05000410/FIN-2017002-01
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Finding | |
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| Title | Inadequate Extent of Condition Results inUnplanned Yellow Risk Condition |
| Description | The inspectors identified a Green non-cited violation (NCV) of Title 10 of the Code of Federal Regulation (10 CFR) 50.65(a)(4), Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, when Exelon did not assess and manage the increase in risk for online maintenance activities. Specifically, on May 24, 2017, the inspectors identified a planned surveillance activity which caused unavailability of the A residual heat removal (RHR) system minimum flow valve that was not recognized by the Exelon staff as a, Yellow, elevated risk activity in accordance with their EOOS (Equipment Out of Service) probabilistic risk assessment (PRA) model. Exelon staff generated issue report (IR) 04015294 to address the failure to recognize the Yellow, elevated risk activity and failure to review adequate extent of condition. Corrective actions include evaluating PRA to assess if risk can be reduced to Green with compensatory actions and providing training to operations to enhance PRA modeling of system availability. Following review of the PRA model, Exelon plans to evaluate all surveillance procedures as part of extent of condition that could impact availability of the A RHR minimum flow valves.This performance deficiency is more than minor because it affected the human performance attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, on May 24, 2017, the inspectors identified a planned activity that resulted in an unplanned Yellow risk activity during planned maintenance that resulted in unavailability of a component used to support the A RHR system. Additionally, this issue is similar to Example 7.f of IMC 0612, Appendix E, Examples of Minor Issues, issued August 11, 2009, because the overall elevated plant risk placed the plant into a higher licensee-established risk category. The inspectors determined that this finding is of very low safety significance (Green). Because the incremental core damage probability deficit was less than 1E-6 and the incremental large early release probability was less than 1E-7, this finding was determined to be of very low safety significance (Green). The cause of the finding has a cross-cutting aspect in the area of Human Performance, Teamwork, because Exelon staff did not effectively communicate internally to ensure that corrective actions were being addressed to resolve concerns with risk associated with A RHR minimum flow valve availability. Specifically, Exelon staff incorrectly believed that integrated risk management guidance corresponded to PRA availability. Thus, it was assumed risk would remain Green during surveillance and maintenance activities that resulted in the A RHR minimum flow valve being unavailable; and a failure to recognize future maintenance activities that resulted in risk being Yellow. [H.4] |
| Site: | Nine Mile Point  |
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| Report | IR 05000410/2017002 Section 1R13 |
| Date counted | Jun 30, 2017 (2017Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | E Miller K Kolaczyk G Stock O Masnyk-Bailey J Nicholson N Perry R Rolph K Warner |
| Violation of: | 10 CFR 50.65 10 CFR 50.65(a)(4) |
| CCA | H.4, Teamwork |
| INPO aspect | PA.3 |
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Finding - Nine Mile Point - IR 05000410/2017002 | |||||||||||||||||||||||||||||||||
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Finding List (Nine Mile Point) @ 2017Q2
Self-Identified List (Nine Mile Point)
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