ML20134J302

Transcript of 961106 ACRS Severe Accident Subcommittee Meeting in Rockville,Md.Pp 1-121

ML20134J302
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Issue date:	11/06/1996
From:	Advisory Committee on Reactor Safeguards
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ACRS-T-2081, NUDOCS 9611150142
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Advisory Committee on Reactor Safeguards Severe Accidents Subcommittee TRO4 (ACRS) RETURN ORIGINAL Docket Number: (not applicable) TO sawHITE 1. M/S T-2E26 415-7130 THANKS! j 4 1 Location: Rockville, Maryland l 1 O Date: Wednesday, November 6,1996 i 1 i ) i Work Order No.: NRC-901 Pages 1-121 9611150142 961106 PDR ACRS T-2081 PDR h' O' 1 O b 150002 NEAL R. GROSS AND CO., INC. Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W. i Washington, D.C. 20005 i (202) 234-4433 ( }..:'Ce opy - T.-r,_e _g ~ " q /s. a s 70Te, Ye 0:'te 30mihep

. -... ~,. .. ~. ~. - -. -. - - -.. -......... ~. - -. _. _... i ). i j-1 i l 1 Y i DI.8 CLAIMER 4 PUBLIC NOTICE BY THE i UNITED STATES NUCLEAR REGUIATORY COMMISSION'S i ADVISORY COMMITTEE ON REACTOR SAFEGUARDS I NOVEMBER 6, 1996 3-The contents of this transcript of the j l proceedings of the United States Nuclear Regulatory 1 l Commission's Advisory Committee on Reactor Safeguards on NOVEMBER 6, 1996,_ as -reported herein, is a record of the discussions recorded at the meeting held on the above date. This transcript has not been reviewed, corrected and edited and it may contain inaccuracies. i-l l l i i l i 1 i O 4 3 j NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS j 1323 RHOOE ISLAND AVENUE, NW (202) 234-4433 WASHINGTON, D.C. 20005 (202) 234 4433 .. =,.

1 1 UNITED STATES OF AMERICA 2 NUCLEAR REGULATORY COMMISSION , _.-\\ ( 't.j 3 +++++ 4 ADVISORY COMMITTEE ON REACTOR SAFEGUARD (ACRS) 5 +++++ 6 SUBCOMMITTEE ON SEVERE ACCIDENTS 7 +++++ 8 WEDNESDAY 9 NOVEMBER 6, 1996 10 +++++ 11 ROCKVILLE, MARYLAND 12 +++++ 13 The Subcommittee met at the Nuclear Regulatory f j 'w / 14 Commission, Two White Flint North, Room T2B3, 11545 15 Rockville Pike, at 1:00 p.m., Mario H. Fontana, Chairman, 16 presiding. 17 COMMITTEE MEMBERS: 18 MARIO H. FONTANA, Chairman 19 THOMAS S. KRESS 20 DANA A. POWERS 21 ROBERT L. SEALE 22 WILLIAM J. SHACK 23 24 [(\\) 25 .s_ NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. l (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433 l

........ -. ~,... -. .-.~...._,-.,..~.___..-..; 2 1 ACRS STAFF PRESENT: { l l 2 AMARJIT SINGH O 3 i f 1, -4 ALSO PRESENT: i L 5 KURT COZENS .{ j' 6 RICHARD EMCH 7 JIM GROVER l 8 ANTHONY HUFFERT 9 DAVID E. LEAVER l. i 10 SHERI MAHONEY I h 11 JAMES METCALF l .t t -12 CHARLIE MILLER ~' 13 14 i '15 16 i ) 17 k l J 18 1 19 20 .21 22 23-i l i .24 25' f NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS { 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 - WASHINGTON, D.C. 20005-3701 (202) 234-4433 =.

3 'l A-G-E-N-D-A 2 -Acenda Item P_ggg .3 Introduction-4 4 Proposed SECY Paper 5 5 Grand' Gulf License Application 46 6 EPRI' Report' 58 7 ACRS Discussion 3 9 10' 11 12 13 ] l 14 15 16 ' 17. E 18 .19 I

20 l -

21 22 23 24 '25 i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 1

4 1 P-R-O-C-E-E-D-I-N-G-S 2 (1:01 p.m.) ,3 i 3 CHAIRMAN FONTANA: The meeting will now come 4 to order. This is a meeting of the ACRS Subcommittee on 5 Severe Accidents. I am Mario Fontana, Chairman of the 6 Subcommittee. The ACRS members in attendance are: Thomas 7 Kress, Dana Powers, Robert Seale, and Bill Shack. 8 The purpose of this meeting is to gather l 9 information on tht proposed SECY paper concerning the 10 approval of license applications using a revised source 11 term at operating reactors. The Subcommittee will hear i 12 from representatives of: the NRC staff; the Nuclear 13 Energy Institute, NEI; and Energy Operations, Inc.

n

'w. 14 concerning this issue. j 15 Amarjit, Jit, Singh is the cognizant ACRS 16 staff engineer for this meeting. 17 The rules for participation in toady's meeting 18 have been announced as part of the notice of this meeting 19 previously published in the Federal Register on October 20 21, 1996. 21 A transcript of the meeting is being kept and 22 will be made available as stated in the Federal Register l 23 notice. It is requested that the speakers first identify 24 themselves and speak with sufficient clarity and volume so 7(,) 25 that they can be readily heard. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

. ~... 5 l 1 We have received no written comments or I 2 requests for time to make oral statements from members of ~ -3 the public. .I 4 We will proceed with the meeting. And I call i ) 5 on Mr. Emch of NRR to begin. 6 (Slide) '7 MR. EMCH: Good afternoon. I'm' Rich Emch. i 8 I'm the Section Chief of the Radiation Protection Section 9 of the Nuclear Reactor Regulation. I will be making a ~10-presentation this' morning. 11 With me are: Charlie Miller, Chief of the-12 Emergency Preparedness and Radiation Protection Branch; 13 and Tony Huffert, who has been one of the key staff '(3 ,. v/ 14 members working under my group on this source term and.the j 15 implementation, the plans, our plans for this -I 16 implementation. .There are other people here from the 17 staff representing RES. And I believe there may be one or l 18 two people from our task force from NRR. 19 This is a fairly far-reaching issue. And so l l 20 within the staff, we have had to put together a task force i> j ' 21 of a sort of a multidisciplinary task force to help us 22 deal with this issue. 23 So my main area is accident analysis, 24 radiation protection, the dose analysis part of DBAs, but -25 'I'11 be saying a few words about other things. And, where NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS L. 1323 RHODE ISLAND AVE N.W. l (202) 234-4433 WASHINGTON, D.C. 20006-3701 (202) 234-4433

m. _m t 6 l 1 necessary, I'll get some help from the table to answer any j j 2 questions you my have. 3 3 One thing probably worth noting here-is that RF there is a commission paper that is being prepared -- 5 you'll see it at the bottom -- to go to the Commission. l 6 It was' originally going to be at the Commission before we i 7 had this meeting, that we thought the day.was set such l l 8 that we weren't going to be able to have time to come to i 9 the ACRS before the Commission paper went to the 10 Commission. 11 We have had some last minute negotiations to 12 figure out. exactly what the Commission paper should say. 13 And because of that, the. commission paper.hasn't gone yet, 14 but it's also not in a form, unfortunately, that I was 15-able to'give you a draft today. 16 As I recall, we gave you a draft several weeks 17 ago, Jit. Okay. I would caution you that there have been 18-fairly substantial changes in it since that draft. So 19 don't pay too much attention to especially the part of 20 that draft that talks about staff plans. We've had a lot i 21 of discussions and a fair amount of changes since that 22 draft. 23 Even though I can't give you a draft today, 24-what I will be talking about is part and parcel of what l( ) 25 that Commission paper says, the draft says now. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 .~.

..__..._...._m 7 .1 My. understanding is we're not requesting a i l 4 i 2 letter from the ACRS. However,.certainly if you folks O -3 after hearing the presentations, if you folks feel that 4 you need to write such a letter,_that's your prerogative. 5 We find the reason for the presentation today lo 6 _- is to inform you. Some of you folks'have done work in a 7 some of-these areas. And, therefore, it would be our 8 expectation that you might be'able to give us-a few 9 pointers somewhere along'the way here'. So I'd be happy to i f 10 hear those, too. . 11 (Slide) 12 MR. EMCH: Actually, there's a lot of history 'l 13 that goes to'this. Way back in 1962 the TID source term j. .D 'V 14 was developed. 'We have been using that source term ever - 15 since. There-has been a lot of research and a' lot of 16 analytical evaluations that have been done along the'way. 17 And the result-of all of:that was a new source term, I i [ 18 NUREG-1465, that was issued in February of '95. j I . 19 Both'the industry and the NRC immediately 20 recognized that this was something that the industry L 21 probably would want to make use of. And so we asked the 1 22 industry to handle.it in a generic fashion-so that the NRC 4 23 could review 5 or 6 or maybe a dozen applications that 24 would, then, be generic and be applicable to a number of 25 plants, instead of us trying to do like 3,000 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

8 l l~ 'l plant-specific amendments. 2 In response to that, NEI developed the generic i ,c l' b, 3. framework document. You'll note later on it's designated i L 4 as GFD. But, anyway, generic framework document. And l ? 5-they submitted that in November of '95. 6 Since then, along the way, we have held a l l 7 number of meetings to talk about-what'their submittal was j l 8 going to look like,.what the NRC had in mind. 'And we just l I j 9 recently briefed CRGR last month on the staff's plans.- ') l. 10 And, as it indicates there, we-will be sending a 11 Commission' paper forward soon. l ) i 12 CHAIRMAN FONTANA: Can you tell us what CRGR j 13 thought or is that any of our business? Well,. don't_ ~! i \\ 14 poison our opinion. l 15 MR. EMCH: That's all-right. There's not a- -16 whole lot to tell you, actually. There isn't anything in j i 17 the' slides about.what CRGR said. Actually, I thought it 18 was pretty positive. 19 They quickly recognized that the real fun, so l 20 to speak, will be in the details, which we will deal with 21= as we go through the pilot plants. And so they said, you j 22 know, at some point they want to revisit this. But I 23 thought it was. pretty positive in that they really didn't 24 redirect us. i 25 Charlie, is that your sense? NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS ) 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

_=___._ .___.---.._~.m-t 9 l l 'l MR. MILLER: This is Charlie Miller from NRR. i 2 I think what we found was that at the time we O 3-made this presentation to the CRGR, they were very { 4 interested in the subject as an informational briefing, j i 5 As Rich said, what they're really interested to see.is l 6 what comes out the other end and what's proposed to coue j l 7 out of the other end. 8 And I think at that time they will really in i 9 accordance with their charter be-interested in how we plan 10 on implementa..'c cual. st more than one plant. l t 11 -CHAIRMAN FUNTANA: 'Thanks. l 12 (Slide) 13' MR. EMCH: Okay. This will begin our summary ] . N r/ i 14 of our' review. The objective of the document was to -15 establish aa generic methodology for applying the revised '16 source term at operating plants. 17 NEI in.this document gave us four 18 classifications or categories of plant changes that they .19 ' would expect their members to use or to be interested in. 20 And they also developed four principles that'would be the ~21 guiding light, so to speak, for the use of.this new' source i 22 term. 23 (Slide) if 24 MR. EMCH: We'11 quickly show you first the 25 kinds of. things they want to do with it. I've always NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

10 i 1 found in the past that scientists and engineers want to { l 2 know: 'What's this going to be used for? So we'll flap ) O 3. that up there first. Okay? -j 4 The four categories, allowable leak rate .l t 5: changes. This would be containment leak rates or changes i 6 in leak rates for penetrations. j i 7 Isolation valve timing changes. This is'the j 8 closure times'; for instance, how fast main steam line 9 isolation valves or containment isolation valves would 10 need to be closed. 11 Filtration unit simplification. That's a code 12 word'for take out the filters. They're charcoal and HEPA 13 filtration units for the control room and for some of the 14 ESF systems. 15 And last of all is mitigation system actuation 16 timing. An example of that is a number of plants have '17 standby gas treatment systems or they may call them 18 something else that they use to draw a partial vacuum or 19 negative pressure on a secondary containment, for 20' instance. 'l l j -21 And'it's been suggested that with the new i 22-source term, those systems wouldn't have to draw -- the 23 requirement that they draw down in 15 minutes or something 24 like that could be relaxed because with the new source f 25 term, there's going to be -- you know, the stuff will be l NEAL R. GROSS l-COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

. ~ 11 1 later arriving. And so those are the kinds of things that 2 have been. suggested. 3' MEMBER POWERS: The 1465 source term, as I 4 recall, describes the.radionuclide inventory arriving in 5 containment but does not say anything about subsequent I -6 happenings to that radionuclide material. 7 So when you think about applicatiors of the .i 8 classes that you have listed up there, several of them 9 have to do with what'the radioactive material looks like .10 in containment after some protracted period of time. How 11 do you address that? 12 MR. EMCH: Okay. First off, while 1465 didn't .I 13' give a lot'of specifics, it did have a section that talked '} 1 / 14 about some'of the removal mechanisms that would be 15 available in containment, but it didn't really pin 16 anything down. It just said, "Here are some of the things 17 that'are available." 18 Beyond that, we would use calculational 19 methodologies, which I'm going to talk a little bit about i L '20 later on, at least in a simplistic view. But those 21 calculational methodologies will have to assess how much 22 of the radionuclide,'what removal mechanisms are j i 23 available, either from' passive, natural, you know, like 24 gravitational settling or spray systems or filtration l) 25 systems or whatever. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433 L- ~_

12 1 And so the_ collocation, the modeling has to ba 2-done and included in our programs. gl 3 MEMBER POWERS: I was thinking more in-terms i 4 -- those things are all important that you mention. i 5 MR. EMCH: Yes. i 6 MEMBER POWERS: I was thinking more in terms, 7 however, of iodine partitioning out of aqueous solution l t 8 into the atmosphere as organic iodide, possibility of. l l 9 tellurium doing the same thing, possibility of ruthenium l 10-doing that. j i 11 MR. EMCH: The chemistry and pH control issue i 12 there. l 13 MEMBER KRESS: Particularly with respect to -l l P s 14 the filtration unit simplification issue, I think. I -15 MEMBER POWERS: Or leakage. i 16 MEMBER KRESS: Or the leakage rate, too. } 17 MEMBER POWERS: It's another one where that's l l + 18 possible'.

19 MR. EMCH:

Yes. The issue of chemistry l l I 20 control, pH control is definitely a part of this l l [ 21 evaluation. As you pointed out, one of the changes here J 22 i is that, whereas in TID it was assumed to be mostly i L 23 elemental, now it will be mostly particulate, although I 24 there still is elemental and organic in the source term. j .() 25 And, well, you know, for instance, just on the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 2344433 ~m_-

13 1 surface, that might suggest that maybe the charcoal 2 filters aren't as important as we used to think they were. --) / 3 Maybe the HEPA filter is more important. l 4 (Slide) 5 MR. EMCH: Okay. The four principles. 6 Principle Number 1 paraphrased is that essentially the 7 existing licensing basis of a plant is acceptable. In 8 other words, the licensing basis that was the calculations 9 that were done using the TID source term and that were 10 reviewed by the NPC, in some cases many years ago, for the 11 plant are still acceptable. 12 And the NRC agrees with that. We have said 13 that there is no safety need, no safety reason to go back ( ); 14 and make people reanalyze using the new source term. So 15 backfitting is not required. The analyses that were done 16 with the TID are sufficient, are acceptable, are adequate. 17 MEMBER KRESS: And you base that conclusion on 18 what? 19 MR. EMCH: One of the things that we have 20 done, we have had a fair amount of opportunity to do some 21 examination of this because we have been using the new 22 source term, various forms of it, on the advanced plants, 23 CE 80 plus the AP600. And along the way we've done some 24 other kinds of calculations, some looking at regular power (G 4 25 plants. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

-. _,. _. - ~... -.. - -1

14 4

1 And I think pretty much our conclusion is that 2 if you -- I'm going to talk in a moment about old O 3 framework or current framework and new framework. But 4 just for a moment, if you take the TID source term and you 5 do the calculations with a-current framework, the current 1 6 criteria, the current calculational methods, and you get a 7 dose or a set of doses and you turn around and look at 8 that same. design with a new source term, a revised source L 9 term, the calculational methods that we think are most! i l_ 10 appropriate.to go with that and with the criteria, the 25 I' 11 TEDE' criteria, all the calculations we did showed if it -12 met the old way, it will meet the new way. That's really 13 the underlying basis for that statement. l '14 MEMBER KRESS: I didn't interpret that -i 15 principle to have anything to do with the new source term. I 16 I. interpreted that to mean that we're licensed with what 17 we've got. Therefore, we're not required to use the new 18 source term or to change anything because of the new i 19 source term. 20 MR. EMCH: That's correct. I interpreted your 21 question as being: Why do you think that's okay 22 technically? That's what I was trying to answer. 23 MEMBER KRESS: .Yes. I guess my question was I 24 can't possibly see that there would be any argument about . b g 25 that. And I didn't even know why it was brought up in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

h 15 t 1 first' place. i 2 MR. EMCH: There hasn't been. 3 MEMBER KRESS: Yes. 4 MR. EMCH: There hasn't been. There hasn't j i 5 been any argument about it. 6 . MEMBER KRESS: Unless we suddenly discovered j i 1 7 by the.new knowledge that the existing licensing basis'was 1 8 unsafe. 9-MR. EMCH: Right. It.would take something 10. pretty -- 11 MEMBER KRESS: It would take -- 12 MR. EMCH: -- a pretty substantial surprising i l 13 finding to move away from that, yes. I think you might s . s 14 ask: Why'is it'even up there? I think it was NEI was ] 15 attempting to really baseline where are we at on this j 16 subject, and I think they felt 17 MEMBER KRESS: Okay. '18 MR. EMCH: -- it was important to.say -- 19 MEMBER KRESS: It was important to say that. 20 MR. EMCH: " Don't anybody go jump off a j j 21-bridge. What we've got is okay." 22 MEMBER KRESS: If they want to keep it that i 23 way, fine. 24 MR. EMCH: What that means is and what we 25 understand is there are probably a number of utilities. i l NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS I 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

16 i 1 I've talked to a number of utilities who say, "I like my 2 licensing basis, my design basis just fine. I don't see 3 that that -- I don't have anything that I want to use that 4 new source term to do. So it will be years before I even [ 5 think about it." And that's perfectly okay. 6 Principle Number 2, complete implementation of 7 the new source term as a substitute for the' existing 8 licensing basis is acceptable. Just simply that. NEI 9 says, "Okay. If you could use the old one, now.we can put a 10 the new one in and do the calculations. And that should 11 be okay. 12 And I think the NRC generally agrees with that 13 concept, although a couple of things that we need to \\-- 14 mention is: first off, we believe that if you're going to 'l 15 use the new source term, you need to do an' integrated j 16 assessment. 17. MEMBER KRESS: What does that mean? 18 MR. EMCH: Okay. I have some stuff later, but i 19 let me try it now. Okay. What we'say by integrated 20 assessment is, instead of just saying, "Okay. I'm going l 21-to take this piece of equipment out of the plant" or 1 22 whatever and it affects the DBA doses for the LOCA this i l 23 way, our belief is that there may be more to it than that. 24-Yes, there are effects on the LOCA dose, but there may () 25 also be effects from that on other design bases analyses NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 1 i

17 1-that may have nothing to do with dose. Okay. 2 A quick example: Containment isolation valve O 3 closure times. Very first time we looked at that, we 4-thought, "Well, you know, that's pretty much a dose issue. l 5 You can go from 5 seconds to 15 or 30 or whatever it is. 6 And'it probably won't make much difference in terms of the 7 dose with a new source term because of the timing of the 8 phases." 9-A little bit closer analysis or a little bit 10 closer look said, "Well, you know, there are other things 11 that come into play here. There's the issue of whether 12 the valve could close against the pressure if you wait a 13 while. There are issues of whether debris would'h ng up D\\d 14 the valve coming into play so that you wouldn't be able to 15 close later on. There's a back pressure that comes into 16 play for the ECCS requirements." 17 So, as an example, we saw, hey, it's not just 18 a simple matter of put a new source term in and calculate ] 19 a new dose. There are other things that come into play. 20 And one -- 21 MEMBER KRESS: That's what you mean by an -22 integrated assessment. 23' MR. EMCH: Right. And one of the most 24 important things there is especially, which leads into the 25 second one, when you start talking about taking out a NEAL R. GROSS e: COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. i (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 4

l l' 18 l 1-piece of equipment that used to be in the plant; for 2 instance, filter trains, and saying it's just not going to l l, O L L 3 be there anymore. j l .4 That has a very definite effect in terms of l 5 the DBA dose calculations, but we ask ourselves, we need I l 6 to'ask ourselves: Okay. It was part of the l-7 defense-in-depth that made this plant a robust safety 8 analysis for the staff. -9 And so that when-the staff. started asking y i 10 questions about severe accidents, it provided part of that 11 robustness that allowed us to say we think that that's i 12 pretty well.taken care of. Okay. We think severe i 13 accidents are not a big issue. f 14 And so if you go into this and you say, "Take i 15 out'something that we used to regard as part.of'that,. as j t [ 16 defense-in-depth," now we need to ask ourselves: Is the l l -17 design still as robust to handle challenges like severe l 18 accidents, severe accident challenges? 19 MEMBER KRESS: So you don't think this I 20 question of the source terms needs to be limited to design 21 basis space? Somewhere in there you ought to think about -l 22 severe accidents? [ 23 MR. EMCH: No. As a matter of fact

yes, i

r. -24 that's very definitely a position by NRR management that l 25 we need to make sure that we haven't removed any of the i.- NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE, N.W. l (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

