Preliminary neutronics design and analysis of CANDLE reactor core with UMo fuel and lead coolant

Abstract The CANDLE reactor, as a kind of travelling wave reactor, in which the shapes of neutron flux and power distribution remain constant at equilibrium state, which moves along the axial direction, has innovative burnup characteristics. In this paper, a CANDLE reactor with UMo alloy as fuel and lead as coolant is proposed. Neutronics calculations and performance analysis of the reactor are carried out using RMC with ENDF/B-VII database, including Mo content in the fuel, 208 Pb content in the lead coolant, ignition zone length and ignition zone fuel enrichment. The results show that the CANDLE reactor with 10.5 % enrichment U8Mo alloy as the fuel, 100 % 208 Pb as the coolant and an ignition zone length of 75 cm exhibits optimal neutronics properties. After about 20 years, the power distribution tends to be stable and moves along the axis in a fixed distribution with a rate of about 3.0 cm/year, with a sufficient critical safety margin and stable breeding performance. This provides a feasible technical path for efficient utilization of uranium resources.