ML25063A195
| ML25063A195 | |
| Person / Time | |
|---|---|
| Issue date: | 02/05/2025 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| NRC-0197 | |
| Download: ML25063A195 (1) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Docket Number:
(n/a)
Location:
teleconference Date:
Wednesday, February 5, 2025 Work Order No.:
NRC-0197 Pages 1-89 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 1
2 3
4 5
6 7
8 9
10 11 12 13 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
+ + + + +
722ND MEETING ADVISORY COMMITTEE ON REACTOR SAFEGUARDS (ACRS)
+ + + + +
WEDNESDAY FEBRUARY 5, 2025
+ + + + +
The Advisory Committee met via Video/Teleconference, at 8:30 a.m. EST, Walter L.
Kirchner, Chair, presiding.
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
10 ALSO PRESENT:
11 PHILIP A. BENAVIDES, NMSS/REFS/RRPB 12 THERESA V. CLARK, NRR/DSS 13 JAMES R. CORSON, JR., RES/DSA/FSCB 14 AL CSONTOS, Nuclear Energy Institute 15 ELIJAH D. DICKSON, NRR/DRA/ARCB 16 DARRELL S. DUNN, NMSS/DFM/MSB 17 SCOTT T. KREPEL, NRR/DSS/SFNB 18 EDWIN LYMAN, Union of Concerned Scientists 19 JOSEPH MESSINA IV, NRR/DSS/SFNB 20 CHARLEY A. PEABODY, JR., NRR/DSS/SNSB 21 JASON M. PIOTTER, NMSS/DFM/NF 22 DAVID L. RUDLAND, NRR/DRNL 23 JAMES STAVELY, PSEG Nuclear 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 CONTENTS 1
PAGE 2
- 1) Opening Remarks by the ACRS Chairman 3
1.1) Opening statement 4
4 1.2) Agenda and items of current interest.
4 5
6
- 2) Regulatory Guide (RG) 3.78, Revision 0, 7
Regarding Acceptable ASME Section XI 8
Inservice Inspection Code Cases for 9
10 CFR Part 72 10 2.1) Remarks from Subcommittee Chair 7
11 2.2) Discussions with the NRC Staff and 12 other stakeholder and Committee 13 discussion.............. 13 14 2.3) Committee deliberation (off record)
. 17 15 16
- 3) Increased Enrichment Draft Rule Language and 17 Associated Draft RGs Including RG 1.183, Revision 2 18 3.1) Remarks from the Subcommittee Chair
. 17 19 3.2) Presentations and discussions with 20 NRC Staff
.............. 19 21 22 Adjourn 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
4 P-R-O-C-E-E-D-I-N-G-S 1
8:30 a.m.
2 CHAIR KIRCHNER: Good morning. The meeting 3
will now come to order. This is the first day of the 4
722nd meeting of the Advisory Committee on Reactor 5
Safeguards, ACRS. I am Walt Kirchner, Chair of the 6
ACRS.
7 ACRS members in attendance, in person, are 8
Ron Ballinger, Greg Halnon, Robert Martin, Scott 9
Palmtag, Dave Petti, Thomas Roberts, Craig Harrington 10 and Vicki Bier. ACRS Members in attendance virtually 11 via Teams are Matt Sunseri and Vesna Dimitrijevic. We 12 also have with us, our consultant Steve Schultz. And 13 online our Consultant Dennis Bley. I've missed anyone 14 please speak up. Hearing no one, okay.
15 Christopher Brown and Weidong Wang of the 16 ACRS Staff are the designated federal officers for the 17 first and second portions of this mornings full 18 committee meeting. I know that we have a quorum.
19 Our first topic is Reg Guide 3.78 and ASME 20 Code Cases. Member Harrington recused himself due to 21 potential conflict of interest on this topic.
22 The ACRS was established by statute and is 23 governed by the Federal Advisory Committee Act, or 24 FACA. The NRC implements FACA in accordance with our 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 regulations. Per these regulations, and the 1
Committee's bylaws, the ACRS speaks only through its 2
published reports therefore all Member comments should 3
be regarded as only the individual opinion of that 4
Member and not a Committee position.
5 All relevant information related to ACRS 6
activity, such as letters, rules for meeting 7
participation and transcripts are located on the NRC 8
public website and can be easily found upon typing 9
about us ACRS in the search field on the NRC's home 10 page.
11 The ACRS, consistent with the Agency's 12 value of public transparency and regulation in nuclear 13 facilities provides opportunity for public input and 14 comment during our proceedings. We have received no 15 statements for a request to make an oral statement 16 from the public, however, we set aside time at the end 17 of this meeting for public comments. Written 18 statements may be forwarded to today's designated 19 federal officers. The transcript of the meeting is 20 being kept and will be posted on our website.
21 When addressing the Committee, the 22 participants should first identify themselves and 23 speak with sufficient clarity and volume so that they 24 may be readily heard. When you're not speaking please 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 mute your computer on Teams. If you are participating 1
by phone, please press *6 to mute your phone. And *5 2
to raise your hand on Teams. The Teams chat feature 3
will not be available for use during the meeting.
4 For everyone in the room, please put all 5
your electronic devices in silent mode and mute your 6
laptop microphone and speakers. In addition, please 7
keep sidebar discussions in the room to a minimum 8
since the ceiling microphones are live, and they're 9
actually quite sensitive.
10 For the presentators, your table 11 microphones are unidirectional and you'll need to 12 speak into the front of the microphone to be heard 13 online. Finally, if you have any feedback for the 14 ACRS about today's meeting, we encourage you to fill 15 out the public meeting feedback form on the NRC's 16 website.
17 During today's meeting the Committee will 18 consider these topics. The Regulatory Guide 3.78, 19 Revision 0, Regarding Acceptable ASME Section XI, In-20 Service Inspection Code Cases for 10 CFR Part 72, 21 increase enrichment, the second topic will be 22 Increased Enrichment Draft Rule Language and 23 Associated Draft Reg Guides to implement it, including 24 Reg Guide 1.183, Revision 2.
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 And with that, are there any opening 1
statements or comments from Members? If not, then let 2
me turn the Committee's deliberations over to our 3
Fuels, Materials and Structures Subcommittee Chair, 4
Ron Ballinger. Ron.
5 MEMBER BALLINGER:
Thank
- you, Mr.
6 Chairman. So we had a Subcommittee meeting on this 7
topic on the, in December, I think it was December 8
18th, where we got presentations from the Staff 9
related to this new reg guide, soon to be reg guide, 10 related to inspection requirements for dry cask 11 storage. Dry storage casks.
12 And as a result of that the Committee 13 decided that we would write a letter, but that we 14 would not require a presentation from the Staff at 15 this meeting that are here. And that that would be, 16 that would be how we would proceed.
17 The proposed rule basically identifies a 18 code, an ASME code case, which could be used for 19 defining the inspection intervals of these casks with 20 one exception. In that, instead of allowing for 20 21 years between inspections under certain conditions, as 22 defined in a very, very good EPRI report, under 23 certain conditions where you really don't have any 24 environment where that's going to be a problem you can 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 extend that inspection interval to 40 years. So 1
that's the key. And the key report, there's an EPRI 2
document which is referenced in this proposed letter, 3
which is the key, the key document.
4 So I guess the path forward, what we 5
thought we would do is just read it in.
6 CHAIR KIRCHNER: Yes, sir.
7 MEMBER BALLINGER: And I don't know, I 8
have a draft paper copy in front of me because my 9
computer is frozen and Word will not open. So if we 10 can bring it up on the screen.
11 (Off microphone comments.)
12 MEMBER BALLINGER: We ready to go?
13 CHAIR KIRCHNER: Yes. Go ahead, Ron.
14 MEMBER BALLINGER: Okay. I won't deal 15 with the subject title and everything.
16 During the 722nd meeting of the Advisory 17 Committee on Reactor Safeguards, February 5 through 7, 18 2025, we completed our review of Regulatory Guide 19 3.78, acceptable ASME Section 11, in-service 20 inspection code cases for Title 10 of the Code of 21 Federal Regulations 10 CFR Part 72. Our fuels, 22 materials and structures subcommittee also reviewed 23 this matter on December 18th, 2024. During these 24 meetings we had the benefit of discussions 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
9 Nuclear Regulatory Commission Staff, Nuclear Energy 1
Institute and the Electric Power Research Institute.
2 We also had the benefit of reference documents.
3 Conclusion and recommendation. Reg Guide 4
1.78, Revision 0 provides methods and procedures in 5
accordance with the American Society of Mechanical 6
Engineers, ASME. Codes are acceptable for in-service 7
inspection of independent spent fuel storage 8
installation, ISFSIs, and other licensed certificate 9
of compliance holders to comply with 10 CFR 72.42 and 10 Part 240.
11 The Committee agrees that these methods 12 and procedures are reasonable and appropriate. Number 13 two, the reg guide should be issued.
14 Background and discussion. The Staff 15 proposed to issue Reg Guide 3.78, Revision 0 that 16 identifies methods and procedures consistent with the 17 ASME Code that would be acceptable for in-service 18 inspection of ISFSIs and other CoC holders related to 19 10 CFR 72.42 and Part 240.
20 The proposed reg guide specifies Section 21 11, code cases that would be acceptable. In 22 particular this initial, the initial version of the 23 proposed reg guide endorses the use of ASME code case 24 N-860, inspection requirements and evaluation 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 standards for spent nuclear fuel storage and 1
transportation containment system Section XI, Section 2
XI, Division 1,Section XI, Division 2 with an 3
additional allowance for a 40 year inspection interval 4
if particular conditions are met.
5 ASME Code Case N-860 "provides the 6
requirements for inspection intervals and inspection 7
populations following both the additional inspection 8
after entering the storage period of operation and 9
subsequent inspections at the specified intervals."
10 The requirements are defined based on the 11 susceptibility of ISFSI sites, the chloride-induced 12 stress corrosion cracking, CISCC. Which is determined 13 using the methodology described in EPRI report, 14 susceptibility assessment criteria for chloride-15 induced stress corrosion cracking of weld and 16 stainless canisters for dry storage systems EPRI 17 3002005371.
18 The susceptibility ranking ranges from 1 19 to 3, very low probability of CISCC. With 7 to 10 20 very high susceptibility. For ISFSI sites with a 21 chloride susceptibility of 7 below, decreases in the 22 inspection intervals and decreases when the inspected 23 populations are allowed, depending on the results of 24 a screening examination described in Code Case 860, 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 Subarticle 2200, with the stipulation that maximum 1
inspection interval is 20 years and the minimum 2
inspection population is one canister per ISFSI site.
3 However, Subarticle 2700 does not allow increases in 4
the inspection interval or decreases in the inspection 5
population for ISFSIs sites which have a ranking of 8 6
and above. 8 is highly susceptible.
7 The requirements of Code Case N-860 are in 8
general agreement with the following. NUREG-1927, 9
standard review plan for renewal of specific licensees 10 and certificates of compliance for dry storage or 11 spent nuclear fuel, provides guidance for the NRC 12 safety review of renewal applications for ISFSI 13 specific licensees and CoCs for spent fuel storage 14 cask designs.
15 NUREG-2214, managing aging process and 16 storage provides a generic technical basis for renewal 17 of ISFSI specific licensees and CoCs for spent fuel 18 storage cask designs. The approval of Code Case N-860 19 is in the proposed reg guide. Also as considered, 20 international standards. Including IAEA SSR-4, safety 21 of nuclear fuel cycle facilities and IAEA SSG-15, 22 storage of spent nuclear fuel.
23 With regard to the required inspection 24 intervals the approval of Code Case N-860 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
12 proposed reg guides provides an alternative to the 1
Code Case allowing an increased inspection interval 2
beyond 20 years. Under this alternative the canister 3
inspection interval may be increased to a maximum of 4
40 years provided that the ISFSI site meets both of 5
the following site conditions below. The ISFSI site 6
must have a CISCC susceptibility ranking of 3 of below 7
as determined using the criteria in this EPRI 8
document. All other requirements of the code case are 9
satisfied.
10 Note that an inspection interval of 40 11 years coincides with the CoC time period. In other 12 words, the Committee considering the underlying 13 environment degradation concerns available, testing 14 and analytical results and risk evaluations and finds 15 that the requirements reflected in Code Case N-860, as 16 well as the alternative inspection interval included 17 in the proposed reg guide to be reasonable and 18 appropriate.
19 Summary. Proposed reg guide provides 20 methods and procedures in accordance with ASME code 21 that would be acceptable for in-service inspection, 22 ISFSIs and other license CoC holders to comply with 10 23 CFR Sections 72.42 and 240. The Committee agrees that 24 these methods and procedures are reasonable and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
13 appropriate. The reg guide should be issued. We are 1
not requesting a formal response from the Staff to 2
this letter report. Sincerely Walt Kirchner.
3 CHAIR KIRCHNER: Thank you, Ron. Members, 4
high level comments? Not hearing anyone volunteering 5
any major critiques, Ron.
6 MEMBER BALLINGER: If you wait long 7
enough.
8 CHAIR KIRCHNER: Well, when we get to the 9
word-by-word, line-by-line we'll probably have some 10 input. What about the concludes and recommendations, 11 could we see those, Tammy, please?
12 One thing we, if I remember back to the 13 discussion after the presentations from the Staff, I 14 know we talked about, we didn't talk about risk per 15 se, but we talked about the overall safety of the 16 canisters that are out there, deployed, such. I know 17 this is focused on the reg guide, it's not an 18 assessment of the storage sites itself. Is there any 19 comment on risk significance warranted here? I know 20 you've held forth on this topic in the past.
21 MEMBER BALLINGER: There are, on the 22 order, and the Staff can correct me if I'm wrong, 23 there are at least 2,000 canisters out there. Is that 24 about right?
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 MR. DUNN: Darrell Dunn, NRC Division of 1
Fuel Management. It's actually closer to 4,000.
2 MEMBER BALLINGER: Close to 4,000. Some 3
of them are 20 years old.
4 CHAIR KIRCHNER: Right.
5 MEMBER BALLINGER: We've had zero leaks.
6 CHAIR KIRCHNER: Yes.
7 MEMBER BALLINGER: In welded canisters.
8 Got to keep careful here. And the EPRI document 9
that's referenced here really does a great job at not 10 only discussing that but identifying the 11 susceptibility. The risk.
