ML20084F080

Ro:On 720131,while Conducting Monthly Surveillance Test, Underfrequency Relay on 4160-kV Bus 11B Failed to Transmit Signal to Logic Racks.Caused by Faulty Capacitor.Spare Relay Installed & Tested Satisfactorily

ML20084F080
Person / Time
Site:	Ginna
Issue date:	02/07/1972
From:	Amish K ROCHESTER GAS & ELECTRIC CORP.
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084F071	List: ML20084F075 ML20084F080
References
NUDOCS 8304200048
Download: ML20084F080 (1)

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.l February 7,1972 Dr. Peter A. Morris, Director

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p U. S. Atomic Energy Commission ICU gb L2 Washington, D. C. 20545 0 ,'

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Subject:

Detection of faulty relay during surveillance te Q A ffg L R. E. Ginna Nuclear Power Plant Unit No. I Docket 50-244 @ " '

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Dear Dr. Morris:

On January 31, 1972 while conducting the routine monthly PT 5.2 Sur- '

veillance Test (Periodic Test - Undervoltage and Underfrequency Pro- '

tection) an underfrequency relay on the 4160 Kv bus No.11B failed to transmit a signal to the logic racks when a fault condition was being simulated. This failure defeated one of the two channels of redundancy provided for underirequency protection of this bus.

The Plant Operations Review Committee met immediately and approved the removal of the inoperative device (811/11B) from the drawout drawer and its replacement with a tested spare.

The test was then rerun in entiroty and completed successfully as it did on the prior monthly test 01 Decemi'er 28, 1971.

Examination of the removed rela, cis-losed a faulty capacitor which was m elaced . The unit then nerformed norma!!y under several tests and it was returned to stock.

Very truly yours ,

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