ML20093L645
| ML20093L645 | |
| Person / Time | |
|---|---|
| Issue date: | 02/20/2020 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Widmayer, D, ACRS | |
| References | |
| NRC-0803 | |
| Download: ML20093L645 (267) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Future Plant Designs Subcommittee Docket Number: (n/a)
Location: Rockville, Maryland Date: Thursday, February 20, 2020 Work Order No.: NRC-0803 Pages 1-223 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
1 1
2 3
4 DISCLAIMER 5
6 7 UNITED STATES NUCLEAR REGULATORY COMMISSIONS 8 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 9
10 11 The contents of this transcript of the 12 proceeding of the United States Nuclear Regulatory 13 Commission Advisory Committee on Reactor Safeguards, 14 as reported herein, is a record of the discussions 15 recorded at the meeting.
16 17 This transcript has not been reviewed, 18 corrected, and edited, and it may contain 19 inaccuracies.
20 21 22 23 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 + + + + +
4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5 (ACRS) 6 + + + + +
7 FUTURE PLANT DESIGNS SUBCOMMITTEE 8 + + + + +
9 THURSDAY 10 FEBRUARY 20, 2020 11 + + + + +
12 ROCKVILLE, MARYLAND 13 + + + + +
14 The Subcommittee met at the Nuclear 15 Regulatory Commission, Two White Flint North, Room 16 T2D10, 11545 Rockville Pike, at 1:00 p.m., Dennis 17 Bley, Chair, presiding.
18 19 COMMITTEE MEMBERS:
20 DENNIS BLEY, Chair 21 RONALD G. BALLINGER, Member 22 CHARLES H. BROWN, JR., Member 23 VESNA B. DIMITRIJEVIC, Member 24 WALTER L. KIRCHNER, Member 25 JOSE MARCH-LEUBA, Member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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2 1 DAVID PETTI, Member 2 JOY L. REMPE, Member 3 PETER RICCARDELLA, Member 4 MATTHEW W. SUNSERI, Member 5
6 ACRS CONSULTANTS:
7 MICHAEL L. CORRADINI 8 STEPHEN SCHULTZ 9
10 DESIGNATED FEDERAL OFFICIAL:
11 DEREK WIDMAYER 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 C-O-N-T-E-N-T-S Opening Remarks - Dennis Bley . . . . . . . . . . 4 DG-1364 "Volcanic Hazards Assessment for Proposed New and Advanced Nuclear Power Reactor Sites" . . . . . . . . . . . . . . . . . 7 Adjourn . . . . . . . . . . . . . . . . . . . . 223 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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4 1 P R O C E E D I N G S 2 1:01 p.m.
3 CHAIR BLEY: Good afternoon. The meeting 4 will now come to order. This is a meeting of the 5 Advisory Committee on Reactor Safeguards, excuse me, 6 Subcommittee on Future Plant Designs. I'm Dennis 7 Bley, Chairman of the Subcommittee.
8 ACRS members in attendance are Joy Rempe, 9 Ron Ballinger, I think Charlie Brown will be back with 10 us, Walt Kirchner, Dave Petti is here, Vesna will be 11 back with us, Vesna Dimitrijevic. And I think Jose 12 March-Leuba will be back with us.
13 I forgot Matt. I've got him written on 14 the side here, Matt Sunseri, and Pete Riccardella, and 15 our consultant, Steve Schultz, and possibly our 16 consultant, Mike Corradini. I'm not sure if he'll be 17 here or not. Derek Widmayer of the ACRS staff is the 18 designated federal official for this meeting.
19 The purpose of today's meeting is to 20 discuss the draft Regulatory Guide 1364, Volcanic 21 Hazards Assessment for Proposed New and Advanced 22 Nuclear Power Reactor Sites.
23 As the NRC staff was preparing to review 24 and regulate this new generation of non-lightwater 25 reactors, it appeared that one of the developers might NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 1 site a reactor in an area of potential volcanic 2 activity.
3 While the staff has conducted reviews of 4 volcanic hazards for several existing facilities, 5 including one nuclear power plant, it has not issued 6 guidance on considering these hazards using a risk-7 informed methodology. That's what this reg guide is 8 proposing.
9 The subcommittee will gather information, 10 analyze relevant issues and facts, and formulate 11 proposed positions and actions as appropriate. This 12 matter may be presented to the subcommittee again 13 after the public comment period if decided by the 14 subcommittee consistent with the committee's reviews 15 of regulatory guides.
16 I lost my place. The ACRS was established 17 by statute and is governed by the Federal Advisory 18 Committee Act, FACA. The NRC implements FACA in 19 accordance with its regulations found in Title 10, the 20 Code of Federal Regulations, Part 7.
21 As a FACA committee, we can only speak 22 through our published letter reports. We hold 23 meetings to gather information and perform preparatory 24 work that will support our deliberations at a full 25 committee meeting.
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6 1 The rules for participation in all ACRS 2 meetings, including today's, were announced in the 3 Federal Register on June 13th, 2019. The ACRS section 4 of the US NRC public website provides our charter, by-5 laws, agendas, letter reports, and transcripts of full 6 and subcommittee meetings, including the slides 7 presented there.
8 The meeting notice and agenda for this 9 meeting were posted there. As stated in the Federal 10 Register notice, and in the in a public meeting notice 11 posted to the website, members of the public who 12 desire to provide written or oral input to the 13 subcommittee may do so and should contact the 14 designated federal official five days prior to the 15 meeting.
16 Today's meeting is open to public 17 attendance, and we have received no written statements 18 or requests to make an oral statement. We also set 19 aside ten minutes in the agenda for spontaneous 20 comments from members of the -- of the public who are 21 attending our meetings or listening to them.
22 Today's meeting is being held with a 23 telephone bridge line allowing participation of 24 members of the public over the phone. a transcript 25 of today's meeting is being kept. Participants in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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7 1 meeting should use the microphones located throughout 2 the room and speak with sufficient clarity and volume 3 so that they may be readily heard when they're 4 addressing the subcommittee.
5 At this time, I ask that the attendees in 6 the room please silence all their cell phones and 7 other noise makers. And I remind speakers at the 8 front table to turn on the microphone, the little 9 button nearest you will turn it on, when they're 10 speaking and to turn it off when you're not speaking.
11 But since we only have one presenter, it can stay on 12 all the time.
13 We will now proceed with the meeting, and 14 I call on Jenise Thompson of NRR to begin the 15 presentation.
16 Jenise?
17 MS. THOMPSON: Thank you. Good afternoon, 18 my name is Jenise Thompson. I'm a geologist in the 19 External Hazards Center of Expertise in NRR. And I'm 20 here today to present to you the details contained in 21 draft Guide 1364, the Volcanic Hazards Assessment for 22 Proposed New and Advanced Nuclear Power Reactor Sites.
23 This draft guide was the result of a staff 24 working group that met to determine the regulatory 25 need, decide on an optimal path forward, and then NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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8 1 finally to produce the technical content and process 2 that is in the draft guide that is before you today.
3 As stated in the title, this draft guide 4 applies to new and advance reactor sites or applicants 5 applying for a NRC license under their applicable 6 regulation.
7 CHAIR BLEY: The guide makes a specific 8 point of doing a guide for reactors, but I don't see 9 anything in the guide that wouldn't apply to other 10 facilities that might, had to do a volcanic 11 assessment.
12 MS. THOMPSON: And that is correct. So 13 there's nothing in the guide that would preclude a 14 perspective applicant for another type of application 15 to use this Volcanic Hazards Analysis approach for 16 another licensing activity or another application.
17 But for the time being, the staff and the working 18 group focused just on the reactor, because that was 19 the near term need.
20 MEMBER REMPE: So along those lines, I 21 know it's just at the end of the draft guide, it talks 22 about that just a few miles away, with alternative 23 sites, you might see a considerable difference in the 24 hazard associated or posed by volcanoes. So along 25 those lines, if they were to site a new or advanced NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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9 1 reactor near another reactor on a site that might not 2 be, well, anyway if they were to do that along another 3 site, do they have to consider co-located hazards in 4 this draft guide? Because I didn't see that notice.
5 And so it's like even though this new site 6 that's on a site, or this new plant that's on a site 7 might not pose a hazard, the volcano might hit another 8 facility, and that could cause a hazard. And has that 9 been considered in the approach or will it be?
10 MS. THOMPSON: I'm actually going to toss 11 that over to our volcanic hazards expert here, Britt.
12 MEMBER REMPE: Does the question make 13 sense, what I'm trying to ask, first of all? Because 14 I didn't say it as well as I could have.
15 MS. THOMPSON: Are you getting at, like, 16 a back fit, would a co-located nearby site have to 17 reassess their hazard based on what a new site would 18 have to do?
19 MEMBER REMPE: No, I'm putting a new 20 reactor on a site with other facilities. And as part 21 of that assessment, the volcanic flows would maybe go 22 by the co-located facilities where you might have a 23 hazard. So in addition to considering the new 24 location with the new facility, do they not need to do 25 sort of a back fit, but it's because it's co-located, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 1 is what I'm getting to.
2 MS. THOMPSON: So the intention of the 3 guide is not to impose a back fit on any of the 4 existing facilities. Because the draft guide that we 5 have developed we believe is consistent with the prior 6 licensing actions that the NRC staff have taken for 7 the current operating facilities. So I don't know if 8 anything ---
9 MEMBER DIMITRIJEVIC: Our concern is that 10 this can create additional hazard. Let's say that you 11 have a chemical factory with the lava, we can create 12 debris, can create some additional hazard.
13 MS. THOMPSON: Oh, so you're talking about 14 not just an NRC facility but ---
15 MEMBER DIMITRIJEVIC: Right.
16 MS. THOMPSON: -- any other facility --
17 MEMBER DIMITRIJEVIC: Which can create 18 additional concern.
19 MS. THOMPSON: -- located near the 20 proposed site.
21 MEMBER REMPE: That's true, it might not 22 just be a reactor. But my thought process, I'm 23 thinking of a large site with a lot of facilities.
24 And you might want to put a new facility, as indicated 25 in your upcoming slides, on that large site. And NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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11 1 there's a lot of other facilities there.
2 And, okay, so maybe you need to consider 3 those co-located facilities and the hazard posed by 4 the volcano for those other facilities in addition to 5 the new facility location.
6 I can get more explicit if we want to 7 talk, Idaho, for example, but there are a lot of other 8 facilities out there. And so maybe where the new 9 facility is is not so bad if you have a boundary. But 10 there's other facilities where the lava might flow and 11 could cause a problem.
12 MEMBER BROWN: But you're implying then, 13 that because you put this new facility there, the 14 other ones are going to have to back fit themselves 15 and --
16 MEMBER REMPE: No. I'm saying with the 17 new facility they need to consider more than the lava 18 flows from that facility. There might be other co-19 located hazards that they need to consider. And so 20 it's not really a back fit for the existing 21 facilities, but you need to consider where the lava --
22 CHAIR BLEY: I think I understand what 23 you're --
24 (Simultaneous speaking.)
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12 1 different way?
2 MEMBER REMPE: Okay.
3 CHAIR BLEY: Because I thought at first it 4 was thinking of a back fit. But if there's a hazard 5 nearby that could affect the new reactor that could be 6 activated by the volcano, then that knock-on effect 7 ought to be considered.
8 MEMBER BROWN: Lava stream effect, in 9 other words.
10 MEMBER REMPE: Yes. And I don't see that 11 in the guide. But because of the way this discussion 12 was going, I thought I'd bring it up now.
13 DR. CORRADINI: Well, particularly if it's 14 regulated or had been licensed by a different group.
15 MEMBER REMPE: Yes.
16 MR. MARSHALL: If I can, this is Jane 17 Marshall, NRR Deputy Director of Division of 18 Engineering and External Hazards. Nearby facilities 19 are considered in the EIS development, so they are 20 considered. We'll take it back and see if we can put 21 a note somewhere in the reg guide to flag your 22 particular concern. But nearby facilities, whether 23 they're chemical plants or other nuclear sites, are 24 considered as part of the EIS.
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13 1 probably weren't, well, it's interesting where it 2 shows up. Because if the volcanic activity can affect 3 them, and they in turn can affect the plant, other 4 sorts of things fall into that category that would be 5 picked up. So it kind of means when they do that 6 analysis they need to have this in mind as well. I 7 don't know where that --
8 MEMBER REMPE: An environmental impact 9 statement --
10 MEMBER KIRCHNER: More specifically --
11 MEMBER REMPE: -- may not address volcanic 12 hazards.
13 MEMBER KIRCHNER: -- for a while there was 14 consideration of high temperature reactors for 15 hydrogen production.
16 CHAIR BLEY: Yes, there was.
17 MEMBER KIRCHNER: And that would present 18 an interesting combination from an external hazards 19 standpoint.
20 MEMBER PETTI: Because I think the 21 question really is how nearby is nearby? The Idaho 22 site is quite large. If they wanted to site 40 miles 23 from their reactor, that doesn't sound nearby to me.
24 CHAIR BLEY: Well, you're going to hear 25 more about how far away is nearby.
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14 1 MEMBER PETTI: Yes, right.
2 MEMBER BROWN: And I'm still trying to 3 understand Joy's comment. In other words, I put a new 4 reactor in. This is a lot larger site with other 5 facilities on the site.
6 DR. CORRADINI: You want to get specific?
7 I know what she's going at.
8 MEMBER BROWN: Well, but her comment was 9 other volcanic hazards. She just made that statement.
10 MEMBER REMPE: A volcano comes by, it hits 11 the new reactor, okay. And also, maybe it misses the 12 new reactor, because it's up high. Oh, I'm sorry, I 13 didn't have my mic on. Maybe the new reactor site is 14 up high. But the volcanic flow goes to the site, hits 15 another facility.
16 MEMBER BROWN: You're talking about it 17 becomes now a hazard for the reactor plant because it 18 wasn't before because of its distance. But now, 19 because of the volcano, and whatever it does to it, 20 now it becomes a hazard to the new one.
21 MEMBER REMPE: To the new facility.
22 MEMBER BROWN: That's what I was trying to 23 get at, what she was driving at.
24 MEMBER REMPE: Sorry, I wasn't very clear 25 on what I asked.
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15 1 (Simultaneous speaking.)
2 MEMBER REMPE: But I think the discussions 3 made my point clear.
4 MS. THOMPSON: Yes, and I've made a note 5 to look at that, as you called it, the knock on, you 6 know, kind of that domino effect of hazards. So I'll 7 make a note and take that back to the working group.
8 MEMBER REMPE: Thank you.
9 MS. THOMPSON: You're welcome. So today, 10 the presentation will give you a background of how the 11 staff assessed the regulatory need and determined that 12 developing a reg guide was the optimal path forward.
13 This was accomplished through the performance of a 14 regulatory analysis which I will share with you.
15 I will then provide you an overview of 16 volcanic hazards and some of the unique demands that 17 they may place on a nuclear power reactor. I will 18 then discuss the proposed approach in the draft guide 19 to perform the Volcanic Hazards Analysis or VHA.
20 I will discuss the harmonization of this 21 draft guide with the existing international guidance 22 document that is available with respect to volcanic 23 hazards. And then I'll share with you our next steps 24 and timeline for completion.
25 CHAIR BLEY: I hope we can pronounce that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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16 1 acronym?
2 MEMBER BROWN: Which one?
3 CHAIR BLEY: VHA, ha, ha, ha.
4 MS. THOMPSON: So the staff working group 5 consists of staff.
6 MEMBER BROWN: Could I ask you one more 7 before you ---
8 MS. THOMPSON: Of course.
9 MEMBER BROWN: Obviously, we've been 10 building plants since the '60s.
11 DR. CORRADINI: Not long enough.
12 MEMBER BROWN: Well, we'll debate that, 13 obviously. At least two of them were being built.
14 And this is a new reg guide, and it doesn't sound like 15 anybody worried about volcanos for the last 60 years.
16 CHAIR BLEY: You weren't listening when we 17 --- oh, you weren't here when we ---
18 MEMBER BROWN: I wasn't here.
19 CHAIR BLEY: Ha, ha, ha.
20 MEMBER BROWN: I was in the ---
21 CHAIR BLEY: Are you going to talk about 22 that?
23 MS. THOMPSON: I am. It's going to come 24 up.
25 MEMBER BROWN: About why we need one now.
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17 1 MS. THOMPSON: Yes. So I will ---
2 (Simultaneous speaking.)
3 MS. THOMPSON: -- in just a few slides, I 4 will discuss why the working group made the decision 5 to assess the regulatory need and decide whether or 6 not action needed to be taken. I will give you a 7 summary of the ---
8 MEMBER BROWN: We'll get to background in 9 a little ---
10 MS. THOMPSON: We'll get there, yes.
11 MEMBER BROWN: Why we're doing a new 12 regulation.
13 MS. THOMPSON: I think it's on the next 14 slide actually, they why.
15 MEMBER KIRCHNER: Jenise, just along those 16 lines, since you already did it, actually, the NRC for 17 the Columbia plant, so will this be in the spirit of 18 other actions that the Agency is taking, technology 19 neutral?
20 Where I'm going with this is I don't know 21 why you're labeling it for advanced nuclear power 22 reactor sites.
23 MS. THOMPSON: That was the discussion 24 that the working group went back and forth on for a 25 fair amount of time, discussing whether the draft NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 1 guide should apply to any nuclear facility or just 2 focus on reactors for the time being.
3 MEMBER KIRCHNER: No, I'm keying on the 4 word advanced.
5 MS. THOMPSON: Advanced.
6 MEMBER KIRCHNER: Because I would think 7 this is a perfect candidate for technology neutral 8 regulation, not something that just gets a carve out 9 for new advanced plants. So I'm objecting to the 10 title.
11 MS. THOMPSON: You're objecting to ---
12 MEMBER KIRCHNER: But I've looked through 13 it. I didn't see anything, in my opinion, that made 14 it specific for advanced reactors.
15 DR. CORRADINI: If a new light water 16 reactor were to appear somewhere in the zone of 17 interest, does this apply? That's another way of 18 asking the question.
19 MS. THOMPSON: Yes. Because it would be 20 considered a new reactor. We specifically included 21 advanced reactors, because in some discussions saying 22 a new reactor seems to imply a light water reactor.
23 So new and advanced we felt adequately captured any of 24 the potential applicants for a Part 50 or Part 52 25 license that we may anticipate in the future.
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19 1 MEMBER KIRCHNER: Yes. I just would seem 2 to me that I'm quibbling on the margin --
3 MS. THOMPSON: Okay.
4 MEMBER KIRCHNER: -- if you'll bear with 5 me. But I would just strike --
6 MS. THOMPSON: Strike advanced?
7 MEMBER KIRCHNER: -- new and advanced.
8 It's new sites that you're really --
9 MS. THOMPSON: Correct.
10 MEMBER KIRCHNER: -- thinking about, not 11 the reactor technology. It's for reactors, obviously.
12 CHAIR BLEY: Well, even that, you guys are 13 convincing me we ought to wait until everybody's back 14 before we start a session.
15 (Laughter.)
16 CHAIR BLEY: This could apply to any 17 nuclear facility.
18 MEMBER KIRCHNER: Yes, that's what I was 19 thinking.
20 CHAIR BLEY: Could, they've written it to 21 apply to reactors.
22 MEMBER KIRCHNER: Yes, but example, it 23 should work for a fuel fabrication facility.
24 MS. THOMPSON: Correct.
25 MEMBER KIRCHNER: It could work for a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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20 1 medical isotope facility.
2 MS. THOMPSON: Yes.
3 MEMBER KIRCHNER: So again, that's just a 4 top level comment.
5 MS. THOMPSON: And the working group 6 actually had many conversations that sounded just like 7 this about whether we should include this to include 8 everything, especially because that IAEA Guide that I 9 will discuss later is designed for the full spectrum 10 of nuclear facilities. So that was something that the 11 working group did consider.
12 DR. CORRADINI: So let me ask now, a 13 quick, oh, I'm sorry.
14 MEMBER DIMITRIJEVIC: Sure, you started so 15 --
16 DR. CORRADINI: No, no, you first.
17 MEMBER DIMITRIJEVIC: Oh, ladies, all 18 right. Jenise, I'm sort of curious about the 19 structure of your team. Is it mostly geologists, have 20 you got a PRA expert, the seismic content, or what ---
21 MS. THOMPSON: That's the next thing I was 22 going to get to.
23 MEMBER DIMITRIJEVIC: Oh, okay. All 24 right.
25 DR. CORRADINI: So my question is, is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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21 1 there any other technology that has to worry about 2 volcanoes?
3 MS. THOMPSON: By technology, that's 4 regulated by the ---
5 DR. CORRADINI: Any sort of manmade 6 technology in the United States that has to worry 7 about volcanoes other than nuclear?
8 MS. THOMPSON: I would say that any 9 facility sited near a place where volcanic hazards may 10 impact your facility, they should be considered. I 11 think a great example is a new high school built in 12 Hawaii. I think that should consider ---
13 DR. CORRADINI: But I'm asking, I know 14 what should be, I'm asking are they? I don't think 15 chemical facilities are.
16 MS. THOMPSON: I would have to look that 17 up unless, Britt, do you, this is Dr. Brittain Hill.
18 He's the consultant to the staff.
19 DR. HILL: Brittain Hill, NRC consultant.
20 There are a number of facilities around the United 21 States that take into account the potential for 22 volcanic hazards. Jenise was mentioning certainly in 23 Hawaii, a geothermal power plant is located in the 24 East Rift, has active lava flow mitigation to it.
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22 1 debris flow remediation all around the suburbs east of 2 the Olympic Sound, Puget Sound.
3 DR. CORRADINI: Is this ---
4 DR. HILL: Many ---
5 DR. CORRADINI: -- state regulated or is 6 it federal?
7 DR. HILL: -- facilities though are not 8 built in areas of potentially active volcanism.
9 DR. CORRADINI: Okay.
10 MEMBER REMPE: But I think Mike's question 11 was different. Does another agency require those 12 facilities to consider, does the EPA require it, does 13 the state require that they consider volcanic 14 activity?
15 DR. CORRADINI: I understand it might be 16 prudent, but I'm just trying to decide is it a federal 17 mandate, is it a state mandate, is it, I was going to 18 use the word arbitrary, but that's not the word I'm 19 looking for.
20 PARTICIPANT: Local.
21 DR. CORRADINI: Local, thank you very 22 much, a local requirement. That's where I was going.
23 Because I was going to think of chemical plants. But 24 I see some of your examples. But are those examples 25 coming out because it's a federal requirement? Or is NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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23 1 it a state requirement? Or is it a locale?
2 DR. HILL: I'm not aware of an overarching 3 federal requirement to explicitly address volcanic 4 hazards in planning.
5 DR. CORRADINI: I didn't think so.
6 DR. HILL: That usually is left at the 7 state level.
8 DR. CORRADINI: Okay.
9 DR. HILL: I know there is guidance at the 10 state level in, for example, Oregon, about potential 11 volcanic hazards. But I'm not aware if it has any 12 statutory authority behind it.
13 DR. CORRADINI: Okay. All right, thank 14 you.
15 MEMBER DIMITRIJEVIC: Well, this could be, 16 I mean, those questions could be really relevant when 17 we are discussing mitigating measures to divert the 18 lava. Because you cannot just run a mitigating 19 measure to build these lava diverters. You have to 20 watch out where you're diverting them if there is a 21 state regulation of it.
22 MS. THOMPSON: Yes. So to get back to 23 your question about the composition of the working 24 group, the working group is composed of numerous 25 technical and project management staff from NMSS and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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24 1 from NRR.
2 Within NRR, the staff on the working group 3 come from the Divisions of New and Renewed Licenses 4 from Advanced Reactors and Non-power Production and 5 Utilization Facilities, and the Division of 6 Engineering and External Hazards.
7 We also have research involved as the 8 project management support for the draft guide and, as 9 I previously mentioned, we have contracted with the 10 Center for Nuclear Waste Regulatory Analyses to obtain 11 the consultation services of Dr. Hill here as an 12 expert volcanologist consulting the staff.
13 MEMBER DIMITRIJEVIC: Do you have a PRA 14 expert?
15 MS. THOMPSON: We do not have a PRA expert 16 on the working group.
17 So I think there was another question of 18 why did we pursue this action now. Oh, okay, sorry, 19 two different screens showing me two different things.
20 So the working group was formed based in 21 response to several factors. Most notably was that 22 recently Congress funded the Department of Energy 23 through the Nuclear Energy Innovation and Capabilities 24 Act of 2017 to develop advanced reactor projects at 25 the National Laboratory sites.
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25 1 The Idaho National Laboratory site was 2 selected by the Department of Energy for the home of 3 the National Reactor Innovation Center which has 4 recently opened and was funded in this fiscal year.
5 DOE is also authorized, under the Atomic Energy Act, 6 to build and operate nuclear reactors which the NRC 7 has the licensing authority over.
8 DR. CORRADINI: If I might just ask.
9 MS. THOMPSON: Okay.
10 DR. CORRADINI: Historically, Idaho had 11 what is called the Test Station. And on the Test 12 Station was ATR, SL1, et cetera, et cetera, et cetera.
13 Were those all state regulated in terms of any sort of 14 this activity? Or it was just never recognized that, 15 because it was DOE orders that regulated the 16 facilities, that this was never considered before for 17 those facilities?
18 MS. THOMPSON: When you say this, do you 19 mean volcanic hazards?
20 DR. CORRADINI: Yes.
21 DR. HILL: Brittain Hill, NRC consultant.
22 Idaho National Environmental Engineering Lab, as it 23 used to be called, had an active program of volc 24 hazards analysis since about 1990. It's undergone 25 several major revisions since then. So volcanic NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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26 1 hazards in INL --
2 DR. CORRADINI: Does exist.
3 DR. HILL: -- have been well recognized by 4 the DOE and associated entities.
5 DR. CORRADINI: Okay.
6 MEMBER REMPE: So along that line of 7 questioning, I'm interested in exploring what's going 8 on with DOE and NRC, if there's an MOU, and if this 9 guidance might be passed on to DOE, and they might 10 want to adopt it as part of their orders.
11 Because in addition to the existing 12 facilities, my understanding is DOE's interested in 13 authorizing the start-up of the VTR. And it's a new 14 facility that would be a test reactor. And would they 15 apply this guidance with it? Or would they use this 16 since 1990 guidance that they have?
17 DR. HILL: Brittain Hill, the 1990 onward 18 was more the Volcanic Hazards Analysis. It wasn't 19 guidance.
20 MEMBER REMPE: Yes.
21 DR. HILL: The application of the Volcanic 22 Hazards Analysis to safety decisions would occur 23 through DOE's internal standard, STD 1020, which was 24 most recently revised. It has its own criteria for 25 what would be an acceptable volcanic analysis for DOE NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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27 1 regulated facilities.
2 MEMBER REMPE: And how does that compare 3 with what's in your guidance? Is it more limiting, or 4 less limiting, or do you know?
5 DR. HILL: It's hard to draw a direct 6 comparison. In many of the areas that we are focusing 7 in a bit more detail, the DOE analyses really are 8 focused more on design basis development rather than 9 siting decisions.
10 MEMBER REMPE: Okay.
11 DR. HILL: I think we have a more risk-12 informed performance based framework to implement a 13 variety of safety decisions more openly.
14 MEMBER REMPE: Thank you.
15 MS. THOMPSON: So the NRC and the 16 Department of Energy have both recognized that there 17 are volcanic hazards at the INL site. Additionally, 18 the staff also considered that there are other areas 19 of the United States, that may be considered at some 20 time in the future for a new reactor site, that may 21 also have the presence of known or potential volcanic 22 hazards that would need to be assessed in the site 23 characterization for that new reactor application.
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28 1 within the Idaho National Laboratory area.
2 Additionally, the NRC has regulatory 3 requirements for site characterization, one of which 4 specifically calls out volcanic activity. But we do 5 not have specific guidance on how to assess those 6 volcanic hazards and what an acceptable approach would 7 look like for a Volcanic Hazards Assessment.
8 Those regulatory requirements are shown 9 here. I'm actually going to rely on my notes and read 10 these off so that I get the exact quotes correct. For 11 Part 52, General Design Criterion 2 states that 12 structures, systems, and components important to 13 safety shall be designed to withstand the effects of 14 natural phenomenon without loss of capability to 15 perform their safety functions.
16 Those S.C. design bases should reflect 17 appropriate consideration of the most severe of the 18 natural phenomena that have historically been reported 19 for the site and surrounding area with sufficient 20 margin for the limited accuracy, quantity, and period 21 of time in which the historical data have been 22 accumulated.
23 This language is then echoed in Part 52 24 for both an Early Site Permit application and Part 25 5279 for a combined license application. And within NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 1 this characterization, a severe natural phenomena 2 would include something like volcanic hazards.
3 And then finally, the only specific 4 mention of volcanic activity within the siting 5 regulations for reactors is in Part 100.23, Reactor 6 Site Criteria, which states that each applicant shall 7 investigate all geologic and seismic factors, for 8 example, volcanic activity, that may affect the design 9 and operation of the proposed nuclear power plant, 10 irrespective of whether such factors are explicitly 11 included in this section.
12 So despite the specific inclusion of 13 volcanic hazards within our regulatory requirement, we 14 don't have guidance. But the staff has undertaken 15 several reviews in the past on an ad hoc basis for 16 sites that did consider volcanic hazards.
17 These prior reviews or licensing actions 18 are shown here on the figure in yellow. There are six 19 prior licensing actions that on some level considered 20 volcanic hazards. The reviews for these sites 21 included facilities that ranged from nuclear power 22 reactors, spent fuel storage, enrichment facility, and 23 nuclear waste.
24 These sites in yellow, you'll notice they 25 are only four, although there were six reviews, that's NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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30 1 because three of the reviews were conducted for 2 facilities at the INL location, two for independent 3 spent fuel storage installation and one for an 4 enrichment facility.
