05000528/FIN-2011005-03
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Finding | |
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| Title | Failure of Unit 1 Reactor Coolant Pump 2A Motor Junction Box Due to Inadequate Maintenance |
| Description | The inspectors reviewed a self-revealing finding that occurred during maintenance associated with the Unit 1 reactor coolant pump 2A 13.8 kilovolt motor termination enclosure. Specifically, work instructions were inadequate to ensure the enclosure maintained the highest degree of availability and reliability as required by Procedure 30DP-0AP01, Maintenance Work Order Writers Guide. As a result, on October 8, 2011, water leakage from an open nuclear cooling system vent valve entered the enclosure, resulting in a ground fault on the energized 13.8 kilovolt electrical conductors, explosion inside the enclosure, and subsequent declaration of an Unusual Event. The licensee replaced the enclosure and satisfactorily retested reactor coolant pump 2A. The licensee entered this issue into the corrective action program as Condition Report Disposition Request 3905265 and has not completed all corrective actions. The failure of the licensee to provide adequate work instructions to maintain the Unit 1 reactor coolant pump 2A motor termination enclosure to the highest degree of availability and reliability was a performance deficiency. The performance deficiency was more than minor, and therefore a finding, because if left uncorrected, it could lead to a more significant safety concern. Specifically, had the event occurred while the unit was in full power operations, a significant plant transient due to a reactor trip and loss of forced circulation could have occurred. Using Inspection Manual Chapter 0609, Appendix G, Shutdown Operations Significance Determination Process, the inspectors concluded that the finding is of very low safety significance (Green) because it did not require a quantitative assessment. This finding had a cross-cutting aspect in the area of problem identification and resolution associated with the operating experience component because the licensee failed to implement and institutionalize internal operating experience through changes in station work instructions related to RCP motor termination enclosures. Specifically, the licensee has experienced previous issues with water penetration in electrical enclosures and missing seals, and maintenance personnel have consistently had difficulty restoring the electrical terminations due to various factors. This internal operating experience was not incorporated into revised work instructions |
| Site: | Palo Verde  |
|---|---|
| Report | IR 05000528/2011005 Section 4OA3 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | L Ricketson G Guerra R Lantz M Brown B Baca D Allen J Melfi B Parks A Fairbanks E Uribe M Baquera D Reinert S Hedger |
| CCA | P.5, Operating Experience |
| INPO aspect | CL.1 |
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Finding - Palo Verde - IR 05000528/2011005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Palo Verde) @ 2011Q4
Self-Identified List (Palo Verde)
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