12 CHAIR KIRCHNER: Yes. Now the reason I 13 raised it is that this will obviously, go also up into 14 the Commission, Commissioner Offices. And if we 15 wanted to venture further than the reg guide and make 16 any statement along those lines I was wondering 17 whether that would be appropriate as part of this.
18 VICE CHAIR HALNON: I was wondering also 19 if this is an opportunity to say it's a good example 20 of operating experience, Industry, what you call the 21 EPRI reports, but research, Industry research and a 22 risk-informed approach to regulation where it all came 23 together in this to establish a framework that is much 24 more amenable to the --
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
15 MEMBER BALLINGER: I'd be happy to do 1
that. If this is a pet peeve by the way.
2 VICE CHAIR HALNON: Well I was -
3 MEMBER BALLINGER: But I restrained myself 4
from launching off into something that has nothing to 5
do with the reg guide.
6 VICE CHAIR HALNON: Well it's more of a -
7 CHAIR KIRCHNER: Intentional --
8 VICE CHAIR HALNON: -- a comment from the 9
standpoint of a less, acknowledging that this was a 10 nice job, if you will, of bringing in the factors of 11 all these experience, research and regulation, putting 12 them together in a risk-informed way and coming out 13 with a good product. That seems to be -
14 MEMBER BALLINGER: You mean as part of a 15 conclusion?
16 VICE CHAIR HALNON: Either a conclusion or 17 maybe in the summary. It doesn't necessarily, I mean, 18 I guess it's one of the same in our letters but -
19 MEMBER MARTIN: You could do something 20 simple Like, that last one is obviously pretty terse.
21 You could just say, you reg guide to be sound, risk-22 informed, appropriate or release, and you sneak in 23 risk-informed.
24 MEMBER BALLINGER: I'm happy to do that.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
16 That's a good, these are good comments.
1 VICE CHAIR HALNON: Just kind of, just 2
keying off of Walt's discussion. I kind of popped in 3
my head, I was looking at the slides and it just seems 4
Like all the things came together here. You know, the 5
research and the operating experience and the 6
practicality of inspections. And it just seemed to 7
come together into a good bowl of risk-informed 8
approach to regulations.
9 MEMBER BALLINGER: Yes. I mean, this 10 would be an expansion. I'd be happy to do that.
11 Happy, you know, happy to do that. It's not a line-12 by-line issue but --
13 VICE CHAIR HALNON: No. It also means 14 paragraph and the letter.
15 MEMBER BALLINGER: Yes.
16 CHAIR KIRCHNER: Yes.
17 MEMBER BALLINGER: Yes.
18 VICE CHAIR HALNON: A couple lines. I 19 mean, yes, a couple lines. And then Bob's suggestion 20 about just mentioning it in the Number 2 there --
21 MEMBER BALLINGER: Yes.
22 VICE CHAIR HALNON: -- as a prelude to 23 the, this reg guide should be issued --
24 MEMBER BALLINGER: Okay.
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 VICE CHAIR HALNON: -- works.
1 MEMBER BALLINGER: I'm happy to do that.
2 I'll have to have a backup for this because I might 3
not survive the next rule.
4 (Laughter.)
5 CHAIR KIRCHNER: Pardon this interruption.
6 Would the court reporter, since we are deliberating 7
now on the letter, we don't need a transcription of 8
our conversation so I think, we expect --
9 MR. BURKHART: 10:30 So, this is Larry 10 Burkhart. If you can come back at 10:30 for the 11 increased enrichment topic, Toby? Toby, can you hear 12 me? Okay, so we can stop --
13 COURT REPORTER: Yes, I can hear you. So 14 this is off the record. I come back at 10:30?
15 MR. BURKHART: Yes. At 10:30, yes.
16 (Whereupon, the above-entitled matter went 17 off the record at 8:51 a.m. and resumed at 10:38 a.m.)
18 CHAIR KIRCHNER: Okay, we're back in 19 session. And we're going to turn to the topic of 20 increased enrichment. And I will turn, once again, to 21 Ron Ballinger.
22 MEMBER BALLINGER: Thank you, Mr. Chair.
23 Well, here we are at the beginning of the beginning.
24 Which is probably a better way to put it. We've had 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 multiple meetings, multiple discussions and I think 1
they've actually been very, very good. So we're 2
planning on writing a letter, we will be writing a 3
letter on this but we should, Theresa, you want to say 4
something?
5 MS. CLARK: I'm happy to you, if you'll 6
allow it.
7 (Laughter.)
8 MEMBER BALLINGER: We're always happy.
9 MS. CLARK: My pleasure. So, hi everyone.
10 This is Theresa Clark from the Division of Safety 11 Systems. I've been speaking at some of these 12 meetings. It's a slightly different audience, at 13 least in person.
14 So I'll just reemphasize perhaps, for the 15 record, how proud I am of the Staff who've been 16 working on this. How important this role is to both 17 the Agency and to the Industry that's looking forward 18 to adopting it. And the obvious tensions in all of 19 the conversations that we've had between, you know, 20 what level of requirements are necessary in the role 21 versus how performance-based we can be putting things 22 in guidance, between getting the best product possible 23 within the impressive schedule that we have set for 24 our self. And a couple at least other intentions that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
19 I forgot here.
1 But we've made our best efforts to think 2
about and reflect on what we've heard to make some 3
reasonable adjustments where we could to make sure 4
that the requirements are just copy/pasted from 5
decades that are right size to the environment that we 6
have today. And so, we go work at sort of a lot of 7
the beginning of the beginning team. We have a 8
product that we think is very good to go out for 9
public engagement, workshops and to really perfect a 10 rule that will advance the adoption of safe technology 11 in the country. So we look forward to that.
12 And as you'll be hearing, there are other 13 things going on too outside the process of the 14 rulemaking and we look forward to continuing those in 15 public engagement too. So thank you for the 16 opportunity, kudos to the Staff.
17 MEMBER BALLINGER: Thank you. So who is 18 controlling what here?
19 MR. BENAVIDES: I guess I am at this 20 point.
21 MEMBER BALLINGER: Okay.
22 MR. BENAVIDES: Next slide, Aaron. You 23 know, once again, thanks for your time. I'm Phil 24 Benavides, project manager in the Office of Nuclear 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 Material Safety Safeguards assigned as project manager 1
for the rulemaking at increased enrichment of 2
conventional accident fuel designs for light water 3
reactors.
4 Today we're going to discuss the draft 5
proposed rule. This discussion will include a brief 6
overview and status in the increased enrichment 7
rulemaking which will lead into brief summaries of the 8
relevant subject matter. From the relevant subject 9
matter experts for each technical topics. With that 10 I'm going to provide their review.
11 Next slide please. As a reminder how we 12 got to this point. I would Like to go back to the 13 beginning when the issue was identified.
14 Throughout the last few years Staff has 15 seen an increased interest from Industry for the use 16 of fuel enriched above 5.0 weight percent uranium-235.
17 The NRC noted that although the current regulatory 18 framework allows for licensing of the fuel above 5.0 19 weight percent, the use of this fuel may result in 20 numerous exemption requests for licensees.
21 So as a proposed solution NRC Staff began 22 pursuing rulemaking rather than licensing by 23 individual exemptions. In December 2021 the Staff 24 provided the Commission SECY-21-0109 requesting 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 approval to begin the rulemaking process.
1 Next slide please. The Commission 2
approved, approval was granted in the SRM, SECY 3 0109 on March of 2022. In this SRM the Commission 4
specified several considerations to evaluate in 5
addition to what was specified in the rulemaking plan.
6 One was that the rule should only apply to 7
high assay low enriched uranium levels. This was done 8
for both non-proliferation and safeguard reasons. And 9
for the Staff to focus on the range of enrichment most 10 likely to be contemplated in future applications. In 11 addition, the Staff was directed to address fuel 12 fragmentation relocation and dispersal and take a 13 risk-informed approach.
14 Next slide please. The NRC issued a 15 regulatory basis on September 8th, 2023. Stakeholder 16 involvement throughout the process including public 17 meetings which were held before the regulatory basis 18 was issued in June of 2022 and after the regulatory 19 basis was issued on October 25th, 2023.
20 The regulatory basis public comment period 21 was open from September 8th, 2023, through January 22 22nd, 2024. In addition to the rulemaking engagement 23 Staff shared fuel dispersal insights at the NRCs 24 annual higher burn-up workshop on September 3rd, 2024.
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 The proposed rule is due to the Commission in March of 1
2025.
2 Next slide please. This slide shows no 3
real rulemaking activity. We're still in the proposed 4
rule package development stage and we're currently on 5
our, currently at the yellow star working on our way 6
towards submission to the Commission in March 2025.
7 After the Commission reviews and approves 8
the proposed rule package the Staff will finalize the 9
proposed rule based on Commission direction. The 10 federal register notice will be issued opening up the 11 proposed rule for public comment indicated by the 12 purple box on the right.
13 After the public comment period closes the 14 Staff will develop the draft final rule package which 15 is expected to be sent to the Commission in September 16 of 2026. I do want to point out that in addition to 17 these ACRS engagements the draft, per the draft 18 proposed rule, Staff plans to present to ACRS again 19 towards the end of the final rule development period 20 prior to the draft final rule being sent to the 21 Commission for consideration.
22 Next slide please. This slide shows the 23 order of the presentators for today. After this 24 overview presentation we'll transition to brief 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
23 overviews on the following topics. Criticality 1
accident requirements, fissile packaging requirements, 2
control room design requirements and fuel 3
fragmentation, relocation and dispersal.
4 I guess before we move on is there any 5
questions on the process?
6 CHAIR KIRCHNER: With your best estimate 7
schedule, when would you come back to the ACRS from 8
that time line?
9 MR. BENAVIDES: Looking at the time line 10 and, you know, we're trying to get to the Commission 11 in September, and so probably in the summer, you know, 12 of I guess 2026 leading, you know, before we send it 13 up to the Commission.
14 CHAIR KIRCHNER: Okay. All right, thank 15 you.
16 MR. BENAVIDES: Yes, you're welcome. I 17 guess with no further questions we can move on to our 18 first technical presenter, Charley Peabody, who is 19 online.
20 MR. PEABODY: All right, thank you, Phil.
21 Next slide please. So I'm just going to give a very 22 brief overview of what we're doing here. We didn't 23 get a lot of questions or feedback on, from the 24 subcommittee because we think that this is one of 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
24 areas that's particularly straightforward in what 1
we're proposing to change.
2 What we're going to do is we're going to 3
amend the existing 5.0 percent weight u-235 limit in 4
50.68(b)(7) and allow for an alternative between that 5
existing 5.0 weight percent or a plant specific 6
criticality safety limit which is based, which will be 7
specified somewhere in the licensees operating license 8
documentation. The licensees will be allowed to 9
increased enriched fuels above 5.0 weight percent as 10 long as the increased enrichment levels approved are 11 specifically in their technical specifications, design 12 features or some other equivalent part.
13 We chose this proposal because it, you 14 know, based on a research study that we did we believe 15 that the existing analyses, which were used under the 16 other paragraphs of 50.68 can be applied to the 17 enrichment levels that are specified without 18 substantive changes to the methodologies. And this 19 would just basically provide a means of getting, 20 getting licensees able to go above 5.0 weight percent.
21 And it will also allow licensees which do not wish to 22 go above 5.0 percent to continue using their existing, 23 their analyses without any particular back fit 24 concerns that arise out of the rulemaking.
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
25 That's all I have. Any questions? Next 1
slide. All right, hearing None --
2 CHAIR KIRCHNER: All right. This is Walt 3
Kirchner --
4 MR. PEABODY: -- I'll turn it over to 5
Jason. Oh, go ahead.
6 CHAIR KIRCHNER: Yes, Charley, before you 7
hand it over, on the analysis methods that you have, 8
or that the applicants are using for criticality 9
safety, is there any, are you seeing any needs for 10 benchmarking or anything to go up to a nominally 8.0 11 percent or you feel the methods are well validated?
12 I'm thinking of NCNP and perhaps other codes that are 13 being used.
14 MR. PEABODY: based on the research study 15 that we did, we were basically utilizing Like the 16 existing absorber, absorber methodologies. So Like 17 adding additional absorption materials. And we, the 18 research study showed that you can basically, you 19 know, by expanding the amount of poisons, whether it's 20 gadolinia or integral fuel burnable absorbers that we 21 can still maintain the decay effective levels and the 22 desired ranges, even all the way up to the higher end 23 of the range of 15 to 20 percent.
24 So I would say that we have very high 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
26 confidence in the up to eight percent range because 1
that would be even less than a change than the 2
bounding cases that we did as part of the ORNL 3
research study.
4 CHAIR KIRCHNER: Okay, thank you.
5 MR. PEABODY: All right, any additional 6
questions? All right, I'll turn it over to Jason 7
Piotter then.
8 MR. PIOTTER: Thank you, Charley. Good 9
morning everyone. Nice to see everyone again. My 10 name is Jason Piotter, I'm the new fuels team leader 11 in NMSS. Former life I was a structural reviewer and 12 a containment reviewer so that's been my role with 13 respect to 10 CFR Part 71 packaging requirements.
14 The bottom line up-front for, next slide 15 please. The bottom line up-front for transportation 16 packages for UF6 is that the current regulations are 17 actually adequate all the way up to 20 weight percent 18 to certify these packages. The applicants can use 19 71.55(b), 71.55© and 71.55(g), in addition to 20 exemptions, to certify their packages. And we do have 21 certified packages currently, all the way up to 20 22 weight percent.
23 Just a reminder for folks that hadn't 24 heard this presentation, or parts of this presentation 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
27 before, the regulations in 10 CFR Part 71 for 1
packaging transportation of the radioactive material 2
in general to not have an enrichment limit 3
requirement. There is one location within 10 CFR Part 4
71 that does have that enrichment limit as part of the 5
rule at 71.55(g). And it is specific only to UF6 6
packages.
7 There is a provision at, in 71.55(g) that 8
allows an exception to the requirement that currently 9
exists in 71.55(b) which requires the consideration of 10 water in leakage when performing criticality 11 evaluations. And the stipulation is, is that the UF6 12 content currently is not enriched to greater than 5 13 weight percent.
14 Next slide. So while our current 15 regulations, as written, are sufficient to transport 16 higher enriched UF6, what we're providing is a 17 nonmandatory modification of the current enrichment 18 limit that allows for more regulatory certainty while 19 maintaining safety.
