Pinhole leak discovered on a Reactor Head Spray line
weld during Nuclear Steam Supply System Leak Test.
Oyster Creek Nuclear Generating Station is currently in the Shutdown Condition executing Refueling Outage 1R24, which includes Nuclear Steam Supply System (NSSS) Leak Testing, prior to startup.
At 1930 on 11/26/2012, a pinhole leak was discovered on a Reactor Head Spray Class 1 piping weld. The leak was discovered during the NSSS Leak Test, while the Reactor was in the Shutdown Condition. The leak is on a flange to piping weld on the Reactor Head Spray system upstream of the N-7B nozzle. Water was found to be weeping from the pinhole leak (approximately 2 to 3 drops per minute).
The cause is under investigation and corrective action plans are being developed.
The leak has been evaluated by Exelon and determined to meet the criteria for reporting identified in NUREG-1022: Welding or material defects in the primary coolant system that cannot be found acceptable under ASME Section XI, IWB-3600, 'Analytical Evaluation of Flaws,' or ASME Section XI, Table IWB-3410-1, 'Acceptable Standards.'
The NRC Resident Inspector has been informed.