5 The blue pin toward the top shows you the 6 location of Mt. St. Helens, which last erupted in 1980 7 and, as you can see, is located between the only two 8 reactors that were sited in the United States that 9 considered volcanic hazards.
10 MEMBER DIMITRIJEVIC: Well, how about the 11 ash ---
12 MS. THOMPSON: Yes, I'm going to --- so 13 the Columbia site is located 217 kilometers east of 14 Mt. Helens which, as I said, last erupted in 1980. At 15 the time of licensing, the Columbia plant considered 16 a design and operational basis volcanic event for 17 volcanic ash fall. And Columbia is the only operating 18 reactor that has a design basis for a volcanic event.
19 The staff's conclusions for the Columbia 20 site were based on a demonstration of the plant's 21 ability to withstand the wet and dry loads of 22 potential ash fall deposits at the site, operational 23 considerations for mitigating the effects of ash fall 24 on plant structures, systems, and components, and the 25 installation of oil bath air filters, excuse me, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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31 1 during an ash fall event. And this represents the 2 last time that the staff conducted a review for 3 volcanic hazards at a reactor site.
4 MEMBER KIRCHNER: For the record, those 5 were the emergency diesel generators, aren't 6 they?
7 MS. THOMPSON: Yes.
8 MEMBER KIRCHNER: Okay 9 DR. CORRADINI: That was the, I guess 10 Walt is more familiar, those were the only active 11 changes to the plant design is, essentially, the 12 air filtration going into the diesel generators, 13 or were there other things besides that?
14 MS. THOMPSON: I know of the air filters 15 for the diesel generators. And, Britt, did you want 16 to expand on that?
17 DR. HILL: This is Brittain Hill. There 18 are some operational considerations for ash removal 19 from, say in the electric switchyard, enhanced 20 maintenance cycles on some of the other air filtration 21 systems.
22 DR. CORRADINI: So it would be operator 23 actions?
24 DR. HILL: Operation actions, yes, sir.
25 DR. CORRADINI: Okay.
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32 1 MEMBER DIMITRIJEVIC: How about control 2 room, control room air filters.
3 MS. THOMPSON: The control air filters?
4 MEMBER DIMITRIJEVIC: And then also, if 5 there is operator action --
6 PARTICIPANT: Green light on.
7 MEMBER DIMITRIJEVIC: -- we can pursue 8 many LOCA operator actions --
9 MS. THOMPSON: I don't have anything on 10 the control room in my notes.
11 MEMBER DIMITRIJEVIC: I know, I know.
12 (Simultaneous speaking.)
13 MS. THOMPSON: But I can take that back to 14 look into it.
15 MEMBER DIMITRIJEVIC: We're not expecting 16 answers. I think the operator action is the one 17 thing, that's why I asked you do you have PRA people.
18 Because then you will know about the crucial --
19 MS. THOMPSON: And looking at the Columbia 20 mitigation actions and the procedures that would be 21 implemented in the warning time is something that the 22 staff considered in the VHA approach, which I'll 23 discuss later when I get to the mitigation action 24 stuff within the VHA approach outlined in the draft 25 guide. So we're coming back to Columbia and the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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33 1 actions taken there.
2 The Trojan site is or was located 55 3 kilometers southwest of Mount St. Helens. At the time 4 of licensing, both ash fall and debris flow from the 5 Cascade volcanoes were considered.
6 At the time of licensing, the potential 7 effects of these future volcanic hazards were 8 determined to have an insignificant effect on the 9 design and operation of the facility because of the 10 low frequency of occurrence and the characteristics of 11 the potential phenomena expected at the site as a 12 result of a volcanic eruption.
13 Following the 1980 eruption of Mount St.
14 Helens, a debris flow in-filled the Columbia River 15 channel downstream of the Trojan intake valve and 16 several millimeters of ash were deposited at the 17 facility. Following this eruption and the receiving 18 of these volcanic hazards close to the Trojan site, 19 the hazards were re-evaluated based on the 1980 20 eruption characteristics, but no changes were made to 21 the design basis, excuse me, the plant operating 22 basis.
23 CHAIR BLEY: That's interesting. There 24 was minimal ash fall there.
25 MS. THOMPSON: Yes.
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34 1 CHAIR BLEY: There was minimal ash fall 2 around Pasco and Richland, but further east, I think 3 beyond Columbia Station, there were several feet of 4 ash fall out that far.
5 MS. THOMPSON: There were favorable winds, 6 or Britt can explain it.
7 CHAIR BLEY: Yes, there were.
8 MS. THOMPSON: Essentially that's what it 9 comes down to. But, Britt, did you want to add 10 anything to that?
11 DR. HILL: Yes, Brittain Hill. The 1980 12 eruptions at St. Helens, there was really only one 13 day, I believe it was June 3rd, where the ash plume 14 was directed to the southwest towards Portland and the 15 Trojan Power Plant. All the other eruptions, the main 16 eruption of May 18th, it all went out to the east.
17 And so you were getting tens of centimeters, to almost 18 100 centimeters in some locations, of that ash fall 19 during the main event.
20 The volcanic hazards before that eruption 21 really didn't consider large volume debris flows 22 either. And of course, with the collapse of the north 23 face of Mount St. Helens, a huge amount of material 24 and debris was thrown into river drainage which ended 25 up at the Tootle River flowing into the Columbia and, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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35 1 because of a combination of density and tidal effects, 2 traveled about nine miles upstream from the entrance 3 of the Tootle River into the Columbia.
4 But that debris was confined to the 5 central part of the Columbia River channel, whereas 6 the Trojan intakes were up towards the bank. So the 7 debris from the 1980 eruption didn't actually get 8 taken in to the intakes for the Trojan Water System.
9 Trojan was offline at the time for refueling during 10 the 1980 eruption.
11 MS. THOMPSON: And Trojan was 12 decommissioned in 1992.
13 The Idaho National site, as I mentioned 14 before, was subject to three different prior reviews 15 by the NRC staff. Two of these were for the TMI2 and 16 the Idaho spent fuel facility ISFSIs. And the third 17 review was conducted for the Eagle Rock enrichment 18 facility.
19 At the INL site, the staff determined that 20 lava flows and ash fall hazards were the primary 21 volcanic hazards under consideration.
22 MEMBER DIMITRIJEVIC: How far is the 23 volcano?
24 MS. THOMPSON: I'm sorry?
25 MEMBER DIMITRIJEVIC: How far is it from NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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36 1 the volcano?
2 MS. THOMPSON: Oh, for INL, I don't have 3 --
4 MEMBER DIMITRIJEVIC: So Columbia is ---
5 (Simultaneous speaking.)
6 MS. THOMPSON: So Columbia's 200 7 kilometers, so INL is somewhere between, I would say, 8 depending on where you are on the site, yes, probably 9 600, 700.
10 DR. CORRADINI: It was a different 11 potential volcano.
12 MS. THOMPSON: Yes.
13 DR. CORRADINI: It's not the same one.
14 MEMBER BROWN: It's not the same, I mean, 15 there are lava flows all around ---
16 (Simultaneous speaking.)
17 MS. THOMPSON: I was going to say, to 18 clarify, the ash fall hazard considered at the INL 19 site was looking at the Cascade volcanoes and ash from 20 an eruption there reaching the INL site. The lava 21 flow hazard is sourced in the eastern Snake River 22 Plain where the INL site is physically located. So 23 it's two hazards from two different sources that were 24 considered at the time of licensing ---
25 DR. CORRADINI: Thank you.
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37 1 MS. THOMPSON: -- for the INL site. And 2 the acceptability of these volcanic hazards at the INL 3 site was demonstrated at the time of licensing from 4 the appropriate design and operational bases for ash 5 fall, again from these further located volcanoes, the 6 low likelihood of lava flow inundation from lava flows 7 on the eastern Snake River Plain, and confidence in 8 the licensee's ability to divert potential lava flow.
9 MEMBER REMPE: I have a dumb question just 10 counting. I know about the TMI S.C. in Idaho. I know 11 about the proposed Eagle Rock facility. You said 12 there's a third facility, the Idaho spent fuel 13 facility. What is that?
14 MS. THOMPSON: Yes, so this was a proposed 15 ISFSI that was, an application was submitted, but the 16 facility was never built.
17 MEMBER REMPE: Okay, so there's only one 18 that's there, and the other two are ---
19 (Simultaneous speaking.)
20 MS. THOMPSON: Yes, so the review was 21 conducted.
22 MEMBER REMPE: Okay.
23 MS. THOMPSON: The review considered 24 volcanic hazards, and the working group considered any 25 review that was conducted, whether or not the outcome NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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38 1 was a constructed facility.
2 MEMBER REMPE: Thank you.
3 MEMBER DIMITRIJEVIC: May I ask why didn't 4 you, on Page 6, identify it as a volcano?
5 CHAIR BLEY: You need your green light on, 6 Vesna.
7 MEMBER DIMITRIJEVIC: Green light on. Now 8 I see. Why didn't you, on Page 6, identify all other 9 volcanoes considered?
10 MS. THOMPSON: The key consideration in 11 that is that the Mount St. Helens location is 12 essentially a point source of one volcano. The 13 eastern Snake River Plain is an area over which there 14 have been numerous flows in geologic history. So I 15 don't have a pointer, but I could point it out if you 16 wanted me to go back and do that.
17 MEMBER DIMITRIJEVIC: No, that's all 18 right. I was just thinking that the feature will be 19 better if you sort of identify all other hazards ---
20 CHAIR BLEY: Well, and there are other 21 Cascade mountains up there that are potential sites.
22 They're just showing us ---
23 MS. THOMPSON: We were trying to focus on 24 roughly where things were, and particularly Mount St.
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39 1 affect two reactor facilities. And I see that Britt 2 has something to add.
3 DR. HILL: I was just going to point out 4 there are about 500 volcanic eruptions in the eastern 5 Snake River Plain for the last 500,000 years. So 6 there are many, many dots that would kind of clutter 7 up the map for all of that.
8 MEMBER DIMITRIJEVIC: I just want to say 9 when we go through your guide, we will see that they 10 are required to identify the range of the hazards.
11 MS. THOMPSON: Yes, and ---
12 MEMBER DIMITRIJEVIC: And without those 13 500 dots, they will not be able to do this.
14 MS. THOMPSON: And we'll get to the range 15 of the hazards to be considered. And something that 16 I did look up anticipating a question like that is 17 that, according to the United States Geologic Hazards 18 Monitoring Program, there are 169 active volcanoes 19 capable of producing a wide range of hazards within 20 the United States alone. So not wanting to ---
21 (Simultaneous speaking.)
22 MS. THOMPSON: One hundred and sixty-nine.
23 So not wanting to cloud the figure any more than we 24 already had, we went with Mount St. Helens as the most 25 relevant to the discussion of volcanic hazards NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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40 1 affecting a nuclear reactor.
2 CHAIR BLEY: Jenise, since Yucca Mountain 3 is showing up here, during the ASLB hearings on Yucca 4 there were a number of contentions filed with respect 5 to volcanism. And 25 of them were deemed admissible 6 contentions.
7 I know DOE responded to them. I'm not 8 sure if staff reached the point they responded. And 9 I don't think they were ever resolved by the ASLB.
10 They're still dangling there. Did you consider those?
11 Are any of those having any impact on the information 12 you're identifying for applicant's to use in this reg 13 guide?
14 MS. THOMPSON: So I see Britt standing at 15 the microphone.
16 CHAIR BLEY: I bet he is.
17 DR. HILL: Brittain Hill, NRC consultant.
18 In a former life I was the senior level advisor for 19 Repository Science. One of my principle areas of 20 responsibility was the Yucca Mountain Safety Analysis 21 proposed closure. I can say quite confidently that 22 none of those issues have been adjudicated by the 23 Atomic Safety and Licensing Board.
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41 1 hazards with full knowledge of the content of those 2 technical objections or contentions.
3 CHAIR BLEY: Thank you.
4 MS. THOMPSON: And that's a perfect bridge 5 to the discussion of Yucca Mountain that the working 6 group considered in the guide.
7 CHAIR BLEY: But my question wasn't what's 8 the status of it. I kind of knew that. My question 9 was did any of the underlying technical issues raised 10 in those contentions find its way into the reg guide?
11 DR. HILL: Brittain Hill, consultant. The 12 short and simple answer is no.
13 MS. THOMPSON: The working group was 14 primarily focused on prior NRC staff review actions.
15 So that was the focus of our background gathering of 16 these prior licensing reviews to inform the draft 17 guide for future licensing reviews.
18 So for Yucca Mountain, the staff 19 considered two periods, the pre-closure or operational 20 period, and the post-closure period. For the 21 operational period, the occurrence of a new volcano 22 was screened out for the operational period. And it 23 was determined by the staff that ash fall could be 24 mitigated.
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42 1 what's the pre-closure period.
2 MS. THOMPSON: So the pre-closure period 3 is when the --
4 DR. CORRADINI: No, I know what it is, but 5 what's the time window? That's what I was --
6 MS. THOMPSON: Oh, the time window. Okay.
7 DR. CORRADINI: Is it 300? I was thinking 8 100 years.
9 MEMBER KIRCHNER: If my memory serves me 10 well, it's 300 years. But anyway, it's --- Mike, 11 what?
12 DR. CORRADINI: No, no, that's fine.
13 MEMBER KIRCHNER: It's 100 to 300. It was 14 when the hot fission products, the strontium and all 15 those dissipated their heat before closing. So 16 obviously --
17 DR. CORRADINI: It's when it was 18 ventilated.
19 MEMBER KIRCHNER: -- the long timeframe 20 was the actinides.
21 MEMBER REMPE: In all these, I've never 22 seen one of these studies, and I'm just curious on how 23 you decide that it's a negligible amount of 24 consequences or increased in risk. Is it 25 quantitative?
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43 1 You can say, well, the frequency is less 2 than ten to the minus 13, so we don't care. And well, 3 if there's one that's within ten to the minus four 4 that might occur, do you look at the consequences and 5 say the increase in source term is less than whatever, 6 or how do you go?
7 MS. THOMPSON: So there were three key 8 components to the conclusions for Yucca Mountain that 9 were made by the staff. And those were based on a low 10 likelihood of a volcanic event occurring. I don't 11 have if there was a number, but it was determined to 12 be sufficiently low.
13 The second component was that the amount 14 of high level waste, at least for the post-closure 15 period where the occurrence of a new volcano was 16 considered as the primary volcanic hazard, the high 17 level waste that would be entrained or ejected during 18 that new volcano would be sufficiently small.
19 And then the third component was that the 20 combination of natural and engineered barriers would 21 be sufficient in the occurrence of a new volcano to 22 limit the radio nuclide release. So it was a three-23 part conclusion. I don't have what those thresholds 24 were. But those were that ---
25 (Simultaneous speaking.)
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44 1 CHAIR BLEY: That's for Yucca, but if I 2 might, if any of our questions are going to be 3 answered later in your slides, ask us to wait.
4 MS. THOMPSON: Well, that one was right 5 there on this slide.
6 MEMBER REMPE: Okay. Well, in the case of 7 the reactors, I'm wondering if you ever got to where 8 you got quantitative and said that ---
9 (Simultaneous speaking.)
10 MS. THOMPSON: So the process which I will 11 get to and discuss, it allows there to be a 12 demonstration that you have reached a sufficiently low 13 risk at numerous steps in the process where you can 14 complete your analysis and be done.
15 (Simultaneous speaking.)
16 MEMBER REMPE: But I'm asking in the past, 17 like for Columbia and Trojan. Did you just follow 18 this process, or did you actually do some sort of 19 quantification and say it's less than a curie that 20 gets out or something like that, or a millicurie. Did 21 they go that far in the evaluations?
22 MS. THOMPSON: I'm going --
23 DR. HILL: Brittain Hill, I can speak to 24 Yucca Mountain which had a full blown probabilistic 25 risk assessment, it was called the Total Systems NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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45 1 Performance Assessment, that considered both the 2 likelihood of events, and the consequences, and 3 associated radiological doses into the accessible 4 environment.
5 In the post-closure period, the two-6 leading sources of risk were disruption by volcanoes 7 and by earthquakes. But even when you factored in the 8 amount released and the likelihood and timing of that 9 release, the release levels were less than one 10 millirem per year. The standard for Yucca Mountain 11 was 15 millirems a year. So these were quantified.
12 MEMBER REMPE: So that's good for Yucca 13 Mountain. I'm just curious about the --
14 MEMBER KIRCHNER: The siting of the other 15 two sites pre-dated PRA.
16 MEMBER REMPE: Yes, but they probably 17 didn't go into that level.
18 MS. THOMPSON: And the working group did 19 not consider that, whether there was a bounding number 20 that the applicant got to that the staff determined 21 was sufficient.
22 MEMBER REMPE: Thank you.
23 MS. THOMPSON: So considering all of the 24 prior licensing reviews, the staff wondered whether 25 this past approach of performing an ad hoc review was NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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46 1 sufficient and was adequately reflective of the NRC's 2 principles of good regulation, of openness, 3 sufficiency, independence, clarity, and reliability.
4 So to answer this and other questions, the 5 working group performed a regulatory analysis to 6 consider five different alternatives to both assess 7 the regulatory needs and determine the optimal path 8 forward.
9 The regulatory analysis, these five 10 different alternatives considered were to take no 11 action or, in other words, to keep doing these ad hoc 12 reviews as sites came in that needed to consider 13 volcanic hazards, to develop and issue guidance, to 14 endorse the existing IAEA safety guide which I will 15 discuss later in the harmonization section, to wait, 16 review, and consider for endorsement the development 17 of a consensus standard that is ongoing, and finally 18 to review and approve for use a topical report 19 submitted by an applicant.
20 To date, no applicant has indicated their 21 intention to submit a topical report. We just 22 included that as one of the possibilities that could 23 happen.
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47 1 content, control of the document as additional 2 factors, as well as the principles of good regulation 3 and risk-informed decision making in determining which 4 would be the optimal path forward. Following this 5 regulatory ---
6 DR. SCHULTZ: What was the fifth?
7 MS. THOMPSON: The fifth option was to 8 develop, or excuse me, to review and approve for use 9 a topical report submitted by an applicant. But no 10 applicant has submitted a ---
11 DR. SCHULTZ: No, I thought that was ---
12 MS. THOMPSON: -- a topical report or 13 indicated their intention to do so. We just included 14 it for the sake of considering every available 15 alternative that could happen.
16 The optimal path forward as determined by 17 the working group was to develop a regulatory guide.
18 Part of the reason for this is that not only does it 19 fit the schedule that we have outlined for ourselves, 20 it allows us to harmonize or draft guide with the 21 existing IAEA safety guide. It provides a mechanism 22 by which the staff can consider in the future any 23 consensus standard that becomes available for a 24 volcanic hazard assessment. And it also provides us 25 with multiple opportunities to interact with the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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48 1 public and external stakeholders on both the content 2 of the guide and how the guide is working.
3 DR. CORRADINI: If I might just ask --
4 MS. THOMPSON: Yes.
5 DR. CORRADINI: So the IAEA guide and just 6 simply accepting it straight up was not considered 7 why?
8 MS. THOMPSON: I will get to that in the 9 harmonization section.
10 DR. CORRADINI: Okay.
11 MS. THOMPSON: But to give you a preview, 12 there were three key components that the staff ---
13 PARTICIPANT: Wanted.
14 MS. THOMPSON: -- yes, identified.
15 DR. CORRADINI: All right, thank you.
16 MS. THOMPSON: But we'll get to that 17 towards the end.
18 Recognizing the interest and importance 19 for some perspective applicants of a process to assess 20 volcanic hazards, the working group issued a draft 21 outline of the draft guide and solicited public 22 comments and feedback. We even held a public meeting 23 in October to meet with perspective applicants and 24 gain their feedback on some of the content proposed in 25 the draft outline.
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49 1 In moving forward with the draft guide, 2 the staff identified several goals that should be met 3 by the regulatory guide, including to protect public 4 health, safety, and the environment, to provide an 5 open and traceable basis for regulatory decision 6 making.
7 We also considered what would be the 8 appropriate burden on an applicant using this draft 9 guide to assess volcanic hazards at their site and to 10 ensure that that burden should be commensurate with 11 the risk posed by the facility.
12 And we also wanted it to ensure that the 13 draft guide was consistent with the NRC's risk-14 informed, performance based framework as well as the 15 prior licensing actions and reviews that the staff had 16 undertaken.
17 DR. SCHULTZ: Jenise?
18 MS. THOMPSON: Yes?
19 DR. SCHULTZ: Just to back you up a bit, 20 no need to go to the slides, it wasn't on there, but 21 you said that you identified potential applicants and 22 got together with them to discuss going forward plans.
23 How were they identified, and how many came to meet?
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50 1 meeting notification system so that any, whether they 2 were a perspective applicant or a member of the 3 public, they were welcome to attend.
4 We had one person attend in person, and we 5 had about 25 people call in on the phone. Many of 6 them were from advanced reactor organizations, 7 perspective vendors for advanced reactor technologies.
8 There was at least one that's considering a site for, 9 I'm not sure what type of application.
10 And the way that we interacted and 11 identified these people, in addition to making a 12 public notice, is through our working group contact in 13 the Division of Advanced Reactors and Non-power 14 Utilization and Protection Facilities. I think I got 15 that right.
16 We went to the advanced reactor 17 stakeholder meeting the month before out public 18 meeting to present, at a high level, the draft outline 19 is coming. This is the public meeting notice, and we 20 would look forward to you attending and providing us 21 your early feedback on this draft outline of a draft 22 guide. So we leveraged the PMs that are on the 23 working group --
24 DR. SCHULTZ: Sure.
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51 1 they have.
2 DR. SCHULTZ: So you had an appropriate 3 outreach for the event ---
4 MS. THOMPSON: Yes. So the public meeting 5 notice went out through the advanced reactor ListServ, 6 I'm not sure, their mailing list that they have.
7 DR. SCHULTZ: Good.
8 MS. THOMPSON: And their stakeholders, 9 their monthly stakeholder's meeting.
10 DR. SCHULTZ: Sound's good, thank you.
11 MS. THOMPSON: The staff also identified 12 challenges associated with developing this draft 13 guide, most notably that there is no generally 14 accepted approach for developing or performing a 15 Volcanic Hazards Analysis or VHA. This is compared to 16 something like seismic hazards where many people are 17 familiar with the Probabilistic Seismic Hazard 18 Assessment, or PSHA.
19 The draft guide would also need to support 20 both siting decisions and potential design bases. The 21 staff and the working group also identified that 22 volcanic events are rare events with appreciable 23 uncertainties in the timing and nature of those 24 volcanic events.
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52 1 acknowledged, and I'll share with you on the 2 forthcoming slide, that there are a wide range of 3 demands placed on facilities from a volcanic event.
4 And there are limited design analyses available to 5 assess those particular demands from those hazards, 6 with the exception of ash fall, which I mentioned has 7 been considered in prior reviews.
8 So some of the volcanic hazards that the 9 working group considered important that would need to 10 be considered, as well as the associated demands, the 11 first that I'll share with you is ash fall. The photo 12 here shows a worker in the background, and the worker 13 is blowing the ash fall deposits off of the insulators 14 in an electrical switchyard. This is following a 15 volcanic eruption in Japan.
16 So unlike fly ash or what's in your 17 fireplace, volcanic ash is a mix of pulverized rock 18 and minerals, so it ranges in size up to about two 19 millimeters. And it's hardness is comparable is most 20 metals or alloys, so we're talking about things that 21 are very heavy.
22 They also can be conductive, especially 23 when they are damp from fog or a light rain, hence the 24 reason why this worker is blowing the ash fall 25 deposits off of these insulators so that they prevent NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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53 1 the arcing from the volcanic ash in the switchyard.
2 The airborne particle concentrations for 3 volcanic ash can be on the order of up to 100 4 milligrams per cubic meter. This will decrease 5 typically in the days or weeks following an eruption.
6 The physical loads resulting from the deposition of 7 volcanic ash at a site can range from 100 to 1,000 8 kilograms per square meter. This is comparable to a 9 snow load event at a facility. And this can increase 10 when the volcanic ash is wet.
11 And finally, volcanic ash can linger for 12 days or weeks after an eruption. And as we saw 13 following Mount St. Helens, volcanic ash can travel 14 not just tens or hundreds of kilometers but thousands 15 of kilometers affecting sites well removed from the 16 location of the ash source.
17 CHAIR BLEY: One thing you didn't talk 18 about there, and in the reg guide when you go through 19 the methodology, you don't give a lot of advice about 20 what failure modes could be induced by these events.
21 But when you get to the very tiny volcanic 22 ash, a thousandth of a millimeter, this stuff's so 23 small it could get into equipment in ways we don't 24 normally have to think about and probably interfere 25 with the equipment but possibly really damage it as NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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54 1 well.
2 Are you thinking of any other additional 3 information to be provided to applicants to have them 4 think about specific, how to think about, for all of 5 these hazards, the specific damage mechanisms that 6 might occur to SSCs at their site?
7 DR. SCHULTZ: And are there specific 8 threshold effects within that large range?
9 MEMBER DIMITRIJEVIC: That's missing from 10 the guide. And that's one of my biggest comments, 11 that there was no discussion about the connection of 12 SSCs in the failure modes connected with different 13 hazards, ash and all other hazards which you identify.
14 And that's where you actually have the nuclear 15 facility connects to this hazard through the failure 16 modes associated with different type of components and 17 --
18 CHAIR BLEY: Your simplified, well, you're 19 going to get to the methodology later.
20 MS. THOMPSON: Yes, we're going to get to 21 that.
22 CHAIR BLEY: But your simplified PRAs, and 23 I wish you had had a PRA person helping with this, 24 they have some problems we'll talk about later, but 25 they assume that the vulnerable SSCs fail.
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55 1 MS. THOMPSON: Okay.
2 CHAIR BLEY: Which makes it easy.
3 MS. THOMPSON: Yes.
4 CHAIR BLEY: As long as the person doing 5 the analysis understands what the challenge is to 6 their SSCs.
7 MS. THOMPSON: Will be.
8 CHAIR BLEY: -- and, you know, the heavy 9 weight, that's an obvious one. Some of the others 10 maybe are more subtle. And if you don't give them 11 guidance on that, it'll be a toss-up while they think 12 about it.
13 MEMBER DIMITRIJEVIC: That's a big piece 14 in this guidance, because you have a two screening, 15 one when there's 200 percent failure and one when 16 you're adding these two probabilities of hazards and 17 eruption to put as a failure probability.
18 MS. THOMPSON: Yes.
19 MEMBER DIMITRIJEVIC: But the failure 20 modes and related SSCs are not in there.
21 MS. THOMPSON: Okay.
22 MEMBER KIRCHNER: Jenise, do you, in your 23 center or activities, put out some kind of, I'm trying 24 to think about vehicles you have at your disposal to 25 communicate to the industry. But do you give NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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56 1 guidance, say, pick on something like seismic 2 analysis, something comparable, is there, to address 3 Dennis and Vesna's concern, do you put out any kind of 4 guidance that would suggest, separate from this reg 5 guide which is primarily citing how to protect, you 6 know, SSCs and especially safety-related or, so I 7 guess it's not all safety-related. This is not 8 necessarily safety-related. It's just power. But do 9 you see where I'm going?
10 MS. THOMPSON: Whether we issue --
11 MEMBER KIRCHNER: Just power.
12 MS. THOMPSON: -- something more specific?
13 MEMBER KIRCHNER: Yes.
14 MS. THOMPSON: The external hazard COE 15 has not done that. But I can take that back as a 16 comment to consider.
17 MEMBER KIRCHNER: I was just thinking 18 that the reg guide might get unduly complicated 19 if you tried to do equipment failure modes and 20 effects kind of analyses as, you know, guidelines 21 and so on, like you were asking.
22 CHAIR BLEY: Well, maybe it would be an 23 appendix or a separate document. But there ought 24 to be something. I read through the IAEA stuff, but 25 I haven't read it carefully enough to know if they dig NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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57 1 into that. But I didn't see it.
2 MEMBER DIMITRIJEVIC: Well, my personal 3 thinking is just a high level, there's a lot of 4 technical equipment will be susceptible to ash. In 5 the case of lava, you have to worry about the things 6 on the ground level, you know, like electrical, and 7 more operator actions can be affected. It can be just 8 a couple of paragraphs of general guidance, and then 9 they can do the full analysis when they submit them.
10 MS. THOMPSON: So that is part of the 11 reason why, in the draft guide, we included specific 12 information about hazards like volcanic ash so that an 13 applicant following this guide would look at the 14 particle size and consider the range of particles 15 sizes of ash that may affect that site.
16 So you'll see that that is captured in the 17 draft guide. I understand your point that we didn't 18 take it that step further to consider the failure 19 modes from those specific particle sizes within 20 specific SSCs.
21 MEMBER DIMITRIJEVIC: What's the type of 22 limit could be considered a factor with this, you 23 know?
24 MS. THOMPSON: Okay.
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58 1 the lava flow. So whatever, you have this next, you 2 know, in the third slide you will have this 3 pyroclastic flow which I'm not sure I ---
4 MS. THOMPSON: And when we got into the 5 volcanic hazards assessment, the physical approach, 6 and the flow chart in the presentation here, there is 7 a step in the process where an applicant can choose to 8 do an additional analysis considering specific 9 physical properties of specific structures, systems, 10 and components within their proposed facility, given 11 the volcanic hazards that screen in and have not been 12 ruled out at that point in the analysis. So there is 13 a place where this more detailed site-specific 14 analysis would occur.
15 MEMBER DIMITRIJEVIC: But you have a step, 16 and we will get to that.
17 MS. THOMPSON: Yes.
18 MEMBER DIMITRIJEVIC: Where you have 19 initial risk here, based on this initial risk, you 20 think you should put everything failed, then from 21 there. It doesn't have to go ---
22 MS. THOMPSON: Right. So ---
23 MEMBER DIMITRIJEVIC: So you have to 24 select what's ---
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59 1 that, because there are actually three different steps 2 where this may be addressed with increasing detail.
