05000263/FIN-2014008-01
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Finding | |
|---|---|
| Title | Shorting Switch Modification Failed to ensure Drywell Spray Valves would not Spuriously Open |
| Description | The inspectors identified a finding of very-low-safety significance and associated NCV of 10 CFR Part 50, Appendix R, Section III.G.2 for the licensees failure to ensure that safe shutdown (SSD) equipment were not susceptible to fire induced failures. Specifically, the licensee failed to ensure that the Drywell Spray Motor Operated Valves MO-2020 and MO-2021 would not spuriously open due to fire induced failures (i.e., open circuit and hot shorts) when they installed shorting switch modifications for these valves. The licensee entered the issue into their Corrective Action Program and established hourly fire tours in all affected fire areas. The performance deficiency was determined to be more than minor because the multiple spurious operations of the drywell spray valves could affect safe shutdown of the plant in the event of fire. The finding affected the Mitigating Systems cornerstone. These valves were required to stay in their closed position during a fire event to ensure adequate net positive suction head (NPSH) for safe shutdown pumps. Fire induced circuit failures (i.e., open circuits and hot shorts) on their control cables could result in these valves spuriously opening. The finding represented a low degradation; and therefore, the inspectors determined that the finding screened as having very-low-safety significance (Green) in Task 1.3.1 of IMC 0609, Appendix F. The inspectors determined that the finding had a cross-cutting aspect in the area of Problem Identification and Resolution because the licensee did not thoroughly evaluate issues to ensure that resolutions address causes and extent of conditions commensurate with their safety significance. Specifically, the licensees evaluation incorrectly concluded that the shorting switch modification would preclude multiple spurious operations of the Drywell Spray valves. |
| Site: | Monticello  |
|---|---|
| Report | IR 05000263/2014008 Section 1R05 |
| Date counted | Mar 31, 2014 (2014Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | A Dahbur D Oliver R Daley R Winter |
| Violation of: | 10 CFR 50 Appendix R |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Monticello - IR 05000263/2014008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Monticello) @ 2014Q1
Self-Identified List (Monticello)
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