Assessment of Numerical Methods for Time-Dependent Transport Calculations of Subcritical Systems

The numerical solution of the time dependent transport equation is considered for subcritical injected systems. The scope of the work is to assess the performance of time-implicit discretization schemes of common use.The numerical discretization error is studied with the Fourier method; the separate effects of the time discretization and of the space and angle discretizations are considered.The computational effort required to simulate paradigmatic transients is evaluated.To reduce the costs a modified diffusion acceleration method is proposed, which provides accurate results with substantially lower computational cost.