ML18057B074
| ML18057B074 | |
| Person / Time | |
|---|---|
| Issue date: | 02/07/2018 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Widmayer D | |
| References | |
| NRC-3520 | |
| Download: ML18057B074 (212) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Future Plant Designs Sub-Committee Open Session Docket Number: N/A Location: Rockville, Maryland Date: February 7, 2018 Work Order No.: NRC-3520 Pages 1-212 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
1 1
2 3
4 DISCLAIMER 5
6 7 UNITED STATES NUCLEAR REGULATORY COMMISSIONS 8 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 9
10 11 The contents of this transcript of the 12 proceeding of the United States Nuclear Regulatory 13 Commission Advisory Committee on Reactor Safeguards, 14 as reported herein, is a record of the discussions 15 recorded at the meeting.
16 17 This transcript has not been reviewed, 18 corrected, and edited, and it may contain 19 inaccuracies.
20 21 22 23 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
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ADVISORY COMMITTEE ON REACTOR SAFEGUARDS (ACRS)
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FUTURE PLANT DESIGNS SUBCOMMITTEE
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OPEN SESSION
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WEDNESDAY FEBRUARY 7, 2018
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ROCKVILLE, MARYLAND
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The Subcommittee met at the Nuclear Regulatory Commission, Two White Flint North, Room T2B1, 11545 Rockville Pike, at 8:59 a.m., Dennis Bley, Chairman, presiding.
COMMITTEE MEMBERS:
DENNIS BLEY, Chairman RONALD G. BALLINGER, Member CHARLES H. BROWN, JR., Member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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2 MICHAEL CORRADINI, Member VESNA B. DIMITRIJEVIC, Member WALTER L. KIRCHNER, Member JOSE A. MARCH-LEUBA, Member DANA A. POWERS, Member HAROLD B. RAY, Member PETER C. RICCARDELLA, Member GORDON R. SKILLMAN, Member JOHN W. STETKAR, Member MATTHEW W. SUNSERI, Member ACRS CONSULTANT:
STEPHEN SCHULTZ DESIGNATED FEDERAL OFFICIAL:
MARK BANKS GIRIJA SHUKLA ALSO PRESENT:
AMY CUBBAGE, NRO BOB FITZPATRICK, NRR BRIAN GREEN, NRO JIM KINSEY, Idaho National Laboratory IMTIAZ MADNI, NRO NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 JAN MAZZA, NRO SHEILA RAY, NRR JEFF SCHMIDT, NRO JOHN SEGALA, NRO TANJU SOFU, Argonne National Laboratory ANDREA D. VEIL, Executive Director, ACRS
- Present via telephone NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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4 1 P R O C E E D I N G S 2 8:59 a.m.
3 CHAIRMAN BLEY: The meeting will come to 4 order. Good morning. This is a meeting of the 5 Advisory Committee on Reactor Safeguards Subcommittee 6 on Future Plant Designs. I'm Dennis Bley, Chairman 7 of the Subcommittee.
8 ACRS members in attendance are or shortly 9 will be Joy Rempe, Charlie Brown, Walt Kirchner, Jose 10 March-Leuba, Mike Corradini, Dana Powers, Harold Ray, 11 Matt Sunseri, Ron Ballinger, Pete Riccardella, John 12 Stetkar, and Vesna Dimitrijevic.
13 Dr. Stephen Schultz, ACRS consultant, is 14 also in attendance. Mark Banks, filling in for 15 Girija Shukla, of the ACRS staff is the Designated 16 Federal Official for this meeting.
17 The purpose of today's meeting is to 18 review the final Regulatory Guide 1.232 guidance for 19 developing principal design criteria for non-light 20 water reactors.
21 The subcommittee will gather 22 information, analyze relevant issues, facts, and 23 formulate positions and actions as appropriate for 24 consideration by the full committee. The full 25 committee is scheduled to address this matter at the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 1 March 2018 full committee meeting.
2 The ACRS was established by statute and 3 is governed by the Federal Advisory Committee Act, 4 FACA. That means that the committee can only speak 5 through our published letter reports.
6 We hold meetings to gather information to 7 support our deliberations. Interested parties who 8 wish to provide comments can contact our offices 9 requesting time after the Federal Register notice of 10 the meeting is published.
11 That said, we set aside time for 12 extemporaneous comments from members of the public 13 attending or listening to our meetings. Written 14 comments are also welcome.
15 The ACRS section of the U.S. NRC public 16 website provides our charter bylaws, letter reports, 17 and full transcripts of all full and subcommittee 18 meetings, including slides presented at the meetings.
19 Detailed proceedings for conduct of ACRS 20 meetings was previously published in the Federal 21 Register on October 4, 2017. The meeting is open to 22 public attendance. And we have received no requests 23 for time to make oral statements.
24 Today's meeting is being held with a 25 telephone bridge line allowing participation to the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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6 1 public over the phone. A separate teleconference 2 line has also been established to allow participation 3 of staff consultants from DOE laboratories.
4 A transcript of today's meeting is being 5 kept. Therefore, we request that the meeting 6 participants either on the bridge line or 7 teleconference line identify themselves each and 8 every time they speak and to speak with sufficient 9 clarity and volume so they can be readily heard.
10 We request those participants on the 11 public bridge line to keep their phones on mute until 12 they are called on to speak during the public comment 13 period at the end of the subcommittee meeting.
14 Participants in the meeting room should 15 use the microphones located throughout the meeting 16 room when addressing the subcommittee.
17 At this time, I ask that attendees in the 18 room please silence all your cell phones and other 19 noisemakers.
20 And I remind speakers at the front table 21 to turn on the microphone touching it at the bottom 22 where it says push, indicated by the illuminated 23 green light when speaking, and likewise turn it off 24 when you're not speaking. That keeps the bridge line 25 quieter so everybody can hear.
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7 1 We'll now proceed on with the meeting.
2 And I'll call upon John Segala, Chief of the Advanced 3 Reactor and Policy Branch, Office of the NRO, to make 4 introductory remarks.
5 PARTICIPANT: Dennis?
6 CHAIRMAN BLEY: Just before we go ahead, 7 first Dr. Corradini.
8 MEMBER CORRADINI: Just so the members 9 know, I'm a member of the DOE NEAC subcommittee on 10 advanced reactors, or on reactor technology. So I've 11 seen some of the reference material before.
12 MEMBER REMPE: So I also have a similar 13 comment, because of member, in order to comply with 14 Section 10.1 of our bylaws, I have the --
15 CHAIRMAN BLEY: Good for you.
16 MEMBER REMPE: -- knowledge, and I am a 17 member also of this Department of Energy Nuclear 18 Energy Advisory Committee, as well as the former 19 Secretary of Energy Moniz's SEAB task force. And we 20 had to review and provide comments on some of the 21 material that we were provided in preparation of this 22 meeting.
23 CHAIRMAN BLEY: Thank you, Joy. Harold, 24 are you still a member of that?
25 MEMBER RAY: No.
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8 1 CHAIRMAN BLEY: Okay. At this time, 2 John, please go ahead.
3 MR. SEGALA: Well, thank you. So, 4 before we get into too much detail on the non-light 5 water reactor design criteria, I wanted to very 6 quickly provide you an overview of the advanced 7 reactor program, our readiness activities, and some 8 of our past and planned ACRS meetings just so that 9 you can see sort of how this fits in the overall 10 approach that we're taking. Next slide, please.
11 So last March the staff presented the 12 non-light water reactor vision and strategy and near-13 term implementation action plans to the ACRS future 14 plants subcommittee and the full committee meeting.
15 The near-term implementation action plan 16 has six strategies. And you can see them in the top 17 blue boxes across the top there. And we've been 18 working on readiness activities under each strategy.
19 However, we have been focusing our 20 efforts on Strategies 3 and 5 based on 21 recommendations in the ACRS letter from last March.
22 Several items, readiness activities 23 we've completed are shown with the checkmarks in the 24 green boxes. The boxes highlighted in yellow at the 25 bottom under Strategies 3 and 5 are areas that we've NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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9 1 been focusing a lot of our attention on in the near-2 term. And those are also areas that we plan future 3 interactions with the ACRS.
4 The non-light water reactor design 5 criteria box under Strategy 3 represents information 6 that the non-light water reactor designers need early 7 on to proceed with the development of their designs.
8 This effort has been underway since 2013 and 9 represents a more traditional, deterministic approach 10 with some performance-based aspects.
11 Stakeholders have indicated to us that 12 this Reg Guide is of high priority to them, and they 13 would like us to move forward with issuing the final 14 Regulatory Guide.
15 More recently we have been working on the 16 review of the industry-led licensing modernization 17 program, which is the bottom box under Strategy 3, 18 which is a risk-informed, performance-based approach 19 for determining the licensing basis events.
20 The LMP includes four industry white 21 papers. There's the licensing basis event selection, 22 defense-in-depth, PRA, and SSC safety classification 23 white papers, which build off of the NGNP white papers 24 that were submitted back in the 2010 timeframe.
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10 1 papers into a consolidated NEI document and submit 2 that to the NRC, requesting for our endorsement in a 3 Regulatory Guide.
4 If the staff gets to the point where we 5 can come to a decision to endorse the LMP in a Reg 6 Guide, both the non-light water reactor design 7 criteria Reg Guide and separately the LMP Reg Guide 8 would be two acceptable approaches for developing a 9 licensing basis for a non-light water reactor.
10 The outcome of the LMP process may serve 11 to help risk inform some of the non-light water 12 reactor design criteria. And the Reg Guide could be 13 modified in the future if needed.
14 But we feel that the non-light water 15 reactor design criteria Reg Guide as it is is a 16 conservative and acceptable approach moving forward.
17 CHAIRMAN BLEY: John?
18 MR. SEGALA: Yes.
19 CHAIRMAN BLEY: If I remember correctly, 20 you expect to brief us on this in, sometime in the 21 June timeframe, right?
22 MR. SEGALA: Yes, so the next slide, next 23 couple slides I'll get into that. I'll give you the 24 specific dates and --
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11 1 under the boxes under 3? So the first question is 2 the prototype guidance, that has been rolled into a 3 roadmap as an appendix.
4 MR. SEGALA: Yes.
5 MEMBER CORRADINI: Has that been -- I 6 mean, in some sense I do that as an explanatory 7 document for a one sentence in 10 CFR 50.
8 MR. SEGALA: Yes.
9 MEMBER CORRADINI: Has that undergone 10 approval such that it is now the guidance that one 11 follows, or it's still under discussion?
12 MR. SEGALA: So that regulatory roadmap 13 has been finalized. We issued multiple drafts of 14 that. We had multiple stakeholder meetings where we 15 discussed the roadmap as well as the prototype 16 guidance. And then we issued that final. It's on 17 our public website.
18 The prototype guidance, a lot of that is 19 based off of a SECY paper that was written years ago.
20 And we've actually included in part of the prototype 21 guidance the flowchart and the information from the 22 SECY paper.
23 MEMBER CORRADINI: Okay. So my question 24 kind of goes like this. I've read, I don't know 25 which version I've read of the prototype guidance.
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12 1 It seems reasonable as a generalized guide. But does 2 it give enough guidance that if somebody wanted to 3 pursue that path they understand what they have to 4 do, because it struck me as still a bit vague?
5 MR. SEGALA: Well, I guess that remains 6 to be seen.
7 MEMBER CORRADINI: Should I ask the 8 industry that?
9 MR. SEGALA: Yes, it might be a good 10 question. I mean, as we went through the process of 11 submitting it as a draft and soliciting stakeholder 12 feedback, we didn't receive a lot of comments that -
13 - and it didn't really change significantly.
14 But, you know, the requirements of 15 50.43(e) lays out that you need a combination of 16 testing, analysis, and operating experience in order 17 to demonstrate the capabilities of your safety 18 systems.
19 And if, you know, and it goes through a 20 whole process by which you can, you know, do different 21 kinds of testing and leverage different things. And 22 it kind of leaves the prototype as kind of the last 23 resort but, that you could go down that path. We 24 just haven't actually done that.
25 MEMBER CORRADINI: Okay. All right.
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13 1 I'll leave it there, because I guess I've got to make 2 sure I see the latest version to make sure. But at 3 least the version --
4 MR. SEGALA: -- get that.
5 MEMBER CORRADINI: -- the last version I 6 saw is, I was looking for attributes that have to be 7 satisfied in some generalized fashion so that if 8 somebody wanted to pursue that path they actually 9 understood what was expected of them.
10 But let me just move on. So --
11 MR. SEGALA: We can --
12 MEMBER REMPE: Before you move on --
13 MR. SEGALA: We can provide you all a 14 copy of that.
15 MEMBER CORRADINI: Okay.
16 MR. SEGALA: I mean, we --
17 MEMBER REMPE: Where is that, because the 18 version that we got in preparation for this meeting 19 says preliminary draft?
20 And yet there's been -- have we discussed 21 that roadmap at all, because I like a lot of things 22 I see in there like the implementation action plan?
23 And I have a lot of questions about the roadmap. And 24 I don't recall us discussing --
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14 1 a couple years ago.
2 MEMBER REMPE: The regulatory roadmap, 3 but I don't think we did this one, did we?
4 MR. SEGALA: The roadmap isn't really 5 creating a whole lot of new information. It's 6 basically laying out all the different flexibilities 7 we have in the current regulations, whether it's Part 8 50 under the construction permit operating license or 9 whether you're under Part 52 and you're looking at, 10 you know, an ESP design cert, all the different 11 options and standard design approval.
12 And so we kind of go through all the 13 different flexible approaches that we have and the 14 fact that we're willing to engage very early with 15 pre-applicants and talk. We stress a lot the need 16 to establish a regulatory engagement plan or 17 licensing project plan.
18 MEMBER REMPE: How is that going over 19 with the potential applicants --
20 MR. SEGALA: We --
21 MEMBER REMPE: -- or do you even have any 22 that are getting ready to submit --
23 MR. SEGALA: We do have licensing project 24 plans that have been submitted to us. And we're 25 currently working on those in terms of we're actually NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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15 1 implementing what's in there. So we think it's 2 working well.
3 We encourage early discussions with us, 4 provide us drafts. We can provide feedback. The 5 whole idea of the licensing project plan or 6 regulatory engagement plan, which is now what we're 7 calling it, is to have agreement early on so that 8 there's clear expectations that during the pre-9 application phase we understand what the expectations 10 and the outcomes are so that we ensure that you don't 11 just have pre-application meetings for the sake of 12 meetings and have --
13 MEMBER REMPE: Yes, I think there's great 14 --
15 MR. SEGALA: -- unfocused --
16 MEMBER REMPE: -- ideas.
17 MR. SEGALA: Yes.
18 MEMBER REMPE: I just am curious, because 19 I haven't, I guess I missed it if we discussed that 20 before. And I also was interested in some of the 21 discussion about 104, the prototype, and a lot of 22 that in this roadmap.
23 MR. SEGALA: Yes.
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16 1 to talk about that more.
2 CHAIRMAN BLEY: Yes, that's not up for 3 today --
4 MR. SEGALA: Well, we can certainly 5 provide you --
6 CHAIRMAN BLEY: -- but we'd be interested 7 in --
8 MR. SEGALA: We can provide you the 9 updated final version. And then, you know, we can, 10 if you want to have a separate discussion on that, we 11 could do that.
12 MEMBER REMPE: Yes, because especially 13 with the 103 versus the 104 and what would happen if 14 you went above 10 megawatts, for example, and things 15 like that.
16 MR. SEGALA: Okay.
17 MEMBER REMPE: I'm curious on what you're 18 thinking is.
19 MR. SEGALA: Okay.
20 MEMBER CORRADINI: Okay, okay. I'm 21 sorry.
22 MR. SEGALA: That's fine.
23 MEMBER CORRADINI: Can I now go to the 24 yellow boxes?
25 MR. SEGALA: Okay.
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17 1 MEMBER CORRADINI: So is it that if I'm 2 Joe's -- I'll use Member Stetkar's analogy. It's 3 such a good analogy. So, if I got Joe's reactor, do 4 I have to satisfy both the yellow box that says non-5 light water reactor design criteria and the white 6 papers? Is it an either/or, or is it an and? I'm 7 still struggling to figure out, if I apply, what do 8 I have to follow.
9 MR. SEGALA: Well, I mean, technically, 10 the requirements are that you have to establish 11 principal design criteria for your reactor design.
12 So you could come in and completely 13 ignore the Reg Guide on the non-light water reactor 14 design criteria and come up with your own principal 15 design criteria. But you have to justify why those 16 are the appropriate design criteria for your 17 particular design. So the Reg Guide is really 18 optional for them to choose. MEMBER 19 CORRADINI: But --
20 MR. SEGALA: We're trying to give them 21 an example of what, one example of what the staff 22 would find acceptable.
23 But in the end, they're going to have to 24 go through that Reg Guide if they want to adopt the 25 design criteria. And they're going to have to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 1 justify that those are appropriate for their 2 facility.
3 MEMBER CORRADINI: Okay.
4 MR. SEGALA: Now, they could use the non-5 light water reactor design criteria Reg Guide in 6 conjunction with the LMP. And so you could very 7 early on in your preliminary design, you could apply 8 the non-light water reactor design criteria to your 9 design to help you design it.
10 And then the licensing modernization 11 process is actually an iterative process that you go 12 through multiple times along the design development.
13 And then you could use that to fine tune your 14 principal design criteria.
15 MEMBER CORRADINI: So, okay. So I got 16 the first part. The second part I'm still fuzzy.
17 Are we going to talk about the second yellow box today 18 or just the first yellow box?
19 MR. SEGALA: Just the first.
20 MEMBER CORRADINI: So --
21 MR. SEGALA: And then we --
22 MEMBER CORRADINI: So I still don't 23 understand the second yellow box. What you said, I 24 heard what you said. I don't understand how I do it 25 if I were a licensee using, because I thought the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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19 1 four white papers from the NGNP were useful as to 2 what to do and what to avoid the next time we try 3 this. And I'm just trying to see how the two marry 4 together.
5 MR. SEGALA: So the LMP is basically an 6 extension of what was done for NGNP. But I think, 7 you know, to do that, to do a discussion on LMP in a 8 very short period of time --
9 MEMBER CORRADINI: No, that's fine.
10 MR. SEGALA: -- is going to be --
11 MEMBER CORRADINI: But eventually I 12 think --
13 MR. SEGALA: -- difficult.
14 CHAIRMAN BLEY: We do have a subcommittee 15 meeting.
16 MEMBER CORRADINI: Okay. I'm sorry.
17 MR. SEGALA: We'll have a series of 18 meetings, which I'll get to --
19 MEMBER CORRADINI: Okay. Thank you.
20 MR. SEGALA: -- or we can go into that 21 in detail.
22 MEMBER CORRADINI: Thank you very much.
23 MR. SEGALA: So really quick on, the 24 staff is also, if you go under Strategy 5 for 25 emergency planning, we're in the process of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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20 1 developing a proposed rule for a consequence-oriented 2 approach for determining the size of the emergency 3 planning zone for small modular reactors and other 4 new technologies, which include non-light water 5 reactors.
6 Back in April, we shared with the ACRS 7 our draft regulatory basis on that rule. And ACRS 8 elected to wait to have a meeting until after the 9 proposed rule is developed.
10 For the functional containment 11 performance criteria --
12 CHAIRMAN BLEY: Sorry. What's on ONT?
13 MR. SEGALA: Other new technologies.
14 CHAIRMAN BLEY: Oh.
15 MR. SEGALA: So --
16 CHAIRMAN BLEY: So miscellaneous.
17 MR. SEGALA: So originally it was non-18 light water reactors and medical isotope. That was 19 the scope of other new technologies.
20 For functional containment, the staff is 21 developing a commission paper to address the previous 22 commission direction to define performance criteria 23 for design features that limit the release of 24 radioactive materials.
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21 1 this topic have been focused on high temperature gas-2 cooled reactors, another goal of the SECY paper is to 3 get commission approval to a more technology 4 inclusive approach.
5 MEMBER CORRADINI: So, sorry, and again 6 on all these questions that you can defer till later.
7 So, under the, where in the green and the 8 yellow is a discussion about a general procedure or 9 policy on a facility versus modules in the facility, 10 because the EP would be affected by that? The source 11 term would be affected by that. Where is that?
12 MR. SEGALA: Well, we have a series of 13 policy issues that we have laid out for SMRs and non-14 light water reactors. And that policy issue I 15 believe was already addressed.
16 MEMBER CORRADINI: Okay. So then, if 17 it's been addressed, if it comes up in a specific, 18 I'll ask, because I'm still vague. I'm still 19 unclear.
20 MR. SEGALA: So what's your specific --
21 MEMBER CORRADINI: Well, I don't want to 22 pick on a design. So let's say if I have Joe's 23 reactor and Joe has two of them onsite on a facility 24 or 6 or 12, or if I'm into the microreactor fab world 25 that I'm in, 100, do I take every one of the 100 as NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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22 1 the facility to analyze for non-light water reactor 2 design criteria? Or do I take three?
3 What is the process by which one decides 4 what has to be included between the facility and the 5 modules?
6 MR. SEGALA: Yes, and I think the 7 approach is to look at one module at a time. But 8 then we also have to look at is there any conditions 9 under which there are shared systems that you could 10 have a situation where multiple modules could fail at 11 the same time.
12 CHAIRMAN BLEY: Or shared initiating 13 events or shared many other things, operator 14 involvement.
15 MEMBER CORRADINI: So is it, so what I 16 interpret that to mean is it's kind of we're coming 17 here on a case-by-case basis. There might be a 18 policy out there, but the policy will be addressed on 19 a case-by-case basis.
20 MS. CUBBAGE: So we're going to be having 21 a separate meeting --
22 CHAIRMAN BLEY: Amy?
23 MS. CUBBAGE: -- on the --
24 CHAIRMAN BLEY: Amy?
25 MS. CUBBAGE: Amy Cubbage, NRC staff, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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23 1 thank you.
2 We're going to be having a separate 3 meeting on the whole licensing modernization project.
4 But that effort is definitely taking into 5 consideration --
6 MEMBER CORRADINI: Okay.
7 MS. CUBBAGE: -- the multi-module issues 8 and whether you consider a facility, you know, how 9 the PRA is done for a multi-unit --
10 MEMBER CORRADINI: Okay.
11 MS. CUBBAGE: -- module facility. Okay?
12 CHAIRMAN BLEY: Thank you.
13 MEMBER CORRADINI: Thanks.
14 CHAIRMAN BLEY: That's coming up soon.
15 MEMBER REMPE: So one last random 16 question about the modernization project, in one of 17 your implementation action plans you have a statement 18 in there about doing licensing basis events and 19 documenting them for highly prioritized technologies.
20 And I was curious on how that's working out. How do 21 you decide what's highly prioritized?
22 MR. SEGALA: Yes, I'm not sure.
23 MEMBER REMPE: Is it going to be what 24 comes in first?
25 MR. SEGALA: So, say the question.
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24 1 MEMBER REMPE: Well, it's in one of your 2 IAPs, the implementation action plan you had in 3 Section 3.2.
