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Francisco, P. C. M.; Matsumura, Daiju; Kikuchi, Ryosuke*; Ishidera, Takamitsu; Tachi, Yukio
Environmental Science & Technology, 56(5), p.3011 - 3020, 2022/03
Times Cited Count：2 Percentile：27.6(Engineering, Environmental)Ota, Katsu; Ushiki, Hiroshi*; Maeda, Shigetaka; Kawahara, Hirotaka; Takamatsu, Misao; Kobayashi, Tetsuhiko; Kikuchi, Yuki; Tobita, Shigeharu; Nagai, Akinori
JAEA-Technology 2015-026, 180 Pages, 2015/11
JAEA-Technology-2015-026.pdf:79.87MB
In the experimental fast reactor Joyo, it was confirmed that the top of the irradiation test sub-assembly of "MARICO-2" (material testing rig with temperature control) had bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). The replacement of the UCS was conducted from May to December 2014. The design and manufacture of UCS was started from 2008, and the installation of UCS was completed successfully in November 21th 2014. The major results gained during the design and manufacture of UCS is as follows.
Yoshioka, Kenichi*; Kikuchi, Tsukasa*; Gunji, Satoshi*; Kumanomido, Hironori*; Mitsuhashi, Ishi*; Umano, Takuya*; Yamaoka, Mitsuaki*; Okajima, Shigeaki; Fukushima, Masahiro; Nagaya, Yasunobu; et al.
Journal of Nuclear Science and Technology, 52(2), p.282 - 293, 2015/02
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)We have developed a void reactivity evaluation method by using modified conversion ratio measurements in a light water reactor (LWR) critical lattice. Assembly-wise void reactivity is evaluated from the "finite neutron multiplication factor", 
, deduced from the modified conversion ratio of each fuel rod. The distributions of modified conversion ratio and on a reduced-moderation LWR lattice, for which the improvement of negative void reactivity is a serious issue, were measured. Measured values were analyzed with a continuous-energy Monte Carlo method. The measurements and analyses agreed within the measurement uncertainty. The developed method is useful for validating the nuclear design methodology concerning void reactivity.
Yoshioka, Kenichi*; Kikuchi, Tsukasa*; Gunji, Satoshi*; Kumanomido, Hironori*; Mitsuhashi, Ishi*; Umano, Takuya*; Yamaoka, Mitsuaki*; Okajima, Shigeaki; Fukushima, Masahiro; Nagaya, Yasunobu; et al.
Journal of Nuclear Science and Technology, 50(6), p.606 - 614, 2013/06
Times Cited Count：1 Percentile：10.61(Nuclear Science & Technology)We have developed an intra-pellet neutron flux and conversion ratio distribution measurement method. A foil activation method with special foils was used for the neutron flux distribution measurement. A 
-ray spectrum analysis method with special collimators was used for the conversion ratio distribution measurement. Using the developed methods, intra-pellet neutron flux distributions and conversion ratio distributions were measured in critical experiments on a reduced-moderation LWR. Measured values were analyzed with a deterministic method and a Monte Carlo method. The neutron flux distribution measurements and analyses agreed within the range of 1% to 2%. The conversion ratio distribution measurements and analyses were consistent with each other. We found that the measurement methods are useful for the validation of neutron behavior in a fuel pellet, which is known as micro reactor physics.
Ikeda, Yasuhisa*; Kawasaki, Takeshi*; Harada, Masayuki*; Nogami, Masanobu*; Kawata, Yoshihisa*; Kim, S.-Y.*; Morita, Yasuji; Chikazawa, Takahiro*; Someya, Hiroshi*; Kikuchi, Toshiaki*
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
An advanced reprocessing system for spent FBR fuels based on two precipitation processes using pyrrolidone derivatives as precipitants has been developed. Experimental results of precipitation behavior of U, Pu and other elements, the heat- and radiation-resistance of precipitants, the thermal decomposition properties of precipitates showed that N-n-butyl-2-pyrrolidone and N-neopentyl-2-pyrrolidone are the appropriate precipitants for the first and second precipitation steps, respectively. From the engineering investigation, We confirmed that the precipitation and the filtration can be done efficiently using the engineering scale equipment and that the fuel pellets are directly prepared by the calcination of the precipitates. On the basis of these results, we evaluated that the proposed system is expected to be one of candidates of the future reprocessing systems for spent FBR fuels.
