ML22286A058
| ML22286A058 | |
| Person / Time | |
|---|---|
| Issue date: | 10/04/2022 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Wang, W., ACRS | |
| References | |
| NRC-2115 | |
| Download: ML22286A058 (38) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactive Safeguards Materials, Metallurgy, and Reactor Fuels Open Session Docket Number:
(n/a)
Location:
teleconference Date:
Tuesday, October 4, 2022 Work Order No.:
NRC-2115 Pages 1-22 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1716 14th Street, N.W.
Washington, D.C. 20009 (202) 234-4433
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com 1
1 2
3 DISCLAIMER 4
5 6
UNITED STATES NUCLEAR REGULATORY 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 MATERIAL, METALLURGY, AND REACTOR FUEL SUBCOMMITTEE 7
+ + + + +
8 OPEN SESSION 9
+ + + + +
10 TUESDAY 11 OCTOBER 4, 2022 12
+ + + + +
13 The Subcommittee met via Video-14 Teleconference, at 1:00 p.m. EDT, David Petti, 15 Chairman, presiding.
16 17 COMMITTEE MEMBERS:
18 DAVID PETTI, Chair 19 VICKI BIER, Member 20 GREGORY HALNON, Member 21 WALTER KIRCHNER, Member 22 JOSE MARCH-LEUBA, Member 23 JOY REMPE, Member 24 MATTHEW SUNSERI, 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 ACRS CONSULTANT:
1 STEPHEN SCHULTZ 2
3 DESIGNATED FEDERAL OFFICIAL:
4 WEIDONG WANG 5
6 ALSO PRESENT:
7 ANDREW ATWOOD, Westinghouse 8
KEVIN BARBER, Westinghouse 9
ZACH HARPER, Westinghouse 10 SCOTT KREPEL, NRR 11 YUN LONG, Westinghouse 12 JOSEPH MESSINA, NRR 13 GUIRONG PAN, Westinghouse 14 MATHEW PANICKER, NRR 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
1:00 p.m.
2 CHAIR PETTI: Okay, this meeting will now 3
come to order. This is a meeting of the Materials, 4
Metallurgy, and Reactor Fuel Subcommittee of the 5
Advisory Committee on Reactive Safeguards. I'm Dave 6
Petti, chairman of today's subcommittee meeting, 7
pinch-hitting for Member Ballinger who can't be with 8
us. ACRS members in attendance are Jose March-Leuba, 9
Matt Sunseri, Walt Kirchner, Vicki Bier, Greg Halnon, 10 and Vesna, are you out there? No.
11 Consultants Dennis Bley and Steve Schultz, 12 are you out there? Thanks, Dave. Okay. Weidong Wang 13 of the ACRS staff is the Designated Federal Official 14 for this meeting.
15 During today's meeting, the subcommittee 16 will review the staff safety evaluation on WCAP 18546-17 P entitled Westinghouse AXIOM Cladding for Use in 18 Pressurized Water Reactor Fuel, Enclosure 2, Revision 19 0.
20 The subcommittee will hear presentations 21 by and hold discussions with the NRC staff, 22 Westinghouse Electric Company representatives, and 23 other interested persons regarding this matter.
24 The parts of the presentation by 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
4 applicant and the NRC staff may be closed in order to 1
discussion information that is proprietary to the 2
licensee and its contractors pursuant to 5 USC 3
552(b)(c)(iv).
4 Attendance at the meeting that deal with 5
such information will be limited to the NRC staff and 6
its consultants, Westinghouse, and those individuals 7
and organizations who have entered into an appropriate 8
confidentiality agreement with them. Consequently, we 9
need to confirm that we have only eligible observers 10 and participants in the closed part of the meeting.
11 The rules for participation in all ACRS 12 meetings including today and so announced in the 13 Federal Register on June 13th, 2019, the ACRS section 14 of the US NRC public website provides our charter, 15 bylaws, agendas, letter reports, and full transcript 16 of all full and subcommittee meetings, including 17 slides presented there.
