Thermal design of a fusion breeding blanket

A thermal design study of a tritium breeding blanket of a fusion reactor is conducted. A cooling structure with a helium gas gap between the cooling tube and the breeding material (Li2O) is employed in order to keep the temperature of Li2O within the range of 4000C to 12000C. We determined, in detail, an optimum helium gap width and optimum cooling tube pitches in the Li2O region taking into account the estimation error of nuclear heat deposition and the manufacturing error of the cooling tube. The optimum helium gap width is selected to be 0.75 mm and the optimum cooling tube pitch of each row to be from 30 mm for the inner-most row to 70 mm for the outermost row. (author)