ML20044F761

Special Rept:On 930409,discovered That Battery Voltage for Triaxial Seismic Swtiches at Reactor Bldg Mat Elevation 70 ft,0 Inches Read Low at 10.6-volts Dc.Caused by Failure to Communicate LCO During Outage.Battery Replaced

ML20044F761
Person / Time
Site:	River Bend
Issue date:	05/19/1993
From:	Booker J GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RBG-38530, NUDOCS 9306010020
Download: ML20044F761 (3)

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GULF STATES Nut h EIK)I T A. TION UTELITIES COMPANY 0037 Of FCE BOM 22?

e6 57 SFANCISVILLE. LOOTS 4AN A 73775 ARE A C GDP M4 t M f#+4 346 bus 1 May 19, 1993 RBG- 38530 File Nos. G9.5, G9.25.1.3 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Gentlemen:

River Bend Station - Unit 1 Docket No. 50-458 Enclosed is Gulf States Utilities Company's Special Report concerning an inoperative seismic instrument at River Bend Station. This report is submitted pursuant to River Bend Station Technical Specification 3.3.7.2 and 6.9.2.

Sincerely,

. TN '

gr+-J.E. Booker Manager - Safety Assessment &

Quality Verification River Bend Nuclear Group 1If 15b LAE/JPS/FRC/D(f1W. CH/GRK/kym &

250020 9306010020 930519 /*

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. i cc: U.S. Nuclear Regulatory Commission I 611 Ryan Plaza Drive, Suite 400 l Arlington, TX 76011 NRC Resident Inspector P.O. Box 1051  :

St. Francisville, LA 70775 i INPO Records Center 1100 Circle Parkway I Atlanta, GA 30339-3064 I

Mr. C.R. Oberg Public Utility Commission of Texas i 7800 Shoal Creek Blvd., Suite 400 North  !

Austin, TX 78757 j i

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m INTRODUCTION i

On 4i 9-93, - during the monthly channel check of seismic monitoring instmmentation, it was noted that the battery voltage for ERS-NBS4B (triaxial seismic switches - reactor building mat elevation 70' 00") was reading low at  !

10.6 volts d.c. Technical Specifications require the battery voltage to be at least 11.5 volts dc. The instrument was declared inoperable and_ the action statement ,

of Technical Specification 3.3.7.2 was entered. This permits 30 days for restoration, otherwise a Special Report is required within the following 10 days. ,

The battery was replaced and the seismic instmmentation returned to service 7 1 days following expiration of the 30 day time limit.  !

t INVESTIGATION A maintenance work order was written to replace the battery for ERS-NBS4B.

The model of battery available as a replacement was not the same as that ,

specified by the original equipment manufacture. This required a design change to be initiated and approved prior to procurement and installation of the -  !

replacement battery. The design change and subsequent procurement and .

maintenance pmcess did not allow this component to be returned to service within the 30 day time limit. The need to expedite the procurement and maintenance 1 process was not recognized due to plant outage activities. i The rou cause was the lack of a method to communicate active limiting condition f fer opemtion (LCO) work during plant outages to appmpriate staff. Tlus was '

determined by personnel interview and documentation review. .

CORRECTIVE ACTION To prevent recurrence, a method is being developed to communicate active LCO work to applicable staff. Implementation is expected prior to July 31,1993.  ;

The battery has beca replaced and the affected seismic instmmentation has been returned to service. In order to prevent recurrence of this event, a preventive maintenance task will be developed to replace the battery in the seismic instrumentation system at a frequency that will preclude it from reaching its service life. The preventive maintenance task will be developed by June 30, 1993.

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