05000338/FIN-2009007-02
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Finding | |
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| Title | |
| Description | The inspectors identified a finding having very low safety significance (Green) involving the failure of the licensee to ensure that the control settings for the non-safety related reserve station service transformer (RSST) A replacement load tap changer (LTC) controller installed through design change package (DCP)05-108 were correctly implemented such that the LTC could respond as expected and credited across the range of design conditions. The licensee declared the RSST inoperable and implemented a change to the controller settings in compliance with design, and is tracking further actions under CR358215. The inspectors concluded that the finding was more than minor in that it is associated with the reactor safety mitigating systems cornerstone attribute of equipment performance and affects the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, failure of the LTC to operate, as credited, due to incorrect LTC controller set points or inadequate control voltages, would have caused the 4kV safety related buses to prematurely disconnect from offsite power during a design basis event. The finding is of very low safety significance as it did not result in an actual loss of safety function. Further, this finding did not constitute a violation of NRC requirements as the RSST A is a non-safety related component. The team also evaluated the finding for cross-cutting aspects and determined it to involve a failure to ensure adequately trained resources were available to design, check, and review complex digital controllers and their settings, and so involved the human performance (H) resources component cross cutting aspect (H.2.(c) |
| Site: | North Anna  |
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| Report | IR 05000338/2009007 Section 1R21 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | A Alen R Moore C Baron R Lewis J Hamman G Nicely B Desai J Eargle |
| CCA | H.7, Documentation |
| INPO aspect | WP.3 |
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Finding - North Anna - IR 05000338/2009007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (North Anna) @ 2009Q4
Self-Identified List (North Anna)
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