4 MR. SEGALA: Okay.
5 MEMBER REMPE: And it says you're going 6 to document the licensing basis events for highly 7 prioritized technologies.
8 MS. CUBBAGE: So I'd have to look at that 9 language in context. But what I can tell you is the 10 licensing modernization project is completely 11 technology inclusive. And there's no activity 12 currently to work that on a technology or design 13 specific basis.
14 I think we're certainly trying to make 15 sure that the process would be effective for any of 16 the non-LWRs that we're aware of and that industry 17 may be looking to try to tabletop or possibly pilot 18 some of these activities with designs other than 19 HTGRs where it's been mostly tested in the past.
20 MEMBER REMPE: Yes, I know that there's 21 been an effort to try and group like sodium-cooled 22 reactors --
23 MS. CUBBAGE: Yes.
24 MEMBER REMPE: -- and gas reactors, 25 because there's a difference between pebbles --
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25 1 MS. CUBBAGE: Right.
2 MEMBER REMPE: -- and prismatics. But 3 on the other hand, when you try and do licensing basis 4 events, it seems like you're going to have to do a 5 concept specific. So I'm just kind of wondering how 6 you deal with that.
7 MS. CUBBAGE: Well, we're focusing on the 8 process now --
9 MEMBER REMPE: Okay.
10 MS. CUBBAGE: -- which is a technology 11 inclusive process. Until we actually have an 12 applicant for a specific design that needs to run 13 through the process, we'd be focusing on technology 14 inclusive today.
15 MEMBER REMPE: Thanks.
16 MEMBER CORRADINI: So, Amy, don't go 17 anywhere. Sorry.
18 MS. CUBBAGE: That's okay.
19 MEMBER CORRADINI: So, I mean, to do this 20 in some fashion, are you picking a couple of pilots?
21 So, you know, what I'm trying to get at is --
22 MS. CUBBAGE: Yes.
23 MEMBER CORRADINI: -- I understand that 24 you want to make it inclusive.
25 MS. CUBBAGE: Right.
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26 1 MEMBER CORRADINI: But in some sense, it 2 all gets down to the, what I think where Joy's going, 3 it eventually gets down to specifics.
4 MS. CUBBAGE: Right.
5 MEMBER CORRADINI: So have you taken a 6 couple of pilots to see?
7 MS. CUBBAGE: So where the rubber meets 8 the road is ultimately applying this to a technology.
9 And at this point, we can't drive that because, you 10 know, we need an applicant to really --
11 MEMBER CORRADINI: Okay.
12 MS. CUBBAGE: -- fully drive the process.
13 But I think industry, Amir Afzali is here 14 from -- he may be able to speak to this. But they 15 are looking at opportunities to try to pilot with 16 some of the designs that are more maturely developed, 17 for example, the prism reactor where we had already 18 done a preliminary design review back in the '90s.
19 And certainly it's already been somewhat tested out 20 on NGNP and other projects of that nature.
21 MEMBER REMPE: And you can do that. But 22 then if nobody wants to build it, is that the one to 23 prioritize? I mean, if you don't have, you know, if 24 there's no one saying, hey, I'm getting ready to do 25 this --
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27 1 MS. CUBBAGE: Well, I mean, it's the 2 chicken and egg.
3 MEMBER REMPE: Yes.
4 MS. CUBBAGE: You need to test it on what 5 you know, or you have to wait until somebody comes 6 forward with an application and applies it.
7 MEMBER CORRADINI: So, sorry.
8 MEMBER REMPE: Okay.
9 MEMBER CORRADINI: So I'm aware that DOE 10 has development plans in four generic areas.
11 MS. CUBBAGE: Yes.
12 MEMBER CORRADINI: And then they have 13 some sort of, we'll call it leading candidate design 14 in the four generic areas. Is it really to the 15 industry and DOE to kind of give you some examples to 16 work on? That's what --
17 MS. CUBBAGE: That would be great. But, 18 you know --
19 MEMBER CORRADINI: Okay.
20 MS. CUBBAGE: We discussed that at our 21 last public meeting that it will be helpful to have 22 some designs to pilot and work through these issues 23 with. But it's yet to be determined --
24 MEMBER CORRADINI: Okay.
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28 1 forward.
2 MEMBER CORRADINI: Thank you.
3 MR. SCHULTZ: John, before you leave this 4 slide, since Strategy 4 feeds into Strategies 3 and 5 5, what is the staff's involvement right now in 6 Strategy 4 in going forward?
7 MR. SEGALA: So we have people that are 8 involved in the ASME Section 3, Division 5 9 activities. We're currently waiting for the NEI 10 technology working groups through ASME to instruct us 11 on whether we should move forward and endorse the 12 2017 edition of ASME Section 3, Division. 5. If we 13 get that, we will move forward pretty heavily over 14 the next two years or so and go down an endorsement 15 process.
16 In ANS, well, I think also in ASME is the 17 non-light water reactor PRA standard. And we have 18 some people on that committee. And then on the ANS 19 standards, Jan and some other people are members of 20 the various subcommittees on non-light water 21 reactors.
22 MR. SCHULTZ: Thank you.
23 MR. SEGALA: Okay. So this slide will 24 be really quick. These are the dates for when we 25 previously met with you all on the near-term NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 1 implementation action plans and the draft guide on 2 the design criteria. So next slide.
3 So the top part is today's meeting on the 4 Reg Guide 1.232. And then we plan to come back in 5 March for the full committee meeting. And we're 6 hopeful that we can get a clean letter so that we can 7 move forward and issue the final Reg Guide.
8 The bottom three bullets are the other 9 yellow boxes that I highlighted in the previous 10 slide. We're planning to come talk to you on 11 functional containment in a couple weeks and then 12 come back in April for the full committee meeting.
13 For licensing modernization project, we 14 listed two subcommittee meetings there because we 15 wanted to have opportunities to get your input early 16 in the process. So we haven't, we wanted to map out 17 the opportunity to have your involvement twice during 18 the development of the draft guide.
19 And then the December full committee 20 meeting is just a planning wedge to come back with 21 the final guide.
22 EP rule, the plan is to provide the draft 23 proposed rule to you a month before the August 22nd 24 meeting and then follow that up in October with the 25 full committee meeting.
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30 1 So, with that, I'll turn it over to Jan.
2 MS. MAZZA: Thank you, John. So I'm 3 going to talk a little bit of some background and 4 summary of the Reg Guide up to now before we get into 5 the specific ACRS letter comments.
6 So this slide shows the recent progress 7 on the Reg Guide. Back last February we issued Draft 8 Guide-1330 for the 60-day public comment period. And 9 then we had a public meeting in August of 2017 for 10 additional staff interaction with the public on 11 specific issues in order to finalize the Draft Reg 12 Guide 1.232.
13 We continued the discussions in November 14 on two specific areas, ARDC 17 and 26, which are 15 electric power systems and reactivity control 16 systems.
17 And then in January of this year, we 18 issued the Draft Final Reg Guide 1.232 and then Draft 19 Public Comment Resolution Table ahead of this meeting 20 today. And we are hoping to issue the final Reg 21 Guide in March of this year.
22 So now I'm going to go through some 23 slides you've already seen before, but just go 24 through the background of the Reg Guide and what the 25 purpose is.
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31 1 So in 2013 the NRC and DOE agreed to 2 pursue an initiative to provide guidance to non-light 3 water reactor designers for developing principal 4 design criteria. The idea was to establish design 5 criteria for non-light water reactors similar to the 6 light water reactor focused general design criteria 7 in 10 CFR 50 Appendix A.
8 Non-light water reactor designers could 9 then use these design criteria to develop the 10 principal design criteria for their facilities.
11 The regulations in 10 CFR 50 Appendix A 12 state that general design criteria establish minimum 13 requirements for the principal design criteria for 14 water-cooled nuclear power plants and are generally 15 applicable to non-light water reactors.
16 And then the contents of application, 17 technical information sections of 10 CFR 50 and 52 18 state that applications must include principal design 19 criteria for their facility based on the general 20 design criteria.
21 So, as mentioned on the last slide, the 22 principal design criteria are derived from the 23 general design criteria in 10 CFR 50 Appendix A, which 24 establishes the applicability of the general design 25 criteria to both light water reactors and non-light NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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32 1 water reactor designs.
2 And so, on this slide, we have an excerpt 3 from 10 CFR 50 Appendix A. And the first part in 4 black speaks to the light water reactors. And then 5 the red on the bottom speaks to the non-light water 6 reactors.
7 It says the general design criteria are 8 also considered to be generally applicable to other 9 types of nuclear power units and are intended to 10 provide guidance in establishing principal design 11 criteria for such other units.
12 So the language in 10 CFR 50 Appendix A 13 indicates that the general design criteria are 14 guidance for non-light water reactors. And as such, 15 non-light water reactor applicants would not need to 16 request an exemption from the general design criteria 17 when proposing their principal design criteria for 18 their specific design.
19 So this Reg Guide provides the additional 20 guidance for reactor designers and applicants of non-21 light water reactor designs for developing a 22 principal design criteria.
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33 1 for its facility based on the design using the general 2 design criteria, non-light water reactor design 3 criteria, or other design or technology specific 4 criteria as needed.
5 So, for instance, a fluoride high 6 temperature reactor uses, say, the TRISO fuel similar 7 to modular high temperature gas reactors. So, when 8 they develop their principal design criteria, they 9 may use some of the advanced reactor design criteria 10 for some things and then maybe a modular high 11 temperature gas reactor design criteria for others.
12 So it provides flexibility.
13 Applicants also must consider the public 14 safety --
15 CHAIRMAN BLEY: Can I interrupt you, Jan 16 --
17 MS. MAZZA: Um-hmm.
18 CHAIRMAN BLEY: -- because what you just 19 said makes sense? But when I read the Reg Guide, and 20 I guess what you say in there was a matter of intent.
21 I was thinking you have, you now have two sets of 22 sort of design specific, at least concept specific 23 design criteria that people with those kinds of 24 reactors we'd expect them to follow.
25 But we also have the more general ARDCs.
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34 1 And I was thinking, well, what do they apply to? You 2 know, are they just the straw man that you then adapt, 3 which is kind of what you just said?
4 But the words in here I thought said that 5 you and DOE, who helped in this development, thought 6 that for four designs, the lead fast reactors, gas-7 cooled reactors, fluoride high temperature reactors, 8 and molten salt reactors, the ARDC would apply as is.
9 But you're just saying maybe not.
10 MS. MAZZA: Well, yes --
11 CHAIRMAN BLEY: And that seems 12 reasonable --
13 MS. MAZZA: But --
14 CHAIRMAN BLEY: -- maybe not.
15 MS. MAZZA: It's a guidance document.
16 It provides flexibility. It just gives applicants 17 an idea of how the staff thinks that the general 18 design criteria could be adapted to the non-light 19 water reactor design criteria.
20 CHAIRMAN BLEY: Okay. Thanks.
21 MS. MAZZA: So also, applicants are 22 responsible for considering the public safety matters 23 and fundamental concepts, such as defense-in-depth, 24 in the design of their specific facility and for 25 identifying and satisfying necessary safety NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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35 1 requirements, also to provide the principal design 2 criteria for the design and supporting information 3 that justifies how the design meets the principal 4 design criteria submitted, and how the principal 5 design criteria demonstrate adequate assurance of 6 safety.
7 And then in instances where a general 8 design criteria or a non-light water reactor design 9 criteria is not proposed, the designer or applicant 10 must provide a basis and justify the omission from a 11 safety perspective.
12 MEMBER SKILLMAN: Jan, let me ask you to 13 go back a slide, please. Back one more. The 14 boldened would not need to request an exemption.
15 Would you describe to us what discussion occurred 16 among the staff to, if you will justify that idea?
17 MS. MAZZA: Well, we basically discussed 18 it with our general counsel. And they were in 19 agreement that that, since the design criteria, the 20 general design criteria are requirements for light 21 water reactors and are generally applicable and 22 guidance for non-light water reactors, therefore, 23 they would not need to follow the general design 24 criteria in Appendix A. Non-light water reactors 25 would not need to follow that word for word just like, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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36 1 as the light water reactors are required to today.
2 MEMBER CORRADINI: I'm with him. I'm 3 confused.
4 MEMBER SKILLMAN: Well, let me explain 5 why I asked the question. I can understand the 6 desire to not have an exemption. That takes a huge 7 amount of administrative burden off the table.
8 On the other hand, the effort to create 9 what would either be the basis or justification for 10 an exemption would exemplify the degree to which the 11 NSSS designer and the staff considered the 12 consequence of what it is that might have been in the 13 exemption.
14 It just seems to me that there are a 15 number of very basic concepts that we hold to in our 16 industry that have kept us safe for a long time. And 17 I can understand a novel design wanting an exemption 18 because their specific design doesn't fully meet at 19 least what I would think is the intent of the general 20 design criteria.
21 But the effort to justify what might 22 conceivably be an exemption explores perhaps 23 unintended consequence. And to me that's the value.
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37 1 men and women look at the whatever it is that's 2 different and give real consideration to why that is 3 acceptable.
4 And so I'm just curious. Was this just 5 an added phrase where counsel said, yes, write that 6 and that way they don't have to do a lot of work? Or 7 was there consideration to the greater effort that 8 would truly provide the NSSS designer and the Agency 9 basis to say, even though that's different, that's 10 okay?
11 MS. MAZZA: So, once again, non-light 12 water reactor applicants would have to submit their 13 principal design criteria. And that would be subject 14 to staff review. And, you know, all of those aspects 15 would be part of that review, you know, even though 16 it wouldn't be a specific exemption.
17 And I think Amy has something --
18 MS. CUBBAGE: Yes, this is Amy Cubbage.
19 This really has nothing to do about the burden of an 20 exemption or not. It's basically saying that a non-21 LWR applicant cannot use these blindly. They have 22 to develop a whole set of PDCs. And, you know, the 23 issue of an exemption or not is because these don't 24 apply.
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38 1 they submit an exemption request or not, they still 2 have to provide justification for why these are 3 appropriate.
4 MS. CUBBAGE: Right. So all the 5 technical work needs to be done to justify why their 6 principal design criteria are sufficient and 7 appropriate for their design.
8 MR. SEGALA: And I think also we have to 9 live within the regulations. We can't require 10 something of an applicant that the regulations don't 11 support.
12 So, you know, but we need to make sure 13 that the design is safe and that they have the right 14 principal design criteria and that they adequately 15 justify that.
16 And there will be lots of discussions and 17 documentation of why that particular PDC is 18 appropriate for that design and whether they missed 19 anything, you know, because they can't just blindly 20 apply the ARDCs or the SFRDCs to their design and say 21 I'm an SFR, therefore I'm only giving you the SFRDCs.
22 They need to look broader than that and 23 say are there any unique aspects of my SFR that needs 24 additional principal design criteria that wasn't 25 envisioned when we developed the Regulatory Guide.
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39 1 MEMBER KIRCHNER: So may I jump in, Dick?
2 MEMBER SKILLMAN: I want to thank John 3 and Jan and Amy.
4 MS. MAZZA: Okay.
5 MEMBER SKILLMAN: I'm satisfied very 6 well.
7 MS. CUBBAGE: Great. Thank you.
8 MEMBER KIRCHNER: So this is the danger 9 of coming back to the committee. You gave us quite 10 a few months to churn on this material.
11 So, John, to follow up what you just 12 said, the more I think about it, the more I would 13 expect that you would develop advanced reactor design 14 criteria. And you've, many times now the staff has 15 come in front of us to say we're trying to be 16 technology neutral. We're going more to performance-17 based and such. And fine, I agree with that.
18 What I sense -- and I know you 19 collaborated with the DOE on this, and a tremendous 20 amount of work has been put into this. But basically 21 what I sense is for the HTGR and the sodium fast 22 reactors you kind of, I wouldn't say you've fallen 23 into a trap per se. But you've almost developed the 24 PDCs for specific designs or at least broad outlines 25 for the PDCs. That's what the GDCs do.
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40 1 But it presumes -- there's too much in my 2 opinion presumption of design choices and results in 3 both of those specific, reactor specific types, Jan.
4 And I wonder if you're not better served 5 to fall back on your basic principles for general 6 design criteria and just stick with the advanced, and 7 we can talk about the details of those, as the 8 template. And then have the Department or the 9 applicant jointly come in and propose what they want, 10 because I see in many places you're presuming the 11 design. What if the high temperature gas-cooled 12 reactor turns out to be a fast reactor and it doesn't 13 have particle fuel, right?
14 So then -- and what it's forced you into 15 in your containment, functional containment paper is 16 the multiple, is to come up with multiple definitions 17 of containment for each reactor. And it seems to be 18 philosophically what you want is to define what the 19 function of the containment is in a very, in a 20 functional sense.
21 So I'm with you where you're going, but 22 not get -- at least the NRC, the applicant and the 23 DOE is a different matter -- get trapped into 24 endorsing, if you will, expected outcomes when you 25 don't have the design yet, you don't have the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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41 1 qualified fuel, you don't have sufficient detail to 2 say that this adaptation of our basic principles is 3 warranted.
4 Do you see where I'm going? It's a 5 philosophical point. And I know you've put a lot of 6 work in. It's rather late, a year later, to bring 7 something like this up. But --
8 MS. MAZZA: Well --
9 MEMBER KIRCHNER: -- I was struck that 10 the advanced criteria as a whole were pretty good.
11 So I'm not throwing, I'm not trying to throw a wet 12 blanket on everything. Why wouldn't you stand by 13 that, and then let the applicant come in and modify?
14 MS. MAZZA: Well, again, this is a 15 guidance document. And so I think it's helpful to 16 the modular high temperature gas reactor community 17 and the sodium fast reactor community to see where we 18 would, what we would agree with and not agree with in 19 the design criteria.
20 And again, it's, each applicant's going 21 to have to come in and propose their own principal 22 design criteria.
23 This is just, this is where staff is.
24 This is what staff was thinking when they looked at, 25 you know, the SFR designs that are out there. And, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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42 1 you know, here's how we think, you know, our general 2 design criteria could be adapted to that.
3 And so I think that's helpful to 4 designers out there. And, you know, we've gotten 5 good feedback from that, too. So --
6 CHAIRMAN BLEY: Jan, following up on 7 Walt's point, maybe, you know, deciding to keep them, 8 which I expect you're going to do --
9 MEMBER KIRCHNER: Yes, I'm not saying 10 throw them out by the way.
11 CHAIRMAN BLEY: -- some definition of 12 what's involved in the design that led you to that 13 that's attached to the paper might be very helpful, 14 not just for now but for when something that doesn't 15 quite fit that comes in and it helps you explain why 16 you don't think their, they've come up with the right 17 principal design criteria.
18 MR. SEGALA: And I'd like to add, I mean, 19 I can't think of a specific example. Maybe Jan can.
20 But I think, and what we got from DOE and 21 then what we ended up with, there are a lot of 22 circumstances where we proposed things more general 23 because we were trying to think outside the box and 24 say, well, there could be a design that has active 25 cooling so we need to have this extra GDC or PDC in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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43 1 there that maybe DOE didn't have in their original 2 submittal.
3 So I think a lot of the disagreements and 4 maybe some of the public comments and how we resolve 5 them, we kept some PDCs in the Reg Guide that maybe 6 industry felt that shouldn't be in there because 7 we're trying to, well, what if a design comes in with 8 that. We still need to have these design criteria 9 there. So --
10 MR. SCHMIDT: Yes, this --
11 CHAIRMAN BLEY: I didn't say it before.
12 But your rationale on each one of these gives a lot 13 of helpful information.
14 MR. SCHMIDT: Yes, this is Jeff Schmidt 15 from the staff.
16 So I can think of one example, while you 17 were speaking, of where we diverge from the DOE. DOE 18 wanted to basically say residual heat removal and 19 ECCS were the same function and could be rolled into 20 one ARDC, ARDC 34.
21 And the staff was hesitant because we 22 were concerned that some design could come in and 23 still require injection. And we thought the way the 24 current DOE was structured would preclude that.
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44 1 it is a fair statement to say that the modular high 2 temperature section, the sodium have some concept of 3 a design inherent in them that we were more familiar 4 with so we felt probably more comfortable in breaking 5 those out. And I think that's a fair statement.
6 MR. SCHULTZ: I think that makes sense.
7 But here you have a general comment that suggests 8 that, it gives a suggestion that in staff's review of 9 an application, if the applicant is following 10 something that is a proposed PDC derived from the 11 GDCs, then exemption isn't going to happen. And I 12 think that's too general a statement.
13 The specific application is going to 14 determine what the staff needs to do and whether an 15 exception is going to come into the picture. I think 16 a general statement like this is, in fact, 17 misleading, because what you're derived from can be 18 very, interpreted as very broad for an applicant that 19 deals. They've derived their overall PDC approach 20 from the GDC. And so they're free and clear with 21 regard to moving forward --
22 MR. SEGALA: I think --
23 MR. SCHULTZ: -- staff moving forward to 24 an exemption.
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45 1 just tied to whether they use light water for the 2 coolant or they don't. And if they don't, they 3 don't, the GDCs themselves don't, they don't have to 4 meet those. And therefore, they don't need to have, 5 to submit an exemption for something that they don't 6 have to comply with.
7 MR. SCHULTZ: So that's another way to 8 read the words --
9 MR. SEGALA: I mean, that's --
10 MR. SCHULTZ: -- in applying the staff -
11 -
12 MR. SEGALA: -- that's the legal kind of 13 interpretation is, you know, just looking at the 14 words.
15 But they're still going to need to go 16 through an analysis and justify that they have the 17 appropriate design criteria for that design and have 18 a basis for that. And then we're going to, the 19 staff's going to challenge them on each one of those 20 and make sure that we agree and that there's not 21 something missing that should be there.
22 MR. SCHULTZ: Thank you.
23 MS. MAZZA: So we received an ACRS letter 24 in March of 2017. And the items you see on the slide 25 here are basically what the comments were. We're NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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46 1 going to go through these today.
2 So it was technology-specific licensing 3 basis events, facilitating PRA in the design 4 criteria, reactor fuel design limits, specifically 5 MHTGR-DC 10, containment, which covered all three 6 design criteria, electric power systems, which is 7 ARDC 17, and then reactivity control systems, which 8 is ARDC 26.
9 So, before we begin the discussion on the 10 ACRS comments, we were requested to provide a summary 11 of the topics presented in 2017 for the Future Plant 12 Design Subcommittee meeting. All four of the topics 13 on this slide were the subject of comments in the 14 March 21st letter. And we're going to be discussing 15 these further today.
