05000244/FIN-2015008-02
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Finding | |
|---|---|
| Title | Spurious Operation of Pressurizer Power Operated Relief Valves not Analyzed |
| Description | Failure to analyze the effects of spurious operation of a PORV was a PD. Specifically, Exelon's safe shutdown methodology postulated spurious operation of the PORVs, but had not analyzed the effect of the spurious operations. Exelon's safe shutdown analysis assumed operators had 23.9 minutes after a fire induced plant trip to re-establish the reactor coolant makeup (i.e., charging), but non-conservatively assumed that the PORVs remained closed. In addition, Exelon relied upon a non-time critical operator manual action to de-energize the PORV circuits from outside the control room after control room abandonment. This PD was more than minor because it was similar to Example 3.k of IMC 0612, Appendix E, Examples of Minor Issues, which determined that calculation errors would be more than minor if, as a result of the errors, there was reasonable doubt of the operability of the component. For this issue, the team had a reasonable doubt as to whether operators had sufficient time to re-establish charging to maintain pressurizer level within the indicated range. In addition, this issue was associated with the Protection Against External Factors (e.g., fire) attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective to ensure the availability and reliability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). The team performed an SDP Phase 1 screening, in accordance with IMC 0609, Appendix F. This deficiency affected the post-fire safe shutdown category because Exelon's safe shutdown analysis was incomplete. This issue was screened to very low safety significance (Green) because it was assigned a low degradation rating. The team determined this issue had a low degradation rating because Exelon's subsequent evaluation determined that the performance goals of Appendix R,Section III.L.2 were still satisfied, based on more restrictive administrative limits for RCS leakage than the Technical Specifications limits assumed in the original calculation. In addition, Exelon evaluated this issue with Ginna's fire probabilistic risk assessment (PRA) analysis and determined that the change in core damage frequency (CDF) attributed to this issue was in the low E-7 range. A Region I Senior Reactor Analyst reviewed Exelon's evaluation and concluded that the risk estimate was bounded by conservative assumptions and that this issue was of very low safety significance (Green). Cross-cutting aspects are not applicable to issues involving enforcement discretion. Ginna License Condition 2.C.(3), in part, required Exelon to implement and maintain in effect all fire protection features described in licensee submittals and as approved by the NRC. The Ginna FPP stated that the requirements of Appendix R,Section III.L were applicable for areas where alternative shutdown capability was selected and the control complex was designated as an alternative shutdown area. Appendix R,Section III.L.2 performance goals stated that pressurizer level shall remain within the indicated range. Contrary to the above, from March 2006 until present, Exelon had not adequately determined that pressurizer level would remain within the indicated range during alternative shutdown operations. Specifically, DA-EE-2000-066 determined that a fire in the control complex could result in spurious opening of a PORV until completion of an operator action outside of the control complex to de-energize the circuit. However, calculation DA-ME-2000-075 determined the time available for operators to re-establish charging following control room abandonment but assumed that the PORVs remained free of fire damage and did not spuriously open. Exelon entered this deficiency into its CAP as CRs 02563631 and 02563632. Exelon was in transition to NFPA 805 and, therefore, this NRC-identified issue was evaluated in accordance with the criteria established in NRC Enforcement Policy Section 9.1 and IMC 0305, Section 11.05. Because all the criteria were satisfied, the NRC exercised enforcement discretion and did not issue a violation for this issue. |
| Site: | Ginna  |
|---|---|
| Report | IR 05000244/2015008 Section 1R05 |
| Date counted | Dec 31, 2015 (2015Q4) |
| Type: | Violation: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | J Richmond J Rogge L Dumont S Galbreath W Cook |
| Violation of: | Technical Specification License Condition - Fire Protection License Condition |
| INPO aspect | |
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Finding - Ginna - IR 05000244/2015008 | ||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Ginna) @ 2015Q4
Self-Identified List (Ginna)
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