Applicants that for plants walk-down, because of the 14 early stage of the design, the Staff mostly affect the 15 paperwork is that during the year.
16 But yes, which technology improvements we 17 may have more revisions on site and we can have more 18 information contributing to the decision-making.
19 Thank you, yes, we will consider that.
20 MR. VASAVADA: This is Shilp Vasavada from 21 the NRC Staff, can I make a comment here?
22 MR. PHAN: Please do.
23 MR. VASAVADA: This is again Shilp 24 Vasavada and to your point, I think it was Member 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
79 Bley, Step 7C in I think Section 5 of 2009 does 1
accommodate those types of information in lieu of 2
lock-down for certain stages of plant construction and 3
development.
4 I'll quote directly, peer review is for 5
PRAs in the design and/or pre-operational phases, can 6
rely on computerized walk-downs. It is important that 7
peer reviewers identify assumptions, example 8
configurations of SSCs.
9 And that is for operators that impact 10 and/or have been used in the PRA development. The PRA 11 reviewers would confirm the consistency of the 12 assumptions with the PRA during the review of the 13 relevant technical and documentation SR, end quote.
14 MEMBER BLEY: Thank you very much. When 15 I read that and saw computerized walk-downs, I just 16 envisioned a spreadsheet where you kept track of 17 things and I didn't get the sense you were talking 18 about 3D models.
19 But if you were, that's great and if you 20 added clarity, that would be even greater but thank 21 you for filling me in on that.
22 MR. VASAVADA: Thanks for that, we'll take 23 that back about additional clarity. Thank you.
24 MR. PHAN: Please go to Slide 48, thank 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
80 you. 49, thank you. NEI's 2009, the Staff received 1
the initial document on June 1, 2020. The Staff 2
reviews observations to NEI during the public meeting 3
on July 22, 2020.
4 We received another revision of this 5
document latest August last year. We provided 6
additional comments in another public meetings on 7
October 26th of last year.
8 With all of that, NEI submitted to us the 9
revision of NEI 2009 on May 5, 2021, which addressed 10 most of the Staff's feedback on the guidance. That's 11 just some background for your information. Next 12 please, Slide 50.
13 So, 2009 revision was based on a similar 14 guidance document. NEI 1707, Revision 2, which we 15 endorsed in Reg Guide 1.200, Revision 3. So, NEI 2009 16 addresses radios plus courses hazards, POS, and 17 therefore PRA analysis.
18 And the process in that guidance is 19 applicable for peer reviews confirmed for a PRA at any 20 stage of the plant's lifecycle. The Staff finds the 21 reg guidance in NEI's 2009 Revision 1 is acceptable.
22 So, we endorsed 2009 without exception in 23 Section C.2.2 of Reg Guide 1.247. It should be noted 24 that the non-standard PRA standard also contains 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
81 requirements for the performance of acceptable peer 1
review process.
2 The Staff also reviews those requirements 3
and has no exceptions to them. Next, please. This is 4
my last slide. NEI's place to bylaw the peer review 5
process so the Staff hopefully to observe the bylaws.
6 And based on the observations, we may 7
enhance the start position in Reg Guide 1.247. So, 8
with that, I would turn to Mr. Marty Stutzke to go 9
over some non-standard PRA acceptability issue.
10 Please take over, Marty.
11 MEMBER BLEY: Marty, how long do you think 12 your set is going to take?
13 MR. STUTZKE: Ten minutes.
14 MEMBER BLEY: Go ahead.
15 MR. STUTZKE: Very fast. So, there were 16 ten issues identified in our white paper, I've listed 17 the references here.
18 And as Michelle had said before, we either 19 addressed them in Reg Guide 1.247 or they're being 20 addressed in other guidance. Or we're doing some 21 research activities.
22 Slide 53. So, the first issue is 23 providing guidance on initial licensing. Remember the 24 model that Reg Guide 1.247 is a basis for all PRAs and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
82 then there would be application-specific regulatory 1
guidance.
2 And the focus has been on the industry 3
TICAP guidance and its endorsement and the Staff's 4
event or after content of application, ARCAP guidance, 5
et cetera. So, that's the example of the specific 6
application regulatory guidance.
7 We're not currently developing any non-8 LMP-based guidance at this time. Item 2 on graded 9
PRAs. We have a working group formed to explore 10 alternatives to PRA that should achieve the same 11 underlying purposes.
12 To give you a flavor of what we're looking 13 at, perhaps we could adapt the integrated safety 14 assessment process required for Part 70 licensees, we 15 have NUREG 1513 which provides guidance on developing 16 that.
17 And I
understand that the SHINE 18 application has modified that in lieu of performing a 19 PRA. So, there may be some possibilities there.
20 Issue Number 3, guidance on voluntary risk-informed 21 applications.
22 We've initiated work requests. This is 23 basically going to either be an upgrade of things like 24 Reg Guide 1.74 or a parallel document applicable to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
83 non-LWRs.
1 The big question at least in my mind is 2
adapting the numerical risk acceptance guidance from 3
core damage frequency and large early release 4
frequency to something that is more technology-5 neutral, perhaps the QHs directly.
6 We'd already talked about Item 4, about 7
the use of risk surrogates and the language in Reg 8
Guide 1.247 allows them. The question, then, about 9
the use of seismic margins analysis, that's not 10 addressed specifically in the standard.
11 We feel obliged to address it in our 12 regulatory guidance because the Staff requirements 13 memorandum on SECCY-93-087 allows the use of seismic 14 margins analysis.
15 And of course, to employ SMA you need to 16 have a risk surrogate, something like large release 17 frequency or something.
18 So, anyway, anybody that wants to use 19 seismic margins is encouraged to talk to us during 20 pre-applications. Slide 54, please.
21 MEMBER BLEY: Marty?
22 MR. STUTZKE: Yes?
23 MEMBER BLEY: On Item 2 up there and if 24 this is politically inappropriate to answer that's 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
84 fine, but if you can I'd appreciate some information 1
and maybe when Victoria Anderson makes her comments 2
later she'll touch on this.
3 We hear stories and we've had 4
presentations by people who think for their reactors 5
a PRA is just way too much overhead and too costly and 6
on and on.
7 We also hear stories and see things where 8
some developers have come up with what they found to 9
be a reasonable approximation to a full PRA but 10 limiting the areas where they can bound off 11 consequences.
12 So, we're getting a real mix of way too 13 hard and it works just great. Have you heard anything 14 along the way along those lines?
15 MR. STUTZKE: My impression from sitting 16 in on a variety of public meetings related to Part 53 17 is the industry is not speaking with a single voice 18 here.
19 Some people are greatly wedded to LMP and 20 the use of PRA and they're all the way at the other 21 end of the spectrum, people just don't see the benefit 22 of doing it.
23 So, we're trying to be accommodating.
24 Thinking about it in terms of either PRA is a leading 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
85 role that would be used to support things like LMP, or 1
PRA in a more traditional role where the purpose of 2
the PRA is to confirm a deterministically-based 3
design, look for outliers or something that was missed 4
or something.
5 And the third option that we're looking 6
at, we call it the dose-consequence-based alternative 7
and that would pick up on things like integrated 8
safety assessment, we're looking at some OSHA 9
regulations and some EPA regulations that seem to be 10 similar.
11 They reference a document by the Center of 12 Chemical Process Safety of the American Society of 13 Chemical Engineers on these techniques. So, we're 14 trying to be accommodating of all anticipated 15 Applicants.
16 MEMBER BLEY: Thanks.
17 MR. STUTZKE: It's an enormous problem.
18 MEMBER BLEY: I really appreciate your 19 comments and we look forward to hearing more about 20 that in some other meeting in the future.
21 MR.
STUTZKE:
Slide 54, please.
22 Completeness, certainty, we've initiated some work 23 requests in the Office of Research concerning 24 uncertainty analysis in general and the low-power 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
86 shutdown fire PRA.
1 I wanted to point out that there is an 2
existing NUREG CR-7114 that provides a framework for 3
doing low-power shutdown fire PRA.
4 It tends to be qualitative in nature, at 5
least my vision is we'll end up with something that is 6
analogous to NUREG CR6850 which will be a more 7
complete quantitative methodology. But that will take 8
some time.
9 Item 7 about selecting a bounding site, 10 the notion there is you have to design the reactor for 11 the worst possible seismic hazard and the worst 12 possible hurricane hazard, et cetera.
13 And you ended up rapidly with a site 14 that's not physically realistic. So, we've allowed 15 each Applicant to propose and justify on a
16 case-by-case basis what their bounding site is.
17 Item 8 is the notion that various 18 supporting requirements apply during different 19 licensing stages. In other words, they contain 20 qualifiers like prior to operation or during 21 construction, et cetera.
22 So, the requirement would apply. So, I 23 think of it as the supporting requirements turn on and 24 turn off at various stages and we wanted to try to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
87 make that explicit to relate the more broad language 1
that's used in the standard to specific licensing 2
stages as the NRC recognizes.
3 For example, construction permits and 4
operating
- licenses, design certifications, 5
manufacturing licenses, standard design approvals, 6
versus combined license versus the fuel load PRA, et 7
cetera.
8 Our intent is to build an interim Staff 9
guidance document to be very specific as to which 10 requirements apply when.
11 Item 9, the use of absolute relative risk 12 significance criteria. We've addressed it in the reg 13 guide and the next three slides talk about this in 14 some detail.
15 We've also talked previously about Item 16 10, the use of peer reviews. Notice that they can be 17 full scope or focused scope to demonstrate the 18 acceptability of the PRA.
19 A couple of points I would make about peer 20 reviews.
21 One is a concern about the lack of 22 qualified peer reviewers for non-LWRs makes it 23 difficult and there are concerns that have been 24 expressed by some reactor designers about their desire 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
88 to maintain their proprietary information proprietary.
1 And so they're therefore discouraging of 2
peer reviews. I would point out that the Staff also 3
has the option to conduct a PRA audit where we will go 4
on site to an Applicant's office and look in detail at 5
the PRA and put in all the logic models, all the 6
supporting data, et cetera.
7 So, my personal impression or opinion is 8
if an Applicant does not want to do a peer review for 9
one or the other, then we will do one for them and 10 they can expect the corresponding increase in the 11 schedule of getting the SER completed.
12 Slide 55. Risk significance. In general, 13 it's used for a couple of reasons like this. The goal 14 or outcome is to at least identify what's important.
15 It's used in construction of a PRA where 16 there are specific requirements that says the risk-17 significant items do, for example, X, Y, and Z so you 18 need to wait to be able to determine to which items 19 those apply.
20 And items can be things like basic events, 21 any one of the technical elements like that.
22 Personally, I've always used importance measures as a 23 tool to debug the logic models, looking at symmetry 24 across the trains.
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89 One would expect the importance measures 1
to be similar or identical. And of course, it's an 2
iterative process.
The second use of risk 3
significance is in reporting PRA results, what we 4
actually get to look at.
5 The more traditional approach is to use 6
relative risk significance where you're being measured 7
and normalized to the total risk. In contrast to 8
absolute risk significance, you're normalizing to a 9
specific risk target.
10 For
- example, the LMPs frequency 11 consequence target curve or the QHOs.
