Investigation of PWR core optimization using harmony search algorithms

This work addresses applications of the classical harmony search (HS), improved harmony search (IHS) and the harmony search with differential mutation based pith adjustment (HSDM) to PWR core reloading pattern optimization problems. Proper loading pattern of fuel assemblies (FAs) depends on both neutronic and thermal–hydraulic aspects; obtaining optimal arrangement of fuel assemblies, FA, in a core to meet special objective functions is a complex problem. In this paper, in the first step HS, IHS and HSDM methods are implemented and compared with other meta-heuristic algorithms on Shekel’s Foxholes problem. In the second step to evaluate proposed techniques in PWR cores, maximization of multiplication factor, keff, decreasing of power picking factor (PPF) as much as possible and power density flattening are chosen as neutronic objective functions for two PWR test cases although other variables can be taken into account. In the third step, obtaining maximum core average critical heat flux (CHF) along no void generation throughout the cores are two thermal–hydraulic objective functions which are included to the desired neutronic objective functions. For neutronic and thermal–hydraulic computation, PARCS (Purdue Advanced Reactor Core Simulator) and COBRA-EN codes are used respectively. Coupling the harmony search with the PARCS code and the COBRA-EN code, we developed a core reloading pattern optimization code. The results, convergence rate and reliability of the techniques are quiet promising and show that the harmony algorithms perform very well. Furthermore, it is found that harmony searches have potential for other optimization applications in other nuclear engineering field. 2013 Elsevier Ltd. All rights reserved.