19 1 real safety margin associated with a plant's ability to 7~ 2 handle severe accident challenges. i ) \\ 3 (Slide) 4 MR. EMCH: Third principle. Yes? l 5 MEMBER KRESS: Sorry. I guess I missed on 6 Principle 2. Did you say in general the staff is in 7 agreement with that principle? 8 MR. EMCH: Yes. It's probably worthwhile for 9 me to state right now we're in general agreement with all 10 four principles. Okay? 11 MEMBER KRESS: Okay. 12 MR. EMCH: There are concerns that we have. 13 And I'll express them, just as I have here. But in 7 s, i ) i_/ 14 general we're okay with the principles. 15 Okay. Selective implementation, Principle 3. 1 16 Industry felt that selective implementation; in other 17 words, only using the new source term for certain kinds or 18 parts of the analyses, should be acceptable as long as it 19 was shown to make sense, I guess is a r,imple -- I don't 20 remember the exact words, but that's pretty close. As 21 long as it was shown to make sense, they felt that 22 selective implementation should be allowed. Okay? 23 of all of them, this is probably certainly one 24 of the places where the staff has felt the most uneasy. p. ( ) 25 We, for instance, thought at one point there are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

20 1 discussions about there are timing-only applicationc. 2 There are chemical form-only applications. 73 ( ) x '- 3 Let's talk about timing only for a moment. We 4 thought at one point that the containment isolation valve 5 closure time was an example of something that might be a 6 timing-only application, that it might be something where 7 you wouldn't even need to do dose calculations. You might 8 just be able to say, "Just based on the insights of the 9 new source term, it's at least 30 seconds before the gap 10 phase shows up." Okay? And so if it hasn't shown up, 11 then you ought to be able to use just on an insight -- you 12 wouldn't even need to do a dose calculation, just say, "As 13 long as the time frame is less than 30 seconds, it should I h 14 be okay." All right? I'll use that as an example of a 15 timing-only application. As I pointed out earlier, it 16 didn't turn out to be quite that simple. Okay? 17 So I guess it's our belief that it is possible 18 that we can have some Felective implementation of 19 timing-only applications. When we start to look at some 20 of the other selective implementation, like a chemical 21 form only, we're less enamored with that idea. 22 We believe that, really, once you get to the 23 point where you have to do dose calculations to approve 24 the change, that you really need to use the entire revised (, () 25 source term. We don't believe you can just go in and just NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. i (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433 l

-. -. ~.. -. - - -.. _, .21 1 put the chennical nature -- you know, just say, "okay. .2 Well, now: iodine is in this form, instead of this form." O -3 We believe that we'need to do a more complete calculation 4 and look and' assess the integrated impact. 5 MEMBER KRESS: Design basis accident? 6 MR. EMCH: Yes. But, as I pointed out before, 7 integrated impact won't just be design basis. It will 8 look to see if there are impacts in other areas as well, 9 severe accidents, equipment qualification,~whatever. 10 Okay. Principle Number 4, the dose 11 calculacions based on the existing methods and limits are 12 acceptable. And-what they really mean by that is if~you 13 take the current. methodology, -- you know, that's the 14 framework, the TID, and the current limits, the 25 rem 15 whole body and 300 rem thyroid -- if you just substitute. 16 the new source term for the old one in that calculational 17 framework and then you could do your calculations and see 18 if it' matches up to the current criterion,.that should be 19 acceptable. 20 For a number of reasons, the two most 21 important reasons that we're not sure about that is the 22 TEDE dose, the concept of the TEDE methodology; and the 23 issue of which two hours you're going to do the 24 calculation for the exclusionary boundary. 25 We believe that the whole framework -- how i l NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N.W. l (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

22 j l l 1 much further is the framework slide? Maybe I'll just go l l 2 to that. 'Okay. l 3 MEMBER KRESS: Let me ask you about this. l 4 MR. EMCH: Yes.

l l

t l 5 ' MEMBER KRESS: It's my impression that dose 6 calculation only affects the leakage rate. Am I right?. 1 I l _ 7 MR. EMCH: only affects the leakage rate. l 8 MEMBER KRESS: A bad leakage. l 9 MR. EMCH: I'm not following you, sir. i I i 10 MEMBER KRESS: 10 CFR 100 type calculation -l 11-using these acceptable doses of 25 rem -- l .12 MR. EMCH: Right. l l l 13 MEMBER KRESS: -- on every source term. What i I O-14 that does is fixes your leak rate that you're allowed to i 15 have following containment. 16 MR. EMCH: That's certainly one of the things 17-that it does, yes, 18 MEMBER KRESS: My impression was it was the 19 only thing. 20 MR. EMCH: Okay. It does that. Also, it 21 comes into play as to the capability of ESF systems, like 22 filters and things like that. 23 MEMBER KRESS: They get involved in the l 24 calculation, right. I 25 MR. EMCH: Yes. Okay. Right. t NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 ' WASHINGTON, D.C. 20005-3701 (202) 234M33

23 1 MEMBER KRESS: If it were an existing plant, 2 all those things are fixed. ,s ( ) 3 MR. EMCH: Initially they would be, but one of 4 the things -- let's stop and ask yourself: Why would an 5 operating plant want to pick this thing up and use it? 6 And the answer that I keep coming up with is the only 7 reason that they would have for going through all the 8 revised calculations and everything is to make some 9 changes. Right. Okay. 10 So if they make some changes, then you get 11 into: Well, what does it impact? 12 MEMBER KRESS: They're not going to change ) 13 their sprays. Ks/ 14 MR. EMCH: We hope not. Okay. We don't 15 believe that that will happen. In my staff's worst 16 moments -- 17 MEMBER KRESS: So I still maintain if they 18 don't change their sprays, the only thing this calculation 19 does is affect leak rate. 20 MR. EMCH: Okay. That's one of the things. 21 If you remember the slide that I put up with the four 22 categories, timing of valve closure, timing of system 23 starting, and coming on line, there are other places that 24 it can come into play. Probably leakage -- ( ) 25 MEMBER KRESS: Yes, there is a valve closure c w/ NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234 4 433

24 1 time, but mostly this is just leakage, which I think hus 2 very little risk impact. (. sI ~' 3 MR. EMCH: That's my understanding, yes, sir, 4 that small and even -- well, I have to be careful. I'm a 5 little out'of my area. 6 Certainly small changes in the leakage have 7 virtually no impact on the risk. That's what I understand 8 from the risk folks who are involved with this. And I 9 think that was a conclusion that was drawn in the changes 10 to Appendix J that were -- 11 MEMBER KRESS: Yes. That was part of Appendix 12 J. 13 Okay. I just wanted to be sure I was thinking i .k / 14 correctly when I was thinking about this principle. Thank 15 you for -- 16 MR. EMCH: I'll come back to this in a moment 17 if we need to. Let's go to the framework, to the issue of 18 frameworks. 19 MEMBER POWERS: Can I interrupt you and take l 20 you back? l l 21 MR. EMCH: Yes, sure. 22 MEMBER POWERS: You said that your first 23 principle was the current licensing basis is adequate. 24 Does that include equipment qualification? rx ) 25 MR. EMCH: Yes. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

. _ _ _ _ _ _ _ _ _. _ _ _ _ _. - -.. ~. _. 25 l Y I 1 MEMBER POWERS: If it's qualified under a TID j t [ O.' 3-MR. EMCH: Yes. 2 source term, then it's qualified under.this? l i i l 4-MEMBER ~ POWERS: That's interesting. l 5 MR. EMCH: Well, I gave you the quick pad I l 6 answer. There are others. Certainly I believe that there i 7 has been some investigation of that. I believe there.was l -8 a'SECY paper that specifically talked about that and made [ t i 9 some estimates about what the possible impact in'that area 10' could be. I 11 And I think the conclusion was drawn that .1 12 while the new source term because r,f the' chemical nature 13" and all that might indeed raise the dose in some ,d 14 instance's, that it was felt that the bounds were good '15 enough that we wouldn't have to do anything there. That's r l' '16 the longer answer. 17 CHAIRMAN FONTANA: Going back to' Principle 18-Number-2, you have an item-there, " removal of accident 19 mitigation hardware." j i 20 MR. EMCH: Yes. 21 CHAIRMAN FONTANA: And presumably you agree 22 with this principle. But I remember reading somewhere-1 23 here, which I can't find right now, that a statement was i L l 24 made that the staff would not allow removal of, I think it 25 was, charcoal filters because'it wanted to maintain NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 23H433

- - -. ~ ~ - - ( 26 .j l l- -1 defense-in-depth. i L 2 MR. EMCH: Right. O 3 CHAIRMAN'FONTANA: What's the difference l 4 between that statement and this one that says that I 5 MR. EMCH: It doesn't seem to make sense to l' -6 you, does it? Okay. You remember I said you probably saw 7 that when you were reading the draft Commission paper that 8 we did give.you to you several weeks ago. 9' CHAIRMAN FONTANA: Oh, okay. That's old. 10 MR. EMCH: That's one of the areas where l '11 there's been some adjustment in our thinking. l l 12 CHAIRMAN FONTANA: Okay. 13 MR. EMCH: I think the current one still says j I' ~14 that we are reluctant because of the issue of j 15 defense-in-depth, although it leaves the door open that '16 with proper analyses, a conclusion.could be drawn that it 17 might be that there are some things that could be done I 18 here. 19 CHAIRMAN FONTANA: Okay. Thanks. 20 MR. EMCH: Where was I? I'm going to finally a 21. make it to the frameworks. Okay. 22-(Slide) -23 MR. EMCH: Start off by saying that current I 24 Part 100 does not specify a source term. Okay? If you go l i l 25 to Part 100 and read it, you will find in a -- I forget NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE, N.W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

27 .I 1 how the lawyers say this. It's a footnote, I believe, or j 2-a note that mentions the. TID source term. And, in fact -- I 3 CHAIRMAN FONTANA: By reference. 4 MR. EMCH: Right. All of this: stuf f was j i 5 bubbling to the surface at about the same time in the old. l _6 AEC. ~And the criteria and the calculational methods, the i 7 Part 100 framework, so to speak, really was designed 8 around the TID source term. Okay? 9 The TID source term is everything is-l 10 immediately released. You know, 50 percent of the iodines l 11 and 100 percent'of the noble. gases and 1 percent of the i 12 solids and all of that are immediately released from the-13 core to the containment atmosphere at t equals ~zero-14 seconds. Okay? i-15 And then the Part 100 talks about.doing the 16 calculation over the next 2-hours for the exclusionary 17 boundary. So it's the first two hours. And then there 18-are criteria that are expressed in terms of whole body and l 19 thyroid dose criteria. 20 All of that is wrapped. It all kind of comes l 21 together. It's a framework. The way the staff actually 22 does the calculations, for the whole body dose, we look at 23 the noble gases. For the thyroid dose, we look at the 24 ~ iodines.

• (~N

(,) 25 Very early on, many years ago, a decision was NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 2344 433

28 -l 1 made not to include the one percent of solids. I'm sure 2 there was a number of considerations. It was felt that. i 3 that would make a'small difference in the doses, 4 especially the whole body and thyroid doses. And it was I i s' going to complicate the calculation greatly. 'I .t l 6 MEMBER KRESS: And since you're in design l 7 basis space, why, it's appropriate to not have to include l 5 l 8 things ~like that if you think you're scoping'the thing o L 9 anyway. 10 MR. EMCH: Oh, yes, yes. The staff made--- 11 MEMBER KRESS: You don't have to get all'the 12

details, j

13' MR. EMCH: Yes. The staff drew conclusions i l I l 14 about.how they were going to use this thing and make an' 15 appropriate design basis. And that's one of the-16 conclusions they made. Okay. l l 17 Sothbt'sthecurrentframework. It' includes i 18_ all kinds of things like I said 50 percent of the iodine 19 comes out of the core. Fifty percent of that is assumed I-20 to plate out immediately so that you're really only l 21 working at t equals zero with 25 percent of the iodine. l 22' And there's just lots of -- the whole thing is put i 23 together around, designed around the TID source term. 24 (Slide) 25 MR. EMCH: Now we're talking about the revised NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS ( 1323 RHoDE ISLAND AVE., N.W. [ _. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 2344433

l. l 29

1 source term, where the releases come out in phases.- And 2.

there's a time lag,'the time frame. It's not t equals (:) 3-zero. .It's over a couple of hours or a few hours. 4 And the revisions, I'll say the proposed 5 revisions, the Commission has approved issuance of revised l 6 Parts 50 and 100-for new plants,.but it hasn't actually I L 7. been published yet. So we still have to call it proposed. j 8 Okay? i l; 9 But the revised proposals were really based 10 on, designed around the revised source term. Now,-that I 11 doesn't mean that they can't -- you know, this time ~we-12 thought we'd.try to be a little smarter and say,'"Okay. 13 What about if.there were some other. proposals for source. 14. terms?" 15 And ve tried to include that in'here. But 16 this rule really was developed'to be consistent with the-i- 17 revised source term. And some of the ways that that shows 18 up.is in the'any or worst two hours. 19-Now it doesn't make as much sense to do the 20 first two hours if the worst of the releases may happen j-L R21 later on sort of thing. And, also, that revised rule i i 22 brought forth the concept of the TEDE dosa methodology for 23 accident purposes. 24 TEDE had already been put into place for () -25 occupational doses in Part 20, but this revision to Parts NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 {

30 1 50 and 100 put it into place for accidents, brought the 2 subject forward to use TEDE doses for accidents. And it ,m i \\ r i 3' sets a criterion of 25 rem TEDE. 4 We're going to come back to this from time to 5 time, the two frameworks: the old framework set up to go 6 along with the TID and a new framework that is set up to 7 go along with the way 1465 describes it, the revised 8 source term. 9 MEMBER KRESS: We wrote a letter on the new 10 framework essentially agreeing with it completely. 11 MR. EMCH: Yes. Yes, that's correct. I think 12 you did ask us a question about the dose factors 13 associated with the TEDE. ,e(.) 14 MEMBER KRESS: Yes, we had some problems with 15 that. 16 MR. EMCH: Right. Okay. I think we got that 17 18 MEMBER KRESS: In principle we agreed with -- 19 MR. EMCH: I think we got that straightened 20 out. Okay. So back -- 21 MEMBER POWERS: Are you going to explain that 22 to us? 23 MR. EMCH: Pardon? 24 MEMBER POWERS: Are you going to explain that (j) 25 to us again? NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE.. N W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 l l

'31 1 MR. EMCH: I wasn't planning to. Please don't ';L make me explain that again. O, -3 MEMBER POWERS: .I definitely will not ask you 4 to do it today, but would you sometime? .5 MEMBER SEALE: :And what you did last time 6 wasn't an awful lot of help. So that's not a good place. '7 to start from. 8 MR. EMCH: Okay. This might not be a good -9 time to suggest that it wasn't me doing the talking last-10 time. 11 Okay. So back to Principle 4 for just a: 12 moment, remembering the two frameworks. Our initial 13 reaction to Principle 4 was: Hey, if you're going to use \\_/ 14 the new source term, we need to use this framework. Okay? 15 So our' initial reaction was that we didn't think it would 16 be acceptable-to simply slip the new source term into this 17 framework. 18 Now, after a little more looking at it, a 19 little more thinking about it, some of the things that the 20 industry has suggested to us, we're of the belief now that 21 we're going to use this rebaselining that I'm going to 22-talk about in a few minutes to help us figure out whether 23 it really makes any difference or not. Okay? (. 24 It may be for the advanced plants, it seemed

. f]

25 to make some difference because they didn't have spray

( y-I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4 33 i t

32 1 systems and things like that. For a current plant that 2 has a spray system, for instance, first and worst two ,3 ( l 3 hours, the doses will essentially be the same. So we're 4 going to be looking to see. It may be possible to be 5 completely agreed with the Principle 4. We just have to 6 find out in the rebaselining. 7 We'll get to rebaselining in just a second. I 8 need to talk for just a moment about rulemaking and 9 exemptions, about the possible need for them. 10 (Slide) 11 MR. EMCH: I mentioned that one of the things 12 about the revised source term is the phased timing of the 13 releases. And I also mentioned for the advanced plants x_) 14 that we have looked at the calculation on a worst or any 15 two hours, as opposed to the first two hours. 16 If it was decided that it made a difference 17 for operating plants and that we really did need to do 18 worst 2 hours or any 2 hours, as opposed to the first 2 19 hours, one of the places, one of the things that hangs us 20 up there is the words of the existing Part 100 that talk 21 about doing the dose evaluation for the 2 hours 22 immediately following onset of the release. l 23 So that might be something that will require 24 rulemaking or a change in rules and could lead us to have (~T ( ) 25 to do exemptions for the pilot plant amendments. So NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

.. ~. - _. ~ ~ .. ~. _.. 33 1 that's one possibility. 2 A second possibility is, of course, the O. 3 current Part 100 talks about the dose criteria in terms of i 4 whole body.and thyroid. And the TEDE really covers all l 5 the nuclides, not.just noble gases'and iodine. And the 6 TEDE concept as well integrates all of the body organs, ~ 7 all of the other nuclides in a coherent fashion so that 8 you cover everything with a TEDE' dose. 9 And if a decision was made that because of the 10 additional nuclides in the revised source term,.it may be i 11 that after we do the rebaselining, we'll find out that 12 that's important. It may be that we'll find out that it's -13 not important. I 14 For a moment harking back to the decision that 15 got made'after the TID that you didn't need the one 16 percent solids, it may be that it just isn't that 17 important. So we'll find out in rebaselining. 18 And the point of this is this.is important in 19 that later on when I'm talking to you about what the staff 20 plans are, one of the issues that's up in the air is 21 whether we will need rulemaking or exemptions. It makes a l l 22 big difference in the staff's plans if we decide that we l ( 23 do need rulemaking and exemptions. f 24 (Slide) ( 25 MR. EMCH: Okay. Rebaselining. We're going r NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

_... ~... 34 1 to' evaluate' Grand' Gulf and Surry.,-a BWR and a PWR. .They 2 were both: included in NUREG-1150. The reason for picking 3 those_ plants, specifically we wanted plants that were 4 evaluated.in NUREG-1150. 5 ~ It doesn't make much difference in terms of 6 calculating the DBA doses, but in terms of; going further 7 and looking, "What does it mean in terms of the impact for 8 the severe accidents?"; the amount of~ evaluation that was 9 done of these plants in NUREG-1150 provides a base that we 10 can look at to see if it makes any change. And that's the 11 advantage of going with those two plants. It doesn't hurt 12 any.that Grand Gulf also happens to be one of our pilot 13 plants. 14 Okay. We'll calculate the_ design basis 15 accident consequences using the revised source term. 16 We'll perform sensitivity studies to provide us 17 information on the implementation issues, some of which t l 18 I've already mentioned, selective implementation, removal i 19_ of accident mitigation equipment, whether or not rules and 20 exemptions are necessary, all those kinds of things we l 21 expect to be able to look at in sensitivity studies, as 22 well as look at the various kinds of uses that licensees 23 might want to make. You know, take this piece of 24 equipment, this piece of equipment out. () 25' And we probably will look at what happens NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 i

-. -. - -. _... ~. - - , _, -.. - - ~. -. -35 'i 1. without a-spray,'without a containment. I know it seems 2 stupid,~but people in my staff stay up all night worrying { O 3-about things like this. j ? !4-We will also use it, as I mentioned before, to j l. 5; help us scope other potential design and licensing basis Ll .6 impacts. And then,-of course, the last one, which we l- -7' mentioned before, is assess the severe accident impacts of f l i 8 possible design changes. -9 MEMBER KRESS: Does that mean right for a PRA? l U .i 10 MR. EMCH: I don't think so. However, this l 11 isn't one of my stronger areas. Okay? The discussions i 12 that we've had with the people in the staff who are more 13 familiar with this, if you remember, I said that we.were O\\ 14 taking plants that were from 1150. That down here is the L 15 reason for that, is really the reason for that, the idea L '16 that we may not have to actually completely redo any PRA 17 analysis or anything,;that we may be able to tell just by 18 comparisons with the stuff that has already been done in 19 1150. 20 MEMBER POWERS: Eleven-fifty produced for both l 21 of those plants distributions on the source term. Your l l 22 1465 has some genesis from those as some kind of bounding, [ 23 but not too bounding -- 24 MEMBER KRESS: Amalgamation. 25 MEMBER POWERS: It's bounding, but not too i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. [ (202) 234-4433 WASHINGTON, D.C. 20005-3701-(202) 234-4433 l