3 MEMBER DIMITRIJEVIC: Okay.
4 CHAIR BLEY: I would just say if you don't 5 do it attached to your reg guide ---
6 MS. THOMPSON: Consider an appendix?
7 CHAIR BLEY: -- you will eventually do it, 8 because you won't be happy with what you get. And 9 you'll be doing lots of RAIs, and that sort of thing.
10 MS. THOMPSON: Okay.
11 MEMBER BROWN: I don't know. I'd be 12 careful. I mean, it's starting to sound like we want 13 to provide all the design information inside the reg 14 guide and become very prescriptive about what they 15 have to look at, and how they look at it, and what the 16 potential mitigating actions ought to be. And that's 17 the same thing we face about trying to be too 18 prescriptive on designing some of the systems, 19 particularly the protection and safeguard systems that 20 we've looked at.
21 I think there's a balance in there. We 22 just can't fill this thing up with prescriptive 23 information. You want it covered, you want them to 24 evaluate the potential hazards and tell you, but not 25 try to tell them what they have to look at. That's NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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60 1 just my thought on it. It's just a little counter --
2 MEMBER KIRCHNER: I tend to agree with 3 Charlie too, because I'm thinking of the diesel 4 generators. When you see this threat to operating 5 your diesel generators then you go into a much more 6 detailed analysis as to whether I need oil filters or 7 not, as an example.
8 But to pile that all into the reg guide 9 might be asking for a lot --
10 MEMBER DIMITRIJEVIC: Well, because they 11 will have a step. We will get to the steps --
12 MS. THOMPSON: We'll get to the steps.
13 (Simultaneous speaking.)
14 MEMBER DIMITRIJEVIC: -- development.
15 MS. THOMPSON: And that point was 16 something that the working group considered, is we 17 wanted a guide that was broad enough that could be 18 considered at any site that may have volcanic hazards 19 present and making it not so descriptive that it 20 became cumbersome. You know, that was one of our 21 goals, was to be commensurate with risk and 22 appropriate burden.
23 So new vent opening, this shows a new vent 24 erupting in Hawaii. The opening of a new vent is 25 usually proceeded by several days or several weeks of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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61 1 precursory earthquakes which is triggered by magma or 2 molten rock rising from a duct beneath the surface.
3 The opening of a new vent results in 4 ground deformation, usually a rift will be one to 5 several kilometers long and somewhere between on and 6 ten meters wide. So we're talking about a significant 7 gash in the surface of the earth.
8 If that magma then erupts along that new 9 rift, there will be lava flows which may erupt on one 10 to two main vents in this new ground opening in a day.
11 The continued eruption would result in volcanic 12 ballistics and other ejecta. These may be up to 13 several meters in diameter and occur within about 14 several kilometers of the vent opening. So this is 15 not a point hazard right at the opening of the new 16 vent but can be a hazard from some distance away as 17 well.
18 It may result in the creation of a scoria 19 cone, and I was told to mention this, because today is 20 the 77th anniversary of the eruption of Paricutin, a 21 scoria cone in Mexico, so very timely for us.
22 There also may be a smaller volcanic 23 edifice as a result of the opening of a new vent. If 24 there are interactions with shallow ground water, 25 there also may be small blasts or surges also within NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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62 1 several kilometers of the vent. So the opening of a 2 new vent is a spatial consideration for some diameter 3 away from the new vent opening.
4 CHAIR BLEY: Tephra is ash or ---
5 MS. THOMPSON: Ash, small---
6 CHAIR BLEY: -- something like ash?
7 MS. THOMPSON: Small volcanic particles, 8 yes.
9 DR. SCHULTZ: Jenise, you mentioned that 10 there is usually some precursory indication that 11 something is going to happen. But that's usual, it's 12 not always.
13 MS. THOMPSON: It's not always, but it 14 would be more unusual for there to be no indication 15 than it would be unusual for there to be indication.
16 So typically, most likely there would be 17 precursory activity -- no activity, and then a 18 volcanic event where the new vent opening would be a 19 rare occurrence.
20 DR. SCHULTZ: All right. Okay. Thank 21 you.
22 MS. THOMPSON: Lava flows are another 23 hazard with significant demands placed on surrounding 24 facilities. The photo here is from Hawaii, the 2018 25 Kilauea East Rift eruption.
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63 1 The steaming vent in the background is the 2 two-kilometer-long rift from which that main lava flow 3 is erupting coming into the foreground of the photo.
4 Lava flows are molten rock at the surface 5 of the earth. They are very dense, up to 2,500 6 kilograms per cubic meter. And we're talking about 7 very hot molten rock, 1,000 degrees Celsius or more.
8 The heat capacity of a lava flow is 9 comparable to most metals. And the flow rate can vary 10 from about one until about 10 meters per second, or 11 about 22 miles per hour. And the flow rate will 12 depend on the local topography and other factors.
13 Although most lava flows will follow 14 topography, lateral breakouts can be common.
15 Additionally, lava flows have been known to damn 16 waterways resulting in localized flooding.
17 Another flow hazard that should be 18 considered are pyroclastic flows, which you may 19 sometimes see referred to as pyroclastic density 20 currents. And the photo here shows a mall pyroclastic 21 flow on Mount St. Helen's from 1980.
22 Pyroclastic flows are mixtures of 23 pulverized rock and gas -- excuse me -- they are hot, 24 greater than about 300 degrees Celsius, with deposit 25 densities that range from 1,000 to 2,000 kilograms per NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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64 1 cubic meter.
2 Unlike a lava flow, which is moving up to 3 about 10 meters per second, a pyroclastic flow is very 4 fast moving at hundreds of meters per second.
5 Additionally, pyroclastic flows, similar 6 to volcanic ash, can travel longer distances looking 7 at tens to upwards of a hundred kilometers from the 8 source vent.
9 And they also -- although smaller flows 10 will tend to stick to their topographic channel, a 11 larger flow may overtop barriers that could be 12 hundreds of meters high.
13 CHAIR BLEY: I assume they're called 14 "density currents" because they flow from high density 15 to low density; is that right?
16 MS. THOMPSON: I have seen both flow and 17 density currents.
18 CHAIR BLEY: Okay.
19 MS. THOMPSON: There are other volcanic 20 hazards that would be considered within the scope of 21 the volcanic hazards assessment outlined in the draft 22 guide.
23 These hazards would tend to be located 24 near the volcano or the source vent, except for debris 25 flows, which can flow tens of kilometers from event.
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65 1 And the photo here shows the debris flow 2 from Mount St. Helen's. This is along the Toutle 3 River and shows the deposit of the debris flow, 4 sometimes called a "lahar."
5 The bridge in the background, it's kind of 6 the green figure, is destroyed. And the rock in the 7 foreground is about two meters in diameter and was 8 carried in this debris flow.
9 And if you look very closely, there is a 10 small rock hammer on that rock for scale.
11 MEMBER DIMITRIJEVIC: How far is the 12 Toutle?
13 MS. THOMPSON: The Toutle River?
14 MEMBER DIMITRIJEVIC: Yes.
15 MS. THOMPSON: So, this did not reach 16 Trojan. So, this is within -- less than 50 kilometers 17 from the ---
18 CHAIR BLEY: Two things. I want to ask 19 you something about the list, but ---
20 MS. THOMPSON: Okay. I'm going to get to 21 the list.
22 CHAIR BLEY: -- for my colleagues, if you 23 ever get a chance to go visit Mount St. Helen's, do 24 it. The blast went about 20 miles.
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66 1 years after the event.
2 DR. CORRADINI: Not anymore.
3 CHAIR BLEY: Huh?
4 DR. CORRADINI: Not anymore.
5 CHAIR BLEY: Yeah, they are. I was there 6 just a couple years ago and they were --
7 DR. CORRADINI: But I thought there is new 8 growth.
9 CHAIR BLEY: There is new growth coming 10 back, but the old tress 20 miles out you'll see them 11 laying down.
12 I took your list against -- on your slide 13 against the list in the reg guide and against the list 14 in the IAEA-specific safety guide.
15 MS. THOMPSON: Uh-huh.
16 CHAIR BLEY: And pretty much the list and 17 your guide has picked up almost everything they talk 18 about there. It's kind of rearranged some of the 19 maybe lesser things in the group down here.
20 I had a question about the -- in the reg 21 guide, it says the earthquakes are typically less than 22 M5.
23 Is that always or what's "typical" mean or 24 generally -- generally less than M5, how big an 25 earthquake could we have?
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67 1 MS. THOMPSON: I think greater than 5 2 would be a very rare occurrence as to what a possible 3 --
4 CHAIR BLEY: Well, the whole thing's --
5 MS. THOMPSON: Maximum magnitude --
6 CHAIR BLEY: -- pretty darn rare anyway.
7 MS. THOMPSON: -- I'm going to defer to 8 our volcanologist.
9 CHAIR BLEY: Sure.
10 DR. HILL: Brittain Hill.
11 It's a little difficult to put a maximum 12 magnitude because it scales to the size of the 13 eruption and there have been some huge eruptions in 14 gas.
15 But typically --- for example, the 1980 16 eruption of Mount St. Helen's ---
17 CHAIR BLEY: Yeah.
18 DR. HILL: -- the May 18th was triggered 19 by a magnitude 5.1 earthquake, which the seismologists 20 said that was a fairly significant earthquake for that 21 part of the Pacific Northwest, magnitude 5.1.
22 CHAIR BLEY: Is it usually the earthquake 23 triggers the volcano or vice versa?
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68 1 earthquake than one of molten rock.
2 Paricutin, when that one started, there 3 were magnitude 3s and 4s as the magma moved up from 4 depth.
5 There's another well-instrumented eruption 6 in Russia, 1975. The Tolbachik eruption was, again, 7 magnitude 4 to about 4-1/2 as molten rock moved up 8 from tens of kilometers depth.
9 So, unless you're talking about an 10 extremely large eruption, something much larger than 11 Mount St. Helen's, the local earthquakes, the moment 12 magnitudes would be -- a magnitude 5 or less would be 13 a very good rule of thumb, but you can't rule out that 14 something bigger could happen in a giant sort of an 15 eruption.
16 Very typical like you would do for a 17 seismic hazard analysis, I'm not aware in the United 18 States that anything has a background source that has 19 a maximum magnitude of less than 5.5.
20 So, it seems very reasonable that a 21 volcanically sourced earthquake would be captured 22 within the regional seismic zones in the US seismic 23 source model.
24 CHAIR BLEY: Uh-huh.
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69 1 question about a -- it's site-specific. So, forgive 2 me, but Hebgen Lake outside of Yellowstone had a 3 significant earthquake in '59. It's worth visiting as 4 well to see what happened.
5 How do you sort out maybe cause and effect 6 after what you just said about Mount St. Helen's? Do 7 you -- would you -- if you have a situation like that 8 in an active zone -- and I'm not a geologist, so I may 9 not use the right clinical terminology -- how do you 10 -- would you enhance your assessment of the 11 probability of a volcano-like event as a result of, 12 you know, you had this rather massive earthquake there 13 and it's not that far, or do the seismic people do 14 their thing and the volcanologists do theirs, or is 15 there some coming together?
16 CHAIR BLEY: Well, they're mixed together.
17 The person we were talking to does both. I mean, 18 that's her field.
19 MEMBER KIRCHNER: But this is explicitly 20 a volcanology hazards ---
21 MS. THOMPSON: Yes.
22 MEMBER KIRCHNER: -- assessment and I'm 23 just wondering how you match the seismic if indeed 24 there's a situation where you might have cause and 25 effect, you know, one comes first and, boom, then NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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70 1 comes the volcano or vice versa.
2 MS. THOMPSON: So, the consideration of 3 the working group was -- assuming the moment magnitude 4 of less than or about 5, was that that moment 5 magnitude from the volcanic earthquakes would be 6 adequately captured in a seismic source model 7 performed by our seismology counterparts for the 8 specific site.
9 MEMBER KIRCHNER: Okay. All right.
10 CHAIR BLEY: I have a couple more 11 questions.
12 MS. THOMPSON: Okay.
13 CHAIR BLEY: Not on your slide, but in 14 your reg guide, one of the things grouped together at 15 the end are two things associated with debris 16 avalanches, and I have a question about each. Let me 17 put them both on the table.
18 One is if it's underwater, goes into 19 water, it could create a seiche ---
20 MS. THOMPSON: Yep.
21 CHAIR BLEY: -- or a tsunami.
22 MS. THOMPSON: I was just about to get to 23 that.
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71 1 ask, is there a volcano or defunct one that could have 2 a debris avalanche?
3 And for just the debris avalanche above 4 ground, not here, do you get something like the ash 5 falls associated with that?
6 Do they lead to a lot of ---
7 MS. THOMPSON: They will lead ---
8 CHAIR BLEY: -- dust and particles in the 9 air?
10 MS. THOMPSON: They will lead to dust and 11 particles in the air, but unlike ---
12 CHAIR BLEY: Are they local?
13 MS. THOMPSON: -- unlike ash fall it's not 14 going to be a hundreds-of-kilometer hazard.
15 CHAIR BLEY: And it doesn't have the heat 16 to lock it.
17 MS. THOMPSON: Yes.
18 CHAIR BLEY: Okay.
19 MS. THOMPSON: And compared to something 20 like a landslide that would just occur in, let's say, 21 a granitic mountain, you would have dust in the air 22 following the landslide, but you would not find dust 23 in the air several hundred kilometers away.
24 CHAIR BLEY: Okay. So, it would have to 25 be right on top of you.
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72 1 MS. THOMPSON: Yes. So, a debris 2 avalanche from a -- the collapse of a volcanic 3 edifice, you'll see dust.
4 But unless it's occurring contemporaneous 5 with the eruption of additional ash, you would not see 6 that ash fall traveling the distances that we see in 7 ash fall that's erupted from a volcano.
8 CHAIR BLEY: And two more small things.
9 On your slide, you list lightning. You don't list 10 that in your reg guide.
11 MS. THOMPSON: Oh, okay.
12 CHAIR BLEY: You might make them 13 consistent.
14 And the last thing is, and this is one I 15 know nothing about, the SSG21 ---
16 MS. THOMPSON: Uh-huh.
17 CHAIR BLEY: -- the IAEA report, also 18 mentions mud volcanoes, which aren't really volcanoes, 19 but then it says you can use the same kind of 20 analysis.
21 Are they anything to care about? I don't 22 know what they are.
23 DR. HILL: Mud volcanoes?
24 CHAIR BLEY: Mud, M-U-D.
25 DR. HILL: Yeah. Yeah. I know.
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73 1 CHAIR BLEY: I don't know what they are, 2 but they mention it. And then they say it's out of --
3 it's out of the scope of their document.
4 NRC staff doesn't mention it in there 5 document and then they say, oh -- the IAEA says, well, 6 although it's out of scope, you can use the same 7 techniques to look at these.
8 Is it --
9 MS. THOMPSON: I see Britt holding the 10 microphone.
11 CHAIR BLEY: Yeah. Britt, tell us, all 12 right, because I have no idea about that one.
13 DR. HILL: Brittain Hill.
14 The mud volcanoes I believe that IAEA was 15 referring to are the ones that can occur where you 16 have trapped over-pressured fluid in a large 17 sedimentary basin and they erupt, if you will, without 18 a seismic trigger.
19 So, they're not like sand blows that you 20 see, but they can just kind of spontaneously happen 21 under certain hydraulic conditions.
22 They are not volcanic phenomena. That is 23 why we didn't choose to do this.
24 CHAIR BLEY: Fair enough.
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74 1 ought to be looking at this and --
2 DR. HILL: I believe IAEA was putting it 3 in there because the methodology for looking at the 4 likelihood of a new mud volcano forming is very 5 similar to the methods that you would use for a new 6 volcano forming in, say, the Eastern Snake River 7 Plain.
8 CHAIR BLEY: Okay. Thanks.
9 MS. THOMPSON: And to address your 10 question about debris avalanches entering a body of 11 water and --
12 CHAIR BLEY: Yeah.
13 MS. THOMPSON: -- resulting in a seiche or 14 tsunami, that is a consideration that our 15 counterparts, the hydrologists, would consider in 16 their review.
17 In the review of tsunami and seiche they 18 consider -- they consider landslide-induced, which 19 would include the collapse of a volcanic edifice.
20 CHAIR BLEY: That's some of the biggest --
21 tsunamis have occurred --
22 MS. THOMPSON: So, that is considered 23 within the hydrology review.
24 CHAIR BLEY: Hydrology, okay. Perfect.
25 MS. THOMPSON: Yeah. So, a debris flow, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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75 1 for those who are unfamiliar with them, is a flow of 2 greater than 50 percent suspended solids.
3 As you can see from the photo, the 4 material that is carried in this debris flow can be 5 very large and, as you can see, they destroy a fair 6 amount of infrastructure in their path.
7 They're also capable of going over the 8 outside of their channels. So, although a flood may 9 stick to the channel and slightly over top of, a 10 debris flow often overtops the existing channels, yes.
11 And then we already discussed debris 12 avalanches as well as earthquakes. There are 13 additional interactions to consider from hydrothermal 14 systems, the emission of volcanic gas and then we also 15 mentioned lightning.
16 And, again, these are looking at hazards 17 that are close to the vent. So, within about ten 18 kilometers is where these would typically be 19 occurring.
20 So, now that we've given you a background 21 of the volcanic hazards, it's time to get to the meat 22 of the draft guide and the lovely flowchart outlining 23 the general approach for the volcanic hazards 24 assessment, or the VHA.
25 There are --
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76 1 CHAIR BLEY: I'm going to interrupt you 2 here --
3 MS. THOMPSON: Okay.
4 CHAIR BLEY: -- because I want to say a 5 few things about this ---
6 MS. THOMPSON: Okay.
7 CHAIR BLEY: -- and about the whole 8 methodology.
9 First is, and your words in the text kind 10 of acknowledge this, acceptable/unacceptable, U and A, 11 are kind of misnomers.
12 Especially the unacceptable really isn't 13 unacceptable. It's more likely it's not yet screened 14 or not yet dealt with.
15 The acceptable isn't really defined 16 anywhere except in the text, and it's really no 17 further analysis. So, those words at least set me off 18 a little bit.
19 I'm going to just mention something to 20 you. As I read through it all, it struck me one could 21 put labels on each of your stages.
22 And the first one is really an existence 23 issue, is what you're looking for, is this a 24 possibility.
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77 1 really all of them are kind of screening in different 2 ways below this, but it's really a distant screen on 3 that one.
4 The next one is really a "no damage 5 leading to release" kind of thing. It's sort of the 6 first risk-oriented thinking.
7 And then you get a couple that are really 8 frequency. They aren't risks, but they're saying just 9 the frequency is too low to matter.
10 And finally, you get down to No. 6, which 11 is really a real PRA by that point. And 7, the same 12 way. So, something to think about.
13 And then when you get into the details, 14 I'm going to ask you about your PE and your PH, the 15 probability of eruption and probability of the hazard 16 reaching the site, and what kind of criteria you have.
17 And as you move from one to the other, 18 you're attaching what you say is essentially the same 19 functional simplified PRA, and I think that's not --
20 it's not clear to me, reading it, how the criteria for 21 acceptance change, as you go from having just a PE or 22 a PH and some associated damage, all the way down 23 through the others.
24 So, I'll raise that when you get to 25 particular places, but I just wanted to give an NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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78 1 overall comment on the layout.
2 I think it's a very sensible idea, it lets 3 you progress into more and more work as you need it, 4 and it lets you keep as simple as possible, but the 5 simplicity in the text is oversimplified.
6 I don't think it gives people the idea of 7 how to evaluate where they are.
8 DR. CORRADINI: I guess I wanted to ask --
9 Dennis is much more astute about how you do this, but 10 I guess I was going to use your examples and ask how 11 far down the chain each of those would have been 12 analyzed.
13 In other words, pick Yucca Mountain. As 14 I understand the probabilistic analysis for Yucca 15 Mountain, it essentially went through all six of your 16 steps whereas Columbia or Trojan would not have.
17 They would have stopped somewhere in the 18 middle and done something that covered them enough 19 that they would -- they'd stop the process.
20 It strikes me that I would have some sort 21 of practical examples of how you pass through these.
22 MS. THOMPSON: Okay.
23 MEMBER DIMITRIJEVIC: Yeah. Actually, I 24 thought --- and I have similar comments to Dennis. I 25 don't think you need to have a six and, you know, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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79 1 develop --- because the six is the part of developing 2 the detailed risk insight.
3 But that's why, Dennis, there is no really 4 --- I mean, evaluating design basis would not be 5 separated from this.
6 The other thing which I just think, which 7 Mike just said, whenever we come to one step, let's 8 have an example of what that step will do.
9 And we can choose Columbia as an example 10 and say what would that mean for that site if they are 11 applying this reg guide.
12 MS. THOMPSON: All right.
13 MEMBER DIMITRIJEVIC: Something like that.
14 MS. THOMPSON: I will say that Columbia 15 got all the way to Step 7 because Columbia did 16 develop, and still has to this day, mitigating actions 17 that they take.
18 MEMBER DIMITRIJEVIC: Let me be specific.
19 We would just use as an example.
20 MS. THOMPSON: Okay.
21 MEMBER DIMITRIJEVIC: We don't need to 22 know what they did actually.
23 MS. THOMPSON: Okay.
24 MEMBER DIMITRIJEVIC: But use as an 25 example of --
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80 1 MS. THOMPSON: And we have some examples 2 for the steps that I will walk through. None of them 3 are reactor examples because we were trying to be 4 neutral in --
5 DR. CORRADINI: Sure.
6 MS. THOMPSON: -- providing examples for 7 each of the steps, but we do have examples that --
8 DR. CORRADINI: Okay.
9 MS. THOMPSON: -- I will share.
10 DR. CORRADINI: Good.
11 MS. THOMPSON: So, Dennis already 12 mentioned that we have the off-ramps for each of the 13 -- most of these steps here. So, the steps are listed 14 on the slide here.
15 I'm not going to read them to you, but 16 what I would like to point out is that most of these 17 steps allow for the application of risk insights and 18 then the option to determine if the hazard is 19 potentially significant.
20 And if it is, to continue the analysis.
21 And if the hazard is not significant, to document the 22 results and end the analysis.
23 So, again, looking back to that goal that 24 we had set for the draft guide to make sure that the 25 burden on an applicant using this VHA is commensurate NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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81 1 with the rest, so we've captured that through the 2 application of risk insights and these numerous off-3 ramps so that the analysis can be complete before you 4 reach mitigation actions if the risk is deemed to be 5 not significant.
6 We will now walk through these initial 7 steps, which I think is what everybody is interested 8 in.
9 So, the first step is to gather the 10 initial information. This can be summarized as three 11 key points; and those are to consider the time period 12 of interest, the region of interest, and the tectono-13 magmatic model.
14 For the time period of interest the draft 15 guide outlines the Quaternary period, or 2.6 million 16 years old, as sufficient.
17 This is consistent with the standard 18 review plan, SRP, Section 251 for the geologic site 19 characterization that we currently do for new 20 applications.
21 And the staff determined that the 22 Quaternary period would capture the uncertainties in 23 the timing and character of past volcanic events.
24 DR. CORRADINI: Well, there's nothing --
25 there's nothing new about that.
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82 1 MS. THOMPSON: No. The Quaternary period 2 for geologic site characterization is something that 3 we have been using and continue to use.
4 So, that was the working group's decision 5 that the 2.6 million year period of interest would be 6 sufficient for this as well.
7 DR. CORRADINI: Okay.
8 MEMBER DIMITRIJEVIC: So, do we have a map 9 of United States with that period showing all the 10 sites? Do we have a map like, you know.
11 MS. THOMPSON: A geologic map?
12 MEMBER DIMITRIJEVIC: Yeah, geologic 13 volcano-related map.
14 DR. CORRADINI: Yeah. I guess she's going 15 where I was ---
16 MS. THOMPSON: Oh.
17 DR. CORRADINI: -- going, which is now you 18 ---
19 MS. THOMPSON: Do we have a map of every 20 ---
21 MEMBER DIMITRIJEVIC: Yes.
22 MS. THOMPSON: -- Quaternary volcanic 23 feature in the United State?
24 MEMBER DIMITRIJEVIC: Yes.
25 DR. CORRADINI: Yes.
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83 1 MS. THOMPSON: I don't have one, but there 2 are -- I will say that Quaternary geology is captured 3 in geologic maps that are available for the entirety 4 of the United States.
5 So, a geologist would be able to obtain a 6 geologic map for a given area, and that geologic map 7 would have any Quaternary volcanic deposits mapped on 8 it.
9 MEMBER DIMITRIJEVIC: That's what I'm 10 asking you.
11 MS. THOMPSON: So, we --
12 MEMBER DIMITRIJEVIC: So, somebody has to 13 go and find out --
14 MS. THOMPSON: No. These are geologic 15 maps that are in existence, and we would be able to 16 identify the volcanic units on any geologic map 17 produced for the United States.
18 MEMBER DIMITRIJEVIC: Okay. In this 19 period, Quaternary --
20 MS. THOMPSON: Yeah. They don't produce 21 specific maps just showing Quaternary volcanic 22 features in the United States, but those can be 23 deciphered from a geologic map.
24 MEMBER DIMITRIJEVIC: Okay.
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84 1 that we have as the geologic staff here --
2 MEMBER DIMITRIJEVIC: Whoever wants to --
3 MS. THOMPSON: -- at NRC.
4 MEMBER DIMITRIJEVIC: -- site the nuclear 5 plant will be able to see, should we worry about 6 volcano or hazard.
7 MS. THOMPSON: Yes.
8 MEMBER DIMITRIJEVIC: All right.
9 MS. THOMPSON: Yes. So, the second 10 component of gathering initial information is to 11 consider the region of interest, or what we've been 12 calling the ROI, for this initial screening.
13 And, again, consistent with SRP Section 14 251 for geologic site characterization, the working 15 group determined that for surface hazards a 320-16 kilometer radius from the site would be sufficient.
17 Recognizing that the ash fall hazard can 18 travel much further than 320 kilometers for ash fall 19 hazards, the draft guide recommends that the radius be 20 extended to capture the Quaternary volcanoes that 21 might affect the design or operation of the facility.
22 And this is consistent with what we do for 23 other hazards, how we would capture a large seismic 24 source outside of the 320-kilometer radius that may 25 have the ability to affect the design or operation of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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85 1 the facility.
2 MEMBER MARCH-LEUBA: Yeah. I'm looking at 3 the ash cloud for the 2010 Iceland eruption.
4 MS. THOMPSON: Okay.
5 MEMBER MARCH-LEUBA: And it made it all 6 the way --- it came up from Iceland and made all the 7 way --- halfway to Siberia, to Italy, to --- I mean, 8 it covered half the world.
9 MS. THOMPSON: Mm-hmm.
10 MEMBER MARCH-LEUBA: So, the 320 11 kilometers looks a little small for ---
12 MS. THOMPSON: Which is why, for ash fall 13 hazards, we recommend the extension of that radius to 14 include ---
15 MEMBER MARCH-LEUBA: Yeah, but this is ---
16 MS. THOMPSON: -- the potential area.
17 MEMBER MARCH-LEUBA: -- like 5,000 18 kilometers.
19 MS. THOMPSON: And we will actually get to 20 that in Step 2 where an applicant would perform a 21 deterministic screening for the hazard that may affect 22 the site where they would consider the most ---
23 MEMBER MARCH-LEUBA: This was a problem 24 for flying airplanes, not for a stationary pump ---
25 MS. THOMPSON: Yes --
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86 1 (Simultaneous speaking.)
2 MEMBER MARCH-LEUBA: -- can't have a 3 filter, but 320 looks awfully small for something that 4 happen ---
5 MS. THOMPSON: Yeah.
6 PARTICIPANT: Well, 320 is surface.
7 MS. THOMPSON: Yeah. 320 is just for the 8 surface hazard. So, this is for things like ---
9 MEMBER MARCH-LEUBA: Okay.
10 MS. THOMPSON: -- lava flow, the new vent 11 opening, the debris flow.
12 MEMBER MARCH-LEUBA: I see.
13 MS. THOMPSON: So, we specifically call it 14 ash fall hazards as being separate and different from 15 this 320-kilometer radius.
16 MEMBER DIMITRIJEVIC: You have here 17 something which I strongly object in any PRA work. I 18 don't really like where they're short two decimal 19 places in high uncertainty.
20 You have here 320 kilometers because it 21 obviously comes from 200 miles.
22 MS. THOMPSON: Mm-hmm.
23 MEMBER DIMITRIJEVIC: This is a huge 24 uncertainty thing. We are showing like we know 25 something so it's 320.
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87 1 And then if you put 322 kilometers, you 2 will be absurd. 320 is absurd, too. Either put 300 3 kilometers or 200 miles.
4 MS. THOMPSON: Okay.
5 MEMBER DIMITRIJEVIC: Because 320 6 kilometers, it seems like we really know --
7 CHAIR BLEY: But it's not PRA. It's 8 significant figures --
9 MEMBER DIMITRIJEVIC: Yeah.
10 CHAIR BLEY: -- which you did a long time 11 ago.
12 MEMBER DIMITRIJEVIC: Right. So, the 13 other thing is like --
14 MS. THOMPSON: Okay.
15 MEMBER KIRCHNER: So, Vesna, the next time 16 we see 1.783 times 10 to the minus whatever, would you 17 correct those people?
18 MEMBER DIMITRIJEVIC: Probably not.
19 (Simultaneous speaking.)
