HEAT DIFFUSION IN A CANLESS FAST BREEDER REACTOR CORE

Omission of subassembly cans in fast breeder reactors significantly improves the neutron economy and thus offers interesting economic perspectives. The function of the subassembly cans as guide tubes for the coolant, i. e., for adjusting the local coolant flow to the radial power distribution, can be substituted by double deflection of the coolant flow within the core by blanket assembly rod spacers with low or zero permeability. The paper briefly describes the open core concept and deals in its second part with the role of heat diffusion within the core as one aspect of the thermo-hydraulic layout.