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) SiC_f/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 SiC_f/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).