Hanada, Masaya; Kojima, Atsushi; Tanaka, Yutaka; Inoue, Takashi; Watanabe, Kazuhiro; Taniguchi, Masaki; Kashiwagi, Mieko; Tobari, Hiroyuki; Umeda, Naotaka; Akino, Noboru; et al.
Fusion Engineering and Design, 86(6-8), p.835 - 838, 2011/10
Times Cited Count：13 Percentile：69.55(Nuclear Science & Technology)Neutral beam (NB) injectors for JT-60 Super Advanced (JT-60SA) have been designed and developed. Twelve positive-ion-based and one negative-ion-based NB injectors are allocated to inject 30 MW D
beams in total for 100 s. Each of the positive-ion-based NB injector is designed to inject 1.7 MW for 100s at 85 keV. A part of the power supplies and magnetic shield utilized on JT-60U are upgraded and reused on JT-60SA. To realize the negative-ion-based NB injector for JT-60SA where the injection of 500 keV, 10 MW D beams for 100s is required, R&Ds of the negative ion source have been carried out. High-energy negative ion beams of 490-500 keV have been successfully produced at a beam current of 1-2.8 A through 20% of the total ion extraction area, by improving voltage holding capability of the ion source. This is the first demonstration of a high-current negative ion acceleration of 
1 A to 500 keV. The design of the power supplies and the beamline is also in progress. The procurement of the acceleration power supply starts in 2010.
Hanada, Masaya; Kojima, Atsushi; Inoue, Takashi; Watanabe, Kazuhiro; Taniguchi, Masaki; Kashiwagi, Mieko; Tobari, Hiroyuki; Umeda, Naotaka; Akino, Noboru; Kazawa, Minoru; et al.
AIP Conference Proceedings 1390, p.536 - 544, 2011/09
Times Cited Count：7 Percentile：84.66(Physics, Atomic, Molecular & Chemical)no abstracts in English
Kojima, Atsushi; Hanada, Masaya; Tanaka, Yutaka*; Kawai, Mikito*; Akino, Noboru; Kazawa, Minoru; Komata, Masao; Mogaki, Kazuhiko; Usui, Katsutomi; Sasaki, Shunichi; et al.
Nuclear Fusion, 51(8), p.083049_1 - 083049_8, 2011/08
Times Cited Count：51 Percentile：88.28(Physics, Fluids & Plasmas)Hydrogen negative ion beams of 490 keV, 3 A and 510 keV, 1 A have been successfully produced in the JT-60 negative ion source with three acceleration stages. These successful productions of the high-energy beams at high current have been achieved by overcoming the most critical issue, i.e., a poor voltage holding of the large negative ion sources with the grids of 2 m
for JT-60SA and ITER. To improve voltage holding capability, the breakdown voltages for the large grids was examined for the first time. It was found that a vacuum insulation distance for the large grids was 6-7 times longer than that for the small-area grid (0.02 m). From this result, the gap lengths between the grids were tuned in the JT-60 negative ion source. The modification of the ion source also realized a significant stabilization of voltage holding and a short conditioning time. These results suggest a practical use of the large negative ion sources in JT-60SA and ITER.
