ML23352A309
| ML23352A309 | |
| Person / Time | |
|---|---|
| Issue date: | 11/17/2023 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| NRC-2629 | |
| Download: ML23352A309 (1) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Radiation Protection Subcommittee Docket Number: (n/a)
Location: teleconference Date: Friday, November 17, 2023 Work Order No.: NRC-2629 Pages 1-160 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1716 14th Street, N.W.
Washington, D.C. 20009 (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.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com
1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 + + + + +
4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5 (ACRS) 6 + + + + +
7 RADIATION PROTECTION SUBCOMMITTEE 8 + + + + +
9 FRIDAY, NOVEMBER 17, 2023 10 + + + + +
11 The Subcommittee met in a Hybrid Meeting, 12 In-Person and via Video-Teleconference, at 8:30 a.m.
13 EST, Ron Ballinger, Chairman, presiding.
14 SUBCOMMITTEE MEMBERS:
15 JOY L. REMPE, Chairman 16 WALTER L. KIRCHNER, Vice Chairman 17 DAVID A. PETTI, Member-at-Large 18 RONALD G. BALLINGER, Member 19 VICKI M. BIER, Member 20 CHARLES H. BROWN, JR. Member 21 GREGORY H. HALNON, Member 22 JOSE MARCH-LEUBA, Member 23 ROBERT P. MARTIN, Member 24 THOMAS E. ROBERTS, Member 25 MATTHEW W. SUNSERI, Member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
2 1 ACRS CONSULTANT:
2 DENNIS BLEY 3 STEVE SCHULTZ 4 DESIGNATED FEDERAL OFFICIAL:
5 CHRISTOPHER BROWN 6 ALSO PRESENT:
7 HAROLD ADKINS, PNNL 8 GARILL COLES, PNNL 9 JEFF ENGLAND, NAC International 10 DANIEL FORSYTH, NRC 11 SHANA HELTON, NRC 12 STEVE MAHERAS, PNNL 13 JONATHAN MARCANO, NRC 14 TIM McCARTIN, NRC 15 VIRGIL PEOPLES, INL 16 STEVE SHORT, PNNL 17 BRIAN WAGNER, NRC 18 JEFF WAKSMAN, SCO 19 BERNARD WHITE, NRC 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
3 1 AGENDA 2 PAGE 3 Opening Remarks and Objectives . . . . . . . . . 4 4 Staff Opening Remarks . . . . . . . . . . . . . 7 5 SCO Opening Remarks . . . . . . . . . . . . . . 12 6 PNNL Presentation . . . . . . . . . . . . . . . 17 7 NRC Presentation . . . . . . . . . . . . . . . 114 8 Public Comments . . . . . . . . . . . . . . . . 149 9 Discussion . . . . . . . . . . . . . . . . . . 150 10 Adjourn 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
4 1 P-R-O-C-E-E-D-I-N-G-S 2 8:30 a.m.
3 CHAIRMAN BALLINGER: The meeting will now 4 come to order. This is a meeting of the Radiation 5 Protection Subcommittee of the Advisory Committee on 6 Reactor Safeguards. I'm Ron Ballinger, chairman of 7 today's subcommittee meeting.
8 ACRS members in attendance are Charlie 9 Brown, Greg Halnon, Bob Martin, Vicki Bier, Joy Rempe, 10 Dave Petti, Tom Roberts. Let's see -- a line. I'm 11 guessing that Matt Sunseri will be here, Jose March --
12 MEMBER SUNSERI: Yes, I'm on.
13 CHAIRMAN BALLINGER: Good, thank you.
14 Jose March-Leuba and --
15 MEMBER MARCH-LEUBA: Yes, I'm here.
16 CHAIRMAN BALLINGER: Great. We have our 17 consultant, Steve Schultz, and I believe Dennis Bley, 18 am I right?
19 MEMBER KIRCHNER: And Ron, this is Walt.
20 I'm here as well.
21 CHAIRMAN BALLINGER: Oh, wonderful, and 22 Walt Kirchner. Thank you. Vesna is sick this 23 morning, so she won't -- yeah. Okay, Chris Brown is 24 the designated federal official for the meeting. He's 25 around here somewhere.
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5 1 During today's meeting, the subcommittee 2 will receive a briefing on risk-informed methodology 3 for a transportable micro-reactor package. The 4 subcommittee will hear presentations by and hold 5 discussions with the NRC staff, PNNL and its 6 contractors, and other interested persons regarding 7 this matter.
8 Let's say a little bit more about this.
9 This meeting is for an information meeting only unless 10 we decide to write a letter, which is not up to me.
11 Also, personally, I believe that if you were to take 12 the word Pele out of this document, the PNNL document, 13 and substitute any other micro-reactor, or spent 14 nuclear fuel for that matter, this document or this 15 methodology would be equally appropriate, and so I 16 think what we're going to hear about today is a 17 methodology which is a much broader application than 18 for Pele.
19 The rules for participation in all ACRS 20 meetings were announced in the Federal Register on 21 June 13, 2019. The U.S. NRC public website provides 22 the ACRS charter, bylaws, agendas, letter reports, and 23 full transcripts of all full and subcommittee 24 meetings, including slides.
25 The ACRS only speaks through its published NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
6 1 letter reports. The agenda for this meeting was 2 posted on the NRC website along with an MS Teams link.
3 We have received no written statements or requests to 4 make an oral statement from the public.
5 Today, the subcommittee will gather 6 information, analyze relevant issues and facts, and 7 formulate proposed positions and actions, as 8 appropriate. A transcript of the meeting is being 9 kept and will be made available.
10 Today's meeting is being held over 11 Microsoft Teams, as I mentioned. There is also a 12 telephone bridge line, as well as a link allowing 13 participation of the public.
14 When addressing the subcommittee, the 15 participants should first identify themselves and 16 speak with sufficient clarity and volume so that they 17 may be readily heard. When not speaking, we request 18 that participants mute your computer microphone or 19 phone by pressing star-6. Otherwise, we'll get 20 feedback in here, which will be disruptive. We remind 21 participants not to use the chat feature to answer 22 questions or make comments.
23 Before we start, three members have been 24 identified as having conflict of interest. Members 25 Petti, Sunseri, and Martin have been identified as NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
7 1 having a conflict of interest, so they can be here, 2 but not participate in the deliberation. We'll now 3 proceed with the meeting and start by --
4 MEMBER SUNSERI: Hey, Ron. This is Matt.
5 I have not declared a conflict of interest. I don't 6 have one.
7 CHAIRMAN BALLINGER: Sorry, no, okay, 8 cross that off, great, okay. That's my second mistake 9 so far today. There will be many. Okay, we'll now 10 proceed with the meeting and start by calling on Shana 11 Helton, director of the Division of Fuel Management, 12 NMSS, for opening remarks. Shana?
13 MS. HELTON: Thank you very much, and I 14 really appreciate the opportunity for you to hear from 15 our staff today.
16 CHAIRMAN BALLINGER: Shana, you've got to 17 almost swallow the mic.
18 MS. HELTON: Do I have to like -- okay, 19 sorry. Is this better, sound better?
20 CHAIRMAN BALLINGER: Yeah.
21 MS. HELTON: Okay, great. Thank you.
22 Thanks for the opportunity to be here today. I'm 23 really excited for you to hear from our staff who have 24 been working so hard on this Project Pele. This has 25 been a really high priority for NMSS and for our NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
8 1 division as we continue to fulfill our regulatory 2 role, and as we support the nation's development of 3 this advanced technology.
4 Bernie will discuss the details of the 5 NRC's role in this project, and before I turn it over 6 to him and others at the table, I'd like to recognize 7 the NRC staff who have also been performing the review 8 and assisting in drafting and editing the endorsement 9 letter and method evaluation, including Brian Wagner, 10 Tim McCartin, Juan Lopez, Loren Howe, Chris Bajwa, Dan 11 Forsyth, Drew Barton, Jeremy Tapp, and others from --
12 those are all in the Division of Fuel Management.
13 We have other staff in the agency, Matt 14 Humberstone from the Office of Nuclear Regulatory 15 Research, Steve Philpott, Jorge Hernandez Munoz, Duke 16 Kennedy, and Amy Cubbage from the Office of Nuclear 17 Reactor Regulation, and Matt Sumerov (phonetic) from 18 the U.S. Department of Transportation, who is a 19 partner with us in all matters regarding 20 transportation of radioactive materials.
21 So, while you're hearing from a few today, 22 as well as folks from the lab who were very involved 23 with this effort, there is a lot of effort behind the 24 scenes supporting the presentations that you'll hear 25 about today, and I thank everybody who has been NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
9 1 involved with us to date.
2 So, as Dr. Ballinger noted, ACRS views are 3 very welcome to the staff. It will inform the work 4 that we're doing, and we're looking forward to a very 5 productive discussion. Unless the Committee chooses, 6 we're not looking for a letter at this time, but of 7 course, that's not my decision to make.
8 As Dr. Ballinger noted, that would be a 9 decision by the Committee. So, but, you know, for 10 now, we're looking forward to a good information 11 presentation, and I'll turn it over to the next 12 speaker. Thank you.
13 MEMBER REMPE: So --
14 CHAIRMAN BALLINGER: Jeff are you going to 15 --
16 MEMBER REMPE: Before you start, I guess 17 I have a question. I mean, you have the safety 18 evaluation and you said well, we'll be informed by 19 what ACRS says today. Would some of the questions we 20 raise maybe, would they be used in an update to your 21 safety evaluation or is it, is the water -- has the 22 ship already sailed and it's too late?
23 MS. HELTON: No, it's not too late. We 24 are still continuing to work on the safety evaluation.
25 The one that we made public to support this meeting is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
10 1 a draft and that was really just to ensure that we 2 have a good, full public discussion.
3 The draft that the ACRS has, has not yet 4 been fully reviewed by management. I think there's a 5 big disclaimer on there that our lawyers helped us 6 write. So, we're continuing to finalize our review, 7 and Bernie will get into the schedule and the next 8 steps for the remainder of our efforts.
9 MEMBER REMPE: Yeah, we can find out if 10 there happens to be some divine insights from the 11 members that would be recognized and addressed, and 12 maybe we could have a short meeting at full Committee 13 to say yeah, we agreed and did something.
14 MS. HELTON: Absolutely.
15 MEMBER REMPE: Thank you.
16 CHAIRMAN BALLINGER: Let me get a little 17 bit of clarity here. What the staff did was to review 18 the document. I don't believe this document that we 19 got is called the safety analysis, so it's not a 20 safety analysis.
21 MEMBER REMPE: Well, no, a safety 22 evaluation, but --
23 CHAIRMAN BALLINGER: It's not a safety --
24 it's a review.
25 MEMBER REMPE: It's an evaluation is --
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11 1 CHAIRMAN BALLINGER: So --
2 MEMBER REMPE: -- what I've heard, right?
3 CHAIRMAN BALLINGER: So, that makes it a 4 little bit different than the normal procedure that we 5 have.
6 MS. HELTON: Right, we're not actually 7 reviewing a transportation package design. We don't 8 have the safety analysis in front of us to review.
9 What we're going to present on today is our thoughts 10 on the risk method and it is a little bit different.
11 As you know, it's sort of akin to -- I think of it 12 like a topical report sort of review, although we're 13 not calling it that, but it's that sort of process 14 where we're looking at the method.
15 And Bernie will talk about how the next 16 step, you know, assuming that the NRC makes a 17 favorable finding, of the method would be for an 18 applicant for a transportation package design to use 19 that method and apply it to their package and use it 20 to demonstrate how they meet the requirements of 10 21 CFR Part 71, so I hope that helps.
22 CHAIRMAN BALLINGER: So, to add a little 23 bit more clarity, so what you're inferring is that at 24 a later time, there may be a document which we do 25 formally review and you would require, would like a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
12 1 letter?
2 MS. HELTON: Yes, we'll be presenting 3 about that today.
4 CHAIRMAN BALLINGER: Okay.
5 MEMBER REMPE: But once this evaluation, 6 isn't that what it's called is an evaluation, is 7 completed, would it be considered an approved 8 approach? So, if we have a concern, we ought to make 9 sure we get it down now instead of after somebody 10 comes in that's an applicant and says well, we had the 11 evaluation. It was approved or received a favorable 12 outcome from the NRC. So, it's better to make sure 13 that if we have a concern, to raise it now instead of 14 later, right?
15 MS. HELTON: Yeah, I think we're open to 16 any thoughts that you have today.
17 CHAIRMAN BALLINGER: Okay, Jeff, do you 18 want to make a comment?
19 MR. WAKSMAN: Sure, so I definitely want 20 to thank everyone for coming here today and I want to 21 echo what Dr. Ballinger said up front about this being 22 a lot broader than Pele. In fact, this is intended to 23 be much broader than Pele.
24 The Pele reactor, as we have plans now, is 25 not going to leave the Idaho National Laboratory site NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
13 1 after it's been operated. The intention is to test 2 the transportability just by driving it around the 3 property.
4 But the purpose of Project Pele is not to 5 just do a prototype. It's to have follow-ons, and so 6 we are hoping that the DoD will purchase more 7 reactors, which will probably be a different design, 8 so we want this to be much broader than just the Pele 9 design and its specifics.
10 And so, I think so far, we've had a really 11 good dialogue and working relationship with the NRC 12 team, with Bernie and all of his folks, and so with 13 that, I'm going to turn it over to the person who 14 understands this a lot better than me, Harold.
15 MR. BLEY: Ron, this is Dennis.
16 CHAIRMAN BALLINGER: Yeah?
17 MR. BLEY: Dennis Bley. From the staff, 18 I'm a little interested in exactly how you see what 19 you're doing now. To my knowledge, NMSS and NRC, with 20 regards to transportation in the past, has regulated 21 the integrity of transportation casks for spent fuel.
22 This, I believe, is the first time you've 23 looked at transportation of an actual reactor, either 24 before it's been operated or after it's been operated, 25 and is that going to require a new rule or where do NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
14 1 you see this going?
2 MR. WHITE: So, this is Bernie White, NRC 3 staff. So, if you look at the transportation 4 regulations in Part 71, they're fairly broad. They 5 cover a wide variety of packages, and essentially none 6 are specified by name. So, we have Type B packages 7 and we have fissile material packages.
8 If we were to approve a transportable 9 micro-reactor prior to shipment, it would likely be a 10 Type A fissile package, which is different from a Type 11 A package. After irradiation or after use, it would 12 likely be a Type B fissile package and it would have 13 to meet the requirements for a Type B fissile package 14 or use an alternative approval pathway that I had 15 mentioned previously in the October 3 ACRS meeting, 16 which would include alternative testing conditions or 17 exemptions.
18 The proposal here from PNNL is a, and from 19 SCO is, I like to think of it as a roadmap. It's how 20 to get from point A to point B, but you never know 21 along the way when there's going to be a road closed 22 or a detour and you've got to do something different, 23 and so that's kind of how we see it. It's a method to 24 get us to be able to develop an application for 25 package approval for the Pele micro-reactor.
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15 1 MR. BLEY: Okay, thanks, and I guess that 2 means you think the regulations that exist for Type As 3 and Type B packages are going to be able to cover 4 this? We don't need new regulation?
5 MR. WHITE: This is Bernie White again, 6 NRC staff. At this point, yes, and you know, part of 7 the reason for that is in the conversations we've had 8 with micro-reactor developers, so far none other than 9 the Pele development of this methodology have 10 indicated they need to use exemptions.
11 You know, staff is always balancing the 12 act between what staff can do on its own and what is 13 a policy issue for the Commission. You know, if we 14 were to hear of eight or ten micro-reactor developers 15 that need to use exemptions, you know, it might be 16 best to not regulate the exemption. It might be best 17 to do rulemaking. We're still evaluating that at this 18 point.
19 MR. BLEY: Thanks very much.
20 MS. HELTON: Bernie, this is Shana Helton 21 again. If I could just add, so, you know, these are 22 all exactly the types of questions that we hope to 23 answer today with the staff presentation.
24 Following, you know, Dr. Waksman from SCO 25 will be talking, along with PNNL, about the risk NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
16 1 methodology itself, and then our intent with the staff 2 presentation is to get into the details of how we're 3 looking at the method, how we see that fitting into 4 our framework for this one time, for Project Pele, and 5 then some of our considerations and next steps going 6 forward. So, I do believe we'll have the chance later 7 today to really get into these considerations.
8 Part 71, I just wanted to note, and Bernie 9 will probably talk about this during his presentation, 10 has been used for some different types of shipments 11 that don't look like what you think about with your 12 typical radioactive material spent fuel types of 13 transportation.
14 We've done some sort of -- and there's 15 provisions in the regulations that allow for the use 16 of alternate criteria, and of course, exemptions are 17 always a possibility for a one-time, unique situation.
18 So, Bernie will get into all of that and the 19 flexibilities that are in the Part 71 as it's written 20 today. Thanks.
21 CHAIRMAN BALLINGER: Okay, we may be 22 getting ahead of ourselves, but in the document 23 itself, there's a statement. Given these observations 24 and the fact that this is a first-of-a-kind endeavor, 25 it is recommended, however, that a PRA standard for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
17 1 TNPP transportation would greatly aid the NRC approval 2 process, so that's from your document itself. Okay, 3 who is the presenter?
4 MR. ADKINS: It's Harold Adkins --
5 CHAIRMAN BALLINGER: Ah, okay.
6 MR. ADKINS: -- from PNNL. First of all, 7 I'd like to thank the Advisory Committee on Reactor 8 Safeguards, the Nuclear Regulatory Commission --
9 CHAIRMAN BALLINGER: Can you get a little 10 closer to the --
11 MR. ADKINS: Oh, you bet. Sorry about 12 that. I figured I was loud enough.
13 CHAIRMAN BALLINGER: Or just pull the 14 thing -- there you go.
15 MR. ADKINS: How's that? Terrific.
16 Anyway, so Garill Coles and myself will be primarily 17 providing the presentation, but I brought some support 18 staff that range all the way from Army transport 19 logistics experts to thermal hydraulic structural 20 reactor physics experience and things of that nature, 21 risk and decision making, and also consequence.
22 Anyway, so thank you for allowing us to 23 present on the development and application of a risk-24 informed approach for highway shipment of a micro-25 reactor. Next slide, please?
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18 1 The very first thing that we want to do, 2 our objective here is to propose background 3 information on a proposed risk-informed regulatory 4 approach to the transportation of a transportable 5 nuclear power plant, and we use that loosely because 6 one of the things that we'll get into is, the one 7 example that we make is where the reactor module is 8 separated from the balance of the plant and sealed off 9 and prepped for transport as a transportation package, 10 and all of this is being developed in support of an 11 NRC draft safety evaluation or a SAR submittal from 12 the applicant.
13 We'll provide a brief description of the 14 TNPP, the one we made an example of, which is Project 15 Pele. We'll provide a description of the proposed 16 risk-informed regulatory pathway that we're proposing 17 for the TNPP transport.
18 We'll go through some development of risk 19 evaluation guidelines, some description of 20 quantitative risk assessment process using integrated 21 assessment processes based on probabilistic risk 22 assessment. That's the coupling to that, some 23 methods, which include consideration of defense-in-24 depth, and also consideration of safety margin.
25 We'll also make some examples of results NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
19 1 of applying the proposed PRA and risk evaluation 2 guidelines to the TNPP, for an example, a description 3 of the approach to the results of the sensitivity 4 studies and then certain analyses that we performed 5 only as an example of pathway and process, because 6 that would still be the burden of the applicant, and 7 then provide some insights gained for implementing and 8 demonstrating our proposed approach. Next slide, 9 please?
10 So, first out of the gate, we talked about 11 what a TNPP is. Many advanced reactor vendors are now 12 proposing and developing TNPPs to make higher density 13 energy readily available for -- specifically, one of 14 the major drivers and funders of this activity was 15 DoD's Strategic Capabilities Office.
16 Jeff Waksman provided us the capability of 17 developing this on behalf of SCO, and it's for the 18 Department of Defense domestic infrastructure 19 resilience to electric grid attack.
20 It's also being developed to enable rapid 21 response for humanitarian aid and disaster relief 22 operations, to be able to expedite that, again with 23 high-energy density, and then also to provide clean 24 carbon energy in a variety of austere conditions or 25 off-grid locations.
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20 1 The one convention that I do want to make 2 clear here is the TNPP convention would be a factory-3 produced, fueled, acceptance tested, deployed and 4 sealed units that are prepared for transport as a 5 transportation package. They would be utilized and 6 then retrieved for refueling or reapplication, meaning 7 that our main focus and the critical portion of this 8 would be the post-transport shipment, meaning the 9 spent fuel is within it, and the considerations 10 associated with that. Next slide, please.
11 To make an example, again of Project Pele, 12 that we used to do the development. It's a one to 13 five megawatt electric minimum of three years' 14 operating time for full power. Obviously, the 15 lifetime would be longer than that if it was utilized 16 at anything other than full power. It's a high-17 temperature gas reactor using high-assay, low-enriched 18 uranium, uranium oxycarbide tristructural isotropic 19 fuel.
20 In the Pele convention, it's separated 21 into four modules, one of which is the reactor module 22 or heat generation module, then you have an 23 intermediate heat exchanger module, a control module, 24 and a power conversion module. However, a bulk 25 majority of the radionuclide inventory would reside in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
21 1 the heat generation module, the reactor module, and 2 the balance is anticipated in the intermediate heat 3 exchanged module.
4 Each one of these modules in the Pele 5 convention is housed within a CONEX box to look like 6 simple cargo, and a CONEX box is like a shipping 7 container that you would see on a shipping port or on 8 a cargo ship, and then the image to the right 9 basically that you see is a caricature or a rendering 10 of a deployment for Army application. Next slide, 11 please?
12 So, U.S. transportation regulatory 13 requirements contained in 10 CFR 71, yeah, 10 CFR 71, 14 sorry, primarily focus on the definition of thick-wall 15 pressure vessels that are intended for spent nuclear 16 fuel transport. A TNPP with irradiated fuel, like we 17 talked about the convention that we're discussing and 18 focusing on, prepared as a package for transport could 19 be challenged to meet the entire suite of codified 20 regulatory performance requirements in 10 CFR 71.
21 The one thing I want to be clear on though 22 is it's fully anticipated that TNPP would be able to 23 meet or at least be deterministically shown to meet 24 normal conditions of transport because that would be 25 like a general commerce state where you can't have any NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
22 1 particular incidents or you want to mitigate those 2 incidents.
3 However, it may be a bit challenging to 4 demonstrate that the level of robustness of current 5 proposed TNPP technology can fully meet these 6 requirements, such as dose rate requirements and 7 containment success criteria when exposed to a 8 postulated hypothetical accident condition that's 9 charted out in 10 CFR 71.73, and what I mean by that 10 is the sequential 30-foot drop. It's the worst case 11 scenario, a crush, puncture-free drop, a 30-minute 12 engulfing hydrocarbon fire, and then water immersion 13 tests.
14 One of the things that we're focusing on 15 too is leveraging compensatory measures and defense-16 in-depth approaches along with philosophies to 17 reestablish the equivalent safety that would be 18 provided by the codified regulatory requirements.
19 We're also absolutely intending on leveraging 20 consideration of the TRISO compact fuel sleeve core, 21 all of these retention and protection boundaries to 22 provide equivalent safety. Next slide, please?
23 If a fissile material or Type B package 24 like we discussed previously can't meet the postulated 25 hypothetical accident requirements in 10 CFR 71.73, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
23 1 there's a couple of options that the NRC considers.
2 First of all, there's a 10 CFR 71.41(c), which it's 3 detailed in that, as an alternative environmental and 4 test condition state.
5 This has been applied to two separate 6 packages in the past, ones I'm just making example of, 7 which is the 10-160B and the 8-120B. In those 8 particular cases, the one workaround that had to be 9 navigated was the low temperature transport 10 application, so they took an exception to the 11 transporting at the lowest possible temperature.
12 The next one is this special packaging 13 authorization that's been applied to the West Valley 14 Melter Package, and that one's slated out in 10 CFR 15 71.41(d). That only allows for a single-time 16 shipment, so from source to destination, and then that 17 SPA is expired.
18 The one consideration that we're taking 19 into account probably that would be the most fruitful 20 is the 10 CFR 71.12 exemption that's been applied to 21 the Trojan Reactor Vessel, and in that particular 22 case, the reactor vessel was transported up the 23 Columbia River to the Hanford Site, and then 24 transported to its destination, and compensatory 25 actions were taken into account because it was too NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
24 1 large to actually perform the physical testing or 2 taking a look at that.
3 Our preferred approach initial pathway 4 that we identified was the exemption process, again, 5 that allows compensatory actions to protect the basis 6 for the exemption if acceptable risk is demonstrated.
7 We can apply it to more than one shipment, first of 8 all.
9 That's one of the major drivers, and then 10 the other thing is there's flexibility in deviated 11 from the deterministic requirements, especially HAC 12 requirements, to alternative environment and test 13 conditions like I talked about where only one 14 particular item is a weakness like the low-temperature 15 application. Next slide.
16 MEMBER HALNON: Harold, this is Greg.
17 Just a real quick question.
18 MR. ADKINS: Yeah.
19 MEMBER HALNON: Is your approach very 20 specific to the Pele reactor or are you broadening it 21 out to include potentially bounding some other types?
22 What about TRISO fuel and other things?
23 MR. ADKINS: Excellent question. For the 24 time being, it's not fixated on Pele, but the one 25 requirement that we've all agreed, without during NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
25 1 further work, it will likely be tied to TRISO fuel.
2 MEMBER HALNON: Okay, so it's TRISO fuels 3 centric rather than --
4 MR. ADKINS: Exactly, exactly.
5 MEMBER HALNON: Thanks.
6 MR. ADKINS: That doesn't mitigate us 7 from, you know, moving further and considering other 8 things that might be tied to an alternative reactor 9 design.
