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Narita, Hirokazu*; Maeda, Motoki*; Tokoro, Chiharu*; Suzuki, Tomoya*; Tanaka, Mikiya*; Shiwaku, Hideaki; Yaita, Tsuyoshi
RSC Advances (Internet), 13(25), p.17001 - 17007, 2023/06
no abstracts in English
Maeda, Tsuyoshi
Hoken Butsuri (Internet), 54(4), p.220 - 221, 2019/12
no abstracts in English
Maeda, Tsuyoshi; Endo, Yuya; Uezu, Yasuhiro
Hoken Butsuri (Internet), 54(3), p.177 - 180, 2019/10
no abstracts in English
Narita, Hirokazu*; Maeda, Motoki*; Tokoro, Chiharu*; Suzuki, Tomoya*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi
Analytical Sciences, 33(11), p.1305 - 1309, 2017/11
Times Cited Count:9 Percentile:41.1(Chemistry, Analytical)Maeda, Motoki*; Narita, Hirokazu*; Tokoro, Chiharu*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi
Separation and Purification Technology, 177, p.176 - 181, 2017/04
Times Cited Count:21 Percentile:59.21(Engineering, Chemical)Maeda, Toshikatsu; Chiba, Noriaki; Tateishi, Tsuyoshi*; Yamaguchi, Tetsuji
Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(2), p.158 - 164, 2013/06
no abstracts in English
Maeda, Hiroki*; Ishiguro, Yuki*; Honda, Takashi*; Jung, J.-S.*; Michimura, Shinji*; Inami, Toshiya; Kimura, Tsuyoshi*; Wakabayashi, Yusuke*
Journal of the Ceramic Society of Japan, 121(3), p.265 - 267, 2013/03
Times Cited Count:3 Percentile:25.91(Materials Science, Ceramics)Structural deformation of a magnetocapacitive material SmMnO was studied by X-ray diffraction measurement in a magnetic field. This antiferromagnetic material shows a jump in dielectric constant at 9 K only when a magnetic field of a few tesla is applied. In-field X-ray diffraction measurements clarified that there is no sudden change in structure that involves atomic displacement within the c-plane in Pbnm notation, while the antiferromagnetic phase transition at 60 K gives rise to a noticeable rotation of the MnO octahedra. This rotation occurs to maximize the energy gain through the exchange interaction.
Ishimi, Akihiro; Katsuyama, Kozo; Maeda, Koji; Nagamine, Tsuyoshi; Asaka, Takeo; Furuya, Hirotaka
Journal of Nuclear Science and Technology, 49(12), p.1144 - 1155, 2012/12
Times Cited Count:8 Percentile:52.71(Nuclear Science & Technology)no abstracts in English
Ichikawa, Shoichi; Haga, Hiroyuki; Kikukawa, Kiyohide*; Fukasaku, Hironobu*; Kurosawa, Yoichi*; Katsuyama, Kozo; Maeda, Koji; Nagamine, Tsuyoshi
JAEA-Technology 2011-020, 32 Pages, 2011/07
Disassembling technique of the driver fuel assembly irradiated in the experimental fast reactor JOYO has been established at Fuel Monitoring Facility in JAEA. This technique made it possible to remove the fuel pins from the driver fuel assembly without the fuel pin sectioning. After disassembling the fuel assembly, some selected fuel pins can be reassembled into the new irradiation vehicle for the continuous irradiation at JOYO. This technique enables us to obtain the irradiation data of high burn-up fuel and high neutron dose material.
Katsuyama, Kozo; Ishimi, Akihiro; Maeda, Koji; Nagamine, Tsuyoshi; Asaka, Takeo
Journal of Nuclear Materials, 401(1-3), p.86 - 90, 2010/06
Times Cited Count:4 Percentile:30.68(Materials Science, Multidisciplinary)The helium releases were investigated in FBR fuel pins irradiated to high burn-up. The released amounts of helium gas increased with the increase of burn-up, but their data were scattered in the region of high burn-up region. This was understood to be caused by the differences of Am contents among fuel pellets, because this nuclide generates Cm which undergoes alpha decay at a short half life.
Katsuyama, Kozo; Maeda, Koji; Nagamine, Tsuyoshi; Furuya, Hirotaka
Nuclear Technology, 169(1), p.73 - 80, 2010/01
Times Cited Count:3 Percentile:24.16(Nuclear Science & Technology)Three-dimensional X-ray CT (computer tomography) images were successfully taken of a fast breeder reactor fuel assembly which had been irradiated to high burn-up. The interior and outside of the fuel assembly can be clearly observed on any cross section from any angle. Using these images, it is possible to analyze the deformation of fuel pins, abnormalities in the fuel assembly, and microstructural change in the fuel pins. 127 central void sizes were tentatively analyzed as a function of linear heat rating. Compared with conventional non-destructive and destructive post irradiation examination (PIEs), this X-ray CT technique has great advantages including the number of PIE data acquisitions in a short time, reduced PIE costs, reduced radioactive waste generation, and physical protection of nuclear materials.
