ML20084G121
| ML20084G121 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 09/30/1971 |
| From: | Finfrock I JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084G115 | List: |
| References | |
| 4302, NUDOCS 8304210486 | |
| Download: ML20084G121 (2) | |
Text
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,s Jersey Cont 11 Powt; & Lip;ht mpany i
M A DISoN AVEt4U E A T PUNCH HOWL RO AD e M ORRIS T oW rJ. p. J. C79G0 0 530-6111 M%,
September 30, 1971 M
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Dr. Ieter A. " rrin, Directer j7 e
Div nicn of.seactor Licencing 4rJ
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Unit"! States Atcaic 6.ercy Cornission
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,Dear D r.
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Subject:
Oy ter Creek Station Docket I:o. 50-219 Failure of Icolation Con'D ser Line Preak Protection The purpoce of this letter is to report to you the failure of Icolation Condenser NZOlB to icolate during surveillruice tecting of 2 t <
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Jencorn on Feptreber 3,1971.
-u..,i Each irolaticn condenser ic provided with redunclant conden-
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cate nn,1 stem line breat d/p censors, any one of which will initiate
.{ Z' condenner isolation upon a suctsined five-second d/p cignal correspond-p..,f.[
ing to FC.7 f3cv.
Gile performing the test to chec.k the,icolatien Y.M. /
condenst 1 v.;1c circuitr.y, ste e line break censor 1B05_B1 was trip.ned;
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but the time deley feature of relay 6K81 failed to function.
This pr: vented a closing signal from being applied to the condenner valves folleving the precerited five-second delay.
Following the repl4 cement of relay (t'8A vith one of a different manufacturer and dring the cubsequent checkout of the j '
icolation circuit, the time delay feature of relay 6K8B was alsc found to be inoperable.
Thuc, had the isolation condencer been l
called for <_nd a line break occurred, no automatic isolation would he.ve taken place.
Removal of the failed relays frca their mounting bracketc and subcequent disassembly of the units, required to pinpoint the cauce of failure, was not done due to the physical location of the
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relays being such that reveral other relays would have had to been diaconnected and temporarily noved out of the way.
This, coupled wit';- the unconfortable work position required, vould have increased the time required to return the condenser to service.
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H3171 Jeveral reaconc for the failures were previously postulated whea problems were experienced with similar relays in the circuitiy
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for Inolat. ion Condenner H",01A, nil of which verc the result of what I
appeared to be excecuive heat generated by a resister in series with the coil.
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9304210486 711101 PDR ADOCK 05000219
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Prior nurveill: nee 'ectin? h'tl ' n ale! problems auncciated wi t, the ty; o f re J a;; i~'"ilel in thu i. : n' iv: canaencer logie c
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t-ac n ai ;Teren'
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. e ce these reluya WJ' n';U Or
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.t 4 U.t inulation logic ci' 2un.
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a r.H ar; sube ' w ntly eeu'. red the 1
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.a. r n m.mu! l A have clo el aut - stu Oly.
Tni accident in ::
t'.e n t 20 to tt.e 1TT/1H for tresk ninec up to har Imen a,
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that u l;/., a,,1: cate:> that cia.i p;crocations will nct occur anu th't the ' cliolc *a Il mne t; the tbyro t J, ncc.un:J ng all of ihe re ctor JuM.','
rel ea:- ' 1 directly t.o the enviro:: cent withcut s
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c The pipt-rupture condition would not. hnvc been annunciated but 1L
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Operator Veuld have teen provided with roactor je.
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'- r er:s t o re con.n G un:
i n ti. ' vieluity of the iucJ ation conjencern ::nd ru:liation doac rates
".aJal icalstiu. of th co:.ienna t. could have been a t
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rece r]ichen; m if the ' nlves had been chut within sixty necends of thc tlne the rupture occurred, the losc of cc:>lant fro:" t.he cit a ferentiat ru,tture wcula have been less than that for a
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A i!It is r c cak.
R..i e
All of the time delay relcys initially installed in the inclation condenaer circuitry have been replace 1 vith those of a di f ferent manu ructurer.
The testing frequer:cy of t he isolation circui' ry han been inercased' from qu trterly to rr.onthly until cufficient confidence in gained on the new relays to veu' rant a ch :ve back tn ihe former freq'toney.
We are enclocing tver.ty-five copien of thic report.
Very truly yourc,
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- hl.'/'r!0!ll Ivan R. FirNock, J{.
Manager, !!uelear Generating Stations IRF/pk 1:nelocures cc: :ir.
.I. P. O'Reilly, Regional Director Elvicien of Compliance, Region 1
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