A multilevel projective method and residual balance algorithm for circulating fuel reactor kinetics

A novel multilevel projective method for solving the temperature-dependent neutron kinetics equations of a circulating fuel reactor (CFR) is presented. The method is described in RZ geometry for an arbitrary number of neutron energies and delayed neutron precursor groups, and assumes purely axial flow. A residual balance iterative algorithm intended to mitigate over-solving in multilevel coupling is also presented. Over-solving can occur when a solution at an inner level is allowed to converge to a greater degree than that present at an outer level. A demonstration on a channel-type CFR is presented, as well as a parametric study of the balance parameters in the proposed iterative algorithm. Heavily relaxed values for the balance parameters are shown to decrease solution time of the demonstration problem by 33% when compared to a fixed point iteration approach. (authors)