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Transcript of Advisory Committee on Reactor Safeguards - Regulatory Policies and Practices Subcommittee Meeting, February 16, 2023, Pages 1-99 (Open)
ML23066A075
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Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION

Title:

Advisory Committee on Reactor Safeguards Regulatory Policies and Practices Docket Number: (n/a)

Location: teleconference Date: Thursday, February 16, 2023 Work Order No.: NRC-2268 Pages 1-76 NEAL R. GROSS AND CO., INC.

Court Reporters and Transcribers 1716 14th Street, N.W.

Washington, D.C. 20009 (202) 234-4433

1 1

2 3

4 DISCLAIMER 5

6 7 UNITED STATES NUCLEAR REGULATORY COMMISSIONS 8 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 9

10 11 The contents of this transcript of the 12 proceeding of the United States Nuclear Regulatory 13 Commission Advisory Committee on Reactor Safeguards, 14 as reported herein, is a record of the discussions 15 recorded at the meeting.

16 17 This transcript has not been reviewed, 18 corrected, and edited, and it may contain 19 inaccuracies.

20 21 22 23 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com

1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 + + + + +

4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5 (ACRS) 6 + + + + +

7 REGULATORY POLICIES AND PRACTICES SUBCOMMITTEE 8 + + + + +

9 THURSDAY 10 FEBRUARY 16, 2023 11 + + + + +

12 The Subcommittee met via Teleconference, 13 at 1:00 p.m. EST, Vicki M. Bier, Chair, presiding.

14 15 COMMITTEE MEMBERS:

16 VICKI M. BIER, Chair 17 RONALD G. BALLINGER, Member 18 CHARLES H. BROWN, JR., Member 19 VESNA B. DIMITRIJEVIC, Member 20 WALTER L. KIRCHNER, Member 21 GREGORY H. HALNON, Member 22 JOSE MARCH-LEUBA, Member 23 DAVID A. PETTI, Member 24 JOY L. REMPE, Member 25 MATTHEW W. SUNSERI, Member NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

2 1 ACRS CONSULTANTS:

2 DENNIS BLEY 3 STEPHEN SCHULTZ 4

5 DESIGNATED FEDERAL OFFICIAL:

6 HOSSEIN NOURBAKHSH 7

8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

3 1 CONTENTS 2 Page 3 I. ACRS Subcommittee Chairman Opening Remarks 4 Vicki Bier . . . . . . . . . . . . . . . . 4 5 II. A Historical Perspective on Safety Goals 6 David Johnson . . . . . . . . . . . . . . . 7 7 III. Public Comment . . . . . . . . . . . . . . . 51 8 IV. ACRS Members Comments . . . . . . . . . . . . 55 9 V. Meeting Adjourned . . . . . . . . . . . . . . 76 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

4 1 P-R-O-C-E-E-D-I-N-G-S 2 1:00 p.m.

3 CHAIR BIER: Well we should go ahead and 4 get started, I think, because it is 1:00. So this 5 meeting will now come to order.

6 This is a meeting of the Regulatory 7 Policies and Practices Subcommittee of the Advisory 8 Committee on Reactor Safeguards, in preparation for 9 ACRS efforts exploring NRC safety goal policy. I am 10 Vicki Bier. I am Chair of today's Subcommittee 11 meeting.

12 Members in attendance, in no particular 13 order, Joy Rempe, Ron Ballinger. I believe Jose and 14 Charlie are both in the room there. I'm virtual so I 15 haven't confirmed. You both back?

16 MEMBER BALLINGER: Ron is.

17 CHAIR BIER: Okay, great.

18 MR. MOORE: This is Scott. This is Scott 19 Moore.

20 CHAIR BIER: Yes.

21 MR. MOORE: Jose will be back in a minute, 22 he just stepped out briefly.

23 CHAIR BIER: Oh, perfect. Thank you for 24 clarifying. Dave Petti, Walt Kirchner, Greg Halnon, 25 Vesna Dimitrijevic, Matt Sunseri. And then we also NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

5 1 have two consultants with us, Steve Schultz and Dennis 2 Bley. Consultants to the Committee.

3 Have I missed anybody that I should have 4 listed? Okay --

5 MR. MOORE: Did you mention Ron Ballinger 6 is here in the room as well?

7 CHAIR BIER: I think I did get his name --

8 MR. MOORE: Okay, thank you. Sorry.

9 CHAIR BIER: -- earlier. Oh, no problem.

10 MR. MOORE: My mistake.

11 CHAIR BIER: Thanks for clarifying.

12 Designated federal official for today's meeting is 13 Hossein Nourbakhsh. And there will be time for public 14 comment during the meeting, but people can also share 15 any feedback with him after the meeting.

16 We are holding this meeting to gather 17 information to support an ACRS working group exploring 18 the quantitative health objectives in the safety goal 19 policy. Right now this work is at a very preliminary 20 stage, so we are just focused on gathering information 21 and background.

22 We've invited Dr. David Johnson to present 23 a perspective on the nuclear safety goals. Dave 24 Johnson was an ACRS fellow at the time when the safety 25 goals were initially developed and proposed by the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

6 1 ACRS, working with David Okrent at that time.

2 And that work was the basis for the later 3 NRC development of the safety goal policy. So we 4 thought it would be interesting getting his 5 perspective on both the history of safety goals, but 6 he also has a lot of experience with PRA in the year 7 since then, and reflect some on how he sees the 8 current and future status as well.

9 The ACRS section of the U.S. NRC public 10 website provides our charter, bylaws, agendas, letter 11 reports and full transcript of all full and 12 subcommittee meetings, including slides, like what 13 Dave is going to present today. The meeting notice 14 and agenda for this meeting were also posted there.

15 The Subcommittee will gather information, 16 analyze relevant issues and facts and formulate 17 proposed positions and actions as appropriate for 18 deliberation by the full committee. A transcript of 19 today's meeting is being kept, and will be made 20 available.

21 Due to the COVID pandemic, today's meeting 22 is being held in hybrid mode, with both in-person and 23 remote Microsoft Teams capabilities. There is also a 24 phone bridge line number allowing public members to 25 participate over the phone as well.

NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

7 1 Anybody making comments to the 2 subcommittee should please first identify yourself and 3 speak with sufficient clarity and volume so that you 4 can be readily heard. When not speaking we request 5 that participants mute their computer, microphone or 6 telephone to reduce noise.

7 I think public comments are on the agenda 8 for at about 2:00 or 2:10 today. And we may get to 9 that a little earlier, but I will try and come back to 10 that at that time in case anybody is planning their 11 schedule around that.

12 And at this point we are ready to proceed 13 with the meeting. And I will call upon Dave Johnson, 14 our invited expert, to begin today's presentation.

15 Dave, you can go ahead.

16 DR. JOHNSON: Great, thank you. And 17 hopefully you can hear me clearly. I want to thank 18 Vicki for inviting me. And before I forget, I want to 19 say hello to Steve Schultz and Dennis Bley. And it's 20 been quite a while.

21 So, my comment, I guess, is any 22 relationship of the NRC goals to what the ACRS put 23 together is not real clear. I mean, it's clear but 24 it's just, the ACRS went much further in my opinion.

25 So, first a brief introduction. I want to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

8 1 walk through the history of the ACRS safety goals that 2 was published in 1980. And then touch on some safety 3 goals that my group developed for the research reactor 4 in Australia in about '98.

5 I've had the good fortune to work on 6 several research reactors from a PRA point of view.

7 And when I think back on them I think there is, we can 8 learn a lot from those activities as we move into new, 9 innovative or old designs, whatever you want to call 10 them, reactors that we're seeing come to fruition 11 right now.

12 Very gratefully on the NRC PRAs, just at 13 a high level how they were stated, et cetera. And 14 finally talk about the really challenging things you 15 guys have bitten off by trying to extend this work 16 into the area of SMRs and microreactors. You know, 17 I'm working on some great applications now. There is 18 just a whole new environment for us to consider these 19 days.

20 So, 1979, 1980 I was a fellow at the ACRS.

21 1979 I worked primarily with Dave Muller. And he and 22 David Okrent were my sponsors. 1980 I went over to 23 work with David, David Okrent.

24 So, what was the landscape at the time?

25 There was a limited number of PRAs, we'll call it NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

9 1 PRAs, available at the time. Certainly the WASH 1400 2 final report, 1975. Oyster Creek in '78 came out. A 3 kind of concurrent with a lot of this work between the 4 Zion and Indian Point studies. And you'll see I 5 pulled from some preliminary Zion work to think 6 through some possible metrics for their safety goals.

7 I have got to say, the attitude in RCA 8 regarding PRA, I'll be kind say it was mixed. There 9 was a large number of people who didn't understand PRA 10 and were embedded with the deterministic thinking.

11 There is some very strong support with Bob Budnitz's 12 role, et cetera. But there is quite a bit of 13 hostility to trying to use PRA in anything that kind 14 of felt like a regulatory environment.

15 And in the background of our work TMI had 16 just occurred. You know, the ACRS at the time was 17 located downtown. And about a week after I got there 18 an event happened up at Maine Yankee, just a 19 calculational error was found in a computer code and 20 it resulted in hearings on the Hill. ACRS sent a GS-21 15 down there to gather up all the material and take 22 notes, et cetera.

23 And I moved my big mouth and, gee, if 24 anything like this happens again I'd love to do that.

25 Well, TMI happened about a week later, so I spent way NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

10 1 too much time listening to those folks. It's very 2 disheartening to see how our laws are made quite 3 frankly. Young people shouldn't do that.

4 Also kind of in background, there is 5 inconsistent federal guidelines. There are radiation 6 exposure limits in the laws which, let me just say, 7 were science-based. Or at least science argued.

8 And then we had the Delaney Clause which 9 at the time said, gee, if there is anything from an 10 animal study or actual regulatory data, et cetera, 11 that says that this is cancer causing materials it 12 will not be in food, drugs or cosmetics. So there is 13 an absolute limit, if you will. That's since been 14 changed. Modified to something more reasonable. By 15 the time that was the law.

16 So we were trying to, one of the things we 17 did was look at the landscape of what other issues has 18 the government sunk their fingers into. And those 19 kind of represented the two extremes, if you will.

20 Inconsistent.

21 So I'm trying to duplicate what the cover 22 of the NUREG that we produced looked like. At least 23 at that time the ACRS, when they approached me, came 24 out with these Orange colored covers. They spelled 25 the word committee correctly. I didn't when I made NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

11 1 this slide up.

2 So the folks working on these goals were 3 Mike Griesmeyer, myself. Bill Kastenberg did a 4 sabbatical. But these here have some, of course the 5 main driver behind this is David Okrent. You can see 6 his fingerprints throughout the framework and the 7 structure of the goals.

8 So one thing that I think I missed along 9 the way, and I tried to pull up the relevant sentence 10 there on top, you know, it's almost as if the 11 Committee wrote these notes. The NRC rules and 12 regulations, and staff documents dealing with safety, 13 such as reg guides, et cetera, et cetera, represent a 14 risk reduction philosophy without fully articulated 15 safety goals.

16 So in other words, there is no framework 17 for NRC to really consider the work that they were 18 doing to establish and maintain safety. It seemed to 19 be, gee, let's make things safer and safer and safer.