18 The meeting notice and agenda for this 19 meeting were posted there as well.
20 We have received no written statements or 21 requests to make oral statements from the public.
22 The subcommittee will gather information, 23 analyze relevant issues and facts, and formulate 24 proposed positions and actions as appropriate 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
5 deliberation by the full committee.
1 The rules for participation in today's 2
meeting have been announced as part of a notice of 3
this meeting previously published in the Federal 4
Register.
5 A transcript of the meeting is being kept 6
and will be made available, as stated, in the Federal 7
Register notice.
8 Due to the COVID pandemic, today's meeting 9
is being held both at NRC headquarters and over 10 Microsoft Teams for ACRS, NRC staff, and licensee 11 attendees. There is also a telephone bridge line 12 allowing participation of the public over the phone.
13 When addressing the subcommittee, the 14 participants should first identify themselves and 15 speak with sufficient clarity and volume so they may 16 be readily heard. When not speaking, we request that 17 participants mute their computer microphone or phone 18 by pressing star-6.
19 With that, we'll now proceed with the 20 meeting and I'd like to start by calling upon NRR 21 management to make an opening statement.
22 MR. KREPEL: (through an interpreter) 23 Hello, everyone. This is Scott Krepel. I'm the 24 Branch Chief for the Nuclear Methods and Fuel Analysis 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 Branch and it is my staff, Joey Messina and Matthew 1
Panicker who have both performed the review and will 2
be giving that presentation today.
3 I understand that Westinghouse has some 4
good responses to all of the questions that the staff 5
has had, as well as has conducted fellow reviews. I 6
look forward to hearing more about it since I just 7
became their branch chief about two months ago. So 8
I've not heard all of the details yet about this 9
particular review.
10 Thank you so much.
11 CHAIR PETTI: Thank you, Scott. So I call 12 on Westinghouse to begin, please.
13 MR. ATWOOD: Thank you, Mr. Chairman. My 14 name is Andrew Atwood. I'm the manager of the 15 Materials and Fuel Rod Design Group for Westinghouse 16 and I'm going to be providing the open session 17 overview of our AXIOM topical which is WCAP 18546 18 which is seeking use for AXIOM in fresh water reactor 19 applications.
20 CHAIR PETTI: Can you pull the microphone 21 a little closer to you? I think people online here 22 will hear better.
23 MEMBER MARCH-LEUBA: Let me interrupt you.
24 If we can blow up the slides, too, it would be easier 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 to see in the presentation mode or --
1 MR. ATWOOD: So AXIOM fuel cladding is 2
Westinghouse's next evolution of zirconium based PWR 3
fuel materials. AXIOM builds on our successful 4
history with ZIRLO niobium-10 cladding where we've 5
further refined that with AXIOM by reducing the tin 6
content and also adding copper and vanadium along with 7
a refined final heat treatment to deliver a number of 8
material performance improvements, specifically 9
improved corrosion resistance with a reduced hydrogen 10 pickup fraction as a result of that; reduction in 11 cladding creep rates in normal operation; excellent 12 dimensional stability, and we have proven operating 13 experience in a number of test campaigns in various 14 test reactors and power reactors around the world.
15 So our intent is to use AXIOM in region 16 applications for all of our pressurized water reactor 17 customers.
AXIOM is fully compatible with 18 conventional and ADOPT doped pellet CO2 fuel.
19 WCAP 18546 was submitted in March of last 20 year, requesting approval for the use of AXIOM in all 21 currently approved PWR fuel designs. Our nickel 22 burnup limit is 62 gigawatt days per MTU and the 23 topical includes new fuel performance models for AXIOM 24 including strength, fuel rod growth, cladding creep 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 behavior, and corrosion.
1 These models and benefits enable improved 2
performance by providing lower corrosion and hydro 3
pickup, at higher duties and higher burnups while 4
maintaining improved dimensional stability. And the 5
properties and performance models for AXIOM cladding 6
has been incorporated into existing NRC-approved 7
analytical methods for use in plant-specific safety 8
analyses.
9 MEMBER MARCH-LEUBA: Let me interrupt you 10 for a moment. I've read ahead on the proprietary 11 section, you are going to discuss more about the 62 12 gigawatt --
13 (Simultaneous speaking.)
