Optimization of the self-sufficient thorium fuel cycle for candu power reactors

Abstract

The results of optimization calculations for CANDU reactors operating in the thorium cycle are presented in this paper. Calculations were performed to validate the feasibility of operating a heavy-water thermal neutron power reactor in a self-sufficient thorium cycle. Two modes of operation were considered in the paper: the mode of preliminary accumulation of 233U in there actor it self and the mode of operation in a self-sufficient cycle. For the mode of accumulation of 233U, it was assumed that enriched uranium or plutonium was used as additional fissile material to provide neutrons for 233U production. In the self-sufficient mode of operation, the mass and isotopic composition of heavy nuclei unloaded from the re actor should provide (after the removal of fission products) the value of the multiplication factor of the cell in the fol-lowing cycle K > 1. Addition ally, the task was to deter mine the geometry and composition of the cell for anaccept able burn up of 233U. The results obtained demonstrate that the realization of a self-sufficient thorium mode for a CANDU reactor is possible with out using new technologies. The main features of the reactor en suring a self-sufficient mode of operation are a good neutron balance and moving of fuel through the active core.