12 Think of it like this, if I take some 13 measure of importance and I rank order the list of 14 basic events that come from the PRA, what we're 15 discussing here between relative versus absolute risk 16 significance is where to draw the line on that very 17 long list.
18 And the items above the line would be 19 significant and the items below the line not as 20 significant. So, these are just two different ways of 21 deciding where to draw the line on the list.
22 If you'll flip to Slide 56 I'll give you 23 an example.
24 So, this is basic events risk significance 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
90 and the relative process, the traditional process will 1
use the vessel importance measure greater than 0.005, 2
the risk achievement, the raw value greater than 2 to 3
identify risk significant basic events.
4 In contrast, what is proposed in the 5
standard that we've accepted without clarification or 6
qualification would say on an absolute basis, a basic 7
event is significant of increase of 1 percent to any 8
identified target or if the basic event is assumed to 9
fail you would exceed the criteria, exceed the target.
10 So, you can begin to see these are similar 11 in flavor but they greatly reduce the number of risk-12 significant items. Slide 57, I've given an example of 13 risk-significant event sequences or event sequence 14 families.
15 What we've always done using relative is 16 to say anything that contributes 95 percent or 17 anything that individually contributes 1 percent by 18 itself like this.
19 Whereas, in contrast on the absolute, the 20 percentages are relative to the absolutely risk 21 target.
22 With that, I believe I'm done.
23 MEMBER BLEY: Thank you very much, Marty, 24 we appreciate the presentation and discussion. Do any 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
91 members have anything for Marty before we switch over 1
to the standards group?
2 Okay, at this time I'm going to go to Karl 3
Fleming of the JCNRM for his presentation.
4 Before we do, I just wanted to announce to 5
everyone that Karl was awarded the 2021 American 6
Nuclear Society prestigious Tommy Thomson Award for 7
lifetime contributions to the field of nuclear safety.
8 Karl, our congratulations. As you talk, 9
any of the things we brought up earlier with the Staff 10 that you want to comment on, we would appreciate it 11 and I guess your talk is future activities.
12 So, we're interested in whether you were 13 surprised by the reg guide or not and whether you or 14 the group expects that there will be a revision within 15 a couple of years on this standard.
16 Karl, please go ahead.
17 MR. FLEMING: Thank you very much, Dennis.
18 I appreciate your congratulations.
19 If we can go on to the first slide, 20 please. The next slide.
21 Yeah. This is just my personal opinions.
22 This is the result of a first look at the Reg Guide.
23 I'm sure I'll have more to say once I do a more 24 careful review. These are my personal views, and do 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
92 not reflect any official position of JCNRM.
1 Next slide, please.
2 I don't have enough time to go through all 3
the bullets here, but there's some background here 4
that lays out the process we followed to get this 5
thing balloted through two recirculation reviews.
6 Some key points I wanted to make here was 7
that our disposition of the first round and second 8
bound ballot reviews that we got from the NRC, when we 9
got to the end the NRC agreed with our unanimous 10 decision to publish this standard based on the way we 11 had dispositioned all those comments.
12 Yes, on one of your questions, Dennis, I 13 was a
little bit surprised to see so many 14 clarifications and changes at the end. However, I've 15 done a little bit of analysis of the breakdown of 16 those, which I'll comment on later, which I think 17 brings out some important points.
18 But I wasn't party to reviewing the Reg 19 Guide on -- Reg Guide 1.200, but I was a little bit 20 surprised to see the method by which the 21 clarifications are presented in a form of a markup of 22 the document. And I guess if I were doing it, I would 23 rather, given the fact that the standard says what it 24 says, the requirements are basically written down in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
93 the standard, which has been unanimously approved.
1 I think it would be more useful to have 2
the staff say how they expect these requirements to be 3
met in terms of how they express clarifications. But 4
I know there's a Reg Guide 1.200 precedent here.
5 So, let's go on to the next slide, please.
6 One thing I wanted to sort of nail down 7
here, I think it's contrary to the discussion by 8
Anders and some of the other commenters so far. This 9
standard does not support the use of surrogate risk 10 metrics, period, full stop. We do, we do talk about 11 the user can define intermediate states like, for 12 example, a core damage state if he wants to define 13 what he or she wants to define on.
14 But we do not support stopping at a 15 surrogate spot in the model and expressing results in 16 that term. All the risk characterization, risk 17 significance determination and everything is all part 18 in our risk integration element. And they all relate, 19 they all include, relate to a quantification of the 20 frequencies and radiological consequences of event 21 sequences and --
22 MEMBER BLEY: Karl.
23 MR. FLEMING: Yes?
24 MEMBER BLEY: If I could. When I heard 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
94 Anders speak I think he, he expressed it in the same 1
terms you did, as intermediate points.
2 MR. FLEMING: Yes.
3 MEMBER BLEY: Hanh had spent a lot more 4
time talking about surrogates.
5 And I understand your point. And they'll 6
help us.
7 Go ahead.
8 MR. FLEMING: Yeah. Anyway, so, so anyway, 9
we really don't have surrogate risk metrics as risk 10 metrics.
11 On sections C.1.3 and C.1.4 I look at it 12 as sort of paraphrasing what's in the standard. But 13 this paraphrasing was in different language, and many 14 things were left out. Rather than try to cover the 15 same ground that's in the standard in terms of 16 objective, attributes, and so forth, it would be more 17 useful to focus on what the staff wants to clarify.
18 Because in those sections I would have to do a lot of 19 analysis to try to find out what's different and 20 what's left out and so forth between those.
21 Let's see. A lot of the clarifications 22 sin Appendix A refer to items that are shared with the 23 supporting standards.
24 And I want to make a, I think, a very 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
95 important point. One of Hanh's slides broke down the 1
clarifications by technical element. And those of us 2
that, you know, were involved in the standards, the 3
most -- the elements where the non-light water reactor 4
changes were most significant were in initiating 5
events, event sequence analysis, event sequence 6
quantification, and mechanistic source terms, and risk 7
integration. That's where the stuff that's really 8
different about this standard and the LWR standard 9
reside.
10 There were zero comments on IE-ES 11 quantification and mechanistic source terms, and only 12 two comments or clarifications on risk integration, 13 which just have to do with reporting.
14 MEMBER BLEY: Karl.
15 MR. FLEMING: Yes.
16 MEMBER BLEY: I don't want to interrupt you 17 again, but this is more functional. As soon as I'm 18 done speaking, Dave Petti will take over chairing this 19 session.
20 I appreciated the things you just said.
21 And I think the staff might make some notes here. I 22 know they're trying to be parallel to 1.200, but 23 they've written a new Reg Guide. And the idea that 24 rather than changing the words in the standard they 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
96 are saying here's what you need to do to meet the 1
standards requirement in our view, I think is probably 2
a more correct way to phrase things. So, I hope 3
they'll think about that.
4 MR. FLEMING: Right.
5 MEMBER BLEY: I won't get in your way 6
anymore. Please, go ahead.
7 Oh, the last thing is, and this is for 8
Dave, too, although our agenda says the meeting ends 9
at 12:30 Eastern Time, our overall schedule shows we 10 had to block all the way to 1 o'clock. So, we can 11 keep going past 12:30 if need be.
12 But go ahead. Thanks, Karl.
13 MR. FLEMING: Yeah, thanks.
14 And along those lines, so, I haven't done 15 the analysis of the, of the 147 comments. Only two 16 relate to the technical elements where the non-light 17 water reactor meet is. I suspect that the vast 18 majority of the 145 remaining clarifications are 19 really comments that are shared with language in the 20 LWR standard as well as the non-light water reactor 21 standard.
22 I think it would be helpful in the revised 23 Reg Guide if the staff could sort of focus on, or at 24 least identify which of the clarifications are really 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
97 either unique to non-light water reactors or have 1
unique significance to non-light water reactors, 2
because that would affect the way the Standards 3
Committee will manage them.
4 MEMBER BLEY: It's Dennis again. I wanted 5
to get in one question to you.
6 We talked with the staff a bit about do 7
you envision eventually there just being one standard?
8 And I know the standards process is trying, so I don't 9
know if that's ever going to pass. But it sure seems 10 like a reasonable end point to hope for.
11 MR. FLEMING: Yeah. My personal view is, 12 you know, our, our standard is technology-inclusive.
13 There's no reason why it couldn't be used on any 14 reactor. But the JCNRM position is we have a separate 15 standard for light water reactors, so we try to steer 16 this and emphasize the "N" in the non-light water 17 reactor standard. That's the JCNRM position. We have 18 separate standards.
19 But technically speaking, I think we could 20 make this a standalone standard for all reactors if we 21 wanted, if we decide that we wanted to do that.
22 If we can go on to the next slide, please, 23 on some specifics.
24 You know, I just wanted to make a comment.
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98 But I think that the way technical adequacy is talked 1
about versus technical accept -- PRA's acceptability, 2
I think the differences are a bit more profound than 3
indicated in the Reg Guide.
4 PRA technical adequacy is basically based 5
on a consensus international standard that the NRC 6
participates in. PRA acceptability is really reflects 7
the position of one regulatory body for regulatory 8
applications. I think they're rather fundamental 9
differences in those terms. So, the suggestion that 10 they're semi-synonymous I think is a little bit 11 misleading.
12 There's, you know, in replaying what's in 13 the non-light water reactor standard some of the 14 paraphrasing is inaccurate. Table 1 really is better 15 represented by Table 1.4-1 in the standard.
16 So, the purpose of paraphrasing things and 17 then leaving things out is a little bit unclear to me.
18 I just wanted to also clarify that with 19 regard to the Figure 1 triangle figure in the Reg 20 Guide, you know, the technical requirements for peer 21 review are actually part of the standard. You can't 22 really meet the standard fully without meeting the 23 technical requirements for the peer review. Whereas, 24 the NEI guidelines is a guidance for how to do the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
99 standard.
1 We try to leave the standard for what to 2
do rather than how we do it. So, just wanted to 3
clarify that.
4 In the paraphrasing --
5 MEMBER BLEY: Could you take another 6
comment? Let me sneak another one in.
7 MR. FLEMING: Please, yes.
8 MEMBER BLEY: Yeah. As I study the staff's 9
clarifications and qualifications, for I would say 90 10 percent of them I think if I were reading the standard 11 I would expect what they said. And I, you know, it 12 really is at this point it's them clarifying what one 13 needs to deliver to them for them to be satisfied that 14 the standard's met for most all of the comments.
15 That's my opinion.
16 MR. FLEMING: Yeah. And I think what, as 17 long as that's understood, I think that's well taken, 18 the point's well taken. And that's why if I were, if 19 I were doing the Reg Guide, if I were working on the 20 Reg Guide I
would try to not express the 21 clarifications in the form of a markup.
22 I just think it's -- it seems to suggest 23 that we need to go back and change the standard right 24 away. And we're not going to be able to do that for 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
100 some time, which I'll get to in a second.
1 So, you know, in the paraphrasing up in 2
C.3, C.1.3 and C.1.4, you know, for example the 3
material on plant operating states and mechanistic 4
source terms and other kinds of things that are in 5
there don't really seem to bring out a very, very 6
important distinction there in the standard is that 7
the event sequences are expected to characterize event 8
sequences that may involve multiple reactors or 9
multiple sources. And that doesn't seem to be 10 emphasized there much.
