Assessment of mechanical properties of neutron irradiated tungsten and its alloys

Tungsten (W) is the main candidate material for plasma-facing components (PFCs) armor in nuclear fusion reactors. In the magnetic confinement reactor called “Tokamak”, the confined hot plasma is directed by the magnetic field to the divertor component in order to remove the impurities and He ash. In addition, the fast neutrons generated from D-T reactions irradiate the surrounding components in the reactor’s vacuum chamber. As a result, the divertor component receives a high heat flux and a high neutron flux at the same time. In order to assess and design a divertor with the ability to endure such a harsh environment, the investigation of mechanical degradation after high-temperature neutron irradiation is required.Twelve W grades are investigated, including Plansee (Austria) ITER specification W and recrystallized W, A.L.M.T. (Japan) ITER specification W, AT&M (China) ITER specification W, A.L.M.T. (Japan) K doped W, A.L.M.T. (Japan) K doped W - 3 wt% Re alloy, KIT (Germany) K doped heavily deformed tungsten, fine grain pure W from IPP (Czech Rep.) produced by spark plasma sintering, two products strengthened by 1 wt% TiC and 2 wt% Y2O3 particles from KIT (Germany) produced by powder injection molding, rolled W strengthened by 0.5 wt% ZrC from ISSP (China), and single crystal W produced by MaTeck (Germany). The neutron irradiation is performed in the Belgian materials testing reactor (BR2) in Mol, Belgium. The highest irradiation temperature and irradiation dose are designed to be 1200 oC and ~1 dpa, which are close to the expected normal operation temperature and highest dose of the divertor in the first nuclear phase of ITER.