ML20210A256

Transcript of Commission 851107 Meeting W/Acrs in Washington,Dc Re Safety Goals & Emergency Planning.Pp 1-54

ML20210A256
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Issue date:	11/07/1985
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ORIGINAL l

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION

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In the matter of:

COMMISSION MEETING Periodic Meeting with Advisory Council on Reactor Safeguards (Public Meeting)

Docket No.

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Location: Washington, D. C.

Pages: 1 - 54 Date: Thursday, November 7, 1985

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' ANN RILEY & ASSOCIATES Court Reporters 1625 I St., N.W. r I Suite 921 l 951124 Washington, D.C. 20006 (202) 293-3950 l j7 7 2 851107 PDR.

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5 6 This.is an unofficial transcript of a meeting of the 7 United States Nuclear Regulatory Commission held on a 11/7/85 in the Commission's office at 1717 H Street, 9 N.W., Washington, D.C. The meeting was open to public 10 attendance and observation. This transcript has not been 11 reviewed, corrected,'or edited, and it may contain-12 inaccuracies.

g 13 The transcript is intended solely for general 14 infermational purposes. As provided by 10 CFR 9.103, it is 15 not part of the formal or informal record of decision of the

'g 16 matters discussed. Expressions of opinion in this transcElpt 17 do not necessarily reflect final determination or beliefs. No 18 pleading or other paper may be filed with the Commission in 19 any proceeding as the result of or addressed to any statement 20 or argument contained herein, except as the Commission may 21 authorize.

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t e-1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION 3 - - -

4 PERIODIC MEETING WITH ADVISORY COUNCIL ON 5 ~ REACTOR SAFEGUARDS 6 -- - -

7 Public Meeting 8

9 Room 1130 10 1717 H Street, N.W.

11 -Washington, D.C.

12 Thursday, November 7, 1985 13 14 The Commission met, pursuant to notice, at 2 :V S p.m.

15 COMMISSIONERS PRESENT:

16 NUNZIO J. FALLADINO, Chairman of the Commissioner 17' JAMES K. ASSELSTINE, Commissioner 18 THOMAS M. ROBERTS, Commissioner 19 FREDERICK M. BERNTHAL, Commissioner 20 LANDO W. ZECH,. Commissioner 21 STAFF AND.FRESENTERS SEATED AT COMMISSION TABLE:

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23 W. KERR 24 F. REMICK

'25 D. OKRENT -l i

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.l- 'Di WARD' I 2 D..MOEL' LEE-t 3~ J. EBERSOLE' 4 .C. SIESS

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-7. 'M. CARBON 8- P. SHEWMON

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9 C. MICHELSON 10 G..EEED.

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'2 CHAIRMAN PALLADINO: Good afternoon, ladies and 3 gentlemen. This is a periodic meeting with the Advisory 4 Committee on Reactor Saiguards. It was requested by the 5 ACES. There are three topics on the agenda: severe 6 environmental phenomena and emergency planning; safety goals;

, 7 ACRS effectiveness report.

8 I understand that Ray Fraley has indicated that the 9 committee will be prepared to give a status report on the 10- safety goals matter, and on the effectiveness report. I 11 understand that the appropriate documents have been made 12 available to the public, and we all look forward to hearing 13 the ACES views on these three important matters.

14 Do any of my fellow Commissioners have other opening 15 remarks at this time?

! 16 [No response.)

17 Okay. Dave, why don *t we turn the meeting over to 18 you.

19 MR. WARD: Thank you, Mr. Chairman, we're pleased to 20 be here again to meet with you. Of the three topics, we're 21 prepared only to make some very brief comments on Topic 2 and 22 Topic 3, and would expect to devote the bulk of the meeting to 23 Topic No. 1. So 1*d like to go ahead with that and ask 24 Dr-.'Moeller to lead the discussion.

,. 25 MR. MOELLER: Thank you. As you will recall, in a

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o V 1- meeting that-you held with us on July 11, 1986, Commissioners l

2 Asselstine, Bernthal and Zech asked it the committee would 3 review and evaluate the relative importance of various natural 4 phenomena in terms of their potential impacts on emergency 3 planning and emergency response.

6 COMMISSIONER THOMAS: Was that when Mr. Metzenbaum 7 gave me my vacation? Yes.

8 COMMISSIONER ASSELSTINE: 'I think that*s right.

9 COMMISSIONER THOMAS: I'm sorry I missed that 10 meeting.

11 MM. MOELLER: They did ask it we would look at 1

12 various natural events, and in a sense, as I understood it, i

13- the request to help set a sense of priorities or oiter guides 14 in terms.of the relative importance of the various events.

1$ And so we undertook to do that. And let me emphasize that we 16 do not mean, in our~1etter, that you can simply ignore a lot

, 17 of these events. We were mainly trying to help rank them for 18 ourselves and then to share'that information with you.

19 In our review, we noted -- and may others, of 20 course, already knew this -- that the frequency and severity

. 21 and indeed, the ettects of various. natural phenomena-are 22 site-specific because hurricanes occur in certain areas and 23 snow storms'in certain areas and so forth.

24 We,also observed that'the capabilities of plants to 25 withstand various events depend upon the design and so forth,

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1 1 but even here, what they're designed for covers quite a wide 1

2 range. And here I refer to the fact that when we met with the 3 experts on tornadoes, they pointed out to us that a typical 4 plant is designed for a tornado which perhaps has a frequency 5 of 10 to the minus e or so per year; in fact, one of our 6 experts said that he doubted that there was any possibility 7 that you-could ever find a tornado with wind speeds which we S use in the design.

9 So that*s a rather rare event in terms of the 10 magnitude of the particular tornado that we design for. And 11 then on the other hand, earthquakes, when we design for the 12 SSE, generally the numbers quoted, the frequency or 13 probabilities, are in the order of 10 to the minus 3 to 10 to 14 the minus 4 per year.

15 We also observed thirdly that the warning times that 16 are available for various natural-events cover quite a wide 17 range. And we saw recently in Hurricane Gloria that many 18 plants shut down or utilities shut the plants or brought them 19 to hot shutdown on their own accord. And you do have a

<20 warning time for a hurricane. And on the other hand, for an 21 earthquake, perhaps so far as'we know, people are working on 22 it but today there*s very little warning time, it any, for 23 that.

24 We also observed in consultation with the consultants

-25 and the stait members who' discussed this with us that the

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6- l 1 spatial impacts of the various phenomena vary widely, and 2 taking a hurricane'might sweep over a wine area, or a major 3 external flood might cover many square miles, whereas a 4 tornado is rather limited in its spatial-impact.

5 Well then having looked at these various 6 considerations, or having taken these various items or thoughts 7 into consideration, we then began to come down on where does it 8 lead us. And first of all, we concluded that the primary 9 concern, which is nothing new to you, but the primary concern 10 would be the seismic event.or the earthquake because it not 11 only, it it*s large enough it not only has a potential for

l 12 being an initiator of some problems at the plant,.but then it 13 can seriously attect cit-site capabilities for response- p 14 In response to Commissioner Bernthal, we specifica11y ,

15 looked, of course, at the contemporaneous-occurrence of a'n 16 earthquake which hampers off-site response with an unassociated 17 or some other caused accident at the plant. And we concluded 18 that the probability was so low'that that need not be a major 19 concern.

20 This does, though, bring up another paragraph in our 21 letter in that we suggested that some consideration be given 22 to a cutoit on certain natural phenomena. .It it*s probability 23 -is less than some number, maybe you could totally ignore it.

1 24 Now that is'obviously a subject of controversy.

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25 The statt -- a representative trom.the statt spoke

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1 to u :s this morning and pointed out that it we gave, or 11 you, 2 in consideration of. natural phenomena, 11 you gave a precise

~3 number, 1 times 10 to tho'minus 6, and it the probability is 4 'less than that, you can ignore it -- then, when challenges to 5 certain decisions came about, people might have a. tough task 6 in deciding whether this number was correct; that people would

? always challenge your number. So we believe that is certainly 8 a consideration, So earthquakes, they are the big things.

9 Secondly, then, we looked at the hurricanes and 10 external floods, and also the tornadoes, and our major 11 consideration there -- one of the major ones, as far as wo 12 were concerned -- is the potential loss of ott-site power. So 13 that has to be taken into consideration in terms of these

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14 events, and we also repeat that two of them, certsinty the 15 hurricanes and external floods, should have ample warning 4

16 time.

i 17 And then thirdly, we mentioned rains, blissards and a

18 togs and so forth. We -- I keep thinking about brush fires 19 olisite. Maybe somewhere we should have mentioned those.irt 20 the same category, depending again upon the site. But here we 21- said that rains, blizzards and togs can occur; they have a 22 high probability of occurring, they'irequently occur at 23 certain sites, but so far as we know, they:are not primary 24 accident initiators. Nonetheless, because.they occur so 25 traquently, they could-occuricontemporaneously with an l

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11 accident, and therefore, you must take them into account in 2 terms of their impacts, and indeed, you already do this. So

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3 we're.merely, again,'saying to you -- confirming the current 4 practice.

5 Now there were some items'in addition -- those are

.6 sort of the bottom lines, but there were some other items that

7, I wanted to bring to your attention where we did not 8 necessarily address it directly in our letter. Perhaps we 9 should have. And there were three of these items, and let me 10 just mention them so you'll know what we're. talking about.

11 One is the question: what is the adequate 12 consideration of an earthquake in terms of its impact on 13 ott-site emergency response. In one of our letters to you we 14 said that the TEMA study -- you know, done for Diablo Canyon 15 by FG&E -- we said that that-clearly meets the intent of the 16 ACES recommendation; in other words, _that was clearly adequate.

