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Journal Articles

Volume reduction of cesium contaminated soil by magnetic separation; Pretreatment of organic matters

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:1 Percentile:54.41

Journal Articles

Evaluation of inter-laminar shear strength of GFRP composed of bonded glass/polyimide tapes and cyanate-ester/epoxy blended resin for ITER TF coils

Hemmi, Tsutomu; Nishimura, Arata*; Matsui, Kunihiro; Koizumi, Norikiyo; Nishijima, Shigehiro*; Shikama, Tatsuo*

AIP Conference Proceedings 1574, p.154 - 161, 2014/01

 Times Cited Count:5 Percentile:89.73

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 $$gamma$$-ray and neutrons since the ITER TF coils is exposed by first neutron ($$>$$ 0.1 MeV) of 10$$^{22}$$ n/m$$^{2}$$ 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.

Journal Articles

Fission neutron irradiation effect on interlaminar shear strength of cyanate ester resin GFRP at RT and 77 K

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:52.1

A GFRP with cyanate ester resin was fabricated and neutron irradiation tests up to 1$$times$$10$$^{22}$$ n/m$$^{2}$$ 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 1$$times$$10$$^{21}$$ n/m$$^{2}$$ increased ILSS a little but 1$$times$$10$$^{22}$$ n/m$$^{2}$$ irradiation decreased ILSS to around 50 MPa. These tendencies were observed in all three kinds of GFRPs.

Journal Articles

Molecular analysis of carbon ion induced mutations in the yeast ${it ogg1}$ and ${it msh2}$ mutants

Matsuo, 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

Journal Articles

Study on molecular mechanism of high-LET carbon ion beam induced mutations in ${it S. cerevisiae}$

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

Journal Articles

Study of molecular mechanism of carbon ion beam induced mutations in the ${it Saccharomyces cerevisiae}$

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

Journal Articles

Change in properties of superconducting magnet materials by fusion neutron irradiation

Nishimura, Arata*; Nishijima, Shigehiro*; Takeuchi, Takao*; Nishitani, Takeo

Fusion Engineering and Design, 82(5-14), p.1555 - 1560, 2007/10

 Times Cited Count:5 Percentile:38.77(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$$_{3}$$Sn, Nb$$_{3}$$Al 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.

Journal Articles

Influence of diluent on radiolysis of amides in organic solution

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:69 Percentile:97.41(Chemistry, Physical)

The radiolytic behavior of ${it N,N,N',N'}$-tetraoctyldiglycolamide, ${it N,N'}$-dimethyl-${it N,N'}$-dioctyl-2-(3'-oxapentadecyl)malonamide, and ${it N,N}$-dioctylhexanamide in ${it n}$-dodecane was investigated by irradiation with $$gamma$$-rays and electron pulses. The results showed ${it n}$-dodecane has a sensitization effect on the radiolysis of these amides, owing mainly to a charge transfer from radical cations of ${it n}$-dodecane to the amide molecules in the primary process observed in pulse radiolysis.

Journal Articles

Study of molecular mechanism of ion beam induced mutations in the ${it Saccharomyces cerevisiae}$

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

Journal Articles

Specificity of mutations induced by carbon ions in budding yeast ${it Saccharomyces cerevisiae}$

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:26 Percentile:56.65(Biotechnology & Applied Microbiology)

no abstracts in English

Journal Articles

Irradiation effect of 14 MeV neutron on interlaminar shear strength of glass fiber reinforced plastics

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 $$gamma$$ 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 $$gamma$$ 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.

Journal Articles

Monte Carlo simulation of strand position in CIC Conductor

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:12.63(Engineering, Electrical & Electronic)

The strand position in CIC conductor consisting of 1,152(3$$times$$4$$times$$4$$times$$4$$times$$6) 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.

