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Ikeuchi, Hirotomo; Sano, Yuichi; Shibata, Atsuhiro; Koizumi, Tsutomu; Washiya, Tadahiro
Journal of Nuclear Science and Technology, 50(2), p.169 - 180, 2013/02
Times Cited Count：10 Percentile：57.33(Nuclear Science & Technology)An efficient dissolution process was established for future reprocessing in which MOX fuels with high plutonium contents and dissolver solution with high heavy-metal concentrations will be treated. This dissolution process involves short stroke shearing of fuels (10 mm in length). The dissolution kinetics of irradiated mixed-oxide fuels and the effects of the Pu content, heavy-metal concentration and fuel form on the dissolution rate were investigated. Irradiated fuel was decreased with increasing Pu content. Kinetic analysis based on the fragmentation model indicated that the dissolution rate of irradiated fuel was affected not only by the volume ratio of liquid to solid (
ratio), but also by the exposed surface area (
ratio). The penetration rate of nitric acid is expected to be decreased at high heavy-metal concentrations by a reduction in the ratio, but enhanced by shearing the fuel pieces with short strokes and thus enlarging the ratio.
Ikeuchi, Hirotomo; Shibata, Atsuhiro; Sano, Yuichi; Koizumi, Tsutomu
Procedia Chemistry, 7, p.77 - 83, 2012/00
Times Cited Count：21 Percentile：97.37(Chemistry, Analytical)The effects of Pu content were studied on the dissolution rate of irradiated mixed oxide fuel and on the mass of insoluble residue. Kinetic analysis was conducted being based on the surface-reaction model to estimate the dissolution rate of irradiated fuels with Pu contents less than 30% and with burn-up ranging from 40.1 - 63.7 GWD/t. The dissolution rate of irradiated mixed-oxide fuels was found to decrease exponentially with an increase of the Pu content, but those were estimated to be up to 1000 times larger than those of non-irradiated fuels with the same Pu content. The amount of insoluble residue was found to increase with increase of the Pu content, possibly due to the promotion of fission product formation. Up to 1.3% of initial heavy metal was remained as the residue.
Miyaji, Noriko; Kawakami, Yukio; Koizumi, Atsuhiro; Otsuji, Ayako*; Sasaki, Keiichi*
IAEA-CN-184/60 (Internet), 6 Pages, 2010/11
FMF at Oarai Research and Development Center (JNC-2 site) conducts post irradiation examinations (PIE) of fuel assemblies irradiated in Joyo. After the PIEs, the tested material is shipped back to a Joyo spent fuel pond. For the IAEA to apply the integrated safeguards approach (ISA) to the FMF, a new verification system on material transfer between Joyo and the FMF has been established. Gross defect verification of the nuclear material contained in the cask is performed at the time of short notice random interim inspections (RIIs) by measuring the surface neutron dose rate of the cask, filled with water to reduce radiation. As the result of performing a series of preliminary tests, this system could be used for the verification purpose under the ISA. It is clear that application of the system under the ISA provides the transparency of the material shipping and receiving process would be improved.
Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.
JAEA-Research 2010-019, 194 Pages, 2010/08
JAEA-Research-2010-019-01.pdf:48.47MBJAEA-Research-2010-019-02.pdf:19.4MB
This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m
. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.
Tsusaka, Kimikazu; Koizumi, Yu*; Tanimoto, Chikaosa*; Kameyama, Katsuhiro*; Miyajima, Yasuyuki*
Tonneru Kogaku Hokokushu (CD-ROM), 18, p.77 - 84, 2008/11
In TBM tunneling, secondary fragmentation is considered as a phenomenon that rock pieces between a cutter head and face are fragmented through the excavation process. The fragmentation should cause damage and excessive wear to the disc cutters which pass through the dome-shaped part where scrapers scoop up muck. Based on the cutter replacement records in four TBM applications through sedimentary and granitic rocks, the authors investigated the difference in the rolling distance per unit disc diameter loss between the inner cutters and the outer ones. As a result, it was clarified that the cutter life at the outer part were shorter than that at the inner part by more than 20% by the secondary fragmentation.
Al conductor for coils with react-and-wind methodKizu, Kaname; Tsuchiya, Katsuhiko; Shimada, Katsuhiro; Ando, Toshinari*; Hishinuma, Yoshimitsu*; Koizumi, Norikiyo; Matsukawa, Makoto; Miura, Yushi*; Nishimura, Arata*; Okuno, Kiyoshi; et al.
