Application of the integer programming methods for solving the problems of the fuel assembly recharging optimization

Presented are the results of calculation investigations, carried out for testing applicability of the developed algorithms and computer codes, based on using the methods of integer programming, for solving the problem of optimizing the parameters of fuel assembly (FA) and shim rod (SR) recharging in a nuclear reactor. The optimizing method of fuel assembly and shim rod recharging includes the following procedure. Each physical zone of the reactor has its storage. When recharging the fuel assemblies and shim rods from the storage only assemblies and rods from the corresponding zone can be substituted. The shim rod consists of two parts: active and passive. Physical calculation of the reactor is carried out within the limits of few group diffusion approximation for one-dimensional configuration (plane, cylinder, sphere). The results of solving the considered test optimization tasks permit to conclude, that the developed method is quite effective and reliable enough. The solution of the considered tasks has been obtained at three or four steps of the iterative process. High convergence rate is explained by the fact, that each step of iteration process contains the information on changing (in linear approximation) the functional surfaces of the optimization task within the range of control parameters variations, which makes it possible to determine already at the initial steps the approximate solution of the problem, and the next steps are connected only with refinement of this solution