ML20211G678
| ML20211G678 | |
| Person / Time | |
|---|---|
| Issue date: | 09/30/1997 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-T-3011, NUDOCS 9710030187 | |
| Download: ML20211G678 (36) | |
Text
t Official Transcript of Proceedings O
NUCLEAR REGULATORY COMMISSION f CRST-SO
Title:
Advisory Committee on Reactor Safeguards Thermal Hydraulic Phenomena Subconunittee TRO4 (ACRS)
RETURN ORIGINAL Docket Number:
(not applicable) j37QE 8
415-7130 THANKS1 Location:
Rockville, Maryland O
1 Date:
Tuesday, September 30,1997 I
ACRSDificeCopy Et c
o L
Or e
re o 1:10 e o.ninii u e e Work Order No.:
NRC-1254 Pages 611-643 g oo g 7 97o930 T-3011 PDR NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Aveime, N.W.
O wa nionton, n.C. 20o0s r. i rs i n i n I (202) 234-4433 l I._ $ d 'i _i c' ~y - g Lll\\lO IiMi d.
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O DI8 CLAIMER PUBLIC NOTICE BY THE UNITED STATES NUCLEAR REGULATORY COMMISSION'S ADVISORY COMMITTEE ON REACTOR SAFEGUARDS SEPTEMBER 30, 1997 The contents of this transcript-of the proceedings of the United States Nuclear Regulatory Commission's Advisory Committee on Reactor Safeguards on J
\\
SEPTEMBER 30, 1997, as reported herein, is a record of the discussions recorded at the meeting held on the above date.
This transcrl7t has not-been reviewed, corrected and edited and it may contain inaccuracies.
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611 1
UNITED STATES OF AMERICA 2
NUCLEAR REGULATORY COMMISSION
'j x
3
++ + + +
4 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 5
THERMAL HYDRAULIC PHENOMENA SUBCOMMITTEE MEETING 6
+++ + +
7 OPEN SESSION 8
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9 TUESDAY 10 SEPT CBER 30, 1997 11
+ + + ++
12 ROCKVILLE, MARYLAND 13
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1 cm
_)
14 The subt mmittee met at the Nuclear Regulatory 15 Commission, Two White Flint North, Room T2B3, 11545 16 Rockville Pike, at S:30 a.m.,
Thomas S.
Kress, Chairman, 17 presiding.
18 COMMITTEE MEMBERS:
19 THOMAS S.
KRESS CHAIRMAN 20 MARIO H.
FONTANA MEMBER 21 DANA A.
POWERS MEMBER 22 ROBERT L.
SEALE MEMBER 23 ACRS STAFF PRESENT:
24 PAUL A.
BOEHNERT x__,)
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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ACRS CONSULTANTS PRESENT:
2 IVAN CATTON s
\\
/
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3 VIRGIL SCHROCK 4
NOVAK ZUBER 5
ALSO PRESENT:
6 ED THROM 7
JIM GRESHAM 8
DAN SPENCER 9
JOEL WOODCOCK 10 TIM ADREYCHEK 11 BILL BROWN 12 DINO SCALETTI 13 gs J
('
14 15 16 17 18 19 20 21 22 23 24 7-
)
25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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A-G-E-N-D-A 2
Attenda Item PliGE j.~)
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3 NRR Presentation, E. Throm 614 4
Subcon..nittee Caucus 625 5
6 7
8 9
10 11 12 13
,s 5
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't.J 14 15 16 17 18 19 20 21 22 23 24
/~ ~'N 25
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P-R-O-C-E-E-D-I-N-G-S 2
7-s (3:35 p.m.)
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3 CHAIRMAN KRESS:
We always seem to be rushed 4
when we get to your part.
We're going to have to -- oh, 5
yes, we are now back in open session, if anybody is 6
interested.
7 MR. THROM:
Again, my name is Edward Throm, 8
I'm with the Containment Systems and Severe Accident 9
Branch.
And we were going to make some general comments 10 on what we think about PIRT scaling applications report.
11 Be aware that at the working level, about once every two 12 weeks the staff has been getting a submittal from I
13 Westinghouse on this project, and that's been for the last N,_)'
14 two years.
So there's a lot more interaction going on 15 than comes out in the documentation, and that's been a 16 problem, and we're seeing a lot of that today.
4 17 In terms of the latest PIRT report, we think 18 that the information in there is sufficient for us to 19 review and evaluate the rankings.
We think that the 20 expert panel information is not as good as it could be, 21 and we are factoring what we think it is into the review 22 process.
We don't think it's going to be a stumbling 23 blocP.
24 CRAIRMAN KRESS:
You're making your own rx
()
25 judgments as to the ranking, is that what you're saying?
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_ _ _ ~
615 1
MR. THROM:
Yeah, in the overall process.
The 2
question is, which expert was the one who disagreed, and
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3 how that gets involved in the process.
I don't believe 4
we've seen any case where we disagree more than one 5
ranking level between where a phenomena is so, you know, 6
we have similar impressions about what was done with the 7
peer review.
It's part of the process.
