ML20151C176
| ML20151C176 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 12/20/1973 |
| From: | Rone A JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| References | |
| AO-73-32, NUDOCS 8103040891 | |
| Download: ML20151C176 (3) | |
Text
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Prellminary Abnormal occurrence Report No. 73-32
SUBJECT:
Failure of the test spool valve for NSO4A to properly ree.et after 5% closure test whidt resulted in it condition which may have cai,thed the FGIV to close slower-thrin norTnal should an ' isolation signal have occurred during the test Interval.
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e This event is considered to be an abnorrnal occurrence as defined in the Technical Specifications, paragraph 1.150 Notification of this event, as required by the, Technical Specifications, para-graph 6.6.2.a, was rade to AEC P.egion I, Directorate of Regultitory Operntions, by telephone on %ursday, Dece dier 20,1975 at 0900, and by telecopier at 1500.
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SITUATION:
it h.ad besn observed on~ Deceidier 17 nnd 18 that HSIV NSO4A was
.apparently overtravelling durinh the daily 5% closure exercise, thereby causing pressure transients of 6 psig and 10 pF res-N.
poetively.
Analysis of the. problem indicated that r
I overtravel was a result of the improper resetting cf the test spool v41ve.
To explore this possibility, reactor'pwcr was ro-duced to 853 ftit (<.40i of rated power) so that further excuzino-
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- t. ion of the test spool valve. assechly could be conducted with reduced possibility of a reactor scr;un due.to Valve closure,
'and to reduce radiation levels in the work arcs.
THIS DOCUMENT CONTAINS POOR QUAUTY PAGES
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l Pre 11mii.ary Abnormal Occurrence f
Report flo. 73-32 k vececher 19, 1973 r
i The 5% valve closure test was redone with an instrument techni-I cian in local observance of the test, The sticking condition l
l bd apparently worsened, thereby catsing the161V to go approxi-mately 50% closed and then reopen in the normal manner. The technician concluded that the test valve was the cause of the
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1hus, a situation wns created whereby had the va..lve..
been required to isolato during the test interval (approximately-2-3 minutes) it is unlikely that it would have het the. required closure tiene of <10 seconds, sinco exhmut air from the tmder-side of the valve operator piston is required to pus through t
the test valve assorbly. BecauJsc of the malpositioned valve assembly, the er.haust air would have.bcen restricted, thereby-slowing the valve closure time.
g tipunk', removal tmd disassenbly of the test spool valvo, it was observed that foreign ruterial resenbling red powdct was found on imd between the spool and s1covo essembly, although it has o
not bocn conclusively determined that' this wits the cause of the V31Vc stickln2, 7he spool asserbly is being sent to a testing 2
lab for.further cyliluation.
l RomDI At. / t,TICth 3
l The test spool y ve asser11y for NSO4A wm replaced. 1he 5%
1 closure tost w.w. repeated satisfactorily,.as well to a full closurv titeing test (6.7 seconds).
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Prelitinary
~
Ahnut=31 Occurrence
- Report"po, '73 32 ;;cer.bor 19, 1973 s
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SAFET( SIfNJFICO!G:
haring-the 51, closure test, had an isolation signal boon intro-duced, the valve may not have closed in the required time. The conscquences of this cVent were minimized since the redundsnt i
valve NS03A would have provided isolation and closed 'in the re-quired tir.4, in the event of a reactor isolation. Furthemore,
the " slow closure condition" was only present for the length of tinee the 5% closure test was in })rogress (2 3 minuteij.
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