A neutronic feasibility study on the use of the Pb-Bi coolant in the KALIMER core

A neutronic feasibility study based on the breakeven KALIMER core has been performed for the replacement of sodium coolant with Pb-Bi coolant. Larger pumping power and coolant-to-fuel ratio are needed because of its heavy weight, small conductivity and specific heat owing to the harder neutron spectrum. However, Pb-Bi coolant have good characteristics in aspects of breeding ratio, burnup reactivity swing and coolant void reactivity in comparison with those of Na coolant. In this study, we analyzed the neutronic characteristics of the Pb-Bi cooled breakeven KALIMER core by changing the core height (100cm, 110cm, 120cm) and the lattice pitch to-diameter ratio. The results shows that the reactor cores have the breeding ratio of 1.0∼1.13 and negative coolant void reactivity for 100% voiding in the deriver fuel and satisfy the design limits