It's not going to 8
be a major process in identifying or looking at the 9
ranking of the phenomena.
The real question is, are all 10 the phenomena properly addressed in the report and in the 11 evaluation model?
12 The scaling report has gotten a little better.
l l
13 We've spent a lot of time reviewing it.
We did miss the
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4
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14 CVCP derivative aspect of it, and we need to look at that 15 again.
16 MR. ZUBER:
In fact, if you do this, you will 17 find out that the pressure, the turn down normalizing that 18 equation, the meter does not even appear in that equation.
19 That's a fictitious meter.
20 MR. THROM:
We understand that, yes.
21 The role of the LST, we think it's getting 22 clearer.
We don't think the documentation necessarily 23 does it.
And, again, I think this is more involvement on 24 a daily basis that we have with Westinghouse.
We're
,m()
25 expecting to get a much better definitive role of the LST, NEAL R. GROSS COURT HEPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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where and when and how it can be used.
And that's still s
2 an evolving process.
k) 3 We understand the difference between the work 4
done in the scaling which is, for lack of a better 5
expression, a best-estimate evaluation of the transient 6
versus the evaluation model.
7 The mass and heat transfer relationships from 8
the literature, Colburn-McAdams, which Westinghouse are 9
using, have been demonstrated to cover the range of the 10 AP-600.
And you've seen what they do to try to bias that 11 information.
That's what we mean by putting some 12 conservatism into the evaluation model.
Within the context of the applications report, 13 x-)
14 which is the thing that we'll be discussing more in 15 December. there are a lot of sensitivity studies in that 16 report that kind of validate the assumptions that are 17 being made to establish conservative conditions.
18 There's an assumption made by Westinghouse on 19 the steel jacketed concrete, which has an impact on the 20 problem, and they are looking at a 5 mil gap between steel 21 jacket and the concrete.
22 The construction of the AP-600 is quite 23 different.
It's an important factor if one really looks 24 at the possible impact of a larger gap and meeting the
,~
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25 design requirement.
We're looking right now at i
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establishing a mechanism to say that the construction 2
technique and the kind of concrete that's going to be (n) 3 selected for the AP-600 can lead you to believe that you 4
can obtain that type of a goal in this construction.
5 As has been indicated, Westinghouse is using 6
Uchida correlation for heat structures other than the PCS.
7 There's been some discussion of the way they treat heat 8
transfer surfaces, for example, neglecting heat transfer 9
surfaces on upward facing floors where films might 10 accumulate.
That's part of the evaluation model.
11 The PCS shell was handled with the Clime 12 model, and the correlations that are being used have been 13 shown to be representative of the LST and the Wisconsin (3
Y.
14 data.
15 And the external coverage fractions to 16 generate the water coverage model will be discussed more 17 in the December time frame, and the effects of what is 18 called 2-D conduction will be also discussed more in the 19 December time frame.
These are discussed in Section 7 of 20 the Applications Report and, when you get into the section 21 on the 2D conduction that Westinghouse is loo!.ing at for 22 the long-term performance, you'll see a much better 23 description of the machine, how the weir distribution 4
24 distributes the water and the water distribution test (N,
()
25 showing the coverage fractions for the given sets of flow NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE, N.W.
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rates.
They are important parts of understunding the way 2
the machine behaves.
)
3 CHAIRMAN KRESS:
Thus is 2D conduction in the 4
shell itself?
5 MR. THROM:
Yes.
In the long-term, the water 6
is going to develop into stripes.
During the first three 7
hours, you've essentially got 90 percent or 100 percent 8
coverage.
When you get down to the real long-term, you 9
may have something on the order of 50 percent or less of 10 the shell being covered.
11 Well, in the real world, there will be 12 conduction from the dry, hot shell into the water, and 13 this is something that Westinghouse would need if they n
i' s/
14 really wanted to meet the one-half pressure limit.
We've 15 had discussions with Westinghouse NRC Senier Managers.
16 It's not a regulatory requirement, so we're still looking 17 at what to do with that.
And this is something that 18 showed up in the process late May of this year.
19 CHAIRMAN KRESS:
They don't need it for the 20 peak?
21 MR. THROM:
No, no.
The peak occurring at 22 1200 seconds, full flow on the system is delivered for 23 about the first three hours, so there's really two 24 separate problems to be addressed.
There's the peak F '),
25 pressure and then there's the long-term performance of the t
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machine.
As I indicated yesterday, demonstration of
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pressure reduction is not required for their siting i
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3 evaluation.
They do their siting evaluation on a very 4
conservative basis, assuming no pressure reduction.
5 And the last remark on there is something 6
that's been discussed here, and it's the Chun and Seban 7
correlation for wavy laminar flow and how it's being used 8
to evaluate the effective thermal resistance of the film, 9
and whether films are thick, thin, or in between, and 10 there's a big difference between what's done in the 11 scaling and what's done in the AP-600 and WGOTHIO.
12 Hopefully that will be clarified in December.
13 Outstanding issues and concerns.
I think we
)
\\_/
14 agree that the largest concern right now is with the 15 condensation on the shell, and I guess there is still some 16 misunderstanding about what the process is.
