Simulations of neutron noise in the research reactor AKR-2: comparison between a discrete ordinates and a diffusion-based method

Paper in proceeding, 2022

A diffusion-based and a discrete ordinates method are used to simulate a neutron noise experiment in the research reactor AKR-2 at Technische Universität Dresden, Germany. The AKR-2 reactor provides an interesting case for the comparison between the two methods because it is characterized by large heterogeneities and regions with low macroscopic neutron cross sections. For the calculations, the same spatial discretization and the same set of two-energy macroscopic neutron cross sections with isotropic scattering are used. Significant discrepancies between the diffusion-based and discrete ordinates methods are found in regions of the systems where the diffusion approximation is expected to be inaccurate in reproducing characteristics of the static neutron flux and neutron noise.