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| Entered date | Event description | |
|---|---|---|
| ENS 45719 | 23 February 2010 16:58:00 | On 2/22/10, we determined that there was pressure boundary leakage on Unit 2 from the leak off line associated with a pressurizer spray valve (2-RC-220). The source of leakage associated with a boron deposit discovered earlier on 2/18/10. The boron deposit formed based on a leak in a Class 1 manual valve packing leak-off line. The leak location was determined to be in the packing leak-off pipe fillet weld to the stem retaining structure of the valve in the packing gland area. The valve (2-RC-220) is a Class 1 pressure boundary. The packing leak-off line is considered an auxiliary connection in the stem retaining structure of the valve. At this time, we believe the most probable cause of the 2-RC-220 leak-off line socket weld leak was based on two factors, a small pore in the original socket weld metal and the location of a valve tag attachment wire. The leak location coincided with the location where a valve tag attachment wire laid across the weld. It is possible this wire, vibrating against the weld, opened up a subsurface pore in the weld metal which began to leak sometime after startup from the 2009 RFO (Refueling Outage) (March 2009). Since the failure may have occurred due to a material problem that resulted in abnormal degradation of a principal safety barrier (i.e., it is necessary to take corrective actions to restore the weld's integrity), this event is reportable pursuant to 10 CFR 50.72(b)(3)(ii)(A). The valve was overhauled in the 2009 RFO and subsequently passed VT-2 inspection. The overhaul did not include any welding on the affected joint. Unit 2 is in Mode 5 to allow repairs to be made to this weld. The licensee will notify the NRC Resident Inspector. |
| ENS 45366 | 20 September 2009 05:50:00 | At 0130 the 800 MHZ radio (control) system failed to the 'fail soft' mode rendering all (73) emergency notification sirens inoperable. At 0305 courtesy call notifications were made to the county control centers (Calvert, Dorchester, St. Mary's and MEMA). The backup system was placed in service and 800 MHZ radio and ENS sirens restored to operable status at 0526 9/20/09." Maintenance work to restore the primary system will occur today. The licensee notified the NRC Resident Inspector. |