ИСТИНА

Reduced Activation Ferritic/Martensitic (RAFM) steels such as Eurofer (EU), F82H (Japan), Rusfer EK-181 (Russia) are candidate materials for first wall and breeding blanket structural application in future fusion power plants. These steels have been developed in order to simplify special waste storage of highly radioactive structures of fusion reactor after service. With this objective some alloying elements such as Mo, Nb and Ni present in the commercial martensitic steels have been replaced by other elements such as Ta, W and V which exhibit faster decay of induced radioactivity. As probable blanket structural materials, the RAFM steels will be exposed to gaseous tritium bred in a blanket under neutron irradiation. A part of tritium implanted into an armor material from plasma will permeate to the RAFM steels. Besides, the use of bare RAFM steel as first-wall material in a fusion reactor, at least in selected areas of the main chamber, has been proposed recently. Therefore, study of hydrogen isotope retention in undamaged and damaged RAFM steels (i.e., in the steels as-received and in the steels with ion-induced displacement damages simulating neutron-induced defects) is an important issue for assessment of tritium retention in structural elements of fusion reactors.