ENDF81SaB: ACE Nuclear Data Library based on ENDF/B-VIII.1 Thermal Neutron Scattering Sublibrary

Released: 2025-09-11

On August 30, 2024, the National Nuclear Data Center (NNDC) released the ENDF/B-VIII.1 nuclear data library. The thermal neutron scattering sublibrary contained a total of 114 evaluations for 69 materials. Nine materials (light water, beryllium oxide, beryllium-metal, yttrium hydride, silicon carbide, silicon dioxide, Lucite, liquid hydrogen, and liquid deuterium) were reevaluated, and 18 new materials were added (calcium hydride, uranium hydride, lithium-7 hydride, lithium-7 deuteride, paraffinic oil, polystyrene, teflon, FLiBe, hydrogen fluoride, sapphire, uranium metal, plutonium dioxide, magnesium oxide, beryllium fluoride, magnesium fluoride, beryllium carbide, uranium carbide, and zirconium carbide). Two materials were evaluated with added physics (graphite and beryllium metal with Sd effects). Four material evaluation sets were expanded to include new phases, material conditions, or enrichments (zirconium hydride, 20% porous graphite, uranium dioxide, and uranium nitride). The remaining evaluations were imported from the ENDF/BVIII.0 thermal neutron scattering sublibrary. The files provided in the thermal neutron scattering sublibrary were processed into ACE-formatted files, verified, and validated, resulting in the ENDF81SaB nuclear data library. Material identifiers for use in the MCNP MTn card are given in LA-UR-25-29086.

Documentation

W. Haeck, N. Gibson, N. Kleedtke, "Release of ENDF81SaB: ENDF/B-VIII.1-Based ACE Data Files for Thermal Scattering," Los Alamos National Laboratory Memorandum XCP-5:25-023 (2025). LA-UR-25-29086