10 MEMBER HALNON: Okay, because I know that 11 there's some molten salt reactors out there that --
12 MR. ADKINS: Right.
13 MEMBER HALNON: -- are looking at a 14 similar aspect, only different fuel.
15 MR. ADKINS: Okay, or sodium-cooled.
16 Thank you. Good question. Thank you. Thank you.
17 So, quantitative risk analysis approaches such as PRA 18 have been applied and used in risk-informed regulatory 19 pathways for licensing particular systems, especially 20 in reactors, since the 1970s nuclear reactors.
21 PRA has been applied ever since WASH-1400 22 and used since the 2000s for licensing. PRA has also 23 been applied to dry cask storage systems, as well as 24 transportation systems, and I've identified a couple 25 of NUREGs that highlight a lot of that.
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26 1 One of the reasons that we're focusing on 2 this and proposing to the NRC is to provide an aid for 3 developing the near-term pathway to drive advanced, 4 factory-produced TNPP development and deployment. The 5 other thing too is, you know, going back to the 6 comment that I made about the codified regulatory 7 requirements almost exclusively revolving around 8 thick-wall pressure vessels.
9 When you take into consideration like a 10 spent fuel cask, and then also as the TNPPs go through 11 a refinement process and robustness where those two 12 points come together in, you know, consideration of 13 regs and things of that nature, it provides buffer 14 time for strategic regulatory consideration and the 15 possibility of rulemaking to more so accommodate 16 advanced, transportable, and micro-reactor 17 conventions. I'm going to hand the rest of the 18 presentation over to my colleague, Garill Coles, to 19 speak to the risk-centric items.
20 MR. COLES: Okay, Harold, I'll take it 21 from slide eight. Yeah, so we contend that a 22 demonstration of acceptable risk, if the exemption 23 process is used, would require a quantitative risk 24 assessment given possible complexities and 25 uncertainties about the package performance and the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
27 1 potential risk to the public, and in fact, that this 2 would be a first-of-a-kind endeavor.
3 Moreover, unlike the Trojan Reactor Vessel 4 example, it is unlikely that all accident scenarios 5 would be screened based on likelihood. PRA provides 6 a rigorous quantitative approach.
7 And concerning risk evaluation guidelines, 8 assessment using PRA worked best and was supported by 9 guidelines about acceptable use, acceptable risk, 10 because they provide a key basis for risk-informed 11 decision making. However, regulatory risk evaluation 12 guidelines using PRA do not exist for transportation 13 packages like they do for nuclear power plants.
14 That said, risk-informed decision making 15 guidance using PRA and other risk assessment 16 approaches is proposed for nuclear material and waste 17 applications in the 2008 NRC report titled Risk-18 Informed Decision Making for Nuclear Material and 19 Waste Applications Rev. 1, and we're going to refer to 20 this report, and there are times in this presentation 21 I'll shorthand it by calling it the 2008 RIDM report.
22 The guidance in that report includes 23 proposed quantitative health guidelines developed from 24 the 1986 NRC Safety Policy Statement. However, 25 challenges remain in implementing the guidance, and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
28 1 the approach has not been endorsed for use by NRC for 2 transportation. So, this slide --
3 MEMBER ROBERTS: Garill?
4 MR. COLES: Yes?
5 MEMBER ROBERTS: This is Tom Roberts. I 6 have one question about the 2008 RIDM report. It 7 might be a question for staff, but I'm going to ask 8 you first. It doesn't talk about the qualitative 9 safety goals from the 1986 statement.
10 One of the qualitative goals addresses 11 societal risk and, you know, a wise person once 12 explained to me that one of the biggest differences 13 between transportation and other regulations is 14 because transportation can go through population areas 15 without any real controls over population.
16 That's distinct from a nuclear reactor 17 plant that has guidelines like population density 18 guidelines and, you know, LPZs and maybe EABs and that 19 type of thing, which don't apply here. So, this is 20 kind of a battery condition for reactor risk analyses 21 that don't apply to transportation.
22 So, I was wondering what your thoughts 23 were on societal risk, whether you thought about the 24 need for a societal risk goal in your quantitative 25 assessments, and if not, how that's considered in kind NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
29 1 of the overall overhead with the analysis you're 2 doing?
3 MR. COLES: Well, as you say, right, there 4 are no guidance using PRA. There's no -- and we 5 didn't try to rethink. That's almost like rulemaking 6 or something. So, we used -- and I'll explain this in 7 the next slides, right?
8 I basically used the information at hand, 9 and most of the information at hand is for facilities, 10 as you say, and that is different, and we'll explain 11 how it's different and what we did about that.
12 MEMBER ROBERTS: Okay, yeah, I'll be 13 interested in hearing that. I noticed the 14 transportation risk analysis that you cited had an 15 awful lot of tables of person-rem, and so they were 16 looking not at just the individual risk, but the total 17 population risk, though I didn't really see a 18 conclusion that was drawn, so that's probably 19 consistent with the Commission not establishing a 20 quantitative goal back 1986 because it's --
21 MR. COLES: Right.
22 MEMBER ROBERTS: -- not obvious what that 23 goal would be, but certainly there was consideration 24 of overall populations in that report. And the 25 guidance, yeah, in your report are these guidelines on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
30 1 the slide you're about to present, so I just wanted to 2 get your perspective on -- and maybe this is a 3 question for Bernie when his turn comes up, but if 4 staff thought about that in terms of how you would 5 look at the societal risk considering when you're 6 looking at a risk analysis that's focused on the risk 7 to the individual.
8 MR. COLES: Yeah, bring up the question 9 again if we don't answer. So, this slide does show 10 the quantitative health guidelines proposed in the 11 RIDM report. Of course, the premise of the safety 12 goal policy is that risks to people from nuclear power 13 plants should be very small compared to the sum of 14 other accident risks. That's the one-tenth of one 15 percent.
16 The safety goal doesn't actually 17 specifically address workers, but the RIDM report 18 proposes that the worker risks be small compared to 19 others, but not as small as for the public who are not 20 trained or equipped in radiation protection.
21 So, this table is just a summary, and I've 22 organized the quantitative health guidelines into 23 three levels of harm, acute fatality, latent cancer 24 fatality, and cancer illness. The table then shows 25 the different risk criteria thresholds proposed for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
31 1 each level of harm, both to the public and the 2 workers.
3 For example, the point at which acute 4 fatality becomes unacceptable is when it is greater 5 than five E to the minus seven fatalities per year, 6 and, of course, the RIDM report itself goes into great 7 detail about the basis for this criteria. Next slide, 8 Bernie?
9 This slide presents our basis for using 10 surrogate measures in place of the proposed QHGs, the 11 qualitative health guidelines. In a PRA of a nuclear 12 power plant, there are three levels of analysis.
13 Level one is determination of core damage 14 frequency, we call that CDF, and large early release, 15 LERF, or we call that LERF. Level two is 16 quantification of the release of radiological 17 material, and level three is determination of health 18 effects from the releases.
19 However, nuclear power plant PRAs, which 20 are quite mature, and use risk-informed applications 21 for the current fleet, and not currently taken to 22 level three, but rather use the surrogate of CDF and 23 LERF to support risk-informed applications because 24 those values are more feasible to determine. The 25 basis for accepting those surrogate measures is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
32 1 spelled out in NRC Reg Guide 1.200.
2 So, in a like vein, PNNL proposes the use 3 of surrogates in place of the 2008 RIDM report QHGs by 4 formulating limits in terms of radiological dose and 5 likelihood pairs. This provides advantages such as a 6 reduction in calculational burden by eliminating 7 determination of health effects, and as you pointed 8 out, Tom, you know, it's worth remembering that along 9 the transportation route, the population is in 10 constant flux.
11 The second advantage is that the dose 12 limits can be compared to other federal and 13 international dose limits used in related contexts for 14 a perspective like the worker dose limits. Thirdly, 15 determining likelihood and consequences separately 16 provides a greater level of information for decision 17 making rather than combining them into an accepted 18 value.
19 So, PNNL examined the use of dose 20 consequence-likelihood pairs that are used to evaluate 21 risk in other applications. NEI, the Nuclear Energy 22 Institute, NEI, 18-04 guidance uses this concept for 23 risk-informed licensing of advanced non-light water 24 NPPs, nuclear power plants, which have been endorsed 25 by the NRC, and Department of Energy, DOE Standard NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
33 1 3009 guidance uses this concept in their semi-2 quantitative risk ranking approach in support of 3 nuclear safety of non-reactor nuclear facilities.
4 Guidance in these two NUREGs and 10 CFR 5 Part 70 are used in integrated safety analysis for 6 determining performance requirements for nuclear fuel 7 cycle facilities, and lastly, the Q system in Appendix 8 1 of the International Atomic Energy Agency's specific 9 safety guide, SSG-26, uses a reference dose to 10 determine a quantity limit of radionuclides in a Type 11 A package. So, for example, this slide shows 12 hypothetical risk evaluation guidelines for radiation 13 dose that were generated based on guidance for 14 performance integrated safety analysis.
15 The table was developed by putting 16 together the radiation dose levels defined in 10 CFR 17 Part 70 for high and intermediate consequences for the 18 work and individual members of the public, and 19 frequency definitions for unlikely and highly unlikely 20 events at 1-E minus five and 1-E minus six per year.
21 The table is a little bit hard to 22 interpret if this is the first time you've seen it, 23 but you can see that use of discrete frequency and 24 radiation dose pairs in this way creates intervals 25 between the defining points.
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34 1 So, I'll show you in the next slide how 2 this looks graphically, but for the moment if we look 3 at that middle row, it indicates that if the frequency 4 is less than 1-E minus four per year and greater than 5 1-E minus five per year, and the radiation dose to a 6 member of the public is greater than or equal to five 7 rem and less than 25 rem, then the risk is acceptable.
8 And applying the limit in this way creates this 9 stairstep shape when you plot it on a graph, so I'm 10 going to show you in the next slide --
11 MEMBER REMPE: Before you go to the next 12 slide, I just want to make sure I understand what 13 you've done in how you estimated the dose. Am I to 14 assume the exposure is a 50-year exposure for the 15 person, and then Tom mentioned what's the zone, so how 16 far was that person? If it's a worker, I assume it's 17 closer than the public. Could you talk a little bit 18 about --
19 MR. COLES: We actually have a slide later 20 where we talk explicitly about how we calculate the 21 consequences to the worker and the public. There's 22 actually a couple slides.
23 MEMBER REMPE: And the justification for 24 making those assumptions, okay?
25 MR. COLES: Yeah, we --
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35 1 MEMBER REMPE: That's great. Thank you.
2 MR. COLES: Next slide, Bernie? So, this 3 graphic form is a little easier to absorb. This slide 4 shows the same hypothetical risk evaluation guidelines 5 as the last slide for the public. You can see that 6 the criteria forms this shape, stairstep shape when 7 plotted in graph form.
8 So, if the calculated risk of interest 9 when plotted on the chart falls in the blue shaded 10 region, then the risk is determined to be in the 11 acceptable range, and if the risk falls above the blue 12 line, then the risk is considered to be in the 13 unacceptable range.
14 These same kinds of criteria are used in 15 the document of safety analysis for DOE non-reactor 16 nuclear facilities to identify when nuclear controls 17 are needed. In a like vein, the same or similar 18 criteria is used in NEI 18-04 to support risk-informed 19 licensing of advanced non-light water NPPs, which we 20 show in the next slide.
21 So, this is a slide directly from NEI 18-22 04. It shows the risk guidance in short form referred 23 to as the frequency consequence targets. You can see 24 it's more complex than the previous chart, but the 25 concept is the same.
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36 1 And there are different ways this chart is 2 used in assessing individual risk, but for the sake of 3 this example, license basis events whose consequence 4 and likelihood define a point that falls above the 5 blue line are in the acceptable region again and 6 events whose consequence and likelihood define a point 7 that falls below the blue line are in the acceptable 8 range.
9 There are further considerations such as 10 the impact of modeling uncertainty that need to be 11 addressed, but in general, use of the criteria in this 12 way is a way to essentially control risk below the 13 blue line. NRC has endorsed this approach. Go ahead.
14 MEMBER BIER: Okay, I have a couple of 15 questions, and it's not really about any one of these 16 graphs, but about the whole philosophy of them, and I 17 realize these are pretty commonly used. For 18 simplicity, why don't we go back to the previous slide 19 just because it's easier to read? Great.
20 So, for a given risk analysis like what 21 you did for Pele, you would generate not a point, but 22 a like complementary cumulative or something that 23 would be judged against this or --
24 MR. COLES: Right, we'll describe it in 25 more detail, but what we do is define bounding NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
37 1 representative accidents, this is kind of a smaller 2 set of accidents, and then we plot those on --
3 MEMBER BIER: Okay.
4 MR. COLES: -- the graph.
5 MEMBER BIER: Because like I said, I 6 realize this is a pretty common approach, but I've 7 never been completely comfortable with it, so, I mean, 8 two issues. One is just that the black and white 9 division between acceptable and unacceptable seems 10 maybe a little harsh or whatever.
11 But more to the point, let's say we have 12 plotted the risks and, you know, there is one point, 13 one scenario that falls just slightly above the blue 14 region, but all of the others are way down below the 15 blue dividing line, and it seems to me like that does 16 not make that design that was analyzed unacceptable.
17 Really, the higher risk in one area is more than 18 outweighed by very, very low risk comparisons in other 19 areas, so I'd just be curious to have your thoughts 20 about that or comments.
21 MR. COLES: Yeah, that's a really good 22 setup for later in the presentation. We're going to 23 show you exactly that example and, you know, just as 24 a preamble to that, you know, the concept of certainty 25 has to understood --
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38 1 MEMBER BIER: Yeah.
2 MR. COLES: -- right? That's part of it, 3 and then because this is an exemption process, you 4 know, if you are right above the line, you know, 5 there's a way in which we can use controls.
6 MEMBER BIER: Okay.
7 MR. COLES: Yeah.
8 MEMBER BIER: Maybe I'll wait and come 9 back to this then later --
10 MR. COLES: Yeah.
11 MEMBER BIER: -- when you get to those 12 slides.
13 MR. COLES: Good question.
14 MEMBER ROBERTS: This is Tom Roberts 15 again. I have a question related. If you could go 16 back again to the previous page? The NEI standard for 17 the LMP-based approach, which is risk assessment, has 18 a requirement that serves for cliff edge effects.
19 MR. COLES: Yeah.
20 MEMBER ROBERTS: So, you're required to go 21 beyond the five times ten to the minus second 22 frequency to see if there is something just off the 23 range of probability that would have a huge change in 24 result.
25 I didn't see any discussion of that in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
39 1 this report, and you'll get to it, but criticality 2 excursion seems like it would tend to fall in that 3 category because it's definitely in the neighborhood 4 of five times ten to the minus second, and you chose 5 to not look at the consequence because it was straight 6 up the --
7 (Simultaneous speaking.)
8 MR. COLES: We will --
9 MEMBER ROBERTS: So, I wonder what the 10 thought is on cliff edging.
11 MR. COLES: Yeah, we actually mirror your 12 comment in a couple more slides.
13 MEMBER ROBERTS: And we'll discuss --
14 MR. BLEY: Hey, if everybody could stay on 15 the microphones, it would help those of us outside the 16 --
17 MEMBER ROBERTS: Sorry about that, my 18 fault, my fault.
19 MR. COLES: So, one thing I should 20 mention, the NRC has endorsed this 18-04 approach in 21 the next slide that we're looking at, but they do 22 provide the caveat this figure does not represent risk 23 acceptance criteria or actual regulatory limits.
24 Nonetheless, the figure does provide a way to help 25 demonstrate that the risk is acceptably low, but we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
40 1 are going to come back to your comments in a slide or 2 two. Next slide?
3 So, to develop our proposed risk 4 evaluation guidelines, right, we first synthesize a 5 set of limits using the likelihood-consequence pairs 6 from or based on the applications we investigated for 7 facilities as we discuss.
8 There are some examples of using a risk-9 informed approach for the transport of a package, we 10 discussed earlier, but risk evaluation criteria were 11 not developed in these cases. Facilities are 12 stationary, of course, and not subject to 13 transportation hazards. On the other hand, the TNPP 14 will not be operating during transport.
15 So, given there are no risk-informed 16 guidance for transportation PRA, we drew from facility 17 experience to develop our proposed risk evaluation 18 guidelines, and also we propose that transportation-19 specific hazards can be addressed in the PRA.
20 So, then we, to develop these guidelines, 21 then we converted the likelihood and radiological dose 22 consequence limits to health effects using conversion 23 factors published by DOE to convert radiation dose to 24 mortality and morbidity. The source of these 25 conversion factors precisely is the bottom of that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
41 1 slide.
2 Then as a third step, we readjusted some 3 of the likelihood-consequence pairs to ensure that 4 each limit was less than or approximately equal to the 5 qualitative health guidelines that were proposed in 6 the NRC RIDM report, acute fatalities being the most 7 limiting case. We believe this process that we use 8 resulted in a conservative set of likelihood-9 consequence pair limits. Next slide.
10 Okay, so this slide shows the proposed 11 risk evaluation guidelines. The blue figure on the 12 left is for a member of the public at a defined 13 distance from the accident assumed to be maximally 14 exposed. We're going to go into more detail in 15 several slides forward.
16 The orange figure on the right is for the 17 worker who is generally assumed to be closer than a 18 member of a public, typically one meter. The term 19 workers indicate individuals who are part of the 20 radiation protection program and could receive an 21 occupational dose.
22 The likelihood is presented in accidents 23 per year. The radiation dose levels are provided in 24 total effective dose equivalent, which is the 25 integrated committed dose to all organs, which NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
42 1 accounts for direct exposure as well as the 50-year 2 committed dose.
3 We implemented our demonstration PRA based 4 on a single shipment. To compare the risk of multiple 5 shipments of the same package against these 6 guidelines, the accident frequency would need to be 7 increased proportionately.
8 In the proposed risk evaluation 9 guidelines, if the accident frequency is 5E to the 10 minus seven per year, then the risk of the accident 11 scenario is generally acceptable. However, as Tom 12 pointed out, if the accident frequency is less than 13 the 5E to the minus seven per year, it should be 14 evaluated to confirm there are no cliff edge effects.
15 MEMBER REMPE: So, again, I'm trying to be 16 patient here, but are you still planning to tell me at 17 some point what you assume for the exposure duration 18 for the worker and the public, and specific factors?
19 MR. COLES: I am.
20 MEMBER REMPE: Is that coming up in 21 another slide? I was looking at the rest of the 22 slides and I just can't figure out where it's coming, 23 but you --
24 MR. COLES: Well --
25 MEMBER REMPE: -- you won't forget.
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43 1 MR. COLES: I won't, and specific, if you 2 want to look ahead, it is in step six of the --
3 MEMBER REMPE: Okay.
4 MR. COLES: So, slide 24 or something like 5 that. It's a bit ahead.
6 MEMBER REMPE: Okay, that's fine. I'm 7 sorry. I just didn't want to lose it because it 8 looked like you were getting to another concept.
9 MR. COLES: So, this slide shows our 10 process for using PRA. The primary difference -- I 11 know Dennis is on the line. The primary difference 12 between our process and a conventional PRA used for 13 reactors, for example, is that we use the accident 14 development process to select and define the bounding 15 representative accidents, which I'll describe in 16 detail a little later, and then we determine the 17 likelihood-consequence for those bounding 18 representative accidents.
19 And I recognize this figure is hard to 20 read. I just present it to give you a sense of the 21 overall process. I'm going to just name the steps and 22 then we're going to talk about each one in detail.
23 It's a compilation of the TNPP design and shipment 24 route information.
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44 1 safety functions, and there's identification and 2 development of accidents, selection of the bounding 3 representative accidents, and then we develop the 4 likelihood and we develop the consequence for each 5 PRA, and then we compare the results to the risk 6 evaluation guidelines, and we assess sensitivities and 7 uncertainty, and then we assess defense-in-depth and 8 safety margin. Next slide. This slide shows step 9 one. This is --
10 MEMBER MARCH-LEUBA: Excuse me, this is 11 Jose. Can you go back to the -- it's something that 12 you said about the one reactor versus 100 reactors.
13 If I -- if there is a centralized factory somewhere 14 in, say, Ohio, that produces all of these reactors and 15 ships them all over the world, on a legally accessed 16 road to this facility, all 100 of those go by my home 17 a year. How do we factor that on the acceptance 18 criteria? I mean, do we reduce the frequency by the 19 expected number of reactors that would travel near my 20 house?
21 MR. COLES: Well, that's a really good 22 question and there are some complexities to applying 23 the guidance that would need to be sorted out if we 24 started talking about multiple reactors and multiple 25 shipments per year and how would that be done in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
45 1 practice. It's a very good question. How would you, 2 like, track the risk if a reactor is moved a number of 3 times a year? Those questions, although we discuss it 4 a lot internally, we haven't sorted those out.
5 MEMBER MARCH-LEUBA: Yeah, the problem 6 conceptually is that I can ask good questions. You 7 are tasked with providing the answers for them on your 8 documents. I mean, I'm the lucky one.
9 MR. ADKINS: There you go. One of the 10 comments we'd make to that too is when they're 11 deployed, obviously they would be green or non-12 utilized, right, and so there's a lot of things to 13 take into consideration, especially when you're 14 retrieving them to recycle or disassemble, dismantle.
15 MEMBER MARCH-LEUBA: Especially the used 16 ones, yes.
17 MR. ADKINS: Yeah, exactly, exactly, and 18 so we were looking at that as being partially beyond 19 the scope of what we are trying to show as the pathway 20 and process, and quite literally, this would tie back 21 to the vendor and their responsibility to submit 22 something to the NRC that would prove without a doubt 23 that they were maintaining reasonable assurance of 24 adequate safety through their process and their 25 concept definition, right, so I guess we left that to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
46 1 the reader.
2 (Simultaneous speaking.)
3 MEMBER MARCH-LEUBA: Can you talk closer 4 to the microphone? We can't hear you.
5 CHAIRMAN BALLINGER: Yeah, what happens is 6 when you're closer to the microphone, everybody hears 7 you. When you back up a little bit, nobody hear you.
8 But how is that question different than shipping spent 9 nuclear fuel?
10 PARTICIPANT: Exactly.
11 MR. COLES: It's not --
12 MEMBER PETTI: I mean, that could be 13 handled with the manufacturing license --
14 PARTICIPANT: Exactly.
15 MEMBER PETTI: -- right? I mean, I could 16 obviously --
17 PARTICIPANT: Yeah, exactly, yeah.
18 MEMBER PETTI: Let's say I'm taking the 19 shipment back to where it was manufactured.
20 PARTICIPANT: Sure.
21 MEMBER PETTI: Then it could be 22 encompassed in their safety analysis --
23 PARTICIPANT: And --
24 MEMBER PETTI: -- as sort of, you know, 25 it's the equivalent of co-located hazard, right, where NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
47 1 there's a chemical plant or something.
2 PARTICIPANT: Right.
3 MEMBER REMPE: But is that coordination 4 going on at NRC? I mean, we're trying to develop 5 stuff for the manufacturing license at the same time 6 as the shipping, and so that's a good thing that NRC 7 ought to be thinking about.
8 MR. WHITE: Bernie White, NRC staff. It 9 absolutely is something we're thinking about. And so, 10 I think you brought up the fundamental difference 11 between reactors and transportation, although you 12 haven't necessarily explicitly stated it, in the fact 13 that spent fuel shipment, as was discussed, you know, 14 those packages meet the regulations in 10 CFR Part 71.
15 There's containment criteria, which I have a big slide 16 on I'll probably skip now that I'm talking about it, 17 and there's dose rate criteria.
18 The risk assessments that we've done in 19 the past have shown if you meet those, and when I say 20 meet those, so under normal conditions of transport, 21 there's a release of we would say less than ten to the 22 minus six to A2 per hour, so a millionth of an A2, and 23 A2 is the maximum quantity authorized in a Type A 24 package, and for accident conditions, it's an A2.
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48 1 how much material is released to no more than five rem 2 in an accident at most, and you've limited the direct 3 dose to an individual because the dose rate is limited 4 in shipment. You know, it's ten MR per hour from the 5 walls of a vehicle.
6 You know, I'm talking a spent fuel 7 package, so it's probably a train or a truck. It's an 8 exclusive use shipment, and so it's, you know ten MR 9 per hour two meters from there or one R per hour in an 10 accident.
11 You know, one R per hour, you'd have to be 12 there a pretty long time to get a significant dose 13 that would cause, you know, significant injury.
14 Chances are first responders would show up and cordon 15 off the area like they're supposed to before that.
16 And so, you know, when we do risk 17 assessment in transportation, we don't know where the 18 packages are going to go. We don't -- I mean, because 19 it could be anything from a spent fuel package to a 20 radiography camera. Radiography cameras are shipped 21 all over the world, all of the U.S. every single day, 22 and they have the same radiation requirements as spent 23 fuel packages do.
24 The -- and I'm trying to be curt here a 25 little bit, but when you look at how a transportable NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
49 1 micro-reactor is going to be shipped -- you know, you 2 brought up what up if it's, you know, 100 reactors 3 come out of a factory and ship worldwide? Well, 4 therein lies the problem.
5 To ship worldwide, it's just not the NRC 6 and the DOT that have to accept the approval of that 7 package. It's also foreign competent authorities, and 8 therein lies kind of the issue that we in the staff 9 are struggling with.
10 We don't know what -- we don't have 11 analysis for transportable micro-reactors and how they 12 fair in a 30-foot drop, for example. What do they 13 release? We haven't had those discussions yet, but 14 whatever NRC approves would have to be accepted by a 15 foreign competent authority for import shipment into 16 that country, which is different from a reactor.
17 MEMBER MARCH-LEUBA: Yeah, my comment was 18 not as it cross from the border into Canada. It's as 19 it comes out of the facility and drives to my home in 20 Ohio, which there is only one road to the facility and 21 all of them go through there.