Fusion Engineering and Design, 82(5-14), p.1493 - 1499, 2007/10
Times Cited Count：3 Percentile：24.53(Nuclear Science & Technology)no abstracts in English
Yano, Kimihiko; Shibata, Atsuhiro; Nomura, Kazunori; Koizumi, Tsutomu; Koyama, Tomozo
Journal of Nuclear Science and Technology, 44(3), p.344 - 348, 2007/03
Times Cited Count：10 Percentile：56.21(Nuclear Science & Technology)The crystallization process has been developed as a part of the advanced aqueous process, NEXT (
ew 
traction System for 
RU recovery) for fast reactor (FR) cycle. In this process, a large part of U is separated from dissolver solution by crystallization as UO
(NO) 6HO. The U crystallization test was carried out with real dissolver solution of irradiated FR fuel to investigate the influence of cooling rate on the crystal size and the behavior of fission product (FP) compared with that of Pu(IV). In regard to the influence of the cooling rate, it was obvious that the crystal size was smaller as the cooling rate is faster. Although it was expectable that the decontamination performance was improved by diminishing the specific surface of the crystals, it was suggested that a large crystal produced by crystallization was not always high purity. Concerning the behavior of FPs, Eu behaved similarly to Pu(IV). Cs accompanied with U into the crystals under the condition in this test.
Nakahara, Masaumi; Sano, Yuichi; Koma, Yoshikazu; Kamiya, Masayoshi; Shibata, Atsuhiro; Koizumi, Tsutomu; Koyama, Tomozo
Journal of Nuclear Science and Technology, 44(3), p.373 - 381, 2007/03
Times Cited Count：31 Percentile：86.52(Nuclear Science & Technology)Actinides recovery was attempted by the simplified solvent extraction process using TBP as an extractant for U, Pu and Np co-recovery and the SETFICS process for Am and Cm recovery with a view to decreasing the environmental impact. Uranium, Pu and Np co-recovery was conducted under the condition with high nitric acid concentration in the feed solution or scrubbing solution. High nitric acid concentration in the feed solution availed to the Np oxidation not only in the feed solution, but also at the extraction section. This oxidation reaction permitted the Np extraction with U and Pu. In the SETFICS process, a TRUEX solvent of 0.2M CMPO/1.4M TBP was employed to increase the loading of metals. In place of sodium nitrate, HAN was applied to this experimental flow sheet for "salt-free" concept. This experiment was succeeded in Am and Cm product. On high-loading flow sheet, the flow rate of aqueous effluents and spent solvent was expected to decrease in 47% and 54%, respectively.
Al strand and cable-in-conduit conductorKizu, Kaname; Tsuchiya, Katsuhiko; Shimada, Katsuhiro; Ando, Toshinari*; Hishinuma, Yoshimitsu*; Koizumi, Norikiyo; Matsukawa, Makoto; Miura, Yushi*; Nishimura, Arata*; Okuno, Kiyoshi; et al.
IEEE Transactions on Applied Superconductivity, 16(2), p.872 - 875, 2006/06
Times Cited Count：1 Percentile：11.70(Engineering, Electrical & Electronic)no abstracts in English
Yano, Kimihiko; Shibata, Atsuhiro; Nomura, Kazunori; Koizumi, Tsutomu; Koyama, Tomozo
Recent Advances in Actinide Science, p.644 - 646, 2006/06
U crystallization is effective to minimize solvent extraction process equipment by separating U from dissolver solution of spent fuel. In order to establish crystallization process for FBR MOX fuel, Pu behavior needs to be investigated with mixed U and Pu solution. Pu valence influence on the decontamination factor (DF) of Pu to U in crystal. Pu(IV) was not crystallized with U and DF was about 30. Although Pu(VI) dose not solely crystallized, it was co-crystallized with U and DF of Pu to U in crystal was about 1.3. The effect of Pu(IV) concentration on crystallization yield of U is small. It had a tendency to decrease crystallization yield of U by that Pu(VI) exists, compared with that calculated by solubility of U in U-HNO-HO system.
Yano, Kimihiko; Shibata, Atsuhiro; Nomura, Kazunori; Koizumi, Tsutomu; Koyama, Tomozo
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10
The uranium crystallization process has been developed as part of advanced aqueous reprocessing system. In the process, the great part of uranium is separated from the dissolver solution by crystallization as uranyl nitrate hydrate. The uranium crystallization test was carried out with the dissolver solution of irradiated FBR MOX fuel to investigate the influence of cooling rate on the crystal size and the behavior of fission products compared with that of tetravalent plutonium with the real dissolver solution. In regard to the influence of the cooling rate, it was obvious that the crystal size was smaller as the cooling ratio was faster. However, it was suggested that a large crystal produced by crystallization was always not high purity. Concerning the behavior of fission products, europium behaved similarly to tetravalent plutonium. Cesium accompanied with uranium into the crystals under the condition of this test.
