05000334/LER-1979-007-01, /01T-0 on 790305:steam Driver Auxiliary Feedwater Pump Declared Inoperable Because 1B Steam Supply Trip Valve Would Not Close.Caused by Missing Nut & Washer on 1C Steam Generator Supply Check Valve.Nut & Washer Replaced

/01T-0 on 790305:steam Driver Auxiliary Feedwater Pump Declared Inoperable Because 1B Steam Supply Trip Valve Would Not Close.Caused by Missing Nut & Washer on 1C Steam Generator Supply Check Valve.Nut & Washer Replaced

ML19263D205
Person / Time
Site:	Beaver Valley
Issue date:	03/19/1979
From:	Werling J DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19263D203	List: 05000334/LER-1979-007, Forwards LER 79-007/01T-0 05000334/LER-1979-007-01, /01T-0 on 790305:steam Driver Auxiliary Feedwater Pump Declared Inoperable Because 1B Steam Supply Trip Valve Would Not Close.Caused by Missing Nut & Washer on 1C Steam Generator Supply Check Valve.Nut & Washer Replaced
References
LER-79-007-01T, LER-79-7-1T, NUDOCS 7903260279
Download: ML19263D205 (2)

LER-1979-007, /01T-0 on 790305:steam Driver Auxiliary Feedwater Pump Declared Inoperable Because 1B Steam Supply Trip Valve Would Not Close.Caused by Missing Nut & Washer on 1C Steam Generator Supply Check Valve.Nut & Washer Replaced

Event date:
Report date:
3341979007R01 - NRC Website

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U.S. NUCLEAR REGULATORY COMMtSSLON NRC FORM 366 (7 7M*

LICENSEE EVENT REPORT CONTROL BLOCK: l l

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8 60 61 DOCKET NUM8ER 68 69 EVENT DATE 74 75 REPORT DATE do EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h 1012l lon 3/3/79 at 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br />, the steam driven auxiliary feedwater pump was declared l

1 O a l inoperable because the 1B steam supply trip valve would not close.

The valve was l

[O 141 ldisassembled and a nut and washor were discovered in the line.

The numn was then i

10151 Ireturned t o service.

An investigation was commenced and, on 3/5/79, it was l

O 6 l determined the nut and washer came from one of the three check valves upstream of l

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the trip valve.

At 1828 hours0.0212 days <br />0.508 hours <br />0.00302 weeks <br />6.95554e-4 months <br /> on 3/5/79, the steam driven auxiliary feedwater pump [

ITITl was anain isolated and declared inoperable.

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i i Iwashers on the 1A and 1B check valves were intact. However, the nut and washer on I

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'Ithe IC steam generator steam supply check valve to the auxiliary feedwater pump were j 1 2 1i13lImissinc.

The nut and washer were replaced and the nut was pinned per vendor i 4 recommendation.

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Attachment To LER 79-007/0lT Beaver Valley Power Station oDuquesne Light Company.

Docket No. 50-334 On March 3, 1979 at 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br />, the steam driren auxiliary feedwater pump was declared inoperable because the 1B steam supply trip valve would not close. The valve was isolated and disassembled and a nut and washer were discovered in the line. The trip valve was reassembled and the pump was returned to operable condition. The plant was then returned to power.

An investigation was commenced to determine the orie,in of the components. On March 5, 1979, it was determined the nut and washer came from one of the three check valves upstream of the trip valve.

In the event of a ruptured steam line, these check valves control backflow from the operating steam generators to the ruptured line.

Operation with an inoperable check valve was in a manner less conservative than described in the SAR.

Therefore, at 1828 hours0.0212 days <br />0.508 hours <br />0.00302 weeks <br />6.95554e-4 months <br /> on March 5, the steam driven auxiliary feedwater pump was again isolated and declared inoperable.

Station shutdown was commenced at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />.

The three upstream check valves were disassembled and inspected.

The nuts and washers on the 1A and 1B check valves were intact.

However, the nut and washer on the IC steam generator steam supply check valve to the auxiliary feedwater pump were missing.

Following discussions with the valve vendor, the nut and washer were replaced and the nut was pinned per vendor recommendation.