ML25063A196
| ML25063A196 | |
| Person / Time | |
|---|---|
| Issue date: | 02/06/2025 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| NRC-0197 | |
| Download: ML25063A196 (1) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Docket Number:
(n/a)
Location:
teleconference Date:
Thursday, February 6, 2025 Work Order No.:
NRC-0197 Pages 1-12 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 722ND MEETING 4
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5
(ACRS) 6
+ + + + +
7 THURSDAY 8
FEBRUARY 6, 2025 9
+ + + + +
10 The Advisory Committee met via 11 Video/Teleconference, at 8:30 a.m. EST, Walter L.
12 Kirchner, Chair, presiding.
13 COMMITTEE MEMBERS:
14 WALTER L. KIRCHNER, Chair 15 GREGORY H. HALNON, Vice Chair 16 DAVID A. PETTI, Member-at-Large 17 RONALD G. BALLINGER, Member 18 VICKI M. BIER, Member 19 VESNA B. DIMITRIJEVIC, Member 20 CRAIG D. HARRINGTON, Member 21 ROBERT P. MARTIN, Member 22 SCOTT P. PALMTAG, Member 23 THOMAS E. ROBERTS, Member 24 MATTHEW W. 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 CONSULTANTS:
1 STEPHEN P. SCHULTZ 2
DENNIS C. BLEY 3
4 DESIGNATED FEDERAL OFFICIALS:
5 QUYNH NGUYEN 6
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
3 P-R-O-C-E-E-D-I-N-G-S 1
8:31 a.m.
2 CHAIR KIRCHNER: Good morning. The 3
meeting will now come to order. This is the second 4
day of the 722nd meeting of the Advisory Committee on 5
Reactor Safeguards, ACRS. I'm Walt Kirchner, Chairman 6
of the ACRS.
7 ACRS members in attendance in person are 8
Ron Ballinger, Greg Halnon, Craig Harrington, Robert 9
Martin, Scott Palmtag, and David Petti. Members 10 attending virtually are Vicki Bier, Thomas Roberts, 11 and Matt Sunseri and Vesna Dimitrijevic. We also have 12 in-person presence of our consultant Stephen Schultz, 13 and I expect that --
14 VICE CHAIR HALNON: Dennis is on.
15 CHAIR KIRCHNER: Our consultant Dennis 16 Bley is on virtually. Excellent. If I missed anyone, 17 please speak up.
18 Not hearing anything, Michael Snodderly of 19 the ACRS staff is the Designated Federal Officer for 20 this morning's full Committee meeting. No member 21 conflicts of interest were identified. And I know 22 that we have a quorum.
23 The ACRS was established by statute and is 24 governed by the Federal Advisory Committee Act, or 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
4 FACA. The NRC implements FACA in accordance with our 1
regulations.
Per these regulations and the 2
Committee's bylaws, the ACRS speaks only through its 3
published letter reports. All member comments should 4
be regarded as only the individual opinion of that 5
member and not a Committee position.
6 All relevant information related to ACRS 7
activities, such as letters, rules for meeting 8
participation, and transcripts are located on the NRC 9
public website and can be easily found by typing About 10 Us ACRS in the search field on NRC's home page.
11 The ACRS, consistent with the Agency's 12 value of public transparency in regulation of nuclear 13 facilities, provides opportunity for public input and 14 comment during our proceedings. We have received no 15 written statements or requests to make an oral 16 statement from the public.
- However, written 17 statements may be forwarded to today's Designated 18 Federal Officer. We have also set aside time at the 19 end of this meeting for public comments.
20 A transcript of the meeting is being kept 21 and will be posted on our website. When addressing 22 the Committee, the participants should first identify 23 themselves and speak with sufficient clarity and 24 volume so that they may be readily heard. If you'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
5 not speaking, please mute your computer on Teams. If 1
you're participating by phone, please press star-6 to 2
mute your phone and star-5 to raise your hand on 3
Teams. The Teams chat feature will not be available 4
for use during the meeting.
5 For everyone in the room, please put all 6
your electronic devices in silent mode and mute your 7
laptop microphone and speakers. In addition, please 8
keep sidebar discussions in the room to a minimum 9
since the ceiling microphones are live. For the 10 presenters, your table microphones are unidirectional, 11 and you'll need to speak into the front of the 12 microphone to be heard online. Finally, if you have 13 any feedback for the ACRS about today's meeting, we 14 encourage you to fill out the public meeting feedback 15 form on the NRC's website.
