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Kato, Masashi*; Yoshihara, Kazuki*; Ichimura, Masaya*; Hatayama, Tomoaki*; Oshima, Takeshi
Japanese Journal of Applied Physics, 53(4S), p.04EP09_1 - 04EP09_5, 2014/04
Times Cited Count:6 Percentile:26.85(Physics, Applied)Miyake, Keiko*; Yasuda, Tomonari*; Kato, Masashi*; Ichimura, Masaya*; Hatayama, Tomoaki*; Oshima, Takeshi
Materials Science Forum, 778-780, p.503 - 506, 2014/02
Nakane, Hiroki*; Kato, Masashi*; Ichimura, Masaya*; Oshima, Takeshi
Materials Science Forum, 778-780, p.277 - 280, 2014/02
Sumiya, Shuichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Nakada, Akira; Fujita, Hiroki; Isozaki, Tokuju; Morisawa, Masato; Mizutani, Tomoko; Kokubun, Yuji; et al.
JAEA-Review 2012-015, 166 Pages, 2012/05
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2010 to March 2011. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Plant on Tokyo Electric Power Co. in 2011 March. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data exceeded the normal range of fluctuation by the accidental release was evaluated in the appendices.
Kato, Masashi*; Matsushita, Yoshinori*; Ichimura, Masaya*; Hatayama, Tomoaki*; Oshima, Takeshi
Japanese Journal of Applied Physics, 51(2), p.028006_1 - 028006_2, 2012/02
Times Cited Count:16 Percentile:55.56(Physics, Applied)Excess carrier lifetimes in as-grown and low-energy electron irradiated p-type 4H-SiC epitaxial layers were investigated using the microwave photoconductivity decay method. The carrier lifetime increased with increasing excitation density in the epilayers. This results suggests that the dominant recombination center in the epilayers has larger capture cross section for electrons than capture cross section for holes. The carrier lifetime in the epilayer decreased by the low-energy electron irradiation decreases. The decrease in lifetime in the electron irradiated samples showed recovery after annealing at 1000 C.
Nakamura, Kinya*; Ogata, Takanari*; Kikuchi, Hironobu; Iwai, Takashi; Nakajima, Kunihisa; Kato, Tetsuya*; Arai, Yasuo; Uozumi, Koichi*; Hijikata, Takatoshi*; Koyama, Tadafumi*; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.245 - 256, 2011/12
Sodium-bonded metallic fuel elements were fabricated for the first time in Japan for the irradiation test in the experimental fast test reactor JOYO. U-20Pu-10Zr fuel slugs of 200 mm in length and approximately 5 mm in diameter were fabricated in a small-scale injection casting furnace. Each fuel slug was loaded into the ferritic martenstic stainless steel (PNC-FMS) cladding tube with the sodium thermal bond, thermal insulator and reflector in a helium gas atmosphere glove box. After top-end plug welding to the cladding tube and heat treatment of the welding area, each fuel element was subjected to the sodium bonding process. After the inspection such as element length, gas plenum length and helium-leak tightness, six metallic fuel elements are transported to the JOYO site for the coming irradiation test.
Nakamura, Kinya*; Ogata, Takanari*; Kikuchi, Hironobu; Iwai, Takashi; Nakajima, Kunihisa; Kato, Tetsuya*; Arai, Yasuo; Koyama, Tadafumi*; Itagaki, Wataru; Soga, Tomonori; et al.
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 8 Pages, 2011/12
CRIEPI and JAEA have fabricated sodium-bonded metallic fuel elements for the first time in Japan as a collaborative research, for use in the irradiation test at the experimental fast test reactor Joyo. The irradiation test aims to assess the irradiation behavior of the fuel and the internal wastage of the stainless-steel cladding by rare-earth fission products at a maximum cladding temperature above 873 K. U-20 wt% Pu-10 wt% Zr alloy fuel slugs of 200 mm length were fabricated in an injection-casting furnace using U metal, U-Pu alloy and Zr metal. Two types of fuel slug were fabricated, i.e., 5.05 mm and 4.95 mm in diameter, and loaded into a ferritic-martensitic stainless-steel cladding tubes, respectively. After top-end-plug welding to the cladding tube, each fuel element was subjected to sodium bonding to fill the annular gap between the fuel slug and the cladding with melted sodium. The fabrication results indicated that the characteristics of the fuel elements were within the required specifications.
Furuta, Sadaaki; Sumiya, Shuichi; Watanabe, Hitoshi; Nakano, Masanao; Imaizumi, Kenji; Takeyasu, Masanori; Nakada, Akira; Fujita, Hiroki; Mizutani, Tomoko; Morisawa, Masato; et al.
