Nuclear fuel management

This chapter discusses the resolution of the pressurized water reactor (PWR) reload core optimization problem. A typical PWR core contains, depending on its rated thermal power, anywhere from 121 to 241 fuel assemblies arranged with quarter core (reflective or rotational) symmetry. Nuclear power reactors inherently have some highly nonlinear characteristics, which means that whatever objective function and constraints are used to define and quantify acceptable LPs, some of these system variables will inevitably be nonlinear functions of the problem's control (decision) variables. A key component in the optimization process itself is the generation of new solutions. For a PWR reload core problem, the control (decision) variables to be determined include the fuel assembly to be loaded in each location, the BP loading with each assembly, and the orientation of each assembly. Simulated annealing as implemented in the code FORMOSA-P enables in-core PWR fuel management problems to be solved within a reasonable computational time frame, offering the designer, through the archiving schemes, a selection of near-optimum solutions from which to choose and considerable insight into the individual characteristics of each problem.