ML19347C820

Ao:On 730929,during Surveillance Test on Reactor High Pressure Isolation Condenser Initiation Switches,Contacts on Agastat Relay 6K12 Failed to Close within Preset Time Delay of 15-s.Cause Unknown.Relay 6K12 Replaced W/New Relay

ML19347C820
Person / Time
Site:	Oyster Creek
Issue date:	10/09/1973
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8103040925
Download: ML19347C820 (2)

Text

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United States Atomic Energy Commission Washington, D. C. 20545 %f

Dear Mr. Giambusso:

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Subject:

Oyster Creek Station Docket No. 50-219 Isolation Condenser Relay Failure The purpose of this letter is to report a failure of isciation con-denser initiation relay 6K12. This event is considered to be an abnormal occur-rence as defined in the Technical Specifications, paragraph 1.15.D. Notification of this event, as required by the Technical Specifications, paragraph 6.6.2.a. ,

was made to AEC Region I, Directorate of Regulatory Operations, by telephone on September 29, 1973, and by telecopier on October 1,1973.

While performing a routine surveillance test on the reactor high pres-sure - isolation condenser initiation switches, contacts on relay 6K12 failed to close within the preset time delay of 15 seconds after tripping the pressure switch and deenergizing the relay.

Details of the relay are:

Manufacturer: Agastat Model: 7022PDT (fime Delay)

Range: 5 to 50 seconds Coil: 120V DC Serial No.: 1712236 The cause of this failure remains unknown. The relay has been removed from the circuit and bench-tested and appears to function properly, even after re-peated operation.

Relay 6K12 was replaced with a new relay. A satisfactory surveillance test was conducted and the isolation condenser system then considered to be ope rable.

As detailed in Amendment 65 to the FDSAR, at 1 cast one of the isolation condensers is required to act as a means for heat removal during a postulated loss of coolant accident. Actuation of relay 6K12 can be by means of high reactor t/

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Mr. Giambusso October 9, 1973 pressure or low-low reactor water level. It is wired into the logic circuit such that tripping of the relay provides one-half of the initiation logic for

-both condensers, the other one-half being its redundant counterpart on the same instrument penetration. A second redundant instrument penetration also includes two pressure switches, contacts from which also will initiate both isolation condensers. The significance of this event then is the loss of redundancy pro-vided to initiate one-half of the signal for placing the isolation condenser system in service.

Before making any recommendation to prevent a reoccurrence of this event, the cause of the relay failure should be identified. The manufacturer will be requested to perform additional tests on the failed relay in an effort to determine the cause of failure. The results of this investigation will be used to determine what further action may be necessary.

Enclosed are forty (40) copies of this report.

Very truly yours, e

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e Donald A. Ross Manager, Nuclear Generating Stations DAR:cs Enclosures t cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region I 5

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