A nuclear reactor comprising a reactor vessel and structural members

Abstract

A nuclear reactor having structural members made of austenitic stainless steel which is corrosion-resistant in an environment of neutron irradiation, and can suppress stress corrosion cracking and embrittlement. At least one additive selected from the group consisting of Ti more than 0.2% by weight but not more than 0.6%, Zr more than 0.2% but not more than 1.14%, Hf more than 0.2% but not more than 2.24%, V more than 0.2% but not more than 0.64%, Nb more than 0.5% but not more than 1.17% and Ta more than 0.5% but not more than 2.27% is added to austenitic stainless steel containing Cr, Ni and so on, and said at least one exists in a solid-solution state. In addition, the steel has a wholly austenitic structure substantially free of carbide. In order to maintain the irradiation-induced segregation prevention effected by the addition element, the C content is limited to 0.01 to 0.008%, and the N content is limited to 0.001 to 0.0%. The irradiation-induced segregation, of the constituent elements, such as Cr and Ni, occurring in a grain boundary under irradiation, can be prevented, and the deterioration of the corrosion resistance of the material, as well as the embrittlement, can be prevented.