ML19322D227

Partial Transcript of ACRS 790416 Meeting.Pp 228-229

ML19322D227
Person / Time
Site:	Crane
Issue date:	04/16/1979
From:	Advisory Committee on Reactor Safeguards
To:
References
TASK-TF, TASK-TMR NUDOCS 8002100070
Download: ML19322D227 (2)

Text

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I failed in this case?

There was some' talk about demineralizers,<

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or something else coming out of, the rumor mill.

I'm not sure. !'

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j MR. MAC MILLAN:

I heard the same rumors you did.

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i I don't really know what happened as the initiating event in j

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j5 the loss of Leedwater.

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DR. SHEWMON:

Okay.

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InthehandoutthatTedescohadthismorning,hehad!

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• 0 a list of six feedwater transients.

The PORV was activated in l five of them.

It stuck open in three of those five.

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MR. MAC MILLAN:

Yes, sir.

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DR. SHEWMON:

That's not a batting record that 7

k 12 anybody outside of the Major Leagues would be very pleased

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And I wonder if you ceuld say -- I assume, since that's 1

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l on the top of the pressurizer, that it's someth'ag you people 9

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' 15 lspecify, if you don' t bu!.ld it.

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Could you tell ine something about how these are I

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17 ]I i-tested, and whether we can see any improvements down the road?

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It's nice to tell the operator, to train him to tell him that

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'd it always sticks open, but that doesn't quite seem like the t

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i way to whip it.

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MR. IRC MILLAN:

Let me respond to several of --

t N,22 l!. where I think your question is at.

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I think the implication Oas that three out of five

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ig.i we.had the valves stick.

That isn't really the right (f~

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fl statistic.

We've had somewhere -

and I don't have an exact j.

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o j jwb 229 number, but it's in the range of 150 events in the history of I

.I 2lf the B&W units which have caused the power-operated relief valve l'

3 Out of that 150, in 3 instances the valve has stuck to open.

for one reason or another.

That is not far from the

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kind of statistics that have been generated in the evaluation 6;

of reactor safety, about a.02 probability.

It seems.to be I

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right on target.

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Now there was some question this morning about i

whether all of these valves were the same valves, or whether 9

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' they were different suppliers.

11 The valve at Oconee and the valve at Three Mile 12 !

Island 2 are Dresser valves and are essentially equivalent, I3l identical valves.

The valve at Davis-Besse is a Crosby valve l

1'* "i of a different denign.

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valves are used extensively not only in the These i nuclear business, but in the fossil steam business, for i

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pressure relief, pressure control.

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