ML20095H252
| ML20095H252 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 12/15/1995 |
| From: | Hutchinson C ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GNRO-95-00139, GNRO-95-139, NUDOCS 9512220242 | |
| Download: ML20095H252 (3) | |
Text
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Entstgy Opsrations,Inc.
cr~ ENTERGY.
Ryt G ozo MS 39150 Te 001437 2800 C. R. Hutchinson we %
Cr - in G:, I J G " N.x> y Mv December 15, 1995 U.S. Nuclear Regulatory Commission Mail Station P1-37 Washington, D.C. 20555 Attention:
Document Control Desk
Subject:
Grand Gulf Nuclear Station Docket No. 50-416 License No. NPF-29 invalid Failure of Emergency Diesel Generator 13 Due to Output Breaker Failure to Close (SR-95/004)
GNRO-95/ 00139 Gentlemen:
On November 17,1995, an invalid failure of Division 13, High Pressure Core Spray, (HPCS)
Emergency Diesel Generator (EDG) occurred. During a routine monthly functional surveillance, the EDG output breaker failed to close. The output breaker failure to close was followed by the EDG annunciator "HPCS GEN TRIP / LOCKOUT".
After two attempts to close the output breaker, the EDG was manually shut down and a Work Order was initiated to investigate the problem. Investigation revealed a faulty sync check relay in the paralleling circuit. This relay prevents the output breaker from being closed unless the EDG is in phase with the off site source. Failure of the relay in this case provided an erroneous out of phase signal, preventing the EDG output breaker from closing.
The sync check relay was repaired, and the EDG was successfully restarted and the surveillance run completed.
During test, the grid provides the load for the EDG. The paralleling circuit insures that the EDG is not loaded out of phase. On an emergency start with loss of offsite power, or degraded bus voltage, the paralleling circuit is bypassed. Failure of the sync check relay would not prevent the EDG from performing its design function during an emergency.
Therefore, this failure of EDG 13 has been classified as an invalid failure.
9512220242 951215
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- December 15, 1995 GNRO-95/ 00139 Page 2 of 3 This report of an invalid failure of EDG 13 is made in accordance with the requirements of Grand Gulf Technical Requirements Manual section 7.7.2.2.
Yours truly 48(A_
ja c U CRH/JEO/
cc:
Mr. J. E. Tedrow (w/a)
Mr. H. W. Keiser (w/a)
Mr. R. B. McGehee (w/a)
Mr. N. S. Reynolds (w/a)
Mr. Leonard J. Callan (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 Mr. P. W. O'Connor, Project Manager (w/2)
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission l
Mail Stop 13H3 Washington, D.C. 20555 I
O*
' December 15, 1995 GNRO-95/ 00139 Page 3 of 3 bec:
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