05000456/FIN-2010010-02
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Finding | |
|---|---|
| Title | Failure to replace low margin fuses in MCC131X1 |
| Description | A self-revealed finding of very low safety significance and an associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, was identified for the failure to establish measures for the selection and review for suitability of equipment essential to the safetyrelated function of the component. In 2008, the safety-related 1.5 ampere (amp) control power fuses in motor control center (MCC) 131X1 were specified to be replaced with 3.0 amp fuses due to failures of other similar 1.5 amp fuses. In 2009, these fuses failed and were replaced with the same sized 1.5 amp fuses, even though the licensees review for suitability concluded the fuses were adequate, but marginally sized. They were then scheduled to be replaced with 3.0 amp fuses in 2015. During the event on August 16, 2010, these fuses failed again at which time they were replaced with 3.0 amp fuses. The finding was determined to be more than minor because the finding was associated with the Mitigating Systems Cornerstone attribute of equipment performance and affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the failure of these fuses resulted in the loss of function for eight safety injection valves. This caused a train of emergency core cooling and containment isolation for the safety injection system to be inoperable. The inspectors answered no to the Mitigating Systems questions and screened the finding as having very low significance (Green). This finding has a cross-cutting aspect in the area of problem identification and resolution, corrective action program component, because the licensee did not implement corrective actions to address safety issues in a timely manner, commensurate with their safety significance. Specifically, in 2008 these 1.5 amp fuses were specified to be replaced with 3.0 amp fuses, they failed in 2009 and were replaced with 1.5 amp fuses. They were then scheduled for replacement with the higher amp fuses in 2015. |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2010010 Section 4OA5 |
| Date counted | Sep 30, 2010 (2010Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 93812 |
| Inspectors (proximate) | G Shear J Jandovitz M Thorpe Kavanaugh N Feliz Adomo T Go |
| Violation of: | 10 CFR 50 Appendix B 10 CFR 50 Appendix B Criterion III, Design Control |
| CCA | P.3, Resolution |
| INPO aspect | PI.3 |
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Finding - Braidwood - IR 05000456/2010010 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2010Q3
Self-Identified List (Braidwood)
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