JAEA-Review 2011-035, 89 Pages, 2011/08
As a correspondence to the accident at the Fukushima Daiichi Nuclear Power Plant, the environmental radiation monitoring was performed at the Nuclear Fuel Cycle Engineering Laboratories, JAEA. This report presented the measurement results of ambient radiation dose rate, radioactivity concentration in the air and radioactivity concentration in fallout and meteorological observation result until May 31, 2011. The ambient radiation dose rate increased, with the peak dose rate of several thousand nGy/h at 7 o'clock in March 15, at 5 o'clock in March 16, and at 4 o'clock in March 21. The variation on the radioactivity concentration in the air and in fallout showed the almost same tendency as that of the dose rate. The concentration ratio of I-131/Cs-137 in the air increased to about 100. The dose was estimated resulting from internal exposure due to inhalation.
Sumiya, Shuichi; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Fujita, Hiroki; Isozaki, Tokuju; Morisawa, Masato; Mizutani, Tomoko; Kokubun, Yuji; et al.
JAEA-Review 2011-004, 161 Pages, 2011/03
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2009 to March 2010. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes.
Matsushita, Yoshinori*; Kato, Masashi*; Ichimura, Masaya*; Hatayama, Tomoaki*; Oshima, Takeshi
Materials Science Forum, 645-648, p.207 - 210, 2010/00
Silicon carbide (SiC) is a promising material for radiation hardness devices. In this study, we evaluated excess carrier decay curves in both as-grown and electron-irradiated p-type 4H-SiC layers by the microwave photoconductivity decay (-PCD) method. The samples used in this study were an Al-doped p-type epitaxial layer grown on a Si-face B doped bulk p-type 4H-SiC. The samples were irradiated with electrons at an energy of 160 keV and at a doses of 110 cm (ele-16) and 110 cm (ele-17). As a results of -PCD measurements, the lifetimes of free carriers for as-grown, ele-16 and ele-17 were estimated to be 0.14 s, 0.07 s and 0.04 s, respectively. This result indicates that defects acting as recombination centers were introduced by the electron irradiation.
Takeishi, Minoru; Sumiya, Shuichi; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki*; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; et al.
JAEA-Review 2009-048, 177 Pages, 2009/12
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2008 to March 2009. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes.
Takeishi, Minoru; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; et al.
JAEA-Review 2008-057, 155 Pages, 2008/11
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter IV; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2007 to March 2008. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.
Maekawa, Yasunari; Kato, Jun*; Katakai, Masashi*; Ishihara, Masaaki*; Enomoto, Kazuyuki; Hagiwara, Tokio*; Ishii, Tatsuhito*; Ito, Kazuo*; Koshikawa, Hiroshi; Yoshida, Masaru
Macromolecular Chemistry and Physics, 209(6), p.625 - 633, 2008/03
Times Cited Count:2 Percentile:7.34(Polymer Science)A polysulfonamide and copolymers consisting of sulfonamides and amides underwent Fries rearrangement and scission, forming amino groups upon EB irradiation. The EB irradiation of these films with a dose of 500 C/cm followed by the color forming reaction provided the color imaging of line/space patterns with resolution of 300 nm.
Takeishi, Minoru; Miyagawa, Naoto; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; Kato, Chiaki; et al.
JAEA-Review 2007-044, 155 Pages, 2008/02
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter 4; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2006 to March 2007. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.
Takeishi, Minoru; Miyagawa, Naoto; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; Kato, Chiaki; et al.
JAEA-Review 2006-031, 155 Pages, 2006/10
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2005 to March 2006. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.
*; *; *; *; *; *; *; *; *; Yonehara, Hidenori*; et al.
EUR-13013-2, p.817 - 828, 1991/00
no abstracts in English
Kato, Masashi*; Fukushima, Keisuke*; Kasuga, Masanobu*; Kito, Kosuke*; Ichimura, Masaya*; Kanechika, Masakazu*; Ishiguro, Osamu*; Kachi, Tetsu*; Oshima, Takeshi
no journal, ,
no abstracts in English
Kato, Masashi*; Matsushita, Yoshinori*; Ichimura, Masaya*; Hatayama, Tomoaki*; Oshima, Takeshi
no journal, ,
no abstracts in English
Nakamura, Kinya*; Ogata, Takanari*; Nakajima, Kunihisa; Kato, Tetsuya*; Iwai, Takashi; Arai, Yasuo; Koyama, Tadafumi*; Itagaki, Wataru; Soga, Tomonori
no journal, ,
Irradiation test of metallic fuel at fast test reactor JOYO is planned. By using techniques of casting, fabrication, analysis and inspection, metallic fuel elements were made for the first time in Japan. In this paper, results of fabrication of U-Pu-Zr alloy fuel slug by emit casting method. Using U metal, U-Pu alloy metal and Zr metal as raw materials, fuel slugs were fabricated by emit casting apparatus in argon gas atmosphere glove box. By inspection, it was confirmed that the specifications were satisfied.
Takahara, Shogo; Kato, Takaaki*; Kimura, Masanori; Iijima, Masashi; Homma, Toshimitsu
no journal, ,
no abstracts in English