36 1 bounding. 2. MEMBER KRESS: Yes. %) 3 MEMBER-POWERS: Sort of we don't know what. 4 MR. EMCH: I'm glad to see you have as much 5 trouble describing it as I'do. Yes, sir. Okay. 6 MEMBER POWERS: Well, one of the things we 7 asked for in our' letter was some assessment'on what the 8 level of conservatism of the 1465 source term was. Now 9 you're going to go in, and you're going to do an analysis 10 on-these Grand Gulf and Surry both. And you're going to 11 use a source term that's essentially a point estimate of 12 those ranges. 13 MEMBER POWERS: Isn't that going to elicit 14 somebody asking you a question? 15 MEMBER KRESS: It's a circular argument. 16 MR. EMCH: Okay, let's see it if I can follow i 17 this. Quite simply, we've been here too many times when l 18 you haven't' asked that question, so I suspect.that we do 19 it again. 20 MEMBER POWERS: Quite, frankly, if I was in p 21 the business of intervention and you charted out your 22 point estimate on that, and I said, that's great, and I 3 believe every word of what you said to me, but I also 2 24 notice these very erudite people that did 1150 got some i l 25 higher numbers, and so why don't you use those. NEAL R. GROSS COURT REPORTERS AND 1RANSCRIBERS 1323 RHODE ISLAND AVE., N.W. 7 l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 i

37 1 MEMBER KRESS: No, but the answer here is -- I 2 think the answer here is look at that calculation, and 7..s c s ' '/ 3 it's sort of a benchmark to see if you're using that one, 4 gives you something close to the mean than those others, 5 or a little higher. 6 And then you do this sensitivity analysis, 7 which means you're not evaluating the same plan. You're 8 evaluating the same plan of changes, and they you're going 9 to see what that does to you. 10 I think it is a way to see what the influence 11 of potential use to the for existing plants. 12 I would expect if they feed back this 13 amalgamated source term into calculation -- I don't know n (_/' 14 what that calculation is. That's a design basis 15 calculatica. 16 MEMBER POWERS: No, no. I'm talking down at 17 the botcom here. i 18 MEMBER KRESS: At the bottom. Okay, well 19 that's spin off for the same plants. That's for plants 20 that have had things done to them. 21 MR. EMCH: I think I get a better idea what l 22 you're talking about. I do have a possible answer for l 23 that. I thought some about that myself. 24 You already pointed out that the revise source p 'y ) 25 term was something that sort of grew and could be thought NEAL R. GROSS i COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. I (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

38 1 of as -- 1150 could be thought of as a precursor, at least 2 one of the steps on the way to the new source term. l \\ / 3 How we're going to do it in DBA space, we're 4 going to take it as a point estimate and we're going to 5 plug it into our calculations, and we're going to have 6 other conservatives built around it and that sort of 7 thing. 8 And I don't really thing, in terms of how they 9 evaluate severe accidents, or how they do their 10 evaluations, I don't think it's going to make any 11 difference at all. 12 The techniques, the approaches, the 13 calculational methods are just so much different, they ,~ \\-) 14 don't use point estimates in severe accidents. They use 15 ranges, they use distributions. 16 And so, it's not like you can just simply say 17 for a severe action evaluation I'm going to take what 18 happened in DBAs, and I'm going to take the next two 19 columns out of NUREG 1460 and plunk it in and see what 20 happens. The calculational methods, the MELCORS and all 21 that sort of stuff, already have the underlying basis of 22 the new source term built into them. That's my view of it 1 23 at least. 24 Does that help you? (q) 25 MEMBER POWERS: Actually I'm not the one NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

39 1 that's going to need help. I think you're the one that's 2 going to need help -- ~s ( ) 3 MR. EMCH: Oh, okay, 4 MEMBER POWERS: -- on that question. 5 MEMBER KRESS: Let me tell you again my view 6 of that. 7 MR. EMCH: All right. 8 MEMBER KRESS: You do this DBA calculation 9 with a new source term, and it tells you can do something 10 to your plant and still meet the criteria. That something 11 might be change of leak rate, might be change of valve 12 timing, might be throw away the filter, might be not 13 having a spray. I don't know what it will be. There may 14 be some things that the new design basis tells you can do. 15 Then you say, okay, will we allow that. It's 16 within the new design basis. You say, well, we need some 17 risk information on this. 18 So you take the plant, which has hed a risk 19 analysis done to it, you know what its risk status is, and 20 you redo the risk with these changes in some sort of 21 sensitivity form, and you look a the new risk numbers, and 22 you make a judgment as to whether those changes actually 23 impacted the risk or not. And that gives you guidance on 24 whether you would allow these things, just based on the (. (_,) 25 design basis analysis calculations. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

40 1 That's how I viewed what you're doing. 2 MR. EMCH: I think that's a pretty good ,~ L_j 3 description. 4 MEMBER KRESS: Yes. And I don't know how you 5 do that exactly without -- That's why I asked you if 6 you're going to run this through another PRA, and I don't 7 know how you do it exactly without that. 8 MR. EMCH: Right. What you have in mind may 9 be a little more detailed than what I have in mind, but I 10 have to be honest, what the staff has in mind is still l 11 being developed there, so I can't -- It may be that we'll 12 end up exactly where you said, yes. 13 Okay. Geez, we've already talked about this, p_ \\ i 14 but e.amptes of things that we'll be looking for in the ~- 15 sensitivity studies. We'll first just takes the plant as 16 it sits, no changes at all. Put the new source term in, 17 see what it means in terms of the doses. Then we'll look 18 at possible effects of design changes. 19 By the way nobody should interpret the fact 20 that we've mentioned getting rid of containments and 21 sprays as being a suggestion. That's one thing we're 22 going to look at. 23 We'll look at the importance of first versus l l 24 worst 2 hours, we'll look at the importance of the (,/ 25 different kind of dose methodologies, and just see, does NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

41 1 it make any difference or not, technically. 2 Pilot plants. You probably know the list to -m / T 3 that. One possible surprise to you might be Oyster Creek. 4 Browns Ferry, Grand Gulf, Indian Point 2, Perry, and just 5 within the last few weeks we've decided -- Oyster Creek 6 said they wanted to become a pilot plant and we decided 7 there was enough different, yet enough the same -- it's 8 kind of a hard explanation to draw -- to make them a pilot 9 plant. 10 And if they're totally unique, it doesn't any 11 good to make them a pilot plant because it doesn't teach 12 us anything about the other plants. So they have to be 13 unique in some ways, but yet somewhere or another the / \\ (.) 14 same. 15 MEMBER KRESS: Oyster Creek's the mark 2? 16 MR. EMCH: Actually I believe Oyster Creek is 17 a BWR-2, mark 1, is that correct? 18 MEMBER KRESS: 2 is the -- 19 MR. EMCH: 2 is the BWR product line, so it 20 makes it a pretty early BWR. 21 MEMBER POWERS: You lack an ice condenser on 22 this list? 23 MR. EMCH: Pardon? 24 MEMBER POWERS: You don't have an ice p(,) 25 condenser on this list. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 l

_ ~ -. 1 42 -1 MR. EMCH: There's probably a number of ..\\ 2 things. 1 7,,. ( 3 You'will notice there's four BWRs and 1 PWR. 4 In some ways we were sort of'at the mercy of who applied i 5' as.to who went on the list. j l 6 MEMBER SEALE: It sure looks like GE always 7 throws the plants away and starts over, doesn't it? 8 MEMBER POWERS: Yes, but they meet the CDF 9 criteria. 10 MR. EMCH: There was a time when I was in the i 11 tech spec group that I used to think that. 12 Okay, staff plans. 13 We're going to send a letter to NEI, telling \\ 14 them the things that we've just been telling you here. 15 We're go'ing to perform the rebaselining analysis. At the 1 16' same time that we're starting the rebaselining we will 17 begin review of the pilot plants. Probably slowly, bec wa 18 at least need to look and see what kind of changes they're 19 proposing. We at least need to look and see what kind 20 of -- I'll just use the word analysis or calculational ) l 21 credits they're asking for. For instance, there's a myriad of things that 22 23 go in to the calculation about how does it get from inside i~ 24 the containment atmosphere to outside the plant. And so, () 25 we'll have to look through the pilot plants to figure out 1 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

43 1 1 what kinds of phenomena are attempting to be credited by 7-2 the pilot plants so that we can put that into the i \\ '~' 3 rebaselining. 4 And also an important point there is figure 5 out -- Some of these kinds of things may well be phenomena 6 or systems that we've never really attempted to model j i 7 before, and that we don't have calculational techniques to 8 deal with, and if there's a lot of that then we'll have to 9 find ways to deal with that that may include getting 10 contract help or any number of other things. Of course it 11 becomes a complication of the review. 12 As I said before, it will help us determine 13 whether rulemaking exemptions are necessary, or we will rx l / 14 determine after going through some of this. Then we'll ] 15 begin the rulemaking process if it's decided that its i 16 needed. 17 Complete the pilot plant reviews. Issue the 18 amendments, including the exemptions if necessary. 19 This will not be done in a vacuum. Okay. The 20 Commission has expressed a lot of interest in this 21 process, and I'm sure that we'll be talking to them about 22 it soon. And I'm sure probably somewhere around the time l 23 when we make the decision about rulemaking and exemptions 24 we'll have to talk to them probably about the time we get /~'s (,) 25 ready to actually issue any exemptions. I suspect that l l NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

44 1 they'll want to hear some more about this then too. And 2 as we pointed out earlier, when you ask about CRGR that's j ,_s ( ) 3 when they're going to become very much interested. 4 If it turns out that exemptions are not 5 necessary, going back to the generic theme that I 6 mentioned at the very beginning of the presentation, we'll 1 7 take the license, we'll issue the pilot plant amendments, i 8 and then turn around and prepare generic letters so that 1 9 follow-on plants can make their applications quickly, and i 10 hopefully we'll be able to review them quickly without a j 11 lot of reinvention of the wheei i 12 There will always be some plant-specific 13 differences that we'll have to deal with but we'd like to /'^s (/ 14 minimize those. l 15 Along the way we'll complete rulemaking if 16 it's decided as necessary, and then, either this way or i 17 this way we'll eventually start reviewing the follow-on 18 applications. 19 And of course the question everybody always l 20 wants to know, schedule. i 21 We debated whether we should put tentative 22 next to schedule, but we'll just -- 23 Complete rebaselining and decisions on need 24 for rulemaking exemptions, mid-1997. You know whenever (m ( ) 25 somebody uses the word mid that they're hedging ' heir bet. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

i' '45 i l 1' And~then complete the pilot plant reviews in late '97. ] l 2 Now, on the pilot plant reviews, and to some j l 3 extent up here also,.I mentioned a moment ago that we've l 4' seen in some of the discussions we've had with'the pilot ) l l: 5 plants already some calculational credits that I've had l I 6 some of the members of the task force come to me and say, 7 if they want to take credit for that, we don't have a l 8 model for dealing with that right now, and we're going to 9 have develop one or get one, or just decide to leave it 10 out. ) i 11 And if it turns out that we need to do a' lot l t-12 of -- If we need to do a lot of model development, where 13 we have to use. contractors and things like'that, then that x_/ 14 complicates things and would probably affect this date. l l~ 15 And I'm finished, unless you folks have some i l 16 more questions. j; 17 ' CHAIRMAN'FONTANA: Any additional questions 1 18 for Mr. Emch? 19 There's going to be more. 20 MEMBER POWERS: It's just apparent that he's 21 got an awful lot of work ahead of him. l l 22 CHAIRMAN FONTANA: Later on this afternoon '23 we'll discuss what are the things that we should be i 24 discussing at the Full Committee meeting, and get back to 25 that issue. l l NEAL R. GROSS I COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W, (202) 234-4433 - WASHINGTON, D.C. 20005-3701 (202) 234-4433 i l

46 1 okay. Thank you very much. 2 Ms. Mahoney? \\ ) 3 MS. MAHONEY: Yes? 4 CHAIRMAN FONTANA: You're up next. 5 MS. MAHONEY: Good afternoon. I'm Sheri 6 Mahoney from Entergy operations, the Grand Gulf Nuclear 7 Station. I'm a licensing engineer there. 8 Entergy has been very interested in the 9 revised source term for quite some time. When they put 10 the draft out we were looking at it then. And since then 11 we've been following the issue very closely. 12 We're active in participating in the effort. 13 We participate on the NEI Task Force,. and you've heard r\\ i C/ 14 we're one of the pilot plants. We also chair the BWR 15 Owners Group Committee on the revised source term. And as 16 you heard Rich say, we're going to be the BWR rebaselining i 17 plant, and we're very pleased to do that. We're really 18 excited about working with the staff on that effort. l 19 You're going to hear from NEI on some very 1 l 20 specific details later, but we'd thought it would be 21 useful tcr you to hear just a single utilities viewpoint i 22 on implementing the revised source term. 23 There's a lot of issues out there, and these 24 are just the ones of importance to Entergy really. n {) 25 Actually what I've heard from Rich, it really NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

- ~ - -. -. -. -. . ~ -. 47 -1 sounds a lot better than what'we heard in October. We l. 2 thought that we were going down the path of rulemaking and 3' that1that would create a long delay for anybody to be able 4 to use the revised source term. 5

One of the issues that that brought out was 6

that,.even'though there are cost beneficial changes and 7 th'ere are dose changes that everybody talks.about with.the i 8 revised source term, there are safety beneficial changes I 9. that we can get by'using it, and any delay would just 10 delay those changes being implemented. 11 The rulemaking part -- It sounds like that the 12 NRC has decided to reconsider that. They're going to use i 13 the baselining to decide whether or not that needs to 14 happen. But even if they find out that the TEDE and the f l 15 2 hour spotting window is important, we think that there 16 is a way in the current regulatory structure to deal with i 17 that without rulemaking. 18 We believe that the rebaselining should'be 19 performed, but the scope should be limited. And from what 20 I heard from Rich, it looks like that they are going to 21 limit the scope and have that effort completed in a l-i 22 reasonable length of time. We were afraid that it might 23 stretch out such that we might never get finished with the 24 rebaselining effort. () 25 MEMBER KRESS: On your comment on i i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

48 1 rulemaking_--

2 MS. MAHONEY:

Yes? O 3 MEMBER KRESS: -- what are the criteria for 4 when rulemaking is or isn't necessary? How does one make 5 that judgment is what I'm aski.r? 6 MS. MAHONEY: If you can't comply with what's 7 currently in, in 10 CFR, then rulemaking would be 8' required. But as long as you can comply _with that I i 9 mean there are additional requirements that if they're l 10 imposed, there are ways that you can use SRPs and reg .i 11 guides to limit any additional requirements, and I've got 12 a slide on that. 13 So we think that the implementation should go O I V 14 forward as quickly as possible,-and that it should_be'high-15 priority. 16 I told you about when we were looking at some 17 safety improvement. .I wanted to give you a couple of 18 examples of what we're talking about. 19 This first one is a mouthful. It's, 20 elimination of the automatic isolation function of 21 selected primary and secondary containment penetrations. 22 These are penetrations that do not communicate 23 directly with the contaminated atmosphere. There are 24 systems like instrument air, firewater, plant service 25 water, variable chilled water; systems that we found in i. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 234 4433

49 l 1 our IPE to be very important for mitigating consequen' cts 2 of the accident. ,3 e i . N l 3 Currently, these systems have to isolate from 4 the start of a release, immediately. 5 MEMBER KRESS: What signals them to start? 6 What's the automatic signal? 7 MS. MAHONEY: It's LOCA. 8 MEMBER KRESS: LOCA? 9 MS. MAHONEY: Right. The LOCA signal 10 isolates -- 11 MEMBER KRESS: So you look at the pressure of i 12 the primary system?: 1 13 MS. MAHONEY: I'm not sure about that. I , ~^\\ \\ k I k/ 14 don't think it's on pressure. I think it's on the LOCA 15 signal that you'll have an isolation. j 16 MEMBER KRESS: All the things that go in to 17 make a LOCA signsl. l 18 MS. MAHONEY: Right. Water level and end the 19 pressure. 20 Right now the way it works, once those systems 21 isolate immediately the operators are trained and required 22 by procedure to go ahead and bypass the isolation. 23 Something they do in the simulator, and they found that 24 it's important to do that because if you lose those (,j 25 important systems you're just going to cascade; you're NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISt.AND AVE., N W. (202) 234-4433 WASHINGTON. D.C. 20005-3701 (202) 234-4433

~.. -~ 50 l 1 going to lose more and more important systems. l~ 2-Like'on the instrument air, you're going to O 3-lose air to your valve actuators; you're going to lose it 4 to your airlock seals. For the cooling waters you're l l. 5 going to lose a number of different cooling water systems 'l 6 if you don't have'the make-up for those. 1 l-7 The second example -- 8 MEMBER SEALE: I was going to say, I guess 9 there are adverse consequences of losing and then. I 10 regaining these by isolation or by bypass, if you will -- '11 MS. MAHONEY: Right. I 12 MEMBER SEALE: -- that you could avoid if you l l l~ 13 didn't lose them in the first place. L O l V 14 MS. MAHONEY: Exactly. Exactly. Because you I l 15 need them. The operators are going to go ahead and bypass 16 them, so you've got that delay. The operators are 17 focusing on getting that done, instead of focusing on 18 mitigating the consequences.of the accident. They should 19 he able to have this. With the NUREG they would have it. 20 We've got a fairly aggressive safety analysis 21' staff at our plant. We're lucky enough to have those h 22 guys. They understand the analysis very well. If we 23 could find any other way to get this to happen we would 24 have already done it. The NUREG is the only way that we n 25 have found that we're going to be able to effect that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

_ _ _. ~.. _ - 51 1 change. 2 The second change -- you've already heard Rich O 3 talk about this -- the relaxation of the general automatic 4-containment isolation value closure _ times. Those closure j f' 5' times are very stringent. Big valves have to close in 6 like 4 seconds. There's a lot of stress put on the valves' i i 7 by doing that, and it doesn't seem to make sense that you I '8 have to have all this stress on the valves. You have to I c 9 increase your ESF bus loads immediately when the release l 10 hasn't even started yet. r 11 I mean, I don't think I can add much more to i 12 what Rich said. 'But that's a safety benefit, because you { i 13 can reduce the component stresses, you can reduce the ESF -l V 14 bus loads. .i 15 When I came here today,'we kind of already 16 thought the NRC had decided that Part 100 had to i 17 be -- They were going to prevent us from doing that. I i 18 see they're going to use rebaselining to find that out. 19 Within that there's a couple of sections in i i 20 10 CFR, Part 100, that I think the staff believes may ~ '21 cause some problems with rulemaking. And that's, for 22 2' hours immediately following onset, the postulated j 23 fission product release, that would prevent you from using i 24 a 2 hour sliding window. 25 What a total radiation does to the whole body NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005 3701 (202) 234 4 33 3

52 1 in excess of 25 REM, or what radiation does in excess of 2 300 REM, the thyroid from iodine exposure, that would ~s ( ) \\'~'/ 3 prevent the use of TEDE. 4 But we think that there is a way that these 5 additional requirements, that TEDE and the 2 hour sliding 6 window can be accommodated within the current rules. 7 MEMBER KRESS: Without rulemaking. 8 MS. MAHONEY: Without rulemaking. 9 This is where it gets a little -- This is 10 where we kind of depart. 11 We believe that you can use the SRP and the 12 reg guides, and then the 10 CFR 5059 process to bring 13 about these changes. It's the current process, and we . (7, \\._ 14 think that it would just be consistent with the way we 15 already do things. 16 The SRP and the reg guides, they already 17 provide guidance on the dose calculation methods. There's 18 specific details that are in those that are necessary to 19 perform the dose calculations. 20 There's also some places in the SRP where the 21 acceptance criteria for particular changes is some 22 fraction of Part 100. Like if there's an event that has a 23 higher frequency of happening, then the limit's going to l 24 be lower. Some part of a small fraction, maybe that's ,rh 'x ) 25 10 percent, maybe that's 25 percent. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 I

m . ~. 53 i 1 So that's already-there. The SRP and reg i 2 guides'are currently used for that. - And we think that-f 3 those documents could be revised to go ahead-and allow'an 4. option to.use the revised source term, if you included 5' TID -- if-you included.TEDE and the 2' hour sliding window 'f l '6 as some greater acceptance criteria or some list. It j -7 would actually be more requirements placed on using the 8 NUREG. I 9 MEMBER KRESS: And that would go a lot faster 10 than rulemaking? 11 MS. MAHONEY: We believe so. Because the -12 rulemaking, by our experience, 3 to 5 years is.'not .13 unusual. And we believe that if it goes down that' path 14 it's just going to be that much longer before we can take-15 advantage of the safety beneficial changes. 16 CHAIRMAN FONTANA: Is thie likely to end up as 17 a decision by a legal staff? 18 MS. MAHONEY: Probably. 19 CHAIRMAN FONTANA: Sorry. 20 MS. MAHONEY: I'll try not to outguess them. 21-Yes. Once 5059 starts getting involved it's start getting 22 a little squirrely. But once these documents.are revised I' j 23 then 5059 applies. Because TID is not part of the 24 regulations. Licensees have committed to use it; there 4 25 was nothing else. We had to use a TID source term. Now NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS j, 1323 RHODE ISLAND AVE., N.W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

