ORNL teams are dedicated to supporting the latest technology advancements, including very large, complex interim storage sites for used fuel; analysis of advanced reactors including molten salt reactors (MSRs), fluoride-salt-cooled high-temperature reactors (FHRs), high-temperature gas-cooled reactors (HTGRs) and sodium-cooled fast reactors (SFRs); analysis of advanced technology fuels (ATFs); and advanced validation approaches for new or challenging systems. A sampling of the enhancements in our production tools to support these technologies is provided here.
A significant activity to support these concepts is the integration and enhancement of the Shift Monte Carlo from CASL for use in SCALE. Shift integration provides criticality, shielding, S/U, and depletion capabilities. Integrated with the TRITON and Polaris sequences, Shift provides reference 3D continuous-energy depletion capabilities. Beyond its application in CASL, Shift is extended to generate nodal cross section data for use in core simulators like PARCS, especially to capture 3D effects important for advanced reactors, including leakage effects and control elements in reflector regions. The Polaris lattice physics sequence of SCALE is enhanced to support ATF concepts, as well as hexagonal geometry for SFRs, and SCALE neutronics capabilities are integrated with Sandia National Laboratories’ MELCORE severe accident tool, as well as the NRC’s new FAST fuel performance code.
For HTGRs and FHRs, the Shift Monte Carlo code includes a new random geometry generator that is especially designed to for tristructural-isotropic (TRISO) fuel and pebble loading.
For liquid-fueled MSRs, SCALE is being enhanced to include a delayed neutron precursor drift and chemical feed capability that can be coupled to other tools. The VERA tool from CASL is being expanded to provide a fully integrated multiphysics capability capable of 3D analysis of MSRs with feedback effects in VERA-MSR.
Many of these advanced systems have unique materials and neutron spectra compared to traditional LWRs, so new AMPX nuclear data libraries are being developed and validated to support these technologies.