We think 17 Westinghouse has been looking at vertical stratification 18 and missing the point is, how is the steam migrating from 19 the center of the containment into the shell?
I look at 20 it as the steam migration, you look at it as the air 21 buildup.
It's the same thing.
22 We think that's kind of what's missing in the 23 story right now.
We're looking at Chapter 9 to see if 24 that's answering that question.
,r
,( j) 25 MR. CATTON:
That brief analysis that they NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE, N W.
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showed is based on the plume begins to get at the s
2 question.
You determine the air circulation, the steam is p
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l 3I being carried with it, and where is the steam going?
4 MR. THROM:
Right.
At this point, we're at 5
the same place you are ta that situation, and it's not 6
whether it's 90 percent in the top and 20 percent in the 7
bottom, it's how is this migrating towards the surface, 8
and how is that boundary condition -- it's the delta 9
rho / rho.
Are the bulk properties that they're getting out 10 of WGOTHIC the right ones to be using for the analysis.
11 MR. CATTON:
If that plume analysis has any 22 credibility at all, 99 percent or whatever in the top is 13 ridiculous because, if you have this tremendous
,a
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14 entrainment, you're going to be reducing it way down 15 before -- relative to what the ambient is way before you 16 get to the top.
17 MR. THROM:
Right.
18 MR. CATTON:
And something realistic should be 19 chosen if they want a free zone model, not a 99 percent --
20 99 percent is going to cause more headaches than it's 21 worth.
22 MR. THROM:
I agree.
Whenever one does a 23 sensitivity study, there should be a real argument for why 24 it's a reasonable sensitivity study and --
n i
I 25 MR. CATTON:
And it should start from your V
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best shot at what you think it is, and then range it.
s 2
MR. THROM:
Right.
Heat sink utilization, t
3 What Westinghouse is referring to on heat sink utilization 4
-- and it's an issue with the scaling report, where the 5
conclusion is heat sinko aren't very important during 6
blowdown, but that's a relative measure as to who is more 7
important during blowdown, gas compliance or heat sinks.
8 The heat sinks are important and they do consider them 9
during the initial blowdown, but then effectively they 10 turn them off after that period.
11 It's something that on the surface appears to 12 be conservative.
We're still looking at it more or less 13 in terms of validating it or confirming that it's not (3
(_ l 14 doing something later on in the transient that's 15 unexpected, and it kind of impacts the way one would look 16 at the lumped-parameter model that's being used to 17 represent the AP-600.
18 Westinghouse is relying quite a bit on the 19 EPRI GOTHIC qualification database.
It's our belief and 20 Westinghouse..as stated that if you were to look at any of 21 the international programs that were done with GOTHIC on 22 the order of version 4.0, Westinghouse's WGOTHIC would 23 give you the identical result because the only thing they 24 have done to GOTHIC to create WGOTHIC, as I said (nl 25 yesterday, is to add the P_S as a different heat J
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structure.
2 So, if you're looking at the lumped-parameter 7s
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3 characterization or calculation of things like NUPEC or 4
HDR, and you looked at some international calculation with 5
GOTHIC of that, it would be representative of what 6
Westinghouse is trying to do, but Westinghouse hasn't 7
really created those models other the.n NUPEC, and the 8
lumped-parameter model that Westinghouse uses is rather 9
unique in the context of what's available in the 10 international database, particularly the modeling of the 11 above-deck region.
There is an extreme amount of detail 12 up there which will influence the way the code behaves l
13 even in a lumped-parameter fashion.
And we're working on p
(/
14 getting to some closure on understanding the 15 characterization that they have of that model.
16 So, to repeat again, Westinghouse has 17 conservatively addressed the mass and heat transfer, but 18 the approach does not really the distribution of 19 noncondensibles, which is the issue I just talked about 20 earlier.
And there is the need to address the potential 21 distortions of that lumped-parameter nec rk.
And there 22 are a lot of questions out on that, and a lot of answers 23 have come in and we are in the process of trying to 24 understand that and make sure their lumped-parameter 7m
(
)
25 overall approach is not creating any additional NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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1 distortions in the process.
2 And the other outstanding issue is the 7c3
('-)
3 evaporated flow model, which needs some validation.
It's 4
an external calculation, as they've indicated, which 5
basically tries to limit the amount of water that's 6
credited in the evaluation only to what's expected to 7
evaporate.
And it also attempts to correct for the change 8
in the area coverage as the water flow rate changes, but 9
the way they apply it is a little different in the 10 analytical sense than what we think is the true 11 characterization in the real world, and we're still 12 reviewing that particular issue.
13 And in terms of review schedule, from a date
/~N (ss) 14 right now, my understanding from the projects on is we're 15 trying to get an evaluation completed by the end of this 16 calendar year, the end of December.
17 The things we're working on right now is 18 within the context of the PIRT report, to assure that 19 there's closure or consistency between what the high-20 medium rank phenomena are, and the address them in the 21 Applications Report.
