A small fast reactor has the potential to be utilized as a power source applicable to diversified social needs and to reduce capital risks. At remote sites where the population is small and plants cannot be economically connected to a power grid, power sources without refueling whose capacities are <50 MW(electric) are required because the fuel transfer cost is expensive at such sites. In the present study, a small lead-bismuth-cooled core with a 30-yr lifetime has been developed, and a simple plant system without refueling has been sketched. The dimensions of the major components are determined to evaluate its economic potential. Transient analyses of anticipated-transient-without-scram events show that the design has passive safety features suitable for a remote power source.