05000317/FIN-2012004-03
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Finding | |
|---|---|
| Title | Inadequate Assessment of Unit 1 RCS Pressure Boundary Leakage |
| Description | A self-revealing NCV of Technical Specification (TS) 3.4.13, Reactor Coolant System (RCS) operational LEAKAGE, was identified because Constellation failed to completely isolate a fault in the RCS pressure boundary, which resulted in Constellation operating with RCS pressure boundary leakage for a period of time prohibited by Technical Specifications. Constellations corrective actions included entering the issue in their Corrective Action Program (CAP) (CR-2012-007012 and CR-2012-007276), performing repairs, and conducting root and apparent cause analyses for the issue. The finding is more than minor because it is associated with the equipment performance attribute of the Initiating Events cornerstone and affected the cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, after the Constellation personnel identified reactor coolant pressure boundary (RCPB) leakage at 5:15 p.m. on July 17, 2012, they did not reach Mode 3 within six hours because they did not verify complete isolation of the leak. Constellations actions did not limit the likelihood of a small loss of coolant accident (LOCA) event when they operated with RCS pressure boundary leakage from July 17 until July 21, 2012. The inspectors evaluated the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings at Power, and determined the finding is of very low safety significance (Green) because the performance deficiency, after a reasonable assessment of degradation, could not result in exceeding the RCS leak rate for a small LOCA and could not likely affect other systems used to mitigate a LOCA, resulting in a total loss of their function. The finding has a cross-cutting aspect in the area of Human Performance, Decision Making, because Constellation personnel did not use conservative assumptions in decision making and adopt a requirement to demonstrate that the proposed action was safe in order to proceed, rather than a requirement to demonstrate that it is unsafe in order to disapprove the action. Specifically, after attempting to isolate the RCS pressure boundary leakage, Constellation personnel non-conservatively assumed that the leak was isolated based on an inadequate post-isolation verification and monitoring plan. |
| Site: | Calvert Cliffs  |
|---|---|
| Report | IR 05000317/2012004 Section 1R15 |
| Date counted | Sep 30, 2012 (2012Q3) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | S Hammann T Ziev S Pindale J Schoppy R Barkley S Barr G Dentel S Kennedy S Shaffer J Brand J Nicholson R Rolph M Halter E Torres O Masnyk-Bailey |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Calvert Cliffs - IR 05000317/2012004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Calvert Cliffs) @ 2012Q3
Self-Identified List (Calvert Cliffs)
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