ML20203B558

Special Rept 97-003:on 971111,valid Failure of Div 2 EDG Occurred,Due to Jacket Water Leak.Failure Reported,Per Plant Technical Requirements Manual Section 7.7.2.2

ML20203B558
Person / Time
Site:	Grand Gulf
Issue date:	12/04/1997
From:	Hughey W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
97-003, 97-3, GNRO-97-00117, GNRO-97-117, NUDOCS 9712150089
Download: ML20203B558 (2)

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O g Entergy operctions,ine.

0- - Ih[hy P.O. Box 756 Port Gtson, MS 39150 O/

Tei G01437-0470

- W. K. Hughey savty & Amatay

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December 4, 1997 U. S. Nuclear Regulatory Commission Mail Station P1-37 Washington, D.C. 20555 Attention: Document Control Desk

Subject:

Grand Gulf Nucicar Station Docket No. 50-416 License No. NPF-29 Special Report 97-003 Valid Failure of Division 2 Emergency Diesel Generator Due to a Jacket Water Leak GNRO-97/00117 Gentlemen:

k On November 11,1997, Grand Gulf Nuclear Station (GGNS) operators performed an SOI maintenance run on the Division 2 Emergency Diesel Generator (EDG). The maintenance run was part of retesting to verify adequacy of routine maintenance which had just been completsd.

Several minutes into the run, several 90* elbow Dresser Couplings developed minor leaks. The couplings were tightened and the leaks stopped.

The EDG was restarted for a surveillance run. During the surveillance run, a jacket water leak developed at a straight Dresser Coupling joint. The leak rate was only drops per minute until the end of the surveillance run. During the process of securing the EDG following completion of the surveillance run, the leak increased to an estimated rate of approximately a pint per minute.

The EDG was secured arid both straight Style 60 Dresser Couplings were replaced with Style 90 Dresser Couplings. An SOI maintenance run was performed to verify no leakage from the replacement couplings and the EDG was retumed to operable status. Additionally, as mentioned in Special Report 97-002, dated October '6,1997, Dresser Coupling modifications

- on the Divisions 1 & 2 EDGs will be performed during the next system and refueling outages, it was conservatively detennined that the pint per minute leak may have prevent the EDG from completing its required seven day run without operator action. Therefore, GGNS is reporting this as a valid failure of the Division 2 EDG.

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+ December 4, 1997 GNRO-97/00117 Page 2 of 3 This valid failure of the Division 2 EDG was the third valid failure in the last 25 valid tests and the fourth valid failure in the last 100 valid tests. The unavailability time associated with this failure was 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> and 24 minutes. This was the time required to replace the Style 60 Dresser Couplings with Style 90 Dresser Couplings. This failure is being reported pursuant to Grand Gulf Technical Requirements Manual section 7.7.2.2.

Yours truly, T [0+

WKH/JEO cc: Ms. J. L. Dixon-Herrity, GGNS Senior Resident (w/a)

Mr. N. S. Reynolds (wla)

Mr. L. J. Smith (Wise Carter) tw/a)

Mr. H, L. Thomas (w/o)

Mr. J. W. Yelverton (wla)

Mr, J. N. Donahew, Project Manager (w/2) I Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D. C. 20555 Mr. E. W. Merschoff (w/a)

Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington,TX 76011 1

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