Neutron damage comparison of fusion fuel cycles

The prediction of the property changes of structural materials after service in a fusion reactor is a key point for the technological development of fusion. The interaction of the fusion neutrons with the first wall, in particular, is a central problem. In fact, the neutron spectra in a fusion reactor will be higher and harder than those in fission reactors. Greater gas production and higher rates of displacement of atoms from their lattice sites are expected, with a detrimental effect on many material properties. The studies on fusion machines are mainly devoted to the deuterium-tritium (D-T) fuel cycle, which seems the easiest way to reach ignition. Many potential advantages, however, are achievable through the use of advanced fuel cycles, which eliminate the need to breed and fuel tritium and produce fewer neutrons, with better safety and activation characteristics. This paper shows that advanced fuel cycles are also preferable for neutron radiation damage. A comparison of some neutron damage phenomena at the first wall (gas production, displacements) is performed for a consistent set of three fusion reactor designs based on different fuel cycles (D-T, D-D, and D-He