20 MEMBER BALLINGER: I call it the TI-89 21 syndrome.
22 MEMBER DIMITRIJEVIC: You know, like this 23 was about this dinosaurs, you know, million and six 24 years ---
25 MS. THOMPSON: Mm-hmm.
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88 1 MEMBER DIMITRIJEVIC: -- so, you know, old 2 because somebody is working --
3 MS. THOMPSON: And I've made a note.
4 Okay. So, the ---
5 MEMBER DIMITRIJEVIC: You can use miles.
6 I mean, I don't see why you don't use the miles.
7 MS. THOMPSON: Okay.
8 MEMBER DIMITRIJEVIC: At least it's 9 probably 200 miles.
10 MS. THOMPSON: Yes.
11 MEMBER DIMITRIJEVIC: Yeah.
12 MS. THOMPSON: So, the third component in 13 gathering initial information is to consider the 14 tectono-magmatic model.
15 The tectono-magmatic model is a large-16 scale understanding of the geologic processes that are 17 controlling volcanism in the region of interest over 18 the time period of interest.
19 The example shown here is from the 20 essential part of the Oregon Cascades. Each of the 21 stars represents a volcano. They're labeled as "N,"
22 "M," "S" and "BT."
23 For those familiar with the area, these 24 are North Sister, Middle Sister, South Sister and 25 Broken Top.
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89 1 The black dots are volcanic vents, and the 2 lines shown on this figure are fault lines.
3 DR. CORRADINI: This is by Sisters, the 4 town.
5 MS. THOMPSON: Yes.
6 Every feature shown on this figure is less 7 than half a million years old. So, all of them are 8 within the Quaternary period of interest, are a 9 hypothetical site, they are within the region of 10 interest.
11 But if we look at the tectono-magmatic 12 model for this region, it would show us that only the 13 two youngest volcanoes, those labeled as "M" and "S,"
14 or South and Middle Sister, are consistent with our 15 understanding of the processes driving volcanism in 16 this area.
17 So, if we were considering this potential 18 site, a VHA would only need to consider the two 19 volcanoes, Middle and South Sister, that are within 20 the region of interest, are of the age within the time 21 period of interest and are consistent with the 22 tectono-magmatic model.
23 CHAIR BLEY: I hate to ask you two 24 questions on the models. In the Reg Guide --
25 MS. THOMPSON: Yes.
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90 1 CHAIR BLEY: -- under Step 1 ---
2 MS. THOMPSON: Uh-huh.
3 CHAIR BLEY: -- which is where you are, 4 there's two, to me, contradictory statements. The 5 first is, if there's evidence of the Quaternary 6 volcanism in the regions of interest, a conceptual 7 model of tectono-magmatic processes should be 8 developed.
9 The next paragraph says, if the hazard can 10 --- if you're not consistent with the model, screen it 11 out.
12 So, do we develop a model or do we believe 13 the one that's there or why do you have those two 14 statements?
15 You know, if you're going somewhere where 16 you don't have a model you believe in, I guess you'd 17 have to develop one, but then much of the rest of that 18 section keeps saying if you're not consistent with 19 that model, screen it out.
20 Nothing warns you to double-check the 21 model to see if it's right, to see if you've got some 22 problem.
23 MS. THOMPSON: I'm just reading the 24 section that you're referring to --
25 CHAIR BLEY: Oh.
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91 1 MS. THOMPSON: -- so that I can --
2 CHAIR BLEY: Okay. It's paragraph 3 and 3 4.
4 MS. THOMPSON: On page 12?
5 MEMBER DIMITRIJEVIC: Yes.
6 CHAIR BLEY: On page 12.
7 MS. THOMPSON: Okay.
8 CHAIR BLEY: And then it comes up three 9 paragraphs later --
10 MS. THOMPSON: Okay.
11 CHAIR BLEY: -- in the last paragraph, but 12 it's just those two paragraphs that bothered me.
13 MS. THOMPSON: Okay.
14 CHAIR BLEY: Because I read the first one 15 that said, develop your model, and I read the next one 16 and it says, if you're not consistent with the model, 17 screen it out.
18 MS. THOMPSON: I'm going to take a note to 19 bring this back to the working group and ---
20 CHAIR BLEY: I think that's best.
21 MS. THOMPSON: -- determine whether this 22 was just an oversight or a typo, but we'll ---
23 CHAIR BLEY: What you really wanted to 24 say, yeah.
25 MS. THOMPSON: We'll confirm this.
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92 1 CHAIR BLEY: Okay.
2 DR. CORRADINI: Is there --- I'll wait 3 until you're done.
4 MS. THOMPSON: Okay.
5 DR. CORRADINI: Is there something --- the 6 way you describe this, certain things are in and 7 certain things are out.
8 And that's because of age or because of 9 severity of the eruption known within the age limit?
10 MS. THOMPSON: It's because of the 11 processes that are resulting in the volcanism in the 12 area. So, in the tectono-magmatic model, another 13 example of this would be volcanism in Hawaii.
14 So, the hot spot there is currently on the 15 big island. So, on the island of Hawaii. You 16 wouldn't consider a new vent opening on Kaua'i because 17 although there is evidence of volcanism there, it's a 18 volcanic island arc, there is no active process under 19 the island of Kaua'i that would be consistent with 20 volcanism likely to occur in the future.
21 So, that's what the --
22 DR. CORRADINI: That's based on a 23 geologist's judgment?
24 MS. THOMPSON: Yes.
25 DR. CORRADINI: Okay.
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93 1 CHAIR BLEY: Well, and the history, you 2 know --
3 MS. THOMPSON: Yeah.
4 DR. CORRADINI: No, I understand.
5 CHAIR BLEY: -- that they started over 6 here and ---
7 DR. CORRADINI: I understand that.
8 CHAIR BLEY: -- now they're over here.
9 DR. CORRADINI: I understand that. But I 10 guess with all the little black dots, I first thought 11 they were outside of the time span ---
12 MS. THOMPSON: No.
13 DR. CORRADINI: -- but you're saying it's 14 not just outside of the time span, they're outside of 15 --- they're not being considered because of something 16 about the physical mechanism ---
17 MS. THOMPSON: Yes.
18 DR. CORRADINI: -- which caused the event.
19 CHAIR BLEY: Uh-huh.
20 MS. THOMPSON: So, eruption along any of 21 the vents to the east in this photo -- so, between BT, 22 or Broken Top, and the fault zone --- any of those 23 vents are not consistent with what is driving 24 volcanics in that area.
25 CHAIR BLEY: Within the time period of --
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94 1 MS. THOMPSON: Within the time period of 2 interest, yes.
3 DR. CORRADINI: Okay. That's fine.
4 MS. THOMPSON: So, we're looking at --
5 it's a three-pronged consideration. It's what is 6 within the Quaternary period, what is within the 7 region of interest, and then what is consistent with 8 the geologic processes going on in that area for the 9 time period that we're considering.
10 MEMBER DIMITRIJEVIC: And how would one 11 know those geological processes?
12 DR. CORRADINI: You have to be a 13 geologist.
14 MS. THOMPSON: Yes.
15 DR. CORRADINI: You have to be a geologist 16 and studied it.
17 MEMBER DIMITRIJEVIC: Okay. All those 18 dots will be on the maps for the geological region, 19 right?
20 MS. THOMPSON: Yes. Yes.
21 DR. CORRADINI: But her point was only the 22 two or three to the ---
23 MEMBER DIMITRIJEVIC: No I know, but I just 24 try to see from the two -- like you want to screen all 25 these 300 kilometers.
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95 1 So, I was wondering can you screen without 2 having a geologist? That's my question.
3 MS. THOMPSON: It would be very difficult 4 to go through this process without a geologist. It 5 would be nearly impossible to ---
6 MEMBER DIMITRIJEVIC: If I am in 7 Massachusetts, would it be difficult if there is 8 nothing around -- I mean, there have to be areas of 9 the United States where you don't need the geologist.
10 DR. CORRADINI: I assume you have your 11 green light on.
12 MS. THOMPSON: There are regions of the US 13 where there are not volcanic hazards that would be 14 considered, and that would be a determination made by 15 the geologists as part of the geologic site 16 characterization.
17 If there are potential sources of 18 volcanism in the region, this would be the approach 19 that that geologist would then take to assess those 20 potential volcanic hazards.
21 But if we're looking at a hypothetical 22 site in Massachusetts, there are going to be other 23 geologic hazards to consider other than volcanism that 24 would be captured ---
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96 1 was in a Hyatt Regency ---
2 MS. THOMPSON: -- within the geologic site 3 characterization.
4 MEMBER KIRCHNER: -- in Cambridge and I 5 got a wake-up call one morning. The bed started going 6 back and forth.
7 So, you may not have any volcanic threats, 8 but the seismologists or geologists are going to point 9 to other --
10 MEMBER DIMITRIJEVIC: You know, in seismic 11 we have that map of United States which clearly 12 defines region where there is high risk, low risk, you 13 know, and there is the four region of United States.
14 I was wondering if something like that 15 exists for ---
16 MS. THOMPSON: There are numerous geologic 17 hazard maps that the United States Geologic Survey 18 produces and updates.
19 There are earthquake hazard maps. There 20 are landslide hazard maps. There are floodplain maps.
21 There are -- I'm trying to think of the other ones 22 that I have seen.
23 There are many different geologic hazards 24 in geology. It's not just -- we're not just looking 25 at an earthquake or we're not just looking at a body NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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97 1 of water.
2 We're looking at sinkholes. We're looking 3 at rockslides. We're looking at rockfalls. We're 4 looking at volcanoes. We're looking at faults. We 5 are looking at a number of hazards that may occur 6 based on the geology at that specific site.
7 So, if the site has a potential source of 8 volcanism, this is an appropriate method. If there is 9 no source of volcanism, that site would still be 10 subject to the regular geologic site characterization 11 and review by the geology staff.
12 Did that answer your question?
13 MEMBER DIMITRIJEVIC: Yeah.
14 MS. THOMPSON: Okay. So, if after the 15 initial screening there are no sources of volcanism 16 that are within the time period of interest occurring 17 within the region of interest and that are consistent 18 with the tectono-magmatic model, an applicant using 19 the VHA would have the option to complete the analysis 20 and document their results.
21 if there are sources of volcanism that are 22 of Quaternary age, within the region of interest, and 23 consistent with the tectono-magmatic model, an 24 applicant would proceed to Step 2, which is to perform 25 a deterministic screening.
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98 1 This deterministic screening would 2 consider the characteristics --
3 CHAIR BLEY: I'm going to interrupt you 4 for two reasons.
5 MS. THOMPSON: Yes.
6 CHAIR BLEY: You're about halfway through.
7 MS. THOMPSON: Yes.
8 CHAIR BLEY: And we've only been here an 9 hour1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> and a half, but the coffee shop closes at 3:00.
10 (Laughter.)
11 CHAIR BLEY: So, why don' we take our 12 break now ---
13 MS. THOMPSON: Okay.
14 CHAIR BLEY: -- and then we can come back 15 and finish up the whole thing later because I think 16 we're now moving into the meat of the ---
17 MS. THOMPSON: Yes.
18 CHAIR BLEY: -- methodology and it's kind 19 of different. So, if that's okay, we will recess 20 until five til.
21 (Whereupon, the above-entitled matter went 22 off the record at 2:38 p.m. and resumed at 2:56 p.m.)
23 CHAIR BLEY: We are back in session. All 24 members, please come to your seats and you're back on.
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99 1 Step 2, which is the performance of the deterministic 2 screening.
3 So, this is considering the 4 characteristics of the Quaternary volcanoes that are 5 within the region of interest and are consistent with 6 the tectono-magmatic model.
7 Within the deterministic screening an 8 applicant would evaluate uncertainties in the buried 9 or eroded record.
10 They can use information from analogs or 11 from numerical modeling to quantify and further reduce 12 uncertainties in the available information.
13 This may include how far a hazard could 14 credibly travel from the source to some distance and 15 whether that hazard would reach the site.
16 This may be used --- a bounding evaluation 17 may be used to determine that distance from the 18 volcano to the farthest extent of the hazard and 19 whether that would have effect on the site.
20 And if there is an associated uncertainty, 21 how uncertain is that credible distance?
22 CHAIR BLEY: That may involve some 23 atmospheric modeling as well as ---
24 MS. THOMPSON: Depending on the ---
25 CHAIR BLEY: -- volcanic.
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100 1 MS. THOMPSON: Yeah.
2 CHAIR BLEY: Okay.
3 MS. THOMPSON: So, the example that I have 4 for a deterministic screening is from lava flows that 5 were measured off of Mt. Cameroon in the Republic of 6 Cameroon in Central Africa.
7 So, the measured flows are shown as the 8 lava flow length in kilometers on the x axis, and the 9 frequency of occurrence of a lava flow of that length 10 is shown on the y.
11 This data allows an analyst to fit a 12 statistical function to histogram data to develop a 13 likelihood estimate for the maximum length of the lava 14 flows from Mt. Cameroon.
15 So, if we were to consider a site near Mt.
16 Cameroon within ten kilometers, based on the data 17 shown here we would assume that the lava flow hazard 18 would most likely be considered in the VHA and 19 considered for additional analysis in the subsequent 20 steps.
21 Similarly, if we were considering a site 22 that was 20 kilometers or more away from Mt. Cameroon, 23 based on this data here our deterministic screening 24 may tell us -- well, would probably tell us that lava 25 flows from Mt. Cameroon do not pose a credible hazard NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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101 1 to the proposed site assuming that the mechanisms that 2 were driving the lava flow lengths produced in the 3 mapped data are those same mechanisms that will 4 produce future lava flows.
5 MEMBER DIMITRIJEVIC: How about lava flow 6 for this site?
7 MS. THOMPSON: Huh?
8 MEMBER DIMITRIJEVIC: How about lava flow 9 for this site? Do we have information of that?
10 MS. THOMPSON: I do not have information 11 on that with me today, but --
12 MEMBER DIMITRIJEVIC: I know, but does it 13 exist?
14 MS. THOMPSON: Yes.
15 MEMBER DIMITRIJEVIC: Lava flow --
16 MS. THOMPSON: So, we would find -- lava 17 flow information, yes.
18 MEMBER DIMITRIJEVIC: Yes.
19 MS. THOMPSON: If it's available.
20 MEMBER DIMITRIJEVIC: And all other 21 hazards associated.
22 MS. THOMPSON: Yes. So, lava flows are a 23 hazard that -- I won't say that it's the easiest one 24 to find data for, but a field geologist would be able 25 to go out to the site and walk the area and determine NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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102 1 what are the flows.
2 There would also usually be geologic maps 3 available that would show the ages of those respective 4 flows that would be considered. And that is how the 5 data was obtained for this example here from Mt.
6 Cameroon.
7 MEMBER RICCARDELLA: Isn't lava flow 8 directionally dependent?
9 MS. THOMPSON: It can be. Lava flows will 10 be channelized based on topography. So, some of these 11 will be -- could be flow covering flow, which is why 12 something to be considered is the buried or eroded 13 record that may be missing.
14 MEMBER DIMITRIJEVIC: Do you know what 15 hazard was analyzed for the Columbia?
16 MS. THOMPSON: For Columbia, they 17 considered volcanic ash. So, that was the hazard that 18 screened in as credible for the site, while the flow 19 did not, because of its location far from a source.
20 So, in a deterministic screening for 21 Columbia given the location, a surface hazard like a 22 debris flow or a lava flow would not screen in because 23 of the distance that it's located from the source 24 volcano.
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103 1 because realistically in our geologic record, and from 2 direct observation of the 1980 eruption of Mount St.
3 Helen's, we have seen volcanic ash reach the Columbia 4 site.
5 MEMBER DIMITRIJEVIC: Well, you have said 6 that we have within 300 miles, but it's my feeling 7 that we deem these 300 miles like between hundred 8 miles and 300 only thing to consider would be the ash 9 and everything -- all other hazards will be less than 10 maybe 50 or 100 miles.
11 MS. THOMPSON: It is going to depend.
12 Because, as I discussed with the pyroclastic flows, 13 there is a possibility for larger volume pyroclastic 14 flows to travel further.
15 So, that is what the deterministic 16 screening would allow an applicant to do is to 17 consider the spectrum of volcanic hazards that could 18 result from the volcanic source and whether those 19 volcanic hazards could credibly reach the proposed 20 site.
21 DR. CORRADINI: So, to say it another way 22 -- I think I know where Vesna's going.
23 CHAIR BLEY: Uh-huh.
24 DR. CORRADINI: To say it another way, is 25 it -- to go back to your examples of the various NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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104 1 hazards, each one of these hazards would have to have 2 some sort of deterministic length scale to say either 3 you're in or you're out.
4 MEMBER DIMITRIJEVIC: Right.
5 MS. THOMPSON: Yes. And that would be 6 performed at this step.
7 DR. CORRADINI: And if all of them are 8 out, then you're out.
9 MS. THOMPSON: Yes.
10 DR. CORRADINI: But if some are in, you 11 have to consider that hazard.
12 MS. THOMPSON: Yes.
13 DR. CORRADINI: Okay.
14 MS. THOMPSON: Yes.
15 CHAIR BLEY: But if you don't have enough 16 data, then you take what you had and do a SSHAC 17 process with it?
18 MS. THOMPSON: Yeah. And we will get to 19 that.
20 PARTICIPANT: Do a what?
21 MS. THOMPSON: Do a SSHAC process, the 22 Senior Seismic Hazard ---
23 PARTICIPANT: Oh, SSHAC.
24 MS. THOMPSON: -- Analysis Committee.
25 PARTICIPANT: Oh, okay. Yeah. Sure.
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105 1 PARTICIPANT: Not seismic anymore ---
2 MS. THOMPSON: Yeah.
3 PARTICIPANT: -- but they're doing the 4 same thing for floods and ---
5 PARTICIPANT: Okay.
6 MS. THOMPSON: Yeah. And we'll get to 7 that in a later set, but that is the general idea that 8 --- assess whether a hazard potentially exists, 9 whether it's --- it has to be the Quaternary age, and 10 the region of interest consistent with the tectono-11 magmatic model.
12 If the hazard does exist consistent with 13 those three factors, then you would perform the 14 deterministic screening.
15 For the example here, if you're within ten 16 --
17 (Simultaneous speaking.)
18 MEMBER DIMITRIJEVIC: -- determine the 19 distance between those two because you already put 300 20 kilometers in the first one, right? So, now you want 21 to screen all that.
22 MS. THOMPSON: Yes.
23 MEMBER DIMITRIJEVIC: You have to find the 24 place where the ash will not get 300 kilometers from 25 the place.
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106 1 MS. THOMPSON: Not necessarily not get 2 there. You can still move through the process with a 3 volcanic ash fall hazard, and then you reach either 4 Step 6 where you evaluate your design bases to see if 5 your facility could withstand the loads from that 6 volcanic ash, or you proceed to Step 7 ---
7 MEMBER DIMITRIJEVIC: That makes sense.
8 MS. THOMPSON: -- and consider mitigation 9 actions, which is what was done for Columbia.
10 MEMBER DIMITRIJEVIC: I was only trying to 11 establish difference between 1 and 2 because that's 12 not really clear.
13 You already put some distance of 300 14 kilometers and now we are ---
15 MS. THOMPSON: So, the distance for 300 is 16 to capture the volcanic source. The screening here is 17 to consider individual hazard.
18 So, in the 320 -- or the 200-mile radius 19 we're looking at any source within that radius that is 20 of Quaternary age and consistent with the model.
21 And then based on that source at the 22 deterministic screening level, we consider the 23 individual volcanic hazards that may occur from that 24 source and consider their maximum credible distance 25 and whether the site is within that distance and would NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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107 1 be affected by that hazard.
2 So, if we wanted to use the Columbia 3 example, we would screen in the Cascade volcanoes like 4 Mount St. Helen's, we would then consider the volcanic 5 hazards from Mount St. Helen's with the pyroclastic 6 flow --
7 MEMBER DIMITRIJEVIC: I understand that.
8 MS. THOMPSON: -- reach to the site.
9 MEMBER DIMITRIJEVIC: My question is, are 10 you going to screen anything in additional in Step 2?
11 Because you already putting within 300 kilometers 12 which assume that's average hazard -- longest hazard 13 distribution.
14 MS. THOMPSON: So, I think the key point 15 in the 320 or 200-mile radius is that is the source of 16 the hazard, and then the deterministic screening is 17 for the hazard itself.
18 So, we're looking at the source in Step 1, 19 and then we're looking at the likelihood of the hazard 20 reaching the site in the deterministic screening.
21 DR. CORRADINI: It makes sense.
22 CHAIR BLEY: Well, except for one thing.
23 If ash can go further --
24 MS. THOMPSON: Uh-huh.
25 CHAIR BLEY: -- as your slide shows, than NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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108 1 the 300 kilometers, then you ought to be looking 2 further away than that for a source.
3 DR. CORRADINI: But her point --- I 4 thought her point was that all the --- yeah, all the 5 volcanic hazards have to be individually assessed in 6 terms of distance out to --- not out to, beyond.
7 MS. THOMPSON: So, for surface hazards it 8 is the ---
9 DR. CORRADINI: Okay.
10 MS. THOMPSON: -- 200-mile radius. For 11 ash fall hazards we extend it beyond as to what is 12 credible for that volcano and for the distance that 13 the ash fall ---
14 DR. CORRADINI: Okay. But you got to ---
15 MS. THOMPSON: -- could credibly travel.
16 DR. CORRADINI: -- find that volcano, 17 yeah.
18 MS. THOMPSON: And that's what you do in 19 Step 1.
20 DR. CORRADINI: Okay. That's where I'm 21 kind of hanging because in Step 1 it kind of says look 22 out to 300 ---
23 MEMBER DIMITRIJEVIC: Yeah.
24 DR. CORRADINI: -- kilometers.
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109 1 hazards. And then for ash fall ---
2 CHAIR BLEY: How far do you look?
3 MS. THOMPSON: -- consider further.
4 CHAIR BLEY: How far?
5 MS. THOMPSON: Well, that would be based 6 on site-specific considerations of volcanic sources 7 outside the 200-mile radius.
8 So, if you're looking ---
9 CHAIR BLEY: So, you've got to ---
10 MS. THOMPSON: So, if you're looking at a 11 site in Iowa ---
12 CHAIR BLEY: To do that, you have to find 13 them.
14 MS. THOMPSON: So, looking at a site in 15 Iowa, you would have to determine whether to extend 16 that region of interest to include Cascade volcanoes.
17 CHAIR BLEY: Yeah.
18 MS. THOMPSON: Could a Cascade volcano ash 19 fall reasonably arrive at a site in Iowa and --
20 CHAIR BLEY: In sufficient quantities of 21 matter.
22 MS. THOMPSON: -- in sufficient quantity 23 to affect a facility.
24 DR. CORRADINI: If you find a presidential 25 candidate under the ash --- sorry.
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110 1 MS. THOMPSON: So, for ash fault the 200-2 mile radius is extended to what is credible.
3 MEMBER DIMITRIJEVIC: To 300?
4 MS. THOMPSON: Huh?
5 MEMBER DIMITRIJEVIC: To 300.
6 MS. THOMPSON: Well, to what is credible.
7 MEMBER DIMITRIJEVIC: Well, this is what 8 we --- if my -- the volcano is further from 300, I 9 will screen it in Step 1.
10 That's what you are saying? That's what 11 I am trying to tell you.
12 PARTICIPANT: Just for surface hazards.
13 MS. THOMPSON: Just for surface hazards.
14 MEMBER DIMITRIJEVIC: Oh. So, now I have 15 to look again in all volcanoes even I determine it ---
16 PARTICIPANT: Some distance further.
17 MEMBER DIMITRIJEVIC: That doesn't make 18 any sense that I have to look in all the country 19 again. That's totally senseless.
20 MS. THOMPSON: Well, it's based on our 21 geologic knowledge of the volcanic sources. So, the 22 surface hazards we consider those closest to the 23 proposed site, which is the 200-mile radius.
24 Many of those surface hazards, you think 25 about a debris flow or a --
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111 1 MEMBER DIMITRIJEVIC: I understand you 2 completely.
3 MS. THOMPSON: Yeah. Okay.
4 MEMBER DIMITRIJEVIC: So, there are things 5 that we understand. Let's talk about what I don't 6 understand.
7 MS. THOMPSON: Okay.
8 MEMBER DIMITRIJEVIC: If I'm in Vogtle, 9 somewhere there is not any volcano on the site, right, 10 I'm already out in the first step because I don't have 11 anything within 200 miles. I'm out.
12 Why would I go on Step 2?
13 MS. THOMPSON: If you were at the Vogtle 14 site, you --
15 MEMBER DIMITRIJEVIC: Or on some site 16 there is --
17 MS. THOMPSON: Yeah.
18 MEMBER DIMITRIJEVIC: -- no volcano within 19 200 miles. I already exceed this process.
20 MS. THOMPSON: Mm-hmm.
21 MEMBER DIMITRIJEVIC: So, why would I go 22 now and check for ashes?
23 MS. THOMPSON: Because within Step 1 we're 24 looking at the 200-mile radius for surface hazards and 25 extending beyond that for the ash fall hazard.
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112 1 MEMBER DIMITRIJEVIC: But do you 2 understand if I am not within 200 miles of any 3 volcano, I will already exceed in the first step and 4 say no and here I am. I will never go to Step 2.
5 MEMBER REMPE: So, Vesna, if you look at 6 Slide 23, she's got two things. You got to go for not 7 only the surface hazards, you also got to look for ash 8 fall. You're not out of it.
9 MEMBER DIMITRIJEVIC: I understand all 10 these hazard perfectly. I already read that, I just 11 want to say I will never come to the Step 2.
12 CHAIR BLEY: You will. Read the text and 13 not the slide.
14 MEMBER DIMITRIJEVIC: Because I screen and 15 I am not within 200 miles.
16 MEMBER REMPE: The text for Step 1 --
17 MS. THOMPSON: I'm looking at Slide 23 and 18 I don't see that.
19 MEMBER DIMITRIJEVIC: Okay.
20 MEMBER REMPE: Yeah, but the slides are 21 cartoons for us. The text says, look out to 320 22 kilometers for --
23 MS. THOMPSON: And then we say we should 24 extend that distance -- extend a sufficient distance 25 beyond 200 miles to encompass those Quaternary NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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113 1 volcanic systems that have the potential to effect the 2 design or operation of the proposed reactor.
3 CHAIR BLEY: So, just a simple question 4 that would help us get our arms around how far away do 5 you look.
6 When you get a giant volcano that puts 7 stuff up in the stratosphere, it messes up the air 8 everywhere, but you don't get substantial amounts of 9 ash coming down anywhere.
10 In Mount St. Helen's, for example, it 11 lofted over much of the State of Washington ---
12 MS. THOMPSON: Uh-huh.
13 CHAIR BLEY: -- and fell in large 14 quantities out -- getting toward the Idaho border.
15 MS. THOMPSON: Uh-huh.
16 CHAIR BLEY: There must be some level of 17 experience to say you never have to look beyond 300 18 miles, 500 miles, something like that.
19 MS. THOMPSON: So, I'm actually --- I see 20 Britt holding the microphone again.
21 CHAIR BLEY: Or do you have to look 22 everywhere and then say for that particular volcano, 23 can the ash --
24 MS. THOMPSON: Well, you don't need to 25 look everywhere. We're looking at finding a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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114 1 reasonable distance based on the system-specific 2 characteristics of that particular volcano and that 3 particular site.
4 CHAIR BLEY: That volcano is the one you 5 have to find. That's why we're being a pest on it.
6 MS. THOMPSON: Okay. But did you have 7 more to add?
8 DR. HILL: We are trying to implement this 9 in a risk-informed framework and we're faced with an 10 information gap and having no real good understanding 11 about what's the minimum level of ash that could 12 affect the design and safe operation of any proposed 13 facility.
14 Now, if we had a technical basis to say 15 that, yeah, we are looking at one millimeter of ash 16 with a threshold below which we'd have no structures, 17 system or component that's important to safety would 18 be adversely perfected by the presence of one 19 millimeter of ash.
20 If we had that, we could develop some sort 21 of a more prescriptive screening criteria that said 22 credibly for US volcanoes X distance away seems very 23 unlikely to produce one millimeter of ash.
24 Unfortunately, we don't have that sort of 25 a design basis.
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115 1 DR. CORRADINI: But can't you work the 2 problem backwards?
3 Instead of worrying about how the source 4 loss -- this whole thing, ask the question for 5 structure, systems and components, at what point would 6 they start not performing.
7 DR. HILL: That's an excellent question.
8 We just don't have the technical information from --
9 either in the US or around the world to make an 10 informed decision about that.
11 CHAIR BLEY: They didn't have systems 12 people --- oh, go ahead.
13 MEMBER DIMITRIJEVIC: But wouldn't the 200 14 miles be enough for one millimeter of ash?
15 DR. HILL: No, it would not.
16 MEMBER DIMITRIJEVIC: The only --- the 17 most --- I mean, you know, I don't think that the ---
18 I mean, you may lose offsite power, but we can say 19 that in data of loss of offsite power already.
20 I don't think the less than one millimeter 21 will affect anything, but we --- you know, subsystem 22 people can look at that.
23 That means different facility design, 24 right?
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116 1 sucking air through a big pump to make them work.
2 CHAIR BLEY: ISFSIs you plug up all the 3 vents.
4 MEMBER MARCH-LEUBA: Yeah.
5 CHAIR BLEY: You don't have natural 6 circulation anymore.
7 MEMBER MARCH-LEUBA: When we were in the 8 Framatome enrichment facility where they dump, I don't 9 know, a foot of ash at Mount St. Helens, they showed 10 us everything they put on their systems and they have 11 these oil filters that they have to replace every 12 three hours if there is a --
13 MEMBER DIMITRIJEVIC: But this complicates 14 things so much more. It's just unbelievable because 15 a screening becomes so --- you know, just in these 16 first two locations screening becomes totally ---
17 MEMBER MARCH-LEUBA: If I was designing --
18 -
19 MEMBER DIMITRIJEVIC: -- unpractical.
20 MEMBER MARCH-LEUBA: -- the plant, what 21 would be useful for me would be you tell me how much 22 ash is going to fall in my site. And then I'll design 23 the field just to protect against that.