Nakahara, Masaumi; Sano, Yuichi; Koma, Yoshikazu; Kamiya, Masayoshi; Shibata, Atsuhiro; Koizumi, Tsutomu; Koyama, Tomozo
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10
Concerning the advanced aqueous reprocessing system named NEXT process, the behavior of actinide elements was investigated in main two extraction processes of NEXT process, i.e. the simplified PUREX process for U, Pu and Np recovery, and SETFICS process for Am and Cm recovery.
Sano, Yuichi; Shibata, Atsuhiro; Koizumi, Tsutomu; Koyama, Tomozo; Fox, D.*; Carrott, M.*; Taylor, R.*
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10
Based on the U(VI) back-extraction experiments with the miniaturized single stage centrifugal contactor, effects of the total flowrate, the rotor speed and the temperature on the U(VI) mass transfer efficiency were discussed. The relationship between the U(VI) mass transfer efficiency and the residence time suggested that the U(VI) back-extraction system with the centrifugal contactor could be treated as a perfectly stirred continuous reactor. It is considered that the variations of the mass transfer efficiency were caused by the flow pattern change from the laminar flow to the turbulent flow with increasing of the rotor speed in the centrifugal contactor. In the U(VI) back-extraction under the high rotor speed condition, no significant temperature dependence of the apparent overall transform coefficient was observed. In the U(VI) back-extraction under the low rotor speed condition, temperature dependence of the apparent overall transform coefficient seemed to be larger than under the high rotor speed condition, and it suggested a chemical-step contribution in this system. Such a difference of the temperature dependence of the apparent overall transform coefficient between these experiments might be caused by the change of solvent extraction environments in the centrifugal contactor with the variation of the rotor speed.
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
no abstracts in English
Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.
Nuclear Fusion, 44(2), p.329 - 334, 2004/02
Times Cited Count：7 Percentile：22.17(Physics, Fluids & Plasmas)no abstracts in English
Shibata, Atsuhiro; Yano, Kimihiko; Nomura, Kazunori; Koizumi, Tsutomu; Koyama, Tomozo; Miyake, Chie
CD-ROM, P1-66, 3P., 3 Pages, 2004/00
In the NEXT process, the greater part of uranium is separated from dissolver solution by crystallization. It is important to check the behavior of plutonium under the uranium crystallization operating condition in order to prevent plutonium from significantly accompanying uranium. In this study, Pu nitrate solution tests were performed.
Yano, Kimihiko; Shibata, Atsuhiro; Nomura, Kazunori; Koizumi, Tsutomu; Koyama, Tomozo; Miyake, Chie
CD-ROM, P1-66, 4p., 4 Pages, 2004/00
JNC has been developed uranium crystallization process as a component of advanced aqueous reprocessing system, NEXT (New Extraction System for TRU Recovery). In this process the greater part of uranium is separated from dissolver solution by crystallization as uranyl nitrate hexahydrate (UNH). Two types of experiments were carried out to clarify the plutonium behavior under the condition of uranium crystallization from dissolver solution. The results indicated that hexavalent plutonium is co-crystallized with uranium under the condition of uranium crystallization from dissolver solution, although plutonium concentration is lower than its solubility, and tetravalent plutonium is not. Therefore, the adjustment of plutonium valence at tetravalent is needed in order to avoid co-crystallization of plutonium and uranium.
Shibata, Atsuhiro; Nomura, Kazunori; Koizumi, Tsutomu; Koyama, Tomozo
Proceedings of International Conference on Advanced Nuclear Energy and Fuel Cycle Systems (GLOBAL 2003) (CD-ROM), 2251 Pages, 2003/00
JNC has been developed the advanced aqueous reprocessing process. CPF is main hot test field for the reprocessing technologies using FR spent fuel. The hot tests have been restarted since last December. Results of dissolution, crystallization and simplified PUREX process tests were obtained through the first hot tests.
Shibata, Atsuhiro; Nomura, Kazunori; Koizumi, Tsutomu; Koyama, Tomozo
Proceedings of International Conference on Advanced Nuclear Energy and Fuel Cycle Systems (GLOBAL 2003) (CD-ROM), 2251 Pages, 2003/00
None
Kato, Takashi; Tsuji, Hiroshi; Ando, Toshinari; Takahashi, Yoshikazu; Nakajima, Hideo; Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Kawano, Katsumi; Oshikiri, Masayuki*; et al.
Fusion Engineering and Design, 56-57, p.59 - 70, 2001/10
Times Cited Count：18 Percentile：75.27(Nuclear Science & Technology)no abstracts in English