22 Let me give you a cheap and dirty solution 23 that I would like you to consider. My claim is that 24 transporting one reactor through my home at the exit 25 to the factor has the same probability of failure, the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
50 1 same risk as transporting 100, exactly the same, and 2 the reason is if you're shipping the reactor by my 3 house and you have an accident, and you cause a five 4 rem to somebody, you are not going to ship the other 5 99 after that. You're going to stop shipping and fix 6 it.
7 So, the fact that you will -- you have 8 plans to ship 99 more, those were plans. It's not 9 going to happen. So, the fact that you have plans to 10 ship 99 does not increase the probability of an 11 accident happening.
12 MEMBER REMPE: And furthermore, you'd nuke 13 the house, but you couldn't sell the property.
14 (Laughter.)
15 MEMBER MARCH-LEUBA: Yeah, yeah, and that 16 brings the issue that we've always held with multiple 17 reactors in a single site. When you do the PRA, we 18 tend to do the PRA for a single unit because it's 19 easier, and the issue with multiple reactors at a 20 single site is that you could have common cause. You 21 lose power, offsite power and you don't lose one unit.
22 You lose three units.
23 So, when we move this concept to the 24 transportation, it would be nice if we could require 25 that you only transport one reactor at a time. Don't NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
51 1 load a train with 12 because if you do load a train 2 with 12 reactors and you have an accident, then you 3 have 12 times the dose, but if you ship them one at a 4 time, the moment you have an accident, you don't ship 5 anymore. Anyway, that's my five cents, over and out.
6 PARTICIPANT: Thank you.
7 MEMBER REMPE: Before you finish talking, 8 Bernie, could you -- you were talking about so many MR 9 per hour and the rem that has to be released, which is 10 really curies coming out, and someone's assumed a 11 certain location and an exposure time. What do you 12 guys assume on that?
13 MR. WHITE: You mean for Pele or for 14 actual --
15 MEMBER REMPE: Just what you're doing, 16 because I assume it's the same. I mean, what do you 17 do when you're --
18 MR. WHITE: Right.
19 MEMBER REMPE: -- releasing a certain 20 amount of --
21 (Simultaneous speaking.)
22 MR. WHITE: So, we tend to talk in A2s, 23 and the reason we do that is because we don't know 24 what any particular package is going to carry when we 25 set up the regulatory requirements. For example, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
52 1 cobalt has an A2 value of something like 11 curies.
2 Plutonium's on the order of 20 millicuries, and so 3 they're different, and the idea is they would give you 4 the same dose in the event of an accident.
5 MEMBER REMPE: You must be assuming a 6 person is at a certain location for a certain --
7 MR. WHITE: Right, and that's --
8 MEMBER REMPE: -- for a certain amount of 9 time --
10 MR. WHITE: And that's all baked --
11 (Simultaneous speaking.)
12 MR. WHITE: Right, and that's all baked 13 into the Q system.
14 MEMBER REMPE: The Q system.
15 MR. WHITE: The Q --
16 MEMBER REMPE: Two regular reactors --
17 (Simultaneous speaking.)
18 MR. WHITE: Right.
19 MEMBER REMPE: Yeah, okay.
20 MR. WHITE: The key system was developed 21 by IAEA for, particularly for transport of radioactive 22 material. It looks at five different pathways. I'm 23 going from memory here. I have a slide later. We 24 both have slides on this.
25 MEMBER REMPE: And you'll give me --
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53 1 MR. WHITE: Yeah, yeah.
2 MEMBER REMPE: Because I've looked ahead.
3 I don't see it, distance, exposure time, and --
4 MR. WHITE: Right.
5 MEMBER REMPE: -- I'm curious because 6 again, people could be moved off.
7 MR. WHITE: Right, and so we didn't bake 8 that into our review. What we said is PNNL will 9 presume 25 meters from an accident, and the reason 10 they presume that is because of first responders.
11 However, you could have an accident that happens 12 before a first responder gets there, which is normally 13 the case.
14 However, there could be mitigating 15 compensatory measures such as rolling road closures.
16 You know, if you don't allow vehicles within 25 meters 17 of that, the closest person could be within 25 meters 18 depending upon where houses and things sit off the 19 roadways. That would have to be looked into, you 20 know.
21 MEMBER REMPE: So, it's a sophisticated 22 analysis --
23 MR. WHITE: Which is fairly route-24 specific.
25 MEMBER REMPE: Okay, and again, for a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
54 1 worker, they're assuming that they would put on some 2 PPE within a day or something like that?
3 MR. WHITE: So, the workers would likely 4 be, if there are workers, the truck driver and 5 escorting individuals. First responders are not 6 typically considered workers. They're considered, you 7 know, members of the public. They would typically 8 wear PPE for a Type B fissile package in an accident.
9 That's what the emergency response guidebook says for 10 that type of response.
11 But what you'll hear in our presentation, 12 in the staff's presentation is that PNNL said some 13 really good things and we like what they said.
14 However, the details are what's important. How close 15 can a person actually be in the event of an accident?
16 We don't know that from this.
17 MEMBER REMPE: Okay.
18 MR. WHITE: We may know that when we get 19 the application in and we see compensatory measures 20 that say you have escort vehicles. You know, you 21 don't allow anybody within ten meters or 20 meters, 50 22 meters. And that may be needed to meet the normal 23 conditions of transport dose rate. We haven't 24 evaluated that yet.
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55 1 designs look like, so we're trying to approve, you 2 know, a methodology at a high level where really the 3 details is what we're going to get over the next few 4 years. And as the old saying goes, and I have it on 5 the presentation, the devil's in the details.
6 MEMBER REMPE: Yeah.
7 MR. WHITE: You don't know how that's 8 going to shake out, you know, so we're trying to look 9 at it from, I'd say, the 50,000-foot level. Can it 10 get us where we need to go? Yeah, will it? Maybe, it 11 depends.
12 MEMBER REMPE: This helps. Thank you.
13 MR. WHITE: Okay.
14 MEMBER REMPE: Go ahead.
15 CHAIRMAN BALLINGER: You do have a data 16 point, naval reactors.
17 MR. WHITE: We do have a data point.
18 However, we're not privy to that data because naval 19 reactors ships under its own authority and they don't 20 share that with us, and naval reactor packages meet 21 Part 71 in their entirety.
22 CHAIRMAN BALLINGER: They do.
23 MR. WHITE: They do, absolutely.
24 CHAIRMAN BALLINGER: They have 25 compensatory measures that they apply.
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56 1 MR. WHITE: They do --
2 CHAIRMAN BALLINGER: Yeah.
3 MR. WHITE: -- but they're not because of 4 the package approval.
5 CHAIRMAN BALLINGER: Ah.
6 MR. WHITE: Okay? The package approval 7 meets Part 71 in its entirety, so they're not needed 8 for our approval.
9 MR. COLES: So, Joy, just to go, I'll just 10 mention though in our demonstration PRA, we assume 11 that the worker is one meter, and that's consistent 12 with the methodology and the IAEA guidance that we 13 use.
14 And the public, we do recognize that there 15 are some uncertainties, as was mentioned, about where 16 the public may be located, but we use the distance, 17 the standoff distance required by the Department of 18 Transportation when you're moving high-level 19 radioactive material, up to 25 meters, but we do a 20 number of sensitivity studies, right, in the 21 demonstration.
22 So, one of the things that's important, 23 and I think you kind of alluded to it a number of 24 times, is that the distance away from the point of the 25 release is a key parameter, right? So, we've done NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
57 1 sensitivity studies on that parameter. For this 2 demonstration, I'm not saying what happened in the 3 other case, but for this demonstration, that distance 4 didn't make a big difference.
5 So, I'll pick up where we left off. I 6 think Bernie was at that one. I think we talked about 7 step one. Step two is identification of package 8 safety functions. So, as you'd expect for a package, 9 it includes providing containment of radiological 10 materials, providing radiation shielding, maintaining 11 criticality-safe configuration.
12 Regarding the fourth bullet there under 13 step two, maintaining passive transfer of decay heat 14 during transportation, this wasn't considered because, 15 again, this is isn't a package. This is a reactor, 16 and it wasn't initially clear whether or not this 17 could be a safety function. It turns out for this 18 demonstration design, loss of passive heat transfer is 19 not a safety function, and so if you lost it, you 20 wouldn't get an accident.
21 MEMBER REMPE: I have a question about 22 this, too. In Part 53, one of the things that I like 23 is that the staff did the critical safety functions.
24 They had, you know, we're the nuclear regulatory 25 agency, we're going to have the top level line B, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
58 1 contain radiation. And then they had lower level ones 2 that challenge radiation containment.
3 In your case, radiation shielding and 4 contain radiation, to me, are the top level ones. And 5 then there's a bunch of other things that could 6 challenge that. And, yeah, okay, you said, well, we 7 considered passive cooling but for this particular 8 design it wasn't important.
9 Since we're kind of looking at a broader 10 approach, and not just particularly on this design, 11 why not touch some other things that ought to be 12 considered like control chemical reactions? As Member 13 Halnon mentioned, you might have sodium, you might 14 have molten salt. And I think that it might be good 15 to broaden things a bit.
16 MR. COLES: Right. That's exactly why we 17 do this step; right? The point of this step is to 18 understand what the safety functions are. Because 19 this is going to inform, then, our identification and 20 development of accident scenarios. That's the only --
21 MEMBER REMPE: They don't pester the 22 analysis, I know. I saw that in the document. What 23 I didn't see was consider other challenges that 24 should, should be, you know, thought about, even if 25 you can dismiss them for this particular design.
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59 1 MR. COLES: Well, that, that --
2 MEMBER REMPE: Although there's beryllium 3 in there, there's tungsten in there, there's graphite 4 in there. I didn't see that. But, of course, this is 5 one document. I'm sure there's other documents I 6 haven't seen. But I just thought it ought to be 7 mentioned.
8 If staff is doing an evaluation of, a 9 high-level evaluation of the methodology, I think it 10 ought to be mentioned.
11 MR. WHITE: So, Bernie White, NRC staff.
12 So, from our typical parlance we fact test 13 three safety functions: containment, radiation dose, 14 and criticality safety.
15 How you get there is a lower level 16 function.
17 For a typical package we look at a 30-foot 18 drop, puncture test, fire test, and immersion test.
19 While a lot of that seems mainly structural and 20 thermal, we do look at packaging components. We look 21 at the contents, how the packaging components interact 22 with one another from a materials perspective. We 23 look at the contents, how it interacts with itself for 24 materials, you know, for material. And how it 25 interacts with the package.
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60 1 You know, we have package approved for 2 uranyl nitrate. We would look at that. How, what 3 facet was it contained in, the liquid, how does it 4 interact, what material aspects could degrade the 5 package such that when it's shipped, if it were in an 6 accident would it maintain those three safety 7 functions of containment, radiation shield 8 criticality, safety.
9 So, we would look, the staff would look at 10 that as part of the package application.
11 MEMBER REMPE: Yeah. Just it's always 12 good to have it in writing. And I didn't see it in 13 writing. And that's what I've been asked to look at 14 to prepare for this meeting.
15 MR. COLES: Well, let's go to the next 16 slide. And there might be an answer to your question 17 partly addressed in this slide.
18 So, this slide shows steps, which is the 19 identification, development of accidents. We use 20 hazards analysis to perform the step because it is, 21 because it is a comprehensive way to investigate what 22 can go wrong.
23 So, that's the whole purpose of doing the 24 hazards analysis: we want to understand, like you 25 said, the samples you used were very good, what can go NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
61 1 wrong?
2 And so, we start with the, you know, 3 hazard I.D. checklist. We, we -- given that the --
4 Did you want to say something?
5 PARTICIPANT: No.
6 MR. COLES: Thank you. Given that the 7 accident scenarios are not complex, though, like in a 8 reactor, fault trees and event trees that are typical 9 here for reactors weren't used because of the, the 10 absence of active and passive systems redundancy.
11 Hazardous conditions were defined as 12 conditions leading to the release of radioactive 13 material or degraded shielding.
14 So, what you'll find as you go further, 15 we, on the accidents we defined has nothing to do with 16 that collision on the highway. It has nothing to do 17 with transfer. It has to do with human error or 18 mechanical failure or isolation devices, for example.
19 Worksheets were completed for possible 20 hazard categories. Includes fire, explosion, kinetic 21 energy potential, and loss of containment events, 22 direct radiological exposure events, criticality 23 events, manmade external events, and natural 24 phenomena.
25 Highway scenarios include events such as NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
62 1 collisions with vehicles or objects, collisions and 2 subsequent fire, non-collisions such as rollovers and 3 jack-knives, non-crash events involving externally 4 initiated fire. Non-highway scenarios include events 5 such as operator error, mechanical failure, isolation 6 devices, and fires that are initiated internally.
7 A total of 31 different accident scenarios 8 representing eight different actual phenomena were 9 defined.
10 So, this slide shows Step 4, which is 11 defining the bounding representative accidents from 12 the list of potential accidents derived from the 13 hazardous condition evaluation. A BRA, sometimes I'll 14 say B-R-A, and I mean bounding representative 15 accident, is representative of a group of accident 16 scenarios that are phenomenologically similar.
17 The likelihood for a BRA is determined by 18 the sum of the accidents in the group. The 19 consequence of a BRA is determined by the worst 20 consequence of the accidents in the group.
21 By using this approach to define BRAs, 22 that bounds the risks of all accidents in that group.
23 There were a total of 13 BRAs defined from this 24 demonstration. BRA.
25 Next slide. This is actually the bounding NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
63 1 representative accidents. You can read those on your 2 handout. I'm not going to go over them. But, in 3 general, they consist of impacts of different 4 severities, fires, impacts and fire, non-impact 5 crashes, non-impact package failures and criticality.
6 Next slide. This slide shows Step 5, 7 which is development of the likelihood for each BRA 8 graded for very large trucks greater than 26,000 9 pounds were used, when available, to determine the 10 frequencies of different types of accidents defined by 11 the bounding representative accidents. Though, we 12 anticipate the actual weight will be greater than 13 150,000 pounds. But this is the best available data, 14 and it's likely conservative and prior to a much 15 larger vehicle.
16 Route-specific data for large truck 17 accidents for the five states of the assumed route, 18 hypothetical route, were augmented by nationwide 19 statistics. In many cases there was not enough route-20 specific information to develop an accident frequency.
21 So, nationwide data was used to develop split 22 fractions that were used in conjunction with the 23 route-specific data.
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64 1 from the Motor Carrier Management Information System 2 and the Fatality Analysis Reporting System we call 3 FARS.
4 The second set of data approaches used to 5 estimate package-specific failure likelihoods: crash 6 events, as we mentioned, human errors, and mechanical 7 failures.
8 And then a third set was used associated 9 with route-specific hazards such as distance of bodies 10 of water, steep drop-offs, which I'm going to show you 11 on the next slide.
12 So, this slide shows the assumed 13 hypothetical route from Idaho National Labs to White 14 Sands, New Mexico. Almost entirely interstate along 15 a 1,300 mile route.
16 The GIS data search scripts and Google 17 Street Views images were used to identify portions of 18 the route where a hazard existed to compute the 19 percentage of the length of those portions to the 20 total length. We can see on the map, I think, that 21 there are bodies of water and mountainous regions; 22 right?
23 So, we used this to look at two different 24 kinds of hazards, that when I say "this" I mean GIS, 25 of steep drop-offs. If an accident occurs here, the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
65 1 truck and the truck and the package could drop or roll 2 to a lower elevation. This could result in 3 significant impact sustained to the package.
4 Also, we looked at locations where there 5 was sufficient slope to a body of water deep enough to 6 submerge the reactor vessel. If an accident occurred 7 here, criticality might occur for the, for the 8 demonstration design.
9 First, a script was written to search for 10 these locations. Then the route-specific very large 11 truck crash rate was multiplied by the percentage of 12 the route where the hazard exists to get a final 13 accident frequency for that, involving that particular 14 hazard.
15 Lastly, a physical road survey was 16 performed to confirm treatment of identified hazards 17 and to identify locations for safe havens.
18 MEMBER REMPE: Let me ask a question here.
19 And, again, I'm going with what's in the report that 20 the staff was looking at that. I see on page 192 out 21 of 354, and it's talking about how you calculated the 22 frequency.
23 And I guess the assumption that concerned 24 me was that you assumed that the accidents are 25 randomly distributed. But, again, I would have to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
66 1 assume you're moving that package around on the side 2 in Idaho. So, that's why I was looking at this 3 because I lived in Idaho.
4 Along that road to Utah it's well known 5 that there's a portion of the highway that's elevated 6 and curved. And in cold weather it has black ice on 7 it and the semis always roll over. And I'm just 8 thinking that's not a good assumption if that's part 9 of the road you're probably going to be taking.
10 And is that a common assumption that is 11 used for these types of frequency estimates? Because 12 I don't see a highway analysis, safety analysis, and 13 it kind of concerned me.
14 MR. COLES: So, we don't --
15 MEMBER ROBERTS: I had a related question 16 to this, too, which is this regards the number. I was 17 wondering if you looked at the probabilities or 18 accidents because of congestion in a highly populated 19 area versus other places? Or are there some features 20 you can talk about, geographic features, geological 21 features, whatever, are in those kind of areas that 22 are being reported.
23 MR. COLES: We specifically address the 24 route to go around Denver for that reason, as I 25 pointed out.
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67 1 DR. MAHERAS: Can I?
2 MR. ADKINS: Yes, please. Please do, 3 Steve. And it ties to a number of things.
4 DR. MAHERAS: I'm Steve Maheras at Pacific 5 Northwest National Labs. So, in regards to the 6 routing that was done, we used a tool that generates 7 routes that would be used for spent nuclear fuel. So, 8 for whatever reason, that route through Denver, which 9 is the state-approved route, goes right through the 10 Mousetrap, right through town. Right?
11 So, we chose to evaluate a route that goes 12 around Denver also as an additional case because of a 13 concern about getting it outside of Denver proper.
14 Right?
15 With regards to the data used, we have a 16 bit of a problem with the ability to discern accidents 17 on specific sets of roads. We can pinpoint the 18 accident just fine. We know the location. But we 19 need to get the denominator in that equation also, 20 which is traffic volume. And that one tends to be the 21 one that's the tougher nut for us to get is the 22 denominator in the accident rate calculation.
23 It's, it's straightforward to define the 24 position of the accident, and it's not as 25 straightforward to get the commodity flow to do the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
68 1 calculation part.
2 MEMBER BIER: I have an additional 3 question, which is probably more for staff than for 4 PNNL.
5 In this analysis, obviously, this was done 6 for a specific transportable reactor. And you knew 7 most likely at least where it would be coming from or 8 where it would be going, so you could do this very 9 detailed analysis of routes.
10 In future, if we have transportable 11 reactors for other purposes we may not know at the 12 time where it's origin, even where the destinations 13 are. Or, they may be moved from one location to 14 another.
15 Somebody recently contacted me with an 16 interest in using transportable reactors 17 hypothetically eventually for fracking, where it might 18 be moved, say, from one oil well to another, you know, 19 in, in the same state, you know, in North Dakota, or 20 in Texas, and maybe in a totally flat part of the 21 country where this kind of topography would not even 22 occur, or where you could never get black ice if it 23 was in Texas, or whatever.
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69 1 have to include the possibility of these kind of 2 routes but wouldn't assume detailed knowledge of 3 exactly which road you were going on and where?
4 MR. WHITE: Bernie White, NRC staff. So, 5 the easy answer is yes. However, you know, there's a 6 lot of complicating factors with that. You know, 7 typically in spent fuel transportation, packages go 8 anywhere, any time. Or in transportation, the 9 packages go anywhere any time.
10 If you are using something like this 11 methodology that is extremely specific, that probably 12 would not be the case. You would probably be limited 13 to specific routes, specific locations.
14 Does that mean that that's the only thing 15 we would ever approve? No. If sufficient number of 16 people wanted something like this, a sufficient number 17 of vendors wanted something like this to be approved 18 for a larger number of reactors to be shipped -- when 19 I say "reactors" I don't mean, you know, five Peles.
20 I mean Pele plus reactor by five, six, seven, eight 21 different companies -- we would probably look to do, 22 consider -- I mean, that would probably be a 23 rulemaking that we would probably consider doing to 24 look at the broader picture.
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70 1 because we don't have enough data to warrant us to do 2 that, given what we've heard from transportable micro-3 reactor vendors.
4 CHAIRMAN BALLINGER: So, Dennis has got 5 his hand up, and I don't know for how long.
6 MR. BLEY: Oh, for just a little while.
7 Thanks, Ron. I have two questions I would like you 8 guys to talk through a little bit. The first one 9 deals with the bounding representative accidents. And 10 Chapter 5, pretty thorough as I read it front to back.
11 But my first question is what kind of 12 measures did you guys do from kind of an overview or 13 structural point of view to enhance completeness of 14 this accident, being very careful that you haven't 15 left anything out that could matter?
16 The ones you have here are described 17 really well for me. And then, these words have come 18 up a bunch of times, and maybe you can clarify just 19 what you mean. A script was written to find this or 20 that. Tell me about what that means?
21 MR. COLES: Well, what we're trying to say 22 is about the script. And, Steve Maheras, feel free to 23 jump in. But, because we're using GIS, right, data, 24 there's a way to search the data. And we were 25 interested only in particular locations where NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
71 1 specific, you know, parameters existed that we thought 2 were hazardous. One is a steep drop. If you had an 3 accident at this location, go off the road, you would 4 drop to a lower elevation. The other one had to do 5 with dropping into a body of water.
6 Steve Maheras, would you like to add to 7 that?
8 DR. MAHERAS: Yes, yes. So, instead of 9 trying to find those by hand, using a map perhaps, we 10 used GIS. The script was merely a tool of convenience 11 to search through the GIS data to find the locations 12 of concern.
13 MR. BLEY: Okay, that makes sense. I've 14 never had a chance to look through that and do that 15 myself. But I guess that database is searchable for 16 these things. And that's what you did. It's like a 17 little program to look for the places where these 18 conditions might exist.
19 DR. MAHERAS: If you are clever with tools 20 like Python, et cetera, yes.
21 MR. BLEY: Okay. And the other question 22 is, from a high level point of view what --
23 MR. COLES: Yeah, Dennis.
24 MR. BLEY: -- you've done is complete as 25 possible?
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72 1 DR. MAHERAS: Right. So, Dennis, our 2 intention using, you know, the hazard analysis 3 approach was to be comprehensive. And in the back of 4 the report, if you had a chance to look at it, there 5 is appendices that provides all the hazardous 6 conditions that we identified in a group of subject 7 matter experts.
8 MR. BLEY: Uh-huh.
9 DR. MAHERAS: And there's about -- I think 10 there's about 50 pages of accident scenarios, really, 11 there. We screened a number of those out 12 qualitatively because they didn't produce enough 13 impact for the package, or they just were so 14 incredibly low frequency that we didn't carry them 15 forward.
16 Then of the ones that were left we 17 organized those into 31 accident scenarios, which are 18 listed, I think, on Table Five-four, if memory serves 19 me correct.
20 Then, from there we aggregated those 31 21 down to 13 of bounding representative accidents. We 22 feel that we have looked across the entire landscape 23 for accidents, and that these bounding representative 24 accidents are bounding enough and representative 25 enough of accidents that can occur.
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73 1 MR. BLEY: I guess where I was pointing to 2 is the breadth of the search by your large number of 3 experts is the basis.
4 What did you do to try to make sure -- and 5 this is a hard thing to do sometimes -- try to make 6 sure the experts have considered this broadly enough 7 to take off all of the important possibilities?
8 DR. MAHERAS: Right, I understand your 9 question, Dennis. I mean, that, that is the purpose 10 of hazards analysis. And we did a couple things.
11 Now, the design actually provided that 12 hazard analysis of a stationary route. So, we, number 13 one, we considered all those.
14 And, number two, we started with a large 15 checklist of hazardous conditions and energy sources.
16 And we considered each one in turn.
17 And then that's how we came up with the 50 18 pages of hazardous conditions that, that are in the 19 appendix. We tried to include in the group people 20 with the appropriate subject matter expertise, people 21 that understood design, people that understood 22 consequence analysis, people that understood the fire 23 hazards and the chemical hazards, for example.
24 MR. BLEY: Okay. Well, that's probably as 25 good as you're going to do. You know, hazard NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
74 1 analysis, I agree, it's the purpose. But it covers a 2 plethora of things that one can do. Some of them help 3 you be very complete, other ones not so much.
4 So, that's a pretty good answer for now.
5 Thanks.
6 DR. MAHERAS: Great.
7 MEMBER REMPE: This is Joy. And I want to 8 bring back my point again about the way you calculated 9 the frequency for the accidents.
10 If you go to page 182 you, you do say, 11 hey, it's only going to be point -- 5.9 miles, about 12 .46 percent of the 1,289 mile route. And so, then you 13 look through and have, that you have the total number 14 of accidents. And then and you multiply that by --
15 and say that there is about 3.9 timber mines, 7 miles 16 potential for an accident, per your frequency. And 17 then you multiply that frequency by .46.
18 And that's my problem is, okay, you 19 figured out what fraction of the distance is where you 20 can have a drop and rollover, but then you took that 21 fraction of the distance and multiplied it to get the 22 frequency of an accident there. And to me, you've got 23 to go through that distance. And I don't think the 24 math is right.
25 MR. COLES: Well, let me say something NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
75 1 real quick to see if this helps. We did -- I mean, I 2 understand your point. Your point, I think, and 3 correct me if I'm wrong, is that the accident rate 4 probably varies along the route. And I think that's 5 your point.
6 So, so what we did is we didn't -- Steve 7 explained that. It's really hard to find the actual 8 accident rate across any segment of the route. So, we 9 used the aggregate crash frequency for the entire 10 route.
11 MR. ADKINS: We should probably speak to 12 the fact that there's tremendous inherent and 13 tremendous conservatism in the numbers that we used 14 because we used, like, small truck accident 15 frequencies as opposed to something that would be of 16 the concepts that we're talking, upwards to 150,000 17 pounds, that are heavy, heavy haul and things of that 18 nature, just to induce some conservatism.