17 Now, the stati came back in a response and said v 18 they thought well, that probably went beyond what is 4

' 19 necessaty. And other committee members may want to comment on 20 this, but I would simply point out'that'where we.say'it 21 clearly meets the intent, it could also exceed what is clearly a

4 22 necessary, i

23 The second item along these lines that I wanted to 24 bring to your. attention is our related letter on the proposed 25 final amendments to 10 CFR 50, ' Appendix E, on the consideration e

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9 1 of earthquakes in emergency planning. And there, we brought to 2 your attention-what we considered a potential problem in that 3 the stati said the main thing we want to assure that the 4 utility has is the capability to supplement the statt at the 5 plant in case of an emergency.

e- Well, one or two committee members raised the

? issue: what it the release around the plant has resulted in 9 exposure rates that make it very ditticult for you to transport 9 these supplementary people in? Have you given consideration to 10 this? And the impression, as I recall, was that no, adequate 11 consideration apparently had not been given to that particular 12 potentiality.

13 And then the third item I wanted to mention was 14 specifically a note trom Commissioner Asselstine in which he 15 asked the committee -- and we really didn't address it, and we in wanted to; we just didn*t do it -- you asked us in the July 17 5th, 1985 memo from the EDO, you said, Does the committee 18 accept the probabilities of occurrences of earthquakes as 19 quoted in that memorandum. And I think, -- again, oth9rs may 20 want to comment -- in general I think yes, we tend to follow 21 along with the probabilities quoted there, and let me just be 22 specific.

23 Again, the SSE we mentionad in one of our letters as 24 having a probability in the range of 10 to the minus 3, to 10 25 to the minus 4 per year, with tremendous uncertainties. That

EU 1 doas not mean we have developed this number and we're putting 2 it torth;-it's simply'that in general, that is a number that 3 is used and that we have, indeed, quoted in one of our letters.

4 And then specifically for Commissioner Asselstine, S' in terms of the probability of a very severe event, meaning 6 beyond the SSE, or two to tour times the SSE, as I believe was 7 quoted in the EDO memo, he quoted.a number of 10 to the minus 8 4 to 10 to the minus 5 per year, and perhaps Dr. Siess and 9 Dr.'Okrent would want to comment further on this. Eut as I 10' understand from them, when you go to two times the SSE, you're

11 sort et going up one order of magnitude, and it you go tour

12 times the SSE you're sort of going up two orders. So 10 to i 13 the minus 4 to 10 to the minus 5 seems to be appropriate 4

14 compared to the to to the minus 3 to 10 to the minus 4 tor the 15 SSE.

le So, Mr. Chairman, that is briefly our report, and 17 we*re certainly, of course, open to questions and discussion.

18 CHAIRMAN PALLADINO: All rignt, thank you, Dade. I 19 hadlsome questions that came out of your October 10th memo, 20 and maybe it's best it I just went~through them as they. appear 21 rather than try to take the most'important first.

22 On page 1 down under Evaluation No. 1, it says, 23 "Similarly, the ettects'of blissards might be a consideration t

24 for plants.in the North but would not_be significant for the 25 plants in the South." Now, shouldn't this depend on the r e a

11 1 trequency of bli::ards in the South as compared to the 2 threshold, whatever it might be? Have we studied to make sure 3 that blizzards haven't existed in the last 1000 years in the 4 South? And that would only be 10 to the minus 3. If you want 4

5 to go 10 to tne minus e, you say blizzards haven't occurred in

$ the last million years. If that's the threshold.

7- We seem to here casually separate things, and I

-8 think they should relate to whatever threshold we might set 9 and the probabilities of such events.

> - 10 MR. MOELLER: Undoubtedly, it should, and as I see 11 the word " Sun Welta I personally would have been thinking of 12 Florida. And has J lived in Atlanta. I know we*ve had -- Tom 13 knows -- we've had major blizzards there with ice storms and i

4 14 it can be very bad. So certainly, surely, you'd have to look 15 at the probability for's given grea.

16 COMMISSIONER BERNTHAL: In Memphis last year, 17 CHAIRMAN PALLADINO: I think it's important because 18- the implication is that titore are some. things we can obviously

19. dismiss, but --

20 MR. MOELLER: -No, I think that is one flavor wnich 21 the stati commented on this morning, which'tends to be in our

22 letter, and we did not intend it. We don't mesn completely 23 ignore it. We think that 411 o1 the factors that you 24 co.sidered need to continue to be considered, and we were i

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25 simply trying to help. rank them.

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1 CHAIMMAN PALLADINO: Okay. Starting at the bottom 2 ot page 1 and going to the top of page 2 is a sentence that 3 says, "For example, plant designs to withstand the impacts of 4 a design basis tornado are based on events that may have a 5 probability of occurrence as low as 10 to the minus 6. Isn't 6 the question as to how high the probability might be, not how 7 low it can be?

8 MR. SIESS: It probably should have been high.

9 CHAIRMAN PALLADINO: It said "as low as." And it*s to misleading because what we're interested in is how high might 11 it be. Now, 11 you say that was an error and it should be "as 12 high as," then I could understand.

13 MR. MOELLER. This letter has already been corrected 14 once, maybe we*11 have to correct it a second time.

15 COMMISSIONER ASSELSTINE: But, Joe, I thought the 16 point of that sentence, as well as the following one, was 17 really, though, to kind of ditterentiate this between tornadoes 18 on the one hand where you say it you look at the tornadoes for 19 purposes of design basis, it's about at the 10 to the minus e 20 level; whereas, you have probabilities --

21 CHAIRMAN PALLADINO: Well you see, when I read "as 22 low as" I wasn't sure that that excluded 10 to the minus 3 to 23 10 to the minus 4, for as high as.

24 MR. MOELLER: What we were trying to say -- and as I 25 recall, it was Dr. Abbey, Robert Abbey who used to be leith the

13 1 1 Commission, who gave us a very nice presentation on this, and 2 he pointed out, to repeat, that the design basis tornado is 3 out of this world, you know. He says you will never see it, 4 and never is a long time, of course.

5 COMMISSIONER BERNTHAL; If I may ask a question 6 about that, since 1 -- I find much to agree with in your 7 statement since I think with one major exception it agrees 8 with what I presume to be the case. But the tornado thing 9 troubles me a little bit because I looked into that rather 10 carefully at one point based on my initial thinking, and it 11 was only thinking, that tornadoes and earthquakes were in a 12 class all to themselves.

13 And when we Icoked and in fact called the Naticnal 14 Center for Atmospherio Research in Boulder who referred us to 15 somewhere in Oklahoma, as I recall, the best numbers we were 16 able to get at the time, although they were somewhat out of 17 date, indicated that in rather large areas of the country --

18 and I'm operating purely on recollection now -- the probability 19 tor a given area -- I guess I ought to have the size of the 20 area, but for a given spot of ground -- to be struck by a 21 tornado was surprisingly high, like once every 100 years 23 MM. MOELLER: You're correct, but the tornado that 23 strikes will not be as bad as what the plant has been designed 24 to withstand.

25 COMMISSIONER BERNTHAL: That's precisely the point

o i 14 1 that I was having trouble with because the tornadoes -- there 2 are tornadoes and there are tornadoes. And in fact, I was 7 disputing what we were told based on that because there are 4 very tow tornadoes that have, tirst of all, a very wide path 5 of travel, in my recollection -- I won't say experience. And 6 secondly, there*s a wide variation in the intensity of those 7 events. And that also seemed not to be taken into account in 8 what was given to us at the time. But I take it you've looked 9 at that now, and that*s reilected in this 10 to the minus 6 10 number.

11 MR. SIESS: What you need to keep in mind is that 12 that letter was addressed to the probability of extreme

13 external events beyond the. design basis. We still make the 14 assumption that it an earthquake or a tornado or a flood 15 occurs that is within the design basis, there is not likely to to be a LOCA.

l 17 COMMISSIONER BERNTHAL: Okay. I understand that.

18 MR. SIESS: Now, the design basis tornado is 360 19 miles an hour combined translation and rotational speeds.

20 COMMISSIONER BERNTHAL: And those are rare events, 21 that's for sure.

22 MW. SIESS: Some people think they're impossible.

23 Mr. Pageda gave us the number I think and it was the biggest 24 thing he could think of at the time.

25 COMMISSIONER BERNTHAL: That explains --

15 1 MR. SIESS: It*s the probability of beyond the 2 design basis event.

3 COMMISSICNER BERNTHAL: Well, that explains then 4 both my skepticism over the numbers we'd been given and 5 explains how you come up with this very small number. And 6 however we decide to come down on the issue at earthquakes r

7 it suggests to me that the thought that tornadoes belong in a 8 separate class is entirely valid; they do. And it also 9 suggests to me that some of the things we've been doing like 10 tor places like the bottom of the Hudson River, for God *s 11 sake, the Valley in New York, are totally unrealistic for the 12 kind of event that we're talking about here. Based on what i

l 13 you ve said and the letter you*ve written, at least that*s my 4

14 impression.

15 MR. SIESS: I was pointing out earlier that all ot 16 these are plant-specific and site-specific, and we should keep i

17 in mind that there are some plants that were not designed for 18 a tornado as large as we now design for, particularly some of 19 the SEP. plants. And they are being upgraded to something I 4

20 believe less than the 10 to the minus 0 tornado but not down Y

21 around 10 to the minus 3, I don *t think. It*a sort of a 22 cost-benefit sort of thing, to try to move down the curve.

