05000395/FIN-2012004-04
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Finding | |
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Title | Licensee-Identified Violation |
Description | TS 6.8.1a requires in part that written procedures shall be established covering the activities referenced in Regulatory Guide 1.33, Rev. 2, Appendix A, Section 9, Procedures for Performing Maintenance. Contrary to the above, on April 18, 2011, the licensee failed to adequately establish general maintenance procedure, GMP- 100.007, Maintenance Support for Refueling, because the lack of instructions resulted in the failure to ensure hold-down bolts were installed in the control rod drive mechanism cable bridge during the previous refueling outage. This adverse condition resulted in the inoperability of core exit thermocouples and reactor vessel level indication system due to damage sustained to cables and tubing, respectively, during a loss of coolant accident. This issue is more than minor and therefore a finding because it impacted the mitigating systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences and the attribute of procedure quality. The inspectors used IMC 0609, Attachment 4 and Appendix A, and determined the finding would require a detailed risk analysis by a regional senior reactor analyst. The failure to reinstall the refueling cable bridge hold down bolts was a performance deficiency (PD). The PD was more than minor because it impacted the equipment reliability attribute of systems required for mitigating accidents as the cable bridge could have moved following a loss of coolant accident impacting the core exit thermocouples and the reactor vessel level indicating system. The phase 1 significance determination process screening determined that the PD resulted in a potential loss of a safety function and required a detailed evaluation. A phase 3 SDP risk evaluation was performed by a regional senior reactor analyst using the V. C. Summer SPAR model. A one year exposure period was used and the human error probability of all Loss of Coolant Accident operator action basic events was increased due to the PD. The result of the risk analysis was an increase in the core damage frequency of < 1 E-6/year, a GREEN finding or very low safety significance. This finding has been entered into the licensees CAP as CR-11-01807. |
Site: | Summer ![]() |
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Report | IR 05000395/2012004 Section 4OA7 |
Date counted | Sep 30, 2012 (2012Q3) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | Licensee-identified |
Inspection Procedure: | |
Inspectors (proximate) | C Dykes C Fontana D Berkshire E Coffman G Mccoy J Dodson J Reece R Hamilton R Kellner |
INPO aspect | |
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Finding - Summer - IR 05000395/2012004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Summer) @ 2012Q3
Self-Identified List (Summer)
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