Materials optimisation for fusion power plants waste management from neutronics and activation assessment

The paper describes a study dedicated to the decommissioning and waste management issues of a commercial fusion power station. It is focused on the optimisation of structural materials for ex-vessel components of two safety and environmental assessment of fusion power (SEAFP) plant models (PM2 water-cooled and PM3 helium-cooled). The results of this study are: for PM2, the inboard and outboard coil case, the outboard vacuum vessel (VV), the outboard insulator and winding pack, the neutron and gamma shield and the concrete cryostat can be cleared; the same for PM3, excluding the outboard VV. Possible optimisations proposed are related to the outboard vessel both for PM2 and PM3. They deal with impurity level control and/or use OPTSTAB, a reduced-activation austenitic high-manganese steel.