19 And one of the reasons for doing that, 20 which I would let the experts speak to this, is the 21 fact that there was kind of a void in some of these 22 heavy haul truck accident magnitudes, frequencies, 23 things of that nature, that there was an absence of a 24 lot of that data, primarily due to the fact that 25 they're so infrequent in comparison with the numbers NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
76 1 that we've used.
2 Steve, you may have something you want to 3 say?
4 DR. MAHERAS: Yeah. Yeah, so when we say 5 "large truck," right, that's a 26,000 pound truck. We 6 expect a Pele-carrying truck to be around 150,000 7 pounds or so.
8 Trucks of that size require state 9 permitting for every state that they go through. That 10 requires a examination of the route to make sure that 11 the infrastructure can handle that load, both from a 12 capacity of the road, overhead bridges, et cetera.
13 So, we might say large trucks, but they're 14 not Pele large trucks when you talk about the accident 15 rates. And those accident rates tend to be dominated 16 by trucks of approximately 80,000 pounds and less 17 because of the increased permitting requirements that 18 those very heavy loads have.
19 MEMBER REMPE: So, again, I'm not an 20 expert in highway transportation accidents, but it, to 21 me, it seems -- and I'm sure your numbers are 22 conservative -- but if the staff's looking at the 23 methodology, it just, something seems a little strange 24 that you could divide those frequencies by the fact 25 that there's only a small fraction of the road where NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
77 1 you're concerned. It seems like you've got to go 2 through that fraction of the road.
3 And, again, I'll leave it there, but it 4 just doesn't sound like it's right on how to estimate 5 the frequency because I've got to go through that 6 section of the road to find a different route. But, 7 anyway, I'll let it go there.
8 MEMBER BIER: Yeah. One other comment.
9 If I understood correctly, it sounds like 10 you're taking kind of the overall accident frequency 11 for the entire route, which I understand why you have 12 that data, use that data. But there may well be 13 correlations where the part of the road with the steep 14 drop-off above the bottom body of water may be the 15 part where the accident frequency is highest because 16 you're using some curvy route, and the straight shot 17 through a desert that's averaged in with it may have 18 a very low probability of accidents.
19 And that correlation, I don't know whether 20 that correlation is derivative. And I'm also not a 21 transportation expert. But it seems worth looking 22 into.
23 DR. SCHULTZ: Steve, this is Steve 24 Schultz.
25 The question associated with -- I'm over NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
78 1 here. The question you associated with your last 2 response, you indicated conservatism associated with 3 the assumptions that you have, you have made. Do you 4 have a sense on the degree of conservatism that that 5 imparted to go through this.
6 DR. MAHERAS: It's very difficult to tease 7 out from data accidents for loads of 150 or so 8 thousand pounds. So, I would say that we are 9 conservative by probably a factor of 100 to 1,000, 10 just because there are so few accidents involving 11 those very large loads because they're escorted fore 12 and aft, because they have permitting requirements, 13 because in general they're required to us a higher 14 quality road, et cetera.
15 DR. SCHULTZ: That's fine. Without 16 quantifying it, it's an important feature of the 17 overall evaluation. When we look at the, at frequency 18 consequence plus, we're going to have questions about 19 uncertainty associated with where the bullets land.
20 So, that's good information to know.
21 Thank you.
22 DR. MAHERAS: Yeah, and --
23 MR. BLEY: This is Dennis again. I think 24 you guys need to be really careful about these kinds 25 of conservatism. I think the one you just described, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
79 1 yeah, that's pretty strong, that you're taking data 2 from a lot of different kinds of trucks. And probably 3 the class you're looking at has lower accident rates.
4 But what Vicky brought up is what I was 5 hanging on. Most of the things you're concerned with 6 are occurring places where the roads are a little more 7 winding, where I would suspect accidents are quite a 8 bit more likely. So, that's the opposite side of it.
9 So, climbing in a blanket while you have 10 conservatism without some more to back it up seems a 11 little bit of a stretch.
12 CHAIRMAN BALLINGER: This is Ron Ballinger 13 again. The boundary line is about 80,000 pounds. If 14 you look at standard tractor-trailers, on every 15 highway it's usually around, the upper limit on weight 16 is about 80,000 pounds. Above that, you have to do 17 this special permitting.
18 And when they do the special permitting, 19 if there's a curve or something like that, which that 20 route is pretty well analyzed.
21 PARTICIPANT: Significant administrative 22 requirements, yes.
23 CHAIRMAN BALLINGER: And so, you know, it 24 makes a difference.
25 MR. COLES: Again, right, this is a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
80 1 demonstration. And actually what we've done in terms 2 of likely, developing likelihoods is quite 3 sophisticated.
4 All right, Dennis.
5 MR. SHORT: Yeah. This is Steve Short.
6 Just, again, we would emphasize the whole reason for 7 a big part of PRA is there is uncertainty in the data.
8 Right? That's why you do sensitivity analysis, that's 9 why you do uncertainty analysis, to try and get your 10 hands a little bit around where you might be 11 uncertain, and how that might change your risk 12 insights.
13 MR. COLES: Yeah. We'll actually show you 14 an example of the uncertainty analysis that we did on 15 that crash rate.
16 So, am I ready to go forward?
17 CHAIRMAN BALLINGER: Yeah. We better 18 proceed.
19 We're halfway through the slides, and 20 three-quarters of the way through the time.
21 MR. COLES: All right, let's go.
22 CHAIRMAN BALLINGER: Or two-thirds of the 23 way through the time anyway.
24 MR. COLES: Let's proceed.
25 Question?
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81 1 CHAIRMAN BALLINGER: These are the kind of 2 questions you can be asked.
3 MR. ADKINS: Very good questions.
4 MR. COLES: So, Step 6 is to develop the 5 bounding consequence analysis for each BRA.
6 Again, the estimated effective radiation 7 dose pathway, which I'll show in the next slide, is 8 based on Appendix 1 of IAEA SSG-26, with refinements.
9 Like I said, mostly account for the public receptor, 10 because they put the receptor at one meter. We chose 11 to put our worker at one meter and put our public 12 receptor a little further away.
13 To determine the source term, so that's 14 the material that gets released, right, the 15 traditional factor formula commonly used in DOE and 16 NRC, because safety analysis was used for both worker 17 and public according to whatever the accident 18 phenomena was, impact or fire for example, you can see 19 the definitions for the factors at the bottom of the 20 slide there on the right if you want to take a look.
21 For this demonstrations, factors were used 22 -- values, I should say, were used from NRC and DOE 23 handbooks for applicable forms of the radiological 24 material. And where expert judgment was used, values 25 were selected with an object to be bounding to account NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
82 1 for uncertainty.
2 By recognizing that the TRISO fuel 3 particles are much smaller and resistant to failure 4 than standard light-water reactor fuel.
5 So, this slide is about developing 6 consequence for each BRA. And the diagrams there on 7 the right, those represent the radiological dose 8 pathways.
9 The external photon dose is external dose 10 due to released material. But we added contribution 11 from other material from a package with the degraded 12 shield. So, in our collisions we degrade the shield 13 or we take away the external shield.
14 External beta dose is the external direct 15 dose, the skin contamination due to released material.
16 The inhalation dose, that's the QC, is 17 calculated using an source term, which I show on the 18 last slide, and a human uptake rate. Skin 19 contamination QD is calculated from equivalent skin 20 dose. This is from handling debris per the guidance 21 in the SSG-26. Wasn't used towards the risk 22 evaluation guidelines because that's not the way SSG 23 did it. We're going to talk about this later.
24 Because we assumed in our demonstration 25 that anyone handling debris would be trained in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
83 1 radiation safety, and use protective clothing.
2 Neutron dose is not included in the fuel 3 system, and was determined by Q analysis to be a 4 minimal contributor for released material and is, in 5 any event, dominated by the gamma contribution for 6 this demonstration.
7 Other pathways excluded by the Q system 8 are suspension shine, drinking water ingestion. But 9 because they're not significant contributors for 10 irradiated fuel, will likely be mitigated, and would 11 likely be mitigated by response.
12 And then you can see on the bottom there 13 that submersion pathway was excluded because the 14 release is outdoors. So, there would be a high level 15 of dilution on the placement site.
16 MEMBER HALNON: Just a quick question.
17 Are you going to talk about the 18 meteorological conditions that were seen? Because I 19 don't know how you can survey about worse case.
20 MR. COLES: Steve Short, can you help, 21 please?
22 MR. SHORT: Yeah, what we did is we used, 23 we used the Q system assumptions of that, which are 24 set up to be conservative. Because our receptor is so 25 close to the package you cannot use a standard kind of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
84 1 dispersion model. Right?
2 MEMBER HALNON: Right.
3 MR. SHORT: I mean, those are only 4 applicable to things half a kilometer approximately 5 further out.
6 So, we used the Q system, which has built-7 in assumptions about that and are specifically defined 8 to be conservative.
9 MEMBER HALNON: Okay. So, it's like a own 10 source ground level?
11 MR. SHORT: Yep. That's right.
12 MEMBER HALNON: A given one?
13 MR. SHORT: That's right.
14 MEMBER HALNON: Okay.
15 MEMBER MARTIN: As you're looking at the 16 consequences, things change throughout the route with 17 the assumptions. Is there built into your structure 18 a -- I'm about ready to go outside my BRA assumptions, 19 therefore I can't do it, I've got to stop? Something 20 to that effect. Or where there's a -- I mean, a 21 nuclear plant has continuous monitoring of systems.
22 And if we're outside the design basis we take actions 23 immediately to get back within it.
24 It's kind of hard to turn around a 100,000 25 pound truck and say, well --
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85 1 MR. COLES: Okay. Harold, did you want to 2 talk about the safe havens?
3 MR. ADKINS: Sure. And Virgil probably 4 would be the best to speak to that.
5 But there's a couple of things that we 6 took into consideration, one of which is the way that 7 the example, again example, pathway and process, of 8 what the compensatory measures that would be 9 established as part of that in consideration of the 10 weather and the environment, inclement weather impact 11 and things of that nature.
12 And then we've also taken into account 13 that likely, you know, in the case for Pele would be 14 Army managing that asset and relying on safe havens 15 that Virgil could speak to a lot better than I can.
16 But those would be also considered first.
17 MEMBER MARTIN: So, you'd take actions to 18 put it back within, --
19 MR. ADKINS: Yep.
20 MEMBER MARTIN: -- for lack of a better 21 term, design basis?
22 MR. ADKINS: Keep it within its design 23 basis. That's correct.
24 MEMBER MARTIN: Okay. And one last 25 question while I'm talking. I know you addressed NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
86 1 recovery in the report. But I didn't really see a lot 2 of detail on recovery. You assume that they're 3 trained in radiological protections, that your people 4 were covered.
5 If you, you know, are familiar with heavy 6 rescue and the recovery actions, the first responders 7 are probably --
8 MR. ADKINS: Right.
9 MEMBER MARTIN: So, it's going to be there 10 for a while. And then you tend to get very intimate 11 with the load when you're trying to irradiate, get 12 sometimes four, five, six cranes in, you know, prompt 13 and address. In addition to that, you're probably 14 closing down a highway for a long time.
15 Is all that type of consequence to the 16 public taken into consideration, and consequence to 17 the workers from a dose rate perspective? Is that all 18 taken into consideration, some kind of bounding 19 effect?
20 MR. ADKINS: So, this isn't to slough 21 things off at all by any means. But one of the things 22 that we very first we consider as an applicant that 23 comes to the NRC with their SAR, they're going to have 24 to have it on an accident, an accident but as well as 25 an incident recovery plan. Right?
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87 1 MEMBER MARTIN: Right.
2 MR. ADKINS: And it's got to be highly --
3 oh, sorry, Pete -- highly detailed, right, to even 4 obtain the licensing. And that was slightly beyond 5 the scope of what we would consider because we don't 6 have a lot of specific detail that we could integrate 7 into this.
8 And the other thing, too, you run the risk 9 of migrating off a technology neutral application; 10 right? So, and we're still in the process of showing 11 pathway and hardened process. Right?
12 MEMBER MARTIN: Okay. So, it's thought 13 process that's got to be taken into consideration.
14 MR. ADKINS: Exactly.
15 MEMBER MARTIN: But not in this project 16 but certainly in the big picture.
17 MR. ADKINS: Absolutely. Absolutely. And 18 not something that the NRC they would -- and not to 19 speak for the NRC -- they would be looking for that as 20 part of the development of the safety basis and things 21 of that nature as well.
22 MEMBER MARTIN: Okay.
23 MR. ADKINS: Gentlemen, if there's 24 anything that you'd like to add to what I stated, 25 please, or any clarification you'd like to provide.
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88 1 DR. MAHERAS: So, so we have thought 2 somewhat about a recovery plan and what that would 3 look like.
4 As an example, shipments to WIPP have a 5 recovery plan that describes the equipment necessary, 6 the procedures necessary, et cetera.
7 Now, of course, content handled, though, 8 is not the same thing as a micro-reactor. So, it 9 would have to be modified, extended, adapted, et 10 cetera. But you might expect to see the same kind of 11 contents, just not the same kind of details in, in the 12 recovery plan.
13 MEMBER MARTIN: Thank you.
14 MR. COLES: So, if we move to the next 15 slide, this shows Step 7, which is compare the risk 16 results with the evaluation guidelines. So, after 17 both the likelihood and frequency I've developed for 18 the BRA, the results are compared to the guidelines, 19 the right-hand side of the slide. Dose rates, that 20 depending on the accident frequency, the dose limits 21 can be higher or they can be lower.
22 If the accident frequency is between 1E to 23 the minus 5 and 1E to the minus 6 per year, as shown 24 in the red text on the top on the right-hand side, and 25 the dose limits are between 5 and 25 rem for a member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
89 1 of the public, and 25 and 100 for a worker, as shown 2 in the green text. However, if the accident frequency 3 is higher, then the dose limits can be lower; right?
4 So, for example, if the accident frequency 5 is between 1E to the minus 4 and 1E to the minus per 6 unit, shown in the red text close to the bottom, then 7 dose limits are between 1 and 5 rem for a member of 8 the public and 5 and 25 rem for a worker, shown in the 9 green text on the bottom.
10 Next slide. This is Step 8, which is to 11 assess the sensitivity of the PRA modeling assumptions 12 on uncertainties. Sensitivity studies were performed 13 to address the impact of uncertainty and assumptions 14 used in the model. So, lists of model assumptions and 15 bases were documented for the major elements of the 16 PRA. And these were evaluated, first by determining 17 which sources of uncertainty could be screened 18 qualitatively. Plus, they didn't really have a impact 19 on the risk conclusions.
20 Then quantitative sensitivity studies were 21 performed to characterize the impact on the 22 sensitivity using conservative estimates in the 23 inputs, rather than using the baseline assumptions.
24 These results were then compared to the 25 risk evaluation guidelines. I'll show you an example NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
90 1 of a sensitivity study in just a bit.
2 Then, also, a limited parametric 3 uncertainty analysis, typical PRAs, was performed for 4 this demonstration application. Risk results from 5 PRAs typically are reported as mean values when 6 comparing to risk evaluation guidelines per guidance 7 section NRC Reg Guide 1.200, and the 2008 RIDM report.
8 I say limited because data for parametric 9 analysis for transportation PRAs is at this point 10 limited. And I'll show you that, that uncertainty 11 analysis in a little bit.
12 Next slide. This is Step 9, which is to 13 assess defense-in-depth, and Step 10, which is to 14 assess safety margin. As you know, defense-in-depth 15 is a design, an operational philosophy that calls for 16 multiple layers of protection to prevent and mitigate 17 accidents. Multiple layers identified for the 18 demonstration application are shown on the slide.
19 It's one of the multiple physical barriers to prevent 20 release. Passive features, the fact that the PRA 21 shows a risk, administrative controls, and accident 22 recovery plans.
23 Safety margin is a measure of the 24 conservatism that's employed in the design process to 25 ensure a high degree of confidence that it will NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
91 1 perform the needed function, typically to demonstrate 2 adherence to acceptable codes and standards.
3 This slide shows the results for one of 4 the bounding representative accidents of BRA 2, which 5 is a fire only that originates from outside the 6 transport container. There's no crash involved. This 7 could be an engine fire, or a wheel fire, or some 8 other fire that grows to involve the diesel fuel. And 9 then the fire propagates into the transport container.
10 So, just if you could read this result 11 table, the red text in columns two and three show the 12 dose to the worker and public. The blue text there in 13 the fourth column shows the accident frequency.
14 But when you combine these results and 15 compare to the risk evaluations criteria, in the 16 guidelines in the far right-hand column you can see 17 that the risk from this BRA is acceptable. We see 18 there's more details in that slide such as the 19 contribution on the TRISO fuel itself. The 20 contribution from radioactive material in the core 21 structure and the cooling system are also included.
22 The next slide. This slide shows the risk 23 results for the highest case. This is BRA 3. It's a 24 hard impact. It caused the leaks to release 25 radioactive material and degrade shielding. It NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
92 1 includes collision with heavy vehicles and unyielding 2 objects like bridge abutments.
3 Again, just to reverse how this works, if 4 you look at the red text in columns two and three, 5 show the dose to the workers and public. The blue 6 text there in the fourth column shows the accident 7 frequency. If you compare that to the risk evaluation 8 guidelines you see that the risk using our proposed 9 risk evaluation guidelines is unacceptable, both 10 public and the worker.
11 Options to mitigate this risk are 12 discussed a little bit later in the sensitivity study.
13 MEMBER KIRCHNER: This is Walt Kirchner.
14 Clarification: That's for an operating 15 reactor?
16 MR. COLES: No.
17 MEMBER KIRCHNER: End of life fission 18 product inventories?
19 MR. COLES: This is a -- the baseline 20 conditions were they operate, the reactors operate for 21 three years, and it has decayed for 90 days.
22 That's a good question.
23 MR. ADKINS: So, definitely end of life, 24 yes.
25 MEMBER KIRCHNER: Thank you.
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93 1 MR. COLES: So, this slide presents a 2 summary of the demonstration PRA risk results because 3 the risk evaluation guidelines, the blue is the 4 public, the orange is the worker. And you can see, 5 right, we were talking about this earlier, that just 6 the one accident falls above the blue line, and 7 somewhat above the blue line.
8 The bottom of this slide states that 9 certain BRAs are not presented in the graph. These 10 are the criticalities.
11 Two of the BRAs are flooding 12 criticalities. One is from falling into a body of 13 water as a result of a crash. And then the other is 14 fire water inundation.
15 We did calculate the frequencies, actual 16 frequencies for these accidents. They're extremely 17 low.
18 See, on the right-hand side of the chart.
19 And so, we didn't, for this demonstration 20 we didn't, we didn't calculate the consequences.
21 MEMBER BROWN: Excuse me.
22 Why are bodies of water so extremely low?
23 I just think about cars going across the Chesapeake 24 Bay Bridge where there are frequent occurrences of 25 total blockage due to accidents, wrecks, et cetera, et NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
94 1 cetera, during the year. And so and there's a lot of 2 water.
3 MR. COLES: Yeah, yeah.
4 MEMBER BROWN: Wondered if something like 5 this would go off that and include whatever.
6 MR. COLES: It does, yes.
7 MEMBER BROWN: And so that seems to be a 8 little bit.
9 MR. COLES: Well, for this route, 10 remember, that's what we described earlier is we, we 11 actually compute the likelihood of an accident through 12 very complex processes in GIS, what that likelihood 13 is.
14 MEMBER BROWN: Yes. I meant to ask that 15 earlier, what does GIS mean? I missed that. Is that 16 just a compendium of population data?
17 MR. COLES: What's GIS?
18 DR. MAHERAS: So, it's a Geographic 19 Information System.
20 MEMBER BROWN: Oh.
21 DR. MAHERAS: So, so we have two or three 22 that are used on the project. One is to define 23 bridges and bridge heights.
24 A second one is to define the soil types 25 along the routes. And that speaks to the hardness of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
95 1 the target that might be impacted during an accident.
2 And a third provides us the transportation 3 routing that would be used by the package.
4 MEMBER BROWN: I guess the reason I ask it 5 is that roads and other byways there's, could be a lot 6 of room on either side of those bridges that are all 7 very, very restrictive relative to what they can do 8 maneuvering these very tights. So, I would have 9 thought bridges would -- I mean, you have to cross 10 bridges no matter, almost no matter where you go.
11 DR. MAHERAS: Yeah.
12 PARTICIPANT: We crossed the Snake River 13 a number of times. And we did identify every location 14 where we crossed a body of water, not just rivers, 15 streams, but any body of water that could exceed 5 16 meters.
17 DR. MAHERAS: The other thing is in 18 transportation, the first rule --
19 CHAIRMAN BALLINGER: Can you get closer to 20 the microphone?
21 DR. MAHERAS: The first rule is if it 22 doesn't fit, it doesn't ship. And so, shipments that 23 are what we colloquially call high, wide, and heavy --
24 and that's kind of where we are with this reactor --
25 we would have to be permitted by the state.
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96 1 And those would, those permits look at the 2 state of the state of the infrastructure. And they 3 might preclude shipment on routes such as the Bay 4 Tunnel complex.
5 Oftentimes, those kind of areas have 6 HAZMAT restrictions that are invoked by the state.
7 So, we would need to consider that, and likely stay 8 off of those restricted routes.
9 MEMBER BROWN: Okay, thank you.
10 CHAIRMAN BALLINGER: I would presume, by 11 the way, that BRA 3 and 4, 4M, that would invoke 12 compensatory measures.
13 PARTICIPANT: Oh yeah.
14 CHAIRMAN BALLINGER: So, this is a little 15 bit misleading if you don't understand that that's 16 what was happening and move those.
17 MR. ADKINS: Correct. Back into the 18 shade.
19 MR. COLES: And we're going to talk --
20 that's a perfect segue to where we're going on the 21 next slide.
22 MEMBER ROBERTS: Before you move on to 23 that.
24 MR. COLES: I'm sorry.
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97 1 address my question on cliff edge effect.
2 MR. COLES: Yes.
3 MEMBER ROBERTS: That criticality is not 4 showing up on this slide because it's below the 5 probability of frequency threshold. But I'm just 6 wondering why you think it still has a cliff edge 7 effect?
8 MR. ADKINS: I can at least initially 9 speak to that.
10 So, one of the reasons is there's some 11 uncertainty associated with the example that we're 12 using because it originally was slated, and the 13 anticipation is that anything going over the highway 14 would have transportation poisoning to mitigate any 15 kind of criticality event even if it were to breach 16 and take on water.
17 So, in this particular example, since it's 18 not going offsite, it doesn't have transportation 19 poisoned. And we thought that that wouldn't really be 20 a good example, it would drive things off in a 21 district that would be hard to explain and really draw 22 some point of explanation in the pathway and process.
23 MEMBER ROBERTS: In effect, it would have 24 a compensatory measure to ensure the criticality is 25 not going to happen in these scenarios?
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98 1 MR. ADKINS: Yes.
2 MR. SHORT: It might not just be 3 compensatory. It could be the design portion.
4 MR. ADKINS: That's right. Absolutely.
5 Thank you, Steve. Appreciate that.
6 MEMBER BIER: One other point with regard 7 to compensatory measures -- this is coming back to 8 something we discussed a few minutes ago -- is 9 presumably there could also be compensatory measures 10 that preclude shipping when there are storms forecast, 11 to not encounter the worst risk.
12 MR. ADKINS: That's, that's an excellent 13 point, Vicki. And to that end, within the report we 14 make only an example that quite a few compensatory 15 measures that we would offer up, and the reactor 16 vendors are cognizant of those, too. In fact, some of 17 ours were derived directly from the reactor vendors.
18 Thank you.
19 DR. MAHERAS: So, so when you actually 20 ship fuel and waste, that is a very common 21 compensatory measure, you do not ship when the weather 22 is forecast to be bad, or you ship upon an alternative 23 route that is not subject to the bad weather. So, 24 that's a very common compensatory measure.
25 MEMBER REMPE: So, I have not been NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
99 1 watching because I was interested in the topic. But 2 when folks over here on this table speak, you need to 3 say your name for the court recorder. And I know you 4 probably will say it five times before the end of the 5 meeting. But it's important.
6 DR. MAHERAS: Oh. This was Steve Maheras 7 who just spoke. Sorry.
8 MEMBER REMPE: Thank you.
9 MR. ADKINS: Sorry, Joy. Thank you.
10 MR. COLES: So, shall we move to the next 11 slide?
12 MEMBER BROWN: One other question relative 13 to talking about the weather, excuse me, the weather 14 routine.
15 I was just -- this is kind of a practical 16 thing. In this area there's a lot of hurricanes that 17 come floating across Florida and then go up the coast.
18 And they are not even predicted to even touch as far 19 north as we are. And all of a sudden six hours later, 20 whoops, the winds change, now we're getting inundated.
21 You said forecasts. And forecasts can be 22 very, very problematic and deal with certain types of 23 circumstances. Is there any way to take that into 24 consideration or do we just -- is that a one day long, 25 you know, in advance forecast? Because those can be NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
100 1 not correct.
2 DR. MAHERAS: So, we would typically, when 3 you actually ship fuel and waste, look at the near 4 term forecast a day or two, and also longer term 5 forecasts along the route.
6 But hurricanes, yeah, we would like to 7 avoid those, most definitely.
8 And this was Steve Maheras who just spoke.
9 MR. PEOPLES: So, Virgil Peoples, INI.
10 I know we talked about earlier safe 11 havens. I just wanted to clarify for the team.
12 So, safe, safe havens are typically DoD 13 installations that you would move radiological 14 shipments to so you can get them away from the public.
15 Typically, they would be stored on that DoD 16 installation in a safe location where they would have 17 it in the warehouse type of location where it would be 18 safe from anybody around on a particular installation.
19 MR. COLES: Okay. Shall we move to the 20 next slide now?
21 MR. ENGLAND: This is Jeff England from 22 NAC. Can I make a comment?
23 MEMBER REMPE: I'm sorry, are you 24 supporting PNNL? Okay, Gen V --
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101 1 a member of the public?
