ML20011F350

Special Rept SR-90-002-00:on 900128,emergency Diesel Generator a Declared Inoperable to Perform Automatic Synchronization Test.Caused by Thick Oil Forming in Low Turbocharge Lube Oil Pressure Sensing Device.Device Cleaned

ML20011F350
Person / Time
Site:	Waterford
Issue date:	02/23/1990
From:	Mcgaha J LOUISIANA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
SR-90-002-00, SR-90-2, W3A90-0114, W3A90-114, NUDOCS 9003050183
Download: ML20011F350 (4)

Text

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POWER & LIGHT WATERFORD 3 SES

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W3A90-0114 l A4.05.

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February 23,.1990  ;

U.S. Nuclear Regulatory Commission- 1 ATTENTION: Document Control Desk Washington, D.C. 20555  ;

SUBJECT:

'Waterford 3 SES Docket No. 50-382 .

License No.~NPF-38 I Reporting of Special Report Attached is Special Report Number SR-90-002-00 for Waterford~ Steam

' Electric Station Unit 3. This Special Report.is submitted per~ ,

10CFR50.36(c)(2) and Technical Specifications 4.8.1.1.3 and 6.9.2.

s Very truly yours, 0.R. McGaha

' Plant Manager - Nuclear i JRM/JEF/rk .

~ Attachment

cc Messrs. R.D. Martin J.T. Whcolock - INPO Records Center E.L. Blake W.M'. Stevenson

• D.L. Wigginton NRC Resident Inspectors r

9003050183 900223 D PDR S

ADOCK 050003G2 PDC P

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"AN EQUAL OPPORTUNITY NMPLOYER"

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p S SPECIAL REPORT

[- SR-90-002-00 g,_ invalid Failure of Emergency Diese1' Generator A ,

'Due to. Spurious Operation of A Trip That is Bypassed in the Emergency Mode INTRODUCTION At 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on January 28, 1990, Waterford Steam Electric Station Unit 3 was shutdown, in Mode S, when Emergency Diesel Generator (EDG) A was declared inoperable to perform an automatic synchronization test. EDG A tripped on low turbocharger lube oil pressure when it was started for the test. This-event has been classified as an invalid failure.

The root cause of the event is thick oil forming in the low turbocharger lube oil pressure shutdown sensing device. During engine startup, the low turbocharger lube oil pressure shutdown is blocked to allow time for oil pressure to buildup and reset the oil pressure sensing device. The viscous oil prevented resetting the trip before the starting sequence timed out. The sensing device was removed, cicaned, and recalibrated. EDG A engine low lube oil shutdown sensing device and EDG B low turbocharger lube oil shutdown sensing device were inspected to verify a similar condition did not exist.. The .

low turbocharger lube oil pressure trip is bypassed in the emergency mode and would not have affected the ability of the EDG to perform its designed safety function. Therefore, there was no hazard to plant equipment or the health and safety of the general public, h

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J At 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on January 28, 1990, Waterford Steam Electric Station UnitD3 was 'l

[  ! shutdown in: Mode 5. when Emergency Diesel Generator'.(EDC) A was declared l Linoperableito perform Special Test Procedure (STP) '251569 "EDG Automatic ,

' Synchronization Test." EDG A tripped on low turbocharger-lube oil pressure approximately_ ten-seconds after it was started'for this STP.- Operations l

. personnel noted_that.the local turbocharger lube oil pressure gauge' indicated-

, .the~normally expected operating value when the trip. occurred.- The event has

been classified as ~an invalid diesel generator f ailure by the criteria of l

.y l Regulatory Guide 1.108 C.2.e(2) due to a malfunction of equipment that_is non-operative in the emergency operating mode. This report is submitted pursuant--

" to Technical-Specification (TS) 4.8.1.1.3 and 6.9.2.

Troubleshooting of the EDG was performed. The turbocharger low pressure shutdown sensing device was found to be in calibration tolerances but responded I slower than expected. Thick oil was found inside the sensing device. The device was cleaned out and recalibrated. EDG A engine low lube oil shutdown -

sensing device and EDG' B. low turbocharger ~1ube oil shutdown sensing device vere inspected to verify a similar condition did not exist. After starting and 1 loading EDG A in accordance with operating procedure (0P) 009-002 " Emergency -I Diesel Generator" at 1507 hours0.0174 days <br />0.419 hours <br />0.00249 weeks <br />5.734135e-4 months <br /> on January 30, 1990, EDG A was declared operabic.

The. root cause of the event was thick' oil forming in the low turbocharger lube  :

oil pressure shutdown sensing device. During engine startup, the low turbocharger l lube oil pressure shutdown is locked out to allow time-for the oil pressure to-

-buildup and reset the low pressure sensing device. The viscous oil prevented resetting the trip before the starting sequence timed out. After the oil was cleaned out, the sensing device responded as expected. Because a similar

_ problem was not found in the other low lube oil pressure shutdown sensing devices inspected, this is believed to be an isolated case. The calibration

. preventive maintenance task of the lube oil pressure trips is being modified to

.-include clean and inspect the lube oil pressure sensing devices every eighteen

. months to prevent-viscous oil from forming in the lube oil pressure sensing

' devices.

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.'There has only[beenione failure during a valid

test of EDG A_at Waterford 3# <

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, 4 Laince'theLoperatingl license was issued. The' surveillance test interval required 1

by TS Table 4.8-1 has alway's been '.'at least- i once; per 31- days" since ' issuance ' of1

(; the9 operating license.1The low turbocharger lube oil pressure ' trip 'is bypaaeed j

[@ in thefemergency' mode _and would-not affect.the ability-lofJthe:EDG!to perform l ,

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? 4 its !safetiyf f' unction; Therefore, this event did not present 'aLhazardt to plant -

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1 Jequipment'or:the: health and safety of the. general'public.

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4 f5 ,  ;" : PLANT' CONTACT- -

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r; 1 T.H.-Smith . Plant Engineering Superintendent, 504/464-3127.- [i

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