RBG-37720, Special Rept:On 921013,Div I EDG Automatically Shutdown During Regular Monthly Surveillance Test.Caused by Failure of Shutdown Control Valve P-4.Valve Replaced & Surveillance Test Completed Approx 12 H After Valid Failure

Special Rept:On 921013,Div I EDG Automatically Shutdown During Regular Monthly Surveillance Test.Caused by Failure of Shutdown Control Valve P-4.Valve Replaced & Surveillance Test Completed Approx 12 H After Valid Failure

ML20116L115
Person / Time
Site:	River Bend
Issue date:	11/10/1992
From:	Odell W GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RBG-37720, NUDOCS 9211180171
Download: ML20116L115 (4)

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GULF- fiTATES ~ UTILXYXES COMPANY.

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November-10, 1992 '

. RBG- 377?0- _y File Nos. G9.5,; G9.25.1.3 U.S. Nuclear Regulatory Commission . N Document Control Desk J Washington, D.C. 20555 '

Gentlemen:

2 River Bend Station . Unit 1- ---- -

Docket No. 50-458 Enclosed is Gulf States Utilities Company's Special Report concerning an invalid

- failure of the Division I diesel generator at River Bend-Stationj(RBS);e This : .

report is submitted parsuant to RBS Technical Specification 4.8.1;1 '3 and 6.9 2. - -

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Manager Oversight .

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cc: U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 NRC Resident Inspector P.O. Box 1051 St. Francisville, LA 70775 INPO Records Center 1100 Circle Parkway Atlanta, GA 30339-3064 Mr. C.R. Oberg Public Utility Commission of Texas 7800 Shoal Creek Blvd., Suite 400 North Austin, TX 78757 Louisiana Department of Environmental Quality Nuclear Energy Division P.O. Box 82135 Baton Rouge, LA 70884 2135 ATrN: Administrator

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- SPECIAI, REPORT KlilMIHi]) CONI)UJON On October 13, 1992, with the reactor operating at 100 percent power (Operational Condition 1), the Division I emergency diesel gerierator (EDG) automatically shutdown during the regular monthly surveillance test due to a failure of shutdown control valve P-4, constituting an invalid failure. This Special Report is pro'ided in accordance with Technical Specification 4.8.1.1.3 and Regulatory Guide 1.108.

INVFSTIDATIO.B On October 13,1992, surveillance test procedure (STP)-309-0201 was being perfonned on the Division I eniergency diesel generator to fulfilllechnical Specification month _ly surveillance seguirements. The emergency diesel georatar was started and mn for approximately two minutes before shutting down automatically. The diesel operating parameters were connal and no annunciators were illuminated to indicate the cause of the shutdown.

CAUSE OF FAILURF A mainter.ance work order (MWO) was initiated to detennine the cause of the engine shutdown.

The investigation detennined the cause to be the failure of shutdown control valve P-4 in the .

group II pneumatic shutdown logic circuit. The control valve was replaced and the surveillance test was completed approximately 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after the invalid failure. Shutdown control valve P-4 is bypassed during emergency starts. Therefore this failure is not a valid failure of the EDG, but does constitute an invalid failure.

Prior to the start and automatic shutdown, the EDG was started and manually shutdown due to an unrelated equipment problem. Therefore, the failure of shutdown contial valve P-4 occurred after the first start attempt.

CORREC'QVE ACTION Shutdown control valve P-4 was replaced under prompt MWO R059323. A nonnal SOP-0053 nm was conducted after the P4 valve was replaced. STP-309-0201 was successfully completed a few hours after the SOP nm. All operating paramcters were reported normal during_ the performance of both nms.

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., s-Ihiesel Gengntor Unit Designation and Nuniber:

Division I, LEGS *EGI A Length of ti:nc Unavailable: 10.3 hrs Current Surveillatigs_Tcst Interval: 31 Days Test Interval Confonns to Technical Specification: Yes Ecibires for Division I EDG:

0 valid failures in last 20 valid test 2 valid failures in last 100 valid test Number of Valid Failures in Previous 100 Valid Tests of ALL DGs at River Bend Station: 'O i

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