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Horie, Hiroki*; Yukumatsu, Kazuki*; Mishima, Fumihito*; Akiyama, Yoko*; Nishijima, Shigehiro*; Sekiyama, Tomio*; Mitsui, Seiichiro; Kato, Mitsugu
Journal of Physics; Conference Series, 871, p.012102_1 - 012102_7, 2017/07
Times Cited Count：2 Percentile：63.52(Physics, Applied)Hemmi, Tsutomu; Nishimura, Arata*; Matsui, Kunihiro; Koizumi, Norikiyo; Nishijima, Shigehiro*; Shikama, Tatsuo*
AIP Conference Proceedings 1574, p.154 - 161, 2014/01
Times Cited Count：9 Percentile：93.81(Thermodynamics)Japan Atomic Energy Agency (JAEA), as Japan Domestic Agency, has responsibility to procure 9 ITER Toroidal Field (TF) coils. The insulation system of the ITER TF coils consists of 3 layers of insulations, which are a conductor insulation, a double-pancake (DP) insulation and a ground insulation, composed of multi-layer glass/polyimide tapes impregnated a resin. The ITER TF coils are required to withstand an irradiation of 10 MGy from 
-ray and neutrons since the ITER TF coils is exposed by first neutron (
0.1 MeV) of 10
n/m
during the operation of 20 years in the ITER. Cyanate-ester/epoxy blended resins and bonded glass/polyimide tapes are developed as insulation materials to realize the required radiation-hardness for the insulation of the ITER TF coils. To evaluate the radiation-hardness of the developed insulation materials, the inter-laminar shear strength of glass-fiber reinforced plastics (GFRP) fabricated using developed insulation materials is measured as one of most important mechanical properties before/after the irradiation in a fission reactor of JRR-3. As a result, it is demonstrated that the GFRPs using the developed insulation materials have a sufficient performance to apply the ITER TF coil insulation.
Nishimura, Arata*; Izumi, Yoshinobu*; Nishijima, Shigehiro*; Hemmi, Tsutomu; Koizumi, Norikiyo; Takeuchi, Takao*; Shikama, Tatsuo*
AIP Conference Proceedings 1219, p.127 - 134, 2010/04
Times Cited Count：1 Percentile：48.58(Materials Science, Multidisciplinary)A GFRP with cyanate ester resin was fabricated and neutron irradiation tests up to 1
10 n/m of fast neutron with over 0.1 MeV energy were carried out in fission reactor. The fabrication process of cyanate ester GFRP was established and a collaboration network to perform investigations on irradiation effect of superconducting magnet materials was constructed. Three kinds of samples were fabricated. The first was CTD403 GFRP made by NIFS, the second was (cyanate ester + epoxy) GFRP provided by Toshiba, and the last was CTD403 GFRP made by Toshiba. The irradiation was carried out at JRR-3 in Japan Atomic Energy Agency using Rabbit capsules. After the irradiation, short beam tests were conducted at room temperature and 77 K and interlaminar shear strength (ILSS) was evaluated. The irradiation of 110
n/m increased ILSS a little but 110 n/m irradiation decreased ILSS to around 50 MPa. These tendencies were observed in all three kinds of GFRPs.
and 
mutantsMatsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Nozawa, Shigeki; Sakamoto, Ayako; Narumi, Issei; Shimizu, Kikuo*
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 75, 2009/12
no abstracts in English
Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Narumi, Issei; Shimizu, Kikuo*
JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 60, 2008/11
no abstracts in English
Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Yokota, Yuichiro; Narumi, Issei; Shimizu, Kikuo*
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 86, 2008/03
no abstracts in English
Nishimura, Arata*; Nishijima, Shigehiro*; Takeuchi, Takao*; Nishitani, Takeo
Fusion Engineering and Design, 82(5-14), p.1555 - 1560, 2007/10
Times Cited Count：6 Percentile：40.61(Nuclear Science & Technology)Recent researches on fusion reactor show neutron streaming from ports to outside of plasma vacuum vessels and neutron penetration through blanket and a neutron shielding structure. Therefore, superconducting magnet system in a fusion reactor will be irradiated by high energy particles. To evaluate the irradiation effect of fusion neutron on the superconducting magnet materials, a cryo-target system was constructed and installed at FNS/JAEA. The Nb
Sn, NbAl samples and copper wires were cooled down to 4.5 K by a GM refrigerator and irradiation tests by 14 MeV neutron at cryogenic temperature were carried out. Change in electric resistance and critical temperatures were measured after irradiation. On the outside of the cryostat, GFRP and other sensors were arranged and irradiated at the same time. After the irradiation, the properties of those materials were investigated and the difference was discussed.
