05000338/FIN-2011002-03
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Finding | |
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| Title | Failure to Determine the Cause and Take Corrective Action to Preclude Repetition for Lightning Induced Reactor Trips |
| Description | A non-cited violation of 10 CFR 50, Appendix B, Criterion XVI, Corrective Action, was identified by the inspectors for the licensees failure to determine the cause of a significant condition adverse to quality (SCAQ) involving an automatic reactor trip following a lightning strike on the Unit 2 containment building. This resulted in the Unit 2 automatic reactor trip on June 16, 2010, because of the insufficient corrective action to preclude repetition. The Licensee entered this issue into the Corrective Action Program as CR 384967. The inspectors determined that the failure to determine the cause of a SCAQ was a performance deficiency (PD). The inspectors reviewed IMC 0612, Appendix B and determined the PD was more than minor because, if left uncorrected, it has the potential to lead to a more significant safety concern in that failing to identify the cause of SCAQs and thus failing to take corrective action to preclude repetition could result in additional initiating events or impacts on mitigating systems. In addition, the inspectors determined that it adversely impacted the Initiating Events cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown as well as power operations, specifically the attribute of Protection Against External Factors in that the removal of the Overtemperature Delta T lag function removed protection from lightning strikes on the reactor protection system. The inspectors reviewed IMC 0609, Attachment 4 and determined that the finding was of very low safety significance, or Green, because it did not contribute to both the likelihood of a reactor trip and the likelihood that mitigation equipment or functions will not be available. The cause of this finding involved the cross-cutting area of problem identification and resolution, the component of operating experience, and the aspect of evaluation of identified problems, P.1(c) because the licensee failed to thoroughly evaluate the cause of the 2005 reactor trip and conduct effectiveness reviews of corrective actions to ensure the problems are resolved. |
| Site: | North Anna  |
|---|---|
| Report | IR 05000338/2011002 Section 4OA3 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | J Reece G Mccoy R Clagg C Sanders |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - North Anna - IR 05000338/2011002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (North Anna) @ 2011Q1
Self-Identified List (North Anna)
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