COMSOL-Based Nuclear Reactor Kinetics Studies at the HFIR

D. Chandler[1], J. Freels[2], R. Primm III[3], and G. Maldonado[1]
[1]Department of Nuclear Engineering, University of Tennessee, Knoxville, TN
[2]Research Reactors Division, Oak Ridge National Laboratory, Oak Ridge, TN
[3]Primm Consulting, LLC., Knoxville, TN

The computational ability to accurately predict the dynamic behavior of a nuclear reactor core in response to reactivity-induced perturbations is an important subject in reactor physics. Space-time and point kinetics methodologies were developed for the purpose of studying the transient-induced behavior of the High Flux Isotope Reactor’s (HFIR) compact core. The space-time simulations employed the three-energy-group neutron diffusion equations, and the basic nuclear data required was derived from the NEWT and MCNP neutron transport codes.

The neutron diffusion equations, delayed neutron precursor equations, domain movement expressions, etc. were coded into COMSOL via the coefficient form PDE application mode, the ODE application mode, and algebraic equations. Transients initiated by control cylinder and hydraulic tube rabbit ejections were studied.