COMPARISON BETWEEN EQUILIBRIUM CYCLE AND SUCCESSIVE MULTICYCLE OPTIMIZATION METHODS FOR IN-CORE FUEL MANAGEMENT OF PRESSURIZED WATER REACTORS

摘要

Analyses of an equilibrium cycle are useful for evaluating newly designed fuels, defining an envelope of core operating parameters, and so on. However; generation of a loading pattern for the equilibrium cycle is much more difficult than that of a single cycle. Therefore, a loading pattern optimization code for the equilibrium cycle of pressurized water reactors, OPAL, has been newly developed on the basis of the simulated annealing method. In order to verify the capability of the OPAL code; comparison with successive multicycle optimizations was performed while fixing the number of fresh fuel in each cycle. Through benchmark calculations, it was found that the result of the equilibrium cycle optimization was almost compatible with that of the successive multicycle optimization, when the definition of each objective function was similar. However successive multicycle optimization includes some ambiguity due to limits on the number of calculated cycles, since it requires much computation time. Consequently, the equilibrium cycle optimization has advantages including the quantitative comparison of the core neutronic performances. [References: 18]