Solution of the improved and generalized quasistatic methods using an analytic calculation or a semi-implicit scheme to compute the precursor equations

The precursors in the point kinetics equations for both improved and generalized quasistatic methods are solved using two different methods; an analytic method where the precursors are integrated over the time and a solution given by a semi-implicit scheme. The results obtained by implementing the semi-implicit method in the TRIVAC-3 reactor code are very close to those obtained by analytic calculation performed by the Kaps and Rentrop algorithm for small step size and the total calculation time is reduced by approximately one-half.