05000335/FIN-2009006-05
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Finding | |
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| Title | Failure to Translate Design Basis Specifications to Prevent Single Failure of CCW |
| Description | The team identified an AV of 10 CFR 50, Appendix B, Criterion III, Design Control, for the licensees failure to identify that the CCW system met its license specifications related to common cause failure vulnerabilities. Specifically, a nonsafety system failure (i.e. waste gas compressor aftercoolers affecting both units, or containment IA compressors affecting Unit 1 only) could result in a common cause failure of both trains of a safety system (i.e. CCW system). The issue was entered into the licensees corrective action program as CR 2009-22929 with actions to evaluate the past operability of the CCW system during the air intrusion event. Licensee corrective actions included isolating the CCW system from the containment IA compressors. The finding was determined to be more than minor because if left uncorrected, it could affect the availability, reliability and capability of a safety system to perform its intended safety function. Specifically, with this vulnerability, a failure of the waste gas aftercooler (both units) or a failure of the containment IA compressors (Unit 1 only) could cause air intrusion into the CCW system and lead to a loss of CCW event, therefore, failing to ensure that adequate cooling would be available or maintained to essential equipment used to mitigate design bases accidents. The finding was assessed for significance in accordance with NRC Manual Chapter 0609, using the Phase I and Phase II SDP worksheets for mitigating systems. It was determined that a Phase III analysis was required since this finding represented a potential loss of safety system function for multiple trains which was not addressed by the Phase II pre-solved tables/worksheets. Based on the Phase III SDP, the finding was preliminarily determined to be greater than Green. The team reviewed the finding for cross-cutting aspect and concluded that this finding did not have an associated cross-cutting aspect because the design of the CCW system was established in an original plant design, and therefore, was not representative of current licensee performance |
| Site: | Saint Lucie  |
|---|---|
| Report | IR 05000335/2009006 Section 4OA5 |
| Date counted | Sep 30, 2009 (2009Q3) |
| Type: | AV: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | B Desai C Even J Hamman L Slack M Shylamberg N Greca R Moore R Taylor S Roseb Desaij Hamman M Shylamberg N Greca R Moore R Taylor S Rose |
| INPO aspect | |
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Finding - Saint Lucie - IR 05000335/2009006 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Saint Lucie) @ 2009Q3
Self-Identified List (Saint Lucie)
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