ML23248A347

Transcript of Advisory Committee on Reactor Safeguards - Fuels, Materials, and Structure - DANU-ISG-2023-01 Subcommittee Meeting, August 23, 2023, Pages 1-65 (Open)

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Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION

Title:

Advisory Committee on Reactor Safeguards Fuels, Materials, and Structures Docket Number:

(n/a)

Location:

teleconference Date:

Wednesday, August 23, 2023 Work Order No.:

NRC-2511 Pages 1-41 NEAL R. GROSS AND CO., INC.

Court Reporters and Transcribers 1716 14th Street, N.W.

Washington, D.C. 20009 (202) 234-4433

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(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com 1

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 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 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION

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ADVISORY COMMITTEE ON REACTOR SAFEGUARDS (ACRS)

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FUELS, MATERIALS, AND STRUCTURES SUBCOMMITTEE

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WEDNESDAY AUGUST 23, 2023

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The Subcommittee met in a hybrid meeting, in-person and video-teleconference, at 1:00 p.m. EDT, Ronald Ballinger, Chairman, presiding.

COMMITTEE MEMBERS:

RONALD G. BALLINGER, Chairman VICKI BIER, Member CHARLES H. BROWN, JR., Member VESNA DIMITRIJEVIC, Member GREGORY HALNON, Member WALT KIRCHNER, Member JOSE MARCH-LEUBA, Member DAVID PETTI, Member JOY L. REMPE, Member

2 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 THOMAS ROBERTS, Member MATTHEW SUNSERI, Member ACRS CONSULTANTS:

DENNIS BLEY STEPHEN SCHULTZ DESIGNATED FEDERAL OFFICIAL:

CHRISTOPHER BROWN ALSO PRESENT:

MEG AUDRAIN, NRR ALEX CHERESKIN, NRR MATTHEW GORDON, NRR SCOTT MOORE, ACRS REBECCA OBER, NSIR GREG OBERSON, NRR DAVID RUDLAND, NRR

3 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 TABLE OF CONTENTS Opening Remarks and Objectives 4

Staff Opening Remarks 7

Discussion of ISG and Public Comments 8

Public Comments 38 Committee Discussion 38 Adjourn 41

1 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 P-R-O-C-E-E-D-I-N-G-S 1

(1:00 p.m.)

2 CHAIRMAN BALLINGER: The meeting will now 3

come to order. This is a meeting of the Fuels, 4

Materials, and Structures Subcommittee of the Advisory 5

Committee on Reactor Safeguards.

6 Im Ron Ballinger, chairman of todays 7

subcommittee meeting. ACRS members in attendance are 8

Charles Brown, Greg Halnon, Vicki Bier, Joy Rempe, Dave 9

Petti, Matthew Sunseri, Jose March-Leuba, and Tom.

10 And online I think --

11 MEMBER REMPE: Tom Roberts, just to help 12 you.

13 (Laughter.)

14 CHAIRMAN BALLINGER: I know. Tom 15 Roberts. I know.

16 And online, I think, are Vesna -- is Vesna 17 there? Vesna --

18 MEMBER DIMITRIJEVIC: I am there. I am 19 here.

20 CHAIRMAN BALLINGER: Thank you very much.

21 And I think thats it. Oh, is Walt -- I dont see 22

-- well --

23 PARTICIPANT: He will be joining us 24 shortly.

25

2 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 CHAIRMAN BALLINGER: Yeah. I dont see 1

-- oh, wait a minute. Well, I dont know how to tell 2

whether hes on or not. Anyway, Walt Kirchner will 3

join us.

4 We have our consultants, Steve Schultz and 5

I assume Dennis Bley. Very good. If I have missed 6

somebody, I apologize.

7 Chris Brown, who is also online, of the 8

ACRS staff is the Designated Federal Official for this 9

meeting.

10 During todays meeting, the subcommittee 11 will receive a briefing on the staffs draft 12 EANU-ISG2023-1 material compatibility for non 13 light-water reactors. The subcommittee will hear 14 presentations by, and hold discussions with, the NRC 15 staff -- thank you very much -- and other interested 16 persons regarding this matter as may happen.

17 The rules for participation in all ACRS 18 meetings were announced in the Federal Register on June 19 13th, 2019. A U.S. NRC public website provides the 20 ACRS charter, bylaws, agendas, letter reports, and full 21 transcripts of all full and subcommittee meetings, 22 including slides.

23 The agenda for this meeting was posted 24 there, along with the MS Teams link. We have received 25

3 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 no written statements or requests to make an oral 1

statement from the public.

2 The subcommittee will gather information, 3

analyze relevant issues and facts, and formulate 4

proposed positions and actions, as appropriate, for 5

deliberation by the subcommittee.

6 A transcript of this meeting is being kept 7

and will be made available. Todays meeting is being 8

held in person over Microsoft Teams -- and over 9

Microsoft. Sorry. There is also a telephone bridge 10 line and an MS Teams link allowing participation by 11 the public.

12 When addressing the subcommittee, the 13 participants should first identify themselves and speak 14 with sufficient clarity and volume that they may be 15 readily heard. When not speaking, we request that 16 participants mute your computer microphone or phone 17 by pressing star-six.

18 I might add that for those of you who have 19 not been in meetings here, these microphones are very 20 direction -- directional, and you have to almost swallow 21 the thing. You have to get very close to it, and its 22 important for the -- for the court reporter.

23 We will now proceed with the meeting, and 24 Id like to start by calling Greg Oberson -- yes, he 25

4 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 is -- Branch Chief in NRR for opening remarks.

1 Excuse me. Before we get started, the 2

reason for this meeting is we are starting to receive 3

applications and having presentations for a lot of 4

non-light-water reactor designs. And this ISG is a 5

complement to other documents which the staff put 6

together to identify critical materials compatibility 7

issues related -- that would relate to these 8

non-light-water reactor designs.

9 All of the designers have to -- have to 10 adhere to ASME Code and other standards. But related 11 to materials compatibility with respect to corrosion 12 and other kinds of things, a lot of these codes and 13 standards basically say youre on your own. And so 14 this ISG is helpful or will be helpful in that -- in 15 that area.

16 So, Greg, sorry I interrupted you.

17 MR.

OBERSON:

Good afternoon, Dr.

