ML20236A274
| ML20236A274 | |
| Person / Time | |
|---|---|
| Issue date: | 03/07/1989 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-T-1719, NUDOCS 8903170022 | |
| Download: ML20236A274 (196) | |
Text
MVQkF%:+
a w.
en agggm%wwn 4/ :, 3$IfllM 1 9.
XH. wM.
y': + xW yt
+3 +
1
~
~
, $v(?,,M
'., -.tik R,) -
- Ygy,
~
p.w qw' '.., o_ [;q,'(% '..
U
.3,
h4 f
7 M3 (f, t ry., e y'\\
- c. n -
c ; (^
i
'2
. d k Y+' b ^ ?. f:
'y l
@g:.Nl.1Q;;[@ V y
i?J
~
1 v
UNITED 1 STATES l T' 1
dhg..Y>
7 NUCLEAR REGULATORY COMM, ISSIONA
.cv x.
4
- 3, v.~
- q. ;9,.
3 --
,y,
, r.
i
%b
' LO 'Tcjg& Q
'l.f ' '
. /;) %
4:"? L '
. i.
2 l',
%, o,W if '
s 1',,'
j{p. ;u ;fe t.
W,: l: 4.,,,.
a,. ',
\\
i t i
+<
y.;... r, - m' e
.u.
13.
.n us g. 4.W;o, --
,,y gj., g[' W i,
,1 e
n.:
.+.
y-,
7 7,
y A.
-================---==---=======--m==========-
i n.T.S 1
'a, W' m,... - :l t 3<
}, "' y f,Qj,, q
},
- C 4
^'"
W3['Y Mf 4, >
...w d UNITEDjSTATE$ NUCLEAIOREGULATORYMOMMISSION fw
\\
4?
- L j
0'
,3,,..
. f, A if p,'
',*(.,'
it Lj.?
4.@
3
- ADVISORY?COMMITTEESONLREACTOR;; SAFEGUARDS"~
M
, :I lf v
3: 1
~' gcc i ; f:, <
7-;r(4]
p s
7
.,.g<
Ao
- p 5' a4
f.7
<2.:
4 T,j. "S:
m' I.. :
,p 1-
)?
'j i
THERMAL HYDRAbLIC: PHENOMENA '
)-
G,W
.!^
L)
'A
,4
' SUBCOMMITTEE 0MEETINGe ic)'
7..
r..
i i
f v,
l
~
. i U;'
r y
I
- l. t M
i
?.
l' g
,' t s
~
S; j ', -i-6
- }.
s i
c:
)
y' g
.s C
j.
i f
' Pages :..1.through 149
,.p b
> ' A$P.
y-h...7
')
~
- - ~ ' '.'
Place:
Bethesda,-Mary p
V<4
'g
)&
- h. _.".,
- b q
Date:
March 7, 1989'"*O Q J 0.0 T. we b-Ae a
eW e
z u
N:
q t
i HERITAGE REPORTING CORPORATION OMReporters l
1220 L Street, N.W., Suke 600 l
4 Washington, D.C. 20005
..C,
?
F' G04 6M i
... _.,._,', w 7 g Q(1].17 th.) u fDh W O'S
]
rg l
. ' ~
T-171' 1
x_-.---___-________
j I
l' PUBLIC NOTICE BY THE
.,i 5 V
2 UNITED STATES NUCLEAR REGULATORY COMMISSION'S 3-ADVISORY COMMITTEE ON REAC'A OR SAFEGUARDS 1
4 THERMAL HYDRAULIC PHENOMENA SUBCOMMITTEE MEETING 5.
March 7, 1989 6
7 8
The contents of this stenographic transcript.~of the 9
proceedings of the. United States Nuclear Regulatory 10.
Commission's Advisory Committee on Reactor' Safeguards (ACRS),
11 as reporten herein,'is an uncorrected record of the discussions 12 recorded at the meeting held on the above date.
13 No member of the ACRS Staff and no participant at 14 this meeting accepts any responsibility for errors or 15 inaccuracies of statements or data contained in this 16 transcript.
17 18 19 20 21 22 i
23 l
24 25 l
l Heritage Reporting Corporation (202)628-4888 O
UNITED STATES NUCLEAR REGULATORY COMMISSION.
(~)
.V ADVISORY COMMITTEE ON REACTOR SAFEGUARDS
(
)
THERMAL HYDRAULIC PHENOMENA
).
SUBCOMMITTEE MEETING
)
).
1 Tuesday March 7, 1989 7920 Norfolk Avenue Bethesda, Maryland The meeting convened, pursuant to notice at 12:30 a.m.
BEFORE:
MR. DAVID A.
WARD Research Manager on Special Assignment E.I. Du pont de Nemours & Company Savannah River Laboratory Aiken, South Carolina ACRS MEMBERS l' RESENT DR. WILLIAM KERR Chairman ACRS Associate Vice President for Research Professor of Nuclear Engineering 1
The Pennsylvania State University II University Park, Pennsylvania MR. CARLYLE MICHELSON Retired Principal. Nuclear Engineer Tennessee Valley Authority Knoxville, Tennessee and Retired Director, Office of Analysis and Evaluation of Operational Data U.S. Nuclear Regulatory Commission Washington, D.C.
DR. CHESTER P.
SIESS Professor Emeritus of Civil Engineering University of Illinois Urbana, Illinois l
Heritage Reporting Corporation
()
(202) 628-4000
l.
L ACRS MEMBERS PPESENT: (Continued)
MR. CHARLES J.
WYLIE Retired Chief Engineer'
(
Electrical Division Duke Power Company Charlotte, North Carolina ACRS COGNIZANT STAFF MEMBER:
PAUL BAEHNERT f-NRC STAFF PRESENTERS MR..BOSNAK MR.'OBRIEN l.
I CONSULTANTS DAVID AYERS ED SIEGAL DAN WILLIAMS GERALD NEILS GERALD NEILS BRIAN MCINTYRE Heritage Reporting Corporation (2.02) 628-4888 O
f.
3 1
PROCEEDINGS x_)
2 MR. WARD:
The meeting will now come to order.
3 This is a meeting of the Advisory Committee on 4
Reactor Safeguards, Subcommittee on Thermal Hydraulic 5
Phenomena.
6 I am David Ward, the Subcommittee Chairman.
7 Other ACRS members in attendance are Mr. Wylie, Mr.
8 Kerr, Mr. Michelson, Mr. Catton, and I expect Mr. Seiss will be 9
here shortly.
10 The purpose of the meeting is to review the NRC 11 staff's proposed policy statement on additional applications of 12 the leak before break technology.
This is SEC-E, the document, 13 draft document, SEC-E-88-325.
14 Paul Baehnert on my right is the cognizant ACR staff
(~3 15 member for the meeting.
V 16 Rules for participation in today's meeting were 17 announced as part of the Notice previously published in the 18 Federal Register on February 21st, 1989.
19 A transcript is being kept and will be made available 20 as stated in that Notice.
l 21 I would like each speaker, first, to identify herself 22 or himself and speak with sufficient clarity and volume so that 23 she or he can be readily heard.
24 The agenda, you have a new agenda in front of you, 25 gentlemen. I do not know if it has any date, but it has us Heritage Reporting Corporation (202) 620-4000 k_)
i L
_________________________o
f I
L K
4 L
L 1
ending at about 5:30. I think we should be able to make that.
'j.
2 There has been some modification in the agenda since 3
the one that was sent out with the earlier meeting notice.
4 I appreciate everyone making it into town in this 5
nasty weather, although I do not know, this weather may be an 6
improvement for Mr. Neils from Minnesota. I do not know.
But 7
we appreciate it.
8 I am not sure everyone is here yet, but if -- we have 9
at least got enough participants to cover us down to about 10 4:00. So, we will go ahead.
11 I would like to emphasize that our purpose today is 12 to review SEC-E-88-325 and just to remind you of what this is, 13 back in, I think it was, about April or early last year, April 14
- 6th,
'88, the staff published a document which was an advanced
(~)
15 notice on rulemaking, I believe, which solicited public ss 16 comments on a proposal to extend what they called the leak 17 before break technology or leak before break argument, 18 extending or it crediting to systems in nuclear power plants 19-other than the systems to which the rule change and the GDC 20 change of 1987 had been made.
21 As you recall, back in 1987, there was a so-called 22 broad scope revision to GDC-4, which permitted the use of leak 23 before break technology to exclude from structural design 24 consideration the dynamic effects of postulated pipe ruptures 25 when certain criteria relative to the pipe materials and IIoritage Reporting Corporation (202) 620-4000
.W I
h6-L 5'
)
J 1
integrity of'the piping were satisfied.
1 2
As a part of the' review of that'issu'e,- it was 3
suggest,ed in several quarters, including in the'ACRS, that' 4
arguments, similarfarguments, or.the same. argument lcould be 5
extended so that the benefits,;if there are any,-of the. leak-6 before break technology could be realized in other plant 7
systems, and, for example,'th'e design or the performance 8
> requirements for emergency core cooling. systems might'be-9 considered.
10' There was also some potential that even the design 11 and,the performance requirements of the containment systems 12 could be affected,.and, finally, there also appeared to.be some 13 potential that equipment qualification issues could be affected 14-by what would amount to a definition of different modified
(}
design bases as a result of using the more realistic arguments 15 16 about pipe failures.
17 Our intent today is primarily to talk about any
~
18 incentives that might accrue from extending leak before break 19 argument. We aren't going to talk very much about the 20 justification for that argument, but we're accepting as a 21 premise that justification might be possible, but it's going to 22 take some dedication of resources to develop the full 23 justification, and what we're trying to establish today is 24 whether there are incentives that are strong enough and 25 interesting enough so that the justification argument should be Heritage Reporting Corporation (202) 620-4000 0
7
.c 1
i1 A
6 e
,o 1
-pursued.
j I
f.
2 In its draft policy paper,88-325, the staff has i
3 concluded.that the justification or the. incentive arguments.are-4 not strong enough to' warrant the significant expenditures.of i
5 staff resources that.it would take to, you know, develop.a j
6 rulemaking or some other method for a regulr%ory process for 7
extending the argument, and, so, what weae doing today is 8
really reviewing that.
9 I personally have looked at the responses they got to l
10 the public notice last spring. I can see where one might come 11 to a somewhat different conclusion than the staff has, and, so, 12 we have asked a number of representatives of licensees and 13 other industry groups to come in and discuss with us-in a 14 little more depth at least. a little further what the incentives 15 might be.
16 After we hear that, I'd like to have an executive 17 session of the committee, the subcommittee, at the end of the 18 day to decide -- review what we've heard, to make some sort of 19 a decision on what we want to take to the full committee, and 20 if there is a message that we think that the full committee 21 should send to the Commissioners on this issue.
22 If you recall, we're on a little bit of an irregular 23 schedule because this policy statement started to move through 24 the Commission before the committee really had a chance or took 25 the opportunity to review it.
i Heritago Reporting Corporation l
(202) 620-4000 0
f
'y, Lij 7
1, We sent a letter to the Commissioners last month
(
2 asking them to hold up their final vote on the topic until we 0
3
.had a chance to. review it in more depth, and, so,-we're doing
~4 that today, and if we decide to, we've got'a couple of hours;
'5
. scheduled for the full committee on, I guess it~is, Friday of 6
this~ week, and with the possible product of that being the 7
letter to the Commissioners later this week.
'8 Let's see. Before going to the staff, a couple of 9
'other items.
10 First, we just received.a letter from an industry 11 group, and I think you've all got a copy of it. It's covered 12 with a note from Paul Baehnert to ACRS members, and it's a
.13 letter of March 3rd addressed to me from the Nuclear Utility 14 Group on Equipment Qualifications.
{}
You might glance at that when you get.a chance. The 15 16 attachment to that letter, which is dated August 5th, 1988, was 17 something you've seen before. It was actually part of -- it was 18 this' group's comment on the staf f's -- to the staff's request 19 for comment last spring, and that is actually attached to the 20 draft copy of SEC-E-88-325 that you have.
But you might want l
L 21 to glance at that.
22 One other point is Item Number 3 on the agenda. I 23 asked the staff at Brookhaven National Lab and Mr. Bill Horak, 24 in particular, to do some calculations for us for our benefit 25 and review those for uc here today, and the calculations were l
Heritage Reporting Corporation (202) 628-4888
[
[
8 f
,1 some perimetria or sensitivity calculations of looking at
'1 l ().
2
'large intermediate breaks in PWR, typical PWR piping systems, l
3 and to see what effect the size of the break and.the speed of 1
1 4
the break, the rate at which.the break opening occurs, to see 4
5 what effect varying those two parameters.would have on.a couple l
6 of other secondary parameters; namely,. peak. clad temperature.
l 1
7 That tells us something about how important the l
8 assumptions about the break in a large' break axis are to the 1
9 effectiveness of the ECCS system, and then also to calculate 10 the rise in containment pressure and temperature following a 1:L break, to see if there is enough that's interestingly different 12 in the rate of rise of temperature and pressure so that there 13 might be some indications of advantage that could be taken in 14 either containment design and performance assessment or in
{}
15 equipment qualification assessment.
16 Mr. Horak will give us a summary of that. We don't 17 you know, I don't think these are absolute definitive 18 calculations, but merely to give us some sort of a ballpark 19 estimate of what we're talking about, if we were to use the 20 leak before break argument to make some modification in really 21 the design basis requirements for certain systems.
22 Okay. Do any other members have anything you' d like 23 to say before we turn to the staff to start out the 24 presentations we've listed on the menu for the afternoon?
25 (No response. )
i Heritage Reporting Corporation (202) 628-4888
. _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ = _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___
l 9
1 MR. WARD:
Okay. Then, Bob Bosnak of the Research
( )-
2 Office staff will begin.
3 MR. BOSHAK:
Well, I'm Bob Bosnak from the Office of 4
Research. We've'had the responsibility for the policy, 5
development of the policy paper.
6 David Ward has already covered many of the 7
preliminary things, but I just wanted to make sure that the 8
members really understand the steps that have taken place.
9 The first thing that we did have was a limited scope 10 amendment to GDC-4, and that went back to '86, and, there, all 11 we're talking about is the PWR main loop, and, again, we are 12 eliminating the dynamic effects, and that's basically all the 13 modification to GDC-4 did.
It permitted one to do away with 14 the pipe whip, pipe whip restraints, and the jet impingement 15 barriers that were necessitated as a result of postulating
(}
16 these pipe breaks.
17 That, of course, aided, the staff believes, in 18 increasing the ability to inspect. We have had several effects 19 that have happened in the past even several months, where these 20 items have interfered with the normal operation of thermal 21 expansion and heat-up and cool-down of piping.
22 So, that is why thic whole thing was started 23 initially, to enhance safety.
24 The broad scope amendment began, as Ward mentioned, 25 and was published in '87, and when the Commission approved Heritage Reporting Corporation (202) 628-4888
1 lg 10
(
1 that, they issued a staff requirements memorandum, and as you
()
2 see, that was dated in '87, approving the broad scope l
3 amendment, and asking us to review whether modifications to the l
4 ECCS and EQ requirements could be accomplished using leak 5
before break technology.
i 6
The Commission was silent with respect to doing L
7 anything as far as containment is concerned.
So, that was our 8
charge, and I do want to point out that they said that any 9
modifications that we do make should be based on enhancing 10 safety.
So, those were our marching orders, if you will.
11 MR. MICHELSON:
Under the limited scope amendment, 12 what was the minimum pipe size that could have an LBB?
13 MR. BOSNAK:
Well, we were talking about the PWR main 14 loop, and that was the only thing that we were talking about in
(}
15 a limited scope.
16 MR. MICHELSON:
You were just -- you weren't even 17 talking about down to six inches or anything like that?
18 MR. BOSNAK:
We weren't talking about anything else.
19 MR. MICHELSON:
Okay, Just the main loop alone?
i 1
20 MR. BOSNAK:
Main loop.
21 MR. MICHELSON:
Thank you.
22 MR. BOSNAK:
As you have heard, the Federal Register 23 notice soliciting public comment was published in April of ' 88, 24 and as far as the policy statement, we developed it based on 25 the comments that we received, and as you see here, we -- well, l
Heritage Reporting Corporation (202) 620-4000 1
J
l>
11 q
1 it's.on the next slideL --' we received a numbe: of comments.
/~~T
- (,)
2 Some were negative, some were positive.
There were twenty-one 3
' comment letters that we received from the utilities, private 4
citizens, various groups and SSS vendors, and, in particular, a L
5 nuclear fuel vendor, and I want to get to that comment because 6
I think it is quite important from what benefits can be 7
achieved.
8 Now, twelve comment letters opposed the expansion of 9
leak before break criteria, and as far as the opposition is 10 concerned, we reviewed those and they were based principally on 11 the fact that we should not extend leak before break into 12 systems that were prone to fatigue cracking, IGSCC, things such 13 as that, and the staff essentially has agreed with that, and in 14 a draft SRP that came out about a year ago, it was a proposed
()
15 revision to SRP-363.
16 We have said that where you hava these kinds of 17 situations, you cannot use leak before break.
So, where you 18 have IGSCC, where you have situations that are prone to erosion 19 corrosion, those kinds of things, leak before break could not 20 be applied.
21 MR. MICHELSON:
Let me ask, Bob, on the broad scope 22 rule, what was the pipe limitation, the pipe size limitation?
23 MR. BOSNAK:
Well, there was no pipe size limitation, 24 but, of course, you have to be able to detect leakage cracks.
25 So, in effect, you might be talking about something Heritage Reporting Corporation (202) G20-4000 l
t I
12 1
that would take you down to about a six to eight inch line in
/"N()
2 order to determine -- to be able to determine reliably leakage I
3 detection, but there was no specific lower limit placed.
4 MR. MICHELSON:
In the broad scope rule, there was a 5
requirement, of course, that you be within the threshold of 6
your detection capability.
7 MR. BOSNAK:
That's correct.
8 MR. MLitlELSON:
That large a leak would be postulated 9
to occur.
10 I thought there was a larger leak, not like a 11 critical crack, but a leakage crack or something that you were 12 postulating in these lines.
Is that the case or not?
13 MR. BOSNAK:
Well, there was a -- you had to be able 14 to determine -- we had a factor. I don't know whether the
{}
15 factor was ten or
-- yeah, a factor of ten.
That you would be 16 able to detect that amount of leakage and not exceed the 1
17 critical crack size.
Perhaps that's what you're thinking 18 about.
I 19 MR. MICHELSON:
What is the critical crack size then?
20 MR. BOSNAK:
Well, the critical crack size depends on 21 the material, depends on the load that's --
l l
22 MR. MICHELSON:
You're talking about 1
23 MR. BOSNAK:
Keith Witham wants to add something to 24 that.
25 MR. WITHAM:
We have a factor of ten on leak
)
i Horitage Reporting Corporation (202) 620-4000
13 1
detection capability, and that takes a lot of things into O(,)
l2 account, but the factors that we have on critical crack size 3.
are a factor of two on length or, depending on how you combine 4
the load, a factor of the square root of two on load.
5 So, I might point.out'that leak detection systems are l
6.
inside containment, and from a practical standpoint, if you're 7
relying on those systems,:maybe the cut-off on size would be 8
perhaps in the six inch range.
9 However, you always have the option of adding more 10 sensitive instrumentation, if you want to, okay, and if you get j
11 sensitive enough instrumentation with our factor of ten, for 12 example, that postulated leakage aize flaw could be quite 13 small.
14 MR. WARD:
Bob, the decision or the recommendation to i
()
15 not credit leak for break argument for piping systems that 16 were, for example, subject to IGSCC, was that based on a 17 perception or understanding that the materials or something in 18 such systems were different in some way, that made the leak 19 before break. argument not credible, or is it simply that you.
20 expected to have more leaks in auch systems?
21 In other words, is it sort of a deterministic reason 22 or a probablistic reason?
23 MR. BOSNAK:
Well, I think it's -- you could probably t
i 24 say it was both, but it's essentially a deterministic reason.
25 In order to apply leak before break, there had to be IIoritage Reporting Corporation (202) 620-4000
I 14
{
1 some evidence, some reliability factor involved that you're not
(
(
2 going -- that you're really going to have leak before break and 3
that you're not going to have a catastrophic failure of the 4
pipe, and in thinning situations, in IGSCC, you don't have that 5
assurance that you're not going to fail in a catastrophic j
6 manner rather than to determine -- to have a leakage amount 7
that can be detected.
8 There isn't the assurance. There isn't the -- from a l
9 probablistic sense, there isn' t the reliability. We' re shooting 10 for something of the order of ten to the minus five minus six j
11 reliability.
12 I think Keith wants to add something to that.
13 MR. WITHAM:
If you have a degradation mechanism, I
14 like fatigue or IGSCC or what have you, it invalidates the
(')
15 before break because leak before break depends on the us 16 postulation of a certain size of leakage, certain size of flaw, i
17 okay, that you have detectible leakage plus our factor of ten 18 that we add for various reasons.
1 19 If you have an on-going degradation mechanism or t
20 piping that may be subject to some degradation mechanism, you 4
21 are no longer assured that that leakage, that that size of that 22 leakage flow will remain the same.
It might get much larger 23 and invalidate the whole leak before break approach.
It might 24 not be stable any more.
25 That's the reason that we do not apply leak before Heritage Reporting Corporation (202) 628-4808
r i
l.
~
'15 1
break to piping systems with fatigue or IGSCC or what have you.
()
2 Should I go over that again?
3 MR. WARD:
Yes.
I guess I don't recall that that 4
argument was quite that airtight.
I 5
MR. WITHAM:
Yes, that is the reason. It' invalidates 6~
the size of the leakage size flaw that you postulate.
The 7
stable flaw. That's right.
8 MR. SEISS:
Fatigue would grow with cycles.
9 MR. WITHAM:
That's right..That -- an actual flaw 10
~could be much larger, for example, than the stable flaw that 11 you' postulate.
12 MR. SEISS:
At some point then, it's why it would 13 leak.
14 MR. WITHAM:
Yes, but that's unpredictable. Okay.
It
[}
15 may or may not leak. It depends on, you know, it depends on a 16 lot of factors.
17 Well,-for example, we have seen fatigue cracks grow 18 essentially around the inner circumference of the pipe and just 19 leak at one point around the circumference, so that you have 20 got essentially a three hundred and sixty degree crack in the 21 pipe that is leaking a small amount.
22 So, it depends on the situation.
23 MR. SEISS:
You say a small amount, you mean a too 24 small amount to be detected?
25 MR. WITHAM:
To be detectible, yes.
j Heritage Reporting Corporation (202) 620-4880 u_____m.____-.____-.__-__..___m_
r 16 1
MR. SEISS:- You observed these?
{
2 MR. WITHAM:
Yes.
3' MR. SEISS:,And.they'have gone to a double --
4 MR. WITHAM:
Yes. Most of these have been due to, at f
5
.least recently, most of these have been due to thermal l
6 stratification, thermal fat'igue.
7 MR. SEISS:
And they have resulted in a double-ended 8
guillotine break?
9 MR. WITHAM:
No.
No.
No.
10 MR. SEISS:
It doesn't~ keep the argument going?
11 MR. WITHAM:
It doesn't have to result in a double-12 ended guillotine break.
I know of no double-ended guillotine 13 break.
I 14 MR. SEISS:
Except the postulated?
15 MR. WITHAM:
E:: cept the postulated one with the.
16 exception of a hundred and eighty degree break, if you will, in 17 the feed water line at the Indian Point Water Hammer, but I 18 know of no others in high energy lines.
19 MR. SEISS:
So, now, I lost the train of your 20 argument about the fatigue crack.
21-MR. WITHAM:
What I'm saying is that if you have on-22 going degradation mechanisms, there's no guarantee that your 23 stable leakage size flaw will remain the same size that you 24 postulate.
Okay. It could be much larger.
Leak a lot less, 25 even, okay.
l Heritage Reporting Corporation (202) 620-4000
1 17
,l 1
MR. SEISS:
Isn't the objective to get a leak before
(^3
( /
2 break?
3 MR. WITHAM:
That's right.
4 MR. SEISS:
You're only addressing one assumed I
5 mechanism.
1 6
MR. WITRAM:
You are applying leak before break to a 7
piping system which is not subject to fatigue or IGSCC.
8 MR. SEISS:
But you haven't explained why a piping i
9 system that is subject to fatigue will not leak before it 10 breaks.
11 MR. WITHAM:
It may, but there's no guarantee that it 12 will.
13 MR. BOSNAK:
It may, and it may have --
14 MR. WITHAM:
It may not.
Okay?
15 MR. BOSNAK:
-- a large dynamic load that could fail
}
16 it. So, again, the probabilities are not what the staff decided 17 that it needed to apply leak before break.
18 MR. SEISS:
In other words, like the Indian Point 19 feed water, you think that was weakened by fatigue to the point j
20 that when the water hammer came, it failed?
21 MR. BOSNAK:
Exactly.
22 MR, SEISS:
Is that true?
I don't remember that 23 there was a pre-existing crack in there.
24 MR. WITHAM:
I think it was a very severe water 25 hammer.
I think that's what happened.
Heritage Reporting Corporation (202) 620-4000
j 18 '
11 MR. BOSNAK:
Whether that increased the' chances.for a I
r"%
()
2' crack or not, I don't know, but the chances are there was some
]
'3 initiator.
I 4
.MR.
WITHAM:
And, for example,.--
5 MR.'SEISS:
. Appreciate it,could have been simple 6
stress, couldn't it?
A 7
MR. WITHAM:
Excuse me?
8 MR. SEISS:
There was some initiator, but the 9
initiator could simply'be an over-stress, can't it?
10 MR. WITHAM:
I think it just ripped off, yeah, 11 catastrophically.
12 MR. SEISS:
How do we get away from that?
13 MR. WITHAM:
Pardon me?
1
~
14 MR. SEISS:
How do we get away from that?
l
()
15 MR. WITHAM:
We do not apply leak'before break to
'16 lines that are subject to severe water hammers.
17 MR. SEISS:
Do you know all the pipes that are 18 subject to severe water hammer?
19 MR. WITHAM:
There has been a lot of operating 20 experience that we can rely on and a lot of studies on that.
I'
[
21 MR. BOSNAK:
The studies that happened with USIA-1, I 22 think, catalogue to a good degree which lines are more i
23 susceptible to water hammer than others, and, again, that's why
)
24 we started when we started with the limited scope rule, we 25 started with a PWR main loop, because it was essentially not l
Heritage Reporting Corporation (202) G20-4000 l
- - - - 9
i 1
19 1
immune, but. essentially it was not subject to these degradation l'
p)-
(_
2 mechanisms.
That's where'we started.
3 Now, if we can move on into --
f 4
MR. MICHELSON:
Let me get a clarification. The case 5
of corrosion erosion, is that a mechanism also which, if'it 6
exists, you can't apply leak before break?
I 7
MR. BOSNAK:
We're saying if'that's prevalent, then 8
you cannot, that's correct.
i 9
MR. MICHELSON:
Now, what do you mean by prevalent?
1 10 MR. BOSNAK:
Well, if you have a situation, in other i
11 words, it occurs in certain materials, certain temperatures, 12 certain oxygen levels, certain pHs, it can occur in the feed 13 water systera, but in a PWR main loop or in some system that has 14 materials that are relatively resistant to erosion corrosion,
()
15 it will not occur or, if it does, it occurs at a much slower 16 rate.
17 John, did you want to add something?
18 MR. O'BRIEN:
My name is John O'Brien of the Research 19 Staff.
20 In response to a question, Dave, about the 21 difficulties with IGSCC, I think the answer partly depends on 22 the geometry of the crack being different because, in IGSCC, 23-you have crack initiation during the life of the plant. These 24 cracks then initiate at the same cross section link-up and tend 25 to get shallower cracks which means that you can lose a greater Heritage Reporting Corporation (202) G20-4080
20 l
1 portion of the cross section of the pipe before it goes
.rh
()
2 through.
3 It's a shallow crack, and then, when you do start i
4 leaking, perhaps a large portion of the cross section is gone, 5
and then you have to demonstrate that what's left is stable 6
under normal plus SSE conditions with the margins that Keith 7
told you about, and we just don't trust UT to tell us that the 8
cracks are that large when you can't see them leaking.
9 We depend on leak detection. I think that's part of 10 the answer.
j 11 MR. WARD:
Okay.
12 MR. MICHELSON:
One other question.
13 MR. WARD:
Well, is this on a different subject?
14 MR. MICHELSON:
Not on --
15 MR. WARD:
We'll let Chet respond to that first.
