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Okubo, Nariaki; Wakai, Eiichi; Matsukawa, Shingo*; Sawai, Tomotsugu; Kitazawa, Sin-iti; Jitsukawa, Shiro
Journal of Nuclear Materials, 367-370(1), p.107 - 111, 2007/08
Times Cited Count：6 Percentile：42.5(Materials Science, Multidisciplinary)no abstracts in English
Wakai, Eiichi; Otsuka, Hideo; Matsukawa, Shingo*; Ando, Masami; Jitsukawa, Shiro
JAEA-Technology 2006-019, 58 Pages, 2006/03
JAEA-Technology-2006-019.pdf:7.15MB
Small specimen test technology (SSTT) has been developed to investigate mechanical properties of nuclear materials. SSTT has been driven by limited availability of effective irradiation volumes in test reactors and accelerator-based neutron and charged particle sources, and it is very useful for the reduction of waste materials produced in nuclear engineering. In this study new bend test machines have been developed to obtain fracture behaviors of F82H steel for very small bend specimens of pre-cracked 
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CVN (Charpy V-notch) with 20 mm-length and DFMB (deformation and fracture mini bend specimen) with 9 mm-length and disk compact tension of 0.18DCT type, and fracture behaviors were examined to evaluate DBTT (ductile-brittle transition temperature) at temperatures from -180 to 250
C. The effect of specimen size on DBTT of F82H steel was also examined by using Charpy type specimens such as -CVN, CVN and -CVN. In this paper, it also provides the information of the specimens irradiated at 250C and 350C to about 2 dpa in the capsules of 04M-67A and 04M-68A of JMTR experiments.
Wakai, Eiichi; Otsuka, Hideo*; Matsukawa, Shingo; Furuya, Kazuyuki*; Tanigawa, Hiroyasu; Oka, Keiichiro*; Onuki, Somei*; Yamamoto, Toshio*; Takada, Fumiki; Jitsukawa, Shiro
Fusion Engineering and Design, 81(8-14), p.1077 - 1084, 2006/02
Times Cited Count：11 Percentile：60.27(Nuclear Science & Technology)no abstracts in English
Okubo, Nariaki; Wakai, Eiichi; Matsukawa, Shingo; Tanigawa, Hiroyasu; Sawai, Tomotsugu; Jitsukawa, Shiro; Onuki, Somei*
Materials Transactions, 46(8), p.1779 - 1782, 2005/08
Times Cited Count：1 Percentile：16.27(Materials Science, Multidisciplinary)no abstracts in English
Okubo, Nariaki; Wakai, Eiichi; Matsukawa, Shingo*; Furuya, Kazuyuki; Tanigawa, Hiroyasu; Jitsukawa, Shiro
Materials Transactions, 46(2), p.193 - 195, 2005/02
Times Cited Count：1 Percentile：16.27(Materials Science, Multidisciplinary)no abstracts in English
Taguchi, Tomitsugu; Jitsukawa, Shiro; Sato, Michitaka*; Matsukawa, Shingo*; Wakai, Eiichi; Shiba, Kiyoyuki
Journal of Nuclear Materials, 335(3), p.457 - 461, 2004/12
Times Cited Count：11 Percentile：58.51(Materials Science, Multidisciplinary)F82H (Fe-8Cr-2W) and its variant doped with 2%Ni were irradiated up to 20 dpa at 300C in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Post irradiation tensile testing was performed at room temperature. During testing, the images of the specimens including the necked region were continuously recorded. Tests on cold worked material were also carried out for comparison. From the load-displacement curves and the strain distributions obtained from the images, flow stress levels and strain hardening behavior was evaluated. A preliminary constitutive equation for the plastic deformation of irradiated F82H is presented. The results suggest that the irradiation mainly causes defect-induced hardening while it did not strongly affect strain hardening at the same flow stress level for F82H irradiated at 300C. The strain hardening of Ni doped specimens was, however, strongly affected by irradiation. Results provide basics to determine allowable stress levels at temperatures below 400C.
Ando, Masami; Wakai, Eiichi; Sawai, Tomotsugu; Matsukawa, Shingo; Naito, Akira*; Jitsukawa, Shiro; Oka, Keiichiro*; Tanaka, Teruyuki*; Onuki, Somei*
JAERI-Review 2004-025, TIARA Annual Report 2003, p.159 - 161, 2004/11
The objectives of this study are to evaluate radiation hardening on ion-irradiated F82H up to 100 dpa and to examine the extra component of radiation hardening due to implanted helium atoms (up to 
3000 appmHe) in F82H under ratio of 0, 10, 100 appmHe/dpa.The ion-beam irradiation experiment was carried out at the TIARA facility of JAERI. Specimens were irradiated at 633 K by 10.5 MeV Fe ions with/without 1.05 MeV He ions. Micro-indentation tests were performed at loads to penetrate about 0.40 mm in the irradiated specimens using an UMIS-2000. The results are summarized as follows:1) As a result of the single irradiated F82H, the micro-hardness tended to increase about 30 dpa. 2) The extra radiation hardening was obviously caused by co-implanted helium atoms more than 1000 appm in F82H irradiated at 633 K. 3) In the dual-beam (100 appmHe/dpa) irradiated microstructure, nano-voids and fine defects were observed. It is suggested that the formation of nano-voids causes the extra radiation hardening by helium co-implantation.
Wakai, Eiichi; Matsukawa, Shingo; Yamamoto, Toshio*; Kato, Yoshiaki; Takada, Fumiki; Sugimoto, Masayoshi; Jitsukawa, Shiro
Materials Transactions, 45(8), p.2641 - 2643, 2004/08
Times Cited Count：6 Percentile：41.12(Materials Science, Multidisciplinary)no abstracts in English
Wakai, Eiichi; Ando, Masami; Matsukawa, Shingo*; Yamamoto, Toshio; Takada, Fumiki
no journal, ,
no abstracts in English
