05000317/FIN-2011005-03
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Finding | |
|---|---|
| Title | Turbine Building Siding Failure below Design Specification |
| Description | A self-revealing finding of very low safety significance was identified because Constellation did not ensure the turbine building (TB) siding was installed in accordance with design requirements of ES-005, Civil and Structural Design Criteria. This resulted in wind induced TB siding failures significantly below design wind speeds. Consequently, Unit 1 experienced an automatic trip from 100 percent power due to a phase to-phase short circuit on the main transformer when the main transformer high voltage lines were struck by dislodged TB siding caused by high winds associated with Hurricane lrene. The inspectors determined that Constellation missed multiple opportunities to identify the TB siding installation deficiencies following several high wind events and through the use of operating experience (OE). Immediate corrective actions included entering this issue into their CAP and restricting personnel travel in outside areas with sustained wind speed greater than 40 mph until the TB corner siding on all corners has been verified to be properly installed. Other corrective actions include testing and inspection of the main transformer, repairs to the \'B\' and \'C\' phase high line drops to the main transformer, temporary repairs to the TB siding and development of new installation requirements which meet the design requirements of the TB siding corners. In addition, Constellation\'s planned corrective actions include inspecting all building siding inside the protective area to identify other possible deficiencies. The finding is more than minor because it is associated with the protection against external factors attribute (wind and grid stability) of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during power operations. Specifically, the finding resulted in a reactor trip of Unit 1. The inspectors determined that the finding is of very low safety significance because the finding did not contribute to both the likelihood of a reactor trip and the likelihood that mitigation equipment or functions would not be available. This finding has a cross-cutting aspect in the area of problem identification and resolution, OE, because Constellation did not use OE information and internally generated lessons learned, to support plant safety and implement changes to station processes, procedures, equipment, and training programs. Specifically, Constellation did not implement and institutionalize OE associated with siding failures through changes to station processes, procedures, and equipment, and training programs (P.2.b per IMC 0310) |
| Site: | Calvert Cliffs  |
|---|---|
| Report | IR 05000317/2011005 Section 4OA3 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | D Silk S Pindale G Dentel P Presby S Kennedy D Kern R Rolph J Hawkins E Torres K Cronk M Jennerich |
| CCA | P.5, Operating Experience |
| INPO aspect | CL.1 |
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Finding - Calvert Cliffs - IR 05000317/2011005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Calvert Cliffs) @ 2011Q4
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