05000445/FIN-2016004-01
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Finding | |
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| Title | Failure to Evaluate Inservice Testing Results of Power Operated Relief Valve |
| Description | Green. The inspectors identified a non-cited violation of 10 CFR 50, Appendix B, Criterion XI, Test Control, for the licensees failure to evaluate inservice testing results of a power operated relief valve (PORV). Specifically, the licensee restored a unit 1 PORV to service that did not meet its specified opening time, which resulted in the inoperability of the low temperature overpressure protection (LTOP) system. Following maintenance on PORV 1-PCV-455A during October 2014, the licensee performed stroke time testing on the valve, but failed to recognize that the valve exceeded its test acceptance criteria until it failed again in May 2016. The licensee entered this issue into the corrective action program as CR-2016-003920. The failure to evaluate test results to ensure they met test requirements is a performance deficiency. The performance deficiency was more than minor, and therefore a finding, because it was associated with the Reactor Coolant System Equipment and Barrier Performance attribute of the Barrier Integrity cornerstone and affected the cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. Using Inspection Manual Chapter 0609, Attachment 04, Initial Characterization of Findings, dated October 7, 2016, Inspection Manual Chapter 0609, Appendix G, Shutdown Operations Significance Determination Process, dated May 9, 2014, and Appendix G Attachment 1, Phase 1 Initial Screening and Characterization of Findings, Exhibit 4, Barrier Integrity Screening Questions, the inspectors determined the finding affected the Barrier Integrity cornerstone and required a detailed risk evaluation because the finding involved the unavailability of a PORV during LTOP operations. Using the assumption that the slow opening time prevents the PORV from fulfilling its LTOP system function, a senior reactor analyst performed a bounding qualitative assessment, using Inspection Manual Chapter 0609, Appendix G, Shutdown Operations Significance Determination Process. The influential assumptions used by the senior reactor analyst included an exposure time of approximately 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> and that the licensee maintained the availability of a single additional relief valve with capability sufficient to mitigate an LTOP event as described in the final safety analysis report. Using these assumptions, the senior reactor analyst determined that a bounding increase in core damage frequency for this issue was 1.45E-8 per year and was therefore, of very low safety significance (Green). The finding has a human performance cross-cutting aspect associated with work management, in that, the licensee failed to ensure that the work process includes the need for coordination with different groups or job activities [H.5]. |
| Site: | Comanche Peak  |
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| Report | IR 05000445/2016004 Section 1R04 |
| Date counted | Dec 31, 2016 (2016Q4) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.04 |
| Inspectors (proximate) | E Simpson J Groom J Josey J Tapp K Clayton L Brandt R Kumana T Farina W Gardner |
| Violation of: | 10 CFR 50 Appendix B Criterion XI |
| CCA | H.5, Work Management |
| INPO aspect | WP.1 |
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Finding - Comanche Peak - IR 05000445/2016004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Comanche Peak) @ 2016Q4
Self-Identified List (Comanche Peak)
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