20 So the primary goal of the committee, 21 there in black, was to provide NRC with a coherent 22 framework for effective regulation. You know, it 23 wasn't to add more regulatory issues for the 24 licensees, it was really to provide guidance for the 25 NRC.

NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

12 1 And I'll say this a couple of times, the 2 goals, or objectives, whatever words we're going to 3 use, were not considered absolute when viewed in 4 isolation. I think the words in there say that the 5 plant would be expected to not exceed the limits in 6 the long-term, but there could be excellent reasons 7 for limits to be exceeded.

8 For example, you know, at the time I think 9 we used an example of the time in New England there is 10 a number of nuclear plants at the time. And if it was 11 an exceptionally cold winter, in closing down one or 12 two plants would cause hardship, or maybe even health 13 effects or deaths in one population, certainly they 14 would not closing down plants in the short-term. So 15 these were to be used, these were not to be viewed 16 isolation onsite.

17 So, a couple of forms of the decision 18 rules. One that there are limits on certain hazardous 19 states within the reactor. We'll get to each one of 20 these. The limits on individual risk or early death 21 or delayed death due to cancers. In societal risk of 22 early death or delayed deaths due to cancers.

23 And you'll see it when we articulate the 24 goals for the societal risks, there is a major risk 25 aversion in that criteria. David Okrent was a big NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

13 1 believer in risk aversion. We talked a lot about it.

2 You know, that's the philosophy that 3 society has expressed a willingness to bait one bus 4 crash that kills ten people more, or higher, a worse 5 event if you will, than ten bus crashes that kill one 6 person each. So that's a, you'll see a risk aversion 7 factor sneak in here. ALARA was always present in 8 these considerations.

9 Assume that the cancer deaths, and early 10 deaths, would control radiological releases. And 11 there other impacts that we can talk about. We talked 12 about teratogenic effects, but we're only going to put 13 early deaths and cancer deaths into the puzzle here.

14 So, there is a lot of library work done 15 leading up to this work. There is a great body of 16 research done in the '60s and '70s on issues of 17 acceptable risk, and things like that.

18 Now I just pulled out of a few of them 19 here. Adams and Stone said, gee, the changes in the 20 risk ought to be small compared to the demographic 21 variation, this happened to be in the U.K., from risk 22 for dying of all other hazard sources. And so that 23 leads you to something like ten to the minus five per 24 year for an individual.

25 Kind of the classic case was a Farmer and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

14 1 the Farmer Curve. There was a frequency release 2 curve, a frequency of curies of iodine if you will.

3 And my understanding is this came about at a response 4 to the once fatal accident when they were trying to 5 find a rational basis for how far do we need to go out 6 and interdict the sheep and livestock to protect the 7 health and safety of the public. But this is a 8 classic case of risk acceptance, or risk measurement, 9 if you will.

10 Bowen I liked quite a bit because it 11 emphasized that the risks ought to be smaller than the 12 benefits gained by the technology.

13 DR. BLEY: Hey, Dave, can I interrupt you?

14 DR. JOHNSON: Yes, sir. Dennis.

15 DR. BLEY: My memory might be off on this.

16 This might have been somebody else applying Farmer's 17 work. But I thought the Farmer Curve had a knee in it 18 to throw in some risk aversion effects too?

19 DR. JOHNSON: Yes. It's not -- I believe 20 it does. It does have a risk aversion effect, but it 21 did have a knee in it. I didn't know the source 22 event. And I no longer have a copy of the curve 23 itself. So that's a good point.

24 So on the risk being smaller, damaged by 25 the technology, I was going to talk more about this at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

15 1 the end, and I just kind of ran out of time. I 2 figured you'd be tired of me talking by then.

3 But we're talking about some of the new 4 nuclear applications being connected to specific 5 technology such as reducing ammonia for fuel or 6 hydrogen for fuel. And if you can imagine 800 degrees 7 sea steam going into an industrial building, you know, 8 where do you draw the limits in terms of doing the 9 risk assessment for this process.

10 I just became aware of an environment 11 defense counsel's paper. It's peer reviewed, it's way 12 outside my field, that suggests that hydrogen being 13 very hard to contain, which is true., if it were to 14 get up into the upper atmosphere it could be the 15 granddaddy of all carbon issues or, what am I trying 16 to say, climate change gases that we've ever released 17 in our life. So, we could be rushing into things not 18 knowing.

19 So the risks, we need to keep in the mind 20 the risks that we're setting aside. You know, maybe 21 sticking with replacing old coal plants might be a 22 thing to do.

23 And finally I just want to mention, the 24 benefit for me is with a number of experiments. But 25 the two that really stuck out of my mind were Bill NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

16 1 Lowrance who had just finished a book called, Of 2 Acceptable Risk. And talked about how people in 3 societies understand, grow to understand risk. And 4 neither accept them or put them into special 5 categories.

6 And Paul Slavic who really kind of helped 7 straighten out ideas with risk perception when it came 8 to technical risks.

9 So, we explored a number of different 10 methods. Let me drink water here. And one that was 11 violently rejected by a committee member who, up until 12 that time was a very mild manner guy in my book.

13 So I presented an idea that really started 14 with the question of, why is it we do PRA. And I 15 thought there at the time my thinking was, there was 16 two key reasons. One is to come up with a rank 17 ordered list of scenarios that contribute to something 18 bad and understanding where those scenarios came from, 19 what you can do about them, and that sort of thing.

20 And the second thing is to really identify 21 and understand sources of uncertainty. You know, 22 we're dealing with large uncertainties in the case.

23 So I thought it would be prudent to talk 24 about a metric that really focused on uncertainty.

25 And what I did, the best PRA that I could put my NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

17 1 fingers on at the time was Zion. At least a very 2 preliminary version of Zion. This is not what the CDF 3 for Zion looked like, that's what I was able to 4 recreate for this presentation.

5 But I thought, well, why don't we put some 6 sort of measure on the median value of this metric 7 CDF, then something adding a tail. And I know the 8 95th was getting kind of swirly, and I arbitrarily put 9 the 85th. And when I said they were arbitrary that's 10 when the, Jeremiah Ray was the, who was my old member 11 who went berserk, anyway, there is, committee enjoyed 12 this presentation. But they basically backed off and 13 accepted Jeremiah's recommendation that we not do 14 something explicitly with uncertainty curves.

15 And I really thought that we missed an 16 opportunity there because, in my reading, uncertainty 17 gets a lot of lip service but is not really focused 18 on, as a keen interest.

19 So anyway, the two numbers from Zion, that 20 would be ten to the minus four and eight times ten to 21 the -- five times to the minus 85th. And you'll see 22 those numbers again here pretty soon.

23 So was left, you know, after the, the my 24 wounds healed up, what we decided to do was take those 25 two numbers, in the middle of column, middle row here, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

18 1 field damage, and use the smaller one to set a goal of 2 one times the last four, and the upper one as a limit.

3 And in-between it's kind of business as usual. You 4 know, there is, it's kind of fuzzy, if you will.

5 And I can tell you when Reg Guide 1.174 6 came out they used this same kind of framework and 7 growth once more. But the argument was by accepting 8 a range we're kind of embracing uncertainty. And I 9 actually still don't believe that.

10 And the other goal, was has not been used 11 anywhere that I can see, is what is called significant 12 core damage. But basically noble gases and things 13 like that. About a factor of three more often, if you 14 will, than the large scale fuel damage.

15 Now why it might be of particular interest 16 these days, although it's a more complex issue, is 17 that, I'm thinking that your goals, let's say your 18 framework today, is going to have to embrace a number 19 of different technologies. Including molten fuel 20 reactors. Okay?

21 And we know the molten salt reactor 22 experiment at Oak Ridge had a special system that 23 gathered up the noble gasses (audio interference) and 24 not have a significant issue with the core itself.

25 So, there may be a different category of events that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

19 1 we need to consider.

2 And finally, the last row is we've seen is 3 a sort of conditional core damage -- conditional 4 containment, if you will. And once again, I want to 5 emphasize that everything the committee did indicated 6 that compliance with the upper limit was anticipated.

7 And it was required for extended operation. But there 8 could be reasons where a plant could operate outside 9 this framework for a period of time.

10 So for individuals, the most exposed 11 individual, there is limits on the cancer, cancer 12 deaths, as well as early deaths due to accidents. And 13 this was over the lifetime of the reactor. And 14 considering all reactors at a particular site.

15 So, I won't go through read the goals 16 here, but you'll see that the goals are specified, 17 both in terms of goals and limits. You know, 18 something on the order of ten to the minus five-ish.

19 Or ten to the minus something times seven to the minus 20 six.

21 For reference, individuals at the time, 22 the best data we had the time, individuals with cancer 23 death risk was something on the order of 15 or 20 24 percent. I'm not sure what it is today. It could be 25 more or less. But anyway, the message here is it's a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

20 1 small increment to existing risks due to cancer.

2 Likewise for early deaths, the numbers 3 were in the order of ten to the minus six, five to the 4 minus six, et cetera. And for reference, the safest 5 demographic to be, again, at the time, this was 6 probably data from the, oh, '60s and '70s would be a 7 14, a 10 to 14-year-old-girl with having an accidental 8 death rate of about ten to the minus four.

9 Likewise, societal risks were specified in 10 terms of the goals and limits. I won't go through 11 here, but just pointing out that the accidental deaths 12 were specified with a risk aversion with Alpha. With 13 is the exponent in the equation, of 1.2.

14 We did do --

15 MEMBER KIRCHNER: David?

16 (Simultaneous speaking.)

17 MEMBER KIRCHNER: Dave, this is Walt 18 Kirchner.

19 DR. JOHNSON: Yes, sir.

20 MEMBER KIRCHNER: Could you just explain 21 this chart? This is interesting because it references 22 kilowatt hours. Could you just elaborate a little 23 more how this was developed?

24 DR. JOHNSON: I could if I remembered.

25 Let me just think for a second. I was looking at it NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

21 1 this morning and was trying to figure out a couple 2 aspects of this, but quite frankly I don't recall why 3 we choose that metric.

4 MEMBER KIRCHNER: Well, it looks like the 5 integrated power that was produced by the reactor 6 fleet --

7 DR. JOHNSON: Yes.

8 MEMBER KIRCHNER: -- or at a site or --

9 DR. SCHULTZ: Dave?

10 DR. JOHNSON: Yes.

11 DR. SCHULTZ: Dave, this is Steve Schultz.

12 Ten to the 10th kilowatt hours is approximately one 13 year of reactor operation at 1200 megawatts.

14 DR. JOHNSON: Yes.

15 DR. SCHULTZ: Yes.

16 DR. JOHNSON: I did figure that out. I 17 don't know why we choose to express it in those terms.

18 So --

19 MEMBER PETTI: Is it because it's related 20 to a fraction of the cancer? A fraction of the deaths 21 from coal?

22 DR. JOHNSON: Well, it was, we did compare 23 it to what we thought were the best estimates for 24 coal. That may have been the reason why we went to 25 kilowatt hours. But it's a little confusing here to NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

22 1 represent this one in terms of kilowatt hours when the 2 other charts were not this way. I do not know. A new 3 and smarter committee can clean this up.