22 In the Scaling Report, the conservatism of the 23 mass and heat transfer, particularly the effects of the 24 scale on the bulk conditions.
Again, this is the running A
(
)
25 thread that we've had in really these two days.
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1 the Applications Report, it's understanding the lumped-f(o) 2 paramet3r nodalization effects on circulation and 3
stratification, and how the heat sinks are being treated, 4
and whether or not there 10 something unexpected in what 5
appears to be a conservative approach in the long-term 6
overall performance of the analysis, and the water 7
coverage model and the 2D conduction assessment that 0
Westinghouse is using for the long-term, and the long-term 9
is out past the three hours -- actually, out past the 24-10 hour time range.
11 That's pretty much all I have to say today.
12 In terms of Westinghouse's presentation, I hope it has 13 provided a road map to where the information is, and that V
14 we'll have an opportunity to really go over the water 15 coverage and the circulation stratification issue, and 16 hopefully come to closure on the real big question on 17 whether or not we agree that the bulk conditions that are 18 going into calculating the condensation are appropriate 13 for the licensing of the AP-600.
20 CHAIRMAN KRESS:
That's basically the same 21 iasue we have.
22 MR. THROM:
Yes.
I mear., I prepared these 23 slides last Friday, believe me or not, but that's pretty 24 much where we are.
It's very similar to the concern.
/'~~N
(
)
25 CHAIRMAN KRESS:
Okay.
At this point, I'm NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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going to ask the consultants if they would like to make 2
some closing comments, and I think I'll start with Ivan 7_
3 and just work my way down.
4 MR. CATTON:
Okay.
One of the things that 5
they asked -- that we were asked was, what topics for 6
Decc mbe r, and I just sort of tried to lay something out.
7 During the presentations, it often got kind of a
confusing as to just what we were talking about and what 9
phase.
1 think a clear delineation of the phase of the 10 action and what we'll be looking at.
And I think we've 11 already pretty much agreed that it should be from the 12 blowdown peak, at least as far as I'm concerned, a little 13 ways past the second peak.
I mean, once it's on the 5%-)
14 downhill slope, I don't think it's a safety issue, it's a 15 different kind of issue.
16 Second, I think the various circumstances that 17 need to be looked at, like source location -- the damn 18 source location moved all ever the place.
Sometimes it 19 was under the deck, sometimes it up above, and you lose 20 the connection between source location and what we're 21 talking about.
And often when we would ask a question, 22 the source location would move.
23 I would like to see the source location fixed, 24 we talk about it, eliminate it, new source location, if O) 25 the source location is important, so that we can keep it i%d NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE, N W.
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straight what we're talking about.
2 A better description of the basis for the
']
3 correlations for heat and mass transfer -- now, maybe when 4
I read the document that I'm going to get, this doesn't 5
need to be very much -- and the description should include 6
the tests with helium.
I didn't like what I read about 7
those tests.
8 Fourth, the basis for the use of lumped-9 parameter model', and here it gets to the question that Ed 10 put up, how are 9.adient governed transport processes 11 treated within a lumped-parameter framework -- basically, 12 that's the question.
13 And then I think, finally, some results
(~)
(l 14 showing sensitivity to the various parameters that are s
15 somewhat uncertain.
You talk about bounding.
Well, if 16 you're going to bound, show us what the bounding is doing.
17 If you have a particular parameter, range it up and down.
18 What does it do?
This should include the basis for the 19 ranking of parameters chosen.
A simple model might be a 20 good tool to help select the parameter ranges.
And I'm 21 referring to the model that was presented that showed the 22 plume and so forth.
23 Just to reiterate my concerns, first, too many 24 conclusions are drawn to get reference to LST as their (m) 25 basis.
I don't believe the LST scaling analysis is robust v
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enough to be ccnvincing.
You'll notice I'm not going to 2
say that it's wrong, it may be just part of it is missing.
,- s
(
)
\\#
3 And I think the problem is too much energy and 4
mass per unit volume and, because this is what stirs the 5
volume, that's an important parameter, in my view.
If you 6
wanted to get an exact similitude, there are a lot of 7
these things that you'd have to include.
Buoyancy added 8
is important.
The amount of momentum added is important.
9 And all of these things should be per unit volume because 10 it's the volume that we're concerned about.
The volume of 11 gas is what's going to dictate the pressure.
12 I think the correlations, at least at present, 13 appear to be reasonable.
The problem is, they require ONJ 14 free stream conditions, and a lumped-parameter code is not 15 the tool to obtain values of the free stream for boundary 16 layers.
17 I don't know how you're going to get around 18 this, but you're going to explain it to us in December.
I 19 think that's all, Tom, and what I'll do is, in the report, 20 I'll give some details about my views et the two reporte 21 that we read in preparation for this meeting.
22 CHAIRMAN KRESS:
Very good, I would appreciate 23 taat.
And, you know, if you could get those a couple of 24 weeks before our December meeting, we could pass them on.
