Development of a Three-Dimensional Simulator of a DIDO-Type Reactor

Abstract

A three-dimensional neutronic simulator of the Danish research reactor DR3 has been developed. The demands of a more effective utilization of the reactor and its facilities have required a more detailed calculational tool than has been applied so far. Thus, the capabilities of the simulator should be to calculate reactivity changes, burnup distributions and flux distributions in three dimensions on an off-line, nonreal time computer. A great deal of attention has been devoted to the treatment of the coarse control arms. The model has been tested against measurements with satisfying results. Furthermore, the model has been used to analyse a proposal for a new core design called ring-core, where four central fuel elements are replaced by four dummy ones with heavy water to increase the thermal flux in the center of the reactor.