4 (Laughter.)

5 CHAIR BIER: But that is a very 6 interesting bit of historical background we can 7 probably dig out. The source for that and some of the 8 documents at the time. Maybe not the rationale but at 9 least the precedent that it was based per --

10 DR. JOHNSON: It could be one of the 11 appendices to the NUREG --

12 CHAIR BIER: Yes.

13 DR. JOHNSON: -- as an attempt to apply 14 the goals, if you will, to a coal plant. And I just 15 summarized that at the bottom is, you know, the same 16 metric applied to a similar status coal plant would 17 result in --

18 CHAIR BIER: Right.

19 DR. JOHNSON: -- it says 10 to 200 excess 20 deaths per year.

21 CHAIR BIER: So I have been trying to 22 collect a little mini library of documentation of the 23 historic analysis, so I will try and see if I can dig 24 that out.

25 DR. JOHNSON: Yes. There is, I believe NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

23 1 quite an extensive bibliography in the NUREG.

2 DR. BLEY: Hey, Dave? It's Dennis. Just 3 two quick things here. The one is, like everybody 4 else pointed out, you did a comparison essentially 5 with a coal plant running for a year.

6 There is a bit of a story that the goals 7 were set to be a fraction of a coal plant's output.

8 And maybe that's not the right thing to do these days, 9 but --

10 (Simultaneous speaking.)

11 DR. BLEY: -- really saying it comes from 12 other sources, and you just did a comparison with coal 13 plants to see how they --

14 (Simultaneous speaking.)

15 DR. JOHNSON: Yes.

16 DR. BLEY: -- stood up again.

17 DR. JOHNSON: -- we started off thinking 18 that it would be appropriate to get a closer 19 comparison to coal plants. And that may make that be 20 the driving factor, if you will. But we soon realized 21 that the coal plant data we had was publicly coal 22 technology from the 1960s.

23 CHAIR BIER: Right.

24 DR. JOHNSON: And, you know, things, that 25 will change. And is it really fair to make that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

24 1 comparison anyways.

2 And if I backed up several slides the 3 literature seem to aim you toward if you're 4 establishing a new technology to make the incremental 5 risks to be very small compared to things like the 6 variation of nature and other risks or essentially 7 non-traceable. You know, non-observable. It would be 8 an analytical number if you will.

9 So we decided it was not fair to really 10 kind of point a finger and say, look the coal plants 11 are worse, we can do this and that, when we felt that 12 the technology itself had some very inherent 13 attractive features from this point of view. But I 14 think it is appropriate to make a comparison, but not 15 to base the limits on other technologies. If that 16 makes sense.

17 DR. BLEY: It does to me. And it kind of 18 clears the argument that's been floating around.

19 DR. JOHNSON: We talked about a, you know, 20 basing it on coal. That was one of their only 21 discussions. And it may have been the reason why we 22 wrote a separate appendix on the document that 23 actually did that comparison.

24 We didn't, you know, we didn't want to 25 alienate -- first of all, our audience for this was NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

25 1 not to put additional requirements on the 2 owner/operators of power plants, it was to help 3 provide NRC with a framework to kind of organize their 4 regulations. But we didn't want to survive the 5 feedback that if we were telling a company that had, 6 at an earlier plant, that, gee, that one of there was 7 lousy.

8 It was not our business, okay? We didn't 9 want to get into that argument. We didn't have to.

10 It turns out we didn't have to. We probably spent way 11 too much time worrying that through, but.

12 DR. SCHULTZ: Dave, this is Steve Schultz.

13 Just to comment. This is, 1980 was just about the 14 time that EPRI was spending a lot of effort looking at 15 scrubber technology of coal.

16 DR. JOHNSON: Right. Right. Yes, the 17 coal plants, you'll see the data in that appendix from 18 is, I would say at best '60s technology. Maybe even 19 earlier than that. They've come a long way. It would 20 not have been good to tie your reference to a moving 21 target.

22 So just a last couple of comments here.

23 There is a lot of good stuff, and I went back and read 24 this document, I hadn't read it in years and years.

25 Some additional requirements, special attention should NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

26 1 be paid to the delay of the PRAs. Full and explicit 2 duplication of assumptions and limitations. And peer 3 reviews must be done.

4 Well, this was 1980. You know, 15 years 5 later the PRA procedure's guide, not procedure guide, 6 but standards come out. And these are key elements of 7 that. So, early on the Committee was calling for that 8 sort of thing.

9 There is an additional discussion in 10 there. And this has got Dave written all over it, is 11 we really ought to establish a risk certification 12 panel that would have statutory authority to make 13 judgements, technical judgements on technical issues.

14 He was a great believer in science court.

15 I'm not sure it would have ever been a good idea given 16 our politics.

17 DR. SCHULTZ: Yes.

18 DR. JOHNSON: But he was adamant that the 19 people who say that the PRA is good need to have 20 specific qualifications. And in his mind, even 21 statutory authority to say so. I don't think we've --

22 DR. BLEY: So that idea, and EPRI is the 23 volunteer, Chauncey Starr was a big fan of that as 24 well as I recall.

25 DR. JOHNSON: Absolutely. Yes.

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27 1 MEMBER REMPE: So thanks for interrupting 2 me. Did it go beyond nuclear?

3 People do risk assessments for his plants, 4 did he want it to be an across the board or just in --

5 DR. JOHNSON: Oh --

6 (Simultaneous speaking.)

7 DR. JOHNSON: The science court would be 8 across the board. It would be --

9 MEMBER REMPE: Okay.

10 DR. JOHNSON: -- technical issues that 11 affects society.

12 MEMBER REMPE: It's interesting. Thanks.

13 DR. JOHNSON: And I, you know, the problem 14 of course is, that Dennis and I could come to an 15 agreement who should be on that panel. And we 16 disagree with anybody who disagrees with us. So 17 that's a tough one, tough one.

18 MEMBER REMPE: Okay.

19 DR. JOHNSON: But the idea that the 20 qualified loop is to have that say it's still a viable 21 one.

22 Okay, just the last slide on the 23 historical stuff. Really, on the individual cancer 24 deaths where it's explicitly considered for all 25 reactors at a given site.

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28 1 I don't know why we did that quite 2 frankly, but that's in there. And while the Zion PRA 3 is best I can find at the time, it's full scope, 4 internal events, external events, Level 3, things like 5 shutdown were not appreciated and not included in 6 that.

7 (Off-microphone comments.)

8 DR. JOHNSON: Well, on one hand we've made 9 (audio interference) -- was there a question?

10 MR. MOORE: This is Scott Moore, executive 11 director. No, there wasn't a question, that was the 12 court reporter saying --

13 DR. JOHNSON: Oh.

14 MR. MOORE: -- that he couldn't hear your 15 delivery because somebody else is on line.

16 DR. JOHNSON: Okay.

17 CHAIR BIER: Yes.

18 MR. MOORE: Has a mic open.

19 CHAIR BIER: So if you want, Dave, you can 20 go back and repeat your last sentence or two of 21 points.

22 DR. JOHNSON: Okay. So, all I was saying 23 is that, for whatever reason, and I don't remember the 24 rationale at this point, but only individual risk and 25 cancer death was considered for all reactors at a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

29 1 given site. I'm not sure why we did that. In 2 reflection it doesn't seem to be consistent.

3 And then I was saying that while the Zion 4 PRA was the best thing I could put my fingers on at 5 the time, it was a full scope PRA. Really state of 6 the art, Level 3. It did not include things like 7 shutdown risk. Later on I'm going to bring up the 8 role of security risk. We certainly didn't include 9 that.

10 And while advancements have been made in 11 things like fire PRA and that sort of thing, I happen 12 to think that the way that they treated human error in 13 the Zion PRA is at least as good as the way that 14 standard approaches are now. But that's just my own 15 opinion.

16 Anyway, things have changed since then.

17 Coal located technologies were not considered. I 18 think that could be an issue when you guys are moving 19 forward. And while coal provided a benchmark for some 20 measures, nothing that we built the limits and goals 21 off of, but coal is referred to in there. Nuclear 22 replacing existing technology is not considered.

23 And based on --

24 CHAIR BIER: Dave?

25 DR. JOHNSON: Yes.

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30 1 CHAIR BIER: There's a question from Joy 2 when you're ready for it.

3 MEMBER REMPE: This is Joy. And I wanted 4 him to finish the slide, but I do have a lot of 5 questions here.

6 CHAIR BIER: Okay.

7 MEMBER REMPE: But go ahead, Dave. Sorry 8 for --

9 (Simultaneous speaking.)

10 DR. JOHNSON: -- almost finished. I'll 11 just finish the slide. And I, it's my pet peeve, but 12 I think we missed a great chance to provide the 13 appropriate amount of attention in the PRA world to 14 uncertainty. Okay, I'm ready for your question.

15 MEMBER REMPE: Okay. Because you're going 16 to switch topics, I have some other questions that I'm 17 just curious and I'd like your insights a little bit 18 more.

19 When they were thinking about this, and as 20 you look at the hindsight thing, I'm curious if you 21 had any more insights on why that multiple units were 22 only considered with the individual risks. Could you 23 talk about, did they think at all about land 24 contamination?

25 DR. JOHNSON: No. No.

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31 1 MEMBER REMPE: Psychological risks? And 2 then finally, when they were formulating this, did 3 they think about what might happen if folks wanted to 4 change it in the future and the effects on regulatory 5 stability?

6 Because one of my thoughts is we, we're 7 just gathering information. It's not clear we're 8 going to come up with any great ideas that might help 9 with some of the non-LWRs or other kinds of 10 technologies, but what has used this framework for 11 making decisions for cost benefit types of changes.

12 And was the ACRS smart enough back when they did this 13 to think about, once you do this, what if you wanted 14 to make changes?

15 And so, I've got a lot of questions, but 16 I've been holding them back as this was the place 17 where I wanted to bring them up.

18 DR. JOHNSON: So, on the other 19 measurements, like land contamination, et cetera, so 20 the only offsite, that measurement was the early 21 deaths and cancer deaths. Like I said, we didn't 22 consider genetic effects, teratogenic effects, et 23 cetera. Land contamination. Those were not 24 considered without, you know, we just said we didn't 25 consider them.

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32 1 Maybe they ought to be the primary 2 considerations. And given what we learned in 3 Fukushima, maybe the land contamination ought to be a 4 primary measurement. I mean, that's an excellent 5 point.

6 In terms of regulatory stability, that was 7 not discussed. We were trying to get NRC focused on 8 regulatory, what's a polite word. Rationale. We're 9 just trying to get it stabilized. In other words, 10 every, not every, but it seemed like many of the 11 regulations that would get propagated, were propagated 12 because, let's do it because we can do it without any 13 rationale of why it is we're doing that, well really 14 it was the right thing to do or, you know, or we're 15 causing a bigger problem somewhere else.

16 So I can tell you regulatory stability was 17 not there. It was regulatory, a regulatory framework 18 to provide some sort of coherent rationale behavior on 19 the part of NRC.