14 MEMBER MARCH-LEUBA: Is there something 15 you can say to the public about why you chose 62 and 16 what are your plans to increase it?
17 MR. ATWOOD: 62 is our current burnup 18 limit for our existing fuel designs, so we thought 19 first to maintain that with AXIOM. We have operated 20 AXIOM to burnups in excess of 70,000 gigawatts --
21 megawatt days per MTU and so we are going to be 22 seeking an increase in the burnup limit in the future.
23 It will be a separate submittal.
24 MEMBER MARCH-LEUBA: And there will be 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
9 future topical report or just a license amendment?
1 MR. ATWOOD: It's going to be its own 2
submission. It actually ties in a number of different 3
things, so I want to make sure my licensing colleagues 4
have the opportunity to weigh in on that.
5 MR.
HARPER:
- Yes, Zach
- Harper, 6
Westinghouse. So it will be a future submittal, 7
future topical to the extent of burnup.
8 MEMBER MARCH-LEUBA: Thank you.
9 MR. ATWOOD: Thank you for the question.
10 So the status of the topical to date, the NRC has 11 conducted a technical audit in October of last year, 12 October and November. A supplement has been submitted 13 to provide the necessary data for using AXIOM with our 14 ADOPT fuel. We have provided responses to several 15 requests for additional information in areas including 16 the material properties and performance models, the 17 fuel rod design models that we used with AXIOM, and 18 the criterion methods that we used for our LOCA 19 analysis as well as reactivity insertion accidents, 20 seismic, and other types of accidents.
21 The draft safety evaluation report for the 22 WCAP was received beginning of September of this year, 23 and we thank the NRC for the opportunity to review 24 that draft. We have provided some comments and we're 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 working on resolution of those now.
1 In summary, AXIOM is in the process of 2
being licensed and implemented for PWR fuel. We have 3
completed the AXIOM material development program based 4
on our experience gained with the development and 5
operation of both serial and optimized ZIRLO 6
claddings. The topical is presently under NRC review 7
and we do anticipate the final SER this year, if all 8
goes according to plan. And we do anticipate on 9
including a supplemental on AXIOM for higher burnups 10 in the future.
11 MEMBER MARCH-LEUBA: Something that my 12 interest on this slide is "full region." You mean all 13 the domains where you ask -- there is no limitations 14 on the domain, you ask for performance or --
15 MR. ATWOOD: Well, I guess region in this 16 sense would be complete reloads of fuel, but we're 17 seeking to operate it according to our methods that 18 are already licensed --
19 MEMBER MARCH-LEUBA: You can load a full 20 100 percent --
21 MR. ATWOOD: Yes.
22 MEMBER HALNON: This is Greg. The 23 comments that are turned back to the NRC, any show 24 stoppers in those or are you guys okay with what'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
11 included in the SE?
1 MR. HARPER: Again, this is Zach Harper, 2
Westinghouse Licensing. Yes, no show stoppers. It is 3
largely editorial, changing proprietary brackets, 4
things like that. Limits, conditions, all that is 5
fine. I'm just trying to make sure that the final SCR 6
that goes and gets attached to the topic (audio 7
interference). Nothing significant.
8 MR. ATWOOD: Steve, go ahead.
9 MR. SCHULTZ: This is Steve Schultz. A 10 couple of questions. The first was if you -- again, 11 for the benefit of the public that are listening since 12 this is the open session, you mention on your first 13 slide that you're achieving enhanced dimensional 14 stability and that there's an opportunity to provide 15 better performance with regard to fuel rod growth. At 16 least that's my interpretation of it.
17 Can you provide perhaps a more detailed 18 qualitative description of what you are achieving with 19 regard to the dimensional stability compared to the 20 current fuel design? That's one question. I'll ask 21 my other one here, too.
22 Can you provide a little more information 23 about the experience base that you do have with this 24 fuel as compared to what you have had in place 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
12 previous design changes for the cladding that you have 1
licensed previously?
