05000286/FIN-2012002-04
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Finding | |
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| Title | Inadequate Corrective Actions Associated with Degraded Motor Cutoff Switches on 480 Volt Breakers |
| Description | The inspectors identified an NCV of very low safety significance, of 10 CFR 50, Appendix B, Criterion XVl, "Corrective Actions," because Entergy personnel did not promptly identify and correct, a condition adverse to quality associated with degraded motor cutoff (MCO) switches utilized on Westinghouse DS-style 480 Volt breakers. In particular, the MCO switches were related to breakers that did not operate on February 18, 2004, for a breaker that was intended for use for MCC-36D and on November 11, 2010, for the 32 containment spray (CS) pump. The inspectors determined that Entergy did not identify, correct, and replace in a timely manner, degraded, original-style, Westinghouse MCO switches that exist in DS-style 480V breakers at Unit 3. These switches exhibited contact degradation and other internal failure mechanisms that resulted in intermittent operation, and caused safety-related breaker malfunctions. This inadequate evaluation of MCO switch failures and development of appropriate corrective actions resulted in the subsequent failure on August 19, 2011, of the 32 component cooling water (CCW) pump circuit breaker. Also, Technical Specification (TS) 3.6.6.A, requires that with one CS train inoperable, the train must be restored to operable with 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or if the required action and associated completion time are not met, be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br />. Contrary to the above, between August 18, 2010 and November 12, 2010, the 32 CS pump was inoperable for approximately 86 days without the pump being returned to operable status, or the start of a reactor shutdown. Additionally, during this same period of inoperability, the redundant 31 CS pump was inoperable on October 17th and 25th, which is considered a TS-prohibited condition because TS 3.6.6.F, required immediate entry into TS 3.0.3 and subsequent shutdown to Mode 3 within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> with two CS trains inoperable. Also, because during the same period of inoperability for the 32 CS pump in 2010, the 33 emergency diesel generator (EDG) was inoperable on September 14-15th, October 5-6th, and November 4th, actions to meet TS 3.8.1.b were not met, due to the inoperability of redundant components supported by the EDG, and therefore is also considered a TS-prohibited condition. Corrective actions included the LER submittal, performance of a higher-tier apparent cause evaluation to determine the cause of the breaker failures, revisions to applicable preventive maintenance procedures to ensure future breaker maintenance activities include (1) criteria for installation of new, enhanced motor cutoff switches, where applicable, and (2) expanded resistance checks are performed to verify switch reliability and satisfactory operation. The inspectors determined that not identifying and correcting a condition adverse to quality associated with the 32 CCW breaker failure to close on demand, in August 2011 was a performance deficiency. The inspectors concluded the problem was within Entergys ability to foresee and correct. Specifically, available information from previous internal failures, external industry failures, and vendor information, should have been utilized to identify the deficient internal contacts of the old-style MCO switches and inform the identification and implementation of appropriate corrective actions following the 32 CS pump circuit breaker MCO switch malfunction in November 2010. The inspectors determined that if appropriate corrective actions had been identified and implemented, they could have prevented the subsequent failure of the 480V breaker during the August 2011, Loss of 138kV off-site power event associated with the 32 CCW pump because of its MCO switch malfunction. This performance deficiency was more than minor in accordance with IMC-0612, because it was associated with the Equipment Performance attribute of the Mitigating Systems cornerstone and adversely affected its objective of ensuring the availability, reliability, and operability of systems that respond to initiating events to prevent undesirable consequences. The intermittent failures of the MCO switches prevented successful breaker operation that impacted associated safetyrelated components utilized to mitigate design basis events. The finding was determined to be of very low safety significance (Green), following IMC-0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, and the resultant conclusion by the Region I Senior Reactor Analyst following performance of the Significance Determination Process (SDP) Phases 1, 2 and 3. This finding has a cross-cutting aspect in the area of Problem Identification and Resolution associated with the attribute of Operating Experience, because Entergy personnel did not utilize available vendor, external and internal operating experience information to support plant safety, in that they did not identify and prioritize replacement of degraded MCO switches with the improved/enhanced switches that have been available since 2003. P.2(b) per IMC 0310] |
| Site: | Indian Point  |
|---|---|
| Report | IR 05000286/2012002 Section 4OA2 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | J Furia M Gray M Halter P Cataldo S Barr |
| INPO aspect | |
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Finding - Indian Point - IR 05000286/2012002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Indian Point) @ 2012Q1
Self-Identified List (Indian Point)
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