A Parallel Multi-Domain Solution Methodology Applied to Nonlinear Thermal Transport Problems in Nuclear Fuel Pins

TL;DR

This paper presents a parallel solution methodology for nonlinear thermal transport in nuclear fuel rods, leveraging physics-based preconditioning and demonstrating scalability and independence from subdomain count.

Contribution

The authors develop a physics-informed preconditioning approach within a Jacobian-Free Newton Krylov framework for coupled nonlinear thermal problems in nuclear fuel applications.

Findings

Achieved efficient parallel performance with weak and strong scaling.

Preconditioner effectiveness is independent of the number of fuel subdomains.

Successfully coupled thermal transport with surface physics and external radiation transport.

Abstract

This paper describes an efficient and nonlinearly consistent parallel solution methodology for solving coupled nonlinear thermal transport problems that occur in nuclear reactor applications over hundreds of individual 3D physical subdomains. Efficiency is obtained by leveraging knowledge of the physical domains, the physics on individual domains, and the couplings between them for preconditioning within a Jacobian Free Newton Krylov method. Details of the computational infrastructure that enabled this work, namely the open source Advanced Multi-Physics (AMP) package developed by the authors is described. Details of verification and validation experiments, and parallel performance analysis in weak and strong scaling studies demonstrating the achieved efficiency of the algorithm are presented. Furthermore, numerical experiments demonstrate that the preconditioner developed is independent of the number of fuel subdomains in a fuel rod, which is particularly important when simulating different types of fuel rods. Finally, we demonstrate the power of the coupling methodology by considering problems with couplings between surface and volume physics and coupling of nonlinear thermal transport in fuel rods to an external radiation transport code.