05000352/FIN-2009004-01
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Finding | |
|---|---|
| Title | Failure to Adequately Test 480 Volt Motor Control Unit Circuit Breakers |
| Description | The inspectors identified a Green NCV of 10 CFR Part 50, Appendix B, Criterion XI, Test Control, for failure to establish a test program for all safety-related 480 volt motor control unit (MCU) circuit breakers to assure that necessary testing was performed to demonstrate that they would perform the safety-related function in service. Specifically, in 2004, Exelon inappropriately classified certain safety-related 480 volt molded-case circuit breakers as run-to-failure in the Performance Centered Maintenance (PCM) process, which resulted in the breakers receiving no planned preventive maintenance or testing. Exelon entered this issue into the Corrective Action Program (CAP) for resolution as Issue Report (IR) 948232. Exelons corrective actions included: reclassifying all safety-related 480 volt MCUs as either critical or non-critical, a formal review of the vendors technical bulletin for applicability; and an extent-of-condition review of all direct current MCUs and 4 kilovolt circuit breakers. Also, preventive maintenance and testing was planned for all in-service 480 volt MCUs that had gone overdue because they were inappropriately classified as run-to-failure. This finding is more than minor because, if left uncorrected, the performance deficiency would lead to a more significant safety concern. Specifically, the installed molded case circuit breakers classified as run-to-failure had received no periodic planned maintenance or tests and were beyond the manufacturers design life. Based on operating experience, this would result in a breaker being slow to trip or sticking in the on position after an over-current condition. The inspectors assessed the finding using Phase 1 of IMC 0609, Attachment 4, Phase 1 Initial Screening and Characterization of Findings and determined the finding to be of very low safety significance because the issue was a qualification deficiency confirmed not to result in loss of operability per Part 9900, Technical Guidance, Operability Determination Process for Operability and Functional Assessment. Since the change to the PCM process was made in 2004, the inspectors determined that this finding was not reflective of current licensee performance and, therefore, did not have a cross-cutting aspect |
| Site: | Limerick  |
|---|---|
| Report | IR 05000352/2009004 Section 1R12 |
| Date counted | Sep 30, 2009 (2009Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | E Dipaolo T Moslak J Lilliendahl J Kulp N Sieller P Krohn E Torres N Lafferty |
| INPO aspect | |
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Finding - Limerick - IR 05000352/2009004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Limerick) @ 2009Q3
Self-Identified List (Limerick)
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