2 MEMBER REMPE: Yeah. There's a time for 3 public comment at the end of this meeting. I'm the 4 Chairman of ACRS, and that's why I'm answering.
5 MR. WHITE: So, so SCO has a contract with 6 BWXT. BWXT has a contract with NAC for package 7 approval.
8 MEMBER REMPE: If PNNL or later if NRC 9 wants to ask for their assistance, that's fine. But 10 not just to speak up. It's up to the person that's 11 got the floor.
12 Thank you.
13 CHAIRMAN BALLINGER: So, let's continue.
14 MR. COLES: Let's continue. The next 15 slide.
16 This slide is performance sensitivity 17 studies. As I said earlier, selection definition of 18 sensitivity cases were performed based on 19 comprehensive examination of a specific list of 20 assumptions that bases that were used in different 21 parts of the PRA, like the hazards analysis, the 22 likelihood development, and the consequence analysis.
23 Possible compensatory measures listed for 24 the demonstration design to reduce and mitigate risk 25 were also done in this way.
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102 1 The studies we did on this are there.
2 In the next slide I'm going to show you an 3 example of sensitivity studies, how you can use it.
4 So, this slide presents the results for 5 BRA 3. Remember, that's the hard accidents, or that's 6 an accident that exceeds the risk acceptance 7 guidelines. It explores the impact that delay time 8 after reactor shutdown in transport has on risk.
9 So, you see that the red text there in the 10 second and third column, that's associated with the 11 baseline case, so that's a 90-day decay time. And you 12 can see that the guidelines are exceeded in that case 13 for both the worker and the member of the public.
14 If you look in the yellow highlighted 15 numbers in the second and third columns associated 16 with decay time on one or two years, you can see that 17 the risk evaluation guidelines are not exceeded.
18 So, accordingly, this sensitivity results 19 shows that if the delay after shutdown is increased to 20 a year, then the risk for all the highly 21 representative actuals is acceptable.
22 That's one way to use your sensitivity 23 analysis.
24 The next slide I'm going to show you, this 25 slide presents the results of our parametric NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
103 1 uncertainty analysis. In general, like I said, 2 there's, there's not a lot of data to perform 3 parametric uncertainty analysis. As we've heard 4 earlier, there's even variations along the route that 5 you might take into consideration.
6 However, a limited uncertainty analysis 7 was performed on very large truck actual data. And in 8 the limited analysis we increased the actual frequency 9 by 41 percent to match the worst yearly rate of the 10 five states the route covers for the years the data 11 was compiled. And this was an effort to consider the 12 spread of the accident data.
13 The limited analysis did not change the 14 conclusions about the risk to the BRA with this, this 15 one exception. So, this is BRA 4, a medium impact 16 accident. So, this is in the uncertainty analysis if 17 you increase the accident frequency by 41 percent, 18 then you would -- the risk would be unacceptable when 19 you compare it to the risk evaluation guidelines.
20 MEMBER BIER: A minor comment. First, I 21 really like the sensitivity analyses that you did in 22 your study. I thought that was very helpful. You 23 didn't spend a lot of time on that here.
24 I would say that this also I would 25 characterize as a sensitivity analysis, not an NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
104 1 uncertainty analysis.
2 MR. COLES: Sure.
3 MEMBER BIER: It's a different type of 4 sensitivity, but it's basically saying what if this 5 number was higher.
6 MR. COLES: Right. Understood.
7 MEMBER BIER: Minor comment.
8 MR. COLES: So, this slide presents key 9 insights from the demonstration PRA results of 10 sensitivity studies that could be important if this 11 were an actual application versus a demonstration.
12 But one of the major insights was that 13 allowing, like we said, the core to decay up to one 14 year -- excuse me -- after it's been in operation for 15 three years, would result in an acceptable level of 16 risk for all the bounding representative accidents 17 based on the proposed risk evaluation guidelines.
18 The risk conclusions about BRAs are not 19 sensitive to the uncertainty in estimating the source 20 term factors. We moved this quite a bit, for this 21 demonstration anyway.
22 Risk conclusions about BRAs are not 23 sensitive to increasing the accident duration from 30 24 minutes to an hour, for this demonstration anyway.
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105 1 not sensitive to decreasing the distance that the 2 public is to the accident, except for in one case 3 where the guidelines are slightly exceeded.
4 The next slide is the final slide. This 5 is our summary slide 6 So, current NRC regulations provide a 7 feasible regulatory pathway for licensing a first-of-8 kind transportation of a micro-reactor with irradiated 9 fuel.
10 Proposed workable risk evaluation 11 guidelines were developed that are compatible with the 12 Q rules proposed in the 2008 NRC RIDM report.
13 The risk informed PRA crunch can be used 14 to support an application to NRC for approval of a 15 TNPP package containing irradiated fuel.
16 And, number four, the demonstration 17 application of this approach for a hypothetical single 18 shipment per year of a Pele micro-reactor has shown 19 that the proposed risk evaluation guidelines can be 20 met.
21 That is the end of this presentation from 22 PNNL.
23 CHAIRMAN BALLINGER: Thank you, any 24 questions by the members?
25 MEMBER KIRCHNER: Ron, are you going to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
106 1 ask for questions from the members?
2 CHAIRMAN BALLINGER: That's what I just 3 did.
4 MEMBER KIRCHNER: Okay, may I make one?
5 CHAIRMAN BALLINGER: Of course.
6 MEMBER KIRCHNER: I, first, to PNNL people 7 and the staff, this looks like a reasonable, well-8 thought-out framework for evaluating the 9 transportation of micro-reactors. I want to raise the 10 bar a little though, and maybe it crosses over into 11 policy, but it also impacts public safety, which is 12 our concern.
13 It's one thing to do this for national 14 defense and declare national emergencies like a Pele 15 Project. It's another thing to do this for commercial 16 applications. A wide deployment of micro-reactors 17 presents proliferation risks, not only of nuclear 18 material, but proliferation of risk to the public.
19 And there are options, and the most important one is, 20 I think the framework even in the commercial sector 21 could be used for the deployment, that is a fresh core 22 being shipped out to convince the regulatory agency 23 and the public that the risk is acceptable.
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107 1 nuclear fuel cannot be pursued and achieved. So, I 2 just make that as a statement because there's a big 3 difference between national defense and commercial 4 deployment. And there are design options to recover 5 the fuel, spent nuclear fuel.
6 It may not fit the model that some of the 7 vendors would like, but there are means to protect the 8 public. That's it, Ron.
9 CHAIRMAN BALLINGER: Thank you. Charlie?
10 MEMBER BROWN: Yeah, I forgot to ask this 11 question on the first slide, or third slide where you 12 talked about the rating of the micro-reactor would be 13 somewhere between one and five megawatts electrical.
14 And I guess my question had to do with, I just did a 15 little thought process, in my neighborhood all the new 16 houses that are being torn down and built run about 17 72000.
18 And they're all full electrical heat pump, 19 there's no gas on all the new ones, the way they had 20 to be put in. So, that's about 14 houses, and that's 21 -- 14 houses is not a lot, if you go to 5 megawatts, 22 it's 70 houses. So, what determined the megawatt 23 rating, what would their uses be?
24 PARTICIPANT: So, first of all this is a 25 demonstration, Project Pele, I'm going to let our --
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108 1 (Simultaneous speaking.)
2 PARTICIPANT: --- average house using 3 seventy kilowatts.
4 MEMBER BROWN: But if you look at the new 5 house next door to me, it's 5000 compared to mine, 6 which is 3000 square feet. It's two heat pumps in 7 order to keep it running, they can't run the bathrooms 8 without running because it's below grade, they have to 9 pump the sewage out up into the sewer system, and 10 they're fully wireless with the maximum internet they 11 can have, I pick up their wireless in the house.
12 So, they are pumping out, and when it was 13 about 35 degrees out, their heat pumps are running 24 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> a day because you can't get any heat out of 35 15 degrees, that means they were all on resistance 16 heating. So, those are the type of houses -- I'm not 17 in favor of that, but that's just the way they've 18 destroyed the neighborhood.
19 MR. WAKSMAN: Yeah, I would say first of 20 all that as much as I think some people on the 21 internet would like to have a nuclear reactor in their 22 basement, I don't think that's going to be a business 23 case.
24 MEMBER BROWN: No, I was just trying to 25 say what applications business wise was this NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
109 1 envisioned to service, that was my --
2 MR. WAKSMAN: So, for the Department of 3 Defense, the applications that we're primarily looking 4 at are things like missile defense systems, over the 5 horizon radar systems, and --
6 MEMBER BROWN: So, isolated units.
7 MR. WAKSMAN: Yeah, they tend to be in the 8 one to five megawatt range, but we tend to 9 specifically look at micro-reactors, either austere 10 locations, places where it's difficult to get power 11 to, or places where you just really, really have to 12 have power 24 7. Because from a business case, and 13 just from a physics perspective, micro-reactors are 14 going to be significantly more expensive per kilowatt 15 hour1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> than a larger reactor.
16 So, you're not going to do this just to 17 support a larger grid. It's going to be for a really 18 specific application where it's either in a very 19 remote area, or you really cannot afford to lose power 20 no matter what, and it's on some sort of little micro 21 grid. So, I think those would tend to be the 22 application.
23 So, the companies that are looking at 24 using micro-reactors for non-defense applications are 25 looking at things like remote mining, and things like NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
110 1 that. Probably not being deployed around here, where 2 we are right now.
3 MEMBER BROWN: But from a cost standpoint, 4 the only issue with remote mining, I could understand 5 that, but a one to three year full power operation is 6 pretty -- the cost, and then you take that one out and 7 put in a new one, it's like having every two or three 8 years, is that economically -- has that been factored 9 into the thought process?
10 MR. WAKSMAN: So, I would think that 11 seeing as how these reactors, just understanding from 12 our development time, you're not going to want to move 13 these reactors very often if you want to have a 14 business case, just because of the amount of time and 15 effort involved with moving them.
16 MEMBER BROWN: Well, replacing, I mean the 17 mining thing might be there for 25 years, and 18 therefore every 3 years you have to bring in a new 19 micro-reactor. I understand the need, they need 20 power.
21 MR. WAKSMAN: Well, the three year 22 requirement is a requirement that we chose to set for 23 the Pele prototype. It doesn't mean you couldn't 24 design a micro-reactor that had a longer lifetime.
25 MEMBER BROWN: And still ship it.
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111 1 MR. WAKSMAN: Yeah.
2 PARTICIPANT: I would comment too, the 3 Project Pele application has some very stringent 4 performance requirements and envelopes that they're 5 trying to achieve that are slightly different than 6 like an installation energy application or what have 7 you.
8 MR. WAKSMAN: Yeah, our reactor module, 9 without getting into anything proprietary or CUI, 10 there's very little uranium in that core, it's a lot 11 of fueling, and it's because we're looking at a very 12 specific example, needing to move it in a specific 13 time. I would think a commercial micro-reactor would 14 be designed with significantly more uranium in a core, 15 and a longer shipment time.
16 MEMBER BROWN: To get greater utilization 17 time.
18 MR. WAKSMAN: Well, you would allow it to 19 sit there for probably months before you moved it 20 again to allow the dose to come down naturally rather 21 than just trying to shove it in.
22 PARTICIPANT: And operation duration, yes, 23 as well.
24 MEMBER BROWN: Yeah, obviously.
25 MEMBER PETTI: So, Charlie, there are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
112 1 designs out there for micro-reactors that I've seen 2 that are longer lived than this.
3 MEMBER BROWN: I'm just trying to get a 4 calibration.
5 MEMBER PETTI: There's some that are eight 6 to ten years.
7 MR. ADKINS: One of the things I breezed 8 over, and I apologize, is the fact that we selected 9 Project Pele primarily due to the fact that Jeff 10 Waksman sponsored us to do that. But also it's 11 probably one of the first out of the gate that we're 12 going to have to grapple with, and figure out 13 something like it, something fairly close to it, 14 because it is fairly close to completion.
15 Or nearing more than other designs, and so 16 we took that as a primary example to make and work 17 with. So, it was merely a select.
18 MR. WAKSMAN: I mean, we have, really very 19 high confidence at this point of exactly what Pele is 20 going to weigh, exactly what the materials are.
21 Whereas I think a lot of them, micro-reactor vendors 22 out there have not really thought through that much 23 what it's going to look like. So, it's a useful one 24 to model, but again, as I mentioned at the start, we 25 want this to be much broader just as a principle.
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113 1 MEMBER BROWN: Okay, thank you.
2 CHAIRMAN BALLINGER: Okay, we've got to 3 come back to sanity.
4 MEMBER BROWN: Are you saying my question 5 was not --
6 CHAIRMAN BALLINGER: A couple of things --
7 yes.
8 MEMBER SUNSERI: Hey, Ron, I had one more 9 question if you don't mind, if we have time.
10 CHAIRMAN BALLINGER: Fine, okay.
11 MEMBER SUNSERI: Just real quick then.
12 I'm not sure I understand my colleague's comment about 13 risk of commercial versus risk of the military 14 deployment or emergency response. I mean the 15 probability is 50 percent, if I flip it 1 time it's 50 16 percent, if I flip it 1000 times it's 50 percent, and 17 the consequence is the same. So, is it really more 18 risky if you shipped it more? I don't think so.
19 MEMBER KIRCHNER: Well, you just 20 cumulatively, Matt, increase the risk in exposure to 21 the public. Again, I think it's --
22 MEMBER SUNSERI: I think it's the 23 probability, right? I mean all the precautions are 24 still the same. If I ship it one time, I ship it a 25 thousand times.
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114 1 MEMBER BIER: Yeah, but if you drive once 2 in your life your chance of getting in an accident is 3 very small, if you drive every day it's much larger.
4 MEMBER SUNSERI: You're telling me if I 5 submit enough lottery tickets I'll eventually win, I 6 guess, right?
7 MEMBER REMPE: Go for it.
8 CHAIRMAN BALLINGER: So, anyway, we've got 9 a couple of things here, we're behind. We have a hard 10 stop at noon, and that mitigates against us having any 11 break at all, but I would get executed, terminated if 12 I didn't do that. So, we'll have to take a break 13 until 11:00 o'clock, and then we'll pick it up then.
14 Before we do that, we thank you very much for a very 15 complete presentation, thank you.
16 (Whereupon, the above-entitled matter went 17 off the record at 10:51 a.m. and resumed at 11:00 18 a.m.)
19 CHAIRMAN BALLINGER: Okay, we're back in 20 session, and Bernie, you're next, and then others.
21 MR. WHITE: Yeah, I'll lead it off, thank 22 you.
23 CHAIRMAN BALLINGER: Thank you.
24 MR. WHITE: So, I'm Bernie White, senior 25 project manager in the Division of Fuel Management, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
115 1 along with Jonathan Marcano, Brian Wagner, and Tim 2 McCartin, supported by others here, Matt Humberstone 3 for example --
4 CHAIRMAN BALLINGER: You've got to turn on 5 your mic.
6 MR. WHITE: I still need to turn it on, I 7 apologize. So, let me start over, I'm Bernie White, 8 Division of Fuel Management. It will be primarily 9 Jonathan Marcano and I doing the presentation today, 10 we've got others to respond to questions, Brian 11 Wagner, Tim McCartin, Matt Humberstone, and a number 12 of people online to support us.
13 Unfortunately, I think this is going to 14 seem like a little bit of a herky-jerky presentation, 15 because A, we're limited in time, and B, a lot of this 16 stuff already covered in response to questions. So, 17 I'll see what I can do about skipping over the stuff 18 that I've already covered when it comes to questions.
19 So, what are you going to hear from the NRC?
20 First is that we believe the 21 transportation regulatory framework is adequate for 22 covering transportable micro-reactors. There's been 23 a lot said today about Project Pele, and the fact that 24 it is a military application. We didn't look at the 25 framework per se as being for solely a military NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
116 1 application. We looked at it as would it cover Pele, 2 sure, would it cover other reactor vendors if they 3 chose to use it?
4 So, we looked at it from a little bit 5 higher level in that respect. And then we also looked 6 at what in the framework will the NRC expect to see in 7 a package application in more fulsome detail that in 8 it all says it may have neglected. For example I 9 talked about things that, the risk criteria were below 10 the threshold for which you have to determine the 11 dose.
12 We don't believe that, we think we'd want 13 to see dose for every accident no matter what it is, 14 no matter how low the consequence. And they talked a 15 lot about doses that they indicated they neglected.
16 For example, submersion in a cloud dose from the Q 17 system because it's outside. The Q system uses 18 submersion in a cloud, or indoor releases when you're 19 unloading a package.
20 However, you know, it's potential the 21 package could go through a tunnel, one never knows.
22 So, we would expect to see a lot of justification on 23 that, so that's kind of how we looked at it. Between 24 NRC and DOE there's been extensive engagements over 25 the past few years on Project Pele. We'll talk a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
117 1 little bit about our review of the risk informed 2 methodology, and what we saw at a fairly high level in 3 terms of NRC comments.
4 And then next steps in development of 5 potential package application that we expect to get.
6 And Dr. Waksman said that it isn't going to go off 7 site, and so we'd be looking to do a safety review on 8 the package application, probably not approve it for 9 transport for that very reason. So, NRC and DOT co-10 regulate radioactive material, there's a memorandum of 11 understanding between the two agencies which delineate 12 our responsibility, covers a wide variety of topics.
13 Including safety standards, package 14 reviews, inspection, enforcement, accidents and 15 incidents. The MOU delineates each agency's 16 responsibility of transportation. DOT regulates all 17 hazardous material in transportation, of which class 18 seven, or radioactive is just one of the nine hazard 19 classes. Meaning DOT also regulates all modes of 20 transport.
21 Which means that not only DOT has 22 regulations on how hazardous material is packaged, but 23 how that package is carried on a conveyance, in this 24 instance on a truck, a heavy haul truck. They also do 25 rail and air. DOT is the U.S. competent authority for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
118 1 transport, which means that DOT represents the U.S. at 2 the International Atomic Energy Agency under the 3 Transportation Standards Safety Committee, also known 4 as TRANSSC.
5 As the U.S. competent authority, DOT 6 issues certificates of competent authority for NRC 7 approved packages for import, export, and 8 transshipments. Whereas NRC package approvals are for 9 domestic transport only. Also in its role as the 10 competent authority, the DOT issues certificates for 11 packages approved by foreign competent authorities, 12 that's known as revalidations.
13 DOT sets safety standards for a variety of 14 radioactive material, including type A packages that 15 do not include fissile material, low specific 16 activity, and surface contaminated objects. DOT sets 17 standards for external radiation fields around 18 packages, and labeling and marking of packages. DOT 19 also authorizes shipment of NRC approved packages.
20 And so, why am I going over all this?
21 Because how NRC approves a package can impact whether 22 DOT has roles in that approval. If we issue a 23 standard package approval, that's automatically 24 authorized under DOT rules. If somebody were to come 25 in and use this framework and request exemptions, they NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
119 1 would need an NRC approval and a DOT special permit 2 for that shipment.
3 The NRC is responsible for setting safety 4 standards for packages and transportation, and issuing 5 certificates for type B and fissile material packages.
6 I say certificates a lot, I really mean package 7 approvals, certificates is how we do business 99.9 8 percent of the time, but there are other things that 9 we can do, such as letter authorizations, which 10 modifies a certificate in which the package meets Part 11 71.
12 There's also alternative approvals which 13 I'll talk about later, up to and including exemptions.
14 Fissile material packages could have a type A or type 15 B quantity of radioactive material. A type A fissile 16 package is not the same as a type A package, because 17 of the fissile nature of the package. Type A packages 18 are not subject to the accident criteria, whereas 19 fissile material packages are.
20 And that's why we talk about the Q system, 21 and what it does for setting the limits in a type A 22 package, it limits that in the event of an accident no 23 person can receive more than five rem based upon the 24 dose calculations used in the Q system. And we're 25 going to talk about the Q system a bit, but the way we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
120 1 look at it is they use the dose pathways from the Q 2 system, and how some of those calculations were done, 3 and PNNL touched on that earlier.
4 So, going back to the DOT package 5 standards noting that a type -- sorry. So, in 6 addition as requested by the Department of 7 Transportation, the NRC performs package reviews, and 8 recommends whether DOT should revalidate foreign 9 approved packages. So, we kind of act as a contractor 10 to DOT.
11 They send us an application that has been 12 approved by a foreign competent authority for which 13 one wants import, export, or transshipment through the 14 United States, and we will recommend whether DOT 15 should issue a certificate for that. So, I won't 16 belabor the point here, we've talked a lot about 17 normal conditions of transport, hypothetical accident 18 conditions.
19 These are the tests that are done on 20 packages that NRC approved. Normal conditions of 21 transport are intended to what a package might 22 experience during transport. Hypothetic lacks in 23 conditions on the other hand are not designed to be 24 any specific accident, but designed such that if a 25 package can meet the dose rate and containment NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
121 1 criteria, which I'll show in the next slide, 2 criticality safety, a package that is in an actual 3 accident would protect the public health and safety.
4 Package performance criteria. So, I 5 talked a little bit about a lot of these earlier, 6 these are the criteria that we expect packages to meet 7 during normal package approval, we do a normal package 8 approval. There's criticality safety, a single 9 package, an array of packages, think array of 10 packages, Pele really, but we have a lot of packages, 11 fuel assembly packages, uranium hexafluoride, things 12 like that that are shipped in arrays.
13 They might be small, they could be large, 14 there used to be a significant number of pellet and 15 powder shipments that were 55 gallon drums shipped in 16 quite large arrays. So, we do array analyses for 17 that. There's three single package analyses for 18 criticality safety, one is a non-mechanistically 19 flooded package. So, as the package is prepared for 20 shipment, when you put water in the maximum reactive 21 credible extent, and evaluate the K effective.
22 Along with after normal conditions of 23 transport and hypothetical accident conditions. And 24 then for array of packages, an applicant has to look 25 at 2N array, or normal conditions of transport, 5N NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
122 1 array for hypothetical accident conditions where N is 2 the number that it chooses, the applicant chooses to 3 show that it's subcritical.
4 So, if the applicant chooses five, for 5 example, they'd have to look at 25 packages for normal 6 conditions transport, 10 packages for hypothetical 7 accident conditions. And that value of N is used to 8 calculate the maximum amount of passages that can be 9 loaded onto a conveyance. So, that's why we go with 10 that standard number, it's a good barrier.
11 Spent fuel packages may have a criticality 12 safety index of 100, which means that you can only 13 ship one package on a conveyance. For dose rates, 14 there are different dose rates depending upon the 15 package. All packages have to meet the normal 16 conditions dose rate in 71.47, or the DOT version in 17 49 CFR 173.441. And then if you have a type B package 18 there are additional dose rates you have to meet.
19 For normal conditions of transport, there 20 must be no significant increase in the dose rate after 21 those tests. Typically IEA guidance has about a 20 22 percent increase in dose rate being significant. For 23 after hypothetical accident conditions the dose rate 24 is one R per hour around a package. That's been found 25 by the international community to be protective of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
123 1 public health and safety.
2 Containment criteria, I talked a little 3 bit about those earlier, ten to the minus six A2, and 4 A2 per week for normal and accident conditions 5 respectively. We've already talked a lot about what 6 Project Pele is, I will skip that in the interest of 7 time. I think we've talked a little bit about --
8 sorry, I missed a slide.
9 So, levels of regulatory engagement. I 10 won't cover a lot here, but I will say that we've been 11 following Pele in my division, the Division of Fuel 12 Management for a couple of years now, we're acting as 13 a regulator for package approval. The Office of 14 Nuclear Reactor Regulation has a role in Project Pele, 15 and it is to provide DOD and DOE with accurate current 16 information on the prototype such as reactor design, 17 siting, construction, fuel selection and operations, 18 things it oversees in the reactor side of the house.
19 Skip most of that because we've already 20 covered it. So, why a risk informed methodology, in 21 the event that the Pele package or a transportable 22 micro-reactor can't meet any of those criteria I 23 discussed after a hypothetical accident conditions.
24 The risk informed methodology is not applicable to 25 normal conditions of transport as defined by SCO and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
124 1 PNNL.
2 And we would not expect to see that as 3 well. I talked a little bit about alternate test 4 criteria and exemptions earlier, so I will skip that 5 in the interest of time. And I'll turn it over to 6 Jonathan to talk about the risk methodology.
7 MR. MARCANO: Thanks, Bernie. Good 8 morning, can you hear me? It's Jonathan Marcano, NRC, 9 NMSS. So, we will now transition into the technical 10 content, as well as the staff review of the 11 methodology. As Bernie described on the previous 12 slide why the methodology serves as a basis for the 13 regulatory pathway through exemptions, the next 14 question is what are some of the technical challenges 15 in pursuing this pathway, we have seen some questions 16 around that.
17 So, one of those challenges is that the 18 risk assessment for the transportable micro-reactor is 19 a first of the kind, and as it might be -- it has been 20 pointed out there are some reports assessing the risk 21 associated with spent nuclear fuel transportation for 22 generic, and NRC 35 casks. Those have been leveraged 23 by PNNL and the staff, but this is the first time a 24 methodology is developed to determine accidents and 25 potential consequences to members of the public and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
125 1 workers for a transportable micro-reactor.
2 So, we'll be covering more details in the 3 next few slides. So, consistent with the NRC's risk 4 informed and performance based concepts, the proposed 5 methodology serves as a systematic method for 6 addressing the risk triplet. As it relates to the 7 performance of the system, the understand likely 8 outcomes, sensitivities, areas of importance, system 9 interactions, and areas of uncertainty.
10 Therefore, the staff review of the 11 methodology focuses on that systematic process to 12 evaluate the risk associated with the transportation 13 of the micro-reactor, identify important scenarios 14 that drive the risk, inform the design of components, 15 and identify the need for compensatory measures. The 16 staff has previous experience, as it has been pointed 17 out, applying risk informed approaches to informed 18 exemptions from regulatory requirements for a package 19 with similar challenges.
