Comparison of first-wall damage in Cat-D and D-T Tokamaks

The reduced neutron flux and lower average energy characteristic of the Cat-D fusion cycle, compared to D-T, result in reduced first-wall damage. In order to compare first-wall lifetime expectations, neutron-induced damage and also surface erosion due to sputtering are evaluated for recent conceptual tokamak reactor designs employing Cat-D and D-T fuels. While neutron damage appears to limit the D-T first wall to ~7 years lifetime, the Cat-D wall is found to last 20 years or longer. While sputtering erosion is more severe for Cat-D, this does not appear restrictive with use of appropriate first-wall coating techniques.