05000275/FIN-2009005-01
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Finding | |
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| Title | Less Than Adequate Work Planning Resulted in the Release of Two Gas Decay Tanks |
| Description | The inspectors identified a self-revealing noncited violation of Technical Specification 5.4.1, Procedures, after Pacific Gas and Electric inadvertently released the contents of two gas decay tanks into the auxiliary building. Gas Decay Tank 2-2 was in purge mode. On October 11, 2009, plant operators were implementing an equipment control clearance to drain the emergency core cooling systems. A second group of operators were implementing a core offload master clearance. The parallel implementation of both equipment clearances resulted in Gas Decay Tank 2-2 to be vented into the auxiliary building. The auxiliary building operator received a low gas header pressure alarm after the pressure dropped to 15 psig. Per procedure, the operator aligned Gas Decay Tank 2-3 to purge mode. As a result, the second gas decay tank was released into the auxiliary building through the open vent path. The inspectors concluded that the radiological consequence of the event did not result in a potential for overexposure because the reactor had been shutdown since October 3, 2009. The inspectors concluded that the failure to properly implement the core offload master equipment control clearance was a performance deficiency. The finding is more than minor because the performance deficiency could be reasonably viewed as a precursor to a significant event. The inspectors determined the finding to have very low safety significance because the performance deficiency only represented a degradation of the auxiliary building radiological barrier function. This finding has a crosscutting aspect in the area of human performance associated with the work control component because the licensee did not adequately plan and coordinate the two clearance activities or fully consider the impact the work had on different job activities and the need for the two work groups to maintain interfaces H.3(b) |
| Site: | Diablo Canyon  |
|---|---|
| Report | IR 05000275/2009005 Section 1R20 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.2 |
| Inspectors (proximate) | G Guerra M Brown M Peck G George G Miller S Makor D Graves N Greene |
| CCA | H.9, Training |
| INPO aspect | CL.4 |
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Finding - Diablo Canyon - IR 05000275/2009005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Diablo Canyon) @ 2009Q4
Self-Identified List (Diablo Canyon)
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