20 During its approval, the Trojan Reactor 21 Vessel package in October of 1998, as part of that 22 approval the NRC granted two exemptions to deviate 23 from performing the drop in the most damaging 24 orientation of the package, as the probability of 25 accidents damaging the package beyond that evaluated NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
126 1 was less than one in a million.
2 Other additional considerations by the NRC 3 staff as part of this review of the methodology for 4 exemptions includes the limited number of shipments.
5 In this case, one single shipment per year, two total 6 over several years, and that the package is expected 7 to meet normal conditions of transport, or NCT as it 8 had been mentioned by Bernie, and some hypothetical 9 accident conditions or criterions.
10 Next slide, Bernie. So, the purpose of 11 this slide is to introduce the major elements of the 12 methodology as proposed by PNNL. We will be covering 13 the risk evaluation guidelines in the next slide, and 14 some of the elements presented here will also be 15 covered during the next slide. As it has been 16 presented, the first step in the methodology discusses 17 the development of proposed risk evaluation guidelines 18 in the form of frequency consequence targets to 19 evaluate the risk assessment results from the 20 transportation package.
21 The methodology then presents key elements 22 of the probabilistic risk assessment method, PRA for 23 short, such as those listed in this slide, and you 24 have seen a presentation by PNNL. Therefore, the NRC 25 review focused on ensuring that the methodology NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
127 1 described in enough details how the risk informed 2 framework will be used to get an understanding on how 3 key elements such as sensitivity analysis will be 4 treated, and how we will consider approaches for 5 defense in depth and safety margins. Next slide.
6 Yes?
7 MEMBER REMPE: I don't know if you were 8 around earlier when I brought up about the 9 identification of safety functions, and again, Bernie 10 has said you're looking at this for a higher level.
11 I look at your evaluation, it just says hey, they 12 identified the safety functions in 5.2, and if I look 13 at 5.2, and what they presented today, again, they 14 talked about the two higher levels, shielding, and 15 contain radiation, and a couple of things that might 16 challenge that, criticality, or passive heat removal.
17 But it seems to me since this is going to 18 be an evaluation that could be used for other concepts 19 and designs, it would behoove you to elaborate a bit 20 more that maybe some other critical safety functions 21 that could challenge those primary two safety 22 functions would be a good modification to your draft 23 evaluation. Is that something that you might agree 24 to?
25 MR. WHITE: Sure.
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128 1 MEMBER REMPE: You might.
2 MR. WHITE: Yeah, so let me explain. So, 3 we looked at the methodology as being, I would call it 4 a precursor to a package application, okay? The 5 package application would look at all the things, or 6 most of the things you identified earlier, for example 7 chemical interactions is one of the things. We look 8 at that as a matter of routine practice for our 9 package applications.
10 We didn't think it needed to be put in 11 here because that's what we always look at for every 12 single package. What is different about how we would 13 evaluate a transportable micro-reactor from a standard 14 package is how we looked at the methodology.
15 MEMBER REMPE: But considering there's a 16 lot of concepts, a lot of new design developers, I 17 think a couple sentences, you can do it in one, would 18 be prudent. Because people will pick up this document 19 and use it in the future. And it's something that --
20 again, you look at the regulatory, the reactor side in 21 our regulations, the critical safety functions vary, 22 and I just would like to start seeing more 23 consistency. Thank you.
24 MR. McCARTIN: Bernie, could I just add 25 one thing? You do raise a very good point, and what NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
129 1 we're trying to do in the approval is to be very clear 2 that we're approving the methodology, the approach, we 3 see the steps, but the details, and that's -- there's 4 this fine line, what's detail, and what's part of the 5 methodology?
6 I think being clear that there's things 7 that this is a first of a kind, what kind of 8 challenges you might see, we are going to look for a 9 justification of the kinds of things you've included, 10 and why, kinds of things you've excluded, and why.
11 And so I think we will take what you said to heart, 12 and look at how we've written this to make sure we 13 clearly identify.
14 Because there is this, we don't want to 15 leave on this understanding that gee, we thought you 16 approved, for example, there's a lot of discussion 17 about the frequency for accidents. You've got to --
18 whatever you come up with has to be supportable, 19 defendable, and give us the information. And the 20 demonstration used a lot of different things to help 21 us see how the approach would be used.
22 But what's approach, and what's 23 demonstration? There are some things that are 24 approached for us, and clear, but maybe it isn't as 25 clear to others. However we approve it, we want to be NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
130 1 very clear as to what's needed in the supporting 2 information, and that's what I take from your comment.
3 MEMBER REMPE: Thank you.
4 CHAIRMAN BALLINGER: I may have missed it, 5 but did you supply your name for the court reporter?
6 MR. McCARTIN: I'm sorry, Tim McCartin, 7 NRC staff, I apologize.
8 CHAIRMAN BALLINGER: Thank you.
9 MR. MARCANO: We can move to the next 10 slide. So, on the previous slides, Bernie described 11 some of the prescriptive requirements for testing, and 12 the specified acceptance criteria within 10 CFR Part 13 71. The regulation as written ensures safety by 14 requiring conservative estimates on the damage to a 15 cask, ensuring robust performance in an accident, and 16 requiring conservative numbers on the radiation 17 emitted from the casks during transportation.
18 Therefore Part 71 does not include 19 quantitative targets, IE likelihood, dose thresholds 20 for approval of transportation packages. With the 21 assumption that the package may not meet all the 22 deterministic requirements and acceptance criteria 23 after a hypothetical accident, a HAC, the methodology 24 proposed a set of risk evaluation guidelines for use 25 in determining safety or the risk acceptability from NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
131 1 shipment.
2 The guidance considered the frequency and 3 consequences by defining pairs of likelihood dose 4 thresholds from the potential exposure to radioactive 5 materials during postulated severe transportation 6 accidents. The likelihood is defined as accident 7 frequency, and we've had many discussions about that, 8 and the consequences are defined as total effective 9 dose equivalent, or TEDE.
10 The pairs of likelihood dose thresholds 11 are defined for a worker involved in the 12 transportation of the package, and a member of the 13 public located close to or involved in the accident.
14 The member of the public is defined to be the 15 maximally exposed off site individual.
16 MEMBER ROBERTS: I asked a question 17 earlier to PNNL about the qualitative safety goals, 18 and the one of societal risk, and the implication in 19 transportation when you're shipping this package 20 through or around Denver, you've got a risk profile 21 than you would in the middle of the desert. Some of 22 your previous work had person rem, or person sievert 23 metrics that were in there that were used to try to 24 judge.
25 I didn't see any of that in the PNNL NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
132 1 report, or in your draft safety evaluation. If you 2 could comment on the societal risk, and how that's 3 being applied through the whole.
4 MR. WAGNER: Yeah, we talked about --
5 sorry, this is Brian Wagner, NRC. We've talked about 6 that a little bit internally. I think to some extent 7 that's covered in environmental reviews, although 8 that's not my area of expertise. To a larger degree, 9 we expect that would be covered by the way the dose 10 calculations are done. They're limiting the dose to 11 the maximally exposed off site individual.
12 And by doing so you're going to 13 necessarily to some degree limit the societal risk.
14 That's not always fully true in some circumstance when 15 you have larger source terms, or taking protective 16 actions which might limit the dose your maximally 17 exposed individuals are getting more than they're 18 limiting the silo dose.
19 But in this case, you would kind of expect 20 that the overall inventory and source term are 21 relatively modest compared to a large reactor for 22 example. Such that the people right around the 23 accident are really the ones that are going to be most 24 exposed, and that people at any kind of significant 25 distance are probably not going to be getting a whole NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
133 1 lot of dose. And that's what we've seen in past 2 transportation PRAs.
3 MEMBER ROBERTS: The 2008 RIDM document, 4 and I'm not sure that the part of this is necessarily 5 always true, if you had your highest risk of flying 6 accident for example, in the middle of a city, then 7 maybe that would be a different story than if the same 8 -- the integrated risk had that -- integrated 9 probability had that flying potential in the middle of 10 nowhere.
11 Just something to look at. At the very 12 least it seems like there are going to be some 13 discussions of this qualitative goal, and how that's 14 tested in the context of transportation. But that is 15 different than a reactor site where you've got other 16 environmental reviews, and other regulations to limit 17 the affected population.
18 Whereas here you're kind of putting that 19 protection in a package, and in the analysis you use, 20 and not so much in the affected population. But I see 21 what you're saying, and it may very well be that when 22 you look at the individual risk metrics it gets you 23 satisfactory coverage to societal risk. Or it may 24 drive us to desire some additional margin somewhere.
25 Thank you.
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134 1 MEMBER BIER: I would also just 2 reemphasize my point from earlier this morning, that 3 I'm not sure it makes sense to look at the pairs of 4 likelihood and dose individually rather than 5 integrating them over the entire trip or whatever, the 6 entire range of possible scenarios, and taking an 7 overall perspective. That's just me.
8 MR. MARCANO: So, we've talked about the 9 references used in the development of the evaluation 10 guidelines, and how the methodology aims to tie those 11 proposed guidelines to the QHGs defined in the RIDM 12 report. So, the staff review focused on ensuring the 13 risk targets are consistent with NRC risk informed 14 approaches to be used as objective means of comparing 15 the likelihood and consequences of the scenario.
16 Therefore the staff review was aimed at 17 confirming that the methodology proposed a 18 conservative approach to calculating risk targets, to 19 demonstrate the public health and safety is protected 20 during transportation of the micro-reactor. Therefore 21 the staff took into consideration the totality of all 22 the references used for the delineation of the 23 guidelines, such as DOE guidance, and guidance in 24 NUREG-1520 developed for fuel cycle facilities, as 25 well as the IAEA Q system.
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135 1 Additionally, based on our review, the 2 staff agrees that the approach is similar to risk 3 informed approaches previously endorsed by the NRC to 4 support the licensing of advanced reactors in Reg 5 Guide 1.233, which endorses the NEI 18-04. Next 6 slide. And PNNL covered this, this is mostly for 7 illustrative purposes to show the frequency 8 consequence plot for the members of the public.
9 The next slide will cover the frequency 10 consequence plot for the worker, and we don't plan to 11 go through each of the anchor points. We do have a 12 slide in the reference, slide 28, that includes the 13 anchor points that were presented by PNNL. I do want 14 to note that the proposed targets in the methodology 15 are slightly more conservative than those previously 16 endorsed by the NRC in Reg Guide 1.233.
17 We can move to the next slide. So, now 18 we're moving from the risk evaluation guidelines into 19 the key elements of the PRA methodology. As part of 20 the first elements within the PRA, the methodology 21 evaluates hazardous conditions that may exist during 22 transport to formulate realistic scenarios. It 23 consists of three elements. Characterization of the 24 primary hazard, the radiological material inventory.
25 Identification of the micro-reactor safety NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
136 1 function designed to prevent or mitigate accident 2 scenarios associated with the radiological material 3 inventory. Identification of accident scenarios and 4 their likelihood. The results are compared to NUREG-5 2125, which is a spent fuel transportation risk 6 assessment to review the comprehensiveness of the 7 process.
8 The methodology later identifies 9 representative and bounding accidents that may result 10 in the release of radioactive material to the 11 environment, or indirect radiation exposure to workers 12 or the public. A total of 32 representative events 13 were identified. The bounding representative 14 accidents, which were grouping to 32 representative 15 events, which were then grouped into 13 accident 16 scenarios referred to as bounding representative 17 accidents for detailed analysis.
18 So, the staff reviewed these areas, and 19 agreed that the methodology appears to provide a 20 systematic approach to identify accident sequences 21 that drive the risk.
22 MEMBER REMPE: I'm less certain on this 23 one about my comments about it doesn't make sense to 24 multiply the fraction of the path by the whole 25 distance to estimate the frequency. But actually what NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
137 1 Member Bier said is suddenly driving home, that if you 2 did what she's suggesting, and consider the frequency, 3 and the consequences every point along the path, that 4 you'd have a more accurate representation.
5 But what they've done, and again, you're 6 looking to approve the methodology, not the specific 7 numbers, and that I would call as part of the 8 methodology, where they've divided this, and they've 9 made that frequency lower because it's only a small 10 fraction of the whole path. Is that what you guys 11 always do in these types of evaluations, or are you 12 giving them a very low frequency benefit? I'm not 13 sure if I'm communicating what I'm trying to say very 14 well.
15 MR. WHITE: So, being the non-PRA person, 16 I'll start by saying we don't typically do these 17 things in analysis. Because we don't have to, because 18 the package meets Part 71, when you meet Part 71, you 19 meet the dose containment criteria, you're protecting 20 public health and safety, so we don't typically look 21 at that.
22 We would look at, along the route, the 23 possibility of accidents, and calculate collective 24 dose to people along the accident. But that's really 25 to show that the regulations in Part 71 are protective NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
138 1 of the public health and safety, and by meeting the 2 regulations, the package is protective of the public 3 health and safety.
4 MEMBER REMPE: So, I guess look carefully, 5 at 182, look at that frequency and how they've 6 estimated it. Because to me it doesn't sound right.
7 If you've done what Vicki is suggesting, yeah, it 8 would probably not do it, but it just doesn't seem 9 right.
10 MR. WHITE: So, let me start by saying 11 sorry, Bernie White, NRC staff. And this is where I 12 turn to my colleagues to see if they have any comments 13 on that, being the non-PRA person.
14 MR. McCARTIN: Yes, Tim McCartin. I think 15 I agree completely. We need to go back, and we know 16 what was done, but what you're talking to is a very 17 important aspect of what -- and we want to be very 18 careful in explaining what we're approving and why.
19 And people can look at different things, and well, 20 that's part of the methodology versus part of the 21 demonstration.
22 And the particular point you're talking to 23 is there's a fine line there, I think. But I think I 24 do, right now, I would agree with you, that actually 25 is part of the methodology, and we need to look at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
139 1 that, and articulate. Right now I'm not going to try 2 to come up with it, we want to --
3 MEMBER REMPE: That's fine, that's the 4 answer that I wanted to hear, just look at it further, 5 because I don't know the answer.
6 MR. McCARTIN: We want to think a little 7 bit more about that, and we want to be clear in 8 whatever we go forward with.
9 MEMBER REMPE: Thank you.
10 MEMBER HALNON: I have one other question, 11 being a non-PRA, very deterministic person. Is it 12 assumed that when you get an accident it becomes non-13 transportable at that point and just stays stationary?
14 MR. McCARTIN: No, the easy answer is no, 15 not necessarily. It really depends upon the package, 16 and the type of accident, and the damage to the 17 package, that's really what it comes down to. For 18 example, and I'm probably going to get the year wrong, 19 but I want to say it was in 2021, there was a shipment 20 of uranium hexafluoride came from France to the port 21 of Baltimore, offloaded onto a truck, was driven down 22 95 going to Westinghouse.
23 Truck had an accident, car cut in front of 24 it, it hit the car in front of it, the uranium 25 hexafluoride over packs are shipped on a flat rack.
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140 1 So, it basically looked like a SeaLand container 2 without the walls. So, it's got kind of a back, and 3 then structure, and the racks are strapped onto that, 4 there's four of them.
5 That flat rack came off the truck, two of 6 the packages came off the flat rack. So, what was 7 done in that instance is they got a crane out there, 8 they took the two packages, they put them back on --
9 they got a new flat rack, they put all the packages on 10 a new flat rack, shipped it to a local -- I'm not 11 remembering the term, but it's a place, not a truck 12 stop but a place a truck would go to evaluate it.
13 They looked at the packages, determined 14 whether or not they were transportation worthy, and 15 determined they were based upon the damage to the 16 package, and then they were shipped along the way.
17 So, the answer is not necessarily.
18 MEMBER HALNON: Okay, so this methodology, 19 we talked about the recovery earlier, that's more to 20 come, because I see that's the problem. I mean, 21 transporting a great cask that doesn't have any 22 accidents is perfect, it's afterwards that I'm worried 23 about.
24 MR. McCARTIN: Right, and recovery is 25 probably -- not probably, it is mode dependent, it is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
141 1 reactor dependent. We didn't look at that in great 2 detail here because of that very fact that it could be 3 reactor and accident dependent.
4 MEMBER HALNON: Okay, and I understand 5 that, that to me is the safety issue, not transporting 6 a perfectly good cask on a sunny road. Or you can ask 7 folks in my home state, East Palestine are still 8 dealing with the emotional aspects of having a train 9 go through. So, anyway, to me, if I ask you any 10 questions about recovery just say hey, we talked about 11 that already, we got it.
12 MEMBER BIER: But that's a really 13 interesting point, Greg, because when you said does it 14 become non-transportable, and the answer is not 15 necessarily, almost no matter how bad the damage is, 16 you're not going to leave it in the creek bed or 17 whatever, you're going to transport it somewhere in a 18 much worse condition than you would hope to transport 19 it. So, might be worth having a follow on analysis 20 that looks at that.
21 MR. WAGNER: Brian Wagner, NRC, I'll just 22 note that recovery operations are typically not 23 covered in PRA, we consider the consequences in the 24 relatively immediate aftermath. The entire operation 25 Bernie just described of how you're recovering, or NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
142 1 what you're doing after, that's really nothing that 2 is, I think ever covered in PRAs, for better or worse.
3 MEMBER HALNON: I would just note that 4 when I was an operator, I did very simulation of 5 normal operation. It was always recovery operations 6 what I was trained on. And that was where we focused, 7 because that was the highest risk to the public. So, 8 to me, the highest risk to the public is the recovery 9 and operation, just wanted to say that.
10 MR. WHITE: So, now we'll walk through the 11 accident sequence analysis as we looked at it. The 12 consequence analysis has several steps, one of which 13 includes accident sequence analysis. For a spent fuel 14 transportation package with its passive features, this 15 typically includes forming an engineering evaluation 16 of the damage to the package, which would include the 17 package as it's shipped, which would include looking 18 at chemical reactions and things like that, that may 19 degrade the package.
20 While the methodologies and approach to 21 determine risk for transport of a transportable micro-22 reactor, the actual analysis in this methodology don't 23 represent damage to the package. It was based on 24 engineering judgment by PNNL, and so we didn't review 25 that specific detail. I'm trying to skip the things NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
143 1 I've already covered in some of my questions, so bear 2 with me just a little bit.
3 NRC would expect that the package 4 application would either provide an engineering 5 assessment of the reactor for the accidents that it's 6 evaluated, and include damage to the package and 7 potential releases along the route with appropriate 8 justification. The package applicants should evaluate 9 the radionuclide inventory that it expects to have at 10 the time of shipment.
11 In the methodology, PNNL will assume that 12 the reactor was operated to its full life expectancy, 13 and then determine radionuclide quantities for various 14 cooling times from right at shut down to up to three 15 years. And as you saw from PNNL, they did sensitivity 16 analysis on some of those to determine that it can 17 have a large effect. It's possible that reactors 18 could be operated for a short period of time and then 19 shipped, or a long period of time and shipped.
20 So, we would expect the application to 21 evaluate whatever it expects to be the radionuclide 22 inventory in the package at the time of shipment.
23 While PNNL provided a two phase screening of the 24 radionuclides, one in total activity, and the other 25 one in A2 value, while the NRC has accepted screening NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
144 1 based on A2, NRC's acceptance has been based on the 2 package releasing no more than an A2 in an accident 3 after hypothetical accident conditions.
4 If the package were to release more than 5 an A2, NRC would expect that one of the sensitivity 6 analyses that would be performed would be on the 7 neglected radioisotopes. Kind of the A2 screening is 8 based on a limited quantity release in A2. If you 9 release a million curies for example, that A2 10 screening may not be appropriate.
11 PNNL developed primary release, meaning 12 radio nuclides that came out of the core, migrated to 13 other areas, and were released in the reactor module.
14 They neglected secondary releases such as activated 15 components of the reactor itself. PNNL deemed those 16 to be of small, low significance. NRC would expect 17 the applicant to either include them or justify the 18 fact that they are a low significance.
19 DR. SCHULTZ: Bernie, this is Steve 20 Schultz. Just focusing on the material release, both 21 going and coming back from its operation. One of the 22 things that was suggested both in the PNNL report, and 23 also in your evaluation was mechanical testing 24 associated with the TRISO fuel, that additional 25 information related to mechanical impact testing would NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
145 1 be useful. The one bounding representative accident 2 that is outside the bounds is high impact.
3 So, is this testing going to be 4 recommended, is it planned, where does that stand at 5 this point?
6 MR. WHITE: So, I don't want to speak for 7 SCO, but they had to develop a testing program for the 8 TRISO fuel, which includes mechanical impacts. We've 9 seen a draft plan of that.
10 DR. SCHULTZ: Do you know what the 11 schedule for that is?
12 MR. WHITE: I do not.
13 DR. SCHULTZ: We can find out, but that's 14 part of your evaluation?
15 MR. WHITE: Right, and in looking at a lot 16 of the work that's been done on TRISO, most of it is 17 in reactor testing at temperature. For us, 18 temperatures in a fire accident aren't that high.
19 We'd be looking more at what's the mechanical impact 20 in an accident.
21 MR. WAKSMAN: I'm not going to be able to 22 answer your question precisely because some of the 23 testing that we're doing is classified, and some of it 24 isn't, and I don't remember exactly the boundaries, so 25 I don't want to get myself in trouble. But I can tell NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
146 1 you that we are planning to do some physical testing 2 of TRISO over the next couple of years.
3 And we've been coordinating that with the 4 NRC team, so the NRC folks are tracking. We've had at 5 least one classified meeting with them to walk them 6 through what we are planning to do. And part of the 7 input we were taking is there particular data that 8 will be helpful to the NRC, that maybe we could 9 collect, or might not collect, or just to try to 10 coordinate as well as we could.
11 DR. SCHULTZ: That's the information I 12 wanted on the record, so that's fine, thank you.
13 MR. WHITE: A lot of discussions about the 14 dose pathways, I'll skip most of this in lieu of time, 15 since we're at about 11:44 already. But one thing I 16 will say is that there are a number of dose pathways 17 that were neglected by PNNL, we would expect that the 18 applicant would justify those, especially if it's a 19 large release. Some of those may not be insignificant 20 dose pathways.
21 PNNL also indicated the neutron dose they 22 expect to be insignificant. NRC has found in some of 23 its package reviews, especially after hypothetical 24 accident conditions, that where you have a small 25 amount of low Z material, neutron dose can be not NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
147 1 appreciable like the same as a gamma dose, but not 2 neglectable either. And so, we would expect an 3 applicant to evaluate neutron dose from the accident.
4 These are dose pathways from the Q system, 5 I won't go over any of that. So, if you're estimating 6 the consequences, the methodology provides a summary 7 of the radiological risk for each of the bounding 8 accidents, and compares the likelihood in dose to the 9 risk evaluation guidelines. The methodology then 10 describes a process to evaluate sensitivity and 11 sources of uncertainty.
12 We would expect a much more fulsome 13 discussion of sensitivity on certainty analysis, and 14 defense in depth in the package application, which 15 would be reactor dependent. Staff review agrees that 16 the methodology provides an adequate process to 17 identify, characterize, and understanding the impacts 18 of modeling assumptions, model inputs, and key sources 19 of uncertainty.
20 Additionally, the methodology articulates 21 the defense in depth approach for Project Pele based 22 on the multiple layers to prevent release of 23 radiation, passive nature of the design, and 24 compensatory measures taken to reduce risk to worker 25 and public. For example, the one point that PNNL NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
148 1 showed that was above the limits, if you sit, decay it 2 a couple of years, you're below the limits.
3 Other things as not shipping in bad 4 weather, looking at weather forecast days, weeks out.
5 Ensuring that if you're going to ship, it's not in 6 high traffic volumes, likely to have more accidents, 7 and things like that. So, there's a number of 8 compensatory measures that can be taken to minimize 9 the probability of an accident.
10 And moving along, I'll just hit the next 11 steps. So, where are we for the next steps? We're 12 scheduled to have an ACRS full Committee on December 13 6th, we have an information commission paper that is 14 in the process of going through concurrence that we 15 hope to issue by the end of January. Attached to that 16 would be the NRC management reviewed draft methodology 17 evaluation, and I know it was mentioned earlier, we 18 don't call it a safety evaluation.
19 And we don't do that because we don't 20 compare it to anything in NRC regulations for 21 acceptance criteria, it's a higher level approval.
22 That would be an attachment to that information 23 commission paper, and then if all goes as planned, we 24 would look to endorse the framework in the February 25 time frame after issuance of that commission paper.
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149 1 NAC has indicated that they'd like to have 2 the methodology approved by the end of January, or 3 thereabouts, because it plans on starting its PRA at 4 about that time. We expect to have pre-application 5 engagement with NAC, so I said earlier that SCO 6 contract with BWXT to design, build, and operate the 7 reactor, BWXT contracted with NRC International to 8 develop a package application for us to review.
9 We expect pre-application engagement with 10 them in the first quarter of 2024, and NAC has 11 indicated that we should expect an application for 12 this by the end of calendar year '24. A few 13 references, and there ends our quick overview.
14 CHAIRMAN BALLINGER: Okay, I guess we 15 should get public comments first. So, if there are 16 members of the public that would like to make a 17 comment, please state your name, and if necessary, 18 your organization, and make your comment. Hearing 19 none, thank you very much. We need to have a little 20 bit more clarity. Again, we had scheduled a full 21 Committee meeting as a placeholder, not knowing what 22 was going to happen to go forward.
23 That would only be the case if we were to 24 write a letter, in which case, as it now stands, and 25 it might change in 30 seconds, we were not planning on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
150 1 writing a letter, and we got information that said you 2 don't necessarily need, want a letter. But I'm just 3 one person. So, now we need to have some discussion 4 around the table, and amongst our members online on 5 what their opinions are, what we should do with 6 respect to a path forward.
7 So, I'm not sure where to start, how about 8 Tom? How about who?
9 MEMBER REMPE: The staff has indicated 10 they're receptive to some suggestions for change, and 11 what would be your time line for implementing those 12 changes, can you do something by the first week of 13 December?
