05000440/FIN-2017009-01
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Finding | |
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| Title | Unsuitable Application of Surge Suppression Diodes in Standby Diesel Generator Control Power Circuitry |
| Description | Preliminary White . The inspectors identified a finding preliminarily determined to be of low to moderate safety significance (White), and an associated apparent violation of Title 10 of the Code of Federal Regulations (10 CFR) 50, Criterion III , Design Control, for the licensees failure to implement measures for the selection and review for suitability of application of voltage suppression diodes installed in the control circuitry for the Division 2 Standby Diesel Generator, which was a component subject to the requirements of 10 CFR Part 50, Appendix B. Specifically , Engineering Change Package 04 00049 failed to consider the effects of a shorted diode on the control circuitry for the Division 2 Standby Diesel Generator, and instead, introduced new components (diodes) into the control circuitry that resulted in the eventual failure of this safety -related equipment . This rendered the standby diesel generator inoperable and unable to start for longer than its technical specification allowed outage time , which was a violation of Technical Specification 3.8.1, AC Sources -Operating . The licensee documented the issue in CR 2016 13183, and subsequently replaced the failed component and then modified circuitry to remove the replacement diode and the remaining diodes from similar components. The inspectors determined that the licensees failure to evaluate the effects of voltage suppression diode failure on the Standby Diesel Generator control circuit was contrary to the requirements of 10 CFR Part 50, Appendix B , Criterion III and a performance deficiency which was within the licensees ability to foresee and prevent . The inspectors determined that the performance deficiency was of more than minor significance because it was associated with the design control attribute of the mitigating syst ems cornerstone 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, the design of the Division 2 Standby Diesel Generator control circuit resulted in the inoperability and unavailability of the Division 2 Standby Diesel Generator from April 2, 2015, to November 8, 2016, when the failed diode was replaced. 3 A Significance and Enforcement Revi ew Panel, using IMC 0609, Appendix A, Significance Determination Process for Findings At -Power, dated June 19, 2012, preliminarily determined the finding to be of low -to-moderate safety significance. The inspectors did not identify any cross- cutting aspects associated with this finding because the condition had existed since at least 2007, when the diodes were originally installed in the DC control power circuits, and therefore, was not indicative of current plant performance |
| Site: | Perry  |
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| Report | IR 05000440/2017009 Section 4OA2 |
| Date counted | Jun 30, 2017 (2017Q2) |
| Type: | AV: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | C Pedersonr Elliottj Nance M Doyle I Hafeez I Khan L Kozak J Robbins J Cameron |
| Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
| INPO aspect | |
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Finding - Perry - IR 05000440/2017009 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Perry) @ 2017Q2
Self-Identified List (Perry)
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