Nuclear energy systems and functional materials

At the time of developing the processes related to nuclear energy systems, it is desirable to search anew for the materials that meet advanced and diversified needs and possess various functions. The functions of materials are classified into mechanical, chemical, electronic and electric, magnetic, thermal, optical, living body and radiation functions. These functions are briefly explained. Various materials and the examples of their uses are shown. The functional materials which have been researched recently in atomic energy field are listed. As the recent trend, functionally gradient materials and the utilization of quantum beam are reported. As for the functional materials in nuclear power field, those for uranium enrichment, nuclear reactors, Purex process, MOX fuel manufacture, high level waste treatment and disposal and others are explained in relation to nuclear fuel cycle. The functional materials for nuclear power plants aim mainly at improving the reliability, and those aiming at improving the economic efficiency are few. The low Co material for controlling the generation of radioactive corrosion products and the corrosion-resistant steel for improving the reliability of steam generator tubes have been applied. The concrete examples of the application of new functional materials to nuclear power plants are reported. (K.I.)