16 MR. SEISS:
I find it interesting that you' re willing 17 to rely on purely empirical evidence on the issue of which 18 pipes are subjected to water hammer and which pipes are 19 subjected to erosion corrosion, and, yet, nobody seems to think 20 there's enough empirical evidence that there's never been a 21 double-ended guillotine pipe break.
22 MR. O'BRIEN:
When you say empirical, you mean
]
23 historical?
24 MR. SEISS:
Empirical. Based on experience. That's l
25 what arguments I got. That was the statement that was made on Heritage Reporting Corporation (202) G20-4000 0
'21 i
1 water hammer, for example, the same one on erosion corrosion.
~'s
/.(_)-
2 MR.' O'BRIEN:
The NRC has done several studies on the 3
history of water hammer and specific piping. We understand --
i 4'
MR.' WARD:
What Chet is saying is if you did a study 5
like that'on the' history of double-ended guillotine breaks --
6 MR. O'BRIEN:
We have done that, too. We know what 7
the frequency of double-ended guillotine is.
8 MR. SEISS:
I just heard it zero.
9 MR. O'BRIEN:
In Class I.
10 MR. SEISS:
No one has ever seen a double-ended 11 guillotine pipe break.
12 MR. O'BRIEN:
In Class I piping and on nuclear power 13 plants, we get about sixteen double-ended guillotine breaks in 14 the United. States every year, but they're not in nuclear
('T 15 plants.
V 16 FR. SEISS:
We're not regulating anything but nuclear 17 power plants.
18 MR. O'BRIEN:
Right.
But in nuclear power plants, 19 there's never been a double-ended guillotine break in Class I 20 pipe.
21 MR. SEISS:
My observation stands.
22 MR. WARD:
Carl?
23 MR. MICHELSON:
One thing that puzzles me about leak 24 before break is I can understand the philosophy for pipes, but 25 I'm having a little more difficulty understanding what I do if Heritage Reporting Corporation (202) G20-4000 0
l.
i 1
Ec q
P 22 J
L.
.1-I have a bolted closure in that-pipe, 'for instance.- You know, N
2 flange, manh' ole' cover.
3 MR.'BOSNAK:
I'think we're. going to'get to'that.
If i
4.
you postulate that a pipe breaks, what are you going to 5
substitute and,--
6
. MR. SEISS:
I'm not looking for a substitute..I'm 7
just looking for making sure that I look at the whole. pressure 8
boundary and not just one piece of the pressure boundary.
3 9
MR. BOSNAK:
Well, we' re saying the fact that you j
i 10 have~ postulated pipe. breaks are enough to envelope these other i
11 situations, but if you do away with them via leak ~before break 12 or some other means, then what do you substitute?
And that's 13 one of the questions that we have.
14 MR. SEISS:
I don't find that treated in this paper 15 too well, if at all.
You know, the fact that, okay, now we can
[}
16 think about --
17 MR. BOSNAK:
I think in a way it is treated -- if I 18 can, I'd like to move on into the equipment qualification area, 19 because that's one of the areas where this argument does come 20 up, this very argument.
21 If we desire to use some sort of an equipment 22 qualification profile, whatever it be, what do we use as an 1
23 alternative. What do we base it on.
Do we base it on manhole 24 covers of valve bonnet blowing ot_.
Something needs to be 25 substituted for what we have now from the pipe break Heritage Reporting Corporation (202) 628-4880 0
~
23 1
environmental profile.
)
2 And I don't think that.the staff has any argument 3'
with respect to the fact that if you could come up with
-4 something that was less severe, and that's what this first l
less harsh. environmental profiles, if 5
hullet is trying to say, 6
they can be justified, they're going to give you more reliable 7
equipment.
8 The equipment is going to probably last longer.
9 There will probably also be more suppliers. That should help 10 with respect to costs. So, there are a lot of reasons, but,.
11 currently, if you look inside containment first, and then move 12 outside containment, if you look inside containment, you have 13 to be able to apply this to all of the lines that are inside 14 containment.
(
15 Right now, the application of leak before break is 16 somewhat limited, as you have heard. Beside the PWR main loop, i
17 I think the only other line may be perhaps this pressurized or 16.
surge 'ine that has been qualified to leak before break 19 conditions, but unless you can do this for main steam / main feed 20 water inside containment, you're not going to get any 21 advantages.
i 22 So, that, as we see it, is the limitation with 23 respect to inside containment.
24 Now, outside containment, you have less -- well, the 25 space is different, and, again, I think we would be receptive Heritage Reporting Corporation (202) 620-4000
,1
'24 1
-to have work.done by the industry, EPRI and others,_to generate 2
a' replacement profile, if you will, but no work has been dor a.
.3 In the comment letters that came in during the August j
4
' time' frame period of 88, thare was a lot of words, I might
.5' characterize them as, saying that it would be a good idea to do 6
this, and the staff agrees, but it hasn't been done, and we 7
don't have the resources to' undertake a situation in which we.
l
-8 would go out and develop a likely profile.
9 In the letter that you all -- and was referred to by.
10 Dave.when we started the meeting, we did get a letter that came 11 in from the Equipment Qualification Group, and they say, in 12 part, and I just want to dwell on one area that I agree with, 13 essentially, but we'd like to see some work done.
.14 It says, "We further recognize that part of a 15 rulemaking effort in this area will require the development of 16 specific criteria to prescribe breaks in areas where 17 environmental qualification design bases.
We note that in the 18 absence clearly hampers licensees in' utilizing the exemption
)
19 process", and that's one of the things that I want to tell you 20 about, that what we have now,-and this was part of the broad 21 scope rule, we specifically welcomed exemptions to equipment 22 qualification.
23 Since, again, we had no proposed alternative,.we are 24 depending, we were depending, and we are depending on the
'25 industry to come in with a. proposed exemption, and this could Heritago Reporting Corporation (202) 628-4800
25 1
be more easily done for an outside containment area.
If you (m_)
2 have a particular run of pipe in a given compartment and you 3
know what the likely sources of, call them, leakages, whether 4
you have an expansion joint, whether you have several large 5
valve bonnets, whether you have manway covers, bolted closures, 6
anything that would be a likely source of leakage, this is the 7
kind of substitute that we would like to see developed.
8 Obviously, if it were done in a generic way, it would 9
standardize, and that's what we' re trying to do, really, to 10 standardize these kinds of things as far as the indoctry is 11 concerned.
12 If each and every utility comes in with something 13 different, that is not -- well, it uses a lot of resources on 14 the industry's part, on the staff's part. It would be much
(}
15 better if there were a standard profile that could be used, 16 but, currently, it does not exist.
17 MR. WARD:
Okay.
Bob, you think from your 18 standpoint, you think the NRC has in place rules or practices 19 that would -- could accommodate exemptions to the EQ 20 requirements based on this --
21 MR. BOSNAK:
The broad scope rule invited -- because 22 we don't like to regulate by exemption, it invited on a case-23 by-case basis utilities to come in and request exemptions in 24 the equipment qualification area, and that was part of the 25 rule.
Heritage Reporting Corporation (202) 620-4000
ty 17 26 1
MR. MARD:
Okay. But that seems to.be contrary to-i )'
2 what you just said. What'you'd really like to see is something 3
more generic in order to reduce the workload --
4 MR. BOSNAK:
Oh, definitely.
Sometimes --
i 5
MR. WARD:
But you don't like to see generic 6
' exemptions.
7-MR. BOSNAK:
Sometimes the way to develop a generic 8'
profile, if you will, is the
- several exemptions. In other 9
words,. several specific case-by-case things coming in and 10 setting the stage for what'might become more generic. I 11 definitely agree that we all prefer a' generic approach to any 12 of these situations.
13 That's what we have on the next slide. We're saying.
14 that at least in the policy paper, we're saying with respect to 15
'EQ, that --
16' MR. CATTON:
Excuse me. What was the response to the 17
' invitation?
18 MR. BOSNAK:
To which?
19 MR. CATTON:
You said that industry was invited to 20 get exemptions.
What was the response?
Were there many?
21 MR. BOSNAK:
Not invited.
There has been no 22 response. We don't have any -- there's no one that's come in 23 with a specific request for exemption in the equipment 1
24 qualification area using leak before break, and that's what I'm j
25 trying to point out here.
l l
Heritage Reporting Corporation (202) 620-4000
1 3
27
't l'
MR; SEISS:
Excuse.me, Bob. -Againbefore you go,
.O
- 2 ve=
14 ve='s 11*e ee a ve eui#e ee=eric "a t' ere eeeeric 3
'.than a rule change?
4 MR..BOSNAK:
Well,.a rule change would be generic..If 5
we had this profile all developed,.-the research has all beon
'6 done, I think we would be in a. position to say here it is and 7
.we would initiate a rule change, but we don't have the 8
substitute criteria.. All we could say now is come in and 9
develop such a profile, and we already have this in place.
10' Lw, whether we should start 'a separate rulemaking 11 process to say that you can do that when we already have that-12 in-place and nobody has taken advantage of this and has coine in 13 with an exception.
So, as thic first bullet says, we'd like to
'14 gain. experience. We'd like to see some work done,.but up till 15
.the present time, there is nothing.
16 So, that's where we stand with the policy paper, and.
17 we're saying we're not -- we don't want to send a message that
~18 tells the industry don't do anything. We're just saying for the 19 time being, we don't see any advantage of doing anything more 20 than we have now.
When there is a proposed alternative, a 21 generic alternative, then that's the time to go ahead with 22 rulemaking.
23 And the last bullet indicates that the safety 24 benefits are potential, and aa we've been talking about ft here 25 for the past several minutes, the applicability of leak before Heritage Reporting Corporation l-(202) 628-4000 O
L
'r 28 D
1 bree.k'is somewhat limited..It does not apply now across the
"( )
2' board,.and that's the current rule that we have in place.
3 So, it may not be the be all and end all to all
.4-situations and particularly inside. containment. Outside 5
. containment,'there's more hope, I would say, but, here again, 6
we haven't seen any practical approach on the part of the 7
industry to propose something.
8 So, that's where we are with respect to EQ.
9 The next area that I would like to get into is the 10 ECCS.
11 MR. WARD:
One question. You say if there really is 12 going to be anything practical to come out of this for the EQ, 13 it will probably be in systems that are outside containment?
14 MR. BOSNAK:
Again, using leak before break because
(}
15
'the containment atmosphere --
16 MR. WARD:
Just because it's a closed volume?
17 MR. BOSNAK:
I think you're always going to have some 18 line that's subject to postulated pipe break.
You're not going 19 to be able to apply le %) before break to every line inside 20 containment, 21 MR. WARD:
Yeah, and it's a closed volume, where, 22 outside, you might be able to make the argument that --
1 23 MR. BOSNAK:
For particular areas.
l 24 MR. WARD:
Okay.
I understand.
25 MR. POSNAK:
With respect to ECCS, there are several i
Heritage Reporting Corporation (202) 620-4880 I
29 1
1 benefits that the staff determined that the letter writers that I
()
2 sent in comments. They focused on three particular areas.
3 First of all, with respect to diesel generators. If 4
you have a full double-ended break, it requires the fact that 5
you start the diesel generators in very short -- within ten 6
seconds.
This is rather harsh as far as the reliability and 7
maintaining the diesel is concerned.
8 But, separately from leak before break, there was a 9
generic letter that came out awhile ago that reduced the 10 frequency of these severe tests [to one in every six months. So, -
11 this is one particular benefit. hat we think is very positive, i
12 but I think we're getting it from another source, j
J 13 Now, this, I think, o:* all of the things that you've 14 seen, perhaps this is the most important, either EQ or ECCS, 15 and that's the fact that if you can reduce these peak 16 temperatures, you, in effect, will have lower flux leakage, i
17 radio leakage, and, therefore, you should be able to extend the 18 life of the vessel, lessen brittlement.
19 This is very important.
However, this benefit and i
20 the other one that you saw with respect to the emergency diesel 21 can already be achieved via a rule that's on the books. The 22 revised version of 5046 and Appendix K already exists.
It 23 permits you to revise your calculations and do exactly what 24 leak before break would permit.
25 So, we' re saying that these t o important safety Heritage Reporting Corporation (202) G20-4008 O
___J
4 30 l
1 benefits, and they are the most important, I think, of all the
. f'y
~ (,)
2'
. things;that we've seen, can be achieved via the recently-3 revised ECCS rule.
4 MR. WARD:
And these two are the diesel. start' time l
5 and peaking?
Is that what you mean by the two?
6 MR. BOSNAK:
Yes, those two.
l 7
MR. WARD:
Okay.' However, could I just follow-up on 8
that a minute, Chet?
9 However, I see in a recent'-- this is an INSAC
~10 report, which -,let's see. EPRI asked someone to take a.look 11 at alternate AC power at nuclear power plants, and specifically_
12 at the use of gas turbines as for emergencies.
I 13 MR. BOSNAK:
Instead of diesel.
14 MR. WARD: 'Instead of diesels.
And it seems that gas 1( }
15 turbines in their commercial form don't quite meet the starting 16 time requirements even as derived by using the new ECCS rule.
17 I mean, they miss it by -- I forget what the numbers 18 are.
You can get them started in two minutes instead of one 19 minute or something.
20 MR. BOSNAK:
I haven't seen that report, and I don't 21 know --
22-MR. WARD:
I don't know if anybody really wants to j
23 use gas turbines, but it might be a good idea. It might even be 24 a safety enhancement, that perhaps could be realized.
In the 25 flexibility of using another emergency power source perhaps Heritage Reporting Corporation I
1 (202) 620-4880 0
31 1
could be' realized by an extension per the use of this --
()%
(,
2 MR. BOSNAK-Yeah, that sounds like a positive 3
benefit.
4 But,. supposedly -- and, again, whether this new 5
Appendix K best estimate ethodology would permit you to use 6
the gas turbine, I don't know.
7 MR. WARD: 'Well, it doesn't. As I understand it, 8
MR. BOSNAK:
It does not.
9
'MR.
WARD:
-- it doesn't quite get you there.
10 MR. BOSNAK:
Okay. Well, that would be an advantage.
11 MR. WARD:
Chet?
12 4H1. SEISS:
Bob, in the new second sentence under the 13 first bullet, it refers to a "new rule" applying LBB.
How does 14 a new rule differ from the proposed broad based amendment?
I 15 thought that was a new rule.
(
16 MR. WARD:
Well, we would have to take -
process a 17 new rule that says with~ respect to ECCS or if we wanted to 18 include EQ as well, that GDC-4 could be applied in those 19 situations.
20-Right now, it says the dynamic effects are 21 eliminated, and we would have to also --
l l
22 MR. SEISS:
You have to change some other GDC?
23 MR. BOSNAK:
I think we'd have to modify GDC-4 24 further.
l 25 MR. SEISS:
What was this modification supposed to j
f Heritago Reporting Corporation I
(202) 620-4888
()
32 1
do?- I thought that's what the broad based was doing.
\\
()-
2 MR. BOSNAK:
No.
All it did was to eliminate the 3
dynamic effects. The broad. based GDC-4, all it did was to 4
eliminate the dynamic effects, and specifically for EQ and the 5-ECCS --
6 MR. SEISS:
I'm confused between the broad --
7 MR. BOSNAK:
-- those were not --
8 MR. SEISS:
Eliminate the dynamic effects.
9 MR. O'BRIEN:
Chet, the answer is GDC-4 refers 10 specifically to environmental and dynamic effects. That's the 11 title of GDC-4. It speaks nothing about or says nothing about 12 ECCS. ECCS is treated separately in Appendix K and we would 13 have to modify Appendix K, Part 50, of the Code of Federal 14 Regulations.
15 MR. SEISS:
There must be some GDC that addresses 16 ECCS.
1 17 MR. O'BRIEN:
It's funny, but it's stated 18 specifically in Appendix K.
19 MR. BOSNAK:
5046 and Appendix K, I guess, would have 20 to be changed because, there, you talk about pipe breaks all 21 the way up to a full double-ended pipe break.
l 22 MR. SEISS:
I thought GDCs were the very essence and 23 the heart of the matter.
24 MR. BOSNAK:
Well, the lawyers have pointed out 25 several times that we have this dichotomy, that we're still Heritage Reporting Corporation (202) 628-4888
()
\\
33
-1 postulating pipe breaks with respect to ECCS and'the EQ, even "2
though we've'done away with them in a' limited sense'in GDC-4.
3:
So, you,have this dichotomy currently existing.
4 MR. WARD:
I guess it's,not.only the lawyers that 5
.have pointed that out.
6'
'MR.'BOSNAK:
No. The committee has pointed this out 7
as well.
8 What we' re saying here also' is that the existing --
9 with the exception of the gas turbi'ne, the ECCS rule now for 10 doing'away with or treating breaks differently can be applied 11 to all LWRs.
If you wanted to apply leak before break, there 12.
might be some problems, as you've heard, with respect to the 13
'BWRs because of the degradation mechanisms.
14 So, that, again, is another reason why the staff has 15 said that we would prefer if it's at all possible to use the 16 recently-modified ECCS rule and Appendix K.
17
-And the last slide that I have.
If -- again, if.we 18 wanted to use an existing ECCS rule versus the new leak before 19 break rule, again, a replacement for the instantaneous double-20 ended rupture and it's the same argument that you heard before, 21 if we're going to try to apply this to ECCS, we need some 22 alternative.
23 What do we need to have in developing the alternative 24 pipe break?
That's what we're going to have.
25 MR. MICHELSON:
Well, in the past, I think whenever i
f Heritage Reporting Corporation (202) 620-4000 i
l O;
1
1 1
34 1
the questions were asked about what happens if a bellows
(~'
(_j\\
2 ruptures, which doesn't follow these rules very well, what a
3 happens if valve bonnets bolting fails doesn't follow this rule l
l 4
well, the answer always came back, of course, well, the ECCS is 5
already bounded by the double-ended rupture. So, these are all 6
presumably lesser leaks.
1 7
MR. BOSNAK:
That's right.
f 8
MR. MICHELSON:
And that's not too uncomforting, 9
although I think some of the leaks might have been a little 10 bigger, like a manhole on a steam generator, but, at any rate, 11 it was comforting because whether you talked about double-ended 12 rupture, the leakage limit on ECCS, or whether you talked about 13 the manhole cover on a steam generator, it wasn't all that l
14 important, but, now, we're talking about leak before break and
}
getting -- greatly depreciating the amount of ECCS that might 15 16 be needed.
17 But I'm not convinced that all of it has changed, i
18 because as soon as you eliminate the double-ended rupture pipe, 19 we'll have to address these other components, which we haven't l
l 20 addressed in the past. You've never written guidance on how to l
l 21 determine the maximum leakage size from components, just from 22 pipes.
23 MR. BOSNAK:
Well, those are some of the things that 24 the staff faced in trying to say --
25 MR. MICHELSON:
My question really is, and apparently l
l IIeritage Reporting Corporation (202) 628-4000
()
V h
35 1
I'didn't.ask the question right, what -- do you really think
.( )'
2 it's going'to change the ECCS.significantly if we go leak 3
before. break on the pipe and then gc'back and reconsider the 4
other breaks that ans can get, that we used to be' bounded by 5
double-ended and now have to be readdressed?
6 MR. BOSNAK:
Well, unless you go through-and examine 7
each one of these components, it's hard to answer that
.8 specifically. It may not. It-may not afford the' advantage that
- ll 9
.you think you may have, although some of the components may 10
'have.a, call it, limited opening area, and it may, in. fact, 11 help.
l l
12 Unless you look at each and you're going to get into 13 plant specific situations, I would feel, if'you are trying to 14
. envelope and do it generically, you may be back to the H{ J 15-postulated pipe break sizes.
16 MR. MICHELSON:
That's right.
17 MR. WARD:
Well, this apparently must have already l
18 been done to the extent that the staff is comfortable with i
19 accepting the presently-defined double-ended guillotine break j
20 as truly bounding all other possibilities.
21 So, I guess this has been done, this exercise has 22 been gone through --
23 MR. MICHELSON:
Yes.
24 MR. WARD:
-- at some time in some level of detail.
25 MR. MICHELSON:
Yes, it has.
1 Heritago Reporting Corporation (202) 620-4000
s-36 f
1-MR. WARD:
It has.
(
2 MR. MICHELSON:
But, now, if you eliminate the 3
double-ended rupture, now you've got an open exercise again,-
4 and you may find these other ones weren't far from the double-5 ended rupture. In fact, I think a couple of them might have 6
exceeded that.
7-MR. BOSNAK:
Whatever work was done was done a long.
8 time ago, in the early '70s, and much of it is really not 9
documented, and if you start trying to get down and quantify 10 some of these things, you may be surprised.
11 MR. SEISS:
I recall one of the advance reactor 12 plants gets away from some large pipe.
13 MR. WARD:
That's right.
The largest break is in the
'14 ECCS pipe. How about that?
15 MR. SEISS:
To what extent has leak before break been 16 invoked in some of the advanced designs the staff is working 17 on?
1 18 MR. BOSNAK:
Well, I don't think the staff has really 19 seen the level of detail that they need.
You know, to answer 20 that in a general sense, I think everybody wants to use leak 21 before break, but when you start getting down to the specific 22 systems, I don't know where we are.
23 Keith?
24 MR. WITHAM:
Yes. The advanced designs have presented 25 criteria which essentially parrots --
Heritago Reporting Corporation (202) 678-4888 O
+
}
L
.37
-1 MR. SEISS:. ~Which ones, specifically now?-
.2i MR. WITHAM:
'Oh, the EPRI..
3 MR.:SEISS:
4
.MR. WITHAM: -The BWR,'I. guess..I don't'know.
c 5
MR. SEISS:
Well,: that's all right. You told me LWR.
L i6:
MR. WITHAM:. CE, I know, has it,.and the Westinghouse
.7 90.
j A BWR is proposed --
8 MR. MICHELSON:
9 lMR. WITHAM:. However, we cannot pre-approve leak 10 before break.
11 MR.'SEISS:
Don't go away, Bob.
-12' MR. BOSNAK:
.I just wanted'to turn out the 13 projectors.
~14 MR, SEISS:
Can I have you go back to the first 15 slide?
16 MR. WARD:
That's the second one.
17 MR. SEISS:
The one that says chronology.
18 MR.-BOSNAK:
There's the first chronology, 19 MR. SEISS:
The last sentence.
20 MR. BOSNAK:
In the first bullet or --
21 MR. SEISS:
The last sentence on the slide. "The 1
22 Commission has directed that any modifications of requirements 23 should bs based on enhancing safety."
24 MR. BOSNAK:
This came from the staff requirements 25 memorandum.
Heritage Reporting Corporation
(
(202) 620-4000 O
J 38 1
MR. SEISS:
That is' specific to this particular
()
2 action?
3 MR. BOSNAK:
.Yes.
4' MR. SEISS:- That has not been.true for other actions, 5-am I right?
6 MR. BOSNAK:
I would say.you're right, yes.
7 MR. SEISS:
But the idea --
8 MR. BOSNAK:- For this particular action, I -- well, I 9
think because the staff in presenting the broad scope rule 10 said, going forward this way, we were enhancing safety,'and
.11 perhaps they just picked up on that and felt that if you could 12 also enhance safety in these other two areas, then that would 13 be a positive thing.
14 MR. SEISS:
But they, in effect, said that if you --
15 MR. BOSNAK:
I think we have the SRM some place here, 16 if you'd like to --
17 MR. SEISS:
-- are enhancing safety, no relaxation.
18 That's what they said.
19 MR. BOSNAK:
Well, I don't think that means no 20 relaxation because you can have a change in requirements, you 21-can have a relaxation, which can enhance safety.
22 MR. SEISS:
Well, let's say we have a change in 23 requirements that does not change safety at all, but which 24 represents some improvement in reliability and costs --
25 MR. BOSNAK:
I would think those things are positive.
l l
l l
l Heritage Reporting Corporation (202) 628-4088 O
.4 39 l'
MR. SEISS:- But that isn't enhancing safety.
()
.2
'MR.
BOSNAK:. You're talking about something that's l
3
. neutral with respect to safety.-
4 MR. WITHAM:
If you improve reliability,.you're 5
probably enhancing safety.
6 MR. WARD:
Okay. Let's get away from that. Let's say 7
8 MR. SEISS:
Let's say it'does nothing but save the 9
industry and the rate payers money and hassle and leave.out the 10 fact that it might improve safety because they have.got more 11 time to work on something else, but just say it does nothing 12 but save me money.
13 MR. BOSNAK:
I don't think that there would'be a 14
. reason why the staff would turn something like that down.
(V^T 15 MR. SEISS:
With those words right there and similar 16 words in the policy statement that John wrote, 17 MR. BOSNAK:
I think he's quoting directly from the 18 staff requirements.
19 MR.'SEISS:
I know he is. That's why I went back to 20 this and not blaming him.
If the Commission said, unless it 21 enhances safety, forget about it, that's why they said. We can 22 ask them what they meant.
23 MR. O'BRIEN:
The draft notice last April said that 24 safety would he given priority over other considerations, and 25 the public has constantly reminded us in their comments that i
Heritage Reporting Corporation (202) 620-4000
40 1.
the Energy Reorganization Act requires that the staff give
()
2 priority to safety, and the Commission just followed the.
3' congressional mandate. That's it.
4 MR. SEISS:
'So, there's no congressional mandate to l
5 reduce costs ---
l 6'
MR. O'BRIEN:
Right, and we set the priorities.
7 MR. SEISS:
--. even if it' doesn' t change the safety?
8 MR. O'BRIEN:
The actual notices that the priority-9 that the Commission assigns to priority -- right..So, we treat 10 it as a low priority and that's what.you've got. No action at 11 this time..
12 MR. SEISS:
Something that would cost the --
13 MR. WARD:
Okay. Low priority is the equivalent of no 14 action at this time?
15 MR. O'BRIEN:
No.
.{ )
16 MR. SEISS:
Something that would cost the Commission 17 several hundred thousand dollars in staff time or research that 18 would save the industry a hundred million, they can't --
19 MR. O'DRIEN:
No.
20 MR. BOSNAK:
How that would come up on the priority 21 rank, I don't know, but we, the staff, are working on other 22 things --
23 MR. WARD:
Bob, excuse me.
I -
you say you don't 24 know how that would come up on the priorit y rank.
25 MR. BOSNAK:
As far as the Commission is (foncerned, I Heritage Reporting Corporation
)
(202) G20-4000 1
0
41 1
can't say how that would be. You know, how they would look at O.
2 someehine 11ke thee.
3 MR. WARD:
But you'seem, without asking them, you 4
seem to have marching orders from them on this issue not to 5
devote any of your resources ta) that sort of activity.
6 MR. BOSNAK:
Well, we haven't seen anything really 7
identified.
If, in one of the comment letters that came back, i
8 we had'seen something that said this is really going to -- and 9
here is a way we would like to approach the EQ or ECCS and that 10 will save us, you know, millions of dollars and we would like 11 to see the staff, even though from a safety point of view it 12 may be neutral, but we didn't get anything back that way.
13 MR. WARD:
Yeah, but it seems to me that the signal 14 that the Commission or you have sent to the industry is that
{}
.there's no point in spending their resources to develop that 15 16 sort of argument because'you're not going to provide any 17 resources to support it, unless there is something that will 18 enhance safety.
19 MR. BOSNAK:
Well, that's kind of the --
20 MR. WARD:
It looks like we're in a circle here.
21 MR. BOSMAK:
-- message we got from the Commission, 22 that we felt was our marching orders.
We never got into asking 23 the Commission to clarify what they really meant. Did they mean 24 something that was safety neutral.
25 So, whether that message got out to the industry and 1
Heritage Reporting Corporation (202) 620-4000 l
()
l
42 1
whether they reacted.-- would have reacted differently, I
( )'
2' really can't say.
%r 3
MR. WARD:
Okay. Well, we're going to hear from I
4 people from the industry a little later this afternoon. I guess l
5 it would be useful to hear something on that.
l' L
6 MR. BOSNAK:
Right. Exactly.
1 7.
MR. WARD:
Okay. Any other questions for Mr. Bosnak?
8 (No response.)
l 9
MR. WARD:
Okay. Thank you very much, Bob.
10 We are now ready to hear from Bill Horak from 11 Brookhaven.
12 (Pause) 13 MR. WARD:
Okay, Bill, fire away.
You've got an 14 hour1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />.
15 MR. HORAK:
Okay. Thank you very much.
16 Yes, I am going to talk today a little bit about the 17 parametric study that I have done in conjunction with Bob 18 Bennett from the Brookhaven National Laboratory.
Bob is our 19 main computer analyst there and turns out that apparently the d
20 data that was generated in this study turned out to be one of 21 the main problems that we had.
