High performance PbLi blanket

A novel blanket concept is described. The proposed design Is a dual coolant concept based on ferritic steel as structural material using helium to cool the first wall. The temperature of the entire steel structure is maintained below the 550/spl deg/C limit. The breeding zone is cooled by circulating the liquid metal breeder to external heat exchangers. Flow channel inserts are employed in the poloidal liquid breeder ducts, serving both as electrical and thermal insulator between the flowing liquid metal and the steel structure. In this way, a liquid metal exit temperature of about 700/spl deg/C is achievable, allowing either an advanced Rankine steam cycle or closed-cycle helium gas turbine (Brayton cycle) as the power conversion system. A gross thermal efficiency of about 45% can be achieved with either system.