05000336/FIN-2016001-01
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Finding | |
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| Title | Repetitive Failures to Correct Unit 3 Turbine Driven Auxiliary Feedwater Pump Performance Issues |
| Description | The inspectors identified a Green NOV of Title 10 of the Code of Federal Regulations (10 CFR) 50, Appendix B, Criterion XVI, Corrective Action, for Dominions repetitive failure to take effective corrective actions for significant conditions adverse to quality involving the degradation of the Unit 3 turbine driven auxiliary feedwater (TDAFW) pump turbine control valve linkage. Specifically, Dominions corrective actions to correct the TDAFW control system have not fully considered all potential failure modes such that continued unreliable operation due to linkage and control systems problems resulted in an overspeed trip of the TDAFW system in February 2016. Inspectors have previously documented this condition under two separate violations of 10 CFR 50, Appendix B, Criterion XVI. The performance deficiency was determined to be more than minor since it was associated with the equipment performance attribute of the Mitigating Systems cornerstone and adversely affected its objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. In accordance with IMC 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions, the inspectors determined this issue required a detailed risk evaluation based on the finding representing an actual loss of function of a single train for greater than its technical specification (TS) allowed outage time. A Region I Senior Reactor Analyst (SRA) completed a detailed risk evaluation and concluded the risk significance of this issue was in the high E-8 range, or very low safety significance (Green). In accordance with IMC 0310, Aspects within the Cross-Cutting Areas, dated December 4, 2014, this finding has a cross-cutting aspect in Human Performance, Design Margins, in that the organization failed to operate and maintain equipment within design margins. The Unit 3 TDAFW has little margin to inoperability. Dominion did not pursue a thorough review of the potential interactions of different failure modes after correcting the obvious causes from past failures, which contributed to the February 22, 2016, overspeed event [H.6]. |
| Site: | Millstone  |
|---|---|
| Report | IR 05000336/2016001 Section 1R15 |
| Date counted | Mar 31, 2016 (2016Q1) |
| Type: | Violation: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | C Highley C Newport G Dentel J Ambrosini K Reid L Mckown |
| Violation of: | 10 CFR 50 Appendix B Criterion XVI Technical Specification |
| CCA | H.6, Design Margins |
| INPO aspect | WP.2 |
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Finding - Millstone - IR 05000336/2016001 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Millstone) @ 2016Q1
Self-Identified List (Millstone)
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