16 In the interest of time, if you wouldn't 17 mind me just flipping through this --
18 CHAIRMAN BLEY: Yes, that's fine.
19 MS. MAZZA: -- since we're going to be 20 going through those.
21 So the next thing I want to talk about is 22 the interface between the Vision and Strategy 23 Activities 3 and 5. As John showed you before, the 24 staff is focused on resources, focusing our resources 25 on Strategies 3 and 5 and specifically in the areas NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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47 1 highlighted in yellow on the slide.
2 And as we gain more insight into these 3 topics, it's become apparent that they are closely 4 related. The LMP includes a series of white papers 5 that we talked before about. And then under Strategy 6 5, we have the EP for SMRs and other new technologies 7 and then the functional containment performance 8 criteria. And as John mentioned, we have near-term 9 interactions on all those.
10 So this brings me to the first ACRS 11 comment. This comment was included in the Vision and 12 Strategy portion of the ACRS letter. However, it was 13 mentioned several times during our discussions. So 14 we decided to include it as part of this presentation.
15 So the comment was, Strategy 3, 16 Contributing Activity 3.2, which develops approaches 17 to licensing bases and will determine licensing bases 18 for non-light water reactor technologies, is 19 particularly important to implement early on.
20 Identification of technology-specific licensing 21 basis events need to be developed to ensure that the 22 associated design criteria are complete.
23 So the staff agrees with this comment and 24 understands the importance of defining the 25 technology-specific licensing basis events. As NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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48 1 mentioned on the previous slide, we're participating 2 in the industry led LMP. And the licensing basis 3 event methodology was outlined in the LBE white 4 paper.
5 And this was the first paper submitted to 6 the NRC for review. And we will be discussing this 7 with the ACRS in June and October of this year.
8 So another ACRS comment was, it would be 9 useful to ensure that the language of the ARDCs 10 facilitate or at least does not preclude the use of 11 probabilistic risk assessment, especially in the 12 areas where graded compliance is suggested.
13 So the staff doesn't believe that the 14 ARDCs as written would preclude the use of the PRA.
15 The PRA and other licensing modernization project 16 products will establish the design basis events. And 17 then the design basis events will be used to determine 18 the set of safety-related SSCs required for design 19 basis accidents, as well as the graded approach to 20 determine the special treatment of SSCs for other 21 event categories.
22 So the ARDC and the LMP products can then 23 inform what the design specific principal design 24 criteria should be. And this is an iterative process 25 that ensures safety and supports the need for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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49 1 integrated plant safety analysis.
2 So the next slide shows the ACRS comment 3 regarding the use of specified acceptable system 4 radionuclide release design limits in place of a 5 specified acceptable fuel limits for modular high 6 temperature gas reactors and perhaps other 7 technologies such as molten salt reactors.
8 So the comment reads, MHTGR Design 9 Criteria 10, as presently written, is cryptic. The 10 phrase, specified acceptable system radionuclide 11 release design limits, SARRDL, needs to be clearly 12 defined.
13 Replacing the GDC specific, specified 14 acceptable fuel design limit, SAFDL, concept with the 15 proposed SARRDL concept in the ARDCs is acceptable.
16 However, during design, reactor designers will need 17 to develop their own design specific limits in order 18 to characterize and evaluate their own design.
19 The new SARRDL concept requires 20 additional analysis that the staff will have to 21 review and approve. Later during operation, 22 licensees will monitor both circulating activity and 23 plate-out activity to ensure acceptable fuel 24 performance, that is as evidence that the SARRDLs are 25 being met.
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50 1 So, again, the staff agrees with this 2 comment. And so we note that the definition of 3 SARRDL depends on several factors, including 4 mechanistic source term, licensing basis events, and 5 then the functional containment performance criteria.
6 Reactor designers will need to consider 7 all of these collectively in order to define the 8 design specific SARRDL that will meet the 9 requirements. And the functional containment 10 performance criteria SECY paper will discuss topics 11 integral to the functional containment like the 12 SARRDLs.
13 And again staff is scheduled to discuss 14 this with ACRS on the 22nd of this month.
15 MEMBER KIRCHNER: So may I interrupt?
16 MS. MAZZA: Sure.
17 MEMBER KIRCHNER: Do you really need this 18 SARRDL? Are you introducing problems?
19 I've worked with this technology. I 20 understand its robustness and benefits. I'm trying 21 to sort out why you wouldn't just stick with the, 22 terrible acronym, SAFDL instead of SARRDL and then 23 proceed to analyze your reactor coolant system and 24 your functional containment to ensure that, if you 25 were using performance-based EPZ and performance-NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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51 1 based containment that the off-site doses are 2 acceptable and such. I'm just struggling what does 3 this SARRDL concept buy you.
4 MR. SCHMIDT: This is Jeff Schmidt from 5 the staff. What we were -- so, in my sense, the 6 TRISO-based fuel can degrade under most expected 7 conditions rather gracefully.
8 MEMBER KIRCHNER: Right.
9 MR. SCHMIDT: Right. And so what we were 10 trying to move away from, the SAFDL has kind of a 11 concept of, if you hit certain criteria, that you 12 would basically fail to fuel in a complete fashion.
13 In other words, you'd lose the integrity of the clad.
14 MEMBER KIRCHNER: You'll do the same with 15 TRISO fuel if you get it hot enough.
16 MR. SCHMIDT: You're correct. You're 17 right. You would. But I think the issue is the 18 margin to those points are farther away in general 19 than, say, for the light water reactor.
20 MEMBER KIRCHNER: You don't know that.
21 You haven't had the design submitted yet. This is 22 to my philosophical problem.
23 MR. SCHMIDT: Right. This assumes 24 something.
25 MEMBER KIRCHNER: You're adapting in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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52 1 advance to something you expect.
2 MR. SCHMIDT: Yes.
3 MEMBER KIRCHNER: But you don't have it 4 yet.
5 MR. SCHMIDT: That's correct.
6 MEMBER KIRCHNER: So I would be more 7 comfortable sticking with your existing definition 8 for fuel design limits and then let the applicant and 9 the Department make their case. And I think they can 10 make a case.
11 So I'm not, again, being an 12 obstructionist. But I do think you're introducing a 13 complexity and you're building in advanced design 14 expectations and performance expectations that need 15 to be demonstrated.
16 MR. SCHMIDT: I think --
17 MEMBER KIRCHNER: All fuel leaks.
18 MR. SCHMIDT: I think that's true, yes.
19 MEMBER KIRCHNER: Right?
20 MR. SCHMIDT: I agree. But --
21 MEMBER KIRCHNER: So you have leaky fuel.
22 You have circulating activity in PWRs.
23 MR. SCHMIDT: Sure.
24 MEMBER KIRCHNER: Or BWRs.
25 MR. SCHMIDT: Sure. I think this is --
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53 1 MEMBER KIRCHNER: It should be lower.
2 MR. SCHMIDT: -- trying to move more --
3 MEMBER KIRCHNER: What you're doing 4 backhandedly is saying there's a QA requirement on 5 this fuel that limits the amount of circulating 6 inventory.
7 MR. SCHMIDT: Right.
8 MEMBER KIRCHNER: But that's a design 9 detail. I mean, there should be quality fuel in any 10 reactor, I mean, we'd hope.
11 But I wonder how much you're gaining with 12 doing this, because, just as Jan said earlier, you 13 know, hanging out there is functional containment.
14 And that's going to interact with this.
15 So, if you're going to a performance-16 based containment during the accident sequences, this 17 is where PRA will help, and you go through all this, 18 you're going to back through the system just like you 19 do with conventional reactors now. You're going to 20 go from fuel to reactor coolant boundary to 21 functional containment. So I don't see exactly what 22 this is buying you at this point.
23 MR. SCHMIDT: You know, the --
24 MEMBER KIRCHNER: It's just a 25 philosophical observation.
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54 1 MR. SCHMIDT: So, if you turn the coin 2 on the other side --
3 MEMBER KIRCHNER: Right.
4 MR. SCHMIDT: -- you can kind of argue 5 that SAFDL is artificial, right?
6 MEMBER KIRCHNER: Of course, yes.
7 MR. SCHMIDT: I mean, so it's --
8 MEMBER KIRCHNER: There's no one point.
9 MR. SCHMIDT: Right, it's an overly 10 conservative construct we've created to protect 11 effectively dose, right?
12 MEMBER KIRCHNER: Right.
13 MR. SCHMIDT: So we're trying to move it 14 to the more performance-based dose aspect. And 15 you're right. It's a function of the other barriers 16 and the transport of those that will -- it kind of 17 goes along with the frequency consequence curve 18 concept --
19 MEMBER KIRCHNER: Right.
20 MR. SCHMIDT: -- where the criteria in 21 that construct is the dose to the public, right, or 22 the dose at the boundary.
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55 1 gas reactors.
2 MEMBER KIRCHNER: Yes.
3 MR. SCHMIDT: But there are other designs 4 where I'm going to have no SAFDL, right, a liquid 5 fuel design --
6 MEMBER KIRCHNER: Let's put liquid fuel 7 --
8 MR. SCHMIDT: Right, I understand.
9 MEMBER KIRCHNER: -- in a different 10 category because --
11 MR. SCHMIDT: But, I mean, the concept.
12 MEMBER KIRCHNER: -- a liquid fuel 13 reactor's normal operating state is the worst 14 nightmare for any other reactor design. You've got 15 the fission product inventory circulating. So let's 16 leave the liquid fuel things out -- they have been 17 dropped over the years for good reason -- and come 18 back to this.
19 That was a statement. I guess --
20 (Laughter.)
21 MEMBER CORRADINI: Just then as a 22 personal opinion.
23 MEMBER KIRCHNER: A personal opinion.
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56 1 the problems they had with it.
2 But coming back to this, and let me stay 3 on point, that I think the SAFDL would work, because 4 I've worked with this technology and I've designed 5 and built the reactor.
6 So you're going to, the designer is going 7 to set a limit, a temperature limit, just like your 8 2200 for LWRs fuel because they are going to want 9 comfortable margin before that point where the TRISO 10 particles shows substantial degradation.
11 So, when you design this reactor, the 12 designer is going to come in and say my peak 13 temperature under all the accident sequences, it's 14 passably safe, all that.
15 He's going to design it or she such that 16 the peak temperature, with an uncertainty and 17 numerous calculations, gives him or her confidence 18 that they're not challenging the breakpoint on the 19 TRISO particle fuel performance such that you have 20 significant deterioration and release into the 21 primary coolant system.
22 So it's really in a -- again, I'm being 23 philosophical. But in a design sense, it's really 24 no different than an LWR. Now, the fuel may be much 25 more robust. And we're not going to argue that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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57 1 today. But from a designer's approach, that's what 2 you really will do.
3 And you'll look at that MHTGR in a 4 passive cool-down mode. And you know what, that 5 temperature you pick so that you have margin 6 determines the diameter of the vessel and the size of 7 the core.
8 MR. SCHMIDT: Right.
9 MEMBER KIRCHNER: So I kind of get where 10 the applicant and the Department may be coming from.
11 But from you, as a regulator, I think the SAFDL 12 concept works.
13 MEMBER REMPE: Well, are you assuming 14 prismatic fuel in your comments?
15 MEMBER KIRCHNER: No.
16 MEMBER REMPE: You're considering both 17 pebble --
18 MEMBER KIRCHNER: It could be pebbles.
19 It could be prismatic. It could be --
20 MEMBER REMPE: And then didn't we spend 21 also last time a lot of time talking about it's time 22 at temperature. It's not just a temperature --
23 MEMBER KIRCHNER: Time at temperature is 24 another --
25 MEMBER REMPE: Yes.
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58 1 MEMBER KIRCHNER: -- issue. So you need 2 to go through that analysis.
3 But again, at least for the concepts, 4 because you're writing things -- see, this is what I 5 was philosophically objecting to earlier. You're 6 assuming something about the design, and then you're 7 writing the GDCs to fit the design.
8 Yes, a gas-cooled reactor is different 9 than an LWR. But this is an example where I don't 10 think you need to go there.
11 MR. SCHMIDT: One aspect I think we do 12 pick up, though, is the concept of, what I was 13 thinking was under an AOO you might have additional 14 leakage or bypass from a TRISO fuel particle where we 15 would not necessarily allow that in an LWR fuel, 16 right.
17 So, you know, LWR SAFDL concept is kind 18 of a binary concept. You either fail or don't fail, 19 right. And this, one of the things was, as you heat 20 up and you have additional, say, leakage from the 21 TRISO fuel, this would allow that concept to occur 22 and kind of it goes with the frequency consequence 23 curve where it's kind of a continuum instead of a 24 binary change --
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59 1 there's time at temperature as well is a factor in a 2 lot of these scenarios that you'll analyze.
3 But I still submit even for an AOO you 4 will, as a designer, you'll do the same thing.
5 You'll pick a temperature limit that you think you 6 can withstand for the length of the transient.
7 That's what you'll design to.
8 MR. SCHMIDT: But we're kind of allowing 9 some potential additional radionuclide and dose with 10 this concept where the SAFDL would not, right. So 11 it's more of a continuum again.
12 So, if you look at the frequency 13 consequence curve, you know, you would say, okay, 14 well, I have this fuel. It's doing most of the 15 containment, confinement, whatever word you want to 16 --
17 MEMBER KIRCHNER: Right.
18 MR. SCHMIDT: -- you know, use.
19 MEMBER KIRCHNER: It's the primary 20 barrier.
21 MR. SCHMIDT: Yes, it's the primary 22 barrier. Thank you.
23 MEMBER KIRCHNER: Sounds like LWR fuel, 24 doesn't it?
25 MR. SCHMIDT: Yes, it does.
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60 1 MEMBER KIRCHNER: Yes.
2 MR. SCHMIDT: It does to a certain 3 degree. But I think in LWR space, though, the other 4 barriers probably are equally important, especially 5 for, in accident scenarios, right --
6 MEMBER KIRCHNER: I already submitted 7 that this is probably a more robust --
8 MR. SCHMIDT: Right.
9 MEMBER KIRCHNER: -- fuel form. That's 10 to be demonstrated, but it probably is.
11 So I just feel, as somebody who's going 12 to approach the design, yes, okay, but it's a 13 complication that then takes you into several steps.
14 You're mixing a bunch of things together.
15 MEMBER CORRADINI: So can I ask Walt's 16 question a different way, because I'm listening to 17 you guys go back and forth and I'm not sure where I, 18 where it stands?
19 Is there something unique about the 20 particular design you thought about as you developed 21 this that makes this necessary? Or is this just your 22 evolving -- the way you argued back with Walt or 23 discussed with Walt was, well, this is a natural 24 evolution. And it could be applied to light water 25 reactor fuel. That's what I thought you said.
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61 1 MR. SCHMIDT: Right, you could.
2 MEMBER CORRADINI: Or is it more that 3 there's something particular about a particular MHTGR 4 design that requires this? That's what is the only 5 thing, it kind of goes back to your starting point, 6 which is they were thinking of something --
7 MEMBER KIRCHNER: Yes.
8 MEMBER CORRADINI: -- when they wrote 9 this down.
10 MEMBER KIRCHNER: Well, you're always 11 going to have leakage with the TRISO fuel. You'll 12 have defects. The challenge is obviously to have a 13 very high quality fuel with very low leakage.
14 And so it is, as Jeff was saying, there 15 is something of a gradation that is a little bit 16 different than an LWR fuel performance where you 17 maybe get -- but even LWR fuel, although the quality 18 has improved drastically, you do get leakage. And 19 you do get circulating inventory.
20 So I just struggled with this when I went 21 back again. Like I said, you gave us too much time 22 and material.
23 So I just, now maybe the proponents have 24 much more, I'm not asking to hear it, sophisticated 25 set of arguments for this versus using, sticking with NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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62 1 the acceptable fuel design limits.
2 CHAIRMAN BLEY: I think we've worked this 3 through.
4 MEMBER KIRCHNER: I made my point.
5 CHAIRMAN BLEY: And we need to march 6 ahead if we're going to get done. We'll probably 7 stay an extra half hour till about 12:30 to finish 8 up, but don't count on that.
9 MS. MAZZA: Okay.
10 CHAIRMAN BLEY: Keep trying to catch up.
11 There's a long way to go.
12 MS. MAZZA: All right. So we're going 13 to skip containment for now because our presenter is 14 not here yet. So we're going to go into number or 15 to reactivity control systems since Jeff's sitting 16 here. And then we'll do electric power systems. So 17 this is Jeff's.
18 MR. SCHMIDT: Okay. This is Jeff 19 Schmidt from the staff.
20 I'm going to talk about ARDC 26. So ARDC 21 26 eliminated the GDC requirement for controlling the 22 rate of reactivity changes resulted from planned, 23 normal power changes. For harder spectrum reactors, 24 particularly liquid fuel systems, the control of the 25 rate of reactivity insertion can be very important NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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63 1 and should be retained.
2 So that was the ACRS comment on the first 3 re-write of ARDC 26.
4 MEMBER CORRADINI: So can I ask? Well, 5 can I go to GDC 26? And I'm still in a learning 6 mode. Is this normal operation for GDC 26?
7 MR. SCHMIDT: Okay. So this is, there's 8 very --
9 MEMBER CORRADINI: This affects other 10 things. So --
11 MR. SCHMIDT: Well, there's very clever 12 wording in GDC 26.
13 MEMBER CORRADINI: Clearly.
14 MR. SCHMIDT: So it's not, you know, 15 normally we would call it normal operation. But the 16 writers of GDC 26, in my opinion, were very careful.
17 They said, they didn't use the word normal operation.
18 They used planned, normal power changes, which, in my 19 opinion, means normal plant operations day to day.
20 So that's a very important distinction in 21 my mind, because a lot of times people will argue 22 normal operations includes AOOs. So it's the upset 23 condition and what you do day to day.
24 So I think that the original writers of 25 GDC 26 didn't want to use normal operations because NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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64 1 it could imply AOOs, the upset condition. So they 2 used planned, normal power changes.
3 MEMBER CORRADINI: Okay. So, to put it 4 crudely, AOOs are out per your understanding of 5 history.
6 MR. SCHMIDT: For 26 I think that it 7 doesn't address the upset condition.
8 MEMBER CORRADINI: Fine. Okay. I just 9 want to get clear what you thought.
10 MR. SCHMIDT: Yes, it does not address 11 the upset condition. It doesn't, it addresses the 12 day-to-day, normal operation of the plant.
13 MEMBER CORRADINI: Thank you.
14 MR. SCHMIDT: As previously discussed, 15 ARDC 26 kind of takes 26 and 27 and combines them 16 into one ARDC to deal with reactivity control under 17 AOO and postulated accidents.
18 In part, ARDC 26 was rewritten as the 19 term reliably controlling reactivity changes in both 20 GDC 26 and 27 was ambiguous. Revised ARDC 26 21 provides explicit performance criteria on the rate 22 and amount of negative reactivity insertion. ARDC 23 26 was significantly revised based on the ACRS and 24 public comments of the draft guide.
25 MEMBER BROWN: Can I ask a question?
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65 1 MR. SCHMIDT: Sure.
2 MEMBER BROWN: Where is any reference to 3 subcritical shutdown? Has that disappeared from ARDC 4 26?
5 MR. SCHMIDT: It actually does appear on 6 the next slide. So we'll go through this --
7 MEMBER BROWN: I mean, but it's not in 8 the new, it's not in the ARDC. If you say it's on 9 the next slide, I don't know what that means.
10 MR. SCHMIDT: Oh, yes, the next slide I 11 think is the -- I write down the specific ARDC, and 12 we go through individual words to show that.
13 MEMBER BROWN: Go ahead.
14 MR. SCHMIDT: Okay. So this was the 15 draft ARDC that went out, draft final, I'm sorry, 16 draft final.
17 So the first item, so it's broken up by 18 Items 1 and 2 are AOOs. Item 3 is postulated 19 accidents. And Item 4 kind of picks up the 20 reactivity requirements for getting what used to be 21 called cold shutdown in 26. But we've changed kind 22 of the meaning of cold.
23 So Item 1 is a means of inserting 24 negative reactivity at a sufficient rate and amount 25 to assure that the appropriate, what the appropriate NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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66 1 margin for malfunctions, that the design limits of 2 the fission product barriers are not exceeded and 3 safe shutdown is achieved and maintained during 4 normal operations, including AOOs.
5 MEMBER KIRCHNER: So are you going to 6 define safe shutdown?
7 MR. SCHMIDT: It=s safe shutdown 8 consistent with SECY-94-084.
9 CHAIRMAN BLEY: And they refer to that, 10 right? I think I remember B-11 MEMBER KIRCHNER: Yes, I saw that.
12 MR. SCHMIDT: Shutdown means 13 subcriticality.
14 MEMBER BROWN: Why do we have to have 15 some other document that makes that definition as 16 opposed to having that in the ARDC?
17 I just don=t understand why that=s 18 totally divorced from whatever the proposed design 19 criteria are. So it=s in the SECY paper. Is 20 somebody going to go back and B- that=s the SECY-94?
21 MR. SCHMIDT: Well, but, I mean, shutdown 22 means subcritical. So B-23 MEMBER BROWN: That=s not what we=ve been 24 listening to.
25 MR. SCHMIDT: Well, I guess --
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67 1 MEMBER BROWN: Shutdown and the comments 2 on B-3 (Simultaneous speaking.)
4 MEMBER KIRCHNER: So, Jeff or Dan, would 5 you have definitions? I don=t think there are 6 definitions in the current draft. Is there?
7 Now, the old GDCs that are in Appendix A 8 do have three definitions, because the original B-9 for example, they define single failure. Are you 10 going to use that same definition?
11 MR. SCHMIDT: Of single failure, for B-12 MEMBER KIRCHNER: Yes.
13 MR. SCHMIDT: I have assumed in this, 14 yes, that we=re using the single failure B-15 MEMBER KIRCHNER: Just a suggestion that 16 the preamble or whatever might benefit from 17 definitions of a few key words, and that=s one. We 18 were provided, or maybe, Dennis, you provided us the 19 original GDCs from B-20 CHAIRMAN BLEY: Well, almost original 21 proposed.
22 MEMBER KIRCHNER: And what they did when 23 they went to B-24 CHAIRMAN BLEY: I can=t say for sure.
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68 1 them now from Appendix A, they took that single 2 failure out as a criterion and made it a definition.
3 I believe it=s a definition in the current GDC.
4 MR. SCHMIDT: It is, yes.
5 MEMBER KIRCHNER: I think it would, like 6 Charlie, benefit to have a definition that is 7 unambiguous.
8 Safe shutdown, I can understand the 9 temperature issue is a little different than perhaps 10 a light water reactor. But certainly there should 11 be no misunderstanding. A shutdown is shut down.
12 And it means it=s subcritical. These systems then 13 are capable of keeping it subcritical.
14 MEMBER POWERS: My understanding, and I 15 think this is right, is that shutdown does mean 16 subcritical. The crucial difference here is safe 17 shutdown, which means there are additional 18 requirements, and that is that the fuel is cooled and 19 coolable for a long period of time.
