05000361/FIN-2009003-02
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Failure to Implement Corrective Actions to Prevent Repeat Safety-related 480V Breaker Failures |
| Description | A self-revealing noncited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, was identified for the failure to implement timely corrective actions to preclude repetition of a significant condition adverse to quality involving the failure of a safety-related 480 volt circuit breaker. Specifically, the licensee did not properly evaluate the extent of condition for other risk significant breakers and promptly implement corrective actions following a previous failure of a safety-related 480 volt circuit breaker in March 2005 to preclude repetition of another safety-related 480 volt circuit breaker failure on March 28, 2009. This finding was entered into the licensees corrective action program as Nuclear Notification 200378783. This finding is greater than minor because it is associated with the equipment performance attribute of the Mitigating Systems Cornerstone and affects the associated cornerstone objective of ensuring the availability, reliability and capability of systems that respond to initiating events to prevent undesirable consequences. Using the Significance Determination Process Phase 1 Screening Worksheet for the Initiating Events, Mitigating Systems, and Barriers Cornerstones provided in Manual Chapter 0609, Attachment 4, Phase 1 Initial Screening and Characterization of Findings, the inspectors determined that this finding represented a loss of safety function of a single train for greater than its technical specification allowed outage time. This required that a Phase 2 estimate be completed using Manual Chapter 0609, Significance Determination Process, Appendix A, Determining the Significance of Reactor Inspection Findings for At Power Situations, and the Phase 2 Worksheets for San Onofre Nuclear Generation Station. The inspectors assumed that the performance deficiency affected the risk of operating the plant from March 11, 2009, when the last successful surveillance was completed through April 1, 2009, when the breaker was restored to a functional status. As a result, in accordance with Appendix A, Attachment 1, step 2.1.2, Determine the Appropriate Exposure Time, the inspectors selected an exposure period of 3-30 days. Using the Risk-Informed Inspection Notebook for SONGS Units 2 and 3, Revision 2.1a, the inspectors selected One Containment Fan Cooling Unit, as the appropriate target for the subject finding in the presolved table. Based on the results of the Phase 2 analysis, the finding is determined to have very low safety significance. This finding has a crosscutting aspect in the area of human performance associated with decision-making because safety-significant decisions were not reviewed to verify the validity of the underlying assumptions and identify possible unintended consequences H.1(b) (Section 1R12) |
| Site: | San Onofre  |
|---|---|
| Report | IR 05000361/2009003 Section 1R12 |
| Date counted | Jun 30, 2009 (2009Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | L Ricketson J Reynoso W Sifre G Warnick M Young A Fairbanks M Catts B Correll E Ruesch C Ryan T Buchanan A Vegel |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
| ' | |
Finding - San Onofre - IR 05000361/2009003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (San Onofre) @ 2009Q2
Self-Identified List (San Onofre)
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||