Tensile property changes of 11Cr ferritic/martensitic steel irradiated in Joyo

Tanno, Takashi  ; Yano, Yasuhide  ; Sekio, Yoshihiro  ; Oka, Hiroshi   ; Otsuka, Satoshi   ; Kaito, Takeji ; Tachi, Yoshiaki  

Ferritic/martensitic (F/M) steels are candidate for core material of fast reactors (FR) because of its superior swelling resistance. A 11Cr F/M steel (PNC-FMS) have been developed for wrapper tube and cladding tube of demonstration FR in Japan Atomic Energy Agency. For demonstration of in-reactor performance and preparation of material strength standard, it is important to extend database on irradiation and thermal aging effects. In this work, ring tensile tests and hardness tests of PNC-FMS irradiated in Joyo up to 32.5 dpa at 455-835 C were carried out, and the results were compared with those of aging tests in order to clarify the irradiation effects exclusive of thermal aging effects. The UTS at RT of PNC-FMS irradiated at over 600 C tended to be lower than those of as-received and/or thermal aged ones. The hardness showed the same trend. But, the UTS and hardness test results showed that PNC-FMS irradiated at 835 C could be harder than that of aged one.