~/N(v) 25 MR. CATTON:
Well, what I'm hoping is that I NEAL R. GROSS COURT REPORTERS AMD TRANSCRIBERS 1323 RHODE ISLAhD AVE., N W.
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can get them in the next week or so.
2 CHAIRMAN KRESS:
Okay, that would be great.
/
s
3 MR. CATTON:
And I'll also include my 4
simplistic -- what I sent you earlier, the simplistic view 5
of the first law of thermodynamics that clearly shows the 6
A/V, after I correct the equations in the onc I sent you.
7 CHAIRMAN KRESFt I wish you would make an 8
analysis that convinces you that energy put in is less per 9
unit volume rather than more for LST, so that you can get 10 that part. straight.
11 MR. CATTON:
Okay.
12 CHAIRMAN KRESS:
Virgil?
13 MR. SCHROCK:
I guess I don't really know what
/~h
(-)
14 to say, Tom.
The amount of confusion that I found was 15 sometimes a little overwhelming, but there were some 16 positive things that came out here.
This road map, I 17 think, is certainly helpful, and it will be more helpful 18 when we receive a copy that's legible enough to read all 19 the subscripts and so forth, so we'll be looking forward 20 to getting that, I hope in advance of the December 21 meeting.
22 I think that Spencer's simplified plume 23 analysis is very interesting, and just a tremendous 24 mystery to me as to how, knowing what Westinghouse knows
)
)
25 about that, they come up with a bounding situation which
%/
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flies in the face of what they learned from that.
Mavbo 2
we'll understand more why they do that when we see all of
,s
(
)
3 the evidence in December.
4 There are just too many ways in which things 5
that we've questioned as we tried to discuss our 6
interpretation of what we read in the PIRT scaling reports 7
that somehow depend upon 14407 answers, that couldn't be 8
provided, or wouldn't be provided, and it seemed to me 9
that in some cases it was just the insistence that we 10 don't have time, or we won't today, but I felt a good deal 11 of frustration owing to the fact that I don't think we 12 were communicating well in this meeting.
We've wasted a 13 lot of time owing to this.
,p
(,,)
14 I won't lay blame someplace, but I think that 15 unless there's a major change in that for the meetings in 16 December, the days that we meet in December, it's not 17 going to result in a statement or any kind of 18 recommendation from me at the end that the thing looks 19 like it's wrapped up.
I feel quite a ways from that 20 today, and I think a lot has to happen in the time between 21 now and the meeting in December, together with what we 22 learn in December, in order to make that possible for me.
23 I thought that I heard that Westinghouse was 24 acknowledging that LST data are not suitable for
(
j 25 interpreting the scale up to AP-600, but then in the end NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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it seems like that got turned around, so I'm confused as to where Westinghouse really is about what they think 2
I 3
about their LST data as a basis for establishing biases 4
for the evaluation model.
5 Apart from that, there were some errors that I 6
referred to in my opening remark, and I'll document that 7
part. I think there is one document at least that I don't 8
have as yet, that 9
MR. BOEHNERT:
At least one.
10 MR. CATTCN:
Heat and mass transfer report.
11 MR. SCHROCK:
-- heat and mass transfer 12 report, right.
13 MR. CATTON:
Tom, I have one more thing before
/'~'
(._,N l
14 Novak.
15 CHAIRMAN KRESS:
Okay, go ahead.
16 MR. CATTON:
In that our consultant reports 17 are going to go to Westinghouse, maybe we could ask 18 Westinghouse to help us, and that would be a list of the 19 relevant references and what they should tell me, so that 20 I can then lay all this out and start walking my way 21 through it before we go to the meeting in December.
And 22 by re?evant, I mean those that they think should convince 23 me that they have the circulation and.tixing well in hand.
24 I mean, there's a lot of this unpublished (m) 25 thesis or draft thesis stuff, all these kinds of things NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE lSt.AND AVE., N W.
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l 1
floating around.
I think Westinghouse should supply the 2
relevant references if they are not available in the open
\\ ' ')
3 literature.
So, if they could somehow put this package 4
together, tell me how this makes their case, then you can 5
come to a better conclusion.
6 CHAIRMAN KRESS:
That may be a lot more than 7
you want.
8 (Laughter.)
9 MR. SCHROCK:
It probably is.
10 MR. CATTON:
Well, you know what G.E. did when 11 I made this kind of request, they sent me a thousand 12 pounds to my office.
13 CHAIRMAN KRESS:
That's why I cringed.
(x i
1
(/
14 Anyw*y, this is something that we can discuss with 15 West.nghouse, it's not something we can resolve here.
16 MR. CATTON:
I understand.
It just would be 17 helpful, and it would eliminate a lot of the difficulties 18 we've had.
19 CHAIRMAN KRESS:
Maybe just some of the key 20 ones you might need.
21 MR. CATTON:
Yes.
22 CHAIRMAN KRESS:
So we'll take that up later.
23 Novak, we'd like to hear from you now.
24 MR. ZUBER:
I've spoke enough.
I shall try to (x) 25 be positive in the beginning, a little bit critical in the NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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middle, and be positive at the end.
fs 2
CHAIRMAN KRESS:
Okay.