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117 1 it. If is half a millimeter, I may.
2 DR. HILL: And that is incredibly 3 straightforward problem to look at. Once you know 4 these are the volcanoes we have to consider, these 5 events, eruptive record, the science is sufficient to 6 do very good supportable modeling that can give you an 7 exceedance probability that counts for not only a 8 thickness being exceeded, but the annual likelihood of 9 it occurring due to eruption frequency, but that's a 10 more detailed analysis. It doesn't occur at the 11 screening stage.
12 MEMBER MARCH-LEUBA: But I cannot tell you 13 what my plant will be able to support because I 14 haven't decided yet.
15 If I put oil filters, I can support ten 16 times more.
17 DR. HILL: Yeah.
18 MEMBER MARCH-LEUBA: So, I think that from 19 a designer point of view, I want to know what I have 20 to design my diesel generators against, and then make 21 a decision can I make it or not, or is it not 22 workable, it's not economical to do it.
23 MS. THOMPSON: And I ---
24 MEMBER MARCH-LEUBA: You can filter 25 everything.
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118 1 MS. THOMPSON: And I think something that 2 you touched on is you said that knowing for your 3 design, and this approach is designed for siting.
4 So --- and when it comes to design 5 factors, that will come in at a later step. But if 6 you were using this for design, you would still go 7 through this process to determine your design 8 characteristics --
9 MEMBER MARCH-LEUBA: There is something --
10 MS. THOMPSON: -- but you would still have 11 to do the siting consideration as well.
12 MEMBER MARCH-LEUBA: There is something 13 wrong with the approach. I cannot --- you cannot give 14 me criteria for siting if you don't know what I'm 15 putting there.
16 If I have --- if I'm driving a car into a 17 stream, okay, and I'm driving my car into a stream, I 18 can go in the stream this deep because the water will 19 start getting into the carburetor --- not that anybody 20 has carburetors anymore.
21 If I'm driving a high car with an intake 22 out here, I can drive into a stream that is this tall.
23 So, the issue of siting depends on what car I'm 24 driving.
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119 1 generators --
2 DR. HILL: Wait a minute. But the same ---
3 MEMBER DIMITRIJEVIC: But the main comment 4 is you cannot screen from the first step. It maybe 5 makes sense for you guys to combine both steps.
6 DR. CORRADINI: Well, I think -- I thought 7 that's what -- I'm sorry, now I've forgotten -- you 8 keep identifying yourself for --
9 MS. THOMPSON: Britt.
10 DR. CORRADINI: Britt, I thought that's 11 what you were saying, this is a screening first step.
12 You might have to do a more detailed one as you go 13 down two or three levels in the ---
14 MEMBER DIMITRIJEVIC: No. No. Already 15 here, they cannot screen based on 200 miles.
16 DR. CORRADINI: No. 200 miles is specific 17 ---
18 (Simultaneous speaking.)
19 MEMBER DIMITRIJEVIC: -- your screening 20 make that one step, yeah.
21 MS. THOMPSON: Okay.
22 DR. CORRADINI: If it's quiet, start 23 going.
24 MS. THOMPSON: Okay.
25 (Laughter.)
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120 1 MEMBER DIMITRIJEVIC: Yeah, you can grab 2 that chance.
3 MS. THOMPSON: Yes. All right.
4 MEMBER RICCARDELLA: Kind of making an 5 analogy to seismic, you know, it seems like we have a 6 seismic hazard -- something like a hazard probability 7 curve, but we don't have a fragility curve to compare 8 that against.
9 We need to -- maybe people need to do some 10 volcanic qualification testing of various types of 11 equipment.
12 (Laughter.)
13 MS. THOMPSON: So, if after performing ---
14 (Simultaneous speaking.)
15 MEMBER DIMITRIJEVIC: -- define safety 16 completely as ash-resistant.
17 MS. THOMPSON: So, if after performing the 18 deterministic screening the potential volcanic hazard 19 is determined to not present a credible hazard based 20 on some deterministic screening criteria or the 21 distance which the hazard could credibly travel from 22 the source and would not affect the site, an applicant 23 using this VHA would document their results and the 24 analysis is complete.
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121 1 Step 3 to consider initial risk insights. The initial 2 risk insights would include a suite of risk-informed 3 information, not just the plant's PRA, that would be 4 used to judge the safety significance of information.
5 This information may include the 6 sensitivity of the new information in the facility's 7 PRA, the degree of uncertainty in the new information, 8 the consideration of available alternatives and the 9 confidence in the supporting investigations.
10 For the initial risk insight step using 11 the plant's PRA, an applicant could assume that the 12 probability of an SSC failure or unacceptable 13 performance would be equal to one if the screened-in 14 volcanic hazard occurs at the site.
15 They would then evaluate the results in 16 the PRA and consider additional risk insight 17 information.
18 This would help to determine if the 19 volcanic hazard is significant to safety with no 20 credit for the likelihood or magnitude of occurrence 21 of that hazard.
22 If the insights show that the risk or the 23 hazard is not significant, the applicant would 24 document the rationale and complete the VHA.
25 Otherwise, they would proceed to the next step.
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122 1 DR. CORRADINI: So, basically the 2 consequence is failure.
3 MS. THOMPSON: Yes.
4 MEMBER DIMITRIJEVIC: This is where it's 5 important to add the SSC susceptible to identify 6 hazard.
7 MS. THOMPSON: Okay.
8 MEMBER DIMITRIJEVIC: If you put all SSCs 9 to be one, then, I mean, you know, you are just going 10 to --
11 DR. CORRADINI: You're done.
12 MEMBER DIMITRIJEVIC: Yeah, you're done.
13 So, that's why it's very important to 14 understand susceptibility, you know.
15 MS. THOMPSON: Yes. I think that's a key 16 clarification to make.
17 CHAIR BLEY: But with all due deference to 18 my colleagues here, some hints about what kinds of 19 structures, what kinds of components are susceptible 20 to what kinds of ---
21 PARTICIPANT: Examples.
22 CHAIR BLEY: -- hazards would be very 23 helpful. Otherwise, you know, it's --- you're asking 24 people for a rock. And when it comes in you'll say, 25 eh, it's the wrong rock, go do it again.
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123 1 MS. THOMPSON: Okay.
2 MEMBER DIMITRIJEVIC: So, it could be 3 table -- a table of hazard and what type of components 4 could be susceptible to that.
5 MS. THOMPSON: Okay. I'll take that note 6 back to ---
7 (Simultaneous speaking.)
8 MEMBER DIMITRIJEVIC: -- plant.
9 CHAIR BLEY: And that requires you to 10 having some PRA people and, more importantly, some 11 real plant people who know what things are where and 12 what they're vulnerable to.
13 MEMBER DIMITRIJEVIC: And in addition to 14 SSCs, there should be human actions also. Because if 15 you have to get rid of operators because they have to 16 evacuate.
17 MS. THOMPSON: Okay.
18 CHAIR BLEY: And when you get to Step 6 or 19 7, you have to model ---
20 MS. THOMPSON: And that's something that 21 we have, as a working group, included in the 22 mitigating actions is being able to demonstrate or 23 show that the actions are practicable given the 24 hazard. So, we'll get to that.
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124 1 that is significant to safety, they will proceed to 2 Step 4 where they will evaluate either the probability 3 of eruption, which is PE, or the probability of the 4 hazard reaching the site, which we call PH.
5 In a traditional VHA, an applicant would 6 calculate both of these probabilities; the probability 7 of the eruption and the probability of the hazard.
8 But in the draft guide --
9 MEMBER DIMITRIJEVIC: The frequency of 10 eruption. Frequency of eruption, probability of 11 hazard.
12 That's a very important distinction 13 because eruption doesn't have a probability. It has 14 a frequency.
15 MEMBER BALLINGER: And shouldn't 16 evaluation of eruption be further up? Because if 17 there's no likelihood of an eruption, you're done, 18 right?
19 MEMBER DIMITRIJEVIC: What's the 20 probability to calculate that frequency accurately?
21 CHAIR BLEY: They've got an embedded 22 assumption that it's -- and they don't have PRA 23 people. They've got an embedded assumption that it's 24 easier to calculate the conditional probability of 25 core melt or release given failure of a set of SSCs NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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125 1 than it is to calculate either PH or PE.
2 And in a moment, Jenise will get to saying 3 whichever one's easiest to calculate, calculate that 4 one first and then see if you can pass, and then 5 calculate the other one.
6 So, that's kind of the ---
7 MEMBER DIMITRIJEVIC: Because it ---
8 CHAIR BLEY: -- assumption.
9 MEMBER DIMITRIJEVIC: You cannot say 10 probability of this eruption is one in million. What, 11 within a year, within ten years, within the next 12 thousand years, next million years. That's why it's 13 frequency. You cannot give probability.
14 However, you can tell probability of ash 15 getting in a given eruption because that's an event.
16 So, it's probability.
17 MS. THOMPSON: Okay.
18 MEMBER DIMITRIJEVIC: So, the various 19 frequency event. If you want to call it probability 20 for PE, you can say per year. Probability per year 21 and then it's the -- you know, then you are sort of 22 calling probability, but it's actually closer to 23 frequency.
24 MS. THOMPSON: All right. So, in the 25 draft guide the staff allows for the applicant to use NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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126 1 -- or to calculate either PE or PH first, and then use 2 risk insights to determine if additional probability 3 calculations are warranted.
4 The justification for this is that the 5 staff recognizes that volcanic events, the character 6 of past volcanic events may be more certain than the 7 timing of these past volcanic events.
8 So, calculating PH, or the probability of 9 the hazard reaching the site, may produce results that 10 have lower uncertainties and, therefore, provide 11 higher confidence in any risk insight decisions that 12 are made based on that calculation.
13 CHAIR BLEY: I think -- I have to go back 14 and look real carefully. I think the guidance you 15 give the user on doing a simplified PRA given either 16 PE or PH is the same guidance you gave them before you 17 knew PE or PH. Then knowing this probability doesn't 18 help you.
19 So, I think you need to give a little more 20 thought to how you mix -- how you make use of this 21 frequency or this probability, whichever one you're 22 doing.
23 MEMBER DIMITRIJEVIC To make it risk-24 informed.
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127 1 simplified PRA, it probably needs to be a little more 2 than, you know.
3 And you get this somewhere, and somewhere 4 in there you imply if PH is small enough, you're done.
5 And then you say, and then if PE is small enough, 6 you're done.
7 MS. THOMPSON: So, if --
8 CHAIR BLEY: And if the product of the two 9 is small enough, you're done. And then you do a 10 simplified PRA to go with it if it's not small enough, 11 but you don't give people a hint of how they use that 12 risk measure that's coming out that has a frequency 13 and a probability of failure to make a decision.
14 MS. THOMPSON: So, I think we're going to 15 get to that. We don't have an option in the 16 calculation of PE and PH to end the analysis.
17 Once this step is completed, an applicant 18 proceeds into the detailed risk insights where --- I 19 will get to this, but PE and PH, or both, are assumed 20 in the PRA to equal failure.
21 So, we'll get to that in ---
22 MEMBER DIMITRIJEVIC: But a comment that 23 Dennis ---
24 MS. THOMPSON: -- Step 5.
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128 1 to --
2 MEMBER RICCARDELLA: Is PH a conditional 3 probability?
4 MEMBER DIMITRIJEVIC: Yes.
5 MEMBER RICCARDELLA: Conditional 6 probability given ---
7 MEMBER DIMITRIJEVIC: Conditional 8 probability given eruption.
9 MEMBER RICCARDELLA: -- eruption. All 10 right.
11 CHAIR BLEY: And given the hazard you're 12 talking about.
13 MEMBER DIMITRIJEVIC: Right. And given 14 the hazard.
15 CHAIR BLEY: You have to do it for each 16 hazard.
17 MEMBER DIMITRIJEVIC: Jenise ---
18 MS. THOMPSON: Yes.
19 MEMBER DIMITRIJEVIC: -- what Dennis is 20 proposing, and this is how we become risk-informed, 21 you can also exit here if frequency of that occurs 22 once in hundred million years and, you know, it will 23 be a probability or hazard combined if that is smaller 24 than once in ten million years, you can exit here. No 25 need to go --
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129 1 DR. CORRADINI: But I guess I'm kind of 2 with them. You would have never gotten this far if 3 what you just said is true because you already have 4 the time period and you already have the magnitude.
5 MEMBER DIMITRIJEVIC: But you know the 6 time period is 2.6 million years.
7 DR. CORRADINI: Yeah. So, it's already 8 been screened in based on that.
9 MEMBER DIMITRIJEVIC: Well, in that case 10 it can be screened out from the -- you know, a lot of 11 PRA --
12 DR. CORRADINI: But if the frequency of 13 eruption is --
14 CHAIR BLEY: You don't have the frequency 15 of eruption yet until you calculate this.
16 DR. CORRADINI: Oh.
17 MS. THOMPSON: That's the step we're at.
18 DR. CORRADINI: So, I apologize. I know 19 we're taking you off track, but you can save this one.
20 I want to know the level of when you fall out, whether 21 it's FE or PH or the product of FE and PH.
22 How low does it have to get when it 23 essentially says it's so low it's residual risk?
24 MS. THOMPSON: That --
25 DR. CORRADINI: I didn't find that.
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130 1 MS. THOMPSON: So, that's because it's not 2 in there. So, we didn't provide a "this is your 3 limit."
4 There isn't a limit in here because we're 5 using the risk insights to create a risk-informed 6 approach to this volcanic hazards assessment.
7 DR. CORRADINI: But now that I'm risk-8 informed, at some point I can ignore the risk because 9 it's so small as to be residual.
10 MS. THOMPSON: Correct. And that's in 11 going through the steps.
12 So, once we get into Step 5, the detailed 13 risk insights, that's where, as I mentioned before, 14 we're using the facility PRA to assume that PE, PH, or 15 both of them equal failure. And so, that is where 16 that stuff would be.
17 And if those results are not significant, 18 then an applicant would complete the analysis.
19 DR. CORRADINI: Okay. But that's what I'm 20 trying to understand -- if you tell me to wait, I'll 21 wait. Is there you're going to tell me what's 22 significant and what's not significant?
23 MS. THOMPSON: We don't have that 24 threshold in the draft guide.
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131 1 you a threshold.
2 You already have a licensing modernization 3 program that says anything below 5, 10 to the minus 4 7th is residual risk.
5 Seems to me if this falls below 5, 10 to 6 the minus 7th of the thing, I ignore it.
7 CHAIR BLEY: They don't have that process 8 yet.
9 MEMBER DIMITRIJEVIC: No. That's not part 10 of ---
11 DR. CORRADINI: But if it's one of the 12 external hazards --- if it's one of the natural 13 external hazards you have to calculate anyway for 14 advance reactor, it's automatically in there based on 15 the logic of the LMP.
16 CHAIR BLEY: The LMP isn't real yet.
17 DR. CORRADINI: Well, it's getting close.
18 MEMBER RICCARDELLA: The LMP isn't what 19 yet?
20 CHAIR BLEY: Real.
21 DR. CORRADINI: Well, I thought commission 22 was approving it.
23 CHAIR BLEY: I certainly haven't heard 24 that -- no, I heard yesterday that they have not yet.
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132 1 that's where I was going, but thank you.
2 MS. THOMPSON: Okay.
3 DR. CORRADINI: Thank you very much.
4 MS. THOMPSON: So, in --
5 MEMBER DIMITRIJEVIC: It's extremely 6 important actually for you guys since you are the PRA 7 people, when you are having risk-informed application, 8 doing PRA is last step.
9 So, you cannot really screen it through 10 the PRA because you are already doing PRA which is 11 very complex model.
12 So, you will try to screen it like 13 assuming everything failed, which is alright. But 14 normally when you failing everything, you have to have 15 some frequency of the "when" to analyze that.
16 Because if you are failing everything with 17 frequency of one, it's different than when you're 18 failing everything frequency of ten.
19 So, this type of thinking has to come 20 somewhere through, you know.
21 MS. THOMPSON: Okay.
22 MEMBER DIMITRIJEVIC: Because if you fail 23 everything and nothing happen, that's only way you can 24 screen, actually, if you fail everything in the ---
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133 1 the plant because you don't have a frequency.
2 So, screening --- I understand uncertainty 3 the frequency is -- I don't want to think about, I 4 have no clue, you know. It will be equally as 5 unlikely of predicting future volcanoes, but --- so, 6 it was very difficult, but maybe we can have some 7 threshold for definitely is not bigger than ten to the 8 minus four for the screening purpose or something.
9 MS. THOMPSON: Okay. I'll take that note 10 back to the working group. I'll take that note back.
11 MEMBER BROWN: How can you do all this 12 stuff that you're all talking --- no, not --- this is 13 a general question.
14 How can you do all this stuff when you 15 don't --- early site permit, you don't even know what 16 the plant's going to look like, and how do you screen 17 out a site without going through all this rigmarole.
18 I mean, is there a 100-mile radius from an 19 active -- a potentially active site? You say if 20 you're outside of 100-mile or 200-mile radius and you 21 just don't do any of it?
22 I'm just listening to the discussion and 23 worried that you apply this and we'll never build 24 another plant anywhere.
25 MS. THOMPSON: So --
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134 1 MEMBER BROWN: It just -- it's becoming 2 complex, you got to do this, you got to have 3 probabilities to this and that and everything else.
4 You'll never get there.
5 DR. SCHULTZ: It also seems like --
6 MEMBER BROWN: I'm being somewhat of a 7 skeptic right now.
8 DR. SCHULTZ: It also seems that rather 9 than have every applicant get started on Part 1, that 10 it could be done geographically across the United 11 States to identify places where vulnerabilities might 12 be important ---
13 MEMBER BROWN: Yeah. Exactly.
14 DR. SCHULTZ: -- and get that done right 15 off the bat --
16 MEMBER BROWN: Exactly.
17 DR. SCHULTZ: -- so the map for Nos. 1 and 18 2 --
19 MEMBER BROWN: There's nothing that says, 20 how can I avoid this? One way of phrasing it.
21 DR. SCHULTZ: -- so that geologists don't 22 have to be hired by every applicant.
23 MEMBER BROWN: Exactly.
24 DR. SCHULTZ: I mean, the applicants you 25 had come to the meeting from the public sounded like NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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135 1 they were the developers.
2 MS. THOMPSON: We also had several ---
3 DR. SCHULTZ: Geologists?
4 MS. THOMPSON: -- on the phone that were 5 doing siting.
6 DR. SCHULTZ: Geologists?
7 MS. THOMPSON: They're geologic 8 consultants.
9 DR. SCHULTZ: Uh-huh.
10 MS. THOMPSON: I'm not sure what their job 11 title is, but I have interacted with them in the past 12 in the capacity of ---
13 DR. SCHULTZ: It seems like that could be 14 ---
15 MS. THOMPSON: -- being a geologist at the 16 site.
17 DR. SCHULTZ: -- a onetime thing for the 18 United States and not an individual applicant's task 19 ---
20 MEMBER BROWN: Well, that's similar ---
21 DR. SCHULTZ: -- to get started, but.
22 MEMBER BROWN: I mean, with the seismic 23 when we do the ESPs, there's a --- the seismic issues 24 get addressed right up front based on the 25 configuration of ---
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136 1 DR. SCHULTZ: Correct.
2 MEMBER BROWN: -- land --- and you can do 3 that without knowing what the plant looks like. Here, 4 when you start --- are we going to just do safety 5 systems or is it everything on the plant site?
6 I mean, where do you screen --- where do 7 you draw that line?
8 PARTICIPANT: They're doing boundary 9 analysis up ---
10 MEMBER RICCARDELLA: But seismically you 11 just come up with a ---
12 MEMBER BROWN: Not with the PRAs you-all 13 want to do --- not that we're proposing.
14 PARTICIPANT: So, you're just ---
15 CHAIR BLEY: You're jumping way ahead of 16 yourself.
17 MEMBER BROWN: I'm just looking at 18 complexity and how do we ever get started.
19 CHAIR BLEY: It's not there yet.
20 MEMBER BROWN: Seismically it seems like 21 there's a process to go through for an early site 22 permit.
23 This sounds like another one of those 24 things where you want to try to discount it 25 immediately off the bat that you don't have a problem.
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137 1 MEMBER RICCARDELLA: But seismically it 2 just comes up with a response spectra that you're 3 going to use that that's ---
4 MEMBER KIRCHNER: That's fine if you have 5 firm ground to design against.
6 MEMBER BROWN: You wouldn't build a plant 7 on the San Andreas Fault today. Regardless of what 8 you did with your seismic spectra, you would not build 9 one.
10 So, we did it the old days, but we 11 wouldn't do it today.
12 MEMBER BALLINGER: But in this case you 13 would have like a two-map problem. The eruption 14 problem is a good enough -- one you can do, but the 15 ash/plume problem, that's a different story.
16 MEMBER BROWN: But even that in the past 17 circumstances has been 100 miles ---
18 MEMBER BALLINGER: I don't know.
19 MEMBER BROWN: -- 150 miles.
20 CHAIR BLEY: We know more now.
21 MEMBER DIMITRIJEVIC: Charlie, let's not 22 be negative. They're trying to do something good.
23 MEMBER BROWN: No, I'm just -- I'm worried 24 --- I think the good is often the --- something nasty 25 for okay. And I'm not hearing any okay. It's just NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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138 1 more analysis and more details.
2 CHAIR BLEY: I've heard several okays. If 3 there's no volcano near enough, it's okay. If there's 4 no volcano in the area ---
5 MEMBER BROWN: I would never --
6 MS. THOMPSON: I would also add that for 7 geologic site ---
8 (Simultaneous speaking.)
9 MEMBER BROWN: I'd like to read the 10 transcript on this meeting.
11 MS. THOMPSON: So, for geologic site ---
12 MEMBER BROWN: I will, you won't.
13 MS. THOMPSON: -- characterization for 14 non-vocalic hazards for ESPs, the staff does have 15 experience with revisiting things once a site --- once 16 a site has been approved and after a technology has 17 been selected at the COL stage.
18 So, if we're in that position with respect 19 to volcanic hazards, it would not be unprecedented for 20 the staff to assess what can be assessed at the ESP 21 stage and defer what reactor or design-specific 22 information needs to be assessed at the more detailed 23 COL stage. So, there is that possibility.
24 PARTICIPANT: Jenise ---
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139 1 thought that I didn't say. I went through --- I read 2 the draft ---
3 MS. THOMPSON: Uh-huh.
4 MEMBER BROWN: -- and one of the things I 5 noted here was ---
6 PARTICIPANT: Charlie, is your mic on?
7 MEMBER BROWN: Oh, I'm sorry. I read he 8 draft and I --- the only words I ever saw were "safety 9 significance," not you need to take care of safety 10 systems, those necessary to take --- to shut down the 11 plant, put it in a safe condition.
12 It was -- the "safety significance" had a 13 broader context, in my opinion, as I read through the 14 draft.
15 So, to me, our focus ought to be on 16 shutting the plant down, safe condition, what are the 17 systems needed?
18 Those are the ones you -- you know, you 19 start screening for the "how do you do that" or 20 whatever it is. That's -- that was -- that's just a 21 thought, that's all.
22 And Mike's going to disagree with me again 23 because he doesn't like projectiles going --
24 DR. CORRADINI: I don't think they're at 25 the system stage yet. I'm not sure --
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140 1 MEMBER BROWN: I'm just saying the reg 2 guide ought to provide a second level of screening 3 relative to saying, what do we expect them to look at 4 once they get there.
5 DR. CORRADINI: Okay.
6 MEMBER BROWN: That's all I'm trying to 7 say. It doesn't say that right --- it's very, very 8 broad.
9 MS. THOMPSON: Okay. And I made a note of 10 that here.
11 MEMBER KIRCHNER: Jenise ---
12 MS. THOMPSON: Yes.
13 MEMBER KIRCHNER: -- it seems to me, 14 though, that the problem really is not the surface 15 phenomena, but this ash issue because it could come 16 from anywhere, you know.
17 So, my question to you and the experts, 18 and I guess this would involve your meteorologist as 19 well, are there any maps that they've -- kind of rules 20 of thumb or something where they look at a volcano as 21 putting this much material in the air?
22 What are the dispersion characteristics?
23 Are there, you know, like plume maps or something that 24 would allow you to screen against that is more than --
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141 1 ever put up a lot of ash in the air ---
2 MS. THOMPSON: I believe that there ---
3 MEMBER KIRCHNER: -- and sort that out.
4 MS. THOMPSON: -- there are plume maps 5 available. I'm not sure to what extent they're 6 available for every volcano that may be within ---
7 MEMBER KIRCHNER: No, but I ---
8 MS. THOMPSON: But I know that ---
9 MEMBER KIRCHNER: -- I would think that --
10 -
11 MS. THOMPSON: -- there are maps that 12 could be used. And that would be something that would 13 inform the deterministic screening in Step 2.
14 MEMBER KIRCHNER: But I'm still having a 15 problem with this because it seems to me there's 16 infinite variability out there in terms of how you do 17 a cutoff on where to expect the ash fall to be.
18 So, where I was going is, are there enough 19 -- has there been enough experience mapping the output 20 and results of a volcano to understand that, you know, 21 this deposition of ash is a 400-mile phenomenon, is it 22 -- whatever, you know.
23 So, it seems to me anything --- any 24 guidance along those lines would leave it less open-25 ended about what --- how many volcanoes from --- how NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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142 1 many sources --- do we have to worry about Iceland 2 volcanoes when we site a plant in the US?
3 My intuition says no ---
4 MS. THOMPSON: And that's a good ---
5 MEMBER KIRCHNER: -- but is ---
6 MS. THOMPSON: That's a good segue.
7 (Laughter.)
8 MS. THOMPSON: There are dispersion maps.
9 One of the ways that a lot of this can be addressed 10 and reach consensus on what is credible, what is not 11 credible, is through using the SSHAC process, which we 12 mentioned before.
13 The SSHAC process, the goal is to 14 determine the center body and range of the technically 15 defensible interpretations.
16 So, using the SSHAC process to consider 17 the extent to which ash fall should be considered from 18 a volcano 200 miles away versus 500 miles away could 19 be resolved using the expert elicitation in the SSHAC 20 process.
21 DR. SCHULTZ: Jenise, when does that get 22 done? I mean, you can't lay that process on top of 23 every licensee that is considering siting a nuclear 24 plant.
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143 1 is where --
2 DR. SCHULTZ: Yes, my light is on.
3 MS. THOMPSON: This step using the SSHAC 4 process is included in Step 4 specifically for 5 calculating the PE and PH -- so, the probability of 6 eruption or the frequency of eruption -- and the 7 probability of the hazard reaching the site.
8 So, if at this point you do have ash fall 9 as a hazard that you are considering, the SSHAC 10 process would help you determine what would be the 11 credible range for that ash fall.
12 MEMBER KIRCHNER: Can you move this up?
13 Because if you make the analogy with seismic hazards 14 analysis, you start almost right away with maps of the 15 seismic zones that you're in and then go from there.
16 Doing this so late in the process seems, 17 to me, to drive, as Charlie was concerned, a lot of 18 uncertainty, which opens you to a lot of intervention 19 and a lot of wasted effort if indeed you would screen 20 out with this step in the SSHAC process.
21 MEMBER DIMITRIJEVIC: I have a proposal.
22 I think that you should stay in 200 miles. That's it.
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144 1 blah, blah, blah, then, blah, blah, blah, the next 2 thing can be done.
3 Just stay in 200 miles, screen off the 200 4 miles, say that that's also things for ash, and then 5 have some paragraph to address if the specific design, 6 you know, is expected to be susceptible to ash-related 7 failure do additional analysis.
8 MEMBER BALLINGER: But isn't there a 9 parallel to this in severe accident analysis?
10 MEMBER KIRCHNER: No.
11 MEMBER BALLINGER: Don't we look at ---
12 PARTICIPANT: But there is a parallel in 13 seismic.
14 MEMBER BALLINGER: -- distributions of 15 wind and everything if we get a large, early release.
16 CHAIR BLEY: You have to analyze that.
17 I want to remind you of something I said 18 in the very beginning. The ACRS only speaks through 19 its letters.
20 (Laughter.)
21 CHAIR BLEY: You're hearing a bunch of 22 comments from individual members.
23 DR. CORRADINI: Yeah. So, don't write it 24 down necessarily.
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145 1 skeptics.
2 MEMBER MARCH-LEUBA: Let me qualify that.
3 You hear a bunch of uninformed comments.
4 (Laughter.)
5 MEMBER DIMITRIJEVIC: Everybody is very 6 opinionated.
7 CHAIR BLEY: And perhaps some informeds.
8 MS. THOMPSON: I'm just making notes of --
9 -
10 CHAIR BLEY: Grain of salt.
11 MS. THOMPSON: -- some of the pertinent 12 points that you're making because not all of our 13 working group members are here today. So, I want to 14 be able to convey what the full scope of the 15 discussion was to them as well.
16 PARTICIPANT: You can get a copy of the 17 transcript, also.
18 MEMBER KIRCHNER: It seems to me that if 19 you move this up --
20 MS. THOMPSON: Uh-huh.
21 MEMBER KIRCHNER: I'm wearing my hat as a 22 reactor designer. I'm not going to spend a lot of 23 money on oil filters and such unless I really convince 24 myself I have the hazard.
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146 1 against this particular hazard, I need to do this ash 2 fall analysis first.
3 Otherwise, I'm wasting my time because I 4 may design something and it may turn out to be 5 inadequate if I do the ash fall analysis later in the 6 process.
7 A lot of these advanced reactors are 8 cartoons early on. So, they may want to have a site 9 chosen, but they are not going to have the maturity to 10 do a full-blown PRA that shows them how vulnerable 11 they are to these kind of threats.