_. _ _ _ _ _. _ _. _. - _ _ _ _ _ - _. _.. _ _.., ~. _ -.. 54 1 there is something else. 2-So it's the commitment, not the regulation lO 3' that ties us to the TID source term. And you change your l l 4 licensing basis and your commitments through 5059. We 5 think it's appropriate It's consistent with the way we f 6 do business now, and we'ought to take advantage of it. 7 The use of rebaselining, we're very excited I 8 about this. We think that there's a lot that can be 9 gained, because NUREG Fortune 65 doesn't really give you i 10 all the details necessary for performing the~ dose 11 calculations, but the EPRI framework document does. It 12 was developed for that purpose, and we think that in the 13 rebaselining the NRC can take advantage of what's in the 14. EPRI framework document to validate those values,'to 15 improve on those values. Those things could then be put 16 in the SRP as guidance for licensees. 17 The scope of the rebaselining effort. To 18 begin with we thought that this might stretch out to be 19 years, but it's a much shorter schedule than we thought. 20 So I'm really actually not that concerned with this 21 anymore. I would say the way that the NRC wants to do'it 22 sounds good, and that we are more than happy to i 23 participate in that effort actually honored. 24 MEMBER POWERS: I noticed in the examples that () 25 you selected at the beginning of your talk, you picked l NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE. N.W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433 L-

55 1 examples where I think the confrontational difficulties 2 that arise in going and applying 1465, you've avoided 7._s I ) 3 those. 4 Has that been a conscious decision? 5 MS. MAHONEY: No, actually not. We just 6 looked at all the changes that we had and said which ones i 7 have the safety benefit, and they just happened to be ones 8 that are very simple, really. 9 MEMBER POWERS: Yes. There are really ) 10 straight forward applications of the source term. 11 MS. MAHONEY: Yes, that's what we think. j 12 Not done on purpose. I mean, there are 13 changes that we're interested in that would be cost /^h xj 14 savings changes, but we're more interested in these few 15 because they're a hard spot. 16 MEMBER POWERS: And I think a lot of us -- I 17 think there are people, myself included, that think cost I 18 savings changes do have safety benefit because it allows 19 resources to go to safety of other creas -- 20 MS. MAHONEY: Right. 21 MEMBER POWERS: -- so I wouldn't be apologetic j 22 about it cost savings. 23 What I'm interested in is, do you think you'll 24 ever get into items that are computationally difficult? '(,/ 25 MS. MAHONEY: Yes. Absolutely. I mean it may NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C, 20005-3701 (202) 234-4433

m. 56 1 be a'little bit down-the road, but we definitely will. I 2 mean,-we're a fairly aggressive plant, so we would -- i 3 MEMBER POWERS: I've noticed that. l 4 MS. MAHONEY: -- so we would intend to take 5 advantage of whatever we could, without being stupid; '6 without cutting into your margins so severely that it-j 7 would limit any other possible changes'you.might want to' i -8 make. We're pretty concerned about keeping a fairly:large 9 margin. 10 CHAIRMAN FONTANA: Wait a minute. ~Before you ~! i 11 remove that -- . 12 MS. MAHONEY: Yes? 13 CHAIRMAN FONTANA: -- what do you.have in mind 14 about another research project? i 15 MS. MAHONEY: Well, that's what Ilwas talking i 16 about. As we got into rebaselining it just might balloon; 17-that there's one other thing that needs to be looked at, 18 and one other, and one other, and that it would just never 19 end. 20 So we were thinking that there should be 21 finite criteria for what rebaselining was supposed to 'do. 22 CHAIRMAN FONTANA: I see what you had in mine. I 23 MEMBER SEALE: Finite and durable [ 24 MS. MAHONEY: Right. 25-In order to achieve the safety benefit without b NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.' (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

57 1 undue delay we request the ACRS to endorse early 2 implementation of the revised source term, through this ) 3 process if necessary. That remains to be seen, but we 4 think that is appropriate to do it like that. If this 5 were current practice, we would encourage that. 6 CHAIRMAN FONTANA: Thanks. Any additional 7 questions from the committee? 8 Any questions from over there? 9 Later, again, we'll discuss what we should 10 take up with the Full Committee. 11 MS. MAHONEY: Right. 12 CHAIRMAN FONTANA: Well thank you very much. 13 You make some cogent arguments, particularly with respect g

V 14 to the automatic isolation.

That looks like that it's 4 15 really important. 16 MEMBER SEALE: Yes, the committee has a 17 history of being concerned about ambitious requirements, 18 or let's say high level requirements being based on the 19 performance of those valves, limiting their competence or 20 their capability to do anything. 21 MS. MAHONEY: Right. 22 CHAIRMAN FONTANA: Well, thank you very much. 23 MS. MAHONEY: Thank you very much. 24 CHAIRMAN FONTANA: The next area is the EPRI ( '; i j 25 report which is scheduled for about an hour and a half. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

58 1. I think it would be a good idea to take a. 2 break now, and be back at 2:35. O. 3 (Whereupon, the foregoing matter went off the 4 record at 2:16 p.m.) 5 CHAIRMAN FONTANA: The meeting will readjourn. 6 Readjourn? What did I say? We're going to start up 7 again. This is what we're going to do -- reconvene. I 8 The next speakers are from Nuclear Energy 9' Institute, and Mr. Kurt Cozens is going to be the next 10 speaker. Are you on at the same time? 11 MR. COZENS: Yes, I was going to introduce 12 Dave. 13 CHAIRMAN FONTANA: Oh, you're going to do 14 that. Okay. I got you. 15 MR. COZENS: Good afternoon. I'm Kurt Cozens 16 from NEI. I am the Project Manager at NEI responsible for 17 the revised source term implementation. I also_ chair the 18 NEI task force on revised source term. 19 We have two presentations, actually, today. 20 The first one will be dealing with our framework document, l 21 what it is, and I think we've heard a fair amount about 22 that already, so that may help our speed of presentation. 23 But we'll also be discussing in a little bit more detail, 24 but still at a fairly high level, the pilot plants and the () 25 projects that they are intending to implement through this NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234 4 33 WASHINGTON, D.C. 20005-3701 (202) 234-4433

59 1 process to give the ACRS an appreciation for what the 2 current level of thinking is and some of the general (~), 3 approaches that will be addressed. 4 That presentation will be done by Dr. Dave 5 Leaver'from Polestar, who is an EPRI contractor. 6 And before I go on and leave the podium to 7 Dave, let me make one editorial change in how we are 8' addressing some things. The' framework document was 9 actually prepared and written by EPRI under the -- Dave 10 Leaver and Polestar being the primary authors on it. I 11 wanted to give appropriate ' credit tx) EPRI for their good 12 support in this area. 13 And with that, once Dave is done, I'd like to 14 come back and talk to the ACRS about some procedural 15 approaches that we've recommended to the staff on how we 16 might implement the revised source term. 17 So_with that, let me turn the microphone over 18 to Dave. And when he's done, I'll come back. 19 CHAIRMAN FONTANA: Okay. 20 DR. LEAVER: Okay. Is that loud enough? Can 21 you hear me okay? 22 Okay. Thank you very much, Kurt. 23 I appreciate the opportunity to speak to the 24 subcommittee on revised source term. I want to recognize () 25 and point out my colleague, Jim Metcalf, back there who NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234 4 433

60 -1 worked on this framework document' effort and is working on 2 revisedEscurce term applications to operating plants '3 closely with me. 4 Also, we have here a number of the licensees-j 5 who'have-submitted -- representing licensees who have 6 submitted applications of the revised source-term for 7 their plants, as well as some additional licensees that 8 are interested in the subject. And it may be that some L 9 questions come up that would be appropriate for them to 10 answer. We can have the advantage of being able-to call 11 on them. 12 Okay. I'm going to talk about three things, ) i 13 three areas. First, just a very brief perspective on the i ( i 14 evolution of the revised source term, how it came about; 15 and secondly, talk a bit about the framework document, the 16 EPRI/HEI framework document, which Rich Emch discussed in 17 his talk as well, some of the information that we had 2 18 provided in the -- what I would I guess call Rev. O of 1 19 that document in late 1995. 20 And finally, I'll talk at a high level on]y, l 21' just because of time constraints here today, on the 22 examples of pilot plant applications. And I'll. mention 23 the TVA Browns Ferry plant, the Perry plant, which is 24 Cleveland Electric, Con. Ed.'s, Indian Point 2, and GPU 25 Nuclear's' Oyster Creek. l NEAL R. GROSS l-COURT REPORTERS AND TRANSCRIBERS I - 1323 RHODE ISLAND AVE., N.W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 I-

61 1 Now, as far as the development of the revised 2 source term, we started thinking about this in the late I ) / ~- 3 '80s because of the ALWR project. What we had was, in 4 effect, new design plants, certainly taking advantage of 5 existing improvement in technology, but nonetheless, the 6 idea was to be innovative and make these plants better 7 plants, better even than what we have -- than today's 8 modern plant. 9 And one of the areas that we thought was 10 important to look at was the source term, because of the 11 fact that a lot had been learned since the mid '60s when 12 the technical basis for the existing DBA source term was 13 developed. A lot was learned from the aftermath of the / 's (- 14 TMI accident. 15 There was a tremendous amount of severe 16 accident research that was done, experiments, NUREG 1150, 17 all kinds of things that suggested that we could be more 18 accurate in the way we describe the source term, which in 19 turn would be beneficial to the design, the idea being, 20 let's design the ALWRs for an accident that is more like a 21 real accident, rather than one that is really somewhat 22 artificial, which TID -- not that TID hasn't done well by 23 existing plants. I 24 So we started this effort in 1989, and in '91 (~% y,) 25 we submitted two reports to NRC on revised source term for NEA,L R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISt.AND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

62 ~ 1 ALWRs,Lalong.with changes to the utility requirements 4-2~ document. And just for those of you that may not be 3 familiar with that, that's the industry's set of' design 4 requirements.for'the advanced plants that has been worked 5 on here over the.last five to six years, sponsored by the 6 U.S. utilities, overseas utilities, and the Department of 7 Energy. It-has been. reviewed by the NRC, the utility 8 requirements document. 'And, in fact, an SER_was issued. 9-Anyway, so the basic idea of the revised -10 source term and the technology was captured in these 11 reports and in the URD. The NRC then published its draft 12' NUREG 1465 in the middle of '92, and then'a final.in.1995. 13 As Rich Emch mentioned, the NUREG 1465 l', 14-primarily focuses on the release part of the source term. 15 That's where the details are on the time and chemical form i 16 and release magnitudes. And our work is -- I would say -17 compares quite favorably to what is in 1465. We really 18 have no quarrels with what's in 1465. 1465 treated the-19 removal part of the problem only in a general way, and we 20 have, through our ALWR work, as well as work on operating 21 plants, have gone' ahead and developed methodologies for l 22 doing that part of it, an'd particularly in areas that ? -23 weren't covered'in 1465. 24 Now, the NRC issued two letters in 1994 25 discussing the application of the revised source terms on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS I 1323 RHODE ISLAND AVE., N.W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

63 1. operating plants and indicating this was something that 2 could be done cautiously, and mentioned the fact that 3 there could perhaps be relaxations to an operating plant's 4 simplifications that could be achieved with maintaining-i 5 safety. 6 And on the basis of these letters, NEI and 7 EPRI and the utilities wanted to consider this in more 1 8 detail, so the industry developed the framework document 9 over the late '94/'95 timeframe and submitted it to NRC.at 10 the end of 1995. '1 In parallel with the framework document, there 12-were some pilot-plants that were interested in applying a 13 revised source' term. Three of these applications were fi- , b 14 submitted in 1996, and there will be several more, or at 15 least a couple more anyway, in 1997. And I'll be talking 16 about several of these -- the framework document, as well 17 as several of these pilot plant applications, at kind of a 18 general level. 19 Now, the framework document is -- the { l 20 objectives were to - I guess we wanted to try to meet s l - 21 some industry needs and'some NRC staff needs. First, we i i 22 wanted to support licensee efforts ~to apply the revised ) 23 source term and to do it in a safe and cost-beneficial j 24 way. We wanted to provide licensees with a consistent O g 25 approach, so that we could avoid a situation of having -- NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234 4 33 WASHINGTON, D.C. 20005-3701 (202) 234-4433

64 i 1 if 20 plants do it, have 20 completely different ways of j 2 doing'it. That's not a good way to do business if you can O-3 avoid it. 4 And finally, we wanted to obtain NRC staff i 5 acceptance of the generic approach, so that the licensees 6 would have some confidence that they would know how to 7 proceed. And in parallel, we felt that some pilot plant ~ 8 applications would put some meat on these bones,.and so I l 9-the pilot plant process, as I said, is going on in 10 parallel. 11 Now, the initial effort on the framework 12 document was submitted the end of '95. We have had a 13 number of meetings with NRC, as I believe Rich mentioned, !V 14 perhaps four or five over the last year and a. half, in l l 15 which we've gotten a lot of oral feedback from the staff. L 16 We have learned quite a bit from doing the plant-specific 17 applications _that we've done so far, which I'll talk about 18 more in a moment. We anticipate getting written comments 19 from the staff. I believe Rich mentioned today that that 20 is their plan. 21-So we are giving consideration to updating the 22 framework document to reflect all of this experience. And 23 what I'm' going to present to you in the next several 24 viewgraphs is -- I guess the best way to describe it would 25 be a' snapshot of what our current thinking is, which has NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005 3701 (202) 234-4433

65 li departed a bit from where we were in December of '95 with 2 the original issue of it. And it's possible that it may 7,b~ 3 evolve some more, depending upon what comments we actually 4 get from the NRC. l 5 But we're -- I guess the message I wanted to i l 6 convey is that we're trying to listen to what people are ~ 1 7 saying in comments and what we're learning from-our own 8 applications, to try to make the document even better than j 9 it was the first time. i 10 Now, this staff -- apologize for all the f i 11 words. I'll'get this all on one slide, just you can kind 12 of compare them, one to the other. But-Rich Emch 13 mentioned principles that were -- the'four principles that r~% q 14 were in the December or November 1995 framework document, ) ~- 15 and we have retained those principles, although we i 16 anticipate possibly there may be some changes to update 17 them. l 18' And we also are considering adding'two I 19 principles. This could -- what you see here could change, 20 depending upon things that we learn here in the next few I

21 months, in terms of how extensive an update we do to the j

22 framework document. But let me just go through these 23 principles quickly. 24 The first one is the one that Rich mentioned, () 25' which is basicallf you don't have to backfit revised NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE N.W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

66 1 source term.to operating plants. It's a licensee choice. 2 Secondly, the concept of substituting NUREG O 3 1465 and' associated removal methodology, which 1465 may 4 not have fully covered, as I mentioned, that that's an 5 okay concept, to substitute that for the existing DBA f-l .6 source term and along with maintaining an~ adequate' margin 7 of safety. 8 The third principle had to do.with selective L 9 implementation.of some, but not all, aspects of'the l L 10 revised source term. We recognize that staff ~has some i 11 concerns about that, and we certainly plan to consider-i 12 staff comments on that. We have'1 earned some things,about I 13 this since we wrote this principle two years ago that I ^ l_ - 14 think could be reflected in the' modification as well. '15 The fourth principle is -- this is a modified 16 version'of-what was in the November '95 document, and what 17 we're saying.here is we think that existing Part 100 18 requirements, which are whole body / thyroid, are -- first-19 of all, they're required by regulation, they should be -20 met,'they are adequate for safety, with the revised source -i 21 term,.we believe. [ -22 We are also saying that the TEDE dose with the 23 worst case two-hour interval, that calculation will be 24 provided even though the regulatory basis would continue 25 to be the Part 100 regulatory limits, which is what's in NEAL R. GROSS } COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433 ~ _ ~

1 67 i 1 the Code of Federal Regulations today. ) 2-The fifth princ ple, which is a new one that 3 we're considering, is stating that in applying a revised 1 4 source term the-existing.GDC 19 requirement, which is the i 5 requirement for control room operator dose, if you'll i 6 recall,.that we believe that based on the way the Code of I i 7 Federal Regulations language is written -- this is just 8 our opinion, of course -- as well as from a technical 9 standpoint, that that requirement could be met either by ' 10 calculating the whole body and its equivalent to other 11 parts of the body, which are the words out of the Code of 12 Federal Regulations today, or by calculating the'TEDE 13 dose. k/ 14 .And then, finally, the sixth principle, which m 15 is a new one that is under consideration, and these words 16 were in the original framework document, but they were 17 diluted somewhat. They were not pulled together as a 18 single principle, and we're now considering having a 19 principle that states that consideration should be given 20 to the integrated safety impact of the application of the 21 revised source term together with the associated plant 22 changes. l 23 And this is the kind of thing that Rich 24 referred to in his talk, although I think he was doing it ( 25 in the context of principle 2. So, I mean, it doesn't L NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

68 j 1 really matter whether~you call it principle 2 or principle 2 6; the idea I think is the same. - (~'i {' _) \\ t 3 Now, I want to just talk a little bit about i 4 this -- principle 2, principle 4, and principle 5. j r i 5 Principle 1 I think is fairly straightforward--- no need I i. 6 to go back to it. Principle 3, I don't want to say any l 7 more about it, really, because vne need to I think hear a 5 8 little bit more.from the staff on that. And in

'l 9

principle 6, we are considering this. 10 At this point, we don't have any more details, 11 really,_to give you-~on what this integrated safety q 12-assessment would involve. But I think it would involve i 13; the same kinds of things that you were talking about when i

O I

14 Rich gave his talk, looking not only at calculating ~the j I 15 doses for the DBA, but in some sense the overall safety j i 16 impact of whatever changes it is that you're making. i 17 CHAIRMAN FONTANA: I guess the question-there l l 18 is: how much work is it' going to end up being if you -- 19 DR. LEAVER: Yes, that's the question. 20 CHAIRMAN FONTANA: And you don't know yet. ] 21 DR. LEAVER: We want to be careful to not 22 overdo it, or otherwise people will get so discouraged ^ 23-with this_whole process th y'll just -- they won't even-24 try it. 25 Okay. So on principle 2, this is just, if you NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 ._. l

69 1 will -- there are words in the framework document that 2 discuss it. This is just an attempt to sort of illustrate ,~ 3 graphically what we're talking about. What you have -- 4 the issue here is what we're saying is we want to be able 5 to apply -- and I don't think anybody is arguing with this 6 -- apply the revised source term as a substitute for the 7 existing source term. And all we're really doing is 8 trying to put in context this idea of margin of safety. 9 If you take, for example, the LPZ dose, which 10 is a 30-day dose -- this could be control room dose as 11 well -- over a period of time, what you might find with 12 the revised source term is there is some period where 13 nothing is released. Then, a release occurs, and at the px t ) \\_/ 14 end of 30 days you have some dose that you -- that would 15 be calculated. 16 If you were to do this calculation with the 17 revised source term, with no changes to the plant at all, 18 just take NUREG 1465 and whatever additional c.arhodology 19 you need to do the removal part of your problem, you come 20 up with some number. Then, presumably, the reason that 21 the licensees are interested in doing this is because 22 there are some plant improvements they could make to 23 simplify O&M, reduce radiation exposure to workers, make 24 plants safer. E's (,) 25 You might see some delta between what you -- NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS j 1323 RHODE ISLAND AVE., N.W. l (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 l

70 l 1 the dose that you would get with the revised source term 2 with no plant changes and the plant changes. The plant p. ( ) i ' 3 changes might result in some modest increase in the dose. 4 This, to us, would be in the spirit of and acceptable in 5 the sense of maintaining a margin of safety. 6 This line here is license acceptable limit, 7 which would be for that particular plant what their 8 licensing basis states in terms of an acceptance limit. 9 That could be what's in the Code of Federal Regulations -- 10 for example, 300 rem for the LPZ, or it's possible that 11 some plants may have been licensed at some thyroid dose 12 limit for LPZ less than 300 rem. 13 Our experience, for the plants we've seen so , - ~. (_) 14 far, is the licensing basis is 300 rem. As long as we're 15 below this line, then the idea is we have done our job in 16 terms of addressing the regulatory -- the margin of safety 17 that's regulated by the NRC. 18 CHAIRMAN FONTANA: Well, you don't really know 19 what that margin of safety is, and that's why I like the i 20 way you drew it, with no top to the arrow. j 21 DR. LEAVER: Yes. I tried -- 22 CHAIRMAN FONTANA: But your point is -- 23 DR. LEAVER: We fiddled with this slide. 24 You're right. That's right. (o; 25 CHAIRMAN FONTANA: If you're belcw that line, v NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234 4 33 WASHINGTON, D.C. 20005-3701 (202) 234-4433