22 It started about a month ago when we were contacted 23 by David Ward to look at a very specific thing, and that was to 24 determine the effects of the break opening time on various 25 sizes of breaks on the peak load temperatures on the Heritage Reporting Corporation (202) 628-4000 0
i 43 1
containment pressure and temperature for intermediate and live
. ()
2 breaks.
We excluded small breaks from this particular study.
3 Since, we were pressed for time to do this we were-4 forced take, essentially off the shelf, the deck and computer 5
codes'to do this.
At this particular time, we did have 6
available to us at Brookhaven laboratories a version of relap 7
5 mod 2 code.
8 The particular version that we had -- our machine up 9
and running was cycle 36.
Which we had obtained from the joint 10 research center at -.
We used this version because we have an 11 IBM machine now at Brookhaven and this was the version that had 12 been modified for IBM.
13 To run on this particular code, we used a standard 14 problem deck which was for a four loop PWI deck. To get a 15 containment descriptic.n we adapted a deck from a millstone
(}
16 plant that was used for the contain -- 4 mod 6 deck.
17 We intially decided to look at four different break 18 sizes, going down to approximately small break sizes. That was 19 2 times 100% break, 2 times 50% break, 2 times 20% break and 2 20 times 10% break.
We varied the break times from what we called 21 instantaneous, and by that we meant we used a particular valve 22 model that tripped open within the minimum -. We then, 31so, 23 looked at various opening times ranging from, essentially, 0.1 24 seconda to nearly a full minute.
25 This is a reconstruction schematic of the primary Heritago Reporting Corporation (202) 628-4000
44
-j 1
1-
' system'which was in the sample problem for.PWR for a loop l
2' plant. In this particular plant, the three loops that were
'3 impacted did not have breaks in them, were lunped together here 4
with-the connection to the pressure riser. There was a U2 model 5
of the steam generator and single pump model.
6 Again, the safety injection was fully modeled, but 7
was all modeled as coming into the same junction in the' cold-8 lakes.
I have not mapped out here the secondary side of the 9
steam generator. That consisted mostly of auxiliary feed water 10 and main feed water B modeled as boundary conditions through a 11 series of inlet pipes, steam space and then, finally, a series 12 of valves representing the rest of the plant.
13 On the break side of the plant, this represented a 14 single loop, and we made just three modifications to this. The 15 original deck was modeled with only a single valve representing 16 the breaks. In other words, just a one-sided break.
We 17 introduced an interface valve in the interface area and added 18 an additional valve so that we could model double-ended breaks 19 as we needed.
20 We also modified the containment structure slightly l
21 to reflect the content work.
22 The vessel -- internal to the vessel was a faj.rly 1
l 23 simple model.
It did consist of just a single pin with six i
'24 axial levels in the cere region. The lower plenum and the upper l
25 plenums were both splitted to sort of like a mixing region and i
l 1
1 Heritage Reporting Corporation (202.) 67.0-4880
I 45
.1, then.a stagnant region top and bottom. There was a core top t
..()-
2 area, an' inlet annalist with the down comer. bypass'.
3
- The loops connected in through here and through this n
)
4 region here.
The containment description we took from a
]
o 5
Milstone. deck for contempt.'We happened to have this'one J
l 6
available to us at the time.
7 The total volume.of this particular one was 2.25, 8
2.25 million cubic feet. The flow area was set at 11,000 cubic 9
feet. Within the containment area, we placed --
10 MR. WARD:
How do you -- I'm not picturing the flow 11 area.
What does that mean?
12 HR. HORAK:
Okay. Well, the way I modeled this 13 containment was sort of like a right circular cylinder.
14 MR. WARD:
Oh, okay.
15 MR. HORAK:
And the 11,000 cubic feet would be
(}
16 essentially what I considered to be like the inner diameter of 17 this right circular cylinder with restrictions for equipment.
18 MR. WARD:
Okay. So, the flow is coming in one end j
19 and --
20 MR. HORAK:
Right.
21 MR. WARD:
-- it's compressing as it moves toward the 22 other end?
23 MR. HORAK:
That's correct.
24 MR. WARD:
Okay. I understand.
2.5 MR. HORAK:
Okay. We celected seven lump structures Heritage Reporting Corporation (202) G20-4000 O
l
M
.-t 46 1
'to put in here.
Basically,.they consisted of stainless steel
(
2
. lined concrete which we separated from carbon steel lined L
3 concrete'because of.the difference in the thermal ~ properties.
4
'Just regular old concrete, stainless'ateel and carbon steel.
5
.These three structures were double sided. This'one 6
and this.one were single sided. In other words, we assumed that 7
these were exposed on both sides. This one was also single 8
sided embedded carbon steel lined concrete, and then,. finally, 9
the main portion of the building was modeled'as a carbon steel 10 lined' concrete cylinder which was exposed to ambient 11 temperature at the outside.
i 12 This is a sampling of the run matrix that we did.
13 The first simulations that we did were what we call the. base 14 cases and'this involved instantaneous breaks. In other words,
/"T 15 breaks that opened up the appropriate sizes within the minimum V
16 time set.
17 MR. MICHELSON:
When you talk about sizes of a 18 hundred and eighty, whatever, --
19 MR. HORAK:
Yes, sir.
20 MR. MICHELSON:
-- that is a hundred percent of what?
21 MR. HORAK:
A hundred percent of the inner diameter r
22 of the main circulation pipes.
23 1R. MICHELSON:
And what was the one that you chose?
24 MR. HORAK:
We selected the cold lake and it had a 25 cross sectional area of roughly four square feet.
Horitage Reporting Corporation (202) G20-4000 o
__._..___.._.__m_._______m_____
l; 3
y 47 I
1 MR. MICHELSON:
And what size pipe was that, roughly?
.7 s
(_)
2 MR. HORAK:
Roughly, it's a twenty-seven inch inner 3
diameter pipe.
4 MR. MICHELSON:
So, you picked a particular plant to 5
do this on?
l 6
MR. HORAK:
We picked the plant that was l-7 representative in this sample problem which came with the code.
8 MR. MICHELSON:
Okay. Thank you.
9 MR. HORAK:
I have listed here the simulation times 10 that we simulated for, and also the amount of the CPU time.
11 I've listed the CPU time to give you a handle of how long each 12 one of these were taking.
13 In the base cases, the two times one hundred percent l
14 case --
(~/
T 15 MR. WARD:
That's related to the bill you're going to s.
16 send us.
17 MR. HORAK:
No. The real reason is because as the 18 blow down is much, much more quicker, you have much more 19 crossings of saturation lines and the steam tables had to be 20 consulted more often. That's what eats up the time.
21 And in addition to the bill, which you are going to 22 get, let me assure you, the idea was to show that when we got 23 down to the two times ten parcent case, we were going through 24 these very, very quickly in terms of the CPU tin.e 25 The two times -- in the base cases, the two times the Heritago Reporting Corporation (202) 620-4000
48 l'
hundred percent' cases, the two times fifty percent case, did ir()
2
.not run out as fully as we would have liked it to go..The two 1
3 times hundred percent case started developing water packing 4
problems. However, owe had already attained the first peak of
'5 the peak clad-temperatures, and peaks in the containment.
6 atmosphere.
7 MR. MICHELSON:
When you talk about two times ten 8
- percent, 9
MR. HORAK:
Yes, sir.
10 MR. MICHELSON:
-- ten percent aga!n is the cross 11 sectional area of that particular pipe?
12 MR. HORAK:
Yes, sir.
13 MR. MICHELSON:
What. kind of break configuration are 14 you using for calculating: discharge?
15 MR. HORAK:
Okay.
If I can go back,.--
16 MR. MICHELSON:
Well, can't you just tell me?
17 MR. HORAK:
Oh, yes, sir.
What it was is I --
18.
MR. MICHELSON:
Do you have a whole equivalent area 19 of two times ten percent?
20 MR. HORAK:
Yes, sir.
Yes, sir. Located at the i
21 bottom of the cold lakes.
22 MR. MICHELSON:
Okay. Thank you.
l 23 MR. HORAK:
Okay. So, we did not take those any l-l 24 further at that point in time.
l 25 The first one where we assumed that there was a non-Heritage Reporting Corporation (202) 670-4800
.( )
1 lL
J 1
49 l
l' instantaneous break was pretty much to just give us a handle on r^s -
f
(_)
2 the base' case, and we assumed a break opening time of 0.'1 3
seconds.
4-There was not -- in terms of the running times, as 5
you can see here, there was not much difference in the total 6
running times that we' simulated these for.
However, we did 7
eliminate from these parametric cases the two times ten percent 8
case.
This was done because when we looked at the two times 9
ten percent base case and ran a few parametrics, it became 10 clear we were going to have to run it out to much, much more l
.i 11 than a hundred seconds of simulation time to really see any 12 peaks in the containment atmosphere.
13 MR. SEISS:
What's the double asterisk mean there?
14 MR. HORAK:
Oh, I'm sorry, sir. That means the run
(}
15 was terminated by a failure of the code, in this case, water 16 packing.
17 MR. SEISS:
What do you mean, the code?
18 MR. CATTON:
Don't we have all sorts of protection 19 built in to handle that?
20 MR. HORAK:
I did not write that five code. What it 21 did was it informed me et an error that it did generate water i
22 packing and that it was chutting itself off. T did not know if I
23 that qualifies as protection or not.
Jo, but that is what the 24 code itself generated failure.
U 25 MR. CATTON:
I hope the rest of your results are not j
l l
Heritage Reporting Corporation i
(202) 620-4888 l
(2)
1 50 1
too dependent on the code.
l e~()
2 MR. HORAK:
No, sir, i
3 MR. CATTON:
Good.
Well, they're a little bit 4
dependent on it.
5 MR. HORAK:
In this case here, we now started to 6
extend the break times out by orders of magnitude. First, 7
extending it to a break time of one second, and then out to ten 8
seconds. Again, 9
MR. CATTON:
Why did it run for two times a hundred?
10 MR. HORAK:
What, sir?
11 MR. CATTON; Why did it run for two times one hundred 12 and not for two times fifty?
13 MR. HORAK:
In this case here, the failure, as I was 14 about to say, is not truly a failure, but I've marked it as 15 such. In this case here, the system pressures started to 16 approach the pressures within the containment, and we 17 terminated it, and in this case here, the last one we did was a 18 break time of fifty seconds.
19 I'm going to briefly go through --
20 MR. MICHELSON:
Could you tell me what you mean by 21 break time?
22 HR. HORAX:
Yes, sir.
As I stated earlier, we 23 modeled these breaks as opening and c]osing valver 24 MR. MICHELSON:
Yeah.
25 MR. HORAK:
-- and I varied the valve speed so that l
l 1
Heritage Reporting Corporation (202) 620-4000 O
E ---
l 51 1
.it would go from a fully opened size to the specified size that o
. /~Y l
(_j
-2 I wanted to.-
1
-3 MR. MICHELSON:
So, you took the cross sectional area l
4 and you expanded it'over time'to spread over, say,. fifty 5
linearly.--
6 1G1. HORAK:
It was a linear experience, yes, sir.
7 MR. MICHELSON:
-- of the area of the break?
8 MR. HORAK:
That's correct.
9 km. MICHELSON:
Okay. Thank you.
10 MR.-HORAK:'
I am going to briefly.go over these 11 curves here, but I_have a summary slide that I want to discuss 12 more later' These are just to show various trends as a 13 function of the opening time for various sizes. This is the 14 containment pressure here and for the smaller opening times,
(
there is.not much difference in any of the curves.
15 16 When we open it up at fifty seconds, the rate of 17 increase in the containment pressure does vary on this one.
18 The containment atmospheric temperature follows the same 19 trends, with the smaller opening sizes not varying -- small 20 opening times not varying very much here, and the longest j
21 opening time does have a different rate of increase of rise in 22 the atmosphere temperature.
23 A nhort presentation on the pre-clad temperatures 24 here.
We only followed these out to the first peak because of i
25 the time limita.
The time of the peaks of the shortest ones, l
1 l
Heritage Reporting Corporation (202) G20-4080 0
J
d L
52
'I again, is. essentially.the same. As we started to open the
(
2
' break, we did get decreases in peak, and when we used the 3
largest opening time of fifty seconds, we really did not see
'4 much variation'over this time frame of the peak clad h
5.
temperature from the. steady state values.
6.
Again, I'm not going to go through this too much.
7 This is for the fifty percent case. It also follows essentially 8
the same trend with only the longest time opening having a l
9 significant:effect on the rate of increase of the pressure.
10 This trend is, of course, also reflected in the rate 11 of increase for the atmosphere temperature in this one here.
12 For the peak clad temperatures, and I'll discuss this a little 13 bit more when we get the chart up, in this case, there's a 14 little bit more spread in the break as a function of the break
'15:
opening time than we got for the hundred percent case.
16 With the one second.one actually having slightly 17 higher peak clad temperatures than the 0.1 second break, and 18 the two slowest ones, the ten and the fifty second ones, not 19 showing much difference from the steady state values.
20 Finally, I'm going to go over just briefly the twenty 21 percent case. These are run for much longer periods of time, a 22 hundred seconds, roughly double that. When we terminated this 23 particular one at sixty seconds, the containment pressure had 24 not yet reached its peak. We terminated it mostly for data 25 handling purposes. We were generating lots of points for these Heritage Reporting Corporation (202) 620-4000
I c
l 53 1
1 1
graphs and we.were having trouble getting more than this on
-( N gj 2
here.
3 The containment atmospheric temperatures which did 4
lead for this particular case did peak out and change slightly j..
5 the steady state value even for the fifty second case, and, 6
again, over this time frame, there's not much variation in peak 7
clad temperatures in the steady state values.
8 MR. MICHELSON:
Is.there.some simple explanation on l
9 why the peak clad temperature for the two times fifty case was 10 higher than for the two times a hundred percent?
11 MR. HORAK:
I really do not know why that is the 12 case. I have looked slightly at the output, but I do not have 13 an explanation at this time for that, a simple one, at least.
14 MR. MICHELSON:
And the wave form -- that might be
{}
15 more expected, but I didn't understand the peak clad 16 temperature.
17 MR. HORAK:
In fact, if we could go to the table 18 here, for the base case on this --
19 MR. CATTON:.You didn't put asterisks on this one.
20 MR. HORAK:
I'm sorry.
I guess I could plead in 21 this case here. The other one was generated by the computer 22 analyst. The secretary had to type this one.
So, she's going 23 crazy enough as it was.
24 As has been pointed out significantly for the base 25 case, the peak clad temperatures, the two times fifty percent Heritage Reporting Corporation (202) 620-4008
i 54 1
case, is roughly eighty degrees higher than two times a hundred lh 2
percent case, and also significantly here, the timing is on the 3
order of 7.
seconds.
4 We looked at this particular case with many different 5
time steps and we have always generated essentially the same 6
results. I found it very -- my own personal opinion is we 7
needed to look at it a little bit more in terms of possibly 8
spacial nodalization.
9 I would have expected the peak for two times a 10 hundred percent case to be again around 1600, two times the 11 fifty percent break, but also equally significant, I would have 12 expected it to be about four seconds sooner in time, in about 13 the three second time range.
14 Within a group of break sizes, with the exception of ggg 15 this first one here, the instantaneous case, in general, the 16 larger the break size, the larger the peak clad temperature.
17 Okay.
With increasing time --
18 MR. CATTON:
Are all these peaks and the first peak 19 blow down peaks?
20 MR. HORAK:
Yes, sir, they are.
We did not --
21 MR. CATTON:
So, you really don't know what the peak 22 is?
23 MR. HORAK:
We did not track out to the second peak.
24 That is correct.
25 MR. CATTON:
You didn't go to the second peak and you Heritage Reporting Corporation (202) G20-4000
-o
+
<II p
1 1
s 1
55 1-can't tell if a small break is frequentlysin'peakiin the'second
/~T
. (,j 2
-break rather than the ---the reflect peak.for --
t 3-
' MR '. HORAK:" The reflect. peak for small' break could,-
4 indeed, befhigher.
]
5 MR '. CATTON-Or equal?
I 6-
' MR. HORAK:
Or equal.
That's. correct.
7 Again, for the break openi'ng times, these do not seem 8
.to be significantly affected, 'even for the T equals fifty
~
9 second cases -- I'm sorry -- the T equals ten second cases in 1
10 terms ofitime.1They.are. lengthening somewhat in terms'of the; j
L 11 time for the' peak clad. temperatures.
j 12 In' terms of the peak containment pressures,.value--
13 wise, there does not ceem to be any' difference in the-value of 14 the peak containment pressure as a. function of. break opening 15 time, over the times that we have modeled, l
(}
16 The time of the peak does vary with the break opening 17 time by a few seconds and by the time you're out to a break
.i 18 opening time of T equals fifty seconds, it's significantly I
'l 19 increased.
However, within a particular break opening size, j
i 20 there is not much difference between the values.
l i
21 Also, between the two times hundred percent size and
-l 22 the two times fifty percent size, there's not much difference 23 in the peak values.
]
1 24 In this case here, we also -- not surprising, the_two j
25 times twenty percent case always has the peaks at the latest
]
l 1.
1 Heritage Roporting Corporation
]
(202) 620-4800 l
\\
i
56
\\
1 point.in time, andlthe two times fifty percent peaks are always i( ) '
2 later than the two times hundred percent peaks in terms of 3
time.
4 The peak containment temperatures within themselves 5
are a little bit earlier than the peak containment pressures.
l 6
With'the exception of the largest break, they're within a few 7
seconds, and in terms of the largest break time, they' re about 8
twenty seconds earlier.
9 However, again, the peak containment temperatures, as 11 0 you might expect, with regards to the peak containment 11 pressures do not vary significantly over the size of the break 12 opening time nor over the size of the breaks.
It affects --
l 13 the only energy sync that you have is the' containment walls and 14 certain response time is much, much greater than the response
}
time of dumping the fluid out into the. system.. That does not 15 16 overly surprise me.
17 I'll just go to my summary. slide here. We did do a 18 series of pipe break transients, and what we were interested in 19 here was. comparing amongst trends amongst the various results.
20 The only thing that -- one of the most significant things that 21 we discovered, of course, wac that for the same break full I
22 area, the peak values of the containment temperature and 23 pressure did not vary significantly with break opening time.
24 Additionally, there is not much difference between 25 the two times hundred percent size and the two times fifty Heritage Reporting Corporation (202) 620-4000 0
57 l
1 1
percent size in terms of the value of the containment l
()'
2 temperature an'd pressure. Twenty percent size does obtain 3
containment. pressures and temperatures.that are about six psia i
4
, lower and about twenty degrees Fahrenheit lower in, terms of 5
temperature.
6-That's it.for now.
l 7
MR. WARD:
Okay. Thank you, Bill.
I~ guess there are J
l 8
ru) real surprises there.
l 9-Let's see. The first case, sort of an anomaly on the
~
10 fifty p'ercent whole gives you a higher temperature than a:
11
.hundred percent whole.
Doesn't the -- that's really.notLon the 12 first time that's been observed in these sorts of calculations, 13 I don't think.
14 In fact, doesn't Appendix K really say that there has 15 to.be a calculation over a range of openings and --
16 MR. HORAK:
Yes. Normally, what you would do here is 17' you'd have to vary what's called'the discharge coefficient --
18 MR. WARD:
Yes.
19 MR. HORAK:
-- which affects the critical flow model 20 and, normally, that's not one. Normally,.that value varies from 21 around 0.6 to 0.8.
l 22' MR. WARD:
Okay. So, that really -- this really isn't 23 anomalous or at least it isn't any more anomalous than what we
{
L 24 observed before.
1 25 MR. HORAK:
That's right.
Heritage Reporting Corporation (202) 628-4888 l
L
h
(
4 58.
I 1-MR. ~ CATTON:
Degrees of this kind of a calculation is b-2'
'an absolute.'Never mind.
3 MR. WARD:
Yeah.
I know. Eighty degrees. Eighty 4
degrees, yes.
5 MR. CATTON:
Eighty degrees. Eighty degrees.
Those 6
. temperatures are the same.
7 MR. MICHELSON:- How.about'the trend in the 8
calculation, like peak clad temperature?
As time moves slower, 9
breaks have a higher peak clad temperature.
10 MR. CATTON:.The small break can have a higher peak 11 12 MR. MICHELSON:
No, no.
This is the big break. Two
- 13 times one hundred.
14 MR. CATTON:
All the correlations that are built into
[
15' the transfer package and that code can well be a glitch that 16 will.give you fifty, sixty, eighty degrees one way or the 17 other.
So, it just doesn't mean anything.
Most temperatures, 18 as far as operations are concerned, are the same.
And that 19 third one, which is the two times twenty percent, unless you 20 carry it to the second or third peak, doesn't mean anything 21 either.
22 MR. MICHELSON:
But I was curious about the time 23 effects. Why does the one second seem to be trending higher?
24 Now, maybe it's a glitch in the model, all right, but the 25 model's consistent at least.
Heritago Reporting Corporation (202) 620-4000
59 1
MR. CATTON:
What are you saying?
j cm
'\\_)
2 MR. MICHELSON:
It is consistent.
From instantaneous 3
to one second, the peak clad temperature for a hundred percent ~
4 break was consistently increasing.
5 MR. CATTON:
Where are you looking at?
6 MR. MICHELSON:
I'm looking at the peak clad 7
temperature for instantaneous, 1511, one tenth second, 1538, 8
one second, 1545.
9 MR. CATTON:
It really should have gone the other j
10 way.
11 MR. MICHELSON:
I thought so.
12 MR. BOSNAK:
You delay the time to --
13 MR. MICHELSON:
But this one doesn't.
14 MR. WARD:
So much for --
(~)
15 MR. CATTON:
Those are just filled with all kinds of
'm d l
16 little logics --
17 MR. MICHELSON:
There are big differences. I was just 18 kind of -- I thought the trend, though, would be the other 19 direction.
It's consistent.
20 MR. CATTON:
Well, because you delay the time to 21 drying out the tubes and the pressure is falling, the more you 22 delay that time, the more you lower the load application 23 because you take more energy out when it's still saturated.
24 MR. WARD:
Okay. Well, fine points that probably 25 aren't particularly important right here.
i Heritage Reporting Corporation (202) 620-4000
60 i
.1 Anything/else?
t 2
(No response.),
W 3
MR. MARD:
Bill, thank you very much. : Appreciate the -
L 4
effort and the report.
5 Let's take a break now until' twenty-five/after.
1 6
(Break.)
7 MR. WARD:
Our next-speaker is going to be Mr. Ayers 8
for Combustion Engineering.
'9 MR. AYERS:
My name is David Ayers. I'm from 10 Combustion Engineering.
I will.be the first of several brief 11 speakers today to talk about extending applicability of leak 12 before break.
13 My role today is to. restate something.I said many 14 times over the past couple of decades, and that is that we 15 believe in leak before break.
We have been involved or
(
16 advocates of leak before break for a long time. We put together 17 the justification for leak before break for our Palo Verde 18 plants before the rules were established and helped to 19 influence those rules.
That leak before break is for main loop 20 piping, was approved by the NRC, and is now used in our current 21 generation of System 80 plants.
22 Other operating plants with NSSS as designed by 23 Combustion Engineering have submitted a topical report to the 24 NRC for review for elimination of pipe breaks in main loop 25 piping and that review is in progress.
i l
Heritage Reporting Corporation (202) 620-4000
l l
61 1
MR. WARD:
Dave, when you say it was used with Palo r^s I
()
2 Verde and others, you mean used to justify not providing the 3
pipe whip supports and so forth?
4 MR. AYERS:
That's right. Only the dynamic effects 5
which are now defined in the GDC-4.
l 6
MR. WARD:
Okay.
l 7
MR. AYERS:
The reason why we're confident in the 8
reality of leak before break is because we've done modest 9
studies. We've done more than would be normally required 10 because, again, we were advocates of leak before break, but we 11 had to know that when we demonstrate leak before break, that 12 it's really true.
13 We've looked at cases where we have very large cracks 14 in pipes and main loop pipes, and we said, okay, we can
}
tolerate a crack halfway around circumference and still remain 15 16 stable. We've looked at dynamic effects in pipes, and it's not 17 just applying dynamic loads to a pipe with a crack in it, but 18 we built models of piping systems like this and we put a crack 19 in some region of the pipe to determine the impact of the crack 20 on the dynamic loads.
l 21 Does the crack make things get worse or does it make 22 things get better?
Certainly, we've demonstrated in several 23 published papers that in the main loop piping, a crack in the 24 pipe make the dynamic loads in the region of the crack go down, 25 meaning that it tends to be stable. It doesn't tend to be a Heritage Reporting Corporation (202) 620-4000 GkJ
. _ _ _ _ _ _ = _ _ _ - _ _ _
62
\\
1 collapsing kind of mechanism there.
.()
2 We also have looked in detail to the material 3
properties needed for this kind of analysis, and we review --
4 well, we take as much data as we can, combustion data, industry 5
data. We typically, when we do an analysis, we find all the 6
data we can. This is a J-integral, which is the ductile crack 7
extension parameter, and we find all the data we can and we use 8
some curve like this in our analysis, the lower bounds of 9
everything. Again, it gives us the maximum amount of confidence 10 in our prediction of leak before break.
11 Some concern also about what parameters to use, what I
12 is the definition of this integral thing. We've been involved 13 in that and done detailed studies to convince ourselves that 14 there are several people out there saying, well, JM is right,
{}
15 JG is right. We' re absolutely convinced that if you do an
)
16 analysis the way we do, the proper parameters to compare with 17 is JD. That turns out to be the most conservative. We think not 18 only is it the most conservative, it's right.
19 But these are things where we've looktd in depth j
20 again to maintain as much confidence as possible that leak 21 before break is real.
(
22 We have compared our detailed analysis methods to
)
23 simplified methods that have been developed br Electric Power i
l 24 Research Institute and other folke, and that gives us support 25 that the simplified methods in the regions and geometries and i
Heritage Reporting Corporation (202) 620-4000
()
I 1
63 1
materials where they are applicable are conservative analyses
()'
2 and also benchmarks our detailed methods that allows us to 3
extend the analysis methodology to regions beyond where the
(.
4 simplified methodology applies.
5 We have also continued our-leak'before break studies 6'
beyond the main loop piping. We've looked at some smaller lines j
7 for the advanced light water reactors and we have demonstrated l
8 leak before break down to lines of about ten inches in diameter 9
without compromising the one GPM assured leakage with the L
10 safety factor of ten.
11 MR. MICHELSON:
Have you looked at components other l
12 than pipes?
13 MR. AYERS:
No, we have not.
We have looked at main 14 loop piping for all plants. We have looked at the particular 15 ALWR line, the direct injection line. We have looked at surge
{}
16 line for our current generation of plants.
The On Wang plants 17 in Korea. We have demonstrated leak before break for main loop 18 piping. That's easy.
19 We've demonstrated that the surge line, we can 20 satisfy leak before break criteria even when we use the 21 stratified flow as the design criterion.
Now, this is more I
22 difficult because the line was designed for stratified flow, 23 therefore, it's much more flexible than the present generation 24 of operating plants surge line. So, it presents an even greater 25 challenge for leak before break, but we still demonstrate that l
Heritage Reporting Corporation (202) G20-4000
64 1
.that.is satisfied again with the one GPM leakage rate for the
- h)
A 2_
safety factor of. ten.
3 MR. WARD:
You say the line was designed for 4
stratified flow?
5 MR. AYERS:
Yes, we have --
6 MR. WARD:
Why is it more flexible?
7 MR. AYERS:
Because with the stratified flow, you 8
permit it to bend.
9 MR. WARD:
Okay.
10 MR. AYERS:
The surge lines previously were 11 reasonably short and they had a few bends for the thermal 12 expansion, but the stratified flow condition which put hot 13 water on the top, cold water on the bottom, causes the pipe to I
14 bend, and any restriction to the bend causes high stresses.
15 So, this line is very flexible and is allowed to bend
(}
16 and, therefore, --
17 MR. WARD:
But why does that present more of a 18 challenge to the leak before break argument?
19 MR. AYERS:
Well, the leak before break, for example, 20 when I showed a picture of a main loop and I said main loop is 21 a very stiff line, you can cut a crack all the way through i
i 22 there, and the load just goes away.
It's very stiff.
23 MR. WARD:
Okay.
24 MR. AYERS:
A more flexible line is harder to 25 demonstrate leak before break because you can get large loads.
Heritage Reporting Corporation (202) 628-4080
l 65 1
The load can't shed to somewhere else. The load stays there and t'y L( j 2
tends to tear the pipe open.
3.
MR. WARD:
Okay.
