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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 48537 | 27 November 2012 00:30:00 | 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | Degraded Condition Due to Pinhole Leak in Reactor Head Spray Line | 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. | ||
| ENS 48491 | 7 November 2012 17:40:00 | 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | Liquid Penetrant Surface Indications Found on Control Rod Drive Return Nozzle Safe End to Pipe Weld | Oyster Creek Nuclear Generating Station is currently in Cold Shutdown executing Refueling Outage 1R24, which includes in-service inspections. At 1240 EST, General Electric notified Oyster Creek Management of surface indications that were detected by dye penetrant testing. The indications are in the adjacent base material area of the System Pressure Boundary weld. The indications are located Top Dead Center (TDC) of the 3 inch pipe. Indication #1 is upstream 0.7 inches away from the weld toe, the indication is 1.5" long. Indication #2 is downstream 0.2 inches away from the weld toe, the indication is 2.5" long. The depth of the indications are unknown at this time. Initial investigation revealed that there was no moisture or leakage found in the area of the indications. Further investigation is in progress to better characterize the indications. The cause is under investigation and corrective action plans are being developed. The surface defects have 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. | Control Rod |