Scheduling fuel-shuffling operations for a nuclear power reactor

Abstract

During the refueling of a pressurized water nuclear reactor, a group of operations termed the fuel shuffle is performed. Certain fuel and control components are removed from or inserted into the reactor core. Specific assemblies are transferred to new, predetermined locations within the core. An analysis of the problem of scheduling these fuel-shuffling operations is presented. The objective is to minimize the shuffle completion time in order to ensure that the fuel shuffle does not delay reactor startup.

A heuristic scheduling procedure currently employed in industry involves the decomposition of the problem into groups of related operations. A computer program is used for the identification of the groups in a given shuffle and for the application of scheduling rules for the individual groups.

To provide improvements over existing techniques, attention is focused on the development of heuristic methods for scheduling these groups of operations. These groups are also combined, and an integer programming model for this integration process is presented. Three sample shuffles are considered, and an analysis of effective scheduling techniques is conducted for a representative set of fuel-handling equipment.

Efforts are made to eliminate the unnecessary equipment moves and idle time present in existing schedules. Improved, near-optimal schedules are developed, and the potential benefits gained from future efforts to reduce the shuffling time are shown to be insignificant.