11 For some reason the Reg Guide looks at 12 documentation just as one section at the end, whereas, 13 we have very specific documentation requirements for 14 each of the technical elements. So, that's a little 15
-- the bottom line is that if someone didn't go 16 through the standard and looked at the front matter in 17 the Reg Guide to get an idea what's in the standard I 18 don't think they get a very good appreciation of 19 what's in the standard.
20 And I'm a little bit sensitive to that 21 because I was involved in leading the group that 22 developed the standard.
23 On the two comments or clarifications that 24 were made on risk integration where the staff has 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
101 deferred their commentary on that to specific 1
applications, I just wanted to say that we believe 2
that these are more fundamental issues. The reporting 3
requirements A.4 and A.5, A.4 talks about, you know, 4
reporting low frequency events, and A.5 comes talks 5
about radiological consequences that are really not 6
that significant because they're, you know, way less 7
than background radiation effects.
8 And we think that these are pretty 9
fundamental. And these come from feedback we got from 10 our pilot studies, especially the pilot study on 11 PRISM, where, you know, the direct application of the 12 trial use standard that we had led them to calculation 13 10 to the minus, you know, umpty-scrump frequencies 14 and, you know, 10 to the minus 27 latent cancer 15 fatalities and so forth. And so we put that in there 16 but recognize the limitations of PRA technology.
17 And I want to go back to something that I 18 know Dennis was in the room several times when Norm 19 Rasmussen would come to PLG when he was on the board 20 of directors. And I heard Norm say at least four or 21 five times that the biggest mistake he made when he 22 published the results of WASH-1400, the Reactor Safety 23 Study, is agreeing to put numbers in there, the curves 24 down there that went all the way down to 10 to the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
102 minus 9 per reactor year. So, that was way beyond the 1
limit, capabilities of PRA technology.
2 So, I think that we believe that those 3
reporting requirements are, you know, important 4
recognitions that PRA technology is limited. And I 5
think that would be true for any application. And my 6
colleague Dennis Henneke has some more specific 7
comments on the specific, you know, clarifications and 8
findings in Appendix A.
9 I have one slide remaining before I turn 10 it over to Dennis on the plans for future changes.
11 So, per direction from the standard 12 writing organization, the standard organization, Jason 13 Ramm, our schedule for the next addition has some 14 constraints on it. We need to wait until all the 15 supporting LWR standards are in alignment with the 16 next edition, which has recently been balloted, and 17 hasn't even been published yet. And I know when the 18 next edition of the LWR standard is published there 19 will be, there will be editorial revisions, you know, 20 made during that process.
21 So, the low power shutdown standard, the 22 Level 2 standard, Level 3 standard, and the advanced 23 LWR standard, and more recently we've started a multi-24 unit PRA standard for light water reactors, all of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
103 those standards really need to be taken to the level 1
where they're in agreement with the next edition of 2
the LWR standard before we can even start.
3 MEMBER BLEY: Karl.
4 MR. FLEMING: Yeah. Yes?
5 MEMBER BLEY: If you can, if you can say a 6
little more about the multi-unit one, I think the 7
committee would be very interested.
8 And the second part is are you considering 9
or do you even think it would be necessary if the 10 staff goes ahead with its initiative for graded PRA to 11 have a standard that addresses possible approaches 12 there?
13 MR. FLEMING: Right. Okay, so the multi-14 unit, there was a -- there's a lot of background here, 15 but we included multi-unit PRA requirements in the 16 non-light water reactor standard. And we also at one 17 time had planned on having a non-mandatory appendix to 18 the light water reactor standard that addressed multi-19 unit issues. This is one of the things that we 20 decided to do after the Fukushima accident.
21 And there was some controversy and some of 22 the members with Jason Ramm were a little bit nervous 23 about that. I guess there was a concern that if they 24 put that out there then they'll be required to do one, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
104 concerns like that that arose.
1 Eventually the decision was made to launch 2
a writing group to develop a trial use multi-unit PRA 3
standard. And so that there's a working group working 4
on that. And there are a good cross-reference of 5
people. There's people from the NRC staff that are 6
working on the Level 3 PRA project. And the IAEA's 7
involved.
8 So, that, that's working in process. And 9
it has some of the same requirements. I mean, the 10 draft that we have has some of the same types of 11 requirements that we have in the non-light water 12 reactor standard, but it's a work in process right 13 now.
14 But if there are new multi-unit issues or 15 requirements that come up in that effort, we certainly 16 want to recommend to account in the next edition of 17 the non-light water reactor standard.
18 But the second big bullet on this slide I 19 wanted to make a comment is that several years ago we, 20 all the input that we needed from the non-light water 21 reactor pilots, we had a lot of pilot studies that 22 were based on the trial use non-light water reactor 23 standard. And the lessons learned from those were 24 pretty incorporated into the preparation of this 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
105 standard a couple years ago.
1 So, the last couple of years most of the 2
resources, and a tremendous amount of resources had to 3
go into this thing to result in some 500 pages after 4
it had been focused down to a PDF file, the vast 5
majority of our work has been to get language 6
alignment with the LWR standards.
7 And the problem has been is that we put 8
this one ahead of the next edition schedule, so we had 9
to work real hard to get, you know, to adapt to all 10 those changes.
11 But the one thing that we need to consider 12 very, very seriously in the next edition is that we 13 need to give the non-light water reactor standard some 14 opportunity to use this standard in their ongoing 15 applications. There's a lot of users out there using 16 this standard today, but there's lots of parts of this 17 standard that haven't been exercised very much.
18 So, we need to think in terms of giving 19 the non-light water reactor community an opportunity 20 to see what their needs are so this thing isn't just 21 driven by LWR alignment issues like it's been for the 22 last two years.
23 So, we don't know what the schedule is.
24 It's going to be a while before the next edition of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
106 the standard comes out. And we can't schedule it in 1
the non-light water reactor writing group because we 2
don't know when these other prerequisites are going to 3
be satisfied. It's probably going to be several 4
years, I would guess.
5 As far as the, as far as the graded PRA 6
applications are concerned, this standard could be 7
useful to support some of those applications. But we 8
did not specifically design the standard to support 9
any of the ideas that are out there about graded PRA 10 applications.
11 I don't know whether there's a good single 12 definition of what that is. I think there's a lot of 13 different ideas about how to, how to grade a PRA. But 14 I would like to say that with regard to the pros and 15 cons of doing PRA for simple reactors or whatever, I 16 think we're stuck. You know, because we've aligned 17 ourselves with the LWR standards, we end up with a big 18 monster of a 500-page set of technical requirements.
19 Most of the size of that standard is driven by the 20 number of requirements that have come in from the LWR 21 world.
22 However, I do believe, and I, you know, 23 the work I've been doing to support some of the 24 modular HTGR concepts that are out there, that the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
107 scope and level of detail of a PRA that meets the 1
standard is really completely correlated to the level 2
of detail and complexity of the plant.
3 And while there's a big document out there 4
that is maybe burdensome to apply to support your PRA, 5
you don't necessarily end up with a very large PRA 6
model itself. And that's why we wrote the event 7
sequence requirements in the standard to go all the 8
way from initiating events to -- with one event 9
sequence model that goes all the way to radiological 10 consequences.
11 So, anyway, I don't think you necessarily 12 have to have a big, multiplied, you know, bookshelf 13 PRA document to meet the standard. If you have a 14 simple reactor, the PRA model should be simple.
15 So, that's pretty much all I had to say 16 here today. And I wanted to leave time for Dennis to 17 fill in some more specifics.
18 MEMBER PETTI: Okay, thanks.
19 I know we're running late and we need to 20 allow public comment and other members. So, Dennis, 21 I see there's about ten slides left between yours and 22 the closing remarks. So, let's see if we can, you 23 know, get done by 45 after or 50 after the hour.
24 MR. HENNEKE: Okay. Yeah, we'll give it a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
108 shot.
1 I'm Dennis Henneke. Many of you know me.
2 I'm the American Nuclear Society Chair for JCNRM, 3
which develops and maintains all the standards that 4
Karl has talked about.
5 We have not gotten formal feedback from 6
the JCNRM, so I'm not representing the JCNRM or GE or 7
any others, it's just my feedback on my initial review 8
of the standard. And, particularly, I'm going to 9
focus on Appendix Alpha of the Reg Guide, Reg Guide 10 1.247.
11 Go to the next slide.
12 This, this Reg Guide and as well as Reg 13 Guide 1.200 is very important, and particularly 14 Appendix Alpha. Those who haven't done a peer review 15 for PRA, now the peer review team goes in to review 16 the
- PRA, taking into account the standard 17 requirements, as well as the exception, NRC exceptions 18 and the wording in the appendix. All the front matter 19 to the regulatory guide is really not reviewed during 20 the peer review. It is, it is the requirements of the 21 standard and the exceptions.
22 And, so, we measured the PRA attributes --
23 which were, Hanh talked about those earlier with 24 regard to the overall technical acceptability --
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109 against those requirements and exceptions. And so, 1
the exceptions become very important. There is as if 2
they were written in the original peer review 3
standard. We do not treat them any differently than 4
whether the wording was written by the consensus 5
group, the consensus standard and JCNRM, or whether 6
the NRC took exception to it.
7 So, it's important that these words be 8
carefully thought out. It's important that the NRC 9
consider this and that the words follow the guidance 10 of the original development of the standard. So, 11 those exceptions really need to be in, all right, 12 similar to the way we would have developed the 13 standard.
14 Generally speaking, we have a couple of --
15 we have some very key guidance in developing standards 16 that come both from ANS and ASME. The main one I'm 17 going to focus on is, I think Vesna mentioned it 18
- earlier, we do not describe any supporting 19 requirements out to the requirements. We try to 20 minimize "how to" guidance.
21 And, in fact, the NRC has for a long time 22 tried to have us remove wording that were too much 23 "how to," and get into the attributes and specify the 24 attributes as in what makes a good PRA.
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110 And then the peer review team looks at 1
what was performed and does it meet -- how the PRA was 2
performed and does it meet the what of the standard.
3 And so, we have worked very hard these last six years 4
to remove all this "how to" guidance, as well as some 5
other things. And that really needs to be considered 6
in the development of the Reg Guide.
7 Let's go to the next slide.
8 I have just a few slides to provide some 9
clarifications. Hanh went through some of this.
10 Overall I would say that we disagree, I disagree with 11 about half of the clarifications. The disagreement 12 really come in the "how to," as well as some things of 13 relatively inappropriate for the regulatory guide, and 14 that you'll, you'll see here in a moment.
15 Some of them are simple. Like the first 16 one, POS-A8 describes, has changed the pre-operational 17 design phase PRA to require an operations review. We 18 don't have operations personnel in the CP stage. We 19 wrote the words very carefully to allow the design 20 review during that phase. But NRC exception requires 21 an operations person, even though we don't have 22 operational personnel. And we would disagree with 23 having that change.
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111 state requiring plant operational state definitions to 1
include changes in the barriers, propagation pathways, 2
and modifications to fragilities.
3 Now, POSes are a defined term, "plant 4
operational state." This comes from a lot of careful 5
consideration with the consensus standard, so we would 6
disagree on having the NRC redefine what a plant 7
operational state is.
8 In addition, this is another example of 9
just too much "how to" in the requirement, and it 10 really should not be an exception, and those word 11 changes should be changed.