14 MR. WHITE: That's a loaded question. Can 15 we do something, absolutely. Get it reviewed by 16 management and out the door in a publicly available 17 form, not clear about that to be honest with you, 18 given the fact that next week is Thanksgiving, most 19 are planning on taking off a good bit for 20 Thanksgiving.
21 CHAIRMAN BALLINGER: I'd add that there 22 are other options. One of them being that we would 23 write up a summary, if you will, of this meeting, that 24 would include suggestions, if you will, not in a 25 formal letter, that would be incorporated and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
151 1 discussed in our policy and procedures, it would 2 become part of the record, which you would have access 3 to. So, that's another venue which is probably 4 quicker.
5 MR. WHITE: Okay.
6 MEMBER REMPE: So, one thing that could 7 occur is you could still present at the full Committee 8 meeting with what your planned changes are, and then 9 again, it's at least on the transcript in the record, 10 and would that help with your time frames rather than 11 having to have something documented, that with all due 12 respect, if you say well, they told us they were going 13 to, and we don't have any sort of formal interaction.
14 And we say well, we heard during the 15 subcommittee meeting they were receptive to some 16 changes, which may or may not happen, that one leaves 17 me a little less comfortable than at least if we had 18 the meeting and it was documented in the summary 19 report, and whether it's a letter, and we emphasize 20 three or four things, or it's in the summary report 21 I'm not so particular about.
22 But I think we need some follow up, just 23 because this is something where other people will be 24 using this framework.
25 MEMBER BIER: Yeah, if I can comment out NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
152 1 of turn, Vicki Bier --
2 CHAIRMAN BALLINGER: --- no turns.
3 MEMBER BIER: Well, okay, you were trying 4 to have turns, but my sense is that it is probably not 5 necessary for us to come back kind of for the purposes 6 of the Pele analysis and report. But that it might be 7 worth writing a letter focused on which aspects of 8 this we think do provide precedent for future 9 analyses, and which aspects would require more work 10 before being ready to go forward.
11 And that gets you guys out of the trap of 12 having to do a quick turnaround change on something 13 that might not be so quick. But still gets our 14 concerns and opinions out for the future, so that's my 15 vote.
16 MEMBER ROBERTS: This is Tom Roberts. I 17 think my two primary issues, neither which was fully 18 resolved today, nor did I necessarily expect them to, 19 one is almost a philosophical question on how the 20 qualitative safety goals play into societal risk of 21 transportation, and I don't think that's going to get 22 resolved in two or three weeks, that's just something 23 --
24 CHAIRMAN BALLINGER: Yeah, that's almost 25 biblical.
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153 1 MEMBER ROBERTS: Yeah, almost. And that's 2 just something that probably ends up with some sort of 3 a coherent write up of how the existing individual 4 goals meet the objective of societal risk. So, that's 5 one I don't think we would really need to have a 6 letter for. So, the second one is the -- we call it 7 uncertainties, or sort of cliff edge effects, or that 8 type of thing.
9 But that was, I didn't think clear in the 10 PNNL report or the draft SC. And I recognize for 11 example the thought process for criticality is that 12 the probability is probably not low enough to really 13 screen out criticality, so in real life the package 14 would be redesigned to preclude criticality using a 15 more deterministic approach, and I didn't get that 16 from either the panel report, or the SE -- not SE, the 17 non-SE in the evaluation.
18 That's something that you would be very 19 skeptical about, and expect some sort of an assessment 20 of either the consequence, or the degree of 21 uncertainty, and the potential for cliff edge effects, 22 whatever you want to call it. And I don't know if we 23 need to have a formal letter to communicate that, but 24 it's just something that kind of goes in Joy's and 25 Vicki's statements, something to think about maybe NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
154 1 making clear in the evaluation.
2 You have some of that in there, like you 3 expect to see dose evaluations for events that are 4 screened out, but something in more clear documents, 5 criticality being almost it's on a category of risk 6 that you would expect either more assessment, or 7 deterministically screening it out.
8 CHAIRMAN BALLINGER: We have a number of 9 members that can't participate in a deliberation, so 10 I want to see if Greg or Charlie has something.
11 MEMBER HALNON: Yeah, my only aspect on 12 all this is to make sure that -- and I was just 13 looking through the SER to see if I could find it, 14 just a clear boundary of what is this, and what is it 15 not? It doesn't cover the recovery actions, which to 16 me is the highest risk. As I had mentioned, it does 17 cover Pele project to a certain extent, it doesn't 18 cover zoning.
19 As long as it's clear in the SER, and I 20 have to go back and read it again to see if that mind 21 set is in there, or we write a letter saying this is 22 what we see it is, and this is what we see it's not 23 kind of goes along with a previous comment, I think it 24 was Vicki, that said it's got to be what are the next 25 steps type of thing, if you wanted to apply this NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
155 1 somewhere else, what would we have to do?
2 CHAIRMAN BALLINGER: I think we ought to 3 be -- I agree, but we should remember that they had a 4 statement of work to do certain things, and what 5 you're talking about is something that's important, 6 but was not part of their statement of work.
7 MEMBER HALNON: And what they worked on is 8 what they worked on, but what people perceive it as 9 being, and what it might get used for in the future is 10 different. And the SER does a good job, in my mind, 11 of going through and looking at their work, the 12 statement of work. But it doesn't, in my mind, bring 13 out as this is what it's not meant to be as a public 14 -- as a step going forward.
15 But it certainly is a methodology stepping 16 stone to those, but it's not a proven --
17 CHAIRMAN BALLINGER: It may be, let me --
18 my level of ambivalence on a scale of one to ten is 19 now up to like eight. So, it may be that any summary 20 that we would write, if we were to write a summary, 21 that's the place where we could say okay, this, and 22 that, but in the long term you need to consider the 23 following areas a little bit more carefully.
24 Not necessarily modify the PNNL report, 25 but it's comments to the staff that yeah this was NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
156 1 fine. But in the long term a report in issues --
2 MEMBER HALNON: From my issue, a summary 3 statement of two sentences would satisfy.
4 CHAIRMAN BALLINGER: Okay.
5 MEMBER HALNON: So, that would be 6 perfectly adequate, it'd be making it clear this is 7 what we concluded.
8 MEMBER BROWN: Is it my turn yet? You're 9 asking for -- I'm not just ambivalent, I have a hard 10 time understanding we either write a letter of summary 11 where we try to get consensus in some, whatever words 12 we want to say, it's not officially voted on by the 13 entire Committee, but yet supplied for them is not 14 going to happen in two weeks. That's too hard.
15 CHAIRMAN BALLINGER: The summary would 16 have to --
17 MEMBER BROWN: Let me finish, okay?
18 CHAIRMAN BALLINGER: The summary would 19 happen in PNP, and --
20 MEMBER BROWN: How you're going to get a 21 consensus summary written, the summary stuff, we're 22 getting carried away with these things. Every time I 23 turn around it seems like we're now having summaries, 24 and we're documenting actions in summaries. If we 25 have something very specifically we want to comment on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com
157 1 and provide to them, we ought to do that. If we 2 don't, and it's just a bunch of comments that we 3 monitor observations, that doesn't provide much 4 direction.
5 Not direction, but suggestions for the 6 staff as to what the Committee really feels over the 7 long haul. I mean, to me, this was a good 8 presentation, I mean the idea of taking a micro-9 reactor, moving it from the facility to where you want 10 to go use it, good idea. But now once it's out of 11 gas, you've got to take it out and move it back.
12 Well, why not just take the fuel out, leave it in 13 place, and put new fuel in it while it's there, it's 14 just a smaller reactor that you've built some place.
15 That thought process is not even in it.
16 I don't -- it's not the same stuff that you're doing, 17 just an overall thought process of how the small 18 module, the small really tiny micro-reactor, which has 19 some usefulness would be used. I just don't see how 20 we can come across with a coherent write up that's not 21 formally voted on by the Committee.
22 The Committee can outvote me, but that's 23 my position on the circumstances. I don't agree with 24 a summary trying to resolve all these little nuances.
25 CHAIRMAN BALLINGER: Walt, and Matt.
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158 1 MEMBER KIRCHNER: Well, just in summary, 2 I would say what was presented today, it's a good 3 framework, particularly for Pele, which is more of a 4 national defense application. The implications for 5 widespread use commercially begs a lot of questions 6 about, as I said earlier, proliferation risk, and 7 proliferating risk, nuclear materials, and health and 8 public, the safety.
9 And I'm just -- a strong footnote, many of 10 you know I looked at this very closely, not as 11 structured as this 40 years ago, and one of the things 12 that we decided early on was we would use TRISO fuel, 13 which takes a lot of design safety considerations off 14 the table, versus other reactor types. So, other 15 reactor types will present many more technical 16 challenges and probably require many more compensatory 17 measures in terms of design like additional control 18 absorbers, and such to prevent criticality accidents.
19 So, I could go on and on, I'll stop there 20 and just say that -- thanks for the presentations. I 21 think it is a good framework, I think it could be made 22 to work for Pele, but going beyond that, I don't know 23 if it's broad enough at this point, framework for 24 commercial applications. Thank you.
25 CHAIRMAN BALLINGER: Matt?
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159 1 MEMBER MARCH-LEUBA: I'll take his place.
2 Yeah, I don't have a very strong opinion one way or 3 the other. I wanted to emphasize Charlie's point, I 4 think he's correct this time, for a change. The 5 summary was designed whenever we have a subcommittee 6 and we don't want to follow up with anything, so we 7 will not be doing a full Committee meeting, we will 8 not be writing a letter.
9 And the summary summarizes our position 10 that we are in complete agreement with what we saw.
11 In this case, if we have suggestions, the summary is 12 not a good method, or mechanism. And that said, I 13 think we can split the baby in half by saying that it 14 is perfectly okay what we're seeing for Pele about we 15 expect a more detailed implementation with several 16 topics for commercial operations, which is not what 17 the staff is doing now. So, there you go, okay, next.
18 MEMBER BROWN: The transcript is also 19 available for them to get whatever they -- the 20 comments and suggestions we've had. Those they think 21 are valuable, they can utilize them. If they don't, 22 we can address it in some other circumstance, I'll 23 stop right there.
24 CHAIRMAN BALLINGER: Matt? He must be gone.
25 MEMBER REMPE: We're running out of time.
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160 1 CHAIRMAN BALLINGER: We are out of time.
2 MEMBER REMPE: So, I think the outcome on 3 this should be that we will have the full Committee 4 meeting presentation. You can talk to Chris about the 5 timing, it should be more succinct. But I think you 6 need to have a draft letter ready, and if we decide to 7 do a summary, it's the same thing as last month, we've 8 got the routine down, and we can decide after that 9 meeting. Is that okay with you, Ron?
10 CHAIRMAN BALLINGER: Okay with me. I am 11 not a PRA person, so any letter that I would write 12 would probably be closer to a Peanuts cartoon than --
13 MEMBER REMPE: So, I think that Tom, Greg, 14 Vicki and I should give you some input, and we'll work 15 together if that's okay with you, everyone wants to do 16 that over their Thanksgiving holiday. But we are out 17 of time. I really appreciate your presentation and 18 your effort to make it more succinct. Back to you.
19 CHAIRMAN BALLINGER: Don't know why I 20 actually ran this meeting, because I didn't. Okay, 21 well, thank you very much. And if you've witnessed 22 the confusion, that's correct. So, thanks again, and 23 we are adjourned.
24 (Whereupon, the above-entitled matter went 25 off the record at 12:05 p.m.)
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Development and Application of a Risk-Informed Approach for Regulatory Approval for Highway Shipment of a Microreactor Harold Adkins Garill Coles Pete Lowry Steve Maheras Steve Short Virgil Peoples Advisory Committee on Reactor Safeguards Meeting November 17, 2023 Washington D.C.
Purpose and Major Elements of Presentation
Purpose:
Provide background information on proposed risk-informed regulatory approach for the transportation of a transportable nuclear power plant (TNPP) in support of NRC draft safety evaluation
- 1. Brief description of the demonstration TNPP
- 2. Description of the proposed risk-informed regulatory pathway for TNPP transport and why it is needed
- 3. Development of proposed risk evaluation guidelines
- 4. Description of quantitative risk assessment process using an integrated assessment process based on probabilistic risk assessment (PRA) methods which includes consideration of defense in depth (DID) and Safety Margin
- 5. Example results of applying the proposed PRA and risk evaluations guidelines to the demonstration TNPP using PNNLs proposed approach
- 6. Description of approach to and results of sensitivities studies and uncertainty analyses
- 7. Insights gained from implemented demonstration of PNNLs proposed approach 2
Transportable Nuclear Power Plant (TNPP) Package
- Many advanced reactor vendors are developing TNPPs to make higher density energy readily available for:
Department of Defenses (DODs) domestic infrastructure resilient to electric grid attack Enabling rapid response during Humanitarian Aid and Disaster Relief (HADR) operations Clean, zero-carbon energy in a variety of austere conditions and off-grid locations
- These TNPP conventions would be factory Semi-Tractor and Trailer Carrying produced, fueled, acceptance tested, and Reactor Module deployed as sealed units prepared for transport and retrieved for refueling and Photo courtesy of News & Technology for Global Energy reapplication Industry, April 21, 2022 https://www.powermag.com/green-light-for-project-pele-defense-departments-mobile-nuclear-microreactor-demonstration/
3
Project Pele used to Demonstrate Risk-Informed Regulatory Pathway
- 1 to 5 MWe, minimum of 3 years of full power operation
- Multiple modules Reactor Module IHX Module Control Module Power Conversion Module
- Reactor Module contains a vast majority of Artists rendering of BWXTs Project Pele transportable reactor radioactivity at EOL (remainder in IHX modules arriving for set up and operation. (Image: BWXT)
Module) Photo courtesy of NuclearNewswire, June 9, 2022 https://www.ans.org/news/article-4035/bwxt-wins-project-pele-contract-to-
- Each module contained in and integral with supply-nations-first-microreactor/
separate ISO-compliant CONEX box-like containers Acronyms: MWe - megawatt electric; HTGR - high temperature gas-cooled reactor, HALEU - high-assay low-enriched uranium; UCO - uranium oxycarbide; TRISO - tri-structural isotropic; IHX - intermediate heat exchanger; EOL - end of life; ISO- International Organization for Standardization; CONEX - container express 4
Need for Risk-Informed Regulatory Approach
- US transportation regulatory requirements contained in 10 CFR Part 71 primarily focus on the definition for thick-wall steel vessel for SNF transportation package
- A TNPP with its irradiated fuel contents prepared as a package for transport could be challenged to meet the entire suite of codified regulatory performance requirements in 10 CFR 71 It is anticipated that the TNPP will be capable of being deterministically shown to comply with the Normal Conditions of Transport (NCT) as outlined in 10 CFR 71.71 However, it may be challenging to demonstrate that the level of robustness of current proposed TNPP technology can fully meet the dose rate and containment success criteria after Hypothetical Accident Conditions (HAC) tests as outlined in 10 CFR 71.73 E.g., Sequential 30 ft free drop, crush, puncture free drop, 30-minute engulfing hydrocarbon fire, and water immersion tests
- Leverage compensatory measures and defense-in-depth approaches and philosophies to reestablish equivalent safety
- Leverage consideration of TRISO, compact, fuel sleeve, core, and reactor structure related inherent retention and protection boundaries 5
Basis for Proposed Regulatory Approach
- If Fissile Material or Type B package postulated HAC requirements (10 CFR 71.73) cannot be directly met, then other package approval options are possible:
10 CFR 71.41(c) Alternative Environmental and Test Conditions (10-160B and 8-120B Transportation Casks) 10 CFR 71.41(d) Special Package Authorization (West Valley Melter Package) 10 CFR 71.12 Exemption (Trojan Reactor Vessel)
- Approval of transporting the Trojan Reactor Vessel up the Columbia River and on the Hanford Site was based on compensatory actions as it could not be fully tested.
- Preferred initial pathway identified by PNNL is the Exemption process that allows compensatory actions to protect the basis of exemption if acceptable risk is demonstrated Can apply to more than a single shipment unlike Special Package Authorization Flexibility in deviating from deterministic requirements compared to Alternative Environmental and Test Conditions 6
Reasoning Behind Selection of this Regulatory Approval Pathway
- Quantitative risk analysis approaches such as Probabilistic Risk Assessment (PRA) are used in risk-informed regulatory approaches for the NRC:
PRAs have been conducted since the 1970s for nuclear reactors starting with WASH-1400 and used since the 2000s for risk informed licensing applications.
PRA has also been used to assess:
Dry cask storage systems at a nuclear power plants (see NUREG-1864)
Transportation of spent nuclear fuel (SNF), most notably in NUREG/CR-4829, NUREG/CR-6672, and NUREG-2125
- Proposed to NRC as an aid in developing a near-term approval pathway to drive Advanced Factory-Produced TNPP development and deployment
- Bridges the gap between the current regulatory framework (thick-wall steel vessel based) and the level of robustness of current proposed TNPP technology
- Provides buffer time for strategic regulatory considerations and possible rule making to more so accommodate advanced, transportable, microreactor conventions 7
Risk-Informed Regulatory Approval - Using Exemption Process
- Quantitative Risk Assessment - Demonstration of acceptable risk will require a quantitative assessment given (1) the complexities and uncertainties about package performance and (2) potential risk to public. PRA provides a rigorous quantitative approach Unlike the approval pathways used in the past (e.g., Trojan Reactor Vessel), it is unlikely that all accident scenarios can be screened based on likelihood.
- Risk Evaluation Guidelines - Quantitative risk assessments work best when supported by guidelines about acceptable risk as a key basis for regulatory decisionmaking
- However - risk-informed regulatory guidelines using PRA do not exist for transportation packages like they do for nuclear power plants (NPPs)
- That said - The proposed risk evaluation guidelines are based on the risk-informed decision making (RIDM) guidance in NRC 2008 report for nuclear material and waste applications (ML080720238)
- This guidance includes proposed quantitative health guidelines developed from the 1986 NRC Safety Policy Statement
- Challenges remain in its implementation and the approach has not been endorsed for use by NRC as that would be a policy decision 8
Proposed Risk Acceptance Guidelines 2008 in RIDM Report NRC-Proposed Qualitative Health Guidelines (QHGs) Based on Interpretation of Safety Policy Statement Receptor Acute Fatality Latent Cancer Serious Injury Fatality (LCF) (Cancer Illness)
Public QHG Public QHG Public individual QHG Public individual individual risk of acute risk of a LCF is negligible if risk of serious injury is fatality is negligible if it it is less than or equal to negligible if it is less than or is less than or equal to 2x10-6 fatality per year or 4 equal to 1x10-6 injury per 5x10-7 fatality per year. mrem per year year.
Worker QHG Worker QHG Worker individual QHG Worker individual individual risk of acute risk of LCF is negligible if it risk of serious injury is fatality is negligible if it is less than or equal to negligible if it is less than or is less than or equal to 1x10-5 fatality per year or equal to 5x10-6 injury per 1x10-6 fatality per year. 25 mrem per year. year.
- 1986 NRC Safety Goal Policy - The premise is that risk to people from a nuclear power plant should be very small compared to the sum of other accident risk (e.g., 0.1% prompt fatality)
- Workers are not specifically addressed in the Safety Goal Policy, so the 2008 RIDM report proposes that worker risk be small compared to other risk but not as small as for the public who are not trained in radiation protection 9
Justification for Using Surrogate Measures for QHGs
However, NPP PRAs (which are mature and well used) are not typically taken to Level III, but rather use the surrogates of CDF and LERF for risk-informed applications, as they are more feasible (see RG 1.200)
- PNNL proposes using surrogates for the QHGs suggested by the 2008 RIDM report by formulating goals in terms of radiological dose and likelihood limits to an individual receptor, which are more feasible to achieve:
Reduces calculational burden by eliminating determination of health effects Dose limits can be compared to other federal/international dose limits used in related contexts Determining likelihood and consequence as pairs provides added information for decisionmaking
- PNNL examined the use of dose consequence-likelihood pairs from other applications NEI 18-04 provides risk-informed licensing basis development for advanced non-light-water NPPs DOE-STD-3009 applies risk ranking using dose and likelihood for nonreactor facility nuclear safety analysis NUREG-1513, NUREG-1520, and 10 CFR Part 70 Subpart H provide guidance used in Integrated Safety Analysis (ISA) for determining performance requirements for nuclear fuel cycle facilities The Q system in Appendix I of IAEA Specific Safety Guide (SSG)-26 uses a reference dose to determine an upper quantity limit of radionuclides in Type A package (greater quantities require Type B) 10
Development of Proposed Risk Evaluation Guidelines
- Hypothetical risk evaluation guidelines for radiation dose based on guidance for ISA (NUREG-1513) 10 CFR Part 70 defines radiation dose levels for High and Intermediate consequences for the worker and for an individual member of the public NUREG-1520 provides per year frequency definitions for Unlikely and Highly Unlikely events Annual Accident Radiation Dose Radiation Dose Frequency (per Consequence to the Consequence to the event, per year) Offsite Public(a) Worker(a) Risk Acceptability
<1E-05 25 rem TEDE 100 rem TEDE Acceptable 1E-05 25 rem TEDE 100 rem TEDE Unacceptable
<1E-04 and 1E-05 5 and <25 rem TEDE 25 and <100 rem TEDE Acceptable 1E-04 5 rem TEDE 25 rem TEDE Unacceptable 1E-04 <5 rem TEDE <25 rem TEDE Acceptable (a)The radiation dose consequences are presented as a total effective dose equivalent (TEDE), which is based on the integrated committed dose to all receptor organs, thereby accounting for external exposures as well as a 50-year committed effective dose equivalent.
11
Development of Proposed Risk Evaluation Guidelines
- Hypothetical risk evaluation guidelines for radiation dose based on guidance for ISA (NUREG-1513) 10 CFR Part 70 defines radiation dose levels for High and Intermediate consequences for the worker and for an individual member of the public NUREG-1520 provides per year frequency definitions for Unlikely and Highly Unlikely events 1.0E+00 1.0E-01 For the public Accident Frequency (per year) 1.0E-02 Unacceptable Risk Region 1.0E-03 1.0E-04 1.0E-05 Acceptable Risk Region 1.0E-06 1.0E-07 1.0E+00 1.0E+01 1.0E+02 1.0E+03 Total Effective Dose (rem) 12
Development of Proposed Risk Evaluation Guidelines Frequency-Consequence Targets from NEI 18-04, Revision 1
- Illustration of the concept of risk evaluation guidelines based on the combination of radiological dose and likelihood 13
Development of Proposed Risk Evaluation Guidelines
- 1. Synthesized a set of the limits using the likelihood-consequence pairs from or based on the applications investigated for facilities
- 2. Converted the radiological dose consequence limits to health effects to the worker and a member of the public by multiplying the:
Accident frequency Radiation dose consequence from the accident Conversion factors published by DOE used to convert radiation dose to mortality and morbidity(1)
- 3. Readjusted some of the likelihood-consequence pairs to ensure that each limit was less than or equal to the QHGs for acute fatalities proposed in the NRC 2008 RIDM report Note:
(1) DOE Environmental Policy and Guidance Memorandum, Radiation Risk from Effective Dose Equivalents (TEDEs), dated August 2002 based on an Interagency Steering Committee on Radiation Standards (ISCORS) for implementing standards for protection from ionizing radiation 14
Proposed Risk Evaluation Guidelines Proposed risk evaluation guidelines compatible with NRC nuclear safety goals, Qualitative Health Objectives, and NRC-proposed QHGs in the NRC 2008 RIDM report For the Maximum Exposed Member of the Public For the Worker 15
Integrated Safety/Risk Assessment Process Compile Transportation Package and Shipment Route Identify Hazardous Conditions Information Quantitative Risk Identify Package Safety Functions Postulate Accident Conditions Assessment Process Assign Likelihood and Identify Shipment Hazards Consequence Bins to Each
- Uses an integrated risk assessment Accident process based on probabilistic risk Select Bounding Representative Accident Scenario (BRA) for Each Group Screen Accident Conditions assessment (PRA) approaches and methods Develop Bounding Likelihood for Each BRA Develop Bounding Consequence for Each BRA Identify Accident Scenarios
- Uses standard methods acceptable Compare Risk Resultfor Each BRA to the Risk Evaluation Group Accident Scenarios by to both NRC and DOE for assessing Guidelines Accident Phenomena the risk of nuclear facilities Assess Sensitivities to Model Uncertainties
- The process was implemented as a Assess Adequacy of Safety demonstration on a hypothetical Assess Defense-in-Depth (DID)
Margins shipment of the Project Pele TNPP Decision on Adequate Safety Probabilistic Risk Assessment Development Process 16
Step 1 - Compile TNPP and Shipment Route Information and Step 2 - Identify Package Safety Functions STEP 1 Step 1: Information Collection Compile Transportation Package TNPP transportation package (Reactor Module only); and Shipment Route System design and configuration information, Information estimated radionuclide inventory at various time periods following reactor shutdown, information on STEP 2 the process for preparing the module for shipment Route hazard information, very large truck accident Identify Package Safety data, and non-vehicle accident data Functions Step 2: Package Safety Functions provide containment of radiological materials provide radiation shielding Identify Shipment Hazards maintain a criticality-safe configuration maintain passive cooling (considered) 17
Step 3 - Identify and Develop Accidents Identify Hazardous Conditions
- Performed accident identification and development using Hazard Analysis Postulate Identify Package
- Use of subject matter experts to identify and Safety Functions Accident Conditions assess hazardous conditions that could occur during TNPP transport Hazards ID Checklist STEP 3 Assign Likelihood Identify and Develop and Consequence Accidents
- Complete hazardous condition evaluation Bins worksheets that assign likelihood and Define Bounding consequence categories Representative Accident Screen Scenarios (BRAs) Accident Conditions
- Consider both highway accident and non-highway accident initiating events Identify
- Formulate hazardous conditions to contain Accident Scenarios information needed to define accident scenarios
- Total of 31 accident scenarios representing 8 Group Scenarios by Accident Phenomena accident phenomena classes were defined 18
Step 4 - Define Bounding Representative Accident Scenarios (BRAs)
- A BRA is representative of a Identify Shipment Hazards group of accident scenarios that are phenomenologically similar STEP 4 Select Bounding Representative
- The likelihood for the BRA is Accident Scenario (BRA) for Each Group determined by the sum of the accidents in the group
- The consequence for the BRA Develop Bounding Likelihood Develop Bounding Consequence for Each BRA for Each BRA is then determined by the worst consequence of the accidents in the group
- This bounds the risk of all accident scenarios in the group 19
Step 4 - List of Resulting Bounding Representative Accidents for this Demonstration Implementation BRA ID Description 1 Fire-only event that originates inside the transport module.
