ML20063H673
| ML20063H673 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 02/14/1994 |
| From: | Hutchinson C ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 94-001, 94-1, GNRO-94-00024, GNRO-94-24, NUDOCS 9402220115 | |
| Download: ML20063H673 (2) | |
Text
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Entirgy Optritlins,Inc.
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i C. R. Hs tchinson vce an en:
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- Qwiiv, Gand as ficket Swon I'
l February 14,1994 l
U.S. Nuclear Rejuls y Commission i
Mail Station P1-137 i
Washington, D.C. 20555 Attention:
Document Control Desk
Subject:
Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Special Report 94-001 Invalid Failure of Standby Diesel Generator 12 Due to False High Jacket Water Temperature Signal GNRO-94/00024 Gentlemen:
Division 2 Standby Diesel Generator (SDG 12) experienced an invalid failure during surveillance on January 13,1994. SDG 12 was started in accordance with plant operating instructions and reached rated speed and voltage. However, automatic j
shutdown occurred as a result of a Group 2 trip signal approximately thirty minutes into the run.
Investigation revealed that the trip occurred due to a spurious high Jacket water temperature signal that was generated by a faulty jacket water temperature switch (1P75N162B). The switch vented pressure from the pneumatic trip system at temperatures below its normal trip setpoint of 20013 degrees F. Bench testing determined that the switch tripped at approximately 154 degrees F. The switch was replaced and tested.
A previous failure of SDG 12 occurred on May 21,1993 due to the same condition.
Corrective actions performed at that time have not been determined to have contributed to this event. Investigation of this event is continuing to assess the need for additional corrective actions. Corrective actions will be developed based on investigation findings.
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GNRO-94/00024 Page 2 of 3 The SDG trip is attributed to the malfunction of equipment'that is not operative in the emergency operating mode. Therefore, this occurrence is considered an invalid failure.
of the SDG unit. There have been no valid failures of SDG 12 in its last 100 tests; SDG 12 was retested satisfactorily at 19:39 on January 14,1994. SDG 12 was unavailable for 22.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
j Yours truly,
/ // /.-
1 CRH/MJM/LFD/BAB/
cc:
Mr. R. H. Bernhard Mr. H. W. Keiser c
Mr. R B. McGehee l
Mr. N. S. Reynolds Mr. H. L. Thomas t
l Mr. Stewart D. Ebneter 1
Regional Administrator.
U.S. Nuclear Regulatory Commission Region 11 101 Marietta St., N.W., Suite 2900 Atlanta, GA 30323 l
Mr. P. W. O' Connor (w/2)
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Ster C93 J
Washington, D.C. 20555 -
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