In this contribution, we present a new package for creating fixed-source neutron source profiles for OpenMC from both simulated and experimental tokamak plasma states. Realistic fusion neutronics simulations ultimately require information on plasma equilibrium, plasma transport, and a realistic source geometry. In this work, a new flexible tool is presented that allows the user to input detailed plasma states to create OpenMC neutron sources for fixed-source problems. The toolkit accepts radially and poloidally varying plasma density and temperature profiles from either experimental or simulated plasma states. Either D-T or D-D reaction rates may be used in the case of predictive or experimental simulations, respectively. This process provides a realistic neutron source that is intrinsically coupled to tokamak plasma physics parameters.

We demonstrate the framework using a source modeled after an experimental neutron profile from the Mega Ampere Spherical Tokamak–Upgrade (MAST-U). An additional feature of this coupling is the ability to self-consistently convert the Monte Carlo tallies using total volumetric neutron production instead of relying on a measured total neutron production rate typical of these simulations. Experimentally informed and flexible source definitions for neutronics modeling are crucial to streamlining the design process of any future fusion pilot plant studies.