20 MEMBER REMPE: So, again --

21 DR. JOHNSON: Does that --

22 MEMBER REMPE: -- I'm kind of throwing a 23 lot of things at you, but they were aware of the fact 24 that you have Peach Bottom with several units, and 25 some of the other plants with multiple units and they NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

33 1 didn't think about, except for this individual risk, 2 to consider all of the reactors at site.

3 DR. JOHNSON: No, that was --

4 MEMBER REMPE: They did --

5 DR. JOHNSON: That was not thought of 6 deeply, other than we need to consider the whole of 7 the facility there. I don't think we understood that 8 it's possible to have multiple acute accidents at the 9 same time, which I think we understand that's possible 10 now. So it was probably, you know, shoot, we ought to 11 be looking at the long-term effects perhaps.

12 Those are good points. And I think maybe 13 we need to go back and start with a fresh piece of 14 paper and consider that. I was certain --

15 (Simultaneous speaking.)

16 MEMBER REMPE: -- know what you were 17 thinking --

18 DR. JOHNSON: -- I was certain --

19 MEMBER REMPE: -- at the time, so I 20 appreciate it. But go, I didn't mean to interrupt you 21 I thought you were done. Go ahead.

22 DR. JOHNSON: No, no. I would certainly 23 support the idea of land contamination being a primary 24 measurement, if you will.

25 MEMBER REMPE: Thank you. Again, I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

34 1 appreciate you coming in and talking with us today.

2 DR. JOHNSON: You know, I need to point 3 out that I haven't slept since then. So it's not, 4 this is 43 years ago.

5 (Laughter.)

6 MEMBER REMPE: I have problems with things 7 too in the past. Thank you.

8 MEMBER KIRCHNER: Dave, this is Walt 9 Kirchner. Just an observation on that last slide. I 10 guess co-located technologies weren't explicitly 11 included, but they are indirectly, even back then, for 12 the citing of the plants. You did have to consider --

13 DR. JOHNSON: Oh, no, absolutely.

14 MEMBER KIRCHNER: -- nearby, nearby 15 hazards and so on that would potentially, well, you 16 just designed by either citing distance and/or 17 hardening of structures to withstand glass and other 18 effects. So, indirectly, I'm just highlighting that 19 because now we have concepts that are considering 20 hydrogen generation.

21 DR. JOHNSON: But you --

22 MEMBER KIRCHNER: And in the past, what 23 you wanted to do is put as much distance between your 24 power plant and, let's say gas lines and other 25 potential blasts or hazards, so that they're kind of NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

35 1 indirectly considered in, as a contributor to a 2 potential Level 3 PRA. Just an observation.

3 DR. JOHNSON: No, no, you're absolutely 4 right. They're considered in the sense of, how can 5 these technologies harm my plant. I'm thinking here 6 is, how can the plant intimately connect in with a 7 different technology, have some problems that we 8 didn't consider historically.

9 And I'm kind of jumping ahead in my mind 10 I guess when I wrote that because I'm working with 11 some people that are considering exactly that type of 12 connection.

13 Okay, I'm behind the curve here so let me 14 go through this one pretty quickly. Just to say that 15 a number of years later working in Australia, on their 16 research reactor there, is the last DIDO class reactor 17 around. So they're an old, old reactor.

18 Ten megawatts thermal, heavy water cooled, 19 heavy water moderated, graphite reflected. Light 20 water, secondary circuit was light water. And the 21 ultimate heat sink was basically evaporation into the 22 atmosphere. It was high enriched uranium fuel. So 23 the fuel was kind of touchy, if you will. Changed to 24 low enrichment in 2006. Shutdown 2007. I don't know 25 if it was two observations or independent.

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36 1 We did the PRA in '98, along with a 2 probabilistic remaining life study since it was such 3 an old plant. And so, it was what we called a (audio 4 interference) PRA. It looked at fuel damage for 5 different sources plus characterizing the state of 6 containment.

7 And so, they wanted a rationale for what 8 kind of numbers to throw out there. And these would 9 be more fuel damage numbers because that's the only 10 thing we'd be looking at. At the time OECD, you know, 11 was throwing out goals of ten to the minus four, ten 12 to the minus five.

13 As of that time, as of November '95, 14 something like 14 of 77 plants in the U.S. reported an 15 informal, reported CDFs greater than informal limit of 16 ten to the minus four.

17 And the other research reactor risk 18 assessment of any, that I knew about at the time, 19 well, that's not true, U.K. had one also. But when we 20 did it in HIFR was a 100 megawatt plant changed to 85 21 megawatts. But it had a CDF around, in the low minus 22 fours in the plant.

23 DR. BLEY: Hey, Dave?

24 DR. JOHNSON: There was -- excuse me?

25 DR. BLEY: Just, for the members, that one NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

37 1 being a much higher ought not be a surprise because as 2 I recall that machine was expected to have a core 3 damage accident every couple of years when they first 4 designed it.

5 DR. JOHNSON: Yes, I can talk for an hour 6 and a half on that. I'm still working on that one.

7 But HIFR had just, well, not just 8 completed, but a month or two ago completed a 500-fuel 9 cycle. So, fuel lasts about 26 days there. It's an 10 incredible machine. It's aluminum-based fuel with a 11 U308 and aluminum matrix. The 550 fuel plates are 50 12 mils thick. The cooling channels are 50 mils. The 13 power density is something like a megawatt a liter 14 with aluminum fuel.

15 So yes, when they, if you look at the 16 primary system, it's incredible robust, thick. And 17 the reason is, they didn't know whether the fuel would 18 hang together or just plate out on the primary system.

19 And they'd fix it and start up again. So it's an 20 incredible machine. A very important machine from a 21 research point of view.

22 The first one where we did a fuel 23 manufactured risk assessment for it. Which was kind 24 of incredible.

25 But you can divert my attention by getting NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

38 1 me to talk about HIFR all day. But so, just for a 2 reference, if you will, it was easy to talk to the 3 Australians about goals and limits and guides and 4 things like that because they have a framework for 5 risk acceptance, if you will, for essentially any 6 activities that you can think of. And this is taken 7 from one of their charts like, the U.K. does this too.

8 And I'm just happy that old age housing 9 has got the least risky measure there. I'm getting 10 into that time frame.

11 The reason I really wanted to bring this 12 up is that we developed guidelines for the specific 13 technology and the specific activities that were going 14 on. True. True we have limits that we argued for 15 damage to the, damage frequency to fuel in the core or 16 fuel in a closed in storage block with reasonably 17 fresh fuel. And fuel in a different storage block 18 with and without containment failures et cetera.

19 But we noticed a number of other 20 activities that they performed there that can lead to, 21 I would call it more unanalyzed conditions.

22 Mechanical damage to one or more fuel elements. They 23 move these fuel elements during power operation. What 24 they call flask. A heavy object that they move over 25 storage fuel, et cetera.

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39 1 And since it's a heavy water plant, 2 tritium is an issue. It should be contained in a 3 primary system, but historically they've had heat 4 exchanger leaks getting some of the material into the 5 secondary system. Which is essentially evaporating in 6 the air.

7 And I didn't want to present their 8 results, but I can say that it was the tritium 9 releases that, to the environment, that exceeded the 10 goals that we agreed on before we did the study. But 11 here's a plant that's a lower power level, wise power 12 level. Low primary system pressure, but with limited 13 analysis for a number of reasonably interesting 14 scenarios. So we put specific limits, if you will, 15 frequency of those scenarios coming to pass.

16 And that could be a useful mechanism going 17 forward when we're looking at oddball different plants 18 in the future.

19 I think I only have one slide --

20 MEMBER KIRCHNER: Dave?

21 DR. JOHNSON: Yes.

22 MEMBER KIRCHNER: Dave, before you go on.

23 This is Walt Kirchner again. It's interesting that 24 that reactor, it's graphite moderated, heavy water 25 moderator, heavy water secondary?

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40 1 MEMBER PETTI: It's beryllium moderated I 2 think.

3 MEMBER KIRCHNER: Beryllium moderated.

4 DR. JOHNSON: It was --

5 (Simultaneous speaking.)

6 MEMBER KIRCHNER: Did you uncover in your 7 analyses, Dave, that there is the potential for it 8 being over moderated?

9 DR. JOHNSON: We did not.

10 MEMBER KIRCHNER: Wow. I was just 11 wondering whether that, one of those scenarios might 12 have come up in your PRA work for that particular 13 design. Which would lead to a reactivity insertion I 14 assume.

15 DR. JOHNSON: Well this has to be one 16 reference that I do have. Like I said to Vicki. I'm 17 going to say we did not, but I'm not, I would have to 18 go back and search the report.

19 MEMBER PETTI: As I recall, a mechanical 20 damage aspect. I mean, they've had problems at the 21 HIFR and other reactors of similar ilk with the fuel.

22 I mean, it sits on the edge. The margin to damage is 23 not, you know, it's not very large. Just because they 24 need the high neutron flux and that's part of the 25 mission. You -- there's acceptable risk that's NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

41 1 different.

2 DR. JOHNSON: Yes. In this last year 3 they've had several fuel issues.

4 MEMBER PETTI: Yes.

5 DR. JOHNSON: I have my own theory. I, 6 you know, I've been involved in chasing those. Back 7 in the '60s and '70s and '80s when you had some old 8 greasy guys making the fuel over in Virginia, never 9 had a problem whatsoever. Now we have a new 10 generation guys with new computer driven ways and 11 we've had all sorts of problems. So let's hear it for 12 the old guys.

13 But yes, the fuel in HIFR is right on the 14 edge. It is a water cell system. And if you bleed 15 off the worst thing that can happen, well, one of the 16 worst things that can happen, is that you have a leak.

17 And if you bleed off not more than a few gallons, 18 you'll go through a critical leak blocks and the core 19 will relocate. So, yes, it's a very high performance 20 machine.

21 So, I just have one slide on the safety 22 goals because I figured you guys were well aware of 23 it. You can say that there is a similarity between 24 this and these risk goals. You can say that.

25 It's the pretty, at least the original NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

42 1 1986 ones, are pretty thin in a way. But there is 2 qualitative and quantitative. Qualitative is the 3 rationale. No significant additional risk to the 4 life, to life or any individuals.

5 And in here they say that societal risk to 6 health should be comparable to less than risk of 7 generating electricity by viable comparable means and 8 should not be a significant addition to other societal 9 risks. So it's that second cause there that governs 10 that. The numbers here, if you will. But other than 11 that, the numbers are about the same.

12 Several places, I went back to the '86 13 Federal Reserve, Federal Register description. A 14 couple of places they make it clear that zero is the 15 number they want. No additional risks in the curve.

16 And it kind of made me feel like the 17 Delaney Clause all over again. I'm not sure if they 18 were just being politically correct in saying, in not 19 wanting to say that, you know, technology offers 20 benefits but also offers risks and we either accept 21 that or not. But it was a very strange reading at 22 almost 40 years later. A very strange way they worded 23 things.

24 One Commissioner, Asselstine, did have a 25 very interesting additional set of comments which I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

43 1 thought were spot on, is that basically we're missing 2 the chance here to talk about the relevant emphasis of 3 accident prevention versus accident mitigation and 4 however to balance it. I thought that was, given how 5 thin the other parts of the goals are in my opinion, 6 that was quite interesting.

