Development of high chromium ferritic heat resistant steels for power plants

The recent developments of ferritic heat resistant steels of high chromium content are reviewed. The high chromium ferritic steels for boilers of the coal fueled thermal power plants are described with regard to their composition, creep strength at high temperature and possible heat treatments. The development of modified SUS 316 steel for FBRs is described with its composition, heat treatments and other mechanical properties. It shall be employed for the wrapper tubes and fuel claddings. The applicability of SUS 316 and HT 9 steels to the first wall material of fusion reactors are discussed. (J.P.N.)