05000445/FIN-2011002-03
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Finding | |
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| Title | Failure to Identify and Correct Safety Injection Reset Malfunction |
| Description | The inspectors identified a non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action for the failure of the licensee to promptly identify and correct a safety injection reset malfunction caused by a design error. As a result, this malfunction could have delayed the termination of an inadvertent safety injection, a time critical action for avoiding the reactor coolant system reaching water solid conditions. The licensee entered the finding into the corrective action program as Condition Report CR-2011-003476. The finding was more than minor because it was associated with the design control attribute of the initiating events cornerstone and adversely affected the cornerstone objective, in that, the finding increased the likelihood of the reactor coolant system reaching water solid conditions during an inadvertent safety injection. Using IMC 0609, Attachment 4, Phase 1 - Initial Screening and Characterization of Findings, the finding was determined to require a Phase 2 analysis because, as a potential loss of coolant accident initiator, the worst case degradation of ineffective operator actions would result in exceeding reactor coolant system leakage limits. The inspectors determined that a Phase 2 analysis was not applicable to the performance deficiency. A senior reactor analyst reviewed the licensees risk estimate and determined that no further analysis was needed to conclude that the conditional risk of an inadvertent safety injection was very low. The licensees analysis did not consider the risk related to a steam line break inside containment where the recovery would be complicated by multiple valve manipulations needed to restore reactor coolant pump thermal barrier cooling before securing the charging pumps. However, the low frequency of a sufficiently-sized steam line break inside containment combined with the low probability, two percent, that the safety injection could not be reset reduced the scenario of concern to a frequency of less than 1.0E-6/yr. Therefore, the analyst concluded that the performance deficiency was of very low safety significance. The finding has a problem identification and resolution crosscutting aspect associated with the corrective action program because the licensee failed to thoroughly evaluate the problem (P.1(c)). |
| Site: | Comanche Peak  |
|---|---|
| Report | IR 05000445/2011002 Section 1R15 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | NCV: Green |
| cornerstone | Initiating Events, Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | D Stearns L Carson W Walker B Tindell J Kramer |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Comanche Peak - IR 05000445/2011002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Comanche Peak) @ 2011Q1
Self-Identified List (Comanche Peak)
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