7 So, looking at the challenges you guys 8 have going forward, you have new technologies, or the 9 rediscovery of old technologies. You have the 10 spectrum of reactor sizes, all sorts of reactor 11 pressures from essentially atmospheric to the ones 12 that we're looking at now. Larger numbers of reactors 13 at sites. Or in combinations. Mobile reactors.

14 I should say the additional point is 15 different environments. There is people considering 16 what it would take to, let's say, reintroduce reactors 17 into the marine business. Either providing 18 electricity, provide power for ships in port or 19 providing nearby creation of ammonia or hydrogen. Or 20 near offshore applications to even mobile reactors on 21 ships.

22 There is a huge number of barriers that 23 need to get solved before we go down that spectrum.

24 But there are people working on that sort of stuff.

25 One of the things is, our experience with NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

44 1 LWRs, which I think you all probably recognize is 2 creating a bias in terms of how we think about 3 reactors and risk, et cetera. You know, for example, 4 what would Level 1 mean for a molten fuel molten salt 5 reactor or a helium cooled reactor that has the TRISO 6 coded fuel.

7 Carl Fleming has tried to explain to me 8 several times that fuel hang together long after the 9 primary system has failed in an event.

10 And how should we treat co-located 11 technologies. And these are not things, like Walt was 12 saying, a nearby chemical plant or nearby industrial 13 facility, that these, my mind here is things that are 14 connected, if you will, to the reactor. The reactor's 15 purpose being, to provide district heating, 800 16 degrees sea steam for hydrogen production is just one.

17 And something that Dennis was saying, or 18 asking about, does a nuclear facility get credit for 19 replacing existing technologies. For example, should 20 we compare it to coal, diesel, diesel being what's 21 under in our ports, the answer is no. But they do 22 provide a nice referenced event, but they shouldn't 23 provide the basis for, for the analyses.

24 So, something I've been thinking about 25 quite a bit, actually, for several years now, are the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

45 1 security scenarios that are specified on existing 2 power plants out there. 10 CFR Part 73 type stuff.

3 There are similar issues in some of the newer 4 regulations that are being formulated out there.

5 And I understand that NRC is leaning 6 toward specifying security requirements that are 7 appropriate to the risk that the technology 8 represents. Whatever the hell that means. I'm not 9 sure what that really means.

10 But we've let the security issues at a 11 terrestrial power plant kind of go independent. It's 12 not something the PRA group, for example, really gets 13 their fingers into. But the NRC and San Clear 14 (phonetic), whoever comes and says, oh, here is your 15 new set of scenarios regard against, you know, show 16 that you can repel this sort of invasion, et cetera.

17 These are incredible expensive 18 requirements on a power plant. And to not be risk-19 informed in any way, shape or form. I know that the 20 one or two power plants where I understood what the 21 requirements were, I could tell you that if they were 22 to go to talk to the PRA people, A, they would have a 23 much more interesting set of targets to postulate.

24 But B, they operate in an independent world, if you 25 will.

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46 1 So my question for a long time has been, 2 why aren't those scenarios considered within the PRA 3 framework? After all, they start with initiating 4 event, they go through a process of successes and 5 failures and they end with an end state.

6 You can say it's a different beast, yes.

7 And if we understood uncertainty better we could 8 embrace that. It's a dynamic scenario. The 9 initiating event is affected by the current state of 10 affairs if you will. That's fine, we can handle that.

11 So I guess two questions. One, why aren't 12 those considered as a more integral part of the risk 13 scenario?

14 And two is, if we don't get our act 15 together and develop a coherent set of regulations and 16 approaches for these scenarios, these security 17 scenarios, we're going to preclude a fair number of 18 possible implications out there. Which might be the 19 appropriate thing. I happen to think not. But that's 20 just my question, is why are those considered 21 differently?

22 Somebody at a plant told me that something 23 like 15, ten to 15 percent of their OEM costs are 24 associated with their security forces. So, you know, 25 but there have been PRAs done, not from my mind, at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

47 1 least I have not done one for a nuclear plant, but 2 they have been don't for other facilities. They could 3 easily be done, in my opinion.

4 DR. BLEY: Dave?

5 DR. JOHNSON: So -- yes.

6 DR. BLEY: Dave? This is Dennis. Your 7 previous bullet, the top one of this page, I take it 8 that was your answer. And I'm a little curious about 9 that because I'm thinking back to another technology.

10 When I first moved to Southern California in 1979, 11 smog days were most of the year. You could hardly see 12 the mountains except for a few days around Christmas.

13 The Air Quality Management District, AQMD, 14 was invented and started doing these tradeoffs to get 15 credits for replacing air polluters with other more 16 modern technology. And in about 15 years, by the mid-17 '90s when I left, the situation was completely 18 reverse. There were only a few days a year where the 19 air was really bad and the rest of the time it was 20 good. They had great success.

21 They had a lot of opposition at first, you 22 shouldn't be doing tradeoffs, you should just be 23 getting rid of the bad actors. But that gave an 24 incentive and it was really successful. So I'm 25 curious about, why we shouldn't think about giving NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

48 1 credit --

2 DR. JOHNSON: Well I --

3 (Simultaneous speaking.)

4 DR. JOHNSON: Yes, that was my answer and 5 not the Committees or anything else. I was thinking 6 back on, we can make our technology, I think, in a 7 cost effective way, very attractive. And without 8 denigrating other technologies who are also on an 9 improvement path, if you will.

10 The marine industry is recognizing that 11 their a huge air polluter with what they burn at sea, 12 and in port, et cetera. But I don't want to, I don't 13 think it's necessary to compare diesel emissions to a 14 small nuclear plant, for example.

15 But yes, you could, I think referencing 16 the risks that are being replaced provides a great 17 framework, you know. But not basing on, not basing 18 the acceptability of your new technology on 19 replacement.

20 Let me --

21 DR. BLEY: Okay, thanks, I get where 22 you're coming from. I'm not sure I wholly agree with 23 it, but okay.

24 DR. JOHNSON: Oh, we've disagreed before 25 some. And I'm okay with it.

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49 1 (Laughter.)

2 CHAIR BIER: So, Dave, are you done with 3 your prepared remarks?

4 DR. JOHNSON: No, I have two more if you 5 would.

6 CHAIR BIER: Okay. So go ahead.

7 DR. JOHNSON: The last set of bullets on 8 this page is one that's designed to make everybody on 9 both sides of the equation angry at me.

10 So we had an advantage looking at it in 11 hindsight that very many people were fluent in PRA 12 back in the '77,'80 timeframe. Now everybody thinks 13 they're gone, so. But I'm just stunned by the fact 14 that, when I hear some industry folks talk, that they 15 seem to be reluctant to embrace PRA when I think it 16 would be one of the best tools they have in their tool 17 box for design.

18 And on the other hand, you know, when I 19 look at my cursory reading, I should say, of Option B 20 of the Part 53, it sort of sounds like PRA, but it's 21 not. So I'm not sure if I don't -- if I no longer 22 understand what PRA is, or not very many people seem 23 to.

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50 1 either, but it was an old Godiva class reactor. I 2 think the PRA was 50 pages. So don't tell me I've got 3 a simple plant, and simple design, and I'm not going 4 to spend mega bucks doing a PRA. You know, you would 5 be silly to --

6 MEMBER PETTI: Dave, I actually do think, 7 I agree with you here. The people that are saying 8 they don't -- there's a lot of people who don't want 9 to do a PRA, because they think it will cost them a 10 lot of money, because light water reactor PRAs cost a 11 lot of money. These newer systems are smaller, 12 they're simpler. I agree with you. The PRA should be 13 simpler in principle.

14 DR. JOHNSON: Oh, absolutely.

15 MEMBER PETTI: And that just isn't getting 16 out there to certain parts of the community.

17 DR. JOHNSON: Yeah. So I'm stunned that 18 both the designers, not all of them but some of them, 19 some of the ones that I'm working with, theoretically 20 that they haven't seen it. But anyway, it just stuns 21 me.

22 And then this Part B, Topic B of Part 53, 23 I'm not sure what the hell that is quite frankly. So 24 anyway --

25 MEMBER PETTI: Yeah. If we don't clarify NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

51 1 a path to licensing, we can have the ability to 2 manufacture these things in a cost effective way. And 3 they could, on paper, have a great risk signature and 4 be all, you know, proven to be economical. But if we 5 remain fuzzy on the licensing rules, these things will 6 never see light of day. Anyway --

7 DR. JOHNSON: One last slide, and it's 8 things we've already covered that I just tried to 9 gather out the lighter task that is harder than my 10 task. Reactor designs are very -- in hindsight we 11 ignored Fort St. Vrain. It was around, we just, I 12 can't remember any discussion once I thought about it.

13 And we talked about these other things, about the 14 different types of fuels, et cetera.

15 I'm done, Vicki.

16 CHAIR BIER: Okay. So we are more or less 17 at perfect timing for any public comments at this 18 time. And, yes, Edwin, thank you.

19 DR. LYMAN: Hello, this is Edwin Lyman 20 from the Union of Concerned Scientists. Can you hear 21 me?

22 CHAIR JOHNSON: Yes.

23 DR. LYMAN: Thanks. So I'd like to say I 24 think the ACRS is, this is a very valuable activity, 25 and we're very glad that you are taking this on.

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52 1 Because I think it's critical to understand both the 2 origins of the safety goals as well as where they 3 should go.

4 I'd like to make a couple of comments 5 regarding our views on the use of the current safety 6 goals in Part 53. What I haven't heard here is one 7 issue that concerns me. And that's the safety goals, 8 at least combined with current understanding of the 9 relationship between large releases and total number 10 of cancer deaths, really corresponds to core damage 11 frequencies on the order of one times ten to the minus 12 to the third, one times ten to the minus three.

13 And that's obviously considerably lower 14 than what the fleet average CDX is considered these 15 days. So the safety goals are no longer, they don't 16 represent a standard of safety that's anywhere near 17 what the current fleet is supposed to represent. And 18 therefore, they set too low a bar for establishing 19 fundamental safety limits going forward.

20 And this isn't an issue of whether the NRC 21 should ratchet up safety goals for new reactors or 22 not, this is simply recognizing what the current 23 situation is and the safety goals in relation to them.

24 So if you keep this, you know, the safety goal limit 25 as, you know, this very low bar, it's just not very NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

53 1 useful in establishing important safety goals for the 2 future. So I think that has to be recognized.

3 Another issue, another deficiency with the 4 safety goals is this averaging over, you know, the 5 general U.S. population, you know, general just 6 averaging over individuals in specific reactor sites.

7 These types of averages wash out the kind of 8 disproportionate impacts of a nuclear accident and how 9 it could affect vulnerable populations differently.

10 And it's also -- so in addition to the 11 heterogeneity of, you know, the U.S. population in so 12 many different ways, also the use of cancer fatalities 13 instead of cancer incidents doesn't acknowledge or 14 it's not sensitive to the disparities in care that 15 lead to different cancer mortality risks for different 16 populations compared to incidents.

17 And so continuity is -- cancer mortality 18 in averaging is not recognizing the important 19 disparities that, I think, the NRC, as well as the 20 whole of the federal government, are trying to 21 address now for the link into their varying 22 environmental justice initiatives.

