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Serizawa, Hiroyuki; Matsunaga, Junji*; Haga, Yoshinori; Nakajima, Kunihisa; Akabori, Mitsuo; Tsuru, Tomohito; Kaji, Yoshiyuki; Kashibe, Shinji*; Oishi, Yuji*; Yamanaka, Shinsuke*
Crystal Growth & Design, 13(7), p.2815 - 2823, 2013/07
Times Cited Count：5 Percentile：41.75(Chemistry, Multidisciplinary)Since the shape of the negative crystal closely relates to the morphology of the crystal habits, the formation and the growth mechanism is important subject in a field of the physical science. Whereas, the negative crystal formed in a large single crystal mass has been arousing interest as an expensive jewelry because of its mysterious appearance and rarity. However, it is difficult to control the shape of this polyhedral cavity embedded in a solid medium arbitrary. Here we report the recent discovery on the growth process of the negative crystal. We found that precipitated helium forms the negative crystal in UO
; the shape changes drastically with the condition of the helium precipitation. The transformation mechanism was discussed in this article. Our investigation implies that the shape of the negative crystal can be arbitrary controlled by controlling the precipitation condition.
Arai, Yasuo; Serizawa, Hiroyuki; Nakajima, Kunihisa; Takano, Masahide; Sato, Isamu; Katsuyama, Kozo; Akie, Hiroshi; Suzuki, Motoe; Shirasu, Noriko; Haga, Yoshinori; et al.
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 8 Pages, 2011/12
High amount of He is generated in MA-bearing fuel during irradiation and storage periods compared with that in U or U-Pu fuel. Laboratory scale experiments, post irradiation examinations and modeling study were carried out in order to understand the He behavior in MA-bearing oxide fuel. Diffusion characteristics of He in single-crystal UO were investigated by the Knudsen effusion mass spectrometry. Effects of the He accumulation on lattice and bulk expansion of oxide pellets were examined by use of alpha-decay of 
Cm. Post irradiation examinations of 0.5%Am-MOX fuel irradiated at a fast test reactor JOYO were carried out, concentrating on the He behavior in the fuel pellets. A model describing the He behavior in MA-MOX fuel was constructed based on the principle processes, such as generation, diffusion, equilibrium and release to outer gaseous phase. By use of the model as a subroutine of a conventional fuel behavior analysis code, the He behavior in MA-MOX fuel for fast reactors was simulated.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Masnavi, M.*; Nakajima, Mitsuo*; Sasaki, Akira; Hotta, Eiki*; Horioka, Kazuhiko*
Applied Physics Letters, 87(11), p.111502_1 - 111502_3, 2005/09
Times Cited Count：4 Percentile：17.60(Physics, Applied)no abstracts in English
Masnavi, M.*; Nakajima, Mitsuo*; Sasaki, Akira; Hotta, Eiki*; Horioka, Kazuhiko*
Japanese Journal of Applied Physics, 43(12), p.8285 - 8291, 2004/12
Times Cited Count：5 Percentile：23.64(Physics, Applied)no abstracts in English
Minato, Kazuo; Akabori, Mitsuo; Takano, Masahide; Arai, Yasuo; Nakajima, Kunihisa; Ito, Akinori; Ogawa, Toru
Journal of Nuclear Materials, 320(1-2), p.18 - 24, 2003/09
Times Cited Count：53 Percentile：94.18(Materials Science, Multidisciplinary)In the Japan Atomic Energy Research Institute, the concept of the transmutation of minor actinides (MA: Np, Am and Cm) with accelerator-driven systems is being studied. The MA nitride fuel has been chosen as a candidate because of the possible mutual solubility among the actinide mononitrides and excellent thermal properties besides supporting hard neutron spectrum. MA nitrides of AmN, (Am,Y)N, (Am,Zr)N and (Cm0.4Pu0.6)N were prepared from the oxides by the carbothermic reduction method. The prepared MA nitrides were examined by X-ray diffraction and the contents of impurities of oxygen and carbon were measured. The fabrication conditions for MA nitrides were improved so as to reduce the impurity contents. For an irradiation test of U-free nitride fuels, pellets of (Pu,Zr)N and PuN+TiN were prepared and a He-bonded fuel pin was fabricated. The irradiation test started in May 2002 and will go on for two years in the Japan Materials Testing Reactor.
Minato, Kazuo; Arai, Yasuo; Akabori, Mitsuo; Nakajima, Kunihisa
Proceedings of American Nuclear Society Conference "Nuclear Applications in the New Millennium" (AccApp-ADTTA '01) (CD-ROM), 6 Pages, 2002/00
In the Japan Atomic Energy Research Institute (JAERI), the concept of the transmutation of minor actinides (MA: Np, Am and Cm) with accelerator-driven systems (ADS) is being studied, where MA nitride is adopted as a fuel material of sub-critical core. The nitride fuel has been chosen as a candidate because of the possible mutual solubility among the actinide mononitrides and excellent thermal properties besides supporting hard neutron spectrum. Highly enriched N-15 would have to be used for the nitride fuel in order to prevent the formation of hazardous C-14. By applying pyrochemical process in the treatment of spent fuel, N-15 could be readily recovered and recycled. The present paper describes an overview of the research on the nitride fuel performed in JAERI. Fabrication experiments of actinide nitrides, measurements of vaporization behavior and thermal properties, and irradiation tests of actinide nitrides are summarized.
Hashimoto, Dai; Morimoto, Iwao; Zheng, X.; Maebara, Sunao; Nakajima, Mitsuo*; Horioka, Kazuhiko*; Kono, Toshiyuki*; Shiho, Makoto
JAERI-Research 2000-018, p.66 - 0, 2000/03
JAERI-Research-2000-018.pdf:2.19MB
no abstracts in English
