05000346/FIN-2013002-03
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | The requirements of the NRC Maintenance Rule, 10 CFR 50.65(a)(4) state, in part, that the licensee shall assess and manage the increase in risk that may result from the proposed maintenance activities. Contrary to this requirement, on January 28, 2013, the licensees probabilistic risk assessment did not accurately reflect the increase in online probabilistic risk associated with startup transformer X01 being unavailable during planned maintenance. Specifically, while removing the 345 kV Lemoyne transmission line from service for planned maintenance, startup transformer X01 unavailability during switchyard manipulations was inadvertently omitted from the stations risk assessment. Re-performance of the risk assessment after the switchyard manipulations were already completed indicated that an elevated yellow risk category that required additional work controls had actually existed for approximately 16 minutes during the switchyard manipulations. Licensee personnel initiated CR 2013-01309 to document the issue. The objective of the Mitigating Systems Cornerstone of Reactor Safety is to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). A key attribute of this objective is equipment performance and availability. Using IMC 0609, Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process, the inspectors determined that the violation was of very low safety significance since the incremental core damage probability deficit calculated for the issue was less than 1E-6. |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2013002 Section 4OA7 |
| Date counted | Mar 31, 2013 (2013Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | A Wilson D Kimble D Reeser E Sanchez J Cameron R Langstaff R Winter S Bell T Briley |
| Violation of: | 10 CFR 50.65(a)(4) 10 CFR 50.65 |
| INPO aspect | |
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Finding - Davis Besse - IR 05000346/2013002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2013Q1
Self-Identified List (Davis Besse)
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