18 Ballinger and members. Thank you for the opportunity 19 to present to the subcommittee this afternoon. Im 20 the branch chief for Technical Branch I in the Division 21 of Advanced Reactors and Non Power Production and 22 Utilization Facilities in the Office of Nuclear 23 Regulatory Research.

24 As you already alluded to, our staff are 25

5 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 currently reviewing two applications for 1

non-light-water reactors, the Kairos Hermes Test 2

Reactor and the Abilene Christian University Molten 3

Salt Research Reactor, while also the acceptance review 4

is ongoing for the Kairos Hermes 2.0 test reactor, and 5

three or more applications for commercial 6

non-light-water reactors are anticipated within the 7

next year to two years.

8 I begin with this to highlight the 9

increasing workload for NRC staff on the 10 non-light-water reactor licensing. And with that 11 context, to emphasize the importance of clear, sound 12 guidance that can be referenced by staff to support 13 efficient and effective licensing processes.

14 Today we will present to you on one such 15 example; namely, the Interim Staff Guidance, or ISG, 16 on materials compatibility for non-light-water 17 reactors. The ISG reflects differences in the 18 materials fabrication methods, operating environments 19 that will fundamentally distinguish component 20 integrity and evaluations for non-light-water reactors 21 from those from large light water reactors for which 22 staff have abundant experience.

23 Youll hear further from the staff on the 24 purpose, scope, and content of the ISG. A draft of 25

6 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 the ISG was issued for public comment in March of this 1

year, and we will also discuss how the comments were 2

addressed to prepare the final Interim Staff Guidance.

3 Finally, Id like to acknowledge that the 4

ISG was a collaborative effort. And in addition to 5

my colleagues at the table presenting to you today, 6

key contributions were made by additional staff in NRR 7

as well as in the Office of Nuclear Regulatory Research.

8 We look forward to todays discussion.

9 And with that, Ill pass it back to you, 10 Dr. Ballinger. Thank you.

11 CHAIRMAN BALLINGER: Thank you.

12 So Im still not sure who is controlling 13 the slides, but theyre up there, so -- very good.

14 Okay. So proceed, please. Im not sure who the 15 presenters are, but you might introduce yourself.

16 MS. AUDRAIN: Good afternoon. Am I close 17 enough to the microphone?

18 CHAIRMAN BALLINGER: Youre not that --

19 youre not close enough.

20 MS. AUDRAIN: Okay. Is that better?

21 CHAIRMAN BALLINGER: Youve really got to 22 23 MS. AUDRAIN: Good afternoon. I am Meg 24 Audrain, and Im here today with Alex Chereskin and 25

7 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 Matt Gordon, as well as other members of the working 1

group, both in person and online. We are presenting 2

today on the ISG that we developed for materials 3

compatibility in advanced reactor environments.

4 Today we are going to be going over the 5

purpose and applicability of the ISG, the regulatory 6

framework, qualification and performance monitoring, 7

the technical content of the ISG, and our public comment 8

and resolution, or our public comment resolution.

9 Next slide. We developed this ISG to 10 assist staff in reviewing applications for construction 11 and operation of non-light-water reactor designs, 12 including power and non-power reactors. The guidance 13 in this document identifies areas of staff review that 14 could be necessary for a submittal seeking to use 15 materials allowed under ASME Section III, Div 5.

16 Staff expects that most applicants will 17 demonstrate their materials meet Div 5, which specifies 18 the mechanical properties and allowable stresses to 19 use for design of components in high temperature 20 reactors. However, as stated in Div 5, code rules do 21 not provide methods to evaluate and service 22 deterioration caused by the environment, such as 23 corrosion or radiation effects, but do state that these 24 effects should be taken into account for the design 25

8 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 or component life.

1 This ISG provides the staff guidance in 2

reviewing material areas that are not covered by Div 3

5. It identifies information the staff should consider 4

in its review related to materials qualification. It 5

also indicates where monitoring and surveillance may 6

be appropriate to be relied upon to ensure component 7

integrity.

8 Currently, there is no staff guidance on 9

how to review materials qualification, performance 10 monitoring

methods, or surveillance for 11 non-light-water reactors. This guidance is intended 12 to ensure consistency across staff reviews and clarity 13 on what to review in an application.

14 Next slide.

Non-LWRs present 15 environmental challenges to material performance that 16 are not present in LWRs as the operating environments 17 are different than those in our current fleet. The 18 operating temperatures of non-LWRs may be significantly 19 higher than those in current nuclear power plants, where 20 temperature ranges corresponding to the creep regime 21 in which deformation may occur with applied stress.

22 The coolants used in non-LWRs are 23 significantly different from those used in LWRs as well.

24 These coolants may be liquid metals such as sodium 25

9 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 or lead, liquid salts with or without fuel, helium, 1

or possibly other coolants not yet considered. These 2

different coolant environments may increase 3

susceptibility to material corrosion, degradation 4

mechanism, and radiation effects.

5 Studies have identified the gaps in 6

knowledge that exist for some of these coolant types 7

and the impact on the materials being considered in 8

the construction and operation of these non-LWR nuclear 9

power plants. Because of the current state of 10 knowledge of degradation in these environments, and 11 long test time, the staff will place a strong emphasis 12 on ISG, on using mitigation strategies, performance 13 monitoring, and surveillance programs to ensure SSCs 14 continue to satisfy the design criteria where 15 appropriate.

16 Next slide. This ISG is applicable to NRC 17 staff reviews of applications for non-LWR designs, 18 including both power and non-power reactors, for 19 permits, licenses, certifications, and approvals under 20 10 CFR Parts 50 and 52.

21 As stated in the Commissions policy 22 statement on the regulation of advanced reactors, 23 advanced designs are expected to provide enhanced 24 margins of safety; use simplified, inherent, passive, 25

10 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 or other innovative means to accomplish their safety 1

and security functions; or both. Examples of advanced 2

reactors include molten salt reactors, liquid metal 3

reactors, and high temperature gas-cooled reactors.

4 The current regulatory framework for 5

qualification of structural materials in non-LWRs is 6

as follows. The 10 CFR regulations listed on the slide 7

state that applicants must include PDCs for their 8

facilities. Reg Guide 1.232 provides proposed 9

guidance for the development of PDCs for non-LWRs.

10 Several design criteria in this reg guide 11 relate to materials qualification for structural 12 materials and state the importance of environmental 13 compatibility, inspection, material surveillance, and 14 functional testing.