1 4
MR. AYERS:
We recently have had discussions with the 5
NRC about performing leak before break.on the main steam line, l
6 and the NRC has agreed that that seems like a reasonable thing 7
to do. We have not progressed very far in this analysis, but it L
8 is a job that will be being performed in the near future.
9 MR. MICHELSON:
In looking at the main steam line, 10 are you looking at the possibility of a steam generator 11 overfill and how it might affect the system?
12 MR. AYERS:
We would look at all transients in the 13 steam line.
14 MR. MICHELSON:
That will be one of the transients
(}.15 you will look at?
16 MR. AYERS:
Yes.
17 MR. MICHELSON:
Thank you.
18 MR. AYERS:
All the work that we've done to date with 19.
leak before break was oriented toward defining a criteria, 20 loading criteria, applicable to pipe whip, prevention of pipe 21 whip restraints, jet impingement, blow down loads and some sub-22 compartment pressurization.
23 These are all the dynamic effects that are currently 24 mentioned in the GDC-4, and for these blow down loads, although 25 the leak before break eliminates the necessity to consider blow Heritage Reporting Corporation (202) 628-4888
't
66 1
,down. loads due to a large break, double-ended. guillotine break,
(),2 it still tells you that you have to. consider them the next 3
line, and we do consider the next smallest. break in the 4
computation of blow down loads and sub-compartment 5
pressurization.
6
.This is the end of my brief summary-on current l
7 applications and things that we've done in the past.
1 8
I would like to introduce Mr. Ed Siegal, also from l
9 Combustion, who will proceed to discuss future applications of
.10 leak before break.
11 MR. SIEGAL:
As Dave caid, my name is Ed Siegal. I'm 12 also from Combustion Engineering, and we sort of structured 13 this presentation to show, first of all, why we have a lot of 14 confidence in the whole theory and methodology of leak before
( }
15 break, and that's one of the reasons why we feel comfortable 16
. recommending that the application of leak before break be
'17 extended.
11 8 The thing that we would view for near term future 19 applications of leak before break that we feel would have i
20 beneficial effects on the industry really fall into three major 21 categories.
22 One would involve the subjects we talked about this 23 morning, the environmental qualification of equipment, 24 containment pressure and temperature profiles, and the 25 emergency core cooling system requirements, and we think all of IIeritage Reporting Corporation (202) G20-4000
L 67 1
1 the relatively near-term benefits that we can visualize fall
(
2
.into one of those three categories.
3 101. MICHELSON:
Are you going to talk about the 4
containment pressure any further?
5 MR. SIEGAL:
The next. speaker, Dan Williams from 6
Arkansas Power and Light, will be discussing that a little bit.
7 MR. MICHELSON:
When he does, I'd'like to have him 8'
comment on the presentation of BNL because they don't' agree 9
with that' kind of a conclusion, and what kind of calculation 10 did they do.
I'd like to hear about it because --
11 MR. SIEGAL:
Okay.
I see Dan is shaking is head yes' l
12 back there.
13 MR. MICHELSON:
Okay. Thank you.
14 MR. SIEGAL:
This is actually -- I'm only here for l
)
15 presenting two slides and introducing Dan. This is actually the I
16-second slide and my last one.
i 17 In order to take advantage of any of these future 18 benefits, we think the process is fairly clear just to get 19 started, and the process is really to decide what breaks can be I
20 eliminated by leak before break technology and then what are
\\
\\
21 the remaining breaks that one still should assume the double-22 ended guillotine for, and, so, the process then would be to 23 determine which of the largest breaks that could not be 24 eliminatri 'y lcak before break.
25 As Dave Ayers mentioned a minute ago, we have begun Heritago Reporting Corporation (202) 620-4888
()
f 68 1
the path of looking at the main steam line leak before break
'( )
2 within' containment.
Our study right now would be limited to
'3 inside containment, main steam line, and from this process of 4
then finding the next limiting break, of course, we would want 5
to develop the new peak pressures, mass energy releases, 6
temperature time curves and these are all within containment,
.7 to find new conditions within containment that affect all of I
8' these items, and, finally, determine new ECCS requirements l
9 based on those studies.
10 MR. MICHELSON:
When you do this, are you going to 11 look for breaks other than in pipes?
Are you just going to go 12 by the old traditional rule because the old rules kind of 13 bounded these other breaks, but now you have to go back and 14 rethink other break possibilities, such as manhole covers,
[}
15 valve bonnets and so forth?
16 MR. SIEGAL:
There was a comment made this morning by i
17 the NRC, I believe, that one of the letters they received said 18 that it would help to have established new criteria if we're 19 going to go forward with the process, and I would certainly 20 concur with that comment, that the next break size, I think, is 21 not necessarily a pipe, but it would require a system review, 22 and in our case, since we are focusing on inside containment, 23 it would be a system review focused inside containment.
24 MR. MICHELSON:
But you are recognizing that maybe 25 there are other leaks that didn't count before because they Heritage Reporting Corporation (202) 620-4000
69:
I were' bounded may now be-the consideration and they may not be h
2
'in. pipes?
0' 3
MR. SIEGAL:
That's correct. One of the issues raised b
4 this morning was manways and we are aware.in the industry that 5-there has-been some bolt erosion or corrosion problems:and.we 6
agree that --
7' MR. MICHELSON:
Foactor coolant pumps have even had a r
8 little bolting problem on occasion.
i
'9 MR. SIEGAL:
That's correct.
10 MR. MICHELSON:
Quite a bit of bolting problems.
11 MR. SIEGAL:
And, so, finding the next largest break 12 size or the controlling break size, I think, is part of the 13 process that industry has to go through to get to that next 14 step,'and we have not done that yet, but we recognize that
{}
15 would be the next step.
16.
Dan Williams from Arkansas Power and Light is going-17 to talk now about the benefits in a much more detailed format 18 of why we would like the right to go ahead and do some 19 engineering studies vis-a-vis preliminary, of course, and I 20 think he's going to address the containment issue that you just 21 mentioned.
22 MR. MARD:
Ed, maybe Dan can handle this question, 23 but let me ask you first.
24 This is sort of a technical process, but what about L
25 the regulatory process?
Do you see a path for doing this?
Heritage Reporting Corporation (202) 628-4888 l
l
70 1
What do you need from the NRC in order to take, you know, begin llh 2
to take action on that sort'of whole process?
Is there a new 3
rule?
I mean, are there things already in place that you can 4
use?
5 MR. SIEGAL:
Well, I can answer that easily.
I don't 6
know. I'm a structural analyst. I'm not a licensing engineer. I 7
would let our licensing people talk and decide what they think 8
in the way of new regulations would be required.
9 When we did begin our effort on the main steam line 10 within containment, we were faced very quickly through informal 11 talks with NRC with questions as to why we feel that was a 12 proper candidate, and we did, in fact, perform a study, the 13 initial report to the NRC, juctifying why main steam line 14 within containment was a proper candidate, and, to my 15 knowledge, they have informally concurred with us now, and, so, g
16 that was a pretty clear communication path, I think, on tre 17 technical level.
1C As far as the licensing aspects goes, I leave that to 19 others.
20 MR. WARD:
Okay. Thank you.
21 MR. WILLIAMS:
I'm Dan Williams, Arkansas Power and 22 Light.
23 I would like to comment briefly on the last question 24 in this way.
If I can drop back just a minute to the comment 25 that was made this morning with Mr. Bosnak that a lot of the Heritage Reporting Corporation (202) 620-4000 0
71 1
safety benefits.that have been raised with respect to this
()
2 issue are potential. They are not. actual. They are not known.
-3 And, in fact, the things that I'm going to be talking-about, I 4
don't know if we can do them or not. I don't know what the end 5
results.are going to be. I don't have a lot to base the t
6 conjecture that I'm going to provide to you on because we 7
haven't been down those roads.
8 We have not done those analyses. We have not pursued l
l 9
them. We have not applied the resources necessary to answer 10 those questions.
11 As long as the staff is patently unwilling to putsue 12 that path, our resources won't be applied to answering those 13 questions, to developing those answers.
That's one thing 14 that's got to happen.
The door has got to be left open for us
)
to pursue it.
There's got to be some hope of success, in other 15 16 words.
17 Whether that's a new rule or whether that's a promise 18 of a new rule should we be able to substantiate its need and 19 its applicability, I'm not sure.
20 One other thing that may have to happen is also the
.21 elimination of the dis-incentive that's been recently provided 22 for the industry to take initiative on safety issues or at 23 least with respect to working with the NRC and that's the l
24 review fee schedule that --
l 25 MR. WARD:
That's the what?
IIoritage Reporting Corporation (202) 620-4000 0
72
-1 MR. WILLIAMS:
The review fee schedule that's
(
2 currently in place.
3 If we've got to' provide a million dollars to review
]
4 any submittals we make for pursuing this, that would also be a 5
dis-incentive to pursuing these questions further.
6 So, I think.that's two main --
7 MR. WARD:
If you supply two million, you' d probably 8
get twice as many comments.
9 MR. WILLIAMS:
Right, right.
So, what we need to be 10 able to pursue this is some hope for success and some hope for 11 some cooperation and' team work with the staff in pursuing l
12 these, what we consider to be, potential safety improvements.
13 There is --
14 MR. WARD:
You know, we heard from Bob earlier that
}
the staff doesn't want to devote any resources to this sort of 15 16 thing because the industry hasn't shown any interest. So, I 17 guess we're in a circle.
18 MR. WILLIAMS:
I think that's correct, and what I-19-would hope that this meeting and maybe some other things we'd 20 be able to do would be to shed some light on what promise there 21 is out there on why those doors should be kept open.
=
22 There are -- the current regulatory process has a 23 great emphasis on incremental safety improvements at this time, 24 and I expect that there will be a lot of these incremental 25 safety improvements pursued, that is to say, follow-up to the Heritage Reporting Corporation (202) 620-4000 0
')
l e
En 73 1
l
'l IPE letter.
+
()
2'
'I think some of the things we' re going to talk about
~
3 here have.as much potential'for' improving safety as some of the 4-things I.would-anticipate as going to get' pursued as a: follow -
5 up to1the.IPE letter, and I would hope that they.could receive 6'
the same amount of enthusiasm from the staff as those things 7
would.
l 8
.MR.
MICHELSON:
I would think that one of the early-j l
9 on things you would want to address before you got too' deeply j
10 involved in all this was to decide how much smaller a' break.
11 size you could even justify.
If it isn't much~ smaller, then 12 forget it, and, so, the first question is what is the 13 alternative break going to be, and that's when you have to 14-start.looking at all the other things we talked about today.
(}
15 MR. WILLIAMS:
That's absolutely correct. It's got to 1
16 be taken on a step-by-step basis.
17 MR. MICHELSON:
And are you taking that step among l-L 18 your first?
J 19 MR. WILLIAMS:
I think so, and I think Mr. Siegal 20 indicated that --
21 MR. MICHELSON:
I wasn't sure that'was a high l
l 22 priority item that you do before you pursue too far down the 1
i.
23 line the details of all this.
24 MR. WILLIAMS:
Yeah.
You've got to define what the 25 next limiting break is once you apply leak before break, Heritage Reporting Corporation (202) 628-4888
'(,
74 1
certainly, f
'2 Now, I'm? going to talk.in four basic areas. The four'
[
,3 you see'up here now.
l f
~4 one-has.to do with containment-building integrity.
5 One with environmental qualification of equipment.
One'with 6'
emergency operating procedures, and/one with plant equipment-7' and its relationship to operational flexibility, e't c.
8 MR. MICHELSON:
Now, is your discussion'inside 9
containment or outside as well?
10 MR. WILLIAMS:
Our focus is inside containment.
q 11 MR. MICHELSON:
Thank you.
12 MR. WILLIAMS:
I certainly wouldn't want to foreclose 13 other considerations outside containment.
14 MR. MICHELSON:
Just so I understand the focus of
.f V('i 15 your presentation.
16 MR. WILLIAMS:
Right. In terms of containment-17 building integrity,.the potential benefits here are that we l
18 could reduce an overly-conservative containment temperature l
19 pressure profile.
I haven't done calculations to'see how much 20 or how conservative those profiles are. I don't know if the 21 leak before break will lower the' size break to twenty percent 22 of the reactor coolant system piping cross section or ten 23 percent or five percent or forty percent, and I don't know what i
24 that will do to the pressure, except what I saw presented 25 awt'.le ago as well as you did.
1 Heritago Reporting Corporation (202) 628-4888
_V Jd -
,,'(
e 1
75 c
l' But if it lowers even as much as what I saw awhile 1
2-ago, it will' permit us to reduce the cumulative fatigue on j
3 portions of the containment' building. structure by lowering >our 4
.4
. test pressures, which we routinely do, integrated leak tests 5-under Appendix J 100,-Part 50, that we apply to that, and the 6
bottom line'on this, whether we were'able to lower it:by ten 7
pounds or. twenty, is that we will enhance the actual'
'8 containment integrity.
SF Now, we're not saying we're damaging it unacceptably 10 now. We're.just talking about an incremental improvement over 11 what we're doing now, and this also will reduce our costs and I
12 the time it takes to pump up to the pressures and increase the 13 fatigue life on the structure.
14.
MR. MICHELSON:
Is fatigue life a limiting
)
. 15-characteristic right now?
?
16 MR. WILLIAMS:
No, it's not, and as I said, 17 MR. MICHELSON:
So, what difference does it make if l
18 you do reduce it?
It's not any -- it's not beginning to limit 19 you yet.
Not for the foreseeable --
20 MR. WILLIAMS:
Yeah. As I said, the current situation 21' is an acceptable one, but we're talking about improvements over i
22 what's acceptable.
As many things as we pursue today in the 1
23 area of safety improvements, incremental safety improvements, 24 improving what is acceptable, to something that is better.
25 The next area is environmental qualification of Heritage Roporting Corporation (202) 620-4808
~O f
/-
R 76
' 1' equ'ipment. One of'the things that it's'my understanding we run.
(
)
2 into'in environmental qualification of equipment is that we 3'
begin~to limit.ourselves to some, in a few cases, more exotic-4 pieces of equipment th'at.can meetuEQ requirements, whereas, 5
more standard, possibly even more proven and reliable, 6
equipment thatEdoesn't.specifically meet EQ requirements is 7
eliminated.
F 8
MR. CATTON:
Is your equipment that sensitive that 9
ten or fifteen degrees and ten pai can make a difference?
10 MR. WILLIAMS:
If that's all we' re talking about, I 11 don't know.
12 MR. CATTON:
That's what it looked like from those 13 earlier slides.
11 4 MR. WILLIAMS:
Okay. Let me comment on that. It's not 15 just the peak temperature and pressure that we're dealing with.
16 It's also the time to reach that. Now, a lot of the equipment 17 performs its actuation functions in short period of time, such 18 that if you simply lengthen out the time to the peak 19 temperature and pressure, the errors that will see at the time i
20 of actuation are much lower, and I'll show you another case in 21 a few minutes with regard to an application on a sub-cooling 22 margin error where we convinced ourselves that we could apply i
23 small break loca instead of large break loca where we reduced 24 instrument errors from approximately fifty degrees sub-cooling 25 margin to approximately thirty.
Heritage Reporting Corporation (202) G20-4000 0
77 1
'MR.LMICHELSON:
On the. question of wipe, you're.
e
)
2 saying that ' thirty seconds makes a big difference, : that some
' 3.
equipment will fail. shortly thereafter?'
4 MR. WILLIAMS:
-No,.no.
It's --
L 5
MR. MICHELSON:
Forty or fiftyfseconds?.
6.
MR. WILLIAMS:
No. Its' function is accomplished 7
before.
L 8
MR. MICHELSON:
I realize that,.'but if you do reduce-1 h
9
'the pressure and temperature, you're somehow saying -- what' 10
. difference does that make in terms of the qualifications?
11 MR. WILLIAMS:
It means it does not have to pass a 12-qualification test at the higher temperature and pressure 13
'before I can use more standard equipment.
'14 MR. MICHELSON:
From the cale,lation, it didn't look 15 like it would make any difference, ut'ess we're talking about a 16 much, much, much smaller break.
17 MR. SEISS:
I think what he said is that if the piece 18 of equipment is through with its job in ten seconds, for the 19 lower break sizes, the temperatures and pressures at ten 20 seconds, so, it's much, much less than they are.
21 MR. MICHELSON:
I didn't think we're ever going to 22 get break sizes of ten percent of what we're now dealing with 23 24 MR. SEISS:
No.
25 MR. MICHELSON:
-- for the entire containment, j
l Heritage Reporting Corporation (202) 620-4000 l
()
I i
78 1
MR. CATTON:
You know, if you start trying to take n)
(
2 advantage of that sort of thing, you're going to have to go 3
back and write the kind of computer code that can give you 4
time, humidity, variations as a function of spacial location 5
within a volume.
Hey, they don't exist yet.
6 MR. MICHELSON:
We never challenged those short-terms 7
on the --
8 MR. CATTON:
The codes you use are lump parameters.
9 I've been a little bit concerned about the qualification as it 10 is, but if you start trying to back off and reducing the 11 temperature, you're going to have to look where the break is 12 relative to your piece of equipment, and you may well be 13 subject to a lot more stringent qualification requirements.
14 MR. WILLIAMS:
That's a possibility.
15 MR. CATTON:
Probably ought to be anyway.
16 MR. WILLIAMS:
On the other hand, you may be able to 17 restrict it to that loop and have -- if you're talking about 18 things like that, to have the opposite loop with an even lower 19 error.
20 MR. CATTON:
You probably could already do that 21 without changing anything.
22 MR. WILLIAMS:
For a large break loca?
23 MR. CATTON:
Sure.
24 MR. WARD:
Not quite as easy.
25 MR. CATTON:
If these things are some distance apart.
Ileritage Reporting Corporation (202) 620-4080
i.
l L,
79 i
1 MR. WILLIAMS:
The point here is that -- and, again,
(
2 not saying that we.can't, but this is a possibility, something 3
.yet to be pursued, if we can lower the EQ requirements, we 4
would be able to use more standard equipment, lead to more 1
5 standardized maintenance requirements.
Using calculations, we 6
can increase the lifetime replacement of some equipment, which l
7 will lengthen the replacement intervals.
8 If we have more reliable equipment due to the use of 9
more standard equipment, we can lengthen the maintenance times 10 on them. We can simplify our spare part planning effort by use 11 of more standard equipment and increase the part l
12 interchangeability.
We can increase the operating margin for 13 how close we operate to actuation set points that are based on 14 overly-conservative large break loca conditions.
[ }
15 We can reduce overly-conservative instrumentation 16 errors, and this leads to other things I'll talk about in a 17 minute with respect to EOPs. The bottom line on all this is not l
18 just so that we can reduce our costs, but we can also reduce 19 systems down time which reduces the man rem exposure and leads 20 also to enhanced safety.
21 MR. MICHELSON:
I'm talking about public health.
22 MR. WILLIAMS:
All right. If we had more reliable 23 standard equipment in there and --
24 MR. MICHELSON:
It's more reliable because there is a 1
25 bigger choice of vendors?
Is that how you're getting it?
1 l
Heritage Reporting Corporation (202) 628-4888
80 1
MR. WILLIAMS:
That, and it's more standard proven-
)
2 type equipment, less-exotic, and if.we have to replace it less=
3 often, you introduce the possibility for installation errors 4
less often. These all lead to enhanced safety.
5 In the area of emergency operating procedures, I 6
talked awhile ago about reducing instrumentation uncertainties, 7
and this does certain things for us in the areas of emergency i
8 operating procedures.
9 Pressurizer pressure, actually pressurizer levels 10 should be up here, too. Both have'large errors associated with 11 them that are applied as a result of conditions attributed to 12 large break loca.
13 MR. CATTON:
Is that because of the time response of 14 your instrumentation is poor?
15 MR. WILLIAMS:
The time response?
/}
16 MR. CATTON:
Yeah.
17 MR. WILLIAMS:
No.
It's because of the high pressure
'18 and temperature that's calculated to occur and --
19 MR. CATTON:
But the pressurizer pressure, for l
20 example, it's going to do nothing but reduce following the 21 break.
22 MR. WILLIAMS:
That's correct.
23 MR. CATTON:
So, the only thing that could be wrong l
24 with it is it wouldn't track well.
25 MR. WILLIAMS:
That's correct.
t l'
Heritage Reporting Corporation (202) 620-4000
f f\\.
L 4
81-
~1 MR.. CATTON:' Steam generator levels are the same kind 2:
of. thing.
3 MR. WILLIAMS:. Or a.large break.loca. The problem is 4
that.forla lot of= plants,.at.least, they apply the.large break
'S loca errors for use of pressurizer pressure doing anything.
6 MR. CATTON: _ Margin to saturation. That's'just 7-temperature measurement,_ pressure measurement and a 8
calculation.
9 MR. WILLIAMS:
Yeah. That's one of the most 10, interesting and useful ones.
11 151.. CATTON:
Your temperature'and pressure are at a 12 maximum when you start. So, where's the problem?
13 MR. WILLIAMS:
Well, the problem is -- and let me'get 14
.to that in,just a second.
15 MR. CATTON:
Fine.
16 MR. WILLIAMS:
But we're dealing with things like 17 seventeen percent errors here and twenty-eight percent errors 18 here attributable to the environmental conditions created by
-19 large break locas.
20 MR. CATTON:
Somehow, I'm lost. Is it the transducer 21 or is the wires and stuff that are outside of the primary j
22 system that are exposed to something?
23 MR. MICHELSON:
What's causing the error?
24 MR. CATTON:
Where is the problem?
25 MR. WILLIAMS:
It's the environmental condition on Heritage Reporting Corporation (202) 620-4000
- O
82 1
the transducer itself.
()
2 MR. CATTON:
The environmental condition on those 3
three transducers are in vessel or in the steam generator.
4 MR. WILLIAMS:
Not in the steam generator.
5 MR. CATTON:
Isn't the steam generator level with a 6
transducer inside?
7 MR. WILLIAMS:
Okay. The transmitter rather than the 8
transducer.
9 MR. CATTON:
Transmitter.
Okay.
10 MR. WILLIAMS:
I'm sorry, I'm not an instrument man.
11 MR. CATTON:
I'm not either.
12 MR. WILLIAMS:
Well, you know more about it than I do 13 apparently.
14 MR. MICHELSON:
I'm not either, and I'm puzzled 15 because I don't understand.
If, indeed, the hypothetical
)
16 accident occurs, you might experience these larger errors 17 because of the --
18 MR. WILLIAMS:
That's correct.
19 MR. MICHELSON:
-- more severe environment, but if, j
20 indeed, the real accident is much less, and I don't have to go 21 through ar.y leak before break theory to produce that, the real 22 accident is less, then the errors are less and what's your 23 argument?
24 MR. WILLIAMS:
The argument is precisely that. The 25 argument is --
Heritage Reporting Corporation (202) 620-4000 O
m muumi
i i 83 1
MR.'kICHELSON:
Less errors --
h'2 MR.. WILLIAMS: ' --:that'I don't know what size my-3 break is. My operator doesn't know what size lmy break is.
4 MR. MICHELSON:
I think you've got the. instruments ~to.
'5 tell;you the: size of.the break.anyway.
6 MR. WILLIAMS:
That's precisely --
7 MR. WARD:. No, no no.
Explain how this' allowance e
8 for. error isLa penalty in your operation. That's what we need 9
to hear.
10~
MR. WILLIAMS:
Right.
Yeah, and I'm going'to use 11 margin to saturation as a specific example of that, but you 12
' don't know.
You do not have an instrument'to tell you what 13 siz'e break you've got. You've got to assume the worst case and l'
14' plow that into how you write your emergency. operating
/~T 15 procedures, and as I said, we're talking about errors up to
.V 16 twenty-eight percent for a wide range steam generator level at 17 our plant. I don't know about other plants.
18 Margin to saturation is a particularly good example.
l 19 We used to require a fifty degree tack-on to the margin to i
12 0 saturation and that's either done in your procedure or tacked 21 directly on to your instrumentation, usually in the procedure.
l 22 The reason for that was with the large break loca 23 environmental conditions. That'a what you calculated as the 1
1 L
'24 error at a thousand pounds process pressure, actually right at 25 fifty pounds temperature error, and a margin to saturation.
i Heritage Reporting Corporation (202) 620-4000 a
l:
84 1'
l 1
MR.LMICHELSON:
You're adding fifty degrees on to
()
2' whatever the required' margin is?
3.
MR. WILLIAMS:
The required margin is actually zero 4
for the application of emergency operating procedures, but we 5
maintain a fifty' degree margin to accommodate instrument' 6
errors.
7 Now, we thought about the application on this 8
particular case at our plant, this parameter, in our EOPs. We 9
reviewed it, determined that the only time that that parameter 10 is of importance is for small break loca, not large break loca.
11 Now, this hasn't been done at all plants, and in that
.12 case, changing those conditions dropped our instruments to at 13 least thirty degrees, and we're applying a thirty degree margin 14 of saturation requirement now instead of a fifty degree one.
~
15 Now, what this does, dealing with things like steam 16 generator tube rupture, one of the things I try to do as an 17 operator is drop the primary pressure as fast as I can to 18 equalize the secondary pressure to minimize the tube leak, but 19 I can only do that so far because I bump up against this margin 20 cf saturation requirement, a fifty degree margin of saturation 21 requirement.
22 By dropping it to thirty degrees, now I'm reducing my 23 tube leak and reducing my offsite releases.
24 MR. MICHELSON:
Well, you certainly can drop it to 25 thirty even now, I would think, because the --
Heritage Reporting Corporation (202) 620-4088 O
L
\\*
85 1~
MR. WILLIAMS:. I have.
(b7 2
MR. MICHELSON:
Yeah, because that --
3 MR. WILLIAMS:
Right.
[
4 MR. MICHELSON:
What you're postulating isn't 5
.affecting. containment significantly anyway.
6 MR. WILLIAMS:
Right, and I have done that.
Not all 7
plants have done that. A lot of plants --
8 MR. MICHELSON:
I'm just trying to track your 9
argument here on why --
10 MR. WILLIAMS:
I understand. My argument is this an 11 example of the types of things that can happen when you drop 12 out the large break loca requirement and drop back to the small 13 break loca. Not all plants have done the type of thing that we 14 have done at our plant with the margin of saturation.
15 MR. CATTON:
I guess I'm lost. I thought you said 16 that the reason that you could reduce instrumentation 17 uncertainties was because the containment environment bothered I
18 the transmitters. I thought transmitters if they got wet or 19 something failed.
I didn't know that they would slowly produce 20-more error as the temperature and pressure went up.
Somehow 21 I'm confused.
22 MR. MICHELSON:
They can.
23 MR. CATTON:
Those things you can calibrate.
- 24 MR. WILLIAMS
The calculations on error directly 25 take into account the environmental conditions, the temperature Heritage Reporting Corporation (202) 620-4000 0
86 1l and the pressure that it's seeing, and the difference is
)
2 significant in the error that's calculated.
I 3
MR. MICHELSON:-
Level is a good example of where the I
l 4
environment does affect it because now you're using a reference 5
leg of water and you start heating that reference leg by the 6
environmental condition and that can start to shift the 7
instrument around, too. The other, I think, is difficult.to 8
see.
9 MR. WILLIAMS:
Now, if I could move on, perhaps I'm 10 able to eliminate safety injection tank isolation. Now, again, 11
-- or safety injection tanks.
I don't know if I can do that or 12 not.
It's got to be pursued.
l 13 But let's say that I can, now, currently, in the 14 steam generator tube rupture procedure, greater than charging 15 pump capacity, one of the things I've got to do is I'm lowering 16 primary pressure. When I get down close to safety injection 17 tank pressure, I've got to go isolate that thing to keep from 18 getting a plateau, slowing down my depressurization and 19 increasing my offsite releases.
l 20 If I eliminate the safety injection tank, I don't 21 have to do that any more. At our plant, to do that, and I 22 suspect at some others, because of the severe restrictions on 23 the ability to isolate those tanks because of the possibility 24 of large break locas, I have to actually go down to the local 25 motor control center, open the cabinet, and hold in the Heritage Reporting Corporation (202) G20-4000 O
87 f
1 contactor to get that valve to closed because of all the inter-()
2 locks and controls that are on the valve power and controls.
t 3
That's with an operator that has to leave the control 4
room and go do that during a time when lots of other things are 5
going on, a very confusing, stressful situation. It adds to 6
that.
7 I get to focus on more realistic event conditions as 8
well.
Right now, the emergency operating procedures'are 9
complex enough. We have done a good job of improving them over 10 the past few years, but they're chill pretty involved, and they 11 will always be because we've got a fairly involved animal out 12 there that they're dealing with.