20 There=s no ambiguity about shutdown as I 21 see it. The crucial term here is safe shutdown. Am 22 I wrong about something here?
23 CHAIRMAN BLEY: I agree with Dana. I 24 mean, safe shutdown means safe and shut down both.
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69 1 right. Fair enough.
2 MEMBER BROWN: I guess I=m a little 3 confused. When you talk about coolable, is that, 4 does that get you now into the realm where you can be 5 critical but coolable? Does that mean B-6 (Simultaneous speaking.)
7 MEMBER BROWN: You're shut down. And 8 you=re critical. And you=re coolable. And it=s 9 okay.
10 (Simultaneous speaking.)
11 CHAIRMAN BLEY: You can=t be shut down 12 and critical.
13 MEMBER BROWN: You=re both cooled and 14 coolable.
15 CHAIRMAN BLEY: There=s something 16 different going on in the other meeting we had than 17 this.
18 MEMBER BROWN: Well, there=s something 19 different going on in my brain I think.
20 (Laughter.)
21 MEMBER BROWN: I mean, subcritical to me 22 means subcritical. It doesn=t mean some other 23 ambiguous definition of what subcritical means. It 24 means --
25 CHAIRMAN BLEY: It means shut down.
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70 1 MEMBER BROWN: Okay. Effective is less 2 than one.
3 CHAIRMAN BLEY: Both cases, yes.
4 MEMBER BROWN: Well, but shutdown based 5 on some earlier discussions didn=t come across to me.
6 It seems we=ve got stuff B-7 (Simultaneous speaking.)
8 MEMBER BROWN: We=re wrapping 9 definitions around definitions to try to get to the 10 bottom line.
11 MEMBER POWERS: Well, there=s people 12 seeking a change in the world as we understand it and 13 shouldn=t be confused here. I mean, they=re saying 14 they want not just shutdown, they want safe shutdown.
15 And that has been the understanding for a very, very 16 long time.
17 MEMBER BROWN: Where is that defined 18 then? Where is the term safe shutdown defined? I=m 19 not aware B-20 MEMBER POWERS: Safe shutdown is defined 21 in the GDCs.
22 MEMBER BROWN: Where?
23 MEMBER POWERS: General design criteria.
24 MEMBER BROWN: I never saw it. When I=ve 25 scanned through and I B-NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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71 1 MEMBER POWERS: I think you can find it.
2 MEMBER KIRCHNER: I think it=s implied 3 B-4 (Simultaneous speaking.)
5 MEMBER BROWN: I=ve looked for 6 shutdowns, safe and subcritical. And I didn=t find 7 safe shutdown defined. And if I=m wrong, that=s 8 fine.
9 CHAIRMAN BLEY: I think there we just 10 fall back on nuclear engineering, which has defined 11 those terms.
12 MEMBER BROWN: That B-13 CHAIRMAN BLEY: They mean the same thing 14 here as they do anywhere else.
15 MR. SCHMIDT: That=s correct.
16 CHAIRMAN BLEY: Let=s not bring in the 17 discussion from the other meeting B-18 MEMBER BROWN: I=m just trying to focus 19 on these words, which are not in my own mind need to 20 have a definition. If we=re going to work on these 21 new design criteria, we ought to make sure that type 22 of a term is clearly understood as to what it means 23 relative to criticality, coolability of the fuel, et 24 cetera, somewhere so that people that are using these 25 now to adapt to their non-light water reactors NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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72 1 understand what that means.
2 CHAIRMAN BLEY: Point made.
3 MEMBER BROWN: Okay.
4 MR. SCHMIDT: Just to offer, we could 5 define safe shutdown consistent with that SECY paper 6 and put it in if that helps.
7 MEMBER KIRCHNER: I think that would be 8 valuable.
9 MEMBER SKILLMAN: Amen. I think that 10 would be a very good B-11 MEMBER BROWN: This is SECY-94-0 B-12 MEMBER SKILLMAN: 84.
13 MR. SCHMIDT: 084, yes.
14 MEMBER SKILLMAN: Yes, I think that would 15 really --
16 MEMBER BROWN: Let me go find that and 17 see --
18 MEMBER SKILLMAN: -- really address what 19 we are B-20 MR. SCHMIDT: Yes, I mean, the staff=s 21 intent was adequate cooling and subcritical.
22 MEMBER SKILLMAN: Yes, yes.
23 MR. SCHMIDT: In my mind, there=s no 24 ambiguity. But I have no problem B-25 MEMBER BROWN: Well, if that=s in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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73 1 SECY-94, it just, I guess my opinion would be B-2 MR. SCHMIDT: Move it to here.
3 MEMBER BROWN: -- that we ought to have 4 that, if we=re going to use those terminologies 5 somewhere in this thing, we ought to have definitions 6 of certain terminology that are used. And if the 7 SECY paper says that, it would be good to incorporate 8 that into these design criteria.
9 MEMBER SKILLMAN: Yes.
10 MR. SCHMIDT: I=m leaving it to these 11 two. That was the mass intent of my B-12 MEMBER SKILLMAN: Let me ask one 13 question. In the course of years, the word hold-down 14 has disappeared. But early on, those of us who were 15 deeply involved understood there was shutdown and 16 hold-down. And hold-down was the clamp that made 17 sure a shutdown stayed shut down.
18 MR. SCHMIDT: Right.
19 MEMBER SKILLMAN: Is there any way you 20 might weave hold-down into this? I believe it holds 21 up 94-84 in a way that really eliminates any ambiguity 22 as to what we=re talking about.
23 MR. SCHMIDT: I tried to address that 24 explicitly by the word maintained. And you=ll see 25 the difference, as we move from AOO to postulated NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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74 1 accident, that achieved and maintained softens for 2 Item 3. And we=ll get into that when we get to Item 3 number 3. I=m sure you=ll have a lot of questions.
4 MEMBER SKILLMAN: Okay. Thank you, 5 Jeff.
6 MR. SCHMIDT: Yes.
7 MEMBER KIRCHNER: Jeff, on number 2 B-8 MR. SCHMIDT: Yes, okay.
9 MEMBER KIRCHNER: -- I=m just reading the 10 words again afresh and thinking, could you put 11 independent and diverse up in the prologue, a minimum 12 of two independent and diverse reactivity control 13 systems, or means shall provide B-14 MR. SCHMIDT: Yes, that=s how the way the 15 current GDC is written. I=d have to think about that 16 some more in case there=s unintended consequences 17 associated with that.
18 MEMBER KIRCHNER: Yes.
19 MR. SCHMIDT: But it is consistent with 20 the current GDC 26.
21 MEMBER KIRCHNER: Yes, and because 2, as 22 I read it now afresh from the new guide, it says 23 independent and diverse from others. What others?
24 MR. SCHMIDT: The others in 1 and 3. So 25 that=s the B- it=s diverse from the other criteria in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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75 1 this list. That=s what it meant by others.
2 MEMBER KIRCHNER: But usually one of the 3 two in the preamble is going to do number 3 and 4 probably --
5 MR. SCHMIDT: Then you have --
6 MEMBER KIRCHNER: -- number 1.
7 MR. SCHMIDT: You can have one system do 8 multiple functions.
9 MEMBER KIRCHNER: Of course.
10 MR. SCHMIDT: Let=s say a boiler does a 11 1 and 3 with control rods alone. You're saying, I=m 12 saying you have to have another one, which is kind of 13 consistent with the way GDC 26 is right now, of 14 controlling reactivity.
15 So, if you take a look at B-16 MEMBER KIRCHNER: It=s almost, as I read 17 it, it almost like implied a third system.
18 MR. SCHMIDT: No, no, the intent B-19 MEMBER KIRCHNER: Okay.
20 MR. SCHMIDT: The intent is not to imply 21 a third system.
22 MEMBER KIRCHNER: Okay. All right.
23 MR. SCHMIDT: If you can do everything 24 with two B-25 MEMBER KIRCHNER: If that=s the way you NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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76 1 read it, fine.
2 MR. SCHMIDT: -- then do everything with 3 two. If you need four, you need four.
4 MEMBER KIRCHNER: All right.
5 MEMBER BROWN: Just to make sure I 6 understand, when we, number 3, when we say, once we 7 define safe shutdown so we know what that means, then 8 when we say with appropriate margin for malfunctions, 9 that=s intended to include something similar to one 10 rod stuck or whatever, and whatever the new non-light 11 water reactor looks like.
12 MR. SCHMIDT: That is correct.
13 MEMBER BROWN: And we don=t define 14 explicitly what those are. It=s just more general 15 terms. Okay.
16 MR. SCHMIDT: That is correct.
17 MEMBER BROWN: And don=t take my comments 18 as being I disagree with trend. I think the new GDC 19 26 amalgamating 26 and 27, the previous approach kind 20 of led to some ambiguity. And this, to me, had some 21 clearer stuff with the exception of some of the 22 nuances. So I understand what you=re saying now in 23 3. So thank you.
24 MEMBER SKILLMAN: Jeff, let me ask one 25 more.
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77 1 MR. SCHMIDT: Okay.
2 MEMBER SKILLMAN: The potential 3 misinterpretation of others on the underlined in the 4 first sentence of number 2, would you consider a means 5 which is independent and diverse from 1 above and 3 6 below instead of others?
7 MR. SCHMIDT: Right, right.
8 MEMBER SKILLMAN: Thank you.
9 MR. SCHMIDT: Okay. I think that=s a 10 good comment.
11 MEMBER SKILLMAN: Thank you.
12 MR. SCHMIDT: So Item 2 is actually in 13 direct response to the ACRS= comment, which was on 14 the previous slide. It=s where B- in an earlier 15 version, I remove the planned, normal power change 16 control. And it=s now reinserted back as Item number 17 2, just so everybody has a clear sense of B- that=s 18 a direct response to the ACRS comment.
19 CHAIRMAN BLEY: I got that reading --
20 MR. SCHMIDT: Okay. All right. Item 21 number 3 deals with the postulated accident. And 22 right now, as this is written, it=s talking about 23 safe shutdown following a postulated accident.
24 I=m going to defer 3 for a second, 25 because when I was putting these slides together, I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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78 1 realized I made kind of a mistake in 3 that I want to 2 propose a new Item number 3.
3 And the issue with Item number 3 that I 4 realized, and I never got any comments on, was I only 5 discuss what=s following the postulated accident, the 6 acceptance criteria, not the acceptance criteria 7 during.
8 And it was a miss on my part. And I 9 didn=t realize it until I put the slides together.
10 So I=m going to propose a new Item number 3.
11 CHAIRMAN BLEY: I look forward to seeing 12 that. But I=ll say, when I read it, to me following 13 the accident meant from the incident occurs from 14 thereafter B-15 MR. SCHMIDT: No.
16 CHAIRMAN BLEY: -- which is during.
17 MR. SCHMIDT: No, it does B-18 CHAIRMAN BLEY: So that isn=t what you 19 meant.
20 MR. SCHMIDT: It is not what I B-21 CHAIRMAN BLEY: That=s what I 22 interpreted.
23 MR. SCHMIDT: Right. It is not. So I=m 24 going to, after we go through 4, I=m going to go to 25 a back-up slide with a new version of number 3.
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79 1 CHAIRMAN BLEY: That sounds fine.
2 MR. SCHMIDT: So number 4 is really to 3 try to address GDC 26, the last item of cold shutdown 4 requirement. And here I got a lot of comments on the 5 cold portion of shutdown.
6 A means for holding the reactor shutdown 7 under conditions which allow for interventions such 8 as fuel loading, inspection, and repair shall be 9 provided.
10 MEMBER STETKAR: Jeff, I was just 11 thinking. Your proposed change to number 3, 12 currently operating pressurized water reactors would 13 not satisfy your proposed change to number 3.
14 MR. SCHMIDT: As written here.
15 MEMBER STETKAR: No, during. Large 16 steam line break, they go read critically --
17 MR. SCHMIDT: But the concept B-18 MEMBER STETKAR: -- during the accident.
19 MR. SCHMIDT: That=s right. See B-20 MEMBER STETKAR: They later go 21 subcritical, later.
22 MR. SCHMIDT: And that=s the exact thing 23 that we=re trying to parse out is following is the 24 long-term equilibrium state. What=s missing is the 25 short-term. So I agree with you.
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80 1 CHAIRMAN BLEY: So we ought to wait for 2 your slide, your back-up slide before we discuss.
3 MR. SCHMIDT: But I think that=s an 4 important point, is that, you know, this Item 3 as 5 written is the long-term kind of equilibrium state.
6 CHAIRMAN BLEY: Right, right.
7 MR. SCHMIDT: And I realized I never said 8 B- so, if you look at Item number 1, it basically 9 says, like it says basically protect the fission 10 product barriers during the whole event.
11 That is missing from Item 3 for 12 postulated accidents, so what=s your success criteria 13 for the during phase, not the short-term phase where 14 you=re actively mitigating I would say.
15 Is that clear what B-16 (Simultaneous speaking.)
17 CHAIRMAN BLEY: Can we go to your slide 18 before we continue the discussion?
19 MR. SCHMIDT: Yes.
20 CHAIRMAN BLEY: I think it will help.
21 MR. SCHMIDT: Okay. Let=s go to the 22 back-up.
23 CHAIRMAN BLEY: Well, I hope it will 24 help.
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81 1 proposed 3.
2 A means of inserting negative reactivity 3 at a sufficient rate and amount to assure with 4 appropriate margin for malfunctions that the 5 capability to cool the core is maintained and a means 6 of shutting down the reactor and maintaining at a 7 minimum safe shutdown condition following a 8 postulated accident.
9 So here=s your criteria for what I would 10 call the short-term. And it=s consistent with the 11 current GDC 27. It=s adequate cooling. And then in 12 the long-term, you should be shutdown.
13 CHAIRMAN BLEY: The thing that bothers 14 me here is just my reading. I mean, you had a problem 15 before with the original in that long-term is not 16 defined. We have a, I have a problem here in that 17 following --
18 MR. SCHMIDT: What's the definition of -
19 -
20 CHAIRMAN BLEY: -- at what point 21 following.
22 MR. SCHMIDT: Following, yes.
23 CHAIRMAN BLEY: You know, maybe after the 24 transient of the accident or something like that.
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82 1 in the rationale, because I agree.
2 CHAIRMAN BLEY: Yes, but will the 3 rationale be there in the long run? Is it going to 4 live with this document?
5 MR. SCHMIDT: Yes.
6 MEMBER BROWN: Yes, but will people look 7 at it when they=re doing a design? I mean, the notes 8 of how they got there, it=s difficult. In my own 9 mind, they=re going to look at these and say that=s 10 B-11 MR. SCHMIDT: I=m hoping they go to the 12 rationale.
13 CHAIRMAN BLEY: In the long-term would 14 work better for me here than following.
15 MEMBER BROWN: Exactly.
16 MR. SCHMIDT: I would be perfectly fine 17 with that. I think you then have the question of 18 what is the long-term. But I=m not sure B-19 MEMBER KIRCHNER: Can you, Jeff, without 20 having too many words, couldn=t it be during and 21 following the postulated?
22 MEMBER CORRADINI: No, because current 23 light water reactors don=t sense that.
24 MEMBER KIRCHNER: But we=re not writing 25 this for current. We=re writing it for advanced NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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83 1 reactors.
2 MR. SCHMIDT: But it's -- that=s true.
3 But it=s within, the context is what are we currently 4 kind of licensed to a situation for PWRs during main 5 steam line break that has short-term reciprocality.
6 The idea was not to impose additional requirements 7 necessarily on non-light water reactors.
8 So I understand what you=re saying. But 9 I think that=s B- I tried to keep the current 10 construct but add clarity that in the long-term you 11 should have like shutdown rods or some means of going 12 subcritical at the end of the day.
13 MEMBER REMPE: But in the long-term 14 really kind of B-15 MEMBER KIRCHNER: But do you now move the 16 position of achieving safe shutdown from your first 17 draft, right?
18 MR. SCHMIDT: Yes, you=re right. So the 19 original one had shutdown was the specific 20 performance requirement. And I got numerous comments 21 on that was effectively requiring additional 22 regulations that=s not supported in the current GDC.
23 MEMBER BROWN: Why wouldn=t some words 24 like subsequent to the initial transient and 25 mitigating actions following a postulated accident?
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84 1 I mean, that=s what you=re really talking 2 about. The accident occurs. The transient get 3 there. The mitigating actions are taken. And then 4 you have to deal with the following, the stuff that 5 follows on after that.
6 MR. SCHMIDT: I think, I mean, in my 7 opinion B-8 MEMBER BROWN: It=s a struggle B-9 MR. SCHMIDT: -- this is what this says, 10 and it=s kind of consistent with the current GDC 27 11 language. So I=m not trying to reinvent the language 12 as much.
13 What I really was trying to answer in 14 this -- it=s very consistent with the current 15 language of GDC 27 other than I=m having the safe 16 shutdown following the postulated accident B-17 MEMBER KIRCHNER: But these again are for 18 advanced reactors and their guidance. And they don=t 19 apply to LWRs.
20 MR. SCHMIDT: Right.
21 MEMBER KIRCHNER: And for an advanced 22 reactor, we expect better performance, right? Isn=t 23 that -- there's some commission statement along those 24 lines.
25 MR. SCHMIDT: I=m not sure that B-NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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85 1 MEMBER CORRADINI: I guess I=ve been 2 quiet. So now I won=t be.
3 It strikes me that, as long as the core 4 remains cool and there is no challenge to the fuel, 5 that this is consistent with what we=ve got now. I=m 6 not sure I need to be more safe than what we have now 7 for current reactors. That=s what I thought Jeff was 8 saying.
9 MR. SCHMIDT: That is what I=m saying by 10 the capability to cool the core is maintained, which 11 is language consistent with GDC 27 today. But that=s 12 a philosophical B-13 MEMBER CORRADINI: I understand.
14 MR. SCHMIDT: -- point of whether you 15 want it to be shutdown is a safer configuration than 16 what is currently in our GDCs and what has effectively 17 been portered over to ARDC 26. What is spelled out 18 is the shutdown requirement in the long-term.
19 CHAIRMAN BLEY: Just for Walt=s point, 20 the thing you were looking for from the commission is 21 on page 6 of the Reg Guide.
22 MEMBER KIRCHNER: It is?
23 CHAIRMAN BLEY: Yes, the core is in 24 there.
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86 1 forth, I thought I heard you say, oh, you ought to 2 change that word to in the long-term. And I thought 3 someone up there took a note saying, oh, yes, we could 4 do that.
5 But I think if you bring in that new 6 phrase without explaining it, you=re going to have a 7 lot of questions. And so I=d like to add the caveat 8 to making a word change.
9 CHAIRMAN BLEY: I think what they=ve 10 done, as long as this stays in the long-term, having 11 the rationale there works.
12 MR. SCHMIDT: The rationale tried to 13 explain what following meant. And I don=t want to 14 put everything in the ARDC.
15 CHAIRMAN BLEY: I think you did a great 16 job in the rationales across the board. They=ve 17 really helped me in reading through this.
18 MR. SCHMIDT: So I would propose, since 19 I think the draft guide missed kind of the boat, I 20 would propose that this be the third item. So our 21 proposal is that this would go into the final Reg 22 Guide.
23 MEMBER BROWN: I guess along with some 24 definition of safe shutdown.
25 MR. SCHMIDT: I am not opposed to that.
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87 1 But I=m going to leave it to these guys because 2 they=re the controllers of the Reg Guide.
3 (Off mic comments.)
4 MR. SCHMIDT: Was there any question on 5 4, though, on the cold shutdown before we leave that?
6 MEMBER SKILLMAN: Jeff, one of the, a 7 question about your choice of the word interventions.
8 That=s a new term. And I don=t think there=s 9 anything fundamentally inappropriate with it.
10 But it would seem to me that the jargon 11 that we use in the industry might be, either you=re 12 adding a word to our lexicon, or you would use a word 13 which allowed for normal activities such as fuel 14 loading and refueling, inspection and repair, unless 15 you had a reason for interventions to make it 16 substantially different from jargon that we=ve used 17 historically. Nothing wrong with it. It just kind 18 of jumps out as a brand new word.
19 MR. SCHMIDT: You know, the thought 20 process was there=s an old Reg Guide, which I=m not 21 remembering the number, that said, you know, one of 22 the functions of getting to cold shutdown was to be 23 able to, following a transient, following either an 24 AOO or postulated accident, was to get down to cold 25 to be able to inspect and repair. So I used the word NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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88 1 intervention kind of in that vein of the intent of 2 that original Reg Guide.
3 CHAIRMAN BLEY: You have a reference to 4 that somewhere in this document. I remember reading 5 it.
6 MR. SCHMIDT: Yes, I do, I do. But 7 that=s B- I=m not necessarily wed to interventions.
8 But I B-9 CHAIRMAN BLEY: Can I make a caution for 10 you guys? We aren=t editing this for you on the fly.
11 We=ve suggested, at least for me, things that come 12 off the tops of our heads. Be careful as you consider 13 those things that are comments in the throes of a 14 meeting here.
15 MR. SCHMIDT: Right. But I guess my real 16 statement was I don=t B- interventions was just to B-17 MEMBER SKILLMAN: Or maybe it=s a good 18 thing, because you=re the author. And I wasn=t 19 trying to change your mind. It just seems we=ve got 20 a lexicon that we=ve used for years. This was 21 different. Maybe it=s appropriate to embed a new 22 term.
23 MR. SCHMIDT: Okay.
24 MEMBER SKILLMAN: Up to you.
25 MR. SCHMIDT: Okay. Thank you.
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89 1 (Off mic comments.)
2 MR. SCHMIDT: Yes, I think we've gone --
3 so I guess this is a lot we=ve talked about.
4 Basically, Item 1 is we talked about the 5 specific words that were added. The original guide 6 talked more, the original ARDC 26 in an earlier draft 7 talked more about shutdown. And there was a lot of 8 confusion. Is it only shutdown related? And the 9 answer is no. It=s consistent with the current GDC 10 26 is you got to get a sufficient rate and amount to 11 protect the SAFDLs or the primary coolant boundary.
12 And those are the fission product 13 barriers we=re talking about is fuel and coolant 14 barrier. And again safe shutdown was added. I think 15 those are specific performance criteria.
16 CHAIRMAN BLEY: Well, I was looking over 17 John=s shoulder here. He=s been rummaging through 18 the regulations. And if you do define safe shutdown, 19 you=ve got the one document you=ve cited, but also 20 Part 50 has a definition, too.
21 MR. SCHMIDT: Yes, 50.2, you mean --
22 CHAIRMAN BLEY: Yes, be sure to look to 23 at that.
24 MR. SCHMIDT: -- the SSEs --
25 CHAIRMAN BLEY: Yes.
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90 1 MR. SCHMIDT: -- related? Yes, right, 2 right.
3 And then Item 2, we've talked about a 4 means, which is independent and diverse from the 5 other ones in this list, shall be capable of 6 controlling the rate of reactivity changes from 7 planned, normal power changes.
