C⁴P-train neutronics tool for supporting safety studies of innovative fast reactors

For studies of innovative nuclear reactors, an advanced safety code, SIMMER, is used at KIT and other institutions. SIMMER generates macroscopic cross-sections for coupled neutronics and thermal-hydraulics transient simulations from a multigroup cross-section library with f-factors. For fuel behavior models coupled to SIMMER, also inventories of He and gaseous fission products are needed. CP-TRAIN is a neutronics tool for generation of SIMMER cross-section libraries and their benchmarking, for computation of isotopic inventories and decay heat. CPTRAIN consists of CP and TRAIN. CP includes general-purpose fine-group cross-section libraries in the CCCC format and tools for generation of coarse-group libraries for SIMMER from fine-group ones. CP also includes a capability for producing multigroup cross-sections with ffactors for isotope mixtures from data for the isotopes. TRAIN can employ CP data for generation of macroscopic cross-sections; then these cross-sections can be used by an ―external‖ neutron transport code for computing cell/reactor neutron fluxes, which can be used then by TRAIN for fuel burn-up simulations. Recently TRAIN was extended and used for burn-up simulations in a molten salt fast reactor as described in the paper. The computed decay heat values agree well with those obtained in the past with Monte-Carlo codes.