Radiation damage studies on the first wall of a HYLIFE-II type fusion breeder

The radiation damage on the first wall [made of (1) a ferritic steel (9Cr–2WVTa), (2) a vanadium alloy (V–4Cr–4Ti) and (3) SiCf/SiC composite] of an inertial fusion energy (IFE) reactor of HYLIFE-II type is investigated. A protective liquid wall with variable thickness, containing Flibe + heavy metal salt (UF4 or ThF4) is used for first wall protection. The content of heavy metal salt is chosen as 4 and 12 mol%. Neutron transport calculations are performed with the aid of the SCALE4.3 System by solving the Boltzmann transport equation with the XSDRNPM code in 238 energy groups and S8–P3 approximation.A flowing wall with a thickness of ∼60 cm can extend the lifetime of the solid first wall structure to a plant lifetime of 30 years for 9Cr–2WVTa and V–4Cr–4Ti, whereas the SiCf/SiC composite as first wall needs a flowing wall with a thickness of ∼85 cm to maintain the radiation damage limit. Substantial extra revenue can be gained through the insertion of a heavy metal salt constituent into Flibe, which allows breeding fissile fuel for external reactors and increasing energy multiplication (233U with a value of up to 1,000,000,000 $/year or 239Pu for few 100,000,000 $/year).