Design of Ultralong-Cycle Fast Reactor Employing Breed-and-Burn Strategy

A new design of ultralong-cycle fast reactor (UCFR) with power rate of 1000 MW(electric) has been developed based on the strategy of breed and burn. The bottom region of the core with low-enriched uranium plays a role of igniter of the core burning and the upper natural uranium region acts as a blanket for breeding. Fissile materials are bred in the blanket and the active core moves upward at a speed of 5.0 cm/year. Through the core depletion calculation using Monte Carlo code McCARD, it is confirmed that a full-power operation of 60 years without refueling is feasible with respect to nuclear isotopics and criticality. Core performance characteristics have been evaluated in terms of axial/radial power shapes, reactivity feedback coefficients, etc. This design will serve as a base model for further design study of UCFRs using light water reactor spent fuels in the blanket region.