ML19344A451

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LER 80-029/03L-0:on 800711,during Plant Startup,Core Spray Pumps & Diesel Generators Started,Due to High Drywell Pressure Sensor Actuation.Caused by Instrument Setpoint Shift.Plant Shut Down & Sensors Recalibr
ML19344A451
Person / Time
Site: Oyster Creek
Issue date: 08/11/1980
From: Ross D
JERSEY CENTRAL POWER & LIGHT CO.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19344A450 List:
References
LER-80-029-03L, LER-80-29-3L, NUDOCS 8008200365
Download: ML19344A451 (3)
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l e t :1 f On July 11, 1980, during a plant startup, the Hich Drywell Pressure I io,3, l Sensor RV46B actuated causing the core spray pumps and both diesel cen-  !

19 . i ; erators to start. After verifying that an actual high drywell cressure I i3isi ; condition did not exist, the primary core spray cumps were turned off. I i: i.! e This caused the alternate cumos to start and these were also stceeed- 1

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l i i o l l The initiating cause of the occurrence is attributed to ins +mmant ta*. I 1

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Jersey Central Power & Ught Company

, . Mactson Avenue at Punen Sc*l Acad Vcmstown. New Jersey 07960 (201)455-8200 CYSTER CREEK SUCEAR GENEPATEG STATICN Fcrked River, New Jersey 08731 Licensee Deent Pepert ae;cre No. 50-219/80-29/3L Pe:crt Date

, _ _ _ August 11, 1980 Date of occurrence July 11, 1980 Identificaticn of Orerrence Cperaden in a degraded rede pe=dtted by a limiting conditien for cpentien when the aut:ratic and rer:cte manual ind.atien features of two of the core spray pu:ps was defeated.

Utis event is censidered to be a reportable occurrerce as defined in the Itchnical Specificaticns, paragraph 6.9.2.b(2) .

Ccnditiens Prior to occurre.-ce

?.e plant was being restarted f-hw a refaeling/ main +anance cutage.

Plant parameters at the tire of occurrerce were:

Pcwr Cere: 67.5 >He Electrical: O SMe 4

Flcw Pacirculaticn: 5.2 x '0 3 gpn Feedwater: 3 x 10 lb/hr Rx Level 70" Rx Pressure 940 psig Rx Terp. 537.4*F 3 l Stack Gas 5.7 x 10 ;.ci/sec.

Descriptien of Cccurrence Cn Friday, July 11, 1980, at app d mately 1525 rcurs, while conducting a plant shutdown, the High Crywell Pressure Senscr RV46B actuated causing the core spray pu:ps and teth diesel generators to start. After veri.?f ing that an actual high drywell pressure condi+% did ret exist, the prirary core spray pu:ps w re turned off. This caused the al*a . ate pu:ps to start and these were also stepped. Ubder these ceniitiens the altermte core spray pumps wculd have been prevented f:tm starting aut:ratically.

Je sey Cen:ral Pcwer & L:gnt Cer cary s a ver cer et me Gereral %:ic Ut: ices Sys:em

Peportable Occurrence Ib. 50-219/80-29/3L Page 2 August 11, 1980 Apoarent Cause of Occurrence h occurrence was initiated by tra actuatien of High Drywell Pressure Sensor W46B at a pr?.ssure more conservative than tM regaired setpoint. 'Ihis led to tra operator stcpping the primary and alternate core spray punps. Due to the design of tra logic circuit, tra alternate are spray punps were prevented frcra starting autcmaticany until the trip sigrals cleared allowing the breakers to be reset.

Analysis of Occurrence

'Ihe core spray system provides an alternate supply of cxsollrq water to the reactor following a postulated pipe break accident in the reactor primary system. We core spray system consists of two independent locps. Each locp has a primary and alternate core spray pump and core spray booster pmp which pump water from the tcrus into the reactor vessel through isolation valves and a spray sparger. Both core spray systes win start autanatically upon receipt of a trip signal frcra any one (1) of four (4) drywell pressure sensors or four (4) reactor law level sensors. When the reactor pressure decreases to 285 psig tra parallel isolation valves open to anow flow to the reactor. Should eitMr of the primary core spray pumps fall to start, the alternate pump in that system

, win receive a start signal within 10 seconds of the initial sigral.

h safety significance of the event is considered minimal since the primary core spray pmps wculd have started autcmatici11y if another high drywen pressure or low reactor water level trip signcl was received. Also, the alternate core spray pumps could have t:een started manuany, if required, by locally resetting their breakers.

Corrective Action Immediate corrective acticn was to verify tPat an actual High Dryw_ll Pressure condition did not exist. t.e core spray pumps and diesel gerarators were than stepped. At 1605 hcurs a plant shutdown was ccrmenced. Subsequently, tra Core Spray System Instmxentation Channel alihration and Test was performed for sensor W46B then reperformed for all sensors.

h surveillancS tests revealed the following data:

Pressure Switch Desired Setpoint As Found As Ieft Desicnaticn W46B 1 2 psig 1.19psig 1.93 W46A < 2 psig 1.55 1.98 RV46B 7 2 psig 1.91 1.91 W46C 7 2 psig 1.2 1.95 W46D 52psig 1.45 1.91 Failure Data ITT Barten abdel 288A

.5 - 9.5 psig adjustable range

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