05000333/FIN-2016007-02
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Finding | |
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| Title | Failure to adequately evaluate a procedure change impacting a PRA-credited time critical operator action |
| Description | The team identified a Green finding involving Entergys inability to complete a time critical operator action within the assumed probabilistic risk assessment (PRA) credited accident mitigation time limit to prevent undesirable consequences (i.e., core damage) under a postulated scenario (i.e., using the residual heat removal service water (RHRSW) system as an alternate injection source into the reactor pressure vessel (RPV) via the residual heat removal (RHR) system during a loss of coolant accident (LOCA)). Specifically, in response to a known degraded condition impacting an RHRSW valve, Entergy did not adequately evaluate an associated temporary procedure change to EP-8, Alternate Injection Systems, to ensure operator actions could be accomplished to initiate RHRSW injection to the RPV within the PRA-credited time. Entergy entered the issue into their CAP as CR 2016-1396 and CR 2016-1429 and completed corrective actions to pre-stage a ladder for operator use and provide additional guidance to plant operators. The finding was more than minor because it was associated with the design control (plant modifications) attribute of the Mitigating Systems cornerstone and adversely affected the cornerstones objective of ensuring reliability, availability, and capability of systems and operators that respond to initiating events to prevent undesirable consequences (i.e., core damage). The team evaluated the finding in accordance with IMC 0609, Appendix A, The Significance Determination Process for Findings at Power, Exhibit 2 Mitigating Systems Screening Questions, and concluded it required a detailed risk evaluation (DRE). A Region I Senior Reactor Analyst performed the DRE and concluded that the failure of an operator action to align RHRSW for RPV alternate injection within the assumed PRA accident mitigation time limit results in an estimated increase in core damage frequency in the mid E-8/year range, or very low safety significance (Green). The finding had a cross-cutting aspect in the area of Problem Identification and Resolution, Evaluation, because Entergy did not thoroughly evaluate issues to ensure that resolutions address causes and extent-of-conditions commensurate with their safety significance. Specifically, Entergy did not thoroughly evaluate the effect of an alternate injection procedure change on PRA-credited time critical operator actions. [PI.2] |
| Site: | FitzPatrick  |
|---|---|
| Report | IR 05000333/2016007 Section 1R21 |
| Date counted | Jun 30, 2016 (2016Q2) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21M |
| Inspectors (proximate) | D Kern H Gray J Ayala J Schoppy J Zudans P Krohn S Kobylarz |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - FitzPatrick - IR 05000333/2016007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (FitzPatrick) @ 2016Q2
Self-Identified List (FitzPatrick)
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