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Journal Articles

Molecular geochemistry of radium; A key to understanding cation adsorption reaction on clay minerals

Yamaguchi, Akiko; Kurihara, Yuichi*; Nagata, Kojiro*; Tanaka, Kazuya; Higaki, Shogo*; Kobayashi, Toru; Tanida, Hajime; Ohara, Yoshiyuki*; Yokoyama, Keiichi; Yaita, Tsuyoshi; et al.

Journal of Colloid and Interface Science, 661, p.317 - 332, 2024/05

no abstracts in English

Journal Articles

Extended X-ray absorption fine structure spectroscopy measurements and ${it ab initio}$ molecular dynamics simulations reveal the hydration structure of the radium(II) ion

Yamaguchi, Akiko; Nagata, Kojiro*; Kobayashi, Keita; Tanaka, Kazuya; Kobayashi, Toru; Tanida, Hajime; Shimojo, Kojiro; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.

iScience (Internet), 25(8), p.104763_1 - 104763_12, 2022/08

 Times Cited Count:3 Percentile:54.33(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

Investigation of hydration and adsorption structures on clay minerals of radium by EXAFS

Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.

Hosha Kagaku, (45), p.28 - 30, 2022/03

no abstracts in English

Journal Articles

Evaluation of change of LSD spikes by long-term storage

Shibano, Koya; Abe, Katsuo; Tsukasa, Kazuo*; Hosogane, Tatsuya; Kayano, Masashi; Sumi, Mika; Fujiwara, Hideki*; Yamaguchi, Kazuya*; Motoki, Chika*

Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2020/11

Large-sized dried spikes, called LSD spike, are used as reference material for accountancy analysis for Plutonium and Uranium by Isotope Dilution Mass Spectrometry. LSD spikes preparation is performed each steps as followed (1) Preparing Plutonium and Uranium mix solution, (2) Aliquoting mix solution to vials, and (3) Drying. J-MOX have planned prepared in-house LSD spike and utilized it for accountancy analysis. If LSD spikes are stored for long term, dried material peel off from bottom of vial and it may affect analytical results. In this study, LSD spikes, which have composition suitable for accountancy analysis in J-MOX, had been stored for about 2 years, then long-term stability of LSD spikes had been evaluated.

JAEA Reports

Status of study of long-term assessment of transport of radioactive contaminants in the environment of Fukushima (FY2018) (Translated document)

Nagao, Fumiya; Niizato, Tadafumi; Sasaki, Yoshito; Ito, Satomi; Watanabe, Takayoshi; Dohi, Terumi; Nakanishi, Takahiro; Sakuma, Kazuyuki; Hagiwara, Hiroki; Funaki, Hironori; et al.

JAEA-Research 2020-007, 249 Pages, 2020/10

JAEA-Research-2020-007.pdf:15.83MB

The accident of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. occurred due to the Great East Japan Earthquake, Sanriku offshore earthquake, of 9.0 magnitude and the accompanying tsunami. As a result, large amount of radioactive materials was released into the environment. Under these circumstances, Japan Atomic Energy Agency (JAEA) has been conducting "Long-term Assessment of Transport of Radioactive Contaminants in the Environment of Fukushima" concerning radioactive materials released in environment, especially migration behavior of radioactive cesium since November 2012. This report is a summary of the research results that have been obtained in environmental dynamics research conducted by JAEA in Fukushima Prefecture.

JAEA Reports

Status of study of long-term assessment of transport of radioactive contaminants in the environment of Fukushima (FY2018)

Nagao, Fumiya; Niizato, Tadafumi; Sasaki, Yoshito; Ito, Satomi; Watanabe, Takayoshi; Dohi, Terumi; Nakanishi, Takahiro; Sakuma, Kazuyuki; Hagiwara, Hiroki; Funaki, Hironori; et al.

JAEA-Research 2019-002, 235 Pages, 2019/08

JAEA-Research-2019-002.pdf:21.04MB

The accident of the Fukushima Daiichi Nuclear Power Station (hereinafter referred to 1F), Tokyo Electric Power Company Holdings, Inc. occurred due to the Great East Japan Earthquake, Sanriku offshore earthquake, of 9.0 magnitude and the accompanying tsunami. As a result, large amount of radioactive materials was released into the environment. Under these circumstances, JAEA has been conducting Long-term Environmental Dynamics Research concerning radioactive materials released in environment, especially migration behavior of radioactive cesium since November 2012. This report is a summary of the research results that have been obtained in environmental dynamics research conducted by JAEA in Fukushima Prefecture.