2 MR. ATWOOD: Yes, first as far as growth 3
is concerned, we have irradiated AXIOM in both 4
prototypic fuel rod configurations as well as unfueled 5
samples to burnups that exceed our 62 gigawatt day 6
limit that we currently have. And we see good linear 7
behavior as a function of accumulated burnup. I think 8
even in equivalent burnups up to more 80 gigawatt 9
days.
10 MS. PAN: This is Guirong Pan. I'm the 11 technical lead for AXIOM developmental program. So 12 I'll answer the question about the growth. We have 13 some publications, including AXIOM growth compared 14 with (indiscernible due to accent) ZIRLO and the ZIRLO 15 cladding. You can see that the AXIOM growth is 16 relatively flat. There's no accelerated growth, even 17 at high burnup, like above 70 gigawatt days per metric 18 tons uranium. So one advantage for AXIOM compared to 19 current product is at higher burnup the growth is 20 lower.
21 MEMBER HALNON: This is Greg. Does that 22 include fuel assembly warping or twisting of any kind 23 that would make refueling more difficult?
24 MR. ATWOOD: We've had some experience 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 with lead test assemblies that are quote fully AXIOM 1
fuel clad. Those are at burnups that still compliant 2
with the current license limits. We've certainly not 3
seen any issues with dimensional stability in the 4
fuel, and we anticipate that remaining true for AXIOM 5
as well, given that it is -- it's not prone to 6
breakaway growth. You're not going to have a lot of 7
interactions with the fuel rods and the fuel assembly.
8 A lot of our very high burnup data is on 9
lead test rod applications for --
10 (Simultaneous speaking.)
11 MR. ATWOOD: But all indication is that 12 it's at least better than what we have.
13 MR. SCHULTZ: That's good news. Thank 14 you. This is Steve Schultz.
15 MR. HARPER: Steve, you may have to 16 restate your second question.
17 MR. ATWOOD: Oh, I believe the second 18 question was what -- can we elaborate on our 19 experience phase of test radiations. I have to be 20 pretty careful of what's proprietary and the partners 21 we've worked with.
22 We have irradiated both samples of AXIOM 23 and some prototypic fuel rod forms in both test 24 reactors as well as a number of power reactors 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
14 U.S. and in Europe, in a variety of different 1
conditions, to include both varying chemistry as well 2
as operating cycle rates.
3 Dr. Pan, I don't know if you happen to 4
have the rough numbers off the top of your head, but 5
I believe in the topical there's a table that outlines 6
the different menus where we've gained our test 7
radiation experience.
8 CHAIR PETTI: So, just to clarify, there's 9
all these data plots I remember in the report and 10 comparisons to your previous to cladding, ZIRLO and 11 Optimized ZIRLO. But I guess the question I'd be most 12 interested because I assume that some of that is 13 actual licensed fuel that's in reactors. If you ask 14 yourself when you came in to the NRC to get ZIRLO 15 approved and optimized ZIRLO approved, you've got a 16 certain amount of data. You have more data for AXIOM 17 or about the same amount as you had for those products 18 when you came?
19 MR. ATWOOD: I would say in terms of 20 AXIOM, we have more data than what we had brought for 21 optimized ZIRLO. I'd have to go back and actually 22 quantify what the differences are, but AXIOM is a new 23 alloy because of the additions of the copper and the 24 vanadium, so we did make a deliberate review of 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
15 the different types of data that we would have to 1
bring knowing that we couldn't just rely on it being 2
an extension of the existing ZIRLO family.
3 CHAIR PETTI: Thanks. That's helps.
4 Other questions, members? No? Okay. Thank you very 5
much.
6 MR. PANICKER: This is Matthew Panicker.
7 I am in the Nuclear Methods and Fuel Analysis Group.
8 Me and Joseph Messina did the overall review of the 9
topical report that we are presenting in the open 10 session. A few slides on the review results of the 11 topical report, WCAP 18546PNP, Materials, AXIOM 12 cladding for use in the pressurized water reactor 13 fuel.