23 So all are not created equal, or even made equal, 24 given time.

47 25 .COMMIS810NER BERNTHAL: Okay. Anyhow, I appreciate

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1 the work you've done on that because trankly, I was confused.

2 CHAIRMAN PALLADINO; Okay, can I continue on with my 3 questions.

4 Going to page 3, the first point, 3, on the page, I

$ wanted to try and interpret it based on what*s said. And let 6 me ask it this is what you're trying to say. Is it natural 7 phenomena having a probability of occurrence greater than 10 8 to the minus 6 per year should be considered in ott-site 9 emergency planning, and that phenomena of less than 10 to the 10 minus 6 probability should not? Or 11 you had some other 11 number in mind let us know, because you do refer to the 10 to 12 the minus e, and when I'm all through I wasn*t sure whether 13 you were saying that*s the cutoit That we should have such a 14 cutoit.

15 MK. MOELLER: I do not believe that -- we were 16 citing this as an example. We were saying, tirst of all, that 17 it might be useful to have a cutott; it the event has a 18 probability of less than some number it could be ignored. And 1

19 we then said to ourselves, is there any precedent for this, 20 has the Commission already done this on something else. And 21 we found out, or we knew, that for ott-site events, and these 22 are mainly man-made as I recall, ott-site events, explosions 23 and so torth, you did have in the Standard Review Flan-such 24 an approach. And we suggested that consideration be given to 25 applying a similar approach to natural phenomena.

'- 17 1 Having said that, though, let me repeat that the 2 statt says that could get them into trouble, in terms of 3 proving that the given ott-site event had more or less

'4L probability than this cutoit.

5 CHAIRMAN PALLADINO: I could understand the 6 ditticulty of proving it.

7 MR. MOELLER: Hight. They prefer not to get into 8 that.

9 CHAIRMAN PALLADINO: Wut still, you're implying ,

10 there is a cutoit. It'you don't. support the 10 to the minus 11 6, then I have to ask you what's the support --

12 MR. MOELLER: We have not --

13 CHAIRMAN PALLADINO: Let me tinish. Because you r.

14 just said that for several times beyond the SSE, it's 10 to 15 the minus 4 to 10 to the minus 6 so it you don't support 10 j 16 to the minus e, you're getting in a. range where earthquakes 17- come in and may be below your cutoit i

4 18 MR. MOELLER: My answer -- and others can comment -- i 19 would simply be.that we_have notfgone.intolthis; we have not 20 discussed it as a committee, we really didn't discuss it even -

i 21 as a subcommittee. And I would not be prepared to give you ,

22 any kind o f la number, s 23 CHAIRMAN ~PALLADINO: 'Well, that's important for us 24 to know because there is an implication. hero.that you're 25- supporting 10 to the minus 6, and I-have no objection to-your-

1 supporting it; I'd just like to know what it is -- I 2 MR, MOELLER: I don *t think we are.

3 MR. SIESS: Well, 10 to the minus 6 would not cut 4 oli earthquakes beyond the deaign basis.

5 CHAIRMAN PALLADINO: No, but if you didn't support 6 10 to the minus 6 and you moved that up, you might come into 7 where you encompass this several times an SSE.

8 MR. SIESS: Well, two SSE'S are tour to tive, and 9 tour SSE*s which it took to do Zion in, are five to six. And to we still think that ought to be considered.

11 CHAIRMAN PALLADINO: No, no. All I'm saying is 11

. 12 you're going to have a threshold and you don't support 10 to 13 the minus e, where is it. And then we can decide whether 14 something's below it or not.

15 MR. SIESS: We've always. supported the stati's 10 to 16 the minus 6, 10 to the minus 7 on airplane crashes --

17 CHAIRMAN PALLADINO: Well, I'm asking you is that 18 the cutoit that you're suggesting, and I'm not arguing whether 19 it should or shouldn*t be. I'd just like to know.

20 MR. OKRENT: Can I otter seme comment t ha t- I think 21 will relate to the issue. First,.I think when one looks at 22 the FRA*s that are, let's say, in the class of the eighties, 23 'the more recent period, usually an event that leads to I

24 significant release beyond the containment is something times 25 101to the minus 6. You don't generally find something times

89 1 10 to the minus 3 or 10 to the minus 4. So core melt trequency 2 is more common than a large release. But the large releases 3 are usually larger than 10 to the minus 6 per year.

4 The second thing is that --

5 MR. WARD: Do you mean larger or at a smaller

.6 trequency?

? MR. OKRENT: No, they're calculated to occur at some 8 .trequency i a few times 10 to the minus e, and that was the 9 case in WASH-1400, in fact. 11 you looked at their worst to release. Like the V sequence, for example, with sometime 11 times 10 to the minus 6.

12 So 11 you're doing emergency planning for large 13 releases, you're doing emergency planning probably for things 14 that tall between 10 to the minus 3 and 10 to the minus 6 per 15 year. That seems to be what we're at least learning from the 16 FRA*s.

17 The other point 1*d like to make is it at some point 18 you start reconsidering emergency planning in view of source 19 terms, there are going to be a range of scenarios. And not 20 all the scenarios will lead to a - small source ttra -- pressure 21 vessel failure, for example, which is one I know Chairman 22- Palladino thought of in the distant past.

03 CHAIRMAN PALLADINO: I did?

24 But 11 you decide that the frequency of this event 25 is low enough that it need not be considered in emergency

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o 20 1 planning, even though it might lead to some -- it would 2 influence what you thought the distance or the kind of 3 preparations that one did in emergency planning. So 4 eventually, it not now, you're going to have to have in mind a 5 range that you say is some kind of a cutott; we'll plan for 6 things that are more than this and not for things that are

? less than this.

8 And I would guess that it*s going to be in the 9 vicinity of 10 to the minus 6. This is my personal guess, 10 CHAIRMAN PALLADINO: Okay. What I think I heard is 11 .that there would be value in the cutott; it might be ditticult 12 to detend, but even though perhaps as a committee or 13 subcommittee you haven't explored it in detail, there is 14 teeling among some of the members that it is about the order 15 of 10 to the minus o. And that's all I was trying to find to out.

17 MR. REMICK: Mr. Chairman, I*d like te make a 18 comment. My judgment tells me I shouldn*t make it because I 19 want to be constructive and yet'I want to make a point. .We 20 throw numbers around like 10 to the minus 6 and 10 to the 21 minus 7, but there's probably a natural phenomena that we 22 should consider that's something less than that, and that 23 would be a glacier. That's probably a higher trequency.

24 So we throe these numbers around, and I do it, too;

, 2d we talk one in a million years, and --

21 4

1 CHAIRMAN PALLADINO: That's why I raised the question 2 on blissards, because 11 you're talking about those kind of 3 numbers I*11 bet you it you go back in time and you*11 tind 4 some pretty severe bitssards.

3 MR. OKRENT: 'But we have advance warning.

6 MM. WARD: I think we do. They move glacially, I'm 7 told Yes.

8 [ Laughter.1 9 CHAIRMAN PALLADINO: Well, that brings me to my --

10 MM. OKMENT: I think we*ve thought about glaciers.

11 MM. WARD: Well, it we haven *t, we*11 have time to, 12 I think.

17 [ Laughter.2 14 CHAIRMAN PALLADINO: I think I know the answer to 15 the next question, but one of my stati raised it and I'm going to to raise it anyhow. Does the committee believe that tornadoes, 17 hurricanes and external floods need not be considered in 18 ' emergency planning because of the warning time associated with 19 them? A corollary question: what role does the warning time 20 play in the commattee*s view? The first question is: -does the 21 committee believe that tornadoes, hurricanes and external 22 floods need not be considered in emergency planning because of 23 the warning time associated with them?

24 MM, MOELLER: We certainly believe they should be i

25 considered,

22 1 CHAIRMAN PALLADINO: That's what I thought.

2 MR. M0ELLER: Of course, they are an emergency unto 3 themselves, exclusive of the plant.

4 MR. EWERSOLE: Can 1 make a minor comment? There 5 are certain floods, in the Tennessee Valley, that are 4 postulated to be earthquake-driven; they come very tast. They 7 may not obtain the highest height of the classical flood, but 8 they can grow to damaging heights. And they come up pretty 9 tast.

10 CHAIRMAN PALLADINO: Well, I was also thinking of 11 dans that break suddenly.

12 MR. EWERSQLE: That's what I mean. It*s a cascade 13 of tailures.

14 CHAIRMAN PALLADINO: And they have broken suddenly, 13 and many of our plants are on rivers.

16 MR. EWERSOLE: So the plant doesn't see the 17 earthquake, but it sees the flood that results trom it.

18 CHAIRMAN PALLADINO: I guess we*ve even had dans 19 that broke without earthquakes.

20 MR. dWERSOLE: And I want to make it clear that the 21- highest level flood may not be the most damaging one, so when 22 it comes up to testus wherein you don't have time to fix 23 yourselt up for it.

24 CHAIRMAN PALLAwlNO: Well, I think this question of 25 warning time is a very interesting one, and I do abmit that r

/

_ . _ . . . _ . . _._m _ _ . _ _ _ __._.___.______...___._A

23 1 earthquakes don't give much warning time. But I think in 2 considering warning time there is the question of other events 3 that come on suddenly.

4 A couple more questions and then If 11 quit and give

$ it to somebody else. With regard to -- still on page 3, on 6 the first of the recommendations -- I'm sorry, they otter the 7 to11owing recommendation. Yes, it is a recommendation.

4 3 Does the committee's first recommendation on page 3 9 in essence require analysis for each plant in the United 10 States like a TEMA? I promised myselt I wasn't going to use 11 that word, but that*s the easiest way to identity it.