13 But they're more involved than they need to be 14 because they've got to envelope large break locas. They can't 15 concentrate on more realistic event conditions in those. The
('))
16 bottom line is there's ways that this will reduce offsite l
17 releases, especially with respect to steam generator tube 18 ruptures.
l 19 We can minimize the operator confusion during 20 situations that are already stressful enough. We can minimize 21 personnel hazards and man rem exposures and things like going i
22 down to the local NCC to close the SIT isolation valves. We can 1
23 simplify our emergency operating procedures. I have talked to 24 our operators extensively over the past several years and 25 worked a lot with them in developing EOPs, and one of the l
Heritage Reporting Corporation l
(202) 620-4000 1
f^%
l
88
'i strong impressions that I've gotten is that they're just --
()
2 they L,ake.some of these EOPs a little -- with a grain of salt 3
because they know that they're written to protect against 4
incredible events that will never happen and they sure would 5
have a lot more confidence in them if they had a feeling that 6
those EOPs were directed at something that was real.
7 And you put all these together and,.again, I think we 8
can say these are directed at enhancing safety.
9 MR. MICHELSON:
Are your procedures symptom based?
10 MR. WILLIAMS:
They certainly are. The first ones 11 ever put into effect.
12 MR. MICHELSON:
So, what does the reality argument 13 have to do with it?
14 MR. WILLIAMS:
The reality argument is-that even with 15 the symptom, they've got to protect against large break locas.
{}
16 MR. MICHELSON:
If they. indicate a large break loca, 17 yes, then they have to take appropriate actions for large break 18 loca.
19 MR. WILLIAMS:
Symptoms don't indicate events. That's 20 the whole point.
21 MR. MICHELSON:
No, no.
You're right. You respond to l
22 the symptoms, I thought, not to the event.
l l
23 MR. WILLIAMS:
That's correct. But your response to 24 those symptoms has to be --
25 MR. MICHELSON:
If the cymptoms are those of a large Heritage Reporting Corporation
]
(202) 620-4000 j
(2)
i 89 1
break, whatever that might be, then'you respond accordingly by f( f 2.
your procedures.
3 MR. WILLIAMS:
You don't have symptoms that 4
correspond to -- that indicate a certain event has happened 5-with the exception of steam generator tube rupture, at least 6
not in our procedure. MR. MICHELSON:
I was trying to determine the reason.
8 vhy you argue that because you've got big breaks, you're 9
somehow complicating your symptom-based response.
10 MR. WILLIAMS:
I'm saying that our responses to 11' symptoms.have to accommodate large break locas now and they 12 shouldn't have to.
They should be able to be more focused on 13 realistic conditions.
14 MR. MICHELSON:
I thought they were symptom-based, 15 not event-based.
16 MR. WILLIAMS:
They are symptom-based, but they are 17 directed to all events.
l 18 MR. MICHELSON:
The event, of course, -- well, 19 MR. WILLIAMS:
They must accommodate all events that 20
'the plant is licensed against, all design basis events. The 21 instructions do not depend on what event happens --
22 DR. KERR:
Excuse me. I want to make sure I j
I 23 understand your statement.
You say that one should not have to l
24 undertake against large break locas.
This means, for example, 25 that you'd be willing to eliminate that part of the ECCS that l
Heritage Reporting Corporation (202) 620-4000
90 l
1
' deals with large volume flow?
U) 2 MR. WILLIAMS:
That's what this is. That's what this I
3 slide right here talks about.
Now, I'm not saying we'd ever 4
get to that point, but I'm saying that it's something that we 5
need to look at because of the potential benefits.
Yeah.
6 MR. KERR:
But you would be willing, if permitted, to 7
eliminate any consideration of large break locas?
I'm not 8
talking about.an instantaneous double-ended pipe break. I'm 9
just talking about a break in a large pipe.
10 MR. WILLIAMS:
If the studies -- if I could convince 11 myself --
12 DR. KERR:
I thought you had already convinced I
13 yourself.
14 MR. WILLIAMS:
No, no.
15 DR. KERR:
No, you haven't yet.
16 MR. WILLIAMS:
Right.
17 DR. KERR:
Okay.
18 MR. WILLIAMS:
Correct.
19 DR. KERR:
I retract my question.
I' thought you said 20 that the operator shouldn't have to protect against large break 21 loca, that this'was a considered opinion. I misunderstood you.
I 22 MR. WILLIAMS:
Okay. I'm sorry that I led you to that 23 misunderstanding.
24 MR. WARD:
An incredible event.
.25 MR. WILLIAMS:
As I indicated, to preface all my Heritage Reporting Corporation (202) 628-4088 O
G 91 1
remarks,.we haven't been down the road to justify all this yet.
r i
2 These are all supposing that we can get down.that road and j
3 justify. That road is not going to be traveled if the door is 4
closed to pursuing it further.
5 MR. WARD:
I think.what he's saying is that -- well, 6
are you saying you.think there's potential that you could 7
convince yourself --
8 MR. WILLIAMS:
Yes.
9 MR. WARD:
-- and perhaps others --
10 MR. WILLIAMS:
That's correct.
11 MR. WARD:
-- that a large break loca doesn't have to 12 be considered in this sort of thing?
13 MR. WILLIAMS:
That's correct.
14 MR. WARD:
Okay.
15 MR. WILLIAMS:
There is potential, and the potential 16 has not been pursued at this time.
17 MR. CATTON:
When you talk about reduced requirements 18 of loca analysis, what do you mean?
19 MR. WILLIAMS:
Things like reducing the number maybe 20 to zero of safety injection tanks that are required to be 21 operable or if some have to be operable, the volume and 22 pressure requirements in safety injection tanks, reducing the 1
23 number of lipsy pumps that have to be operable, maybe reducing 24 the operability requirements to shut down cooling requirements.
25 MR. CATTON:
Do you have a realistic loca code that's Heritage Reporting Corporation (202) 620-4088
l 92 1
blessed by NRC yet?
()
2 MR. WILLIAMS:
Combustion Engineering does, yes.
3 MR. CATTON:
It's been blessed by NRC?
4 MR. WILLIAMS:
Well, wait a minute.
You said 5
realistic.
We have an Appendix K approved code, yes.
6 MR. CATTON:
Best estimate code?
7 MR. WILLIAMS:
A best estimate code is in -- has been 8
submitted for review.
9 MR. CATTON:
Because you really can't do some of 10 these steps until you have that.
11 MR. WILLIAMS:
Right, and those are the steps you 12 take, if we continue to pursue these things.
That's correct.
13 There's no question that there's a lot of work 14 involved in going down this road. We're talking about the
[
potential benefits of going down that road.
15 16 Reduced containment building cooling capacity. We may 17 be able to reduce the number or the performance requirements on 18 those coolers, including containment spray in that box with the 19 coolers. Increased margin to safety system actuation by 20 lowering the uncertainties that are tacked on to the set 21 points. Things such as safety injection system and emergency 22 feed water actuation.
23 Relaxation of tech spec requirements on things like 24 the number of pumps and coolers that have to be operable.
25 Things such as the ultimate heat sync which now most cases has Heritage Reporting Corporation (202) 628-4000 0
(.
93 i
I.
1 a maximum temperature requirement.on it that could be' lowered C
)
2 if it's limited by things such as cooler performance in the 3
containment building and allow you to continue to operate at 4
full power operation during times like last summer'when some 7
5 plants had to drop their power level to accommodate the 6
ultimate heat sync temperature limit, and the bottom line is 7
you've got increased operational margins between the 8
performance of your components and what's required. You 9
minimize the challenge to safety systems by decreasing the 10 uncertainties that are tacked on to the set points.
11 You minimize the power reduction and forced outages 12 that are caused by the requirements to have these things 13
' operable or the parameters to which they're limited. You 14 enhance plant operability and flexibility by -- I guess I
{}
talked to one operator last week and he said, boy, this sure 15 16 would be nice because if I didn' t have to go check on this and 17 do surveillance on that, because it wasn't required anymore, I 18 could spend my time doing more productive things, like 19 discussing. strategies and paying attention to things that are a 20 little more realistic.
21 And, again, put all these together and you got our 22 aim at enhancing safety.
I guess all of this -- we' re talking 23 about conjecture, things we might be able to do, things that 24 have enough potential benefit that we'd recommend that this 25 option continue to be pursued. IJo promises that it will ever Heritage Reporting Corporation (202) 628-4888
l_
\\
l 94 i
1"
' pan out. No promises that these benefits will actually happen, 1()
2 but they are promising enough that we would recommend that'they 3
continue to be pursued.
4 MR. WARD:
That recommendation is to whom?
5 HR.. WILLIAMS:
Well, it's primarily to the staff to
.6 keep'this open.
To continue to pursue it as much as they do-7 other incremental safety improvements. Their recommendation 8
appears to be, well, it's not worth pursuing at this time, and 9
we would like to'see that decision modified to continue to j
10 pursue it, to work with industry on it, to-provide incentives 11 and encouragement'even to go down this road, at least till it 12 becomes obvious that there's no pay back and I don't think_that 13 will be the case completely.
14 Some of those roads will end up with roadblocks
[ }
15 probably.
16 MR. MICHELSON:
At least part of the burden is I 17 think with you to show that it is worthwhile to pursue, and if 18 you want it pursued, you have to go far enough to demonstrate 19 its worthwhileness, and, of course, today, we haven't seen much 20 of that demonstration.
21 MR. WILLIAMS:
Right.
22 MR. MICHELSON:
You talk about all of the' things you I
23 could do or would do or something, but you need encouragement, l
24 and I'm not sure that's the way it works. I think the way it i
25 works is you go out and make a case and then you come to the Heritage Reporting Corporation (202) 620-4000
95 1
NRO'with the case.
()
2 MR.. WILLIAMS:
The way it works.is we go out and 3l
' spend.a:few million' dollars making the case to the NRC and.they 4
said we told you we weren't interested in that or we come to 5
them and.they say, it will cost you two million more to review 6
it.
7 What we need is some promise of success. No doors 8
closed.-
9 MR. MICHELSON:
Success in what?
10 MR. WILLIAMS:
That if we do pursue this and invest 11 our time and resources in justifying it, that there's some hope 12 that it will be approved for application.
13 MR. MICHELSON:
Well, I think what you can only hope 14 for is a promise of a fair hearing.
15 MR. WILLIAMS:
Absolutely.
And at this point, we're
{
16 promised no attention from what we' re seeing here.
17 MR. MICHELSON:
On what basis do you have the belief 18 there's no attention?
19 MR. WILLIAMS:
What I heard this morning in the 20 presentation.
I 21 MR. MICHELSON:
I guesa I didn't hear the same 22 presentation. I didn't get that impression.
23 MR. WILLIAMS:
Well, --
24 MR. MICHELSON:
If you can make a case, I'm sure the 25 staff would listen. At least I didn't hear anything that says
(
Heritage Repo rting Corporation (202) 620-4000
()
96
.1 the staff won't listen if you.can.make a case.
I think what
. ry L( j
-2 they said is'if you don't.have a case, they're not going _to,try 3
to make it for you.
4 MR. WILLIAMS:
Well, we'd like to work with the staff 5
on this sort of thing.
6 MR. MICHELSON:
I don't think they need to work with 7
you on it. I think you'need to make.a case and then they need 8
to give it a fair hearing.
9 MR. WILLIAMS:
Is improving safety not part of --
10 MR. MICHELSON:
I haven't heard much yet. I've heard 11 a lot of speculation.
12 MR. WILLIAMS:
Absolutely.
13 MR. MICHELSON:
You haven't made a case for how you 14 improve safety.
I haven't heard a single --
15 MR. WILLIAMS:
Right.
16 MR.'MICHELSON:
-- hard fact case made yet.
When you 17
. generate your hard fact case, then you bring it forward, and if 18 they don't listen, maybe the ACRS will listen.
19 MR. WILLIAMS:
Well, that's one of the. points I made 20 at the beginning.
We don't have hard facts because we haven't 21 gone down the road, and in order to go down the road, we need 22 some hope of some cooperation and encouragement from the staff.
23 We don't want to waste our resources on this when we' re going 24 to have to throw it all away.
25 MR. WARD:
Bill?
Heritage Reporting Corporation (202) 620-4808 O
1 97 1
DR. KERR:
Maybe you have answered this question and,
, g)
(
2 if so, I apologize, but have you done a full scope PRA or any 3
sort of PRAs for your plants?
4 MR. WILLIAMS:
We' re in the process.
5 DR. KERR:
Earlier, I believe I got the impression 6
that you thought it was very likely that large break locas or, 7
in fact, maybe locas generally did not pose a significant risk.
8 MR. WILLIAMS:
That has been what I have been led to j
9 believe without any actual personal knowledge, i
10 DR. KERR:
Okay.
Well, let's suppose that that's the 1
11 case. Then, it seems to me if that is the case with existing 12 equipment that it would make more sense for both you and the 13 staff to concentrate on things that perhaps do pose significant 14 risk and, so, I'm at a loss to see what large leak before brea).
('
15 has to do with anything. Forget leak before break and start V) 16 looking at other things that may pose some risk.
17 Tell me what I'm missing.
18 MR. WILLIAMS:
Okay. What leak before break allows us i
i 19 to do is focus our efforts on the things that do pose a risk.
l l
20 By eliminating from consideration the large breaks.
h.
21 DR. KERR:
But you're not here to spend a lot of time i
l 22 on large break loca.
Now, if you have installed ECCS and I
23 procedures and you surely must have the existing regulations, 24 what is going to occur that will free you up from a lot of --
l l
25 MR. WILLIAMS:
We spend a lot of time accommodating l
Heritage Reporting Corporation (202) G20-4000 l
l l
98 j
1 the regulatory requirements to accommodate large break locas.
.O 2
see o e 1ee er ei e rieeri#e eme we
-e re eei=e te e 11 eer 3 -.
operators what to do with instrument errors based on large 4
break locas.
5 We spend a lot of time testing and doing surveillance 6
on safety injection tanks that are there for large break locas.
7 We do a' lot of time ensuring that our pump performances and low 8
pressure-safety injections --
l 9
DR. K E R It:
Well, from the experience of the 10 utilities, it seems to me you need a few things like this.to 11 keep operators awake.
If you eliminate those things, they just 12
-- they may spend, you know, the full shift sleeping.
13 MR. WILLIAMS:
I find those situations when I read 14 about them fairly incredible. The environment at our plant is I
-15 significantly different than that.
Our operators sit around 16 and discuss accident strategies sometimes. They discuss and 17 look'at things related to which instruments to use. They work 18 on upgrading procedures --
]
19 DR. KERR:
Now, they can't discuss accident strategy 20 in very great detail if you haven't completea your PRA yet 21 because until you have done that, you maybe can do a lot about 22 large break locas and small break locas, but you don't really j
1 23 know in detail how your plant performance is likely to impact l
24 on risk unless you have a very well developed intuition.
t 25 MR. WILLIAMS:
I think we have from a deterministic l
Heritage Reporting Corporation (202) 628-4000 O
i
'i i
l 99-l 1
standpoint some pretty good ideac about the effects on process
()
2 parameters and the appropriate reactions to take when things L
3 might happen. Maybe not how likely they are to happen, but 1
4 certainly ways to go about mitigating them, and that's the kind 5
of things I'm talking about with respect to strategies.
j.
6 DR. KERR:
Well, I hope so.
l 7
MR. WARD:
Okay. Thank you, Mr. Williams. Very 8
informative.
p 9
Let's see. Our next speaker is -- Mr. Siegal, did you 10 have something else you wanted to close with?
11 MR. SIEGAL:
Ho. I just wanted to leave the area 12 clean.
13 MR. WARD:
All right. Thank you very much.
14 Let's see. Gerry Neils'from Northern' States Power is
- L5 our next speaker. He'll talk about their BWR situation.
{
I 16 MR. NEILS:
I would like to talk a little bit about 1
17 the potential benefits and some of the problems lacking those 18 benefits for leak before break applications for the 19 circumstance of environmental effects of high energy line break 20
'outside containment.
21 Before I get into that, though, I'd like to comment 22 about three or four things here.
One is that I am very much in 23 agreement with Mr. Williams, who raised the point that 24 expending the resources to justify a case lacking any l
25 encouragement at the end point before you begin is a rather Heritage Reporting Corporation (202) 620-4000 0
i r
100 1
hazardous' occupation,.and that 10, I think'some~ rule changes I
I
()
2' are necessary in GDC-4 to provide ~for other applications should 3
the staff be satisfied with the technical support for those l'
l 4
other. applications, particularly in the environmental area.
]
L 5
For my own part, ~I think attempting to change the 1
6 large break loca criteria in Appendix'K from my perspective 7
would be a rather hazardous occupation, but 1 think that~there 8
is merit in addressing leak before break, the rate of breah 9
development.for those large break locas.
10' We heard the presentation o* an analysis relative to 11 break size development for large dry containment earlier.
I'
-12 think the results of that analysis would have been very.
13 dramatically different in terms of peak containment pressures 14 and loads upon.the containment had that analysis been presented 15 for pressure suppression containment.
16 As I say, having lived with the Mark I containment 17 owners' group from its inception to its conclusion, I think what.
18 you find is with pressure suppression containment, where the 19
' heat sync is immediately available, the large break blow down 20 of the' dry well to the wet well is, in terms of peak presnure 21 and in terms of hydro-dynamic load upon that wot well, are very 22 significantly influenced by the rate of break develop: tant.
23 One other thing I' d like to point out, having been 24 involved in the BWR owners group for IGSCC research very 25 heavily fron '82 until its demise at the end of last year, as Heritage Reporting Corporation (202) 620-4000
()
I
V.
101
,1
'its chairman for quite a few years, I'd like to point out' that
()
2 the leak before break criteria as applied under the broad scope rule was never 'xceeded for any IGSCC' crack identified-either 3
e 4
'in the field.or in the pipe. test laboratory during that whole 5
program.
6 The other thing not entirely facetiously, I am 7
wondering if leak before break is not to.be applied in cases 8
where there are degradation mechanisms present, such as IGSCC, 9
fatigue or erosion corrosion, or, more particularly, a 10 potential for those degradation mechanisms,'I'm wondering 11 what's.left. I don't know about any piping systems where none 12 of those are present.
13 Now, I think we should give some serious 14 consideration to a different treatment for not only the 15 mechanical effects but also the hydraulic -- environmental 16 effects associated with high energy line break outside 17 containment because here we are talking about the potential i
18 damage to equipment whose purpose may be to prevent or mitigate i
f 19 an accident rather than talking about leak before break for 20 primary pressure boundary equipment and piping where we're 21 talking about the effects after the. loco accident has occurred.
22 It's a matter of before and after accident that I 23 think some consideration should be given to.
24 I think we should look at -- if we consider high 25 energy line break outside containment, the 1dne break Heritago Reporting Corporation (202) 620-4000 0
i 102 1:
consequence harsh' environment that's created thereby, and then
. i( )
2 the problems and costs, associated costs, that this creates for 3
' equipment environmental qualification outside containment.
4 I think there should be some consideration to apply 5
leak before break either with or without some possible l
6 augmentation to that in terms of ratios to allowable stresses 1
7 and/or additional inspections to further reduce the break
'8 probability whose environmental effects one would have to deal 9
with to avoid the harsh environment assumption, and, generally, 10 for' instrumentation outside containment, we're talking about a 11 mild environment or a harsh environment. It's kind of an off/on i
12 switch, and the difference between those two for environmental 13 qualification of equipment can be a very large number.
14 At that basis, we could avoid continuing unreasonable
{
costs for environmental qualification equipment.
l
>15 16 The thing that should be recognized is that for 17' compliance with equipment environmental qualification, almost 18 perfect is a failure when it comes to the people that enforce 19 the rules.
j 20 MR. MICHELSON:
What do you mean by that?
21 MR. NEILS:
One little nit can be an excuse to shut 22 down a billion dollar power plant, a multi-billion dollar power 23 plant, as though that line break is going to cccur to impose a 24 harsh environment on that ins'.rument right at this instance.
25 Now, there have been and will be continuing l
Horitage Reporting Corporation j
(202) 620-4000 I
()
103
~
~,
l'.
discoveries 'of. individual instances of environmental
' qualification.'non-compliance. T ey do occur,and they.are nearly 2'
-i
~3..
always expensive..Sometimes, at least in this indiOidual's 4i
. opinion,..the resulting, benefit l's a little. questionable.
5 6
1
\\
7 8
'9 10.
11
'.12 :
13 14
'; 15 -
'16 17 18 19 20 a
21 1
.x I'
)
Heritage Reporting Corporation e
I (202) 620-4000 l
O 1
l 1
__.___ _ 9
104 1
MR. NEILS:
Recognizing that one accepts these im(,)
2 instances of discovery of noncompliance on a random basis, from 3
time to' time in each plant, the costs can be very.large for the 4
industry at large.
5 But I'd like to tell a story of three examples where 6
that's occurred at our plants.
Two at our PWR, one at our BWR.
7 One example is associated with the harsh environment related to 8
the. turbine drive steamline break in the auxiliary feedwater 9
pump rooms.
Each at two.
Another one is associated with the 10 postulated main steamline break in a primary auxiliary building 11 in a PWR.
And a third one was associated with postulated line 12 break of elements of both feedwater and condensy lines in a 13 turbine building compartment in our BWR.
14 MR. MICHELSON:
Now, are these examples because you
}
15 believe in each case that you could have applied leak before 16 break?
17 MR. NEILS:
Yes.
18 MR. MICHELSON:
So your thinking of leak before break-19 on feedwater lines, for instance, as well?
l L
20 MR. NEILS:
Yes, yes.
l 21 MR. MICHELSON:
And you are going to argue-you are 22 going to tell us why you don't get waterhammer potentials in 23 such lines and so forth, because that's how you exclude them--
24 that's how you qualify them for leak before break.
Unless you 25 are challenging the leak before break rules, and that's the Heritage Reporting Corporation (202) 620-4000 1
105 1
difference--
()
2 MR. NEILS:
Let me describe the cases here that I 3
mentioned.
4 MR. MICHELSON:
Okay.
5 MR. NEILS:
The-one case of a steamline break and the 6
resultant harsh environment that had to be assumed in the 7
auxiliary feedwater pump rooms.
In this case, for each of the 8
turbine drives there were fifteen feet of steamline from the 9
room wall sleeve to the turbine stop valve.
Fifteen feet of 10 line.
11 MR. MICllELSON:
Is that the RPSI pump?
12 MR. NEILS:
No, no.
This is a turbine-driven 13 auxiliary feedwater pump in a PWR.
14 MR. MICHELSON:
No, on the main feedwater line.
15 MR. NEILS:
Pardon?
16 MR. MICHELSON:
On the main feedwater line?
17 MR. NEILS:
No.
18 MR. MICHELSON:
Oh, this is on your PWR.
I thought 19 you were talking about your boilers.
20 MR. NEILS:
Okay.
All right.
21 MR. MICHELSON:
You're right.
I'm wrong.
22 MR. NEILS:
I have the problem of switching gears 23 from time to time too.
24 MR. MICHELSON:
You were back and forth and so I 25 thought you were still on feedwater--
11eritage Reporting Corporation (202) G20-4000 0
l r
106 1
MR. NEILS:
We're back in the auxiliary feedwater
()
2 pump room in a PWR.
The high energy line of concern is fifteen 3
feet of line from the wa11' sleeve entering that line up the 4
stop valve for the turbine drive.
Discovery here that we had 5
not addressed the potential for a high energy line break in-6 that short length of line.
7 We did go through the exercise to do a leak before 8
break analysis.
It was accepted on an interim basis as a 9
justification for continued operation until the next major 10 scheduled outage.
11 The solution at that time was to relocate the stop 12 valves for each of these two turbine drives to outside the 13 equipment room.
That fifteen feet of line between the stop 14 valve and the turbine is not normally pressurized.
The cost to 15 cure was a million and a half bucks.
That hurts.
16 MR. MICHELSON:
Now, why do you think that was 17 unnecessary?
18 MR. NEILS:
Because I think the consequence of that l
19 line break is very different between the consequence of a link l
20 break in a primary system inside containment.
And I think the 21 probability is much smaller for that line break than is 22 arbitrarily assumed in terms of the harsh environment you have 23 to deal with.
24 MR. MICHELSON:
Do you include a steam generator 25 overfill in that consideration?
Heritage Reporting Corporation (202) 628-4888
-O
m--._
107 o
1 MR. NEILS:
This particular application--I think each
<*s.
l( )
2 one of these cases has got to be dealt with in a case-by-case 3
' application.
4 MR. MICHELSON:
And'then in'your case did you look at 5
_ steam generator overfill as a possibility for leading to 6
rupture of that line?
7 MR. NEILS:
No, I didn't.
No, I didn't.
8 MR. MICHELSON:
Okay.
That's why I don't--
9 MR. NEILS:
You've apparently got something stuck, 10 hung up here on the steam generator overfill.
11 MR. MICHELSON:
Yeah, the water passes through the 12
.very steamline you are worried about and then you open that 13-turbine and you accelerate a column of water through that 14 steamline into the turbine and that line--
15 MR. NEILS:
If you want to assume that it's readily--
l 16 that it's a highly probably or a reasonably probable 17 occurrence, yes.
18 MR. MICHELSON:
It depends on your instrumentation on 19 your steam generators as to whether it's even safety grade for-20 preventing overkill and that's been a generic issue on most of 21 the older plants.
You'll probably find it's non-safety grade.
22 MR. NEILS:
Well, having--well, I don't know if the 23 experience is worth anything to you or not, but, say, having 24 quite a few years on these two PWRs--
25 MR. MICHELSON:
Well, steamline overfilling has Heritage Reporting Corporation (202) 620-4000 0
7_.
1 1,
108 1
occurred on several plants in the past.
They-were just lucky, I
2
~of course, they didn't start the auxiliary feedwater turbine 3
when the water was in the steamline.
4 MR. NEILS:
The second case here that I'd like to
~
5 raise is a main steamline break in a primary auxi1iary 6
building.
The case involved a circumstance where one of the 7
two main steamlines for one of the two units came through the 8
containment shield building penetration to an upturned elbow 9
and then through the foresleeve above.
10 The amount of piping at this floor level, the zone, 11 exposed was the elbow and ten feet of pipe, at max.
Ten feet 12 of straight pipe each side of the elbow combined.
'13 Again, leak before break was satisfied here and used 14 as a justification for continued operation to the next outage.
15 The problem had to be cured without leak before break 16 justification at that time prior to restart.
17 The solution involved relocation of some instruments, 18 break temperature profile of spatial analyzation and equipment 19 heat. sink capacity calculation to go with it in some cases.
20 Compliance was achieved at a cost of about three quarters of a 21 million dollars.
22 The third case involved elements of feed pump suction 23 and feed pump discharge for each of two feedwater pumps in a 24 BWR.
For just short elements, of each of those four pipes that 25 went through a ten-by-twenty room before going into the IIeritage Reporting Corporation j
(202) G20-4000 O
l
109 I
l' condenser room,.through the condenser wall.
().
2
. Compartment pressurization was the issue here.
A
-3 line break would potentially breach the concrete wall on one 4
side of the room and the consequence assumed from that 5
postulated event would impose a harsh environment on both 6-
' divisions of a redundant safeguards application motor control 4.
7 centers.
8 Again, leak before break for all four line elements 9
was satisfied and used for a justification for continued 10 operation'.
11
.The solution in this case was to seismically support 12-all four elements-of the piping to their terminal ends at the 13 upstream and downstream feedwater heaters so that interim 14 breaks did not have to be considered at every weld.
In essence, we moved the intermediate break outside the room and
{ }
15 16 that problem was cured at a cost of about $1 million.
17 How, to just put some of these things into 18 perspective of what they mean.
This is just a small part of a 19 very large picture.
That is, if we. look at what is happening 20 to the depreciated book value of these plants.
This happens to L
21 be Prairie Island.
It includes both units.
They went on line l
l 22 at the end of ' 73 and the end of '74 and after depreciating 23 since the beginning of '74, through fourteen years to 1988, and l
1 24 surprise, surprise.
The depreciated book value is now greater i
25 by a small amount than it was originally booked at.
This is Heritage Reporting Corporation (202) 620-4888 t
N s
7110-1~
not.a turnkey plant.- The top dotted line on this slide is $400-
{
2 million.
We bought.them at a good time.
3.
To;give you some idea.what a turnkey plant--
'4 MR. WARD:
^I've<still got a car I bought'back'then--
5 MR. MICHELSDN:
I'm not sure--
6 MR. NEILS:
Now, wait a minute. 'Let me finish.