2 Diesel fuel fire-only event that originates outside the transport module and propagates into the transport module and ignites combustible material in the transport container, which damages the package.
3 Hard-impact highway accident that leads to release of radioactive material and loss of shielding. Includes impact with heavy vehicles and unyielding objects (e.g., concrete abutments or rock embankments), drops to a lower elevation, or rollovers.
4M Less than a hard impact highway accident that results in release of some radiological material and loss of shielding. Medium impact that involves a severe collision with a light vehicle.
4L Less than a hard-impact highway accident that results in no release of radiological material but some degradation of external shielding. Light impact such as a jackknife, impact with a yielding object (e.g., a road sign or soil embankment), or impact with a light vehicle that is not severe.
5H Hard impact highway accidents that result in fire with exception of collision with a tanker carrying flammable material.
5M Medium impact highway accidents (i.e., severe collision with a light vehicle) that results in fire.
6 Collision with a tanker carrying flammable material that leads to fire.
7 Loss of non-pressurized reactor containment boundary not caused by a road accident but rather by human error and failures of containment features.
8 Loss of pressurized reactor containment boundary not caused by a road accident but rather by human error and failures of containment features.
9A Addition of moderator and a possible change in core geometry caused by a drop into body of water that results in criticality.
9B Addition of moderator and possible change in core geometry caused inundation of the core with fire suppression water or other hydrogenous material that enters the core in sufficient quantities to cause criticality after a crash that results in fire and TNPP damage 10 Control rod withdrawal (or another reactivity insertion event) caused by impact from a road accident that results in criticality.
20
Step 5 - Develop Likelihood for Each BRA
- Very large truck accident data Select Bounding Representative Frequency of impacts, fires, non- Accident Scenario (BRA) for impacts, rollovers Each Group Use route specific data to the extent possible STEP 5
- Package-specific failures not in Develop Bounding Likelihood for Each BRA Develop Bounding Consequence for Each BRA accident rate data Internal-initiated fires, random failures, human error Compare Risk Result for Each
- Specific route hazard BRA to the Risk Evaluation Guidelines information such as bridges, bodies of water, steep drops to a lower elevation 21
Step 5 - Develop Bounding Likelihood for Each BRA
- The assumed hypothetical route for this demonstration was from Idaho National Lab to White Sands NM (about 1300 miles of Interstate)
- GIS was used to identify portions of the route where hazards existed to compute the percentage of total route where the hazard existed. This includes:
Steep drop-offs. If an accident happened here, the truck and package could drop or roll to lower elevation.
Sufficient slope to a body of water deep enough to submerge the reactor vessel. If an accident happened here, a criticality could occur.
- Using very large truck crash rate data and hazard data, an accident frequency was computed.
22
Step 6 - Develop Bounding Consequence for Each BRA Select Bounding Representative
- Estimated effective radiation dose from Accident Scenario (BRA) for each dose pathway methodology is Each Group based on Appendix I of IAEA SSG-26, with refinements mostly to account for the public receptor.
Develop Bounding Likelihood Develop Bounding Consequence
- The source term was calculated using for Each BRA STEP 6 for Each BRA DOE/NRC methods/data used to determine source term (e.g., MAR x DR x ARF x RF x LPF)
- Source term includes used fuel inventory Compare Risk Result for Each and inventories diffused into reactor BRA to the Risk Evaluation Guidelines during operation Fuel (concerns about performance under mechanical impact)
Core/compact (concerns about fuel qualification) Material at Risk (MAR), Damage Ratio (DR), Airborne Release Pressure Boundary (concerns about plating) Fraction (ARF), Release Fraction (RF), and Leak Path Factor (LPF) 23
Step 6 - Develop Consequence for Each BRA
- Radiological dose pathways from IAEA SSG-26 (Q System) were used which are the same as in NRC regulations).
External Photon Dose (QA): External dose due to released material (with added contribution for unreleased material for an individual at given distances from the package with degraded shielding.)
External Beta Dose (QB): External direct dose from skin contamination due to released material for individual at given distances from the release.
Inhalation Dose (QC): : Inhalation dose calculated using an airborne source term and human uptake value Skin contamination (QD): Calculated from equivalent skin dose but not used because responders are assumed to use protective clothing Neutron Dose: Determined by PNNL to be a minimal contributor in the demonstration for released material. Gamma dominates
- Other pathways excluded by Q system: (e.g., resuspension, skyshine, drinking water ingestion) are not significant contributors for irradiated fuel and would likely be mitigated by the emergency response
- Submersion pathway (see QE in the Figure) excluded because the release is outdoors where there will be a high level of dilution 24
Step 7 - Compare Risk Results to Proposed Risk Evaluation Guidelines The risk results are reported as the likelihood and consequence for each Bounding Representative Accident Example Comparisons to Risk Evaluation Guidelines Develop Bounding Likelihood Develop Bounding Consequence When the accident frequency is for Each BRA for Each BRA 1E-05 and >1E-06 per year Then the dose limits are:
5 and <25 rem TEDE for a member STEP 7 of the public Compare Risk Result for Each 25 and <100 rem TEDE for a worker BRA to the Risk Evaluation Guidelines or When the accident frequency is 1E-04 and >1E-05 per year Then the dose limits are:
Assess Sensitivities to Model 1 and <5 rem TEDE for a member of Uncertainties the public 5 and <25 rem TEDE for a worker 25
Step 8 - Assess Sensitivities and Model Uncertainties
- Sensitivity studies were performed to Compare Risk Result for Each address the impact of key assumptions BRA to the Risk Evaluation and sources of uncertainty (examples Guidelines are provided later)
- Sensitivity studies were also considered to address the impact of compensatory STEP 8 Assess Sensitivities to Model actions Uncertainties
- Limited parameter uncertainty analysis typical of PRAs was performed Data for a parametric uncertainty Assess Adequacy of Safety analysis is limited Assess Defense-in-Depth (DID)
Margins Because each BRA is evaluated with a bounding estimate of the likelihood and consequence 26
Step 9 - Assess Defense-in-Depth Step 10 - Assess Adequacy of Safety Margins
- DID is a design and operational philosophy that calls for multiple layers of protection to prevent and mitigate accidents Assess Sensitivities to Model Uncertainties multiple physical barriers to prevent release of radiation passive features STEP 9 STEP 10 PRA shows low risk Assess Adequacy of Safety administrative controls Assess Defense-in-Depth (DID)
Margins accident recovery plans
- Safety margin is a measure of the conservatism that is employed in a design or process to assure a high Decision on Adequate Safety degree of confidence that it will perform a needed function Typically to demonstrate adherence to acceptable codes and standards 27
Example Risk Results for Bounding Representative Accidents BRA 2 - Fire Only that Originates from Outside the Transport Container Worker Public Accident Applicable Proposed Risk Dose Dose Frequency Evaluation Guidelines from Accident Risk (rem TEDE) (rem TEDE) (per year) Table 4.7 of this Report Accident Consequence (from Table 7.6)
MAR contribution from released material TRISO Fuel 0 0 5 and <25 rem TEDE for a Core Structure 1.0E-03 2.6E-04 member of the public Cooling System 1.2E-03 2.5E-04 25 and <100 rem TEDE for a Contribution from Unreleased Material worker Degraded shielding 0 0 when the accident frequency is 1E-05 and >1E-06 Total Radiation dose 2.3E-03 5.1E-04 Accident Frequency assuming one trip per year (from Table 6.16) 2.0E-06 COMPARISON TO RISK EVALUATION GUIDELINE Acceptable 28
Example Risk Results for Bounding Representative Accidents BRA 3 - Hard Impact Road Accident that leads to release of radioactive material and degraded shielding Worker Public Dose Dose Accident Applicable Proposed Risk (rem (rem Frequency Evaluation Guidelines from Accident Risk TEDE) TEDE) (per year) Table 4.7 of this Report Accident Consequence (from Table 7.6)
MAR contribution from released material TRISO Fuel 80.9 18.5 1 and <5 rem TEDE for a member of the public Core Structure 5.2E-01 1.3E-01 5 and <25 rem TEDE for a Cooling System 3.1E-01 6.3E-02 worker Contribution from Unreleased Material when the accident frequency Degraded shielding 6.0 6.9E-02 is Total Dose 87.7 18.8 1E-04 and >1E-05 Accident Frequency assuming one trip per year (from Table 6.16) 7.1E-05 COMPARISON TO RISK EVALUATION GUIDELINE Unacceptable 29
Summary of Demonstration TNPP PRA Risk Results
- Risk for the Bounding Representative Accident Results Shown Graphically For the Maximum Exposed Member of the Public For the Worker Note: BRA 9A and 9B - two kinds of flooded criticality events - are not shown here because their consequences were not calculated given that their likelihoods were determined to be extremely low.
BRA 10 - reactivity insertion caused by crash impact leading to criticality was not developed because it was anticipated the demonstration design will preclude (or design against) this possibility (e.g., using locking mechanisms) 30
Sensitivity Studies
- Selection and definition of the sensitivity cases to be performed were based on:
Comprehensive examination of specific lists of assumptions and bases for the hazards, likelihood, and consequence analysis, and Compensatory measures listed for the demonstration design to reduce or mitigate risk
- Quantitative sensitivity studies defined and performed
- 1. Decay time after operation
- 2. Distance of a member of the public to point of release
- 3. Exposure time to a damaged TNPP package
- 4. Uncertainty in source term fraction estimates
- 5. Restriction of transport during extreme weather (compensatory action)
- 6. Transport at night (compensatory action)
- In sensitivity studies - reran the models for applicable BRA to determine new risk results 31
Example Sensitivity Study Results Results of Sensitivity Study on decay time after shutdown on BRA 3 -
Hard Impact Road Accident Sensitivity Study for Impact of Decay after Shutdown Delay from Worker Public Accident Applicable Proposed Risk Shutdown to Dose Dose Frequency (per Evaluation Guidelines from Transport (rem TEDE) (rem TEDE) year) Table 4.7 of this Report Accident Consequence (from Table 7.6) 30 days 1420 319 1 and <5 rem TEDE for a 60 days 208 45.9 member of the public 90 days 87.7 18.8 5 and <25 rem TEDE for a 1 year 14.5 3.3 worker 2 years 7.8 1.7 when the accident frequency Accident Frequency assuming one trip is per year (from Table 6.16) 1E-04 and >1E-05 7.1E-05 COMPARISON TO RISK EVALUATION GUIDELINE Acceptable for delay times of 1 year or more 32
Uncertainty Analysis and Insights
- In general, there is insufficient data to perform parametric uncertainty analysis (hence the sensitivity studies)
- However, a limited uncertainty analysis was performed on the very large truck accident data Worker Public Accident Applicable Proposed Risk Dose Dose Frequency Evaluation Guidelines from Table Accident Risk (rem TEDE) (rem TEDE) (per year) 4.7 of this Report Accident Consequence by MAR Contribution (Radiation dose from Table 7.6) 1 and <5 rem TEDE for a member of the public MAR contribution from Released Material 5 and <25 rem TEDE for a worker TRISO Fuel 0 0 when the accident frequency is Core Structure 2.6E-02 6.5E-03 1E-04 and >1E-05 Cooling System 9.3E-03 1.9E-03 Contribution from Unreleased Material 0.1 and <1 rem TEDE for a member Degraded shielding 6.0 6.9E-02 of the public 2 and <5 rem TEDE for a worker Total Dose 6.0 7.7E-02 when the accident frequency is Accident Frequency assuming one trip per year (from 1E-03 and >1E-04 Table 6.16) 9.7E-05 Accident Frequency multiplied by 41% to match highest Worker risk changed from acceptable state and year combination to unacceptable from comparison to 1.4E-04 risk evaluation guidelines COMPARISON TO RISK EVALUATION GUIDELINE Unacceptable
- The limited uncertainty analysis did not change the conclusions about risk of the BRAs with the exception above for BRA 4 Medium Impact Accident which becomes unacceptable.
33
Key Insights from Demonstration PRA Results and Sensitivity Studies
- Allowing the TNPP reactor core to decay up to one year after it has been in operation for 3 years will result in an acceptable level of risk for all BRAs based on the proposed risk evaluation guidelines.
- The conclusions about the risk of BRAs are not sensitive to the uncertainty in estimating the source term factors.
- The conclusions about the risk of BRAs are not sensitive to increasing the accident duration from 30 minutes to one hour.
- The conclusions about the risk of BRAs are not sensitive to decreasing the distance that the public is to the accident to be the same distance as the worker is to the accident, except for light impact accidents (BRA 4L and BRA 4M) in which a direct dose of 6 rem is estimated from degraded shielding.
- While certain compensatory actions are feasible to implement, their impact is difficult to evaluate 34
Summary
- Current NRC regulations provide a feasible regulatory pathway for licensing a first-of-kind transportation of a microreactor with irradiated fuel
- Proposed workable risk evaluation guidelines were developed that are compatible with QHGs proposed in the 2008 NRC RIDM report
- The risk-informed PRA-based approach does support an application to the NRC for approval of shipment of a TNPP package (containing irradiated fuel)
- The demonstration application of this approach for a hypothetical single shipment per year of the Project Pele microreactor has shown that the proposed risk evaluation guidelines can be met 35
Questions Discussion
Backup Slides 37
Sensitivity Study Insights Certain candidate sensitivity studies were screened out for feasibility reasons
- This figure shows the environmental condition at the time of the very large truck crash based on Motor Carrier Management Information system data.
- It indicates most accidents occur during clear weather - probably because the weather is usually clear.
- The change in the accident rate for poor conditions could not be determined from the data because the very large truck travel volume was not known for the different environmental conditions 38
List of Hazard Analysis/Accident Sequence Assumptions Description of Assumptions (Sheet 1 of 2)
- 1. The dominant radiation dose risk is associated with the Reactor Module because it contains the reactor, the fuel, portions of the primary cooling system and nearly all of the radiological material inventory.
- 2. The Reactor Module also includes spent fuel after a specified period of decay s described..
- 3. There is no gas cleanup system in the design, so its contribution to radioactive transportation inventory is not considered
- 4. Submersion of the reactor vessel into a body of water could lead to a criticality based on demonstration design.
- 5. No credit can be taken for a HMIS (a health monitoring system) given that one has not yet been defined, though such a system could reduce the risk from certain kinds of accidents.
- 6. Loss of passive heat transfer from the reactor in the TNPP Package to the environment could lead to pressurization of the reactor containment boundary but decay heat by itself would not lead to failure of a containment seal or device
- 7. There is only enough combustible material inside the Reactor Module in the form of cable and wire jacket and insulation to lead to a small fire.
- 8. No (or minimal) other flammable material, other than cable and wire jacket and insulation and minimal quantities of grease and oil, exist in the Reactor Module
- 9. There will be energized electrical components in the TNPP Package during transport associated with parameter monitoring, lighting, and ventilation
- 10. The quantity of diesel fuel in the transport vehicle is about 300 gallons
- 11. The only external fire of sufficient magnitude to propagate into the TNPP Package from the outside is a diesel fuel fire (though engine and other fires could propagate to a diesel fire).
39
List of Hazard Analysis/Accident Sequence Assumptions Description of Assumptions (Sheet 2 of 2)
- 12. For hard impacts followed by fire, including a collision with a tanker carrying flammable liquid, the proportion of collisions that involves an explosion (e.g., deflagration or detonation) is very small compared to those that involve just fire.
Therefore, hard impact followed by an explosion were not separately evaluated.
- 13. A shipment would not deliberately be made in weather conditions so severe that the design/integrity of package would be exceeded.
- 14. Extreme weather events that can contribute to the occurrence of highway accidents that damage the TNPP Package are included in the large truck data, and therefore, do not need to be separately considered in separate scenarios.
- 15. There would be no specific control of passing or oncoming vehicles (i.e., collision with other vehicles was assumed possible) in development of the likelihood estimates.
- 16. Hazardous conditions qualitatively evaluated to be low risk were not significant enough to be carried forward for detailed accident analysis
- 17. The TNPP being transported has not experienced a design basis event (DBE) or beyond design basis event (BDBE) during operation that would have affected diffusion rates during operation 40
NRC REVIEW OF A RISK-INFORMED METHODOLOGY FOR A TRANSPORTABLE MICRO-REACTOR PACKAGE ACRS Subcommittee on Fuels, Materials, and Structures November 17, 2023 Bernard White, Senior Project Manager Jonathan Marcano, Senior Risk and Reliability Analyst Division of Fuel Management Office of Nuclear Material Safety and Safeguards 1
Agenda
- Adequate transportation regulatory framework
- Extensive regulatory engagements on Project Pele
- Alternate package approval pathways, including risk-informed methodology
- U.S. Nuclear Regulatory Commission (NRC) review of the risk-informed methodology
- Next steps in development of and preparation to review a package application in CY2024 2
Regulations for Radioactive Material Transport
- NRC and U.S. Department of Transportation (DOT) co-regulate transportation of radioactive material
- Regulates all hazardous materials, including radioactive material (RAM), for all modes of commercial transportation
- Is the U.S. Competent Authority for import and export of RAM
- Sets safety standards for the classification of RAM, for the design specifications and performance requirements of Type A packages (other than fissile materials) and for low specific activity (LSA)/surface contaminated object (SCO) RAM, and for the external radiation fields, labeling, and marking of all RAM packages and vehicles.
- Authorizes shipment in NRC-approved packages
- NRC
- Regulates domestic Type B and fissile packages
- Conducts the technical review and provides recommendations to DOT on foreign packages (i.e., revalidations) 3
Package Performance Tests and Conditions
- Normal conditions of
- Hypothetical accident transport (10 CFR 71.71) conditions
- Hot and cold temperatures (10 CFR 71.73)
- Reduced and increased foot drop test external pressure inch puncture test
- Vibration minute fire at
- Water spray 1,475 degrees Fahrenheit
- Free drop (1 to 4 feet) - Water immersion test (fissile/non-fissile)
- Corner drop
- Compression test
- Penetration test 4
Package Performance Criteria
- Criticality safety
- Single package (10 CFR 71.55)
- Array of packages (10 CFR 71.59)
- Shielding
- Maximum dose rates for all packages (10 CFR 71.47 & 49 CFR 173.441)
- Additional requirements for Type B packages
- Containment criteria for normal form material (10 CFR 71.51(a)(1) and (2))
- Dose rates after hypothetical accident conditions OPTIMUS-L Package (10 CFR 71.51(a)(2)) Photo courtesy of NAC International 5
What is Project Pele?
- Strategic Capabilities Office (SCO) in the U.S.
Department of Defense contracted with BWX Technologies, Inc., to design and fabricate a transportable micro-reactor
- Producing less than 5 MW
- Operable for 3+ years
- Reactor module fits into a single custom-developed International Organization for Standardization container which resembles a CONtainer EXpress (CONEX) box 6
Levels of Regulatory Engagement for Project Pele
- Scope of Memorandum of Understanding between NRC, U.S.
Department of Energy (DOE) , and SCO
- Covers the Microreactor Research, Development, and Demonstration
- Defines NRCs regulatory role
- SCO requested NRC review of the risk-informed methodology
- NAC will request a transportation package review to support SCO Project Pele activities.
- U.S. Department of Energy (DOE) is the authorizing official for Demonstration Project Pele Microreactor at Idaho National Laboratory
- Reactor operations and transport onsite 7
Why a Risk Methodology?
- Leak rate and dose rate requirements (10 CFR Part 71.51(a))
after hypothetical accident conditions (10 CFR 71.73)
- Regulatory approval pathways
- Alternate test criteria in 10 CFR 71.41(c)
- Exemptions (10 CFR 71.12) from specific requirements using a risk-informed approach 8
Risk-informed Methodology
- First-of-a-kind transportation risk assessment of an irradiated microreactor to evaluate
- Accidents
- Dose to member of the public and worker
- Leverage current risk-informed and performance-based concepts to evaluate future specific exemptions
- NRCs review
- Evaluates risk associated with microreactor transportation
- Identifies important scenarios that drive the risk
- Informed by design of components
- Identifies the need for compensatory transportation measures during transportation 9
Risk Assessment Approach
- Risk evaluation guidelines defined by pairs of likelihood-dose thresholds
- Elements of the Probabilistic Risk Assessment
- Identification of Safety Functions
- Characterization of hazardous conditions to identify accidents
- Determination of accident likelihoods
- Consequence analysis
- Evaluation of probabilistic risk assessment results against risk evaluation guidelines
- Sensitivity Studies
- Uncertainty Analysis
- Defense-in-Depth 10
Risk Evaluation Guidelines
- Pairs of likelihood-dose are informed by existing NRC performance criteria for nuclear fuel facilities, DOE nuclear facilities, and International Atomic Energy Agency risk evaluation guidelines
- Surrogate values that align with NRC nuclear safety goals, quantitative health objectives (QHO) and corresponding proposed quantitative health guidelines (QHG) 11
Risk Evaluation Guidelines
- Pacific Northwest National Laboratory (PNNL) proposed using QHGs that are based on the NRC report titled, Risk-Informed Decisionmaking for Nuclear Material and Waste Applications
- QHGs are based on the QHOs from the 1986 NRC Safety Goal Policy statement developed for the operation of nuclear power plants
- Consistent with similar risk-informed performance-based approaches endorsed by NRC in Regulatory Guide 1.233
- Guidance for a Technology-Inclusive, Risk-Informed, and Performance-Based Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certification, and Approvals for Non-Light- Water Reactors 12
Proposed Risk Evaluation Guidelines for the Public 13
Proposed Risk Evaluation Guidelines for Workers 14
Proposed Risk-Informed Methodology Review Process Initiating Event
- Identification of Hazardous Conditions
- Identifies bounding representative accidents by phenomena
- Estimates likelihood of occurrence for bounding accidents 15
Proposed Risk-Informed Methodology Review Process Accident Sequence Analysis
- The Methodology is an approach for determining the risk for a transport of a micro-reactor package
- The Methodology estimates damage based on expert judgement
- Numerical assumptions and results in the Methodology are unimportant to understanding the approach
- Package application should include structural and thermal analyses to evaluate damage to the package 16
Proposed Risk-Informed Methodology Review Process Source Term Analysis
- Nuclide inventory based on expected operations and cool time
- Two phase screening based on quantity and A2 value
- Material available for release
- Material that migrates out of the tri-structural isotropic (TRISO) fuel
- Activated reactor components
- The Methodology proposes to use the DOE handbook Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities 17
Proposed Risk-Informed Methodology Review Process Consequence Analysis
- Considers four dose pathways from the Q-System along with neutron dose (excludes submersion in a cloud)
- PNNL states that neutron dose is usually a fraction of the photon dose
- NRC experience is that neutron dose can be a significant contributor where there are areas of dense gamma shielding 18
Dose Pathways in the Q-System per IAEA SSG-26 Direct Photon Dose Direct Beta Dose Submersion in a Gas Inhalation Dose Skin Contamination Cloud for Noble Gasses and Ingestion Dose Specific Safety Guide No. SSG-26 (Revision 1), Advisory Material for the IAEA Regulations for the Safe Transport of Radioactive Material (2018 Edition) 19
Proposed Risk-Informed Methodology Review Process Uncertainty Analysis & Defense-in-Depth
- Process addresses key assumptions and sources of uncertainty
- Sensitivity studies supports identification of controls and compensatory measures to reduce risk
- Application of defense-in-depth and safety margin philosophies consistent with NRC guidance and policy 20
Next Steps Issue Commission Pre-application Receive NAC ACRS Full Paper Engagement Package Committee (Information) with NAC Application December 6, 2023 January 2024 First Quarter Fourth Quarter 2024 2024 Methodology approval needed by NAC in January 2024 21
References
- PNNL Methodology:
- Development and Demonstration of a Risk Assessment Approach for Approval of a Transportation Package of a Transportable Nuclear Power Plant for Domestic Highway Shipment (ML23268A331)
- Draft NRC Staff Evaluation:
- Development and Demonstration of a Risk Assessment Approach for Approval of a Transportation Package of a Transportable Nuclear Power Plant for Domestic Highway Shipment (ML23296A083) 22
Backup slides 23
Focus of Risk Method Supporting Project Pele Transportation 24
Overview of International and Domestic Regulations
- International Atomic Energy Agency (IAEA) transportation standards are developed by consensus by the TRANsportation Safety Standards Committee (TRANSSC)
- First standards published by the IAEA in 1961
- By 1969, many Member States adopted the standards as the basis for their own regulations, including the United States
- Applicable to domestic and international transport of radioactive material by all modes of transport
- Specific Safety Requirements No. SSR-6 (Rev. 1) provide standards for all package types, including Type B and fissile material 25
A Method to Define A Values
- Prior to the Q-System, radionuclides were:
- Categorized into seven transport groups and
- A "special form group
- Normalizes radioactivity based on radiation risk
- Establishes basic radiological quantity for transport
- A values delineate between Type A and Type B packages*
- A1 is for special form material
- A2 is for normal form material 26
Regulations and Guidance for Package Approval
- Advisory material is in IAEAs Specific Safety Guide No. 26 (SSG-26)
- Q-System was introduced in 1973 IAEA regulations (Annex 1, SSG-26).
- It determines the activity limits for each radioisotope (i.e.,
A1/A2 values)
- A Values were codified in NRC and DOT regulations in September 1983 (48 FR 35600 and 48 FR 10218, respectively) 27
Risk-informed Methodology Risk Evaluation Guidelines 28