Benchmark on deterministic 2-D MOX fuel assembly transport calculations without spatial homogenization

An important issue of deterministic transport methods for whole core calculations concerns the accuracy of homogenization techniques. A direct calculation for whole core heterogeneous geometries was not feasible in the past due to the limited capability of computers. With modern computational abilities, direct whole core heterogeneous calculations are becoming feasible. This paper explores a recent OECD/NEA benchmark problem proposed to test the accuracy of modern deterministic transport methods when applied to reactor core problems without spatial homogenization. For this work a two-dimensional configuration was investigated and an accurate Monte Carlo reference solution was obtained. Twenty participants submitted solutions for the two-dimensional configuration and all of the participant solutions were compared to a reference Monte Carlo solution. Overall all the results submitted by the participants agreed well with the reference solution. A majority of the participants obtained solutions that were more than acceptable for typical reactor calculations and the remaining errors in the participant solutions can be attributed to the high order space-angle approximation necessary to solve this particular benchmark problem. It is important to note that the high order space-angle approximation needed for this benchmark is not necessary typical for all such wholecore heterogeneous problems.