ML20065R602

Special Rept SR-90-003-00:on 901112,invalid Failure of Emergency Diesel Generator a Occurred.Caused by Mechanical Failure of 30 Psig Reducer in Control Air Sys & Crack on Spring Cap of Reducer.All Reducers Inspected

ML20065R602
Person / Time
Site:	Waterford
Issue date:	12/12/1990
From:	Mcgaha J ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
SR-90-003-00, SR-90-3, W3A90-0483, W3A90-483, NUDOCS 9012190101
Download: ML20065R602 (4)

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U.S. Nuclear, Regulatory Commission ATTENTION: Document Control Desk.

Washington, D.C.- 20555

SUBJECT:

~ -Waterford 3'SES Docket No. 50-382 License No. NPF-38 Reportina of Soecial Report Gentlemen:

. Attached is Special Report Number SR-90-003-00 'for Waterford Steam Electric Station Unit 3. This Special Report is submitted per .10CFR50. 3 6 (c) (2 ) and Technical Specifications 4.8.1.1.3 and 6.9.2.-

Very truly yours,-

J.R. McGaha

{ .IGeneralLManager-Plant Operations JRM/JEF:glp

' Attachment-cc:: Messrs. R.D. Martin-G.L.'Florreich J.T. Wheelock.- INPO Records Center

'E.L. Blake D.L. Wigginton' NRC Resident Inspectors Office o

F9012190101'901212 IE2.2

-PDR- ADOCK 05000382

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SPECIAL REPORT-SR-90-003-00 Invalid Failure of Emergency Diesel Generator 'A' Due to a Control Air Reducer Failure INTRODUCTION

'At 1333 hours0.0154 days <br />0.37 hours <br />0.0022 weeks <br />5.072065e-4 months <br /> on November 12, 1990, Waterford Steam Electric Station Unit 3 was operating at 100% power when Emergency Diesel Generator (EDG) 'A' failed to

' start during the performancesof "EDG-Operability Verification Operating Procedure", OP-903-068.. This event has been classified as an invalid failure._

The. root cause of the event is a mechanical failure of the 30 psig reducer in

'the EDG 'A control air system.' This reducer provides air to the pneumatically Joperated. fuel control' valve (FCV). During normal starts, this FCV vents air to operate the fuel control cylinder which in-turn positions the injector fuel

racks'to'the "on" position. Since 30 psig air was-not avai' ble, the FCV would not allow the fuel control cylinder to move. The pneumatically operated FCV is in series with two electrically operated-emergency mode FCVs. Operation of~any one:of'these FCVs will vent air to operate the fuel' control cylinder. The pneumatically operated FCV_in not required in the1 emergency mode and would not have'affected the abilitylof the'EDG to perform its design safety function.

Therefore, there was.no hazard to plant equipment or the health and safety of the general public.

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-h NARRATIVE At 1333 hours0.0154 days <br />0.37 hours <br />0.0022 weeks <br />5.072065e-4 months <br /> on November 12, 1990, Waterford Steam Electric Station Unit 3 was operating at 100% power when Emergency Diesel Generator (EDG) 'A' failed to start during performance of. operating procedure Op-903-068, "EDG Operability Verification". At 1449 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.513445e-4 months <br />, another attempt was made to start EDG 'A'.

After cranking for approximately ten seconds, the operator returned the control switch to "off". The EDG 'A' fired briefly after the control switch was taken to "off".

Troubleshooting of the EDG was performed. The fuel rack was observed to operate when control' air was removed. .The 30 psig control air which operates the pneumatic fuel control valve (FCV) was found to be at atmospheric pressure.-

During normal. starts, the FCV vents air to operate the fuel control cylinder which positions the fuel injector racks to the "on" position. Since the 30 .i psig air was not available, the' fuel control cylinder would not move. The pneumatically operated FCV.is.in series with two electrically operated emergency

-mode FCVs.- Operation of any oneuof these FCVs will vent air to operate-the

. fuel control cylinder. The event has been classified as an invalid diesel  !

generator .f ailure byf the criteria of Regulatory Guide 1.108 C.2.e(2) 'due to a malfunction of equipment.that is non-operative in the emergency operating mode. This-reportLie submitted pursuant to Technical Specifications (TS)  !

4.8.1.1.3 and'6.9.2.

The root'cause of_the event is equipment failure. A circumferential crack occurred on-the' spring. cap of the 30 psig reducer in the EDG 'A' control air system which provides air to the pneumatically operated FCV. All EDG control-air reducers have been inspected to ensure similar problems did not exist..

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NARRATIVE (Contd) ,

There han only been one failure during a valid test of EDG 'A' at Waterford 3 since the operating license was issued. The surveillance test interval required by TS table 4.8-1 has always been "at least once per 31 days" since -

issuance of the operating license. The pneumatically operated FCV is not required in the emergency mode and would not have af fected the ability of the EDG to perform its designed safety function. Therefore, this event did not present a. hazard-to plant equipment or the health and safety of the general public.

PLANT-CONTACT T.ll. Smith, Plant Engineering Superintendent, 504/464-3127.

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