05000247/FIN-2010002-03
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Finding | |
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| Title | Improper Generrex Isolation Caused Reactor Trip |
| Description | A self-revealing finding of very low safety significance was identified because Entergy personnel did not establish procedures that were appropriate to the task, and personnel did not adequately implement the procedures that existed for isolating the generator exciter system on the main generator. Specifically, on January 11, 2010, Entergy personnel did not properly isolate one rectifier exciter bank on the exciter system of the main generator while repairing a leak in the associated cooling water line. Entergy staff did not ensure that the procedural direction was adequate to ensure that the workers could recognize when the exciter rectifier disconnect switches were in the fully open position. In addition, Entergy supervisors did not stop the maintenance in the face of uncertainty when presented with several indications that the 24 exciter rectifier bank had not been isolated, including detecting unexpected voltage in the 24 exciter rectifier cabinet and a high temperature alarm associated with the exciter rectifier. As a result, the rectifier bank was not properly isolated electrically while the cooling water to the rectifier was isolated. This resulted in overheating the exciter bank control circuits which caused a main turbine trip and a reactor trip. This finding is more than minor because the performance deficiencies caused a reactor trip. The finding is associated with both the procedure quality and human performance attributes of the Initiating Events cornerstone and affected the cornerstone objective of limiting the likelihood of those events that upset plant stability and challenge critical safety functions during power operations. The inspectors performed a Phase 1screening in accordance with Inspection Manual Chapter (IMC) 0609 \"Significance Determination Process (SOP)\" and determined that the finding is of very low safety significance (Green) because it did not contribute to the likelihood that mitigation equipment or functions would not be available. The finding has a cross-cutting aspect in the area of human performance related to decision making. Entergy personnel did not make safety-significant or risk significant decisions using a systematic process, especially when faced with uncertain or unexpected plant conditions, to ensure safety is maintained (H.1.a). |
| Site: | Indian Point  |
|---|---|
| Report | IR 05000247/2010002 Section 4OA7 |
| Date counted | Mar 31, 2010 (2010Q1) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | |
| Inspectors (proximate) | B Haagensen E Gray E Keighley J Noggle J Schoppy M Gray O Ayegbiso S Barr |
| CCA | H.13, Consistent Process |
| INPO aspect | DM.1 |
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Finding - Indian Point - IR 05000247/2010002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Indian Point) @ 2010Q1
Self-Identified List (Indian Point)
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