Journal Articles

Study on criticality in natural barrier for disposal of fuel debris from Fukushima Daiichi NPS

Shimada, Taro; Takubo, Kazuya*; Takeda, Seiji; Yamaguchi, Tetsuji

Progress in Nuclear Science and Technology (Internet), 5, p.183 - 187, 2018/11

After fuel debris is removed from the reactor containment vessel at Fukushima Daiichi NPS (1F) and collected in waste containers in the future, the waste containers will be disposed at a deep geological repository. The uranium inventory and uranium-235 ($$^{235}$$U) enrichment of the fuel debris are larger than those of high-level vitrified wastes which are produced from liquid waste during reprocessing of spent nuclear fuels. Therefore, there is a possibility not to be excluded that a criticality occurs in the geological media where the uranium precipitates at the far-field from the repository, after the uranium located in the repository is dissolved by groundwater. In this study, we calculated the quantity of uranium precipitated at the natural barrier, and studied dimension of uranium deposited in the natural barrier and carried out the criticality analysis.

Journal Articles

Discovery of radiocesium-bearing microparticles in river water and their influence on the solid-water distribution coefficient ($$K_{rm d}$$) of radiocesium in the Kuchibuto River in Fukushima

Miura, Hikaru*; Kurihara, Yuichi*; Sakaguchi, Aya*; Tanaka, Kazuya; Yamaguchi, Noriko*; Higaki, Shogo*; Takahashi, Yoshio*

Geochemical Journal, 52(2), p.145 - 154, 2018/00

 Times Cited Count:45 Percentile:93.9(Geochemistry & Geophysics)

Solid-water distribution coefficient ($$K_{rm d}$$) of radiocesium in rivers is apparently increased due to the possible presence of highly radioactive radiocesium-bearing microparticles (CsMPs) in the solid phase. In this study, we evaluated the contribution of CsMPs to apparent Kd values. The ratio of the radioactivity of the separated CsMPs to the total radiocesium on fluvial suspended particles ranged from 0 to 46%. This means that the existence of CsMPs in fluvial suspended partcles did not change apparent Kd values in order magnitude.

Journal Articles

Discovery of ion-adsorption type deposits of rare earth elements (REE) in Southwest Japan with speciation of REE by extended X-ray absorption fine structure spectroscopy

Yamaguchi, Akiko*; Honda, Tasuku*; Tanaka, Masato*; Tanaka, Kazuya; Takahashi, Yoshio*

Geochemical Journal, 52(5), p.415 - 425, 2018/00

 Times Cited Count:11 Percentile:59.18(Geochemistry & Geophysics)

Ion-adsorption type REE deposits in weathered granite are main sources of REE essential for high-technology industries. However, these type deposits have not been searched in Japan. In this study, Bulk REE abundances (= REE$$_{TOT}$$), ion-exchangeable REE (= REE$$_{EX}$$) by ammonium chloride solution, and percentage of REE$$_{EX}$$ relative to REE$$_{TOT}$$ (= REE$$_{PER}$$) in fresh and weathered granite samples in Southwest Japan (i.e., Hiroshima and Shimane Prefectures) were determined. The REE$$_{TOT}$$ and REE$$_{PER}$$ were comparable to those of ion-adsorption type REE deposits in China. Extended X-ray adsorption fine structure (EXAFS) spectra of REE in original samples and samples after the extraction of ion-exchangeable REE showed that (i) REE in samples with high REE$$_{PER}$$ mainly forms outer-sphere complexes and (ii) the remaining REE in the rocks after the extraction forms inter-sphere complexes.

Journal Articles

Imidazolium cation based anion-conducting electrolyte membranes prepared by radiation induced grafting for direct hydrazine hydrate fuel cells

Yoshimura, Kimio; Koshikawa, Hiroshi; Yamaki, Tetsuya; Shishitani, Hideyuki*; Yamamoto, Kazuya*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Maekawa, Yasunari

Journal of the Electrochemical Society, 161(9), p.F889 - F893, 2014/06

 Times Cited Count:20 Percentile:59.91(Electrochemistry)

