[en] On LWR, for most of fuel materials such as covered tubes, and so on, zirconium alloys such as zircaloy are used for a long term and without any large trouble. On metal materials used for nuclear reactors, especially nuclear fuels, their survey was begun from about 1946, in U.S.A. For this, it was essential conditions to endure corrosion at high temperature for a long time, to keep their quality even after strong irradiation, to absorb no neutron required for nuclear fission reaction, and so on. Here was described their histories from their birth and infancy periods to mass-production on about 1975, at a center of development of zirconium alloys in U.S.A. and Japan. (K.G.)