05000336/FIN-2011003-01
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Finding | |
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| Title | Failure to Take Timely Corrective Actions for De-alloying of Aluminum Bronze Service Water Valves |
| Description | The inspectors identified a Green NCV of 10 CFR 50, Appendix B, Criterion XVl, corrective Action, for Dominion\'s failure to take timely corrective actions for a condition adverse to quality involving the degradation and subsequent through-wall leakage of Unit 3 service water valves 3SWP.V699 (3HVQ.ACUS1B Bypass Valve), 3SWP.VO18 (3HVQ.ACUS2B Unit Cooler Inlet Valve), and 3SWP*V696 (3HVQ.ACUS2B Unit Cooler Outlet Valve). Specifically, Dominion did not adequately implement a schedule for prioritizing and completing corrective actions on affected aluminum bronze components, which were known to be susceptible to de-alloying, commensurate with the safety significance of the degraded condition. As a result, through-wall leaks developed on these valves and resulted in unplanned loss of operability and additional unavailability of the safety-related support systems for the \'B\' train of containment recirculation spray pumps. Dominion took immediate corrective action to replace the three leaking service water (SW) valves (CR428785). The inspectors determined that this issue was more than minor because it is similar to the more than minor example, 4.F, of IMC 0612, Appendix E, Examples of Minor lssues. Specifically, the degraded condition caused a loss of operability of the \'B\' train of the containment iecirculation spray system. Additionally, the finding was more than minor because it is associated with the Equipment Performance attribute of the Mitigating Systems cornerstone, and adversely affected the cornerstone objective of ensuring-the availability of systems that respond to initiating events to prevent undesirable consequences. ln accordance with NRC lnspection Manual Chapter 0609, Attachment 4, Phase 1 - Initial Screening and Characterization of Findings, a Phase 1 SDP screening was performed and determined the finding was of very low safety significance (Green) because it was not a design or qualification deficiency, did not represent an actual loss of system safety function of a single train for greater than its Technical Specification allowed outage time, and did not screen as potentially risk significant due to a seismic, flooding, or severe weather initiating event. The finding had a cross-cutting aspect in the Problem ldentification and Resolution cross-cutting area, Corrective Action Program component, because Dominion did not ensure that issues potentially impacting nuclear safety were corrected in a timely manner commensurate with their safety significance. Specifically, Dominion failed to adequately implement corrective actions to address a known de-alloying issue with SW valves before ihe condition led to the unplanned loss of operability and additional unavailability of the safety-related support systems for the \'B\' train of containment recirculation spray pumps. |
| Site: | Millstone  |
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| Report | IR 05000336/2011003 Section 1R15 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | T Moslak D Jackson M Modes B Haagensen J Krafty S Shaffer |
| CCA | P.3, Resolution |
| INPO aspect | PI.3 |
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Finding - Millstone - IR 05000336/2011003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Millstone) @ 2011Q2
Self-Identified List (Millstone)
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