Pressurized Water Reactor Loading Pattern Design Using the Simple Tabu Search

A computer program based on the simple tabu search has been developed to search for pressurized water reactor loading patterns (LPs). The tabu search is a heuristic procedure for solving optimization problems. To save computer time, a design target was defined, which is the value of the nuclear enthalpy rise hot-channel factor F_H at each fuel assembly (FA) position for zero xenon concentration and zero exposure condition. When the values of F_H of a trial LP satisfy the design target, this LP may meet the design limit at each exposure checkpoint for all rods-out and D-bank half-inserted conditions, which is the design requirement. The objective function was defined to search for an LP whose F_H is smaller than the design target, i.e., a feasible LP. An initial LP is properly generated by using the heuristic rules. Then the LP is rearranged by exchanging FAs or rotating the FA, which is carried out by employing the simple tabu search. The heuristic rules were incorporated into the tabu search to generate the candidate moves so that the search was efficient. The program was demonstrated by successfully generating LPs for the Maanshan nuclear power plant in Taiwan.