Abstract
Recent work in MPACT, the primary deterministic neutron transport solver in CASL’s VERA, has focused on significantly improving the overall performance of the calculations and many components within the code have been improved. The paper focuses on the most recent development to improve the 2D/1D subplane method in preparation for a production-level capability. The key developments presented here focus on incorporating a multilevel-in-space CMFD solver that also collapses on the subplane bases, a dynamic subplane meshing capability that better preserves accuracy during control rod movements, and overall usability improvements to make using the subplane method seamless. Compared to the current default 2D/1D solver in MPACT, substantial improvements are demonstrated on two progression problems, including a standard quarter core model, where potential savings observed at ~2× in memory and ~5-6× in core-hour requirements.
