Paneling Strategy for Ultra-Fine Group Slowing Down Numerical Benchmarks

Generation of multigroup (MG) cross sections lies at the heart of reactor physics methods. A great effort has been made and will continue to be made in the future to develop accurate spectrum codes able to evaluate weighting spectra to produce representative MG cross section libraries for lattice codes. Since the accuracy of these codes is arguably crucial to predicting reactor behavior, there is always a need for verification and improvement. In this paper, we introduce a new solution to the neutron slowing down equation in terms of multi-energy panels, in order to establish a computational benchmark featuring an ultra-fine group (UFG) calculation where the number of groups could be on the order of 105 [1]. In addition, since nuclear data play a central role in the development of an UFG capability to verify spectrum codes independently, one of our main tasks is to connect, in a straightforward manner, to the ENDF nuclear data files at Brookhaven National Laboratory (BNL). In this way, we intend to pave the way for wide use of paneling strategies for UFG calculations.