7 MR. MICHELSON:
What's your argument'though because 8
that's changed?
What's your problem with it?
9' Mt. NEILS:
This11s an indication of what a BWR that.
10 was a turnkey plant looks like.
The depreciated book value.has 11
'now depreciated down to approximately three times its initial 12 capitalization the date of operation.
13 Now, the only reason I point this out and try to show 14 that perspective is where we are talking about things that some 15 of us would question in terms of the real safety benefit 16 relative to the cost to comply with the requirements as they 17
, stand,' Those' costs don't go away.
And when the rule says 18 you've got to do it, then a cost benefit argument doesn't do 19 you much good if you're the licensee in a position <of crisis.
20 Now, I think there's a reasonableness to treating the 21 issues of high energy line break outside containment in a 22 different perspective than the issues of high energy line break 23 inside containment particularly if we're talking about a 24 difference between primary pressure boundary versus auxiliary 25 piping outside containment.
Heritage Reporting Corporation (202) 620-4808
.0;
111 l'
That's about:all I've got to say.
g J( )
2 MR. MICHELSON:
In doing this, looking at outside a-3 containment where.I gather you are saying that it's probably of 4
lesser safety concern than inside a containment because it 5
isn't the primary pressure boundary, although I'll point out'on 6
your boilers, in essence it.is the primary pressure boundary 7
out through the reactor water clean up that would potentially 8
rupture'out through the HPSI line, out through the RPSI lines.
9 These are all looking-directly at the reactor and you are now 10
. depending.upon certain valves that must close or you've got a 11 major disaster on your hands.
12 MR. NEILS:
Redundancy and diversity in just about 13 overy case.
14 MR. MICHELSON:
Yeah.
Well, we have very definite 15 reasons to believe maybe the valves are not even as functional 16 we thought they were.
But I'm trying to determine what your 17 argument is from the viewpofnt of lesser safety significance.
18 When you.do your breaks outside of containment, do 19 you chase the steam around the building to see what it's doing 20 to the equipnent in all other the areas of the building?
Like 21 if a HPSI line were to break at Monticello, have you done the 22 calculation--
23 MR. NEILS:
That's part of the rules.
You've got to 24 chase your vent pans.
You've got to chase your compartment 25 pressurization.
You've go to chase small cracks.
Heritage Reporting Corporation (202) 620-4000 0
a L
a 112-L 1
. MR. MICHELSON:.Have you goalified all the equipment
-( )
2, in-the building for the conditions.that are in the building as 3
a result of that steam release?
d4 MR. NEILS:
Yes.
I think we've reasonably done-that.
5-MR. MICHELSON:' And if you've done that, then'you 6
realize that if the valves don't close in fifteen to twenty 7
seconds, like on a HPSI line, you've got a major problem with i
8 the, engineered safety. features required to continue.to cool the i
9 core.
.j 10 MR. NEILS:
Now, wait.
Let me make a point here.
I-
~
11
'think-you'see,. my position is that one should take this kind.
12 of a case and take a hard look at it for differential l
13 treatment, for high energy line break, harsh-environments-l 1
14'
-created by a presumed high' energy line break outside of I
15 containment, and I think they should be taken on a case-by-
{
s
.16 case basis.
But in order to do that, I think there should i
17 first'be an amendment to the rule to make that possible so that 18 you don't have to fight an uphill battle for an exemption that 19 the rule discourages.
)
20i MR. MICHELSON:
Well, in order to justify a rule, 21 sometimes people need to see what kind of--you know, maybe the 22 rulomakers need some encouragement for you to demonstrate what 23 really can be done.
To do that you have to make a case.
I 24 haven't heard the case here.
I've heard that you've got a 25 problem and it costs you a million dollars to fix it.
But that Heritage Reporting Corporation l
(202) 620-4000 j
()
1
+
)
5 r
i M
113 1
1D isn't making a case for it.
You really'have to begin to po3nt
[
2
. out--you've got to.come forward I think with,.what do you want-
'3 toLdo exactly?
And then look to-see what change in a rule--if 4
a1 change inna rule is even needed.
1 5
MR. NEILS:
There's another side to the story.
~6 Another-side to the story.
And that is the ironclad 7
' requirement to deal with the harsh environment consequence of high energy line break outside containment'has had dearly 8
c 9
little justification for being in the rule in the first place.
10 And if it has,:I would like somebody to quote it to me and'show 11 it to me.
12 MR. MICHELSON:
Well, this is not the place to' debate 13 the question of environmental needs for environmental 14 qualification.
I think that'c been debated extensively and
})
15 justified extensively.
i 16 MR. NEILS:
I wouldn't debate the need for 17 environmental qualification..But I would debate the need to i
18 assume the harsh environment is created in all of these cases.
19 MR. MICHELSON:
Oh, I think you have to be--maybe we 20 need a more realistic calculation of the environment and a part-1 21 of that is a more realistic estimate of what's happened with 22 size of breaks and whatever.
But I think you need to come 23 forward--the encouragement has got to be, you know, it's a two-24 way street.
I don't think you ever get a rule change before 25-you even come forward with a demonstration of a need.
l l
Heritage Reporting Corporation (202) 628-4888
_____________m_
.m
114 l
1 MR. NEILS:
I would cuggest, Mr. Chairman, that the
~()
2 cases cited demonstrate the reasonableness of an economic need.
3 I think if there is willingness to consider the proposition I i
4
= put forth, then I agree that we in the industry have-a 5
reasonable requirement to. demonstrate a case that with the leak 6
before break criteria and potentially some augmentation of it 7
to further reduce the probability of a break, that then such 8
change might be approved.
l 9
MR. MICHELSON:
But see, we can't deal with the 10' economics because that's not a public health and safety issue.
11 Unless you can--
l 1
12 MR. NEILS:
Well, once you're on the public payroll, f
13 you have an obligation to deal with economics 14 MR. MICHELSON:
Well, that's a--
15 MR. NEILS:
Well, it's part of the energy complement 16 of this country.
17 MR. MICHELSON:
You'll have to debate that with the 18 lawmakers.
R 19 MR. CATTON:
It seems to me that at least I would, 20 have liked to have seen a calculated environment as contrasted 21 with the one that they had to deal with'and then maybe.then i
22 complain.
23 MR. MICHELSON:
- Yeah, I' d like to see something firm l
24 to deal with.
But he needs encouragement and he wants the rule 25 changed first.
l I
I Heritage Reporting Corporation (202) 620-4000 O
h, 115-1
~MR.
WARD:
Okay, gentlemen, I'think we've' heard
()
2-there's some sort of an impasse.
I'm not quite.as convinced as 3
, Carl seems to be that it's all on one side.
But there's a 4
' problem here.
1DR. KERR:
I mus't say I'm also' not convinced that we
'5 6
should completely ignore economics.. I think if Congress.had 7
. wanted economics to be completely ignored, they would have not 8
approved nuclear power.
1 9
MR. WARD:
But I think they created the NRC then to--
j' 10 because they did chose to ignore economics I guess.
-Well, I 11 don't know, I get pretty damn frustrated on some of this stuff 12 sometimes and I think the Committee has made its contribution 13 to'the decline.
14 DR. KERR:
None of those present, of course..
15 MR. WARD:
No, n o..
Past Committee.
16 Okay.
I think our next speakers apparently have not 17 shown up. 'Have they?
Oh, here they are.
18 DR. KERR:
But don't we have a rule that people who 19-don't show up in time to listen to the presenters who, precede 20 them can't say.anything themselves?
- 21 (Laughter. )
./
22 MR. WARD:
They know everything we were going to say.
23 We're going to take a five-minute break now.
1 24 (Whereupon, there wac a five-minute break.)
25 MR. WARD:
Our next speaker is Mr. McIntyre.
IIeritage Reporting Corporation (202) 620-4808 O
if l
(s 116 1
MR. McINTYRE:
My name is Brian McIntyre and I'm the
()
2 manager of Product Licensing for Westinghouse'.
'3 And what I've come down to talk about is to explain--
4 we wrote a position paper where we looked primarily at the 5
impact of leak before break on ECCS, and explain what we did 6.
in-house to arrive at that position.
7 And basically what we did is we went back and we i
8 looked at all the plants we've got operating.
We said are 9
there some changes that we.could make, reductions in set 10 points, changes in operating margins, benefits that we could 11 get if we went back and looked at the operating plants we've o
12 got today from applying leak before break not only to the ECCS 13 systems but also to the steamline break.
14 And we looked at the safety injection systems.
We L
15 looked at ways that we could simplify things, take things out, 16 or do some sort of tech spec relaxations, LCO increase in 17 times, and things like that.
18 We looked at the containment systems for things like 19 containment spray, fan cooler, reduction in capacities so we 20' get more equipment out of service.
And we looked at 21 environmental qualification again both for LOCA and steamline 22 break.
Because there are going to be some reductions in the 23 containment pressure, reductions in environmental temperature 24 as a function of this.
25 We also looked at what the impact of this would be on Heritage Reporting Corporation (202) 620-4808 O
m
~l 1
117
,1 Lnew plants.
We've got a couple of plants right now.
The APWR,
[)'
2 which is also known as the SP-90,-which is sort of an
.3 evolutionary design.
And also the.AP-600, which is an advanced l
l
~4 passive design.
l-5 And we looked at it again two ways.
We looked at 6
what'is go'ing to be the impact'if we-used the Appendix K models 7
that we have today and is there going to be any benefit from 8
going to these best-estimate LOCA models that the rule, change 9
is going to allow.
10 Right now the rule says that there are some cases 11 that you can look at some of the smaller lines for the purposes 12 of going.through a snubber reduction program and pipe 13 restrains.
And a few plants have applied for that.
14 Westinghouse has done some small amount of work in that area.
15 Again, we're the.HSSS vendor.
We don't do a lot of work on the 16-balance of plant side or on the AE, for basically the things 17 that-are traditionally the AE ocope.
And that's one reason 18 that our comment letter intended to be so focused.
19 Now, the proposed change, as we understand it, looks 20 at ECCS performance for all the sizes up to the largest thing
'21 that you can't disposition by a leak before break.
And it 22 applies also to the carbon steel main steamline.
- Again, I
23 looking at the breaks beyond those that you can't deposition by 24 leak before break.
25 If you look at our current loss-of-coolant accident l
Heritage Reporting Corporation (202) 620-4000 0
118 1
considerations, basically what we do is we look at a spectrum A()
2 of breaks as required by Appendix K.
There are small breaks 3
and there are large breaks.
And basically we cover everything 4
from one square inch up to a full double-ended guillotine break 5
of the main reactor coolant pipe.
6 And we have separate models that we use for that.
7 There's a large break model for things greater than one square 8
foot where basically it's dominated by the inertial effects and 9
that's called the Satan Code.
Again, we're going through a 10 change process right now to more advanced models that I'll talk 11 about in a couple of minutes.
12 And traditionally for a large break, the applied 13 temperatures are very near 2200 degrees, 2100 to 2200 degrees.
14 And what we do is we adjust the peaking factor, which is a tech
(~)T spec that will give the plants either a lot of operational 15 u
16 flexibility or restrict your operational flexibility to get a 1
17 right answer.
Right being less than 2200 degrees.
18 Now, if that goes away, if a large break, the very, 19 very large breaks, we'll move down probably the next size down, 20 something between large breaks and small breaks, or the 21 intermediate breaks.
And they are what Westinghouse considers 22 somewhere between less than one square foot but greater than an 23 eight-inch diameter hole.
And they are at sort of a mixture of 24 inertial effects and gravity effects.
And we don't look at 25 those a lot.
Really the only time we do that we when we're i
Heritage Reporting Corporation (202) 620-4888 l
119
~
i 1
.getting a new model approved.
One is that the codes don't run
]
( }-
2~
really what'we consider in a cost effective manner.
We're 3
talking hours Hof cray time tua do one of these calculations.
)
4 And if you go'through and draw kind of what we're-5 looking at here, _that is the calculated peak quiet temperature-6 versus the break. size, which is pretty low, the small breaks l'
l 7
tend.to be down in here.
Where these would be like the one 8
square, two, three, four square inch breaks.
And it probably 9
' peaks for most Westinghouse plants somewhere between the two 10 and the four-inch break.
And the quiet temperature drops down.
11 12 And somewhere the intermediate breaks will be out in 13 this area.
And then the large breaks, the
.4, the.6 and
.8, 14 1.0 guillotine breaks, are clear out on that side, so if you 15 chop this off for.some reason, and then we would have to start 16 looking at breaks down in that area.
Because there's a good 17 chance that they may be higher than small break cases would be.
I 18 MR. WARD:
I don't understand what you just said.
I 19 mean you've drawn the curve.
Are you really saying that the 20 dip in that curve is a dotted line or an unknown area or 21 something?
Why have you drawn the curve that way?
j i
22 MR. McINTYRE:
It's something that we calculate'once.
23 I'll use an example.
We just stood up here for a couple of 24 years and talked about the "no trump code," the one that we had
.25 approved for small break.
Heritago Reporting Corporation (202) 628-4888 O
120 1
And we do the calculations for the two, three, four, lll 2
six and eight-inch breaks.
Everyday we submit them.
People 3
submit them on their dockets.
l 4
The ten-inch break, the half-square foot and the one-5 square foot with no trump, we did those once.
What we did was 6
we went through and we took the typical plants, actually I 7
believe it was two typical plants.
A four-loop and I believe a 8
three-loop plant.
We did those calculations and demonstrated 9
that, lo and behold, the intermediate breaks for those plants
\\
10 were less than the calculated peak temperature.
We showed that 11 they were not limiting in a generic sense.
We traditionally 12 don't go through and calculate that whole cotton picking curve.
13 MR. WARD:
I guess I don't understand--
14 MR. McINTYRE:
We calculate this part of it very, ggg 15 very frequently, and we probably calculate, you know, that part 16 of it very frequently.
17 MR. WARD:
So you are saying you'd want to put a big 18 uncertainty ban on that part in between or something?
19 MR. McINTYRE:
No.
I would say there would be an 20 area that we would have to change the methodology.
We would 21 have to change the methodology in the way we do calculations.
22 They would have to do changes to their methodology on how they 23 do regulations.
Because right now there's enough things that 24 we look at.
25 MR. WARD:
So although you've drawn the curve there, Ileritage Reporting Corporation (20?.) 628-4888 O
t
+
121 1-you' don't really--
()
2' MR. McINTYRE:
I know what two of them look like.
I 3
-don't know what all fifty-five Westinghouse curves.look like.
4 MR. WARD:
Okay.
Instead of a curve, you'd put two-5' points in there.
Is that it?
6 MR. McINTYRE:
- Yes, f
7 MR. MICHELSON:
It's bounded by the others.
8 MR. McINTYRE:
Yeah.
Right now we.make the statement-
'9 that'we're bounded by this calculation.
And if you take that 10 out I don't know where the bound is.
So Westinghouse would 11 probably have to go through.and develop--you know, either 12 extend this code back down in this area or use no trump and
-13 extend it up into that area'and do'something to speed it up.
14 MR. WARD:
Well, you've done enough calculations to 15 know it's bounded though?
16 MR. McINTYRE:
Yes.
Right.
17 MR. WARD:
That's kind of subjective I guess.
Yeah.
18 MR. McINTYRE:
If you chop it off and you don't do 19 that calculation anymore, and I can count it, we'll go out and 20.
reoptimize certain parameters, accumulator set points, high 21 head safety and probably low head safety injection set points.
22 And that will change where that curve is.
And we won't know 23 those points then.
24 If you look at the small breaks, the ones less than 25 an eight-inch diameter hold, they are pretty much very flow Heritage Reporting Corporation (202) 528-4880 l
0' 122 i
I j"
l rates:or slow depressurization and it's pretty much mixture
(}
2
. levels moving up and down in a two phase froth in'the core in L
3 this case.
l 4
And this.is the one that's done using a no trump code
~
5 and it's the one I just. mentioned that we did the intermediate 1
6 breaks with.
7 In this case, for Westinghouse plants, the peak --
8 temperatures are on the order of 1100 to 1400. degrees.
They 9
tend to be not as sensitive to the peaking factor.
So if the 10 small breaks moves toward being the more limiting cases and 11 there would be I think some certain benefits to be gained from 12 increasing peaking factors there for plants.
13 So if you look at the safety injection system, that's 14 the way we do the calculations.
And we went back and we looked 15 at the safety injection system.
What does it do?
And the 16 object is obviously to cool the core.
And it has to cover from 17 the one-square inch right now to the double-ended cold leg 18 guillotine breaks.
19 And if you look at the high head for Westinghouse 20 plants, there's a high head safety injection system, a low head 21 safety injection system.
There' s also the accumulators on the 22 cold legs.
23 And the conclusion is that if you look at the ECCS 24 requirements, they are probably not going to change a whole 25 lot.
Because we didn't see anything that we could really take Heritage Reporting Corporation (202) 620-4000 0
1
123 1
out.'
If you look at the high head safety injection pumps, I
()
2 basically they are for small break LOCA.
And they have l
3 somewhere between two and four pumpe, depending on the plant i
4 size and the shut-off heads tend to be somewhere between 1400 5-and 1800 PSI.
6 And since these tend to be the smaller breaks, and 7
any changes to GDC4 is not going to have any effect on.those 8
breaks.
You're still going to have to do the calculation.
The 9
high head safety injection system is going to stay pretty much 10 the way it is today.
11 MR. MICHELSON:
Was this work ever documented in a W 12 cap or somewhere?
13 MR. McINTYRE:
No.
Which work?
14 MR. MICHELSON:
You said you did the calculations.
15 MR. McINTYRE:
Those calculations, yeah.
They were
{
16 in W Cap.
I think it was 8479.
It was the No Trump Report.
17 MR. MICHELSON:
Okay.
18 MR. McINTYRE:
It was approved I think about three 19 years ago.
20 MR. MICHELSON:
Yeah.
Thank you.
21 MR. McINTYRE:
The accumulators, we looked at those.
22 And even if they are not used for the large break LOCA, for the 23 larger small-break LOCAs, probably above the four-inch--the 24 four, six and eight-inch breaks, they do need the accumulators.
l j
25 The holes are a little bit too big to be handled by just the Heritage Reporting Corporation (202) 620-4000 0
124 1
1 high head safety injection system.
2 On.a Westinghouse plant, the accumulators tend to be 3
set at.600 PSI.
And the shut-off head of the low head safety 4
injection system is around 400 PSI.
So those are the breaks.
5 They are going to come down and they are going to need that 6
push of accumulator water to recovery the core.in what we call
'7 a timely manner.
8 And if you'll look at the intermediate breaks since' 9
they're even larger and they start to look more like a small I
10 break or more like a large break and you get a protty rapid 11 depletion of the reactor coolant system.
You are going to need 12 an accumulator in that case to refill the lower portion of the 13 core and also the downcomer.
14 The other thing about the accumulators is if you look j
15 at the PRA studies, it's really nice because they are passive, 16 they are there.
There's not a lot that's going to break on 17 them.
They are pumped up and they do help out the PRA studies.
l 18 And the risk calculations that are done.
19 MR. WARD:
So you don't think there'd be any change 20 in the design?
There wouldn't be anyway to optimize the design 21 of the accumulator for this somewhat different mission?
22 MR. McINTYRE:
Not in the present plants.
Probably 23 not in the present plants.
When we talk about the new plants 24 that we've designed, yeah, there is.
25 MR. WARD:
Oh, that's what I mean.
Heritage Reporting Corporation (202) fi20-4 0 0 0
L t
125 1
MR. McINTYRE:
Yeah, there is.
What we probably do
'(f 2
in these plants in maybe change the pressure set point.
L 3
,Probably reduce it so that they would not push it in quite as l;
l 4
fast and blow a little bit less of it-out the break.
5 MR. WARD:
Okay.
l
6 MR 'McINTYRE:
So we didn't see a change,Fagain to 7
the accumulators, but we may get some chance of doing a j
l 8
relaxation in the set points.
You may be able to have one out 9
of the--right now we have to throw one away for.the large 10 break.
You wouldn't have to-do that anymore because the break 11 wouldn't be that large anymore.
You might be able to run with 12 one of the accumulators out of service while you are working on 13 the check valves or doing something like that.
14 For the low head safety injection system, there could 15 probably be some changes there.
Only for some of the breaks 16 the flow rates could probably be reduced.
That would be I 17 think one benefit there.
If people are having trouble with 18 their pumps degrading over time, you could probably get by with 19 less flow.
20 MR. MICHELSON:
These statements are for the case if 21 you can push your design basis break to under a square foot, is 22 that roughly it?
23 MR. McINTYRE:
Yeah.
24 MR. MICHELSON:
Thank you.
25 MR. McINTYRE:
And having not done--
Heritage Reporting Corporation (202) 628-4800 0
t 126 1-MR. MICHELSOD:' -Have you,done any studies to see if L
it's.even. reasonable to push the large break LOCA down to--or i
2 3
the. design basis:LOCA down.to under a square foot?
4 MR. McINTYRE:
You mean actually looking.at the 5
critical crack size--no, we. haven't.
6 MR. MICHELSON:
What other things'can: fail besides 7
pipes and so'forth and,-you know, they.used to be bounded by, 0;, the pipe break.
Now, the pipe break.is not the binding 9
consideration, or bounding. consideration'rather.
So you have 10 to go back and look at other things that can fail at high 11 energy.
Man ways, bell bonnets, so forth.
12 MR. McINTYRE:
That's a good point..
13-MR. MICHELSON:- You haven't done that kind of. study?
14 MR. McINTYRE:
No, we haven't, no.
15' MR. MICHELSON:
Okay.
Thank you.
16 MR. McINTYRE:
The other thing that you have to be 17 careful about reducing, at least in the Westinghouse plant 18 designs, the low head safety injection is that there are also 19 the normal plant cool downs.
Das3: ally the RHR pump is the way 20 you get from operations, it's part of refueling.
21 And also if you look at the post LOCA.
These things 22 have to run basically forever, or least some sort of cooling 23 provided by these things. basically forever.
And if you look at l
24 the way they're sized, the flow rates and the heat exchangers 25 and the things'that go along with that, but what they are I
Heritage Ecporting Corporation (202) 620-4888 O
127 1
designed to do is to cool the plant down from hot standby to
/oJ 2
cold shutdown in X number of hours.
And that we think is
\\m/
3 probably the thing that would be limiting in this case.
Not so 4
much an ECCS calculation.
The flows could go up or down 15 or 5
20 percent.
I don't know how much of a help that would really 6
be to a utility.
7 But I think you would run into the cooldown 8
capabilities fairly quickly if you started reducing those 9
flows.
10 So if you are looking at a summary basis, the systems 11 that you've got in place today you still have to keep at least 12 for the existing plants.
What you might be able to do is you 13 get some changes in tech specs and because you are looking at 14 the smaller breaks, you wouldn't have a need to start the rT 15 diesel generator and bring it up to speed and load it in ten O
16 seconds.
And I think that that would be a help of my 17 understanding of the diesel generator problems.
18 If you look at just operational benefits from 19 increased peaking factor and this was the Westinghouse position 20 letter that was sent to the Commission, was that we feel that 21 we can get the same thing in peaking factors phase in 22 operational flexibility for the utilities by looking at some 23 large break space from the large break track calculations and 24 taking advantage of the best estimate models which is what 25 we' re doing right now.
1 Ileritage Reporting Corporation (202) 620-4000 r\\
l
(/
s
'r
'128
]
1 So reall'y in conclusion we're saying that the systems I].
2 that'we have today we really are still going to need pretty 3
much as they are.for the existing plants.
4 We looked at EQ and the containment designs, and 5
traditionally it's been a large break LOCA problem which has
(
6 set the design basis for both the pressure and the temperature.
)
7 What we've found is we get some small decreases in. temperature 8
you are still going to have to go back and also in the pressure j
9 for some plants.
For the Westinghouse plants it's very unique i
10 to each plant design.
We are finding, since we've made some 11 improvements to our massed energy models--these are 12 calculations that we take--we do the calculations usually to 13 the AE and they do the calculations on containment pressure--
14 that the steamlir.e break is starting to become more limiting, 15 not only in the temperature space but also in the pressure 16 space.
17 And we're still going to have to look at the 18 steamline break calculations.
If you look at a steamline. break 19 right now, surprisingly the wornt temperature case is.not the 20 double-ended break.
It's something on the order of a little 21 bit less than a square foot.
So even if you can do away with i
22 the double-ended break for the steamline,
.t's not going to be 23 a help.
You'd have to get that calculation down to something 24 less than a square foot.
And we haven't done that for carbon 25 and steel so we don't know what sort of a break size that we Heritage Reporting Corporation (202) C20-4000 O
O^'
l I
129 1
can expect.
If you don't get it down less than I think it's a
]
(f 2
square foot or nine tenths of a square foot, there's not going 3
to be a benefit to be gained.
I 4
It turns out actually for the temperature for the
,5
. calculations that we looked at for a Westinghouse plant, that 6
the double-ended gets.about a 70 degree lower containment 7
temperature than the one square foot case does.
8 And the other thing, we haven't done the calculations 9
to go back and look at sizes less than that to see the benefit, 10 but you're still going to put the same amount of mass and 11 energy into the containment as a function.
It's going to be 12 over a longer period of time.
But we' re not sure what the long 13 term effects of that for sure would be.
14 We made some estimates and if you'll look at what it "T
15 (J
-would do for getting rid of the large break LOCA, it's going to 16 have an effect beyond 300 seconds.
It's usually the first 300 4
17 seconds that's calculated as a limit of the steamline break.
18 And a typical peak again is about 340 degrees and that occurs j
19 around 100 seconds.
Beyond 10,000 seconds, when basically 20 everything is out of the reactor coolant system, the RWST is 21 emptied and everything, there's really not going to be any 22 change.
I mean you've got so much mass, so much energy, you've 23 just moved it from here and you've put it into containment.
24 MR. McINTYRE:
If you get rid of large break LOCA, we 25 think at 1000 seconds for the calculation that we did--again, Heritage Reporting Corporation (202) 628-4888
l J
130
)
1 just taking large break out and looking at the steamline break, e's
)
2 in this case for the limiting case, we saw about a 40 degree
%/
3 benefit in containment temperature at 1000 seconds, and if you 4
looked at an average between 300 and 10,000 seconds, on a time 5
average basis, it was like 18 degrees.
Again, this was going 6
down to what we thought the limiting steamline break would be 7
in this case, was the.9 square foot for this plant.
8 And I don't know what 40 degrees or 18 degrees is 9
going to be worth in EQ space, because the way people do the 10 calculations or the EQ testing right now, you know, it either 11 passes or it fails.
It's not qualified to 350 degrees or 330 12 degrees.
They don't give you "it's qualified to this."
It 13 made the curve or it didn't make the curve.
And so 14 I think what you'd get there is that people would basically
(~3 15 when they went through EQ testing in the future they could do LJ 16 it to a lower temperature but I wouldn't see an immediate 17 situation where if you had a transmitter up on the wall and you 18 found it wasn't making the temperature and you find out it was 19 going to be 18 degrees less, I don't know how you would turn 20 that into something that you could leave it up on the wall for l
21 another year.
22 And one thing you might get out of that would be an 23 extended qualified life or a qualified life of the component.
24 MR. WARD:
I don't know if you were here earlier--
25 MR. McINTYRE:
No.
IIeritage Reporting Corporation (202) 628-4888 O
_7_ -. _ _ _ _ _ - _ -
131 1
MR. WARD:
We heard from an engineer from a utility l
(*)
2 that there are a lot of sort of what.seems kind'of Byzantine l
3 relationships between, let's say, operating procedures and j
4' assumptions about large break LOCAs.
I 5
MR. McINTYRE:
Uh-huh.
6 MR., WARD:
And that in fact action points in s
7 emergency operating procedures might be key to some indicated l
l 8
process value, but that indicated process value'would have to j
i 9
have a correction made to it for uncertainty introduced in an 10
-instrument or a transmitter because of harsh environmental 11 conditions.
12 And so with assumptions about large break LOCA, one 13 might be forced to make emergency procedure actions at what 14 could be non-optimal process points.
)
15 Have you considered that sort of thing at all or--
16 MR. McINTYRE:
No.
17 So if you look at--now turning to the newer plant 18 designs, there's the APWR SP-90 which is our evolutionary 19 design.
And really it's pretty similar to a four-loop plan of 20 today.
It's got accumulator tanks.
It's got a high head 21 safety injection system and a low head safety injection system.
22 As I said, you are still going to need the high head 23 safety injection system.
You are probably still going to need l
24 the accumulators.
