ML20207K715
| ML20207K715 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/30/1986 |
| From: | Nauman D SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| SPR-86-015, SPR-86-15, NUDOCS 8701090495 | |
| Download: ML20207K715 (2) | |
Text
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Sogmygna EW & Gas Canpane
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Co mba, 29218 Nuclear Operations SCE&G
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December 30, 1986
^ 7 J AF.' 5 A9:i d Dr. J. Helson Grace Region Administrator U. S. Nuclear Regulatory Commission Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323
SUBJECT:
Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Special Report (SPR 86-015)
Dear Dr. Grace:
Attached is a Special Report for the Virgil C. Summer Nuclear Station.
This Special Report is required by Section 6 of the Technical Specifications.
Should there be any questions, please call us at your convenience.
ry t ly yours, A Nauman RJB: DAN /bjh Attachment cc:
- 0. W. Dixon, Jr./T. C. Nichols, Jr.
G. O. Percival E. H. Crews, Jr.
R. L. Prevatte E. C. Roberts J. B. Knotts, Jr.
J. G. Connelly, Jr.
S. D. Hogge W. A. Williams, Jr.
I&E Washington Group Managers Document Management
- 0. S. Bradham Branch D. R. Moore INP0 Records Center W. R. Baehr ANI Library W. T. Frady NPCF C. L. Ligon (NSRC)
File R. M. Campbell K. E. Nodland R. A. Stough k?S861230 I
l D
S 05000395 T r /G PDR g,g g
F Dr. J. Nelson Grace SPR 86-015 Attachment December 30, 1986 EVENT DESCRIPTION On December 16, 1986, Emergency Diesel Generator (EDG)
"B" (XEG-0001B) was being operated in conjunction with maintenance activities associated with the rocker arm lube oil system. Shortly after paralleling the unit with offsite power, the EDG breaker tripped open on instantaneous overcurrent. The Shift Supervisor reviewed the unit's parameters (voltage, amps, etc.) and found them satisfactory. A second attempt was made to parallel the unit with offsite power resulting in the breaker again tripping open on instantaneous overcurrent.
Investigation by plant electricians identified the cause of this event to be a faulty silicon control rectifier gating board. The faulty component is manufactured by Basler Electric Company and is an integral part of the Static Exciter Regulator. The faulty component was replaced, the unit satisfactorily tested, and subsequently declared operable December 18, 1986. This is classified as a valid failure in accordance with the criteria of Regulatory Guide 1.108. This is the second valid failure in the last twenty tests and, as such, testing of EDG "B" is increased to every seven days in accordance with the Licensees' Technical Specifications.
Special Report 86-007, dated June 2, 1986, documents the previous failure of EDG "B".
,.