12 MM. MOELLEE: We said that that is clearly adequate.

13 I think a number of us believe it goes beyond what's needed.

14 But we believe you need to consider the potential impact of the

, 15 earthquake on ott-site response. And we have said that does 16 not mean strengthening all the bridges; it mainly means i

17 deciding whether they would withstand the earthquake, and it 18 they will not, what alternative evacuation or is sheltering 19 better in cert'ain situations and so torth.

20 CHAIMMAN PALLADINO: Mut you do envision an 21 individual study for each plant 22 MM. MOELLEM: Yes. Yes, we do.

23 4 CHA!MMAN PALLADINO: Now also in that same point, 24 there's a statement later on that says, "Nonetheless, b e c. a u s e 25 sucn earthquakes have a tinite probability of occurrence, we B

. n. ,

, r+ , ~

'l s to a, 4 24 1 recommend that such vent >s require appropriate limited 2 consideration in cit-site emergency planning." Now, does this 3 mean that consideration must be given to such earthquakes, no 4 matter how low the probability? Weoause finite is anything, !

4 believe, above sero; maybe even below stro. 1 don't know.

6 It says because it's finite, afou can always do 7 something about it, and,I don *t know that that*s truly what 8 you meant. ,

9 MR. MOELLER: We searched and deliberated over that 10 sentence quite a bit.

11 COMMISSIONER ROWERTS: Appropriate limited 12 consideration.

13 MR. MOELLER: Right. ,,

14 CHAIRMAN PALLADINO: Rut it also says, "Wut because 15 they are itnite probability..." -- -

to MR., MOELLER: We are saying thathquneed to give 17 them appropriate limita~d consideration.

.6 * , ,

14 [ Laughter..)

19 Even for the ones beyond the SSE, yes, that's what 20 we are saying.

21 CHAIRMAN PALLADINO: No matter how low the frequency 22 might be.

23 '

MM. OKMENT: No, because there is a 10 to the minus 24 'n suggested.

23 CHAIRMAN PALLADINO: So you do the that 10 to the

i J

25 I

1 minus 6 in.

2 MR. OXRENT: Yes.

3 CHAIRMAN PALLADINO: Now, where is the thing that 4 says tornadoes are-placed in this category. Oh,-yes. And I

$ believe you mean secondary importance because of their limited 6 spatial impacts and conservatism that exists in the design of 7 -nuclear plants to resist their impacts.

8 Well, I don *t understand why you are worried about 9 -- no, it you are going to give consideration to the 10 conservatism of the design with regard to tornadoes, should 11 you also give consideration to the design conservatism in the 12 resistance earthquake?

13 MR. MOELLER: We probably used or could have used 14 better worda there.

15 We meant, once again, the tact that the design basis 16 tornado is such a, you know, hig, beyond what is anticipated.

17 CHAIRMAN PALLADINO: Well, I think many of the 18 earthquakes that we postulate are in that same range. Rut, 19 oven -- let me stick to your statement.

20 A tornado can blow out a switchyard and deny olisite 21 power, And with the. frequency or the infrequency with which 22 -- the frequency of diesel starts could lead to a station 23 blackout and this could give you a'st'tuation where the.otisite 24 ettect can lead to an incident, 25 And I was reading one of the plants were without

26 1 this, where they had lost olisite power and lost the 2 ctosels. The instruments in the control room got up to 90 3 degrees and some of them began to malfunction. And some of 4 them that were functioning, were -- some of them stop 5 tunctioning and some of those that were functioning were 6 giving the wrong answers. And without instruments you have y

7' ditticulty controlling the plant.

8 MR. SIESS: Now you have to postulate that the same 9 tornado-has upset the evacuation routes, the communications 10 systems, et cetera, et-cetera, et cetera.

11 CHAIRMAN PALLADINO: I agree. I am licking on 12 individual points. I am trying to understand your position.

13 MR. SIESS: Again, the event has to do two things.

14 It has to affect emergency evacuation or sheltering, and 15 cause an accident. Sometimes the combined probabilities.are 16 less than the probability of either one.

17 CHAIRMAN PALLADINO: But, just leading to a route 18 that'bhows you could have an accident and I*ve seen --

19 MR. SIESS: You want ~ to go back to your glacier, 20 Joe. How many people are going to be around to evacuate when 21 a glacier gets'here? h 2'2 CLaughter.3 l 23 9 CHAIRMAN PALLADINO: They will be gone. And once l

24- they are gone you' don't need;the plant.

25 Well, those are some of my questions. And they-

27 1 were, honestly, in the interests of understanding and not to 2 -- in an adversary sense.

3 COMMISSIONER BERNTHAL: I have to say as an old n

4 Nebraska boy that I was convinced that somebody underitood 5 tornadoes as a phenomenon. And I still have serious questions 6 the other direction now about your knowledge.

7 I find it hard to believe, given the numbers that I 8 was first introduced to sometime back, several months ago, of 9 10 to the minus 2 probability of eventually being t ft by a 10 tornado.

11 What you are effectively. telling us is that only one 12 -in 10,000 approaches this really major killer, c'atastrophic 13 event. That does not seem like --

14 MR. SIESS: I think it is limited more by physical 15 phenomena than probabilities.

16 MR. EBERSOLE: Mr. Bernthal, did you have a storm 17 house in your retreat system?

- 18 COMMISSIONER BERNTHAL: No. But the town I lived 19 in, there was an old I,n d i a n legend-that said a tornado would

. 20 never hit. It'never has.

21 ELaughter.]

22 MR. EBERSOLE: I was going to'say I' think this kind 23 of tornado would be the kind that would uproot a tornado 24 shelter.

25 COMMISSIONER BERNTHAL: So you are, basically saying m._.

.o

• 28

-1 that we are designing -- our design basis for tornadoes is 2 totally unrealistic. Nobody has ever observed a tornado or it 3 is questionable whether a tornado like that has ever o c c' r*'

4 MR. EBERSOLE: I don't think that is th. . ;f 5 is not quite that good.

6 MR. SIESS: There are very few m i + r . .e .. : ( 21 wtgw

? velocities from tornadoes. In the past 1 *t )  ?,,j have 8 made some progress of looking at movies and trying to calculate i

9 what speeds it took to fly a barn door, or Volkswagen or 10 something.

11 COMMISSIONER BERNTHAL: Or, to drive a straw through 12 a telephone pole, more to the point, which happens.

13 MR. EBERSOLE; Well, to drive a chicken larm into 14 the diesel intakes would be more damaging.

15 MR. SIESS: 360 miles an hour will do an awful lot 16 of things. Meteorologists -- I don't think there is any of 17 them that ever felt that that was other than a maximum 18 conceivable type of thing.

19 I remember Pagoda said that, Abbey has said it more 20 recently. And whether their conception is likely to change as 21 they get older, I don *t know.

- 22 CHAIRMAN PALLADINO: Can I'come back to this warning 23 bit. I. recall a recen't' earthquake just south of Erie,.

24 -Pennsylvania. I don *t remember the exact town. It came on 25' 'rather suddenly, with essentially very little or no warning, n-y , , - - -

e 29 1 and it-was devastating to the area.

2 It did disrupt roads and the like.

3 MR. SIESS: You said earthquake.

4 CHAIRMAN PALLADINO: I meant tornado. Sorry. Thank 6 you.

6 With regard to tornado. It was a tornado in that 7 area. And they got very little warning. And it was -- it did 8 do a lot of devastation.

9 MR. EIESS: You get ten minutes. We get tornado 10 watches and tornado warnings, and when they start the sirens, 11 that means that one has been sighted. And, it it is anywhere 12 near you have got maybe three minutes to hit the basement.

13 What most people do, they go outside to look for it.

14 CLaughter.)

15 But, you know, you get plenty of warning. It'you 16 want a nuclear plant - when you see them, you get a tornado 17 watch when the conditions are appropriate for them. I think 18 there are no plants that are willing to shut down'on tornado 19 watch, because that is a very speculative thing.

20 But, most of them will start to shut down it there 21 has been warnings within a certain area.

22 CHAIRMAN PALLADINO: Yes, I'm'not familiar enough 23 with that to say who got what warning.

24 MR. SIESS: In Illinois we see them every day, i

25 COMMISSIONER BERNTHAL: 'I have one other, and I will

e .

30 1 not interrupt here further. But we are on this subject and I 2 would like to air it.

3 I have one other quibble with the presumption that 4 seems to be behind your tornado scenario here, and that is the 5 presumption that these events are so confined in the area of 6 their influence. Now, for maximum influence, that is of 7 course true. But, they are always accompanied by very severe 3 weather over a broader area that is quite capable of knocking 9 out every power line and very otten very heavy rains and very 10 high winds. That is exclusive of the tornado itself, 11 And it is not so clear to me in that respect they 12 are so very much ditterent from earthquakes as well. Because 13 you look at earthquakes, and once again unless you have a huge 14 area of soil liquefaction phenomena or something, somewhat 15 like Mexico City, maybe, very spotty that the severe damage 16 occurs. It is a very unpredictable kind of thing.

17 MR, EBERSOLE: Well, it is critically important that 18 the tornado not damage the diesel. plant, of all things. So, 19 you have to look at the whole spectrum of possibilities for 20 the diesel plant damage',

21 And I did mention, and not jokingly, it you-live 22 next to a poultry farm, and plug the diesel intakes with 23 chickens, you would be in big trouble.

24 Chaughter.3 25 . CHAIRMAN PALLADINO: I happened.to-be in an airplane l

31 1 that sucked in a bunen of sea gulls. We were in trouble.

