ML20211G449

Special Rept Spr 86-007:on 860504,during post-test Review of Operating Log,Mfg Recommended Differential Temp of 150 F Between Exhaust Cylinders Exceeded by 20 F.Caused by Timing of Injector Pumps.Timing Reset

ML20211G449
Person / Time
Site:	Summer
Issue date:	06/02/1986
From:	Nauman D SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
SPR-86-007, SPR-86-7, NUDOCS 8606190423
Download: ML20211G449 (2)

Text

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• 22 Dr. J. Nelson Grace Regional Administrator U. S. Nuclear Regulatory Commission Region II, Suite 2900 101 Marietta Street, N.W.

Atlanta, Georgia 30323

SUBJECT:

Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Special Report (SPR 86-007)

Dear Dr. Grace:

Attached is a Special Report for the Virgil C. Summer Nuclear Station.

This report is submitted pursuant to the requirements of Section 6 of the Technical Specifications.

Should there be any questions, please call us at your convenience.

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.r y~ yours,

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D.

aaman RJB: DAN / led Attachment pc:

0. W. Dixon, Jr./T. C. Nichols, Jr.

K. E. Nodland E. H. Crews, Jr.

R. A. Stough E. C. Roberts G. O. Percival J. G. Connelly, Jr.

R. L. Prevatte W. A. Williams, Jr.

J. B. Knotts, Jr.

Group Managers S. D. Hogge

0. S. Bradham I&E Washington D. R. Moore Document Management C. A. Price Branch W. T. Frady INP0 Records Center C. L. Ligon (NSRC)

ANI Library R. M. Campbell NPCF File 8606190423 860602 DR ADOCK 0500 5

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• 'r Dr. J. Nelson Grace SPR 86-007 June 2, 1986 ENCLOSURE 1 EVENT DESCRIPTION On May 4, 1986, scheduled surveillance testing was satisfactorily performed on Diesel Generator "B".

During post test review of the operating log, it was identified that the manufacturer's recommended differential temperature of 1500F between exhaust cylinders had been exceeded by 200F. Diesel Generator "A" was verified to be operable and a maintenance work request was initiated for the investigation and repair to Diesel Generator "B".

The cause of the high temperature was identified to be the timing of the injector pumps. The timing of the injector pumps was reset and post maintenance testing initiated.

At approximately 0855 hours0.0099 days <br />0.238 hours <br />0.00141 weeks <br />3.253275e-4 months <br /> on May 6, 1986, during a post maintenance run with the unit loaded at 2125 KW, the unit tripped. Subsequent investigation identified the cause to be the failure of a Voltage-Frequency Regulator Control Circuit Board in the voltage regulator circuitry. The failed circuit board was replaced, the unit was satisfactorily tested and was declared operable at 0820 hours0.00949 days <br />0.228 hours <br />0.00136 weeks <br />3.1201e-4 months <br /> on May 7, 1986.

CONCLUSION Exceeding the manufacturer's recommended differential temperature does not constitute a test failure. The 1500F value is a performance limit while the maximum manufacturer's limit for operation of the unit is l

2000F. Surveillance testing of the unit had been completed and the unit was operable when removed from service.

The failure of the Voltage-Frequency Regulator Control Board is a test l

failure. This is the second failure in the last one hundred valid tests and the first in the last twenty valid tests. Special Report 85-004,

(

dated June 7, 1985, documents the previous failure.

Testing of the Diesel Generator is being performed once per thirty-one days in accordance with Amendment No. 50 to the Licensee's Technical l

Specifications.

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