An important issue regarding deterministic transport methods for whole core calculations is that homogenised techniques can introduce errors into results. In addition, with modern computational abilities, direct whole core heterogeneous calculations are becoming increasingly feasible.
Following a previous benchmark in this series in 2003, this 3-D extension case was designed to simulate three core configurations with different levels of axial heterogeneity utilising control rods. A majority of the participants obtained solutions that were more than acceptable for typical nuclear reactor calculations, showing that modern deterministic transport codes and methods can calculate the flux distribution reasonably well without relying upon special homogenisation techniques. The report will be of particular interest to reactor physicists and transport code developers.