ML20151V833
| ML20151V833 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 01/29/1986 |
| From: | Zupko J Public Service Enterprise Group |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| 86-1, NUDOCS 8602110421 | |
| Download: ML20151V833 (3) | |
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O PSIEG
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Public Service Electric and Gas Company P.O. Box E Hancocks Bridge, New Jersey 08038 Salem Generating Station January 29, 1986 U. S. Nuclear Regulatory Commission Document Control Desk washington, DC 20555
Dear Sir:
SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO. 50-311 UNIT NO. 2 REPORT NO. 86-1 SPECIAL' REPORT This Special Report, describing a diesel generator test failure,is being submitted pursuant to the requirements of Technical Specification Surveillance Requirement 4.8.1.1.4.
This report is required within thirty (30) days of discovery.
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Sincerely yours, f./
4 i
J. fl. Zupko, r.
General !!anager Salem Operations JLR:ama C
Distribution
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f I l The Energy People 8602110421 060129 PDR ADOCK 05000311 S
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SPECIAL REPORT NUMBER 86-1 PLANT IDENTIFICATION:
Salem Generating Station - Unit 2 Public Service Electric & Gas Company Hancock's Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:
2B Diesel Generator Test Failure Event Date:
01/02/86 Report Date: 01/29/86 This report was initiated by Incident Report No.86-003 CONDITIONS PRIOR TO OCCURRENCE:
Mode 5 - Rx Power 0 % - Unit Load 0 MWe This special report describes a test failure 1.:volving 2B Diesel Generator occurring on January 2, 1986. 'Thi report is submitted for informational purposes in accordance with Technical Specification Surveillance Requirement 4.8.1.1.4, and contains the information required by Regulatory Guide 1.108, Revision 1, August 1977, Regulatory Position C.3.b.
Surveillance Requirement 4.8.1.1.4 states:
All diesel generator failures, valid or non-valid, shall be reported to the Commission pursuant to Specification 6.9.1.
DESCRIPTION OF OCCURRENCE:
On January 2, 1986, during Unit shutdown operations, routine surveillance testing of 2B Diesel Generator was in progress in accordance with Surveillance Procedure SP(O) 4.8.1.1.2.
Following a successful start, 2B Diesel Generator was paralleled to the 2B Vital Bus at approximately 0055 hours6.365741e-4 days <br />0.0153 hours <br />9.093915e-5 weeks <br />2.09275e-5 months <br />.
At 0122 hours0.00141 days <br />0.0339 hours <br />2.017196e-4 weeks <br />4.6421e-5 months <br />, the generator output circuit breaker opened on overcurrent protection.
The diesel was then stopped manually by the operator performing the surveillance.
APPARENT CAUSE OF OCCURRENCE:
2B Diesel Generator output circuit breaker tripped as the result of the normal starting current (approximately 4800 amps) produced when No. 23 Reactor Coolant Pump was started.
At the time of occurrence, No. 22 Station Power Transformer was supplying both the 2F Group Bus (power supply for No. 23 Reactor Coolant Pump) and the 2B Vital Bus.
Therefore, 2B Diesel Generator, which was synchronized with the 2B Vital Bus, was also synchronized with the 2F Group Bus.
When the reactor coolant pump started, 2B Diesel Generator attempted to assume this load, resulting in the output circuit breaker tripping on overcurrent protection.
The root cause has been determined to be the lack of adequate procedural guidance.
u, SPECIAL REPORT 86-1 O ANALYSIS OF OCCDRRENCE:
This diesel test failure was not the result of a diesel fault; but, instead was caused by an operational event.
The diesel generato output breaker tripped as designed to prevent a generator overload.
This event occurred because the diesel was operating in parallel with the station power transformer; this configuration occurs only during diesel surveillance testing.
During actual accident conditions, the vital busses are powered from either the diesels or the station power transformers, but not both; therefore, the starting of a reactor coolant pump (which is powered from a group bus) would have no effect on a diesel, since the vital busses are not paralleled with the group busses._
As required by the Technical Specifications during cold shutdown operations (Mode 5), two (2) diesel generator units remained in an operable status at all times.
2B Diesel Generator was subsequently tested in accordance with Surveillance Procedure SP(O) 4.8.1.1.2; the results were satisfactory and the diesel was restored to an operable status.
This event therefore involved no undue risk to the health or safety of the public.
However, as previously stated, all diesel generator test f ailures, both valid and non-valid, are required to be reported to the Commission pursuant to Specification 6.9.1.
CORRECTIVE ACTION:
The testing interval for the diesel generators, at the-time of occurrence, was fourteen (14) days as the result of the last valid diesel test failure which occurred on October 6, 1985.
This event, however, was classified as a "non-valid" test failure in accordance with Regulatory Guide 1.108, Regulatory Position C.2.e.(2).
As a result, the testing interval remained unchanged.
To prevent recurrence, Operating Procedure OP II-1.3.1 (Reactor Coolant Pump Operation) was revised to caution operators not to start a reactor coolant pump if a diesel generator is synchronized with the associated station power transformer.
adok General Manager-Salem Operations JLR:tns SORC Mtg 86-003