05000482/FIN-2011002-03
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Finding | |
|---|---|
| Title | Failure to Monitor the Performance of Nonsafety-Related Systems and Components Used in the Plant Emergency Operating Procedures under 10 CFR 50.65 Programs |
| Description | The inspectors identified a noncited violation of 10 CFR 50.65(a)(1) with three examples involving the failure to monitor the performance of stand by nonsafety-related systems and components that exceeded performance criteria against goals. First, the inspectors identified that the licensee failed to monitor the turbine-driven main feedwater pumps against their standby restart function to fill the steam generators in emergency operating procedures. Failures of the two turbine-driven main feedwater pumps occurred which could have prevented fulfillment of this function. Second, the inspectors identified that the licensee failed to evaluate reactor trips caused by the main feedwater system against the systems plant level monitoring criteria. Third, the inspectors identified that the licensee failed to monitor the instrument air compressor system against its emergency operating procedure function to restart and provide compressed air. Several instrument air compressor trips have occurred in the last 18 months which could have prevented fulfillment of this function. The licensee entered this issue in the corrective action program and will develop corrective actions as part of Condition Report 36600. The failure to establish performance monitoring goals commensurate with the mitigating safety function specified in the emergency operating procedures and the plant level criteria is a performance deficiency. The performance deficiency is more than minor, and therefore a finding, because it impacts equipment performance attribute of the Mitigating Systems Cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Using the NRC Inspection Manual Chapter 0609, Attachment 0609.04, Phase 1 Initial Screening and Characterization of Findings, the finding screened to a Phase 2 significance determination because it involved a potential loss of safety function of the main feedwater system and failure of the instrument air system. A Region IV senior reactor analyst performed a Phase 2 significance determination and using the pre-solved worksheet from the Risk Informed Inspection Notebook for the Wolf Creek, Revision 2.01a; however, the presolved worksheet did not include the simultaneous failure of multiple components in different systems. Therefore, the senior reactor analyst performed a bounding Phase 3 significance determination using Appendix M of Inspection Manual Chapter 0609, Significance Determination Process Using Qualitative Criteria, Section 4.1.2. The analyst determined that the finding was of very low safety significance (Green). The bounding change to the core damage frequency was approximately 8 E-7/year. The relatively low risk worth of the instrument air system at Wolf Creek helped to mitigate the significance. To evaluate the change to the large early release frequency (LERF), the analyst used Inspection Manual Chapter 0609, Appendix H, Containment Integrity Significance Determination Process. The finding screened as having very low safety significance for LERF because it did not affect the intersystem loss of coolant accident or steam generator tube rupture categories. The inspectors determined that the finding had a crosscutting aspect in the area of problem identification and resolution. Specifically, when Wolf Creek evaluated exceeding the plant level monitoring criteria for reactor trips, their analysis did not identify that failures within the main feedwater system were the cause of four of the six reactor trips, and did not place the affected system function in a(1) monitoring P.1(c) (Section 1R12). |
| Site: | Wolf Creek  |
|---|---|
| Report | IR 05000482/2011002 Section 1R12 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | G Guerra C Smith L Carson G Miller B Tindell C Long C Peabody A Fairbanks D Reinert C Alldredge |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Wolf Creek - IR 05000482/2011002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Wolf Creek) @ 2011Q1
Self-Identified List (Wolf Creek)
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