Operation of CANDU power reactor in thorium self-sufficient fuel cycle

This paper presents the results of calculations for CANDU reactor operation in thorium fuel cycle. Calculations are performed to estimate the feasibility of operation of heavy-water thermal neutron power reactor in self-sufficient thorium cycle. Parameters of active core and scheme of fuel reloading were considered to be the same as for standard operation in uranium cycle. Two modes of operations are discussed in the paper: mode of preliminary accumulation of U-233 and mode of operation ill self-sufficient cycle. For the mode of accumulation of U-233 it was assumed for calculations that plutonium call be used as additional fissile material to provide neutrons for U-233 production. Plutonium was placed in fuel channels, while Th-232 was located in target channels. Maximum content of U-233 in target channels was estimated to be similar to 13 kg/t of ThO2. This was achieved by irradiation for six years. The start of the reactor operation in the self-sufficient mode requires U-233 content to be not less than 12 kg/t. For the mode of operation in self-sufficient cycle, it was assumed that all channels were loaded with identical fuel assemblies containing ThO2 and certain amount of U-233. It is shown that nonuniform distribution of U-233 in fuel assembly is preferable.