There might be some things you could do if l
25 you are going to be changing the sizes of breaks that you look I
Heritago Reporting Corporation
(
(202) 628-4800 l
()
l f
132 1
at to.
Optimize the high head safety injection system for this
()
2 plant.
Again, we haven't gone through the calculations.
You L3 know, we calculated the curve for the large break'and'small 4
break.
And in this plant, we did do the intermediate break 5
calculations to ensure that there wasn't something strange as 6
the result of the design that was going to get us in trouble, j
E 7
We did do a whole complete spectrum for this plant.
8 So for the SP-90 we didn't really see anything that 9
we would change.
We might go through some optimization studies
~
10 on set points, but we wouldn't see making some major changes.
11 If you look at the advance passive, the 600 megawatt 12 plant, this is a whole lot different unit.
It's a totally 13 passive safety injection system.
It's a core make-up tank and 14 accumulators, and it has a depressurization system in it.
And
[
it depressurizes into this containment RWST that it turns all 15 16 of the very small breaks into--I think it's an eight-inch 17 break.
18 So if you look at--actually it's on the next slide--
19 that the small break--actually the eight-inch break--becomes 20 what we consider to be the design basis transient in this case, 21 because everything sort of focuses and turns back into this 22 break.
23 If you could get rid of large break LOCA, we could 24 probably get rid of the accumulators on this plant, if we 25 didn't have to look at that.
That's basically what they're IIeritage Reporting Corporation (207.) 620-4000
133 1
there for.
The core make-up cank, basically what the design of lll 2
that is to flood the whole system for the larger breaks and 3
that would still be thero, but you probably wouldn't need the 4
accumulators in this case.
5 We haven't done any cort of calculations to see what 6
changes in steamline break would do in this case.
The passive 7
containment system would take care of the heat removal.
- And, 8
again, that's not going to change.
You've got so much mass, so 9
much energy.
You are just going to move it and put it out in 10 the containment.
11 So we wouldn't expect to see really any change 12 probably in the EQ curves as a function of this.
You know, a 13 large break would go away.
We've not sure what would happen on 14 a steamline break.
If it looks like the rest of the plants, ggg 15 you might see a 30 or 40 or a 50 degree change. But not 150 or 16 200 degree change.
17 So what it does for us, our conclusion was that we 18 can make some changes in like tech spec peaking factors.
We 19 could probably delay diesel generator start time.
You get some 20 reduction again in the environmental qualification envelope.
21 Now, again, I don't know what that's going to be worth.
Or how 22 you exactly put it in practice.
23 The big thing here io that a lot of the constraints 24 end up because you still have to look at small break LOCA and 25 we don't have a good way to make that go away.
We can develop IIeritage Reporting Corporation (202) 628-4880
134 1
a best-estimate model.
Right now Westinghouse plants are not
()
2 small break limited.
We've focused where the pain in'and it's 3
getting a peaking factors back up and addressing large break 4
If we did this, I'm sure we'd have to do as our friends 5
in the back of the room have done, and look at better small 6
break models.
7 Eliminating large break LOCA isn't going to change 8
for existing plants.
Really you need a safety system.
It 9
doesn't make them obsolete.
You can't take them out.
You are 10 not going to abandon anything in place.
11 Again, the point that I was making earlier was that 12 you probably have to do some new types of plant analyses than 13 we do today if we went to look at the intermediate breaks.
14 And this gave rise to our--we can get, for the 15 Westinghouse plants, usually that's where we onded up, we can
(}
16 get the same operating margins from using our best estimate 17 LOCA model.
Right now we've gone from peaking factors of 18 around 2.3 of peaking factors of somewhere between 2.5 and 2.6 19 with clad temperatures of around 1800 to 1900 degrees.
20 So we put our efforts into our analysis methodologies 21 in this case.
And we got operationally we think to almost the 22 same place.
And we have another calculation to see what it 23 would do for us for steamline break.
But this is looking at it 24 just purely from a vendor standpoint, the things that we have h
25 control over, the things that would impact us.
And we didn't Heritage Reporting Corporation (202) 628-4888
l
+
l.; ) :
'135-1 see'any major benefits that.we could have in plant:
2 simplification.
At least'from.this for the existing plants.
3 The one thing that'we might be d ie to do on the new l
l 4
pla'nts for the AP 600 is to take the accumulator tanks'out if 5-we didn't have the LOCA large break.
6
-MR. WARD:
Okay.
Let's see. Going back to'this.
I'm 7.
still worrying over the curve you-drew and the apparent need to
~
8
. develop a new code or do some sort of new analysis for the 9
intermediate breaks.
10 I mean if.there's so much uncertainty associated with
]
l 11 the status' office of intermediate breaks, how do you know right 1
12 now that there isn't a problem relative to what's calculated 13 for large breake?
14 MR. McINTYRE:
The large break--wait, I can't-15 remember the numbers when we did the calculation, but the small 16 break clad temperatures I think were around 1200 and 1300 17 degrees.
The intermediate break went down to like 1000, and 18 when you get to the large break, the answer is always 2200-or 19 very near 2100, 2200.
And you look at.the difference between 20 1000 or 1200 or 1300.
And the 2100, 2200, you calculate for a 21 large break.
And you compare that to the. types of numbers'you 22 get for the intermediate break, and one is so much larger than 23 the other one that it's okay.
It's assumed you don't have to I
24 go out and look at it and it's assume that there's not like a l
25 double hump in it.
Heritage Reporting Corporation (202) 628-4888
136 3
1 i
- And that's exactly the point when you start chopping 2
.off the.large break, at what point do'you cross the'line and when9do you'know that the intermediate break is not larger than
'3 4
'the small break?
And those are the extra calculations that 5
might have to be known.
6 MR. WARD:
All right.
Any questions for Brian?
7 All:right.
Thank you very much.
8 MR. KAMMERDEINER:
My name is Greg Kammerdeiner.- I 9
am with Duquesne Light Company, and I'm the Chairman of the 10 Westinghouse Owners'Grcup Material Subcommittee..
11 What I'm about to present is a summary of projects 12 that we have worked on or'are presently working on or are in 13 the discussion stage in the Westinghouse Owners Group.
j 14 And these projects, as it will become' apparent, i
. 15 you'll probably question what's the applicability to the 16 discussion today.
These projects all deal primarily with the 17 present scope of GDC-4.
The purpose of the presentation'is 18 basically to inform the ACRS of what we've worked on in regards 19 to leak before break in the Owners Grcup and possibly provide
~20 some insight that if the ruin was to be extended, that there i
21 may be some logical extension of these programs.
l 22 As the Owners Group, we deal with subjects that are 23 generic in nature, but also unique to a Westinghouse-designed 24 plant, so if the rule is extended beyond the containment, the 25 involvement of the Owners Group might be somewhat limited in Heritage Reporting Corporation (202) 620-4888 O
137 e
1 that Westinghouse plants' uniqueness of design is somewhat
()
2 limited to the NSSS system.
However,_there may be some 3.
concepts that we are approaching in the Owners Group that would 4
have a logical extension outside to other systems.
5 I quickly want to run through completed projects that 6
dealt with leak before break which was the effects of aging in 7
cast stainless steel and structural integrity, the objectives
,8 being to determine the degree which thermal aging affects the 9
structural integrity of cast stainless steel components other 10 than pipings and fittings, i.e.,
pump casings and valve bodies.
L 11 12 The results of this program we were able to 13 demonstrate leak before break to be feasible for Westinghouse-14 designed pump casings and valve bodies.
[
And the purpose of quickly going over that was the 15 16 lead in the project that we're presently working on, which is 17 the relief from pump casing ISI based upon leak before break t
18 methodology.
19 The objective of this program is to eliminate the ISI 20 requirements for reactor coolant pump casings of all 21 Westinghouse PWRs.
22 What we are doing is picking up where the previous 23 project left off.
Applying the leak before break methodology.
24 If the pump casings are all cast stainless steel, that leak L
25 before break has successfully demonstrated for primary loop 1
Heritage Reporting Corporation (202) G20-4800 0
h 138 L;
.1' piping, also cast stainless steel,.and that the thermal aging 2
. impact on leak before break would be previously addressed.
'3 We intend on utilizing the previous leak before break 4
in thermal aging work to support elimination of ISI of reactor 5-coolant pump casings.
And we're coupling the leak before break 6.
. methodology with ISI history to support the initial objective.
7 And by ISI history, the radiography that has been performed on 8
reactor coolant pump casings to date has not revealed any 9
degradation, i
10 As you are probably aware, that relief has been 11 granted to many utilities on the examination of pump casings l
12 based on this thought process.
j 13 Now, quickly to go over the work involved with 14 performing a casing inspection could. require coniplete pump
{ }
15 disassembly, core off load, plus that the radiography 1
16 equipment, either the miniature linear accelerator or a cobalt 17 60 source severely limits other outage work.
18 The bottom line of reactor coolant pump casing ISI, 19 high radiation exposure and a very high expense.
i 20 The program end products, submittal requests for ASME 21 code revision to eliminate the ISI examination requirements.
1 22 And also, if necessary, plant specific leak before 1
23 break for relief request justification.
24 The benefits of this effort are estimated at thirty-i 1
25 five to a hundred man rem per inspection.
The economic I
i i
Heritage Reporting Corporation j
(202) 628-4888 i
()
1
'1 139 l'
' benefits 400'to 500 k per inspection.
And the' industry-wide i( ))
2
' savings estimated to be as high as 8000 man rem and $75 3~
million.
4 Again, this being directly related to GDC 4 as 5
presently written.
If there was an extension of the rule--the 6-potential' exists, and I'm not ready to explain or offer 7
explicit examples of where it could be applied, but the 8
potential is there to take similar methodology on other 9
systems; 10 Some sheets that are in.your handout, which I believe 11 are next, deal with the pressurizer surge line and I don't--
12 excuse me, I do have them.
They are just out of order.
13 This is another project that we're presently working 14 on.
The objective being to assess potential impact of surge
{ }
15 line stratification on plant design and operation.
To 16 recommend fixes and further research.
And assist Westinghouse 17 owners in responding to NRC Bulletin 8811, 18 Now, the leak before break implications with this 19 project are rather straightforward.
To demonstrate the 20 continued validity of leak before break while accounting for 21 surge line stratification loads.
22 Again, extension of the rule, the potential exists l
23 for similar work in other areas, on other systems.
l 24 Finally, an issue that we're just starting to look at l
25 is the reactor support structure embrittlement issue which you l
l l
Heritage Reporting Corporation (202) 628-4888
R f
140 1
are familiar,with the data from the-Hifer program suggested (f
2 that radiation-induced embrittlement could affect the service 3
' life of reactor vessel support materials.
4 The potential load sources used for determining 5
critical flaw side include and they are listed here and.you'll 6
see the large break LOCA is one of those.
7 Now, the potential for a leak before break for the 8
reactor vessel support embrittlement issue is use LBB to 9
eliminate'the large break LOCA consideration and thus reduce 10 the critical crack size.
11 The benefits justify operation of effected units for 12 the licensed life of the plants.
Mitigate need for ISI reactor 13 vessel support.
Support flen efforts, and with the end result 14 being ALARA benefits and naturally economic benefits.
15 Again, the issues that I've just gone over'are all s
16 presently within the scope of the GDC 4 rule.
And the purpose 17 of presenting this information was to show that if the rule was 18 extended, there is potential for similar efforts on other 19 systems.
20 While not being primarily an Owners Group issue, 21 there certainly could be efforts taken on by individual 22 utilities, at least in the Westinghouse-designed plants, for 23 similar or related isstud.
24 MR. WYLIE:
I take it then that the Owners Group has 25 not taken a position then on the extension of the leak before Heritage Reporting Corporation (202) G20-4000 0
141 1
break?
2 MR. KAMMERDEINER:
Not per se, no.
In the 3
Westinghouse plants, to be up front about it, there would 4
probably not be that many generic unique issues to a 5
Westinghouse-designed plant that the Owners Group would be 6
involved in, as a funded Owners Group project.
7 MR. WYLIE:
So basically you don't see a lot of 8
advantages for the extension?
9 MR. KAMMERDEINER:
I think the advantages are there 10 for the extension of the rule.
I'm just citing from the Owners 11 Group projects that we are involved in within the present scope 12 of the rule, there could be a logical extension of some of this-13 work provided the rule was extended to other systems.
14 MR. WYLIE:
But not for equipment qualification--
15 MR. McINTYRE:
None of these issues per se, no.
16 MR. WYLIE:
Basically you feel like the present broad 17 scope rules--this past position that present rules are adequate 18 to cover the areas.
19 MR. McINTYRE:
Again, I think there is potential if i
20 there were similar issues that came up in other systems and 21 leak before break was a possibility, that issues similar to 22 what I just discussed, you could apply leak before break to
'23 those.
To answer it in the same manc.er.
24 MR. WARD:
I guess, Greg, I'm a little--now, you are 25 really representing the Westinghouse Owners Group from--you l
Heritage Reportir7 Corporation (202) 620-4998 O
i
l 142 I
said the Materials Subcommittee.
Is that right?
2 MR. KAMMERDEINER:
I'm here representing the 3
Westinghouse Owners Group.
I happen to be Chairman of 4
Materials Subcommittee.
5 MR. WARD:
Okay.
But the incentives that we've heard 6
mentioned and discussed, conjectured about I guess earlier 7
today, have not been in the materials area but have been in 8
other areas.
9 MR. KAMMERDEINER:
Right.
10 MR. WARD:
That's why I'm a little confused how you 11 are answering Mr. Wylie.
I mean do you think there are 12 incentives of this sort for Westinghouse plants or is there 13 just so much variety that nobody's really looked hard at it 14 yet?
15 MR. KAMMERDEINER:
I think there are incentives to 16 handle similar related issues to what we worked on within the 17 present scope of GDC 4 in a Westinghouse plant.
All I'm saying 18 is it may not be handled as an Owners Group effort due to the 19 non-uniqueness of design.
But certainly as an owner, I think 20 there's a benefit there.
l 21 MR. WARD:
So you think from the owners' perspective 22 there is sense in extending the rule or not?
23 MR. KAMMERDEINER:
Maybe I can clarify it with an 24 example.
25 MR. WARD:
Okay.
I l
Heritage Reporting Corporation (202) 628-4888
143 1
MR. KAMMERDEINER:
I would feel that a good benefit f( )
2 would be to influence the required examinations, ISI
~
3 examinations, if leak. before break could be used as supporting 4
justification for that.
And with the example--now, naturally 5
the dollar savings that we're citing for a reactor coolant pump 6
casing certainly and probably would not be that order of 7
magnitude in other systems, but the potential could be there.
8 MR. WARD:
Okay.
Any other questions for Mr.
9 Kammerdeiner?-
l-10 Okay.
Let's see.
Mr. Siegal, you wanted to say 11 another word or two.
12 MR. SIEGAL:
I wanted to summarize a few of my 13 earlier comments.
I've heard a lot of discussion today.
Some
.14 of it seemed to get a little bit unfocused, and I think there's
{}
a very sharply focused message that I would like to state 15 16 before we leave today. And it's a fairly brief message I think.
17 One of the things we have found at Combustion 18 Engineering and with the CEOG is that the issue of leak before 19 break, which for years has been a fraction mechanics type of 20 issue and discussed in terms of pipe whip restraints, is really 21 an issue that's much much broader than that.
And that while 22 we' ve made a lot of progress in the past nineteen years, as 23 Dave Ayers said, in leak before break technology, the more we 24 talk about it, the more we find out that in its broader 25 implications, it can have a significant benefit on plant Heritage Reporting Corporation (202) 628-4888
i 144
'l safety, a positive benefit that hasn't yet been taken advantage (n,).
2 of by the industry.
4 3
In fact, the more we look at it, I guess I would l
4 almost put it in a reverse phraseology.
It strikes me from all 5
the discussions we've had back at Combustion Engineering with j
6 our systems analysts, our equipment experts, our ECCS experts, I
7 that some of the assumptions about large break LOCAs that our 8
plants have been designed around have an overall negative 9
impact on the safety of a plant.
10 Now, that's really the message that I think we wanted 11 to come with today.
Not that we want to enhance safety by 12 doing something different.
But to my mind what we want to do 13 is remove something that for years has really had a negative' 14 impact on safety.
15 MR. CATTON:
Could you give us an example of that?
{}
16 MR. SIEGAL:
I am going to give an example.
17 In our slides today we talked about three major 18 issues of the plant.
One is containment buildings.
One is EQ 19 of equipment.
And the other is ECCS.
20 I'm a structural engineer so I'm going to use the one l
21 I'm most familiar with and that would be containment building 22 integrity.
23 Now, it turns out from some ot che studies that have 24 been done in the industry in ASME Section 11 and in Life 25 Extension Studies that probably the single largest degradation Heritage Reporting Corporation (202) G20-4000
l' 145
'l mechanism on containment structure integrity is the periodic
()
2 testing to accident pressure of containment structures.
Jmd 3
the fatigue occurs at some of the sharp discontinuities, some 4
of the penetration areas, and also some concern about l
5 containment cracking.
l l
6 Now, studies have shown that the method'of failure is 7
fatigue.
So it's a cumulative effect in that from a fatigue.
8 degradation point of view,.the frequent testing at that higher 9
pressure-is the single most important loading for the continued 10 degradation of containment.
11 Now, one of the things I'm involved with in Section 12 11 is the life extension studies, and, of course, from the 13 life extension studies, fatigue becomes much more'important 14 because you are not only concerned with part of your life, but-15 you are concerned with extended life if people desire that to 16 be an option.
17 The point is, and I hope it's a simple message, is 18 that we believe after all the teork we've done that leak before 19 break is really a true technology.
It's reliable.
It means 20 something.
And if it means something, and if we were to take j
21 advantage of it to predict lower containment pressures, Land 22 therefore reduce the test pressure for containment structures, 23 we would have, in fact, removed--actually we would have 24 mitigated one of the more damaging loads being applied to a 25 present structure.
l Heritage Reporting Corporation (202) 628-4000 O
l
- _ ---_--_ A
(
146
'l Now, that's what I meant a few minutes ago when I (f
2 said that what we really have is perhaps some negative impacts 3
on safety that we'd like to remove.
Because we would enhance 4
future safety of the structure, increase its future structural 5
integrity, by lessening the loading on it.
6 Similar arguments have been made--
7 MR. MICHELSON:
Excuse me.
What kind of life 8
enhancement are you thinking of that you would gain?
9 MR. SIEGAL:
Well, when people talk about life 10 extension or life enhancement, the industry has a hard time 11 deciding how many years they are talking about.
Some people 12 whose studies are--
13 MR. MICHELSON:
Well, I'm just trying to get a feel 14 for how important this particular fatigue-is in terms of the 15 useful life of the containment.
How much are we reducing the 16 useful life by each cycle?
17 MR. SIEGAL:
Okay.
I can't give you that number.
18 MR. MICHELSON:
You know, it might be infinitesimal.
19 It might be trivial.
20 MR. SIEGAL:
I can't give you--
l 21 MR. MICHELSON:
Indeed, it does reduce the life a 22 little bit.
l 23 MR. SIEGAL:
I cannot give you that number today, but j
24 I can respond by saying that at the Section 11 meetings where 25 the subject is addressed by containment experts, it is I
1 I
Heritage Reporting Corporation (202) 628-4888
()
l
147 1
considered a non-trivial item.
It's considered a significant lll 2
item and some people have expressed concerns about it.
3 The problem we have is that the industry has a hard 4
time coming to grips with it because we seem to be caught in a 5
situation where we're looking in mirrors.
We want to do one 6
thing and the regulations seem to indicate another and I guess 7
that's one of the messages we wanted to talk about today.
8 Now, you've asked for hard facts and you've just 9
asked another question saying what is the number per cycle.
10 And I agree that that's the right question to ask.
And I admit 11 I did not come here today with that purpose in mind, to answer 12 those types of hard questions, even though I agree that they 13 have to be answered.
14 The message that I wanted to give is that there are 15 two basic limitations that I understand right now that prevents 16 us from taking advantage of leak before break technology in a 17 way that would improve plant safety.
18 Now, we also believe that there are significant cost 19 benefits to the industry.
Significant reductions in man rem 20 exposure.
Significant simplifications in how plants operate.
21 And I'm just going to talk for a minute about the safety 22 because I think that's really the highest priority item.
23 And the two issues that I think are preventing us 24 from going forward, one is the perception.
And the perception 25 is that the staff has not shown a willingness to broaden the IIeritage Reporting Corporation (202) 628-4888 O
148 1
1 l'
issue to these other applications.
Now, I don't know if that's
- J2 true or not, but I do know the fact that the perception is 3'
true.
Whether there really is that sort of attitude or not, I 4
really don't know if that's true or not.
5 The second point is what is the status of the present l
6
~ rule?
Now, as I said earlier, I am a structural engineer not a 7
licensing engineer.
But my understanding of the present rule
)
8 is that it would not permit me to recalculate pressures and try 9
to use the rule in its present form to justify a lower 10 containment test pressure.
And therefore the rule may need 11 some changing to allow us to do that.
12 And so the message I'd like to give and it's a brief 13 one I hope, is that the more we talk about leak before break, 14 the more the benefits seem to permeate almost every aspect of a 15 plant design.
The containment structure is a nice one because 16 it's a simple message.
17 As you heard earlier with some of the presentations,
'18 when you get into emergency operating procedures, instrument 19 error, 'the larger gets a little bit harder to explain in simple 20 terms because it's so built into the design basis of a plant.
j 21 But they are there.
They are just a little bit harder to l
22 explain neatly.
23 And so I guess the message I would like to leave with 24 is, and it's the one we came here to say, is we have a 25 perception that the door is closing on how this technology Heritago Reporting Corporation (202) 628-4000 0
L l
-149 l
1 might be applied, and we would like very much to see--to not j
. ( l}
l 2
have the door closed, but just the opposite.
Because we think 3
there are some significant safety benefits that the industry 4
can see if there's some encouragement to do that.
5 Some of the people have said today that they feel l
6 that they don't want to commit the resources into an uncertain 7
regulatory area because they don't know where it's going to 8
lead them.
9 And I guess that's really where we are at 10 loggerheads, is how do you break the circle?
And that's the 11 message I would like to leave you with is that we think it 12 would be beneficial to the industry to break the circle, allow 13 the analyses to be done, and come back with the hard facts, 14 knowing that if the hard facts support it, we can then make
[ }
15 progress.
16 Thank you.
17 MR. WARD:
Thank you very much, Mr. Siegal.
18 Anybody else have anything they'd like to ask?
Any 19 questions for Mr. Siegal?
20 We can go off the record now for Executive Session.
21 (Whereupon, the open proceedings were concluded at 22 4:55 p.m.)
23 24 25 Heritage Reporting Corporation (202) 628-4888
7 l
r.
1 CERTIFICATE 1:)
l 2
3
.This is to certify that the attached proceedings before the 4
United States Nuclear Regulatory Commission in the matter 5
of:
ADVISORY COMMITTEE CN REACTOR SAFEGUARDS 6
.Name:
THERMAL HYDRAULIC PHENOMENA SUBCOMMITTEE MEETING 7'
8 Docket Number:
9 Place:
Bethesda, Maryland 10 Date:
March 7, 1989 11 were held as herein appears, and that this is the original 12 transcript thereof for the file of the United States Nuclear
-13 Regulatory Commission taken stenographically by me and, 14 thereafter reduced to typewriting by me or under the
(}
15 direction of the court reporting company, and that the 16 transcript is a true and accurate record of the foregoing 17 proceedings.
18
/a/
\\
t5 d$,d/
19 (Signature typed) :
IRWIN L. COFF NBERRY 20 Official Reporter 21 Heritage Reporting Corporation 22 23 24 25 Heritage Reporting Corporation (202) 628-4888
o S
1 8
N 0
O H
E C
I T
E R
AY TA A
CG TN E
IL O
E S
I P
L M M E
P O M
R O
AN O
G N
NY H
C E
L I
A C B
H K
R R
R A
E O E
U P
9 OE T
N T S
O 8
N T NA C
9 S CI L
IT K
I A
SL 1
O E GU I
DE R
U BRNG DR CA7 E
E I
R o
F DH Y OR F
E E YC T
E U NE O
T A
B P OL TF L
M E
N E
H A
O C
I DS U
E B
T M R
I I
M E
K WR VN I
E DF TA GH L
N T O
AE T
ITN E
S F
E O C
Y O
E I
F C
M F
IL O
O P
o
o 9
4 N
R S G
-C N
OCT E
N B D R OI I
E D TI D
A D F O G M
H E NT N E A L E O S
T S Y O S N U
C O TI E A H N O H
E F E MC H T
I H
O YO O
H D TMFN I
D I
L C
L NR TWO OI E I
I B F BTAO D N M
C O N D
N E E E UOI UA G
T MN E GCMO P NNI Y
P A
R A
I I
I
,N M
,M D D M B I
4O 4I S D N
OL YD R
- L E E M E D L B NE I
R E
U F U MT UNP D
G NP G D T S D AE N
D OH T B T A E P T A P O I
E CC I
MN E A HE OI OWU A R
O E S L
C T
T o
T E
TL E H M SWNK D NL DD E A NDR NAP C E
E E
,P MDI ME T E E U E
AU I
I MWT M7 H
A VE R A
E R
NL U N9 O R
T R UE R I
T E L R E 1 R E N B AQ R I
I D
M A M
,SWT E
E O CS E
I A
R 2 C 6
C E E E E ROE I
E 8 P E
EY RV TQBE SM Y
P 9 P R F N E U OSE I
N F
FE RE K
G O1 OE A C Q
OE R O
CB N
E P UD AI O
C BI N
P QN SO CI A R
E S S 1 L
S TI T
AE A SDQ L
1 T
O D
L N
E L C S DCMGP F
,R GMU E I
P AOANE F 7 S
E T R F O O
NI C A8 DCINMO I
O P
I R
M P F O RNYI C T9NCSOHF A AE L BODP A S1 AE U CSOS I
H L
C o
o o
o
O S
ss R
o E
F F
S N
C T K A
D N A OT T I
N I
L N E E SS S
E B A M
U F
B CI E
ME N P
,O RE F E 8
G 8 R
O M T A
I 9 NU A
N OQ O OO TS F
NTC ST 1
IT E
O I
,T R E
N YOY I
I C6 A B
T E
GTC CE A O M
IL L K
I I
OI F C C L O L M A
RI N E
L OD O O I
S P D A L P NE P C E AO M P H C
MR G A C Y
.C N
I O
TOL ON E B 8 IL F
N O
A S
T 8
I
)
R O
D9 B
.T NDI U
U TE KE 1
N E
O RH NP T A T P
Q N E T E
2 M
C E S TD E E R M2 O I
TI
(
L ON MB S
D S
BP A E
R R I
Y GU N Y TE N E F S E P D L A G AR A B N
G O
R E A M
O SF T E
E I
L L N N O CL E
P T YB Q V OA C O AE I
O R M OC H
U TE N C
- E OL U
K N E L N
E I
D MNNR C L A D VA O
E ONU OE OE NNE V
R F CAF F T P L AODE H
C o
o O
l11ll\\}lili i
1!;
l ll l
1 I
l lll O
4 E
R Y
5 R
O G
0 E
D OD W
N L E L
S E
OT A
SN V
N R R
E HO T
R E E ZS,SL HC P K U TI N R E TE P E
T A
TI O OU T U E N E CI DF D
S R L
T N E K B
A I
E L E R S A S S
T TAV A OE RE K T
N A O E
E MI C S L P R E R O N
E V P B TOO R
S C P L S U O
- T F T M
M E E E O
AN N S R L BR M
C
,N RO T E
A KT S
O E OS EF H E
P D TE AT O
C I
TB G I
VT G E E U N E
- EL L I
E I
I C
TL R OA L K I
C T R
A F E I
,GS TE ON L
E U S P
NL Q O
F B
F P L U E
E N U
E MUA O MF O
M G
NS Y I
MY C O A O
- D S NR SP L N I
YE N OT E SCX OO TV VNCE NI E RS L AE HI T I
N E ZI U E P E CS E CI V D T
WEI N WXOHE O N
o o
O lllll
>l1l1!