Al cable-in-conduit conductorKoizumi, Norikiyo; Matsui, Kunihiro; Hemmi, Tsutomu; Nakajima, Hideo; Takeuchi, Takao*; Banno, Nobuya*; Kikuchi, Akihiro*
Teion Kogaku, 46(8), p.495 - 499, 2011/08
JAEA and NIMS has been collaborating in development of high performance Rapid-Heating-Quenching-Transformation (RHQT) NbAl CIC conductor, aiming at the application of this conductor to DEMO plant. The technical issue of the RHQT NbAl strand in the application to a fusion magnet is stabilization against perturbation. NIMS developed technique to attach copper stabilizer by using electroplating and a sub-scale CIC conductor is developed using this conductor. JAEA performed stability test of the developed CIC conductor to demonstrate efficiency of this copper stabilization technique. The measured stability margin is sufficiently high compared to the one of similar NbTi CIC conductor previously tested by the authors. Then, it can be concluded that the copper stabilizer works efficiently from view point of stability, resulting in solving the remained technical issues in the RHQT CIC conductor. Therefore, we can say that the RHQT NbAl CIC conductor is the most promising candidate for application to magnet in DEMO plant.
Hanada, Masaya; Akino, Noboru; Endo, Yasuei; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Kojima, Atsushi; Mogaki, Kazuhiko; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.208 - 213, 2010/08
A large negative ion source with an ion extraction area of 110 cm 
45 cm has been developed to produce 500 keV, 22 A D
ion beams required for JT-60 Super Advanced. To realize the JT-60SA negative ion source, the JT-60 negative ion source has been modified and tested on the negative-ion-based neutral beam injector on JT-60U. A 500 keV H ion beam has been produced at 3 A without a significant degradation of beam optics. This is the first demonstration of a high energy negative ion acceleration of more than one-ampere to 500 keV in the world. The beam current density of 90 A/m is being increased to meet 130 A/m of the design value for JT-60SA by tuning the operation parameters. A long pulse injection of 30 s has been achieved at a injection D power of 3 MW. The injection energy, defined as the product of the injection time and power, reaches 80 MJ by neutralizing a 340 keV, 27 A D ion beam produced with two negative ion sources.
Hoshi, Harutaka; Kikuchi, Takahiro; Asakura, Toshihide; Morita, Yasuji; Kimura, Takaumi
JAEA-Research 2010-016, 70 Pages, 2010/07
JAEA-Research-2010-016.pdf:2.31MB
We have studied selective separation of Cs and Sr, which are included in high level liquid waste (HLLW) generated from reprocessing of spent nuclear fuel and are major heat generators, by using extractant impregnated adsorbents. Cs adsorbent using calix arane derivatives showed excellent selectivity for Cs. It also showed significant stability against -irradiation. Sr adsorbent using crown ether derivatives also showed high selectivity for Sr from nitric acid solution, except for Ba and Tc. Dynamic capacity decreased ca. 30% after -irradiation. Hot test using genuine HLLW stored in NUCEF was performed for separation of Cs and Sr through columns, respectively. Each Cs and Sr was separated from other typical fission product elements as well as the results obtained in preliminary experiments. Finally, Cs and Sr were separated according to a supposed separation scheme. Although some complexing agents were added in simulate HLLW, no negative effect was found.
Kikuchi, Takahiro; Hoshi, Harutaka; Asakura, Toshihide; Morita, Yasuji; Kimura, Takaumi; Dodbiba, G.*; Fujita, Toyohisa*
JAEA-Research 2010-010, 45 Pages, 2010/07
JAEA-Research-2010-010.pdf:1.31MB
We have investigate that separation of Mo from simulated HLLW using various metal oxides adsorbent. Fe-Pb oxides and manganese oxide showed very high solubility in nitric acid solution. The distribution coefficient of Mo was decreased with increasing nitric acid concentration among tested adsorbents. Adsorption ability of Mo on alumina and cobalt oxide was low in 3M nitric acid. Hematite type iron oxide (Fe adsorbent) and amorphous zirconium oxide had high Mo adsorption ability, in 3M nitric acid. TRU, U and major fission products were not adsorbed on the adsorbent. So, separation of Mo can be achieved by using Fe adsorbent. A part of Mo was adsorbed irreversibly on Fe adsorbent, but reversibly-adsorbed Mo was recovered by oxalic acid, and the adsorbent was able to use repeatedly. Behavior of break-through of Mo is estimated from adsorption isotherm and overall mass transfer coefficient. We found that amount of throughput of Mo increased with decreasing grain size of the adsorbent.