14 Next slide, please. This slide has --
15 Westinghouse submitted the AXIOM topical report on 16 March 2021 and we reviewed, and from that, the topical 17 (indiscernible due to accent) micro-structure of 18 AXIOM, which is an alloy of zirconium alloy, thermal 19 properties, mechanical properties that just 20 (indiscernible due to accent), et cetera. Radiation 21 programs and operating experience (indiscernible due 22 to accent) and the results were from the 23 (indiscernible due to accent) reactors where AXIOM was 24 exposed to. AXIOM cladding behavior, corrosion 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 (indiscernible due to accent), AXIOM growth, cladding 1
irradiation creep, (indiscernible due to accent) 2 rejection accident in accordance with the 3
(indiscernible due to accent) 1.236.
4 Irradiated mechanical properties are just 5
AXIOM and (indiscernible due to accent) tensile 6
strength test. Licensing criteria for fuel rod 7
design. All of the safety analysis is done with the 8
full (indiscernible due to accent) of AXIOM fuel.
9 Loss of coolant accident, non-LOCA, containment 10 integrity (indiscernible due to accent). And the 11 seismic irradiation for both beginning of life and end 12 of life, combined with LOCA evaluation, (indiscernible 13 due to accent) thermal-hydraulic
- design, and 14 (indiscernible due to accent) analysis. These are the 15 topics which we reviewed.
16 Next, please. (Indiscernible due to 17 accent) acceptance review, accepted the topical 18 report, sometime early 2021. A regulatory audit was 19 conducted on all the available documents related to 20 performance, related to testing, LTAs, et cetera, of 21 AXIOM fuel in European and American reactors. And 22 that was done through the electronic (indiscernible 23 due to accent) group, which lasted for several weeks.
24 During the audit (indiscernible due to accent) interim 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 responses were received. At the end of the audit and 1
also requests for additional information 2
(indiscernible due to accent). RIA responses were 3
received in February 2022. And before the end of the 4
review, in December 2021, Westinghouse submitted a 5
supplement to the WCAP 18546 to extend the 6
applicability to adopt fuel rod because the original 7
AXIOM topical report was meant for (indiscernible due 8
to accent) without any additives. So (indiscernible 9
due to accent) with an additive.
10 Next, please. This slide shows some of 11 the basic review based on these regulatory evaluations 12 EDC 10 which designs the (indiscernible due to 13 accent). Design limits (indiscernible due to accent) 14 pressure (indiscernible due to accent) LOCA analysis.
15 The (indiscernible due to accent) A11 (indiscernible 16 due to accent) that is regarding the acceptance 17 criteria of the loss-of-coolant accident. And also 18 Appendix K, evaluation for LOCA, (indiscernible due to 19 accent) and these are the main regulatory aspects 20 based on which we did the review.
21 Next, please. These are some of the --
22 these are the (indiscernible due to accent) 546 23 proprietary information on all these details. And 24 also the details are not there in the topical report, 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 we asked for expanding them to RAA (phonetic) and 1
their responses.
2 Micro-structure, micro-hardness, phased 3
transition (indiscernible due to accent) ratio, 4
specifically thermal (indiscernible due to accent),
5 melting temperature (indiscernible due to accent) 6 thermal expansion, these are the thermal properties.
7 The elastic modeling (indiscernible due to accent) 8 high temperature (indiscernible due to accent) 9 reaction (indiscernible due to accent) orientation, 10 radiation programs and (indiscernible due to accent) 11 experience. So those are the mechanical and 12 characterization of the (indiscernible due to accent) 13 fuel.
14 Next, please. These are some of the 15 characterizations of the AXIOM fuel or the licensing 16 criteria. (indiscernible due to accent) accident 17 limits according to RG 1.236. Fuel performance and 18 licensing aspects (indiscernible due to accent), fuel 19 loading(indiscernible due to accent) pressure, RAP, 20 (indiscernible due to accent) clad wear, cladding 21 fatigue, cladding oxidation, cladding (indiscernible 22 due to accent),
cladding
- fatigue, cladding 23 freestanding, (indiscernible due to accent), cladding 24 (indiscernible due to accent) PCA, (indiscernible due 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 to accent) LOCA and non-LOCA, rad incidents, and 1
(indiscernible due to accent) analysis. These are the 2
various aspects with respect to the licensing criteria 3
of the (indiscernible due to accent).