12 MS. THOMPSON: I will say that the SSHAC 13 process, we put it here in the presentation because we 14 recommend it for calculating PE and PH.
15 There's nothing in the draft guide that 16 would preclude an applicant from deciding to use a 17 SSHAC-like process to perform their deterministic 18 screening or even their initial characterization of 19 potential sources of volcanism.
20 So, the SSHAC could be used at any step 21 and I don't even think we listed it in the draft 22 guide. It's not even in the steps.
23 It's listed separately so that the SSHAC 24 process can be used at any step along the way to 25 inform the process.
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147 1 And maybe that's not clear in the draft 2 guide, but the SSHAC process could be used at any step 3 along the path.
4 DR. CORRADINI: I guess -- so, another 5 opinion you could not write down, I like how you've 6 done it.
7 MS. THOMPSON: Okay.
8 DR. CORRADINI: I think if I were the 9 engineer that had to worry about this or decide not to 10 worry about it, I would think Steps 1 through 3 ought 11 to be done quickly and efficiently and only spend the 12 money on bringing in a bunch of high-priced experts 13 that aren't really sure what they are doing until I 14 really need to do it.
15 So, I like the fact that you've waited 16 until whatever step we're on ---
17 MS. THOMPSON: 4. We're on Step 4.
18 DR. CORRADINI: -- before you bring in 19 what could be a cadre of individuals ---
20 MS. THOMPSON: Right.
21 DR. CORRADINI: --- that have to kind of 22 chew this over.
23 MS. THOMPSON: And that was the working 24 group's perspective as well that an initial screening 25 would be a relatively quick process for an informed NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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148 1 geologist to do. The same thing with a deterministic 2 screening.
3 But once you get to looking at PE and PH, 4 this is where you need to reach a wider consensus 5 based on the hazards that you have at your site.
6 And I have some examples that I can share 7 with you in the next flew slides of why this is 8 important, and why at this particular step the SSHAC 9 would be particularly appropriate to be used.
10 So, I will move along.
11 CHAIR BLEY: Actually, just to put you 12 squarely, you talk about SSHAC before you get to the 13 methodology.
14 MS. THOMPSON: Yeah.
15 CHAIR BLEY: It's an introductory section.
16 MS. THOMPSON: Yeah. It's not in Section 17 3 --- or Section C ---
18 CHAIR BLEY: That's right.
19 MS. THOMPSON: -- with the actual guidance 20 itself. It's separate. So, it can be used at any 21 step along the way.
22 So, one of the key challenges with the 23 probability of eruption --- or the frequency of 24 eruption would be defining what is an event.
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149 1 from the 1955 eruption on the Kilauea East Rift. This 2 eruption occurred over an 88-day period along a 15-3 kilometer rift with four major vents.
4 Because of direct observation, we know 5 that this was one event. But if this event had 6 occurred 100,000 years ago, it may not be as clear 7 based on the available data.
8 So, we would need to reach a consensus 9 within the VHA of what constitutes an event and how 10 each event would be interpreted.
11 Would this 1955 eruption be considered one 12 large event along four events effecting about 50 13 square kilometers, or would we consider this instead 14 to be four separate events?
15 The point is that the SSHAC process would 16 allow us to reach a consensus on what is considered an 17 event and then to ensure that that event definition is 18 applied consistently across the analysis.
19 Additional challenges with calculating the 20 PE include reaching a consensus on the goal, whether 21 we are looking for the probability of occurrence, the 22 probability of exceedance or both.
23 MEMBER DIMITRIJEVIC: How would you know 24 this was something happened million years ago?
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150 1 that within the SSHAC process.
2 PARTICIPANT: Called educated guessing.
3 CHAIR BLEY: You'd look at what material 4 is coming out, is it ---
5 MS. THOMPSON: Yes.
6 CHAIR BLEY: -- the same character all the 7 way along.
8 MS. THOMPSON: Yes. So, we would have to 9 look at the characteristics. We would look at field 10 interpretations. We could look at laboratory test 11 results.
12 There are a number of ways to characterize 13 past volcanic events and reaching consensus on how 14 similar does something need to be to be considered the 15 same event.
16 Additional uncertainties may be associated 17 with the timing and number of past events. And then 18 volcanic systems have the potential for non-stationary 19 recurrence rates.
20 So, the SSHAC process would also help 21 reach a consensus on what period of a volcano's 22 history should be considered representative of its 23 future potential activity.
24 We also see similar challenges in the 25 calculation of the probability of the hazard, or PH.
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151 1 The example here is from modeling data, which is the 2 key challenge in the calculation of PH.
3 There's a general lack of accepted models 4 and there's also a need for robust model support. The 5 examples shown here are three different models of 6 pyroclastic flows on the Soufriere Hills volcano on 7 Montserrat. This was a 1997 eruption.
8 The black line outlines the actual 9 pyroclastic flow. The colored areas represent the 10 modeled areas for the pyroclastic flow.
11 And, as you can see, each model captures 12 some part of the flow relatively well, but there are 13 significant differences in places where the 14 pyroclastic flow was not adequately captured by each 15 model.
16 So, this is an illustration of the need 17 for the SSHAC process to evaluate these models to 18 determine which of them appropriately capture the 19 hazardous aspects of the volcanic phenomena that may 20 affect a site.
21 It also emphasizes the need for model 22 support so that the model uncertainties are 23 appropriately captured.
24 MEMBER RICCARDELLA: Where was -- you 25 mentioned where this --
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152 1 MS. THOMPSON: This is the Soufriere Hills 2 volcano in Montserrat. It's a Caribbean island.
3 MEMBER RICCARDELLA: Oh, okay.
4 MEMBER KIRCHNER: Just for scaling 5 purposes, how many kilometers or miles are we looking 6 at in each box?
7 MS. THOMPSON: Oh, I think I cut the scale 8 off. Do we -- do you have the scale for this?
9 MEMBER KIRCHNER: It's not a big island.
10 DR. HILL: It's roughly 10 kilometers from 11 the source out to the northeast.
12 MEMBER KIRCHNER: That's what I was 13 saying.
14 So, here's an example where common 15 engineering sense would just tell you, I'm not going 16 to try and accurately model for these flows, I'm going 17 to stay outside a 10-kilometer radius and move on.
18 MS. THOMPSON: And that's a decision that 19 an applicant using the VHA could choose to make.
20 MEMBER KIRCHNER: Yeah.
21 CHAIR BLEY: Now, you haven't told us, and 22 I think some people would be -- it might help, for 23 different geologic structures and zones there are 24 different kinds of eruptions that might occur.
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153 1 create a lot of ash, others are more likely to create 2 the other hazards.
3 MS. THOMPSON: Yes.
4 CHAIR BLEY: And you guys are able to --
5 I mean, it's not just a blind shot what's going --
6 MS. THOMPSON: Yeah.
7 CHAIR BLEY: -- to come out of the ground 8 at a particular ---
9 MS. THOMPSON: And that's a very good 10 point. Volcanic systems, while dynamic, they are also 11 variable depending on the setting.
12 Not every volcano is going to erupt a 13 pyroclastic flow. Not every volcano is going to 14 result in, you know, ash that reaches the 15 stratosphere.
16 So, that setting is something that will be 17 considered early on and the different volcanic hazards 18 are what will be considered at the deterministic 19 screening.
20 So, if you have a -- let's say you have 21 the Eastern Snake River Plain. If you have a basaltic 22 volcano source, you're probably not going to be 23 looking at catastrophic pyroclastic flows off of that 24 volcano source.
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154 1 likely will not have any geologic evidence supporting 2 of a pyroclastic flow occurring in that location. So, 3 you could screen that out very early on in the 4 process.
5 CHAIR BLEY: Uh-huh.
6 MS. THOMPSON: But if you get to a point 7 here where you have specific volcanic hazards that are 8 likely to occur given the volcanic setting, then we 9 could use this process.
10 But that's a good point to make that the 11 hazards that I mentioned at the start are not a 12 comprehensive list that must be considered for every 13 location.
14 They are very site-specific and geologic-15 specific to what the processes that are driving 16 volcanism, which is why we consider that tectono-17 magmatic model at the very first step.
18 MEMBER KIRCHNER: So, I hate to regress, 19 but you do have some examples and Columbia is one.
20 Maybe there were no other plants in a direct 21 atmospheric flow pattern downstream of Columbia at 22 reasonable distances, but why was -- why were not 23 other commercial plants -- I don't know, I'll say 24 something ridiculous -- in Wisconsin required -- were 25 they -- when you decide that Columbia had issues with NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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155 1 ash fall, why did that not have a much larger radius 2 of impact -- what do you call it?
3 MS. THOMPSON: Region of interest?
4 MEMBER KIRCHNER: Region of interest, 5 yeah.
6 MS. THOMPSON: Again, this would be 7 looking at the geologic information. If there is a 8 credible level of geologic information that would 9 suggest that ash falls from, let's say, a Cascade 10 volcano, would reach a facility in Wisconsin, then 11 that would be considered.
12 If there's not geologic information to 13 support the likelihood that there would be significant 14 ash fall deposits at a site, then that would screen 15 out.
16 MEMBER KIRCHNER: But I would wager that 17 what happened historically with the agency was even 18 though Columbia had to deal with a consideration of 19 ash fall ---
20 MS. THOMPSON: Uh-huh.
21 MEMBER KIRCHNER: -- the agency did not 22 ask the Midwest plants to worry about ash fall, that 23 I recall.
24 DR. CORRADINI: They made a judgment.
25 MS. THOMPSON: Yeah.
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156 1 CHAIR BLEY: I sort of want to apologize 2 because I kind of got this thing --- I was hoping 3 there would be a way to get a clearer definition in 4 the guidance.
5 But I think if you sat down with one of 6 these people and looked at a site and looked at these 7 maps, it wouldn't be a great mystery how far out 8 beyond 200 miles you might have to go.
9 DR. CORRADINI: Okay. All right.
10 CHAIR BLEY: And if you look at -- yeah, 11 we don't know if it's a millimeter or a foot, but we 12 know that volcanoes like the Cascades have thrown ash 13 more -- well over 200 miles away and it ended up in 14 several feet, not just a few millimeters.
15 DR. CORRADINI: I know.
16 CHAIR BLEY: But not, you know, 2,000 17 miles away all plopping in one place, you know, unless 18 something really bizarre happens.
19 MS. THOMPSON: Something that the staff 20 discussed initially very early on in the process is 21 what could reasonably be excluded.
22 And so, what is reasonable to exclude as 23 a hazard and what is reasonable to include, which is 24 why we start with considering the region, the time 25 period of interest and the tectono-magmatic model.
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157 1 And that example that I gave you, 2 everything in that figure is less than half a million 3 years old, but there are only two features in that 4 figure that should be considered because they're the 5 only two that could reasonably result in volcanic 6 hazards at this site or at a proposed site in that 7 area.
8 So, we're looking for -- we were looking 9 to focus on what could be reasonable, what would be 10 credible, not what is in the realm of possibility as 11 anything that may happen.
12 MEMBER KIRCHNER: Because I'm looking over 13 Jose's shoulder here, and he's showing a map with the 14 dispersion from the Iceland volcanoes. But the fact 15 is that although the dispersion is many thousands of 16 kilometers, a reasonable analysis of the situation 17 would suggest that the ash fall problem is not that --
18 it's an airplane issue, but it's not a credible threat 19 to a nuclear --
20 MS. THOMPSON: And there's a difference 21 between dispersion, where the ash could go in the 22 atmosphere, versus where the ash could be deposited on 23 the surface. So that's a consideration as well.
24 (Simultaneous speaking.)
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158 1 to cover all that area.
2 MEMBER KIRCHNER: No. No.
3 MEMBER MARCH-LEUBA: However, can be a 4 thunderstorm right here that deposits a lot while it's 5 raining. If you have a --
6 CHAIR BLEY: If it goes that far, it's 7 much higher than a thunderstorm. I just want to make 8 a comment while you have this picture up here. Back 9 when SSHAC was dreamed up, one of the reasons was --
10 and you can get a simple idea of it from this figure.
11 Suppose each of those models are three different 12 people who's developed them, and they believe in their 13 own model very strongly. And so they don't want to 14 give you much credit.
15 And now you sit down. How do we come up 16 with what's right? And I finally said two things.
17 Get the people together, but we don't just let them 18 say, my model's right. You come forward and you lay 19 out the evidence for why your model might be right, 20 and you seek not your own personal probabilities but 21 what you think is the -- what is a group, you think is 22 the state of knowledge of the community, the technical 23 community.
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159 1 amount. And everybody finally agreed on the joint 2 result that came out of the process. Now, that's the 3 kind of thing they would do here. And maybe somebody 4 really thought they were onto something, especially if 5 that bottom one, say, was separated a lot more. And 6 they really were pushing their model.
7 But when they finally talked about it, 8 yeah, the other ones are much more likely to happen.
9 But under rare conditions, mine could be the right 10 one. So you weight them appropriately, and that's 11 what the process is designed to do, to bring all the 12 evidence together, share it, and come up with a joint 13 view of what's most likely.
14 DR. SCHULTZ: But my question, Dennis, is 15 who are the they that are going to do this, and when 16 is it going to be done? Because the way it's written, 17 it sounds as if the licensee is going to get a SSHAC 18 team together and do the work for their local site.
19 CHAIR BLEY: The truth is very rarely.
20 Most people aren't going to build something right near 21 a volcano, even within a couple hundred miles of a 22 volcano. But it's going to happen rarely, and you do 23 it, and you need to.
24 DR. SCHULTZ: Washington state is 400 25 miles across. So --
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160 1 CHAIR BLEY: Well, and the ash went.
2 MEMBER RICCARDELLA: But it was a SSHAC 3 process that led to the CS report, right? The 4 seismic?
5 CHAIR BLEY: Yeah.
6 MEMBER RICCARDELLA: They came up with the 7 seismic map for the whole central and eastern United 8 States.
9 DR. SCHULTZ: That's what I was talking 10 about before. I think that's an appropriate way of 11 knowing.
12 CHAIR BLEY: There was a basis for looking 13 at all that together. Here, it's a little one, but I 14 think they're going to do it when they have to. I 15 would think their geologists may be able to do the 16 first several steps very quickly to a level they're 17 quite comfortable. Then you get to the step where you 18 say, what of my stuff if it breaks could get me in 19 trouble?
20 And that's not those people. That's 21 somebody else. And that might be released. It just 22 depends on what that hazard is that's likely to get 23 there. So I think we're over-stewing on this.
24 MEMBER DIMITRIJEVIC: Maybe doing this map 25 makes the most sense before the guy --
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161 1 (Simultaneous speaking.)
2 MEMBER RICCARDELLA: I'm sorry. I didn't 3 hear what you said.
4 MEMBER DIMITRIJEVIC: I was saying maybe 5 building his volcano hazard map for United States will 6 make more sense before --
7 MEMBER RICCARDELLA: Suppose I told you 8 one millimeter was the problem. One millimeter of ash 9 deposit is a problem. Could you make a map of the 10 United States with the probability of or frequency of 11 areas that would have one millimeter, maybe a color-12 coded map like that with different frequencies of 13 getting one millimeter?
14 DR. HILL: Yes. The map currently exists.
15 The US Geological Survey is on its second revision of 16 it for ash fall hazards from Cascade volcanoes. So 17 you could easily go out and look at an exceedance 18 probability for one millimeter. I believe they did 19 110 and another thickness and an annual likelihood of 20 occurrence.
21 MEMBER RICCARDELLA: But does that map 22 include Wisconsin?
23 DR. HILL: I can't recall. I don't think 24 so. I'm not aware of recorded deposits for quaternary 25 volcanoes in Wisconsin of any kind. There's always a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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162 1 threshold of initial credibility. Come back to our 2 initial siting criteria of phenomena that have been 3 occurring at the site during the historical period 4 with some uncertainty about the timing and uncertainty 5 of the event, but it still is -- it happened in the 6 past around here.
7 It's not speculating that it might be from 8 the future that the Iceland volcano gave us a trace 9 amount. It's possible, but really, do you see any 10 evidence of this occurring in the past at the site?
11 So we're not really starting an analysis from 12 speculative trace distribution of deposits. These are 13 deposits that have a really credible basis in being 14 there. They're either mapped or, in a broad-brush 15 analysis by the US Geological Survey, have a credible 16 likelihood of occurring.
17 That's the initial step. Then you do the 18 detailed analysis to look at the specific volcano near 19 your site and see, well, rather than an order of 20 magnitude, what are we really dealing with?
21 CHAIR BLEY: You remember when we were 22 doing seismic for various sites, Jerry was here. So 23 they do a lot of digging. They dig up old stuff 24 because he was there. I mean, they don't just guess 25 at it.
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163 1 MS. THOMPSON: Yes. So --
2 MEMBER DIMITRIJEVIC: But maybe 3 uncertainty is equal in both cases because that's not 4 going to represent any realistic frequency of seismic 5 beneath the volcano because we cannot predict the 6 future based on past events.
7 MEMBER RICCARDELLA: Well, that's why 8 you've got a series of tests.
9 MEMBER DIMITRIJEVIC: That's not really 10 the issue, right?
11 MS. THOMPSON: So that highlights another 12 set of challenges in calculating the probability of a 13 hazard reaching the site, which is that the character 14 of volcanic systems can -- or the character of 15 volcanic hazards can change with distance from the 16 source. So ash fall hazards, it's going to differ 17 whether you're on the slope of that mountain or if 18 you're 1,000 kilometers away.
19 There also are different interpretations, 20 or there may be different interpretations on the 21 preserved deposits that are in the geologic record.
22 And then, as I mentioned before, a challenge with PE 23 as well as PH is that the characteristics of volcanic 24 systems can change through time. So we're dealing 25 with non-stationary systems that should be considered, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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164 1 and reaching consensus on that is, like I mentioned, 2 something that can be accomplished using a SSHAC-like 3 process.
4 MEMBER DIMITRIJEVIC: The last eruption 5 was just New Zealand had all these -- whatever you 6 call it, explosion with no ashes.
7 MS. THOMPSON: So yeah. The White Island 8 eruption from last December, just a few months ago, 9 was preceded by a slight increase in earthquake 10 activity at the volcano before the eruption. And then 11 there was that pyroclastic flow off of that, off of 12 the cone, and unfortunately, lives were lost.
13 The following step for once PE and PH have 14 been determined, an applicant would proceed to step 5, 15 which is the Detailed Risk Insights. This uses a 16 similar approach to step 3, which were the Initial 17 Risk Insights. We're again using PRA, and we're 18 assuming that the probability of the SSC, having 19 unacceptable performance or failure, will be equal to 20 PE or PH or both.
21 We would then evaluate the results in the 22 PRA and determine if the resulting hazard is 23 potentially significant to safety, taking no credit 24 for the likelihood or magnitude of the occurrence. So 25 if these insights then show that the hazard is not NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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165 1 significant to safety, an applicant would document 2 their rationale and complete the assessment. If not, 3 they would proceed to step 6.
4 MEMBER DIMITRIJEVIC: This is very 5 mathematically incorrect. So -- and we can help you 6 put that so it makes sense because the fail 7 probability -- fail SSCs always probability. So it 8 cannot be PE. But PE can be considered if you are 9 satisfied with your uncertainty range. So this can be 10 definitely put in that one back there.
11 MS. THOMPSON: Okay. So at the Evaluate 12 Design Bases step, it's important to note this is the 13 only optional step in the Volcanic Hazards Analysis, 14 in the VHA. However, the working group encourages an 15 applicant to perform this step because this is the 16 step that could provide additional performance 17 insights from a focused evaluation of the SSCs' 18 individual design bases that would be considering the 19 unusual demands of the volcanic hazards that would be 20 affecting the site. However, an applicant could 21 decide not to consider their design bases and proceed 22 directly to Mitigation Actions.
23 So an applicant may come to a decision 24 that volcanic ash is still a credible hazard for their 25 site, and rather than reevaluating their design bases, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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166 1 they've determined that they will move straight to 2 Mitigating Actions and implement those. So instead of 3 reevaluating the design bases to determine if the ash 4 fall could be -- if the facility could withstand the 5 ash fall hazard, they may instead proceed directly to 6 Mitigating Actions and determine that they're going to 7 install air filters and implement mitigation 8 procedures.
9 MEMBER RICCARDELLA: This is the Volcanic 10 Qualification Program. Just put a piece of equipment 11 in the chamber and blow it back, and the chamber keeps 12 working.
13 (Off-microphone comments.)
14 CHAIR BLEY: It's not. Thank you. On 15 page 15, you get to the point of saying you've maybe 16 calculated PH, maybe calculated PE, maybe calculated 17 both of them. If either PH or PE shows that potential 18 volcanic hazards did not significantly affect safety 19 -- it's just PH and PE, nothing else -- then 20 additional analysis would not be warranted. I would 21 say and the combination of the two.
22 So if your frequency's very low, you're 23 kind of done. But then, if you're not done and you 24 have either PE or PH calculated, you tell people to do 25 a simplified PRA using the same techniques you used in NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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167 1 step 3. Well, that one assumed that the appropriate 2 SSCs failed, and then you say either the plant's okay 3 or it's not.
4 Here, we've got now a likelihood. There, 5 we assumed the stuff got there. Here, we're saying, 6 no, we don't assume it gets there. There's some 7 likelihood that it gets there. And either we assume 8 it's guaranteed that we blew the thing up and now we 9 have a probability that it got there, or the frequency 10 was such we know that and we assume that it gets 11 there, or we calculated them both and we multiply 12 them, and we have a likelihood that the stuff gets to 13 the site.
14 Now, if we do the same thing as we did in 15 step 3, we aren't taking advantage of having 16 calculated either of those two probabilities. So you 17 have to do something a little more once you get there, 18 or you wouldn't have bothered to calculate PH and PE.
19 You don't use them.
20 MS. THOMPSON: So we do use them. So in 21 the Initial Insights, we're assuming failure equals 22 one, and the Detailed Risk Insights, we're assuming 23 that the failure equals PE or PH.
24 CHAIR BLEY: Or you're doing both. But 25 you're not using them. You've calculated them, but NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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168 1 you say now go do the same simplified theory you did 2 before? No. You need something a little more than 3 that now. Or you just need those frequencies and say 4 that's good enough. It's not going to happen at a 5 rate I care about.
6 (Simultaneous speaking.)
7 CHAIR BLEY: Somehow, I'm not 8 communicating to you. But --
9 MEMBER DIMITRIJEVIC: There's an 10 additional problem which is very important. You 11 cannot do that because you cannot do even the first 12 screening, because you cannot put SSCs to run without 13 knowing what the initiating event is. If you're going 14 to put this to run and use the --
15 (Simultaneous speaking.)
16 CHAIR BLEY: If you've got -- what it 17 means is -- and they didn't really say this. What it 18 means is you have a PRA model, and you know what the 19 SSCs are. And you've looked at the hazard coming 20 here, and you say that hazard can affect these two 21 SSCs.
22 MEMBER DIMITRIJEVIC: Causing what?
23 Transient? Loss of off-site power, that's very 24 different.
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169 1 affect these. Now, I fail those and say, can I do 2 anything to the plan? If it doesn't do an initiating 3 event, nothing happens.
4 MEMBER DIMITRIJEVIC: Well, that's what 5 I'm saying.
6 CHAIR BLEY: So you need that whole PRA 7 model.
8 MEMBER DIMITRIJEVIC: Because I don't want 9 to challenge.
10 (Simultaneous speaking.)
11 CHAIR BLEY: -- a simplified one. But 12 none of that's spelled out. You assume somebody knows 13 how to use these probabilities you've just calculated 14 and how to come up with some meaningful pseudo-PRA 15 calculation without telling them how to do it.
16 MEMBER DIMITRIJEVIC: Well, they might 17 know the problem which we identified before, and 18 that's why much more discussions around the PRA label.
19 And you definitely need the PRA person on your team is 20 -- let's say that we assume that that all is going to 21 cause a loss of off-site power like we did in the 22 seismic.
23 In that case, if my diesel generators are 24 vulnerable, my risk is one because I have to assume 25 the loss of off-site power happened. Until you have NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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170 1 a frequency of occurrence, which is your PE, the thing 2 is I have to assume some type of challenge to the 3 plant operation. If there is nothing to challenge, we 4 can assume the operator will manually trip because 5 volcano exploded --
6 MS. THOMPSON So in step 5, the assumption 7 is that instead of the failure at 1, the failure's at 8 PE, PH, or both. So --
9 MEMBER DIMITRIJEVIC: Initiating event.
10 MS. THOMPSON: So yeah. We are using PE 11 and PH in step 5.
12 CHAIR BLEY: You don't tell people what to 13 do with it.
14 MEMBER DIMITRIJEVIC: Yeah. Yeah. That's 15 true.
16 MEMBER RICCARDELLA: I think in step 5, 17 they assume the probability of failure of the SSC is 18 one, the conditional probability given PE or PH.
19 CHAIR BLEY: That's what they did up 20 above.
21 MEMBER DIMITRIJEVIC: No, PE.
22 MEMBER RICCARDELLA: No, no, no, 23 because up above they didn't have a PE and a PH.
24 CHAIR BLEY: They assume those happened up 25 above.
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171 1 MEMBER RICCARDELLA: Yeah.
2 CHAIR BLEY: In 3, they assume that both 3 happened. In 4, they calculate one or the other, and 4 in 5, they now start looking at the plant and saying, 5 gee, if this is going to affect these vents, do I need 6 to do a calculation on what the risk is, or can I 7 protect the vents somehow from the fallout?
8 So there's an engineering step there that 9 works very nicely, but there's no hint about what to 10 do with those numbers. Why do you calculate them if 11 you don't use them? You're not any better off than 12 you were. You could have gone right from step 3 to 2, 13 to the protective action.
14 MS. THOMPSON: So we're using them as the 15 assumption that if PE -- we're using PE or PH or both 16 to equal failure. That's what we're doing in step 5.
17 CHAIR BLEY: Right. So in the first 18 case --
19 MEMBER RICCARDELLA: Yeah. That means 20 that the conditional probability of failure given that 21 is one.
22 CHAIR BLEY: Yeah. That's exactly right.
23 MEMBER RICCARDELLA: But then if that's 24 low enough, if it's below ten to the minus seventh, 25 you're --
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172 1 CHAIR BLEY: You just made that up. But 2 show me in here.
3 DR. CORRADINI: They don't have a 4 threshold below which residual risk is ignored.
5 CHAIR BLEY: If it's ten to the minus 6 seventh, do they have a criteria? What if it's ten to 7 the minus fifth, and what do you do with it then?
8 What if it's ten to the minus three? What do you do 9 with it then? There's no hint about how to use it.
10 MEMBER RICCARDELLA: I would say if it's 11 greater than ten to the minus seventh, then you go on 12 to step 6. Right? Then you go to the PRA.
13 CHAIR BLEY: You'll have to. If you're 14 going to use that as a criteria --
15 MEMBER KIRCHNER: Dennis has a point. You 16 don't have the do loop that you need. The first time 17 at 3, step 3, you assume it fails as one. Now, all of 18 a sudden, you come up with some measure of the 19 frequency which would reduce that one some percent.
20 You're saying use the PH and the -- what's the other?
21 MS. THOMPSON: The PE.
22 MEMBER KIRCHNER: PE. Then you do it 23 again. But where is the cutoff? How do you know?
24 Why can't you just stop then? Where's the point where 25 you say stop?
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173 1 MS. THOMPSON: Well, through the use of 2 the risk insights, after you've determined your 3 results, you would then determine whether the result 4 is insignificant to safety or if it is significant to 5 safety. We're not providing a cutoff threshold 6 because, again, we're looking at a wide variety of 7 hazards. So what may be an acceptable threshold for 8 one volcanic hazard may not be the same threshold for 9 a different hazard.
10 This is not a one size will fit all for 11 all of the potential volcanic hazards that may occur 12 within the United States at varying locations. But we 13 don't have that threshold cutoff in here for that 14 reason.
15 MEMBER KIRCHNER: Does it go back in any 16 way to the safety goals or the Commission's policy?
17 MS. THOMPSON: We believe this is 18 consistent with the risk-informed performance-based 19 framework. So --
20 MEMBER KIRCHNER: Yeah, but that's jargon.
21 Yeah. The thing is I guess I'm back in Charlie's camp 22 in the sense that if you're a designer, you want to 23 either change the plant design as a result of your PRA 24 informing you, and/or you come to a point in this 25 process where you just say, stop.
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174 1 MEMBER BALLINGER: Applicants are looking 2 for finality --
3 MEMBER KIRCHNER: Yeah.
4 MEMBER BALLINGER: -- period.
5 MEMBER KIRCHNER: There's uncertainty 6 here.
7 MEMBER BALLINGER: Yeah, and employees --
8 there's a 9th Circuit for every plant.
9 MEMBER KIRCHNER: On the seismic side, you 10 can do all this, and then you can show what the 11 probability is, say, of a core disruption or whatever 12 as a failure rate -- as a result of a failure in a SSC 13 or et cetera. Here, I don't see exiting the loop, the 14 do loop.
15 DR. HILL: If I might interject --
16 MEMBER RICCARDELLA: If we'll go back to 17 step 5, if we could, the second bullet says -- you 18 make that assumption on the first bullet, and then the 19 second bullet says you evaluate the results from the 20 PRA. So you got a PRA with initiating event, and you 21 say, okay, now I'm going to assume that certain 22 equipment fails at the probability of PE and PH here, 23 or the frequency of PE and PH. What impact does that 24 have on the PRA? What's the delta risk? And if the 25 delta risk is small, then it's acceptable.
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175 1 DR. CORRADINI: But what's small enough?