15 Next slide. Before I begin a description 16 of the technical content of the ISG, Im going to define 17 a few terms to make sure everyone has a common 18 understanding.

First, materials qualification 19 includes testing conducted in an environment simulating 20 the anticipated operating environment for the reactor, 21 including chemical environment, temperatures, and 22 radiation.

23 Performance monitoring includes 24 inspections or examinations to confirm adequate 25

11 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 performance and to identify unacceptable degradation.

1 It may also include aging management programs or post 2

service evaluations.

3

And, finally, surveillance programs 4

include examination of test coupons and components 5

removed from the reactor over the licensed operating 6

period.

7 CHAIRMAN BALLINGER:

This is Ron 8

Ballinger. Im going to try to stick this in where 9

I can. I see no -- in this ISG, I think there might 10 have been or might be an opportunity to go after the 11 issue of modeling and simulation as it relates to 12 qualification of materials.

13 Over the years, modeling and simulation, 14 especially in the materials area, has turned -- has 15 really, really expanded. We oftentimes hear we want 16 it to be a prototype, and things like that, and thats 17 what this kind of performance and qualification 18 monitoring kind of implies.

19 But Im curious as to whether in developing 20 the ISG folks considered somehow addressing the issue 21 of the use of modeling and simulation as part of the 22 overall materials qualification process.

23 Dave has pointed out to me that that was 24 done in the fuels qualification area, but its much 25

12 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 broader. So Im curious as to whether or not there 1

was consideration to including in the ISG something 2

related to how you used modeling and simulation to --

3 I dont want to use the word expand, but enlarge the 4

data set, if you will, in quotes, because thats going 5

to happen. Its inevitable. Were going to see 6

applicants come in and make extensive use of modeling 7

and simulation.

8 MS. AUDRAIN: I dont know that we 9

specifically address that in the ISG. Theres nothing 10 in the ISG that prohibits the use of modeling and 11 simulation.

12 CHAIRMAN BALLINGER: Yeah. Theres 13 nothing in the ISG, thats for sure. Im just saying 14 some -- have you thought -- did you think about including 15 something like that in the ISG?

16 MS. AUDRAIN: So the scope of the ISG is 17 really to focus on environmental impacts and 18 considerations. So I am not entirely sure where we 19 would address modeling and simulation. Do you --

20 CHAIRMAN BALLINGER: So it wasnt part of 21 the plan, is what youre saying.

22 MS. AUDRAIN: Yeah.

23 CHAIRMAN BALLINGER: Okay.

24 MS. AUDRAIN: I think in doing the -- in 25

13 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 doing the review, you know, an applicant would likely 1

propose using modeling and simulation of their data 2

that they gather. So --

3 MR. CHERESKIN: Yeah. I think I would 4

echo what Meg said there. And, in addition, you know, 5

our guidance here I dont think got to the very 6

prescriptive level of this is exactly how you review, 7

you know, specifics for an application like modeling 8

and simulation.

9 But, at the time, you know, if someone 10 proposed it, we would obviously review it, you know, 11 as appropriate, when we get those applications.

12 PARTICIPANT: You needed to state who you 13 were for the court reporter.

14 MR. CHERESKIN: Sorry. This is Alex 15 Chereskin.

16 CHAIRMAN BALLINGER: And Ive got one 17 other question, which I missed because I was writing 18 something down. Did you look at -- with regard to 19 materials and corrosion-related issues, did you look 20 at API-579, which was converted into an ASME Code 21 document, FF -- now Im forgetting -- FFS-1, Fitness 22 for Service, Chapters 7, 8, and 9, and that definitely 23 has guidance on how to include environmental effects.

24 MS. AUDRAIN: Im not sure. I dont 25

14 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 believe that anybody on the staff did.

1 CHAIRMAN BALLINGER: I would encourage you 2

to take a look at that, because now its an ASME Code 3

document. It was an API document before, but the ASME 4

just basically incorporated it and just took the title 5

page off and put ASME on the front. Because 6

environmental effects are a big deal in the oil and 7

gas industries, but that API is not specific necessarily 8

to the oil and gas industry.

9 MS. AUDRAIN: Okay.

10 MEMBER REMPE: So, Ron, just out of 11 curiosity, what would you like them to do to talk about 12

-- interpolation is generally okay if you have data 13 to support something for material qualification. Do 14 you want them to talk about how far you can extrapolate 15 with modeling and simulation and say --

16 CHAIRMAN BALLINGER: I dont want these 17 folks to do it.

18 MEMBER REMPE: No. But you want the ISG 19 to say something about --

20 (Simultaneous speaking.)

21 CHAIRMAN BALLINGER: Im suggesting that 22 there might be ISG-2, or some other number in the future, 23 where this issue of using modeling and simulation as 24 part of the design process in the materials area --

25

15 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 MEMBER REMPE: So you want them to come 1

up with some way that -- whats allowable to 2

extrapolate, because extrapolation shouldnt be a 3

problem.

4 CHAIRMAN BALLINGER: Dave and I have been 5

going through some of this. There are techniques that 6

you can use, which will also have limitations and 7

conditions and all that kind of stuff, where if you 8

meet those conditions, you can use modeling and 9

simulation. You expand the uncertainty when you do 10 that, but there is --

11 MEMBER REMPE: Sometimes extrapolation 12 isnt so good, though.

13 CHAIRMAN BALLINGER: Extrapolation -- as 14 long as --

15 MEMBER REMPE: Im just curious.

16 CHAIRMAN BALLINGER: Im saying, as long 17 as J. Willard Gibbs is still working for us, 18 extrapolation is okay. There are ways to extrapolate, 19 but there are a lot of cases where you should not.

20 MEMBER REMPE: Yeah. Go ahead. Sorry.

21 I just was curious.

22 MS. AUDRAIN: Well, I think for a lot of 23 these areas, as we start to use the ISG, will identify 24 areas of improvement for another iteration.

25

16 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 CHAIRMAN BALLINGER: Youre trying to 1

plant a seed.

2 MS. AUDRAIN: Yeah.

3 MR. OBERSON: This is Greg Oberson. And 4

just along the lines of modeling and simulation, 5

although its not precise, speaking to that in the 6

context of modeling and simulation for materials 7

performance in the context of this ISG, of course youre 8

aware that we do much in the way of modeling and 9

simulation for neutronics, thermal hydraulics, and so 10 forth.

