ML20098D695
| ML20098D695 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/26/1992 |
| From: | Bailey J WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 92-001, 92-1, NO-92-0156, NO-92-156, NUDOCS 9205290281 | |
| Download: ML20098D695 (3) | |
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WOLF CREEK
' NUCLEAR OPERATING CORPORATION John A. Dailey Vice F.esident operations May 26, 1992 NO 92-0156 U. S. Nuclear Regulatory Commission ATTN:
Document Control Desk Mail Station P1-137 Washington, D. C.
20555
Subject:
Docket No. 50-482:
Special Report 92-001 s'
Gentlement The attached Spacial Report is being submitted in accordance with Technical Specification 4.8.1.1.3 concerning an invalid fai'.ure of Emergency Diesel Generator
'A".
Very truly yours,
(.ij /td L
- BA m
John A. Ball y k
Vice President Operations JAB /aem cc:
A. T. Howell (NRC), w/a R. D. Martin (NRC), w/a G.
A. Pick (NRC), w/a W. D. Reckley (NRC), w/a e
9205290281 923526 PDR ADOCK 05000402 PDR PO. Box 411/ 9urbngton, KS 06839 i Phone: (316) 364-883;
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- - Attachment to NO 92-0156 Page_1 of 2 j
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SPECIA1. REPORT 92-001 Invalid Failure of Emernency Diesel Generator "A"_
This report describes an invalid failure of Emergency Diesel Generator (EDG)
"A" which occurred an April 13, 1992.
This report is being submitted in accordance with Technical Specifications 4.8.1.1.3 and 6.9.2.
DESCRIPTION OF EVENTS On April 22,19i:4 at 0300 CDT, EDG "A' was taken out of service for maintenance.
Following ccmpletion of maintenance activities on April 23, 1992, surveillance procedure SIS KJ-005A, " Manual / Auto Start, Synchronization, and Loading of Emergency U.esel Generation NE01", was commenced to prove operability of EDG "A" prior to placing it back in service.
The EDG was started at 2216 CDT and at 2225 CDT the operator l
closed the EDG output breaker and began to apply load.
Pursuant to l_
surveillance procedure STS KJ-005A, the EDG was immediately loaded to 0.2 l
Megawatts (MW), as indicated in the Control Room, by operating the governor speed control uwitch.
Shortly after the EDG output breaker tripped on reverse power.
It was then decided that the EDG should be loaded to 0.5 MW instead of 0.2 MW to ensure that the EDG output breaker would remain closed. The operator reset and reclosed the output breaker and applied a load of 0.5 MW.
The output breaker remained closed with the additional load.
The EDG was operated at full load for one hour and the surveillance procedure was successfully completed.
Following completion of the surveillance procedure, EDG "A" was declared operable at 0340 CDT on April 24, 1992.
This event had no effect on the teliability cr availability of the EDG.
- LOOT CAUSE AND CORRECTIVE ACTIONS An investigation following the event determined that the MW meter used in the Controt-Room to load t he EDG was reading 0.2 MW with the _ EDG idle and in standby.
Loading the EDG to an indicated 0.2 FST would actually result in a real power level of approximately zero.
This would result in the output breaker opening on reverse power.
This function protects the generator from motoring when connected to an energized bus.
The MW meters for EDGs "A* and "B" have been rezeroed to ensure that the proper load is added to the EDGs. Also, a work request was initiated to examine an apparent. drift when the EDG was loaded.
The operator noted that the EDG Joad appeared to drift downward prior to the EDG output breaker tripping on reverse power. The governor for EDG "A" was determined to be functioning properly.
Surveillance procedures STS KJ-005A and STS KJ-005B o
bsve been revised to require the operator to immediately load the EDG to approximztely 0.5 MN instead of 0.2 FSI.
Attachment to NO 92-0156 Page 2 of 2 4
Fj. LURE CLASSIFICATION The EDG output breaker reverse power trip function is no-required and does not operate in the emergancy operating mode.
Therefore, the unsuccessful load attempt discussed in this report is considered to be an invalid test and failure in accordance with Regulatory Position C.2.e(2) of Regulatory Guide 1.l'8, Revision 1.
It does not affect the current surveillance test interval of 31 cays as required by Tr.ble 4.8-1 of Tecnnical Specification 3.8.1.1.
Through April 23, 1992, there have been s.nree valid and three invalid failures of EDG *a" in the last 100 valid tests.
From the time of the last valid failure of EDG "A"
on December 11, 1987, ZDG "A" has undergone 77 successful valid tests.
The last invalid failure of EDG
- A" occurred on November 21, 1991.
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