71 1 you'll know that your -- ) 2 DR. LEAVER: You know you've got a problem. t i 3 CHAIRMAN FONTANA: Yes. 1 4 DR. LEAVER: Exactly. ] 5 CHAIRMAN FONTANA: Yes. 6 DR. LEAVER: Now, this slide says nothing 7 about -- 8 CHAIRMAN FONTANA: Of course, there's another 9 part of this, too, is that if you make a plant change, 10 there might be some unanticipated consequences. That's -- 11 DR. LEAVER: Right. 12 CHAIRMAN FONTANA: That's an argument. 13 DR. LEAVER: This slide does not address the ,/ 3 a 14 question of the integrated safety impact. \\m/ l j 15 CHAIRMAN FONTANA: Yes. 16 DR. LEAVER: And that's why I think we need to l 17 do, you know, something -- whether it's a combination -- 18 you know, it may be that you can do something generically 19 that would give you a lot of confidence, and that would 20 minimize what one might have to do on a plant-specific 21 basis. But frankly, we don't -- obviously, you can't say 22 this categorically about every possibility. But 23 generally, the kinds of changes that people are making we 24 don't see as having a big effect on risk. m s ) 25 As you were talking this morning or earlier .xs NEAL R. GROSS i l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

72 1 this afternoon about leak rate, for example. You know, 2 leak rate will increase the dose, no doubt about that, but s \\ \\ / '~' 3 hopefully not very much and we can calculate that. And in 4 any case, it's not a big risk issue. 5 MEMBER SEALE: Well, delta could be negative. 6 DR. LEAVER: It could be. That's right. It 7 wouldn't have to be positive. Could be negative. 8 MEMBER SEALE: As a matter of fact, if you 9 slow her valves down, they probably seat better when they 10 do seat. 11 DR. LEAVER: Yes. And that might be a hard 12 thing to calculate and capture in a risk sense, but yes. 13 And I agree with what Dana Powers said earlier today, too, (3 (_-) 14 which is that if you can do things that simplify O&M, 15 reduce costs, presumably you can do a better job on the 16 things that really matter. Again, that's a hard thing to 17 quantify, but I think that's a real effect. 18 Okay. Now, on principle 4, which is the one 19 having to do with Part 100 and the TEDE dose, and this is 20 -- Rich Emch's presentation dealt in detail with the two j 21 frameworks, if you will. We have thought a lot about 22 this, because there is a great deal of stuff here in terms 23 of if we have to wait for a rulemaking it just puts a 24 tremendcus cloud of uncertainty over this whole process, ,(,) 25 and I think people are going to get discouraged. NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. (202) 2344 433 WASHINGTON, D.C. 20005-3701 (202) 2344433 l l

l-73 i i 1 Licensees.will get discouraged, i L- .2 But what we believe about this -- in fact, NEI ! O~ l '3' did send a letter to NRC staff on this subject a couple of l' 4 weeks ago that spelled out our thinking. We think that 5 the existing Part 100 requirement for whole body and 6' thyroid is,.in' fact, adequate for' safety when using the. .j i j 7. revised source term. 8. On the basis'of our experience, and I.will l 9 show you a calculational example'in a moment ---and let me i 10 try and say this in a way that it's understood. For 11' operating plants, the=whole body and thyroid. doses.that' l 12 are done under Part 100 we believe will be of the same 13 order as-TEDE, in terms.of fraction of the licensing l 14 acceptance limit. 15 So,'in other words, we would not expect ---if. 16 you were.to do the whole body and thyroid doses under-17 Part 10'O for a revised source term application for'some: 18 plant, Land then turn around and do the TEDE 6alculation, 19 we would not expect-that you would get a drastically 20 different result in terms of the acceptability of the 21 doses. Okay. l 22 -CHAIRMAN FONTANA: Are you proposing that the.- I: 23 two calculations be done? 24 DR. LEAVER: Yes. We're proposing -- what 25 we're thinking about anyway at this point -- this is not a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433 .. ~.

74 1 done deal;'but.it's our current thinking:-- is that what 2 we would put in the framework document is that plants '3' should do the Part 100, which specifiesfwhole body and -l 4 thyroid and the zero to two hours, because that's the 5 regulation and that's what you have to do. ( 6 And, in addition, the plants would provide a 7 parallel off-site TEDE calculation as part of their f I 8 submittal. Now, that would not be the regulatory basis. l. 9 The regulatory. basis would be what's in the regulation. f .I 10 But this parallel off-site TEDE calculation would give f 11 confidence that there is not something funny going on with 12 TEDE. 13 Okay. The last principle I wanted to talk i I t 11 4 about was GDC 19. What we're saying.here is something. I 15 that we've -- I think we've talked informally with the j 1 l 16 staff about. I know people off and on hhve been talking 17 about this for a number of years in the industry. GDC'19, j 18 as written, says -- and I have put some quotes in here -- l l l l 19 "that control room doses should not exceed five rem whole L 20 body or its equivalent to any part of the body for the 21 duration of the accident." 22 Now, when you go'to the standard review plan, i 23 that's interpreted. And what that says is five rem whole i ' 24 body, 30 rem thyroid, and 30 rem skin, 30 days. And .I () 25 that's pretty much what people have done, at least the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 4 1323 RHoDE IS!AND AVE., N.W. (202) 234 4 33 WASHINGTON, D.C. 20005-3701 (202) 234-4433

~ .. -.. ~. 75 l 1 plants that were done post SRP. l 1 2 Okay. Now, it's our opinion that an equally O 3 valid -- and I would say valid both from a regulatory and l 4 a technical standpoint, to the extent that, you know, we 7 .5' can venture forth an opinion on this matter -- i's that .i 6 under GDC 19 it would be equally valid to calmdate TEDE, 7 since'it includes the whole body component, and it ~ 8 addresses an even more comprehensive set of organs. 9' So we think that TEDE should be an acceptable l 10 alternative to the existing -- to the interpretation'of i 11 GDC 19, which is in the existing SRP. And our thought is l 12 that we would attempt to capture this concept in an update 13 to the, framework document. We have kind'of hinted at this L i 14-in the existing framework document, but it wasn't very i i 15 visible. So that's what we're thinking about. I l- ~16 Okay. Now, the last thing I want to say about i 17 the framework document is just briefly on methodology. L 18 The framework document I think really is -- has got three l i 19 elements to it. One element I did not talk about, but we I I 20 have a section in there that talks about why do we even 21-care about doing the revised source term for operating l-22 plants. And, of course, what that gets down to is 23 improvements in the plant, and we've attempted to 24 categorize the types of improvements that licensees are l 25 interested in. And, in fact, Rich Emch had a slide on NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4 33

76 c 1 that at the beginning of his presentation. 2 And I would be happy to answer any questions s s. ( / '~' 3 for any of the licensees that are here, talk to you about 4 why they are doing this. But in the absence of any 5 questions, I'll not talk about that further. 6 The second thing in the framework document are 7 the principles, which I just discussed. 8 The third area is methodology. We have 9 attempted to address methodology. On the release side, 10 that was easy, because we basically said, "We're pretty 11 happy with NUREG 1465. If you want to do some':hing 12 different, you have to justify it." 13 On the removal side, we have attempted to 'w 14 define what we believe would be an acceptable methodology. 15 We have not been able to address all of the details. Some 16 of these calculations are fairly complex, and they just 17 aren't -- there's just no way that in a generic document 18 that is intended to cover all plant designs and all 19 situations that you can really cover that level of detail. 20 But we do have some modest level of detail i.n i 21 there, and the focus on the removal is -- deals with 22 removal of airborne aerosol, because that's really the 23 name of the game for the revised source term, assuming 24 that you control pH and maintain your iodine as I-minus, /m i ) 25 as an aerosol. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

77 1 1 MEMBER KRESS: In those considerations of

n)-

2 removal mechanisms, do you think it was appropriate to \\ / 3 allow diffusiopheresis as part of that? 4 DR. LFAVER : Diffusio? 5 MEMBER KRESS: Yes, in terms of design basis 6 accidents. 7 DR. LEAVER: Yes. Diffusiopheresis is 8 included -- for those of you that don't know, 9 diffusiopheresis is where aerosol would be driven to a 10 cold surface by the condensation of steam on that surface. 11 We have included diffusiopheresis effect in work that we 12 have done on the AP600, where you have this massive steel 13 shell, which has a water film on the outside, and which is n i I L' 14 designed as part of the design basis to eventually suck 15 heat out of the containment. You are going to get steam 16 condensation on that surface. 17 For operating plants, we have not included it, 18 simply because we were unaware that there are any 19 situations whera you really would be able to take credit 20 for it. For exampJ.e, for a concrete containment where 21 heat removal is by sprays or by fan coolers, it is not an 22 important effect. So it's not in there now, and I don't 23 have any plan to -- we don't have any plans to put it in 24 there. p(,) 25 MEMBER KRESS: Is it part of the spray NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

i 78 l \\ 1 efficiency? + i 2 DR. LEAVER: Well, you can get steam , OG 3 condensation on droplets. Yes. That we have included in v I 4 our model for spray removal. i t 5 MEMBER KRESS: The reason I'm asking is, you 6 know, design basis accidents are' supposed to,-in my mind, 7 scope a lot of accidents. There are sort of surrogate 8 accidents that one uses. And in a lot of accident 7 9 sequences the timing of when there is steam condensation 10 effects, on the sprays and walls, with respect to when the 11 fission products and aerosols are there, it varies a lot 12 from accident sequence to accident. sequence. 13 And if one used a surrogate accident and 14 allowed some sort of -- I don't know what-one does about '15. that timing, how much steam is in there, and how much 16: diffusiopheresis does one allow in a surrogate design j- / .17 basis accident. When you're looking to -- 18 DR. LEAVER: Yes. I understand. 19 MEMBER KRESS: That's why I asked the 20 question. 21 DR. LEAVER: I understand your question. I 22 think it's an excellent question and one which we could 23 certainly -- it's a little bit hard to talk about unless 24 you're talking about a plant-specific situation. But just O -25 to -- I'll probably say more about this than I should with NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. _ (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4 33

~ . -,_.- - ~. - - 79 1 the time we have, but let me.just try a 30-second or one-L 2' minute -- 3 .What we've done, in general, on the removal I i 4 part of the problem is to try to do it in a reasonably ) .5 conservative way but still mechanistic.. We think that if 1 i 6 you -- and this is -.we recognize that this is.more work l l 7 for the industry and a bit more work for the staff to have 1 l 8 to review these more-detailed calculations, but you really 9 lose an awful lot if you resort to simple models.that 10 completely ignore'certain phenomena, just for the sake of 11-making life simple. ? t 12 You also -- people say, "Well, gee, you know, ) i ) L 13 don't you want to be really conservative, and these simple ! (~N l 14 models are conservative?" And sometimes-they are, but the j 15 problem is they're not always conservative. 16 I have a slide which I'll show you afterwards. 17 I don't have a viewgraph of it. But what we have found is 18 that some of the SRP models are actually non-conservative -19 in certain situations. So it's -- we've tended to try to l 20 do things a little bit more mechanistically, I 21 on the issue of condensation on spray i. i 22 droplets, if you are reasonably conservative in your 23 description of how much steam you get 1-24 MEMBER KRESS: That's the problem. () 25 DR. LEAVER: 'Well, I think we know how to do NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. l (202) 234-4433-WASHINGTON, D.C. 20005-3701 (202) 234-4433

.~ 80 l' that. I don't know. I mean, I think you'd have to look l 10 at an actual calculation and talk about the pros and cons 2 g -3 of that-to really nail that down. But what I'm saying is 4 that as long as you don't go overboard in terms of your 5 estimate of how mucli steam you get, and as long as your I L -6 result isn't overly sensitive to the matters of timing and 7 that sort of thing, I think it's a robust enough process l 8 that you can include it. 9 What we don't want to -- what we're trying to j t L 10 do here is to really recognize the important phenomena and F l 11 not just ignore phenomena that we know are there. It may l 12' be that they're hard to quantify' exactly, in which case we { l '13 have to be careful how we do it. But we want to try to l lDU 14 include them. l p 15' MEMBER POWERS: Speaking of phenomena -- i 16 DR. LEAVER: Yes. 17 MEMBER POWERS: -- that arise that are real, 18 that we know occur, that are difficult to quantify, how 19 have you handled the problem of electrostatic charging of 20 the particles? 21 DR. LEAVER: I guess that's one you could do a i, '22 Ph.D. thesis on. But our sense is that'it probably -- we L 23 have not included that effect in our calculations. Our i 1 24 sense is that if one were to do that that it would l 25 probably - it's probably conservative to not include it. NEAL R. GROSS 4 COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 i

81 1 So we think -- we're pretty comfortable with 2 not including it. We also have other -- enough other i i L' 'i 3 conservatisms generally in what we're doing on the removal 4 side that we think would overwhelm that effect. 5 MEMBER POWERS: Well, I certainly know at 6 least one author that has taken the position that it's 7 conservative to neglect it. But he certainly didn't 8 provide a proof on that. Do you have a proof? 9 DR. LEAVER: I don't have a proof, no. No, I 10 don't have a proof. 11 CHAIRMAN FONTANA: What's not written -- 12 DR. LEAVER: There are a lot of things I don't 13 have a proof for. i ) k' 14 CHAIRMAN FONTANA: What's not written in the 15 last bullet is that the overall -- if you kept everything 16' exactly the same and used the 1465 source terms compared 17 with the other ones, you are clearly going to come well 18 below the old source terms. What's not written there is 19 that you're going to maintain the same level of 20 conservatism considering the plant changes that you're 21 going to put in place. Is that correct? 22 DR. LEAVER: You're saying -- I just want to 23 go back to your first statement, Mario. You're saying l 24 this line here, which is the revised source term with no 77 i ) 25 plant changes, is clearly going to be below what you NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 2344433 WASHINGTON, D.C. 20005 3701 (202) 234-4433

82 1-calculate with existing -- 2 CHAIRMAN FONTANA: I'would guess -- O -3 DR. LEAVER: Not necessarily. 4 CHAIRMAN FONTANA: Well, even so. But I guess 5 I -- what that third bullet-'on the other slide says -- G DR. LEAVER: Yes. 7 CHAIRMAN FONTANA: -- is the delta will be 8 such that you are still under the licensing basis.

See, 9

the bullet doesn't say anything there about plant changes, .10 but'you're implying it, aren't you? .11 DR. LEAVER: Let me just read it and see what l 12 it says. Yes. The intent is that the -- when I say '13 " removal methodology," I mean the rule or methodology h(h 14 that's used in'the application of the revised source term 15 with the plant changes. 16 CHAIRMAN FONTANA: Okay. 'Yes. 17 DR. LEAVER: Yes. 18 CHAIRMAN FONTANA: -Yes. I thought it must. 19 DR. LEAVER: Yes. So this is our intent. I 20 mean, we -- you know, obviously we have to demonstrate 21 this. And the framework for this is that chart I showed 22 earlier as to what we mean'by that. You know, we're -- 1 l 23 CHAIRMAN FONTANA: Yes. l 24 DR. LEAVER: The intent is to stay below this O J 25 line. And then the other thing that this viewgraph is

y NEAL R. GROSS j-COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

(202) 234-4433 WASHINGTON, D.C. - 20005-3701 (202) 234-4433 l \\ -

.~- t i 83 l .1 saying'is that.we are attempting to be reasonably. 2-conservative when we do this quantification. We think j .i l 3 1465 is reasonably conservative. Sure. It may not bound 4' anything anybody can think of, but we think it's i 5 reasonably conservative, and we.think our removal ( 6 methodology approach is reasonably conservative, and we l

j 7

know the DBA I over Os are conservative. So the whole t 8 package we think is comparable to' accepted licensing l 9 practice. 10 Okay. Now, these examples -- I'll go through 11 these fairly quickly, but please, you know, if anything in i. '12 here catches your eye and you want to talk a bit more l 13 about the -- we have the most -- I think for all four of l 14 the. plants-I'm going to talk about we have someone here i 15 from the plant. 16 For Browns Ferry, we used 1465. We followed 17 the framework document in areas that weren't fully covered 18 in 1465, and that included natural settling of aerosol in 19 the drywell, gravitational sedimentation, limited 20 suppression pool scrubbing, considerably less than what's 21 actually allowed by the standard review plan, as a matter 22 of fact. 23 MEMBER KRESS: Any scrubbing credit for 24 saturated pool? 25 DR. LEAVER: We calculated estimated pool NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

~ ~ -. 84 1 temperature, and.'I believe-it's not. saturated, right, Jim? '2 Yes. So we did that calculation. x' ); 3 MEMBER KRESS: Then it was saturated. So you j 4 didn*t have'to --- j l l' ..So the issue -- it' turns 5 DR. LEAVER: 'Right. L 6 out the. thing-that limits you here isn't the fraction of I l -7 aerosol that gets scrubbed for what' flows through the j 8 pool. It's how much doesn't go through the pool. That I 9.. really controls it. 10 And as I said, I believe we end up taking less i 11 credit than what's allowed by the standard review plan. j 12 That's one of those instances where things can be'non-l 13 conservative if you're not careful. 14 Main steam line aerosol retention -- this i~s 15 in the. spirit of what was in the BWR owners group 16-methodology. I don't'know if you're familiar with that, 17 but the BWR owners group developed a methodology which l 18. actually was applied to the TID Reg. Guide source term, 19 which is primarily elemental iodine. And that was done l l 20 and approved by the staff. 21 MEMBER KRESS: Did you do all of these for all 22 of the Chapter 15 DBAs? 23 DR. LEAVER: It turns out for Browns Ferry 24 that only the DBA LOCA -- 25 MEMBER KRESS: Is the only one. NEAL R. GROSS ' COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005 3701 (202) 234-4433

85 1 DR. LEAVER: -- is affected. Had we made a 2 plant change that impacted the result for another (',,\\ t' 3 accident, we would have had to do that. But in this case, 4 it didn't. 5 We used more current thyroid dose conversion 6 factors -- ICRP 30 -- and we calculated existing Part 100 7 whole body and thyroid. 8 The plant changes that were included in the 9 calculation are listed here. There was increased MSIV 10 leakage. It went from -- I don't -- I guess 11.5 scfh per 11 line to 100 scfh per J.ine, 250 total, four lines, 250 12 total. There was fission product holdup and retention in 13 the main steam lines and main condenser. The plant change ( >i 14 was making the tail end of the steam lines and condenser 15 are seismic. 16 We took no credit for charcoal in the standby 17 gas treatment system, which is an exhaust gas treatment 1 18 system that -- for accidents in the reactor building. 19 MEMBER KRESS: But you didn't put in any more 20 iodine other than what's in the 1465? 21 DR. LEAVER: We used the 1465 source term. 22 And then there was also no credit taken for 23 the control room, which is called the CREVS -- control 24 room emergency ventilation system -- charcoal, which is a ( ) 25 charcoal for I believe the recirculation system for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 2344433 WASHINGTON, D.C. 2 2 5-3701 (202) 234-4433

86 1 filtering control room air. 2 Also,.pH control is planned and is under O 'V 3 evaluation-at this plant, and the tech. spec. amendment 4' that went in -- while the calculations included all of r t I l' 5_ these things, the tech. spec. amendment only addressed the L 6 first two. It did not say -.at this point in time, they I 7 have not said anything about charcoal in either the i 8 standby gas treatment system or control room, although I 9 believe at some point in time-it is their intent to do so. 10 CHAIRMAN FONTANA: Is making the condenser i 11 seismic -- does that help because it doesn't leak? It 12 doesn't actually affect any -- f 13 DR. LEAVER: Well -- i I L./ ' 14 . CHAIRMAN FONTANA: -- removal mechanism, does' 15 it? 16 DR. LEAVER: No. No, it doesn't, Mario. But 17 the thing is you can't legally, or at least as the '18 regulations are interpreted by the NRC, you cannot get any -19 credit in a DBA for something that isn't -- you can't show 20 is still going to be there after an SSE. 21 Okay. The dose results for Browns Ferry are j 22' given here, just to give you a sense of what we're doing. I 23 This is thyroid dose, which tends to be the more I i 24 interesting ones, more limiting than whole body. 25 These are the existing results. The low means f NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 l

1 87 j i 1 low -. fuzzy logic here. Several rem -- you know, a ways i '2 away from the limit. O 3 Revised source term you'll see is really quite j i 4 comparable. And by " revised source term" I mean using the l-5 revised source term release and removable methodology with l I 6 the plant changes that I listed on a previous slide. 7 Now, this amendment was submitted to the NRC i c 8 for approval in January of 1996. i l i l 9 Okay. The Perry plant is really quite i ) l 10 similar, and I' won't go through all of this stuff but it's l 11 quite similar to the previous slide. I will just mention, 12 though,- that Perry is a Mark III, which means that it has l 13 a containment building designed for pressure that lO L ~14 surrounds the drywell. And that containment building -- i 15 in-a sense, it looks a little.like a PWR. That l 1 16 containment building has a safety grade spray system. 17 So we hase credited that spray system for this { I l 18 Mark III, and we did an aerosol spray removal calculation, j 19 We could have used the standard review plan formulation 20 for aerosol spray removal, but it turns out that that's.a L '21 fairly simple model. There are effects that are ignored 22 in that model, and so.we tried to be a bit more 23 mechanistic. l 1 24 The plant changes here were -- one of them was 25 elimination of the. main steam isolation valve leakage j NEAL R. GROSS j COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 -- WASHINGTON, D.C. 20005-3701 (202) 234-4433

