ML20011F562

Special Rept 2-90-02:on 900124 & 25,when Start Button Depressed,Diesel Generator 2A Rolled Slowly for Approx Two Turns But Did Not Start.On 900201,when Diesel Paralleled to Grid,Low Excitation Alarm Received.Bridge Circuit Repaired

ML20011F562
Person / Time
Site:	Vogtle
Issue date:	02/19/1990
From:	Hairston W GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2-90-02, 2-90-2, ELV-01353, ELV-1353, NUDOCS 9003060269
Download: ML20011F562 (3)

Text

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~i Categia Power Cbmpany

333 P,iutmon! Am*,ao I O. At.anta Geo;)a 30338

.M Tsephone 434 L?6 3196 Y unamm

• 40 IMirren Conter Pdway so lict 0% Box 1?95 tFrm naham. Alabama 35201 L w .n u eost u suo l

February 19, 1990 .. , , . . , , , , , , , , , ,

W. G. Hairston, Ill L

sew vce rrewi, Nant r Operahans ELV-01353 0243

[ Docket No. 50-425

U. S. Nuclear Regulatory Commission ATTN

Document Control Desk p Washington, D. C. 20555 Gentlemen:

V0GTLE ELECTRIC GENERATING PLANT SPECIAL REPORT VAllD DIESEL GENERATOR FAILVRES In accordance with the requirements of the Vogtle Electric Generating Plant Technical Specifications, Sections 4.8.1.1.3 and 6.8.2, Georgia Power Company is submitting the enclosed Special Report concerning valid diesel generator

- failures.

!. Sincerely.

././ W

. G. Hairston, 111 WGH,lil/NJS/gm

Enclosure:

Special Report 2-90-02 xt: Georaia Power Comna01 Mr. C. K. McCoy Mr. G. Bockhold, Jr.

Mr. R. M. Odom Mr. P. D. Rushton NORMS U. S. Nuclear Reaulatory Commission b' Mr. S. D. Ebneter, Regional Administrator Mr. D. B. Matthews, Director, Project Directorate 11-3 Mr. R. F. Aiello, Senior Resident inspector, Vogtle i

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.9003060269 900219

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t ENCLOSURE V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 TECHNICAL SPECIFICATION SPECIAL REPORT 2-90-02 VAllD DjfSEL GENERATOR FAllDRES A. REQUIREMENT FOR REPORT n' This report is required in accordance with the Vogtle Electric Generating Plant Technical Specifications, Section 4.8.1.1.3. This section of the Technical Specifications requires that all diesel generator failures, valid or non-valid, be reported to the Commission in a Special Report pesuant to 3

Technical Specification 6.8.2.

B. DESCRIPTION OF VAllD FAILURES FOR DIESEL GENERATOR TRAIN A (1) On January 24, 1990 Diesel Generator (DG) 2A was scheduled to be started for the monthly surveillance. When the start pushbutton was depressed, the diesel rolled slowly for approximately 2 turns, but did ,

not start. One air receiver had been isolated, as required by procedure, to test independent starting. The operator noticed an air leak from one of the right bank air start blocking valve solenoids.

Assuming this to be the problem, he opened the isolated air receiver and attempted to start the diesel. The diesel was started and the surveillance completed with no further problems. Subsequent ,

investigation revealed that the leaking solenoid could not have caused the failure since it was associated with the isolated air receiver. No other cause for the failure could be found and, since the diesel was successfully started, it was declared operable. During this time, DG2A was out of service for 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> and 20 minutes. The leaking solenoid has subsequently been repaired.

(2) On January 25, 1990, DG2B was taken out of service after a successful test due to a problem with the stopping light. As a result, DG2A had to be tested again to satisfy the Technical Specification action requirements. Neither air receiver was isolated and when the start pushbutton was depressed, the diesel rolled slowly but did not start.

When operators attempted another start, the engine started and the surveillance was completed. Realizing this failure was similar to the one the day before in which one air receiver was isolated, operators did not return the diesel to service upon completion of the surveillance.

Troubleshooting included replacing the air start distributor filters and checking the operation of the governor, the fuel racks, the fuel l

system and the air start valves in the cylinders. No apparent problems were found and the engine was started 2 consecutive times with no other probl ems .

The engine was started a third time and a normal surveillance was completed. The diesel was returned to service. During this time, DG2A was out of service for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> and 54 minutes. Both diesels were out of service simultaneously for a period of I hour and 56 minutes.

pr 3

ENCLOSURE (CONT'D)

V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 ,

i

• TEGINICAL SPECIFICATION SPECIAL REPORT 2-90-02 i yAllD DIESEL GENERATOR FAILURES l-(3) On february 1,1990 DG2A was again started to complete Technical Specification surveillance requirements which had been increased to ,

every 7 days due to the past two valid failures. The diesel started;

, however, when paralleled with the grid, a low excitation alarm was received and reactive load exceeded stability limits. The DG output i- breaker was tripped and the generator was switched to the opposite independent rectifier bridge pe The DG was paralleled with the grid again /rndthetheoperating procedure.

surveillance was completed with no further problems. Upon satisfactory completion of the surveillance, DG2A was declared operable. The bridge circuit has subsequently been repaired. As a result of this failure, DG2A was out of service for 4

. hours and 1 minute. >

C.

SUMMARY

These were the first three valid failures on DG2A and the test frequency has been increased to once every 7 days in accordance with Table 4.8-1 of the 1 Technical Specifications. This frequency will be continued until 7 consecutive valid tests are completed and one or less valid failures have occurred in the last 20 valid tests. There have been a total of 41 valid tests of DG2A.

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