20 This rulemaking would amend 10 CFR 21 71.55(g) to allow the current exception of UF6 in 22 ratio of up to 5 weight percent to expand to 10 weight 23 percent U-235. In addition, the modified rule would 24 require a defense-in-depth design feature for those 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
28 packages containing UF6 enriched between 5 and 10 1
weight percent U-235.
2 And again, just as a closing idea, the 3
purpose for taking a balanced approach with this, had 4
a bunch of various reasons for it, but primarily it 5
had to do with, again, maintaining that we had 6
regulatory certainty and regulatory flexibility 7
maintained and balanced. Take that in conjunction 8
with the fact that we can certify packages all the way 9
up to 20 percent currently, the Staff did not feel it 10 was warranted that we would go fully up to 20 weight 11 percent.
12 We do have a question, however, out to the 13 public to provide additional specific feedback on this 14 point so that we get additional public and stakeholder 15 input to this enrichment level, enrichment level that 16 we chosen for the proposed rule. That's all I have 17 for the presentation. Any questions?
18 CHAIR KIRCHNER: Jason, what would be a 19 typical defense-in-depth measure, as you went up to 10 20 percent?
21 MR. PIOTTER: What we've seen in the past 22 for UF6 packages, currently the rule has a performance 23 requirement that during the hypothetical accident 24 conditions no part of the packaging can impact 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
29 valve. What we would expect to see is some sort of 1
valve protection device, in addition to have a 2
requirement where on impact you would get no part of 3
the packaging that would get close to the valve.
4 So it would be an additional layer, much 5
Like sort of a shear ring such that if got sort of a 6
guillotine type cut or guillotine type impact it 7
shouldn't shear that valve off. Now what this 8
implication of this is, is that it's not technology 9
neutral it's specific to what we know with respect to 10 existing designs that have a valve type feature to do 11 filling of the material.
12 If we were to look at something different 13 that's where we would perhaps look at 71.55©. And if 14 you look at and do a comparison between Golf and 15 Charlie, I think the way that 71.55(g) has evolved is 16 very much in the spirit of 71.55© which is looking for 17 a special design feature. That's the language in 18 71.55©.
19 CHAIR KIRCHNER: Okay. Typically, is that 20 Like a cap on an acetylene bottle or a hydrogen 21 bottle?
22 MR. PIOTTER: I would envision that that's 23 what that would look Like.
24 CHAIR KIRCHNER: A guard cap over 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
30 valve mechanism.
1 MR. PIOTTER: Yes, I believe that there 2
had been some historical cases, and I know that in 3
Europe, I do believe, that that's a requirement for 4
their cylinders, that they have an additional valve 5
protection in place.
6 CHAIR KIRCHNER: Thank you.
7 MR. PIOTTER: Yes, sir.
8 (Pause.)
9 MR. PIOTTER: If there is nothing further 10 I'll turn the next slide to Elijah.
11 MR. DICKSON: Good morning. This is 12 Elijah Dickson. I'm looking forward to being here 13 today to effectively recap several presentations we've 14 had over the last year and a half, I supposed, on our 15 Vogtle 2, the design control criteria GDC-19 and 10 16 CFR 50.67.
17 Just to recap some of these presentations.
18 The thought process in approaching this rulemaking was 19 to focus on, not only addressing some of the technical 20 bases with the rule itself, but with updating the 21 alternative source term to increase the applicability 22 of its use for these operational targets, as well as 23 updating several of the transport models that are, 24 contained in guidance.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
31 In recapping our presentations that we had 1
in regards to the control room design criteria itself, 2
we focused in three specific areas. The first, we had 3
discussed the foundation of the Commission's policy 4
and regulations concerning the radiation protection 5
framework. Within this framework we are able to 6
assess how the propose to amend the control room 7
design criteria would be possible.
8 And second we discussed, to provide a 9
general understanding of how this proposal fits within 10 the Commission's framework and then reviewing 11 evidence-based justifications based off of various 12 national and international organizations responsible 13 for radiation protection recommendations which have 14 strong scientific and technical underpinnings.
15 And then lastly, with these two areas 16 discussed we were able to proceed with developing and 17 presenting some reasonable regulatory relief by 18 proposing a modest increase in the control room design 19 criteria from 5 rem to 10 rem with the flexibility of 20 leveraging facility specific risk insights if a 21 conditional margin is needed above 10 rem when 22 performing a radiological consequence analysis. With 23 that, I can take some questions.
24 MEMBER DIMITRIJEVIC: Hi. This is Vesna 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
32 Dimitrijevic. So we had the previous discussion about 1
this applicability of the, you know, using the CDF as 2
the ranking measures and we have the comments that 3
things are maybe not connected.
4 But since our last meeting I actually went 5
and read your white paper and looked at everything.
6 And I took the serious thinking about this. And my 7
conclusion in this moment is that this is, using CDF 8
in this matter is not really in the spirit of risk-9 informed process because risk-informed means what it 10 says. It's risk informed. But here we just use the 11 general risk manager and, you know, try to define the 12 ranges based on this.
13 The risk-informed actually looks in that 14 if you were going to make a change what would be fewer 15 impacting. And what type of the change is occurring.
16 So here there is not that connection. That, what does 17 it change in, you know, control room, the dose, which 18 risk is impacted on this.
19 So there was not any attempt to define the 20 risk because you could try to define is this risk to 21 operator or is the risk to general public. And if 22 it's a risk to general public then the higher dose 23 towards that, because you want operators to stay long 24 to take care about, you know, the business or managing 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
33 an accident progression.
1 So basically this would be equivalent if 2
we say, okay, if you have a low CDF go and change 3
inspection intervals or, you know, extend your EPZ or, 4
you know, do flexible tech specs. That's not how it 5
works, it has to be related, the measures have to be 6
related to the risk.
7 So this is my opinion in this moment. If 8
you know, if we have Reg Guide 1.174 maybe actually 9
CDF, total CDF and LERF play a role on the, and 10 allowing you to make changes where you have to define 11 the changes in the risk.
12 But after reading your white paper I think 13 it made a really good case when it comes to the 14 performance base and therefore I don't see really need 15 for this four, you know, ten percent to 25 percent.
16 I think that this paper printed will allow 25 percent 17 as an alternative without, you know, considering 18 really CDF because CDF has nothing to do with that.
19 And actually, the case could remain, the 25 percent is 20 supporting CDF by allowing operators to be, you know, 21 involved in managing accidents longer.
22 So, so my main comment there is that 23 really using the CDF is the general, is such a 24 general, is not in the spirit of risk-informed 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
34 application. That's not what risk-informed means.
1 It's not informed on any risk. CDF is the general 2
risk manager, you know, for a lot of things Like that.
3 But how do we connect that to the control room dose, 4
it's not really defined.
5 However, I think your white paper will 6
support claiming the 25, using just 25 percent as 7
alternative risk-informed. So, that's my comment on 8
this.
9 CHAIR KIRCHNER: Thank you, Vesna. And if 10 I might join in, Elijah, thank you for the background 11 papers those were very informative.
12 Again, you're hearing individual member 13 opinions. We'll get together and deliberate later, 14 but from my perspective I thought you laid out enough, 15 and it's up in front of us, I think to justify the 10 16 rem as the revised control room design criterion and 17 25 rem under special circumstances. So, you have a 18 different phrase so I probably didn't get that right.
19 And there's a lot of literature that you 20 site that provides ample justification for the two 21 numbers. I had a similar problem as Vesna, I suspect.
22 And I'll take it in a different way.
23 If you look at what we're doing in 10 CFR 24 50, 52 and 53, we are using the same dose criteria as 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
35 in Like 50.34 or 52.47. And I don't remember where it 1
is in 53. And then the, let's think about advance 2
reactors because they're going to come in and see this 3
and want to use this as well for their control room 4
design.
5 Typically what we've seen, so you had a 6
fix dose that was acceptable to the public or to the 7
operators and then if you have a plant that has a 8
better CDF, for example, you probably also can make 9
arguments on the lines that maybe the source term is 10 less as well. And you take advantage of that by not 11 changing the dose allowed, but for example, in one 12 application that we reviewed, you've probably involved 13 in this, we see them pulling in the EPZ versus the ten 14 mile but the dose is still the same. So the EAB and 15 the LTZ, they still have to make, meet the same 16 criterion.
17 So I'm a little concerned as to one, what 18 the public would make of this if we had a sliding 19 scale of acceptable dose to our operators rather than, 20 this is it, and design to that. And we talk amongst 21 ourselves about this being a design objective not a 22 target in terms of exposure. But that's subtly. I 23 don't know how you convey that to the public well.
24 And so, my thinking is, if you set 10 and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
36 25 as the limits then it's up to the applicant to 1
demonstrate to you that they are within these design 2
objectives. And there are lots of ways they can do 3
that.
4 But it seems to me sharpening the pencil 5
on the, even though currently we have mature PRAs that 6
we have reasonable confidence in, we've got a lot of 7
PRAs now, we've got a lot of operational data to back 8
them up, we have a lot of equipment reliability data 9
to back them up. We're not going to see that advance 10 reactor applications.
11 So the uncertainty bands that we're going 12 to see, certainly with advance reactor PRAs, in my 13 estimation, are going to be much broader than what our 14 confidence is in the current fleet. So I'm just 15 concerned, one, the optics to the public having the 16 sliding scale of "acceptable dose," that's not what we 17 intend but it's the design objective.
18 And then banking that on a estimate of 19 CDF. Here I align with Vesna, I think LERF is 20 probably more relevant to the question at hand. But 21 then I also think through, I'm trying to think 22 through, what will the operating plants do, will they 23 sharpen their pencils or will they actually go and 24 redesign the control room to provide more shielding, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
37 better filter, better ventilation, whatever their 1
options are. They're not going to move the control 2
rooms they're fixed sites now and so on.
3 So I get, from your perspective of 4
incentivizing better performance through the use of 5
the risk metrics, but I think from a practical 6
pragmatic standpoint I don't think it works. But 7
that's just one members opinion.
8 I think it's going to be very difficult to 9
convince the public that there should be a sliding 10 scale on acceptable dose because they're going to read 11 it Like, oh, okay, the operators could have a higher 12 dose because they have a lower CDF. But that is a, in 13 my estimation, a tough, a tough sales job.
14 But you have provided ample justification 15 for just going with the 10 and 25 as you have on the 16 slide before us. So I'll stop there. And again, 17 that's not the Chair's opinion that's one Member's 18 opinion.
19 MEMBER BIER: Yes, this is Vicki Bier.
20 Following up on that. I think there is potentially a 21 rationale for doing that that may the level of 22 protection that we owe the operators is lower if the 23 chance of every encountering such a situation is 24 extremely small. But that also wasn't really 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
38 articulated in the document.
1 There may have been a lot of thought 2
process that went into that determination, but if you 3
do want to take that perspective I think, you know, I 4
would agree with Walt, you need to think about how its 5
conveyed and, you know, how to justify why that's 6
reasonable. I thought about it a fair bit and 7
couldn't decide for myself which way I Like better, 8
but --
9 VICE CHAIR HALNON: This is Greg. I can 10 talk from a non-practitioner, more from an operations 11 perspective, and it means nothing to me from the 12 standpoint of, when I enter the control room in the 13 morning whether or not you tell me the design of the 14 control room is 10 or 25 rem. I know that my 15 occupational limits apply. I know that my emergency 16 plan states what I can and can't get. I know that 17 I'll be relieved at a time based on what's happening, 18 and I know that this is the design space.
19 Now, from a member of public, if you 20 understand the difference between CDF and LERF you 21 probably could understand the difference between 22 design criteria and dose, occupational dose. And in 23 fact, the only time this probably will be used in the 24 operating fleet is when you need a AUD or some other 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
39 type of relief from a regulatory problem based on 1
text, charcoal, HEPA test or whatever the case may be 2
that your design is efficient and you have increased 3
leakage or lacks efficiency or whatever the case may 4
be, you would probably use it for a short period of 5
time and do a calculation to justify something.
6 Now, to the newer sites, the advance 7
reactors, we're talking much lower CDFs, if it even 8
applies, given the length of fuel. You may be seeing, 9
so maybe LERF may be more appropriate for some of the 10 reactor types. But the bottom line is, from a 11 layman's perspective, if you give me a safe plant I 12 have less of an opportunity or less of a probability 13 of having reactions that could cause the problem, I'm 14 going to feel more comfortable with a looser design 15 based on that.
16 And so I'll just give you that. It works 17 for me because operating this you got safe plant, 18 you're going to tell me that now it's, and I know it's 19 a terrible word, but it's safer, better, less 20 probability, less risk, and I'm going to feel more 21 comfortable with it. So again, from the layman's 22 perspective, on my side it works fine for both 23 existing and the advance reactors.
24 MEMBER ROBERTS: This is Tom. Following 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
40 up on all of that, I think the key on what Vesna's 1
point is, is the severe accident risk. And does this 2
change to the design criteria, change the severe 3
action of risk. And I think those are two separate 4
questions. That if you were to have a five times 5
leaker control room because your design criteria went 6
up by a factor of five, and maybe you are affected to 7
severe action of risk and now need to be evaluated.
8 It's also important to note that the reg 9
guide revision is still going to require assessing any 10 design change that's consequence, potential 11 consequence with severe accident performance. So 12 maintain that as part of the guidance requires the 13 applicant to consider whether or not what they're 14 doing would effect severe accident risk. I think its 15 important to keep in mind those are two different 16 questions that both need to be addressed.
17 So I don't know if that helps out with 18 Vesna's concern but I think it is important that any 19 design changed enabled by this rule change would 20 require great assessment for the PRA parameters of, is 21 it effective severe accident risk.
22 CHAIR KIRCHNER: Well we get into this 23 problem by assuming a maximum hypothetical accident 24 and a source term with it. So that's --
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
41 MEMBER ROBERTS: And that MHA is not, 1
really the maximum hypothetical because it makes an 2
assumption as part of the design criteria. And so a 3
severe accident could significantly exceed those 4
doses. So that's part of what a severe accident 5
assessment or a PRA is supposed to look at.
6 CONSULTANT SCHULTZ: Elijah, this is Steve 7
Schultz. I think what you've done in your paper, in 8
both papers obviously, clearly, the discussions and 9
the evaluation of the appropriate dose criteria that 10 could be used, and are used, internationally and now 11 nationally with this, this improvement, both of them 12 are excellent pieces of work. And so the question 13 that, bringing up here is the metric of CDF as it 14 applies to the application of extending the dose 15 beyond 10 rem TEDE.
