05000263/FIN-2012007-03
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Finding | |
|---|---|
| Title | Failure to Maintain the Degraded Voltage Function Time Delay Design |
| Description | The inspectors identified a finding of very low safety significance (Green) and associated Non-Cited Violation (NCV) of 10 CFR Part 50, Appendix B, Criterion III for the licensees failure to translate the actual time delay of the degraded voltage relay scheme under all circumstances into the station procedures and Technical Specifications. Specifically, a modification which introduced a five second time delay to the degraded voltage scheme resulted in inconsistencies in Technical Specification Table 3.3.8.1-1 and functionality of the degraded voltage relay scheme when the safety buses are aligned to Transformer 1AR. The licensee entered this issue into their corrective action program as Action Request 01334146, and removed Transformer 1AR from service to match the design with the Technical Specifications. The finding was more than minor because it affected the Mitigating Systems Cornerstone attribute of Design Control, and affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, there was reasonable doubt as to whether the degraded voltage scheme would perform as required by Technical Specifications during design basis conditions. The finding was considered to be of very low safety significance (Green) since the total degraded voltage protection scheme time delay of 15 seconds was commensurate with the current accident analysis in the Updated Safety Analysis Report (USAR). The inspectors determined there was no cross-cutting aspect associated with this finding because it was not reflective of licensees current performance due to the age of the issue. |
| Site: | Monticello  |
|---|---|
| Report | IR 05000263/2012007 Section 1R21 |
| Date counted | Jun 30, 2012 (2012Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | C Zoia B Jose G Skinner M Jones J Gilliam A Stone N Feliz-Adorno |
| INPO aspect | |
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Finding - Monticello - IR 05000263/2012007 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Monticello) @ 2012Q2
Self-Identified List (Monticello)
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