05000275/FIN-2014004-04
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Finding | |
|---|---|
| Title | Inadequate Procedure Results in Unnecessary Main Steam Safety Valve Lift |
| Description | The inspectors identified a Green non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, for the licensee failure to prescribe a procedure appropriate to the circumstances with respect to safetyrelated atmospheric dump valves and main steam safety valves. Specifically, control of atmospheric steam dump valves was not appropriate for a rapid plant shutdown resulting in unnecessary lifting of a spring-loaded main steam safety valve. The inspectors determined that the licensees failure to ensure appropriate procedures to properly control steam generator pressure and prevent unnecessary lifting of main steam safety valves was a performance deficiency. This performance deficiency was determined to be more than minor because it affected the Mitigating Systems cornerstone attribute of procedural quality and the objective of ensuring the availability and reliability of systems that respond to initiating events to prevent undesirable consequences. Using Inspection Manual Chapter 0609, Attachment 04, Initial Characterization of Findings, and Appendix A, Exhibit 2, Mitigating Systems Screening Questions, the finding was determined to be of very low safety significance (Green) because the finding was a deficiency affecting the design or qualification of a mitigating structure, system, or component that did not affect operability or functionality. The inspectors concluded that this finding affected the cross-cutting aspect of human performance associated with avoiding complacency, because the licensee failed to recognize during rapid load reductions the inherent risk of lifting a main steam safety valve and did not recognize or plan with adequate procedures, for a condition with a potential latent problem. |
| Site: | Diablo Canyon  |
|---|---|
| Report | IR 05000275/2014004 Section 4OA3 |
| Date counted | Sep 30, 2014 (2014Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | C Alldredge C Osterholtz J Mateychick J O'Donnell J Reynoso L Carson L Micewski L Ricketson M Bloodgood N Greene T Hipschman W Walker |
| Violation of: | 10 CFR 50 Appendix B Criterion V |
| CCA | H.12, Avoid Complacency |
| INPO aspect | QA.4 |
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Finding - Diablo Canyon - IR 05000275/2014004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Diablo Canyon) @ 2014Q3
Self-Identified List (Diablo Canyon)
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