11 So one of the things -- some of the things 12 that would really be key to that evaluation would be 13 looking at, for instance, the verification and 14 validation of methodologies, and particularly if 15 theres guidance, perhaps that would be needed in that 16 respect as well as the confidence that the models 17 accurately reflect the materials performance data.

18 So point well taken, and thank you for 19 bringing it up.

20 MS. AUDRAIN: It looks like we have a few 21 members of the working group that have their hands 22 raised, too. Dave, do you want to go ahead?

23 MR. RUDLAND: This is Dave Rudland from 24 the Division of New and Renewed Licenses in NRR.

25

17 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 To Rons point, you know, the ASME Code 1

has been spending a lot of effort beginning to 2

investigate modeling and such to help in the 3

qualification of time-dependent high-temperature 4

materials. And the staff is actively following their 5

development, as well as the development of the 6

contractors in their work to do that, to be able to 7

help quickly qualify these high-temperature materials.

8 So were very tied in with that.

9 And, of course, I think as Alex may have 10 said, if something becomes approved through code, the 11 staff of course will give it its full consideration.

12 As for API-579, you know, the differences 13 in degradation behaviors between the information thats 14 in API-579 and that thats in ASME Section 11, of course 15 is different in the fact that, you know, ASME Section 16 11, Section 3, codes are focused on those degradation 17 mechanisms that may be specific to nuclear-grade 18 materials and their applications, where API-579 has 19 a little different -- a little different focus.

20 And this ISG is mainly focusing on those 21 behaviors that are expected at -- you know, for these 22 advanced reactors. And while I think its probably 23 a good idea that we do a cross-check, I think that the 24 stuff thats in the current guidance is covered for 25

18 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 API-579.

1 Thank you.

2 CHAIRMAN BALLINGER: Got it. Thanks. I 3

think the operative word though, Dave, is expected.

4 Im thinking that --

5 MR. RUDLAND: Of course.

6 CHAIRMAN BALLINGER: -- sooner or later 7

when these -- with these new plants we might get what 8

I would call surprised.

9 MR. RUDLAND: Oh. No, we always are. So 10

-- and when -- and we do -- you know, we are as proactive 11 as we can be, looking at the research thats being done, 12 as well as the past operational experience, as well 13 as any testing that is being done or test reactors that 14 will be done. So the staff are staying very aware and 15 on top of the issues.

16 CHAIRMAN BALLINGER: Dont retire, Dave.

17 MS. AUDRAIN: I think we can all second 18 that one.

19 CHAIRMAN BALLINGER: Yeah. No comment on 20 that one. Not saying anything.

21 Thanks.

22 MS. AUDRAIN: All right. An SSCs 23 performance will be demonstrated through a combination 24 of material qualification programs, supplemental 25

19 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 testing, and performance monitoring surveillance 1

programs, which collectively provide assurance that 2

a component will meet the design requirements over its 3

intended life in the applicable operating environment.

4 This ISG identifies that the scope of 5

materials qualification and monitoring program should 6

include safety-related component materials, safety 7

significant component materials, and, as needed, 8

non-safety-related components whose failure could 9

impact critical design functions.

10 The selection of structural materials for 11 the reactor design should consider effects on the 12 material properties and allowable stresses due to 13 interactions with the operating environment.

14 Materials qualification and monitoring programs should 15 include testing conducted or use of historical data 16 collected in an environment simulating the anticipated 17 operating environment for the reactor, including the 18 chemical environment, temperatures, and radiation.

19 Use of any historical data should be 20 directly applicable to the plant design and 21 environment. As seen in their historical data, it 22 should account for uncertainties in the environment, 23 material composition, fabrication

methods, and 24 operating conditions. Testing should be conducted to 25

20 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 determine if material properties and allowable stresses 1

meet applicable codes and standards or other design 2

requirements.

3 Next slide. Performance monitoring and 4

surveillance programs are used in tandem to ensure that 5

a component will continue to meet its design 6

requirements. For components for which there is little 7

data on performance in similar operating environments 8

conditions, performance monitoring and surveillance 9

programs could be an acceptable way to show that the 10 component will maintain its intended function 11 throughout the design life.

12 An example of this could be chemistry, 13 temperature, flow monitoring, or wall thickness 14 measurements. Surveillance programs could include 15 test coupons or SSCs removed and tested during 16 operation, data from which could be used to help predict 17 degradation of components and service.

18 A component with significant design 19 margin, or one that has demonstrated acceptable 20 performance under similar operating environments and 21 conditions, may require less rigorous performance 22 monitoring and surveillance programs.

23 The staff review should include 24 performance monitoring and surveillance programs for 25

21 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 SSCs that are not planning -- planned to undergo 1

periodic inspections or functional testing.

2 MEMBER BROWN: Can I ask a question?

3 MS. AUDRAIN: Mm-hmm.

4 MEMBER BROWN: Im not a materials person 5

like these guys are, but when I was looking at this 6

and what you just said, it gives the impression that 7

you can embark on a new program of materials that are 8

installed in the plant without prior experimental 9

verification that they will actually withstand some 10 of the conditions under which they are going to operate 11 as long as you incorporate coupons and other performance 12 monitoring.

13 Back in the old, old, old, old days, in 14 1950 and so when we started these programs, while we 15 embarked on some of that similar-type stuff, there was 16 some experimental data that was relied on to at least 17 get the program started, but then there were test 18 reactors that did what you would call accelerated 19 experiments to try to characterize, you know, the 20 radiation response and everything else.

21 And this seems to say were not going to 22 be as -- to me it says that were not going to be as 23 complete or as thorough as we did in the past. Is that 24

-- its kind of the way I read some of this.

25

22 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 MS. AUDRAIN: That was not the intention.

1 The intention of this section was to say that we 2

understand that, especially in some areas where theres 3

a long lead time or challenges, especially with the 4

radiation testing, that while that testing is being 5

done, or in addition or supplementing that testing, 6

you could do some other performance monitoring 7

strategies to ensure that the component would say --

8 would satisfy its design criteria.

9 I think the bar for doing that versus having 10 a testing program at all would be very, very high.

11 The intention isnt to say that no testing would ever 12 be required for these components. More that we would 13 be more looking at materials qualification and 14 performance monitoring holistically.