Sakai, Seiji; Naramoto, Hiroshi*; Avramov, P.; Yaita, Tsuyoshi; Lavrentiev, V.; Narumi, Kazumasa; Baba, Yuji; Maeda, Yoshihito
Thin Solid Films, 515(20-21), p.7758 - 7764, 2007/07
Times Cited Count:24 Percentile:68.49(Materials Science, Multidisciplinary)A systematic study is performed for the Co content-dependent structure evolution and electrical properties in the cobalt(Co)-fullerene(C) mixtures in the broad content region. Raman analysis confirms that the mixture has a saturation composition of CoC for the compoundformation. An important role of the covalent Co-C bonds for the characteristic structure and the properties in the Co-C compounds is concluded from the content-dependent peak shifts and the symmetry lowering of C. The Co-dilute mixtures exhibit a semiconductive nature represented bythe activated transport from the shallow mid-gap states. The Co-dense mixtures are characterized by hopping conduction (including variable rangehopping) attributed to the Co clusters/nanoparticles in the compound matrix and by the percolated metallic conduction, depending on the Co content.
Maeda, Toshikatsu; Bamba, Tsunetaka*; Mizuno, Tsuyoshi*; Terakado, Shogo; Kitagawa, Isamu; Numata, Masami
Haikibutsu Gakkai Rombunshi, 17(4), p.271 - 281, 2006/07
no abstracts in English
Ozawa, Tatsuya; Maeda, Toshikatsu; Mizuno, Tsuyoshi; Bamba, Tsunetaka; Nakayama, Shinichi; Hotta, Katsutoshi*
JAEA-Technology 2006-001, 11 Pages, 2006/02
Melting treatment is a candidate solidification technique for nonflammable low-level radioactive wastes including metals, incineration ashes, and glasses. Simulated incineration ashes of a wide range of chemical compositions were molten at 1,600C to produce lab-scale slag form. No visible pores and separated phases were observed in the slag specimens. It was found by optical observation that some precipitates and small voids were uniformly distributed in many of the specimens. The precipitates were identified to be iron oxides by XRD analysis. The present tests indicate that melting treatment is technically capable to produce stable slag from incineration ashes, which is one of representative TRU-cotaminated radioactive wastes.
Maeda, Toshikatsu; Bamba, Tsunetaka*; Hotta, Katsutoshi*; Mizuno, Tsuyoshi*; Ozawa, Tatsuya
Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(4), p.242 - 247, 2005/12
no abstracts in English
Mizuno, Tsuyoshi*; Maeda, Toshikatsu; Bamba, Tsunetaka*
JAERI-Conf 2005-007, p.225 - 229, 2005/08
no abstracts in English
Maeda, Toshikatsu; Bamba, Tsunetaka*; Mizuno, Tsuyoshi*
Haikibutsu Gakkai Rombunshi, 15(1), p.45 - 51, 2004/01
no abstracts in English
Maeda, Seiichiro; Takashita, Hirofumi; Okawa, Tsuyoshi; Higuchi, Masashi*; Abe, Tomoyuki
JNC TN8400 2003-019, 185 Pages, 2003/08
We are studying on an in-core breeding concept as a candidate for a practical FBR fuel cycle system attainable in an early stage on the premise that sodium coolant and mixed oxide fuel should be adopted, since the technical issues with these combination are most advanced and common with the fuel cycle for a LWR-MOX system. An enhancement of fuel volume fraction using thick fuel pins enables the in-core breeding. The fuel material flow can be greatly lessened by minimizing amount of the blanket with the in-core breeding core. The low material flow leads to significant reduction of the fuel cycle cost. We investigated a 3500 MWth large-scale core adjusting several conditions presented in JNC's feasibility study program for a commercialized FBR system in this study. These were shown in this study that a discharged burnup averaged over the core and the blanket could reach approximately 130 GWd/t (core averaged about 150 GWd/t) within the maximum fast neutron fluence about 510/cm, that the small reactivity loss with burnup easily enabled long operation and that stable power distribution during operation significantly improved hydraulic property in this type core. We investigated measures to reduce sodium void reactivity, because core height enlargement to enhance neutron efficiency caused the increase of sodium void reactivity.We also investigated feasibility of a high breeding type core with low burnup considering a variety of FBR introducing scenarios and a trade-off correlation between breeding performance and burnup extension. The performance in this core design at core disruption accidents is not revealed enough. Further investigation should be made in detail to confirm that the in-core breeding concept could be accepted in a safety aspect.
Ura, Tamaki*; Takamasa, Tomoji*; Nishimura, Hajime*; Aoki, Taro*; Ueno, Michio*; Maeda, Toshio*; Nakamura, Masato*; Shimazu, Shunsuke*; Tokunaga, Sango*; Shibata, Yozo*; et al.
JAERI-Tech 2001-049, 154 Pages, 2001/07
JAERI has studied on design and operation of a nuclear powered submersible research vessel, which will navigate under sea in the Arctic Ocean, as a part of the design study of advanced marine reactors. This report describes operation conditions and an operating system of the vessel those were discussed by the specialists of hull design, sound positioning, ship motions and oceanography, etc. The design conditions on ship motions for submersible vessels were surveyed considering regulations in our country, and ship motions were evaluated assuming the observation activities in the Arctic Ocean. A submarine transponder system and an on ice communication buoy system were examined as a positioning and communication system supposing the activity under ice. Procedures to secure safety of nuclear powered submersible research vessel were discussed based on the investigation of accidents. These results were reflected to the concept of the nuclear powered submersible research vessel, and subjects fto be settled in the next step were clarified.
Maeda, Koji; Nagamine, Tsuyoshi; ; Mitsugi, Takeshi; Matsumoto, Shinichiro
Dai-3-Kai Shoshago Shiken Ni Kansuru Nikkan Semina, 0 Pages, 1999/00
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