12 Last example here, Hahn had noted that for 13 low power shutdown the NRC changes has now required 14 low power shutdown PRA to be performed at all stages 15 of the licensing process. NRC is welcome to require 16 this, but it doesn't belong in the standard.
17 The standard requires you to define what 18 your -- whether you've done low power shutdown and 19 what POSes you're covering in your PRA. And then peer 20 review team will perform their peer review based on 21 that scope. But the standard would never require low 22 power shutdown, seismic analysis be done, or, you 23 know, particularly the scope. It just says define it, 24 and then have the peer review perform this review 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
112 against that defined scope.
1 So, we believe that requiring low power 2
shutdown in all stages really needs to go into another 3
document other than the exceptions listed here.
4 Let's go to the next slide, just a couple 5
more examples.
6 The NRC has added some words that got 7
mentioned in Hahn's presentation, which I highlighted 8
here in the human reliability analysis to include --
9 and it's in multiple locations -- words such as "as 10 well as the well-intended post-initiator operator 11 responses to adverse impact." First, again, there's 12 too much "how to." But what this really does is adds 13 to the PRA the analysis of errors of commission.
14 Now, we have specifically not included 15 errors of commission because the PRAs, PRAs performed 16 today don't have a full evaluation of errors of 17 commission. There are places where we do include it, 18 such as spurious operation due to fire, which causes 19 operator actions which may disable system. But an 20 operator error of commission, a random error of 21 commission, we don't have methodology by which we can 22 do that. We don't have a document or a method to 23 analyze that.
24 And this change is a large change in the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
113 overall scope of the PRA, not supported by the 1
consensus group. And we believe it's inappropriate 2
for the Reg Guide to include the errors of commission.
3 In HRD-4 there's a reference to a NUREG 4
0700. We removed all references and supporting 5
requirements and high level requirements per NRC 6
request, actually. And then to add back any reference 7
to the supporting -- to a particular document. It 8
needs to be removed. As a condolence I would note 9
that this won't have a particular one because it ends 10 up looking as if there's only one way to perform that 11 particular analysis, and there is more than one 12 reference guide on how to look at human factor 13 guidelines. So, we would like that to be removed from 14 the requirements.
15 There were a number of comments which we 16 put off to the non-light water reactor standard, as 17 Karl mentioned. One of them was to add to the number 18 of locations to assess the feasibility of a human 19 failure event, with a bunch of other words. And then 20 if it's not feasible, to assign it a one point mode in 21 the PRA. Now, of course it adds too much "how to."
22 But the light water reactor standard looked at that.
23 We've looked at it a number of times. We reject that 24 change as too much "how to."
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114 Human reliability already -- analysis 1
already does this. If the action isn't feasible, we 2
don't credit the PRA. It's that simple. Don't need 3
these words in the standard. It's too much "how to."
4 We rejected this as a consensus body.
5 I'm not sure who in the NRC really wants 6
to add these words in there, but they shouldn't be 7
added in. It doesn't change how we do an HRA, and 8
it's just not needed in the requirements.
9 And then another example, HRD-4 there's 10 some words that are listed there. It's just way too 11 many words and too much "how to" in the requirement.
12 So, these added words don't really change what we do, 13 and it just should be removed.
14 So, next slide.
15 Those are just some examples. I have a 16 backup slide on the next page which provide a bunch of 17 other examples of about half of the NRC exceptions.
18 But we would take exception to the wording. There's 19 too much "how to." We really need to go through the 20 consensus process.
21 We, as Karl mentioned, we are open to 22 feedback. We know the standard's not perfect. We 23 generally accepted about 80 percent of the NRC 24 comments in the past. The standard was approved in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
115 January, taking into account all the NRC comments at 1
that time.
2 But since January, the NRC has found a 3
whole bunch of new comments to make which are now 4
included in Appendix Alpha. We would prefer those 5
comments to come into the next revision which will be 6
in another two or three years rather than come in 7
without JCNRM review and consideration.
8 And so, if they really don't change what's 9
done in the PRA, and they really don't affect things, 10 we would prefer those to be removed from the Reg Guide 11 and sent to the JCNRM for a normal comment process.
12 There are a number of things Hanh has 13 mentioned that went to the light water reactor 14 standard and were reviewed by light water reactor 15 standard group. Those were, a number of those were 16 accepted by the non-light water reactor group. And we 17 have a final publication of that standard available 18 right now in draft. And we hope to have it published 19 by February of next year.
20 Those accepted changes in the light water 21 reactor standard, those are fair game. And we 22 appreciate that those should go into the Reg Guide so 23 NRC can review that, and has till now. And so there 24 were maybe a dozen-and-a-half changes in the light 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
116 water reactor standard that are good changes to have 1
in the Reg Guide. And so we, we take no exception to 2
those at all.
3 Overall, as Hanh mentioned, there weren't 4
any significant gaps in the current standard. A lot 5
of them were just clarifications in the wording. And 6
but so I don't see any issue with what the NRC has 7
pointed out here. It's just the NRC needs to be a 8
little bit more careful in writing the exceptions, 9
taking into account the methods by which we develop 10 standards, not doing too much "how to," and not adding 11 things that have been rejected by either a consensus 12 body in a comment review in the past.
13 That's all I have. If there are questions 14 or comments, I'd appreciate it.
15 MEMBER PETTI: So, Dennis, Vicki has her 16 hand up.
17 Go ahead, Vicki.
18 MEMBER BIER: Thanks. This is just a quick 19 comment which is with regard to errors of commission.
20 The comment was made about it's 21 inappropriate to expect people to analyze random 22 errors of commission. And I just wanted to point out 23 that I don't think anybody is expecting that people 24 would analyze every possible error of commission. But 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
117 even 20, 25 years ago there was already work on 1
identifying which errors of commission were sort of 2
likely or plausible.
3 And I haven't followed closely enough to 4
know how that work has advanced and whether it's to a 5
point that's reasonable to expect in a standard. But 6
I just wanted to make that clarification.
7 MR. HENNEKE: Yeah. And let me say, a 8
standard standardizes current practice, current best 9
practice. So, we have a variation from PRA to PRA.
10 And sometimes some PRAs don't match the best practice.
11 But if somebody's practicing it and we 12 think it's good to include in the standard, we will 13 improve the standard to account for best practice.
14 Currently there is no, there are no PRA 15 methods by which to include errors of commissions.
16 There are studies, and people have looked at it. But 17 with regard to a systematic approach, we're including 18 errors of commission only within those, again, caused 19 by spurious operation that will result in operator 20 actions to shutdown operating systems.
21 Other than that we just don't have an 22 approach out there on what people are using in the 23 PRAs. And so we shouldn't all of a sudden ratchet up 24 the entire industry because some folks think, well, in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
118 the future we should look at errors of commission.
1 MEMBER BIER: Okay, thanks.
2 MEMBER PETTI: Karl, you had a comment?
3 MR. FLEMING: Yeah. I wanted to pick up on 4
something that Dennis said about the -- on the plant 5
operating state case about how it's, you know, sort of 6
driven by the PRA applications.
7 I note that the Reg Guide doesn't seem to 8
have any paraphrasing or coverage of Section 3 in the 9
PRA standard, which is the PRA application process.
10 But in Section 3 of the standard it clearly states 11 that the user will select the scope and level of 12 detail of his PRA to be consistent with the scope and 13 level of detail of his design, as well as what his 14 applications are.
15 So, that sort of gives in standard a lot 16 of flexibility on how the standard could be used.
17 MEMBER PETTI: Okay. Given the time, are 18 you done then, Dennis? We can move back to Donna for 19 closing?
20 MR. HENNEKE: Yes. I am done. And like I 21 said, there's one backup slide just for the NRC's 22 clarification.
23 MEMBER PETTI: Donna, let's keep rolling.
24 MS. WILLIAMS: (Audio interference.)
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
119 MEMBER BROWN: She's breaking up, Dave.
1 MEMBER PETTI: Yeah, I'm having the same 2
problem. It didn't know if it was my end or others.
3 Can people hear Donna?
4 MEMBER BROWN: No, haven't heard a word she 5
said.
6 MEMBER PETTI: Donna, you're not coming 7
through.
8 Can one of her colleagues let her know?
9 MS. WILLIAMS: Okay. Can you hear me now?
10 MEMBER PETTI: That's better. That's 11 better.
12 MS. WILLIAMS: Okay. I think my headset 13 wasn't working properly. I'll just shout into the 14 computer.
15 All right. Yeah, just we're going to 16 consider over the next couple of months is to have to 17 consider the feedback for both ACRS and other 18 stakeholders. Note that we have the full committee 19 meeting in early October, as well as a public meeting 20 on October 20th.
21 The next couple of
- months, 22 October/November, we'll be going to internal review 23 and concurrence here at the NRC, and issue for trial 24 use in December. We expect that some near-term 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
120 applicants will use it for trial use following that.
1 And then we note that the trial period is 2
flexible. The length of it will depend on several 3
factors such as the next version of the standard, all 4
the rulemakings going on in the NRC, and feedback from 5
early use.
6 And then, finally, as we noted earlier, 7
this is as a trial use Reg Guide. There is no formal 8
comment period. However, comments on all published 9
Reg Guides, including this trial use Reg Guide, are 10 encouraged at any time. And the NRC will consider 11 comments and suggestions.
12 We note that the preliminary use was made 13 public, so the stakeholders and public have an 14 opportunity to review that.
15 We also note, we need to provide feedback 16 on the preliminary use at the October 20th meeting, as 17 well as they can send comments in via email to the 18 technical contact listed in the Reg Guide.
19 Once the trial use Reg Guide is published 20 in the Federal Register at the end of the year, it 21 will include information how to submit comments, 22 including through the federal rulemaking website 23 regulations.gov.
24 And we also anticipate several public 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
121 meetings and workshops after the trial use Reg Guide 1
is published to solicit feedback from stakeholders.
2 So, this concludes the staff's 3
presentation. We thank the subcommittee for the 4
opportunity to brief you today, and we look forward to 5
your feedback.
6 MEMBER PETTI: Okay, thank you.
7 Given the late hour, I'd like to go to 8
public comments first. Do we have someone from NEI 9
that wanted to make comment?
10 MS. ANDERSON: Yes. This is Victoria 11 Anderson from NEI. Can you hear me?
12 MEMBER PETTI: Yes. Go ahead.
13 MS. ANDERSON: Excellent.
14 So, I wanted to just give a couple of 15 remarks on behalf of NEI's members and other 16 stakeholders.
17 We really appreciate the rapid staff 18 action to endorse the ASME/ANS PRA standard, and the 19 NEI 2009 peer review guidance. The endorsement of NEI 20 2009 without exception is, in particular, very 21 valuable to end users of these documents, and is the 22 result of strong cooperation between NRC staff and 23 industry.
24 After speaking with some of our members 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
122 who have interest in the ANLWR space, we have some 1
concerns about some of the staff clarifications on the 2
ASME/ANS ANLWR PRA standard. In particular, we are 3
very concerned about the addition of errors of 4
commission in the staff's position. We do plan to 5
discuss these concerns, including that concern, in 6
detail when we meet with the staff during an October 7
20th public meeting.
