ML20084E239

AO 50-244/74-07:on 740426,during Surveillance Test PT-9,one Underfrequency Relay on 11A Bus Failed to Transmit Signal to Logic Racks When Fault Condition Simulated.Relay Replaced

ML20084E239
Person / Time
Site:	Ginna
Issue date:	04/26/1974
From:	Platt C ROCHESTER GAS & ELECTRIC CORP.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20084E228	List: ML20084E231 ML20084E239
References
AO-50-244-74-07, AO-50-244-74-7, NUDOCS 8304140463
Download: ML20084E239 (1)

Text

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'. f ROCHESTER GAS AND ELECTRIC CORPORATION

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Ginna Station "

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April 26, 1974 p. p.

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Mr. James P. O'Reilly, Director Directorate of Regulatory Operations Regica 1 U. S. Atomic Energy Commission , .

631 Park Avenue .

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Subject:

Abnormal Occurrence 74-7: Failure of Underfrequency Relay rYs{.yfM -

During Surveillance Test Ginna Station

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Docket 50-244 Lr.*;,j;{e, b /-

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Dear Mr. O'Reilly:

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a.%.o This is to confirm my conversation with Mr. Walter Baunack today to report Abnormal Occurrence 74-7 at Ginna Station. -_ EMQ

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During the morning of April 26, 1974, while conducting the routine E" * -

Monthly PT-9 Surveillance Test (Periodic Test - Undervoltage and Underf requencyProtection llA and 11B - 4160 volt Busses) one of the E

underfrequency relays on the 11A bus failed to transmit a signal to .

the logic racks when a fault condition was being simulated. This , J. cc failure defeated one of the two channels of redundancy provided for W4 :,N .?

, underfrequency protection of this bus. .

The faulty relay was replaced with a spare relay. The spare relay was tested satisfactorily and declared operable at 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on ihdk[$.]

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April 26, 1974.

hf; Very truly yours, qjW./'.h.:

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PDR ADOCK PDR S 97 Charles E. Platt 1 Superintendent

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Mr. G. J. Swarthout, RG&E 'ifVg j,r a