16 During this morning's
- meeting, the 17 Committee will consider the following topics. First 18 up will be NuScale loss of coolant accident evaluation 19 model topical report, and then we'll continue our 20 deliberations on two letter reports, one for Reg Guide 21 3.78 and the other on the increased enrichment 22 rulemaking.
23 And with that, since I am the Subcommittee 24 Chair for NuScale, I'm going to turn to Bob Martin, 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 who is the lead on the Committee's review of the LOCA 1
evaluation model or topical report. So, with that, 2
I'll turn to Bob Martin.
3 MEMBER MARTIN: All right. Thanks, Paul.
4 Of course, I have a prepared summary that's been put 5
together here in the last few weeks for the conclusion 6
of our engagement with NuScale. I will begin by 7
referring to myself in third person, so I don't want 8
anyone to get confused or find otherwise awkward. But 9
here it goes.
10 Member Martin reviewed NuScale's topical 11
- report, TR-0516-49422, Loss-of-Coolant Accident 12 Evaluation Model Revision 3, detailing the design 13 basis LOCA evaluation, which is used to analyze 14 emergency core cooling system performance in the 15 water-cooled 250-megawatt thermal NuScale power module 16 for NMP-20.
17 A March 25, 2020, Committee letter 18 concluded that a previous revision of this TR -- the 19 staff-imposed limitations and conditions provided an 20 acceptable methodology for analyzing early-stage LOCAs 21 and NuScale's 160-megawatt thermal NPM-160 and the 22 NPM-20 LOCA, resulting from either an inadvertent 23 opening of an RPV valve or pipe breaks. Inside 24 containment begins with a reactor coolant system 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 breach that releases coolant into the surrounding 1
containment vessel. For the module protection system, 2
or MPS, activates emergency core cooling system by 3
opening reactor vent and recirculation valves, 4
commonly referred to as RVVs or RRVs, maintaining 5
coolant inventory well above the active core region.
6 On January 15th, 2025, three weeks ago, 7
NuScale and NRC staff presented the TR's merits to the 8
Committee for LOCA analysis supporting ECCS 9
assessments, in alignment with Regulatory Guide 1.203, 10 10 CFR 50, Appendix K, and general design criteria 35, 11 or GDC 35, which relates to ECC --
12 The presentations addressed features of 13 NuScale's LOCA EM for estimated collapse liquid level 14 above the fuel and minimum critical heat flux ratio, 15 as impacted by design changes between NPM-160 and NPM-16
- 20. Additionally, the revised TR now includes a 17 containment vessel pressure and temperature response 18 analysis, adhering to GDC 16, 38, and 50, addressing 19 its ability to ensure structural integrity and leak 20 tightness, accommodate energy releases, and manage 21 heat removal and withstand dynamic effects and 22 environmental conditions during LOCAs.
23 The NPM-20 preserves a module's basic 24 design with adjusted operating conditions, including 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 increased primary pressure, T av control replacing T 1
hot control, a reduced feedwater temperature, and a 2
lower minimum critical temperature.
3 Containment design parameters were 4
enhanced with design pressure and temperature 5
increased to 1,200 PSI and 600 F respectively. ECCS 6
valves, i.e., the RVVs and RRVs, have been redesigned 7
to ensure reliable depressurization capability via 8
resizing and the addition of trip valves and low 9
venturis. The RVVs no longer include the inadvertent 10 actuation block valves.
11 NuScale and NRC staff presented the 12 incremental impact of these design changes on LOCA EM.
13 Design changes had little effect on NuScale's local 14 phenomena identification and ranking table, i.e.,
15 PIRT. We did require updates to their NRElAP5 thermal 16 hydraulic systems code, an additional validation 17 assessment from their NIST-2 test facility. Those 18 changes were limited to those necessary for general 19 maintenance and to address NPM-160 to NPM-20 20 differences, including an improved CH --
21 The NPM-20 NRELAP5 model also employs 22 features beyond 20 CFR 50, Appendix K,
to 23 conservatively calculate figures of merit.
