05000336/FIN-2011004-01
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Finding | |
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| Title | Failure to Electrically Isolate Dissimilar Metal Flanged Joint Leads to Forced Shutdown Due to Service Water Leak |
| Description | A self-revealing NCV of 10 CFR 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, was identified for Dominion\\\'s failure to properly electrically isolate service water (SW) flanged joints of dissimilar metals. This caused a more rapid corrosion rate when a defect occurred in the lining of the carbon steel pipe and eventually led to a SW leak. On September 3, 2011, Dominion was forced to shut down Unit 2 when the spool leaked in excess of the limit allowed in authorized relief from American Society of Mechanical Engineers (ASME) code requirements. Dominion repaired the spool and electrically isolated the flanged joint. Dominion entered this issue into their corrective action program (CAP) CR441302. The finding is more than minor because it is associated with the Human Performance attribute of the Mitigating Systems cornerstone and affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The finding was of very low safety significance (Green) because the finding was not a design or qualification deficiency that did not result in loss of operability, did not represent an actual loss of system safety function, did not represent an actual loss of safety function of a single train for greater than its technical specification (TS) allowed outage time, did not represent an actual loss of safety function of one or more non-technical specification trains of equipment designated as risk significant per 10 CFR 50.65, and did not screen as risk significant due to a seismic, flooding, or severe weather initiating event. The inspectors determined that this finding had a cross-cutting aspect in the Human Performance cross-cutting area, Work Practices component, because Dominion personnel proceeded in the face of uncertainty andlor unexpected circumstances when they had difficulty installing the isolating sleeves in the flanged joint. |
| Site: | Millstone  |
|---|---|
| Report | IR 05000336/2011004 Section 1R20 |
| Date counted | Sep 30, 2011 (2011Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.2 |
| Inspectors (proximate) | T Moslak D Silk B Fuller N Mcnamara B Haagensen J Krafty S Shaffer R Bellamy C Crisden |
| CCA | H.12, Avoid Complacency |
| INPO aspect | QA.4 |
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Finding - Millstone - IR 05000336/2011004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Millstone) @ 2011Q3
Self-Identified List (Millstone)
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