05000346/FIN-2013004-04
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Finding | |
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| Title | Operation of the Plant at Power with Reactor Coolant System Pressure Boundary Leakage |
| Description | A self-revealed finding of very low safety significance and an associated noncited violation of TS 3.4.13, Reactor Coolant System (RCS) Operational Leakage, were identified for the licensees failure to fully evaluate a previously identified degraded condition on the first stage seal cavity vent line for RCP 1-2. Specifically, a known high vibration condition associated with this line had caused a pinhole leak on a socket weld on the line that was repaired in June of 2012. However, the licensee's root cause evaluation and subsequent repair efforts for that leak failed to adequately address other welds on that vent line that were also subjected to the same high vibration levels, such that following an unplanned reactor trip another small RCS pressure boundary leak was discovered on a different socket weld on the same line on July 1, 2013. This finding was determined to be of more than minor significance because it was associated with cornerstone attribute of equipment performance and adversely affected the cornerstone objective: To limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Since the finding was not related to pressurized thermal shock and only involved an RCS barrier (leakage) issue, it was evaluated under the Initiating Events Cornerstone and determined it to be of very low safety significance because:After a reasonable assessment of degradation, the inspectors determined that due to the small size of the RCP 1-2 first stage seal cavity vent line that the finding could not result in exceeding the RCS leak rate for a small loss of coolant accident (LOCA); and After a reasonable assessment of degradation, the inspectors determined that the finding could not have likely affected other systems used to mitigate a LOCA resulting in a total loss of their function (e.g., Interfacing System LOCA, etc.). The finding had a cross-cutting aspect in the area of problem identification and resolution (PI&R), corrective action program (CAP) component, because the licensee had failed to thoroughly evaluate the event in June of 2012 such that the resolution addressed causes and extent of conditions. |
| Site: | Davis Besse  |
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| Report | IR 05000346/2013004 Section 4OA3 |
| Date counted | Sep 30, 2013 (2013Q3) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | A Dunlop J Neurauter P Pelke D Kimble T Briley J Steffes |
| Violation of: | Technical Specification |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Davis Besse - IR 05000346/2013004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2013Q3
Self-Identified List (Davis Besse)
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