COMSOL Simulations for Steady State Thermal Hydraulics Analyses of ORNL’s High Flux Isotope Reactor

P.K. Jain[1], V.B. Khane[2], J.D. Freels[1]
[1]Oak Ridge National Laboratory, Oak Ridge, TN, USA
[2]Missouri University of Science and Technology, Rolla, MO, USA

Simulation models for steady state thermal hydraulics analyses of ORNL’s HFIR have been developed using COMSOL. A single fuel plate and coolant channel of each type of HFIR fuel element was modeled in three dimensions. The standard k-? turbulence model was used in simulating turbulent flow with conjugate heat transfer. The COMSOL models were developed to be fully parameterized to allow assessing impacts of fuel fabrication tolerances and uncertainties related to LEU fuel design. Heat source input for the simulations was obtained from separate MCNP calculations for the axially non-contoured LEU fuel designs at the beginning of the reactor cycle. Mesh refinement studies have been performed to calibrate the models against the pressure drop measured across the HFIR core.