Oral presentation

Activation properties of Nb$$_{3}$$Sn, NbTi and GFRP irradiated with D-T neutrons

Ochiai, Kentaro; Nishimura, Arata*; Nishitani, Takeo; Nishijima, Shigehiro*

no journal, , 

Nb$$_{3}$$Sn, 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 Nb$$_{3}$$Sn, 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 Nb$$_{3}$$Sn and NbTi produced by FURUKAWA-electric Ltd. and a commercial GFRP (G10CR) plate. These samples were irradiated up to the neutron fluence of 4$$times$$10$$^{19}$$n/m$$^{2}$$ corresponding to about one twentieth neutron fluence expected for ITER life time. After the cooling time, the dose rates and the emitted $$gamma$$-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 Nb$$_{3}$$Sn, 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 Nb$$_{3}$$Sn, NbTi and GFRP samples were 160$$mu$$Sv/h, 120$$mu$$Sv/h and 20$$mu$$Sv/h, respectively. After 5 months from the irradiation, these dose rates were reduced to 2-4$$mu$$Sv/h. Also, from the measured $$gamma$$-ray spectra, it was found that the final dose rates of Nb$$_{3}$$Sn and NbTi wires were dominated by Co-60 (5.27y) and the that of GFRP was dominated by Na-22 (2.60y).

Oral presentation

Irradiation effect of D-T neutron on superconducting magnet materials for fusion

Nishimura, Arata*; Hishinuma, Yoshimitsu*; Seo, Kazutaka*; Tanaka, Teruya*; Muroga, Takeo*; Nishijima, Shigehiro*; Katagiri, Kazumune*; Takeuchi, Takao*; Shindo, Yasuhide*; Ochiai, Kentaro; et al.

no journal, , 

A fusion device which creates burning plasma will be equipped with a superconducting magnet system to provide strong magnetic field and maintain the burning plasma. The fusion device also will have plasma heating devices such as neutral beam injectors and electron cyclotron systems. Since these systems need several ports to carry in the energy into plasma, the fusion device has large ports connecting to the systems locates in outside of cryostat. Through these ports, D-T neutron will come out of the burning plasma and damage the surrounding materials. The superconducting magnets also will be irradiated by the streaming neutron. To investigate mechanisms of degradation of superconducting properties, and to construct database of irradiation effect on superconducting magnet materials, a cryogenic target system has been install in Fusion Neutronics Source (FNS) at Japan Atomic Energy Agency (JAEA). The irradiation tests with D-T neutron have been carried out three times and some irradiation effects on superconducting magnet materials are clarified. In this paper, the present status of the cryogenic target system and some irradiation test results will be summarized and presented.

Oral presentation

Molecular analysis of heavy ion induced mutations in budding yeast ${it Saccharomyces cerevisiae}$

Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Shimizu, Kikuo*

no journal, , 

no abstracts in English

Oral presentation

Mechanisms of mutation induction in budding yeast by heavy ion irradiation

Matsuo, Yoichiro*; Nishijima, Shigehiro*; Shimizu, Kikuo*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi

no journal, , 

no abstracts in English

Oral presentation

Analysis of molecular mechanism of mutations induced by heavy ion beams

Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Shimizu, Kikuo*

no journal, , 

no abstracts in English

Oral presentation

Relationship between mechanisms of mutation induction by heavy ion beam irradiation and nucleosome structure

Matsuo, Yoichiro*; Nishijima, Shigehiro*; Shimizu, Kikuo*; Hase, Yoshihiro; Sakamoto, Ayako; Narumi, Issei

no journal, , 

no abstracts in English

Oral presentation

Molecular analysis of carbon ion induced mutations in the budding yeast Saccharomyces cerevisiae

Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Yokota, Yuichiro; Sakamoto, Ayako; Narumi, Issei; Shimizu, Kikuo*

no journal, , 

no abstracts in English

Oral presentation

Analysis of mutagenesis mechanisms of budding yeast by carbon ion beam irradiation

Matsuo, Yoichiro*; Nishijima, Shigehiro*; Hase, Yoshihiro; Sakamoto, Ayako; Narumi, Issei; Shimizu, Kikuo*

no journal, , 

no abstracts in English

31 (Records 1-20 displayed on this page)