05000456/FIN-2009003-05
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Finding | |
|---|---|
| Title | Failure to Properly Evaluate Installation of ECCS Throttle Valves |
| Description | A NCV of 10 CFR 50, Appendix B, Criterion III, Design Control, was identified by the inspectors for failure to install a modified Emergency Core Cooling System (ECCS) throttle valve design commensurate with the design control measures applicable to the original design. This resulted in the failure to select a material suitable to the application. Specifically, the licensee selected a design that included gas nitrided surfaces, contrary to the Westinghouse design specification for the original emergency core cooling system throttle valves that prohibited the use of nitrided surfaces in reactor coolant applications. Corrective actions included replacing the ECCS throttling valve that showed worst flow degradation. Additionally the licensee re-performed the surveillance test and adjusted the throttle valves such that any future degradation of the flow area (caused by corrosion or brazing material loss) will not result in pump run-out. The finding was determined to be more than minor because it was similar to Example 5.a of IMC 0612, Appendix E, Examples of Minor Issues, in that a modification that did not meet design requirements was returned to service prior to discovery. The inspectors determined the issue did not result in the actual loss of a safety function and the issue screened out as having very low safety significance. This finding has a cross-cutting aspect in the area of Problem Identification and Resolution associated with the corrective action program attribute, because the licensee did not thoroughly evaluate all aspects of the modification to the ECCS throttle valves. (P.1(c)) |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2009003 Section 4OA2 |
| Date counted | Jun 30, 2009 (2009Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | A Garmoe B Dickson M Holmberg M Mitchell M Perry M Thorpe Kavanaugh R Jones R Ng R Skokowski T Hartman |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Braidwood - IR 05000456/2009003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2009Q2
Self-Identified List (Braidwood)
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