COMPUTER IMPLEMENTED METHOD FOR MODELIZING A NUCLEAR REACTOR CORE AND A CORRESPONDING COMPUTER PROGRAM PRODUCT

The method comprises the steps of: partitioning the core in cubes to constitute nodes of a grid for computer implemented calculation, splitting the cubes into a first category and a second category, each cube of the first category being adjacent only to cubes from the second category so that the first category and second category of cubes constitute a checkerboard-like pattern, ordering the cubes of the first category and then the cubes of the second category, calculating neutron flux and/or thermohydraulics parameters by using an iterative solving procedure of at least one linear system and/or an eigensystem, the components of an iterant of the linear system and/or the eigensystem constituting the neutron flux and/or thermohydraulics parameters to be calculated, wherein, during the iterative solving procedure, calculations are conducted on the cubes of the first category then on the cubes of the second category.