Finding | |
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| Title | |
| Description | A self-revealing, Green, NCV of 10 CFR 50 Appendix B, Criterion XVI, Corrective Action, was identified because Entergy did not promptly correct an adverse condition resulting in the failure of the B uninterruptible power supply (UPS) motor generator (MG) set direct current (DC) tachometer coupling. Specifically, Entergy personnel did not promptly replace or verify the physical condition of the B tachometer coupling when it was known that it was aged and susceptible to age-related failure. Entergys corrective actions included replacing the B tachometer coupling, establishing a 12 year preventive maintenance replacement frequency, and initiating CR-VTY-2011-03686, CR-VTY-2011- 03744, CR-VTY-2011-05335, CR-VTY-2011-05337, and CR-VTY-2012-01096. The inspectors determined that the issue was more than minor because it is associated with the Equipment Performance attribute of the Mitigating Systems cornerstone and affected the cornerstone objective to ensure the availability and reliability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Specifically, the B UPS MG set failed in service, affecting the overall system redundancy and reliability, and resulted in 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> of unplanned unavailability. The inspectors determined the significance of the finding using IMC 0609.04, Phase 1 Initial Screening and Characterization of Findings. The finding was determined to be of very low safety significance (Green) because it did not represent a loss of system safety function, a loss of safety function of a single train for greater than its technical specification (TS) allowed outage time (UPS-1B), and did not screen as potentially risk significant due to external initiating events. The inspectors determined that the finding had a cross-cutting aspect in the Human Performance cross-cutting area, Decision-Making component, because Entergy personnel did not use conservative assumptions in decision making and did not adopt a requirement to demonstrate that the proposed action to delay the coupling replacement until June 2012 was safe. |
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
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| Report | IR 05000271/2012002 Section 1R12 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | S Rutenkroger R Bellamy E Burket S Rich E Keighley K Dunham |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Vermont Yankee - IR 05000271/2012002 | |||||||||||||||||||||||||
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Finding List (Vermont Yankee) @ 2012Q1
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