05000334/FIN-2010005-06
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Finding | |
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| Title | 270 Degree Circumferential Flaw Found on Residual Heat Removal System Drain Valve Socket Weld |
| Description | On October 2,2010, while Beaver Valley, Unit 1 was shut down in Mode 5 (cold shutdown) for a refueling outage, an active boric acid leak was identified on a drain valve (1 RH-200) located on the common suction piping for the Residual Heat Removal (RHR) system. ApprOXimately five hours after the initial identification of the active leak and entry into Mode 5, a nondestructive examination (NDE) was performed on the valve and its associated piping. A circumferential crack of 270 degrees in length with water seeping from the toe of the weld was discovered and both trains of RHR were declared inoperable. Since the adverse condition was identified prior to the completion of the NDE and no action was immediately taken as required by TS 3.4.7 for no required RHR trains operable while in Mode 5 operation, the licensee inadvertently entered a condition prohibited by TS 3.4.7. When the licensee determined that both trains of RHR were inoperable, they evaluated the issue for reportability and appropriately issued LER 50-334/2010-002, 270 Degree Circumferential Flaw Found on Residual Heat Removal System Drain Valve Socket Weld, dated November 29,2010. This LER reported that Beaver Valley, Unit 1 had been in a condition which was prohibited by TS 3.4.7.C, which requires immediate action if both trains of RHR are inoperable while in Mode 5 operations. The issue is considered within the traditional enforcement process because there was no performance deficiency identified and Inspection Manual Chapter (IMC) 0612, Appendix B, Issue Screening directs disposition of this issue in accordance with the Enforcement Policy. The inspectors ysed the Enforcement Policy, Section 6.1 - Reactor Operations, to evaluate the significance of this violation. The inspectors concluded that the violation is more than minor and best characterized as Severity Level IV (very low safety significance) because it is similar to Enforcement Policy Section 6.1, example d.1. Additionally, the inspectors assessed the risk associated with the issue by using (MC 0609, Appendix G, Shutdown Operations Significance Determination Process. The inspectors screened the issue, and evaluated it using Checklist 2 of IMC 0609, Appendix G, Attachment 1. Throug out the duration of the event, the secondary side water level of at least two steam generators sufficient for decay heat removal (including necessary support systems) were available. As a result, this issue would screen as very low safety significance (Green). Because it has been determined that it was not reasonable for the licensee to be able to foresee and prevent the weld crack, or to have made the RHR inoperability decision at an earlier time, and as such no performance deficiency exists, the NRC has decided to exercise enforcement discretion in accordance with Section 3.5 of the NRC Enforcement Policy and refrain from issuing enforcement action for the violation of TS (EA-11-004). Further, because licensee actions did not contribute to this violation, it will not be considered in the assessment process or the NRC's Action Matrix. |
| Site: | Beaver Valley |
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| Report | IR 05000334/2010005 Section 4OA3 |
| Date counted | Dec 31, 2010 (2010Q4) |
| Type: | Violation: Severity level Enforcement Discretion |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | D Werkheiser E Bonney P Kaufman R Bellamy T Moslak |
| INPO aspect | |
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Finding - Beaver Valley - IR 05000334/2010005 | |||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Beaver Valley) @ 2010Q4
Self-Identified List (Beaver Valley)
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