05000382/FIN-2011005-05
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Finding | |
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| Title | Failure to Follow Work Order Instructions to Install a Swagelok Fitting on a Main Feedwater Isolation Valve Tube Connection |
| Description | The inspectors identified a non-cited violation of Technical Specification 6.8.1.a because the licensee did not follow work order instructions to install a pressure gage in an air line used to measure and maintain pressure for the hydraulic accumulators that close the main feedwater isolation valve. Specifically, the licensee did not follow the instructions to assemble and tighten a Swagelok fitting according to the work order. As a result, the fitting failed, preventing the valve from being able to perform its safety-related function. The licensee entered this issue into their corrective action program as CR-WF3-2010-1166 and CR-WF3-2011-7469. The immediate corrective actions included repairing the Swagelok fitting and completing an apparent cause evaluation to determine the nature of the fitting failure and failure to follow procedure. The performance deficiency is more than minor because it is associated with the equipment performance attribute of the Mitigating Systems cornerstone and affects the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The inspector performed the initial significance determination using NRC Inspection Manual 0609, Attachment 0609.04, Phase 1 Initial Screening and Characterization of Findings. The finding screened to a Phase 2 significance determination because it involved a potential loss of one train of safety related equipment for longer than the technical specification allowed outage time. A Region IV senior reactor analyst performed a Phase 2 significance determination and used the pre-solved worksheet from the Risk Informed Inspection Notebook for the Waterford-3 Nuclear Power Plant, Revision 2.01a. However, the main feedwater isolation valves were not included in the pre-solved worksheet and the valves did not appear as components in the Phase 2 significance determination worksheets. The senior reactor analyst performed a Phase 3 significance determination for this issue. The analyst noted that the main feed isolation valves were not a significant contributor to core damage frequency and were not included in the NRCs SPAR model. These valves close to mitigate core overcooling events or to isolate feedwater flow to a ruptured feedwater line inside containment. Overcooling events do not lead to core damage. A ruptured feedwater line could challenge containment integrity, but without core damage there would be no potential for a large early release. If a valve failed to close on demand, the licensee had other means to isolate feedwater flow to a steam generator or into containment. Operators could secure feedwater pumps, close a block valve, or close the main feedwater flow control valves. Accordingly, the contribution to core damage was much less than E-6. As a result, this finding had a very low safety significance (Green). This finding does not have a crosscutting aspect since it is not indicative of current plant performance |
| Site: | Waterford  |
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| Report | IR 05000382/2011005 Section 4OA2 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | L Ricketson G Guerra C Smith P Elkmann M Davis G George L Carson D Allen D Overland B Correll S Hedger N Greene D Bradley |
| INPO aspect | |
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Finding - Waterford - IR 05000382/2011005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Waterford) @ 2011Q4
Self-Identified List (Waterford)
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