16 I think this is an area where, I don't 17 know exactly how you presented going forward in the 18 draft rule going to a final rule, but it is an area 19 where further discussions with Industry would be very 20 helpful because the metric associated with the 21 evaluation, and then plant safety and its effect, if 22 you will, on operators. The operators have a lot of 23 opportunity to control accidents and to prevent severe 24 accidents and so forth. We've seen that.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
42 The plants have made a lot of improvements 1
associated with preventing accidents, and of course, 2
severe accidents. Thinking of Davis-Besse, thinking 3
of Fukushima and lessons learned that Industry and the 4
NRC have really addressed in the last 20 years.
5 So I think there are some opportunities 6
here for further discussions trying to pinpoint how 7
one could move forward with a
risk-informed 8
performance-based approach. Maybe twists some metrics 9
that are used to move forward if in fact that 10 incentive is needed to determine the need for a larger 11 control room dose as part of the design.
12 As Walter said, you have the design 13 approach with regard to the control room and then you 14 have the allowance and ability for the operator to 15 stay in the control room, do work that's associated 16 with severe accident prevention or response. So, just 17 a comment.
18 Excellent work has been done as Theresa 19 had said at the beginning. The Staff has done 20 excellent work in these areas and really should be 21 congratulated. And I hope the Commission sees that 22 and recommends that you move forward with this piece 23 of it and the overall rule application. I'm expecting 24 that's going to happen.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
43 MEMBER DIMITRIJEVIC: My point in this 1
discussion was a little bit more general in terms of 2
the risk matrix. It's not that risk matrix is at risk 3
which is impacted by this. So by using CDF we want to 4
say does a TEDE impact CDF? Does it make any change 5
in CDF?
6 We don't really have that connection. So 7
we are using a general, you know, CDF and LERF, which 8
are the prime hazards, and it's calculated to connect 9
it to something where we don't see the connection. So 10 it's not the risk-informed. To be risk-informed it 11 has to be the right risk.
12 As I said, we have many risk-informed 13 applications who eventually working in Industry. So 14 None of them says, as I said before, if you have 15 allowed CDF, go ahead and use that, you know, the 16 flexible tech specs. No, it says, check out how does 17 these tech, specific tech specs impact your CDF. It 18 doesn't say, A, if you have a low CDF go ahead and 19 take your diesel generators out for two weeks. You 20 have to calculate risk associated with that.
21 So that's my sort of objective that this 22 is not in the spirit of risk-informed application.
23 However, if you can make a case, the 25 rem, it will 24 allow the operators to have an accident in the longer 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
44 time. That would be some risk argument, so.
1 CONSULTANT SCHULTZ: I agree with your 2
point Vesna, especially the latter. The last one 3
you've made. This is Steve.
4 CHAIR KIRCHNER: So Elijah. Do you have 5
more slides?
6 MR. DICKSON: I think that's all I had.
7 CHAIR KIRCHNER: Okay. Thank you.
8 MR. DICKSON: Other than questions. Yes.
9 CHAIR KIRCHNER: Yes. We thank you.
10 MR. DICKSON: Yes.
11 MR. MESSINA: Hi. So I'm Joe Messina from 12 the Nuclear Methods and Fuel Analysis Branch of NRR 13 and I'm going to talk about how we're addressing FFRD 14 with 10 CFR 50.46(a).
15 Next slide please. So in this rulemaking 16 we are, we are proposing a voluntary alternative to 17 50.46 to re-categorize large break LOCAs as beyond 18 design basis accident. Specifically LOCAs above a 19 transition break size as beyond design basis accident.
20 The smaller breaks would be treated as they currently 21 are under 50.46 requiring high probability, which has 22 been interpreted at 95-95 to date. And breaks above 23 the transition break size would be, allowed to be 24 relaxed. So they could use best estimate modeling an 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
45 more realistic assumptions based on their lower 1
likelihood of occurrence.
2 And we leveraged a lot of what was done in 3
the 10 CFR 50.46(a) rulemaking in the early 2000s 4
which went to the Commission as a direct final rule in 5
2010 but was ultimately rescinded after Fukushima.
6 Next slide please. So how does this 7
address fuel dispersal? So we think it, we believe it 8
addresses fuel dispersal in its coolability. So while 9
it, we don't have significantly different words in the 10 rule language on coolability we clarify in the 11 preamble or statements of consideration that 12 coolability is not necessarily in conflict with 13 dispersal. Some amount of dispersed fuel can be shown 14 to possibly remain coolable and safe during a LOCA so 15 therefore it could be acceptable to have a predicted 16 occurrence.
17 And we expect that true best estimate 18 modeling and realistic assumptions would significantly 19 reduce or even eliminate the calculated potential for 20 fuel dispersal. But if fuel dispersal does occur 21 there is some high level guidance on analyzing the 22 consequences of fuel dispersal in DG-1434.
23 And while this approach does not 24 physically address potentially non-mechanistic 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
46 approaches to evaluating FFRD, such as those described 1
in other alternatives in the regulatory basis, such as 2
Alternative 4 or modified Alternative 5. Although 3
licensing pathways exist, such as the topical report 4
process, and we anticipate that the performance-based 5
criteria in the rule would facilitate these, an avenue 6
for these alternatives in the future.
7 Next slide please. So I want to highlight 8
some of the changes that we made since the January 9
Subcommittee meeting. There are three ones, three 10 changes on this slide.
11 And so, originally we discussed how there 12 is a requirement in 50.46(a), the rule language to 13 inspect ten percent of similar metal welds on piping 14 larger than the traditional break size. Based on the 15 discussions in the Subcommittee we have replaced the 16 requirement for ten percent of similar metal welds to 17 an approved, NRC approved sampling of similar metal 18 welds. And we've made corresponding changes in the 19 DG-1428 on plant specific applicability of the 20 transition break size.
21 Additionally, in the definition of 22 transition break size we added that green underlined 23 text there that allows for a plant specific 24 alternative break area to be, to adjust it. So 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
47 licensees, current operating plants, if something 1
causes them not to agree with our transition break 2
size, or we believe that their transition break size 3
should be a larger, they can propose their own plant 4
specific transition break size.
5 And then we also added a little bit of 6
clarification on alternative approaches in the 7
preamble and SECY paper on kind of what I discussed 8
previously. That the performance-based view of 9
coolability, and the fact that fuel dispersal is not 10 necessarily incompatible with coolability can 11 facilitate alternative approaches such as those 12 suggested in Alternatives 4 and 5. And we would plan 13 to have further interactions with Industry on other 14 potential alternatives via interactions such as 15 workshops.
16 Next slide please. So I wanted to provide 17 a relatively high-level overview of the requirements 18 of 50.46(a). So I mentioned the weld inspections. On 19 similar metal welds above the transition break size.
20 They would have to demonstrate plant 21 specific applicability of the transition break size, 22 make sure that any changes made do not invalidate the 23 transition break size. They should have a risk-24 informed evaluation process to analyze changes enabled 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
48 by 50.46(a). And the criteria for that would be that 1
changes must be kept to a very small risk increases.
2 So those CDF and LERF metrics are on this screen. And 3
that the overall risk must remain small.
4 Establishes two principle ECCS performance 5
criteria maintaining fuel coolability and long-term 6
cooling. And then as four, fuel performance criteria, 7
addressing cladding degradation phenomena, maintaining 8
fuel coolability, avoiding explosive concentration of 9
combustible gas and long-term core.
10 And then these last two bullets talk about 11 the differentiation in the breaks. So break, 12 transition break size would still require high 13 probability that the criteria are met, just as they 14 are today. And then breaks above the transition break 15 size must be met to at least a best estimate level.
16 Next slide please. I created this graphic 17 to potentially help see how some of the rule language 18 maps into the guidance. So you'll see that we have a 19 DG on plant specific applicability of the transition 20 break size which help to address those few things in 21 the rule on the left. DG-1426 establishes criterion 22 guidance for the risk-informed evaluation process.
23 And then for the fuel performance criteria 24 we have these four DGs. The first three, DG-1261 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
49 through 1263, were from 50.46(a), 50.46© rulemaking in 1
2016 that we've updated a bit. And then the last one 2
I had mentioned before was DG-1434, addressing the 3
consequences of fuel dispersal.
4 Next slide please. So I wanted to have a 5
few, I have a few extra slides on some of the topics 6
that we dove completely into in the December and 7
January subcommittee meetings. I'll go quickly 8
through them, but one of the major topics was the 9
transition break size and how it was developed.
10 So, in the originally 50.46(a) rule there 11 was a lot of work done to establish LOCA break 12 frequencies in NUREG-1829. And then they also 13 addressed seismic risk in NUREG-1903. And these were 14 used to develop a transition break size which was, 15 which was established based on the frequencies, as 16 well as other considerations such as uncertainty, as 17 well as making sure that there are just regulatory 18 stability.
19 And then in this current rulemaking effort 20 we've done work to reconfirm it since that work was 21 done basically 20 years ago. So we've reconfirmed 22 NUREG-1829 with a number of studies. We did internal, 23 external elicitations. We've looked at recent 24 operational experience. We've done some XLPR 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
50 probabilistic fraction mechanics calculations. And 1
we've looked at international operational experience 2
in the database.
3 We've also reconfirmed NUREG-1903 by 4
evaluating flawed piping failure, indirect piping 5
failure and component piping failure. So there was 6
work done, but for the flawed and indirect failures it 7
was established that more plant specific analysis 8
would be needed to confirm. But for the unflawed 9
failure we found that failure probability was 10 significantly low compared to the one times ten to the 11 negative fifth review frequency used as the basis to 12 establish a transition break size.
13 Now, overall with this we were able to 14 confirm that the transition break size was applicable 15 as long as a plant specific applicability issue.
16 Next slide please.
17 CHAIR KIRCHNER: Joe, before you go on.
18 On the 1903 confirmation, so what I understand the 19 Industry feedback that you've had so far, and what 20 we've heard, one of the issues they're having is the 21 need I think to go back and do a rather complete re-22 analysis from the seismic standpoint of their NSSS 23 systems. Where do you see this playing out when you 24 implement the proposed rule? How much can they fall 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
51 back on the post-Fukushima analysis to address the 1
seismic aspect because specifically one of those sub-2 bullets there under the 1903 confirmation?
3 MR. MESSINA: Yeah, I'll point to Dave 4
Rudland. Staff.
5 MR. RUDLAND: Hi, I'm Dave Rudland from 6
the Staff. Yeah, the confirmatory work that we did 7
took the most recent seismic hazard curves after the 8
Fukushima accident developed and confirmed that the 9
results that we had in the original 1903 were still 10 valid. And in the analysis, but the analysis that we 11 did was not bounded for the fleet and so that's why 12 the plant-specific applicability is needed.
13 And what we did was he leveraged, plants 14 are able to leverage these inspections that Joe talked 15 about to eliminate -
16 MR. MESSINA: Right.
17 MR.
RUDLAND:
those particular 18 analyses.
19 CHAIR KIRCHNER: Okay. It's hard for us 20 to sort out hearing both sides of this. It sounds 21
- Like, from the Industry perspective, it's a
22 considerable burden.
23 MR. RUDLAND: Again, if they do the 24 inspections there is no additional analysis needed.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
52 And if they don't do the, after the inspections are 1
part of the requirements of approval.
2 CHAIR KIRCHNER: Right.
3 MR. RUDLAND: They can just leverage those 4
as long as they, the critical welds that they're 5
analyzing are in the inspection curve. Okay?
6 CHAIR KIRCHNER: Go ahead, Joe.
7 MR. MESSINA: Thanks. Next slide please.
8 So there was a bunch of discussion on the clad 9
testing, DG. So DG-1261 through 1263 in the previous 10 Subcommittee meetings. DG-1261 addresses breakaway 11 oxidation and how experimental, experiments could be 12 done to address this and how initial testing and 13 periodic confirmatory testing should be performed.
14 DG-1262 defines experimental technique for determining 15 post-quench ductility, establishing ductility 16 transition for zirconium-alloy material.
17 And then DG-1263 establishes limits to 18 address zirconium-alloy cladding degradation 19 phenomena. So it establishes post-quench ductility 20 and breakaway oxidation as well as has a PCT limit and 21 a limit on the metal combustible gas. It also 22 provides cladding hydrogen uptick models as well as 23 providing guidance to consider the impacts of oxygen 24 diffusion from the inner surfaces of the cladding.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
53 Next slide please.
1 CHAIR KIRCHNER: Before you go on. The 2
breakaway oxidation seems, that seems to generate some 3
feedback.
4 MR. MESSINA: Yes.
5 CHAIR KIRCHNER: Okay. So what is an 6
effective way to look at this problem? For the 7
current, I shouldn't say current. What would be, you 8
know, for recent reloads using advance claddings at 9
different types this doesn't seem to be an issue. Is 10 there a way that, from the advance cladding materials 11 that you've already reviewed that this one could be 12 cast aside, so to speak, based on experience with some 13 of the more recent cladding types that, I'm trying to 14 stay out of proprietary nomenclature on all the rest 15 so I'm not doing well.
16 But, you know, recent zircaloy clads don't 17 exhibit this behavior. Is there a way that you can 18 determine that in advance so to speak by demonstrated 19 performance to date, existing manufacturing processes?
20 MR. MESSINA: So I think the challenge 21 lies in that, you know, small changes in allow 22 composition, manufacturing processes could be to 23 breakaway, unexpected breakaway oxidation. So, but 24 I'll point to James Corson who wrote the DG.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
54 MR. CORSON: Yes, James Corson from the 1
Staff in the Office of Research. So the first thing 2
I'll say is that all cladding alloys will exhibit some 3
breakaway oxidation behavior eventually. But it's not 4
going to be as severe as what we saw with Like U-110.
5 When we look at the more modern alloys, 6
breakaway times are 3,000, 4,000, 5,000 seconds. And 7
it's not Like the flaking off the oxide, the really 8
bad visual behavior that you see, but it is 9
characterized by a increase in the oxidation rate and 10 an increase in the hydrogen pickup rate. So 11 eventually cladding alloys will reach a breakaway 12 oxidation time.