4 Next, please. (Indiscernible due to 5
accent)
NRC staff has determined that the 6
(indiscernible due to accent) approach (indiscernible 7
due to accent). The staff reviewed AXIOM fuel load 8
(indiscernible due to accent) interior and safety 9
analysis for both LOCA and non-LOCA methodologies.
10 (Indiscernible due to accent) regarding the 11 (indiscernible due to accent) of this TR will be 12 discussed during the closed session. That's all we 13 have for the open session.
14 CHAIR PETTI: Thank you. Questions, 15 staff, members?
16 MEMBER KIRCHNER: Matthew, this is Walt 17 Kirchner. When you get -- this is more a little bit 18 of process rather than details of AXIOM. When you get 19 an application like this, usually a TR for new fuel 20 form, do you typically run confirmatory calculations 21 with your -- well, it used to be FRAPCON. I think 22 it's called FRAS now. Do you put in some of the key 23 properties or the delta change in properties for Zirc 24 cladding families and then run any of your in-house 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 codes with the assistance of research to kind of 1
benchmark the applicant's submittal?
2 MR. PANICKER: Generally speaking, most of 3
the fuel performance and fuel or fuels like AXIOM or 4
(indiscernible due to accent) we do confirmatory 5
calculations. But in this case, AXIOM, we used the 6
first code to confirm some of the results presented to 7
us by Westinghouse and thus, most likely will be a 8
person like my colleague, Joseph Messina.
9 MR. MESSINA: Yes, Joseph Messina from the 10 staff. So we contracted out with PNNL to update to a 11 proprietary version of FRAS and with that we did some 12 confirmatory calculations that may be discussed more 13 in the proprietary session.
14 MEMBER KIRCHNER: Right. I just wanted to 15 get this on the record. But it's not just a -- what 16 shall I call it, a review of the submittal, but 17 actually do some independent confirmatory work to --
18 can you suggest in a public forum what the key areas 19 you looked at?
20 MR. MESSINA: Yes. So we looked -- we ran 21 similar cases with optimized ZIRLO and AXIOM and 22 ensured that (a) that AXIOM behaved similar to what 23 was presented in the topical report and that it 24 behaved not largely different, that the difference 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 wasn't detrimental compared to optimized ZIRLO. It 1
behaved similar or better and in the cases that it 2
would behave maybe slightly worse, but not to any 3
significant --
4 MEMBER KIRCHNER: I think key ones that I 5
would look at would be honestly the activity insertion 6
accidents and Reg. Guide 1.256 is probably one of the 7
more important ones simply because that's one of the 8
most stressful events scenarios for a cladding fuel 9
system to be subjected to. So okay, I just wanted 10 something on the public record that it was more than 11 a literature review. Thank you.
12 CHAIR PETTI: Steve, go ahead.
13 MR. SCHULTZ: Just to go one step further 14 in terms of the transient analyses and accident 15 analyses that were performed, did you do side by side 16 or any evaluations associated with the LOCA analysis?
17 MR. PANICKER: No, we didn't do that. We 18 reviewed the applicability of the (indiscernible due 19 to accent) LOCA and the (indiscernible due to accent) 20 LOCA at Westinghouse. (indiscernible due to accent) 21 and then we came to some conclusions.
22 MR. SCHULTZ: So you looked at the -- you 23 had a long list of fuel mechanical and thermal 24 properties changes that were done and so you evaluated 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 those by examining the Westinghouse analyses 1
associated with those accidents?
2 MR. PANICKER: Right.
3 MR. SCHULTZ: I understand.
4 MR. PANICKER: Yes.
5 MR. SCHULTZ: Thank you.
6 CHAIR PETTI: Okay, so let's open for 7
public comments before actually going to a closed 8
session. Does any member of the public that has a 9
comment, please state your name for the record and 10 your comment?
11 Hearing none, then this ends the open 12 session and we will now move to closed session. Thank 13 you.
14 (Whereupon, the above-entitled matter went 15 off the record at 1:34 p.m.)
