Nuclear Reaction Theory for Stockpile Stewardship and Non-proliferation

The process of creating a nuclear data evaluation combines differential experimental data with theoretical model calculations to provide a community recommended value, with uncertainties, to be used in integrated physics codes. Depending on the observable of interest, the reaction under consideration, and the required energy range, a variety of reaction theories are used to create this data. Cross sections for nucleons incident on light nuclei are calculated using R-maxtrix theory, and those for medium-mass and heavy-mass targets above the resonance range are calculated from Hauser Feshbach statistical theory. Fission observables, beyond the cross section, present their own challenges and require specialized – and often phenomenological – models to produce observables of interest, such as neutron and γ-ray multiplicities and energy spectra. In this talk, we will outline these different reaction theories and discuss how information from basic science makes its way through the evaluation process into applications.