05000263/FIN-2009007-01
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Finding | |
|---|---|
| Title | Calculation Errors Associated With the Pneumatic Pressure Requirements for the Inboard MSIVs |
| Description | The inspectors identified an NCV of 10 CFR Part 50, Appendix B, Criterion III, Design Control, having very low safety-significance for the failure to incorporate the actual physical configuration of the inboard main steam isolation valves (MSIVs) and the correct pneumatic system pressure drop into the pneumatic pressure requirement calculation for the inboard MSIVs. Specifically, the licensee failed to adjust the actuator moving part weight to reflect that the actuator was offset by 45 degrees instead of being mounted vertically and to correctly compute the system pressure drop. This finding was entered into the licensees corrective action program and a preliminary calculation performed by the licensee concluded that the valves were operable. The finding was more than minor because it was associated with the Barrier Integrity cornerstone attribute of structures, systems, components, and barrier performance, and affected the cornerstone objective of providing reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents or events. This finding is of very low safety-significance (Green) because there was no actual barrier degradation. The inspectors did not identify a cross-cutting aspect associated with this finding because this was a legacy design issue and therefore was not reflective of current performance. |
| Site: | Monticello  |
|---|---|
| Report | IR 05000263/2009007 Section 1R21 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | A Dunlop A Stone C Brown H Campbell J Bozga L Jones M Munir N Feliz Adomo S Kobylarz |
| INPO aspect | |
| Finding closed by | |
| IR 05000263/2009007 (6 January 2010) | |
| ' | |
Finding - Monticello - IR 05000263/2009007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Monticello) @ 2009Q4
Self-Identified List (Monticello)
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