13 I think a lot of the consideration is, how 14 much, or if any, periodic testing is required. And 15 so, way back in 50.46©, early days, we had pretty 16 strict requirements for testing frequency. They were 17 relaxed a little bit in the final rule, draft final 18 rule, 50.46©. We removed the testing requirements 19 from the rule language here but the guide of course 20 still talks about periodic testing.
21 So I think that's where a lot of the 22 consternation lies. And that's something we will take 23 a look at going forward. But I do think there needs 24 to be some sort of limit and for a completely new 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
55 allow, at least some initial testing to verify that 1
your breakaway time is 4,000, 5,000 seconds and not a 2
hundred seconds or so Like we saw with U-110. So I 3
hope that helps.
4 CHAIR KIRCHNER: Thank you. Go ahead, 5
Joe.
6 MR. MESSINA: Next slide please. And this 7
is my last slide. So there was a lot of discussion of 8
what do we mean by best estimate or true best estimate 9
as I used throughout the FRN a bit to distinguish from 10 the traditional best estimate plus uncertainty towards 11 the example that's described in Reg Guide 1.157.
12 So we, there is a lot of discussion on 13 this. We meant to be consistent with what is 14 permitted in other beyond design basis accidents, such 15 as ATWS and station blackout. And, you know, we 16 stated phenomenal inputs without consideration of 17 conservative biases and adding all these 18 uncertainties.
19 But we still acknowledge that there is 20 some ambiguity to what this means, so we would plan to 21 work with Industry on clarifying a definition of best 22 estimate that we can both live with. And potentially, 23 if a guidance document is needed, we could consider 24 doing that too.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
56 CONSULTANT SCHULTZ: Joe, this is Steve 1
Schultz. In the definition of true best estimate, 2
again, going back to what the NRC and the Industry, 3
both separately and together did in response to 4
Fukushima, which was a considerable effort in terms of 5
equipment, of access, availability, development, 6
operator training, response to mitigate severe 7
accidents and stuff, is there an opportunity to 8
include that in the true best estimate evaluation?
9 The equipment that's available for the operators to 10 mitigate any accident.
11 I understand to keep in line with ATWS and 12 SBO, bit those are different accidents than other --
13 MR. MESSINA: Yes.
14 CONSULTANT SCHULTZ: -- severe accidents.
15 More time might be available.
16 I'm also think that both Industry and the 17 Staff would be interested in looking at, once one 18 defines true best estimate, what is the result, not 19 only for the large-break but also for small-break 20 LOCA?
21 I understand that there's differences in 22 likelihood of the event and so forth, but what is the 23 result if one first defines what true best estimate is 24 and then applies it across the board to small-break 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
57 LOCA, and perhaps even other accidents? I think it 1
will be very useful to gain that appreciation.
2 MR. MESSINA: Yes, good point. Thank you.
3 And I do believe they would be able to leverage some 4
of the stuff done post-Fukushima. For example, 5
operator actions would be able to be credited, and 6
non-safety related equipment would be able to be 7
credited for these LOCAs.
8 CONSULTANT SCHULTZ: Good. Thank you.
9 Again, excellent work has been done in this area. I 10 really encourage you to continue.
11 MR. MESSINA: Thank you.
12 MEMBER MARTIN: This is Bob Martin. Of 13 course we talked about this during the Subcommittee 14 and I can't help myself but to reiterate, there is 15 plenty of historical precedent even in severe 16 accidents, SECY-90-16, SECy-93-87, as they related to 17 advance light water reactors and severe accidents.
18 There is statements in effect of how uncertainties 19 must be addressed.
20 The uncertainties particular for such 21 events, and now we're going to call large-break LOCA, 22 you know, beyond design basis. There is no, you know, 23 no exception to that one either.
24 Crediting certain non-safety equipment, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
58 you know, to the extent where you put evaluated the 1
uncertainties. Maybe some of the, you know, the true 2
risks. You know, that's certainly a plausible type 3
strategy.
4 But, you know, where I'm bothered by is 5
the word true. I mean, and that just leads to a lot 6
of different interpretations. But whether we're 7
talking 95-95 or 90-95 or something Like that, I mean, 8
that is still somewhat debatable. But the language in 9
the regulation is still something along the lines of, 10 you know, high probability of protection or something 11 Like that. And that should definitely remain.
12 (Laughter.)
13 VICE CHAIR HALNON: Joe, this is Greg.
14 Several times we've mentioned the TRE review of the 15 ALS. Are you able to share a status of where you're 16 at with that and whether or not you see a path forward 17 to that and is that going well?
18 MR. MESSINA: I'll point this over to my 19 management.
20 (Laughter.)
21 MR. KREPEL: Hi. This is Scott Krepel, 22 through a sign language interpreter, the Branch Chief 23 of the Nuclear Methods and Fuel Analysis Branch.
24 I will say that basically there are four 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
59 different topical reports that we are working through, 1
and we can draw up them if there's time. We did 2
finish an audit on two of them, and so far it does 3
seem Like things have been going pretty well, but I 4
don't know what the result is yet, so we will be 5
finding out at the end of the year. Stay tuned.
6 VICE CHAIR HALNON: So the end of the year 7
of 2025 is when you expect to give the next status I 8
take it?
9 MR. KREPEL: Roughly, yes. That is 10 roughly the time frame that we do expect to have the 11 safety evaluation written up.
12 (Simultaneous speaking.)
13 VICE CHAIR HALNON: Thank you.
14 MR. KREPEL: Yeah. So just checking with 15 Dave Rudland there. So, yes, we haven't identified 16 any roadblocks as of yet.
17 VICE CHAIR HALNON: Thank you.
18 MEMBER BALLINGER: This is Ron Ballinger 19 then. Given the time scale for this analysis is that 20 in time to effect this rulemaking?
21 MR. MESSINA: To effect the rulemaking?
22 MEMBER BALLINGER: Well, wrong word.
23 (Simultaneous speaking.)
24 MR. MESSINA: Well, we're not exactly 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
60 incorporating that into the rule, so --
1 MEMBER BALLINGER: Yeah.
2 MR. MESSINA: But Did Scott want to -
3 MS. CLARK: Theresa wanted to.
4 MR. MESSINA: Oh, sorry.
5 MS. CLARK: So this is along the lines of 6
what Joe was saying in his slides about other things 7
that are going on in parallel that are facilitated by 8
the rulemaking.
9 So one of the things that we want to 10 explore when we put this out for public comment is to 11 make sure that nothing in the rule impedes these 12 alternative approaches.
13 You
- know, we have these different 14 performance-based requirements that we think would fit 15 really well with some of these other alternative 16 approaches, but we haven't yet found it necessary to 17 implement the rule in order to address these 18 alternative approaches.
19 So Like we're reviewing ALS right now 20 under the current regulations. It might be 21 facilitated and perhaps easier to document when a 22 safety evaluation of the regulation is completed with 23 these performance-based requirements, but that's going 24 on now under the currently regulatory structure.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
61 So we don't really want to disrupt that 1
ongoing process and, similarly, we intend to be 2
talking about Alternative 4, which, again, could be 3
facilitated by the requirements, but we plan to talk 4
about that outside of the rulemaking process.
5 So it's sort of -- If we find out through 6
public comment that there needs to be adjustments to 7
the rule to help with these other things, if there is 8
insights from these ongoing parallel efforts that we 9
want to roll into the rule, of course we would think 10 about that, but right now they are going down parallel 11 tracks.
12 We don't think they interfere with each 13 other but we're trying to keep our ears open for any 14 intimate interference.
15 VICE CHAIR HALNON: Okay. Thank you.
16 MR. MESSINA: Next slide. And that's all 17 I have.
18 CONSULTANT SCHULTZ: Do you want more 19 questions?
20 (Laughter.)
21 CHAIR KIRCHNER: Joe, have you and your 22 colleagues thought through applicant comes in with a 23 "best estimate," but let's assume that definition is 24 worked out to both parties understand what 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
62 boundaries are on best estimate, and you have fuel 1
dispersal?
2 None of the codes that I am familiar with 3
really can handle that phenomenon well. You are not 4
going to have an experimental dataset to benchmark 5
them against. That would be extraordinarily costly 6
and take many years.
7 So how do you avoid once you get into the 8
dispersal
- regime, significant dispersal, large 9
amounts, and that is the next question, obviously, 10 what defines large amount of, what is an acceptable 11 amount of fuel dispersal? It's a different way to 12 think of it.
13 The codes -- Maybe I'll turn to my 14 colleague Scott and ask to be proven wrong, but I 15 cannot think of a code that would pass muster for an 16 evaluation method for LOCA that really can handle that 17 kind of phenomena that's currently accepted by the 18 Staff.
19 So what happens when someone comes in and 20 tries to gather an argument, well, this much fuel 21 dispersal is acceptable and I think I know it's, maybe 22 it's in the bottom of the vessel, but maybe it's in 23 the ECCS system by being, or maybe it's out in the 24 containment somewhere, how do you bound this kind of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
63 problem once you go over that threshold with 1
significant fuel dispersal?
2 How would you see that playing out between 3
yourselves and an applicant?
4 MR. MESSINA: I think based on the current 5
state of knowledge most Industry would probably elect 6
to go with a note first criterion for fuel rods 7
susceptible to FFRD and maybe they continue to do 8
experimental research to try and improve their codes 9
to analyze this.
10 We are working with the Office of Research 11 to try and get a better idea of what amount could be 12 acceptable with our current state of knowledge and 13 current codes. That work is ongoing.
14 The PIRT that we, the PIRT panel that we 15 sponsored, they believed that bounding, that the 16 current methods could be used to perform bounding 17 calculations of fuel dispersal.
18 So it's possible that they could do 19 something, bound to current scenarios, maybe, you 20 know, bounding blockage of the grids or whatnot, so --
21 MEMBER BALLINGER:
But without 22 confirmatory experimental work, that's a tough one, a 23 very tough one.
24 CHAIR KIRCHNER: I'm thinking of GSI-191.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
64 MEMBER BALLINGER: Yeah, that's what I was 1
going to say, what a nightmare that was.
2 CHAIR KIRCHNER: And the fact that, you 3
know, they're -- So not fuel, but you have debris and 4
then you're looking at blockage and such and you get 5
into, wow, it's a difficult space.
6 Really you find yourself with paralysis by 7
analysis, you know. If the applicant presents you 8
something, you go to research and research does their 9
analysis or, you know -- And I get the idea of trying 10 to bound it, but there is so much uncertainty in a 11 different sense than when we talk about evaluation 12 model codes uncertainty.
13 I mean the uncertainty - Once physical, 14 you know, once the physical structure is lost the 15 uncertainty space just -- And complexity is a better 16
- word, actually.
The space complexity grows 17 exponentially and the uncertainty on all that is very, 18 very large.
19 So how do we see the Agency dealing with 20 this if someone says, well, it's okay to have, I'll 21 pick a number, 10 percent of the fuel dispersed 22 throughout the system somewhere but we don't know 23 where it is.
24 Coolability I think, as we talked about I 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
65 think, you know, TMI demonstrated coolability, so 1
that's not an issue but where is it and et cetera. So 2
any thoughts?
3 You gave a good answer, obviously, if it's 4
a no burst type of criterion as the figure narrative 5
then life is exponentially easier.
6 MR. MESSINA: Yeah. We are continuing to 7
look into it. I don't think I can say much more. We 8
don't really want to end up in that analysis paralysis 9
spot, which is part of the reason why we pursued this 10 rulemaking in the first place -
11 CHAIR KIRCHNER: All right.
12 MR. MESSINA: -- because we thought, you 13 know, with the current rule and high probability it 14 would just be probably inconceivable in the next, 15 yeah, five years for anyone to do anything with high 16 burn-up. So that's part of the reason, yeah.
17 CHAIR KIRCHNER: Sure, yeah. No, the 18 motivations are clear to move forward, but some of the 19 problems that might ensue may prove intractable in the 20 regulatory process.
21 (Simultaneous speaking.)
22 CHAIR KIRCHNER: Go ahead, Scott.
23 MEMBER PALMTAG: This is Scott Palmtag.
24 I agree with you completely, Walt. Some of the things 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
66 I brought up before, other things I've heard, everyone 1
is kind of focused on coolability, but you might want 2
to think about unintended consequences, right, we 3
have.
4 Coolability is important, of course, to 5
keep in mind, but if you have this dispersed to your 6
fuel, I'm just thinking of the cleanup processes, the 7
doses, where would this go, is it stuck in the steam 8
generators, and just huge safety implications.
9 Don't limit yourself just to the 10 coolability. I think there is a lot of other things 11 and if you start thinking about all these other 12 situations, the doses, the cleaning this up, I would 13 personally recommend, you know, no burst criteria.
14 Then, also, historically we've got the 15 comments from the public. Ron, you know the name 16 better than I do, but, you know, the original peak 17 clad temperatures were based on a no burst criteria.
18 So I think historically by allowing burst 19 is a huge regulatory change and I'm personally against 20 that as well.
21 MR. MESSINA: Well I'll say in the current 22 regulatory framework we do allow burst. We needed 23 burst.
24 (Simultaneous speaking.)
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
67 MEMBER PALMTAG: Yes. I'm sorry, yeah, 1
dispersion I guess is the -
2 MR. MESSINA: Yes, dispersion.
3 MEMBER PALMTAG: -- better word. Thank 4
you.
5 MEMBER BALLINGER: But that's a -- This 6
issue has tentacles into other areas where you do 7
allow fuel failure, so you do really need to be 8
careful that at a high burn-up if we allow fuel 9
failure for a rod injection accident or something Like 10 that now we're still having to deal with dispersal.
11 MEMBER PETTI: Let me just say we still 12 have Industry. I mean some of us have a hard stop at 13 noon hand, so it would be good to try to get Industry 14 in before, but I haven't heard anything here that 15 isn't already touched in the letter -
16 MEMBER BALLINGER: Oh, yeah.
17 MEMBER PETTI: -- that diversifies this, 18 yeah, I think. It's just confirmation.
19 MEMBER BALLINGER: And we are dangerously 20 close -
21 (Simultaneous speaking.)
22 MEMBER BALLINGER: Well, we're not just 23 dangerously close, we're beyond.
24 CHAIR KIRCHNER: Well let's have 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
68 Industry presentation and we can over it.
1 MEMBER BALLINGER: Yeah, that's what I was 2
going to -
3 CHAIR KIRCHNER: We have flexibility in 4
our lunchtime maybe to start -
5 (Simultaneous speaking.)