8 Finally, while this is not the focus of 9
today's meeting, it was mentioned earlier that perhaps 10 this regulatory guide and standard could be the one 11 regulatory guide and standard for all PRAs for all 12 reactor types. On behalf of NEI's members who 13 currently operate reactors, I think we would need to 14 look very carefully at the regulatory implications of 15 that because of the extensive PRA development and peer 16 review work that many operating reactors have already 17 done.
18 So, we would need to make sure that the 19 existing endorsements and existing regulatory guides 20 were not sunset and were still available for licensee 21 use.
22 That concludes my remarks. Thank you.
23 MEMBER PETTI: Thank you.
24 Any other public comment? If you are on 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
123 a phone line, it's Star-6, I believe.
1 (No response.)
2 MEMBER PETTI: Okay. I don't hear 3
anything.
4 Colleagues, given we have 4 minutes left, 5
the last item is whether or not to write a letter. I 6
will just tell you that I have had emails, since 7
Dennis is not with us, and Joy is not with us, both 8
supporting a letter. Not that it would be long, but 9
some of the issues that have come up more as sort of 10 a punchlist to make sure that it's on the record and 11 things aren't forgotten.
12 If there's anyone who thinks we shouldn't 13 write a letter, why don't you speak now.
14 (No response.)
15 MEMBER PETTI: Okay. I'm not hearing 16 anything. Then I will guess I will report back to 17 Dennis that he's on the hook for a letter.
18 And I want to thank everyone. Very 19 useful, very informative. And I've still got to fix 20 my problem with not being able to see the slides.
21 For my colleagues who are having the same 22 problem, I was googling on a Microsoft website. One 23 of them said, You're just stuck. It's a bug and they 24 haven't fixed it. So, go to a different computer was 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
124 the most common response to fix it.
1 So, with that, I guess we will close this 2
session. And I guess I'll see my colleagues back at 3
two o'clock Eastern for our next subcommittee 4
briefing.
5 Thank you all.
6 (Whereupon, at 12:58 p.m. EDT, the above-7 entitled matter was concluded.)
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
Trial Use RG 1.247 Acceptability of Probabilistic Risk Assessment Results for Advanced Non-Light Water Reactor Risk-informed Activities Michelle Gonzalez, RES Anders Gilbertson, RES Hanh Phan, NRR Martin Stutzke, NRR Karl Fleming, JCNRM Dennis Henneke, JCNRM Donna Williams, NRR Briefing for the Advisory Committee on Reactors Safeguards Subcommittee on Future Plant Designs September 20, 2021 1
- 1. Background (Michelle Gonzalez)
- 2. Approach to Developing RG 1.247 (Anders Gilbertson)
- 4. Future Activities/Revision of Non-LWR PRA Standard (Karl Fleming/Dennis Henneke)
- 5. Next Steps and Stakeholder Engagement (Donna Williams) 2 Presentation Outline
=
Background===
=
Background===
- The advanced non-light water reactor (ANLWR) PRA standard (ASME/ANS RA-S-1.4-2013) was issued in 2013 by ASME/ANS for trial use.
- In February 2021, ASME and ANS jointly issued ASME/ANS RA-S-1.4-2021, Probabilistic Risk Assessment Standard for Advanced Non-Light Water Reactor Nuclear Power Plants
- The scope of the standard includes all levels of analysis (i.e. from initiating event to radiological consequence), all hazards and all operating modes (except internal fire PRA for LPSD-types of POSs).
- The requirements in this standard cover PRAs performed during design, pre-operational, and post-operational phases.
4
Background (contd)
- ACRS Subcommittee on Future Plant Designs-November 2, 2020
- Staff discussed the updated endorsement plan and the ballot results
- Updates from last ACRS meeting
- Draft white paper issued January 15, 2021 (ML21015A434)
- Performance of PRA Peer Reviews Using the ASME/ANS Advanced Non-LWR PRA Standard issued May 5, 2021 (NEI 20-09)
- Pre-decisional trial use RG made public September 7, 2021 (ML21246A216) 5
Draft White Paper: Demonstrating the Acceptability of PRA Results Used to Support Advanced Non-LWR Plant Licensing
Purpose:
to provide staff views and perspectives on demonstrating acceptability of PRA results
- Provided early communication to stakeholders on issues to be addressed in RG 1.247
- Public meeting held on February 23, 2021
- Issues not addressed in RG 1.247 will be included in later documents 6
Endorsement of the Non-LWR PRA Standard and NEI 20-09
- Trial use will allow for incorporation of lessons learned from early use and incorporation of ongoing regulatory efforts (10 CFR Part 53)
- Comments accepted throughout the trial use period (Informal comment period)
- Formal comment period to follow after the draft RG is issued
- Peer Review Guidance in NEI 20-09
- Clean endorsement with no exceptions taken 7
Approach to Developing RG 1.247 Anders Gilbertson, RES 8
Topics
- RG 1.247 regulatory paradigm
- RG 1.247 development approach
- Novel staff positions in RG 1.247 9
RG 1.247 Regulatory Paradigm (1 of 2)
- The use of RG 1.247 helps reduce the need for an in-depth review of the PRA (RG 1.200 relates to obviating the need)
- RG 1.247 defines an application more broadly to accommodate design, pre-, and post-operational regulatory activities 10
RG 1.247 Regulatory Paradigm (2 of 2)
- Guidance on NLWR PRA peer review considers that peer reviews are not required (consistent with DC/COL-ISG-028)
- However, RG 1.247 emphasizes the importance and utility of the peer review process and suggests that a pre-application peer review be performed
- Promotes more efficient staff reviews of applications
- With the existing regulations, the staff have greater latitude to request information about an applicants PRA 11
RG 1.247 Development Approach (1 of 2)
- Organization and substance of content in RG 1.247 broadly mimics that of RG 1.200
RG 1.247 Development Approach (2 of 2)
- An information database tool was developed to help identify relationships and analyze differences between related requirements in different PRA standards and staff endorsements
- Applicability of current staff endorsement in RG 1.200 for related LWR PRA standard requirements were cross-checked against the NLWR PRA standard requirements 13
RG 1.247 v. RG 1.200 Comparison (1 of 4)
Some differences:
- RG 1.247 directly relates to meeting regulations
- RG 1.247 provides staff positions on the acceptability of PRA technical aspects for NLWRs that have not previously been provided for LWRs in RG 1.200
- RG 1.247 provides specific guidance on determining risk significance and the use of relative and absolute importance measures 14
RG 1.247 v. RG 1.200 Comparison (2 of 4)
Some differences:
Consistent with the approach in the NLWR PRA standard, RG 1.247 does not use terms such as:
- Level 1, Level 2, or Level 3 PRA RG 1.247 accommodates determining the acceptability of an NLWR PRA for an LMP application Because the staff identified no exceptions for NEI 20-09, the endorsement is only contained in the body of the RG Scope of RG 1.247 PRA elements not addressed in RG 1.200:
- Plant Operating State Analysis for all POSs
- Internal fire PRA for LPSD-types of POSs
- Radiological consequence
- Risk Integration 15
RG 1.247 v. RG 1.200 Comparison (3 of 4)
Some similarities:
16
- Initiating Event Analysis
- Event Sequence Analysis
- Success Criteria Development
- Systems Analysis
- Human Reliability Analysis
- Data Analysis
- Internal Flood PRA
- Internal Fire PRA
- Seismic PRA
- Hazards Screening Analysis
- High Wind PRA
- External Flood PRA
- Other Hazards PRA
- Event Sequence Quantification
- Mechanistic Source Term Analysis
RG 1.247 v. RG 1.200 Comparison (4 of 4)
Some similarities:
- Both include a table of hazards to consider in the development of a PRA
- Both provide guidance to applicants and licensees on:
- What is an acceptable PRA (Section C.1)
- The use of voluntary consensus standards and an acceptable peer review process (Section C.2)
- How to demonstrate acceptability of PRA for an application (Section C.3)
- PRA documentation needed to support a regulatory decision (Section C.4) 17
Novel Staff Positions in RG 1.247 (1 of 5)
- Plant Operating State Analysis for all POSs
- (Section C.1.3.1)
- Internal fire PRA for LPSD-types of POSs
- (Section C.1.3.9)
- Radiological consequence
- (Section C.1.3.17)
- Risk integration
- (Section C.1.3.18) 18
Novel Staff Positions in RG 1.247 (2 of 5):
Plant Operating States Analysis, all POSs
- Considers that there may be more than one type of at-power POS (e.g., online refueling)
- Staff position accounts for the potential need for a similar staff position for LWRs 19
Novel Staff Positions in RG 1.247 (3 of 5):
Internal Fire PRA, LPSD-Types of POSs
- No analogous staff positions for LWRs
- The NLWR PRA standard does not provide related requirements; as such, acceptability is measured against the staff position in Section C.1.3.9 of RG 1.247
- Staff position accounts for the potential need for a similar staff position for LWRs
- NRC initiating a research project to develop guidance 20
Novel Staff Positions in RG 1.247 (4 of 5):
Radiological Consequence
- An LMP application evaluates frequency and radiological consequence risk
- Outside of LMP applications, there are no regulatory requirements to perform a PRA that assesses consequence risk
- However, it is still important to meet Commission expectations as expressed in various policy statements
- Risk surrogates used for NLWRs will need to be justified 21
Novel Staff Positions in RG 1.247 (5 of 5):
Risk Integration
- No staff position on risk integration has previously been promulgated
- Basis for staff position relates to meeting Commission expectations, as expressed in the Advanced Reactor Policy Statement, which in turn references the Safety Goal Policy Statement and the importance of meeting the QHOs
- Unless justified, relative risk significance criteria should be used to develop the PRA.
