05000327/FIN-2013007-03
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Finding | |
|---|---|
| Title | Failure to Properly Translate the Design and Licensing Bases for the 125 VDC System Into Design Calculations |
| Description | The team identified a non-cited violation of 10 CFR 50, Appendix B, Criterion III, Design Control, for the licensees failure to properly translate the design and licensing bases for the 125 VDC system into design calculations. The licensee inappropriately credited the battery chargers for voltage support during accident scenarios in their voltage drop calculations, and failed to include vital inverters in the battery load profile. This was a performance deficiency. In response to the teams inquiries, the licensee initiated PER 758465 that provided reasonable expectation of operability by demonstrating that the required voltages would be available. This was based on interpolation of the vendor battery curves considering the maximum loading on the battery for the applicable portions of the duty cycle. This performance deficiency was determined to be more than minor because it affected 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. Specifically, the licensee failed to properly evaluate the 125 VDC system under accident conditions to ensure the capability and availability of 125V control circuits to operate during design basis events. The team used Inspection Manual Chapter 0609, Significance Determination Process, Attachment 4, Initial Characterization of Findings, and Appendix A, The Significance Determination Process for Findings At-Power, and determined that the finding was of very low safety significance (Green) because the finding was not a design deficiency resulting in the loss of functionality or operability. A cross-cutting aspect was not identified because this performance deficiency was not indicative of present licensee performance. |
| Site: | Sequoyah  |
|---|---|
| Report | IR 05000327/2013007 Section 1R21 |
| Date counted | Sep 30, 2013 (2013Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | D Mas G Skinner N Coovert R Nease R Patterson S Walker V Ferrarini |
| Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
| INPO aspect | |
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Finding - Sequoyah - IR 05000327/2013007 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Sequoyah) @ 2013Q3
Self-Identified List (Sequoyah)
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