05000416/FIN-2012008-03
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Finding | |
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| Title | Failure to Obtain NRC Approval for a Change to Credible Passive Failures in the Standby Service Water System |
| Description | The team identified a Severity Level IV non-cited violation of 10 CFR 50.59, Changes, Tests and Experiments which states, in part, that a licensee shall obtain a license amendment pursuant to Section 50.90 prior to implementing a proposed change, test, or experiment if this activity would; result in more than a minimal increase in the likelihood of occurrence of a malfunction of a structure, system, or component important to safety previously evaluated in the final safety analysis report (as updated). Specifically, on August 18, 1987, the licensee implemented a change to the updated safety analysis report which limited credible passive failures in the standby service water system to pump and valve sea! leakage without obtaining a license amendment. This finding was entered into the licensee\'s corrective action program as Condition Report CR-GGN-2012-09267. The team determined that the licensee\'s failure to receive prior NRC approval for changes in licensed activities regarding single passive failure criteria for the standby service water system was a performance deficiency. The performance deficiency was evaluated using traditional enforcement because the finding had the ability to impact the regulatory process. The performance deficiency was more than minor because there was a reasonable likelihood that the change would require NRC review and approval prior to implementation. In accordance with the NRC Enforcement Manual, risk insights from the Inspection Manual Chapter 0609, Significance Determination Process, are used in determining the significance of 10 CFR 50.59 violations. Using the Inspection Manual Chapter 0609, A, Significance Determination Process for Findings At-Power, the team determined that the finding represented a loss of safety function in that the standby service water system could not meet its 30-day mission time to provide decay heat removal. Therefore, a Detailed Risk Evaluation was necessary. In accordance with Manual Chapter 0609, Appendix A, Section 6, Detailed Risk Evaluation, the senior reactor analyst evaluated the risk of the degraded condition that resulted from the finding. According to the Risk Assessment of Operational Events Handbook, Volume 1-lnternal Events, Section 4.1, Mission Time Modeling, in most events, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is sufficient time to bring numerous resources to bear on core cooling. In some events, the choice is conservative and the analysis results are overestimates. Additionally, the analyst determined that Section 4.2 on increasing mission time was not applicable to the subject finding because the decrease in standby service water system water inventory would be obvious and there would be days to respond with makeup sources. Therefore, the analyst determined that the finding was of very low safety significance (Green) because, although the standby service water system could not provide 30 days of decay heat removal without operator action to provide makeup water to the system, it would have been able to complete its 24-hour risk significant mission time. Since the finding had very low safety significance, the finding was determined to be Severity Level IV, in accordance \\, Iith the NRC Enforcement Policy. The finding does not have a crosscutting aspect because the most significant contributor to the finding does not reflect current licensee performance. |
| Site: | Grand Gulf  |
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| Report | IR 05000416/2012008 Section 1R21 |
| Date counted | Sep 30, 2012 (2012Q3) |
| Type: | TEV: Severity level IV |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | I Anchondo N Okonkwo J Braisted |
| INPO aspect | |
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Finding - Grand Gulf - IR 05000416/2012008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Grand Gulf) @ 2012Q3
Self-Identified List (Grand Gulf)
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