88 1 control system. That is a system that sucks from between 2 the inboard and outboard main steam isolation valve, ,_s I I, s' 3 discharges through a filtration system in an annulus that 4 surrounds the containment building. 5 We increased MSIV allowable leakage, same as 6 we did for Browns Ferry. There is aerosol retention in 7 the main steam line. In the case of Perry, they have a i 8 third isolation valve in the main steam line. They have 9 the inboard valve, inboard of the drywell, the outboard 10 valve, and then they have a third valve about another 50 i l 11 feet down the steam line which was provided on -- I'm not 12 sure what the reason was for doing that originally in the 13 design, but it is a safety grade seismic valve. / 's (/ 14 So we have credited the aerosol retention out 15 to that valve, but we have not credited the condenser. So 16 they are not planning on doing seismic for the condenser, 17 which by the way is a big deal in some plants. I mean, it 18 involves a lot of analysis and possibly even some hardware 19 changes, enough so that some plants would -- just couldn't 20 -- just would get discouraged and wouldn't do it. It 21 would be too expensive. 22 We took no credit for the charcoal filter in 23 the annulus, which is a rather thin space that surrounds 24 the containment for collecting leakage and filtering it. 1 , ~~ ,() 25 But the HEPA, of course, is in there. We delayed the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

89 1 actuation of control room recirc. by 30 minutes. 2 MEMBER KRESS: Why is that? 7! !x' ~'/ 3 DR. LEAVER: This one? 4 MEMBER KRESS: Yes. 5 DR. LEAVER: Perhaps Emin Ortalam could expand 6 on this. ) i 7 MEMBER KRESS: You did it because you could. I 8 DR. LEAVER: Well, no, we did this because the 9 control system for actuating control room research is 10 significantly simplified, the maintenance and testing of 11 that. If you -- 12 MEMBER KRESS: That's what I mean. You did it i 13 because you could, and it gives you lots of -- 73 \\- 14 DR. LEAVER: Right. 15 MEMBER KRESS: -- lots of -- j i 16 DR. LEAVER: We did it because it's an 17 improvement in plant operations, and we were able to 18 tolerate the very small change in dose. You could hardly 19 even see it. l 20 We had a reduced credit for control room l l 21 charcoal. We were not able to meet our dose limits by l 22 taking charcoal out entirely, which is rather interesting, \\ 23 in the control room. It turns out that the control room 24 in this plant -- I don't remember -- it's a recirculation n(,) 25 system, and as long as you have some modest credit for NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON. D C. 20005-3701 (202) 234-4433

90 1 charcoal filtration, and I believe ne assume 50 percent, 2 your doses do just fine. If you take it out entirely, the .._s i 3 doses go up and we're uncomfortable with that. So we left 4 it in. 5 The package that the Perry plant submitted to 6 the NRC included the LCS removal, increased MSIV leakage, 7 and aerosol retention in the steam line, the no-condenser 8 credit. All of these other changes were in the 9 calculation, but I believe will be the subject of future 10 submittals. 11 Now, the doses for Perry look like this. 12 This, again, is thyroid dose. We did whole body thyroid. 13 In the control room, you were right up against /~n r (_/ 14 the limit. With the revised source term release and 15 removal methodology, and the plant changes that I 16 mentioned, the control room dose is about 16 rem. The 17 site boundary and LPZ doses -- this is zero to two hours, 18 of course, and this is 30 days -- are I think pretty 19 comparable to what they had before. This is what they had 20 before, and this is what we're getting now. And this 21 licensing amendment was submitted for NRC approval in 22 August of '96. 23 CHAIRMAN FONTANA: Now that's zero to two 24 hours. That's not -- s# ( ) 25 DR. LEAVER: Yes, this is zero to two hours. v NEAL. R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. l (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

< - _. ~ _. ~. _.. _ _ _ _ 91 i 1 That's right. 2 Okay. The third example I have is Indian O 3 Point, and this work was done at Consolidated Edison by l 4 Westinghouse. Jim Grover, who is sitting back here, { i 5 prepared this slide. And really, it's very conceptually 6 quite similar to the other applications -- that they used j i 7-1465, they followed the framework document in areas not i 8' covered by 1465, but they also used one of the SRP models. T 9 They used the SRP model for spray removal. 10 In this case, they did look at not only the ) i 11 LOCA DBA radiological accident. They looked at some non-12 LOCA events as well, because they felt that that was j \\ 13 important. And one thing I wanted to mention is they- .f 14 increased the gap release fraction by 20 percent over 15 what's specified in NUREG 1465 in order to account for I i -16 high burnup effects. This is for accidents where long-17 term cooling is maintained -- for example, fuel handling i 18-accidents and the rod ejection accident. I 19 They calculated both whole body / thyroid and 20 TEDE dose, and I'm going to show you those results in a 21 moment. The plant changes that Indian Point made were 22 they removed the in containment filters, both HEPA and 23 charcoal. This plant has a fan cooler system which had, 24 or has, filters in it, and they also have the spray j 25 system. For safety improvement and operations and NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 2344433 WASHINGTON, D.C. 20005 3701 (202) 234-4433

92 1 maintenance simplicity, they want to remove these filters. l',\\ They also eliminated the spray. additive from 2 g 3 the spray. system, and they're going to achieve pH control 4 with trisodium phosphate in the sump. And they made a 5 change to control room ventilation system. They are 6 modifying it-for a pressurized control room. 7 MEMBER POWERS: Can I ask a question about 8 this 20 percent increase in the gap release fraction? 9 DR. LEAVER: You can ask a question.

Yes, 10 sir.

11 (Laughter.) 12 MEMBER POWERS: I was pretty sure I could. 13 (Laughter.) {N \\s-14 .I wonder what.the basis for choosing to go 15 from five percent to six percent gap release fraction was. '16. DR. LEAVER: Well,-no, it wasn't -- this is 17 just for accidents in which long-term cooling'is 18 maintained. The five percent number is -- for example, is 19 the gap release when you're on your way to core melt. The 20 number that is in NUREG 1465 for these accidents is three 21 percent, and so it's a change from three percent to 3.6 22 percent. 23 Is that right, Jim? 24 And this was done on AP600, and I guess it was O (,/ 25 discussed and people felt comfortable with it as adding NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISt.AND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

93 1-margin to account for high burnup effects. That's about f,s 2 as much as I can tell you. Maybe Jim Grover can add to V' -3' that.. 4 MEMBER POWERS: I wonder what we've seen 5 experimentally on these gap releases. There have been 6 several experiments now -- 7 DR. LEAVER: Right. 8 MEMBER POWERS: -- with high burnup fuel. 9 DR.ELEAVER: Oh, on high burnup fuel. 10 MEMBER POWERS: And I think the Japanese 11 experiments, in particular, are measuring the gap release 1:2 for at least the noble gases. I don't know what else,'but 13 certainly for the noble gases. And I wonder if they're 14 seeing numbers that are consistent with that. 15 -DR. LEAVER: I have not seen'. experimental data 16 on the high burnup fuel. I have seen a lot of '17 experimental data on more, you know,. typical burnup fuel. 18 And what we've seen is'tnat the peak gap release fractions 19 are around two percent, maybe two and a half. The average 20 is under one percent, and so we felt pretty comfortable l 21 with -- we felt that five percent was -- provided quite a 22 bit of margin, as did the three percent. L 23-If there is data on the high burnup effects, H24 then I guess we should look at it. I just hadn't seen it. ( 25 MEMBER POWERS: Well, you would not think that NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N.W. l-(202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 l t

94 1 low burnup fuel would be in any way applicable, becauce 2 you're getting a fuel -- a change in the microstructure, 3' and in particular you're putting volatiles out at the 4 boundary. And if memory. serves, I have certainly heard of 5 release fractions for particular tests and particular 't , configurations, etcetera, etcetera, etcetera, where things 7 -- numbers like 20 percent of the krypton inventory is 8 coming out in the experiment. 9 DR. LEAVER: All right. Well, I haven't seen 10 these papers, Dana, but~I certainly would like to look at 11 them. l 12 I don't know ii -- Jim, do you have any 13 comments on-that? 14 MR. GROVER: Yes. My name is Jim Grover with I 15 Westinghouse Electric. i '16 The use of the 20 percent was a number that -- l l 17 or a 20 percent increase culled from the initial gap i 18 release of three percent, up to 3.6 percent, was a value 19 that was agreed upon between Westinghouse and the staff in 20 a' meeting in May of '95, as we were discussing the 21 methodology to be used for the AP600, because the concern 22 was that the NUREG 1465 is intentionally vague in regard 23 to high burnup fuel. I'm trying to say it -- Section 3.6 i 24 talks about "The source term contained in this report is !() 25 based on fuel behavior results obtained at lower burnup NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 3 i 1323 RHODE ISLAND AVE., N W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 2344433 i l e .,-n

95 1 levels where fuel pellet remains intact upon cladding 2 failure," and it goes on. [ l ~ 3 And staff cautions that "Until further 4 information indicates otherwise, source term may not be l 5 applicable for fuel at high burnup levels." 6 So, no, we have not looked at the material, 7 and we're not aware of material that you are referring to. 8 But we believe that this was an appropriate consideration 1 9 of the high burnup effects, essentially that something 10 needed to be done. We had the historical increase of -- 11 by 20 percent, based on -- was it NUREG CR-5009 on high 12 burnup fuel. That was used to, you know, applying that 13 factor, increase the gap fraction from 10 percent to 12 p l 4 A> 14 percent. That's about all of the information I can give 15 at this time. 16 MEMBER POWERS: Okay. I'd caution you that 17 I'm operating from memory, but you might want to look at 18 proceedings of a CSNI meeting held in Cadarache, France, 19 like a year and a half or two years ago, to see what the 20 Japanese have actually been measuring. ) 21 DR. LEAVER: Will do. 22 MR. GROVER: Okay. I know the ANS 5.4 model l 23 does not project anything like this. 24 MEMBER POWERS: It can. ,m. ,(,) 25 MR. GROVER: Yes. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

96 1 MEMBER POWERS: It's not -- it won't take into 2 account the fuel restructure. ,. s ( ) 3 DR. LEAVER: Yes, we'll look at it. 4 Appreciate the comment. 5 Okay. So the dose results were Indian Point, G and here we have a TEDE calculation, just to give you some 7 perspective, comparing TEDE with whole body / thyroid for 8 this plant. j I 9 For thyroid, we have three columns here. 10 First is the existing FSAR. The second is the NRC's SER 11 on this plant, which gives you doses -- that calculates 12 doses somewhat higher than what is in the SER but still i 13 below the licensing acceptance limits. Then here is the (~') ks 14 result with the new source term -- this result being, as 1 15 before, the release and removal side of the revised source i 16 term plus the plant changes. 17 The TEDE calculation, if you look at the site 18 boundary, we did it -- and this was actually worked on by 19 Westinghouse. There is a zero to two-hour and then a 20 worst two-hour. The TEDE limit -- if you were to use the 21 new Part 50 rule that the NRC issued, or maybe it hasn't 22 been ist uud yet but is about to, the limit is 25 rem. 23 So you can see, first of all, that the TEDE 24 dose is maybe 60 percent, something like that, which is ( j 25 not wildly different from what you see here. This is a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D C. 20005-3701 (202) 234-4433

97 1 little bit higher, but it's not wildly different. And ths 2 other thing that's interesting is that the worst two-hour 3 gives you about a 10 percent, maybe a little less than 10 4 percent, increase in the TEDE dose. 5 We think this is fairly typical. I would 6 point out that this plant does not hold up the leakage 7 that -- what goes into the containment immediately begins 8 to leak, and that leakage goes directly to the 9 environment, because there is no structure around the 10 containment that collects leakage and filters it, for 11 example. Where there would be a delay, that's part of the 12 reason why you don't see much of a difference between the 13 zero to two-hour and the worst two hours because zero to 14 two hours is almost the worst two hours. 15 A plant that held leakage up, you would see 16 more of a difference than a five to 10 percent difference 17 that you see here, although you'd see that same difference 18 with the old source term. That's not a function of the I l 19 source term; that's just a function of the fact that the 20 leakage -- it's a leakage from containment that's held up l 21 for some number of minutes. As you slowly pressurize the 22 surrounding structure, you're going to see some delay in 23 terms of the transport off site. 24 MEMBER KRESS: What do you conclude from these ) 25 results? NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHoDE ISLAND AVE., N.W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

98 1 DR. LEAVER: Well, I guess -- let me get to a 2 ---I.have a conclusion slide. Let me -- I'll just say it. O 3 I think what I would conclude from this, though you cannot 4 conclude this would be true for every plant,.it tends to 5 suggest that when you do the whole body and thyroid dose 6 calculation, if you get acceptable results, that you 7 wouldn't expect to see dramatically different results .8 doing the TEDE. 9 Now, I.can't tell you that that will be true 10 for every plant-specific situation, but our experience is 11 that this is generally what we've seen. We saw it for 12 System 80 plus, for example. 13 MEMBER KRESS: This is justification, then, 14 for your. decision not to use the TEDE or -- 15 DR. LEAVER: That's a little bit strong, Tom. 16 I think it gives us confidence, some degree of confidence, 17 that if the regulatory requirement were to be whole body 18' and thyroid as it is today in Part 100, using the revised 19 source term, that that is still going to give you 20 reasonable assurance of adequate safety that if you were 21 to do TEDE doses that you wouldn't expect to see a big 22 difference, and so you can have as a regulatory basis the 23 whole body and thyroid dose. 24 We are, as I said, probably going to commit to () 25 submitting'the TEDE dose in addition, but we wouldn't NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234 4 33 WASHINGTON, D.C. 20005-3701 (202) 234-4433

.. _.. ~. _ _. _ 99 l 1 propose that as a. regulatory basis. We don't think you l 2 need to do that. O 3 MEMBER KRESS: This is backup information. 4 DR. LEAVER: Exactly. Backup information. 5 Just to give everybody a warm feeling. t 6 Okay. The Indian Point license amendment was 7 submitted in August of '96. 8 And the last example I have is Oyster Creek. 9' This one is in progress, and we wanted to mention it, just i 10 so you'll be aware that this is work that's being done. l l 11 The thing that I guess is most different about this i 12 application compared to the others -- this'is a BWR -f l 13 Mark I, it's an older Mark I than Browns Ferry, but it's O ' b c14 still a Mark I -- is that there are safety grade sprays in f l ^15 the drywell. And this I think is the only BWR that I know. I j. 16 of anyway that has that. i l 17 They are not currently credited for fission i 18 product removal, but they are credited for DBA heat 19 removal. 20 MEMBER POWERS: I think most of the Mark I's 21 have them. Some of them have disconnected them. l. 22 DR. LEAVER: Right. But this one we are doing 23 work now in an attempt to model this and take credit for I-24 it for fission product removal. 25 The submittal is planned for the spring of NEAL R. GROSS 1 COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 # 23 l l

100 1 '97, and the objectives in this case are to satisfy the 2 post-TMI requirement for control room habitability. ,s k) 3 That's the main driving issue here. They need to 4 demonstrate adequate control room doses, and possibly 5 increase MSIV leakage, although that's -- I don't know 6 whether they're going to be able to do that. 7 MEMBER POWERS: I'm going to hear what the 8 significance of the last sentence is. 9 DR. LEAVER: This one? 10 MEMBER POWERS: Yes. "pH controls not needed. ] 11 Essentially, no chloride bearing material in containment." 12 DR. LEAVER: Right. 13 MEMBER POWERS: What is the connection between ,n. ') 14 one and the other? 15 DR. LEAVER: The chloride -- maybe I should 16 have been more specific here, but I was just trying to 17 keep the slide brief. The chloride bearing material I'm 18 talking about is chloride bearing electrical insulation 19 cable, and it is -- it turns out it is the main source of 20 acid in an accident. And if you don't have -- if your 21 cable insulation has none of this, the whole pH control 22 issue a lot easier. 23 MEMBER POWERS: If you're using pH control to 24 prevent iodine partitioning? (\\ ) 25 DR. LEAVER: Yea. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234 4 33 WASHINGTON, D.C. 20005-3701 (202) 234-4433

? 101 ) i 1-MEMBE'R POWERS: How well does that work on ~ 1

fg 2

organic partitioning in a. radiation field? i 3 DR. LEAVER: I'm not sure what your question 4 is. The pH control -- maintaining pH really above about-5 five or six will tend to keep the I-minus that's in the l i . 6. water as I-minus. Okay? That's what is driving us to do. l 3' 7 pH control. If the I-minus goes to I-zero, then the 8 atomic form of iodine gas will partition, you will get i 9 some I2 in'the gas base. That can lead not only to' i 10 leakage of I2, but also to formation of more organic. 11-That process is not well understood. 12 But in any case, we have -- what'we are l -) l .13 generally doing in these plants is to demonstrate that we 1 14 were able to maintain pH above six or seven, so we don't 15 have-to do anything different than what is specified in-j i I 16 NUREG 1465. l 17 MEMBER POWERS: I think you want to reexamine 18 that whole business, because I think you're wrong on this. 19 I think there are two things that are going against you. 20 First of all, the radiation field obviates a lot of pH i i i 21 effect. Second of all, pH organic iodine can occur, form l 22 in solution. It doesn't have to form in the gas phase. 23 Third of all, it may not be simply a 24 partitioning of iodine from the water into the gas phase, () 25 but it, in fact, may be a process whereby you get that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 1 -. ~.

... _. _ ~ _ _ - _. _ _ _ _ _ -. _ 102 1 partitioning and then you get subsequent radiation-induced 2 reaction of the volatile iodine to form iodates that O 3 behave as aerosol particles. That reaction essentially l 4-acts like a putup, and it really doesn' t matter what the 5 partitioning coefficient is. That's just controlling the i 6 rate of partitioning. 7 DR. LEAVER: Well,_okay. We can talk about l 8 that. j 9 MEMBER POWERS: I think it's a whole lot more f i 10-complicated than just saying, "Well, we need pH6, so we l'1 can forget about this." 12 DR. LEAVER: What we have done is used the 13 information that was in 1465, which was rather general on-d 14 this subject, and much more detaile'd information that was [ 15 in-several Oak Ridge reports that were-published in the l 16 '94/'95 timeframe, to look at the formation of acids and l 17 bases during the course of the accident, and to then use .l l 18 that as a basis of looking at what the pH of the sump 19 water would be, and then from'that looking at the 20 formation of I-zero and the partitioning of iodine into i 21 the gas phase. If there are other effects that are I 22 important here, then we should look at them. 23 MEMBER POWERS: The Oak Ridge reports were -24 quite good, but they represent work _that was done i 25 substantially before the reports have been published. And NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N.W. l (202) 234-4433 WASHINGTON, D.Cc 20005-3701 (202) 234 4 33 i

103 1 there are a lot of fairly aggressive programs, especially 2 in Europe in this area, and there has just recently been a -,s / ') 3 CSNI specialist meeting on this that shows what some of 4 their codes can do in this area. 5 I think you would find some of their accident 6 analysis results really quite interesting in this regard. 7 DR. LEAVER: Okay. We'll definitely look at 8 it. Appreciate the comment. 9 Okay. Then, by way of conclusion, these four 10 bullets here, I guess part observation, part conclusion. 11 First of all, the revised source term methodology is not a 12 new thing. As I said, we stcrted in the late '80s. We've 13 done a lot of work in the context of ALWRs. Two plants \\ / 14 are proceeding to design certification using the revised m-15 source term; the System 80 plus, which already has an FDA; 16 and AP600, which is in hot pursuit of an FDA. 17 Also, we've done a lot of work on this in the l 18 context of operating plants. We think that the 19 understanding is getting pretty good. We think that the j 20 methodology is more -- really more technically accurate 21 than the existing source term. It is more mechanistic. 1 22 This does require more up-front effort on the part of the j 23 licensing and the NRC, but hopefully not more long-term 24 effort. The up-front effort would pay off, and we think ,o ( ) 25 this effort is worthwhile since it puts the whole analysis v NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433

104 1 on a much sounder basis -- a sounder technical basis, a 2 sounder regulatory basis, can be explained much more ( ) 3 readily, what we're doing and why we're doing it. 4 We think that existing regulations are 5 adequate for application to operating plants. That is, 6 the Part 100 whole body / thyroid still works fine for 7 revised source term. And we think that GDC 19, one could 8 either do whole body or TEDE, as allowed by the 9 regulations, and technically that also is sensible. We 10 think that exemptions -- our opinion is that exemptions 11 need not be required. 12 And finally, there is a need to expedite NRC 13 reviews on the pilot plant submittals, so that these plant x/ 14 improvements can be realized. And Kurt Cozens is going to 15 expand on that a little bit. 16 CHAIRMAN FONTANA: Okay. Any -- 17 DR. LEAVER: Unless there are any questions. 18 CHAIRMAN FONTANA: Do you want to take 19 questions now -- 20 DR. oAVER: Sure. 21 CHAIRMAN FONTANA: -- or do you want to wait 22 until later? Any additional questions for Dr. Leaver? I 23 guess not. 24 One thing that I would like to see at some r^x (,) 25 point is the magnitude of the effect that Dana brought up l NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 2344433 WASHINGTON, D C. 20005-3701 (202) 234-4433

105 1 -- how -- 2 DR. LEAVER: The effect of the radiation O i 3 environment on the -- ] 4 CHAIRMAN FONTANA: Yes. The -- i 5 DR. LEAVER: -- iodine? 'l i 6 CHAIRMAN FONTANA: Yes. l 7 DR. LEAVER: I'll have to look at the latest l 8 CSNI specialists' meeting -- l 9 CHAIRMAN FONTANA: So you know how -- 10 DR. LEAVER: -- results. 11 CHAIRMAN FONTANA: Yes. 12 Okay. Thanks. i 13 DR. LEAVER: Okay. Thank you. .-{ 14' MEMBER KRESS: It probably wouldn't make much 15 difference if you used the first two hours. '16 MEMBER POWERS: It won't make any difference j 17 at'all. Your iodine timing is well within the'-- if you 18 take credit for sprays, then it will make a difference. i 19 But if you don't have sprays, then in the first 24 hours 20 your iodine concentrations are totally dominated by 1- ? 21 aerosol physics. 22 MEMBER KRESS: That's right. 23 MEMBER POWERS: Unless you've got something [ 24 really active within the particles. And in some of these 25 analyses we do have to carry out 30-day dose in which the-(. l-NEAL R. GROSS COURT REPORTERS AND MANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

.. -.. - _.. _ - = - 106 l'. iodine is in everything. 2 MEMBER KRESS: I think that's where it would i l 3 show up,.in the -- i 4 MEMBER POWERS: Absolutely. The first -- 5 aerosols just are really.important, because they carry 6-such a hugh amount. But I think we just have to be.. i 7 awfully suspicious --- f 4 8 MEMBER KRESS: You have to be awfully f 9 concerned about the removal of the charcoal. filters being 10 there for other reasons. I s 11-MEMBER' POWERS: Well, I was going to say I 12. think we have to be suspicious of this pat answer and just 13 keep the pH high. I

14 MEMBER KRESS:

Yes. .15 MEMBER POWERS: Because, quit.e frankly, we 16 have a really lousy database on radiation chemistry and [. 17 agua solution at high pH. 18 MEMBER KRESS: I'll have to plead conflict of. 19 interest on that one. l 20 MEMBER POWERS: There-is no conflict of 1 21 interest on the point of information. 2: 22 (Laughter.) 23 CHAIRMAN FONTANA: Dave, I don't know if -- I 24 guess I ought to say at this point that he has jumped on 25 me for the same kind of statement. So that's -- NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.

