Using the PCA method in classical point kinetics and modified point kinetics for transient reactivity step

Abstract

The objective of this work is to use the numerical method known as PCA - “Piecewise Constant Approximation” in the solution of the classical point kinetics equations for six neutron precursor groups. The time-dependent reactivity function is approximated by piecewise constant functions and the resulting first-order ordinary differential equation system is solved exactly over each time step. Numerical simulations with step reactivity functions are made and the solutions are compared with results given in the published literature. The method is later extended to the so called modified neutron point kinetics, which has the time derivative of the neutron current not negligible.