Error Control in a Time-Dependent Slice-Balance Method, invited

摘要

The primary purpose of the current research is to expand the capabilities of an existing steady state radiation transport solver to include time-dependent computations. The particular solver that will be utilized is NEWTRNX [1], which is a 3D implementation of the slice balance approach (SBA), or Extended Step Characteristics [2], being developed at Oak Ridge National Laboratory (ORNL). One of the most appealing aspects of SBA is its small memory requirement due to the fact that only the angular moments of the flux on a coarse-mesh need to be stored rather than the entire flux for all discrete ordinate directions on a fine angle-dependent spatial mesh. A primary motivation for a time-dependent implementation, therefore, is to preserve this storage economy. However, due to the standard finite-difference formulation of the time derivative in the transport equation, more spherical harmonic moments may have to be retained than would be necessary in a comparable steady-state calculation.