05000338/FIN-2011011-07
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Finding | |
|---|---|
| Title | Safety Related Instrumentation Anomalies |
| Description | During the post event review, the licensee identified some unexpected anomalies that occurred during the event, related to safety related instrumentation. The team independently reviewed event recorders, plant records, and interviewed personnel to determine whether the licensee had identified and appropriately addressed any observed equipment performance issues. The team found that some plant instrumentation anomalies warranted follow-up. The team identified one URI described in this section. The licensee had identified and recorded a number of instrument anomalies, many of which were attributed to the earthquake. Some examples of instruments affected included: Minor perturbations in Units 1 and 2 Safety Injection Accumulator and Refueling Water Storage Tank (RWST) levels Nuclear Instrumentation Loop 1C High Delta Temperature Hi-Hi Steam Generator Level RWST Chemical Addition Tank Temperature The team questioned whether these anomalies were indications of actual parameter changes in level, pressure, etc. due to the seismic event or false indications that were seismically induced. If the indications were seismically induced, the team inquired whether the instrument exceeded their seismic qualification or whether the seismic qualification of the instrument was appropriate. The licensee planned to determine the most likely cause of the anomalies through their root cause assessment of the August 23, 2011 seismic event. Because some of the anomalies identified with the safety related instrumentation could have been seismically induced and thus potentially calls into question the seismic qualification of the instruments, additional review by the NRC will be needed to determine whether this issue represented a performance deficiency. An unresolved item will be opened pending completion of this review. The issue will be identified as URI 05000338, 339/2011011-07: Safety Related Instrumentation Anomalies. |
| Site: | North Anna  |
|---|---|
| Report | IR 05000338/2011011 Section 4OA5 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 93800 |
| Inspectors (proximate) | G Kolcum L Suggs M Chakravorty M Franke R Jackson S Park S Walker V Mccree Y Lie Leag Kolcum G Mccoy L Lake M Yoo R Clagg |
| INPO aspect | |
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Finding - North Anna - IR 05000338/2011011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (North Anna) @ 2011Q4
Self-Identified List (North Anna)
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