Graft-type anion-conducting electrolyte membranes (AEMs) with imidazolium cations on graft polymers were synthesized through radiation-induced graft polymerization of ${it N}$-vinylimidazole (NVIm) on poly(ethylene-co-tetrafluoroethylene) (ETFE) films, followed by ${it N}$-propylation and ion-exchange reactions. The ${it N}$-propylation proceeded quantitatively, whereas the ion-exchange reactions in 1 M KOH at 60$$^{circ}$$C were accompanied by partial $$beta$$-elimination of the imidazolium cations(AEM2), which exhibited an ion-exchange capacity (IEC) of 0.85 mmol g$$^{-1}$$ and ionic conductivity of 10 mS cm$$^{-1}$$. AEM2 showed alkaline stability at 60$$^{circ}$$C but it gradually degraded at 80$$^{circ}$$C for ca. 150 h. The copolymer-type AEM (AEM3) with an IEC of 1.20 mmol g$$^{-1}$$ was prepared through the copolymerization of NVIm with styrene on ETFE films, followed by the same ${it N}$-propylation and ion-exchange reactions. AEM3 was shown higher alkaline durability in 1 M KOH at 80$$^{circ}$$C. As a result, it exhibited higher conductivity ($$>$$10 mS cm$$^{-1}$$) for 250 h. Therefore, alkylimidazolium cations in copolymer grafts are a promising anion conducting group for alkaline-durable AEMs. A maximum power density of 75 mW cm$$^{-2}$$ is obtained for AEM3 in a direct hydrazine hydrate fuel cell.

Journal Articles

Counter-anion effect on the properties of anion-conducting polymer electrolyte membranes prepared by radiation-induced graft polymerization

Koshikawa, Hiroshi; Yoshimura, Kimio; Sinnananchi, W.; Yamaki, Tetsuya; Asano, Masaharu; Yamamoto, Kazuya*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Maekawa, Yasunari

Macromolecular Chemistry and Physics, 214(15), p.1756 - 1762, 2013/08

 Times Cited Count:14 Percentile:43.43(Polymer Science)

Graft-type anion-conducting polymer electrolyte membranes were prepared by the radiation-induced graft polymerization of chloromethylstyrene into poly(ethylene-co-tetrafluoroethylene) (ETFE) films and subsequent quaternization with trimethylamine to evaluate the counter anion effects on fuel cell properties. The hydroxide form was maintained in -saturated water to prevent the bicarbonate formation. The hydroxide form showed conductivity and water uptake four and two times higher than the chloride and bicarbonate forms. The hydroxide form is thermally and chemically less stable, resulting in the tendency to absorb water and to convert to the bicarbonate form.

Journal Articles

Thermal imaging of standing spin waves

An, Toshu*; Yamaguchi, Kazuya*; Uchida, Kenichi*; Saito, Eiji

Applied Physics Letters, 103(5), p.052410_1 - 052410_3, 2013/07

 Times Cited Count:6 Percentile:27.02(Physics, Applied)

Journal Articles

Unidirectional spin-wave heat conveyer

An, Toshu*; Vasyuchka, V. I.*; Uchida, Kenichi*; Chumak, A. V.*; Yamaguchi, Kazuya*; Harii, Kazuya; Oe, Junichiro*; Jungfleisch, M. B.*; Kajiwara, Yosuke*; Adachi, Hiroto; et al.

Nature Materials, 12(6), p.549 - 553, 2013/06

 Times Cited Count:122 Percentile:96.36(Chemistry, Physical)

JAEA Reports

The International Atomic Energy Agency Nuclear Energy Management School 2012

Ohgama, Kazuya; Ando, Yoko; Yamaguchi, Mika; Ikuta, Yuko; Shinohara, Nobuo; Murakami, Hiroyuki; Yamashita, Kiyonobu; Uesaka, Mitsuru*; Demachi, Kazuyuki*; Komiyama, Ryoichi*; et al.

JAEA-Review 2013-004, 76 Pages, 2013/05

JAEA-Review-2013-004.pdf:13.53MB

JAEA together with the Japan Nuclear Human Resource Development Network (JN-HRD Net), the University of Tokyo (UT) and the Japan Atomic Industrial Forum (JAIF) cohosted the IAEA-Nuclear Energy Management School in Tokai Village, aiming that Japan will be the center of nuclear HRD in the Asian region. In the school, not only lectures by IAEA experts, but also lectures by Japanese experts and technical visits were included for foreign participants. The school contributed to the internationalization of Japanese young professionals, development of nuclear human resource of other countries, and enhancement of cooperation between IAEA and Japan. Additionally, collaborative relationship within JN-HRD Net was strengthened by the school. In this report, findings obtained during the preparatory work and the school period are reported for future international nuclear HRD activities in Japan.