Sugo, Yumi; Izumi, Yoshinobu*; Yoshida, Yoichi*; Nishijima, Shigehiro*; Sasaki, Yuji; Kimura, Takaumi; Sekine, Tsutomu*; Kudo, Hiroshi*
Radiation Physics and Chemistry, 76(5), p.794 - 800, 2007/05
Times Cited Count：83 Percentile：97.39(Chemistry, Physical)The radiolytic behavior of 
-tetraoctyldiglycolamide, 
-dimethyl--dioctyl-2-(3'-oxapentadecyl)malonamide, and 
-dioctylhexanamide in 
-dodecane was investigated by irradiation with -rays and electron pulses. The results showed -dodecane has a sensitization effect on the radiolysis of these amides, owing mainly to a charge transfer from radical cations of -dodecane to the amide molecules in the primary process observed in pulse radiolysis.
Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Shimizu, Kikuo*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 76, 2007/02
no abstracts in English
Matsuo, Yuichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Shimizu, Kikuo*
Mutation Research; Fundamental and Molecular Mechanisms of Mutagenesis, 602(1-2), p.7 - 13, 2006/12
Times Cited Count：32 Percentile：59.81(Biotechnology & Applied Microbiology)no abstracts in English
Nishimura, Arata*; Hishinuma, Yoshimitsu*; Seo, Kazutaka*; Tanaka, Teruya*; Muroga, Takeo*; Nishijima, Shigehiro*; Katagiri, Kazumune*; Takeuchi, Takao*; Shindo, Yasuhide*; Ochiai, Kentaro; et al.
AIP Conference Proceedings 824, p.241 - 248, 2005/09
Design activity of International Thermonuclear Experimental Reactor clarifies intense neutron streaming from ports for neutral beam injectors. Energy spectrum of the streaming is very wide and 14 MeV neutron and ray are the typical radiations. Large amount of glass fiber reinforced plastics will be used in a superconducting magnet system as an electric insulation material and a support structure, for such organic material is easy to manufacture, and light and cheap. In this report, effects of 14 MeV neutron and ray irradiation on interlaminar shear strength and fracture mode are investigated using G-10CR small specimen of which configuration was proposed as a standard for evaluation of the interlaminar shear strength.
Aoki, Kosuke*; Izumi, Yoshinobu*; Nishijima, Shigehiro*; Okuno, Kiyoshi; Koizumi, Norikiyo
IEEE Transactions on Applied Superconductivity, 13(2), p.1744 - 1747, 2003/06
Times Cited Count：1 Percentile：12.15(Engineering, Electrical & Electronic)The strand position in CIC conductor consisting of 1,152(34446) strands was analytically evaluated using Monte Carlo method. During the conductor fabrication, the conduit was compressed with the cable to fix the size and shape from one end. This makes the strands to be stretched along the axis. In the calculation, such manufacturing process was simulated. In addition, the contact energy between strands and the strain energy in the strands are considered. The calculation results show that the strands are moved by compressing the conduit. By this calculation, not only strand positions but also the distribution of contact stress between strands could be evaluated.
Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Narumi, Issei; Shimizu, Kikuo*
no journal, ,
no abstracts in English
Matsuo, Yoichiro*; Nishijima, Shigehiro*; Sakamoto, Ayako; Shimizu, Kikuo*
no journal, ,
no abstracts in English
Nishimoto, Yuki*; Horie, Hiroki*; Akiyama, Yoko*; Nishijima, Shigehiro*; Mitsui, Seiichiro; Umezawa, Katsuhiro; Kato, Mitsugu; Okada, Takashi; Sekiyama, Tomio*
no journal, ,
By the accident of Fukushima Daiichi Nuclear Power Plant, a large amount of soil was contaminated by radioactive cesium. We developed a new physical treatment method using magnetic separation that can separate high-dose 2:1 type clay minerals from contaminated soil selectively. However, there is an issue that it is difficult to capture 2:1 type clay minerals efficiently, because clay minerals form aggregations with soil organic matter. Our previous study indicated that aggregates can be dispersed effectively by treatment of organic matter with K
CO solution. The purpose of this study is to assess the effect of the organic matter treatment on efficiency improvement of magnetic separation for 2:1 type clay minerals. The result showed that the possibility of effective treatment method for the soil rich in organic matter like agricultural soil by combination of the pretreatment with KCO solution and magnetic separation.
