Basic study of concentrically zoned fast reactor using natural uranium highly efficiently without fuel reprocessing

Basic nuclear characteristics of the fast reactor is investigated to confirm the feasibility for a practical power reactor utilizing the natural uranium highly efficiently without reprocessing. In this reactor, natural uranium fuels are charged in the outermost zone of core. The fuels are gradually moved to the inner zone with progress of burn up, and the high burnup fuels gathered in the central zone of core are discharged. The burnup of the spent fuel is reached about 350GWd/tHM