05000293/FIN-2011007-01
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Finding | |
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| Title | Inadequate Evaluation of the Adequacy of the 4160 Volt Emergency Bus 95% Voltage Alarm and Load Shed Relay Design |
| Description | The team identified a finding of very low safety significance involving a non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion III, Design Control, because Entergy had not verified the adequacy of the 4160 volt emergency bus 95% voltage alarm/load shed relay design regarding the potential for multiple starts of the salt service water (SSW) and reactor building closed cooling water (RBCCW) pump motors. Additionally, Entergy had not verified the adequacy of design with respect to the ability of the SSW pump motors to restart following a load shed of the motors without tripping the motor control center (MCC) thermal overload (TOl) relays at design basis degraded voltage conditions. Entergy entered the issue into their corrective action program and implemented measures to bypass the SSW pump motor TOl relay motor trips based on their initial review of TOl margin. The team determined this to be a conservative action which ensured under all conditions including degraded voltage, that the SSW pump motors would not be inadvertently tripped due to TOl margin concerns. The performance deficiency was determined to be more than minor because it was associated with the design control attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The team evaluated the finding in accordance with IMC 0609, Significance Determination Process, Attachment 0609.04, Phase 1 - Initial Screening and Characterization of findings. The finding was determined to be of very low safety significance because it was a design deficiency confirmed not to result in a loss of operability. This finding was not assigned a cross-cutting aspect because it was a historical design issue not indicative of current performance. |
| Site: | Pilgrim |
|---|---|
| Report | IR 05000293/2011007 Section 1R21 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | J Lilliendahl C Baron J Schoppy F Arner J Brand S Kobylarz L Doerflein |
| INPO aspect | |
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Finding - Pilgrim - IR 05000293/2011007 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Pilgrim) @ 2011Q4
Self-Identified List (Pilgrim)
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