Pilgrim’s Junk Safety Valves

Pilgrim’s Junk Safety Valves

PILGRIM NUCLEAR POWER STATION - NRC INTEGRATED INSPECTION

REPORT 05000293/2014002

Closed) LER 05000293/2013-002-00 and LER 05000293/2013-002-01: SRV-3B Safety

Relief Valve Inoperable Due to Leakage and Setpoint Drift

The inspectors reviewed Entergy’s actions and reportability criteria associated with LERs

05000293/2013-002-00 and 05000293/2013-002-01, which is addressed in CR-PNP-
2013-0378. On January 20, 3013, with the reactor at 100 percent power, Pilgrim
operators declared safety relief valve (SRV)-3B inoperable and entered TS 3.6.D.2
requiring an orderly reactor shutdown. SRV-3B had been declared inoperable in
occordance with PNPS procedures which state an SRV is inoperable if the first stage
pilot thermocouple temperature is 35 degrees Fahrenheit below its baseline
temperature. The cause of the SRV leakage was that the natural frequency of the pilot
assembly was close to the resonant frequency of the valve assembly when installed on
the PNPS main steam line, as well as wear and looseness of parts in the main stage of
SRV-3B. Corrective actions that have been completed include the replacement of the
SRV-3B pilot with a refurbished and tested pilot, and to revise station procedures to
reduce reactor power and pressure to stop leakage if it were to occur. Additional
planned corrective actions are to adjust pilot setpoints within the allowed band to
minimize leakage potential, to replace pilots that contain bellows springs of the same
material and heat treatment, and to order new pilot assemblies that have been designed
to raise the natural frequency of the pilot. The inspectors did not identify any new issues
during the review of these LERs. These LERs are closed.