05000346/FIN-2016004-01
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Finding | |
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| Title | Mispositioned Instrument Air Valves Result in Plant Transient |
| Description | A self-revealed finding of very low safety significance was identified for the licensees failure to appropriately follow station procedures for aligning instrument air valves that support main feedwater (MFW) regulating valve operation. Specifically, two instrument air valves were not aligned to their normal operating position following planned maintenance. As a result, the Steam Generator 2 (SG 12) MFW Regulating Valve momentarily closed during routine steam feedwater rupture control system (SFRCS) surveillance testing and caused a plant transient. Corrective actions taken by the licensee, include but are not limited to, performance of an instrument air valve line up to validate no other valves were out of position; performance of SFRCS Actuation Channel 2 testing to verify no other half trips existed on SFRCS Actuation Channel 2 components; a configuration control stand-down with the instrument and control shop; and revisions to procedural guidance to perform additional valve position verification. The finding was of more than minor significance because it was associated with cornerstone attribute of configuration control and adversely affected the cornerstone objective: To limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. The finding was determined to be of very low safety significance because the finding did not cause a reactor scram with the loss of mitigation equipment relied upon to transition the plant from the onset of the scram to a stable shutdown condition (e.g. loss of condenser, loss of feedwater). The inspectors determined that the finding had a cross-cutting aspect in the area of human performance. The inspectors assigned the cross-cutting aspect of Avoid Complacency to the finding because the procedural step to close valve IA1008A was marked as complete but was not performed correctly. Additionally, appropriate human performance error reduction tools were not adequately used to ensure valve manipulations were performed as intended. (H.12) |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2016004 Section 1R12 |
| Date counted | Dec 31, 2016 (2016Q4) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | A Dahbur D Kimble D Mills J Cassidy J Mancuso J Rutkowski J Seymour M Garza P Smagacz R Walton T Briley |
| Violation of: | Pending |
| CCA | H.12, Avoid Complacency |
| INPO aspect | QA.4 |
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Finding - Davis Besse - IR 05000346/2016004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2016Q4
Self-Identified List (Davis Besse)
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