05000458/FIN-2012002-03
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Finding | |
|---|---|
| Title | Failure to Verify Assumptions used in Standby Equipment Room Temperature Analysis |
| Description | The inspectors identified a non-cited violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, because, prior to February 7, 2012, the licensee did not verify that assumptions used in confirming that the safety-related battery inverter rooms would remain below their design basis temperature limits during a design basis event agreed with the as-built condition of the plant. This finding was entered into the licensees corrective action program as Condition Report CR-RBS-2012-01046. The inspectors determined that the failure to verify that design documents match the actual configuration of the plant is a performance deficiency. The finding was more than minor because it adversely affects the Mitigating Systems Cornerstone objective of equipment performance to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the licensee had not verified assumptions that ensure the standby switchgear room air conditioning system would reliably maintain the standby equipment rooms below the design temperature limits. Using Inspection Manual Chapter 0609, Attachment 4, 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, nor actual loss of safety function of a single train, and it did not screen as potentially risk significant due to a seismic, flooding, or severe weather initiating event. The inspectors determined that this issue has a cross-cutting aspect in the area of human performance decision-making regarding nonconservative assumptions. When the licensee conducted the flow balance test, they assumed that measuring air inflow alone was sufficient, but did not check that the doors gaps were allowing a sufficient amount of warm air to exit standby equipment rooms and be circulated back to the general areas |
| Site: | River Bend  |
|---|---|
| Report | IR 05000458/2012002 Section 1R17 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.17 |
| Inspectors (proximate) | W Sifre R Hagar G Larkin V Gaddy S Makor D Reinert C Alldredge L Carson S Garchow A Barrett |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - River Bend - IR 05000458/2012002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (River Bend) @ 2012Q1
Self-Identified List (River Bend)
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