8 Again, this was added for ACRS comments.
9 And the purpose is to provide additional protection 10 of fission product barriers and limit and challenges 11 to the protective action. So we're trying to limit 12 any protective actions that may be required by just 13 doing a good job controlling reactivity changes.
14 Again, this is kind of what we have 15 talked about. The word following was included to 16 establish that safe shutdown should be achieved in 17 the long-term equilibrium state, allows re-18 criticality in the short-term consistent with some 19 licensed PWR postulated accident if sufficient heat 20 removal capability exists to survive that.
21 MEMBER SKILLMAN: And, Jeff, are these 22 the new words or the old? You're going to adapt 23 these slightly for the new text?
24 MR. SCHMIDT: So the words for 3 changed.
25 The intent of the bullets below does not change.
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91 1 MEMBER SKILLMAN: Okay.
2 MR. SCHMIDT: It was never our intent to 3 change those.
4 MEMBER SKILLMAN: Thank you.
5 MR. SCHMIDT: I just realized I had 6 missed.
7 MEMBER SKILLMAN: When you wrote the 8 bullets.
9 MR. SCHMIDT: When I wrote the bullets, 10 I realized I didn't really address the during 11 criteria.
12 MEMBER POWERS: When you use the word 13 equilibrium state, what you, I think what you mean 14 here is the quasi-equilibrium or long-term state --
15 MR. SCHMIDT: Right, right. That's 16 right. So, you know, it's somewhat in the construct 17 of expecting that future designs will be generally 18 passive. And that's why I use the word equilibrium, 19 right.
20 So, say if it cools down and it has a 21 potential of becoming re-critical, there should be 22 some system that might be active to stop that, right?
23 So the equilibrium state was to try to denote maybe 24 the passive nature of future plants.
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92 1 you have is all the source trend people, equilibrium 2 means something very different to us. And your 3 equilibrium is not the same as our equilibrium. And 4 we're still releasing fission products out of this 5 thing.
6 MR. SCHMIDT: Right.
7 CHAIRMAN BLEY: Perhaps steady state, 8 but we don't --
9 MEMBER POWERS: Well, the steady state 10 or quasi-equilibrium cooled state is something to be 11 considered. I don't question. I put this up to 12 understand. And maybe in the, as you elaborated 13 these paragraphs before, it becomes very clear that 14 you're talking about a thermal equilibrium --
15 MR. SCHMIDT: Yes.
16 MEMBER POWERS: -- here. And you don't 17 need to change things here, because there's a lot of 18 words here that come from the skill of the art. And 19 fair enough. That's perfectly acceptable, otherwise 20 the criteria becomes so long and the definitions so 21 abstruse that nobody can read it.
22 MR. SCHMIDT: Right.
23 MEMBER POWERS: But just remember that 24 those of us that have to worry about 10 CFR Part 100 25 here are going to be still worried for 30 days.
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93 1 MR. SCHMIDT: -- noted.
2 MEMBER SUNSERI: Well, I would suggest 3 that maybe you don't even need to qualify the term 4 long-term. Just leave it at long-term, because the 5 rest of the ADRC defines the state.
6 (Simultaneous speaking.)
7 MR. SCHMIDT: Yes.
8 MEMBER POWERS: Well, there are a lot of 9 people that worry about 10 CFR Part 100.
10 CHAIRMAN BLEY: Yes, that's true.
11 MEMBER POWERS: And they have to worry 12 for 30 days.
13 MR. SCHMIDT: You know, the long-term 14 equilibrium states in the rationale and there is --
15 you know, we try to find the right wording to address 16 this condition. And I think this is the best we 17 could come up with.
18 MEMBER POWERS: Fair enough. I mean, 19 don't --
20 MR. SCHMIDT: Okay.
21 MEMBER POWERS: Just understand that, 22 for instance, now I am still agonizing over how to 23 describe fission product release from the Fukushima 24 fuel.
25 MR. SCHMIDT: Right, right, right.
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94 1 MEMBER POWERS: Okay.
2 MR. SCHMIDT: What's the equilibrium 3 state?
4 MEMBER POWERS: Because it is occurring 5 and it is causing headaches for those people that are 6 trying to recover the reactors.
7 MR. SCHMIDT: I mean, in some sense, you 8 know, these are reactivity --
9 MEMBER POWERS: Yes, it is.
10 MR. SCHMIDT: -- GDCs. And you have to 11 put it in this first perspective. What's your 12 equilibrium reactivity state? And obviously, 13 multiple things affect reactivity.
14 MEMBER POWERS: I understand and hope it 15 can contain just one --
16 MR. SCHMIDT: Go ahead, Jan.
17 CHAIRMAN BLEY: If we're ready to move 18 on, we're going to take a short break. Do you have 19 more?
20 MR. SCHMIDT: No, we're -- other than, 21 if you don't have any questions on 4, I am done.
22 CHAIRMAN BLEY: Going, going. We will 23 recess for 15 minutes until 10:55. We will also go 24 until 12:30. Some of our members will have to leave 25 for another session --
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95 1 MEMBER POWERS: I will quickly point out 2 that 212 boiling point of water is true only at sea 3 level. Reactors built for IM would have to have much 4 colder --
5 (Laughter.)
6 (Whereupon, the above-entitled matter 7 went off the record at 10:40 a.m. and resumed at 10:56 8 a.m.)
9 CHAIRMAN BLEY: Okay, we are back in 10 session. Jan, I'll turn it back over to you.
11 MS. MAZZA: Thank you. So next we're 12 going to have a presentation on electric power 13 systems, which is ARDC 17 and Bob Fitzpatrick is going 14 to do a presentation on that. Bob?
15 MR. FITZPATRICK: Good morning; I'm Bob 16 Fitzpatrick with the Electrical Engineering Branch in 17 NRR. Next slide.
18 The ACRS comment that came out in the 19 March of '17 letter was the staff should improve the 20 clarity of ARDC 17 with respect to the term "vital 21 functions." Even if electric power is not needed for 22 operational equipment, reliable power is still needed 23 for monitoring plant status, habitability, lighting 24 and communications. And this was not the only good 25 comment to come out of the ACRS, it didn't make the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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96 1 letter, but also you said at the time in the meetings 2 that we should expound upon what we meant by just 3 systems as we get into this, and so we did that as 4 well. And also note that basically your comments 5 were pretty close to industry, so everyone was 6 thinking we need more specificity and clarification 7 but not necessarily more regulation, so.
8 If we can have the next slide.
9 What I've done here is the next slides 10 are exactly what's in our draft, final version of the 11 reg guide, and I've highlighted some of the words to 12 point out what we've changed or what we've emphasized 13 along the way. So this is Paragraph 1 of our ARDC 14 17, which by the way is exactly the same electrically 15 as SFR 17 and MHTGR 17; we make no distinction 16 electrically between any of the designs. So when we 17 said "electric power systems," that was one of your 18 first comments that we should beef that up a bit.
19 And the one required actually came from industry, the 20 public. We may or may not need electric power 21 systems because these are advanced designs that are 22 considered probably to be passive to at least some 23 extent. So we put that in there to not just appease 24 but to agree with and, just whatever. Anyway, we put 25 it in there so it makes that distinction, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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97 1 functioning of systems, structures and components and 2 the safety function for each power system. A little 3 more emphasis on more than one shall be to provide 4 and then the two items that are provided there.
5 So we can move onto No. 2, Paragraph 2.
6 Now it goes the electric power systems 7 shall be comprised of an on-site power system and an 8 additional power system. The on-site power system 9 shall have sufficient independence, redundancy and 10 testability to perform its safety functions assuming 11 a single failure. And an additional power system 12 shall have sufficient independence and testability to 13 perform its safety function. And we expound on this 14 in the rationale.
15 And then we added a third paragraph which 16 was not there before, and this was back to the 17 importance of safety. If electric power is not 18 needed for anticipated operational occurrences, 19 accidents, the design shall demonstrate that powerful 20 and important safety functions is provided. And we 21 also expound on that in the rationale.
22 CHAIRMAN BLEY: This is kind of minor, 23 but I noticed the words on your previous slide aren't 24 identical to the words in the draft I'm reading. For 25 example, "shall be comprised of, shall include."
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98 1 MR. FITZPATRICK: Oh.
2 CHAIRMAN BLEY: Which is, that's not a 3 big deal, but which is right? Did you make changes 4 since you sent us the draft?
5 MR. FITZPATRICK: I may have grabbed the 6 wrong version to put in here.
7 CHAIRMAN BLEY: Except for that, it looks 8 pretty -- go ahead, but check on what you --
9 MR. FITZPATRICK: Yes, so we'll 10 certainly check on it. I just don't know the answer 11 to that. But we certainly didn't try to change the 12 meaning in the process.
13 So going onto the rationale to support 14 these three paragraphs is the next slide.
15 All right, so I'll go through it, but we 16 really added for new things is at the bottom. The 17 electric power systems are required to provide 18 reliable power for SSC's during anticipated 19 operational occurrences or postulated accident 20 conditions when those SSC safety functions require 21 electric power. So again, a distinction that may 22 not, but if they do, this is what it is. The safety 23 functions are established by the safety analyses --
24 yes, that's it, which includes mitigating the design 25 base as accidents.
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99 1 Where electric power is needed for 2 anticipated operational occurrences or postulated 3 accidents, the electric power systems shall be 4 sufficient in capacity and capability to ensure that 5 safety functions as well as important safety 6 functions are maintained. The electric power systems 7 provide redundancy and defense-in-depth since there 8 would be a minimum of two power systems.
9 MEMBER STETKAR: Bob, why do you need to 10 distinguish between safety functions and important to 11 safety functions?
12 MR. FITZPATRICK: Well, in this case the 13 safety functions of a perspective we put in here is 14 that that would be something where you needed like 15 motor power; a motor, a pump, something along the 16 way. An importance to safety is those support system 17 type functions that we talked about previously at 18 previous meetings.
19 MEMBER STETKAR: I guess I don't really 20 follow the distinction; either something is important 21 to safety or it's not important to safety. And if 22 it's important to safety, it ought to have power; and 23 if it's not important to safety, you can talk about 24 it. I don't distinguish between a mode of power or 25 a power for an instrument that might be useful to an NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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100 1 operator. If it's important to safety, it's 2 important to safety. I just don't get it.
3 MEMBER SKILLMAN: Yes, I'd like to agree 4 with John; it seems like you could have a SSC that 5 truly is a device that has to change physical status 6 because it's powered and it is a safety component, 7 but the exit lighting under fire conditions is also 8 the safety function. And unless these words are 9 clear to ensure that instrumentation, lighting and 10 some of what we might consider minor functions are 11 highly important. They can get left out, so I think 12 there is basis for ensuring that this applies not 13 only to powers SSC's but also to subordinate safety 14 functions that are there for the unit.
15 MR. FITZPATRICK: Right. Well, we've 16 added a paragraph and a rationale for that that's I 17 think like two paragraphs down from this.
18 If we can have the next slide.
19 This slide, compared to GDC 17 more 20 emphasis is placed here on requirement or reliability 21 of the overall power supply scheme rather than fully 22 prescribing how such reliability can be obtained.
23 For example, reference to the off-site electric power 24 systems was deleted to provide for those reactor 25 designs that do not depend on off-site power or the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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101 1 functioning SSC's important to safety or do not 2 connect to a power grid, so we didn't make any 3 changes. This is getting back down to into what we, 4 on the next slide, No. 3, what we've been talking 5 about here.
6 The on-site power system is envisioned as 7 a fully class-winning power system. Any additional 8 power system is left to the discretion of the designer 9 as long as it leads to the performance criteria in 10 Paragraph 1 and the design criteria of Paragraph 2.
11 For example, an additional independent power source 12 could be from the electrical grid, a diesel 13 generator, a combustion gas turbine or some other 14 alternative, again, at the discretion of the 15 designer. So we tried to put that specificity in 16 here as what it might be, but leaving it to the 17 designer to come up exactly what it is going to be.
18 The next paragraph.
19 And the important to safety functions 20 include post-accident monitoring, control room 21 habitability, emergency lighting, radiation 22 monitoring, communications, and/or any others that 23 may be deemed appropriate for the given design. The 24 electric power system for important to safety 25 functions could be non-class 1E and would not be NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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102 1 required to have redundant power sources.
2 MEMBER STETKAR: Bob, have you looked at 3 the rest of the NRC and what they mean by "important 4 to safety?" This strikes me as being not consistent 5 with the NRC's use of the term "important to safety" 6 throughout its regulatory guidance, and in the 7 context in particular of risk-informed regulation of 8 how an applicant can use perhaps their own criteria 9 to determine what is or is not important to safety, 10 and that's a term. You've redefined that term 11 specifically in this rationale differently from its 12 use throughout the rest of the agency, so I'm curious 13 why you did that?
14 MR. FITZPATRICK: We just try to make a 15 distinction between, like I said, equipment that 16 needs motive power.
17 MEMBER STETKAR: Equipment that needs 18 motive power is equipment that needs motive power.
19 That doesn't have anything to do with being important 20 to safety or not important to safety.
21 MR. FITZPATRICK: Well --
22 MEMBER STETKAR: Important to safety is 23 -- I'm not going to say it again because we're pressed 24 for time here -- take a look at it, please, from my 25 perspective, because --
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103 1 MR. FITZPATRICK: We will take a look at 2 that.
3 MEMBER STETKAR: -- it is a term that is 4 used quite extensively throughout the agency. And 5 indeed, we've had with the ACRS some discussions 6 about what particular criteria might a particular 7 applicant use to determine which particular equipment 8 or functions is over the line, if you will, as being 9 important to safety or under the line as being deemed 10 not important to safety.
11 MS. RAY: This is Sheila Ray from the 12 staff in NRR, Electrical Engineering New Reactor and 13 License Renewal Branch. We tried to keep it a bit 14 open when we included "important to safety functions" 15 in the rationale. We said these are things that may 16 include, but we did not have the intention of defining 17 it. We said these are some examples but the design 18 may have to consider other items that are important 19 to safety.
20 CHAIRMAN BLEY: I think -- you were 21 trying to respond, I think, to comments from various 22 people in the past that said we need to have some way 23 to monitor the plant after an accident, and that's 24 what all of these are looking at. Elsewhere in the 25 regulations, "important to safety," at least in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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104 1 places I'm aware of it, means the risk assessment 2 showed that in fact they were contributors to risk.
3 And I think John's right, this was confusing what 4 everybody else means by "important to safety." And 5 some other words here you're really going after 6 monitoring, so something that will get you out of the 7 woods. But that's what you're after and it'll avoid 8 some confusion.
9 MEMBER STETKAR: This is a case, if you 10 just -- again, it's a subcommittee meeting, you're 11 hearing individual feedback, but if you can edit the 12 rationale to just make sure that applicants, 13 designers and reviewers recognize that they need to 14 be cognizant of the ability of the operators to 15 monitor plant performance. Without getting into 16 this, is it motive, is it -- despite the fact that 17 you might not need AC or DC power in terms of a motive 18 capability, but just bring out this notion of 19 retention of capability for operators to monitor 20 plant status.
21 MR. GREEN: Yes, Brian Green, NRC staff.
22 We've took this comment back after I believe it was 23 a November meeting, a similar concern was brought up 24 about monitoring and there were some changes made in 25 ARDC 19 to help alleviate some of that. I don't NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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105 1 think it's planned in the discussion today, but a 2 quick recap is that much of the words from GDC 19 3 about the operators having a control room where they 4 can safety control the plant was maintained but the 5 rationale was expanded to describe that the operators 6 must be able to monitor in order to safely control 7 the plant. So there was some additional rationale 8 added to help clarify that concern.
9 CHAIRMAN BLEY: Okay, our comments here 10 weren't about the concept. We agree with the 11 concept; I think most of us agree with the concept, 12 at least I do. But particular language.
13 MEMBER STETKAR: Jan?
14 CHAIRMAN BLEY: We can't hear you. You 15 couldn't hear me either.
16 MS. MAZZA: I'm sorry. That concludes 17 electric power systems, so now we're going to move 18 onto containment and Imtiaz Madni is going to present 19 on that.
20 MR. MADNI: Good morning; this is Imtiaz 21 Madni from NRO and I'll be talking about the 22 containment design criteria. So next slide.
23 This slide shows ACRS comments on the 24 containment design criteria from the letter dated 25 March 21st, 2017. ARDC 16, the functional NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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106 1 containment performance requirement is vague and 2 needs to be defined. For example, the phrases 3 "essentially leak-tight" or "low leakage" are not 4 adequately defined. An examination for the 5 possibility of reactor pressure boundary failure to 6 induce the containment failure should be included 7 explicitly. So here we have three comments in there; 8 the first one is "essentially leak-tight" and that 9 refers to the language in the ARDC 16. The next one 10 is "low leakage" and that refers to the language in 11 SFR-DC16. And then for the third one, except for 12 MHTGR's, all other currently proposed advanced 13 reactor designs are low pressure, so it's interpreted 14 that the final sentence in the comment is in reference 15 to MHTGR-DC16; however, we do address primary coolant 16 boundary failure for SFR-DC16 as well in respect to 17 this comment.
18 MEMBER KIRCHNER: You weren't here 19 earlier, Imtiaz, when I made some comments about 20 generic application of your requirements. You once 21 again, I think, fall into a trap of assuming 22 performance of one of these advanced designs and the 23 whole family of accident sequences, but I can imagine 24 not only HTGR operates at high pressure, so you have 25 the possibility of a pipe break there. But with a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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107 1 sodium-cooled reactor, should you have a sodium water 2 reaction you're going to generate lots of energy, 3 lots of pressure. Now, conventional containments for 4 LWR's have, what should I describe it, resilience 5 against some of the consequences that they will see 6 in their accident scenarios. So why jump to an 7 exception for the HTGR?
8 MR. MADNI: Well, the helium pressure 9 boundary is very high pressure, not to the extent of 10 LWR's, but it's high pressure. But if you look at 11 the sodium-cooled reactor, for example, it's 12 operating. And so it's only when something happens, 13 let's say there's a boundary failure, so it's not a 14 pressure boundary failure as the terminology, that 15 the terminology will be it's a coolant boundary 16 failure because pressure boundary implies that uses 17 high pressure. But nonetheless, as I mentioned, that 18 we do address the failure of this sodium-cooled 19 reactor pressure boundary as well.
20 MEMBER KIRCHNER: I understand it's low 21 pressure but the consequences of a failure in such a 22 design, and should you encounter a steam generator 23 rupture or something like that and you mix the coolant 24 with the water, can result in a significant pressure 25 pulse.
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108 1 MR. MADNI: I will say really --
2 MEMBER KIRCHNER: Just like a hydrogen 3 burn would give you a pressure pulse and LWR.
4 MR. MADNI: I was referring to the 5 specific comment that was made by ACRS. An 6 examination for the possibility of reactor pressure 7 boundary failure, reactor pressure boundary failure, 8 not intermediate, reactor pressure boundary. So the 9 reactor boundary is actually atmospheric pressure, 10 not high pressure. If you want to talk about 11 intermediate system, that could be something else.
12 And we will cover that also. But I'm just responding 13 to the ACRS comment.
14 MEMBER KIRCHNER: Okay.
15 MR. SOFU: Tanju Sofu from Argonne 16 National Lab. The steam generators are usually, 17 almost always outside the containment, so steam 18 generators, tube rupture would not result in any --
19 MEMBER KIRCHNER: We don't know that yet.
20 Again, that's an a priori adaptation of the GDC's to 21 the anticipated design and its performance.
22 PARTICIPANT: And it's unstated.
23 MEMBER KIRCHNER: And it's unstated, 24 yes. Now if you stated that the water systems had 25 to be outside containment, it would be a different NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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109 1 matter.
2 MR. MADNI: So we go to the next slide.
3 This slide addresses the RDC content and the NRC 4 rationale for adaptations to the GDC. And for the 5 ARDC 16 content NRC plans to use the current GDC 16.
6 You may recall that this is the first proposal which 7 was for the functional containment for the RDC. By 8 coming to the NRC rationale the first bullet says 9 "For non-LWR technologies other than SFR's and 10 HTGR's, designers may use the current GDC to develop 11 applicable PDC's or potential design criteria."
12 However, non-LWR designs could share common features 13 with SFR's and HTGR's; hence designers may propose 14 using SFR-DC or HTGR-DC as appropriate. And the use 15 of MHTGR-DC16 will be subject to a policy decision by 16 the commission, and this policy decision will be 17 addressed in the Functional Containment Performance 18 Criteria SECY paper that Jan mentioned earlier, and 19 the reg guide may be modified in the future to 20 incorporate the commission's position on this.
21 MEMBER KIRCHNER: May I interject here?
22 Jan went through this; what's the time frame for that 23 policy decision by the commissioners?
24 MS. MAZZA: So the draft paper has been 25 written and gotten feedback from the public in some NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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110 1 of our stakeholder meetings. Bill Reckley will be 2 here on the 22nd of February to talk to you all about 3 it. And then the Commission had asked how quickly 4 we needed a decision on that yesterday, so I'm not 5 sure exactly what the time frame as far as what their 6 decision will be.
7 MR. SEGALA: Yes, and I think we're 8 shooting for this spring to issue the SECY paper.
9 MEMBER KIRCHNER: Okay, so we have --
10 it's still about GDC, so I'll go to the paper that we 11 have on functional containment performance, and it 12 does summarize your three different version of GDC 16 13 and starts with the advanced reactor containment 14 criteria being the same. The SFR being somewhat 15 different, but then the SFR has a second paragraph, 16 which I actually like if you're going to go to 17 functional performance; the containment leakage shall 18 be restricted to be less than that needed to meet the 19 acceptable on-site and off-site dose consequent 20 limits as specified in 10CFR50.34 for postulated 21 accidents. That gets at the weakness in what is an 22 essentially leak-tight barrier; well, it's got to be 23 tight enough to prevent that occurring. So it seemed 24 to me -- and then you would do mechanistic source 25 terms, you would look at your barriers whether it's NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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111 1 HGTR or a sodium reactor or some other undefined 2 advanced reactor. But I'm struggling with your 3 having three different takes on what is containment.
4 MR. MADNI: Which slide are you referring 5 to?
6 MEMBER KIRCHNER: I'm not referring to 7 your slides, actually; I'm just reading the GDC's, 8 they were summarized in your functional containment 9 document.
10 MR. MADNI: Oh, okay.
11 MS. MAZZA: So as far as the advanced 12 reactor design criteria, we kept that the same as the 13 general design criteria because the issue of 14 functional containment seemed to be a modular high-15 temperature gas reactor issue in the policy papers, 16 like 93-092 and 030 and 047.
