ML20086B892

Special Rept 2-95-3:on 950607,three non-valid DG2A Failures Occurred Due to Malfunctioning Automatic Min Excitation Limiter.Malfunctioning Automatic Min Excitation Limiter Removed from Service

ML20086B892
Person / Time
Site:	Vogtle
Issue date:	06/29/1995
From:	Mccoy C GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2-95-3, LCV-0632, LCV-632, NUDOCS 9507060155
Download: ML20086B892 (2)

Text

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IGeorsa Power Cornpani: . '

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= Post offce Box 1295 y Birmingham. Alabama 35201

.,j . Tetephone 205 877 7122 lt C c.x. uccoy .. Georgia Power 1

- Vce Pre 9dervt Nuclear Vogtte Progect .

tre southern electic system i June 29, 1C , q t

LCV-0632 . l t-Docket No. 50-425 ,

I U. S. Regulatory Commission j f

. ATTN: Document Control Desk -

Washington, D. C. 20555 {

l Gentlemen: j

> l

.VOGTLE ELECTRIC GENERATING PLANT l SPECIAL REPORT 2-95-3 .!

DJESEL GENERATOR FAILURES .!

In accordance with the requirements of Vogtle Electric Generating Plant Technical  !

Specifications (TS) sections 4.8.1.1.3 and 6.8.2, Georgia Power Company submits the l enclosed special report concerning diesel generator failures.

- Sincerely, M'

. C. K. McCoy CKMfrEW

Enclosure:

Special Report 2-95-3 xc: Georgia Power Comoany Mr. J. Bl Beasley, Jr.

Mr. M. Sheibani NORMS U. S Nuclear Regulatory Commission Mr. S. D. Ebneter, Regional Administrator Mr. D. S. Hood, Licensing Project Manager, NRR Mr. B. R. Bonser, Senior Resident Inspector, Vogtle s-

m. ..

O

. VOGTLE ELECTRIC GENERATING PLANT - UNIT 1

. TECHNICAL SPECIFICATION SPECIAL REPORT 2-95-3 DIESEL GENERATOR (DG) FAILURES

' A. REQUIREMENT FOR REPORT l This report is required in accordance with the Vogtle Electric Generating Plant i Technical Specifications (TS), section 4.8.1.1.3, which requires that all diesel I generator (DG) failures, valid or non-valid, be reported to the Commission in a special report pursuant to TS 6.8.2.

B. DESCRIPTION OF FAILURES OF DIESEL GENERATOR 2A On June 7,1995, at 1206 EDT, DG2A was started for a monthly surveillance iest.

Generator output voltage rose to 5000 volts and could not be lowered by control ,

room operators. At 1208 EDT, DG2A was shutdown for troubleshooting and was  !

removed from service. Three additional DG starts were conducted to identify the cause of the high voltage. Each of these three starts was classified as a non-valid failure because it exhibited the same problem as the original failure. The automatic I minimum excitation limiter was found to be malfunctioning and was removed from l service. The function of this excitation limiter is to increase excitation prior to the l generator reaching its leading power factor stability limit. During emergency operation of the diesel, the loads are inductive which is a lagging power factor.

Procedures used for completion of surveillance and maintenance testing also require operation with a lagging power factor. Therefore, the automatic minimum i excitation limiter has no function during emergency operation or normal testing i l

and the intent is to remove this excitation limiter from service for the other emergency DGs. DG2A was successfully tested and returned to service on June 8, 1995, at 0923 EDT.

l 1

I C.

SUMMARY

The DG2A start ofJune 7,1995, at 1206 EDT, has been determined to be a valid failure because it could have affected the engine's emergency start capability.

DG2A has had 1 valid failure in the last 20 valid tests and 1 valid failure in the last 100 valid tests. The test frequency for DG2A remains at once per 31 days in accordance with the requirements of TS table 4.8-1.

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