ML20117A598

Special Rept:On 921119,ability of Control Battery Racks to Withstand Seismic Event Could Not Be Confirmed & Batteries Declared Inoperable.Batteries Expected to Be Restored in TS Required Time

ML20117A598
Person / Time
Site:	Oconee
Issue date:	11/23/1992
From:	Hampton J DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9211300212
Download: ML20117A598 (1)

Text

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{h Ba l-t34 G0h37;isl22 fu u m o: S C . a 79 f'YK DUKEPOWER November 23, 1992 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555

Subject:

Oconee Puclear Station Docket Nos. 50-269,-270,-281 speciai keport, 1echnicat specification s.7.9 At 12:00 on November 19, 1992, the ability of the as-built configuration of the 2CA, 2CB, 3CA, and 3CB Instrument and Control battery racks to withstand a postulated seismic event could not be confirmed. Accordingly, these batteries were acciated inoperable, all three Oconee Units entered Technical Specificatic -

(TS) 3.7.9, and the event was reported pursuant to 10 CFR 50.72(b;(1)(ii)(A).

The seguired batteries ware restored to operable status at 17:15 on November 19, 1992. TS 3.7.9 requires submittal of a safety evaluation which justifies the safest course et action to be taken in the event of ongoing degradation beyond TS 3.7.2, together with plans for expediting the return to unrestricted operating conditions.

Although the event of concern has already been resolved, the following inf ormation provides the basis for the course of action taken. Briefly, the batteries were expected to be restored in a time commensurate with TS 3.0, shutdown of any Oconee Units in reponse to this event would decrease the margin of safety fe<. the power distribution system, the probability of a seismic event while the batteries racks were undergoing repair was small, it was unlikely that an actual seismic event would result in the loss of all four batteries, and actual battery capacity is significantly greater than assumed in accident analyses.

Very Truly Yours,

fdAA J. W. Hampton f

xc: L. A. Viens, Project Manager ONRR S. D. Ebner.er, Regional Administrator Region Il P. E. Harmon Senior Resident Inspector fin 0

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