ML20116K784

Special Rept 92-007:on 921013,EDG 11 Started But Start Signal Indicating Light Did Not Illuminate & Local Operator Unable to Verify EDG Acceleration.Possibly Caused by Blown Bulb.Edg 11 Functional Test Successfully Performed

ML20116K784
Person / Time
Site:	Grand Gulf
Issue date:	11/11/1992
From:	Cottle W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
92-007, 92-7, GNRO-92-00135, GNRO-92-135, NUDOCS 9211180003
Download: ML20116K784 (2)

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MJ Enter 9b Opstations.Inc.

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November 11, 1992

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>*s) >L4 T * , cn U.S. Nuclear Regulatory Commission Mail Station P1-137 Washington, D.C. 20555 Attention: Document Control Deak

Subject:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 Licenso No. NPF-29 Special Report 92-007 Invalid Failure of Emergency Diesel Generator 11 Due to Start Light Not Illuminating upon Start GNRO-92/00135 On October 13, 1992, Operationc personnel prepared to r.orform a functional test of Emergency Diesel Generator (EDG) 11 in accordance with Surveillar.ce Procedure 06-OP-1P75-M-0001.

Section 5.2.8.a of the abova procedure requires the local operator to verify the EDG starts and accelerates to at least 441 RPM within ten seconds. The local operator uses a stopwatch ' to time the interval between the illumination of the red START SIGNAL indicating light and the local tachometer indicating the desired value.

The EDG was started in accordance with the above procedure and ac C.eved rated RPM. However the START SIGNAL indie t.tng light did not illuminate upon start of the EDG. Therefore the local operator was unable to verify EDG mceleration as required by procedure.

Prior to a load attempt, EDG 11 was manually shutdown to determine the cause of the condition. A tiroubleshooting work order was initiated to investigate the cause of the light not illuminating.

The start light circuit is parallel to a relay which sends a signal to the General Electric Transient Analysis Recorder System (GETARS) . During the start, GETARS received its normal signal; this gave technicians reasonable assurance that the upstream pressure switch.1P7BN094A was operating properly. Techt.icians also checked the light socket.

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L November 11, 1992 GNRO-92/00135 Page 2 of 3 During troubleshooting, no abnormal conditions were identified. It is believed that the bulb which was installed at the time of the start was blown and was subsequently changed. There were indications at the local panel that several light bulbs had been changed.

Following the investigation, a simulated EDG run was performed. The 3 start light illuminated as designed. On October 15, 1992, the EDG 11 functional test was successfully completed.

EDG 11 was intentionally shut 'n for an abnormal condition which would not have ultimately re '

in EDG damage or failuro. This condition would not have rende. the EDG incapable of perforning its intended safety function. "berefore this occurrence is considered an invalid failure of the EDG unit.

Yours truly, w y a eu.u.

WTC/RR/

cc: Mr. R. H. Bernhard Mr. D. C. Hintz Mr. R. B. McGehee Mr. N. S. Reynolds Mr. H. L. Thomas

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Mr. Stewart D. Ebneter Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta St., N.W., Suite 2900-Atlanta, Georgia 30323 Mr. P. W. O'Connor (w/2)

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C. 20555 t

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