Multigroup Cross Section Generation with Spatial and Angular Adjoint Weighting

The multigroup discretization is the most common technique used to treat the energy variable in deterministic transport methods. In contrast, most Monte Carlo simulations are able to use the piecewise linear continuous, or pointwise, energy discretization. Monte Carlo simulations may thus be used to benchmark approximations made in multigroup calculations. Several such benchmarks and other studies have been applied to the problem of light water reactor pressure vessel fluence determination and reduction at Pennsylvania State University. These studies indicate that a significant portion of the discrepancy between Monte Carlo and deterministic calculations may be attributed to the techniques used to generate multigroup constants.