2 MR. EBERSOLE: So, there are barriers and torturous 3 paths and all sorts of things.

4 COMMISSIONER BERNTHAL: But the odds of a tornado 5 hitting a diesel are, indeed, very low.

6 MR. S1ESS: It is the missiles. It is the tornado 7 missiles. Ti.e winds are not a design problem. It is designing 8 against airborne tornado missiles.

9 The Statt has a spectrum of missiles ranging from 10 schedule 80 pipe such and such a diameter, to a telephone 11 pole, and up to 30 feet, one Volkswagen. I think it was a 12 Beetle. Maybe they have changed it to something else, because 13 there are not many Beetles around.

14 [ Laughter.3 15 But, it is the tornado missile that is the problem.

16 And then there is multiple missiles. And it gets into some 17 real complicated probabilistic approaches now, because there

18. would be tour things you have to hit. Two diesels. And maybe 19 -Jesse can tigure out one thing you can hit.

20 But, it is'the tornado 1 missiles that you have to i 21 worry about.

20 COMMISSIONER BERNTHAL: 'True. But, by yourLown 23 argument, small probability. And that is what.you are arguing, 24 basically, 'small probabiltty. l i

25 And then whether it is-missiles,:or-whether you are l

o 32 1 actually in the tunnel, it is a small diameter area.

2 MR. SIESS: Much of the missile design tends to be 3 independent of the magnitude of the tornado, because it is 4 really getting things inside or separation.

5 COMMISSIONER BERNTHAL: My point is, however, with 6 respect to the accompanying weather event, that I still do not

? see, except -- and I take the point -- except that we may be 8 -overdesigning in terms of -- or making overly conservative 4

9 assumptions in terms of probabilities than I am prepared to 10 accept, but I think the accompanying weather phenomena are 11 larger in area where the severe damage, to be sure, is very 12 contined, but therefore it strikes me that the parallel is 13 still pretty good with what you get irem an earthquake.

14 MR. SIESS: But you don't get much more than with 15 thunderstorms, which everybody knows how to take care of 16 But a tornado could take out that one bridge it it 17 was impor t a nt , just as. easily as an earthquake could take out 18 that one bridge it it. hit it. .I mean, it one bridge'is 19 important to your access, it is site specific.

20 COMMIbSIONEN BERNTHAL: But you just told us that 21 that is a 10 to the minus 6 event.

22 MR..SIESS: That's right~,

23 COMMISSIONER BERNTHAL: That the tornado itselt

.24 What I am arguing is that it is'the associated phenomena that

~

25 may take out the bridge, a much higher probability.

, o 33 1 MR. SIESS; The thunderstorms are not much of a 2 deterrent to evacuation, I wouldn't think. And they are 3 certainly conducive to shelter.

4 COMMISSIONER BERNTHAL: I'm sorry, I don't buy that.

5 CHAIRMAN PALLADINO: Some people had some trouble 6 getting in today because of floods.

7 MR. SIESS: Yes, but this happens often enough in 8 washington that they are runnir g the busses instead of the

.9 trains.

10 Any disaster management agency would have plans for 11 bad weather just like you would for snow. And, as I said once 12 betare, you are not going to make them worry about glaciers, 13 no matter what-you think. You can tell them, but they won *t S

14 do it 15 COMMISSIONER BERNTHAL: Well, it is enough on 16 the subject.

17 CHAIRMAN PALLADINO: 10-to the minus 6 does sound a 18 little low. But, your judgment on this is much better than 19 mine.

20 Let's see it there are others.

21 MR. REMICK: Mr. Chairman, if I may comment.

22 -

The tornado you talked about was an interesting 23 one. It was actually farther south. It went .through 24 Quenanna[ phonetic 3. It had some unusual-aspects. There was 25 warning.in the area, but not specifically. They. knew that the.

~

34 1 whole central region of Pennsylvania was a tornado alert 2 But the experts, the meteorologists -- one who you 3 know, Charlie Hostler, indicates that without the doppler 4 radar, they cannot give the warning that we expect that in 5 this community at such and such a time. Until they have 6 doppler radar, they can't do that.

? But there was an alert hours -- basically in the 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> before.

9 That was a very unusual tornado, they tell me. One 10 of the largest, perhaps. It was about a halt mile width, and 11 30 some miles long. Quite large.

12 CHAIRMAN PALLADINO: Yes, that is what I remember.

13 I don't remember specific figures, but what I read left me 14 with --

13 MR. REMICK: Wind speeds I don't know. I have no 16 idea.

17 MR. SIESS: That sounds like Xenia. Xenia was about 18 a half mile wide.

19 CHAIRMAN PALLADINO: Jim, do you have questions or 20 comments?

4 21 COMMISSIONER ASSELSTINE: I think I had -.I won't S

22 prol'ong this very much longer. I'know we have got-two other 23 -topics.

24 . Joe, you. pretty much covered my questiona about the- j 25 threshold and I think I now understand the Committee's views l I

I

r r

1 on the 10 t o.. t h e minus e, in that-general range.

2 I guess the only other question I would ask- is, in 3 terms of what kind of consideration ought to be given in the 4 earthquake situation. You say perhaps something less than the

$ TERA report. The Statt has said perhaps something less than 6 the TERA' report.

7 Is it possible to refine that a bit more in the 8 event that the Commission were to proceed with a rule to 9 require site specific consideration of that kind of issue?

10 Or, have you said about as much as you think you 11 should say in terms of the kinds of preparations that ought to 4

12 be done in planning?

13 MR. MOELLER: I think we have said about as much as 14 we can.

15 The main thing, to repeat, was to consider which-to bridges or which mud or landslides and so.torth might occur 17- and what they might do.to the response. -Not that these things 18 all-need:to be shored up.or strengthened, but rather what-19 impact would they have.

20 COMMISSIONER ASSELSTINE: I guess the only other 21 thing I'would add is Just a comment, since I was one of the 22 ones who. asked you allyto take a look at this.

23' I found both ot-your letters very helpful and very.

24 thoughtful, and I thought they brought some= good insights to 25; what has been a tough and ditticult' question. I ~ very much

t o.

30

1. appreciate the letters and'the ettorts that went into them.

2 MR. MOELLdR: I must say it was very helpful for 3 us. I personally appreciate your asking the question.

4 CHAIRMAN PALLADINO: Do you plan to correct that one d part about "as well as"?

6 MR. WARD: We will. Yes.

7 CHAIRMAN PALLADINO: Lando?

8 COMMISSIONER ZECH: I would just like to make'sure 9 on the tornado situation -- I think I understand what you are 10 -telling us, but I guess essentially you are saying that the 11 probability is something like 10 to the minus 6. And that 12 probability is so low that tornadoes would not cause the type

, 13 of damage that we would be concerned about in an emergency 14 planning event.

15 I guess that is what I think you are saying.

16 MR. MOELLER: Well,.I think what we are saying, to 17 me more importantly, was that the-tornado that damages the 18- plant would not necessarily disrupt olisite.

~

19- COMMISSIONER ZECH: Right. And~the main damage from 20 tornadoes is the missile problem.

21 MR. MOELLER: Right. And it it damaged olisite and 22 missed the plant, then there is no.need --

23 COMMISSIONER.ZECH: Right. You are saying that the

~

wind damage ~ trom_a tornado.is such.a low probability that we 25 need not he more concerned with it than that.

L

37 1' MR. OKRENT: Is the wind damage to the plant 2 sutticiently severe as to cause a nuclear accident?

3 COMMISSIONER ZECH: Hight. Very good. That is an 4 important point. I appreciate that.

5 MR. SIESS: There is some margin in the designs.

6 COMMISSIONER ZECH: Right. All right, thank you.

7 The only other thought I had at all was, I was very B interested in your words which we have already mentioned, 9 " appropriate limited consideration." I'm sure they were very 10 esrefully considered.

11 Does that mean anything more than the five at us may 12 kind of decide in our own mind what it means? Are you trying 13 to tell us anything in there?

14 MR. REMICK: Unfortunately, when we were writing 15 that letter, I think I suggested that we condition those 16 particular words. And the thing that I was trying to get at, 17 and I think the Committee agreed on, we were_not suggesting -

18 that bridges or highways be designed against earthquakes.

19 What we are trying to do is suggest that it is a 20 communication system. You have to make sure that you have 21 ilexibility in emergency plans, and alternate routes are i

22 thoughtLout. Maybe you don't evacuate, maybe you shelter I

23. people and so forth. That is what ~ we were trying to get at 24 with those words. j l

1

.25 . COMMISSIONER ZECH: Very gvod. 'I'm glad you  !

l

. ~ . , _

l l

.-

• 38  ;

1- explained that. I appreciate it. That is very helpful 2 The words ars very interesting and I think do need 3 an explanation, and I appreciate it.

4 MR. MARK: Your reference to communications, it will 5 be in everyone's mind, but might be mentioned. There was a 6 really serious gap in-communications in connection with the 7 earthquake that hit Mexico-City.

8 And so giving thought to what kind of equipment you 9 need, and how it should be powered, et cetera, is worth 10 while. Looking at the bridges and saying this one is weak, we 11 won *t count on it is, from my point of view, quite enough with 12 respect to that bridge. Making a note of-it and being sure 13 that it is in mind, that we will go around it'it we need to 14 CCMMISSIONER ZECH: Thank you, Mr. Chairman.

15 COMMISSIONER BERNTHAL: I guess, aside from the 16 interesting discussion, Lando picked-up on the point'that wo 17 ought to try to get to a bottom line on what you are telling 18 us about tornadoes.

