Tungsten for use in fusion reactors

Results on hydrogen retention in tungsten obtained under controlled laboratory experimental conditions at the University of Toronto, in the framework of the IAEA Coordinated Research Project on 'Tritium Inventory in Fusion Reactors', are presented. The experiments include: (i) hydrogen retention in both polycrystalline tungsten (PCW) and single crystal tungsten (SCW) due to single species H+ or D+ irradiation and (ii) hydrogen and helium trapping in PCW due to simultaneous He+ and H+(D+) irradiation. The effects of various parameters on D retention in W were studied: specimen temperature; ion energy, fluence and flux; bulk and surface impurity concentrations; cumulative ion damage due to prior D+ irradiations; and C+ implantation prior to D+ irradiation. (author)