17 MEMBER KIRCHNER: I don't think so.
18 MS. MAZZA: But --
19 MEMBER KIRCHNER: You're heading down 20 the path of doing performance-based containment.
21 MS. MAZZA: Correct. But we didn't want 22 to get --
23 MEMBER KIRCHNER: Risk-informed, et 24 cetera. So if you're going in that direction, why 25 don't you try and create a design criteria for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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112 1 advanced reactors that envelopes and embraces where 2 you're going?
3 MS. MAZZA: Correct.
4 MEMBER KIRCHNER: Otherwise.
5 MS. MAZZA: Yes, and we agree with that.
6 And that's something that we may change in the reg 7 guide once we get this policy decision because staff, 8 we feel that we have --
9 MEMBER KIRCHNER: But why do you want the 10 policy decision for just HTGR's?
11 MS. MAZZA: We want it for everything; 12 it's going to be a technology inclusive policy 13 decision. We didn't want to get ahead of the policy 14 decision by putting that in here.
15 MEMBER KIRCHNER: You should then 16 construct what would be a satisfactory for you, the 17 regulators, not for the industry, for you, what is 18 your idea of the approach that you're going to use 19 for functional containment performance.
20 MS. MAZZA: That's what the SECY paper 21 will do unless we get an answer from --
22 MEMBER CORRADINI: I'm just -- you guys 23 seem to me either in violent agreement or missing 24 each other. So what I thought Walt is getting at is 25 that if you go through all this effort to develop NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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113 1 something that is, I'll call a new direction, it ought 2 to be applicable to all. And your answer back is 3 that it is. But as you state the criteria, the ARDC 4 is the old GDC 16 and --
5 MEMBER KIRCHNER: The SFR is something 6 else.
7 MEMBER CORRADINI: And the SFR is 8 something else and the reactor --
9 MEMBER KIRCHNER: HGTR is something 10 else. And you're using different terminology, so now 11 I'm confused where you're going with this. Again, 12 you want to be -- it's the first order, it's not 13 always possible -- technology neutral. I think 14 you've got an envelope a way of going, I'm just trying 15 to help you along.
16 MEMBER CORRADINI: As a personal 17 opinion.
18 MEMBER KIRCHNER: But I don't think 19 you're helping -- as a personal opinion, as one 20 member, but I don't think it behooves the agency to 21 have three different definitions for containment, 22 principle design criteria.
23 MEMBER BROWN: A side observation from 24 looking at it; if you look at the ARDC which is the 25 same as the existing one and you look at the MHTGR NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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114 1 which is kind of the same, you've got the second 2 paragraph in here for the SF, the sodium fuel, which 3 really provides kind of a definition of what leakage 4 means, almost like I'd put that paragraph in each one 5 of the containment criteria of 16. The other words 6 just say you should control it in all three of them 7 to meet "important to safety" or "not violated" or 8 "not exceeded," where as that's kind of mushy, where 9 as that second paragraph really provides the boundary 10 conditions on what leakage is allowed. It's to meet 11 radiation dose limits for both on-site and off-site.
12 MEMBER KIRCHNER: Right.
13 MEMBER BROWN: So I mean, if we're going 14 to go change these or make it better, more 15 informative, then you ought to put that in all of 16 them.
17 MR. MADNI: But when you have these 18 design criteria for MHTGR, we know it's functional 19 containment. But we also know that there's still a 20 policy position that's going to hold up any 21 regulatory effort in that direction. And for ARDC 22 which is technology inclusive you do not know what 23 the new design is going to be, so if you --
24 MEMBER KIRCHNER: You don't know what the 25 HTGR design is going to be?
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115 1 MEMBER BROWN: But letting radiation 2 dose exceed, why is that -- those words are as about 3 technology neutral as you can get. It just says we 4 shouldn't expose people either on-site or off-site.
5 MR. MADNI: But if the ARDC happens to 6 be like SFR, then your definition will be according 7 to the SFR-DC16. And if it were like MHTGR it would 8 be that. But what if it comes up with something else 9 where functional --
10 MEMBER BROWN: That's my point; don't 11 these words mean the same anyway? Whether it's 12 something else, you just still don't want to expose 13 people either on-site or off-site? That is such --
14 MEMBER KIRCHNER: Basic.
15 MEMBER BROWN: -- basic definition, a 16 principle of all designs that we could possibly ever 17 get I would think. I'm not trying to be 18 argumentative; I'm just trying -- well, maybe I am.
19 MR. MADNI: When we started on the 20 process of developing the design criteria for 21 advanced reactors, we started with the GDC and we 22 developed these technology specific criteria and we 23 also left one for design and technology inclusive 24 criteria. So what I'm saying is that lets the 25 designer, whoever he is, come up and develop his own NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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116 1 PDC's based on the GDC that just says we develop 2 technology specific criteria for our reg guide. They 3 can come up and develop their own PDC's from the GDC.
4 MEMBER KIRCHNER: You are actually, 5 though -- you weren't here earlier -- my point, I'll 6 repeat, is that you've fallen into the trap of 7 actually almost writing the PDC's for the applicant.
8 And it seems to be especially on the issue of 9 containment, or confinement, whichever you're going 10 to call it -- for example, let me read to you what 11 you have for the MHTGR. A reactor functional 12 containment consisting of multiple barriers, internal 13 or external to the reactor and its cooling system --
14 well, I mean, that sounds like a LWR. I know where 15 they're going, you know where they're going; they're 16 going to keep the fuel or primary barrier and they're 17 going to put the emphasis there because that's 18 foundational to that design approach. But if you go 19 back to your ARDC, I think from a policy standpoint, 20 that and the second paragraph of SFR16 are probably 21 something in that order would then pave the way for 22 doing the functional containment that's based on 23 performance and dose assessment, mechanistic source 24 terms, et cetera, and propagating that and seeing if 25 the health and safety of the public is protected.
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117 1 But I don't think these -- now I'm being 2 too repetitive -- these don't help, I don't think.
3 They just interject multiple definitions of what 4 containment is.
5 MR. MADNI: Well, if you look at SECY 6 9309, 092 or 093, then there you see the commission's 7 view of the containment. And they felt that pressure 8 retention is what we need. And so they approved, 9 actually, this kind of approach for the definition of 10 the containment for SFR.
11 MEMBER KIRCHNER: Well, if you say as you 12 have in the ARDC and we can argue what "essentially 13 leak-tight" is, but the idea of having a leak-tight 14 barrier is a pressure holding barrier, whether it's 15 confinement or containment as we know it with LWR's.
16 MR. MADNI: Well --
17 MEMBER KIRCHNER: I'm trying to push you 18 down the road because you're going to have to, at 19 some point, come back when you address that item under 20 Strategy 5, and it's a double whammy because you want 21 to go down the road -- you're going to shrink the 22 EPZ's -- you can do it two ways, right; you can say 23 precedent for the HTGR, Fort Saint Vrain had a 5-mile 24 barrier. Or we're going to do a mechanistic source 25 term, and that's going to be the basis for determining NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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118 1 EPC. And then that mechanistic source term is going 2 to be dependent on a functional containment 3 performance, right. So why not lay the groundwork 4 to go there, because that's where I think we want to 5 go?
6 MS. CUBBAGE: So this is Amy Cubbage from 7 the staff. I don't think we have any disagreement 8 with your concept that we need to move towards a more 9 performance-based approach across the board for 10 functional containment. We just don't want to get 11 ahead of the commission. We have explicitly weighed 12 in, in the past on gas reactor functional 13 containment, they have not in other areas. So we 14 just want to get that cleared up before we could go 15 forward.
16 CHAIRMAN BLEY: But it almost seems that 17 if you're going to keep Appendices B and C, which I'm 18 sure you're going to, that at least in this area it 19 would be prudent or wise to something very simple 20 here while you await the commission's decision -- I 21 assume you're already laying out how you think this 22 would go given if the Commission goes in the direction 23 of functional containment. But just use the GDC's 24 and apply them for your design and live with that, 25 instead of putting this placeholder in here that you NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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119 1 think you're going to wipe out and adds confusion at 2 this time.
3 MR. MADNI: Which one of the 4 placeholders?
5 MS. CUBBAGE: I think the --
6 MR. MADNI: Okay, so we can rethink that.
7 MS. CUBBAGE: No, wait a second. We 8 appreciate your view on that and we understand; 9 however, industry, Department of Energy, everybody 10 wants us to proceed with this to provide a starting 11 point for them to work towards. If they want to 12 propose something that's more performance-based or in 13 a different direction when they develop their site-14 specific replace, specific PDC's, they can do that, 15 but they are looking for us to put this out in its 16 current form.
17 MS. MAZZA: Also, I would like to point 18 out that our general counsel did not, they did not 19 specifically want us to change that ARDC until this 20 policy decision was made. So did not want to get 21 ahead of the policy.
22 CHAIRMAN BLEY: I was not suggesting 23 that; I was suggesting you live with that instead 24 of the others. But Walt's convincing me more and 25 more that if you keep this approach, you somehow have NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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120 1 to, at least in crucial places like this, define what 2 the design is. You've built this, too.
3 Go ahead.
4 MR. MADNI: Okay, so coming back to the 5 -- let's see, this was ARDC --
6 PARTICIPANT: First part of the comment.
7 MR. MADNI: Okay. All right, so the ACRS 8 letter noted that the phrase "essentially leak-tight" 9 is not adequately defined. This phrase is used in 10 the current GDC16 from MCFR Part 50 Appendix A and 11 10CFR Part 50 Appendix J, defines the testing 12 requirements for the "essentially leak-tight" 13 barrier. So the phrase has been taken directly from 14 the Court of Federal Regulations. So that's an 15 answer to the concern that the "essentially leak-16 tight" is not adequately defined.
17 Now we move to --
18 CHAIRMAN BLEY: I think -- I'm sorry, we 19 just had a little discussion -- you suggested that 20 the language is used in legal documents. A lot of 21 undefined language is used in legal documents off and 22 on purpose. Here we were saying from a technical 23 point of view that phrase is not defined. And were 24 you saying it is defined somewhere or were you just 25 saying it's used in legal document?
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121 1 MR. MADNI: It's defined somewhere.
2 It's like at least .1 percent every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or 3 something like that.
4 CHAIRMAN BLEY: Where is that defined?
5 MR. MADNI: I have to look that up.
6 CHAIRMAN BLEY: Okay. You ought to 7 refer to it, anyway.
8 MEMBER KIRCHNER: That kind of falls 9 under this area if you're going to provide some 10 definitions, that'd probably work.
11 MR. MADNI: If you look at Appendix J it 12 defines for multiple tests to verify the "essential 13 leak-tightness" of the containment. So Appendix J 14 is many pages.
15 MEMBER KIRCHNER: I don't think that's 16 referred to in your rationale, is it?
17 MR. MADNI: Let's see --
18 MEMBER KIRCHNER: No, I don't -- take a 19 look. Don't reply to that on the fly here. I don't 20 think it's in the rationale, at least not in --
21 MR. MADNI: It should be, but we'll check 22 it.
23 MEMBER KIRCHNER: Okay, thank you.
24 MR. MADNI: Okay, so if there are no 25 questions on this slide, we'll go to the next one.
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122 1 This slide shows the NRC language for 2 SFR-DC16. A reactor containment consisting of a low 3 leakage pressure retaining structure surrounding the 4 reactor and its primary cooling system shall be 5 provided to control the release of radioactivity to 6 the environment and to ensure that the reactor 7 containment design condition is important to safety 8 and not exceeded for as long as postulated accidents 9 and conditions require. So here the term "high 10 strength" has been removed to allow flexibility in 11 the criteria for new, innovative designs that may not 12 require a high-strength containment. So that's the 13 reason why high-strength was removed from the 14 definition and the criteria.
15 MEMBER SKILLMAN: Will the staff be 16 comfortable if an applicant comes in with a tin shed?
17 Yes or no?
18 MR. MADNI: Well, it has to fulfill the 19 requirements.
20 MEMBER SKILLMAN: So a tin shed is okay 21 as long as it fulfills the requirements?
22 MR. MADNI: But it should be pressure 23 retaining.
24 MEMBER SKILLMAN: Oh, really?
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123 1 strength part to allow for innovative designs, but 2 we've maintained the pressure retaining quality. If 3 the tin shed can retain pressure -- but of course the 4 tin shed will have to fulfill some other requirements 5 as well. So I can't say about the tin shed. But I 6 can tell you this, it has to be pressure retained.
7 MEMBER SKILLMAN: You know, T-I-N, S-H-8 E-D. Okay, I got it.
9 MEMBER KIRCHNER: So may I jump in here?
10 How did the high strength get in there to 11 begin with?
12 MR. MADNI: It has been used commonly for 13 SFR type containments.
14 MEMBER KIRCHNER: Well, that's the 15 applicant's words, but your GDC doesn't contain 16 anything about high strength for the advanced 17 reactors.
18 MR. MADNI: For the advanced reactors?
19 MEMBER KIRCHNER: Your advanced reactor 20 containment design criterion is the same as the GDC.
21 MR. MADNI: Yes, the advanced reactor is 22 technology inclusive. We are talking about 23 technology specific slide here. This is not 24 technology inclusive, it's technology specific for 25 SFR.
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124 1 MEMBER KIRCHNER: So what I'm confused 2 is how did high strength get in there to begin with, 3 and then why was it struck?
4 MR. MADNI: Well, the reason high-5 strength got in is because in sodium fast reactors 6 you have very strong temperature gradients across the 7 vessel. For example, compared with 30 degree rise 8 in temperature for the reactor core in LWR's, you 9 have 150 degrees because sodium has such high 10 conductivity and also very high temperatures because 11 it has a very high boiling point. So you're talking 12 about large temperature gradients; if you don't have 13 a high-strength containment, you may have some 14 problems.
15 MEMBER KIRCHNER: But you're proposing 16 to delete it?
17 MR. MADNI: Whether we delete it just to 18 allow for new design, that does not mean we cannot -
19 - we will evaluate of course the applicant -- if 20 there's some problems with strength, then we will 21 bring that. By removing it, it doesn't mean we 22 cannot use it in evaluating an applicant.
23 MEMBER RICCARDELLA: As a metallurgy 24 structural engineer, the words high-strength is very 25 ambiguous.
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125 1 MEMBER KIRCHNER: I know; I agree. I 2 don't think it should be there.
3 MEMBER MARCH-LEUBA: Well, I don't know.
4 Have you considered the effect of missiles, like 5 hurricane/tornado, because the containment typically 6 contains all those.
7 MR. MADNI: Okay, these containments are 8 generally underground.
9 MEMBER MARCH-LEUBA: Again, you're 10 assuming missiles --
11 (Simultaneous speaking.)
12 MR. SEGALA: Those are other 13 requirements, so if they need a structure to protect 14 the safe-related equipment from missiles or flooding 15 or whatever, they're going to have to have a structure 16 that can meet those requirements.
17 MEMBER CORRADINI: Can you remind us 18 where that is for those of us that are struggling to 19 find your other requirements?
20 MS. MAZZA: No. 2, GDC-2.
21 MEMBER CORRADINI: We were in the teens.
22 Thank you.
23 MR. MADNI: Okay, so the term "low 24 leakage" as is mentioned in the SFR-DC content has 25 been used in the SFR-DC content. It is addressed NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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126 1 here in the second bullet and on the next slide as 2 well. So the phrase in the bullet that is tying in 3 the low leakage with performance-based criterion 4 related to leakage. So it says in the first bullet, 5 "The reactor containment design conditions important 6 to safety are not exceeded." This one refers to the 7 performance-based criterion is restricting the 8 release due to leakage.
9 Indicated in the second bullet which is 10 "The containment leakage shall be restricted to be 11 less than that needed to meet the acceptable on-site 12 and off-site dose consequence limits as specified in 13 CFR 50.34 for postulated accidents. So that's where 14 the low leakage is defined in terms of a performance-15 based criteria related to leakage.
16 MEMBER KIRCHNER: Now again, I would go 17 back and challenge you; I think your advanced reactor 18 criterion for No. 16 is better than this one. You 19 are once again presuming it's a pool-type system and 20 everything will be contained. We just talked about 21 it may be cited underground, but what if I want to go 22 the LOOP? And we have loop systems, FFTF, so why are 23 you saying it's surrounding the reactor and its 24 primary coolant system?
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127 1 Idaho National Lab. Just maybe a little bit of 2 background on this topic because I know it's come up 3 a couple of times through the discussion this 4 morning, but back in 2013 when we developed the 5 proposals in conjunction with industry and with input 6 from DOE, we put out a call for design information 7 and got it out 15 or so responses from industry in 8 various level of detail. We used that information 9 to form the content of the proposal that the NRC staff 10 then reviewed. And to your point of this being 11 trapped in or being clear on what those proposals 12 were based on; because we had additional information 13 available to us on those responses, we actually wrote 14 some summary information in the proposal report that 15 went to NRC that described the key aspects of both 16 the SFR and the modular HTGR, so the criteria were 17 built around that.
18 MEMBER KIRCHNER: Okay.
19 MR. KINSEY: So those -- that may have 20 gotten lost in the chain of communication along the 21 way here, but there are some summary bases for why 22 the proposals were made as they were and why NRC has 23 retained a lot of that structure along the way that's 24 not reflected in the reg guide. So just to give you 25 that background.
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128 1 MEMBER KIRCHNER: Well, I'm still going 2 to be a thorn into your blanket today. I did an 3 independent review when I was at Los Alamos at the 4 prison reactor; this was back in the 90's when you 5 had the staff doing its -- what do you call it --
6 Preliminary Safety Evaluation Report. So we did an 7 independent technical review of both. The HTGR 8 modulates TGR and the prison concept. So when you 9 write something like this, you're presuming that 10 primarily the design you'd be reviewing, but when you 11 do this --
12 MR. MADNI: What presumption is there?
13 MEMBER KIRCHNER: That it's probably a 14 prison-like design.
15 MR. MADNI: No, not necessarily.
16 MEMBER KIRCHNER: Okay, not necessarily.
17 When you -- some of those designs, and I don't think 18 this is proprietary, have ECCS systems that are air-19 cooled.
20 MR. MADNI: We don't have ECCS system in 21 SFR.
22 MEMBER KIRCHNER: The equivalent; you 23 have the K heat removals.
24 MR. MADNI: There's no injection either.
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129 1 about a R-vac system, back in prison it was called a 2 R-vac which is essentially the RCCS for the gas-3 cooled reactor.
4 MR. MADNI: Yes.
5 MEMBER KIRCHNER: Right, exactly. And 6 that comes outside of containment.
7 CHAIRMAN BLEY: Well, I --
8 MEMBER KIRCHNER: Now we're getting into 9 specific design and also it's kind of quasi -- not 10 even qualitative review -- of a design approach. But 11 I don't think you want to write this like this; I 12 think you should fall back on the GDC.
13 CHAIRMAN BLEY: I'm going to interrupt 14 this discussion here.
15 MEMBER KIRCHNER: That's my opinion.
16 CHAIRMAN BLEY: I think several people 17 have made points on this and I think we got to go on 18 because we don't have a whole lot of time.
19 MEMBER KIRCHNER: Okay.
20 MR. MADNI: Okay, so next slide.
21 This slide addresses the rationale for 22 the use of the term "low leakage" and it defines the 23 Commission approved the staff's recommendation to 24 restrict the leakage of the containment to be less 25 than that needed to meet the acceptable on-site and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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130 1 off-site dose consequence limits in SECY 93-092.
2 Therefore, the Commission agreed that the containment 3 leakage for advanced reactors similar to a prison 4 should not be required to meet the "essentially leak-5 tight" statement in GDC-16, and that's from the NUREG 6 3068 which is the PSCR from the NRC. So this has the 7 commission's blessings and I don't think we are quite 8 trapped here yet.
9 Okay, so this basically addresses the 10 HTGR's comment related to the definition of low 11 leakage. And also if you look at the first, if you 12 look at Enclosure 1 Section A of SECY 93-092, it talks 13 about satisfying 10 CFR Part 100 dose limits and Part 14 100 the first 10 CFR 50.34 which is the same as the 15 previous slide.
16 Now, the other thing I wanted to mention 17 was that public comments were generally supportive of 18 this language, and hence there's a need to specify 19 performance-based criterion and the expectation will 20 be that the applicant will analyze what he assumes is 21 taking place in the containment and provide a design 22 with a low-leakage rate that meets Bullet 2 of SFR-23 DC16 which is the previous slide, which the staff 24 will review for adequacy in meeting SFR-DC16. And 25 currently SFR containment designs being considered NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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131 1 are varied; hence providing a prescriptive 2 requirement such as that contained in Appendix J of 3 10CFR 50 would prove difficult. So that's the 4 reasons for the performance-based, because you have 5 radioactive for designs; we're not fixing ourselves 6 to prison wall use, we are taking care of radioactive 7 designs.
8 MEMBER KIRCHNER: Will you repeat what 9 you said? You don't want to use an Appendix J like 10 approach because it's not inclusive?
11 MR. MADNI: Yes, because that's 12 prescriptive.
13 MEMBER KIRCHNER: No, I'm not referring 14 to the details of it, but you don't want to use an 15 Appendix J approach just because it's varied, which 16 you seem to infer that you could not inspect it.
17 MR. MADNI: Well, here it is just that 18 you want the applicant to move that from what is the 19 objective of the low-leakage containment, which is to 20 meet 10CFR Part 50.34 requirements and work backwards 21 to see what should be the conditions in the 22 containment. We cannot prescribe for them; we just 23 give them performance-based criteria which they 24 should satisfy.
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132 1 six more slides in this area and I think we just got 2 to go through them. We may bring up some areas again 3 at the full committee meeting and you may see 4 something like this later.
5 MR. MADNI: Okay, so the next slide, we 6 move now to MHTGR-DC16. This slide shows the NRC 7 language for MHTGR-DC16 content, "A Reactor 8 functional containment consists of multiple barriers 9 external to the reactor and its cooling system shall 10 be provided to control the release of radioactivity 11 to the environment and to ensure that the functional 12 containment design condition reported as safety not 13 exceeded as long as postulated accident condition 14 required. So you might notice that this is something 15 that is really for a variety of advanced reactor 16 designs that you have this kind of performance-based 17 criteria.
18 So the NRC language for MHTGR-DC16 as 19 shown here and published in the reg guide is the same 20 as the DOE proposal, many comments were received 21 supporting this language. And here "functional 22 containment design condition and important to safety" 23 refers to the performance-based criterion restricting 24 release of products to the environment. And that you 25 can see in the next slide.
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133 1 This slide shows the NRC rationale for 2 adaptations to GDC. And the first bullet, the term 3 "functional containment" is applicable to non-LWR's 4 without a pressure retaining containment structure.
5 The second bullet; the functional 6 containment can be defined as a barrier or set of 7 values taken together that effectively limit the 8 physical transport and the environment across a full 9 range of AAO's, non-operating condition AAO's and 10 accident conditions.
11 And the third bullet is the MHTGR 12 functional containment safety design objectives, is 13 to meet 10CFR 50.34 dose requirements at the plant, 14 exclusionary boundary and off-site with margins.
