05000400/FIN-2010003-02
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Finding | |
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| Title | Reactor Trip due to Failing to Properly Assemble an Oil Filter in the Hydrogen Seal Oil System |
| Description | A self-revealing Green finding was identified for the licensees failure to follow Work Control Management procedure WCM-006, Graded Approach to Planning and Scheduling, which has requirements that would have ensured the proper rebuild of the oil filter assembly in the hydrogen seal oil (HSO) system. Specifically, this resulted in inadequate maintenance on the filter assembly which caused the handle of the assembly to eject during power operations, causing an oil spill which necessitated a manual reactor trip. The licensee entered this issue into the CAP as Action Request (AR) #366174. The licensee took corrective action to replace the oil filter assembly, as well as clean and replace the spilled oil. Additionally, the licensee reviewed both completed and upcoming work orders to verify they were properly classified based upon potential impact on plant operations. The licensees failure to follow WCM-006 requirements which resulted in the improper rebuild of the oil filter assembly in the HSO system was identified as a performance deficiency. The finding was determined to be more than minor because it was associated with the procedure quality attribute of the initiating events cornerstone and affected the cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions. Specifically, the performance deficiency resulted in an initiating event causing a manual reactor trip and the possibility of an oil fire in the vicinity of the offsite power electrical supply ducts. Using IMC 0609, Significance Determination Process, Phase 1 Worksheet, the inspectors concluded that a Phase 2 evaluation was required since the finding contributed to both the likelihood of a reactor trip and the likelihood that mitigating systems would not have been available. This conclusion was based upon the potential for the spilled oil to ignite in a location that could have challenged the offsite electrical power supply bus ducts following the reactor trip. A regional Senior Reactor Analyst completed a Phase 3 evaluation under the Significance Determination Process. The performance deficiency was characterized as of very low safety significance (Green) based upon the results of this evaluation. The dominant accident sequence involved the postulation of oil igniting in the spill zone. Once ignited, suppression efforts were unsuccessful, causing the loss of the turbine building and a loss of offsite power. Given this damage state, recovery of offsite power was not considered credible. Subsequently, it was postulated that the emergency diesel generators failed which ultimately led to a loss of core cooling and core damage. The finding has a cross cutting aspect of Work Planning, as described in the Work Control component of the Human Performance cross-cutting area because the failure to correctly classify the work package as Quality Critical resulted in not correctly mitigating the risk associated with working on this equipment by including additional guidance to assist the technicians in completing the work successfully (H.3(a)) (Section 4OA3). |
| Site: | Harris  |
|---|---|
| Report | IR 05000400/2010003 Section 4OA3 |
| Date counted | Jun 30, 2010 (2010Q2) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | R Hamilton J Austin R Musser C Fletcher P Lessard |
| CCA | H.5, Work Management |
| INPO aspect | WP.1 |
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Finding - Harris - IR 05000400/2010003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Harris) @ 2010Q2
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