Roles and requirements of the blanket system of fusion power reactors

Roles and requirements of the blanket system of the fusion power reactors are discussed from viewpoints of economics, fuel supply, generation system, maintenance, radioactive waste, and interaction with the plasma core. As the blanket system influences the cost of the fusion energy, the blanket system must be designed to minimize the fusion energy cost. Tritium breeding performance of the blanket is indispensable role to show the advantage of fusion energy on energy security. Material development for high temperature use under high neutron flux is one of the key issues of the generation system because the thermal efficiency depends on the coolant temperature of the blanket. Innovative maintenance technologies such as dividable super-conducting coil system are very effective to make the fusion power reactor attractive. From viewpoints of natural resources and waste management, materials used in the fusion reactors should be recycled. Material selection is also of a large importance on the cost of radioactive waste disposal. Finally, it must be paid a careful attention that the design of the blanket system is inseparable from the achievement of a high performance plasma core. (author)