05000458/FIN-2014005-02
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Finding | |
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Title | Failure to Lubricate Residual Heat Exchanger Bypass Valves |
Description | The inspectors reviewed a self-revealing, non-cited violation of Technical Specification 5.4.1.a, "Procedures," for the failure to develop lubrication schedules to ensure the reliability of safety-related motor operated valves (MOV). Specifically, the station failed to properly lubricate the residual heat removal B heat exchanger bypass valve E12-MOV- 48B which resulted in the failure of the valve to open when demanded during a system restoration alignment. The station repaired the valve, lubricated the torque arm bearing and all potentially affected torque arm bearings on similar motor operated valves, and updated the preventive maintenance procedure to include lubrication of torque arm bearings. The licensee entered this issue into their corrective action program as Condition Report CR-RBS-2014-04327. The inspectors determined that the failure of the licensee to promptly implement preventive maintenance to lubricate Velan-style MOV torque arm bearings was a performance deficiency. This performance deficiency is more than minor, and therefore a finding, because it is associated with the Mitigating Systems Cornerstone attribute of equipment performance, and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, E12-MOV-48B could not have performed its safety function to open upon a low pressure core injection initiation signal, due to the lack of lubrication on the valve's torque arm bearing. The senior resident inspector performed the initial significance determination for the inoperable Division II residual heat removal heat exchanger bypass valve. The inspector used the NRC Inspection Manual 0609, Appendix A, Exhibit 2, "Mitigating Systems Screening Questions," dated June 19, 2012, to evaluate this issue. The finding required a detailed risk evaluation because it involved the potential loss of a single train of safety equipment for longer than the technical specification allowed outage time. The exposure period was 8 days. A Region IV senior reactor analyst performed a detailed risk evaluation for this issue and determined that the change to the core damage frequency was much less than 1E-6, and therefore the finding was determined to be of very low safety significance (Green). The diverse coolant injection pathways helped to minimize the risk. This performance deficiency occurred in 2000 and, is not reflective of current licensee performance. |
Site: | River Bend |
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Report | IR 05000458/2014005 Section 4OA2 |
Date counted | Dec 31, 2014 (2014Q4) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | Self-revealing |
Inspection Procedure: | IP 71152 |
Inspectors (proximate) | A Barrett C Steely J Braisted J Groom J Sowa M Kennard T Farina |
Violation of: | Technical Specification - Procedures Technical Specification |
INPO aspect | |
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Finding - River Bend - IR 05000458/2014005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (River Bend) @ 2014Q4
Self-Identified List (River Bend)
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