The book contains information on the effect of neutron radiation on the physical and mechanical properties of materials used as fuel claddings, fuel assembly covers, reactor shells, various reactor core elements, etc. A very wide range of materials is used in the reactor industry. The book contains a list of alloys and steels used in reactor engineering as structural materials of nuclear power plants. In the course of work, the results of research on the effect of radiation on the steels and alloys of domestic nuclear reactors were collected, processed and analyzed.