A Stylized Three-Dimensional Pressurized Water Reactor Benchmark Problem with UO₂ and MOX Fuel

This paper fully describes a whole-core benchmark problem based on a small two-loop pressurized water reactor composed of UO₂ and MOX fuel assemblies. The specification includes heterogeneity at both the assembly and the core levels. The geometry and material compositions are fully described, and multigroup material cross-section libraries are provided in the two-group, four-group, and eight-group formats. Detailed Monte Carlo reference solutions including core eigenvalue, assembly-averaged fission distribution, and selected fuel pin fission density distributions are presented for benchmarking diffusion and transport methods. Three different core configurations are presented in this paper, namely, all-rods-out, all-rods-in, and some-rods-in.