15 MEMBER PETTI: Charlie, my view on this 16 is that there are some things you cannot do until you 17 get to the reactor. And some of these inspections, 18 theyre integral effects tests, if you will. And some 19 of the monitoring will get at things that no matter 20 how good all your testing was outside of the reactor 21 22 MEMBER BROWN: I dont know what --

23 MEMBER PETTI: -- provide assure that --

24 MEMBER BROWN: Im not arguing about the 25

23 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 you know, the in-plant performance stuff. Its just 1

some information that says I can get through six months 2

or maybe a year, but I may not have a complete story, 3

but I can at least have some confidence that when I 4

build something its not -- its going to be okay for 5

more than a very limited period.

6 MEMBER PETTI: Yeah. No, thats --

7 MEMBER BROWN: Thats not the way I read 8

it.

9 MEMBER PETTI: Thats not how I read it.

10 MS. AUDRAIN: That wasnt the intent.

11 MEMBER BROWN: But thats my brain.

12 MS. AUDRAIN: Yeah. That was not the 13 intention of the ISG. It was more to show that for 14 some of the more complicated testing that we wouldnt 15 be preventing reactors from being designed and built, 16 that there are other ways to ensure that the components 17 would meet their design.

18 CHAIRMAN BALLINGER: This is Ron Ballinger 19 again. Not to beat a dead horse, which I will keep 20 beating the dead horse, and that is, to what extent 21 do you think you would consider the substitution 22 temporary, if that, of modeling and simulation for 23 getting at this and satisfying it?

24 MS. AUDRAIN: I think that would be very 25

24 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 design-and materials-specific. It would be hard to 1

give a generic answer to that.

2 CHAIRMAN BALLINGER: Well, but youre not 3

slamming the door.

4 MS. AUDRAIN: No.

5 CHAIRMAN BALLINGER: Okay.

6 MEMBER BROWN: The reason I asked that 7

question is based on that old, old, old experience back 8

in the naval program, there was data taken and you could 9

see nice progress over time of data points going along 10 with an envelope, and all of a sudden it took off going 11 in the wrong direction. And thats one of those 12 surprises.

13 Now, you dont find five-or 10-year stuff, 14 you know, with many programs, but you like to make sure 15 that takeoff is not after three months or six months.

16 Youd like to know there is a period that youve got 17 enough experimental information that says, Yeah.

18 Temperature and radiation combined, whatever, at least 19 gets you through some period wherein, you know, you 20 can recover.

21 It seems that thats not incumbent in the 22 ISG. Thats all. And that was the way I read some 23 of the paragraphs. So thats just -- thats me reading 24 it, and I just wanted to make sure -- I dont think 25

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 you guys intend on going out to lunch. Thats not the 1

point. But its the message sent via an ISG that 2

licensees and other people who want to come forward, 3

you know, see this. Oh, we can do a little bit less 4

than we would have done, because it says they will 5

consider it. Thats all.

6 I will stop right there. It just was my 7

thought process. Thats the way I read it. I didnt 8

have any problem with most of the rest of it.

9 MR. CHERESKIN: Yeah. So this is Alex 10 Chereskin. The only other thing that I would add to, 11 you know, what Meg and others have said is that the 12 ISG is guidance to the staff on what to look for during 13 the review. And so when were having these discussions 14 of where there might be potential tradeoffs or, you 15 know, whatever the mitigation measures you need are, 16 this is guidance to the staff to be able to then look 17 at that when we actually get an application and evaluate 18 it at that time, too.

19 So I dont think were making the 20 conclusive statements that, you know, there is one 21 definitive way to do or not do something.

22 MEMBER BROWN: I understand thats the 23 guidance, same as -- I mean, how you all review it.

24 But notwithstanding that, the people that are going 25

26 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 to be doing things do know what youre going to be 1

reviewing and look for ways so that they can proceed.

2 It may be just nervous when we have lack of 3

understanding. Weve learned a lot, that materials 4

do something strange after a while, as we have found 5

out many, many times.

6 All right. Im done.

7 MS. AUDRAIN: All right. The ISG has two 8

sections on generically applicable materials issues, 9

one for general degradation mechanisms and one for 10 general materials issues. The general degradation 11 mechanisms and material issues are likely to apply 12 across different reactor

designs, operating 13 environments, and materials.

14 The ISG also has three technology-specific 15 appendices. The technology-specific appendices 16 developed were for molten salt reactors, liquid metal 17 reactors, and high-temperature gas-cooled reactors.

18 The topic areas in the ISG were identified by staff 19 through a review of historical documents, NRC technical 20 letter reports, industry gap analysis reports, and 21 literature searches to identify materials topics and 22 degradation mechanisms likely to occur generically and 23 in the specific reactor designs.

24 The mechanisms identified in the ISG 25

27 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 reflect current state of knowledge. However, as 1

additional operating experience and lab testing becomes 2

available, the need to address each identified 3

degradation mechanism or materials issue may change 4

and new ones may be identified.

5 In the ISG, we identify degradation 6

mechanisms that the staff should evaluate if they have 7

been adequately addressed for various reactor 8

environments. The ISG provides information to guide 9

the staffs review for the degradation mechanisms 10 listed on the slide. For each degradation mechanism, 11 the ISG identifies the information to be considered 12 in review, how the degradation mechanism could impact 13 an SSC, and, where applicable, guides the staff to 14 confirm that appropriate mitigation strategies, 15 performance monitoring, and surveillance programs were 16 considered.

17 This information is provided to guide staff 18 review. However, the information required in the 19 application for degradation mechanisms and specific 20 mitigation, performance monitoring, surveillance 21 programs would be design dependent.

22 We also identified the following general 23 materials issues that staff should evaluate if they 24 have been adequately addressed for various reactor 25

28 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 environments. The ISG provides information to guide 1

the staffs review for advanced manufacturing 2

technologies, metallic materials qualification, 3

ceramic insulation, dissimilar metal welds, composite 4

materials, and gasket and seal compatibility.

5 For each materials issue, guidance is 6

provided on the areas to evaluate, the reason for the 7

evaluation, and, where applicable, guides the staff 8

to confirm that appropriate mitigation strategies, 9

performance monitoring, and surveillance programs were 10 considered. These material issues are, again, design 11 dependent and would not be applicable for all designs.

12 The first appendix of the ISG offers 13 details on the design or environment-specific aspects 14 for molten salt reactors. MSR designs fall into two 15 categories: liquid fuel and solid fuel. In a liquid 16 fuel MSR, the fissile material is directly dissolved 17 in the coolant. In a solid fuel MSR, the molten salt 18 coolant has relatively small amounts of fissile 19 material and fission products.

