Dynamics of nuclear reactor cores based on one- and two-dimensional multigroup diffusion theory

In this work, results obtained with a program that solves the neutron kinetics equations on the multigroup diffusion theory, are presented together with the thermal-hydraulic equations, for considering the feedback effects. The equations are solve numerically, at the neutron kinetics, at the space and time, on the cylindrical or cartesian geometries, one or two dimensional, with any delayed neutron groups. The program incorporates a module that solve, by finite difference in the fuel, the temperatures in a rod or plate, representative of one spatial-mesh. With these temperatures, during the transient, it is actualized the multigroup constant strongly dependent of the temperature. One case in calculate and the results exhibited show that the strategy adopted is adequate for analyzing transients where local changes compromise the point kinetics model. (author). 4 refs, 11 figs, 5 tabs