Horie, Hiroki*; Akiyama, Yoko*; Mishima, Fumihito*; Nishijima, Shigehiro*; Mitsui, Seiichiro; Umezawa, Katsuhiro; Kato, Mitsugu; Okada, Takashi; Sekiyama, Tomio*
no journal, ,
A technique for volume reduction and recycle of cesium contaminated soil in combination with wet classification and high gradient magnetic separation was investigated. The magnetic separation can fractionate the fine soil particles (silt and clay) into high-dose and low-dose soil. This method utilizes the phenomenon that paramagnetic 2:1 clay strongly adsorbs cesium whereas diamagnetic 1:1 clay has low adsorption ability of cesium. One of the main issues in this technique is that the soil components are aggregated by organic matters, which prevents 2:1 type clay minerals from selective separation. In this study, pretreatment of the soil by KCO solution was conducted, prior to the magnetic separation, in order to disperse aggregates. As a result, further selective separation for 2:1 type clay minerals by the pretreatment was confirmed.
Shimizu, Kikuo*; Matsuo, Yoichiro*; Izumi, Yoshinobu*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Narumi, Issei
no journal, ,
no abstracts in English
Nishijima, Shigehiro*; Yukumatsu, Kazuki*; Horie, Hiroki*; Nomura, Naoki*; Akiyama, Yoko*; Mishima, Fumihito*; Sekiyama, Tomio; Mitsui, Seiichiro; Kato, Mitsugu
no journal, ,
The amount of Cs contaminated soil originating from decontamination work after the accident of Fukushima Dai-ichi Nuclear Power Plant is estimated as large as 20 million m
in maximum, and its volume reduction is required to optimize final disposal of the contaminated soil outside Fukushima pref. We have proposed a new method to reduce the volume of the contaminated soil by the combination of wet classification and high gradient magnetic separation (HGMS). In this study, we have been investigating selective separation of paramagnetic 2:1 type clay minerals and mica, which strongly absorb and fix Cs ions, by superconducting magnetic separation on silt/clay suspension as a volume reduction technique. We conducted magnetic separation experiments of contaminated soil in Fukushima utilizing a superconducting magnet based on results of particle trajectory simulation for various particle size.
Sn, NbTi and GFRP irradiated with D-T neutronsOchiai, Kentaro; Nishimura, Arata*; Nishitani, Takeo; Nishijima, Shigehiro*
no journal, ,
NbSn, NbTi wires and glass fiber reinforced plastics (GFRP) are prospective candidate materials of the superconducting coil assembly for fusion reactors. These materials are activated by D-T neutrons penetrating through the reactor core. From the radioactive waste point of view, it is important to investigate the activation properties for these candidate materials. However, no experiment has been done to investigate the activation properties for these materials. Therefore, we have carried out the experimental investigation of the activation properties of NbSn, NbTi wires and GFRP materials. The neutron irradiation experiment has been done by the FNS D-T neutron source of JAEA. We used complex multi-filaments wires of NbSn and NbTi produced by FURUKAWA-electric Ltd. and a commercial GFRP (G10CR) plate. These samples were irradiated up to the neutron fluence of 410
n/m corresponding to about one twentieth neutron fluence expected for ITER life time. After the cooling time, the dose rates and the emitted -ray spectra were measured with a survey meter and a Ge detector, respectively. Induced major radioactive nuclides are Nb-92m, Sn-117m, Sn-113 and Co-60 for NbSn, and Nb-92m, Sc-46 and Co-60 for NbTi. Also Na-24, Na-22, Sc-47, Co-57, As-74, Rb-83, Mn-54 and some unknown radioactive nuclides were observed from the irradiated GFRP. It is considered that those radioactive elements are due to the activation of the additive compounds in GFRP. The initial dose rates of the irradiated NbSn, NbTi and GFRP samples were 160
Sv/h, 120Sv/h and 20Sv/h, respectively. After 5 months from the irradiation, these dose rates were reduced to 2-4Sv/h. Also, from the measured -ray spectra, it was found that the final dose rates of NbSn and NbTi wires were dominated by Co-60 (5.27y) and the that of GFRP was dominated by Na-22 (2.60y).
Nishijima, Shigehiro*; Akiyama, Yoko*; Yukumatsu, Kazuki*; Horie, Hiroki*; Mishima, Fumihito*; Sekiyama, Tomio*; Mitsui, Seiichiro; Kato, Mitsugu
no journal, ,
By the Fukushima Daiichi Nuclear Power Plant accident, a large amount of soil was contaminated by radioactive Cs, and effective volume reduction techniques have been required to optimize final disposal of the contaminated soil outside Fukushima pref. We focused on the phenomenon that Cs ions are strongly adsorbed on paramagnetic 2:1 type clay minerals, and tried to separate 2:1 type clay minerals selectively by the combination of classification and magnetic separation. In this study, we conducted magnetic separation experiments of actual contaminated soil in Fukushima utilizing a superconducting magnet, based on the simulated results of 2:1 type clay minerals with each particle size. Based on the result, we proposed a new method for volume reduction of Cs contaminated soil.
