05000317/FIN-2012005-01
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Finding | |
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Title | Inadequate Work Package Led to Reactor Coolant System Pressure Boundary Leakage |
Description | A self-revealing NCV of technical specification (TS) 3.4.13, Reactor Coolant System (RCS) Operational LEAKAGE, was identified because Constellation failed to restore the RCS to as-designed configuration following replacement of the 11A reactor coolant pump (RCP) differential pressure transmitter isolation valve in 1998, which resulted in operating with RCS pressure boundary leakage, which is prohibited by TS. Specifically, a design required vertical support was missing on the RCP high pressure differential transmitter tubing which created a high cyclic fatigue vulnerability, eventual weld failure at the tube to pipe adapter, and RCS pressure boundary leakage. RCS pressure boundary leakage was first identified in June 2012, due to an increasing trend in RCS leak rate while the plant was operating at power. Immediate corrective actions included entering this issue into the corrective action program (CAP), replacing the tube to pipe adapter, and installing the missing vertical tubing support. Planned corrective actions include establishing a small bore piping inspection program and conducting walkdowns of Unit 1 and Unit 2 RCP differential pressure transmitter sensing lines and similar sensing lines in other systems. The finding is more than minor because it is associated with the design control 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 during shutdown as well as power operations. Specifically, the failure to restore the system to as-designed configuration resulted in a RCS pressure boundary leak. The inspectors evaluated the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings at Power, and determined the finding is of very low safety significance (Green) because the performance deficiency, after a reasonable assessment of degradation, could not result in exceeding the RCS leak rate for a small loss of coolant accident (LOCA) and could not likely affect other systems used to mitigate a LOCA, resulting in a total loss of their function. The finding does not have a cross-cutting aspect since the failure to restore the asdesigned configuration is not indicative of current licensee performance. Constellations current work order planning procedure requires the planner to translate engineering design documents into maintenance work orders while maintaining the design basis of the plant per the configuration program. |
Site: | Calvert Cliffs |
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Report | IR 05000317/2012005 Section 4OA3 |
Date counted | Dec 31, 2012 (2012Q4) |
Type: | NCV: Green |
cornerstone | Initiating Events |
Identified by: | Self-revealing |
Inspection Procedure: | IP 71153 |
Inspectors (proximate) | E Torres G Dentel J Caruso J Laughlin R Barkley R Rolph S Kennedy |
INPO aspect | |
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Finding - Calvert Cliffs - IR 05000317/2012005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Calvert Cliffs) @ 2012Q4
Self-Identified List (Calvert Cliffs)
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