EVOLVE—an advanced first wall/blanket system

A new concept for an advanced fusion first wall and blanket has been identified. The key feature of the concept is the use of the heat of vaporization of lithium (about 10 times higher than water) as the primary means for capturing and removing the fusion power. A reasonable range of boiling temperatures of this alkali metal is 1200–1400°C, corresponding with a saturation pressure of 0.035–0.2 MPa. Calculations indicate that an evaporative system with Li at ≃1200°C can remove a first wall surface heat flux of >2 MW m−2 with an accompanying neutron wall load of >10 MW m−2. Work to date shows that the system provides adequate tritium breeding and shielding, very high thermal conversion efficiency, and low system pressure. Tungsten is used as the structural material, and it is expected to operate at a surface wall load of 2 MW m−2 at temperatures above 1200°C.