- Staff determination of PRA acceptability does not include consideration of risk reporting thresholds 22
Scope of RG 1.247 and Staff Positions on Non-LWR PRA Standard Hanh Phan, NRR 23
RG 1.247 Guidance RG 1.247 provides guidance, for trial use, in the following four areas:
- 1. Defining the acceptability of a PRA and its results used in support of an application - RG 1.247, Section C.1
- 2. Demonstrating the acceptability of the PRA and its results used in an application - RG 1.247, Section C.3
- 3. Documentation to support a regulatory decision - RG 1.247, Section C.4
- 4. Staffs positions on NLWR PRA standard and industry PRA peer review process - RG 1.247, Section C.2 and Appendix A 24
Technical Reviewers Technical Element NRC Reviewer Plant Operating States Analysis Marie Pohida Initiating Event Analysis Keith Tetter Event Sequence Analysis Keith Tetter Success Criteria Analysis Keith Tetter Systems Analysis Hanh Phan Human Reliability Analysis Jonathan DeJesus Data Analysis Hanh Phan Internal Flood PRA Matt Humberstone Internal Fire PRA JS Hyslop Internal Fire PRA LPSD JS Hyslop Seismic PRA Shilp Vasavada Hazard Screening Analysis Alissa Neuhausen High Winds PRA John Lane External Flooding PRA Shilp Vasavada Other Hazards PRA Alissa Neuhausen Event Sequence Quantification Hanh Phan Mechanistic Source Term Analysis Michelle Hart Radiological Consequence Analysis Keith Compton Risk Integration Susan Cooper Newly Developed Methods Shilp Vasavada Peer Review Hanh Phan 25
NLWR PRA Scope 26 Address all radiological sources at the plant
- Reactor cores
- Spent fuel
- Fuel reprocessing facilities
- Accident scenarios that lead to a radioactive release from multiple radiological sources Address all hazards
- All internal hazards such as, but not limited, to internal initiating events, internal floods, and internal fires
- All external hazards such as, but not limited to, seismic events, external floods, and high wind events Address all plant operating states (e.g., at-power, low-power, shutdown)
NLWR PRA should be a Level 3 PRA
- Develop the frequencies of accident scenarios from the occurrence of an initiating event until the release of radioactive materials to the environment
- Estimate the consequences that result from the release
Applicable Regulations and Applications
- This RG applies to applications for NLWR licensing under 10 CFR Part 50
- Current regulations do not require applicants for Part 50 construction permits or operating licenses to provide PRA-related information
- Rulemaking Incorporation of Lessons Learned from New Reactor Licensing Process (Parts 50 and 52 Licensing Process Alignment), Docket NRC-2009-0196, RIN-3150-AI66
- This RG applies to applications for NLWR licensing under 10 CFR Part 52
- Subpart B - Standard Design Certification (DC)
- Subpart C - Combined License (COL)
- Subpart E - Standard Design Approval (SDA)
- Subpart F - Manufacturing License (ML)
- This RG is coordinated with 10 CFR Part 53 rulemaking effort
- Rulemaking Risk Informed, Technology-Inclusive Regulatory Framework for Advanced Reactors, Docket NRC-2019-0062, RIN 3150-AK31
- Being developed as required by the Nuclear Energy Innovation and Modernization Act (NEIMA) 27
Applicability of RG 1.247 Applies to only stationary NLWRs:
- Reactors that are constructed at a site
- Reactors that are constructed at an offsite facility and subsequently transported and installed at a site
- Does not address PRAs used to assess the risk of transporting NLWRs from an offsite facility to the site
- Does not address mobile reactors, which may be relocated to different sites after initial criticality 28
Technical Elements RG 1.247 endorses the following PRA standard technical elements:
1.
Plant Operating State Analysis 2.
Initiating Event Analysis 3.
Event Sequence Analysis 4.
Success Criteria Development 5.
Systems Analysis 6.
Human Reliability Analysis 7.
Data Analysis 8.
Internal Flood PRA 9.
Internal Fire PRA and ASME/ANS RA-S-1.4-2021:
Definitions and Risk Assessment Application PRA configuration control Peer review Newly Developed Methods
- 10. Seismic PRA
- 11. Hazards Screening Analysis
- 12. High Wind PRA
- 13. External Flooding
- 14. Other Hazards PRA
- 15. Event Sequence Quantification
- 16. Mechanistic Source Term Analysis
- 17. Radiological Consequence Analysis
- 18. Risk Integration 29
Endorsement of Nonmandatory Appendices
- The nonmandatory appendices in ASME/ANS NLWR PRA standard may be binned into two groups:
a) Notes that support the understanding of various SRs, and b) Commentaries
- The NRC staff generally accepts the Notes
- The NRC staff provides no opinion about the Commentaries 30
Capability Categories 31 In general, about 20% of the supporting requirements distinguish between CC-I and CC-II
Section C.1 - Acceptability of a PRA and Its Results Used in Support of an Application
- The staff assesses acceptability of the PRA and its results with respect to:
- PRA scope
- Level of detail
- Conformance with consensus standard PRA elements
- Plant representation of a PRA 32
PRA Acceptability 33 PRA Scope Metrics used to characterize risk Plant operating states (POSs) for which the risk is to be evaluated Causes of initiating events (hazard groups)
PRA Level of Detail Defined in terms of the resolution of the modeling used to represent the behavior and operations of the plant A minimal level of detail is necessary to ensure that the impacts of designed-in dependencies are correctly captured PRA Technical Elements Defined in terms of the fundamental technical analyses needed to develop and quantify the base PRA model for its intended purpose The characteristics and attributes of PRA technical elements define specific requirements that should be met Plant Representation How closely the base PRA represents the plant as it is actually built and operated The PRA should be maintained and upgraded, where necessary, to ensure it represents the as-built and as-operated plant PRA Acceptability
Section C.3 - Demonstrating Acceptability of PRA and Its Results Used in an Application For all applications, the PRA-related information provided in the submittal should:
- Describe the PRAs scope, level of detail, and degree of plant representation
- Demonstrate that the PRA has been developed and used in a technically acceptable manner, including the appropriateness of the assumptions and approximations
- Identify the application-specific acceptance criteria and demonstrate that they have been met 34
Section C.4 - Documentation to Support a Regulatory Decision
- Documentation of the PRA model and the analyses performed should comprise both:
- Archival information (i.e., available for audit or inspection), and
- submittal information (i.e., submitted as part of the risk-informed request)
- Archival PRA documentation may be required on an as-needed basis to facilitate the NRC staffs review of the application 35
Section C. 4 - Documentation (continued)
Archival PRA documentation should include:
- The process used to determine the acceptability of the PRA
- The methodology used to assess the risk of the application
- SSCs, operator actions, and plant operational characteristics affected by the application
- How the cause-effect relationships are mapped onto the PRA elements
- The PRA results that will be used to compare against the applicable acceptance criteria
- The scope of risk contributors (hazard groups and modes of operation) included in the PRA to support the application
- The results of the peer reviews of the PRA, PRA upgrades, and use of NDMs, and the results of F&O independent assessments, the resolution of all of the peer reviews
Section C.4 - Documentation (continued)
Submittal PRA documentation should include:
- Demonstration that the PRA model represents the as-designed, as-to-be-built, and as-to-be-operated plant or the as-built and as-operated plant
- The appropriateness of key assumptions and approximations and sensitivity studies
- The appropriateness of a given portion of the PRA that meets a capability category lower than deemed required for the application under consideration
- The appropriateness of PRA model upgrades, including the use of NDMs, for the application under consideration 37
Section C.2 and Appendix A - Staff Positions on PRA Standard and PRA Peer Review Process
- About 80% of the requirements in the NLRW PRA standard were taken as-is from the set of LWR PRA standards
- First consideration ballot for the ANLWR PRA standard (3/24/20 -
5/26/20)
- NRC staff submitted 489 comments, represented a broad set of staff views and perspectives
- Recirculation ballot for the ANLWR PRA standard (7/23/20 -
8/26/20)
- NRC staff submitted 70 comments, included a mix of proposed technical changes and observations related to regulatory issues 38
Section C.2 and Appendix A - Staff Position on PRA Standard (continued)
The staff position on each requirement in ASME/ANS RA-S-1.4-2021 is categorized as:
- No objection - The staff has no objection to the requirement
- No objection with clarification - The staff has no objection to the requirement. However, certain requirements, as written, are either unclear or ambiguous, and therefore the staff has provided its understanding of these requirements
- No objection subject to the following qualification - The staff has a technical concern with the requirement and has provided a qualification to resolve the concern 39
Rationale for the Staff Positions
- JCNRM did not address during ballot process stating that comment needs to be addressed first in the LWR Level 1/LERF PRA standard
- Regulatory issue
- New issue
- Issue was not adequately addressed during balloting
- Not fully addressed by JCNRM
- Added for consistency with the staffs position in RG 1.200, Rev. 3 40
41 Table Description Clarification Qualification Total A-1 Front Matter 3
2 5
A-2 Plant Operating States 3
5 8
A-3 Initiating Events 0
0 0
A-4 Event Sequences 0
0 0
A-5 Success Criteria 0
0 0
A-6 Systems Analysis 5
0 5
A-7 Human Reliability Analysis 7
4 11 A-8 Data Analysis 0
1 1
A-9 Internal Floods 7
1 8
A-10 Internal Fires 1
0 1
A-11 Seismic 22 6
28 A-12 Hazard Screening 8
1 9
A-13 High Winds 4
2 6
A-14 External Floods 14 1
15 A-15 Other Hazards 10 1
11 A-16 Quantification 0
0 0
A-17 Mechanistic Source Terms 0
0 0
A-18 Radiological Consequences 23 5
28 A-19 Risk Integration 6
2 8
A-20 Configuration Control 0
1 1
A-21 Peer Review 0
0 0
A-22 Newly Developed Methods 1
1 2
Totals 114 33 147 Clarification and Qualification Positions
Substantive Clarifications and Qualifications Group Clarifications Qualifications Total Group 1: Low Power and Shutdown Risk 2
2 4
Group 2: External Hazard Risk 4
2 6
Group 3: Errors of Commission 0
2 2
Group 4: Risk Significance 1
0 1
Group 5: Reporting Requirements 2
2 4
Total 9
8 17 42
Group 1 - Low Power and Shutdown Risk Index No.
Issue Position Resolution 1.1 POS-N-2 All stages of the licensing process should address low power and shutdown-types of evolutions Clarification Early pre-operational stage PRAs are typically limited to at-power PRAs only. All stages of the licensing process should address low power and shutdown-types of evolutions 1.2 POS-N-4 All stages of the licensing process should address low power and shutdown-types of evolutions Clarification Depending on the application, the evolution to be addressed may range from at-power only to all plant operating states outage types. All stages of the licensing process should address low power and shutdown-types of evolutions.
1.3 POS-A1 Limiting the CC-I requirement for POS-A1 only to at-power plant evolutions potentially excludes a significant risk contributor as low-power and shutdown-types of POSs have been shown to have a comparable risk in some cases to at-power POSs. As such, the scope of the CC-I requirement should be the same as the scope of the CC-II requirement to avoid excluding potentially significant contributors to risk.
Qualification CC-I IDENTIFY a representative set of plant evolutions to be analyzed.
INCLUDE, at a minimum, plant evolutions from at-power operations.
See Note POS-N-1, POS-N-2, POS-N-3, POS-N-4 CC-I and CC-II IDENTIFY a representative set of plant evolutions to be analyzed, including refueling outages, other controlled shutdowns, and forced outages.
See Note POS-N-3 1.4 POS-B1 Omitting the condition to ensure that the POS grouping does not impact risk-significant event sequences could significantly impact the results and insights from the PRA. As such, a new requirement is needed for CCI to reflect as much.
Qualification CC-I GROUP plant evolutions into a set of representative evolutions.
ENSURE that (a) the evolutions within a group can be considered similar in terms of the set of plant operating states that they contain; (b) the evolutions are bounded by the worst case impact within the group; (c) the grouping does not impact risk-significant event sequences.
43
Group 2 - External Hazard Risk Index No.
Issue Position Resolution 2.1 SFR-C1 Justification of the selected basis needs to be provided, especially for cases where the basis in an extension or expansion of available information. Note S-N-27 also mentions plant-specific justification which is not reflected in the SR.
Clarification SPECIFY the basis for screening of inherently rugged components justifying the applicability to the plant and site or range of sites identified in SHA-A1.
2.2 SFR-C2 Justification of the selected basis needs to be provided, especially for cases where the basis in an extension or expansion of available information. This comment is also supported by the discussion in Note S-N-28.
Clarification SPECIFY the basis and methodologies established for achieving the fragility thresholds defined in Requirement SPR-B5 justifying the applicability to the plant and site or range of sites identified in SHA-A1.
2.3 HS-A3 The requirement does not address plant-specific hazards, which may not be identified as part of the identification of site-specific or design-specific hazards or hazard groups.