20 They are typically contained within a TRISO 21 fuel particle, which could be in a prismatic graphic 22 compact or a pyrolytic graphic sphere. The design of 23 the MSR will have a large impact on how to review each 24 materials issue identified on the slide.

25

29 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 For example, liquid fuel MSRs will have 1

more material interactions with the fissile material 2

and fission products. The ISG provides information 3

to guide the staffs review for graphite compatibility, 4

various materials considerations, such as degradation, 5

cracking and corrosion, salt composition, and tritium 6

production.

7 There is guidance on specific topics in 8

each header for staff to evaluate. For example, under 9

graphite compatibility, the staff has provided guidance 10 to review graphite salt compatibility, salt 11 infiltration, and abrasion erosion, in addition to 12 other areas. Where applicable, the section guides the 13 staff to confirm that appropriate mitigation 14 strategies, performance monitoring, and surveillance 15 programs were considered.

16 The second appendix to ISG offers details 17 on the design and/or environment-specific aspects for 18 liquid metal reactors, both sodium and lead-cooled.

19 Liquid metal reactors are characterized by the 20 operation at or near ambient pressure using a fast 21 neutron spectrum in which the fuel with metallic 22 cladding is cooled by liquid sodium, lead, or the lead 23 bismuth eutectic.

24 The design and coolants at the liquid metal 25

30 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 reactor will have a large impact on how to review each 1

materials issue. The specific topic areas listed in 2

the ISG for each coolant type are on this slide.

3 However, common areas to review include corrosion, 4

coolant purity and flow rate, and temperature. The 5

staff should evaluate whether applicants have 6

adequately addressed these materials issues as --

7 including, as appropriate, plans to monitor, evaluate, 8

and mitigate degradation.

9 MEMBER REMPE: I had a question. The ISG 10 talks about safety-related and non-safety-related 11 components, systems, and structures. And they talk 12 about instrumentation you need to get this data to do 13 all of this monitoring. But it doesnt distinguish 14 whether more QA is needed for safety-related versus 15 non-safety-related. Have you guys -- what are your 16 thoughts about this, and how would the staff interpret 17 this?

18 MS. AUDRAIN: It wasnt the purpose of this 19 ISG to determine whether a component is or is not safety 20 or non-safety-related.

21 MEMBER REMPE: But if the applicant has 22 a safety-related or a non-safety-related component, 23 do they need to have a better quality of data? And 24 is it clear from the ISG what kind of quality of 25

31 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 instrumentation needs, performance monitoring data, 1

are needed?

2 MS. AUDRAIN: We do have a section on 3

quality assurance in our discussion section of the ISG.

4 I forget the exact language, but the expectation would 5

be that they use an approved UA program for 6

safety-related.

7 MEMBER REMPE: So something that is 8

safety-related needs higher fidelity data. It wasnt 9

obvious to me when I read it, but Ill look at it more 10 carefully.

11 MS. AUDRAIN: The third appendix to the 12 ISG offers details on the design or 13 environmental-specific aspects for high-temperature 14 gas-cooled reactors. HTGRs can use helium or CO2 15 coolant. However, reactors that use CO2 as the coolant 16 are not currently expected to be deployed in the United 17

States, so ISG only addresses degradation 18 considerations that are likely to apply to the helium 19 cooled reactors.

20 The ISG provides information to guide the 21 staffs review for creep rupture strength, emissivity, 22 graphite, graphite dust, helium impurities and 23 carburization, silicon carbide and composites, and 24 lubricant considerations specific to the helium 25

32 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 environment.

1 The ISG identifies the information to be 2

considered in a review for each topic, how the topic 3

could impact the SSC, and, where applicable, this guides 4

the staff to confirm that appropriate mitigation 5

strategies, performance monitoring, and surveillance 6

programs were considered.

7 As Greg mentioned, this ISG went out for 8

a 60-day public comment period this spring. We 9

received comments from eight different entities with 10 a total of 57 comments. As part of the response to 11 this, we made a few notable changes to the ISG.

12 First, we included additional evaluation 13 of carburization and decarburization throughout the 14 ISG for the different reactor designs. We included 15 cladding in the metallic materials qualification 16 section. And we included generic guidance for 17 non-code-qualified materials in the background section 18 rather than having references throughout the ISG.

19 MR. SCHULTZ: Meg, Id like to make a 20 comment. This is Steve Schultz.

21 I would have characterized the public 22 comment period -- not the period, but the public comment 23 process and its results somewhat differently. That 24 is, it was a 60-day comment period, and you did receive 25

33 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 a substantial number of well-intended comments aimed 1

at improving the document or its application.

2 And having reviewed them in some detail, 3

there were a number of comments that the staff -- of 4

those 57, a number of those that the staff did accept 5

and integrate into the report to make fairly valuable 6

changes to the document itself.

7 And then those that you didnt accept you 8

had the opportunity to provide your additional 9

rationale as to why you didnt do that, and in some 10 cases how the comments didnt particularly apply to 11 this document but could be utilized in other ways in 12 the licensing process, and so forth.

13 So I would have -- I would have just 14 characterized it differently in terms of the value of 15 the process. I thought, as I said, the comments were 16 very well intended and quite highly technically 17 oriented to provide information that improve the 18 document.

19 MS. AUDRAIN: Oh, yeah. It was not my 20 intention to dismiss any of the public comments. There 21 were a number of very, very good ones. It was more 22 just to highlight the areas where we had major changes.

23 MR. SCHULTZ: Yeah. I just want to 24 continue to encourage the public process and the comment 25

34 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 process. Thank you.

1 MS. AUDRAIN: In summary, we developed an 2

ISG to develop -- to guide staff on reviewing non-LWR 3

applications using materials allowed under Div 5.

4 Changes were made to address the public comments 5

received for the draft ISG. Our next steps are OGC 6

approval and issuance of this as a final ISG.

7 Thank you.

8 MEMBER REMPE: I had another QA question.

9 There were some documents related to AMT QA 10 requirements that -- and I was wondering, I dont know 11 if weve been involved in the review and whats the 12 status of those documents. It basically said the NRC 13 is in the process of developing both generic and AMT 14 specific guidance for considering the QA of AMT 15 components. Is that something that well see?

