[2B13-17] Analysis Method 2

[2B15] Impact of Flat Flux Approximation on Convergence Performance of ACMFD Acceleration

*Yoshiki Oshima¹, Tomohiro Endo¹, Akio Yamamoto¹ (1. Nagoya Univ.)

Keywords:ACMFD acceleration, Flat flux approximation, Linearized Fourier analysis, Convergence, MOC

The net neutron current formula of the ACMFD acceleration method is obtained by the analytical solution for the 1D diffusion equation. The analytical solution can be derived with/without the flat flux approximation to the self-scattering source, while this approximation is typically applied to the transport calculation. From the viewpoint of consistency of the acceleration and transport calculations, consideration of the equivalent numerical approximations may be important for better convergence of acceleration. In this study, numerical calculations and the Linearized Fourier analysis on the 1D slab geometry clarify the relation between the flat flux approximation and convergence in the ACMFD acceleration method.