19 I guess what we are hearing is that there may have 20 been some-excess consideration, relatively speaking, tor that 21 particular hazard.

22 Let me see also, it I can get a more_ definitive 23 answer perhaps than you care to give on the. issue ot 24 earthquakes 1and their impact on emergency. planning.

25 I t. I made the statement'then that we need'not'be

e s 39 1 concerned or worry about the ettects of earthquakes on 2 emergency planning below the SSE, would you or would you not 3 ' agree with that it you have a seismic event that is of lesser 4 intensity than the safe shutdown earthquake?

5 CH IRMAN PALLADINO: You do make a statement in here 6 that sort of leads you to draw the conclusion that Commissioner 7 Bernthal is drawing. But, go ahead.

8 MR. OKRENT: The analyses that have been done 9 suggests that barring some unknown design error or degradation, 10 the likelihood that a safe shutdown earthquake type will 11 produce a sericus reactor accident appears to be very small 12 And for that reason we did not include that in the group.

13 But, actua21y, as I think aDout wnat one would do e

14 it one followed the ACRS letter, I don't think it matters. I 15 think it is sort of a non-issue, Because what we suggested is le that we consider some earthquakes larger than the safe shut 17 down earthquake, and arrange for communications. Do enough 18 looking around'to anticipate where it could' interfere with 19 your ordinary evacuation routes. Have that information 20 available to whoever it is that would be thinking about 21 evacuation, the sheritt, or.whoever.

22- And so it really doesn't matter.about the SSE.

23 CHAIRMAN PALLADINO: Well, I think it matters in 24 part because of history, which I don *t want to go into.

25 Butfyou do say that the-contemporaneous occurrence l

l I

l

1 8

r 40 1 of such events, implying, cause and e t t e c t'. need not be 2 specifically considered from the standpoint of olisite I

, 3 emergency plar ing. l 4 I am not denying what you said as being true. I

$ just thought it was interesting, in part because of the 6 history of this --

? COMMISSIONER ZECH: May I ask it this -- it the ACRS 8 has then any recommendation to make concerning actions that 9 the Commission should take regarding our current earthquake 10 and emergency planning rulemaking?

11 MR. EBERSOLE: Let me mention something that bothers 12 me.

13 I think we have done a dreactul job of informing the 14 public how these plants work in truth, the media selling 15 sensationalism rather than information. And so I deplore that 16 state of attairs, and wish that the public would understand 17 in case of an earthquake'or a tornado or whatever, they may 19 well expect some loud roars and clouds of steam from the 19 stations which merely come trom station trip out, 20 I can think of.one in.which the populace is routinely 21 excited by the roar of the steam from the boilers. And I think 22 there are quite a few.like that. And I think that this is a 23 -natural consequence of an upset like that.

24 MR. MOELLER: I think'your current approach on the 25 rulemaking is' correct. I think everything you are doing is

j . .a 1 right, l 2 COMMISSIONER ASSELSTINE; Which calls for best Statt 3 recommendations.

' Yes.

4 MR. MOELLER:

5 COMMISSIONER ASSELSTINE: Which calls for site l

i o specific-considerations of the issues, including earthquakes 7 beyond the SSE.

l' 8 MR. MOELLER: Right.

9 COMMISSIONER BERNTHAL: Let me ask one other question i

10 about this point of spatial consideration.

j s.

l 11 You make the point there is a wide variation in i 12 spatial -- Einaudible due.to-coughing] -- and part'of the 13 reason behind the turgid discussion I was trying to have, at 14 least on tornadoes, was that very point. ,

15 Did you really take a careful look at earthquakes in i

16 that context? It is one thing to talk about having an 17 earthquake and assigning a probability let's say to-the 18 earthquake ott Acapulco, wherein,z incidentally, I gather Acapulco was hardly damaged at all, and yet Mexico City with 20 soil liquetaction ~ phenomena, was severely. damaged.200 miles r

21 away. 'Not true?

22 MR. SIESS: There was'no soil.'liquetaction in Mexico 23 City..

24 COMMISSIONER ASSELSTINE: Is that a tact?J 25 MR WARD; Well, it was a phenomena.ot t h e 's o i l '. It

9 ~1 42 1 just wt.sn*t liquefaction.

2 [ Simultaneous discussion..]

' 3 CHAIRMAN PALLADINO: One at a time.

4 Im sorry, I missed what you said.

$ MR. SIESS: I said it was not liquefaction. It was 1

6 simply that the soil natural period happened to be in one that 7 wasn't very compatible with some buildings between ten and 8 twenty stories. That soil didn*t liquety.

9 COMMISSIONER BERNTHAL: I_ guess I am getting bad 10 information. There was a rather long, and I thought very good 11 article, that appeared in " Science News."

12 MR. SIESS: It was a good explanation of I?. liquelaction. But it was wrong.

14 [ Laughter.]

15 COMMISSIONER BERNTHAL: Very good. Good publication.

16 But, back to the point. Did you attempt to look at 4

17 this very, very spotty kind of ettect in the context of 18 earthquakes? As I started to say, it is one thing'to talk 19 about an earthquake and its frequency. But then just as we 20 have done rather carefully tor tornadcas, we really tried to 21 'tocus on how often you are going to hit a certain' area.

22 I don't think anybody has:ever done-that for 23 earthquakes, have they?

24 MR. SIESS: When you get to Eastern U. S., that's 25 our problem. We don't have geological features that we can

1

. c. s 43 l

1 tie to existing earthquake records.

2 COMMISSIONER BERNTHAL: But even in the West. I 3 don't think it has been done anywhere.

4 MR. SIESS: Well, in the West, you know where they

$ are coming from.

6 MR. KERR: Are you talking about likelihood or 7 occurrence, or even it the earthquake has occurred, the area 8 of damage?

9 COMMISSIONER BERNTHAL: Precisely.

10 MR. SIESS: We don *t know much about either one.

11 And the Statt*s approach to seismic design of nuclear plants 12 uses the tectonic province approach. It there have been

, 13 e4rthquakes in the area, and you can't distinguish it from any 14 other area, you assume you could have one about as big as they 15 have had in the past, wherever the area is.

16 And then to get the ground motion for which you 17 design the g-values and so forth, you do take into account t h o' 18 toundation conditions, the local soil conditions. And, back _

19 in the days when we used to plants down on the river bottoms, 20 where everything aad to have-cooling. towers, we had 21 liquefaction p r o b l e,n s . There were.a lot of plants where 22 liquefaction was an iscue, Most of those have gone away now 23 that we are putting them up on the blutt. But,cthose. things 24 are all taken into accouat.

25 But, the thing is Eastern U. S., you are just sort

a

• 44 i of looking at history and just trying to make some reasonable 2 assumptions. That is where that 10 to the minus 3, 10 to the 3 minus 4 comes from.

4 MR. KERR: But, Chet, 11 you assume an earthquake 5 has occurred, say either Charleston or New Madrid, then we 6 have some reasonable evidence on the area of damage. And I

? think this is a question that has been raised.

8 COMMISSIONER BERNTHAL: That*s right.

9 MR. SIESS: The area of damage, it depends on how 10 big the earthquake is, and what is around it.

11 COMMISSIONER BERNTHAL: What I am talking about is 12 not even the area of damage. That is a very, very loose term.

13 What I am asking about is, pick any square mile you 14 like with structures on it. My impression is that we take no 15 credit at all -- and maybe it is because we don't know how to 16 do it --

we take no credit at all for the tact that in that 17 square mile, as Mexico C:ity amply demonstrates, a lot of IB buildings are left standing, and some are knocked down. And 19 that was, of course, a very bad situation.

20 Now, in some sense I suppose it-is taken into 21 account, for example, at Diablo Canyon, because of the fact 22 that the plant is located on rock and presumably very stable 23 toundation.

24 MR. SIESS: I don't know where in the process you-25 would take into account -- the-design of the plant, yes.

a g.

45 1 COMMISSIONER'BERNTHAL: Emergency planning.

2 MR. SIESS: Emergency planning involves bridges, 3 involves roads. It could slide ott a hillside. It involves 4 buildings that~ tall down on people and therefore shelter them.

5 COMMISSIONER BERNTHAL: But with what probability, 6 that is my q u e s t'i o n , for a given bridge. Even given the 7 earthquake.

8 MR. SIESS: Well, we had a report trom the Federal 9- Highway Administration on extensive studies they had made in 13 California after the San Fernando earthquake, which took down 11 a bunch of bridges. They have got bases now for evaluating 12 the seismic capacity of bridges.

13 The thing is, it you get in the Eastarn U. S., take 14 the kind at earthquake we are designing nuclear plants for, 15 there are a lot of bridges that aren't going to do very well, 16 because it wasn*t even considered then.

17 That depends on the type of bridge. It it is just 18 sitting there, it may just bounce. It it is on high piers, it 19 may fall over. That-is the sort of thing that engineers have 20 to do, and there is a kind of study that should be made: .Is 21 that. bridge likely to be damaged by an earthquake, by somebody 22 who knows something about earthquakes and the response of 23 buildings and response of bridges, should look at that.

24 COMMISSIONER BERNTHAL: I guess what'I am trying to 25 drive at, it seems to me it is.not a deterministic phenomenon l

1

,. a 4e 1 entirely -- it is in principal -- analyzing --

a 2 MR. SIESS: You tell me how big an earthquake is and 3 I can tell you a lot closer than a seismologist --

4 COMMISSIONER EEENTHAL: You can analyze a bridge, 5 and it we knew all that we someday may know -- I doubt it 6 about geophysics -- what you really would need to do is 7 analyze the geology and the physics of the geology very 8- carefully, and then you could say something about the 9 probability.

