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

摘要

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 ~(233)U and mode of operation in self-sufficient cycle. For the mode of accumulation of ~(233)U it was assumed for calculations that plutonium can be used as additional fissile material to provide neutrons for ~(233)U production. Plutonium was placed in fuel channels, while ~(232)Th was located in target channels. Maximum content of ~(233)U in target channels was estimated to be ～13 kg/t of ThO_2. This was achieved by irradiation for six years. The start of the reactor operation in the self-sufficient mode requires ~(233)U 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 ThO_2 and certain amount of ~(233)U. It is shown that nonuniform distribution of ~(233)U in fuel assembly is preferable.