23 So I think those are some of the 24 highlights in addition to, of course, the lack of the 25 societal safety goal which, I think, the committee NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

54 1 understands very well and should definitely be a part 2 of any future regulatory regime that's incorporating 3 safety goals. Because that's a gap which should be 4 apparent to anyone. Those are my remarks. Thank you.

5 CHAIR BIER: Thank you very much. Any 6 other public remarks? If you are on Teams, you can 7 raise your hand to be recognized. If not, feel free to 8 just unmute yourself and speak up.

9 Dave, are you --

10 DR. JOHNSON: I was muted, sorry. Let me 11 say, I think Ed's got some great points. And I wasn't 12 trying to have a comprehensive view of where we should 13 go in the future or all of the sins we've had in the 14 past. Yet somewhere along the line we, the industry 15 and the NRC, you know, moved away from Level 3 16 studies. And I think some of those issues would be 17 more visible if we had more Level 3 studies and looked 18 at some of the issues you talked about.

19 There's a number of things you'll run 20 across when you're going back through the NRC 21 presentations and documents on some metrics. You 22 know, for example, in several places I have found 23 words that said that core damage frequency is a 24 surrogate for society cancer risk. And that's, of 25 course, nonsense. I mean, it might be necessary, but NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

55 1 it's not sufficient. We're fooling ourselves if we 2 think that that's a decent surrogate measure.

3 So I think, when you think this problem 4 through and you're in the group, you have a chance of 5 doing a much better job than when we did back then.

6 We're older and wiser, and it's a more complex 7 landscape. So anyway, that's my two cents.

8 CHAIR BIER: Thank you. Again, opening up 9 for any other public comments. We have another 30 10 seconds or so.

11 Okay. Hearing none, I think we can go 12 back to general committee discussion at this time.

13 And I will just add that, if anybody is listening in, 14 feel free to send your remarks to Hossein after the 15 meeting is done.

16 Walt?

17 MEMBER KIRCHNER: Well, thank you very 18 much, Dave, for your presentation, very informative.

19 I previously had highlighted the metric that was used 20 in one of your slides which were essentially, how do 21 I phrase this, instead of, it was like a surrogate for 22 a reactor year, assuming that the reactor was 23 nominally 1,000 megawatt class.

24 So it raises the question going forward 25 about reactor year, as per year, reactor years as a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

56 1 metric if we proliferate a lot of small reactors over 2 the countryside. I don't mean that as a pejorative 3 statement, but it certainly -- how do you actually 4 then measure the impact? Do you do it on an 5 individual reactor or some cumulative effect, societal 6 effect. So I'm not looking for an answer, just make 7 that an observation.

8 The second one, maybe I would pose this 9 one more as a question. How, as we go forward and if 10 we base the licensing approach more and more on a PRA, 11 how do we go back and address the QA issue that you 12 talked about of, well, now we currently have standards 13 and reg guides for this purpose. And then we use peer 14 review. But it's not necessarily the equivalent of 15 the deterministic world in NQA 1.

16 So do you have any feelings on that? How 17 do we go forward? Because one of the concerns would 18 be with, especially new designs, what are the unknowns 19 out there? And how do we thoroughly search the space 20 to hopefully make sure we're comprehensive in covering 21 the landscape of potential risk to the public from a 22 new concept?

23 And you have a good example. If you're 24 stripping fission products actively, then you're 25 creating, you know, a source term, so to speak, that's NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

57 1 potentially at risk of, or vulnerable is a better word 2 to use here, of release. Any thoughts on what we 3 could do? Or do you think the current process for 4 peer review meets the mark in terms of QA of the PRA?

5 DR. JOHNSON: Vicki, can I speak --

6 CHAIR BIER: Oh, yes, you should feel free 7 to reply.

8 DR. JOHNSON: So I have the ability to 9 alienate any number of people, ha. I think the QA for 10 the PRA as specified, or as followed in the standards, 11 is excellent. The weakest point in that process by 12 far is the peer review requirement. It's kind of done 13 quickly at the end.

14 It's highly, and this is my opinion, it's 15 highly dependent on the team that you put together.

16 I can show you -- maybe that's too strong a statement, 17 but I'm aware of one element of one PRA that was, and 18 appropriately exactly the same set of words from a 19 different PRA. One got a best practice, and one got, 20 you know, unacceptable.

21 You know, there was a time when PRAs were 22 sent to a national lab, and they spent gobs of money, 23 but you came back with an SER, right, that had some 24 value to it.

25 I think if we were to utilize PRA more, we NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

58 1 would need to go back and think about that peer review 2 process and current resolution process coming out of 3 that. I think that's the, probably the only weak 4 point there.

5 The other point to mention is that these 6 new technologies are going to be exploring new 7 physics, right, with different materials and things 8 like that. That has to be represented in the studies.

9 And that can be in terms of performance, and safety, 10 et cetera.

11 And I guess the last point I wanted to 12 make is you said something about PRA-based licensing.

13 I think that's the last thing that we're asking for.

14 Because exactly, there are things that PRA is not 15 appropriate or doesn't handle well. And that's the 16 whole idea behind the performance based ideas is there 17 will be a set of deterministic criteria blended with 18 risk requirements and risk measurements. So I'm 19 optimistic.

20 But I think we do need to change how we do 21 the QA part of the, the peer review part of the PRA 22 and get people to really understand what PRA is. I'm 23 pessimistic that somehow that's been lost.

24 CHAIR BIER: Dave, one minor point of 25 order. I think we are looking at your security cam NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

59 1 footage. So you might want to stop sharing your 2 screen or something. Looks attractive, but not 3 necessarily what you want to be sharing.

4 MEMBER KIRCHNER: It's my yard.

5 CHAIR BIER: Yeah. Okay.

6 (Simultaneous speaking.)

7 CHAIR BIER: Let me see if I -- maybe I'll 8 try to undo it.

9 (Simultaneous speaking.)

10 CHAIR BIER: Thomas, is that something you 11 can do on your end to take down his screen sharing or 12 do something?

13 PARTICIPANT: Hold on a second. Stop 14 sharing.

15 CHAIR BIER: Awesome, excellent. Much 16 better. Thank you.

17 Vesna, you can go ahead now.

18 MEMBER DIMITRIJEVIC: All right, as long 19 as I find my microphone. Yeah. Hi, David. So I can 20 be very vocal against what they're proposing currently 21 in terms of part 53 in the PRA-based approach.

22 And what they're proposing to use is a 23 realistic safety goal which is based on the latter and 24 the early fatalities. So basically what they're 25 proposing to use is a goal, the individual within ten NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

60 1 months, or client, is exposed to loss and fatality 2 base less than two to the minus six period.

3 And I'm very vocal against this. There is 4 a couple things why I am very vocal, and you just said 5 this in one of your last sentences. And what you said 6 is to the CDF, is using CDF as substitute of the goal 7 for the counter fatality is really, you know, 8 ludicrous in my opinion. And I have a feeling you 9 have the same opinion.

10 So I have often expressed this. I've 11 wrote additional opinion, but I cannot find a really 12 good argument, because the main argument NRC has 13 against that is that served them well, you know, 14 through the years. So my argument will soon develop, 15 but in the PRA is subsidiary goal, CDF and Murph but 16 not the cancer goals and not only fatality goals.

17 So in my opinion, you know, the 18 qualitative goals are, you know, not to present 19 additionally to the society. That took time. I 20 thought that we have enough problem with going one 21 percent, you know, that that's enough, a significant 22 addition.

23 So this project that they are promoting is 24 also, you know, okay to say it's a goal. But 25 transferring, having the goal for the new plant to be NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

61 1 built to prove that a loss in fatality risk or cancer 2 risk is less than three minus six per year, that's 3 total nonsense in my opinion. It's nonsense mostly 4 because when we say two minus six, it implies that we 5 know something about that.

6 So that could be it's not three minus six, 7 it's not 40 minus six, it's two minus six. And that 8 will imply that we totally understand connection in 9 this case. And I'm just going stay on core damage 10 frequency, so it's totally agreeable in discussion as 11 to the early fatalities.

12 So that means that we totally understand 13 connection between, you know, core damage frequency 14 and cancer, and that we, you know, it neglects all the 15 uncertainties which are totally widespread everywhere, 16 you know. There is uncertainties in Level 1, there is 17 the higher certainties in Level 2. And when we come 18 to the Level 3 uncertainties, in my opinion, are 19 really high.

20 And also there is, you know, when they 21 completed this PRA Level 3, the project in NRC that 22 have shown in the Level 3 which they have done, that 23 actually connections between the core damage 24 frequencies and the, you know, cancer risk, or the 25 early fatalities is much smaller than they would NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

62 1 estimate based on the early PRA. So currently 2 probably core damage frequency of ten to minus two 3 would satisfy this goal for cancer.

4 So my objection is totally to remove the 5 cancer and the early fatalities as probabilistic goal.

6 But however, I don't really have a good idea of what 7 could replace that. And I was thinking we can really 8 work with whoever comes in the first application with 9 the people trying to estimate risk connected.

10 If there is no core damage frequency, and 11 there is no large release frequency, if there is a 12 core damage frequency, large release frequency, stay 13 on the current goal.

14 If there is some, then let's work together 15 to develop some new representation of the societal 16 risk. So basically what I wanted to say, my main 17 objection is to use the cancer and early fatalities as 18 probabilistic safety goal in this moment. So I don't 19 know what your opinion about something like this would 20 be.

21 DR. JOHNSON: So I guess my first reaction 22 is go back to the Level 3 PRAs that were done in the, 23 you know, late '70s or early '80s. I think they would 24 all say that there's not a strong connection between 25 core damage frequency and offsite health effects. The NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

63 1 scenarios that contribute to offsite health effects 2 tend to be smaller in frequency.

3 But I have to say that, you know, NRC's 4 reason for existing is to protect the public health 5 and safety. So I think they have to have public 6 health and safety measures as part of their goals, et 7 cetera. And I don't, you know, I agree with you that 8 the scenarios are few and far between. But I guess, 9 where do I start?

10 It has frustrated me that, with the 11 utilities I've work with, there's been a couple who 12 understand that the real scenarios that they need to 13 guard against aren't limited to the ones that result 14 in maybe core damage frequency at all.

15 But, you know, there are scenarios that 16 would result in their loss of plant with the fuels 17 intact. And, you know, they spent money to avoid, you 18 know, that sort of thing. So I'd be happy if 19 utilities adopted a holistic view of safety. I'd be 20 happy if the NRC adopted a view that focused on public 21 health and safety.

22 I still don't understand why we stopped 23 doing Level 3 studies. The one NRC did, it doesn't 24 have to be as complicated as what they did. So I 25 don't know. I'm frustrated. What can I say?

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64 1 But I guess I would like to leave with one 2 question, is what is it they share as, what's their 3 charter, if you will? What's their goal for providing 4 input on a quantitative study, quantitative health 5 study, or quantitative risk goals, if you will?

6 Back in 1980, it was to try to get NRC to 7 think about if framework for how they do business, not 8 particularly establishing rules and goals for 9 individual plants. That would fall out of the 10 analysis. But it was to try get NRC to quit being 11 kind of ad hoc, if you will.