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

- _ ~

i 107 1 (Laughter.) j t ( - 2 DR. LEAVER: Yes. He has jumped on me for l 3 things before._that -- i L 4 (Laughte'.) l r L l ~5' That's why we're here. j i 6 I 6-MR. COZENS: Can I be heard? I 7 CHAIRMAN FONTANA: Okay. Yes, I think we can ) .8 hear you.- i 9 MR. COZENS:.Let me just reintroduce myself. 11 0 I'm Kurt Cozens with NEI. 1 1 I i l 11 You've actually heard most of the punch lines 12 of what DI'll be speaking today, but let: me kind of 13. summarize some activities that we have done through the 'l 'N 14 NEI task force on revised source term and submitted'some 15 recommendations to the NRC staff, as it concerns not so 16 much the technical approach that we're taking to i 17 addressing utilization of the revised source term, but the 18 process.by which we' permit licensees to_ implement this 19 technology.. j r 20 You know, we've been working with the NRC ] i t 21 staff since about June of 19 -- was it.1994, and although-22 -- as many projects, sometimes progress is slow, sometimes i j '23 progress is fast. It's really a real concern to licensees j E24 - about the duration it will take before the industry is () 25-able to use this technology that the industry has worked i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. L '(202) 234-4433 WASHINGTON, D.C. 2000 # 3701 (202) 234-4433

108 1 l 1 so hard to develop, that has had a lot of input from j l 2 industry, and we want to look at that from a perspective 7s i \\ t 3 of, is there a way that we could expedite utilization of l 4 this new technology, the revised source term? 5 So with that in mind, let me kind of just 6 quickly review what we've heard all day. Basically, that 7 back in October the staff did indeed inform us that 8 definitely rulemaking was going to be necessary. We were 9 pleased to hear that, you know, we're at the point of 10 reconsideration of that decision, and that we're going to 11 use some additional technology to consider that. 12 Well, after having had this meeting with the 13 NRC, and going through their bases for why the rulemaking j /N k-14 would be necessary, the fact that they wanted the TEDE to 15 be used in the maximum release in a two-hour period, that 16 did not really fit within the definition of the existing 17 Part 100, was the basis for the rulemaking. Well, we 18 think there is an alternate approach to thinking about 19 that. l 20 In parallel with some of the work they are 21 planning to do, they wanted to do the baseline, which Rich i l 22 has discussed already today. And they would do the pilot 23 plant reviews, just as they have talked about them 24 previously. The real catch is the pilot plants would have ,() 25 to be approved via an exemption, a 50.12 exemption I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

109 1 believe is the -- what the staff is considering. 2 We think we can avoid having to go through 7-s, ( '! 3 looking at exemptions. Based upon the information we had l 4 back in early October, we're talking about a minimum of 12 5 months to do the baseline and pilot plants evaluation. 6 I'm pleased to see the aggressive schedule the staff is 7 indeed looking at that, you know, but we're still on the 8 same basic order of magnitude. I encourage the staff to 9 pursue the aggressive schedules. 10 But this is one of the areas that really 11 concerns us. If we go to rulemaking for this, it will be 12 three to five years from today, at least, before we would be able as an industry to take advantage of this new 13 g7 ( i x/ 14 technology. This is a concern, because there is a big gap 15 between these power plants getting approval via exemptions 16 and the rest of the industry being able to use this 17 technology. This is a lot of wasted resources that could 18 be going towards much better use in operating our power 19 plants safely. 20 So in that light, we developed some thoughts 21 on how could we take advantage of this new technology and 22 submitted a letter to the Acting Director of NRR on 23 October 28th, just a few days ago. This is -- well, I'll l l 24 call it an alternate approach, but it is really working (,) 25 within the scope of the current regulations. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

_.m 110 1 'It addresses the staff's technical concerno, 2 as Dave Leaver has just spoken about. I'm not~ going to .j i \\ '3 belabor that point too much. It addresses our concerns i i 1 4 about having to get exemptions for pilot plants. It does 5 take advantage of something that Dave had on a slide, but 6 I don't think he highlighted it. There is a precedent .l 7 already for this approach. 8 The System 80 ALWR approval -- what is it? 9 Design -- what do we call this thing? i 10 MEMBER SEALE: Design certification. l 11 MR. COZENS: Design certification and approval i 12 did take advantage of the current regulations as they are j 13 presently written on the books. They did do the whole f fs. (-) 14 body, the thyroid calculation, as the licensing basis for t i 15 their analysis. And they also provided for information a [ 16 TEDE calculation. So the approach that we've been talking 17 about has a very good example of where it has been used j i 18 before. l i 19 So we think that -- we wonder, why is this not 20 possible to be used again? And we don't see that j 21 rulemaking is going to enhance or distract from public 22 health and safety. We could still address all of the 23 technical concerns, all of the regulatory concerns, and 24 still maintain public health and safety. t 25 Now, the alternate approach that we're talking NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS - 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

111 1 about -- as Dave I think probably even better than I can 2 explain -- basically, it is a parallel set of s ( \\ 3 calculations, doing whole body and thyroid exposure 4 calculations in the zero to two-hour release, thereby 5 demonstrating regulatory compliance. 6 TEDE would done for information, TEDE 7 calculations and the maximum release in any two hours, to 8 examine the questions that the staff has indeed raised as, 9 should we be certain that we know where this really is? 10 And as Dave had indicated, there may not be a huge 11 difference in these answers. We may be on the same order 12 of magnitude. So that is the approach that we have ~ suggested to the staff in this letter that we have 13 \\' 14 submitted to them. 15 Furthermore, and I'm going to go over this 16 quickly because Dave has indeed talked to you about it 17 already, it's that GDC 19 and our reading of the 1 18 regulations does indeed presently permit TEDE. So this 19 would be an option which method the licensee would choose 20 to use. So one could demonstrate compliance with the 21 current regulations as written using TEDE or the whole 22 body / thyroid to demonstrate compliance, and then would 23 indeed submit those to the NRC staff. 24 So our letter, which we have submitted, has ,a(,) 25 indeed asked the staff to expedite the schedule. We are NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS i i 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433

..... ~ 112 1 concerned about a very long, lengthy period of time. We 2 believe there.are is alternate approach demonstrating O 3 compliance with the current regulations, and also 4 addressing technical concerns that the staff has raised. i 5-But more important, this would expedite the I 6 ability to have plant improvements and also safety 7 enhancements by moving up the time schedule for which this 8 could be done. This would be timely both for NRC and the 1 9 industry, and it expedites the schedule upon which new j 10 technology developed over many years at a great expense j 11 can indeed be implemented into the industry. 12 Let me just pick on this for a little bit 13 more. We did.an informal survey of utilities. NEI sent f~ t3 -14 out a request for information about, "Okay, utilities. 15 How many of you are really planning to use the revised 16 source term?" There was an expression of interest. We 17 received responses back from 43 plants. Of those 43 18 plants, 41 said they were interested in using the revised 19 source term. Admittedly, this is not a commitment to use 20 the revised source term right now, but it is an expression 21 of interest, and they all were pretty much interested in 22 using it in the next year or two. j i 23 Again, I-can't commit plants by saying this, 24 but there is a high degree of interest in using this new i if i-( j 25 technology. We believe there is benefits from an NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N.W. (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

113 1 operability point of view, from an economic point of view, 2 and from a safety enhancement point of view. O 3 Possibly in the future, at some later date, 4 you know, if we go through this and get into the bandwagon 5 of operating the -- of utilizing the revised source term, 6 we might suggest going to rulemaking to streamline the 7 process, but not to define the process but to use it. You 8 know? 9 There are things we could do. I'm sure I 10 could comfortably say that licensees would prefer to only 11' have to do one set of calculations versus a parallel set 12 of dual calculations. But if it takes dual calculations 13 to justify what we need to do to show that we're' safe to 14 operate, I'm sure in this environment the licensees would 15 indeed be willing to do that. 16 So possibly some time in the future we may. ) 17 consider, and would indeed support, moving towards a 18 rulemaking to streamline the process. 19 But just in summary, you know, the benefits of 20 the approach that we're suggesting that was described very 21 well by Dave illustrates regulatory compliance. It J 22 addresses the NRC staff's technical concerns. It is a 23 conservative approach. Dave has gcne into some of the 24 details of where the conservatives are, and it will permit l () 25 early plant improvements, including safety enhancements, i 4 - NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS j 1323 RHODE ISLAND AVE., N.W. I (202) 234 4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 r-

-_m m->_. ..___) 114 1~ to be implemented in a timely fashion and of benefit to j i 4 2 all concerned. I 1. - t 3 Really, this is kind of a cap on the I l-i 4 industry's entire presentation. And if you have any i e l l 5-ques *. ions, I'd be happy to answer them. i '6 CHA7dMAN FONTANA: Okay. Thanks. i. i 7 A.g questions of Mr. Cozens? f i i 8 MR. COZENS: I might -- if there are no l 2 h 9 questions, let me just ask one back to the ACRS. We are 4* - 10 presently scheduled to make a presentation at the full j. 11 committee of the ACRS tomorrow. We are, indeed, .j t 12 interested what aspects of our dual presentation you would j l ' 13 be interested in hearing about, or if there is a need at l 14 all even to present to the full committee. j i;, a i 15 CHAIRMAN FONTANA: Well, that's what we were i t l 16 going to discuss next. l 4 17 Did any of the committee members have comments j [ 18 on what should be discussed with the full committee?- i t 19 MEMBER POWERS: I guess I can't help but i~ i h 20 wonder if it is premature to expose the full committee to j i 21 this material and all of the presentations. I think.it i .i - 22 was very useful information for the subcommittee, and it -l l 2 23 looks like something that you will want to monitor via the ~ -24 subcommittee as it progresses along. j ' 25 MEMBER KRESS: As an alternative, Mario, could NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS I 1323 RHODE ISLAND AVE., N.W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

115 1 you just make a summary report to the full committee? 2 MEMBER POWERS: I would -- I think that's an fs ( ) 3 excellent suggestion. I thought that the staff 4 presentation gave a good overview to it, so that if you 5 absolutely had to have somebody speak that would be fine. 6 But a summary by Mario might be perfectly adequate at this 7 point. 8 CHAIRMAN FONTANA: Well, I'm in agreement with 9 the thrust of what all of the speakers said today, really. 10 The question is, if they have a strong feeling, if they 11 would like to -- well, the first question is, is there any 12 need for a letter? I don't think there is, unless someone 13 feels a need for one. Any industry people? I i k./ 14 MEMBER POWERS: It strikes me that it's just 15 -- I mean, we've got -- there's nothing to write a letter 16 about yet, because it's all planning. 17 CHAIRMAN FONTANA: Yes. 18 MEMBER POWERS: I mean, other than say it 19 looks like a pretty good plan, and most of the items of l 20 contention between the staff's original plans and the 21 industry seem to have been resolved. 22 CHAIRMAN FONTANA: Well, one of the questions j 23 that -- one of the questions that I had initially was the 24 need for rulemaking, and it looks like they have converged ('h () 25 some on that. NEAL R. GROSS I COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. j (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433

116 1 1 One problem that I've got with rule -- nobody 2 wants to tackle rulemaking, but how do you get rid of 3 outdated rules if no one will ever do it? 4 MEMBER POWERS: And a larger issue to look at. j l 5 (Laughter.) 6 CHAIRMAN FONTANA: Bigger than both of us, 7 right. 8 I guess I can get on my standard speech how. 9 you're still trying to patch better information on to a 10 relatively deterministic regulatory structure. It would 11 be nice if you could do a full scope PRA and really know '12 what the -- or at least have uncertainty distributions on l -13 some of these things and really know where you are ) 14 relative to -- and know what the level of -- what the s 15 margins are and make decisions on that basis. But I think 16 considering where we are now, I think you guys are doing 17-about as good as could be -- as well as could be done. 18 Well, do you feel I ought to make just a 19 review for the full committee? Or do you think they will 20 listen? 21 MEMBER KRESS: Yes. I think I share the 22 industry's view. This seems -- you know, as a l 23 subcommittee member, I am very well. satisfied with what 24 I've heard, and I can't see any need for comments or () 25 letters to anybody. Just of a summary of what we've NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE, N.W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 4

..- - -.~..- i-117 I i heard, for information purposes, from you to the full j I I 2 committee, because I think they are on the right track 3 and -- 4 CHAIRMAN FONTANA: Okay. l 5 . MEMBER KRESS: -- it's getting there. And if i-6 you see anything to give them advice on or to complain -j 7 about. 1 8' MEMBER SEALE: I guess I think it might be 9 interesting as they go through developing their. case if-L 10 they could at some-point. substantiate.the' statement that 11 what they propose is-at worst, risk neutral. ) 12 MEMBER KRESS: Yes. That's going to be L: (V 13 difficult, because a lot of the things they are talking fT 14. about doing in the way of changes to the plant design .l {

l E

'15 don't even show up in this according-to my information. j .16 So it's hard to'tell you -- to say whether it's' risk 17 neutral or not. 18 But, Mario, to qualify what I'said before, I 19 think.if the continuing discussions between'the staff and' L 20 the industry come down to a point where there is 21 disagreement.on whether or'not rulemaking is needed or .J i 22 not, then that might be a point where we might want to i 23-express an opinion at that time, f 24 CHAIRMAN FONTANA: Okay. 25 MEMBER KRESS: I think that's a real 4 3 I NEAL R. GROSS I COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 2344433

118 1 significant issue that probably our opinion of it would be 2-worth -- ~ 3 CHAIRMAN FONTANA: We do want to keep track-of 4 this issue. I guess Dana suggested doing it through the 5 mechanism of the subcommittee. When do you think might be 6

a. good time to have another subcommittee meeting to check 7

progress? 8 MEMBER SEALE: Well, I think when they have 9 something to say. 10 MEMBER POWERS: I think that dictates on their 11 progress. 12 Let me address Bob's question. I found some 13 of the things that Dave Leaver presented from the results P - 14 of the various. applications suggesting that we are very 15 close to this neutral. 16 MEMBER SEALE: Yes. 17 MEMBER POWERS: And I really might have to l l 18 give the people that developed 1465 a round of applause. 19 I didn't figure they came that.close. 20 MEMBER SEALE: Yes. Yes. 21 CHAIRMAN FONTANA: Does staff have any 22 opinions on when might be a good time for a review? Or do 23 you want to think about it and get with Jit? a 24 MR. EMCH: Rich Emch again. I liked the point 25 -- I forget who said it -- about come back when you have I NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS l 1323 RHODE ISLAND AVE., N W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 l

119 i 1 something to say. { 2-(Laughter.) e i 3 And I'm not quite sure that I can tell you i 4 what that date will be right now, but that sounds good to l l 5 me. 6 CHAIRMAN FONTANA: So Jit will stay in 7 contact, right? Right. Okay. i 8. MEMBER SEALE: And I'll be available to help i 9 drive the wagon. 10 CHAIRMAN FONTANA:.Okay, a 11 MR. EMCH: Let'me see if I understand'this. 12 We will make a presentati~on, you will present.a summary, 13 and we probably will come listen just to see if anything '14 new and exciting happens. i 15 CHAIRMAN FONTANA:. Good idea. Okay. l ~! 16 Are we done?.Okay. i 17 MR. MILLER: This is Charlie Miller. I'd like 18 t'o.make just one comment for the staff in closing and '19 reflect upon what we've heard here today, just so that no 20 one walks away with any misconception. 4 21 My comments aren't meant to try to throw cold l l-22 water on anything that was said today-by any party. But i I 23 the only caution that'I have to'be left with as a manager i 24 overseeing all of this is that there are several factors, e i 25 and there are several' steps that we.are going to go r. NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE N.W. l (202) 234-4433 WASHINGTON, D.C. 20005-3701 - (202) 234-4433 f: a

120 1 through as we do our evaluations. 2 When we talk about debate as to whether 7~ ( ) 3 rulemaking is needed or not needed, I have to remind 4 everybody that while the industry, the staff, and the ACRS 5 all may formulate an opinion on that, we have to seek 6 counsel from the Office of General Counsel, because we 7 have found that when we had those kinds of discussions 8 sometimes they had a different view than we do on the 9 literal reading of regulations. So I'd just like to make 10 sure that everybody is aware of that. 11 MEMBER SEALE: And then I think that's why I 12 suggested that if you could validate the claim of risk 13 neutrality, that might influence -- i z ( ) k/ 14 MR. MILLER: And -- 15 MEMBER SEALE: -- their perception of the 16 magnitude of what it is you're trying to do. 17 MR. MILLER: And I'd like to propose that, you 18 know, at the time that we come back and talk to the 19 subcommittee that we've had an opportunity, based upon our 20 evaluations, to have our discussion, so that when we come 21 here we'd be able to speak -- 22 MEMBER SEALE: Yes. 23 MR. MILLER: -- one voice. 24 MEMBER SEALE:

good, f3v) 25 MR. MILLER:

Secondly, I'd like to nake a NEAL R. GROSS l COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W. (202) 234-4433 WASHINGTON, D.C. 20005-3701 (202) 234 4433

~, -.. 121 '1' comment concerning schedules. Rich has put up what'he i 2 thought was our best shot at schedules at this point in 1 O 3 time, but I have to remind everyone that our schedules are 4 always subject to introduction of higher priority work. l 5 Thel staff is constantly reevaluating schedules, especially 6 when safety _significant issues come up that we are 7 heretofore unaware of, and we get those every day. l 8 I'll'just use the example of the things that 9 have gone over the past year or year and a half with 10 regard'to some of the plants in the northeast and how much l11 of the time that that occupies of the staff. So.I'm l 12 obligated to say that we have to factor all of the '13 priorities together and balance this effort versus the 14 other efforts that we're doing. Nevertheless, we plan on, 1 l .15 you know, devoting considerable resources and centinuing 16 to try to.do this to try to accommodate the schedules. .17 CHAIRMAN FONTANA: Yes. Of course, NEI did 18 ask.for as high a priority as you could reasonably -- 19 MR. MILLER: Yes. Yes. l-20 CHAIRMAN FONTANA: Okay. l l 21 MR. MILLER: Thank you. 22 CHAIRMAN FONTANA: Any additional comments? 23 If not, the meeting is adjourned. l ^ 24' (Whereupon, at 4:07 p.m., the proceedings in a 25 the foregoing matter were adjourned.) i NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS I 1323 RHODE ISLAND AVE.. N.W. (202) 2344433 WASHINGTON, D.C. 20005-3701 (202) 234-4433 l i i .l

O CERTIFICATE This is to certify that the attached proceedings before the United States Nuclear Regulatorf Commission in the matter of: Name of Proceeding: ACRS SEVERE ACCIDENTS SUBCOMMITTEE Docket Number: N/A Place of Proceeding: ROCKVILLE, MARYLAND were held as herein appears, and that this is the original transcript thereof for the file of the United States Nuclear Regulatory Commission taken by me and, thereafter reduced to typewriting by me or under the direction of the court reporting company, and that the transcript is a true and accurate record of the foregoing proceedings. I [ s IRENE GRAY Official Repo er Neal R. Gross and Co., Inc. O NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHoDE ISLAND AVENUE. NW l (202) 234-4433 WASHINGTON, D.C. 20005 (202) 234-4433

... _ _ _ m v INTRODUCTORY STATEMENT BY THE CHAIRMAN OF THE SEVERE ACCIDENTS SUBCOMMITTEE 11545 ROCKVILLE PIKE, ROOM T-2B3 ROCKVILLE, MARYLAND NOVEMBER 6, 1996 The meeting will now come to order. This is a meeting of the ACRS Subcommittee'on Severe Accidents. I am Mario Fontana, Chairman of the Subcommittee. The ACRS Members in attendance are: George Apostolakis, Thomas Kress, Dana Powers, and Robert Seale. The purpose of this meeting is to gather information on the proposed SECY Paper concerning the approval of license applications using a revised source term at operating reactors. The Subcommittee will hear from representatives of the NRC staff, the Nuclear Energy Institute (NEI), and Entergy Operations, Inc. concerning this issue. ( Amarjit "Jit" Singh is the Cognizant ACRS Staff Engineer for this meeting. The rules for participation in today's meeting have been announced as part of the notice of this meeting previously published ~in the Federal Register on October 21, 1996. A transcript of the meeting is being kept and will be made available as stated in the Federal Register Notice. It is requested that the speakers first identify themselves and speak with sufficient clarity and volume so that they can be readily heard. We have received no written comments or requests for time to make oral statements from members of the public. (Chairman's Comments-if any) We will proceed with the meeting and I call upon Mr. Emch of NRR to begin.

