[1F01-04] Analysis method 1

9:50 AM - 10:05 AM JST(12:50 AM - 1:05 AM UTC)

[1F02] Study of Tightly Coupled Methods Using FEM and JFNK for the Time-Dependent Neutron Diffusion Equation with Feedback

*Rikuto Kasama¹ (1. JAEA)

Keywords:

Tight Coupling,Time-Dependent,FEM,JFNK,Diffusion Equation

Tightly coupled calculations of the time-dependent neutron diffusion equation with feedback were performed using the Finite Element Method (FEM) and the Jacobian-Free Newton–Krylov method (JFNK). In multiphysics simulations, loosely coupled approaches, in which each physical model is solved sequentially, are widely used. However, these approaches often suffer from convergence degradation in systems with strong nonlinearities induced by feedback. In this study, tightly coupled methods were implemented by combining FEM and JFNK. The performance of the tightly coupled calculations was compared with that of loosely coupled calculations.