Additionally, note HS-N-5 appears to be applicable to HS-A3 as it directly relates to plant-specific hazards and hazard groups.
Clarification IDENTIFY site-, plant-, or and design-specific unique hazards and hazard groups, as applicable to the stage of the plant lifecycle, not already identified in Requirement HS-A2.
See Notes HS-N3, HS-N-4, HS-N-5.
2.4 WHA-A5 150 mile distance is arbitrary Clarification
- a. meet SCR-3 in Table 1.10-1 by showing that the site is more than 150 miles (approximately 250 km) is sufficiently far away from the nearest tropical cyclone-prone coast to screen out tropical cyclone (hurricane or typhoon) high wind hazards from the probabilistic wind hazard analysis; 44
Group 2 - External Hazard Risk (continued)
Index No.
Issue Position Resolution 2.5 SHA-B5 SHA-B5 does not include consideration of (1) the use of an existing probabilistic SHA for a site and, (2) the impact of an updated catalog on the use of the existing probabilistic SHA. Given the likelihood of using an existing site as the bounding site (see SHA-A1),
the considerations identified above are warranted.
Qualification Add the following to SHA-B5:
If an existing probabilistic SHA is used, DEMONSTRATE that an updated catalog of earthquakes does not make the existing probabilistic SHA unviable.
2.6 HS-B5 The values in RI-A5 referenced in item (f) are presented as reporting values, not screening values. Using the reporting values as screening values could be too permissive in excluding contributors from the PRA as screening using a consequence criterion may not be effectively equivalent to screening using a frequency criterion.
Additionally, this requirement is effectively for qualitative screening, as per SCR-3 in Table 1.10-1 and because item (f) is a quantitative criterion, it should therefore not be included in the list.
Qualification USE SCR-3 in Table 1.10-1 when qualitatively screening out a hazard or hazard group by showing that either:
(a) the hazard or hazard group cannot physically impact the plant or plant operations (e.g., it cannot occur close enough to the plant to affect it);
(b) the hazard or hazard group does not result in a plant trip (manual or automatic) or require a plant shutdown; (c) the hazard or hazard group is included in the definition of another hazard; (d) the hazard or hazard group could not result in worse effects to the plant as another hazard that has a significantly higher frequency; (e) the hazard or hazard group is slow in developing and there is demonstrably sufficient time to eliminate the source of the threat or to provide an adequate response; (f) the hazard or hazard group cannot produce a consequence above the value set in RI-A5.
45
Group 3 - Errors of Commission Index No.
Issue Position Resolution 3.1 HLR-HR-E The scope of high-level requirement (HLR) HR-E does not include errors of commission. See HR-E4 in this table for more details about the basis for this issue.
Qualification A systematic review of relevant available procedures, any past operational events, procedural guidance, and training shall be used to identify the set of post-initiator operator responses required for each of the event sequences, as well as, the well-intended post-initiator operator responses that result in adverse safety impacts.
3.2 HR-E4 HR-E4 does not include errors of commission (EOC). EOCs should be included in the advanced non-light water reactor (LWR) PRA standard for the following reasons: (1) the significant amount of experience in operating LWRs facilitates a consensus between NRC and industry to exclude EOCs from the LWR Level 1/large, early release frequency (LERF) PRA standard; however, there is very little (if any) advanced non-LWR operating experience to allow the consensus to exclude EOCs from the advanced non-LWR PRA standard; (2) it is expected that advanced non-LWRs would rely less on human actions than LWRs, which implies that EOCs would play a more important role in advanced non-LWR PRAs than in LWR Level 1/LERF PRAs; and (3) given that (a) the scope of the advanced non-LWR PRA standard covers what in the LWR world is known as Level 2 PRA and (b) there is no consensus about EOCs in Level 2 PRA, the developers of PRAs for advanced non-LWRs should demonstrate that EOCs are not an issue before eliminating them from consideration.
Qualification Add the following to item to HR-E4:
(c) those well-intended actions performed by control room staff that disable a system, sub-system, or component needed in an event scenario.
46
Group 4 - Risk Significance Index No.
Issue Position Resolution 4.1 RI-N-1 Proper use of relative and absolute risk significance criteria.
Clarification Add this text: The choice between using relative or absolute risk significance criteria to develop a PRA should consider issues such as, but not limited to the following:
The use of absolute risk significance criteria may yield a limited set of risk-significant items that is insufficient for developing risk insights or verifying the PRA model.
Importance measures traditionally used in LWR PRAs to identify relative risk significant items (e.g., FV and RAW) may be inaccurate or misleading when applied to noncoherent logic models (i.e., logic models that contain NOT logic).
A PRA that is developed using absolute risk significance criteria should be revised if relative risk significance criteria are used to support a subsequent application, and vice versa.
The use of risk significance criteria (relative or absolute) should address the entire set of risk metrics computed by the PRA.
47
Group 5: Reporting Requirements Index No.
Issue Position Resolution 5.1 RI-N-3 The staff do not consider reporting requirements when determining the acceptability of a PRA for a given application, such reporting requirements should be provided by the appropriate regulatory authority on an application-specific basis.
Clarification The reporting requirement in RI-A4 does not need to be met to demonstrate PRA acceptability.
5.2 RI-N-4 The staff do not consider reporting requirements when determining the acceptability of a PRA for a given application.
Such reporting requirements should be provided by the appropriate regulatory authority on an application-specific basis.
Clarification The reporting requirement in RI-A5 does not need to be met to demonstrate PRA acceptability.
5.3 RI-A4 The staff do not consider reporting requirements when determining the acceptability of a PRA for a given application.
Such reporting requirements should be provided by the appropriate regulatory authority on an application-specific basis.
Qualification This requirement does not need to be met to demonstrate PRA acceptability.
5.4 RI-A5 The staff do not consider reporting requirements when determining the acceptability of a PRA for a given application.
Such reporting requirements should be provided by the appropriate regulatory authority on an application-specific basis.
Qualification This requirement does not need to be met to demonstrate PRA acceptability.
48
NEI 20-09 PRA Peer Review Guidance
- NRC staff received NEI 20-09, Rev. 0 on June 1, 2020
- Staff reviewed and provided observations during a public meeting on July 22, 2020
- Staff received a revision to NEI 20-09 on August 24, 2020
- Staff provided additional comments during a public meeting on October 26, 2020
- NEI submitted Revision 1 of NEI 20-09 on May 5, 2021 49
NEI 20-09 PRA Peer Review Guidance NEI 20-09, Rev. 1, is based on a related industry PRA peer review guidance document, NEI 17-07, Rev. 2, Performance of PRA Peer Reviews Using the ASME/ANS PRA Standard, as endorsed by RG 1.200, Rev. 3 NEI 20-09 addresses all radiological sources, all hazards, all POSs, and all levels of PRA analysis NEI 20-09 process is applicable for a peer review performed for a PRA representing any stage of plant lifecycle The staff finds that the guidance in NEI 20-09, Rev. 1, is acceptable and thus endorses NEI 20-09, Rev. 1, without exception, in RG 1.247, Section C.2.2 The ASME/ANS NLWR PRA standard contains requirements for the performance of an acceptable peer review process. The staff reviewed the requirements and takes no exceptions to them 50
NEI 20-09 Pilots
- NEI plans to pilot the peer review process
- Staff to observe the pilots
- Observations will enhance the staffs positions in RG 1.247 51
52 NLWR PRA Acceptability Issues (1 of 3)
Ten issues were identified as a result of stakeholder feedback on the draft staff white paper Demonstrating the Acceptability of Probabilistic Risk Assessment Results Used to Support Advanced Non-Light Water Reactor Plant Licensing:
- Draft staff white paper: ML21015A434 dated 1/19/2021
- Public meeting held 2/23/2021 Staff presentation: ML21050A240 Industry presentation: ML21055A732 Meeting summary: ML21069A123 dated 3/17/2021
- Public meeting held 3/30/2021 Staff presentation: ML21085A594 Meeting summary: ML21096A107 dated 4/15/2021 Issue resolution status:
- Addressed in RG 1.247, or
- Being addressed in other staff guidance, or
- Initiating research and developmental activities
53 NLWR PRA Acceptability Issues (2 of 3)
No.
Issue Resolution 1
Provide guidance on initial licensing that addresses all NLWRs (LMP or not LMP)
LMP-based applications:
NEI 21-07 (industry TICAP guidance)
Trial use RG to endorse NEI 21-07 ARCAP roadmap ISG ARCAP-related ISGs on specific topics Non-LMP-based Applications: deferred 2
Provide guidance on graded PRA approaches Working group formed to explore alternatives to PRA that achieve the same underlying purposes 3
Provide guidance on voluntary risk-informed applications (in addition to LMP) that may be part of an initial license application or after the license has been issued NRR/RES work request 4
Address the use of risk surrogates Addressed in RG 1.247 5
Address the use of seismic margins analysis (SMA)
SMA excluded in NLWR PRA standard and, hence, not addressed in RG 1.247 Applicants who seek to use SMA are encouraged to discuss during pre-application interactions
54 NLWR PRA Acceptability Issues (3 of 3)
No.
Issue Resolution 6
Address completeness uncertainty LPSD fires: NRR/RES work request Uncertainty: NRR/RES work request 7
Define the bounding site for external hazards and radiological consequence evaluation Each applicant to propose and justify on a case-by-case basis 8
Address the applicability of supporting requirements (SRs) during various licensing stages Develop ISG 9
Address the use of absolute and relative risk significance criteria Addressed in RG 1.247 10 Use of peer reviews (full-scope and focused-scope) to demonstrate PRA acceptability Addressed in RG 1.247
55 Risk Significance (1 of 3)
Goal: Identify what is important Uses:
- Develop the PRA model
- Increase level of detail and plant representation for risk significant items
- Logic model debugging
- Iterative process
- Report PRA results Two approaches:
- Relative risk significance
- Normalized to total risk
- Traditional PRA approach
- Absolute risk significance
- Normalized to a specified risk target (e.g., LMP frequency-consequence target curve, QHOs)
- Concept evolved as a result of various LMP pilot exercises
56 Risk Significance (2 of 3)
Risk Significant Basic Event Relative A basic event that contributes significantly to baseline risk. It is defined as any basic event that has an Fussell-Vesely (FV) importance greater than 0.005 or a risk achievement worth (RAW) importance greater than 2 where the importance is normalized against the baseline total integrated risk or risk of a specific combination of source of radioactive material, hazard, and plant operating state.
Absolute A basic event that contributes significantly to an absolute risk significance criterion selected for RIDM. It is defined as any basic event that contributes significantly to an absolute risk significance criterion selected for RIDM. It is defined as any basic event that a) contributes at least 1% to any identified absolute risk target; or b) would result in exceeding the criterion if the basic event is assumed to fail with probability of 1.0.
57 Risk Significance (3 of 3)
Risk Significant Event Sequence or Event Sequence Family Relative An event sequence or event sequence family that, when rank-ordered by decreasing frequency, contributes a specified percentage of the baseline risk, or that individually contributes more than a specified percentage of the risk. For this version of the Standard, the aggregate percentage for the set is 95%, and the individual event sequence or event sequence family percentage is 1% of the total integrated risk or risk of a specific combination of source of radioactive material, hazard, and plant operating state.