O O O

• l i

i i f s.. g :- l . ACRS Briefing-Staffs Plans for Implementstion i + 4: .off the1 Revised: Accident SourcejTurm e 43 attOperatingiPower'Plantsy ~ R. Emch/DRPM-NRR 4 1 l t

O O O

Background

e Final NUREG-1465 Issued in February 1995 e NEI Generic Framework Document Submitted to NRC for Review in November 1995 e NRC/NEI Meetings Held in October 1994, l June 1995, October 1995, January 1996, and l October 1996 ) e CRGR Briefing in October 1996 Commission Paper Due November 1996 l 1 U

~ O O O i Summary of StafPs Review of NEPs GFD f i t Objective is to Establish a Generic Methodology for Applying Revised Source Term at Operating Mah i l Plant Changes Classified in Four Groups i e Generic Framework Based on Four Principles i 2

o o o: 1 Summary of Staffs Review of NEPs GFD (continued) e Four Groups of Plant Changes Desired Allowable Leak Rate Changes j i Isolation Valve Timing Changes l Filtration Unit Simplification Mitigation System Actuation Timing 1 3 L

O summary or sta8s Review of GFD (continued) i 4 e Four Principles of GFD 0 Principle 1: Existing Licensing Basis is Acceptable i backfitting not required Principle 2: Complete Implementation of New Source Term as Substitute for Existing Licensing Basis is Acceptable integrated assessment needed removal of accident mitigation hardware e 4 i

O sommary or sen8s Review of GFD (continued) Principle 3: Selective Implementation of Revised Source Term is Acceptable i timing-only applications if dose calculations are necessary, j use of entire revised source term i needed j i i Principle 4: Dose Calculations Based on Existing j Methods and Limits is Acceptable i new analytical framework including TEDE and any 2-hour dose evaluation period may be necessary 5 L

~ O O O ~ AnnIvtient Framework

• Part 100 does not require a specific source term, but designed for TID-14844 1
• Current framework TID-14844 source term (1%2) first 2-hour dose evaluation period separate whole body and thyroid dose criteria I

6 h

Annivtien1 Framework (continued) e Revised Parts 50 and 100 designed for revised source term i l e Famework developed for advanced LWRs NUREG-1465 source term any worst 2-hour dose evaluation period Total Effective Dose Equivalent dose cubria P l

Possible Need for Rulemaking and Exemptions i e Phased timing of revised source term i e Existing Part 100 requires dose evaluations for 2 hours immediately following onset of release i l e Additional radionuclides in revised source term o Existing Part 100 requires evaluation of whole body and thyroid doses 8

i Rebaselinine e Evaluate BWR (Grand Gulf) and PWR (Surry) j from NUREG-1150 r i e Calculate DBA dose consequences using revised l source term 1 e Perform sensitivity studies to provide information on implementation issues l t e Scope other potential design and licensing basis impacts of possible design changes Assess severe accident impacts of possible design changes l I I;

O O O ~ k Rebaselining Sensitivity Studies i e Current plant design l i I e Effects af possible design changes j 4 e Importance offrst vs worst 2-hour dose evaluation period e Importance of whole body / thyroid dose calculation methodology vs Total Effective Dose Equivalent methodology I! 10 u

Pilot Plants l i I l e Browns Ferry (BWR) e Grand Gulf (BWR) i e Indian Point-2 (PWR) 1 e Perry (BWR) e Oyster Creek (BWR) 11 o

o o o: Staff Plans Send letter to NEI Perform rebaselining analysis Begin review of pilot plants Determine whether rulemaking and exemptions are necessary Begin rulemaking process (if needed) 12 4

~ I O O O Staff Plans (continued) i e Complete review of pilot plants and issue i license amendment (and exemptions if needed) e Prepare generic letters (if exemptions are not needed) i e Complete rulemaking (if needed) e Review follow-on applications t f 13 L

O O O i Schedule Complete rebaselining and decisions on need for rulemaking and exemptiorm 4 - Mid 1997 Complete pilot plant reviews - Late 1997 14 L

Il I i l i I ij Entergy Viewpoint on i Revised Source Term Implementation i ACRS Meetings November 6 & 7,1996 Sheri Mahoney Entergy Operations, Inc. 'nd Gulf Nuclear Station

0 0^' Overview l 1 f There are changes that are beneficial to plant safety that + cannot be made without implementing the revised source term (RST) 1 Rulemaking is not necessary - lengthy delay due to + process while current regulatory structure (SRP, Regulatory Guide,10CFR50.59) already provides a path to implement the RST 4 Rebaselining should be performed but scope of the + project should be limited i i NUREG-1465 implementation should not be delayed any + longer and should be a high priority I' ..m..

Safety Improvement Examples l l + Elimination of the automatic isolation function of selected f primary and secondary containment penetrations I Penetrations do not communicate directly with a contaminated atmosphere Ponetrations would be remote manually isolated from the control room as plant conditions dictate Provides a net safety benefit through reduced core damage frequency (IPE insight) Relaxation of the general automatic containment isolation + valve closure times Current stringent closure times add unnecessary stress to plant components Re-gearing valve actuators to allow for slower stroke times reduces component stresses and ESF electrical bus loads .m. m m

O O~' Does 10CFR100 Require a Change? I I NRC desire for rulemaking is driven by a narrow + interpretation of 10CFR100.11 which states: ...for two hours immediately following onset of the ~" postulated fission product release..." - (2-hour sliding window) "...a total radiation dose to the whole body in excess of 25 rem or a total radiation dose in excess of 300 rem to the thyroid from iodine exposure" - (use of TEDE) We believe we can address additional requirements (2- + hour sliding window, TEDE) within the current rules L

\\ o o \\ L { Current Regulatory Structure ~ (SRP/RG/10CFR50.59) I I + SRP!RG: l i f' e provide guidance on current methods require acceptance criteria for particular changes as a fraction of 10CFR100 limits i can be revised to allow an option to use the RST, includmg l TEDE and 2-hour sliding window j + 10CFR50.59: Licensees are committed in their license basis to use TID source term in dose calculations The commitments, not regulations, tie us to TID source term Commitments and license basis are changed through 10CFR50.59 evaluation I implementation of RST in this manner is consistent with + j current practice ... m - .as.c - 2 m ..m. .am-. m. .--- --ma - -- --- m.. --.. m. m

_a o 0 3 ? t Use of Rebaselining i i j NUREG-1465 does not provide all the method and + assumption details necessary to perform acceptable dose calculations; however, the EPRI Framework Document j provides important details i Rebaselining is a means for NRC to validate and improve + these details and to develop SRP guidance j 1 + Scope of rebaselining effort should be limited to establishing acceptable analytical methods and assumptions improving overall understanding of the effects of implementing the RST 1 another "research project" should be avoided p ~

O O-i i Conclusion i I In order to achieve safety benefit without undue delay, we request the ACRS to endorse early implementation of RST through 10CFR50.59 i I l i i 6 m. -mm-.o m m. m.

4 1 1 EPRl/NPG Revised Design Basis Accident Source Term 4 Methodology and Applications Presented to Advisory Committee on Reactor Safeguards Dr. David E. Leaver j Mr. James Metcalf Polestar Applied Technology,Inc. 1 i November 6,1996 i j Safety & Reliability AssessmentTarget

==' -$O ' %J EPRl/NPG Revised DBA Source Term Topics for Discussion Development of Revised DBA Source Term EPRl/NEl Framework Document on Revised Source Term for + Operating Plants Examples of Pilot Plant Applications Browns Ferry, Perry, Indian Point 2 OysterCreek l l l

==8 Sa8ety& Reliability AssessmentTarget j Page 1 i i

~t w.., 4 l EPRl/NPG l ] Development of Revised i DBA Source Term The ALWR Program (utilities, EPRI, DOE-ARSAP) initiated effort in 4 1989 i in 1p91, industry submitted to NRC two reports on a revised source a 1' term for ALWR application along with associated changes to the ALWR Utility Requirements Document NRC published draft NUREG 1465 in June,1992, and final in 1995 j-a NRC letters of July 27,1994 and September 6,1W4 indicated that the revised source term could be applied to operating plants I EPRl/NEl framework document submitted to NRC in 1995 Three pilot plant applications submitted in 1996 (and several more expected in 1997) j Safety & Reliability AssosomentTarget

==8 ~ l EPRl/NPG Status of Framework Document Objectives + + To support hoensee eWorts to apply the revtsed source term to achieve safe, cost benonceal changes to operstmg plants + To provide licensees with a consstent approach for implementation of the revised source term + To obtain NRC staff acceptance of this generic approach for implemenesson Consideration is being given by industry to updating the framework w document to reflect recent meetings with NRC staff, experience gained from recent plant speedc apphcations, and NRC staff written comments expectedin November Safety & Reliability AsseeementTarget m e=

• 5 Page 2

_ m. ( A 2 5 EPRl/NPG Updated Framework Document - Fundamental Principles m_,,.__,,_ con.uod u.c ot ine s ng de. bas. sou,ce ie,m io, a.g pianis. accepiabio (i... no backhetmg of the source term e necessary). Princana 2: (same as sustmg) Apptcaten of the mused source term as a substnute for the ommtmg er:egn base source term ' is accept.lbie based on unplementaten of NUREG 1465 and on mentaaeg adequate reguietory merge of selety. Princans 3. (same es ousteg. staff comments win be consdered) Seesctwo unplementaten of some but not an, aspecte of the feveed source term is acceptable based on acequate techncal justdinato#L Princante d- (modthod.underconseersten) in appsymg Ihe fevised source term, wnote body and thyrcai done calculatson usmg erstmg Part sco agulatory Ames de teouped by reguisten. Total seectwo does enumelent (TEDE) calculomon useg the mensmum 2 hour mierval and dose hmas in the new Part 50 rule for advanced plants should also tie provided. Princale 5: (now. under conseeration) in sopsymg me revned source term, the existmg GDC Ig requwement for control room does can be met esiher by caeuantag whole booy (5 rem) and Rs equwelent to other parts of the body or by caecuisang TEDE (5 semL Pnnants e. (now.unoor conodoraten) in espiPng me e.veed nauros inan. conswersuon shouid be een to me enegreied seiety enpact e me aspeca os me pient been.mg be enecied by me revned scure isem i aspaceaan wah aneccated pient changes. / Safety & Reliability AssessmentTarget m em

• i EPRl/NPG Principle 2 -Illustration of Margin of Safety i

LPZ Dome 4k IL m n or sway (Reguleled by NRC, RequWes Approval to Change) Uconsang Accep l tence urtwt I Does wei Revised Source f Term o Plant Delts with Revteed Source Term i 30 drys N Safety & Reliability AssessmentTarget meus e [t Page 3

EPRl/NPG Principle 4 - Existing Part 100 Dose and TEDE Existing Part 100 requirement for whole body and thyroid doses is adequate for safety and can be used with the revised source term For operating plants, whole body and thyroid doses under Part 100 are expected to be of the same order as TEDE in terms of fraction of the licensing acceptance limit Consideration is being given by industry to changing the framework document to provide a parallel offsite TEDE calculation - System 80+ precedent ]

==' Safety & Reliability AssessmentTarget O EPRl/NPG Principle 5 - Existing GDC 19 l GDC 19 states that control room doses should rd exceed *5 rem whole body, or its equivalent to any part of the body, for the duration of the accident." This is interpreted in SRP 6.4 to be 5 rem whole body,30 rem thyroid, and 30 rom beta skin over 30 days. An equally valid approach under GDC ig would be to calculate TEDE since it includes the whole body component and addresses an even more comprehensive set of organs l On this basis, TEDE is an acceptable attemative to the existing SRP dosecalculebon

=== e Safety & Reliability Assessment Target O Page 4

.. _ _. ~ _ _ _ __= 4 l 4 EPRl/NPG l Updated Framework Document - Methodology 4 For release, utilize NUREG 1465 for tim'ng, chemical form, and l release magnitude, or justify altemative. Removal methodology is addressed genierically with the main focus on airbome aerosol removal, i.e.., containment spray, natural removal in BWR drywell ano main steam lines, and BWR i pool scrubbing, j Removal methodology is intended to be reasonably conservative j such that, when combined with the NUREG 1465 releases and the conservative DBA meteorology and existing licensing acceptance limits, an overall level of conservatism comparable to l existing DBA dose analyses is maintained. j i l Safety & Reliability AssessmentTarget on==

• 4 i

J l EPRl/NPG Examples of Completed Applications - Browns Ferry Used NUREG 1465 release, timing, and chemical form l Followed industry framework document in areas not fully covered in NUREG 1465 + Drywellnaturalremoval + umited suppressen pool scrubtung h + Main steam line aerosol retention + More cunent thyroid dose conversion factors + Existing Part 100 (WB and thymid) dose calculation for EAB and LPZ Plant changes which were evaluated: + increased MSIV leakage (100 scfh per line,250 scfh total) j + Fission product holdup and retenbon in main steam lines and main condoneer (main condenser made assemic) } + No credit taken for reactor building SGTS charcoal i + No credit taken for control room emergency ventilation system (CREVS) charcoal pH control is planned and is under evaluation e 4 Safety & Reliability AssenementTarget came a T Page 5

- 4 1 .i - EPRI/NPG F Browns Ferry Dose Results 4 i Thyroid Dose (rom) Fri=rina ST Revised ST Control Room 18 17.9 1 EAB low 3.2 4 LPZ low 5.8 4 l Browns Ferry licensing amendment submitted to NRC for { approvalin January,1996 I meus a Safety & Reliability AssessmentTarget EPRl/NPG Example of Completed Applications - Perry Plant Used NUREG 1465 reloaps timing, and efammal form Followed industry frarrawork Mcunvet + Dryweli natural romoval(deposibon and sweepout) + Containtnent aerosol spray removal + Main steam line (MSL) aerosol retention + More current thyroid dose conversion factors + WB and thyroid does calculatum Plant changes factored into the analysis: + Elimination of mani steam isolaten valve (MSIV) leakage control system + Increased allowable MSIVleakage (100 scfh per kne,250 total) + Aerosol retenbon in MSL (to third isolation valve only - no condenser credd) + No credt,or annulus charcoal filter + Doley in control room recwculaten j . _ _d.,o, _,oom cha,co., + Increased allowable ESF leakage and containment bypass leakage pH control (with sodium pentaborate) is under evaluation a Safety & Reliability AssessmentTarget i m em u i O Page 6

~, __ O EPRl/NPG Perry Dose Results Thyroid Dose (rom) Frianna ST Revised ST Control Room 29.1 16.2 EAB 141 157.9 LPZ 145 130.3 Perry licensing amendment submitted to NRC for approval in August,1996 Safety & Reliability AssessmentTarget on = a EPRl/NPG Examples of Completed Applications - Indian Point 2 Used NUREG-1466 gap frechons, core snan ro6esee fractons, core damage reisees tumng, and odme chermcel form Fh mdustry framework doaament and SRP in armes not fury otwared in NUREG 1466 - Used SRP sprey removal model . increened gap reisese tracton ty 20% for acadents where long term coohng is momenned to account for Noh humup onects . Used more current thyroid does conversen factore . NW both WBahyroid does and TEDE close Plant demon changes which were induded in the revised LOCA does evalueton . Removal of postaceders swantomment fleers (HEPA and charcool) Emmmenon of sprey additNo (mcludes plant change to actuove pH estueenent by tnoodium phosphate m bookste) . Control room ventianon eyeesm mooned to pronounze the control room Safety & Reliability AssessmentTarget one= u Page 7 l 1 I t I

n O EPRl/NPG l Indian Point Dose Results j i Thyroid Doses (using current does acceptance critoria) 1 Existing Analyse. Analysis with ESAB Sf3 New Source Term Site Boundary 116 rem 180 rom 224 rem LPZ 248 rom 270 rom 147 rem CR high high 2d rem Total Effective Does Equivalent (u14ng revised dose acceptance crparla in 10CFR&J.34) Site Boundary (0-2 hr) 13.4 rem TEDE Site Boundary (worst 2 hr) 14.6 rom TEDE IP 2 license amendmers was submitted for NRC approvalin August,1996 ) Safety & Reliability AssessmentTarget on== 's N EPRl/NPG Example of Application in Progress - Oyster Creek Using NUREG 1465 release, timing, and chemical form + Following industry framework document in areas not fully covered in NUREG 1465 Drywellspray removal i + Limited suppression poolscrubbing + + Main steam line aerosol retention WB and thyroid reported for Part 100; TEDE to be reported as well + Submittal planned for March 1997 Objectives Satisfy NUREG-0737 requirement lil.D.3.4 (CR Habitability) + Possible increase in allowable MSIV leakage (based on results) + pH control may not be needed (essentially no chloride bearing matertial + in containment) on== a Safety & Reliability AssessmentTarget Page 8

y i i 4 d 'i 2 s EPRl/NPG 1 i Conclusions and Observations 4 The revised source term rnethodology has evolved considerably as part of the ALWR effort and subsequent applicaten to operstmg plants ( The rnethodology is more technically accurate (i.a., mechanistic) than the existing source term; while this requires more up front licensee effort and NRC staff effort i^ for review, this up front effort is worthwhile since it puts the source term analysis. on a sounder basse Existing regulations are adequate for application to operating plants; exemptions are not required

• There is a need to expedite NRC revows of pilot plant submittals i

Y Safety & Reliability AseeeementTarget ( Page 9 l

iiO l ih!5 l i l lMPLEMENTATION OF THE REVISED SOURCE TERM l t Presented to the O Advisory Committee on Reactor Safeguards By Kurt Cozens NEl November 6,1996 9 +

~ l 3 l 3lO NRC STAFF STATEMENTS j OCTOBER 2,1996 i 1 j Rulemaking required ) - Use TEDE and calculate maximum release in j "any" two hour period l - Technical positions differ from 10 CFR Part 100 l requirements Pilot plant applications will be reviewed j in parallel with NRC baseline studies lO - Successful pilot plant applications to be enacted via exemptions Schedule -- Approximate l - Baseline and pilot plant evaluations ) > 12 months minimum i - Rulemaking to be initiated after completion of j baseline studies and pilot plant reviews 3 to 5 years i 1 1 1 i!O d' 4 d; i

~. = _ 4 (^) APPROACH WITHOUT i RULEMAKING l 1 i i NEl letter sent to Acting Director, j NRR on October 28,1996 l Request use of alternate approach j which does not require rulemaking l - Addresses NRC technical concerns and j complies with current regulations - Pilot plant exemptions not required O - System 80+ precedent - Rulemaking is not needed to maintain public safety Perform parallel calculations for Part 100 - Whole body and thyroid; O - 2 hour release Regulatory compliance - TEDE and maximum release in "any" two hours Technical information he 2

i j C) APPROACH WITHOUT l RULEMAKING(continued) j 4 l GDC 19 allows use of either whole l body / thyroid or TEDE 5 rem whole body, or its equivalent to any part of the whole body" - TEDE considers whole body exposure and j equivalent exposure to other parts of the j body in a single summatit ' i - Licensees should select the method and will submit results that demonstrate regulatory O

• P"""*-

Encourage NRC staff to expedite 4 schedule. - Plant improvements, safety enhancements - Timely for both NRC and industry - New technology application A future rulemaking could be developed to: - Streamline the revised source term implementation process

i !O BENEFITS OF ALTERNATE i APPROACH Demonstrates regulatory compliance i Addresses NRC staff technical i concerns j It is a conservative approach . Permits early plant improvements j including safety enhancements O 4 i l i i i !O 6 i l I .}}