Estabilization Time for Subcritical System with Different External Neutron Source

This work aims at studying one dimensional spatial kinetics equations for ADS (Accelerator Driven System) type reactors, through computational simulations. Where the neutrons diffusion equations are discretized espatially by the finite differences cell centered mesh scheme and time discretized using the Crank-Nicolson method. Discretized equations used with fixed source problem are programmed in FORTRAN and used to simulate the system behavior, with different neutron source types. In this way, we can analyse the instant of time when the subcritical system becomes stationary, or the time interval corresponding to the stationary flux, for different external sources. The result shows that, it is always possible to reach system stability where no oscillation is detected, even for pulsed sources