05000387/FIN-2010005-01
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Finding | |
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| Title | Failure to Adequately Evaluate Periods of Elevated Risk for Necessary Risk Management Actions |
| Description | An NRC-identified NCV of 10 CFR 50.65(a)(4) occurred when PPL failed to conduct an adequate risk assessment of online maintenance activities during the week of October 24, 2010. In one period of elevated risk on October 27, 2010, the entire duration in which valve functionality was affected was not appropriately accounted for in the risk assessment for work on the Residual Heat Removal Service Water (RHRSW) system. Though the maintenance window was calculated as Yellow risk, when the entire period of functionality was considered the duration of Yellow risk was extended from 9.5 to 12.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. Additionally, on October 26, 2010, online risk was calculated as Yellow for a period of 13.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> due to work on the Residual Heat Removal (RHR) system. In neither of these cases was the protected equipment program implemented as a risk management action as required by station procedures. PPL entered these issues into their CAP as condition reports (CRs) 1318550 and 1318602. This finding affected the Human Performance attribute of the Mitigating Systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). The finding is more than minor because it is similar to example 7.e. in IMC 0612 Appendix E, Examples of Minor Issues, in that failure to perform an adequate risk assessment when required by 10 CFR 50.65 (a)(4) is not minor if the overall elevated plant risk would put the plant into a higher licensee established risk category or would require, under plant procedures, risk management actions (RMAs) or additional RMAs. In one case, plant risk was reclassified from Green to Yellow when the maintenance was properly modeled and in both cases the maintenance duration was in excess of the PPL established threshold requiring protected equipment as an RMA; therefore, the violation is more than minor. The inspectors evaluated the finding using IMC 0612, Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process. Since the incremental core damage probability deficit was less than 1 E-6 and the incremental large early release probability deficit was less than 1 E-7, this finding is determined to be of very low safety significance (Green). This finding was determined to have a cross-cutting aspect in the area of Problem Identification and Resolution, Corrective Action Program. Specifically, though PPL had recognized a negative trend, as well as the underlying weaknesses in the assessment of on-line risk; prior to this violation occurring they failed to take appropriate corrective actions to address the adverse trend in a timely manner, commensurate with the safety significance and complexity. |
| Site: | Susquehanna  |
|---|---|
| Report | IR 05000387/2010005 Section 1R13 |
| Date counted | Dec 31, 2010 (2010Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | M Patel J Furia A Rosebrook P Finney P Krohn T Hedigan J Greives |
| CCA | P.3, Resolution |
| INPO aspect | PI.3 |
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Finding - Susquehanna - IR 05000387/2010005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Susquehanna) @ 2010Q4
Self-Identified List (Susquehanna)
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