05000414/FIN-2017011-01
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Finding | |
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| Title | Failure to Adequately Establish and Adjust Preventive Maintenance for Emergency Diesel Generator Excitation System Diodes. |
| Description | To Be Determined (TBD): The inspectors identified an AV of Technical Specification 5.4.1.a, Procedures, for the licensees failure to adequately develop and adjust the preventive maintenance strategy for the emergency diesel generator (EDG) excitation system in accordance with AD-EG-ALL-1202, "Preventive Maintenance and Surveillance Testing Administration." The inspectors also identified an associated AV of Title 10 of the Code of Federal Regulations (10 CFR) Part 50 Appendix B, Criterion XVI, Corrective Actions, for the failure to correct a condition adverse to quality associated with elevated operating temperatures of EDG excitation system diodes. This resulted in the failure of an EDG excitation system diode and overcurrent trip of the 2A emergency diesel output breaker during a surveillance test performed on April 11, 2017. The licensee entered this condition into their corrective action program as Condition Report 2116069. The 2A EDG was returned to service on April 14, 2017 follo wing replacement of the excitation system diodes. The failure to adequately develop and adjust preventive maintenance activities in accordance with AD-EG-ALL-1202, thus allowing a condition adverse to quality to remain uncorrected, was a performance deficiency. This performance deficiency was more than minor because it affected the mitigating systems cornerstone attribute of equipment performance and affected the cornerstone objective of ensuring the availability, reliability, and capability of systems and components that respond to initiating events to preclude undesirable consequences (i.e. core damage). Spec ifically, failure to adjust the preventive maintenance activities for the EDG excitation sy stem by incorporating operating experience, corrective maintenance history, and structures, systems, and components (SSC) performance history led to the failure of diode CR4 in the EDG excitation system and caused the 2A EDG output breaker to trip open on April 11, 2017. Using NRC Inspection Manual Chapter 0609, Attachment 4, Initial Characterization of Findings, dated June 19, 2012, the inspectors determined that the issue affected the mitigating systems cornerstone. In accordance with NRC Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process (SDP) for Findings at Power, dated June 19, 2012, the inspectors determined that the issue required a detailed risk evaluation because the finding represents an actual loss of function of a single train for greater than its technical specification allowed outage time. This finding has a cross-cutting aspect of oper ating experience in the area of problem identification and resolution, because the organiza tion did not systematically and effectively evaluate relevant internal and external operating experience in a timely manner. Specifically, Condition Report 1566561 doc umented industry operating experience regarding EDG excitation system diodes failing at an increased rate and that operating experience was not effectively implemented and institutionalized through changes to station processes, procedures, and equipment. This issue is indicative of current performance because the station did not take effective corrective actions to address the degradation of the EDG excitation system |
| Site: | Catawba  |
|---|---|
| Report | IR 05000414/2017011 Section 1R15 |
| Date counted | Sep 30, 2017 (2017Q3) |
| Type: | Violation: White |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | J Austin C Scott F Ehrhardtn Securityj Austinc Scott |
| Violation of: | Technical Specification - Procedures |
| CCA | P.5, Operating Experience |
| INPO aspect | CL.1 |
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Finding - Catawba - IR 05000414/2017011 | |||||||||||||||||||||
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Finding List (Catawba) @ 2017Q3
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