05000461/FIN-2011008-01
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Finding | |
|---|---|
| Title | Failure to Account for Cable Resistance in Operability Determinations |
| Description | The inspectors identified a finding of very low safety significance with an associated NCV of 10 CFR Part 50, Appendix B, Criterion III, Design Control, related to calculational errors found in the licensees operability determination. Specifically, on four separate operability determinations, the licensee failed to account for the cable resistance when determining the maximum allowable contact resistance associated with the second level undervoltage (UV) relays for the 4.16 kV Buses. The licensee entered this violation into its CAP as Action Requests (ARs) 1226340 and 1224313 and performed a preliminary calculation which determined that the error reduced the available margin in the circuit resistance but did not change the overall conclusions for the past operability calls made for the four different occasions. The inspectors determined that this finding was more than minor because it was associated with the Mitigating Systems Cornerstone attribute of design control and adversely affected the cornerstone objective of ensuring availability and reliability of systems that respond to initiating events to prevent undesirable consequences. This finding was of very low safety significance (Green) because the licensee was able to demonstrate that the operability calls that were previously made relating to the second level UV relays were still valid and acceptable. The inspectors concluded that this finding affected the cross-cutting aspect of human performance. Specifically, the licensee failed to use conservative assumptions in decision making related to immediate operability determinations of conditions adverse to quality. |
| Site: | Clinton  |
|---|---|
| Report | IR 05000461/2011008 Section 4OA2 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | A Dahbur R Orlikowski M Ring S Mischke D Lords A Shaikh |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
| ' | |
Finding - Clinton - IR 05000461/2011008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Clinton) @ 2011Q2
Self-Identified List (Clinton)
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