ML20084H822

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Ro:During Surveillance Test of Circuitry,Time Delay Relay Failed in Isolation Condenser Sys.Caused by Burned Piece of Insulation Blocking Expansion of Bellows.Relay Replaced
ML20084H822
Person / Time
Site: Oyster Creek
Issue date: 05/17/1971
From: Finfrock I
JERSEY CENTRAL POWER & LIGHT CO.
To: Morris P
US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084H824 List:
References
12976, 2404, NUDOCS 8305060003
Download: ML20084H822 (2)


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Jersey Cent.rul Po ver & Light Company M ADISoN AVENU E AT PUNCH OoWL Ro AD e MORRISToWN. N.J. 07360 e 539-611i May 17, 1971 l

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Dr. Peter A.

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United Stat a Accaic Energy Cc=miccion

Dear Dr. Morric:

Subject:

Cyster Creek Stat. ion -- Docket 50-219 Isolatica Condenser Sy: tem Time Delay Relay Failure The purpose of this letter is to report to you, as a matter of interest, the failure of a time delay relay that was discovered during a recent ::urveillance tect of the circuitry that would isolate one of the two redundant Isolation Condenser Systems at our Oycter Creek Station in the event of a condensate line pipe break in this system.

The time delay relay that failed is a part of two redundant circuits for each of the Isolation Ccndenser Systcas; and during this test, it was observed that the redundant circuit in the sycton with the failed relay functioned satisfactorily.

Tnus, single failure criteria van met.

At the ssme time, both of the two redundant similar circuits for the other Icelation Condenser Cysten vere satisfactorily tested.

These circuits have a five-second time delay in order to prevent elocure of Isolation Condenser Systen valves due to an initial flov surge when a cysten is automatically placed in cervice.

Following the test, the time delay portion of the relay was removed and dinassembled for incpection.

It was discovered that a cnall piece of insulation had burned, probably due to exccasive heat frca a resistor in seriec with the relay coil, and dropped off.

This piece of insulation lodged itcelf in such a position that the belleva actuator (JL ]l L.

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Dr. Peter A. Morris Page II May 17, 1971 could not oxpand and allev the relay to function after the precet time delay had expired.

rJ.ie ruiled time delay >as replaced with a similar relay of a uff 2 cent.:anur,.ctrer an'i tested satiaractorily.

Additional replazament.ala/: h we be :n ordered and will be in:talled upon their arrival at the station.

?aenty-fiva copica of this repcrt are attached.

Very truly yours,

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'Ivan P..

Finfreck, Jra' Manager,1:uclear Generating Stations pk Attach::enta

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