6 CHAIR KIRCHNER: So let's hear from the 7
Industry first.
8 (Simultaneous speaking.)
9 CHAIR KIRCHNER: Thank you. The agenda 10 says 12:15, so --
11 MEMBER BALLINGER: Yeah, I would invite --
12 (Simultaneous speaking.)
13 MR. BURKHART: Chair, this is Larry 14 Burkhart from the ACRS Staff. If we need to go later 15 than noon in light of the other meetings that have to 16 take place is acceptable to start, to delay the start 17 of the afternoon session if we have to and just make 18 the appropriate announcement.
19 CHAIR KIRCHNER: Yeah.
20 MEMBER BALLINGER: Who is going to do it?
21 Oh, Al.
22 CHAIR KIRCHNER: Al is.
23 (Pause.)
24 MR. CSONTOS: We have lots of slides. 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
69 cover slide.
1 CHAIR KIRCHNER: Okay, go ahead, Al.
2 MR. CSONTOS: All right.
3 CHAIR KIRCHNER: The floor is yours.
4 MR. CSONTOS: Thank you. So, as you know, 5
we're really not going to deviate much from what we 6
presented back in the January meeting and, also, back 7
in the December meetings. Much of it is very similar.
8 Next slide. So you know this, we have 9
LERs coming in, both advanced fuels and power uprates.
10 Really the -- I just came from EPRI meetings this 11 week, the Nuclear Power Council Meetings, and we're 12 seeing more and more interest in uprates.
13 The schedule, again, to reiterate, it's 14 really, really vital to keep that. I was talking to 15 Member Schultz here, or Consultant Schultz now. You 16 know, what we have done in a lot of the workshops with 17 Reg Guide 1.183 and also just the dialogue that we've 18 had here has been what can we do in the time frame.
19 (Simultaneous speaking.)
20 CHAIR KIRCHNER: Hang on. We've got 21 someone -- Please if you are listening in mute your 22 microphone. Thank you. Go ahead, Al.
23 MR. CSONTOS: Okay. So a lot of what we 24 have done and a lot of the discussion, the dialogue 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
70 we've had with the Staff, has been what is achievable 1
within the time frames for the rulemaking.
2 So I know you've had a lot of discussion 3
about Elijah's, you know, the dose criteria and the 4
sliding scale. There are some things in there that we 5
were looking into what could be done in the future.
6 For example, looking at CDF and LERF and 7
looking at changes that we could make and crediting 8
operator actions, crediting -- A lot of things that 9
we've gained in knowledge space from Fukushima.
10 We knew we could not get there in this 11 time frame so we punted that to a future topical or 12 something along those lines. So that's where, you 13 know, we were working with the Staff to understand 14 what is achievable now versus what we have to think 15 about in the future, okay.
16 So everything we're talking about here was 17 with that mind set, okay. So, anyway, we think that 18 the draft rule has a lot of positives, okay, but we 19 also have our feedback.
20 You have these two letters we talked about 21 last time. They were -- They still remain relevant to 22 what our positions are and we really would Like for 23 you to go ahead and send this draft IE rule up to the 24 Commission for their review and not hold it up based 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
71 on some of the concerns that we're about to talk 1
about, okay.
2 We did have alignment with the Staff and 3
the management with workshops in the future to discuss 4
some of these areas of concern. What we would Like to 5
say is also there is this idea of the ADVANCE Act, you 6
know.
7 We really need this rule, proposed rule, 8
to be efficient and that's really the aim of the 9
ADVANCE Act. We really need it to be modernized. I 10 know we have this 50.46(a) rule from 2010, okay, there 11 is a lot of aspects in there.
12 We're not asking for, I don't think, a 13 lot, but just to modernize it to the current 14 standards. You are going to hear a lot about that, 15 and so that's why we say a modern risk-informed and 16 efficient rule, okay, in line with the ADVANCE Act.
17 It's not there just for talking points. It's really 18 there to be more efficient.
19 If we don't have the efficiency you're not 20 going to see the amount of applications coming in and 21 changes to -- And that was the graphic in the 22 beginning of the slide deck shows it for a carbon-free 23 future, okay.
24 Next slide. So, again, I'll just go over, 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
72 you know, Jason had a great presentation this morning 1
talking about the existing UF6 packages to ship to up 2
to 10 percent with the small modifications that we are 3
talking about here.
4 That was a big deal. That is a really big 5
deal for us having the transportation and logistics 6
assets to be able to ship LEU+, okay. Allowing LEU+
7 is also a huge improvement.
8 The control room dose criteria, we believe 9
that's a very big improvement, okay. You know, can we 10 get a little better there, possibly in the future, to 11 credit some of those operator actions I talked about 12 that we learned a lot from during the Fukushima event 13 and the post-Fukushima rules.
14 So Reg Guide 1.183 we have two I believe 15 pre-submittal meetings this quarter from two 16 utilities, two PWRs, who are using REV-1. We have 17 multiple utilities coming in and thinking about how 18 they're going to use REV-2 once it's in this rule.
19 I particularly have had conversations with 20 utilities who are waiting for when it becomes a draft 21 version, fully up to the Commission it gets out, so 22 they can start putting their development of their 23 package to NRC on REV-2, using REV-2, okay. So that 24 is where we are using the experience that we learned 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
73 out of the workshops to then put forth here and the IE 1
rulemaking workshops.
2 This one down here, large-break LOCA is 3
beyond design basis. That is big. I think that is 4
recognition of the fact that really the risk 5
significance and comparison to other postulated 6
accidents of what the real risk is for large-break 7
LOCA, okay.
8 We believe there is a lot more room there 9
to build on, but openness to this concept is a big 10 deal, okay.
11 The last bullet, you heard that today in 12 terms of going up to the 10 percent. But, again, 13 there are particular aspects that you heard even 14 during the discussion today that remain deterministic 15 and prescriptive, you know.
16 We really need to think about what those 17 requirements are, or the proposed requirements are, 18 and the additional burdens that are associated with 19 that, associated with the risk to the public health 20 and safety, okay.
21 That's where the delta CDF and delta LERF, 22 you know, taking some of those requirements or those 23 prescriptive requirements and try to transfer them 24 into, Like comparing them to what the ask is versus 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
74 what the benefit would be to the public. We haven't 1
seen that yet, okay.
2 Next slide. I don't want to delve too 3
much into this, but, you know, really the 24-month 4
cycle is something that many PWRs are going after 5
right now and the more I go to these meetings with 6
Industry the more I see more and more PWRs embracing 7
24-month cycles.
8 We
- are, Like I
- said, there are 9
applications in-house now going for 24-month cycles 10 for four PWRs, I believe, and we have more coming, 11 okay, and there are several more in terms of power 12 uprates.
13 Next slide. That's where -- I think you 14 heard it at the last meeting, we had four utilities 15 come in and talk about what they are interests are.
16 Jim is here to represent those types of questions and 17 comments as well.
18 You know, just in the last couple weeks, 19 I think this number is low now. I think we're 20 actually going to be higher than this by a 21 considerable amount, okay, because I heard from two 22 other utilities who are now looking to do this, okay.
23 So, again, you know, let me give this 24 background. A year and a half ago we had this survey 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
75 done and it was less than 50 percent and about two 1
gigawatts electric, okay, a year, year and a half ago 2
in terms of the first survey.
3 The second survey came out last fall and 4
it came out to 70 percent of the sites with three 5
gigawatts electric. I believe you are going to see 6
more than that in the -- If we did a survey today or 7
if we do it again, we will do it again this fall, and 8
I believe you are going to see it even grow bigger 9
than that, okay.
10 And this is incentivized by the IRA and 11 really by the ADVANCE Act, okay. One goes this with 12 the other in terms of trying to generate more carbon-13 free electricity.
14 Now the power up for the 24-month cycles, 15 the risk-informed LOCA, there is a lot of folks who 16 were here back in 2010, saw the risk-informed 17 50.46(a), and had the same kinds of concerns over the 18 implementation back then as they have today.
19 So this number in terms of nearly 50 20 percent of the sites are looking for the extended fuel 21 cycles and risk-informed LOCA are seeing a lot fewer 22 interest in the risk-informed LOCA now because of the 23 uncertainty associated with it.
24 Would that number increase? Yes. There 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
76 would be more interest in risk-informed LOCA, however, 1
again, it's about implementation.
2 Next slide. That's where our prioritized 3
concerns are, okay. So our concerns, I've broken them 4
down here, but last time we talked about four 5
different areas. We're going to talk about the four 6
different areas, but I want to bring up the ones in 7
prioritized sequence here.
8 Everything rolls up to implementation, 9
okay, and so our real concern is similar to what 10 happened in 2010 and why you're seeing less interest 11 in the risk-informed LOCA aspects of implementation of 12 that by the utilities.
13 Because of the burden that was there back 14 in 2010 there seems to be more burden than now on the 15 50.46(a) piece as well as just, it's just not, the 16 squeeze is too, is more than the benefits are there 17 for, okay, and that's what was written back then and 18 is more so today, okay.
19 So we really think that there needs to be 20 a consideration to the improvements because a lot of 21 things changes since 2010. A lot of things have 22 changed.
23 So, therefore, we are looking at a lot of 24 the duplication for the additional requirements that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
77 were really contrary to the things Like in Reg Guide 1
1.200, Reg Guide 1.174, the requirements are there.
2 We have had multiple revisions of those 3
since 2010 and so, therefore, we would Like to see the 4
requirements that are associated with them to be in 5
line with the modern approaches of 1.200 and 1.174.
6 So these are the types of things that we 7
are talking about, the seismic issues, we've heard 8
about 1903, you know. Is it in line with what the 9
past 2010 rule and plant-specific requirements versus 10 what was done for DG-14, or, sorry, for the 50.54 11 order after Fukushima related to the seismic issue, so 12 I just want to go over that.
13 I think this is where I would Like to end 14 it, but there is -- We need to think about these 15 burdens with respect to public health and safety and 16 what is really necessary versus what is unnecessary.
17 That's where I think the question is, is 18 this for managing plant assets or is it for public 19 health and safety. I think that's the question that 20 we are asking ourselves internally what is necessary, 21 okay, and for the latter.
22 Next slide. Okay, so this we've got to 23 give a shout out to the Staff, Theresa and to your 24 folks, for some of the changes that were made between 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
78 December and January and January to today.
1 I saw these slides a few days ago, so this 2
is -- So these slides were slides were prepared well 3
before that, so please know that this -- I just give 4
this caveat that the Staff's changes, thank you very 5
much for the changes, we will look at them and see, 6
you know, but I think that the path, the concern on 7
this one was addressed in a lot of ways where it 8
allows for alternate TBS approaches that, as you've 9
mentioned, you were asking about, Alternative 5, 10 Modified Alternative 5 as we see it, Modified 11 Alternative 5 for the EPRI alternate licensing 12 strategy.
13 Allowing those changes to allow us to use 14 that, I can tell you there is a lot of PWRs out there 15 who are very interested in using that approach, and so 16 that was a very positive change.
17 I think that some of the inspection part 18 of it, as you heard during the discussion here, some 19 of it has a ways to go there, and decide, determine 20 where those inspection requirements should be to 21 maintain public health and safety.
22 So, let's see here, what else. I think 23 you hit it. I don't know if we need to go over this 24 slide much more because I think you -- So we can go to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
79 the next slide.
1 So stipulated predictability. You know, 2
this is where when you talk about analysis paralysis 3
and this is where we are seeing that areas and some of 4
the wording about leaving it up to Staff determination 5
and not having it in a Reg Guide or having some 6
predicable path in a Reg Guide is a concern to us 7
because that leads to analysis paralysis.
8 We talked about Draft Guide 1428 last time 9
with the multiple flow charts and multiple places 10 where you make, the Staff makes their determinations, 11 and each one of them can take, probably could take, 12 you know, a lot of time for each one of those.
13 So these are the areas where when we are 14 talking about stability and predictability it leads up 15 to the implementability of the rule. So we heard 16 about best estimate, so I don't want to talk about 17 that. That was really in line with some of the areas 18 we were looking at in terms of nominal values.
19 If we were to do any analysis post for a 20 large-break LOCA if it's beyond size and it's let's 21 say beyond design basis accident now, I think there 22 was a question about whether we should be doing 23 anything.
24 I think with Staff and what we have 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
80 learned with ATWS and other things where those are 1
beyond design basis accidents, this was also another 2
area where we compromised and said that this may be a 3
path forward to meet the schedule that we were talking 4
about, that if we were to use a true best estimate for 5
beyond design basis large-break LOCA this may be a 6
better place to meet in the interim with this rule 7
package, but, again, that could be up for further 8
workshops.
9 I think that's really -- I would love to 10
-- Oh, the backfit and forward fit, we talked about 11 that last time as well with respect to this voluntary 12 rule. We are concerned with Like, for example, back 13
-- We did get the change in the LOCA definition, see 14 the second sub-bullet there, and for the forward fit 15 and backfit that was a big concern.
16 We appreciate the Staff for returning the 17 LOCA definition to historic norms, but, again, that 18 concern over backfit and forward fit, looking into, 19 for example, the breakaway oxidation testing and 20 things Like along those lines, we really want to make 21 sure that we are backfitted into other requirements 22 for the legacy fleet that isn't going to be 23 incorporating high enrichment or higher burn-up fuel.
24 Next slide. So it gets into the breakaway 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
81 oxidation. We do believe that the breakaway oxidation 1
testing requirements should be removed. We don't 2
think it should be in the rule.
3 With respect to it being a technology 4
neutral, we do believe that when you put in into the 5
rule the names or the cladding alloys that are 6
approved it's not technology neutral anymore and you 7
have to come in with exemptions if you want to do a 8
new alloy cladding or if you have another alloy 9
cladding you come up with.
10 So in this way we would rather not have to 11 do exemptions in perpetuity whenever new alloys come 12 in. Have those types of requirements in a reg guide 13 or have those names in a reg guide where it can be 14 easily addressed and not have to go through a 15 rulemaking again every time we have to go and want to 16 put in new alloys. So that's another one that we 17 thought about.
18 We also believe that the concerns over the 19 augment inspections, you know, this again I think we 20 need to think of it in terms of a lot of those 21 modernized, all the things that we did post-Davis-22 Besse and take a look in all the other inspections 23 that we've done, all of the augmented inspections that 24 we've done, all the ASME code requirements, okay.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
82 We want to make sure that also these 1
inspections are, you know, there is the Data Quality 2
Act, there is these OMB circulars that require the NRC 3
to use the consensus of Codes & Standards whenever 4
practical, okay, and are prescriptive, deterministic.