The sandwich approach.
T 3
MR. ZUBER:
So, bear with me.
Let me -- I 4
shall address four topics -- first will be scaling; two 5
will be LST; three, bonding calculations and, finally, my 6
recommendations, and I think the job can be done and could 7
be defended.
8 First, I would like to -- I see no problem.
I 9
think this document acceptable.
There are minor lo questions, but I think, as is, I am quite happy with it.
11 I also would like to compliment Westinghouse 12 for providing this on short notice.
It's helpful.
I 13 think once you update it and put it in a report with an
.n) 14 executive summary, one can then really follow it, it will s._
15 he very helpful.
And, again, thank you for a fast 16 response.
17 Now we come to the sticky part, scaling.
And 18 I was once upon a time a professor and later on I was also 19 a member of NRC, so let me address this report on two 20 levels, first as a professor -- ex-professor.
21 If a student came with this report to me for 22 their Master's or Ph.D.,
I would really question the basic 23 aspect of mathematics and thermodynamics and fluid 24 mechanics on the junior level.
I think this report shows
( )
25 really something which is patently wrong.
I think this NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISt.AND AVE., H W.
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was pointed by Virgil.
2 I think the discussion when I was reading the
,y
(
)
3 report-how the pressure was scaled, the report says it was 4
scaled up to the inflection point and, during the 5
discuscion here, we found it was not inflection point, it 6
was the maximum point, but that's basic mathematics, 7
Calculus 1-A.
8 The scaling, I think, is wrong.
I think the 9
force which was used to normalize does not appear if it's 10 done correctly, it's a fictitious force and, therefore, 11 based on that, based on these errors, I really find the 12 report meaningless.
I could not defend it, and if this 13 was a thesis, I would not accept it.
And I would say to p'_/
14 the student, go back home and redo it.
And it can be i
\\
15 done.
16 Now, if I was NRC and reviewing it, I would l's make the same comment as a professor, and I would tell to 18 them that many of the comments which are made addressing 19 the bias really was arm-waving.
And what I really found 20 to be useful -- and I saw Graph 11.1 in the report, 21 listing all the distortions -- I said, that's fine, but 22 then when I looked at the justification later on, it was 23 just plain arm-waving.
24 So, they identified the problems, but then o
(
)
25 didn't really give me something I can agree.
It was just
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something which I believe in this and you believe in that.
2 So, let me say, as much as I would like -- and s
3 believe me, I would like to have signed off on this report 4
-- I could not accept it either as an ex-Prcfessor or NRC.
5 I would not be able to defend it in any way.
6 Now, what can be done?
One could do a top-7 down scaling, identify the important contributors, go 8
down, ask how the mixing is accomplished, or how do I 9
model it?
This can be done.
10 I think a first step would be to do a correct 11 top-down scaling.
Second step is then to identify the 12 effect of the plumes, the effect on this mixing.
The 13 first step was done, demonstrated by -- and I was really
(~');
(_
14 surprised, I was really surprised -- pleasantly surprised.
15 First, I was frustrated with the arm-waving on the 16 bounding calculations.
Then I saw there is an approach 17 these people realized, and I was surprised why this 18 approach was not adopted from the first meeting a few 19 years ago.
The thing can be done, and I hope they will do 20 it.
21 LST.
LST, I have no problem, as long as you 22 don't have heat losses.
I think during the blowdown 23 period that's a balloon problem, and that's fine.
The 24 critical thing which LST is not get bubble, at least on
/
\\
t,
)
25 the results I have seen to be useful, is between the two s-NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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peaks, between 30 seconds and let's say 5,000 seconds.
I 7-2 think this is the critical window, and it was not
\\
3 addressed in a way one could be able to evaluate a 4
response.
5 The energy in the beginning was too small, 6
removal was too high, so that whole region is really 7
questionable.
I think that facility can be used in 8
conjunction with top-down scaling which you can defend and 9
in terms of these plumes and mechanism.
You can devise 10 several models, look in the literature what's supporting 11 evidence, and run few tests with the LST just to confirm, 12 and it can be done.
And I'm really sad, really 13 frustrated, sometimes sad, that this was not done because
,G a
x_/
14 the facility is there and the comments which were made 15 were really made several years ago.
16 Now, if this is done from the top-down and 17 bottom-up scaling, and maybe some tests -- this requires 18 time I don't think it can be done between from now to 19 December because looking at my first experience, this was 20 not done during the five years since 1952 when I went to 21 Pittsburgh.
22 What I would really like to do -- to make --
23 and I really sympathize with NRR because they are under 24 pressure to have it approved.
Westinghouse would like to
,n 25 have it approved by December, and I don't see how this can v
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be done in a defensible way.
I'm afraid that in December 2
we shall hear again beliefs and religions, maybe it will 3
be better understanding, but we won't be able to close 4
this issue.
5 And I have a strong recommendation.
I think 6
the idea came from Ireland.
And this would be as follows.