Absolute An event sequence or event sequence family included in a PRA model, defined at the functional or systematic level, that makes a significant contribution to an absolute risk target selected for RIDM. It is defined as any event sequence or event sequence family that contributes at least 1% to any identified absolute risk target.
PERSONAL COMMENTS ON RG 1.247 Karl N. Fleming Former Chair JCNRM WG on Advanced non-LWRs (Currently Vice Chair) karlfleming@comcast.net
MY PERSONAL COMMENTS The following comments are my personal opinions and do not reflect the official position of the JCNRM or supporting groups and subcommittees 59 ACRS Meeting on RG 1.247
BACKGROUND
- Per NRC request JCNRM prioritized the schedule for this standard ahead of next edition LWR PRA standard
- JCNRM appreciates extensive involvement of NRC staff and NRC contractors in producing the standard and support of Ballot Reviews
- First consideration ballot in May 2020 yielded over 1300 comments including nearly 500 from NRC staff
- Second consideration ballot in July 2020 was unanimously approved by the JCNRM with 86 largely editorial comments mostly from the NRC
- Final editorial changes approved by JCNRM via two unanimous voice votes
- Changes were made to the next edition of LWR standard recently balloted to minimize editorial inconsistencies.
- Given that background I was surprised that the approach taken to express clarifications in the RG was expressed in terms of so many further editorial changes rather than commentary regarding HOW the NRC staff expects the requirements to be addressed for regulatory applications.
GENERAL COMMENT
S
- There are several places that claim that risk characterization for NLWRs is typically expressed by cumulative risk metrics or risk surrogates.
- These statements should be modified to clarify the that fundamental metrics used to formulate the requirements characterize risk in terms of the frequencies and radiological consequences of event sequence families (not individual sequences).
- The NLWR standard does not use the LWR risk metrics CDF or LERF as explained in Section 1.9.1 so not clear why it is suggested as a possibility in the RG.
- The PRA standard does not support the use of surrogate risk metrics as a means of expressing the results of the PRA but only as intermediate states for developing the event sequence model. If such intermediate metrics are used, the standard still expects that risk integration and evaluation of risk significance will be based on quantification of frequencies and consequences.
- Sections C.1.3 and C.1.4 provide a long discussion of objectives and attributes for each of the technical elements in the standard. These discussions overlap extensively with material in the standard that cover the same ground but they are not one for one and it would take a long time to figure out if there is anything different here. Rather than paraphrasing material on objectives and attributes already covered in the standard, the RG should focus on the specific items that the staff wishes to clarify
- Many of the clarifications in Appendix A refer to language shared with LWR supporting standards
- In the clarifications provided in Appendix A, it would be helpful for the staff to point out which changes are for alignment with LWR standard vs. those unique to the NLWR standard ACRS Meeting on RG 1.247 61
SPECIFIC COMMENTS
- Suggestion that PRA technical adequacy are the same as PRA acceptability needs clarification; technical adequacy is based on meeting requirements in an international consensus PRA standard while acceptability expresses a U.S. regulatory position.
- The PRA technical elements presented in Table 1 are not consistent with the ones used in the standard (See Table 1.4-1). The elements listed for internal events are applicable to all internal and external hazard groups. This is one of a number of examples where the RG is paraphrasing material in the standard but in a manner that is not always accurate.
- Should be clarified that the technical requirements for peer review are actually part of the standard and not separate entities as suggested in Figure 1 (Triangle Figure).
- Discussion on POS, MST, and other elements seem to lack appreciation of the need to address the impact of multiple reactors and sources.
- The RG treats documentation in one section whereas standard has documentation requirements specialized for each technical element
- Regarding the staff position on reporting requirements RI-A4(low frequency item) and RI-A5(low consequence item), which defer to specific applications, the authors of the standard believe these are fundamental to recognizing limitations in PRA technology.
- My colleague Dennis Henneke has additional general and specific comments to offer ACRS Meeting on RG 1.247 62
PLANS FOR NEXT REVISION
- Per JCNRM guidance, need to wait until all the supporting LWR standards are revised for consistency with the recently balloted LWR Level 1/LERF Standard
- Low Power Shutdown Standard
- Level 2 Standard
- Level 3 Standard
- Advanced LWR Standard
- Advanced non-LWR community needs to gain sufficient experience using the 2021 edition of the NLWR standard to identify the issues unique to NLWRs and to justify application of standard writing resources.
Review of Draft RG 1.247 Appendix A - NRC Position on ASME/ANA RA-S-1.4-2021 Dennis Henneke Consulting Engineer - GE Hitachi JCNRM ANS Chair*
- Not representing ANS or the JCNRM for this presentation.
64
Overview of ASME/ANS PRA Standard Requirements
- The Joint Committee on Nuclear Risk Management (JCNRM) develops and maintains PRA standards for LWRs and NLWRs using a consensus committee made up of all stakeholders including the NRC and its contractors.
- The NRC provided hundreds of comments on RA-S-1.4-2021, the vast majority were accepted.
- PRA Standards for existing LWRs (draft 2021) and NLWRs (RA-S-1.4-2021) define the following to determine a technically acceptable PRA:
- Scope: This includes the hazards (internal events, internal hazards and external hazards) and the plant operational states (full power, low power and shutdown) for each hazard.
- PRA Attributes: as defined by the High Level Requirements (HLRs) and Supporting Requirements (SRs). HLRs are in the form of Shall statements and SRs support the HLRs.
Content of HLRs and SRs are prescribed by the ASME and ANS guidance.
- The PRA standard SRs define what is required (performance-based) to meet the HLRs but should not describe how to meet the requirement or limit the approach to a single methodology by referencing a document in an SR.
- The NRC and JCNRM members have provided numerous comments on removing wording from the SRs that were too much how to perform the PRAs.
65
Feedback on NRC Clarifications
- The standard has undergone numerous rounds of review including in 2020, and the resulting standard is a consensus product. Many of the NRC clarifications have either gone through consensus review or should go through consensus review for determination of technical correctness:
- POS-A8: the addition of requiring review of POSs identification by operations personnel prior to plant operations (in design) - when we will not necessarily have operations personnel.
- POS-A10: The clarification requires POS definitions to include changes in barriers, propagation pathways and modification of fragilities in the POS definitions.
- This both disagrees with the definition of POS and is too much how to in the SR.
- Changes such as this are addressed in the PRA modeling, not POS definition.
- POS-A1 and Note POS-N-2: Clarification is requiring LPSD to be included at All stages of the Licensing Process.
- Disagrees with the discussion throughout the standard and the consensus wording of POS-A1.
- The standard is not a licensing document and should not discuss what is required at various stages of licensing.
66
Feedback on NRC Clarifications
- HLR-HR-E; Added words to the HLR: A systematic review shall be used to identify post-initiator operator responses as well as, the well-intended post-initiator operator responses that result in adverse safety impacts
- Too much how to in the HLR.
- When combined with changes to HR-E4 (actions that disable a system); the changes now require additional analysis of errors of commission, not currently required by any PRA standard.
- HR-D4: Adds reference to NUREG-0700 for adherence to human factors guidelines
- Again, too much how to.
- Additionally, reference to a specific document in the SR is not appropriate, since this indicates only one acceptable approach to meet the SR.
- HR-G1: Adds to the requirement wording to ASSESS the feasibility of the HFE.;
ASSIGN an HEP of 1.0 if not feasible.
- Again, too much how to.
- A similar change was rejected by the JCNRM previously for the above reasons.
- HR-G4: Adds the wording: in supporting the decision, diagnosis, decision-making and action execution given the plant-specific and event scenario-specific contextcommunication among personnel in the same team and in different teams.
- Again, too much how to 67
Feedback on NRC Clarifications
- JCNRM standard are not perfect, and we welcome feedback and improvements through the consensus process.
- Generally, we try to accommodate most comments through change in the standard wording.
- Some of the NRC exceptions were changes incorporated into the LWR draft in publication (no objection to these).
- RG 1.247 exceptions do not point to any significant gaps in the NLWR standard.
- The previous examples above are just a few examples where the draft RG should be improved (see backup slide for more examples):
- Overall, these types of changes should be submitted to the JCNRM NLWR working group for review and consideration to ensure the standard SRs are correctly worded and supported by consensus review.
- Any NRC recommended changes to the standard wording should be consistent with standard development guidance:
- Wording should focus on what is required versus how to perform the PRA.
- HLRs and SRs should not reference specific documents or limit the approach to one approach.
- The standard should not dictate what scope is required at different phases of licensing.
68
DWH Backup
- Other NRC clarifications which should be reviewed:
- HR-G14 (to much how to shown in blue), HR-H2, DA-C20, FLEV-C1 (1st mention of temp. alignments - under documentation), SHA-B5, SHA-D3, SFR-C1, C2, SFR-D5 (no other mention of pathways), SFR-E3, E4, E5, E7 (wording is too limiting), HLR-SPR-B, SPR-B6 (expands the relay chatter from Risk-Significant SSCs to all SSCs), SPR-D6 (see previous feasibility comment), SPR-E8 (and/or not appropriate), HS-A3 (hazards are not applicable to a design stage), HS-B5 (change should be reviewed by JCNRM in brown), WFR-I1 (fix the bullet numbers), WPR-D11 (see previous feasibility comment),
XFPR-E6, OPR-A4, OPR-C6 (feasibility), RCRE-A2, RCPA-A3, RCPA-A10, RCME-A2/4/7/8 (also refers to RG 1.23), RCME-A3, RCAD-A5, RCAD-B2, C1, RCDO-A and A1/6 (skin absorption not previously mentioned in the standard), RCDO-A8, RCQ-A3, RCQ-B3 (results of interest inaccurate).
- Notes not reviewed for this presentation.
69
Next Steps and Stakeholder Engagement Donna Williams, NRR 70
Next Steps
- Consider feedback from ACRS/other stakeholders (September
- mid-October)
- Public meeting October 20, 2021
- NRC concurrence and trial use RG publication - October -
November
- Issue for trial use - December 2021
- Initial use by near-term applicants
- Trial use period is flexible, depending on timing of the next version of standard, rulemakings, and feedback from early use 57
Comments and Feedback
- Comments and improvements on all published RGs including this trial use RG are encouraged at any time and the NRC will ensure consideration of such comments and suggestions.
- Preliminary trial use RG made public - September 7, 2021
- October 20, 2021-public meeting
- Public meetings/workshops to discuss feedback from first uses 72
Acronyms ANLWR - advanced non-light water reactor ANS - American Nuclear Society ASME - American Society of Mechanical Engineers CFR - Code of Federal Regulations COL - combined license CP - construction permit DC - design certification ISG - interim staff guidance JCNRM - Joint Committee on Nuclear Risk Management LMP - licensing modernization project LPSD - low-power and shutdown LWR - light-water reactor NEI - Nuclear Energy Institute NRC - Nuclear Regulatory Commission NRR - Office of Nuclear Reactor Regulation OGC - Office of the General Counsel OL - operating license QHO - quantitative health objective POS - plant operating state PRA - probabilistic risk assessment RES - Office of Nuclear Regulatory Research RG - regulatory guide SC - subcommittee SSC - structures, systems and components SP - staff position SR - supporting requirement SSC - structure, system, and component 73
General Framework for PRA Acceptability 74