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
Westinghouse Non-Proprietary Class 3 LTR-NRC-22-40 Page 1 of 7 AXIOM, ZIRLO, Optimized ZIRLOTM, ADOPTTM are trademarks of Westinghouse Electric Company LLC, its affiliates, and/or its subsidiaries through the United States of America and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners.
Westinghouse Electric Company 1000 Westinghouse Drive Cranberry Township, PA 16066
© 2022 Westinghouse Electric Company LLC All Rights Reserved Westinghouse Open Session Slide Package for the ACRS Subcommittee Meeting on WCAP-18546-P/NP (Non-Proprietary)
September 2022
1 Westinghouse Non-Proprietary Class 3
© 2022 Westinghouse Electric Company LLC. All Rights Reserved.
AXIOM, ZIRLO, Optimized ZIRLO', and ADOPT' are trademarks or registered trademarks of Westinghouse Electric Company LLC, its affiliates and/or its subsidiaries in the United States of America and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners.
LTR-NRC-22-40, Enclosure 2 Page 2 of 7
Westinghouse Non-Proprietary Class 3
© 2022 Westinghouse Electric Company LLC. All Rights Reserved.
2 Westinghouse AXIOM Cladding for Use in Pressurized Water Reactor Fuel, WCAP-18546-P/NP Andrew Atwood, Manager, Materials and Fuel Rod Design October 4, 2022 LTR-NRC-22-40, Enclosure 2 Page 3 of 7
3 Westinghouse Non-Proprietary Class 3
© 2022 Westinghouse Electric Company LLC. All Rights Reserved.
AXIOM Fuel Cladding
- AXIOM Cladding is Westinghouses next evolution of zirconium-based PWR fuel cladding materials
- AXIOM builds on the Zr-Nb-Sn alloy system from the ZIRLO family of alloys via a further reduction in Sn and the addition of Cu and V along with an alloy-specific final heat treatment providing:
- Improved corrosion resistance and reduced hydrogen pickup
- Reduced cladding creep rates
- Excellent dimensional stability
- Proven operating experience
- Intended for use in region applications of fuel for all PWR customers
- Compatible with conventional and ADOPT'doped pellet UO2 fuel Zircaloy-4 ZIRLO Optimized ZIRLO AXIOM LTR-NRC-22-40, Enclosure 2 Page 4 of 7
4 Westinghouse Non-Proprietary Class 3
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Topical Report WCAP-18546-P
- WCAP-18546-P was submitted in March 2021 to request approval for use of AXIOM cladding in all currently approved PWR fuel designs.
- Initial Burnup Limits up to 62 GWd/MTU
- Includes new fuel performance models for AXIOM cladding strength, fuel rod growth, cladding creep and fuel rod corrosion.
- Enables performance benefits by providing:
Lower corrosion and hydrogen pickup at higher burnup Enhanced dimensional stability
- Properties and performance of AXIOM cladding incorporated into existing NRC-approved analytical methods for use in plant-specific safety analyses.
LTR-NRC-22-40, Enclosure 2 Page 5 of 7
5 Westinghouse Non-Proprietary Class 3
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Topical Report WCAP-18546-P Status
- NRC reviewers conducted a technical audit in October and November of 2021
- A supplement was submitted to provide the necessary data for use of AXIOM cladding with ADOPT fuel
- Westinghouse provided responses to Requests for Additional Information (RAIs) on the following areas:
- AXIOM material properties and performance
- Fuel rod design models
- Criteria and methods used for LOCA, reactivity insertion accident (RIA), seismic and other accidents
- The draft Safety Evaluation Report for WCAP-18546 was received on September 2, 2022 and Westinghouse has provided comments LTR-NRC-22-40, Enclosure 2 Page 6 of 7
6 Westinghouse Non-Proprietary Class 3
© 2022 Westinghouse Electric Company LLC. All Rights Reserved.