5 Additional augmented inspections outside 6
of the process is that reasonable? We're unsure about 7
that and I think that's where, again, we need to think 8
about it with risk in mind, risk to public health and 9
safety and not to asset management.
10 And then the legacy reporting process, 11 these are things that we believe that there is a lot 12 of reporting requirements that were part of the older 13 2010 rule that we need to think about what makes sense 14 and what just needs to be deleted because there are 15 either duplicative, triplicative types of redundant 16 reporting requirements.
17 So these are things that we can work out 18 through workshops with the Staff. I think that -- I 19 think we have one more slide. I think basically we 20 would Like to see a more realistic, you know, we would 21 Like to enable more realistic operational margins.
22 We are in a place now where we've had 23 LOCAs on the books for over 50 years, okay, and since 24 that time we have now created new sciences in fracture 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
83 mechanics, new sciences to the classic fracture 1
mechanics, new sciences in in-service inspection, 2
applied physics in terms of being able to inspect 3
welds with ultrasonics and not just radiographs, okay.
4 We have had all this new work to be able 5
to do component integrity calculations and we're still 6
in the same spots as we were in a lot of cases in 7
terms of some of the ways we evaluate LOCA and we're 8
not looking at it also from sometimes in a risk-9 informed perspective.
10 Therefore, what we are saying is how do we 11 enable the more realistic operational margins, ensure 12 safety, we do not want to have any safety problems 13 with power uprates or putting in new fuel, okay, but 14 we have these new operational margins that we think we 15 can leverage to get more benefit to the public.
16 I don't want to belabor all of this, we 17 talked about it at the last meeting, if there is 18 anything else you would Like to hear I can chime in 19 and answer, but with that I'll just turn it over to 20 you for a second time.
21 CHAIR KIRCHNER: Thank you, Al, for doing 22 that so efficiently. So, Members?
23 MEMBER HARRINGTON: Just quickly, have you 24 started with the Staff, this is kind of a dual 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
84 question for both of you, have you started the 1
conversations about planning these workshops?
2 There is a lot of specific topics and my 3
sense is much of this can be improved and worked out 4
through those workshops but they need to be carefully 5
thought out, carefully planned, scheduled, work done 6
to prepare for them, it's not just Like show up on a 7
Tuesday and let's have a conversation.
8 MR. CSONTOS: Oh, yes, right. And that's 9
why I was down at the EPRI NTC meetings because we 10 were looking at getting the technical information to 11 be developed, getting the funding and everything 12 associated with White Papers and all the other things 13 that we want to bring to bear to provide as input to 14 these workshops.
15 It's not just get together and chat. It's 16 really building a technical basis for going forward 17 with the safety argument, okay. And in this case we 18 have to also be mindful of the rulemaking process, and 19 I don't want to get the Staff in trouble here by 20 breaking the process rules, okay.
21 The Staff has to send this up to the 22 Commission with your approval, okay, and then the 23 Staff, or the Commission, reviews it and then sends it 24 back out for public comment, and that's when we can 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
85 officially start on many of these areas.
1 We would love to start right away, but 2
what we are doing on our end is developing a lot of 3
these White Papers and trying to get things in order 4
to support those workshops that I hope will start, you 5
know, as early as spring sometime on maybe other 6
topics, but on topics that are specific to the 7
rulemaking, correct me if I'm wrong, Theresa, and you 8
can speak to it, we want to make sure we don't, we 9
want to follow the rulemaking process.
10 MR. STAVELY: Jim Stavely, PSEG. What I 11 would Like to add to that was I was the Industry 12 sponsor for Reg Guide 1.183 and what really came out 13 of that was the value of the plan, as you are 14 indicating workshops, is you have to prep for them, 15 you have to have agreement on the presentations, and 16 it's a great interactive evolution that can move the 17 regulations and the supporting reg guides further 18 along, but it needs that prep to be able to do it.
19 As Al said, it's not a chat to see what's 20 your opinion, what's my opinion, it's the idea of what 21 can we do, what is viable in the schedule to get back 22 to, as Al said, we really need that schedule to be 23 maintained based on the plans and actually the 24 activities in process by the various utilities to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
86 proceed with this assuming the rule keeps to that 1
schedule and it's implementable, but we need to make 2
this work.
3 The workshops, as you described, there is 4
still is opportunity for the Industry and the Staff to 5
be able to improve this rulemaking and supporting 6
guidance and the workshops are key to make that happen 7
and to maintain schedule.
8 CHAIR KIRCHNER: We're going to let the 9
Staff make a comment now.
10 MS. CLARK: Just one clarification that 11 Joe will provide based on one of the slides.
12 CHAIR KIRCHNER: Yeah.
13 MR. MESSINA: Yes. It was stated that the 14 rule that it should be technology neutral with respect 15 to cladding alloys and exemptions would be required 16 for cladding alloys.
17 This rule is technology neutral. You can 18 use your radium nitride and silicon carbide even and 19 not require an exemption. There's nothing that would 20 require an exemption for different alloys for fuels.
21 MEMBER HARRINGTON:
That's what I
22 understood.
23 MR. MESSINA: Yes.
24 MEMBER HARRINGTON: Yeah.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
87 MR. MESSINA: I wanted to make that 1
clarification. Thank you.
2 CHAIR KIRCHNER: Thank you, Al, thank you, 3
Jim, and thanks to the Staff for their presentations, 4
too. At this point, Ron, let's see --
5 MEMBER BALLINGER: Are we bound to go for 6
public comment?
7 CHAIR KIRCHNER: Yes, we should.
8 (Simultaneous speaking.)
9 CHAIR KIRCHNER: Public comment, yeah, 10 that's where I was going. Thank you. Okay, for those 11 listening in, those in the room, if you wish to make 12 a comment please do so, just state your name, 13 affiliation as appropriate, and make your comment.
14 Just unmute yourself and you can go ahead, 15 Ed Lyman. Go ahead, Ed.
16 MR. LYMAN: Thank you. It's Ed Lyman from 17 Union of Concerned Scientists. Can you hear me?
18 CHAIR KIRCHNER: Yes. Go ahead.
19 MR. LYMAN: Yes. So I probably should 20 have prepared some remarks in advance, but I would 21 just Like to express my view. Stepping back in what's 22 going on here and, you know, NEI purports to speak to 23 what's good for public health and safety and I don't 24 believe that they are.
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
88 What we're talking about here is ensuring 1
that fuels that are used in the U.S. reactor fleet are 2
fully qualified and tested to ensure that they are 3
consistent with the safety basis that the public 4
expects them to be.
5 We know that that isn't the case today.
6 We know that the fuels and claddings that are in 7
reactors today are being radiated to burn-ups that are 8
beyond what the existing rules -- Well, the existing 9
rules do not account for those materials at the burn-10 ups that that they are currently allowed to use in 11 reactors.
12 What we are talking about moving forward 13 is instead of solving that problem, which the original 14 50.46© would have to some extent, they are talking 15 about going to regimes pushing fuel well beyond the 16 limits that are already not consistent with the 17 current safety basis, talking about power uprates, 18 increased burn-ups, longer fuel cycles with new 19 materials, and then essentially saying that they don't 20 have to be tested to qualify to those conditions, and 21 that is just wrong.
22 I would just invite the Committee to step 23 back and look at the history again and where we are 24 and how the process that was originally the ATF 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
89 process, which was originally initiated as an attempt 1
to increase safety margin after Fukushima, has been 2
perverted into pushing fuels, pushing reactors into 3
spaces where safety margin is going to be degraded, 4
totally in opposition to the original goal of that 5
program, and that is just wrong.
6 So I just wanted to provide that greater 7
context here because I am very concerned about the 8
direction things are going in, especially if the rules 9
are changed to reduce or eliminate the need to 10 actually demonstrate the safety of these new fuels and 11 materials at these extended operating regimes. Thank 12 you.
13 CHAIR KIRCHNER: Okay. Further comments 14 from the public?
15 (No audible response.)
16 CHAIR KIRCHNER: I'm not hearing any.
17 Then at this point I think we are going to recess and 18 return at 1:15 Eastern Time. So we are in recess.
19 Thank you, everyone.
20 (Whereupon, the above-entitled matter went 21 off the record at 12:20 p.m.)
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
©2025 Nuclear Energy Institute Al Csontos - NEI Director, Fuels IE Rulemaking:
Industry Feedback January 16, 2025
©2025 Nuclear Energy Institute 2 LARs for uprates and/or advanced fuels are on the way IE rule and schedule are vital to industry strategic plans Draft IE Rule from the recent ACRS meetings has many appropriate improvements, but major concerns remain Industry feedback remains consistent with recent NEI letters:
- March 2023 (ML23107A230)
- January 2024 (ML24023A604)
ACRS should allow the draft IE rule for Commission review Workshops needed for industry engagement on concerns IE Rulemaking Key Messages ADVANCE Act alignment for a modern, risk-informed, and efficient IE Rule
©2025 Nuclear Energy Institute 3 Generally, beneficial impacts with the overall rule package:
- Allows increase enrichments to LEU+
- Improved risk-informed control room dose design criteria
- RG 1.183 revisions permit some units to move forward with strategic plans
More realistic modeling of potential release paths
NRC workshops yielded a more predictable, durable, and stable RG
- Openness to LBLOCA as BDBA has potential for significant improvements
- NUREG-2266 for up to 10 wt% U-235 and 80 GWd/MTU burnup Specific areas remain deterministic, prescriptive, and not risk-informed with additional burdens and inefficiencies resulting in high uncertainty to implementation IE Rulemaking Key Messages
©2025 Nuclear Energy Institute 4 Enabling Advanced Fuel Technologies SAFELY SUSTAIN THE FLEET Enhanced Fuel Performance Enhanced Fuel Reliability Improved Operational Flexibility Fuel Cycle Optimization Accelerate ATF Fuel Transition 20% Less Waste &
$3.5 Billion Savings
$9.4 Billion in Industry Fuel Savings 24 Month Refueling Cycles ATF/LEU+/HBU fuels are complementary to uprates and enabling in some cases Modern advanced fuel technologies can:
- Enable 24-month fuel cycles for PWRs
- Less waste = improved safety/fuel efficiency
- Improve plant resiliency and performance
- Increase potential for power uprates
- Improve economics for fleet sustainment On track to meet industrys goal to deploy batch quantities in the mid-to-late 20s:
Applications for 24-month cycles submitted Efficient NRC licensing for advanced fuels and uprates by 2027 with the IE rule needed
©2025 Nuclear Energy Institute 5 Key takeaways:
- >70% of sites have a level of interest/planning for one or more power uprates with a combined capacity increase of 3 GWe
- Nearly 50% of sites have varying interest/plans for one or more of the enabling changes (ATF/
LEU+, Extended Fuel Cycles, and/or RI LOCA) https://www.nei.org/resources/reports-briefs/the-future-of-nuclear-power-2024-survey 2024 NEI Future of Nuclear Power Survey
©2025 Nuclear Energy Institute 6 2010 50.46a rule: substantial implementation burden compared to the potential benefits obtained (ML100260383 & ML10316027)
Does not reflect improvements, efficiencies, and learnings gained from fleet-wide risk informed change programs since 2010:
- RIEP duplicates requirements for implementing risk informed change programs already communicated in RG-1.200 and RG-1.174
- DG-1428 still requires plant specific seismic analyses even though the industry addressed seismic risk per NRC 50.54 order after Fukushima More stringent criteria with additional unnecessary burdens than currently required, e.g. change control, inspections, reporting, etc.
Prioritized Concern: Implementation
©2025 Nuclear Energy Institute 7 Codifying a prescriptive TBS definition with additional inspection requirements hardwires a single solution pathway:
- May not be applicable or readily implementable for many LWR sites
- May lead to future rulemaking and/or numerous exemption requests
- Assumes that BDBA LOCA treatment is sufficient to address FFRD Rule should allow alternative approaches for defining and implementing TBS with prescriptive requirements moved to RGs Minimal changes in rule language provide more flexibility and durability capable of supporting future regulatory improvements without need for exemption requests, e.g. EPRI ALS, Alt. #4, etc.
Prioritized Concern: Flexibility & Durability
©2025 Nuclear Energy Institute 8 Straightforward implementation of the rule needs regulatory clarity, stability, and predictability to well-defined NRC acceptance criteria:
- Technical areas open to interpretation can lead to analysis paralysis
- Industry appreciates staff returning LOCA definition to historical norms What is meant by best estimate LOCA for breaks above TBS?
- NRC expectations for true best estimate are not clear or predictable
- BDBA analyses should not be obscured by artificial biasing Need a clear and predictable path forward for addressing dispersal Forward fit and backfit guidance needed for this voluntary rule regarding future licensing actions not involving LEU+/HBU Prioritized Concern: Stability & Predictability
©2025 Nuclear Energy Institute 9 Breakaway oxidation testing requirements should be removed:
- NEI March 2023 letter (ML23107A230)
Rules should be technology neutral wrt approved cladding alloys:
- Exemptions would be required for several existing approved alloys Prescriptive augmented inspections result in unnecessary additional occupational dose to plant staff and is not risk-informed Legacy reporting requirements should be updated and/or removed, especially for BDBA LOCA considerations Prioritized Concern: Modernization
©2025 Nuclear Energy Institute 10 IE rule with 50.46a/c would enable more realistic operational margins for advanced fuels and additional power uprates as incentivized in the IRA Alignment of the combined draft rule to Commission direction and intent of the ADVANCE Act for a modern, risk-informed, and efficient regulatory process Industry feedback remains consistent with recent NEI letters:
- Combined/modernized rule with modified 50.46a/c - Mar 23 (ML23107A230)
- IE Rulemaking Regulatory Basis industry comments - Jan 24 (ML24023A604)
Development of a clear, efficient, and durable rule with draft regulatory guides needs full consideration of the holistic implementation pathway for licensees NRC workshops would enable an open and transparent dialogue on the Industrys implementation, efficiency, predictability, and durability concerns Summary
Proposed Rule: Increased Enrichment of Conventional and Accident Tolerant Fuel Designs for Light-Water Reactors February 5, 2025 1
Opening Remarks Theresa Clark Director Division of Safety Systems 2
Overview of Increased Enrichment Rulemaking Philip Benavides Project Manager Reactor Rulemaking & Project Management Branch 3
Issue Identification
- Regulatory Issue:
- Current licensing framework allows for the use of 5.0 weight percent uranium-235; however, technology developments may require numerous exemptions to utilize fuel enriched above 5.0 weight percent.