16 MS. AUDRAIN: Im going to let either Dave 17 or Rob Tregoning answer that question. Theyre still 18 active participants on the AMT team.

19 MR. RUDLAND: Im happy to make a quick 20 comment on that. So, yeah, the staff of both NRR and 21 Research have been working to develop guidance that 22 is both technology-specific as well as generic over 23 the last couple of years. And through that process, 24 we have developed draft guidelines that pertain to those 25

35 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

-- to those topics that have been sent out for public 1

comment, and such like that.

2 At this particular time, were continuing 3

those efforts. I think the overall goal is to wrap 4

that into some overall guidance. The timeframe of that 5

I think is relatively -- is relatively short term, but 6

I know the staff is still currently working on that.

7 And if ACRS is interested, of course when that time 8

comes wed be happy to bring that to you guys.

9 CHAIRMAN BALLINGER: I think you can 10 assume thats the case.

11 MR. RUDLAND: Ill pass that on to the 12 team.

13 CHAIRMAN BALLINGER: Questions?

14 MEMBER DIMITRIJEVIC: This is Vesna. I 15 have something that I want to support in one of Joys 16 comments just before where she asked about the safety 17 classifications and are the requirements different for 18 the -- you know, the different safety class.

19 And I notice in your guide that you actually 20

-- that was also part of -- I think of some questions 21 which I saw. But, anyway, I notice in your guide that 22 you say that this applies to safety-related, 23 safety-significant, and non-safety components whose 24 failure could impact critical design function.

25

36 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 So certainly you have here three 1

categories, because usually there is just, you know, 2

two -- three different categories. Essentially, you 3

have four categories, because then were going to have 4

non-safety components which dont impact, you know, 5

the critical design function.

6 So this is slightly different than the 7

usual safety classification which we see. So is --

8 do you have an intent for this to be risk-informed?

9 You know, when do you need to start the old degradation 10 mechanisms, and things like that? And why do you have 11 these classifications which are slightly different 12 than, lets say, NEI-0804?

13 MS. AUDRAIN: Well, our intention was to 14 because the likelihood of designs being so different 15 for advanced reactors versus the light water reactors 16 was to make sure that any component that would be relied 17 upon for safety, whether it was classified as non-safety 18 or safety, would still be reviewed by staff to ensure 19 that the component would meet its design criteria.

20 Does that answer your question?

21 MEMBER DIMITRIJEVIC: But you understand 22 my question. You have a little -- you have added this 23 category, non-safety, whose failure could impact 24 control design function. And that will mean 25

37 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 non-safety, non-risk-significant, but impacts critical 1

design function.

2 So, you know, I mean, I dont know, but 3

I will bet non-safety-significant. But, anyway, this 4

is some additional category you are adding, and 5

basically do you want to cover everything? I mean, 6

or -- I mean, as you said, you just want to make sure 7

that they address everything which is done.

8 But I just want to say that your 9

classification is not really consistent with 10 classifications we see for the non-light-water reactors 11 in the, you know, classification process.

12 So this is just my comment. Just, you 13 know, take it with a grain. On one of the comments, 14 which you get from the public, you said that you --

15 you know, you had to three categories, and you dont 16 intend to change this.

17 CHAIRMAN BALLINGER: Other comments from 18 the members or consultants? Okay. Were rapidly 19 approaching a worlds record, a presentation to the 20 ACRS which is less than an hour long.

21 Yeah, thats right. By materials people.

22 (Laughter.)

23 CHAIRMAN BALLINGER: Were encroaching on 24 thermal hydraulics territory.

25

38 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 So we need to go out for public comments.

1 If there are members of the public that would like 2

to make a comment, please state your name and your 3

organization, and please unmute yourself and make your 4

comment.

5 Hearing none, this is a very short meeting, 6

but the purpose of the meeting was to make sure that 7

the members are all familiar with this issue, because 8

were going to be constantly dealing with new materials 9

as submittals come through, and to have this available 10 and this knowledge will serve us well I think.

11 So Ill --

12 MEMBER HALNON: Ron, what are they using 13 now, like, for instance, the reactor we heard this 14 morning and the reactor well hear this fall?

15 CHAIRMAN BALLINGER: Im guessing that 16 theyre using this. I can tell you that the Kairos 17 people are.

18 MEMBER HALNON: Okay.

19 CHAIRMAN BALLINGER: For sure. I mean, 20 if you read their --

21 MS.

AUDRAIN:

Just a

point of 22 clarification. The Kairos review was done for the 23 topical reports prior to this being issued publicly.

24 CHAIRMAN BALLINGER: Okay. I get your 25

39 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 point. But if you read it, theres a certain 1

familiarity with the topics and things in there, and 2

the order.

3 MR. CHERESKIN: Yeah. I understand that.

4 There are a lot of common staff working on both the 5

Kairos project and this project as well. And so I --

6 you know, I think we can --

7 CHAIRMAN BALLINGER: I mean, thats a 8

testimony to the efficacy of what youre doing. I mean, 9

people are starting to use them.

10 MEMBER HANLON: All that informed what 11 we see here, anyway. I mean, because there is a lot 12 of material here. You just didnt make this up over 13 the last three months. I mean, this is a lot of stuff.

14 MS. AUDRAIN: No. Weve been working on 15 this ISG for a couple of years. We just want to make 16 very clear that Kairos did not get a preview of this 17 document before anybody else, but it was --

18 MR. CHERESKIN: Very smart.

19 MS. AUDRAIN: -- similarities are because 20 the same staff worked on both projects.

21 MEMBER HALNON: So would it be considered 22 a backfit to impose this guidance on, like, Kairos and 23 some of the reactors that have already been somewhat 24 designed but maybe not submitted?

25

40 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 MS. AUDRAIN: This is staff guidance.

1 Its not guidance for applicants.

2 MEMBER HALNON: Yeah. But we all know 3

what staff guidance means.

4 MS. AUDRAIN: I think its fair to say that 5

because the same people who developed this guidance 6

have been working on the advanced reactor applications 7

8 MEMBER HALNON: Thats a very iterative 9

process. I mean -- thanks.

10 MR. CHERESKIN: One other thing I would 11 note, that I was just talking about, you know, the timing 12 of this and what the staff -- you know, kind of our 13 knowledge base, youre right, this wasnt developed, 14 obviously, in a matter of days or months.

