Deterministic solutions for 3D Kobayashi benchmarks

We present results for the set of three-dimensional radiation transport ben chmark problems with void region proposed by Kobayashi. Reference solutions for the pure absorber cases were obtained by direct quadrature. All cases were calculated by the three-dimensional discrete ordinates nodal and chara cteristics code IDT. The discrete ordinates results for the pure-absorber c ase suffer strongly from ray effects which remain present also in the 50%-s cattering cases. We show that these benchmarks are a hard problem for a dis crete ordinates production code which uses direct computation, i.e., withou t using a first collision source to remedy the ray effect, and that such te chnique must be applied to get accurate results. (C) 2001 Elsevier Science Ltd. All rights reserved.