Efficient Parallel Solution of the 3D Stationary Boltzmann Transport Equation for Diffusive Problems

TL;DR

This paper introduces a highly efficient parallel method for solving large-scale 3D stationary Boltzmann transport equations in diffusive problems, significantly reducing computation time for complex nuclear simulations.

Contribution

The paper presents a novel combination of nested parallelization and PDSA acceleration applied to 3D transport problems, enabling rapid solutions of extremely large neutronic models.

Findings

Solved problems with up to 10^12 degrees of freedom in under an hour

Demonstrated efficiency of combined parallelization and PDSA techniques

Achieved significant speedup over traditional methods

Abstract

This paper presents an efficient parallel method for the deterministic solution of the 3D stationary Boltzmann transport equation applied to diffusive problems such as nuclear core criticality computations. Based on standard MultiGroup-Sn-DD discretization schemes, our approach combines a highly efficient nested parallelization strategy with the Piecewise Diffusion Synthetic Acceleration (PDSA) parallel technique applied for the first time to 3D transport problems. These two key ingredients enable us to solve extremely large neutronic problems involving up to $10^{12}$ degrees of freedom in less than an hour using 64 super-computer nodes.