15 So the objective is typically achieved 16 without taking credit for the radio nuclei 17 characteristics offered by the radioactive building 18 which is the fifth barrier. So we just use the four 19 barriers, three are in the fuel and then the high-20 pressure.
21 Next we continue with NRC rationale for 22 adaptation to GDC. The NRC staff has brought the 23 issue of functional containment to the Commission and 24 the Commission has found it generally acceptable as 25 indicated in -- sorry, I'm SECY 93-092 and SECY 03-NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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134 1 0047 -- in the SRM to SECY 03-0047 the Commission 2 instructed the staff to develop performance 3 requirements and criteria working closely with 4 industry experts; for example, designers, et cetera, 5 and other stakeholders regarding options in this area 6 taking into account such features as core, fuel and 7 cooling system design, and directed the staff to 8 submit options and recommendations to the Commission 9 for policy decision.
10 So the SECY paper that was to discuss 11 functional containment and performance requirements 12 mentioned by Jan earlier will be technology inclusive 13 and will address topics and functions containment 14 such as the use of SARRDL, and that's where it stands 15 at present. The status is that we are still working 16 on it and the reg guide may be modified to incorporate 17 the Commission's position following the SECY paper.
18 So once that is done, then the Commission rules on 19 it, we can modify our reg guide accordingly.
20 The next few slides will address the last 21 sentence of the ACRS comment on containment, which is 22 an examination for the possibility of reactor 23 pressure boundary failure to inducing containment 24 failures should be included explicitly. So we start 25 first with a new design criteria for MHTGR; since the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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135 1 reactor building is not relied upon as part of the 2 functional containment to meet the off-site dose 3 requirements, the reactor building design base is not 4 included in MHTGR-DC16 which is containment design.
5 Instead, the requirements regarding its performance 6 are addressed by a new MHTGR criterion 71 which deals 7 with reactor building design basis and 72 provision 8 for periodic reactor building inspection.
9 So this slide shows MHTGR-DC71 which is 10 reactor building design basis. So the first bullet 11 is the design of the reactor building shall be such 12 that during postulated accidents it structurally 13 protects the geometry for passive removal of residual 14 heat from reactor core for the ultimate heat sink and 15 provides a pathway for release of reactor helium from 16 the building in the event of depressurization 17 accidents.
18 And the second bullet; the reactor 19 building functions are to protect and maintain 20 passive cooling geometry -- this is part of the 21 rationale -- and to provide a pathway for release of 22 helium from building in case of line break in reactor 23 helium pressure boundary. These new criterion show 24 that these safety functions are provided. So here 25 the ACRS comment which I will repeat, in examination NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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136 1 of the possibility of reactor pressure boundary 2 failure to induce containment failure should be 3 included explicitly. So for a brief explanation, 4 brief explanation follows that radio nuclei retention 5 is within the fuel during normal operation with 6 relatively low inventory to the helium pressure 7 boundary. In the helium pressure boundary break 8 scenario, the reactor building is vented early when 9 the helium circulating activity is low. The reactor 10 building vent is closed laboring the transient when 11 the particle fuel reaches maximum temperatures.
12 Early venting ensures that the reactor building will 13 not be damaged from helium pressure boundary rupture.
14 So this is kind of an explanation in response to the 15 ACRS comment.
16 MEMBER KIRCHNER: If this is the way you 17 proceed, I'm just sitting here thinking, well I have 18 a LWR, the fuel's pretty good, circulating inventory 19 is low. So during a B-20 (Simultaneous speaking.)
21 MR. MADNI: Well, here --
22 MEMBER POWERS: There are a lot of 23 proposals to do that.
24 MEMBER KIRCHNER: I know.
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137 1 the fuel and the clad, and then you have the reactor 2 vessel. And the containment is considered the 3 ultimate barrier, everything goes into the 4 containment. But here they're talking about a period 5 of time when the radioactivity is confined within the 6 fuel, the first three barriers within the fuel. And 7 so --
8 MEMBER KIRCHNER: I know all this; I know 9 they have to vent it because to build a pressure 10 resilient building for the helium blow-down would be 11 prohibitively expensive. I'm just remarking that 12 your logic would suggest then LWR's would vent too, 13 because you don't get to the fuel high clad 14 temperature until well after the blow-down event. In 15 fact, the blow-down cools the fuel.
16 MR. MADNI: You probably could do that.
17 And that's probably one of the things that is under 18 consideration; maybe there's division in there, you 19 need filter venting or non-filter venting. There's 20 a (Simultaneous speaking.)
21 MEMBER KIRCHNER: Is that the thinking, 22 or you'll wait and see how the fuel qualification 23 program goes and with operating experience backed it 24 to do a filter vent?
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138 1 into it because we are focused here on advanced 2 reactors. I'm getting to the -- discussing 3 lightwater reactors.
4 MEMBER KIRCHNER: I don't want to discuss 5 LWR's; I want to discuss the gas-cooled reactor. Are 6 you providing an advance for a filtered vent or just 7 an uncontrolled vent?
8 MR. MADNI: Okay, that's a good question.
9 Because imagine the high-pressure helium pressure 10 boundary; if that fails, then you have a tremendous 11 off coming out and if you try to filter it, the 12 filters will blow out.
13 MEMBER KIRCHNER: I know that.
14 MR. MADNI: So therefore, this is a lever 15 that opens and allows this puff to go out, and then 16 closes.
17 MEMBER KIRCHNER: So what if you let the 18 puff go through a pool of water?
19 MR. MADNI: But this doesn't have any 20 radioactivity, let it go out.
21 MEMBER KIRCHNER: You don't know until 22 you've got operating expenses in the reactor.
23 MR. MADNI: That's closely monitored.
24 The helium LOOP is constantly monitored for plateout 25 and for activity.
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139 1 MEMBER KIRCHNER: So, what I think it 2 begs though is an associated requirement about the 3 quality of the fuel and the circulating inventory.
4 MR. MADNI: Yes, fuel qualification 5 program has to be there.
6 MEMBER KIRCHNER: Okay, I've made my 7 point. Thank you.
8 MR. MADNI: Okay, the next one is MHTGR 9 72; this slide addresses -- it reinforces the 10 function of the reactor building. The reactor, the 11 BC content is reactor building shall be designed to 12 permit, Number 1, appropriate periodic inspection of 13 all important structural areas in the 14 depressurization pathway. And Number 2, an 15 appropriate surveillance program.
16 And then the second bullet; this newly 17 established criterion on periodic inspection and 18 surveillance provides assurance that the reactor 19 building will perform its safety functions of 20 protecting and maintaining the configuration needed 21 for passive cooling and providing a pathway for 22 helium depressurization vents.
23 And that is the end of my presentation, 24 so if you have any questions.
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140 1 going to Slide No. 48. So that concludes our 2 presentations on the ACRS comments. For the public 3 comments we received 127 comments from ten different 4 stakeholders and of the 127 comments we agree with 64 5 of them and made appropriate changes to the reg guide.
6 The most significant comments were discussed today 7 and during the August and November meetings. Also, 8 I note that Derek Widmayer had provided a summary of 9 the significant comments to the ACRS, so you have 10 that ahead of this meeting. But we --
11 CHAIRMAN BLEY: Was that all -- that was 12 all the comments, is that right?
13 MS. MAZZA: Yes, so we'd be happy to talk 14 about anything that we didn't discuss at this time.
15 CHAIRMAN BLEY: If I didn't miss 16 something skimming through there, all of the public 17 comments were either from some member of industry or 18 from the DOE vote, is that right?
19 MS. MAZZA: There was also some other 20 individuals that did comment.
21 CHAIRMAN BLEY: Were they in the 22 document?
23 MS. MAZZA: Yes, they were in there.
24 CHAIRMAN BLEY: I somehow missed them as 25 I read through it.
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141 1 MS. MAZZA: If you look at the very first 2 page of the, all the different comments.
3 CHAIRMAN BLEY: Oh, the different ones.
4 Okay, thanks.
5 MS. MAZZA: So if there's any other 6 specific comments that you all would like to discuss, 7 we'd be glad to do that now.
8 MR. KINSEY: And a point of clarification 9 -- this is Jim Kinsey -- the DOE comments included 10 input from Oak Ridge and Idaho National Lab was for 11 that team.
12 CHAIRMAN BLEY: Thanks.
13 MEMBER REMPE: So when I was looking 14 through them, several individuals really were 15 asking/begging for security-related information and 16 the response from the staff was not helpful, and I'm 17 wondering if that's going to continue?
18 MS. MAZZA: Well, for this reg guide 19 that's a separate effort, so we're not going to 20 address that in this reg guide but we are working on 21 security issues.
22 MEMBER REMPE: Okay, and I guess I didn't 23 see how quickly that would happen in the responses?
24 It's underway and --?
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142 1 SECY paper that's on its way. Anyone else?
2 So next steps, we believe we addressed 3 all the public comments --
4 MEMBER BROWN: Oh, I'm sorry --
5 MS. MAZZA: Oh.
6 MEMBER BROWN: Yes, I was looking for my 7 comments. Trying to find which one it was now; I 8 thought I just found it.
9 MEMBER REMPE: Well, while you're 10 waiting, yes the response says it's on hold is what 11 I saw in the response on security. So again, I think 12 it's good to make sure those folks know.
13 MS. MAZZA: Okay, thank you.
14 MR. SEGALA: Well, there's two things as 15 part of the development of the advanced reactor 16 design criteria; we also developed security design 17 considerations. Those were originally one effort and 18 then they were split apart. We issued what we call 19 draft security design considerations for public 20 comment. We got a few comments, but we've put that 21 on hold because we're working on this security, SECY 22 paper on physical security. So we're going to go 23 forward with the SECY paper, and then after that we 24 get direction from the Commission; we're going to go 25 back and look at whether we need to do anything with NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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143 1 the security design consideration document that we 2 have. So that's kind of a piece that's on hold while 3 we're -- it's all security but they were kind of two 4 effort.
5 MEMBER REMPE: Thank you.
6 MEMBER BROWN: Thank you, I found it.
7 This was back on ARDC 26 and there was a NEI comment 8 which you all responded to, that they wanted to use 9 anticipated operational occurrences and postulated 10 accidents instead of design basis events in terms of 11 that second criteria in 26. And you all agreed with 12 that. And I guess I lost the bubble on why design 13 basis events had disappeared from the criteria that 14 we look at as opposed to just AOO's?
15 MS. MAZZA: So I don't think Jeff's still 16 here but I believe it was a consistency issue that we 17 didn't use design basis events elsewhere in the 18 design criteria.
19 MEMBER BROWN: In the current design 20 criteria?
21 MS. MAZZA: So in the reg guide and --
22 MEMBER BROWN: I got the flavor that in 23 the original design, the GDC's, as they are presently 24 stated, and I was trying to find that they actually 25 refer to design basis events. I thought that was in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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144 1 there, but I might have missed that.
2 MS. MAZZA: I don't think so. No, I 3 don't --
4 CHAIRMAN BLEY: Do they have accidents?
5 MS. MAZZA: Throughout the design 6 criteria it's normal ops, AOO's and postulated 7 accidents, and that's -- really the comment was a 8 consistency issue.
9 MEMBER BROWN: But it was relative to the 10 second means of I guess shutting down, which implied, 11 it said "The industry suggested reactors with 12 inherent or passive shutdown capability fundamental 13 to the physics of the system can justify that a second 14 means would be superfluous." I guess I'm just trying 15 to mush around why a second means of reactivity 16 control would be superfluous? And you all imply --
17 you did not agree with that, but you did then agree 18 with a second concern relative to using AOO's and 19 postulated accidents instead of design basis, so --
20 CHAIRMAN BLEY: Maybe you could check 21 with Jeff and address this at our full committee 22 meeting.
23 MEMBER BROWN: Jeff is not here and I'm 24 just making that comment during the last part of the 25 meeting. I apologize for that.
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145 1 MS. MAZZA: Okay. Any other questions 2 on the public comments?
3 So our next steps, we believe we've 4 addressed public comments satisfactory and we're 5 looking forward to ACRS feedback. We think.
6 (Laughter.)
7 CHAIRMAN BLEY: I had a question. We're 8 going to have a full committee meeting in about a 9 month, almost exactly a month. If you -- are you 10 going to get us any sort of revision, at least a week 11 or a little bit before that full committee meeting on 12 things you're actually making changes in?
13 MS. MAZZA: Okay.
14 CHAIRMAN BLEY: That would be helpful.
15 And if it were received in a way we could see what 16 was changed --
17 MS. MAZZA: Right. So right now you have 18 a redline strikeout from the last meeting until now, 19 so if I wipe that all out and --
20 CHAIRMAN BLEY: It's the new redline 21 strikeout.
22 MS. MAZZA: Would that be acceptable?
23 CHAIRMAN BLEY: Yes, I think -- I don't 24 know how many changes you're going to make, but I 25 think two weeks would be nice, a week would be enough NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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146 1 for us to look through and see what the changes were, 2 and then discuss them when you're there. Since 3 almost the full committee was here at this meeting, 4 I think you ought to focus at the next meeting on 5 just a brief overview because it is a public 6 meeting, full committee meeting, and then on the 7 things that are new that we can consider before we go 8 into our letter-writing session.
9 MS. MAZZA: Okay.
10 CHAIRMAN BLEY: I don't know how much 11 time they're going to give us, probably two hours, so 12 consider it two hours unless you hear from Derrick.
13 MS. MAZZA: Okay.
14 CHAIRMAN BLEY: Or if you think you don't 15 need that much through Derrick. Any last comments 16 on what we've just seen?
17 At this time I guess I'll get public 18 comments and then go around the room.
19 We want to open the line for public 20 comments, and while we wait for that; in the meeting 21 room here if anyone wants to make a comment, please 22 come to the microphone, identify yourself and make a 23 comment.
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147 1 yourself and make your comment.
2 It's suspiciously quiet. Theron, do we 3 have an open line?
4 It's really quiet. We're going to wait 5 a minute for this one.
6 Hello? I think your line's open now.
7 If there's anyone on the line who would like to make 8 a comment, please identify yourself and make your 9 comment.
10 I guess there's no one there. We can 11 close the line again.
12 At this time I'd like to go around the 13 room, but before I do that, if any members have a 14 particular point you'd like to see addressed at the 15 full committee meeting, you might raise them here.
16 Your overall views are good. And if you have any 17 particular comments you would like to have considered 18 for inclusion in our letter, please email them to me 19 or drop off a note.
20 Joy, can I start with you?
21 Oh, I see Vesna but I started with Joy 22 because that's the way I wrote down all the names.
23 And Vesna will get the distinct honor of being last.
24 MEMBER REMPE: Sorry. Sure. Okay, so 25 first off I wanted to just emphasize because we didn't NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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148 1 during the meeting, that I did look through all of 2 those comments and your responses back and I thought 3 there were a lot of good comments and many times --
4 well, several times -- the commenters said, "Hey, 5 appreciate this. You did a good job." And then also 6 in response back to the comment about the design 7 information, sometimes you pointed out, "Hey, you 8 guys are assuming something about a design that 9 there's other aspects of the other designs that might 10 occur, so we need to be more general." And so I do 11 think you are cognizant of some of the concerns that 12 Walt raised.
13 On the other hand, though, I think that 14 it would be good in the introductory remark where you 15 talk about that you use the DOE document, that you do 16 emphasize, as Walt continued to emphasize during the 17 meeting, that you relied on this design information 18 that Jim Kinsey said, because I think that would 19 alleviate a lot of discussion we had today and say 20 you realize that some of these other gas-filled 21 reactors may not, or sodium reactors may not 22 accommodate what was discussed in this DOE document.
23 But so you'll need to justify this, but it just helps 24 craft things 20 years from now we go back and do 25 another one of these advanced reactor initiatives.
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149 1 Things I'd really like to see addressed 2 in the draft document, that we mentioned today, was 3 the need to have a definition of terms and design 4 information. But also then, I'd like to push back a 5 little bit more on what Walt said about the need for 6 SAFDL versus SARR -- whatever it is, the acronym is 7 -- but I think with the pebble bed reactor that it 8 might be easier to go with this other limit because 9 of the fact that if it's a time temperature criterion, 10 it might be more difficult for some designers to have 11 to monitor what the pebble's doing. So I guess I'm 12 on the other side of the fence on that one and I just 13 thought I'd mention it.
14 Next.
15 CHAIRMAN BLEY: Go ahead, Charlie.
16 MEMBER BROWN: Okay, just two items and 17 I don't know where they'll end up fitting in, whether 18 they're -- I'd just like to firmly resolve the issue 19 on ARDC 26 relative to the definition of safe shutdown 20 which we discussed extensively and whether any change 21 will be made. I would like to see that discussed 22 again in the full committee if there was nothing going 23 to be done, or what you're going to do if you are 24 going to do something.
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150 1 reactor containment thing; on containment for all 2 the, whether technology neutral or technology 3 specific, it seems to me that containment principles 4 are that you don't irradiate the public or the site 5 people. And that second paragraph in the SFR-DC was 6 a nice definition of let's take care, what's the 7 bottom line high-level principle that's needed for 8 containments, for any reactor that's designed. So I 9 guess have it addressed in the full committee meeting 10 and if you're not going to do anything with that, 11 then hopefully get the committee to agree to say 12 something in their letter.
13 MEMBER KIRCHNER: Thanks. Well --
14 CHAIRMAN BLEY: Well, I said enough.
15 (Laughter.)
16 So I thank the staff for all their 17 effort, and I know there's a lot of effort in the 18 back benches here. So I thank you all for your 19 effort. And I didn't mean to just trash everything, 20 but I actually did mean to say I think you've done a 21 good job on the event, the actual design criteria.
22 So thank you.
23 MEMBER MARCH-LUEBA: I want to agree with 24 what Walt said during monthly meeting; during the 25 meeting I kept turning my green light on to say NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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151 1 something and he would cover whatever I was going to 2 say. So I would agree with the last one. Next, 3 Pete.
4 CHAIRMAN BLEY: Oh, Pete's gone. That's 5 right. John?
6 MEMBER STETKAR: Me too with Walt.
7 CHAIRMAN BLEY: Mike's gone. Dana?
8 MEMBER POWERS: No comment. Thank you, 9 though, for the comment.
10 CHAIRMAN BLEY: Harold?
11 MEMBER RAY: Yes, I guess I'm meaning by 12 what I'm going to say to underscore at least part of 13 what Walt said, but I want to say it myself; I think 14 we all should expect regulatory requirements to be as 15 generic as possible. And where the requirements are 16 based on a particular set of assumptions or 17 understanding/concerning a design, they need to be 18 explicit and specific, not simply implicit and based 19 on our current understanding of what that technology 20 will look like in the future.
21 CHAIRMAN BLEY: Thank you, Harold.
22 Matt's gone. Ron?
23 MEMBER BALLINGER: I guess I'm on board 24 with "Mr. I've Said Enough," but I'd like to --
25 CHAIRMAN BLEY: Not quite.
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152 1 (Laughter.)
2 MEMBER BALLINGER: -- knock down, go down 3 the original sources and the definitions and where 4 they are and how they're defined are very obscure.
5 I mean, believe it or not "essentially leak type" is 6 not used in 10CFR 50 except to say "essentially leak 7 type." Appendix J does not define -- it defines the 8 leakage criteria, the limit, but it doesn't equate it 9 to "essentially leak type." And as far as GDC-26 or 10 whatever that one is, I've looked at every document 11 that I could find except for the URD which is like 12 900 pages long, which I haven't read. But nowhere 13 does it say -- does the word "sub-critical" appear in 14 any of the documents, it's all thermally-based.
15 So I just, I'm not an expert in this area 16 but it would seem to me that some clear definition, 17 somebody said that, is appropriate for this. You've 18 got an opportunity to do it, but goodness gracious if 19 you need two PhD's and a law degree to go find out 20 where to connect all the dots, it probably shouldn't 21 be that way.
22 CHAIRMAN BLEY: Vesna?
23 MEMBER DIMITRIJEVIC: I thought maybe 24 you would finish.
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153 1 turn on your mic.
2 (Laughter.)
3 MEMBER DIMITRIJEVIC: Oh, okay. I mean, 4 this is the beginning for me. I'm learning all of 5 this. I mean, especially like the safety functions 6 and the important for safety function obviously.
7 It's very good to clean that. Also, I find that 8 confusing for sanction if you define that as being 9 shut down, it doesn't say we want to minimum reach 10 this condition, and what is the maximum? I mean, 11 that is all which we need, right, so why is it minimum 12 condition?
13 So I mean, this time clean terminology 14 would be helpful. Otherwise, that's all, I'm just 15 learning.
16 CHAIRMAN BLEY: Okay, thanks Vesna. And 17 our consultant, Steve. And you'll send me some 18 content.
19 MR. SHULTZ: I sure will. Thank you.
20 Just for here, I would like to agree with 21 Walt and with Harold. We started the discussion 22 indicating that with regard to the GDC's as they were 23 originally built, that they may apply to advanced 24 reactors and that certainly what they say and what 25 could be surmised. The process that was done there NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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154 1 with original GDC's was similar to what has been done 2 here; that is the general design criteria have been 3 proposed and then the industry has commented on how 4 they would like them to be because they're specific 5 designs that they want to move forward with. And I 6 think this has been a good approach to take a couple 7 of designs and demonstrate how the criteria would be 8 derived for the particular features.
9 What concerns me is when we make 10 statements about applicability of the design criteria 11 for the examples that are provided in a general sense 12 where we say if designs share common features with 13 the designs that have been proposed and the 14 Commission has provided discussion on exemption.
15 Then those designers may apply what's been determined 16 and decided. I think as Harold said, the designs are 17 expected to be different as we move forward. And I 18 think to suppose that decisions that were making with 19 regard to regulatory requirements and their 20 applicability have to be design specific, and that's 21 not just the staff's responsibility, but it's the 22 designer's responsibility to take the initiative to 23 identify specifically what needs to be done to 24 demonstrate that the design meets all the expected 25 regulation, and for the staff then to review that in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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155 1 course.
2 So that's what I would want to ensure 3 happen. And I've become concerned when it seems to 4 be suggested that the process is easy for a new design 5 or a new designer or even something that's very 6 similar. It really has to go through the rigors of 7 evaluation, and that starts with the proposal of the 8 applicant.
9 CHAIRMAN BLEY: Thank you. I would 10 certainly like to thank the staff for very good 11 discussions. I, too, think you've done a really good 12 job bringing this to this point. I'm going to add 13 to the chorus of agreeing with Walt; one way or 14 another, and the way Joy suggested is probably the 15 easiest way, just referring to the documents that you 16 use to -- I call them concepts rather than specific 17 designs because you don't -- you're not looking at 18 specific designs, you're looking at conceptual 19 designs. But referring to those so people know what 20 those Appendix B and C design criteria were aimed at 21 addressing, would be helpful now and invaluable in 22 the future when people want to use them for things 23 that aren't the same as you looked at, would be 24 important.