2 MEMBER DIMITRIJEVIC: And you can --
3 CHAIR BLEY: I think there's -- the 4 answers come.
5 DR. HILL: I just wanted to bring one or 6 two relevant points. First of all, I appreciate the 7 difficulty in trying to relate this to seismic 8 hazards. There's been decades' worth of engineering 9 analysis, both empirical and modeling, that has gone 10 into understand seismic demands and how structures 11 that are important to safety respond to these 12 different demands.
13 There is a wealth of engineering 14 information for, really, a demand that falls in a very 15 narrow physical window. We're trying to make a 16 technology-neutral approach for a demand, the volcanic 17 hazard, that spans orders of magnitude more variation 18 than the demands coming in from seismic.
19 Yet in the literature, we have almost 20 nothing about the engineering response of SSCs that 21 are important to safety and how they respond to 22 volcanic events. There's even -- the most common one 23 is volcanic ash, and there's an extremely limited 24 amount of information on the impacts of volcanic ash.
25 Most of that's occurred within the last five years.
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176 1 So we're faced with this challenge of --
2 I appreciate the need that it would be so nice if we 3 could come up with a clean number that says, below 4 this likelihood of occurrence, it's not significant to 5 safety. But unfortunately, we lack a technical basis 6 to make that safety kind of decision.
7 So we fall back on the risk insights, 8 which uses not just the sensitivity of the new 9 information in the existing PRA but additional 10 information considering the uncertainties, the 11 confidence in the models, the overall scope of 12 information used to say whether this is significant to 13 safety or not. And as that metric for significance to 14 safety changes, as we're seeing right now, the 15 rationale can be easily marshalled by an applicant to 16 say, based on NRC's current view of what is 17 significant, we believe these numbers for volcanic 18 hazards are or are not significant.
19 DR. CORRADINI: But are you -- let me ask 20 a question of the staff so that at least -- because I 21 think we're all kind of troubled by the same thing.
22 Are you saying you'd let the applicant come and 23 suggest what's a residual risk that's ignorable and 24 not provide them a suggestion as to what that level 25 is?
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177 1 MEMBER DIMITRIJEVIC: Yes. That's good.
2 That's not bad. I'm --
3 DR. CORRADINI: Let him answer. I want 4 them to answer.
5 DR. HILL: Yes. That's correct. So you 6 do not have an established criteria that says, this is 7 what would be the acceptable risk for volcanic hazards 8 for any facility in the United States.
9 DR. CORRADINI: Last time we did that was 10 risk significance in terms of a figure -- I can't 11 remember what those things are called when we had 12 Member Stetkar going crazy. The ESBWR had one level 13 of measure and AP1000 had another level of measure and 14 EPR had another level of measure, and I thought the 15 Committee was going nonlinear about that.
16 It strikes me that you want to have some 17 sort of at least straw-man level of significance below 18 which it's not necessary to look at it. Whether it's 19 PE or PH or the product of PE/PH, it strikes me if I 20 fall below some sort of level as a straw-man starting 21 point, then it's ignorable.
22 And the only one that's out there as a 23 straw man right now -- I'm back to my LMP -- is the 24 Licensing Modernization Program that they basically 25 said, with a series of frequencies, if the frequency NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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178 1 of this with uncertainty falls below some level, I 2 don't consider it.
3 MEMBER DIMITRIJEVIC: This is why I was 4 going to suggest that you remove SECY-98-144 because 5 it doesn't say anything about this inform, and you put 6 the reg guide 1.174, which will tell you about how to 7 consider the risk report.
8 There is something which I heard they will 9 update because there is a difference between relative 10 and -- the regulator didn't make decision about that.
11 We're just discussing ten to minus seven, which we 12 said is not really significant when it comes to the --
13 value minus seven when you're talking about CDF or 14 value minus nine, that will become a most important 15 event. May not be significant from safety goal but it 16 may be significant from the risk insight.
17 So let's reference reg guide 1.174, and 18 then the NRC's going to keep up with their opinions on 19 that subject.
20 DR. CORRADINI: The only reason -- I just 21 want to make sure because I think Vesna's -- makes a 22 much more logical way of saying it than I did. What 23 only troubled me about when you said you leave it up 24 to the licensee is that you could have a multiplicity 25 of values that are all over the map, and we've seen NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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179 1 this happen before with other things that you leave to 2 the licensee. And at least you want to provide them 3 some sort of guidance on how to attack it to begin 4 with. That's what --
5 (Simultaneous speaking.)
6 MEMBER DIMITRIJEVIC: -- will do that for 7 them. Reg guide 1.174 will do that.
8 DR. HILL: One final comment just specific 9 to volcanic hazards. I have to reiterate that the 10 very large uncertainties that we're dealing with here 11 in calculating an eruption probability -- when we talk 12 about thresholds, the term that's commonly used is an 13 expected value of, say, ten to the minus seventh, 14 which implies you have an understanding of the central 15 tendency of the probability.
16 Now, I can make a number up for volcanic 17 hazards, but you really have to come through and do a 18 fair amount of work to have an understanding of 19 whether your expected value probability is going to be 20 at ten to the minus seventh, which -- to get to that 21 expected value means you're considering events that 22 are going to be down ten to the minus eighth and 23 potentially even ten to the minus ninth per year to 24 have an effective understanding of the mean value of 25 probability.
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180 1 So this is a very significant challenge to 2 use -- you can present a criterion of, let's say, the 3 ten to the minus seventh threshold. But in this 4 particular instance, the epistemic and aleatory 5 uncertainties that have to be evaluated are going to 6 be a very significant technical challenge to defend to 7 say, I'm at a threshold; therefore, I do not need to 8 go forward and multiply.
9 DR. SCHULTZ: That's why the definition 10 and the mechanism by which that uncertainty is going 11 to be treated needs to be well defined as part of the 12 process. And it can't be something that is going to 13 be established by licensees A, B, C, D. It has to be 14 well established as to how that's going to be treated.
15 Otherwise, we'll never get to agreement.
16 MEMBER KIRCHNER: Just not the licensee in 17 terms of regulatory certainty. With all due respect 18 to how uncertain this particular challenging problem 19 is, you open the door for intervention that you may 20 have a hard time closing.
21 DR. SCHULTZ: That's right, intervention 22 or just technical agreement.
23 CHAIR BLEY: This is akin to the SSHAC 24 process being used to come up with a seismic hazard 25 curve for an area that's not central and eastern US.
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181 1 I mean, they used it for that whole area, but -- and, 2 of course, it's not a plain estimate. The SSHAC thing 3 is designed to look at --
4 MEMBER KIRCHNER: A whole series of 5 hazards there, not just one.
6 CHAIR BLEY: -- the things that could 7 drive it in different directions. So it's a 8 probability of frequency, which has a mean value as an 9 expected value. And the best you can probably do is 10 some sort of expert group looking at the kind of 11 pictures you have and then trying to assemble them 12 into an uncertainty distribution, come up with a mean.
13 MEMBER KIRCHNER: And is it better, in 14 your mind, Vesna -- because you deal in this space.
15 I don't normally deal in this space. Is it better 16 since there's -- as was very eloquently said, this 17 probability of eruption number is going to be 18 difficult to achieve or you have to appreciate it's 19 going to have large uncertainty. Can you do a better 20 job on probability of ash deposition and mapping 21 versus where do you put the --
22 CHAIR BLEY: The experts in this area say 23 yes. That's what they say. And if that's the long-24 range hazard, it seems to me that's where I would put 25 my efforts.
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182 1 MEMBER KIRCHNER: Yeah. That's where it's 2 going.
3 MEMBER DIMITRIJEVIC: Yes, but the ash 4 distribution is given eruption. So, therefore, that's 5 going to be not able to be -- this is not going to be 6 a small number. It's not going to be ten to minus 7 five. It's given eruption. So that's not going to 8 stream.
9 MS. THOMPSON: It's also important to know 10 that not every ash eruption is going to be the same 11 volume. So what may be modeled may be the maximum 12 credible extent of an ash fall hazard as opposed to 13 what actually occurs in the future in an eruption.
14 So, again, we're dealing with something that is very 15 nonstationary. It's a very dynamic system, and what 16 we model may not be what occurs.
17 So even if we reach that consensus, 18 there's still a fair amount of uncertainty just 19 because of the nature and the changing nature of these 20 volcanic systems.
21 MEMBER KIRCHNER: Let me press a little 22 further, then. I'm showing my deterministic side 23 today, determined to get an answer as an engineer so 24 I can design my plant. But seriously, if there are 25 such good USGS maps for the Cascadian system, how NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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183 1 would -- walk us through how we ought to use those 2 maps in this process.
3 MS. THOMPSON: Within this process?
4 MEMBER KIRCHNER: Yeah, within your 5 process.
6 MS. THOMPSON: Okay. So if we assume that 7 we have evidence of a quaternary volcano, it's within 8 our region of interest and it is within the time 9 period if interest, and it is consistent with our 10 tectonic magnetic model, and we look at the 11 distribution of ash fall, most of the -- the use of 12 that hazard map would be used at the Screen Volcanic 13 Hazard step. That's where we would first use it.
14 We would consider those maps with respect 15 to our site. Could the modeled ash fall from that map 16 reach our site? If we're considering a site in New 17 Jersey, the answer is probably no. If we're 18 considering a site in Montana, we'd have to look at 19 that.
20 So that's where we're at, the 21 deterministic screening, looking at what could 22 credibly reach the site. If we determine yes, it is 23 a credible -- it's credible that an ash fall deposit 24 would be reaching our site, we would move on to step 25 3, consider our Initial Risk Insights assuming that if NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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184 1 the ash fall arrives at the site, we have failure of 2 an SSC.
3 We continue on. If that result is that 4 the failure of that SSC from the arrival of ash fall 5 at the site would be significant to safety, then we 6 would move on, calculate the PE and PH for the source 7 volcano of this ash fall, which would be step 4, and 8 then we would get into step 5, where our -- most 9 likely PH. The probability of the hazard reaching the 10 site would be considered in our Detailed Risk 11 Insights, where we would assume that failure will 12 occur at PH in our system.
13 MEMBER KIRCHNER: Let me pursue this.
14 MS. THOMPSON: And then do you want me --
15 MEMBER KIRCHNER: I'm sorry, Dennis. If 16 I can go one more step. Okay, because I want to go 17 back to where Vesna might have been starting.
18 So okay. Most of the plants are in the 19 eastern US, east of the Mississippi. So if we were to 20 just take this reg guide right now and -- let me just 21 throw this out arbitrarily. Anything east of the 22 Mississippi, how quickly would we screen out the 23 volcanic hazard?
24 MS. THOMPSON: Most likely in step 1 or 2.
25 I would say the --
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185 1 MEMBER KIRCHNER: And how much effort 2 would that take?
3 MS. THOMPSON: -- surface hazards would 4 screen out in step 1. So lava flows, pyroclastic 5 flows, those would all screen out at step 1. Ash 6 fall, we would consider the hazard map and look at our 7 deterministic screening and look at the geologic 8 record to see if there are ash deposits within the 9 quaternary period at that specific site.
10 And I would say, most likely, you would 11 screen out as well, and then you would be done. And 12 if it took a -- I'm trying to imagine how much time.
13 If you are familiar with the area that you are working 14 in --
15 MEMBER KIRCHNER: You were part of the 16 Clinch River ESP.
17 MS. THOMPSON: Yes.
18 MEMBER KIRCHNER: So give us a feeling.
19 How quickly would we get through this for Clinch 20 River?
21 MS. THOMPSON: It would probably take me 22 more time to write the report than reach a conclusion.
23 MEMBER KIRCHNER: All right.
24 MS. THOMPSON: I don't mean to be funny, 25 but that's --
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186 1 MEMBER KIRCHNER: No, I know. I'm just --
2 MS. THOMPSON: It would take me more time 3 to document the results than to reach a conclusion.
4 MEMBER KIRCHNER: That's good to know.
5 MS. THOMPSON: Yeah. This is not a 6 burdensome thing if you are well removed from volcanic 7 hazards.
8 MEMBER KIRCHNER: That gives me a little 9 more certainty.
10 DR. CORRADINI: But I think we're --
11 MEMBER DIMITRIJEVIC: Okay, but let's look 12 from the design perspective.
13 MS. THOMPSON: So that's actually what 14 we're stepping into next, which is step 6, to evaluate 15 the design bases once we have determined PE and PH and 16 moved in after our Detailed Risk Insights and we're at 17 the optional step of considering the design bases 18 where we are looking to develop a more accurate limit 19 state for the SSCs that would be affected by the 20 potential volcanic hazard reaching the site.
21 So, specifically, we're looking at 22 exceedance likelihoods given the demands of the 23 volcanic hazard that reaches the site. And if you 24 remember the range of different demands that may be 25 impacted on the site based on what the hazard is, the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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187 1 demands of a lava flow are very different from the 2 demands of an ash fall hazard.
3 We would also at this step consider the 4 actual material properties that would be affected and 5 looking at facility-specific information related to 6 the SSCs that would be affected by the hazard. So 7 this is the stage where we're looking at what can the 8 actual facility withstand, and can it withstand the 9 particular demand of that specific volcanic hazard?
10 And this is a place where the conclusion 11 reached for ash fall may be different than the 12 conclusion reached for a lava flow, so again 13 considering the dynamic nature of volcanic hazards and 14 their varying demands. So once that is done, we would 15 look at reevaluating risk insights based on this new 16 facility-specific information, and then this may allow 17 us to enhance the design bases if an applicant chooses 18 to go that route.
19 MEMBER DIMITRIJEVIC: This is -- sorry.
20 I was trying to say something before for this design 21 similar to her hazard. So let's say that we want to 22 build NuScale next to Columbia. I would say go ahead.
23 There is nothing which can -- I mean because the only 24 important things are ECCS components and the passing 25 cooling. There is absolutely nothing I can think from NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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188 1 volcano.
2 So that would be example of a design 3 that's not really vulnerable to this type of hazard.
4 MS. THOMPSON: And that's exactly what 5 would happen at this step where an applicant would 6 consider the specific systems and the effect of the 7 volcanic hazards on those specific systems. And if 8 they do reach a conclusion that given the design of 9 the facility, the volcanic hazard would not affect the 10 site, they can at this point screen out or complete 11 the analysis because no further analysis is needed.
12 The volcanic hazard, although reaching the site, will 13 not affect the facility, given the site-specific and 14 facility-specific parameters. And they would be done 15 with their analysis, and they would be complete.
16 DR. CORRADINI: Okay. So let's play this 17 one out. I think what you guys have done is very 18 good. I just am looking for examples so that if I'm 19 an applicant, I would see an example for step 1, an 20 example for step 2. So let's take an example here.
21 I've got all these supposed advanced reactors with 22 supposed passive decay heat removal systems that 23 either have air heat exchangers or water heat 24 exchangers that ash deposits will follow them.
25 So do I assume one millimeter thousand?
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189 1 Do I do a parametric on that? At what point do I say 2 that that's an unacceptably large amount of following 3 factor on these passive heat exchanger systems?
4 Strikes me I'm going to have to make a judgment. So 5 that judgment would be probably based on frequency, 6 which is the chance of this happening compared to all 7 the other things I'm worrying about on getting rid of 8 my passive decay removal system is zero.
9 CHAIR BLEY: Yeah, but if you can't do it 10 on frequency, then you get some guy like you to 11 evaluate how your heat exchangers will do in this 12 environment.
13 MS. THOMPSON: And that decision to 14 determine what the effect would be, what the volume of 15 ash could be given the passive systems, that is 16 another question that could be posed. And you could 17 use a SSHAC process to consider, what volume of ash 18 could we reasonably expect to reach the site? And 19 should we consider that to be our failure state, or is 20 this amount of ash that we've come to a consensus on 21 -- let's say it's two millimeters.
22 Well, the engineers have decided that two 23 millimeters is something that this facility can 24 withstand, and that would be done at this stage, 25 evaluating your design bases. So if you can make the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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190 1 justification and document the rationale for that 2 conclusion, you could end the volcanic hazards 3 analysis and be done.
4 DR. CORRADINI: I see where you're going.
5 I'll point to the empty chair. Now I'm starting to 6 become like Charlie that I am imposing requirements on 7 this technology that I'm not imposing on any other 8 technology to a level that the uncertainty -- if I 9 started thinking about other ways to make electricity 10 and I say, well, I'm worried about a volcanic eruption 11 on all these solar arrays and all these wind 12 turbines --
13 CHAIR BLEY: Wait, wait. No, no. Come 14 on. You don't -- so you lose production. That's 15 different than having a nuclear release from a nuclear 16 plant. That's why we've got all the regulation we 17 have.
18 DR. CORRADINI: Okay. But if I go through 19 from a frequency standpoint, if it's a low enough 20 frequency, it's still a residual risk.
21 CHAIR BLEY: Well, that's true.
22 DR. CORRADINI: But that's got nothing to 23 do with a coal plant or a solar plant.
24 MEMBER MARCH-LEUBA: The risk is a product 25 of the frequency testing consequences. I mean, a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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191 1 solar plant is supposed to --
2 (Simultaneous speaking.)
3 CHAIR BLEY: Well, if the consequences of 4 losing electric power are higher than --
5 (Simultaneous speaking.)
6 DR. CORRADINI: I'd probably kill more 7 people losing electric power and have a loss of 8 refrigeration than all the stuff I'm worried about 9 here.
10 MEMBER PETTI: If there's nothing else 11 you've learned from this almost three-and-a-half-hour 12 exercise is that some examples that are really 13 different, right, I think would help clarify all 14 these.
15 MEMBER DIMITRIJEVIC: You mean the 16 examples only on the --
17 MEMBER PETTI: Of using the process.
18 MS. THOMPSON: Of using the process.
19 Okay.
20 MEMBER MARCH-LEUBA: By the way, I sent 21 you a link to the US Geological Survey of 160 US 22 volcanoes and the risk.
23 MEMBER DIMITRIJEVIC: They can only do 24 hazard analysis. They're not going to take some PRA 25 to run data.
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192 1 MS. THOMPSON: I'll take that note back to 2 the working group. Yeah.
3 MEMBER REMPE: Some of the examples with 4 the non-ash cases are perhaps less dependent on the 5 design. It's just the site. And so, then, in some of 6 the examples, you're going to have to say, this will 7 depend on the design details, and just cut it off.
8 Right?
9 MS. THOMPSON: Mm-hmm.
10 MEMBER REMPE: With all the work you've 11 done, we're -- I mean, this was started out because of 12 what's going on in Idaho. Can you even rule out the 13 surface ones, but you can't do the ash ones at this 14 time or at least give some insights for that site? I 15 mean, you've heard Steve and a bunch of people saying, 16 when does this get done? Have you gone far enough?
17 And you talked about on the East Coast, 18 you can just rule them out. Have you done enough that 19 you can say certain things are not ruled out?
20 MS. THOMPSON: It would depend on site.
21 Again, it's very site-specific. There are some 22 hazards that you can rule out almost immediately based 23 on geologic setting alone and the characterization of 24 the volcanic system. Whether we could as a staff put 25 together an appendix saying, if you're located here or NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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193 1 there, you don't have to consider this, may take some 2 additional time as we move our way west. But --
3 DR. SCHULTZ: I think it could be well 4 worth it.
5 MS. THOMPSON: Okay.
6 CHAIR BLEY: The other side of that is, 7 how many people are going to come up with a siting 8 requirement that's going to put them in need of 9 considering this? In 60 years, we've had 2 plants.
10 MEMBER REMPE: The other thing I guess I 11 was thinking about is, often, you refer to the PRA.
12 Some of these things are going to be so simple they're 13 just going to have a maximum -- or a hazard 14 assessment. Right? They're not going to have much of 15 a simplified -- yeah. And so those kind of questions, 16 I think are -- we need to broaden it a bit.
17 MS. THOMPSON: Okay. That's something 18 we'll take back, too. So if after evaluating the 19 design bases there is still a credible hazard, an 20 applicant can choose one of two actions. They can go 21 back and reevaluate again, or they can proceed to 22 Mitigating Actions. And this is kind of an iterative.
23 As we get towards the end, you can evaluate your 24 design bases, evaluate mitigation actions, and let's 25 say your mitigation actions still do not resolve the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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194 1 risk posed by the volcanic hazard.
2 You could then go back to step 6 several 3 times if you wanted to, to perform even more detailed 4 analyses to get additional information based on your 5 specific site and your specific design. So moving on 6 to Mitigation Actions doesn't necessarily mean that 7 you're committed to those actions. This is just an 8 iterative process that an applicant can take.
9 So, as I mentioned before, most volcanic 10 eruptions are preceded by precursory earthquakes or 11 other activity. This warning time can occur over 12 several hours. More commonly, you get several weeks 13 of elevated activity. And Mitigation Actions may be 14 practicable in the warning time that you have between 15 when there is a change to the volcanic system and when 16 the hazard arrives at the site.
17 An example of this is, again, the Columbia 18 Nuclear Generating Station. As I mentioned before, 19 it's the only current operating reactor that has 20 design bases volcanic hazard for ash fall. It's 21 located more than 200 kilometers away from the source 22 of that ash fall in the Cascades. So the Columbia 23 site has several hours to prepare for an ash fall 24 event.
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195 1 maintenance procedures, and air filtration is 2 installed in that warning time, which the staff at the 3 time of licensing reviewed and determined that was 4 sufficient time to implement all of these mitigation 5 actions. It's also worth noting that volcanic ash 6 fall is a commonly mitigated hazard around the world.
7 So, as I mentioned before, we have more data for ash 8 fall than we have for any of the other volcanic 9 hazards with respect to mitigation and evaluation.
10 So --
11 MEMBER MARCH-LEUBA: Would you say that 12 the other hazards are deadly? If you get caught in 13 the lava flow, forget it.
14 MS. THOMPSON: So that's the -- the next 15 thing I'm getting to is that, as you mentioned, some 16 surface flows, their properties are much different.
17 They are much more deadly, and -- but some of them 18 have been successfully mitigated worldwide. Other 19 attempts have not been successful.
20 The photo here shows one such attempt.
21 This is from the 1960 eruption on Kilauea. You can 22 see a little bulldozer in the center. That bulldozer 23 is constructing a five-meter-tall diversion for the 24 lava flow.
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196 1 exists.
2 MS. THOMPSON: Exactly. This barrier was 3 successful in diverting the lava flow for several 4 weeks, but it was ultimately overtopped. But if 5 you're considering several weeks of successful 6 mitigation of a flow hazard, if you're looking at 7 evacuation times for people or other factors, several 8 weeks can be very important for some of these 9 locations. So --
10 MEMBER BALLINGER: My directive is don't 11 build a power nuclear plant on Hawaii.
12 MS. THOMPSON: I would say consider the 13 tectono-magnetic model when siting on the Hawaiian 14 Islands.
15 MEMBER BALLINGER: I'm looking at the 16 tectono-magnetic model right here.
17 MS. THOMPSON: So if mitigation actions 18 are proposed, there should be appropriate monitoring 19 in place so that there is forewarning or early warning 20 of an eruption. Any mitigation action should also 21 include clear criteria for when to start those actions 22 based on a change in the monitoring, and there should 23 be a basis to demonstrate that the mitigating actions 24 are practicable in the warning time between 25 notification of a potential event and the arrival of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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197 1 the hazard at the site.
2 CHAIR BLEY: Somebody at this table 3 brought up something that's happened with floods and 4 that when to protect the nuclear facility, they wanted 5 to drain water through a dam, people downstream of the 6 dam objected that they didn't want to be inundated.
7 And if you're going to have a plan for diverting the 8 stuff if you decide to live close enough to need it, 9 you might have other political problems that keep you 10 from carrying out your plan.
11 MS. THOMPSON: That's an excellent point.
12 CHAIR BLEY: Does NRC look at that? You 13 hadn't before the flood stuff came up.
14 MS. THOMPSON: I will take that back and 15 check on that for you.
16 CHAIR BLEY: Okay.
17 MS. THOMPSON: So the last step in 18 evaluating the mitigation actions is to reevaluate the 19 risk insights taking credit for the mitigation action.
20 So if after all of the steps have been 21 completed, a hazard is still not able to be mitigated 22 through design or operations, an applicant has two 23 choices. They can go back into the process and 24 continue to iterate, getting more and more detailed 25 analyses, or they can proceed to Siting NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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198 1 Considerations, where an alternative site may need to 2 be considered.
3 As we mentioned before, volcanic hazards 4 are spatially restricted. So one site may be 5 unsuitable while another site located several 6 kilometers away would have less risk significance or 7 a more acceptable risk.
8 So now that we have been through the 9 staff's approach, I promised you I would address IAEA 10 SSG-21, the Volcanic Hazards Guide, and how we have 11 harmonized with that. And we are there.
12 Specific Safety Guide 21 is for volcanic 13 hazards in site evaluation at nuclear installations.
14 This IAEA guide considered a range of facilities, from 15 fuel installations all the way up to light-water 16 reactors. The NRC's draft guide is consistent with the 17 IAEA approach, which includes an initial screening for 18 volcanoes, although the IAEA guide uses 10 million 19 years instead of the quaternary period of 2.6, which 20 is consistent with the NRC's geologic site 21 characterization.
22 The IAEA approach also uses the tectono-23 magnetic model, and it stops at a detailed evaluation 24 of hazards at the site. And again, because it's 25 covering a range of installations, the hazard approach NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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199 1 is scaled to those installations.
2 The NRC staff's VHA approach integrates 3 risk insights throughout the analysis, which is 4 consistent with the graded approach that the IAEA 5 guide uses, and it's also providing a practical and 6 transparent basis to determine if volcanic hazards are 7 significant to risk within the NRC's framework.
8 As I mentioned before, there are three key 9 differences with the IAEA safety guide, which is why 10 the staff did not choose alternative 3 in the 11 regulatory analysis, which was to adopt this guide.
12 The first is that the IAEA safety guide outlines 13 specific site exclusion criteria for some volcanic 14 hazards. So if the hazard were to occur at the site, 15 the site is deemed not suitable for use.
16 However, the NRC staff determined that 17 that is not consistent with our risk-informed, 18 performance-based framework, and we allow the 19 possibility for design basis or mitigation actions to 20 address the hazard.
21 DR. CORRADINI: Just so I understand, this 22 means after they look at step 1, if they didn't pass 23 step 1, they were out?
24 MS. THOMPSON: Yes.
25 DR. CORRADINI: Okay.
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200 1 MS. THOMPSON: So this would be -- an 2 example of this, one of the exclusion criteria for a 3 site is a debris flow. So if a debris flow would 4 occur at a site under the IAEA guidance, that site 5 would be not suitable. It does not consider whether 6 the depth of the debris flow that reaches the site is 7 one inch or ten feet. It doesn't give consideration 8 for the hazard significance. So --
9 MEMBER BROWN: Let me springboard off of 10 Mike's comment. The site exclusion criteria 11 inconsistent with risk performance, does that mean the 12 IAEA approach is more prescriptive or more restricted 13 than what you're proposing in the --
14 MS. THOMPSON: Yes.
15 MEMBER BROWN: That's what it sounds like:
16 MS. THOMPSON: Yes. It's more 17 restrictive. So if a lava flow could occur at the 18 site, the site is excluded.
19 MEMBER BROWN: Within what? A ten-20 million-year period?
21 MS. THOMPSON: I don't recall the period 22 of time. It's just, if it occurs, the site is out.
23 MEMBER BROWN: If it could, but for 24 whatever --
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201 1 magnitude. So a pyroclastic --
2 MEMBER BROWN: Or time.
3 MS. THOMPSON: Yes. If it occurs, the 4 site is unsuitable.
5 MEMBER BROWN: You mean occurs or occurred 6 in the past?
7 MS. THOMPSON: Occurs. If it could reach 8 the site, if that hazard could occur at the site, the 9 site is unsuitable.
10 DR. HILL: If I could clarify, the IAEA 11 couches it in terms of a capable volcano, which has a 12 credible -- it could be a new volcano in the future or 13 an existing volcano. So if a capable volcano has the 14 potential to erupt a hazardous phenomena that reaches 15 the site, and that phenomena is a lava flow, the site 16 is not suitable for development.
17 So the capability has no probabilistic 18 connotation. It's just this is credible in the 19 island.
20 MEMBER BROWN: In other words, sometime, 21 somebody has determined it might have been there, and 22 it might be again, and therefore, we can consider it 23 credible, and therefore it's excluded.
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202 1 where a nuclear power plant is being potentially shut 2 down because of the danger from a pyroclastic flow 3 that may be from a volcano 150 kilometers away, even 4 though the best science would say by the time that 5 pyroclastic flow got to the site, it would be very 6 dilute and you could probably stand up in it if you 7 had a respirator. It'd be low temperature. It'd be 8 like an ash fall more than anything else.
9 But nevertheless, it meets the criteria of 10 -- it's a pyroclastic density current, or pyroclastic 11 flow. Therefore, under IAEA guidelines, any 12 pyroclastic flow at the site means the site cannot be 13 used. So it's very restrictive in viewing it's all or 14 nothing for some phenomena.
15 (Simultaneous speaking.)
16 MEMBER BROWN: -- occurring now, but --
17 MS. THOMPSON: That it could.
18 MEMBER BROWN: -- if it could.
19 DR. HILL: It has a credible potential to 20 occur.
21 MEMBER BROWN: What has happened five 22 million years ago, it could still credibly.
23 MEMBER DIMITRIJEVIC: But does it apply 24 only for new plants?
25 MEMBER BROWN: No. They're talking about NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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203 1 shutting down a plant.
2 MEMBER DIMITRIJEVIC: I know he said that, 3 but the guide, I don't know what she's talking --
4 MS. THOMPSON: It is for any nuclear 5 installation.
6 DR. CORRADINI: Current or future.
7 MEMBER DIMITRIJEVIC: Current or future.
8 DR. HILL: That depends on its use by a 9 member state.
10 (Simultaneous speaking.)
11 MEMBER DIMITRIJEVIC: -- the title of it?
12 MS. THOMPSON: So the title is just any 13 nuclear installation. And the application to new or 14 current facilities is a country-by-country basis.
