ML19329B156

Ro:On 720925,two Pumps at Oyster Creek in Standby Liquid Control Sys Simultaneously Inoperable.Caused by Interlock in Starting Circuitry Preventing One Pump from Starting When Other Is racked-out.Operating Procedures Changed

ML19329B156
Person / Time
Site:	Davis Besse, Oyster Creek
Issue date:	10/06/1972
From:	Finfrock I JERSEY CENTRAL POWER & LIGHT CO.
To:
Shared Package
ML19329B145	List: ML19329B144 ML19329B155 ML19329B156
References
NUDOCS 8001300729
Download: ML19329B156 (2)

Text

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d N ^w Jersey Central Power (r& Light Cornpany W.

i MAOISON AVENWE AT PUNcN BOWL. MO Ao e MoR AISTOWN, N.J. 0794o e 333.stit

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October 6, 1972 ~

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epBLl]f ur.v4 q Mr. A. Giambusso g b W- N,.

Deputy Director for Reactor Projects .

[,',7/.0 Directorata of Licensing ,

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Cij United States Atomic Energy Comission

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si Washington, D. C. 20545 ,

Daar Mr. Cia =busso:

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Subject:

Oyster Creek Station Docket No. 50-219

. Inoperabia Standby Liquid Control Syste=

, h a purpose of this letter is to report to yo'u an incident that occurred at Oyster Creek on Septe=ber 26, 1972 in which it was discovered that the two pu=ps in the standby liquid control syste=

were inoperabia at the sa=a ti=a'. .

At 10:45 a.=.'on Septe=ber 25, 1972, the "A" standby liquid control pu=p was re=oved fro service for replace =ent of the pu=p packing. De pu=p was taken out of service using Technical Specification 3.2.C.3 as the basis. It states, "If one standby liquid control syste= pumping circuit becomes in-operable during the run code and specification 3.2.A is =et, \

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. the reactor =ay rs=ain in operation for a period not to exece '// 4

.savan days, provided the pu=p in the other circuit is de=en D #

strated daily to be operable". Specification 3.2.A is =et,p (,

"A" pump breaker was racked out and the pu=p ' g8 7 therefore, the secured in accordance with plant safety procedures, new r- O/ li~ ,j fp,.g*gi was not. co=placed by the end of the day shif t, and the "A" 6 f pump was left in an inoperable condition. At 4:20 a.=. on cgpi k/

Septe=ber 26,1972', the "3" liquid control syste= pu=p was to be run to comply with Technical Specification 3.2.C.3.

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t y gg When the operator depressed the start button, the pump did

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not start.

An interlock in the starting circuitry prevents two l standby liquid control pu=ps fro = being run si=ultaneously.

his interlock also prevents the "3" pu=p frc= starting when the "A" pu=p breaker is in the racked out position. ne interlock is cc= posed of a nor ally closed contact in the Oi starting circuit of each pump. This contact is operated fro = a relay in the opposite pu=p circuit. If the "A" standby liquid control pu=p is started either fro = the control roo= with tha key lock switch or locally from the .

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n The Toledo Edison Company The results of your review are requested within sixty days. This information should be provided with one signed original and thirty-nine additional copies. ,

Sincerely,

. aW

- A. Schwencer, Chief Pressurized Water Reactors Branch No. 4 Directorate of Licensing

Enclosures:

Licensee's reports on occurrences cc: Leslie Henry, Esquire j

]

O Fuller, Seney, Henry & Hodge 800 Owens-Illinois Building 405 Madison Avenue Toledo, Ohio 43604 Gerald Charnoff, Esquire

Shaw, Pittman, Potts, Trowbridge

,- and Madden 910 - 17th Street, N.W.

Washington, D.C. 20006 Donald H. Hauser, Esquire The Cleveland Electric Illuminating Company P.O. Box 5000, Room 610

! Cleveland, Ohio 44101 l

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Dr. Peter A. Morris  ;

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April 20, 1972 -

The logic circuit was restored by disconnecting the motor leads from the breaker and racking-in the breaker. At 9:20 a.m.

' on April 11, 1972, an operability check of Reactor Building Isolation was conducted and proved to be satisfactory. A caution tag was placed at the fan control switches in the Control Roo= to notify operators that if a supply fan breaker is racked-ou; the Reactor Building supply da=per isolation control logic is defeated unless a ju=per is installed in the breaker cabinet. A s1=11ar caution note is being stenciled locally on the supply fan breakars.

As noted in the FDSAR, the primary objective of the Secondary Contain=ent System is to minimize ground level release of airborne radioactive =aterials and to provide for controlled elevated release of the building at=osphere under accident conditions. The contain=ent

• syste=s, ?r1=ary and Secondary, provide the principle =echaniss for mitigation of accident consequences. The off-site accident consequences, howeyer, are relatively insensitive to the Reactor Building in-leakage

_s rate as long as the Standby Cas Trest = cat System can =aintain the building at a vacuum. In this particular instance, the supply and s,,, N) exhaust fans tripped, the exhaust dampers closed, and the Standby Cas Treatment System was initiated. With the above situation, the air supply to the building was not only via the various in-leakage paths but also, and no doubt pri=arily, via the Reactor Building supply dampers.

Any accident conditions postulated that require sedondary contain=ent in determining environmental releases would, under these conditions, have a second path permitting release of the Reactor Building air at approximately a 60-foot elevation.

.I.n order to prevent a reoccurrence of this ircident, a circuit design change will be i=ple=ented that will pea =it a Reactor Building supply fan breaker to be racked-out for =aintenance without defeating the Reactor Building supply da=per isolation logic. Until this design change can be.imple=ented, a standing order will be issued

- fastructing plant personnel in the appropriate practice to be followed to avoid defeating the Reactor Building supply da=per isolation logic.

1 Very truly yours, l

M . .d h*- /

'~' Ivan R. Finftock' Jr.

Manager, Nuclear Generating Stations

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IRF/pk Enclosuces cc: Mr. J. P. O'Reilly, Director Division of.Co=pliance, Region I 1

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• Mr. A. Giambussr

• Page II

. October 6, 1972 .

1. r push button station, a relay is picked up which opens the nor= ally closed contact in the "B" standby liquid control pu=p starting circuit which prevents this pu=p from operating with the "A" pump running. The reverse is true if the "B" pump is started. The problem developed when the breaker for the "A" pu=p was racked out. It disabled the pu=p and at the same time it physically removed the contact in the startir.g circuitry for the "3" pu=p which s1=ulated an open contact. This prevented the "3" puny from starting. -

As soon as the Shift Foreman was aware of the inoperability of both pumps, he started a nor=al shutdown of the plant. In the meantime, he received permission to clear the maintenance safety tags and rack the "A" pump breaker to its nor=al position. He

• then ran a successful operability check on the "B" pup.p. The load reduction was stopped and the plant returned to full load.

In order to prevent a recurrence of this event, operating procedures have been changed so that operability tests of redundant engineered safeguards syste= cc=penents will be made i= ediately following any action that requires one of the systems to be ,

inoperable for maintenance purposes.

We are enclosing forty copies of this letter.

Very truly yours. -

[O7 }. [l lf 4/ .

Ivan R. Finfro'ck, h.

, .Vice President ,

IRF/pk

• Enclosures l .

cc: Mr. J. P. 0.'Rei.11y, Director Directorate of Regulatory Operations, Region 1 .

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