An Analysis of Transport Effects in Steady-State Simulation of the Molten Salt Reactor Experiment

We use the deterministic neutron transport code QuasiMolto to simulate steady-state operation of the Molten Salt Reactor Experiment (MSRE). Comparisons are made to similar results from the MOST benchmark, the MOOSE-based code Moltres, and the design calculations for the MSRE. In the course of these comparisons, we calculate a value of 0.1799 for the graphite-to-fuel power density ratio, which differs significantly from that seen in other works. We also find uniform graphite heating inadequate to reproduce the characteristic graphite temperature distribution of the MSRE. Leveraging the multilevel projective methodology of QuasiMolto, the influence of transport effects on the modeled problem is found to produce average and maximum group flux variations of 2% to 5% and 30%, respectively, with a 12% variation in the reactivity loss due to delayed neutron precursor drift.