15 MEMBER MARCH-LEUBA: But the new reg guide 16 from NRC, it applies to new plants?
17 MEMBER DIMITRIJEVIC: Only for new plants.
18 MS. THOMPSON: This draft guide would only 19 apply to new plants, new applications.
20 CHAIR BLEY: Reactors.
21 MS. THOMPSON: Reactors.
22 CHAIR BLEY: Jenise, I don't recall 23 another reg guide going to the extent you're going 24 here to harmonize with IAEA standards. Is this 25 something new, or do you just feel moved to --
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204 1 MEMBER BROWN: I can -- I think a couple 2 of the reg guides we've done in our area have had 3 harmonization where they have springboarded out of 4 international standards.
5 CHAIR BLEY: And explain in detail why 6 they differ?
7 MEMBER BROWN: Or why they're similar.
8 I'm trying to remember which ones, but we've done 9 several of them over the last few years. And 10 harmonization has been they considered those things in 11 the development of the new reg guide, and they didn't 12 talk about exclusions. They didn't reference -- in 13 fact, it was on the -- which one is it?
14 CHAIR BLEY: You don't need to --
15 MEMBER BROWN: Okay. There's one coming 16 up that says, hey, they're just incorporating the IAEA 17 or some international standard as the reference.
18 MS. THOMPSON: The harmonization section 19 with international standards is a requirement for new 20 regulatory guides that we're issuing. The reason that 21 we went to so much detail is because there is an 22 existing standard, and we do take certain exceptions 23 to some of the content, and we wanted to spell that 24 out clearly.
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205 1 start with.
2 MS. THOMPSON: Yes. Yeah. So we didn't 3 have a reg guide to update. So the new requirement 4 for reg guides includes this section, and we went to 5 the level of detail that we did to call out the 6 specific differences.
7 The second difference is that IAEA accepts 8 deterministic analyses for the detailed VHA, but for 9 the approach that we've outlined in the draft guide, 10 we only use deterministic for a screening and then use 11 probabilistic risk insights for the more detailed 12 analysis.
13 And, finally, the IAEA safety guide 14 requires licensees to conduct monitoring of the 15 sources of the potential volcanic hazards at their 16 sites. But the NRC concludes that the function of 17 monitoring and issuing eruption warnings is the 18 purview of the US Geological Survey as part of their 19 statutory role here in the US.
20 CHAIR BLEY: And you have some kind of 21 joint agreements or meetings with them, right?
22 MS. THOMPSON: We -- yes.
23 CHAIR BLEY: I mean, in a lot of areas --
24 MS. THOMPSON: Yes.
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206 1 agencies.
2 MS. THOMPSON: Yes, and the key takeaway 3 here is that an NRC licensee with a volcanic hazard 4 would not need to implement their own independent 5 volcano-monitoring program, which is what would be 6 prescribed if they were following the SSG-21 issued by 7 IAEA. So that is the key difference there.
8 Now that we've discussed the 9 harmonization, home stretch. Future plans. We will 10 be issuing the draft guide for public comment and 11 interim use later this spring. The reason for this is 12 so that we can solicit both stakeholder feedback and 13 public comment but also get some feedback from 14 prospective applicants that are using the draft guide, 15 so getting some hands on the ground. This is what 16 worked. This is where things weren't clear. Getting 17 some very critical feedback of the process outlined in 18 the draft guide.
19 We also have a staff member who's involved 20 in the working group for ANS 2.34, which is a 21 consensus standard under development for volcanic 22 hazards. And we also --
23 MEMBER REMPE: I haven't heard of that 24 one. Is that actually in process now?
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207 1 information we have from our member on the working 2 group is that we anticipate a draft guide -- or not a 3 draft guide. Sorry. We anticipate the final 4 standards sometime in 2022, at which time the staff 5 will review.
6 CHAIR BLEY: Will this be one of the PRA 7 standards, or is it a completely separate standard?
8 MS. THOMPSON: It's a separate standard.
9 MEMBER REMPE: Is it applicable to all 10 plants or new facilities?
11 MS. THOMPSON: I am not the working group 12 representative, so I'm not sure where the current 13 scope is with the standard. So I can make a note and 14 get back to you.
15 MEMBER REMPE: Thank you.
16 MEMBER BROWN: What is ANS 2.34? I missed 17 that.
18 MS. THOMPSON: It is a consensus standard 19 under development for assessing volcanic hazards.
20 MEMBER BROWN: Oh.
21 DR. CORRADINI: I was just going to say if 22 Budnitz is not on it, let's nominate him.
23 MEMBER BROWN: I guess my question would 24 be, if ANS is going to issue a standard and you get 25 this reg guide out, are you then going to be faced NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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208 1 with revising your standard for consistency or 2 whatever with the ANS standard? Why are you that far 3 in advance?
4 MS. THOMPSON: I'm actually going to get 5 to that. So part of the reason that we are this far 6 in advance is because we anticipated a prospective 7 applicant developing an application, and we wanted to 8 have some kind of draft guidance available for that 9 applicant to use in the development of an application 10 using what the NRC considers to be an acceptable 11 approach for assessing volcanic hazards. And I'll get 12 to some of that in the time line.
13 MEMBER BROWN: You answered my question.
14 MS. THOMPSON: Okay.
15 MEMBER BROWN: Thank you.
16 MS. THOMPSON: The staff also opened a 17 comment capture email so that regardless of where we 18 are in the reg guide development process, members of 19 the public can provide us their feedback. This is 20 especially true for stakeholders who may be 21 implementing the draft guide as they develop their 22 applications. And the staff will address any of the 23 comments received through this comment capture email 24 as though they were received as part of the formal 25 public comment period. And to date, we have already NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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209 1 received two comments through our comment capture 2 email.
3 The comment capture email, we opened that 4 when we issued the draft outline to the public in 5 early October of last year in -- we did a public 6 meeting in October with the outline of the draft 7 guide, seeking initial comments and feedback from 8 interested stakeholders. And we've left the comment 9 capture box open, and we will continue to keep the 10 comment capture box open as long as the draft guide is 11 still in draft form.
12 DR. SCHULTZ: Is there a time schedule for 13 that?
14 (Off-microphone comments.)
15 DR. SCHULTZ: No, but -- okay. I saw 16 that. I thought we might have a month somewhere in --
17 MS. THOMPSON: So some of these do have 18 months. So next month, we will be presenting a 19 digital exhibit at the Regulatory Information 20 Conference. The purpose of that exhibit is to 21 announce the hopefully imminent release in the Federal 22 Register of the draft guide, and --
23 CHAIR BLEY: Digital exhibit's new to me.
24 Is this like a poster session but on a computer 25 screen?
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210 1 MS. THOMPSON: Yes. The working group 2 took inspiration from a movie trailer. So ours has 3 videos and animations in it. So if you're at the RIC, 4 please stop by and see us. It'll be worth the two and 5 a half minutes of your time.
6 MEMBER KIRCHNER: Are the animations going 7 to scare the general public? You're going to put 8 illustrations of volcanoes erupting and nuclear plants 9 together?
10 MS. THOMPSON: We did not put nuclear 11 plants in the animations, but there are animated 12 examples of volcanic hazards.
13 CHAIR BLEY: Make sure you have the one 14 where people are touring the Icelandic magma flows 15 that are going into the water, and you can watch the 16 boat bounce around as the things go in the water.
17 MR. WIDMAYER: ACRS and two and a half 18 minutes don't go together in a sentence.
19 MS. THOMPSON: I'm just going to continue 20 on. Later this spring, we anticipate the issuance of 21 the draft guide for public comments, and we anticipate 22 receiving public comments throughout the remainder of 23 this year. Next year, in 2021, we look to address 24 these public comments, and we will at that time, we 25 hope, be receiving some initial feedback from NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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211 1 prospective applicants that are using the draft guide 2 to develop an application.
3 And then, based on the public comments 4 that we receive and any feedback from prospective 5 applicants implementing the guidance, we may decide to 6 revise the draft guide based on what we receive.
7 Looking ahead to 2022, and to ensure that 8 we remain consistent with the content of the ANS 9 standard currently under development, we anticipate 10 that that standard will be issued in 2022, at which 11 time the staff will review and then finalize and issue 12 the regulatory guide.
13 Last slide.
14 DR. SCHULTZ: Jenise, does that mean that 15 you're planning on considering the ANS input?
16 MS. THOMPSON: That is the working group's 17 current intention. Yes.
18 DR. SCHULTZ: Okay. Thank you.
19 MS. THOMPSON: So finally, at the start of 20 the presentation, I outlined several goals that the 21 working group set for the draft guide. Our 22 conclusions are that we've met these goals and we've 23 developed a draft guide on volcanic hazards that's 24 consistent with the risk-informed, performance-based 25 framework that we have here at the NRC.
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212 1 The draft guide provides opportunities for 2 an applicant to evaluate the risk significance of 3 potential volcanic hazards and end the analysis if the 4 hazards are not significant. So, again, we were 5 considering the burden on an applicant as one of our 6 goals, and we believe we've met that.
7 And, finally, the working group recognizes 8 that although only a few sites in the US might need to 9 evaluate volcanic hazards, the draft guide provides a 10 practicable, open, and traceable approach that is 11 appropriately protective of public health, safety, and 12 the environment.
13 That is all.
14 CHAIR BLEY: Thank you very much, Jenise.
15 Are there any more questions from the 16 Committee?
17 Derek, would you get the phone line open 18 for us? We had a plan. I don't know if we still have 19 it, and we don't get a hint. Just double-check, 20 please.
21 Is there anybody in the room who would 22 like to make a comment? If so, please come to a 23 microphone. Nobody?
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213 1 your name and what your comment is.
2 Derek? It's open?
3 It sounds like nobody's there. We'll go 4 around the table. But first, the staff has not asked 5 us for a letter at this time. I'd be interested in 6 any summary comments the members have and if any of 7 you think we ought to write a letter at this time or 8 wait until the public comment period is over, or maybe 9 write one during that time period.
10 I'm going to start with Vesna.
11 MEMBER DIMITRIJEVIC: You mean of a letter 12 or general comment?
13 CHAIR BLEY: General comments, and do you 14 think we ought to write a letter now or later or ever?
15 MEMBER DIMITRIJEVIC: I think we can 16 provide -- this is obviously written -- it's not 17 written by a nuclear PRA person, parts of it. So it 18 has some terminology which is not applicable to the 19 risk-informed nuclear things, and therefore, we can 20 propose some editing changes which will change that.
21 So from the point of the editing changes, 22 I don't know, how is it done in general? I mean, I 23 know that you said the data instead can use to provide 24 their own notes. I will be willing to provide those, 25 my motes, after we finish the PRA section or NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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214 1 something. I mean --
2 CHAIR BLEY: We don't know yet if that's 3 appropriate --
4 MEMBER DIMITRIJEVIC: I think that is 5 appropriate. That would be my editorial notes. On 6 the high level, now I think -- I cannot really decide, 7 should we write the letter now or after? Maybe we can 8 give it some general direction if we can --
9 CHAIR BLEY: We can't do that.
10 MEMBER DIMITRIJEVIC: No? So --
11 CHAIR BLEY: As a committee, we either 12 write a letter or we don't.
13 MEMBER DIMITRIJEVIC: No, no, no. I know.
14 But meaning the letter, do you think we can write a 15 letter which will be useful for them?
16 CHAIR BLEY: I think we could write a 17 letter that we would think would be useful for this.
18 Any more?
19 MEMBER DIMITRIJEVIC: Well, the only other 20 things which I want to say which I learned through my 21 very old practice here is one of my -- one other 22 person I cooperate on my very complex application. If 23 things are more complex, more simple should we keep.
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215 1 how this will work, we can concentrate on the things 2 we know so we have a really good frame without making 3 it too complex.
4 So I will in general simplify and 5 concentrate on the things which we know. And you use 6 uncertainty so many times in this thing, so it's 7 taking in account uncertainty, taking account 8 uncertainty, taking account -- but that doesn't mean 9 too much, I mean other than if we don't say use 95 10 percent or something. But we take account uncertainty 11 how? We just acknowledge its presence. I mean, so I 12 think maybe we should actually write the letter.
13 CHAIR BLEY: Thank you.
14 Charlie?
15 MEMBER BROWN: Number one, I wouldn't 16 write a letter right now. It's very much in fluid.
17 That was a good meeting, a lot of good information.
18 But based on doing several of these myself, I've found 19 it useful to get the public comments, particularly 20 since the ANS standard is being developed as well as 21 the -- incorporate the public comments and see how 22 this thing moves.
23 The transcript is always available to this 24 team to see if they think -- if they deem any of our 25 suggestions and observations during the meeting are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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216 1 useful. But I would not write a letter right now.
2 It's just too fluid.
3 CHAIR BLEY: Thank you.
4 Pete?
5 MEMBER RICCARDELLA: That was a very, very 6 interesting presentation. I liked the analogy with 7 the seismic risk evaluation. And I'm kind of 8 uncertain as to whether to write the -- I think we 9 should eventually write a letter on this, but whether 10 we do it now or after the public comment, I'm not --
11 I don't have a strong opinion.
12 CHAIR BLEY: Thank you.
13 Jose?
14 MEMBER MARCH-LEUBA: Yeah. I don't have 15 a truly informed opinion, but that hasn't stopped me 16 before. So just pointing out that since the RG is out 17 for public comments, any person interested can 18 provide --
19 CHAIR BLEY: It's not out yet.
20 MEMBER MARCH-LEUBA: Whenever it's out.
21 I thought you provided the email.
22 MS. THOMPSON: It will be soon.
23 MEMBER DIMITRIJEVIC: You said that you 24 put it in October.
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217 1 outline of the guide. So we issued an outline to the 2 public along with a public meeting to solicit initial 3 comments just on what we were thinking of doing for 4 the draft guide. But the formal public comment period 5 has not started.
6 MEMBER MARCH-LEUBA: But you provided an 7 email where we could send you information.
8 MS. THOMPSON: Yes.
9 MEMBER MARCH-LEUBA: So as an interested 10 member of the public, I could send you anything I 11 want.
12 MS. THOMPSON: Yes.
13 MEMBER MARCH-LEUBA: And so I don't think 14 we need to write the letter if one member would like 15 to provide a comment.
16 On the long term, this has such limited 17 applicability. I mean, I've been looking at all the 18 volcanoes. Unless you want to go to Hawaii or Alaska, 19 that's about it. So I don't see a need to write a 20 letter.
21 CHAIR BLEY: Thank you.
22 Walt?
23 MEMBER KIRCHNER: Thank you for the 24 presentation, and I think we could wait until after 25 the public comment period. But I do appreciate the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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218 1 sentiment with Vesna to perhaps get the terminology 2 consistent with the PRA practice. Thank you.
3 CHAIR BLEY: Okay.
4 Matt?
5 MEMBER SUNSERI: So as I read through the 6 background material on this and the draft that already 7 got out, I was thinking to myself, gee, what an 8 eloquently straightforward seven-step approach to 9 address a very low-frequency event. This can't take 10 more than a couple hours to -- thank you for the 11 presentation. I found it very good and informative.
12 You all have done a lot of hard work. That's all.
13 And I don't think we need to write a letter at this 14 time. Maybe later.
15 CHAIR BLEY: Joy?
16 MEMBER REMPE: I'd like to sort of second 17 what Matt said. I think that the presentation and the 18 individuals involved with it were very well informed 19 and gave us some very good, helpful information, and 20 I appreciate their endurance and patience with our 21 questions. And so I think you deserve some 22 compliments on that.
23 I don't think we need to write a letter at 24 this time, but I do think that there were several 25 comments. Of course, they're just from individual NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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219 1 members, and I hope you'll consider, if you can, some 2 of it before it's issued for public comment.
3 In particular, as one member who shouldn't 4 be taking too much credit, I'm interested in if the 5 reg guide could even comment about other nearby 6 hazards that might be posed that were not evaluated 7 for volcanic hazards if that exists. Thank you.
8 CHAIR BLEY: Thanks.
9 Dave?
10 MEMBER PETTI: Yeah, I want to thank them.
11 They did a great job. I learned a lot. But I tend to 12 agree with Charlie. I think it's too early to write 13 the letter now. I would wait to see what happens with 14 ANS, and then I wouldn't necessarily say yes. I'd 15 just reevaluate at that point whether we need to have 16 a letter.
17 CHAIR BLEY: Thank you.
18 Ronald?
19 MEMBER BALLINGER: I guess I'm a little 20 bit torn because on the one hand, I don't think this 21 has -- this has very limited applicability. Like Jose 22 was saying, unless you want to build a reactor in 23 Alaska or Washington or Oregon, it's not likely to be 24 an issue.
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220 1 perceive this to be an issue that they're going to 2 have to deal with, the public comment period could get 3 pretty interesting. So I think, based on the public 4 comments, we may or may not want to write a letter.
5 I'm ambivalent on that.
6 But I think the applicants are going to be 7 looking for off-ramps that are very well defined with 8 finality. If those aren't there, then your public 9 comment period will get very interesting.
10 CHAIR BLEY: Thank you.
11 Our consultant, Steve?
12 DR. SCHULTZ: I also appreciate the 13 presentations and all the work that went into the 14 development so far, as well as what you described as 15 your early involvement with both the public as well as 16 applicants in the overall process. That is very 17 important.
18 And in that regard, the comments that have 19 been made this afternoon about trying to develop 20 elements of examples, I think, would be very helpful 21 going forward. And I'd be surprised if the public 22 comments don't also ask for that. So if you've got 23 time to get a head start on that, it might be useful, 24 certainly.
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221 1 that you stay in close-cut touch with the ANS 2 Standards Committee because you've got them on your 3 schedule, and they don't always complete their 4 standards when time is on calendar. So I think it's 5 important that that connection be made, but you might 6 need to lean on the Standards Committee's to make sure 7 it gets done on your schedule.
8 CHAIR BLEY: Mike?
9 DR. CORRADINI: I think the staff did a 10 very nice job. I personally think that the draft reg 11 guide is quite helpful in trying to screen it out. I 12 think the point about bringing examples into each of 13 those steps so that you can identify from a practical, 14 concrete basis what moves you on, what takes you off 15 the steps, would be very useful. And the more 16 specific those examples can be, whether they be 17 specific plants or specific installations, I think the 18 better off it would be.
19 My personal view still is that somehow, 20 somewhere in this, you're going to have to point to 21 some sort of go/no-go risk-informed value. Even if 22 you don't have one at this point, you at least should 23 recommend or at least acknowledge the fact something 24 at some time is going to have to be recommended, that 25 at some level, it's either from a relative risk NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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222 1 standpoint or an absolute risk standpoint. It's of no 2 consequence. Otherwise, this becomes a burdensome 3 activity.
4 CHAIR BLEY: Thank you. I'd appreciate if 5 any of the members or consultants have other things 6 that come to mind, drop me a note. I'd like to keep 7 them.
8 I'd like to thank you very much, and Brit 9 gave us a lot of good help along the way here. And 10 the whole staff who's been involved in this, I think 11 you've done a really great job of organizing it.
12 I think I'm concerned about the risk-13 informed part of this, the risk side of this, and I'm 14 pretty nervous about it. And I myself was leaning 15 toward an early letter rather than a late one before 16 things get cast in concrete. The standard, Lord knows 17 when that will get done. The last one that was in a 18 new area was the shutdown risk, and that took ten 19 years before it got voted out, at least ten. And this 20 is a new area for most people, so it could take a very 21 long time. So I think going ahead with it is good.
22 The applicability is rather limited, but 23 if you're going to use -- the structure is right. The 24 ideas are right. The specific way you use those steps 25 is you begin to quantify the two probabilities that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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223 1 you come up with. That's where it gets a little 2 fuzzy, and either I'll write something personally or 3 I'll circulate something, and we might want to write 4 a letter on this.
5 I'll play with my own notes and then see 6 what the subcommittee thinks later. And I'm not 7 turning loose of that just yet because I think there 8 are some things that just don't quite work right from 9 the risk-informed point of view and those steps 4, 5, 10 6 that just need a little polish.
11 In any case, thanks very much to everyone.
12 Thanks to the Committee and everyone else here. We 13 are adjourned.
14 (Whereupon, the above-entitled matter went 15 off the record at 5:09 p.m.)
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DG-1364 - Volcanic Hazards Assessment for Proposed New and Advanced Nuclear Power Reactor Sites NRC Staff Presentation to the ACRS Subcommittee February 20, 2020
Presentation Outline
- Background
- Overview of Volcanic Hazards
- Discussion of proposed approach for Volcanic Hazard Analysis (VHA)
- Harmonization with International Guidance 2
Volcanic Hazards Working Group NRC Staff
- Laurel Bauer, M.S.
- Luissette Candelario, M.E.
- Allen Fetter, Ph.D.
- Cliff Munson, Ph.D.
- Ed ODonnell, Ph.D.
- James Rubenstone, Ph.D.
- Gerry Stirewalt, Ph.D., C.E.G., P.G.
- Jenise Thompson, M.S., PMP Contractor/Consultant
- Brittain Hill, Ph.D.
- Miriam Juckett, M.S. (SwRI) 3
Why now?
- DOE was recently authorized to develop advanced reactor projects at the Idaho National Laboratory (INL); NRC will have licensing authority
- NRC has regulatory requirements to assess geologic hazards at a proposed site but has no specific guidance on acceptable approaches to assess volcanic hazards 4
Regulatory Requirements
- 10 CFR Part 50, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criterion 2
- 10 CFR 52.17(a)(1)(vi) for an early site permit and 10 CFR 52.79(a)(1)(iii) for a combined license
- 10 CFR 100.23, Reactor Site Criteria 5
Prior Reviews 6
Prior Reviews Columbia
- 217 km east of Mt. St. Helens
- Volcanic Ash Fall - Design and Operational Basis Event 7
Prior Reviews Trojan
- 55 km southwest of Mt.
St. Helens
- Licensing considered ash fall and debris flow
- Decommissioned in 1992 8
Prior Reviews Idaho National Lab
- TMI-2 and Idaho Spent Fuel Facility
- Eagle Rock Enrichment Facility
- Possibility of lava flows and ash fall hazards 9
Prior Reviews Yucca Mountain
- Preclosure (operational)
- New volcano screened out
- Ash fall could be mitigated
- Postclosure
- Likelihood of new volcano and consequences 10
Use of Prior Approach
- Staff questioned whether the past approach for volcanic hazards reflects NRCs principles of good regulation.
- Openness
- Efficiency
- Independence
- Clarity
- Reliability 11
Regulatory Analysis
- Staff considered five alternatives to assess the regulatory need
- Schedule, cost-benefit analysis, technical content and document control were additional factors under consideration
- Principles of good regulation and risk-informed decision making 12
Optimal Path Forward
- Regulatory Guide was the optimal path forward
- Includes harmonization with existing IAEA Safety Guide
- Mechanism by which to consider endorsement of consensus standards under development
- Multiple opportunities for public interactions 13
Goals of the Regulatory Guide
- Protect public health, safety, and the environment
- Open and traceable basis for regulatory decision making
- Appropriate burden on applicants, commensurate with risk
- Consistent with NRCs risk-informed, performance-based framework and prior licensing actions 14
Regulatory Guide Challenges
- No generally accepted approach for VHA
- Support both siting decisions and potential design bases
- Rare events, appreciable uncertainties on event timing and nature
- Wide range of demands from volcanic events, limited design analysis (except ash fall).
15
What are Volcanic Hazards?
- Volcanic Ash
- 0.001 to 2 mm
- Hardness comparable to most metals and alloys
- Conductive, esp. when damp
- 0.1 to 100 mg/m3 airborne common
- Lingers days-weeks www.utilityservice.net after eruption 16
What are Volcanic Hazards?
- New Vent Opening
- Ground deformation
- Lava flows
- Ballistics
- Tephra Fall www.librarieshawaii.org 17
What are Volcanic Hazards?
- Lava Flows
- Dense (2,500 kg/m3, 156 lb/ft3)
- Hot (1,000 to 1,200 C, 1,830 to 2,200 F)
- Heat capacity comparable to metals
- Flow rate can vary between 1 to 10 m/s
- Follow topography, lateral break-outs www.discovermagazine.com common 18
What are Volcanic Hazards?
- Pyroclastic Flows
- Hot (> 300 C (570 F))
- Deposit densities from 1000 to 2000 kg/m3
- Fast-moving (100s of m/s)
- Can travel 10s to 100s of km from vent
- Can overtop barriers 100s m high if large volcanoes.usgs.gov volume 19
What are Volcanic Hazards?
- Other hazards
- Debris flows
- Debris avalanches
- Earthquakes <M5
- Hydrothermal systems
- Volcanic gases
- Lightning volcanoes.usgs.gov 20
General Approach for VHA
- Gather information
- Initial screening**
- Detailed analysis of relevant hazards**
- Evaluate design bases**
- Develop mitigation approaches**
- Siting considerations
- Apply risk insights 21
- 1) Gather Initial Information
- Time Period of Interest
- Last 2.6 Myr (Quaternary Period)
- Consistent with Standard Review Plan (SRP) 2.5.1 (geologic site characterization)
- Captures uncertainties in timing and character of past volcanic events 22
- 1) Gather Initial Information
- Regions of Interest (ROI) for initial 320 km screening
- 320 km for surface hazards (i.e., SRP 2.5.1)
- For ash-fall hazards, extend to capture 2.6 Myr volcanoes that might affect design or operation of facility (e.g., SRP 2.5.1) 23
- 1) Gather Initial Information
- Tectono-magmatic Model
- Large-scale processes that control volcanism
- Only consider <2.6 Myr volcanoes that are consistent with model Hill (1991) 24
- 2) Deterministic Screening
- Volcano characteristics in ROI
- Analogues or models to reduce uncertainties
- Screen based on maximum distance hazard could travel from source 25
Screening Example Lava flow length (km) Favalli et al. (2011) 26
- 3) Initial Risk Insights
- Suite of information to support risk-informed safety decisions
- Risk-insight information
- Sensitivity in plant PRA
- Uncertainties
- Available alternatives
- Confidence in supporting investigations 27
- 3) Initial Risk Insights
- Assume SSC failure = 1 if hazard at site
- Evaluate results in PRA
- Consider risk-insight information, including uncertainty & alternatives
- If not significant to safety, document rationale and end VHA 28
- 4) Eruption or Hazard Likelihoods
- Can first evaluate either Probability of eruption (PE) or of hazard (PH)
- Character of past event may be more certain than timing
- Uncertainties from erosion, burial, interpretation, modeling etc.
29
Applying the SSHAC Process
- Staff endorses the use of the Senior Seismic Hazards Analysis Committee (SSHAC) process to calculate PE and PH in the VHA
- Determine center, body and range of the technically defensible interpretations
- SSHAC study level based on
- Source-term or fragility of proposed facility
- Completeness and accuracy of geologic record
- Number of hazards being considered
- Significance of alternative hazards models 30
- 4) Evaluate Eruption Likelihoods
- Challenges for PE 1955 Kilauea East Rift - Event definition
- Probability of occurrence, exceedance, or both?
- Uncertainties on timing and number of past events
- Potential non-stationary volcanoes.usgs.gov recurrence rates 31
- 4) Evaluate Hazard Likelihoods
- Challenges for PH
- Range of models, need for model support
- Character changes with distance from source
- Interpretations from preserved deposits
- Characteristics can change through time Ogburn & Calder (2017), fig. 7 32
- 5) Detailed Risk Insights
- Evaluate results in PRA
- Consider risk-insight information, including uncertainty & alternatives
- If not significant to safety, document rationale and end VHA 33
- 6) Evaluate Design Bases
- Optional Step
- Develop more accurate limit states for SSCs
- Exceedance likelihoods for hazard demands
- Actual material properties
- Facility-specific SSCs
- Re-evaluate risk insights
- Allows for enhancing design basis 34
- 7) Evaluate Mitigation Actions
- Hours to weeks of warning before eruptions
- Columbia NGS, WA
- Ash-fall hazard from Cascades, >200 km away
- Hours to prepare
- Air filtration, maintenance procedures
- Ash-fall is a commonly mitigated hazard world-wide 35
- 7) Evaluate Mitigation Actions
- Some surface flows have been mitigated
- Proposed actions
- Appropriate monitoring in place
- Clear alert levels
- Practicable actions in time available
- Re-evaluate risk insights with volcanoes.usgs.gov mitigation credit 36
Siting Considerations
- If hazard cannot be mitigated through design or operations, alternative sites should be investigated
- Volcanic hazards often are spatially restricted
- Sites with acceptable risk might be located within several km or less 37
Harmonization
- General consistency IAEA SSG-21
- Staged approach
- Screening
- Detailed VHA
- Graded to installation risk IAEA (2012) SSG-21 38
Alternatives to IAEA Approach
- IAEA considers some volcanic hazards as site exclusion criteria.
- Inconsistent with a risk-informed, performance based framework
- Inconsistent with probabilistic risk-insights
- IAEA requires licensees to conduct monitoring
- Inconsistent with USGS statutory role in USA 39
Future Plans
- Issue draft guide for public comment and interim use
- Solicit feedback from stakeholders on content and use of guide to develop application
- Staff involvement in ANS 2.34 working group
- Comments will be received and addressed throughout the process - VolcanicHazards-RG@nrc.gov 40
Timeline 2020 2021 2022
- RIC Digital
- Address
- ANS 2.34 Exhibit public Issued
- Issue DG comments
- Finalize and
- Public
- Consider issue RG Comments feedback from applicants
- Revise DG 41
Conclusions
- The draft RG on volcanic hazards is consistent with NRCs risk-informed, performance-based regulatory framework.
- The draft RG provides appropriate opportunities to evaluate the risk significance of potential volcanic hazards, and end the analysis if hazards are not significant.
- Although only a few sites in the US might need to evaluate volcanic hazards, the draft RG provides a practicable, open, and traceable approach that is appropriately protective of public health, safety, and the environment.
42