12 MEMBER DIMITRIJEVIC: Well, you know that 13 everything started, you know, with the WASH-1400 core 14 damage frequency and large release frequency. And 15 they were --

16 DR. JOHNSON: Well, I --

17 (Simultaneous speaking.)

18 DR. JOHNSON: -- release frequency. They 19 had release categories. My release frequency --

20 MEMBER DIMITRIJEVIC: Right.

21 DR. JOHNSON: -- is something that --

22 (Simultaneous speaking.)

23 DR. JOHNSON: -- essentially was admitted 24 later that has really muddied the water. Go ahead, 25 excuse me.

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65 1 MEMBER DIMITRIJEVIC: Well, then in the 2 time which you just described working with, you know, 3 existing Zion and the point -- whatever existing PRAs 4 at that time, it was proved that this core damage 5 frequency, so ten to minus four and whatever, large 6 release, or ten to minus five, really don't introduce 7 large additional cancer risk and prompt fatality risk 8 to the public.

9 So it started from the CPS and the 10 releases. And then we went to prove that it didn't 11 increase risk to the public. But now that risk to the 12 public drives, you know, it's a sort of, now it's a 13 sort of back to that chicken and egg. Now the risk 14 for public becomes the prompt driver. And there are 15 so many implicities associated with that.

16 So when I was thinking working with 17 whoever is the first one to pass who doesn't have a 18 core damage frequency, and it could be different 19 releases, it could be different damage to the core.

20 It focused on different measure which will be 21 presented and still guarantees there is no increase in 22 the risk to the public. I mean, you know, I'm not 23 sure. I think we have to wait instead of presenting 24 this cancer and early fatalities risk to --

25 DR. JOHNSON: I hear what you're saying.

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66 1 But, you know, just the window, WASH-1400 also 2 included land contamination. It's just that somewhere 3 along the long we stopped talking about that. And 4 that's probably the biggest signature that the public 5 would see.

6 MEMBER DIMITRIJEVIC: What was it did you 7 say? I didn't hear you well.

8 DR. JOHNSON: Oh, WASH-1400 also included 9 a measure of land contamination.

10 MEMBER DIMITRIJEVIC: Yeah, right. No.

11 You know, when you were building all of these in the 12 '80s, we didn't have a Three Mile Island, we didn't 13 have a Chernobyl, and we didn't have a Fukushima.

14 We can look back now and learn much more, 15 you know, what are really consequences of the nuclear 16 accidents and how we can measure them instead of, you 17 know, trying to state for something which was 18 developed 40 years ago. So, I mean, that's my, you 19 know, but thanks for these questions.

20 CHAIR BIER: Yeah. Joy?

21 MEMBER REMPE: I'd like to respond to 22 Dave's question about what our charter is and our 23 task. Because I even see in some of Dave's slides 24 that question could easily get -- the answer might be 25 incorrect.

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67 1 And what you said at the very beginning of 2 this meeting is correct, Vicki, that we have a working 3 group, and we are exploring what might be improved.

4 Maybe it's just an implementation of the safety goals, 5 but we do not have a charter to investigate this task.

6 We saw there were difficulties when we 7 were reviewing Part 53. And you mentioned in your 8 presentation, Dave, how much more difficult it is with 9 some of these reactors that have molten fuel, for 10 example. And we're just gathering information, as 11 Vicki said, at this time.

12 And so again, when we have a working group 13 in ACRS, it's to help us look at something that we 14 think might be important to safety. But we don't have 15 a clearly defined charter at this time. Does that 16 help with responding to your question, Dave?

17 DR. JOHNSON: Yes.

18 MEMBER REMPE: And I'm making a big point 19 of this because the public is also listening to it.

20 CHAIR BIER: Sure, yeah.

21 MEMBER REMPE: And I want to make sure 22 that no one walks away from this meeting with an 23 incorrect assumption, if possible --

24 (Simultaneous speaking.)

25 CHAIR BIER: Yes. I mean, first of all, NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

68 1 we have not been tasked by the Commission and the 2 staff to look at safety goals, and we have not 3 determined that we are going to propose any 4 modifications or whatever.

5 But it did come up as part of our Part 53 6 review, which is supposed to be technologically 7 inclusive regulation framework, that some of these 8 technologies would not fit comfortably into the 9 established safety goal framework. So we wanted to 10 just think through the implications of that.

11 So I have a few questions for Dave, but I 12 should wait and see if any other committee members 13 have additional questions right now.

14 Okay, I will charge ahead then. First of 15 all, the most closely tied in a way to the Part 53 16 analysis, as you indicated Part 53 allows multiple 17 different frameworks including possibly bounding 18 analysis that a plant might come in without a PRA and 19 just say, hey, we have this calculation that says our 20 risk is less than such and such.

21 So your argument that, well, it should be 22 possible to do simplified PRA for simplified reactor 23 designs, even if we think that's a good thing, that 24 should be assailed at least in terms of what's 25 permissible under Part 53 that somebody would not need NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

69 1 to do that.

2 And do you have any thoughts about what 3 you might recommend or consider if plants do come in 4 with a bounding analysis? If their bounding analysis 5 is satisfactory, does that mean they already might 6 have safety goals, or is there some other safety goal 7 type check that could be imposed?

8 DR. JOHNSON: I don't know if that's an 9 answerable question. My reaction is that, you know, 10 one lesson that we should have learned over and over 11 again, and we don't seem to, is whenever we try to 12 simplify PRA, or bounding analysis, et cetera, the day 13 will come when we realize that that was an error.

14 CHAIR BIER: Ha, ha, ha.

15 DR. JOHNSON: So if the ship has sailed, 16 the ship has sailed.

17 CHAIR BIER: Yeah.

18 DR. JOHNSON: If they come in with a 19 bounding analysis, I would put my hat on and try to 20 show why it's not bounding. That's a tough thing to 21 do, right.

22 CHAIR BIER: Yeah.

23 DR. JOHNSON: You know, like I said, a 24 simple plant could have an elegantly beautiful but 25 simple PRA, and you'd embrace it.

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70 1 CHAIR BIER: Okay. Two other points, one 2 which isn't really a question but really just an 3 observation that I think you really helped clarify, I 4 have commented in the past that the comparison that's 5 in the goals with baseload coal plants may not apply 6 very much anymore if the majority of baseload power in 7 many parts of the country is no longer coal.

8 But you raised this other point that 9 everything has gotten safer --

10 DR. JOHNSON: Right.

11 CHAIR BIER: -- since then. Coal plants 12 are safer, because they have more scrubbers. Cars are 13 safer, because we have anti-lock braking systems and 14 all kinds of other things.

15 And so, you know, maybe the era where we 16 were replacing dirty coal plants with cleaner, nuclear 17 plants, that kind of comparison might have made sense, 18 but in a world where everything is already safer, 19 maybe we don't need to be safer than everything else 20 that's out there, kind of.

21 DR. JOHNSON: I don't want to, yeah, move 22 away from the idea of comparison directly. I mean, 23 you can even talk about green technologies.

24 CHAIR BIER: Yes.

25 DR. JOHNSON: Some of them look nice on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

71 1 the future and nice in our backyard but, you know, 2 there's a very coherent argument that says what we've 3 done is we've exported our pollution.

4 CHAIR BIER: Right. If you take a 5 complete life cycle view, they're not all that green 6 necessarily.

7 DR. JOHNSON: So I wouldn't jump on that 8 boat.

9 CHAIR BIER: Okay.

10 (Simultaneous speaking.)

11 CHAIR BIER: Right. The one other comment 12 I wanted to make, that ties a little bit to the point 13 you raised about security risk and physical sight 14 security, my understanding is that initially part of 15 the reason that was taken out of PRA, or not included 16 in PRA is maybe a better a way of putting it, is just 17 that it required different expertise and different 18 precautions. And in particular, you might require a 19 security clearance to --

20 DR. JOHNSON: Right.

21 CHAIR BIER: -- do the work or access the 22 results so it didn't fit in a public document like a 23 PRA.

24 But one person I've talked to recently 25 raised an interesting point that if you are looking at NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

72 1 plants where the inventory and the source term are 2 small, and therefore the risk is extremely small, 3 sabotage and, you know, physical security might be the 4 single biggest source of risk.

5 You know, yesterday we saw an analysis 6 that had extremely low risk numbers for technology.

7 And, you know, the probability of a successful 8 sabotage event might be higher than the risk numbers 9 they cited using their traditional PRA approach.

10 DR. JOHNSON: So the security questions, 11 your last question is probably the old argument for 12 keeping the security scenarios closely held.

13 CHAIR BIER: Yes.

14 DR. JOHNSON: But, you know, since 9/11 we 15 no longer make FSARs and PRAs that are --

16 (Simultaneous speaking.)

17 DR. JOHNSON: -- publicly. Because, you 18 know, one of them gave you the layout drawings, and 19 the other one gave you the --

20 (Simultaneous speaking.)

21 CHAIR BIER: Yeah.

22 DR. JOHNSON: -- summation of effects.

23 But there is a new reg that I've used, and I'll try to 24 dig it up. The text itself is kind of worthless, but 25 there is an appendix that helps you characterize NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

73 1 external threats, if you will, in a spectrum that's a 2 function of what their goals are, what their technical 3 expertise is, what tools they have available, what 4 price they are willing to pay.

5 And it goes from petty theft type things, 6 to news of shutdowns of the plant, all the way up to 7 the core damage frequency. So I've used that spectrum 8 to look at security risk stuff.

9 And with a different hat, I've been 10 looking at the barriers to reintroducing nuclear to 11 commercial shipping, et cetera, et cetera. And at 12 least we're on that now. My thinking is we can make 13 the reactor -- very robust to external bad guys, et 14 cetera, et cetera.

15 But the success from the bad guys' point 16 of view may not be dispersal of power. It might be 17 sinking that ship that has a big N on the side of it.

18 I mean, you need to think broadly of what success and 19 failures are in these cases.

20 CHAIR BIER: Yes.

21 DR. JOHNSON: But I honestly think that we 22 need to step back and look at this whole security 23 question from a holistic point of view and not isolate 24 it the way it is now. But I should say, I think I'm 25 the only one saying that.

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74 1 (Laughter.)

2 CHAIR BIER: Well, I think I'm --

3 MR. MEIER: I don't think so, Dave. I've 4 heard other people --

5 MEMBER KIRCHNER: Yeah, I think you're 6 right on, Dave.

7 MR. MEIER: -- express that exact comment.

8 Yeah, I know people working actively in this area, 9 they kind of push back.

10 MEMBER KIRCHNER: Yeah. So far, Dave --

11 CHAIR BIER: At a minimum --

12 MEMBER KIRCHNER: -- it doesn't serve the 13 public's good.

14 CHAIR BIER: Yeah.

15 MEMBER KIRCHNER: On this particular issue 16 as impacts safety and potential risk. So I think 17 you're right on, Dave. Yeah.

18 CHAIR BIER: And at a minimum, you know, 19 our whole approach in this current working group is to 20 say, hey, maybe we don't need to be bound by the 21 assumptions of several decades ago we could take a new 22 look, and see if we have more sensible assumptions.

