ML19209A544

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First Interim Deficiency Rept Re Diesel Generator Field Relay Coil K1 Failures.Coils Replaced & Generators Returned to Svc.Addl Corrective Actions Will Be Detailed in Subsequent Deficiency Rept
ML19209A544
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 09/26/1979
From:
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML19209A539 List:
References
NCR-15P, NUDOCS 7910040300
Download: ML19209A544 (1)


Text

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ENCLOSURE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2

, DIESEL GENERATOR FIELD RLLAY COIL (Kl) FAILURES NCR 15P 10 CFR 50.55(e)

FIRST INTERIM REPORT Description of Deficiency The ueficiency, which arises from the failure of the field relay coil, is that the diesel generator starts and comes up to speed, but has no generator output. It was discovered by operating employees during routine operations of the diesel generator units. The diesel generators have completed pre-operational testing.

Failure of the field relay maintains the field of the generator in an elec-trically shorted condition throughout the start sequence, and the generator is incapable of any voltage buildup or output. Therefore, loss of the K1 coil causes a part of the emergency onsite electrical capacity to be unavailable.

The cause of this deficiency is under investigation by TVA and Power Systems Division of Morris-Knudsen (the vendor who supplied the Sequoyah diesel generator units).

TVA has experienced failures of these field relay coils only at Sequoyah Nuclear Plant. The companion plant to Sequoyah, Watts Bar Nuclear Plant, is equipped with the same model relay. Investigation is continuing to determine whether or not the relay coils are the same at Watts Bar Nuclear Plant as they are at Sequoyah.

Corrective Actions The field relay coils that failed have been replaced with new field relay coils from the same manufacturer (ITE Gould). All diesel generators at Sequoyah Nuclear Plant which experienced failed field relay coils are back in service.

Additional corrective actions will be detailed in a subsequent report on this deficiency.

1090 244 7910040 3