7 I would recommend that Westinghouse, if they want to have 8
a certification by December, put a safety grade sprinkler 9
in the vessel, the way we have done before, so there is 10 not much more to be approved there.
We have this 11 technology, it can be approved.
12 So, the emphasis on the Swedish safety grade 13 system could really be approved by December, more or less.
x' 14 This would satisfy Westinghouse's desire to have it 15 approved. This would also give something that NRR can live 16 with and, if we approve it, we can live with it.
As a 17 technical matter, I could not say this is good work 18 because I could not defend it.
19 So, this would buy some time.
Westinghouse is 20 not going to sell the plant in the next six months or a 21 year.
During that time, they can perform a nice analysis 22 on the scaling plumes with some experiments, maybe six 23 months, no more than a year, eight months, I think between 24 now and June, if you do some thinking, and we could maybe
<~8()
25 have some preliminary discussions with this committee how NEAl. R. GROSS CoVRT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE, N W.
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to do it or that we understand what you want to do, you 2
get our comments, you get comments from other people, this
\\
)
U 3
could be done.
4 Then by June, you should have a good database.
5 You can defend your mixing thing and you could defend you l
6 control volume approach in the court.
And you would have 7
a database to defend it.
Then you could come back and a
say, I have a defensible model.
This condensation 9
approach is good.
This new facility is fine.
And then 10 you don't even have to have this s'.fety grade sprinkler.
11 What you are really buying is time.
You are getting a 12 certificate for something which you are already 13 comfortable with.
You are buying time for eight months, l'
b V
14 no more than a year, to do a good defensible technical 15 job.
That would be my recoumendation.
16 I don't think that we can have this thing put 17 to rest by December.
We didn't do it in five years.
I 18 don't want to delude myself that this will be done, as 19 much as I would like.
I shall send you a report on that 20 and my comments on these equations.
And let me say, I a
j 21 apologize to ACRS and my colleagues here if I sometimes 22 lost my temper, and I was frustrated. I think I should not 23 have called George Yadirarouglu Professor Yadirarouglu, 24 but I was sometimes frustrated because the thing can be
{3) 25 done, and was sad that it was not done.
So, that's all I
(
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have to say.
2 CHAIRMAN KRESS:
I wish to thank the i
\\
3 consultants for their comments.
I will give the 4
opportunity to any of those subcommittee members to say 5
anything they'd like.
I don't think it's necessary.
We 6
discussed these in full committee, but if anyone wishes 7
to, why, I'll hold the floor open.
8 MEMBER POWERS:
I feel an obligation to say 9
something since I'm new to these meetings, and I thank the l
10 committee for asking me to attend.
And I just wanted to 11 compliment Westinghouse on what I thought was a tremendous 12 presentation and obviously a huge amount of work, and just 13 say that I think you have helped me in prnviding a
,o,
)
(_/
14 guidance to all the documents that have suddenly shown up 15 on my door.
I think I'll be able to read tnem much more 16 effectively than otherwise I would have, and think you 17 should be complimented on scmc very nice presentations.
18 MEMBER SEALE:
The LOCA to the main steamline 19 break are surrogates, or what are conaidered to be 20 appropriate safety challenges to the system.
That doesn't 21 mean they are the only thing that can happen -- indeed, we 22 have experience in other areas where we've tended to focus 23 too sharply on one particular thing to our later grief.
24 The problem, it strikes me, is that I can
(
)
25 think of situations where the mixing which seems to be the
%./
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crux of so much of the discussion about the behavior of 2
the system won't be as vigorous because the leak isn't s
3 that large, and yet with time you certainly could get some 4
stratification in the system.
5 And I'm just worried -- I would like to be l
6 reassured that under those circumstances, the system with l
7 the degradation that comes with the development of 8
stratification and then perhaps post to that an increase 9
in the rate at which the heat load is coming in, that that 10 system can handle the problem.
11 Now, that's the kind of thing I'm worried 12 about some, and I'd like to hear a little bit more about 13 how sanguine we are about the ability of this system to be
/h
\\
(V 14 mixed.
That's beating a horse that's already got a lot of 15 lash marks on him, but he probably deserves another whack 16 or two.
17 MR, CATTON:
So, Bob, what you're interested 18 in maybe would be a ranging of the break size, 19 MEMBER SEALE:
Yes.
The other thing that's --
20 and at this point, following up on what Dr. Zuber said, I 21 have to say that that spray system sure does seem to be 22 handy.
So, those are my comments.
23 MR. ZUBER:
It can be certified on that, and 24 they buy a year and --
(-()
25 MEMBER SEALE:
Even if it's not certified, for NEAL R. GROSS COURT REPORTERS AND TRANSCR$tRS 1323 RHODE ISLAND AVC., N W.
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that size problem it sure is handy to hava it around.
2 MR. CATTON:
And they can taku it out if they
<-)
\\
)
3 don't like it, if they can demonstrate they cen't need it.
4 CilAIRMAN KRESS:
Mario, you're welcome to 5
comment.
6 MEMBER FONTANA:
Well, I'm fairly new to these I
7 meetings, and it appears there's a tremendous work has l
8 been done, and there's been a lot of discussion about the 9
glass being partly empty, but the glass is partly full.
