Scalable Parallel Solution Coupling for Multi-Physics Reactor Simulation

Reactor simulation depends on the coupled solution of various physics types, including neutronics, thermal/hydraulics, and structural mechanics. This paper describes the formulation and implementation of a parallel solution coupling capability being developed for reactor simulation. The coupling process consists of mesh and coupler initialization, point location, field interpolation, and field normalization. This capability is tested on two example problems; one of them is a reflector assembly from the ABTR. Performance of this coupler in parallel is reasonable for the problem size chosen and the chosen range of processor counts. The runtime is dominated by startup costs, which amortize over the entire coupled simulation. Future efforts will include adding more sophisticated interpolation and normalization methods, to accommodate different numerical solvers used in various physics modules and to obtain better conservation properties for certain field types.