05000313/FIN-2011006-01
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Failure to Resolve Adverse Conditions in 120 Volt Vital Inverters in a Timely Manner |
| Description | The team identified a non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, because the licensee did not promptly identify and correct a condition adverse to quality that affected static uninterruptible power supply inverters used to power vital and safety related loads. Specifically, the licensee did not identify and correct an issue with undersized constant voltage transformers installed in safety-related 120-volt alternate current inverters. As a result, when a constant voltage transformer in one of the inverters became saturated from a voltage spike or electrical malfunction, it would impact an entire train of inverters. The licensee entered this issue into their corrective action program for resolution as CR-ANO-C-2011-0440. The immediate corrective actions following the additional failures included installation of direct current fuses. The planned corrective actions included installation of a modification to install blocking diodes in the 125 volt direct current input of each vital inverter to prevent faults or transients from adversely affecting the other inverters connected to the same bus. This finding is greater than minor because it is associated with the design and equipment performance attributes of the Mitigating System cornerstone and affects the cornerstone objective to ensure the availability and reliability of safety-related inverters that respond to initiating events to prevent undesirable consequences in that these inverters supply power to vital and safety related loads. The inspectors evaluated the significance of this finding using Phase 1 of the IMe 0609, Appendix A, Significance Determination of Reactor Inspection Findings for At-Power Situations given the importance of the system and the fact that this condition affected an entire train of safety-related inverters due to a voltage spike or electrical malfunction. The inspectors determined that the finding was of very low safety significance (Green) because it is not a qualification deficiency, did not represent a loss of a safety function of a system or a single train greater than its Technical Specification completion time, and did not screen as potentially risk significant due to external events. The inspectors did not assign a crosscutting aspect because the finding is not reflective of current performance (Section 40A2.S). |
| Site: | Arkansas Nuclear  |
|---|---|
| Report | IR 05000313/2011006 Section 4OA2 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | G Tutak I Anchondo M Davis M Hay W Schaup |
| INPO aspect | |
| ' | |
Finding - Arkansas Nuclear - IR 05000313/2011006 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Arkansas Nuclear) @ 2011Q1
Self-Identified List (Arkansas Nuclear)
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||