05000454/FIN-2009004-04
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Finding | |
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Title | Use of Friction in Design of FHB Crane to Single Failure Proof |
Description | An URI was identified by the inspectors for the licensees use of friction in their seismic analysis methodology that may not be consistent with the design requirements of ASME NOG-1-2004. Specifically, in the seismic analysis of the FHB trolley and components, the licensee used friction force developed at the trolley wheel/rail interface to reduce the horizontal seismic loads applied to the trolley components. Since Table 4154.3-1 of ASME NOG-1-2004 specifies analytical boundary conditions that would prevent sliding between the trolley and the rails, the licensees use of friction is contrary to the requirements of the ASME NOG-1-2004 Rules for Construction of Overhead and Gantry Cranes. The NRC staff is currently reviewing the appropriateness of the licensees application of friction with respect to the design requirements specified in ASME NOG-1-2004. Seismic evaluations of the new single failure proof crane trolley and its components are included in Calculations 36272-02, 36272-12, 36272-13, and 36272-17. The inspectors identified that for evaluation of trolley components in Calculation 36272-17, instead of using seismic loads based on accelerations obtained from the crane dynamic analysis performed in accordance with ASME NOG-1-2004, the licensee used much smaller loads limited by the frictional force at the rail surface. This resulted in a significant load reduction for qualification of the trolley components, and is contrary to the ASME NOG-1-2004, requirements for the boundary conditions to be used in dynamic analysis model. The use of friction was first identified during review of calculations at Exelons LaSalle County Station and is currently being reviewed by the inspectors and NRR staff. The issue is captured in IR 957014 for LaSalle. The licensee subsequently issued IR 966184 for addressing the impact at Byron. Per IR 966184, the license identified that Calculations 36272-12 and 36272-17 utilized friction and the licensee is in the process of revising these and any other affected calculations to remove the use of friction methodology. All revised calculations issued to resolve this concern need to be reviewed. Note that since the licensee has decided to revise the affected calculation, the NRC review may be performed as part of the URI described in Section 4AO5.1.b(3), Review of FHB Crane Trolley Upgrade Design Document Not Completed. This issue will be a URI pending the inspectors reviews of the licensees resolution of the use of friction in their design of structures and components in the upgrade of the FHB crane to single failure proof (URI 005000454/2009004-04;05000455/2009004-04) |
Site: | Byron ![]() |
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Report | IR 05000454/2009004 Section 4OA5 |
Date counted | Sep 30, 2009 (2009Q3) |
Type: | URI: |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | |
Inspectors (proximate) | R Jickling R Ng C Thompson B Bartlett J Robbins J Cassidy E Duncan M Learnj Pearsonj Bozga R Skokowski M Learn E Love C Tilton G Morell R Ng C Thompson B Bartlett J Robbins J Cassidy M Mitchell J Neurauter D Jones S Bakhsh T Go V Meghani |
INPO aspect | |
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Finding - Byron - IR 05000454/2009004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Byron) @ 2009Q3
Self-Identified List (Byron)
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