ML20100R578

Special Rept Spr 960001:on 960211,electric Driven Fire Pump XPP0134A Declared Inoperable Due to Intermitten Tripping of Local Circuit Breaker in Panel XPN7075A on Pump Start Due to Overcurrent

ML20100R578
Person / Time
Site:	Summer
Issue date:	03/04/1996
From:	Gabe Taylor SOUTH CAROLINA ELECTRIC & GAS CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
SPR-960001, NUDOCS 9603120464
Download: ML20100R578 (2)

Text

1 South C:rolina El:ctric & Gas Comptny Giry J Tay r

• Jenkinsville, SC 29065 Nuclear Operabons (803)345-4344 SCE&G Ascnmcm March 4,1996 Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

VIRGIL C. SUMMER NUCLEAR STATION l i

DOCKET NO. 50/395 OPERATING LICENSE NO. NPF-12 SPECIAL REPORT (SPR 960001) ]

Gen' tlemen:

South Carolina Electric & Gas Company (SCE&G)is submitting this report pursuant to the administrative requirements of Fire Protection Procedure FPP-024, " Fire Suppression Systems," Enclosure 6.1.1. The Electric Driven Fire Pump, XPP0134A, was inoperable in excess of 7 days, requiring a 30 day Special Report. Prior to restoring it to operable status, the Diesel Driven Fire Pump was declared inoperable, thus requiring a 14 day Special Report. Subsequently, this report will satisfy both  !

reporting requirements. j l

On February 11,1996, the Electric Driven Fire Pump, XPP0134A, was declared i inoperable. This was due to intermittent tripping of the local circuit breaker in panel {

XPN7075A on pump start due to overcurrent. An Off-Normal Occurrence (ONO 96- 1

77) was written on February 18,1996, as a consequence of the pump being inoperable for greater than 7 days. The Diesel Driven Fire Pump remained operable 1 and provided the required fire suppression water supply.  !

The Electric Fire Pump had been tripping intermittently on start, and subsequently  ;

tagged as restricted service from February 11 to February 29. It remained i mechanically and electrically aligned to the Fire Service system to provide fire suppression water supply if necessary. This pump has experienced a history of nuisance trips during attempted starts, but has always started successfully on subsequent starts. Therefore, it has been concluded that the system was functional during the time period in question. The breaker will be replaced by March 15,1996, with a spare replacement breaker. The new breaker is supplied with a higher ,

instantaneous trip setpoint to prevent the spurious tripping problem from recurring.

l 110016 9603120464 960304 gDR ADOCK0500g5

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Document Control Desk SPR 960001/ RC-96-0057 .

Page 2 of 2 On February 21,1996, the Diesel Driven Fire Pump was being run to support  !

Surveillance Test Procedure (STP-123.0038), " Train B Service Water System Valve l Operability Test," when a leak was identified on the pressure sensing line to the l D!esel Fire Pump Discharge Relief Valve (XVR04060-FS). The diesel pump was i declared inoperable at 00:45. Immediate actions were taken to provide a backup fire j suppression water system per FPP-024, and to expedits the retum of the Diesel Fire l Pump. The Electric Fire Pump was locally started at 01:02, verified to be functioning, and ran continuously until the diesel pump was retumed to service. The pump was successfully started without the breaker tripping, and was used to establish the backup fire suppression water supply within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> required per the procedure.  ;

In addition, the Attemate Fire Service Pumps (XPP0172 and XPP0173) were aligned to the Fire Service system.  ;

l The diesel pump leak was due to a failed threaded fitting between the pump discharge relief valve strainer and a 90 degree elbow. The threaded fitting had split approximately 180 degrees circumference due to vibration induced stress at a U-bolt attachment. To preclude recurrence, the 3/8 inch fitting was replaced with a stronger 3/8 fitting and the U-bolt positioned so it would not ride on the fitting threads. The pump was placed back in service and declared operable at 06:45.

l Should you have any questions, please call Ms. Linda Martin at (803) 345-4217 at your convenience.

Very I urs, lo,r GaQ l LJM / GJT c: J. L. Skolds INPO Records Center S. D. Ebneter NRC Resident inspector ,

R.R.Mahan NSRC 1 R. J. White S. F. Fipps J.1. Zimmerman DMS (RC-96-0057) l J. B. Knotts, Jr. RTS (ONO 960085 & 960077)

Marsh & McLennan File (818.08, 818.05) l NUCLEAR EXCELLENCE - A SUMMER TRADITION!

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