Method, arrangement and computer program for generating database of fuel bundle designs for nuclear reactors

A method, arrangement and computer program is described for generating (S310) a database of selectable fresh fuel bundle designs usable in one or more nuclear reactors. In an example, an initial population of candidate fresh fuel bundle designs may be generated and a set of rod-type changes to make to a given candidate in the initial population may be established (S320). A given candidate fresh fuel bundle may be modified (S330) by making at least one rod-type change from the set therein. A core loaded with the modified bundle design may be simulated (S340) to generate bundle performance outputs. The bundle performance outputs may be ranked (S350) based on a plurality of user-input limits. The modified candidate fresh fuel bundle design may be stored (S360), if the bundle performance outputs meet, or are within an accepted margin to, the user-input limits, so as to generate (S400) the database.