05000331/FIN-2014008-02
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Finding | |
|---|---|
| Title | Failure to Verify Startup Transformer Neutral Grounding Resistor Design Assumption |
| Description | The inspectors identified a finding having very low safety significance (Green) in that, the licensee did not adequately ensure the operation of the Startup Transformer Neutral Grounding Resistors was within the design assumptions used in the calculation of the essential 4160V system ground overcurrent relay trip settings. The licensee entered this finding into their Corrective Action Program and included the requirement for measurement of the neutral grounding resistor in their next Startup Transformer preventive maintenance work order, scheduled for September 2014. The inspectors determined the performance deficiency was more than minor because if left uncorrected, the performance deficiency had the potential to lead to a more significant safety concern. Specifically, had the neutral resistors developed either a short or an open circuit, the 4160V essential emergency loads would have been subject to un-analyzed operating condition and selective breaker tripping could not be assured. This would have increased the likelihood of events that upset plant stability and affected the availability and reliability of the preferred AC power supply. The inspectors determined the finding was of very low safety significance (Green) because it did not cause a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition. The inspectors did not identify a cross-cutting aspect associated with this finding because the finding was not representative of the licensees current performance. |
| Site: | Duane Arnold  |
|---|---|
| Report | IR 05000331/2014008 Section 1R21 |
| Date counted | Sep 30, 2014 (2014Q3) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | A Dahbur A Stone B Jose C Edwards J Braisted J Chiloyan N Valos |
| INPO aspect | |
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Finding - Duane Arnold - IR 05000331/2014008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Duane Arnold) @ 2014Q3
Self-Identified List (Duane Arnold)
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