Verification of the multi-group diffusion code AZNHEX using the OECD/NEA UAM Sodium Fast Reactor Benchmark

The differences in keff of AZNHEX versus the well validated deterministic codes DYN3D and PARCS are 70 pcm and 113 pcm respectively when using the same set of XS previously generated with the stochastic code SERPENT. Also, the radial power distribution compared between the deterministic codes over the main diagonal of the core presented very good agreement among them. In other exercises, differences in the order of 200 pcm, in the worst cases, were found when comparing integral parameters with SERPENT. The AZNHEX results give the confidence to keep developing the code in order to convert it into the standard domestic tool for hexagonal-z geometry core analysis. Future developments on the code will be focused on the implementation of discontinuity factors and the thermal expansion effects in an operating core as well as the time dependent implementation.