Fluid-Structure Interaction Modeling of High-Aspect Ratio Nuclear Fuel Plates Using COMSOL

The High Flux Isotope Reactor at the Oak Ridge National Lab is in the research stage of con- verting its fuel from high-enriched uranium to low- enriched uranium. Due to dierent physical properties of the new fuel and changes to the internal fuel plate design, the current safety basis must be re-evaluated through rigorous computational analyses. One of the areas being explored is the uid-structure interaction phenomenon due to the interaction of thin fuel plates (50 mils thickness) and the cooling uid (water). De- tailed computational uid dynamics and uid-structure interaction simulations have only recently become fea- sible due to improved numerical algorithms and ad- vancements in computing technology. For many rea- sons including the already built-in uid-structure in- teraction module, COMSOL has been chosen for this complex problem. COMSOL's ability to solve multi- physics problems using a fully-coupled and implicit solution algorithm is crucial in obtaining a stable and accurate solution. Our initial ndings show that COM- SOL can accurately model such problems due to its ability to closely couple the uid dynamics and the structural dynamics problems.