05000289/FIN-2012007-01
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Finding | |
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| Title | Nonconservative Differential Pressure Value used in DHRyLPI Motor Operated Valves Design Analysis |
| Description | The team identified a finding of very low safety significance (Green) involving a non-cited violation of 10 CFR Part 50, Appendix B, Criterion lll, Design Control, because Exelon had not verified the adequacy of their design with respect to ensuring the capability of the emergency core cooling system piggyback mode of operation during sump recirculation in response to postulated small break loss-of-coolant accident (SBLOCA) conditions. Specifically, the decay heat system low pressure injection (LPl) piggyback motor operated valves (DH-V-7AJB) and containment isolation sump valves (DH-V-OA/B) had not been evaluated to ensure they would open against the maximum expected differential pressures assuming the maximum allowable technical specification (TS) backleakage of system pressure isolation valves (PlVs). Exelon entered the issue into their corrective action program to evaluate the current design and ensure the valves required for piggyback operation could be opened in response to SBLOCA scenarios which may require the transfer to the sump recirculation mode of operation. The performance deficiency was determined to be more than minor because it was associated with the design control 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. The team evaluated the finding in accordance with IMC 0609, Significance Determination Process, Attachment 4, Phase 1 - Initial Screening and Characterization of Findings. The finding was determined to be of very low safety significance because it was a design deficiency confirmed not to result in a loss of operability, This finding was not assigned a cross-cutting aspect because it was a historical design issue not indicative of current performance. |
| Site: | Crane  |
|---|---|
| Report | IR 05000289/2012007 Section 1R21 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | J Lilliendahl J Schoppy F Arner J Brand J Nicely L Doerflein C Edwards |
| INPO aspect | |
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Finding - Crane - IR 05000289/2012007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Crane) @ 2012Q1
Self-Identified List (Crane)
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