An Updated Simplified FE Model Generation Technique for Fuel Assembly Seismic/LOCA Analysis

摘要

This study contains an updated finite element model generation technique for the simplified fuel assembly model, which is used for Seismic/LOCA analysis of the reactor internals. The simplified fuel assembly model consists of simple beam and rotational springs at each end of the fuel assembly. To determine two non-dimensional constants (αL and αU), which are the function of spring constants, beam rigidity, and fuel assembly length; an optimal design technique was used. A commercial finite element analysis program, ANSYS, was used to find beam rigidity and to simulate various kinds of tests. The simplified finite element model was verified by comparing with various full-scale test results, which are static stiffness test, free/forced vibration test, and dynamic impact tests. All the simulations with the simplified model showed a good agreement with the full-scale test results. It is found that ANSYS, the GUI based commercial finite element analysis program, generates more efficient and reliable results than the traditional text based analysis program. ANSYS also visualized static and dynamic responses of fuel assembly under various loading conditions, which may be utilized to improve the current seismic/LOCA related fuel assembly design margin.