10 Lacking that deterministic capability, it-seems to 11 me the best you can do, tolding in perhaps your engineering 12 knowledge of the bridge -- but I suspect more important right.

13 now is things that have to do with where it sits and the.

14 geology underneath, and --

1b MR. SIESS: The best I could do right now would be 16 to take the response spectrum that the Statt.has specified'for 17 the nuclear plant nearby,-which gives me a spectrum-of g 18 values and frequencies and apply _that to the bridge as a 19 , ground motion or foundation motion. The same way that a 20 nuclear plant is designed. And.I think I would be-reasonably 21 conservative, because I think the response spectra we-use for 22 the plants are-reasonably conservative.

'23 They envelope a lot of regional responses.

l 24 It wouldntt'have covered Mexico City. That is a 25 .special case. )

47 1 And then knowing that input, that seismic ground 2 motion, I could estimate whether that bridge would fall down, 3 a lot closer than geologists could tell me what the earthquake 4 probability is And, I wouldn't have to be very close. It.it 5 looks like it is a problem, I will figure a way to get around 6 it. I am not going to sharpen my pencil 7 COMMISSIONER SERNTHAL: I guess.another way to put 8 it is -- and I will stop here momentarily - is that for a 9 given radius from the epicenter, suppose I have 100 bridges, 10 exactly identical construction. 'Some of those are going to 11 tall down, and some aren*t, I'll bet.

12 And the question is, how many are going to tall 13 down? That is the question we have never asked very carefully, 14 it seems to me.

, 15 MR. SIESS: Well, it I were doing the transportation to planning for evacuation, I would assume most of them.

17 MR. REMICK: Do'you mean how many are going to fall 18 down, or how many are going to see the design basis s p e c t r u m *t -

19- I mean, there'is two ditterent-ettects.

20 COMMISSIONER BERNTHAL: Same question, 1 think. I 21 am assuming the bridges are ~ identical 22 MR. REMICK: You are not worried acout the structure.

23 COMMISSIONER BERNTHAL: 'The bridges'are i'

'dentical.

24 100-identical bridges.

25 MR. REMICK: How many will actually see the, design

48 1 basis spectrum?

2 CCMMISSIONEM EERNTHAL: I am sure they are not all 3 going to fall down, even though.the event has exceeded the 4 design basis. That is my point.

5 MR. SIESS: But they are oriented the same-direction, 6 which is important.

7 Incidentally, if you looked at your bridges from the 8 point of view or earthquake, you have probably covered yourselt 9 very, very well for tornadoes, t

10 If you looked at what might not be there after an 11 earthquake, you have got the same probability. Tornadoes.can 12 take bridges out, too.

13 CHAIMMAN PALLADINO: Even winds can take them out 14 MR. SIESS: Tornadoes can take other things out, It too. .You know, a tornado doesn*t get ignored just because we it -say you don't need to look at tornadoes-specifically. There 17 is not too many places, except for' missiles, that he can do a 18 different kind of damage than an earthquake. They.are both 19 ,

tending to push things.over.

20 CHAIRMAN PALLADINO: Unless there.are other pressing 21 questions on this -- I.know Mr. Remick would like-to make a 22 comment -- after he has made the comment, unless it really

'23 requires a response, why don't we turn to the next topic.

24 MR. WARD: In fact, Mr-. Chairman, we have no urgent i

25 need to cover.the other two topics at this time,'So, 11

a o e 49 1 you would like --

2 CHAIRMAN PALLADINO: I might ask you one question on 3 the other two --

4 MR. HEMICK: I was just going to say that I would 5 get concerned, I guess, 11 I saw this to be a detailed seismic 6 analysis at every bridge. It seems'to me that is a moot point

? because the bridges could be taken out for maintenance. Or it 8 could be that there is an accident on the bridge which would.

9 So, I think the approach has to be for whatever 10 reason, suppose that bridge isn't available, is there an 11 alternate path? You know, that type of thinking, rather than, 12 I would hate to see this be a detailed analysis et all 13 structures, roads, bridges and so torth, ter hypothetical 14 seismic events.

15 COMMISSIONER BERNTHAL: Well, let me ask one 16 question. I guess it may have a short answer,-because I don't 17 think you were asked to do this. -

18- Did you consider whether the standard emergency ,

19 planning that FEMA does, and the consideration of alternate 20 routes that they normally do when they take into account 21 other natural phenomena are adequate then for the earthquake 22 circumstance as well?

23 I'm not sure you were asked to do that.

24 MR. MOELLER: No, we didn*t. But that is a good 25 point.

.. g -- e i e 50 1- COMMISSIONER BERNTHAL: Would'you' presume that they  ?

'2 would be adequate, since what you are really saying is you 3 ought to look at alternate routes and assume certain bridges ,

4 may n o *. be there. i

$ I don't know how tamiliar you are with what FEMA 6 does. They do some of that after all for other phenomena.

- 7 MR. OKRENT: I would assume not, because there could B - be circumstances for some' sites'that lead to, 11 you will, 9 correlated variants or whatever that they would not ordinarily ,

10 put into their thinking.

11 COMMISSIONER ASSELSTINE: I was also going to point 12 out that FEMA did tell us, I think, that they did not, in 13 tact. .And that there would.be some added ettort-that would be- j 14 needed it the Commission were to adopt the rule that provided r

15 comments to us on proposed rules.

i

, 16 MR. KERE: The answer to your question is,1we did

. 17 not look.

18 MR. SIESS: 1 betLthey do it in' California.

19 CHAIRMAN PALLADINO: I am going to suggest we spend 20 two minutes on the next two topics.

4

- 21 With regard tocthe ACRS ettectiveness report, which 22J is one ot'the two topics, I was wondering'whether the ACES

23. plans to'come'up with a recommendation;.what you intend to do

' 24 with regard to the recommendations.

23 MR. WARD: Yes. We are approaching it in a tairly

+ - . , . - . .. .-_ .

f'..'e 51 1 ' disciplined way. Although we have actually adopted a couple 2 of the recommendations so far, we do plan to document a plan, 3 and we will review that with you.

4 In particular, there are some parts of that plan 5 that will involve cooperation with you and we will definitely 6 review those. -

7 CHAIRMAN PALLADINO: Are-you going to write a letter 8 on your plan?

9 MR. WARD: Yes. Some sort of a report, We are 10 probably two months away from doing that, though.

11 CHAIRMAN PALLADINO: Thank you.

12 I read with interest the analysis by your tellows.

13 MR. SIESS: Are any of those recommendations you 14 would particularly like to endorse?

[1 15 CHAIRMAN PALLADINO: It you'had a lie detector on 16 me, 'there would have been times when I had a policy. B u t,, I 17' didn't mark them down.

18 [ Laughter.3

/

19 I was really pleased to have the opportunity to read 20 them.

21 MR. WARD: To make a general comment, I,think in 22 general the committee members are -- maybe enthukiastic is'too 23 strong a word --

but reasonably positive on the general tone.

24 of all the recommendations. Some of them perhaps are sort of 25 obvious. But we are looking torward to adopting many ot-

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33 1 them, and we think they will help our usefulne'ss to you as an 2 advisory body.

3 Mk. EBERSOLE: May I make a comment. I have some 4 problems with; the view that we be almost entirely cosmic in 5 our activities.

6 MM. SIESS: But we were completely agreed on only 7 dea 51ng with cosmic issues, and next year we are going to 8 decide what,. cosmic issues.are.

9 [ Laughter.3 10 CHAIRMAN PALLADINO- One other question on safety 11 goals. Whit is your next step with regard to safety goals.

12 MM. OKHENT: We have had one subcommittee meeting 13 wath the Statt They a s ked' i t we could hold a second a

14 . subcommittee meeting prsorn,to when they-anticipate preparing a 15 memorandum from the EDO to the Commission, and we plan to do 16 that. .

17 The tull Ccmmittee w i l'1 r e v i E w q-- t h e full Committee 18 has been updated on the subcommittee meeting, but they haven't 19 tried to think about ' ma,tters in detail That will occur as 20 soon as the EDO prepares l't s proposed approach.

?

21 CHAIRMAN PALLADhNO: Okay.

2 'J ' ,- Unless there are really burning , questions, I think 23 'maybe we --

i 24 . CONMISSIONEN NNCH: I would like to .thank the 25 ACHS for thei r- res pons e Jto these questions. It has been very P

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2- C'OMMISSIONER ASSELSTINE: Joe, let me just make one l

3 request in connection with the report on ACES ettectiveness.  :

4 The panel came down quite strongly on cosmic issues ,i 5 kind of approach and getting out of the review of each 6 individual license application.

? As you think about that and what you all want 8 particularly in terms of relief from the current requirement 9 under the law, I would just suggest that perhaps you think 10 about what is happening now, trends in licensing, and does 11 1 that in itself provide you the opportunity to spend more time 12 on the other things.

13 MR. WARD: I thank you are right. I think maybe it 14 is a low priority consideration for us.

15 COMMISSIONER ASSELSTINE: I would say in general I 16 thought the panel report was a very thoughttul ettort, a very 17 good ettort by those people. There is a lot of good ideas in 18 it.

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, 19 CHAIRMAN PALLADINO: Thank you-very much, gentlemen.

20 We very much appreciated your coming to visit with us. I think 21 you have certainly enlightened us on'a-number of issues.related 22 to earthquake emergency planning.

23 We look forward to reports and activities on the 24 other two topics.

25 MR. WARD: Thank you, Mr. Chairman.

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. CHAIRMAN'PALLADINO: We stand adjourned.

