Facility Affected:
Xcel Energy - Prairie Island Nuclear Generating Plant (PINGP).
Component Affected:
OP Engine- Air Start Piping Assemble (p/n 11879060*00) shipped after October 23, 2012.
Supplier:
Fairbanks Morse Engine, 701 White Ave., Beloit, WI 53511.
Nature of Defect:
During a routine emergency diesel generator (EDG) test on 1/28/2013, one of the two redundant air start systems was isolated from the other and the single air start system failed to start the EDG due to the foreign material in the solenoid valve. The foreign material removed from the solenoid valve during failure analysis appears to be liquid pipe sealant used to seal threaded pipe joints during assembly.
Safety Hazard Which Could Be Created By Such Defect:
Foreign material within both of the redundant air start piping systems could become lodged in both of the solenoid valves. Simultaneous failure of the two solenoid valves would prevent the emergency diesel generator from starting.
Corrective Action:
PINGP has completed disassembly and cleaning of both piping systems to ensure no foreign material remains within the piping system.
FM will create a workmanship standard for pipe sealing,
hydrostatic testing, and pressure testing that will include a
foreign material exclusion program to ensure cleanliness of assemblies. This will be completed by June 30, 2013. FM has issued Corrective Action No. 2609 in its Quality Assurance Program.