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Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Fukasawa, Tomonori*; Fukui, Kunihiro*
Funtai Kogakkai-Shi, 57(9), p.485 - 494, 2020/09
In the spent fuel reprocessing process, a mixed solution of uranyl nitrate and plutonium nitrate is converted into mixed oxide powder by the microwave heating. To evaluate the applicability to the industrial-scale and acquire the characteristics data of the microwave heating denitration of various metal nitrate aqueous solutions based on the knowledge studied in the development of laboratory-scale basic experiments, the microwave heating characteristics and metal oxide powder properties were investigated using cerium nitrate, cobalt nitrate and copper nitrate aqueous solutions. The progress rate of the denitration reaction was depended on the position, and the denitration reaction proceeded faster at the periphery than at the center. The morphologies of the synthesized products were porous and hard dry solid with cerium nitrate aqueous solution, foamed dry solid with cobalt nitrate aqueous solution, and powdery particles with copper nitrate aqueous solution. The denitration ratio and average particle size of the synthesized products increased in the order of the cerium nitrate aqueous solution, the cobalt nitrate aqueous solution, and the copper nitrate aqueous solution. The numerical simulations revealed that the periphery of the bottom surface of the metal nitrate aqueous solution was heated by microwaves. This results consistent with the experimental results in which the denitration reaction started from the periphery of the metal nitrate aqueous solution.
Segawa, Tomoomi; Fukasawa, Tomonori*; Huang, A.-N.*; Yamada, Yoshikazu; Suzuki, Masahiro; Fukui, Kunihiro*
Chemical Engineering Science, 153, p.108 - 116, 2016/10
Times Cited Count：7 Percentile：26.49(Engineering, Chemical)The influence of the heating method and rate on the morphology of CuO powders synthesized from Cu(NO
)
3HO aqueous solutions by denitration was investigated. The median diameter of the obtained powder was found to decrease as the heating rate increased, independent of the heating method. The microwave heating method remarkably reduced the particle size and enhanced the irregularity and disorder of the shape and surface of the particles, which were found to be more widely distributed. In contrast, the microwave hybrid heating method yielded the most spherical particles with the smoothest surface. It was also found that this heating method sharpened the particle size distribution and had higher energy efficiency than the MW method. Numerical simulations also indicated a difference in the energy efficiency between these two methods. The simulations also revealed that the hybrid method could heat the whole reactor more uniformly with a lower microwave output.
Segawa, Tomoomi; Fukasawa, Tomonori*; Yamada, Yoshikazu; Suzuki, Masahiro; Yoshida, Hideto*; Fukui, Kunihiro*
Proceedings of Asian Pacific Confederation of Chemical Engineering 2015 (APCChE 2015), 8 Pages, 2015/09
A mixed solution of uranyl nitrate and plutonium nitrate is converted to MOX raw powder by the microwave heating de-nitration method in nuclear reprocessing. Copper oxide synthesized by heating de-nitration was used as a model for the de-nitration process. The microwave heating method (MW) and infrared heating method (IR) were used, and how they and their heating rate influence the obtained particle morphology and size were investigated. The particles obtained by the MW and IR were sufficiently similar in the surface morphology and the mass median diameter was decreased by the increased heating rate. The mass median diameters by the MW were the heating rate and smaller than those obtained by IR. The particle size distribution of the particle obtained by the MW was broader than that by the IR. The relationship of the temperature distribution and particle size distribution by the MW was discussed by the numerical simulation.
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Arimitsu, Naoki*; Yoshida, Hideto*; Fukui, Kunihiro*
Advanced Powder Technology, 26(3), p.983 - 990, 2015/05
Times Cited Count：8 Percentile：27.86(Engineering, Chemical)Denitration of the aqueous solution of nickel nitrate hexahydrate (Ni(NO)6HO) by a microwave heating method was investigated. Since Ni(NO)6HO aqueous solution cannot be heated to over 300 
C by microwave irradiation owing to the low microwave absorptivity of its intermediate, NiO could not previously be obtained by microwave heating. We propose a novel NiO synthesis method that uses microwave heating without the risk of chemical contamination. A NiO powder reagent was added to the solution as a microwave acceptor. The denitration efficiency to NiO could be improved by an adiabator around the reactor to increase the temperature homogeneity in the reactor. Numerical simulations also reveal that the use of the adiabator results in remarkable changes in the electromagnetic field distribution in the reactor, temperature inhomogeneity decreases.
Fukui, Kunihiro*; Igawa, Yusuke*; Arimitsu, Naoki*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi*; Yamamoto, Tetsuya*; Yoshida, Hideto*
Chemical Engineering Journal, 211-212, p.1 - 8, 2012/11
Times Cited Count：13 Percentile：41.13(Engineering, Environmental)The process for synthesizing metallic oxide powders by the microwave denitration method was investigated using hexahydrated nickel nitrate and trihydrated copper nitrate aqueous solutions, and the electrical field and the temperature distributions in the reactor were numerically simulated. Although CuO powder can be obtained from a trihydrated copper nitrate aqueous solution by the microwave denitration method, a hexahydrated nickel nitrate aqueous solution cannot be heated up to over 270 C by microwave irradiation. It was also found that the reaction routes for microwave heating are the same as those for conventional external heating. This finding indicates that the success of producing oxide particles by microwave denitration depends not only on the microwave absorptivity of the intermediate and the metallic oxide, but also on the temperature difference.
