APPLICATION OF THE METHOD OF MANUFACTURED SOLUTIONS TO VERIFY A NUCLEAR REACTOR PHYSICS COMPUTATIONAL CODE USING THE METHOD OF CHARACTERISTICS

Abstract

The method of characteristics (MoC) has become an accepted tool for lattice physics calculations. MoC has many advantages such as accurate representations of both the lattice geometry and the boundary conditions. The flat source (FS) approximation is most commonly used, and the linear source (LS) approximation can improve the accuracy by preserving higher order spatial moments of the neutron source. However, as a non-standard spatial discretization method, the order of accuracy of the spatial discretization is more difficult to obtain, especially for analyzing linear source approximation, because the MoC method utilizes two sets of spatial meshes – the FS mesh and the set of characteristic rays that integrate the transport equation over the FS mesh. In this work, we analyze the order of accuracy with spatial resolution in MoC in planar geometry for both FS and LS approximations and verify our predictions with the Method of Manufactured Solutions (MMS). It is shown that the flat source approximation is second order accurate and that the linear source approximation has a fourth order accuracy.