Abstract: A method for determining a fresh fuel bundle design for a core of a nuclear reactor may include defining a plurality of inputs including user-defined target conditions for evaluating one or more reference fresh fuel bundle designs for each of N bundle groups, and generating a response surface based on making single rod-type changes in each (i,j) rod location of each bundle of a given reference bundle design being evaluated for each of the N bundle groups. A search algorithm may be iterated to evaluate a given combination of multiple rod-type changes made simultaneously across each of the N bundle groups using the generated response surface to determine an accepted fuel bundle design for each of the N bundle groups that satisfies the user-defined target conditions.

Abstract: In the method, a reference core design is generated based on a defined set of limits. The set of limits may include a target hot excess reactivity constraint to be satisfied over a given core energy cycle and a given desired control blade definition that is set for the cycle. A reference core design is generated based on the defined limits. A unique subset of fresh fuel bundles is subject to an iterative improvement process including replacing, at each fuel location, at least one of the current fresh fuel bundles with at least one of the selected fresh fuel bundles, and simulating reactor operation on the reference core design to obtain a plurality of outputs to be ranked based on the defined set of limits. The highest ranked output may represent an accepted core design with set control blade definition that satisfies the target hot excess reactivity constraint.

Abstract: According to the method, a reactor core is shut down during the operation cycle. One or more fuel bundles of the reactor core are then moved to new positions within the reactor core to increase a total energy, output of the reactor core as compared to continuing operation of the reactor core without the shutting down and moving steps.

Abstract: A method, arrangement and computer program is described for generating 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. A given candidate fresh fuel bundle may be modified by making at least one rod-type change from the set therein. A core loaded with the modified bundle design may be simulated to generate bundle performance outputs. The bundle performance outputs may be ranked based on a plurality of user-input limits. The modified candidate fresh fuel bundle design may be stored, if the bundle performance outputs meet, or are within an accepted margin to, the user-input limits, so as to generate the database.

Abstract: A method, arrangement and computer program is described for determining a set of standardized rod types for use in a nuclear reactor core. The method may include defining a set of rod type-related limits, and determining, based on the limits, an initial population of rod types to be evaluated for use in cores of a selected number of nuclear reactor plants. Based on the initial population of rod types a database of selectable fresh fuel bundle designs applicable to the one or more cores may be generated. Bundle data related to at least a subset of the selectable fresh fuel bundle designs may be retrieved from the database, and a target number of rod types may be selected from the initial population based on the retrieved bundle data as the set of standardized rod types.