A higher order hexagonal-z nodal transport method

Abstract

A higher order one-dimensional transport solution module based on the boundary sources method is implemented in Wagner's (hexagonal-z nodal) code HEXNOD. We first describe and slightly simplify Wagner's nodal technique for reducing the multidimensional transport equation to a set of coupled one-dimensional equations, taking this opportunity to stress that nodal engineering methods of this type make use of a nonltnear (actually affine) approximation to the nodal response. We next summarize the basics of the boundary sources method, whose combined use with Wagner's nodal approach leads to the new HEXBS method.Numerical results reported for a series of benchmark problems show that the new method is more accurate that the original one and that it successfully applies to distorted core configurations. On the other hand, it is somewhat slower than the original method but this may be ascribed to the fact that the present version is far from optimized.