O A
E 4B T
R O
D S
,O N
T F E
U N E D Y O
G E B N G I
S U
M-A O O
A GK P L R
DA XO N
EN RNI U E OO J
L H
GC CI N T
F NE
/
O S
C O
T T
N E F
I S
OT N F N OK E E A O I
.S A
B E
L EC I
R R
NO E
HI L OE HOR N T
P F R T SA O N P I
O WAHI P
)
O I
DF R
S E E TYS
,A t
o TB E G L BI S
n RN U M
N D I
c C K UL EM R
E I
(
A TA FD O E D S
S E PEOA C C N T
NL UD M
N E
T O
R Y
E O X N
S F TTSH CE E
AO ER L T T I
M E
P OI N E E RN P P B I
EO S H M
O E A MT E T L
O AT YRL E H
I I
C PA R
E T3 TE C
RORA8 T
ICI E UANT9 F A C
L N
R SGUS1 OD P
I K
I I
L RP E E L B
P AW N A AE U
O V R
N P
o NI B O
j
I m
O s
L D
E s
A E E G R
o T
S RN E
N E
U DUA T YD S EME NSH S E FI Y
I AOCR MSS L
T NR P
O D AI T L
N OA TX T T U A
I E
R E DA O R
R N E N MI B R
N S
YE E
E P V B E
E I
NL MNM A
BN U E E OP L T GT I
E RNY TG A
B Q
FCI UI O AE L I
S T
E E HOA AQT L M EE K
S L
E N E TINI RR I
L RNP D E
B SA NT L EA A AO E ATT C HI R RNO T OT UNS I
T R
E P OMN E
I D
TSAS S U T
N OY L
SI E
E E L L E TE L S E EO IF L L P L
R M
L EEV L R E
P S
,F E L H I
I O
T E AE E UI WNTS P
P S
F H R
,DU U
Q N
OT M L R
I I
I E
Q S
E O
E Q P
YE TTD SEE D
E E F O F
ME V T F NI I
S H R I
E E F
RI I
OEW I
E E T
S O L T F R
E NMI H H N
I EF EE T T IF GF H RA T T E E NL T OS N EN BI S S
,E I
AE T TS CNI
,M EG I
F T
E TN N N U V E T I
L ED CN E C S NIL E E A R B U CN
.UL EO M MC I
N E
E E
R E E R E A T
GR BR I
B S
A E
R UK S
,H E IUT YV E
E C S
S OR NN R
Y R
S E E R EOAI E T NQN RE E EOTS T
A P L
V E E
H E XI E GWC E E
RCS F
T R EF GN L
D ONARTI WI H US SG BE DS C
A NROHOUH O
BH N E I
S W N
O
~
O A
)
A E
5 L
B O
U R
E E
L B
H E YE F U
B T A A
HAHO R
L I
R TMT E
H E T Y
S B
H T TC HD E T I
U DI I
T B
T WR P NI L D
L C
AASI I
B F
R E
N R
T A
E CTO GL,U E W D
C N
NNC WAOI E
N E E L
I E
E T RP N
U MO I
B R
I E T V N OP D
E E
A A
E P C T
X A S S T E Y
L E UO D E T
S T
E H
P C O P I
E I
E R ST F
U M
N I
O A
S R
RU VYN Q
E L F
I I
S R
E A
O E
R N O S P
GGS R
M P O E E
(
NE N E E Q
V OI R H
S P
O E E ST T US T
HR E
N E O G I
S OS E L G
TAE AY N
T U R E N
CS E
N I
I VTI NSD E SO P A SE S K OTE BC I
T M C E DE A Z
I E
I I
F F
E D
VM D E L TI I
H P
B F NE E NANC E
X T M E
AOI L T E E E E D
U A BR MP G
E F E SS O R C
N X
O R S T N S I
IDYE I
E R
TBAN E E R
I R
TI V
E E RC O
N E
E G S
E OIO F
I J
F TN B E
N R
HRR A SAOOB U
I H
P TP P M ASNCL I
E CS H
S AU TI o
o O
o E
R D
G R
E N
I U
U E
E I
Q R
D R
S L
D T
L R
E C
U U
E E
I R
C L
N A~ -
H U
I A
C Q
F E
M E
L C
T E
E N
I C
R T
M S
B N
E C
M N
E F
O S
O I
E T
C E
R E
D O
N E
E T
L S
I A
I I
Y L
C D
U A
U Y
S D
M W
U E
Q L
O T
M E
A L
I I
L S
R T
S E
E U
C C
O E
E O
R R
T L
S L
I U
F B
R T
E S
T R
G B
N B
I C
N A
A A
E W
G O
C E
E O
T N
P I
R L
A P
C T
C I
I S
Y O
T L
T E
I T
C T
O S
E R
S N
E T
D N
E A
D P
T E
R R
E I
T N
L E
S F
E T
E E
R E
C A
A V
E E
T D
E W
R U
G E
B E
R N
E R
H E
R S
O T
O O
T R
T L
E P
I P
M P
A E
L H
B S
E T
M A
U F
U N
H G
E W
T S
S S
N D
F R
B Y
E T
R O
T I
N O
I I
E o
I T
S E
F V
A E
H C
M T
F O
K B
M R
T P
T N
O N
I I
S A
C B
T E
R C
P I
W U
R E
T S
G L
S O
E I
F F
M N
N U
G E
N P
N Q
N N
R S
E E
G D
R E
O T
I I
D R
N E
T D
W S
D H
T E
O H
P E
I R
Y V
R W
I i
T E
L N
E F
C W
I A
B O
P D
T O
Y I
I T
F M
C G
S C
D S
R H
C E
T E
G E
N R
D A
N T
I R
E D
R E
E N
E W
A O
E S
T V
I I
D O
T A
R S
X M
E O
T T
H R
R I
T A
L S
A S
T A
O E
E I
L S
D S
V L
R N
E E
T S
E T
N T
E O
K E
U R
R D
G E
I I
I F
C N
U E
S R
F B
F S
E Y
E E
E E
T N
S D
O I
N T
L N
N E
U G
M B
P E
G A
T I
L E
O H
Q O
U H
N L
R E
A E
R B
L I
S D
R T
B O
W T
E I
S D.
L G
R E
I S
R U
E S
N Y
R Y
T L
O O
P N
A T
P S
T C
S O
E I
E E
H E
T E
T E
A C
D F
C P
L B
T G
I I
N F
E N
F P
A H
E A
M E
S T
M S
M o
I o
ll
O G
AS N
,S B
S E
O I
K T S A MI E E O ML I
PSL DL E R R GE T L
E ONI ADE YGNS HF I
G K
AS I
DAOT E
I I
HE ET M NV F
,WP O
H O
D SORE LI E L SH T
E L E NI NT T
I R L HGWE W
N UA T
GI TF E
SSXO ML P E HE I
D E E UB DH K
I E
E L S R
IF T E DL T O
I I
I O
T RV E U EE L H
)
t B
TOF BGL S N
n E
E o
M ACO AE R
L L
c E
N KS A U
UL TA D
(
S SUU CE E S
O L V R E
OF S S E
S C ITR P
E E E H H T C AP E RI F
E R H L CT T I
I DR E TABNI AO L
M E WD E
E NO R T L RSE U E
T C
AOAS L SZ I
F N R B
D A MF S
R U E
T E
S
.AL E C R S
S YC S
AC U
H T S
T L I
T E
E P
E H I
F S
R T_
WIL UF RCP AE SR o
O t
l!
~O ST E
Y D
V F E L R
E G L
E I
OE KL NS I
A E H U T
I NT R S
R R T AP Y H
E U A DS E P F O U
L AI T BMW TE D E
S C
R N U SD,E A L
A I
G E N B U E I
P E
N E.F R 2 D P L A N L QR S U E
UL A
N A N H N F 0 T
I U R S
UM
,ET A
I S B A
N E NP A F L T R S
T B C
STA E F TS E E E T L A C
H L
E HC HS R P U I
F B
GC R C T T E H T P OO ARCA S R TO CB E W UE E
TSA N E D
O E E I
I O
E DWE A E N H E
E N E
H L
H E
H TXR B
R T
B E E TTH A
R L T E OAI Y
E A
H A
T S F
DT E E QR ON N E
E E
,E HR E E N
U O N L
F R
S TN T R D A T ASCA S
C P A
P T N O
S I
I R
E ). CR NU S
S E E NTD N E
E S
XML O L
CG OU I
E V E E B BU O L
KT I
E E
L A BO C U XN ACSE S
R (E DE AI I
E L L
YP N E WD DR E S
.L H U U
DMIAL G A S SABR R N
T R R
AI T U CR L NI A E L O E TTR T
CWC G S S
R E A Y E K R E L R
I RL TS N C C
L Y
A E CP F
E L E F A
E E E
SRCP R O I
F HL UE OE AAE ACWE TAF B T R (
T I
HE E
I CH H
AT T
o o
O
O
)
A 7
t B
n O
oc
(
E S
G R
E E
U Z
NL TTE I
S U
NP BS I
SE U U
B A E MR L
OL D B
I F
TPNS E E E E E W DR CP N
E E
E R P I
L E
N L A U
I B
B P
U OW P S O SE A
Y AT E N D R N
T S
SE G
O E
S I
U M U
.N F
DI S
KE O P
A E
R AR E D O S
E I
E UN L
E R QA E E
E V
B V
- E T N S
E E R N E
E L
R AS D H
T R
E NN L
I C
B AI R D G
S ME E
N C KRHE D AOTHN IVC E F TE E
E L RR P
E OF X I
F HE P F OE I
CH AT o
O ll l
3
.. c,.
o a
c.
e i
PIPE BREAK PARAMETRIC STUDY W.C. HORAK R.J. KEllNETT O
BROOKHAVEN NATIONAL LABORATORY I
MARCH 7, 1989 i
BROOKHAVEN NATIONAL LABORATORY l}l)l ASSOCIATED UNIVERSITIES, INC.(I til
f.
I I
l O
L ii DVDLV.LEM PilRPOSE:
TO DETERMINE THE EFFECT OF BREAK OPENING TIME.0N PEAK CLAD TEMPERATURE AND CONTAINMENT PRESSURE AND TEMPERATURE FOR Q
INTERMEDIATE TO LARGE BREAKS l
BROOKHAVEN NAll0NAL LABORATORY l)l)l Q
ASSOCIATED UNIVERSITIES, INC. (1 til l
O c
PROCEDURES:
(
USED 4 LOOP STANDARD PROBLEM PWR DECK FOR RELAP-5/ MOD-2 CYCLE 36 (ISPRA) WITH CONTAINMENT DESCRIPTION FOR MILLSTONE-3 FROM CONTEMPT 4/ MOD 6 DECK l
BREAK SIZES:
2 x 100%
2 x 50%
O 2 x 20%
2 x 10%
BREAK TIME:
INSTANTANEOUS 0.ls i
1 0s 10.0s 50.s t
l 1
BROOKHAVEN NATIONAL LABORATORY l}lyl l
O ASSOCIATED UNIVERSITIES, INC.(llli
l l
o l inu O
0_
n ba ro o
ta i
t re c
n e
e j
G n
m i
O 0
y a
1 nS e
t t
e S
fa OX tne m
n ia t
OE no C
iOO i
m e
o ts e
y Oo S
i y
no r
i t
a c
i e
'o o
m j
h n
re i
E iz y
ru t
i s
e s
r f
e F
P a
r S
P R
oy W
ro ta r
P e
n eG ma o e
tS o
O
~
!Og j
bg L
E SSEV m
r n
e r
O OC O r
ed g,l O
f r
ep e u r
Cu eu pa r
gn n1 n
o o o
We w
e p
e T
e UH Ol ol C
LP LP uP re su ms r
s e
o a lu c
m o
n n
o n
y A
wB c
o n
le D
w t
o n
D i
OO O
i
CONTAINMENT' DESCRIPTION-
~ '
8 8
VOLUME =
2.25 x 10 FT -
2 FLOW 11,000 FT STRUCTURES 2
AREA (FT )-
1 STAINLESS STEEL LINED 7228.
CONCRETE 2
C0flCRETE 144,555 3
STAINLESS STEEL 18,770 4
CARBON STEEL 379,943 1
5 CARBON STEEL LINED 22,325 1
CONCRETE i
6 EMBEDDED CARBON STEEL 11,000 LINFD C0llCRETE 7
CARBON STEEL LINED 65,679 CONCRETE EXPOSED l
" " ^ ' " ^
HIIN TO AMBIEllT' TEMPERATURE O
A5500ATED UNIVERSITIES, INC.(I Ll b i
= _
j I
l!
ll 1
a
~
O e
m c c c c c cc e e e e e ee iT s
s s ss s s 0
0 91 1 U
- 5. 6 7 5
- 7. 4 0 1 80 564 P
02 1
C 571 2 924 5631 453 X
n I
o R
ccc ccc c
i t
eee eee a
e T
sss sss s
r 1 400 650 A
u D
2460 246 O
1 M
N k
U ae r
R B 1 e
r 0
u l
s=
i u
a F
o e*
n y
e m b
o e0 ni000 i
t s0 00 0 aT052 d
a a1521 t
1 e
t sk a
lu Cxxxx n a xxx n
i I
m e2222 nr222 e
m s
r iS a
oB e
T B
N nu R
O i
llllll l
o em c cc ccc e ee eee iT s ss sss U
9 68 785 8.9 6 702
)
P 2 52 953 C
1 62 366 t
853 552 noc n
(
o ccc ccc i
t eee eee a
sss sss X
ru 050 050 I
oR D
346 546 TA
- k M
ae 0
rB 0 0
N 1
1 s-
=
u U
n o e e*
o e m m
R ni000 i000 i
t aT052 T052 a
t 1
1 sk k
lu n a xxx a xxx I
m nr222 r222 e
e iS oB B
i N
T o
l
_ e e
m c cc e ee T
s ss i
1 63 U
- 9. 0 4
)
P 406 C
378 t
564 noc no
(
cc c
i t
ee a
e ss X
r s
90 u
1 D
760 I
eR 1
TA
- k M
ae0 rB05 e
N r
s u
u=
U l
i n
o e*
a F
R o
e m ni000 y
i t
aT052 b
a t
1 sk d
lu n a xxx e
I t
m nr222 e
an iS oB i
m N
re T
e 1
O Es gme oo,:$$
9 o -m ll 11 11 ll ll o
<.m
-?
Ea vsu) c) o e in "o
a
$O oe E8 3
go e
E Eo F
.n e-
- U
.C x g
_g eN CO O
i
-9 o
2 S
S 8
R 9
l.
(VISd) eJnsseJd i
O g
O
- 0. 0 0.1 0.0 0 00115 e
= ==
ru oo a *=
ta rep me Tc e is m
r a eC h
s%
p
==
0 o0 m1 o
t x A
2 tne mn ia tno C
~
1 0
0 0
0 0
0 0
0 5
0 5
0 5
0 5
4 3
3 2
2 1
1 gE Eeg2 E
O
p si 4
l I
O i
i i
--E3 I
gas oO C!"o. o 6 d o
s-m 11 11 ll 11 ll oo4.=
w
~
a w
O OM
-8 Oh o
E P *o e
i "O 9 1:
O 6x
-a N
.M M
n O
Cl.
C
-9 ef C
f 7--
O 6
6 4
6 6
6 8
8 8
8 8
8 8
8 a
e s
x e
(d) eJn1BJedwel O
l O
1 l
--E3 BC R
o o I
0"od6 0 o :
to
-Q 11 11 11 11 ll O O 4 ea
-8 9
-R l
2mMG e us o
i gu g
m I
n e io.
- o
- C00 E
Em s
f O
.c x o
e
- eq C
i O
O
-8 j
l
.g
-R o
8 8
?
8 R
R o
(VlSd) eJnsssJd i
O.
O lInU 0kG 0
1 0
0.1 0.000
,0 00115 9
e
= = =
ru ooA
- r t
,0 a
8 rep m
,0 7
eT ce
,0 is 8
re a
)c h C es p
(
s%
,0 5
e o0 m
m5 T
O t x 0
A2
,4 tne
,0 3
mn ia
,0 t
2 no C
,0 1
1 0
0 0
0 0
0 0
0 0
0 5
0 5
0 5
0 5
4 3
3 2
2 1
1
~
S yEo E@
O
O o25 e
O O C"O O'
O OO&em
-8 11 ll 11 ll ll O O 4 e5 2
-g i
a e
CU'O (D cn
-8 Q.U 8
co E$8
-s i O
E DD p
O Sx
\\
U at---?
g 3
d CD
\\
(D
_o" D.
11
.. O
-e 6
4 4
4 4
4 8
8 8
8 8
8 8
8 8
g e
e s
u e
=
=
(d) eJntsJedws.t O
i 1
I,
.g E3 9
g.e5 O. n o Od oo+
to 11 11 Il 11 ll
-g O O 4 e 3
-2 2
-R amMe O u)
-g bb 3
m
.s o $
C o
oo me E
EN s
O
.c x mm wCO O
-8
.g
-9
-o S
S S
8 R
R (VISd) eJnsseJd O
o 0
010.000 00115
= = =
e aoa* =
ru ta rep meT ce is a
rea h C ps%
o0 m2 o
t x A2 tne mn ia tno C
l 0
0 0
0 0
0 0
0 0
5 0
5 0
5 0
5 4
3 3
2 2
1 1
E 2 6egfi o
i 1
1 0
4
= =
$8E oQ odo35I@
II 11 Il ll ll
-2 oo<..
-2 i
O w
_ o.
r 3
Il
+.*
e8
.o 0U T
CD E
If i
- 2*
ii,
_=o*
O VW O
_o<
N M
1 CD n
G)
.. o L
(9 I
i
_O
, i
_o 4
i i
i i
i i
o o
o o
6 k
h m
(-1) 8;nis;edwej, O
t PEAK PEAK PEAK
('#
T CLAD' CONTAIN-CONTAIN-TEMPERA-MENT MENT TEM-TURE TIME PRESSURE TIME PERATURE TIME BASE CASE
("F)
.(1)_
(PISA)
(S)
(F')
LS)__
2x100%
1,511 7.7 50.7 20.9 288 20.9 2x501' 1,594 5.1 50.4 36.9 278 33.6 2x20%
659 11 43.5 60 252 37 6 T=0 1 2x100%
1 538 3.3 51.6 25.7 284 23.4 2x50%
1,,484 5.0 tis.7 39.5 275 37.3 2x20%
642 1.?
4/. 3 60.0 253 39 9 T=10 2x.00%
1,545 3.8 51.3 24.9 284 23.2.
2x50%
1,479 5.2 50.5 35.6 279 33.6 2x20%
637 1.2 44 0 60.0 253 40.7
)k 1,302 6.3 51.5 27.2 285 26.3.
2x50%
643 4.3 50.8 39.3 280 36 9 2x20%.
651 61 42 9 60.0 251 49 3 T=50.0 2x100%
642 6.5 50.9 42.8 281 42.8 2x50%
628 7.1 49.1 60 2 272 57.8 2X20%
616 10.3 44.8 98.8 249 78.1 BROOKHAVEN NATIONAL LABORATORY l} g}l
/]~~
A5500ATED UNIVERSITIES, INC.(llli
l
-(
1 1
0 1
SUMMARY
I A SERIES OF PIPE BREAK TRANSIENTS HAS BEEH SIMULATED USING RELAPS/ MOD 2 FOR Tile SAME BREAK FLOW AREA, THE PEAK VALUES OF THE CONTAINMENT TEMPERATURE O
AHo eRESSiiRe oO nor vary SioniFiCAN1ty WITH BREAK OPENING TIME.
l 1
l l
BROOKHAVEN NATIONAL LABORATORY l} gj j Q
A5500ATED UNIVERSITIES, INC.(llll
O P
U O
R F
G O
S S
Y R
G R
T E
N C
I N
I A
L K
W R
I A
O E
E B
E E
H A
R G
N T
C B
N I
I I
D G
O L
E R
N N
T P
R E
A E
N P
O O
E N
O A
F N
N O
E I
O I
E B
G I
T H
N T
A T
K E
S T
A U
N G
E N
B E
N L
O M
S I
I O
E D
T C
R N
S P
E U
T B
X M
E O
C f
O
O
\\
78 3
9
/
1 T
6 C
N R
I V
3 I
N I
P R
T C
P U
O A
S O
F R
R R
K A
G 7
A E
S 8
E Y
A 9
R O
0 1
B 9
T 8
S 1
A R
E D
R M
E R
R E
O FE D
B O
E V
I T
E M
F V
O R
RS T
E E
O R
P AY A
V B
P SS U
O R
P D
S L
N K
O A
E EL A
A F
PCCL V
D E
S OR A
E E
L B
LNO T
O I
B A
E TR E
T P
L VENO R
I O
D EHIF E
M O
N E
DT W
B L
I T
DD U)
A YYEE S
SS N
D U
GBTZ T
S I
E L
O AI N
TE A
V A
LDRD A
RR M
L V
OEOR L
OG O
E DVPA P)
PO G
V OORD S
ER O
N S
HRON GR RP E
I A
TPCA OE C
W EPNT EH LN
/
N MAIS CT AI E
E E
O C(
C E
D R
I B
R EY P -
T E
HB O
S S
V T
TW A
A OD E
P H
O P
GI L
A LO EE C
P A(
CR o
o o
o O
/
l' 1l J
am O
SD OH W
T O
E H
S M
S IS D
S Y
E E
L
}
L N
A D
I I
N S
J A
L A
E
/
T P
g E
E B
I J
D L
B P
(
B L
S D
I N
T N
N X
N I
C O
A E
I E
I L
S F
T D
F E
K F
A E
C C
E U
I R
N A
L F
E E
R C
A I
L O
D C
I V
L L
I M
E P
A F
E A
M M
N G
N Y
I SS O
R Y
T S
S C
A D
R OE L
E F
TC R
F P
O C
O F
O O
SU F
O R
S NS N
P N
O S
Y O
O ID E
T I
L S
TE S
I T
A I
AU A
L A
I R
CN B
I U
R A
II B
L E
P LT A
A T
M PN T
V A
O PO S
E M
C AC o
o o
o o
(
O 1
)
O N
N I
A A
Y M
A L
E T
I S
T I
4 R
M A
V E
I I
T R
R T
I E
P C
3 R
D O
A C
I R
N S
P B
G B
N P
B Y
B O
A L
L C
Y R
N L
T O
Y O
A S
I F
F T
M V
S S
I S
I S
I G
T K
T N
N C
A A
O L
I A
E S
S S
R R
A M
O B
B O
E S
B T
R T
N L
E A
O N
E H
H P
E I
N T
T S
O C
T I
I O
L W
D Y
T L
E L
N L
E C
E T
E I
GW R
R N
S U
RO N
G E
E G
UL AES R
SF D
TE P
D E
SAR E
ND T
ADP T
GE N
HI A
YI E
DG N
F SE CN0 I
NI ET RAE M
OA PD L
HR I
AN S
HP HE G
O D
0B EO EN EB CL CU CL o
o o
(
O
I!!
I o
O STL US ER BBL N
F O
O IT S
A N
Z O
S I
I D
R O
T A
U A
O S
C L
S I
E L
N R
P W
P P
T 0
A N
)
T E
M N
T M
O E
N E
L M
E G
B T
R P
N R
R I
I L
A U
H P
A P
C W
M N
M I
R O
E E
C P
T T
B I
E N
U P
J I
S o
0 o
o O
1 l
i
O D
EL I
S F
T T
O N
S N
R E
T E
P M
L M
E U
P E
R S
I R
I E
U U
U R
Q T
Q E
A E
B R
R B
F E
L O
P M
M E
F N
E T
O O
T S
I Y
S T
D S
N A
N O
C A
G O
I I
N T
F E
I A
I R
L C
L U
O I
A S
O L
U S
C P
Q E
P R
E A
L P
R A
O E
T T
C R
N N
U E
E Y
T M
4 C
t U
N N
l F
O I
E R
A G
I T
R V
N E
N O
M E
C E
o o
o O
F
M g.
)
O 1
g g
O
)
d
[
G 0
g
!"8 i
l E
~
a m
m ge m
g l
s e
5 "3
e
= m
o 5
PM S
E g
=-
ma m
a m
a 5
E 5
O dg t
ae W
W s
5 5
g R
da W
8 o*
E e
W
==
v 8
E WW 5
Se m
5 8
e" 5
mmggE QS 8
"E 5
~t
$9 2
s SM bb a
==
a 3e
=
m g
d Wr
=
W a
wE g
z 8
gf a
ii
=
mm e
e me m
bd 5
5 bE b
ow a
o a=
o o
o o
o o
]
t O
o
O O
c o
d
[
8 m
n
\\
z m
g E
d i
g i
-8
=
S d
c s
ifl d
u, 5
E a
e B
_a 8
5 mg8
=
E B
~
O
~
$gg E
EE g
8 i
e e
aa m
m W
g g&
E
=
m m
s E
E W
S a
- 5 E
E g
M M
C in 3
W 8
5 5
m 2
O O
O O
O d
T O
ERUSSERP T
/
N E
E M
RUT I
A A
E R
T R
E N
M P
O Y
M C
T E
I T
F R
Y R
O P
T G
T I
WG E
N S
R TS E
N NT M
O ET II I
F I
T N
GE A
R c
I E
NN T
O A
F IE N
P P
T I
DB O
N L
L C
N J
E IL O
M E
UA E
X U
O BI V
E I
I G
T I
U D
A I
TN T
G N
T T
NE A
I E
NTA ET V
T P
OSF MP O
R A
P CO E
F A
CD I
S E
D E
A N
ERD EDS T
O VUE CEA N
TCU AUR C
Y AUD HDC L
LRE NEN R
UTR EERI E
MS N
V U
I O
CG L
E N
EL EI -
M -
CI CD O
UF UL T
DO DI T
ER EU O
o o
o f
O
- i
O SR T
O N
R E
R M
E P
I S
N U
L O
Q A
I E
V T
R A
F E
T OS T
N T
N T
E NI I
R M
OF O
U E
IE E
T F
Y R
ER TN C
N F
T T
MU AE N
E E
I S
IS CB A
M L
N TO I
N E
G I
I NP FL E
C N
B WX IA T
A I
A E
OE O
LI N
L N
E N
V D
AT I
P N
G I
I MY UN A
E A
N G
T MET QE M
R L
A R
A ERE T
/
P H
A V
TT - F LO D
E C
M R
SSNA AP E
C T
R E
OYAS T
R N
R E
G S
CSM N
I A
A T
N N
E E
U N
P N
I O
EEEC 4#
Q E
I T
C CCCN E
T E
A UUUA l0 R
N R
T R
Y DDDH R
I A
R E
L EEEN I
E A
P A
P R
ERRRE V
Z M
S P
O E
N N
I V
I E
D N
Y E
E O
L R
E F
S S
A H
I A
A E
M -
D T
L E
E C
O N
G P
R R
U T
A N
M C
C D
T T
E I
N N
E O
S L
S I
I R
B o
o o
o o
o o
F O
O B
we
>g O
l
$a
[
5 2
^
- d N
l
^
s
=a a-e am
~E E
i W
$p
$5 h5 Bm g
e a-em
=
g=me= m
-M mE C
8m r=
gs a
OE"5 =sM ms v
m m
a O
3d 88 8
E
~
mgMg==9, gg Es a
sg n<s
,g g
g ea em z
mm m
a es ets8 ME*s 2
e amgmbOO d=
-W
=w 5
mdmd s
gs vaus"--
EE-a a2 B== t55
=
=
-mm=mmm m
nmm a
W 5
=
n mi ii gii iiii E
E 5
0 8
m m
O O
O O
O
g PLANT EQUIPMENT /0PERATIONAL FLEXIBILITY POTENTIAL BENEFITS o
REDUCED REQUIREMENTS IN LOCA ANALYSIS NUMBER OF SITS OPERABLE SIT VOLUME - PRESSURE REQUIREMENTS REDUCE LPSI PUMP REQUIREMENTS -
INCREASE LPSI PUMP / SYSTEM OPERATING MARGIN o
REDUCED CONTAINMENT BUILDING COOLING CAPACITY REDUCED NUMBER OF CONTAINMENT SPRAY (CS) PUMPS / COOLERS OPERABLE INCREASED CS SYSTEM / COOLER SYSTEM l
MARGIN o
INCREASE MARGIN TO SAFETY SYSTEM ACTUATION SAFETY INJECTION SYSTEM EMERGENCY FEEDWATER ACTUATION o
RELAXATION OF TECHNICAL SPECIFICATION REQUIREMENTS NUMBER OF PUMPS, COOLERS, ETC.
ULTIMATE HEAT SINK / FULL POWER OPERATION o
BOTTOM LINE INCREASE OPERATIONAL MARGINS MINIMIZE CHALLENGES TO SAFETY SYSTEMS MINIMIZE POWER REDUCTION / FORCED OUTAGES ENHANCES PLANT OPERABILITY AND FLEXIBILITY ENHANCES SAFETY lo C CE2 A l
3e O r O
[.
.N m
a g
e o
Q 5
a wmG
==e o
R mg=
l-M 8
5 we Q
E 1
O Y
A
.