ELV-03687, Special Rept:On 920331,K1 Relay to Latch in Closed Position & Short Generator Field.Caused by Spring Load Collar Not Fully Returning to Normal Position.Appropriate Procedures Will Be Changed by 920615 to Ensure Collar Is Checked

Special Rept:On 920331,K1 Relay to Latch in Closed Position & Short Generator Field.Caused by Spring Load Collar Not Fully Returning to Normal Position.Appropriate Procedures Will Be Changed by 920615 to Ensure Collar Is Checked

ML20095J024
Person / Time
Site:	Vogtle
Issue date:	04/27/1992
From:	Mccoy C GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ELV-03687, ELV-3687, NUDOCS 9205010034
Download: ML20095J024 (2)

Text

/ s Georg-a Pew Com;mny etO InverneM Cem!W Pa%3y Post OPce Box 1295 B tm.ngnam_ Ahnama J5201 Tee;> hone 205 877 71'2 m

C. K. McCoy Georgia Power vce Pm.ev. nm Vggfe PrC o ! ff't; SOuf hern (n ! 6 ylp<

April 27,1992 ELV-03687 001614 Docket No. 50-425 U. S. Nucinr Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 i Gentlemen:

V0GTLE ELECTRIC GENERATING PLANT SPECIAL REPORT INVALID DIESEL GENERATOR FAILVRE In accordance with the requirements of the Vogtle Electric Generatinti Plant Technical Specifications, sections 4.8.1.1.3 and 6.8.2, Georgia Power Company hereby submits the enclosed Special Report concerning an invalid diesel generator failure.

Sincerely, C. K. McCoy CKM/NJS/gmb

Enclosure:

Special Report 2-92-4 xc: Georaia Power Company Mr. W. B. Shipman Mr. M. Sheibani NORMS l U. S. Nuclear Reaulatory Commission l Mr. S. D. Ebneter, Regional Administrator Mr. D. S. Hood, Licensing Prcject Manager, NRR Mr. B. R. Bonser, Senior Resider.t Inspector, Vogtle 1

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V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 TECHNICAL SPECIFICATION SPECIAL REPORT 2-92-4 INVALID DIESEL GENERATOR 2B FAILURE A. REQUIREMENT FOR REPORT This report is required in accordance with the Vogtle Electric Generating Plant Technical Specifications (TS), section 4.8.1.1.3, which requires all diesel generator (DG) failures, valid or invalid, be reported to the Commission in a Special Report pursuant to TS 6.8.2.

B. DESCRIPTION OF INVALID FAILURE OF DIESEL GENERATOR 28 l Following its once per 18 month overhaul, DG 2B underwent several maintenance tests to prime, aiibrate, or verify the-functioning of various DG components. f:lthough thne tests identified problems, which were corrected as interded, one of the tests is considered to be an invalid failure per Regulatory Guide 1.108.

On March 31, 1992 at 1618 EST, DG 2B was successfully started to set the governor. After venting the mechanical governor, personnel made several attempts to -excite the generator field in order to place the electrical governor in operation, but were unable to do so. The DG was stopped at 1658 EST.

-An-investigation found a closed microswitch on the bridge transfer switch, causing the K1 relay to latch in the closed position and short the generator field. The microswitch has a collar which moves on the transfer switch shaft. When the transfer switch was released during the overhaul, the spring loaded collar did not fully return to its normal position. The 4

collar was manually returned to the normal position, and DG testing contin *;ed. The appropriate procedures will be changed by June 15, 1992, to ensure that the collar is checked for proper positioning.

-C.

SUMMARY

Following completion of the maintenance testing and a valid surveillance test, DG 2B was declared operable and restored to service on April 3, 1992.

Diesel generator _2B has experienced one valid failure in the last 20 valid tests and 3 valid failures in a total of 78 valid tests. The test frequency remains at-once per 31 days in accordance.with the requirements of TS table 4.8-1.

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