ML19290A432

RO on 720926:A & B Liquid Control Sys Pumps Inoperable at Same Time.Caused by Interlock in Starting Circuitry Preventing Pump B from Starting When Pump a Breaker Is in Racked Out Position.Operating Procedures Changed

ML19290A432
Person / Time
Site:	Oyster Creek, Three Mile Island
Issue date:	10/06/1972
From:	Finfrock I JERSEY CENTRAL POWER & LIGHT CO.
To:
Shared Package
ML19290A429	List: ML19290A431 ML19290A432
References
NUDOCS 7911070614
Download: ML19290A432 (2)

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Jersey Central Power & Light Company 3/~ -

MADI5ON AVENUE AT PUNCH BOWL RO AO e MORRi$rQWN, N.J. 07960 e 539 6111 October 6, 1972 J gSLUjg.

ur.v.s g Mr. A. Gia=busso f> jf,"$ h,y Deputy Direc:or for Reactor Projects .

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United Sta:es A:c=1c Energy Cc==ission Washington, D. C. 20545 s [  :-)

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Dear Mr. Gia=busso:

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Subj ect: Oyster Creek Station

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. Docket No. 50-219

. Inoperable Standby Liquid Control Syste=

, Tie purpose of this letter is to report to yo'u an incident thet occursed at Oyster Creek on Sepec=ber 26, 1972 in which it was discovered tha: the two pu=ps in the standby liquid control syste vere inoperable at the same ti=e.

At 10:45 a.=.'on Sep:c=ber 25, 1972, the "A" standby liquid control pu=p was rc=oved frc= service fer replace =en: of the pu=p packing. The pu=p was taken out of service using Technical Specification 3.2.C.3 as the basis. It states, "If one standby liquid control sys c= pu= ping circuit becc=es in-operable during the run = ode and specifica:1on 3.2.A is =ct, \\

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the reactor =ay re=ain in operation for a period no: to excee'//\  %

seven days, provided the pump in the other circuit is de=en E-,?O v strated daily to be operable". Y therefore, the "A" pu=p breaker Specifica:icn 3.2.A was racked cc: and is =et,C,{

the pu=p - g'h, 7n secured in accordance with plan: safe:y procedures. The wdC was not. co=picted by the end of the day shif t, and the "A" 61 t'.D., 'h~f 6 ' " /$ 3*

pu=p was left in an inoperable ccndition. At 4:20 a.=. on i 4 Th'D U'7 ,

Septe=ber 26, 1972', the "3" liquid centrol syste= pu=p was c3 'qjf to be run to ec= ply with Technical Specification 3.2.C.3. /g , L ,/'~

did When the operator depressed the start button, the pu=$ 5 7 2 8 6 not start. 1 .

, An interlock in the star:ing circuitry prevents two standby liquid centrol pu=ps f ro being run si=ultanccusly.

This interleck also preven:s :he "3" pu=p frc= starting when the "A" pu=p breaker is in :he racked cut positien. 'n.e interlock is cc= posed of a nor= ally closed contac: in :he starting circuit of each pump. This centact is operated frc= a relay in the opposite pu=p circuit. If the "A" standby liquid centrol pu=p is s:arted.either frc= the control roo= with the key lock switch or locally frc= the

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Cetober 6, 1972 ,

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push but:en s:a:1ca, a relay is picked up which opens the nor: ally closed con:ac: in :he "3" standby liquid con:rol pump starting circuit which prevents this pu p frc: opera:ing vi:h the "A" pu=p running. The revarse is true if the "3" pump is s:arted. The probles developed when the breaker for :he "A" pu=p vas racked out. It disabled the pu p and a: the sa=e :1:e 1: physically re=oved the con:ac: in :he s:ar:ing circuitry fcr the "3" pu=p which simula:ed an opt con:act. This preven:ed the "3" pu=p .

fre: s:ar:ing.

As soon as the Shif: Fore:an was aware of the inoperability of both pu:ps, he star:ed a nor al shut.dcun of the plant. In *,he meantine, he received per=issica to clear the maintenance safe:/

tags and rack :he "A" pump breaker to its ner:al pcsi:icn. He then ran a successful cperabili:y check on :he "3" pu.p. The load redue:1cn was s:cpped and the plant re:urred to full lead.

In order to' prevent a recurrence of this event, operating procedures have been changed *so that operability tests cf redundan:

engineered saf puards sys:e= cc penents will be made 1::cdiately follewing any ac:ica : hat requires ene of the sys:c s to be inoperable for =ain:enance purposes. .

We are enclosing forty copies of this letter. ,

Very truly yours, fairn.v&h,x?1c/

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Ivan R. Finf ro~ck, J; .

Vice Presiden:

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Enclosures cc: Mr. J. P. O'Reilly, Director Direc: ora:e of Regulatory Opera: ions, Region 1

. 1557 '287

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