10 There's a tremendous amount of work that hasn't been done, 11 and it appears to me that not much more has to be done 12 compared to what hao been done, to get this thing over the 13 hill.
But I tend to agree with the consultants over t'%
(.
14 there, and I think it doesn't look like it's going to get 15 done by December.
But I want to commend Westinghouse for 16 a tremendous amount of work, and the next time they come 17 in possibly it could be presented in a more linear, easy 18 to understand way, but I look forward to that.
19 CllAIRMAN KRESS:
I will remind everyone that I 20 will have the enviable task of giving a subcommittee 21 report to the full committee at the end of this week, so I 22 will reserve my comments until then.
23 I do want to say one thing, that I think the 24 plume model that was presented is only a start on
/
i
)
25 evaluating the effects of mixing.
A lot more than that NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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needs to be done.
I mean, I think I made this point 2
earlier, that I don't think it gives you the complete (U) 3 story, but it is the right approach to begin starting.
4 It has to be carried further, and it has to be 5
carried to the downward plume that comes down the wall and 6
the effect on the distribution, on a continuing process as 7
thin plume developa into some sort of transient 8
distribution.
9 So, I think more, a lot more is needed than l
10 just this plume, and I think you have to add some of the 11 energy equations into it.
But given that, I will give 12 Westinghouse a chance to have the last word, if anyone 13 would like to make a comment before we adjourn.
V' 14 MR. VIJUK:
Just one question.
I assume the 15 recommendation on the spray deals with mixing -- the basis 16 for recommending a spray?
17 MR. ZUBER:
The point is, I don't think you 18 can really show by December --
19 MR. VIJUK:
Yes, I understand that, but what's 20 the objective of the spray, the mix?
21 MR. ZUBER:
Oh, the spray.
Since you are not 22 sure that you have had the condensation, you want to use 23 the licensing basis the way we have done before, so you
~. 4 don't have to go through this argument.
And you don't
,m
(
)
25 depend on the water coverage outside, you don't depend on v
N EAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE-. N W (202) 234 4433 WASHINGTON. D C. 20005-3701 (202) 234-4433
642 1
the arm-waving, the bounding calculations.
2 You buy six months, a year, you can do some O
3 experimento, some analyois, and if you then decido you 4
have enough that can be defended, yr.: ccn then just 5
diopense of the spray.
The point la -- let me say, I 6
think this may be not palatable to your marketing peoole 7
because this was a big selling point, but if you want to l
8 have it by December, I really don't see how you can do it, 9
as much as I would like.
10 If you want to have the system as you want to 11 operate it, you need taore analysis, more data, eix months 12 to a year.
13 CHAIRMAN KRESS:
I think i< hat ne's sayini; is 14 that with the spray, you'd have essentially none et this 15 problem of meeting the design basis accident conditions, l
16 but it would have to be safety grade, and then it would be 17 with a spray and you would have to come back for a 18 licensing change basis later, to get it out.
19 MR. VIJUK:
I understand.
20 CHAIRMAN KRESS:
So I don't know if it is 21 palatable to you or not, but this is --
22 MR, VIJUK:
Spray won't cool, it just delays 23 the transient.
Ultimately, you're still dependent on 24 getting the heat out through the shell.
25 CHAIRMAN KRESS:
If you have a shell with a NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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cooler --
p 2
MR. VIJUK:
Oh, a spray with a cooler.
(
)
3 CHAIRMAN KRESS:
Yes, say, a traditional spray 4
3 MR. VIJUK:
Okay.
Now I understand.
6 See, this is -- if you want to have it approved by 7
December 31 8
MEMBER POWERS:
I would make it clear that 9
that is just a suggestion.
10 CHAIRMAN KRESS:
It's just a suggestion, and 11 you should not consider that as anything the ACRS is --
12 yeah.
And, in fact, you know, that is -- take it just as 13 a suggestion, w/
14 So, with that, I think I will adjourn this 15 meeting at this point.
16 (Whereupon, at 4:19 p.m.,
the Advisory 17 Committee meeting was adjourned.)
18 19 20 21 22 23 24
['}
/
25 s.
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N W.
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CERTIFICATE This is to cortify that the attached procoodings before the United Statos Nuclear Regulatory commission in the matter oft Name of Proceedingt ACRS SUBCOMMITTEE ON THERMAL llYDRAULIC PHENOMENA Docket Number: N/A Place of Procooding: ROCKVILLE, MARYLAND woro hold as heroin appears, and that this is the original transcript thereof for the file of the United States Nuclear
(
Regulatory Commission taken by no and, thoroafter reduced to v-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.
Al W
CDRBETT WINER Official Reporter Neal R. Gross and Co.,
Inc.
i O,f 3 NEAL R. GROSS 1
COURT REPORTERS AND TRANSCRIITERS I
1323 R1IODE ISLAND AVENUE.NW (202)234 4433 WAS!!!NOTON, D C. 2000$
(202) 23444r,