- Proposed Solution:
- Rulemaking would provide for a generically applicable standard informed by public input, providing consistent and transparent communication, rather than individual licensing requests as discussed in SECY-21-0109, Rulemaking Plan on Use of Increased Enrichment of Conventional and Accident Tolerant Fuel Designs for Light-Water Reactors.
- Commission Rulemaking Plan Approval:
- Staff request to pursue rulemaking and develop a regulatory basis was approved by the Commission via SRM-SECY-21-0109.
4
SRM-SECY-21-0109 Overview
- SRM-SECY-21-0109 was issued on 3/16/22, in response to SECY-21-0109.
- The Commission approved the staffs proposal to initiate a rulemaking to amend requirements for the use of light-water reactor fuel containing uranium enriched to greater than 5.0 weight percent uranium-235.
- Fuel Fragmentation, Relocation, and Dispersal (FFRD) should be appropriately addressed.
- Staff directed by the Commission to take a risk-informed approach.
5
Status of Rulemaking Activity
- The NRC staff issued a regulatory basis on September 8, 2023 (ADAMS Accession No. ML23032A504)
- Stakeholder Involvement:
- Before Regulatory Basis Issued:
- Public Meeting on June 22, 2022 (ML22208A001)
- After Regulatory Basis Issued:
- Public Meeting on October 25, 2023 (ML23319A259)
- Comment Period closed on January 22, 2024
- Publicly shared Fuel Dispersal insights at the NRC's Annual Higher Burnup Workshop on September 3, 2024 (ML24277A161)
- The Increased Enrichment proposed rule package is in concurrence.
- Proposed rule due to the Commission: March 2025 6
Status of Rulemaking Activity 2022 2023 2024 2025 2026 SRM 3/16/22 Regulatory Basis 3/16/22-9/8/23 Public Comment Period 9/8/23-1/22/24 Proposed Rule Package 1/22/24-3/14/25 Commission Review 3/14/25-6/16/25 Revise Proposed Rule 6/17/25-7/17/25 Final Rule Package 9/30/25-9/30/26 Note: Dates listed are estimates only, and thus are subject to change.
Final Rule to Commission 9/30/26 2027 Public Comment Period 7/17/25-9/30/25 7
NRC Staff Presenters
- Charley Peabody, NRR:
- Criticality Accident Requirements (10 CFR 50.68)
- Jason Piotter, NMSS:
- General Requirements for Fissile Material Packages (10 CFR 71.55)
- Elijah Dickson, NRR:
- Control Room Requirements (10 CFR 50.67 and GDC-19)
- Joseph Messina, NRR:
- Fuel Fragmentation, Relocation, and Dispersal (10 CFR 50.46a) 8
Criticality Accident Requirements of 10 CFR 50.68 Charley Peabody Nuclear Systems Performance Branch NRR 9
Criticality Accident Requirements of 10 CFR 50.68
- This rulemaking would amend the current 5.0 weight percent U-235 limit in 50.68(b)(7) and allow for an alternative between the existing 5.0 weight percent U-235, or a plant-specific criticality safety limit based on the limit specified in a licensees or applicants operating license.
- Licensees would be allowed to increase enriched fuels above 5.0 weight percent as long as this increased enrichment level is approved specifically in their technical specifications design features or equivalent part of the operating license as a part of a fuel transition license amendment request.
10
Questions?
11
Packaging Requirements of 10 CFR 71.55 Jason Piotter New Fuels Team NMSS 12
Packaging Requirements of 10 CFR 71.55
- Current transportation regulations are adequate to certify UF6 transportation packages with material enriched up to 20.0 weight percent U-235. (10 CFR 71.55(b), 71.55(c), 71.55(g)).
- 10 CFR 71.55(g), specific to UF6 transportation packages, is an exception to 71.55(b), which requires the consideration of moderator when performing criticality calculations. For UF6 packages with enrichment levels up to 5.0 weight percent U-235 certified under 71.55(g), moderator does not have to be considered in criticality calculations.
13
Packaging Requirements of 10 CFR 71.55
- This rulemaking would amend 10 CFR 71.55(g) to allow the current exception of UF6 enriched up to 5.0 weight percent U-235 to expand to 10.0 weight percent U-235. This amended rule would require a defense-in-depth design feature for those packages containing UF6 enriched between 5.0 and 10.0 weight percent U-235.
14
Questions?
15
Control Room Design Criterion of 10 CFR 50.67 and GDC-19 Elijah Dickson Radiation Protection and Consequence Branch NRR 16
Control Room Design Criterion of 10 CFR 50.67 and GDC-19:
Summary of Regulatory Issue
- This rulemaking would amend the control room design criteria from the current 5 rem (0.05 Sv) total effective dose equivalent (TEDE) to a revised value of 10 rem (0.10 Sv) TEDE; the value may range up to 25 rem (0.25 Sv) TEDE with consideration of the plant-specific risk profile or risk information.
- The amended rule, and subsequent guidance, would align with Commission direction provided in SRM-SECY-98-144 to take a risk-informed, performance-based approach to regulations and guidance.
17
Questions?
18
Fuel Fragmentation, Relocation, and Dispersal Joseph Messina Nuclear Methods and Fuel Analysis NRR 19
Fuel Fragmentation, Relocation, and Dispersal
- This rulemaking would enable entities to voluntarily recategorize large-break loss-of-coolant accidents (LOCA) as beyond design basis accidents, leveraging the previous 50.46a rulemaking, which was delivered to the Commission as a draft final rule in 2010, but rescinded due to Fukushima and a lack of industry interest.
- This rulemaking would divide the current spectrum of LOCA into two regions delineated by a transition break size (TBS). The smaller region (breaks up to the TBS) would be treated same as all breaks under the current 10 CFR 50.46 emergency core cooling system (ECCS) rules. The larger region (breaks greater than TBS) would be allowed to be analyzed using best-estimate modeling and more realistic assumptions based on their lower likelihood of occurrence.
20
Fuel Dispersal
- While the wording is not significantly different regarding coolability than 50.46, the NRC staff added a discussion in the Federal Register Notice (FRN) Preamble (formerly known as Statements of Consideration) that adds clarification on the interpretation of coolability:
- The NRC can envision that some amount of dispersed fuel can remain coolable and safe during a LOCA, therefore the NRC finds that if it can be shown to be safe, then it may be acceptable.
- True best-estimate modeling and realistic assumptions are expected to significantly reduce or eliminate the calculated potential for fuel dispersal
- DG-1434 provides guidance on fuel dispersal
- While this approach does not explicitly address non-mechanistic approaches to evaluating FFRD, as described in other alternatives in the IE Regulatory Basis, other licensing pathways exist
- E.g., the topical report review process
- The performance-based criteria are expected to facilitate option of these alternatives (including a less prescriptive interpretation of core coolability) 21
Changes Made Since January ACRS Subcommittee Meeting Weld inspections:
50.46a(b)(3) requirement to inspect 10% of similar metal welds on piping larger than the TBS has been replaced with an NRC-approved sampling of similar metal welds.
Allowing operating reactors to define their own TBS:
Transition break size (TBS) for reactors licensed under this part before December 31, 2015, is a break area equal to the largest cross-sectional flow area of the reactor coolant pressure boundary piping excluding the hot leg, cold leg, or crossover leg piping for a pressurized water reactor, or the largest cross-sectional flow area of either the feedwater line or residual heat removal line inside containment for a boiling water reactor, or a plant-specific alternative break area. For reactors that are or will be licensed under this part after December 31, 2015, and for light-water reactors (LWRs) that are or will be licensed under part 52 of this chapter, the TBS will be determined on a plant-specific basis.
Clarification on alternative approaches:
Added clarification in the Preamble and SECY paper that the performance-based view of coolability in 50.46a(f) and the fact that fuel dispersal is not necessarily incompatible with coolability can facilitate alternative approaches to addressing FFRD. The staff plans to continue engaging with industry on other approaches (e.g.
modified Alternatives 4 and 5) via licensing interactions and workshops.
22
Proposed 50.46a Highlighted Requirements The primary requirements of 50.46a are:
- Evaluation of plant-specific applicability of the TBS
- Evaluation that changes made do not invalidate the TBS
- A risk-informed evaluation process is established to analyze changes enabled by 50.46a Changes must be kept to very small risk increases (i.e., CDF 1E-6/rx.yr. and LERF 1E-7/rx.yr.) and the overall risk must remain small
- Principal ECCS criteria Maintain fuel coolability Long-term cooling
- Fuel performance criteria:
Address cladding degradation phenomena Maintain fuel coolability Avoid explosive concentration of combustible gas Long-term cooling
- Breaks at or below the TBS must continue to have a high probability that the ECCS and fuel performance criteria are met
- Breaks above the TBS must demonstrate that ECCS and fuel performance criteria are met to at least a best-estimate level 23
24 50.46a Rule High-Level Highlighted Requirements 50.46a(c)(1)(i) and (c)(3)(i): Evaluate applicability of the TBS to the licensees facility 50.46a(b)(3) and (c)(ii): Inspect an approved sampling of similar metal welds on piping > TBS 50.46a(c)(1)(iv)-(v) and (c)(3)(iii)-(iv): Risk-informed evaluation process for proposed changes made under 50.46a 50.46a(h): Acceptance criteria for changes made under 50.46a 50.46a(f)(1): fuel performance criteria. Must have NRC-approved limits that:
Guidance DG-1428, Plant-Specific Applicability of the Transition Break Size DG-1426, An Approach for a Risk-Informed Evaluation Process Supporting Alternative Acceptance Criteria for Emergency Core Cooling Systems for Light-Water Reactors DG-1263, Rev. 1, Establishing Analytical Limits for Zirconium-Based Alloy Cladding DG-1434, Addressing the Consequences of Fuel Dispersal in Light-Water Reactor Loss-of-Coolant Accidents DG-1261, Rev. 1, Measuring Breakaway Oxidation Behavior" DG-1262, Rev. 1, Determining Post-Quench Ductility
- i. Address cladding degradation phenomena ii. Maintain fuel coolability iii. Avoid explosive concentration of combustible gas iv. Ensure long-term cooling 24
TBS development Recent Confirmation of the TBS Technical Basis:
NUREG-1829 Confirmation:
Internal and External Elicitation Impact of Recent Operational Experience Probabilistic Fracture Mechanics Study International Operational Database Study NUREG-1903 Confirmation:
Evaluated three cases: unflawed and flawed piping failure and indirect piping failure by other components and component supports.
Used most recently updated seismic hazard curves for the assessment For unflawed piping, failure probabilities were significantly low compared to the 1E-05 per year frequency used as a basis to establish the TBS.
Flawed piping and indirect failure frequencies expected to be < 1E-05 per year but more comprehensive, plant-specific analysis needed to confirm.
TBS Confirmation:
LOCA frequencies and TBS are applicable if plant specific applicability is demonstrated.
New designs can develop plant specific TBS.
Inspection of the piping welds with diameters greater than the TBS are needed to ensure LOCA frequencies remain applicable.
Historic TBS Technical Basis:
Passive System LOCA frequencies developed for generic BWR and PWR plants through an expert elicitation process (NUREG-1829)
Accounted for panelist uncertainty and variability among responses Used results as the starting point for selecting the transition break size Increased TBS to address additional factors and to promote regulatory stability Considered other types of LOCAs Accounted for plant piping design and operating experience Performed confirmatory study to determine if risk of LOCAs > TBS due to rare seismic was acceptable (NUREG-1903)
Risk due to unflawed and flawed direct piping failures expected to be acceptable for most, if not all, plants Risk due to indirect piping failures acceptable for two cases evaluated Seismic risks, however, are plant-specific, making it difficult to generalize results Qualitative Quantitative 25
Cladding Testing: DG-1261 through 1263 DG-1261, Rev. 1: Measuring Breakaway Oxidation Behavior
- NRCs LOCA program showed that minor changes in alloy composition or manufacturing processes can have significant impact on breakaway oxidation behavior
- Defines an experimental technique capable of determining the effect of composition changes or manufacturing changes on the breakaway oxidation behavior
- Discusses both initial testing and periodic confirmatory testing DG-1262, Rev. 1: Determining Post-Quench Ductility
- Defines an experimental technique to measure the ductile-to-brittle transition for the zirconium-alloy cladding material
- Provides detailed discussion of determining the ductile-to-brittle transition CP-ECR for a given hydrogen level; allows for binning results with similar H content DG-1263, Rev. 1: Establishing Analytical Limits for Zirconium-Based Alloy Cladding
- Describes an approach to establish limits to address zirconium-alloy cladding degradation phenomena Analytical limits for post-quench ductility and breakaway oxidation PCT limit to address post-quench ductility also protects against higher-temperature degradation mechanisms
- Provides guidance on how to consider the impact of oxygen diffusion from inside surfaces on cladding degradation
- Provides default cladding hydrogen uptake models for currently approved cladding models
- Provides an analytical limit for combustible gas generation.
26
True Best-Estimate
- LOCAs above the TBS must be analyzed to at least a true best-estimate level.
- The NRC staff specified in the Preamble of the proposed rule FRN that true best estimate analyses are based on nominal inputs, without conservative biases, and without adding uncertainties.
- The NRC staff plans to align with industry on a definition in workshops in the final rule phase.
27
Questions?
28
Backup Slides 29
Associated Guidance
- Control Room Design Requirements (10 CFR 50.67 and GDC-19)
- DG-1425, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors
- Fuel Fragmentation, Relocation, and Dispersal
- DG-1261, Revision 1, Measuring Breakaway Oxidation Behavior
- DG-1262, Revision 1, Determining Post-Quench Ductility
- DG-1263, Revision 1, Establishing Analytical Limits for Zirconium-Based Alloy Cladding
- DG-1426, An Approach for a Risk-Informed Evaluation Process Supporting Alternative Acceptance Criteria for Emergency Core Cooling Systems for Light-Water Reactors
- DG-1428, Plant-Specific Applicability of the Transition Break Size
- DG-1434, Addressing the Consequences of Fuel Dispersal in Light-Water Reactor Loss-of-Coolant Accidents 30