Summary
- Westinghouse has completed AXIOM cladding material development based on ZIRLO and Optimized ZIRLO cladding
- Topical report is under NRC review. Final SER is expected in 2022 in support of full region implementation
- Supplement on AXIOM cladding for higher burnups to be submitted AXIOM is in the process of being licensed and implemented for PWR fuel LTR-NRC-22-40, Enclosure 2 Page 7 of 7
U. S. NUCLEAR REGULATORY COMMISSION STAFFS EVALUATION OF WESTINGHOUSE ELECTRIC COMPANY TOPICAL REPORT WCAP-18546-P/NP, WESTINGHOUSE AXIOM CLADDING FOR USE IN PRESSURIZED WATER REACTOR FUEL Mathew Panicker, Joseph Messina Nuclear Methods and Fuel Analysis Division of Safety Systems Advisory Committee on Reactor Safeguards Subcommittee Meeting Open Session October 4, 2022 1
=
Background===
WEC submitted WCAP-18546-P/NP, Westinghouse AXIOM Cladding for Use in Pressurized Water Reactor Fuel topical report (TR) to the U. S.
Nuclear Regulatory Commission (NRC) in March 2021
The TR includes:
Density and microstructure of AXIOM cladding Thermal properties Mechanical properties Irradiation programs and operating experience AXIOM cladding behavior: corrosion, hydrogen pickup, rod axial growth, cladding irradiation creep, Impact on rod ejection accident (REA)
Irradiated mechanical properties: axial and ring tensile tests Licensing Criteria: fuel rod design, safety analyses - loss-of-coolant accident (LOCA), non-LOCA, containment integrity Beginning of life (BOL) and end of life (EOL) seismic-LOCA evaluation Nuclear design, thermal-hydraulic design Radiological consequence analysis 2
Overview and History Acceptance review was performed by the NRC staff Regulatory audit (virtual) was conducted in October 2021 through the electronic reading room During the audit open items were generated, interim responses were received, and requests for additional information (RAIs) preparations started RAI responses were received in February 2022 Westinghouse submitted a supplement to WCAP-18546-P/NP to extend the applicability to ADOPT fuel in December 2021 3
Regulatory Evaluation GDC 10: acceptable fuel design limits not exceeded during normal operation and anticipated operational occurrences 10 CFR 50.46(a)(1)(i): Each boiling or pressurized light-water nuclear power reactor fueled with uranium oxide pellets within cylindrical zircaloy or ZIRLO cladding must be provided with an emergency core cooling system (ECCS) that must be designed so that its calculated cooling performance following postulated loss-of-coolant accidents conforms to the criteria set forth in paragraph (b) of this section Requirements for analyzing the design-basis loss-of-coolant accident (LOCA) are contained within Appendix K to 10 CFR Part 50, 10 CFR 50.46, and GDC 35 GDC 35: abundant core cooling sufficient to (1) prevent fuel and cladding damage that could interfere with effective core cooling and (2) limit the metal-water reaction on the fuel cladding to negligible amounts 4
AXIOM Cladding Fuel Thermal and Mechanical Properties WCAP-18546-P/NP TR provides information on:
Microstructure
Microhardness
Phase transition temperatures
Texture and contractile strain ratio
Specific heat
Thermal conductivity
Melting temperature
Thermal expansion
Elastic moduli, Poissons ratio
Creep and hardening, Fatigue
Emissivity
High temperature metal-water reaction, Hydride reorientation
Irradiation programs and experience 5
Characterization of AXIOM Cladding Fuel Performance and Licensing Criteria
Fuel rod axial growth
Corrosion Models, hydrogen pickup
Impact on REA limits
Fuel performance and licensing
Cladding stress
Cladding strain
Fuel rod internal pressure
Fuel Clad Wear
Cladding fatigue
Cladding oxidation
Cladding hydrogen pickup
Cladding flattening
Cladding free standing
Pellet overheating
Pellet-cladding interaction
Interface to other safety analyses: LOCA, non-LOCA, radiological consequences 6
AXIOM Fuel Conclusions TR provides sufficient information on properties and characterization of AXIOM cladding fuel The NRC staff reviewed AXIOM fuel rod design criteria, and safety analyses for both LOCA and non-LOCA methodologies 7