05000461/FIN-2010003-05
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Finding | |
|---|---|
| Title | Failure to Follow Procedure Resulting in Gate Seal Leakage |
| Description | A finding of very low safety significance with an associated NCV of 10 CFR 50, Appendix B, Criteria V, Instructions, Procedures, and Drawings, was self-revealed on January 29, 2010, when the dryer cavity gate seal depressurized during the performance of the containment and reactor vessel isolation functional surveillance procedure. When the seal lost pressure, approximately 46,500 gallons of water leaked from the dryer cavity pool into the reactor cavity. In response to the event, the licensee ensured all personnel were out of the reactor cavity, entered its radioactive spill off-normal procedure, and re-established air pressure to the dryer cavity gate seal. Subsequent investigation revealed that during the gate seal inflation procedure, the proper valve operation sequence was not followed. As a corrective action, the licensee revised many of its procedures and included a special brief to the refueling outage preparation for Reactor Services personnel. The finding was of more than minor significance because the licensee‟s failure to correctly install the upper containment dryer cavity gate could be reasonably viewed as a precursor to a significant event and, if left uncorrected, would potentially lead to a more significant safety concern (i.e., increased dose or personnel contamination). In addition, the finding was similar to Example 4c in IMC 0612, Power Reactor Inspection Reports, Appendix E, Examples of Minor Issues, in that, data recorded during installation of the dryer cavity gate seal was incorrect and resulted in backup air bottle supply pressure left outside the acceptable range. Because the dryer cavity gate seal is intended to contain highly radioactive fluids within containment, which supports the radiological barrier functions to protect plant workers and the public following serious transients or accidents, the inspectors concluded that this issue was associated with the Barrier Integrity Cornerstone. Although this event resulted in a loss of inventory from the dryer cavity pool and partial flooding of the lower reactor cavity and drywell, it was determined to be of very low safety significance because there was no loss of inventory from the reactor vessel and it could not result in the loss of reactor coolant system level instrumentation. The inspectors concluded that this finding affected the cross-cutting area of human performance. The licensee\'s Root Cause Report described the root cause as the maintenance craftsman performed steps out of sequence and failed to comply with the procedure. Therefore, as concluded by the Root Cause, in this instance, the licensee did not effectively communicate expectations regarding procedural compliance and, as a result, the Reactor Services maintenance craftsman did not correctly follow the procedure by performing steps out of sequence and restoring a system to service that was incorrectly aligned. (IMC 0310 H.4(b)) |
| Site: | Clinton  |
|---|---|
| Report | IR 05000461/2010003 Section 4OA2 |
| Date counted | Jun 30, 2010 (2010Q2) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | B Kemker D Lords D Melendez Colon E Coffman J Cassidy M Mitchell M Ring R Russell S Mischke |
| CCA | H.8, Procedure Adherence |
| INPO aspect | WP.4 |
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Finding - Clinton - IR 05000461/2010003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Clinton) @ 2010Q2
Self-Identified List (Clinton)
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