Journal Articles

Structure of water from ambient to 4 GPa revealed by energy-dispersive X-ray diffraction combined with empirical potential structure refinement modeling

Yamaguchi, Toshio*; Fujimura, Koji*; Uchi, Kazuya*; Yoshida, Koji*; Katayama, Yoshinori

Journal of Molecular Liquids, 176, p.44 - 51, 2012/12

 Times Cited Count:18 Percentile:55.75(Chemistry, Physical)

X-ray diffraction measurements in an energy-dispersive mode have been made on water under various thermodynamic conditions of 298 K/30 MPa, 473 K/30 MPa and 573 K/30 MPa on a laboratory X-ray diffractometer. All the X-ray structure factors as well as those of water already measured at 298 K/1 GPa, 473 K/0.35 GPa and 486 K/4 GPa by using synchrotron X-ray radiation were subjected to empirical potential structure refinement (EPSR) modeling to reveal the detailed hydrogen bonding features in terms of partial pair correlation function, coordination number and three-dimensional spatial density function as a function of temperature and pressure. It has been shown to what extent the tetrahedral hydrogen-bonded network of water is perturbed by pressure and temperature.

Journal Articles

Alkaline durable anion exchange membranes based on graft-type fluoropolymer films for hydrazine hydrate fuel cell

Yoshimura, Kimio; Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari; Yamamoto, Kazuya*; Shishitani, Hideyuki*; Asazawa, Koichiro*; Yamaguchi, Susumu*; Tanaka, Hirohisa*

ECS Transactions, 50(2), p.2075 - 2081, 2012/10

no abstracts in English

Journal Articles

Pressure drop characteristic of the ITER cable-in-conduit conductor

Hamada, Kazuya; Kawano, Katsumi; Ebisawa, Noboru; Nakajima, Hideo; Yano, Yoshitaka*; Yamaguchi, Takanori*

Proceedings of 24th International Cryogenic Engineering Conference (ICEC 24) and International Cryogenic Materials Conference 2012 (ICMC 2012) (CD-ROM), p.559 - 562, 2012/05

The Japan Atomic Energy Agency (JAEA) has the responsibility to procure 25% of the ITER Toroidal Field Coil conductors and 100% of Central Solenoid Conductor as the Japanese Domestic Agency (JADA) in the ITER project. The TF conductor is composed of 900 Nb$$_{3}$$Sn superconducting strands and 522 Cu strands protected by a circular sheath tube (jacket) with an outer diameter of 43.7 mm. The TF conductor has a central spiral cooling tube and a coolant flows into the cable space and the central channel in parallel. JAEA has measured a pressure drop characteristic of more than 20 TF conductors having different length using nitrogen gas at room temperature as a part of acceptance test. The measurement results are normalized to friction factor as a function of Reynolds number to check the difference of each other. The results show the normalized pressure drop characteristic is same among conductors. This is one of evidences that TF conductor is manufactured uniformly.

Journal Articles

Development of laser cutting technology for reactor decommissioning process

Kobayashi, Kojiro*; Ida, Toshio*; Yamaguchi, Takeshi*; Daido, Hiroyuki; Muramatsu, Toshiharu; Sano, Kazuya; Tsuboi, Akihiko*; Shamoto, Hideyasu*; Ikeda, Takeshi*

Reza Kako Gakkai-Shi, 19(1), p.63 - 67, 2012/03

Laser cutting method, is that the metal melted by laser power is removed by assist gas, has some advantages which are high speed cutting and narrow line-width cutting for the thin metal. We has conducted the joint research with the relevant organizations on the R&D of the laser cutting technology for cutting stainless and carbon steel of over the 150 mm thickness which is maximum thickness of core structure in Fugen. We report the R&D plan and the current status of the laser cutting test.

Journal Articles

Laser cutting technologies under water for the nuclear reacter dismantlement

Kobayashi, Kojiro*; Ida, Toshio*; Yamaguchi, Takeshi*; Daido, Hiroyuki; Muramatsu, Toshiharu; Sano, Kazuya; Tsuboi, Akihiko*; Shamoto, Hideyasu*; Ikeda, Takeshi*

Yosetsu Gijutsu, 59(7), p.64 - 69, 2011/07

no abstracts in English

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:176 Percentile:99.41(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

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