24 The Committee concludes that while the TR 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 introduces several EM changes to accommodate the NPM-1 20 design, it remains sufficiently complete and 2
accurate for verifying the adequacy of the ECCS 3
performance for the uprated design during design-bases 4
5 This conclusion is supported by the 6
following: one, the design changes are incremental 7
and aligned with power uprate; two, EM builds from a 8
previously approved methodology; and three, EM 9
addresses major process and phenomenological 10 uncertainties and retains the conservative features 11 required by 10 CFR 50, Appendix K, as applicable to 12 the NPM-20 implying a subset of the -- of what 13 otherwise appears in Appendix K. Furthermore, the 14 staff's L&Cs, limitations and conditions, most of 15 which are carried forward from prior EM, remain 16 relevant and appropriate.
17 Member Martin recommends that the 18 Committee not object to the staff issuing the safety 19 evaluation report on the revised topical report. It 20 is also recommended that this write-up serve as the 21 record of the Subcommittee meeting and an ACRS letter 22 report not be prepared.
23 I might add that the proceedings that 24 we've had benefitted from some engagement with 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
10 applicant to highlight what we thought was 1
particularly important from a safety perspective. And 2
certainly, as the lead on this, I really appreciated 3
that engagement --
4 CHAIR KIRCHNER: Members' comments?
5 I have one, Bob, and that is -- you say it 6
later on. The figures of merit are keeping the 7
collapse liquid level of the active core, and the 8
other one is damage the minimum critical heat flux 9
ratio. You do point those figures of merit out later.
10 Could we just move that up to that first paragraph and 11 point out that those are the metrics?
12 MEMBER MARTIN: Oh, yeah. I have no 13 problem editing this. I can get that to Larry -- I 14 mean, this will be a piece for discussion tomorrow.
15 I don't think we'll reread it tomorrow. But we can 16 make the edit that you're suggesting here.
17 CHAIR KIRCHNER: Yeah.
18 MEMBER MARTIN: Yeah.
19 CHAIR KIRCHNER: Thank you for that.
20 If there are no further comments, then we 21 will --
22 MEMBER SUNSERI: Hey, this is Matt. I 23 have just a question for him.
24 CHAIR KIRCHNER: Yeah, go ahead, Matt.
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 MEMBER SUNSERI: So, I mean, why are we 1
doing this this way versus the memo format that we do 2
for other chapters? I'm just curious.
3 MEMBER MARTIN: This is not a chapter.
4 This is actually a TR. So we will have a chapter --
5 is it April that we'll have a meeting on the Chapter 6
15? So yes. There will be a memo.
7 MEMBER SUNSERI: Okay.
8 MEMBER MARTIN: On this -- this was Matt, 9
in lieu -- because we had a placeholder in our -- we 10 set the agenda, because of the FRN requirements, a 11 month in advance. So we put a placeholder on the 12 agenda for this morning in case we might decide -- the 13 Committee might decide to write a letter report.
14 The recommendation from the Subcommittee 15 was not to, unless the Committee members present this 16 morning wish otherwise. Please advance that opinion.
17 Otherwise, we will just do as we indicated, P&P to 18 make this part of the summary meeting record.
19 MEMBER SUNSERI: Thank you.
20 MEMBER ROBERTS: Yeah, this is Tom. To 21 answer Matt's question, I think the distinction is if 22 the staff intends to approve the topical report in 23 advance of the application, then they would need to 24 have this kind of write-up from us to document that we 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 don't object to issuing the topical. So I don't know 1
if the intent is to issue this topical in advance of 2
the FSER approval, but if it is, then I think that 3
would be a reason to have the separate memo.
4 CHAIR KIRCHNER: Any further discussion?
5 Okay. Thank you, Bob.
6 With that, I would Like to suggest that we 7
move on to our letter report for Reg Guide 3.78.
8 Tammy, are you able to pull that most 9
recent version -- Reg 3, I think, is the latest 10 version -- Reg 4. Sorry.
11 MR. BURKHART: Yes -- and this is Larry 12 Burkhart. I believe we don't need the court reporter 13 anymore. Toby, we don't need you for the rest of the 14 day, nor the rest of this meeting.
15 CHAIR KIRCHNER: That's correct. Yeah.
16 MR. BURKHART: Thank you, Toby.
17 CHAIR KIRCHNER: Yes. Thank you for your 18 service.
19 (Whereupon, the above-entitled matter went 20 off the record at 8:45 a.m.)
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