05000483/FIN-2008003-07
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Finding | |
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| Title | Licensee-Identified Violation |
| Description | 10 CFR Part 50, Appendix B, Criterion III, requires measures be established to assure that applicable regulatory requirements and design basis be correctly translated into specifications, drawings, procedures, and instructions. Technical Specifications 3.5.2 and 3.6.6 require that residual heat removal and containment spray system components remain operable. Contrary to this, measures were not adequate to assure installed center tube diameters for the containment recirculation sump modification were correctly accounted for by an accurate net positive suction head calculation. The vendor supplying AmerenUE the containment recirculation sump strainer identified that associated Vendor Calculation TDI-6002-05 for clean strainer head loss did not account for the installed orifices located in the strainer support plate. The size of the orifice beneath each strainer was smaller than assumed in head loss calculations and was not large enough to prevent head loss in excess of the net positive suction head required as defined in the purchase specification supplied to the strainer vendor. The additional head loss due to the calculation translation error was 2.28 feet. This resulted in required net positive suction head being less than available. AmerenUE performed three separate operability determination reviews to demonstrate that the head loss margin could be recovered. The initial operability determination on January 22, 2008, addressed the smaller support plate orifice holes by using a separate vendor\'s flow analysis of the residual heat removal and containment spray piping systems to demonstrate lower flow and head losses than described in the FSAR. This operability determination resulted in the limiting case flow path being the hot leg recirculation flow path. Another operability review on March 12, 2008, addressed a nonconservative temperature correction through the orifices. Subsequent to this, the licensee informed the NRC that the additional nonconservative inputs were used in the January 22, 2008, flow re-analysis of the residual heat removal system. Additional analyses were performed to regain margin. This resulted in the limiting case flow path changing from hot leg recirculation to cold leg recirculation. This example of inadequate design control was captured in the licensees corrective action program as CARs 200800461 and 200802618. These corrective action reviews documented three causes related to the following design error: FnTime pressure to address Generic Letter 2004-02 FnA complex design with parallel sequencing of different parts of the Design FnAmerenUE not independently verifying the vendor\'s design due to perceived expertise and an approved 10 CFR Part 50, Appendix B, Quality Assurance program. AmerenUE did not perform a review of the design, nor did they contract to have a third party engineering review of the design. This finding is greater than minor because it is similar to the Example 3j in Manual Chapter 0612, Appendix E, Examples of Minor Issues, in that the contractor error translating the design to the calculations resulted in a condition where there was reasonable doubt on the operability of the ECCS. This finding is of very low safety significance because it was a design or qualification deficiency confirmed not to result in loss of operability. This licensee-identified violation closes out Unresolved Item 05000483/2008002-01 |
| Site: | Callaway  |
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| Report | IR 05000483/2008003 Section 4OA7 |
| Date counted | Jun 30, 2008 (2008Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | G Guerra D Dumbacher V Gaddy J Groom |
| INPO aspect | |
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Finding - Callaway - IR 05000483/2008003 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Callaway) @ 2008Q2
Self-Identified List (Callaway)
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