A study of the required fidelity for the representation of angular distributions of elastic scattering in the resolved resonance region for nuclear criticality safety applications

Angular distributions of elastic scattering in the resolved resonance region can be reconstructed from the resonance parameters directly, or they can be provided in a point-wise manner with respect to incident neutron energy in nuclear data files. This study investigates the required fidelity in energy for the accurate representation of the angular distributions of elastic scattering in the resolved resonance region with respect to the performance in neutron transport calculations for nuclear criticality safety applications. A dense energy grid such as that used to represent angle integrated cross sections in the resolved resonance region, is not necessary for representation of angular distributions. A reduction in the number of points in energy on the order 5-10x (a 5-10x reduction of storage) gives the same results in a wide variety of neutron transport problems simulated. (authors)