05000456/FIN-2014005-02
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Finding | |
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Title | Failure to Correct Undersize Essential Service Water Pump Bearing Casing Drain Line Resulted in System Inoperability |
Description | A finding of very low safety significance (Green) and an associated NCV of 10 CFR 50, Appendix B, Criterion III, Design Control was self-revealed following the licensees failure to design the 1B essential service water (SX) pump inboard bearing casing drain line in a manner that ensured pump operability. Specifically, the licensee had re-designed the 1B SX pump inboard bearing drain line by replacing a hard pipe drain with a flexible hose drain line consisting of fittings of a smaller diameter when compared to the previous hard pipe drain line. This design change resulted in unplanned 1B SX pump inoperability and required operator action to secure the pump to preclude pump damage. The licensee entered this issue into the CAP as IR 2413941. Corrective actions included restoring adequate drain flow by replacing the flexible hose drain line with a hard pipe of a larger diameter. The performance deficiency was of more than minor safety significance because the issue was associated with the Equipment Performance attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the failure t
adequately design the 1B SX pump inboard bearing housing drain line resulted in an inoperable 1B SX pump. The finding was of very low safety significance (Green) because the inspector answered No to all of the associated Mitigating Systems screening questions within IMC 0609, Attachment 4, Initial Characterization of Findings. The finding is associated with the cross-cutting area of Problem Identification and Resolution with an aspect of Evaluation because the licensee did not thoroughl evaluate plant design in a manner commensurate with the safety significance. Specifically, the licensee inappropriately evaluated the design of the 1B SX pump inboard bearing housing drain line after identifying that the drain line size was the contributing cause for a loss of oil inventory in December 2013 (P.2). |
Site: | Braidwood |
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Report | IR 05000456/2014005 Section 4OA2 |
Date counted | Dec 31, 2014 (2014Q4) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | Self-revealing |
Inspection Procedure: | IP 71152 |
Inspectors (proximate) | B Boston B Palagi D Betancourt J Benjamin J Ellegood J Mcghee K Barclay M Holmberg M Perry R Jickling |
Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
CCA | P.2, Evaluation |
INPO aspect | PI.2 |
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Finding - Braidwood - IR 05000456/2014005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2014Q4
Self-Identified List (Braidwood)
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