05000458/FIN-2017001-03
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Finding | |
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| Title | Failure to Enter Applicable Technical Specification Action Statements When Control Building Chillers Were O ut of Service |
| Description | Green . The inspectors identified a non- cited violation of Technical Specifications 3.8.4, DC Sources - Operating, 3.8.7, Inverters Operating, and 3.8.9, Distribution Systems Operating, for the licensees failure to either restore inoperable electrical power subsystems, inverters, and distribution subsystems to operable status within the applicable completion times, or be in Mode 3 in 12 hours and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Specifically, electrical power systems required by the above limiting condition s for operation were inoperable due to the associated division of the control building chilled water system chillers being out of service and therefore unavailable to provide the technical specification support function of attendant cooling that is needed for the associated electrical systems to perform their specified safet y functions. As a result of this deficiency, the station reduced the reliability and availability of systems cooled by control building chilled water system chillers by allowing configurations that did not conform to the single failure criterion. The lic ensee entered this issue into their corrective action program as Condition Report CR- RBS -2015 -02525 . Corrective actions included entering the appropriate limiting conditions for operation of affected safety -related systems when the non -safety related support system were non -functional. 4 The failure to either restore inoperable electrical power subsystems, inverters, and distribution subsystems to operable status within the applicable completion times, or be in Mode 3 in 12 hours and Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> wa s a performance deficiency . Specifically, electrical power systems required by the above limiting condition s for operation were inoperable due to the associated division of the control building chilled water system chillers being out of service and therefore unavailable to provide the technical specification support function of attendant cooling that is needed for the associated electrical systems to perform their specified safety functions. The performance deficiency was more than minor, and therefore a finding, because it wa s associated with the configuration control attribute of the Mitigating Systems Cornerstone, and adversely affected the associated cornerstone objective to ensure availability, reliability, and capability of systems that res pond to initiating events to prevent undesirable consequences. As a result of this deficiency, the station reduced the reliability and availability of systems cooled by control building chilled water system chillers by allowing configurations that did not conform to the single failure criterion. The inspectors performed an initial screening of the finding in accordance with NRC Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process (SDP) for Findings At -Power. Using NRC Inspection Manual Chapter 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions, the finding was determined to require a detailed risk evaluation because it represented a loss of system and/or function. A senior reactor analyst performed a det ailed risk evaluation for a previously identified performance deficiency associated with the licensees failure to account for a loss of all control building chilled water system cooling scenario, either quantitatively or qualitatively, which resulted in uncompensated impairment to all systems associated with the main control room (Agencywide Documents Access and Management System (ADAMS) Accession N o. ML16132A144). This previously performed detailed risk evaluation bounds the risk associated with the finding dispositioned in this write- up: the failure to either restore inoperable electrical power subsystems, inverters, and distribution subsystems to operable status within the applicable completion times, or be in Mode 3 in 12 hours and Mode 4 in 36 hours. Therefore, the finding was determined to be of very low safety significance (Green). No cross -cutting aspect was assigned as the performance deficiency is not indicative of current licensee performance |
| Site: | River Bend  |
|---|---|
| Report | IR 05000458/2017001 Section 4OA5 |
| Date counted | Mar 31, 2017 (2017Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 2515/165 |
| Inspectors (proximate) | B Parks C Young F Ramirez G Warnick J Drake J O'Donnell J Sowa N Greene |
| Violation of: | Technical Specification |
| INPO aspect | |
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Finding - River Bend - IR 05000458/2017001 | |||||||||||||||||||||||||||||||||||||||||||
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Finding List (River Bend) @ 2017Q1
Self-Identified List (River Bend)
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