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Ando, Masami; Tanigawa, Hiroyasu; Kurotaki, Hironori
no journal, ,
Reduced activation ferritic/martensitic steel (RAFM) is the most promising candidate for the blanket structural material in DEMO fusion reactor. Void swelling behavior as well as mechanical properties change under high dose fusion neutron irradiation is very important issue on R&D of RAFM steels (F82H). The purposes of this study are to investigate the void swelling behavior with F82H IEA, Mod-3 and BA07 heats after multi-ion-irradiation and to confirm the peak swelling temperature. From results of microstructure observation for F82H Mod-3 and BA07 heats at 470
C by multi-ion beam irradiation, cavities are observed from 0.8 to 1.2
m (damage level 
20 dpa) from an irradiation surface at 470C irradiated specimen. On the other hand, few cavities are observed in same region at 400C irradiation. This result shows that a swelling peak temperature with F82H weldments by ion irradiation will be also around 470C.
Ozawa, Kazumi; Taguchi, Tomitsugu; Kurotaki, Hironori; Nozawa, Takashi; Tanigawa, Hiroyasu
no journal, ,
A silicon carbide (SiC) matrix composite is a promising candidate for nuclear fusion energy applications. In order to examine the dimensional stability and microstructure of two kinds of high purity and near stoichiometric SiC fiber (Hi-Nicalon Type-S and Tyranno-SA3) after irradiation, which contain impurities compared to high crystalline and stoichiometric 
-SiC matrix, self-ion irradiation experiments at relatively lower temperatures were performed at TIARA and DuET facility. The properties after the irradiation were evaluated by means of AFM for dimensional stability and FE-TEM for microscopy. After ion irradiation at 600C to 100 dpa, shrinkage of Hi-Nicalon Type-S was obtained but the degree was smaller than the case for the irradiation at 300C to 100 dpa. Contrarily, the shrinkage of Tyranno-SA3 fiber appeared to be much smaller than the Hi-Nicalon Type-S fiber after each irradiation condition.
Ando, Masami; Tanigawa, Hiroyasu; Nozawa, Takashi; Hamaguchi, Dai; Kurotaki, Hironori
no journal, ,
Irradiation creep behavior of F82H and B-doped F82H was examined by several pressurized tubes after neutron irradiation. The irradiation creep strain in F82H irradiated at 573 and 673 K was almost linearly dependent on the effective stress level for stresses below 260 MPa and 170MPa, respectively. The creep strain of 10BN-F82H was similar to that of F82H IEA at each effective stress level except 294 MPa at 573 K irradiation. For 673 K irradiation, the creep strain of some 10BN-F82H tubes was larger than that of F82H tubes. Microstructure in hoop stress level 250 MPa after 573 K irradiation was similar to microstructure in not-pressurized tube. Precipitates (100 nm) also were observed along Lath and prior g-boundaries. On the other hands, large precipitations (
200 nm) were observed along the grain boundary after 773 K irradiation. Recovery of martensite structures and some cell structures were also observed.