The reliability and operational lifetime of a number of units in fast-breeder and thermonuclear reactors must largely depend on the degree of the high-temperature radiation-induced embrittlement (HTRE) of materials under neutron irradiation. Many investigators [1-5] associate IITRE with the formation of helium in austenitic chrome--nickel and chrome--mangenese steels, in high-nickel alloys, in nickel, and in other metals and alloys due to the (n, ~) reactions. The sharp drop in plasticity and the intergrain nature of the rupture of specimens in tensile tests in the temperature range (0.5-0.6)Tmelt were observed also after irradiation of Specimens of the materials listed abo~e by ~ particle s with energies up to 40 MeV and with 225-MeV electrons, i.e., with the introduction of helium atoms.