05000244/FIN-2010009-01
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Finding | |
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| Title | Inadequate Evaluation of Breaker Coordination for Amptector Type LSG Trip Unit Discriminator Feature |
| Description | The team identified a finding of very low safety significance involving a non-cited violation (NCV) of 10 CFR 50, Appendix B, Criterion III, Design Control. Specifically, Constellation had not verified the adequacy of their design with respect to the impact of the installed Amptector type LSG trip unit discriminator feature on breaker coordination. The discriminator circuit design had not been evaluated to ensure the 480V load center bus motor control center (MCC) feeder breakers would maintain coordination and be capable of maintaining power to downstream safety-related components in response to design basis events such as seismic or steam line break transients. Constellation entered the issue into their corrective action program to evaluate the adequacy of their design and ensure the feeder breakers remained operable. The finding was determined to be more than minor because the finding was associated with the Mitigating Systems Cornerstone attribute of design control and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of the 480V busses to respond to initiating events to prevent undesirable consequences. The team evaluated the finding in accordance with Inspection Manual Chapter (IMC) 0609, Significance Determination Process, Attachment 0609.04, Phase 1-lnitial Screening and Characterization of Findings, Table 4a for the Mitigating Systems Cornerstone. The team determined the finding was of very low safety significance because it was a design deficiency confirmed not to result in a loss of operability. The team did not identify a cross cutting aspect with this finding because this was an old design issue and therefore was not reflective of current performance. |
| Site: | Ginna  |
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| Report | IR 05000244/2010009 Section 1R21 |
| Date counted | Dec 31, 2010 (2010Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | C Baron J Schoppy F Arner S Kobylarz M Balazik L Doerflein A Rao |
| INPO aspect | |
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Finding - Ginna - IR 05000244/2010009 | |||||||||||||||||||||||||||||||||
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Finding List (Ginna) @ 2010Q4
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