Sn cables for ITER toroidal field coilsIsono, Takaaki; Tsutsumi, Fumiaki; Nunoya, Yoshihiko; Matsui, Kunihiro; Takahashi, Yoshikazu; Nakajima, Hideo; Ishibashi, Tatsuji*; Sato, Go*; Chida, Keiji*; Suzuki, Rikio*; et al.
Teion Kogaku, 47(3), p.147 - 152, 2012/03
no abstracts in English
Sn cable-in-conduit conductorsHemmi, Tsutomu; Harjo, S.; Ito, Takayoshi; Matsui, Kunihiro; Nunoya, Yoshihiko; Koizumi, Norikiyo; Takahashi, Yoshikazu; Nakajima, Hideo; Aizawa, Kazuya; Suzuki, Hiroshi; et al.
IEEE Transactions on Applied Superconductivity, 21(3), p.2028 - 2031, 2011/06
Times Cited Count：10 Percentile：49.97(Engineering, Electrical & Electronic)Residual strain in conductors is caused by the difference in the coefficient of expansion between NbSn strands and the jacket over a temperature range of 5 - 923 K. The superconducting properties of strands vary significantly, depending on the strain. It is important to clarify the residual strain as part of the evaluation of superconducting performance. However, the residual strain of strands in the conductor has not been measured so far because of their complicated configuration and their location in a jacket. The engineering materials diffractometer "Takumi" in J-PARC can measure residual strain with a relative accuracy of around 0.02%, using neutron diffraction. In this study, the Takumi was applied to the measurement of residual strain in strands for the ITER TF conductor. Results indicate that the residual strain of strands in the conductor can be determined, thereby clarifying the mechanism of residual strain and its relationship to superconducting performance.
Hanawa, Yoshio; Tsuboi, Kazuaki; Uchida, Munenori*; Suzuki, Ken*; Takahashi, Kunihiro
JAEA-Technology 2009-078, 18 Pages, 2010/03
JAEA-Technology-2009-078.pdf:11.35MB
Beryllium has been used as the neutron reflector in the Japan Materials Testing Reactor (JMTR). A beryllium frame is arranged in the JMTR core and the frame consists of 3 sections (North, East and West). Each section has 7 stories of the beryllium blocks. Each block is connected by the aluminum joints. The capsule or the beryllium plug is located in the inside of the beryllium frame. The first criticality achieved in 1968 and the frame has been replaced 6 times and now the 7th frame is being manufactured. The replacement is planned to be done in the spring of 2010. The design has been modified to decrease the swelling camber and the lifetime has been improved. The manufacturing procedure is severely controlled to assure the quality. The chemical composition must be specified to minimize the swelling and radiation. The machining procedure is highly controlled because beryllium is very brittle. And the environmental control is also important, because the beryllium is a toxic material.
Suzuki, Kunihiro
Purojekuto Manejimento Gakkai-Shi, 3(6), p.19 - 22, 2001/12
no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Journal of Nuclear Science and Technology, 36(5), p.413 - 423, 1999/05
Times Cited Count：2 Percentile：21.18(Nuclear Science & Technology)no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Nihon Kikai Gakkai Rombunshu, B, 65(633), p.248 - 254, 1999/05
no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Transactions of the American Nuclear Society, 79, p.160 - 161, 1998/00
no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Heat Transfer-Jpn. Res., 26(3), p.159 - 175, 1997/00
no abstracts in English
Hino, Ryutaro; Fujisaki, Katsuo; ; ; Ota, Yukimaru; ; ; Haga, Katsuhiro; ; Mogi, Haruyoshi; et al.
JAERI-Tech 96-037, 45 Pages, 1996/09
no abstracts in English
*; Oyama, Yukio; Sasa, Toshinobu; ; Takizuka, Takakazu; Mizumoto, Motoharu; Watanabe, Noboru*; Mukaiyama, Takehiko; Suzuki, Kunihiro; Tone, Tatsuzo
Application of Accelerators in Research and Industry, 0, p.1115 - 1118, 1996/00
no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
Nihon Kikai Gakkai Rombunshu, B, 62(600), p.3109 - 3117, 1996/00
no abstracts in English
Hino, Ryutaro; Suzuki, Kunihiro; Haga, Katsuhiro; Nekoya, Shinichi; Fukaya, Kiyoshi; Shimizu, Saburo; Onuki, Kaoru; Takada, Shoji; Mogi, Haruyoshi; Sudo, Yukio
JAERI-Review 95-016, 115 Pages, 1995/10
no abstracts in English
Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Sudo, Yukio
JAERI-Research 95-049, 36 Pages, 1995/07
JAERI-Research-95-049.pdf:1.18MB
no abstracts in English
) of the helium engineering demonstration loop (HENDEL)Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Ioka, Ikuo; Sudo, Yukio
JAERI-Research 95-048, 41 Pages, 1995/07
JAERI-Research-95-048.pdf:1.22MB
no abstracts in English
): THANPACST2Takada, Shoji; Suzuki, Kunihiro; Inagaki, Yoshiyuki; Ioka, Ikuo
JAERI-Data/Code 95-005, 203 Pages, 1995/06
JAERI-Data-Code-95-005.pdf:4.7MB
no abstracts in English