23 And so security might be one area where we may want to 24 do that.

25 So any other questions or comments for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1716 14th STREET, N.W., SUITE 200 (202) 234-4433 WASHINGTON, D.C. 20009-4309 www.nealrgross.com

75 1 Dave?

2 Well, this was extremely interesting. I 3 think it gave us a lot of good things to think about.

4 And I want to thank everyone also for their comment.

5 And, Dave, I will be getting back to you 6 probably in the next few days just to help track down 7 a couple of references that we may want to add to our 8 database to be informed by.

9 DR. JOHNSON: Okay. I have a limited 10 number that I kept during the --

11 CHAIR BIER: Yeah.

12 DR. JOHNSON: --- and brought in.

13 CHAIR BIER: Well, that's okay. I 14 understand it's a long time ago. You probably purged 15 a lot of paper. So, you know, and some -- Hossein and 16 the staff may also be able to track down at the NRC.

17 But for instance, the Bowen reference that you 18 mentioned seems to be cited but not easily available 19 online from what I can tell. So, you know, we may 20 need some effort to track that down through a library 21 or something.

22 DR. JOHNSON: And then Paul Slovak has got 23 a wide collection of, you know, publications he may 24 have at his plant.

25 CHAIR BIER: Yeah, for sure. Okay.

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76 1 DR. JOHNSON: All right. I'll go eat 2 lunch now.

3 CHAIR BIER: Good, fantastic. Well, thank 4 you very much for joining us. And I guess I will see 5 everybody in a couple of weeks at full committee.

6 MEMBER REMPE: Thanks, Vicki and Dave.

7 CHAIR BIER: Sure thing. Thank you.

8 (Whereupon, the above-entitled matter went 9 off the record at 2:51 p.m.)

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A Perspective on Nuclear Quantitative Safety Goals David H. Johnson, ScD Las Cruces, New Mexico

Presentation Outline

  • Introduction
  • 1980 ACRS Safety Goals
  • Safety Goals developed for 1998 HIFAR PSA
  • NRC QROs
  • Moving forward in an era of SMRs and Microreactors

1980 ACRS Quantitative Safety Goals

  • Historical Environment
  • Limited number of nuclear PRAs
  • 1975 WASH 1400 Final Report
  • 1978 Oyster Creek PSA
  • 1979-1981 Zion and Indian Point PSAs
  • Attitude at NRC regarding PRA mixed
  • TMI was a recent event
  • Inconsistent Federal Guidelines
  • Radiation exposure limits
  • Delaney Clause of Federal Food, Drug and Cosmetic Act (Food Additives Amendment of 1958)

ACRS Quantitative Safety Goals Published as NUREG-0739 NUREG-0739 An Approach to Quantitative Safety Goals for Nuclear Power Plants Manuscript Completed: October 1980 Date Published: October 1980 Advisory Committae on Reactor Safeguards U.S. Nuclear Regulatory Commission Key contributors: M. Griesmeyer, D. Johnson, W. Kastenberg, D. Okrent

ACRS Perspective on Importance of Safety Goals NRC Rules and Regulations and in NRC Staff documents dealing with safety such as Regulatory Guides and Branch Technical Positions(represent) basically a risk reduction philosophy without fully articulated safety goals.

NUREG-0737, Page 51 Safety goals key to providing NRC with a coherent framework for effective regulation Goals were not to be considered absolute or viewed in isolation - there may be excellent reasons to allow operation above goal

Form of the Quantitative Decision Rules

  • Limits on the frequency of certain hazards states within the reactor
  • Limits on the risk to an individual of early death, or delayed death due to cancer
  • Limits on the overall societal risk of early or delayed death (includes a small measure of risk aversion)
  • Includes Averted Negative Economic Impact/Loss of Resources Assumed that controlling early deaths and latent cancer deaths would control other effects as well

References

  • Adams and Stone: 1967 risk to an individual should be governing factor; specific value responsibility of appropriate government body; limit should be smaller than the demographic variation in the UK of individuals risk of dying from other hazard sources; something on the order of 10-5.
  • Farmer: 1967 0.01 premature deaths per ry. In addition, a frequency-consequence due to I131. Included risk adversion.
  • Bowen: 1975 Risks should be smaller than benefits gained by technology
  • The Committee benefited from meetings with Bill Lowrance and Paul Slavic

Different Metrics Were Explored One of my (rejected) ideas.

Why do we do PRA?

1. Arrive at a rank ordered list of scenarios that contribute to specific damage states
2. Identify and understand sources of uncertainty To approach the second goal: establish goal/limits on 50th and 85th, rank order contributors The best cdf curve we had access to was an early draft of Zion PSA. 50th percentile was 1 x 10-4; 85th percentile was 5 x 10-4. (You will see these numbers again soon.)

Goals and Upper Limits for Hazard States Upper Nonacceptance Significant core Goal: Less than Goal: Less than 3 Limit: Less than 1 Limit; a Discretionary damage (10% 1/100 per reactor x 10-4 per ry x 10-3 per ry Range ; and a Goal Nobles leaking lifetime into primary coolant)

Large Scale Fuel Goal: Less than Goal: Less than 1 Limit: Less than 5 Numbers look Damage 1/300 per reactor x 10-4 per ry x 10-4 per ry familiar?

lifetime Large Scale Goal: Small, Goal: Less than Limit: Less than Release from given Large Scale 0.01 per LSFD 0.1 per LSFD Compliance with Containment Fuel Damage Upper Limit Required (greater than 10% for Extended I and 90% Nobles) Operation

Individual Risks (Most Exposed Individual)

Likelihood of Goal: less than 5 x Limit: less than 2.5 Goal: Mean Limit: Mean cancer death due 10-6 per site year x 10-5 per site year conditional conditional to all reactors at likelihood given likelihood given site over LSFD: less than LSFD: less than individuals 0.01 0.05 lifetime: less than Background cancer death risk 0.15 - 0.20 0.0005 Likelihood of early Goal: less than 1 x Limit: less than 5 x Goal: Mean Limit: Mean death due to 10-6 per site year 10-6 per site year conditional conditional reactor accident likelihood given likelihood given over individuals LSFD: less than LSFD: less than lifetime: less than 0.002 0.01 0.0001 In the US, 10-14 year-old girls have lowest death rate 10-4

Societal Risks Expected value cancer Goal: less than 2 per Limit: less than 10 per deaths- normal 1010 kwh (approximately 1010 kwh operation and accidents 1200 MWe at full capacity)

Expected value early Goal: less than 0.4 per Limit: less than 2 per deaths due to accidents 1010 kwh 1010 kwh (alpha=1.2)

Estimates available in 1980 suggest similar size coal plant results in 10-200 excess delayed deaths

Additional Requirements

  • Special attention should be given to QA of PRA
  • Full and explicit identification of assumptions and limitations
  • Peer review required
  • Additional suggestion: Establish a Risk Certification Panel with statutory authority

Hindsight

  • Only Individual risk of cancer death explicitly considered all reactors at a given site
  • While Zion PSA was full scope, level 3; role of shutdown risk not appreciated
  • Co-located technologies not considered
  • Whereas Coal risk provided a benchmark for some measures, nuclear replacing existing technology not considered
  • I still believe we missed the chance to provide appropriate attention to uncertainty

High Flux Australian Reactor (HIFAR)

  • DIDO Class research reactor: neutron diffraction, transmutation of silicon and medical and industrial isotope production
  • 10 MW-th, heavy water cooled, moderated; graphite reflected
  • Operational 1960 to 2007
  • PSA (and companion probabilistic remaining life study): 1998

References

  • OECD: 1994 fuel damage 10-4 to 10-5
  • Netherlands: 10-4 for existing plants, 10-5 for new plants
  • In the US, as of November 1995, 14 of 77 plants reported a cdf greater than the informal limit 10-4.
  • HIFR reactor at ORNL: 3 x 10-4 cdf
  • Difficulty in comparing above due to varying scope, methods

References:

New South Wales Department of Planning

  • Maximum incremental annual risk of premature death
  • Hospitals, schools, child care facilities, old age housing 0.5x10-6
  • Residential developments and areas of continuous occupancy 1.0x10-6
  • Commercial developments 5.0x10-6
  • Sporting complexes and active open space areas 10x10-6
  • Industrial sites 50x10-6 Key Point: Australia had a framework relating activities to risk

Relevant Factoids Objectives versus Limits Relatively modest power: 10 MWth Low primary system pressure Limited supporting analyses for mechanical damage Limited supporting analyses for recriticality

  • Primary Objectives: fuel overheating Limited analyses for transport of
  • Thermal power 10MW vs 2000-3000MW
  • HIFAR slightly above atmospheric vs75-160 bar
  • Fuel in core or number 1 storage block with containment failure due to bypass, failure to isolate or overpressure: 5x10-5
  • Secondary Objectives:
  • Mechanical damage to one or more elements (with and without containment)
  • Fuel element mechanical damage resulting in overheating or criticality
  • Loss of cooling to stored fuel
  • Release of tritium without fuel damage (with and without containment)

Key Point: Objectives were specified on fuel damage frequency and unanalyzed events

NRC Safety Goals

  • Qualitative
  • Individual members of public bear no significant additional risk to life and health
  • Societal risks to life and health should be comparable to or less than the risks of generating electricity by viable comparable means AND should not be a significant addition to other societal risks
  • Quantitative
  • Individul risk of prompt fatalities should not exceed one-tenth of one percent of the sum of prompt fatality from other accidents to which public is generally exposed
  • In are near a nuclear plant, cancer risk due to plant operation should not exceed one-tenth of one percent of cancer fatalities from all other causes
  • Additional views of Commissioner Asselstine: Commission should have developed policy on the relative emphasis of accident prevention and accident mitigation (to provide balance between the two)

Moving Forward - Challenges

  • Spectrum on new technologies (or rediscovery of old technologies) on the horizon
  • Spectrum of reactor sizes; operating pressures
  • Multiple reactors at sites
  • Mobile reactors
  • Our experience with LWRs has created bias (e.g., what does Level 1 mean for MSR or He cooled reactor?)
  • How to treat co-located technology?
  • Beneficial
  • Harmful

More Considerations

  • Does nuclear facility get credit for replacing existing technology?
  • Coal plant replacement
  • Diesel
  • ANSWER: NO, but risk from replaced technology provides a reference point
  • Why are Industry and NRC avoiding use of PRA?
  • Some in industry reluctant to use PRA in design, it seems
  • A simple design should imply a simple PRA (e.g. HPRR PRA was some 50 pages)
  • Option B of part 53 seems to specify unphysical scenarios (maximum accident not possible EVERY year)

1980 vs 2023 Your Task in More Challenging 1980 2023 Reactor Designs Only PWRs and BWRs (we ignored Ft St Vrain) Diverse Designs Power Levels large Diverse, many quite small Siting Fixed terrestrial Diverse including mobile and marine Key Pressure 1000-2200 psi Diverse including near atmospheric Fuel Type Metal clad ceramic Various: molten salt, Triso, etc Coolant Light water Various Industrial Application Primarily electrical generation Diverse including syn fuel/industrial Security Considered No Yes?

Fission Products well characterized Yes  ?

Neutron Spectrum Thermal Diverse