05000327/FIN-2013014-01
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Finding | |
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| Title | Failure to Adequately Translate Design Basis Into Procedure Acceptance Criteria Time to Perform Operator Action |
| Description | The team identified a non-cited violation of 10 CFR 50, Appendix B, Criterion III, Design Control, for the licensees failure to correctly translate design basis requirements into emergency sub-procedure, ES-1.3, Transfer to Residual Heat Removal Containment Sump, Revision 19. Specifically, the time allotted for operators to perform time critical actions to swap emergency core cooling system (ECCS) pump suction from the refueling water storage tank (RWST) to the containment sump during a small break loss of coolant accident (SBLOCA) did not properly account for full range of instrument uncertainties (instrument, instrument calibration, instrument loop uncertainties, etc...) and the accident analysis design basis requirement in Updated Final Safety Analysis Report 15.3.1, to ensure the recovery of the core was demonstrated and to ensure continuous operation of the ECCS. This was a performance deficiency. As immediate corrective action, the licensee performed an operability review and documented the results in the corrective action program as problem evaluation reports 760336 and 758761. The licensee concluded that there were no current operability concerns, and created Standing Order SO-13-025 to reinforce operator time performance requirements. The performance deficiency was determined to be more than minor because it affected the Design Control attribute of the Mitigating Systems cornerstone, and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of containment spray pumps, safety injection pumps, and charging pumps during a SBLOCA. Specifically, the licensee failed to demonstrate that operators would be able to successfully complete the time critical actions (TCAs) prior to reaching 8 percent RWST tank level which required operators to secure all pumps taking suction from the RWST. From the licensees calculations evaluating and documenting the basis for the TCAs, the licensee had not considered the worst case allowable acceptance criteria for RWST level instrument uncertainties from calibrations or instrument loops in conjunction with the design pump flow rates. This action would result in the momentary loss of all ECCS high pressure injection during a SBLOCA and did not ensure the availability, reliability, and capability of the ECCS to respond to initiating events. The team used Inspection Manual Chapter 0609, Significance Determination Process, Attachment 4, Initial Characterization of Findings, and Appendix A, The Significance Determination Process for Findings At-Power. The Senior Reactor Analyst completed a Phase 3 detailed risk evaluation and determined the finding to be of very low safety significance. This finding was not assigned a cross-cutting aspect because the underlying cause was not indicative of present licensee performance. |
| Site: | Sequoyah  |
|---|---|
| Report | IR 05000327/2013014 Section 1R21 |
| Date counted | Dec 31, 2013 (2013Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | J Bartley N Coovert R Nease T Fanelli |
| Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
| INPO aspect | |
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Finding - Sequoyah - IR 05000327/2013014 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Sequoyah) @ 2013Q4
Self-Identified List (Sequoyah)
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