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s 2 IWhereupon, at 3:20 p.m., the meeting was adjourned.3 3

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9 10 11 12-13 14 15 16 17 '-

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s 1 CERTIFICATE OF OFFIC1AL REPORTER 2

3 4

5 This is to certify that the attached proceedings 6 before the United States Nuclear Regulatory Ccenission in the 7 enatter of- COMMISSION MEETING 8

9 Name of Proceeding: Periodic Meeting with Advisory Council on Reactor Safeguards (Public Meeting)

~10 11 Docket No.-

12 Place: Washington, D. C.

b 13 Date: Thursday, November 7, 1985 14 ,

15 were held as herei.n appears and that this is t_he original 16 transeript thereof for the file of the United States Nuclear 17 Regulatory Commission.

1s , ,

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(Typed Name of Reporter) Mimie Meldzer 20 21 22 23 -Ann Riley 4. Associates, Ltd' .

24 1

25

- ,, bO!f M d C Corrected Copy j

1. h UNITED STATES F $ NUCLEAR REGULATORY COMMISSION i I

$ I ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASmNGTON, D. C. 20556 October 16, 1985 Honorable Nunzio J. Palladino Chairman i U. S. Nuclear Regulatory Connission Washington, D. C. 20555

SUBJECT:

ACRS REPORT ON IMPACTS OF NATURAL PHENOMENA ON OFF-SITE EMERGENCY RESPONSE -

During its 306th meeting, October 10-12, 1985, the Advisory Committee on Reactor Safeguards, in response to the oral requests made by Commis-sioners Asselstine, Bernthal, and Zech during our meeting with the Commission on July 11, 1985, met with the NRC Staff to review and evaluate the relative importance of various natural phenomena which could initiate, or occur in coincidence with, accidents at nuclear power plants and which have the potential for significant impacts on off-site emergency response. The specific matters addressed were:

1. The range of probabilities for the occurrence of various natural phenomena,

2. Their relative potential for causing severe core damage, and

3. Their relative potential for having a significant impact on off-site emergency response.

These matters were also the subject of a joint meeting of our Subcommit-tees on Site Evaluation and Extreme External Phenomena held on October 9, 1985.

Our evaluations were made in the following context:

1. The probability for occurrence, the severity, and the potential contribution of individual natural phenomena to nuclear power plant accidents are site-specific. The potential impact of various natural phenomena on off-site emergency response is also site-specific. For example, although the effects of hurricanes may be an important consideration for plants located in coastal areas, they would not be important for plants located in the Midwest.

Similarly, the effects of blizzards might be a consideration for plants located in the North, but would not be significant for plants located in the Sunbelt. -

2. The capabilities of nuclear power plants to resist the impacts of C

I various natural phenomena cover a wide range. For example, plant 6c\An n rin I-

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s Honorable Nunzio J. Palladino October 16,1985 5

designs to hithstand the impacts of a design basis tornado are basgd on events that may have a probability of occurrence as low as 10-o/yr. Plant designs'to withstand the impacts of earthquakes, on the other hand, are based on events that may have a probability of occurrence of 10-3 to 10-4/yr.

3. Warning times in advance of the impact of natural phenomena vary over a wide range. The arrival time of a hurricane or a tsunami may in some cases be anticipated from tens of hours to several ,

, days, whereas an earthquake nomally occurs without warning. As a  !

result, supplementary precautionary measures that may be taken in l

, preparation for a hurricane are generally not possible in the case l of an earthquake. '

4. There is a wide variation in the spatial impact of natural events.

The extent of the impact of a tornado may- be limited to a small

' area, whereas the impact of a flood, hurricane, or earthquake may be widespread. Although a tornado that strikes a nuclear power plant might have some detrimental effect on the plant itself, the impact on off-site facilities, and particularly on the capabilities for off-site emergency response, might be negligible.

3 In our evaluations, we reviewed SECY 85-283, " Final Amendments to 10 CFR Part 50, Appendix E; Consideration of Earthquakes in Emergency Plan-

ning," dated August 21, 1985 and discussed key issues with our con-sultants and the NRC Staff. As a result of these deliberations, a

, considerable amount of data addressing portions of the three items cited '

i above was assembled. On the basis of our review of this infomation, we j make the following observations:

l

1. Probabilistic Risk Assessments indicate that some natural phenom-ena, such as heavy rains, blizzards, and fog, are not important as accident initiators. 'However, because the occurrence of such phenomena is relatively . frequent compared to the occurrence of other natural events such as earthquakes and tornadoes the poten-tial for their occurrence contemporaneously with a major nuclear i power plant accident due. to some other cause must be - taken into '

consideration in off-site emergency planning. Current regulations recognize this need, and we believe they are adequate.

2. The potential thacts- of those natural phenomena, such as horri-canes, external floods,- and tsunamis, for which warning times can be provided, can be considerably ameliorated by shutting a nuclear power plant down prior to their-arrival. For example, ttis type of precautionary action was taken by the operators of several East Coast nuclear power plants during Hurricane Gloria in September 1985. The wisdom of incorporating requirements for such actions

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'9 Honorable Nunzio J. Palladino -3 October 16, 1985 into the Technical Specifications should continue to be assessed through evaluation of appropriate probabilistic risk assessments on i a plant-specific basis. This could also be done as part of the t

severe accident policy review.

3. At the present time there is some question as to the frequency with which extremely rare, natural phenomena must occur to be considered in off-site emergency planning. We believe that useful guidance on this subject is available in the Standard Review Plan, Section

2.2.3, which provides limitations on off-site- hazards that must be considered in nuclear power plant safety evaluations. For example, i

Section 2.2.3 recomends that o of occurrence greater than 10,y/yr of causing on-site accidents-site even leading to off-site doses in excess of the limits prescribed in 10

[ CFR Part 100 must be taken into consideration.

Based on the above considerations and observations, we offer the follow-i ing recomendations:

1. Our review indicates that, of all natural phenomena, an earthquake is the only event that nomally provides no warning of its in-pending occurrence and that has a significant potential for causing severe core damage and contemporaneous major disruption of off-site emergency response. The peak ground acceleration of an earthquake having this potential, however, is generally considered to be several times the safe shutdown earthquake- and its proba-

} bility for occurrence is low. Nonetheless, because such earth-~ ,

quakes have a finite probability of occurrence, we recommend that  ;

such events receive _ appropriate limited consideration in off-site '

emergency planning. For further discussion on this matter, see our letter to you of June-10,1985.

I i

2. The probability for the contemporaneous occurrence of an earthquake l

that impairs the capabilities for off-site emergency response and a major nuclear power plant accident due to some - other cause is extremely remote. . For this' reason, the contemporaneous occurrence of two such ' events need not be specifically considered from the standpoint of off-site emergency planning.

3. Of secondary importance, compared to earthquakes, are tornadoes, hurricanes, and external floods. Tornadoes are placed in- this category because of their. limited spatial impacts and the conser-vatisms that exist in the designs of nuclesr power plants to resist their impacts. Although hurricanes and external floods are both of concern because of their potential for causing extended disruptions in the - supply of off-site power, the occurrence of these two natural phenomena is preceded, in general, by a warning time of ~

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l hours to days. This fact, coupled with the f. net that nuclear power plants are designed to cope with the impacts of these events, should considerably limit their contributions to severe core damage

. and the associated need to consider their impacts on off-site emergency response.

Sincerely, David A. Ward

. Chairman 3

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$ ,$ ADVISORY COMMITTEE ON REACTOR SAFEGUARDS Q WASHINGTON, D. C. 2(468

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• • "* October 17, 1985 Honorable Nunzio J. Palladino Chairman U. S. Nuclear Regulatory Commission Washington, D. C. 20555

SUBJECT:

ACRS CO M ENTS ON CONSIDERATION OF EARTHQUAXES IN OFF-SITE '

EMERGENCY PLANNING During its 306th meeting, October 10-12, 1985, the Advisory Comittee on Reactor Safeguards continued its review of the Proposed Final Amendments to 10 CFR Part 50, Appendix E, Consideration of Earthquakes in Emergency Planning. The primary document considered in this review was SECY 283, dated August 21, 1985. This topic was also the subject of a joint meeting of our Subcommittees on Site Evaluation and Extreme External Phenomena held on October 9,1985. We had previously written a letter to you on this matter on June 10, 1985.

On the basis of this review, we offer the following additional coments:

1. Al though we realize that the NRC Staff plans to address many classes and types of low frequency natural phenomena in its con-siderations of their complicating effects 'on off-site emergency planning, the ACRS believes that seismic events warrant specific attention. Our reasons for making this recommendation are covered in a separate letter to you dated October 16, 1985, "ACRS Report on Impacts of Natural Phenomena on Off-site Emergency Response."

2. If the Comission desires to address low frequency natural phe-nomena on a generic basis, we would urge that a lower bound be set on the occurrence frequencies for events that must be considered.

Useful guidance on this subject is available in the Standard Review Plan, Section 2.2.3.

3. Although we concur, in general, with the four recomended changes in 10 CFR Part 50, Appendix E, as expressed in SECY-85-283, we ,

believe that implementation of the recomendation for the develop- I ment of a capability for augmenting the staff at a nuclear power  ;

plant under emergency conditions should not occur without con- ,

sideration of the nature and extent of the accident. For example, what should be done if exposure rates in the vicinity of the plant preclude transporting people into the site? We also believe that -

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Honorable Nunzio J. Palladino October 17, 1985 it would be useful for the utility to. supply an appropriately limited study of potential seismically induced effects which are relevant to off-site emergency planning.

We hope you will find these coments helpful.

I Sincerely.

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David A. Ward Chairman i

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