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156 1 committee meeting and to getting whatever revisions 2 you put together before then. If we can, as I said, 3 if we can get them at least a week ahead in a mark-4 up, I think we can deal with that. And that will be 5 helpful. And as soon as you can get the slides to 6 us, that'll help too.
7 I think we've covered everything.
8 Thanks so much to everyone who was here, and we are 9 adjourned.
10 (Whereupon, the above-entitled matter 11 went off the record at 12:21 p.m.)
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Non-Light Water Reactor Design Criteria Introduction and Overview of ACRS Interactions John Segala, Chief, Advanced Reactor and Policy Branch February 7, 2018
Vision and Strategy for Advanced Reactors Near-Term Implementation Action Plan Strategy 1 Strategy 2 Strategy 3 Strategy 4 Strategy 5 Strategy 6 Knowledge, Computer Flexible Review Industry Codes Technology- Communication Skills and Codes Processes and Standards Inclusive Policy Capacity Issues Identification/ Siting near ORNL Molten Assessment Regulatory ASME BPVC densely NRC DOE Salt Reactor of available Roadmap Sect. III Div. 5 populated Workshops Training tools Areas ANS Knowledge Prototype Standards Insurance and Periodic Management Guidance 20.1, 20.2, Liability Stakeholder 30.2, 54.1 Meetings Non-LWR Consequence Competency Design Non-LWR Based NRC DOE Modeling Criteria PRA Standard Security GAIN MOU Licensing Modernization EP for SMRs International Project: and ONTs Coordination
- LBE Selection
- Defense in Depth
- PRA Approach Functional
- SSC Safety Classification Containment Performance Criteria 2
2017 ACRS Interactions for Non-LWRs
- Vision and Strategy Staff Report: Near-Term Implementation Action Plans o 3/8/17 - Future Plant Designs Subcommittee o 3/9/17- Full Committee o 3/22/17 - ACRS Letter
- Non-LWR Design Criteria - Draft Regulatory Guide 1330 o 2/22/17 - Future Plant Designs Subcommittee o 3/9/17- Full Committee o 3/22/17 - ACRS Letter 3
2018 ACRS Interactions for Non-LWRs
- Non-LWR Design Criteria - Regulatory Guide 1.232 o 2/7/18 - Future Plant Designs Subcommittee o March 2018 - Full Committee
- Functional Containment Performance SECY Paper o 2/22/18 - Future Plant Designs Subcommittee o April 2018 - Full Committee
- Licensing Modernization Project o 6/19/2018 Future Plant Designs Subcommittee o 10/30/2018 Future Plant Designs Subcommittee o December 2018 - Full Committee
- EP Rule o 8/22/18 - Future Plant Designs Subcommittee o October 2018 - Full Committee 4
Background and Summary of Non-LWR Design Criteria Discussed with ACRS in 2017 Jan Mazza, Project Manager Advanced Reactor and Policy Branch February 7, 2018
Recent Progress on the Non-LWR Design Criteria RG
- 2-3-2017 DG -1330 Issued for 60 day public comment period
- 8-24-2017 Public meeting for staff interaction on public comments
- 11-1-2017 Additional Public Interaction on ARDC 17 and 26
- 1-15-2018 Draft Final RG 1.232 and Draft Public Comment Resolution Table issued for 2018 ACRS meetings
- 3-2018 Projected final RG issuance 6
Non-LWR Initiative Background
- In June 2013, DOE and NRC agreed to pursue a joint initiative to formulate guidance for developing principal design criteria (PDC) for non-light water reactor designers.
o NRC Regulations 10 CFR Part 50 Appendix A establish General Design Criteria (GDC) specific to LWRs and generally applicable to non-LWRs.
o Applicants must establish PDC based on the GDC (10 CFR Part 50.34(a)(3),10 CFR Part 52.47(a)(3), etc.).
7
Non-LWR Initiative Background cont.
- The general GDC in 10 CFR Part 50 Appendix A, establish the applicability of the GDC to both LWR and non-LWR designs:
These General Design Criteria establish minimum requirements for the principal design criteria for water-cooled nuclear power plants similar in design and location to plants for which construction permits have been issued by the Commission. The General Design Criteria are also considered to be generally applicable to other types of nuclear power units and are intended to provide guidance in establishing the principal design criteria for such other units.
8
Non-LWR Initiative Background cont.
- 10 CFR Part 50, Appendix A indicates that the GDC are guidance for non-LWRs. As such, non-LWR applicants would not need to request an exemption from the GDC when proposing PDC, which are derived from the GDC.
- The RG provides additional guidance for reactor designers and applicants of non-LWR designs for developing PDC.
9
Non-LWR Initiative Background cont.
- It is the responsibility of the applicant to:
o develop the PDC for its facility based on the design, using the GDC, non-LWR design criteria, or other design or technology specific criteria as needed.
o consider public safety matters and fundamental concepts, such as defense in depth, in the design of their specific facility and for identifying and satisfying necessary safety requirements o provide the PDC for the design and supporting information that justifies how the design meets the PDC submitted, and how the PDC demonstrate adequate assurance of safety.
o In instances where a GDC or non-LWR design criterion is not proposed, the designer/applicant must provide a basis and justify the omission from a safety perspective.
10
March 21, 2017 ACRS Letter
- Technology-Specific Licensing Basis Events
- Facilitate PRA in the design criteria
- Reactor Fuel Design Limits MHTGR-DC 10
- Containment ARDC, SFR-DC, & MHTGR-DC 16
- Electric Power Systems ARDC 17
- Reactivity Control Systems ARDC 26 11
Summary of Non-LWR Design Criteria Discussed during 2017 ACRS Meetings Design Title Applicability Extent of Criteria Modifications Since No. Last ACRS Meeting 10 Reactor Design MHTGR-DC No changes 16 Containment Design ARDC, SFR-DC, MHTGR-DC Minimal changes to SFR-DC 16. No changes to ARDC, or MHTGR-DC 17 Electric Power Systems ARDC (SFR-DC & MHTGR-DC Major changes to design are same as ARDC) criteria and rationale due to ACRS and public comments.
26 Reactivity Control ARDC, SFR-DC, MHTGR-DC Major Changes to both design criteria and rationale due to ACRS and public comments.
12
Summary of Non-LWR Design Criteria Discussed during 2017 ACRS Meetings cont.
Design Title Applicability Extent of Modifications Criteria Since Last ACRS Meeting No.
34 & 35 Residual Heat Removal ARDC 34, SFR-DC 34, No changes to 34. Minor and Emergency Core MHTGR-DC 34, and change to ARDC 35 due Cooling System ARDC 35 to public comments.
70-79 SFR specific criteria SFR-DC 70-79 Minor changes and clarifications to address public comments.
70-72 MHTGR specific criteria MHTGR-DC 70-72 No changes.
13
Interface Between Vision and Strategy Activities 3 and 5 Jan Mazza, Project Manager Advanced Reactor and Policy Branch February 7, 2018
Vision and Strategy for Advanced Reactors Near-Term Implementation Action Plan Strategy 1 Strategy 2 Strategy 3 Strategy 4 Strategy 5 Strategy 6 Knowledge, Computer Flexible Review Industry Codes Technology- Communication Skills and Codes Processes and Standards Inclusive Policy Capacity Issues Identification/ Siting near ORNL Molten Assessment Regulatory ASME BPVC densely NRC DOE Salt Reactor of available Roadmap Sect. III Div. 5 populated Workshops Training tools Areas ANS Knowledge Prototype Standards Insurance and Periodic Management Guidance 20.1, 20.2, Liability Stakeholder 30.2, 54.1 Meetings Non-LWR Consequence Competency Design Non-LWR Based NRC DOE Modeling Criteria PRA Standard Security GAIN MOU Licensing Modernization EP for SMRs International Project: and ONTs Coordination
- LBE Selection
- Defense in Depth Functional
- PRA Approach Containment
- SSC Safety Performance Classification Criteria 15
ACRS COMMENT - Technology Specific Licensing Basis Events Strategy 3, Contributing Activity 3.2, which develops approaches to licensing bases and will determine licensing bases for non-LWR technologies, is particularly important to implement early on. Identification of technology-specific licensing basis events need to be developed to ensure that the associated design criteria are complete.
16
ACRS COMMENT - Facilitate PRA it would be useful to ensure that the language of the ARDCs facilitate, or at least does not preclude, the use of probabilistic risk assessment, especially in the areas where graded compliance is suggested.
17
ACRS COMMENT -
MHTGR Fuel Design Limits MHTGR Design Criterion 10, as presently written, is cryptic. The phrase, specified acceptable system radionuclide release design limit (SARRDL), needs to be clearly defined. Replacing the GDC specific acceptable fuel design limit (SAFDL) concept with the proposed SARRDL concept in the ARDCs is acceptable. However, during design, reactor designers will need to develop their own design-specific limits in order to characterize and evaluate their reactor design. The new SARRDL concept requires additional analysis that the staff will have to review and approve. Later, during operation, licensees will monitor both circulating activity and plate-out activity to ensure acceptable fuel performance, i.e., as evidence that the SARRDLs are being met.
18
Containment -
ARDC 16, SFR-DC 16, and MHTGR-DC 16 Imtiaz Madni, Sr. Reactor Engineer Containment & Ventilation Branch February 7, 2018
ACRS COMMENT - Containment ARDC 16, the functional containment performance requirement, is vague and needs to be defined. For example, the phrases essentially leak tight or low leakage are not adequately defined. An examination for the possibility of reactor pressure boundary failure to induce containment failure should be included explicitly.
20
ARDC 16 Containment Design ARDC Content: Same as GDC 16 NRC Rationale for Adaptations to GDC:
- For non-LWR technologies other than SFRs and MHTGRs, designers may use current GDC to develop applicable principal design criteria.
- However, non-LWR designs could share common features with SFRs and MHTGRs. Hence designers may propose using SFR-DC 16 or MHTGR-DC 16 as appropriate.
- Use of MHTGR-DC 16 will be subject to a policy decision by the Commission.
21
ARDC 16 Containment Design First Part of ACRS Comment: ARDC 16, the functional containment performance requirement, is vague and needs to be defined. For example, the phrases essentially leak tight or low leakage are not adequately defined.
NRC Staff Response:
- The phrase essentially leak tight is used in current GDC 16.
- Appendix J defines the testing requirements for the essentially leak tight barrier.
22
SFR-DC 16 Containment Design SFR-DC Content:
- A reactor containment consisting of a high-strength, low-leakage, pressure-retaining structure surrounding the reactor and its primary cooling system shall be provided to control the release of radioactivity to the environment and to ensure that the reactor containment design conditions important to safety are not exceeded for as long as postulated accident conditions require.
- The containment leakage shall be restricted to be less than that needed to meet the acceptable onsite and offsite dose consequence limits, as specified in 10 CFR 50.34 for postulated accidents.
23
SFR-DC 16 Containment Design cont.
NRC Rationale for Adaptations to GDC:
- The Commission approved the staffs recommendation to restrict the leakage of the containment to be less than that needed to meet the acceptable onsite and offsite dose consequence limits in SECY 93-092, Issues Pertaining to the Advanced (PRISM, MHTGR, and PIUS) and CANDU Designs and their Relationship to Current Regulatory Requirements.
- Therefore, the Commission agreed that the containment leakage for advanced reactors, similar to and including PRISM, should not be required to meet the essentially leak tight statement in GDC
- 16. Reference NUREG-1368, Pre-application Safety Evaluation Report for the PRISM Liquid-Metal Reactor.
24
MHTGR-DC 16 Containment Design MHTGR-DC Content:
- A reactor functional containment, consisting of multiple barriers internal and/or external to the reactor and its cooling system, shall be provided to control the release of radioactivity to the environment and to ensure that the functional containment design conditions important to safety are not exceeded for as long as postulated accident conditions require.
25
MHTGR-DC 16 Containment Design cont.
NRC Rationale for Adaptations to GDC:
- The term functional containment is applicable to non-LWRs without a pressure retaining containment structure.
- A functional containment can be defined as a barrier, or set of barriers taken together, that effectively limit the physical transport and release of radionuclides to the environment across a full range of normal operating conditions, AOOs, and accident conditions.
- The MHTGR functional containment safety design objective is to meet 10 CFR 50.34 ( 52.79) dose requirements at the plants exclusion area boundary (EAB) with margins.
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MHTGR-DC 16 Containment Design cont.
NRC Rationale for Adaptations to GDC:
- The NRC staff has brought the issue of functional containment to the Commission, and the Commission has found it generally acceptable, as indicated in SRM to SECY 93-092 and SECY 03-0047, Policy Issues Related to Non-Light Water Reactor Designs.
- In the SRM to SECY 03-0047, the Commission instructed the staff to develop performance requirements and criteria working closely with industry experts (e.g., designers, EPRI, etc.) and other stakeholders regarding options in this area, taking into account such features as core, fuel, and cooling systems design, and directed the staff to submit options and recommendations to the Commission for a policy decision.
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ACRS COMMENT - Containment Second Part of ACRS Comment An examination for the possibility of reactor pressure boundary failure to induce containment failure should be included explicitly.
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MHTGR-DC 71 Reactor Building Design Basis MHTGR-DC Content:
- The design of reactor building shall be such that, during postulated accidents, it structurally protects geometry for passive removal of residual heat from reactor core to ultimate heat sink and provides a pathway for release of reactor helium from the building in the event of depressurization accidents.
NRC Rationale for Adaptations to GDC:
- The reactor building functions are to protect and maintain passive cooling geometry and to provide a pathway for release of helium from building in case of a line break in reactor helium pressure boundary. This new criterion ensures that these safety functions are provided.
- It is noted that the reactor building is not relied upon to meet the offsite dose requirements of 10 CFR 50.34 (10 CFR 52.79).
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MHTGR-DC 72 Provisions for Periodic Reactor Building Inspection MHTGR-DC Content:
- The reactor building shall be designed to permit (1) appropriate periodic inspection of all important structural areas and the depressurization pathway, and (2) an appropriate surveillance program.
NRC Rationale for Adaptations to GDC:
- This newly established criterion on periodic inspection and surveillance provides assurance that the reactor building will perform its safety functions of protecting and maintaining the configuration needed for passive cooling and providing a discharge pathway for helium depressurization events.
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Electric Power Systems -
ARDC 17 Bob Fitzpatrick, Electrical Engineer Electrical Engineering Branch February 7, 2018
ACRS COMMENT - Electric Power Systems The staff should improve the clarity of ARDC 17 with respect to the term vital functions. Even if electric power is not needed for operational equipment, reliable power is still needed for monitoring plant status, habitability, lighting, and communications.
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Draft Final ARDC 17 (1)
- Electric power systems shall be provided when required to permit functioning of structures, systems, and components. The safety function for each power system shall be to provide sufficient capacity and capability to ensure that (1) that the design limits for the fission product barriers are not exceeded as a result of anticipated operational occurrences and (2) safety functions that rely on electric power are maintained in the event of postulated accidents.
(Bold for discussion purposes) 33
Draft Final ARDC 17 (2)
- The electric power systems shall be comprised of an onsite power system and an additional power system.
The onsite electric power system shall have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure. An additional power system shall have sufficient independence and testability to perform its safety function.
(Bold for discussion purposes) 34
Draft Final ARDC 17 (3)
- If electric power is not needed for anticipated operational occurrences or postulated accidents, the design shall demonstrate that power for important to safety functions is provided.
(Bold for discussion purposes) 35
Draft Final Rationale (1)
- The electric power systems are required to provide reliable power for SSCs during anticipated operational occurrences or postulated accident conditions when those SSCs safety functions require electric power. The safety functions are established by the safety analyses (i.e. design basis accidents).
Where electric power is needed for anticipated operational occurrences or postulated accidents, the electric power systems shall be sufficient in capacity and capability to ensure that safety functions as well as important to safety functions are maintained. The electric power systems provide redundancy and defense-in-depth since there would be a minimum of two power systems.
(Bold for discussion purposes) 36
Draft Final Rationale (2)
- Compared to GDC 17, more emphasis is placed herein on requiring reliability of the overall power supply scheme rather than fully prescribing how such reliability can be attained. For example, reference to offsite electric power systems was deleted to provide for those reactor designs that do not depend on offsite power for the functioning of SSCs important to safety or do not connect to a power grid.
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Draft Final Rationale (3)
- The onsite power system is envisioned as a fully Class 1E power system and the additional power system is left to the discretion of the designer as long as it meets the performance criteria in paragraph one and the design criteria of paragraph two. For example, the additional independent power source could be from the electrical grid, a diesel generator, a combustion gas turbine or some other alternative, again, at the discretion of the designer.
(Bold for discussion purposes) 38
Draft Final Rationale (4)
- Important to safety functions include post-accident monitoring, control room habitability, emergency lighting, radiation monitoring, communications and/or any others that may be deemed appropriate for the given design. The electric power system for important to safety functions could be non-Class 1E and would not be required to have redundant power sources.
(Bold for discussion purposes) 39
Conclusion The staff has added specificity to ARDC-17 (SFR-17 and MHTGR-17) in response to prior suggestions by the ACRS.
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Reactivity Control Systems -
ARDC 26 Jeff Schmidt, Sr. Reactor Engineer Reactor Systems Branch February 7, 2018
ACRS COMMENT - Reactivity Control Systems ARDC 26 eliminated the GDC 26 requirement for controlling the rate of reactivity changes resulting from planned, normal power changes.
For harder spectrum reactors, particularly for liquid fuel systems, control of the rate of reactivity insertion can be very important and should be retained.
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ARDC 26
- As previously discussed, GDCs 26 and 27 have been combined into ARDC 26 and deal with reactivity control under AOO and postulated accidents.
- In part, ARDC 26 was rewritten as the term reliably controlling reactivity changes in GDCs 26 and GDC 27 was ambiguous.
- Revised ARDC 26 provides explicit performance criteria on rate and amount of negative reactivity insertion.
- ARDC 26 was significantly revised based on ACRS and public comments of the draft guide.
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Draft Final ARDC 26 A minimum of two reactivity control systems or means shall provide:
- 1) A means of inserting negative reactivity at a sufficient rate and amount to assure, with appropriate margin for malfunctions, that the design limits for the fission product barriers are not exceeded and safe shutdown is achieved and maintained during normal operation, including anticipated operational occurrences.
- 2) A means which is independent and diverse from the other(s), shall be capable of controlling the rate of reactivity changes resulting from planned, normal power changes to assure that the design limits for the fission product barriers are not exceeded.
- 3) A means of shutting down the reactor and maintaining, at a minimum, a safe shutdown following a postulated accident, with appropriate margin for malfunctions, shall be provided.
- 4) A means for holding the reactor shutdown under conditions which allow for interventions such as fuel loading, inspection and repair shall be provided.
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ARDC 26 AOO Mitigation Criteria
- 1. A means of inserting negative reactivity at a sufficient rate and amount to assure, with appropriate margin for malfunctions, that the design limits for the fission product barriers are not exceeded and safe shutdown is achieved and maintained during normal operation, including anticipated operational occurrences.
- Modified to address comments that draft guide ARDC 26 only focused on shutdown and did not address the rate of reactivity insertion
- Establishes the performance criteria that safe shutdown is achieved and maintained during and following an AOO
- 2. A means which is independent and diverse from the other(s), shall be capable of controlling the rate of reactivity changes resulting from planned, normal power changes to assure that the design limits for the fission product barriers are not exceeded.
- Added to address ACRS concern about controlling reactivity changes during normal plant operation which is independent and diverse from the means in ARDC 26 criterion (1)
- The purpose is to provide additional protection of the fission product barriers and limit challenges to protective actions 45
ARDC 26 Postulated Accident Criteria
- 3) A means of shutting down the reactor and maintaining, at a minimum, a safe shutdown condition following a postulated accident, with appropriate margin for malfunctions, shall be provided.
- The word following was included to establish that the shutdown should be achieved in the long term, equilibrium state
- Allows re-criticality in the short term consistent with some licensed PWR postulated accidents if sufficient heat removal capability exists 46
ARDC 26 Cold Shutdown
- 4) A means for holding the reactor shutdown under conditions which allow for interventions such as fuel loading, inspection and repair shall be provided.
- ARDC criterion 4 replaces the last sentence in GDC 26 which states, one of the systems shall be capable of holding the reactor core subcritical under cold conditions.
- Received public comments that cold implies below 212 oF and is very design dependent (e.g., SFR)
- SECY 94-084 and Regulatory Guide 1.xx state the desire to achieve cold shutdown is driven by inspection and testing concerns, therefore the criterion 4) was modified to eliminate the word cold and reflect the primary performance criteria 47
Public Comment Summary
- NRC received 127 comments from 10 stakeholders
- Of the 127 comments, staff agreed with 64 of them and made the appropriate changes to the RG.
- The most significant comments were in the areas discussed today and during the August 24 and November 2 public meetings.
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Next Steps
- NRC Staff believes that we have addressed all of the public comments satisfactorily.
- Looking forward to ACRS feedback.
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Acronyms ACRS Advisory Committee for Reactor Safeguards ARDC Advanced Reactor Design Criteria AOO Anticipated Operational Occurrence CFR Code of Federal Regulations DiD Defense in Depth DOE U.S. Department of Energy DC Design Criteria EPRI Electric Power Research Institute EP Emergency Planning EAB Exclusion Area Boundary GDC General Design Criteria LBE Licensing Basis Event LWR Light Water Reactor MHTGR Modular High Temperature Gas Reactor ONT Other Nuclear Technologies PDC Principal Design Criteria PRA Probabilistic Risk Assessment PRISM Power Reactor Innovative Small Modular RG Regulatory Guide SMR Small Modular Reactor SFR Sodium-Cooled Fast Reactor SAFDL Specified Acceptable Fuel Design Limit SARRDL Specified Acceptable System Radionuclide Release Design Limit SRM Staff Requirements Memorandum SSC Structures, Systems, and Components 50
Back-Up Slides 51
MHTGR-DC 70 Reactor Vessel and Reactor System Structural Design Basis mHTGR-DC Content:
- The design of the reactor vessel and reactor system shall be such that their integrity is maintained during postulated accidents (1) to ensure the geometry for passive removal of residual heat from the reactor core to the ultimate heat sink and (2) to permit sufficient insertion of the neutron absorbers to provide for reactor shutdown.
NRC Rationale for Adaptations to GDC:
- New MHTGR design-specific GDC are necessary to ensure that the reactor vessel and reactor system (including the fuel, reflector, control rods, core barrel, and structural supports) integrity is preserved for passive heat removal and for the insertion of neutron absorbers.
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Revised ARDC 26 Postulated Accident Criteria
- 3) A means of inserting negative reactivity at a sufficient rate and amount to assure, with appropriate margin for malfunctions, that the capability to cool the core is maintained and a means of shutting down the reactor and maintaining, at a minimum, a safe shutdown condition following a postulated accident 53