The Consortium for Advanced Simulation of Light Water Reactors is a U. S. Department of Energy Innovation Hub charged with developing a virtual reactor toolkit that will incorporate science-based models, state-of-the-art numerical methods, modern computational science and engineering practices, and uncertainty quantification (UQ) and validation against operating pressurized water reactors. It will couple state-of-the-art fuel performance, neutronics, thermal-hydraulics (T-H), and structural models with existing tools for systems and safety analysis and will be designed for implementation on both today's leadership-class computers and next-generation advanced architecture platforms.
This presentation will discuss recent explorations of code-to-code coupling algorithms for tightly coupled nuclear reactor neutronics and conjugate heat transfer physics in parallel. Comparisons will include dampened Picard iteration (Block Gauss-Seidel), Anderson Accelerated Picard iteration, and a Preconditioned Jacobian-Free Newton-Krylov approach. The neutronics formulation solves a k-eigenvalue form of the neutron transport equation using a multi-group approximation in energy, simplified spherical harmonics (SPn) in angle, and finite-difference in space. A Galerkin finite element formulation is used to solve the conjugate heat transfer model for energy conservation within a suite of nuclear fuel rods with heat removal through convection models along the outside of the rods. The coupling algorithms and preconditioning strategies implemented will be discussed. Comparisons of robustness and efficiency for the coupling algorithms will be shown. Issues on software integration complexities will be addressed.