05000353/FIN-2011004-01
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Finding | |
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| Title | |
| Description | A self-revealing preliminary white finding and apparent violation of Technical Specification (TS) 3.7.3, Reactor Core Isolation Cooling System and TS 3.6.3, Primary Containment Isolation Valves, was identified. The inspectors determined that the failure by Exelon to ensure sufficient technical guidance was contained in operating procedures to: 1) ensure that a Main Feedwater system (FW) motor-operated valve (MOV) could close against expected system differential pressures and 2) prevent operators from attempting to close FW MOVs out of sequence resulting in differential pressures for which they are not designed; is a performance deficiency. This resulted in the Reactor Core Isolation Cooling system (RCIC) and a Primary Containment Isolation Valve (PCIV) being inoperable from April 23 to May 23, 2011, due to FW MOVs HV-041-209B and HV-041-210 failing to fully shut. As a result, both safety related systems were inoperable for greater than their Technical Specification allowed outage times. Specifically, operations procedures did not contain adequate technical guidance to ensure that operations personnel operated HV-041209 A&B and HV-041-210 in the proper sequence to remain within valve design limitations. This resulted in the HV-041-209B and HV-041-210 valves failing to fully close on April 22, 2011, although they indicated closed in the Main Control Room. Upon identification, Limerick operations staff fully closed the valves restoring RCIC and PCIV operability, entered the issue into the CAP as issue report (IR) 1219476 and conducted a cause evaluation. Subsequent corrective actions included an extent-of-condition review, revisions to the operating procedure, and revisions to maintenance and testing procedures. The inspectors determined that this finding is more than minor because it is associated with the equipment performance attribute of the Mitigating Systems Cornerstone and affects the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, operating procedures, maintenance and testing were not adequately implemented to ensure that the design capability of HV-041-209B and HV-041-210 to close against expected system differential pressures was maintained. The finding was evaluated using NRC Inspection Manual Chapter 0609 Appendix A, User Guidance for Significance Determination of Reactor Inspection Findings for At-Power Situations. Phase I, II, and III evaluations were conducted. The NRC total estimated L\\\\CDF in this preliminary assessment is Low E-6/yr (WHITE) and the NRC total estimated Large Early Release Frequency (LiLERF) in this preliminary assessment is 3.6E-9/yr (GREEN). The inspectors also determined that this issue has a cross-cutting aspect in the area of Human Performance, Resources, because Exelon did not ensure long term plant safety by maintaining design margins and minimizing preventive maintenance deferrals [H.2. (a)]. Specifically, design limitations of the HV-041209 A & B valves were not adequately captured in the procedural guidance, which contributed to the operators continuing on in the procedures for securing the FW long path recirculation line up when problems with the HV-041-21 0 valve were encountered. Additionally preventive maintenance activities which could potentially have prevented this issue were deferred without an appropriate evaluation. |
| Site: | Limerick  |
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| Report | IR 05000353/2011004 Section 4OA2 |
| Date counted | Sep 30, 2011 (2011Q3) |
| Type: | Violation: White |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | A Rosebrook A Ziedonis D Roberts E Dipaolo E Miller J Ambrosini J Kulp J Lilliendahl J Nicholson K Mangan N Sieller S Hammann T Moslakk Mangann Sieller S Hammann T Moslak A Rosebrook A Ziedonis D Roberts E Dipaolo E Miller J Ambrosini J Kulp J Lilliendahl J Nicholson |
| CCA | H.6, Design Margins |
| INPO aspect | WP.2 |
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Finding - Limerick - IR 05000353/2011004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Limerick) @ 2011Q3
Self-Identified List (Limerick)
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