15 But, I mean, even if you look at some of 16 the references going back, we cite technical letter 17 reports from the NRC Office of Research that were, you 18 know, from 2020, 2021, and so this is a couple of years 19 I think kind of in the making, with us crediting that.

20 And a lot of the staff that worked on these things 21 are familiar with the work our colleagues in Research 22 have been doing as well.

23 So, yeah, and it kind of also has, like, 24 a common source for, you know, the reviews and us putting 25

41 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 together this ISG.

1 CHAIRMAN BALLINGER: I mean, its very 2

timely. Im surprised it took this long.

3 Okay. If there arent any other comments, 4

and I could ramble along for another 10 minutes and 5

make it an hour, but I wont do that. So -- were good 6

at that.

7 Anyway, thank you very much for spending 8

the -- I did. What, do you mean to do it again?

9 Okay. Thank you very much again, and we 10 are adjourned.

11 (Whereupon, the above-entitled matter went 12 off the record at 1:50 p.m.)

13 14 15 16 17 18 19 20 21 22 23 24 25

Interim Staff Guidance on Materials Compatibility in Advanced Reactor Environments Meg Audrain, Alex Chereskin and Matt Gordon Office of Nuclear Reactor Regulations August 23, 2023 ACRS Subcommittee Meeting

Agenda

• Purpose and Applicability of Interim Staff Guidance (ISG)

• Regulatory Framework

• Qualification and Performance Monitoring

• Technical Content

• Public Comment Resolution

• Conclusions and Questions 2

Purpose for Development of ISG

• Anticipate non-light water reactor (LWR) applicant use of ASME Section III, Division 5 (Div 5), High Temperature Reactors

• Account for environmental effects in assessment of service life for structures, systems and components (SSCs)

• Address lack of existing staff guidance on the review of materials qualification, performance monitoring methods, and surveillance for non-LWRs

• Ensure consistency and clarity for application reviews, including identification of:

- Information related to materials qualification, and

- Appropriate monitoring and surveillance programs.

3

Non-LWR Environment

• Corrosion and other materials degradation phenomena may significantly differ from LWR environments

• Lack of test data and operational experience gives rise to knowledge gaps for the materials-environmental interactions in non-LWRs

• Use of appropriate mitigation strategies, performance monitoring, and surveillance programs will be emphasized by staff to ensure SSCs continue to satisfy the design criteria 4

ISG Applicability Staff reviews of non-LWR power, research or test reactors that propose the use of materials allowed under Div 5

• Part 50 - construction permit and operating license

• Part 52 - design certification, combined license, standard design approval, or manufacturing license 5

Current Regulatory Framework

• Staff evaluate performance of SSCs with reference to the facility principal design criteria (PDCs) required by 10 CFR 50.34(a)(3)(i), 10 CFR 52.47(a)(3)(i) and 10 CFR 52.79a(4)(i)*

• ISG addresses staff review of materials qualification, performance monitoring, and related issues to ensure conformance with PDCs.

6

• See also Regulatory Guide (RG) 1.232, Guidance for Developing Principal Design Criteria for Non-Light Water Reactors

Qualification and Performance Monitoring -

Terminology

• Materials qualification

- Testing conducted in an environment simulating the anticipated operating environment for the reactor, including chemical environment, temperatures, and irradiation

• Performance monitoring

- Inspections or examinations to confirm adequate performance and to identify unacceptable degradation such as chemistry temperature or flow monitoring, or wall thickness measurements

- May also include aging management programs or post-service evaluations

• Surveillance programs

- Examination of test coupons and components removed from the reactor over the licensed operating period 7

Qualification and Performance Monitoring

Purpose:

Demonstrate that a component will meet the design requirements over its intended design life in the applicable environment

• Scope: Safety-related and safety-significant component materials, and as needed, non-safety related component materials whose failure could impact critical design functions

• Testing: Determine if materials properties and allowable stresses meet applicable codes and standards or other design requirements 8

Performance Monitoring and Surveillance

• Expected scope of programs will depend, in part, on availability of testing data

• Robust monitoring and surveillance programs may provide appropriate confidence when:

-There is a limited set of testing data

-Periodic inspections and/or functional testing of SSCs is not planned 9

Technical Content of ISG

• Degradation issues

- Generically applicable

- Technology specific 10

• Technology-specific appendices

- Molten salt reactors

- Liquid metal reactors

- High temperature gas reactors Represents current state of knowledge - subject to change based on evaluation of further test data and operating experience

Generally Applicable Degradation Mechanisms

• Carburization

• Corrosion

• Environmental effects on creep and creep fatigue

• Environmentally assisted cracking

• Flow induced degradation (abrasion, erosion, cavitation) 11

• Flow induced vibration

• Irradiation effects

• Stress relaxation cracking

• Thermal aging, thermal emissivity, thermal fatigue and transients

• Coolant Flow, wear, and fretting

Other Generally Applicable Materials Issues

• Advanced manufacturing technologies

• Metallic materials qualification considerations

• Ceramic insulation

• Dissimilar metal welds

• SiC, C/C, and SiC/SiC composites

• Gaskets and seal chemical compatibility 12

Molten Salt Reactor Appendix

• Graphite compatibility

• Materials considerations (degradation, cracking, corrosion)

• Salt composition

• Tritium production 13

Liquid Metal Reactor Appendix Sodium-cooled fast reactors

• Caustic stress-corrosion cracking

• Exothermic reactivity with water

• Sodium impurity effects on corrosion

• Liquid metal embrittlement

• Carburization and decarburization Lead-cooled fast reactors

• High temperature corrosion

• Effect of flow velocity

• Liquid metal embrittlement

• Nonmetallic materials

• Oxygen control 14

High Temperature Gas Cooled Reactor Appendix

• Creep-rupture strength

• Emissivity

• Graphite

• Graphite dust

• Helium impurities and carburization

• SiC and composites

• Lubricants 15

Public Comment Period

• 60-day public comment period: spring 2023

• Received comments from 8 entities, total of 57 comments

• Only a few notable changes:

- Additional evaluation of carburization/decarburization

- Addition of cladding in Metallic Materials Qualification

- Addition of generic guidance for non-code qualified materials in background section rather than references throughout ISG 16

Summary

• NRC staff developed an ISG to guide staff on reviewing non-LWR applications using materials allowed under Div 5

• Limited changes were made to address public comments received for the draft ISG

• Next steps - OGC approval and issuance as final ISG 17

Questions?

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