The Liquid Metal Breeder (LIMB) reactor is an internally-cooled fluid fuel reactor based upon a Th232-U233 thermal breeder cycle. It employs a molten lead coolant, a uranium-bismuth solution fuel, a thorium bismuthide dispersion in lead-bismuth blanket fluid and a graphite moderator. Heat from the fuel is transferred through a graphite fuel element to the coolant which transports the heat to an external boiler and pump. This arrangement overcomes the major disadvantages found in previous “externally-cooled” liquid-metal-fuel reactors. Equilibrium concentrations of uranium isotopes heavier than U233 and other reasonable assumptions were derived from existing information and then used to develop a broad survey of LIMB reactor sizes. Two sizes, 200 and 1000 MW(th), were chosen for more detailed evaluation. The 200 MW(th) has a potential breeding ratio of 1.08 and an 8 year doubling time. The 1000 MW(th) reactor has a breeding ratio of 1.05 and a 12 year doubling time. Using the most pessimistic estimates on processing could reduce the breeding ratio, while improvements in design and the utilization of low-cross-section coolants can counteract these losses. LIMB reactor technology can lead to an efficient breeder, even in large power sources, and warrants further engineering evaluations.