05000454/FIN-2011004-01
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Finding | |
|---|---|
| Title | Failure to Identify Elevated Risk Status |
| Description | The inspectors identified a finding of very low safety significance (Green) and an associated NCV of 10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear power Plants, when licensee personnel failed to accurately assess plant risk during maintenance activities. The inspectors determined that the licensee failed to identify and take actions required to address an increase in risk when the Unit 2 Component Cooling Water (CC) heat exchanger was removed from service. Specifically, for 0.6 days the Unit 2 CC heat exchanger was removed from service and the plant remained in a Green risk status although the licensee\'s maintenance risk management procedure prescribed that a Yellow risk status be entered and that certain Risk Management Actions (RMAs) be taken. Upon identification and notification by the NRC inspectors, licensee personnel revised the plant risk status from Green to Yellow and took the appropriate RMAs. The issue was entered into the licensees corrective action program as Issue Report (IR) 1262639. The performance deficiency was determined to be more than minor because it was associated with the Human Performance attribute of the Mitigating Systems Cornerstone and affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). The performance deficiency was also determined to be more than minor because the finding was similar to IMC 0609, Appendix E, Example 7.e, and resulted in actual plant risk being in a higher risk category established by the licensee than had been previously declared. The Byron Standardized Plant Analysis Risk (SPAR) model Version 8.18 and SAPHIRE model Version 8.0.7.17 was used to calculate an Incremental Core Damage Probability Deficit (ICDPD) for the condition of the Unit 2 CC heat exchanger being unavailable for 0.6 days. The result was an ICDPD of less than 5E-7. Based on the analysis, the finding was determined to be of very low safety significance (Green). This finding had a cross-cutting aspect in the Work Control component of the Human Performance cross-cutting area [H.3.(a)] because the licensee failed to appropriately incorporate risk insights when the Unit 2 CC heat exchanger was removed from service. |
| Site: | Byron  |
|---|---|
| Report | IR 05000454/2011004 Section 1R13 |
| Date counted | Sep 30, 2011 (2011Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | E Duncan J Gilliam J Nance R Ng C Thompson B Bartlett J Robbins J Cassidy T Bilik B Metrow D Jones |
| CCA | H.5, Work Management |
| INPO aspect | WP.1 |
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Finding - Byron - IR 05000454/2011004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Byron) @ 2011Q3
Self-Identified List (Byron)
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