05000397/FIN-2011004-05
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Finding | |
|---|---|
| Title | Failure to Ensure Main Steam Isolation Valve Setpoint Change is Adequate |
| Description | The inspectors reviewed a self revealing violation of 10 CFR Part 50 Appendix B, Criterion III for the licensee's failure to perform an adequate review of a design modification that changed the isolation logic for the main steam isolation valves from Level 2 to Level 1. This modification inadvertently changed the isolation logic for outboard containment isolation valves located in containment isolation Groups 3 and 4 due to inadequate design reviews. Prior to the modification, the containment isolation Groups 3 and 4 received a half isolation when swapping power supplies in the reactor protection system. After the modification the containment isolation Groups 3 and 4 received a full outboard isolation signal when the reactor protection system A was swapped from its normal to alternate source. The licensee changed half of the isolation logic to be powered from reactor protection system B. This issue was entered into the licensee's corrective action program as Action Request 238830. The finding was more than minor because it affected the design control attribute of the Barrier Integrity Cornerstone objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by events. Since the finding was discovered and corrected while in a shutdown condition, the inspectors evaluated the finding using Manual Chapter 0609, Appendix G, Shutdown Operations Significance Determination Process. The finding was determined to be of very low safety significance (Green) since it was not associated with a finding that degraded the licensee's ability to terminate a leak path or add reactor coolant system inventory when needed, did not significantly degrade the licensee's ability to recover decay heat removal when lost and did not impact a heat removal path to the suppression pool while the vessel head was installed. During the review of the licensee's root cause, the inspectors identified a cross-cutting aspect in the area of problem identification and resolution, associated with the corrective action program component, because the licensee failed to communicate issues identified from self assessments to affected personnel. Specifically, the licensee failed to take corrective action from self assessments that identified the licensee's shortcomings in reviewing vendor prepared design documents. |
| Site: | Columbia  |
|---|---|
| Report | IR 05000397/2011004 Section 4OA3 |
| Date counted | Sep 30, 2011 (2011Q3) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | L Ricketson P Elkmann R Cohen G George L Carson W Walker A Fairbanks J Groom M Hayes E Ruesch D Reinert N Greene |
| CCA | P.6, Self-Assessment |
| INPO aspect | CL.2 |
| ' | |
Finding - Columbia - IR 05000397/2011004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Columbia) @ 2011Q3
Self-Identified List (Columbia)
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