Development of ODS ferritic steels for fast reactor

Otsuka, Satoshi   ; Ukai, Shigeharu  ; Fujiwara, Masayuki; Kaito, Takeji ; Narita, Takeshi; Sakasegawa, Hideo   

Japan Atomic Energy Agency (JAEA) has gone ahead on with the research and development of the advanced type sodium (Na)-cooled fast reactors, and come to the conclusion that the high performance nuclear fuel resisting to high burn-up -250GWD/t: 250dpa- and high-temperature operation -700C- is indispensable for adequate economical operation. JAEA has developed a manufacturing process of the cladding tube made of 9CrODS martensitic steel (9CrODS), and accumulated knowledge by fabricating several hundred of the tube. These activities have led to the resounding success in establishing a fabrication process of the 9CrODS tube having the target creep strength of 700C120MPa (in hoop)10,000h. In recent years, our efforts have been made to develop a microstructure control technique that further improves the creep strength, a large scale manufacturing procedure, a database on environment effects including radiation damage and corrosion resistance, and so on. In addition, under the contribution to the Super ODS project sponsored by MEXT, the modification of the ODS steel has been started for the application to the high burn-up cladding tube of lead-bismuth eutectic (LBE)-cooled reactor and super critical pressurized water (SCW)-cooled reactor. In this presentation, we will report the current status on the 9CrODS development in JAEA, in particular the microstructure control procedure for high-temperature strength improvement as well as the compatibility of the 9CrODS steel with LBE.