Washiya, Tadahiro; Tayama, Toshimitsu; Nakamura, Kazuhito*; Yano, Kimihiko; Shibata, Atsuhiro; Nomura, Kazunori; Chikazawa, Takahiro*; Nagata, Masanobu*; Kikuchi, Toshiaki*
Journal of Power and Energy Systems (Internet), 4(1), p.191 - 201, 2010/02
Japan Atomic Energy Agency (JAEA) and Mitsubishi Materials Corporation (MMC) are developing the crystallization process for elemental technology of FBR fuel reprocessing. The uranium (U) crystallization process is a key technology for New Extraction System for TRU Recovery (NEXT) process that was evaluated as the most promising process for future FBR reprocessing. We had developed an innovative crystallizer and fabricated an engineering-scale crystallizer and have carried out continuous operation test to investigate the stability of the equipment at steady and non-steady state conditions by using depleted uranium. As for simulating typical failure events in the crystallizer, crystal accumulation and crystal blockage were occurred intentionally, and monitoring method and resume procedure were tried and selected in this work.
Sr solvent impregnated resin against irradiationHoshi, Harutaka; Kikuchi, Takahiro; Morita, Yasuji; Kimura, Takaumi
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 24, 2009/12
Minimization of radioactive waste from reprocessing process of spent nuclear fuel is strongly desired. We develop an advanced technology for separation of heat generating elements (Cs and Sr) from high level waste to optimize radioactive waste by its characteristics. Some novel solvent impregnated resins (SIRs) were prepared and these SIRs indicated promising ability to separate Cs and Sr from other typical fission products dissolved in nitric acid solution. These adsorbents contacting with nitric acid solution were exposed to ray in a vial. After the irradiation, adsorbents were filtrated through a membrane filter. The adsorption capacity was examined by using irradiated adsorbents after drying. It is concluded that both SIRs maintained their high selectivity for Cs and Sr, respectively, after irradiation. Decreasing ratio of adsorption capacity by irradiation can be estimated from these results. It contributes significantly for conceptual design of separation plant.
Shibata, Atsuhiro; Yano, Kimihiko; Kamiya, Masayoshi; Nakamura, Kazuhito; Washiya, Tadahiro; Chikazawa, Takahiro*; Kikuchi, Toshiaki*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 8(3), p.245 - 253, 2009/09
Behavior of Cs in U crystallization process of advanced aqueous reprocessing system was investigated with simulated dissolver solution. Beaker-scale U crystallization experiments were carried out with some simulated dissolver solutions. The results show that possibility of generation of CsNO,Cs
UO (NO)
or Cs-FP complex salt is small. Precipitation experiments of Cs-U(IV) complex salts were also carried out with nitrate solution of U(IV) and Cs. It was found that Cs-U(IV) complex salt was precipitated in higher acidity than 5 mol/dm
. It is suggested that Cs-Pu(IV) precipitates can be generated in the U crystallization process, under specific solution condition.
Yano, Kimihiko; Nakahara, Masaumi; Nakamura, Masahiro; Shibata, Atsuhiro; Nomura, Kazunori; Nakamura, Kazuhito*; Tayama, Toshimitsu; Washiya, Tadahiro; Chikazawa, Takahiro*; Kikuchi, Toshiaki*; et al.
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.143 - 150, 2009/09
Shibata, Atsuhiro; Kaji, Naoya; Nakahara, Masaumi; Yano, Kimihiko; Tayama, Toshimitsu; Nakamura, Kazuhito; Washiya, Tadahiro; Myochin, Munetaka; Chikazawa, Takahiro*; Kikuchi, Toshiaki*
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.151 - 157, 2009/09
As a part of FaCT project, Japan Atomic Energy Agency has been developing a U crystallization process for advanced aqueous reprocessing technology in collaboration with Mitsubishi Materials Corporation. We have carried out experimental studies and obtained fundamental data. Continuous operation tests were also carried out by an engineering-scale crystallizer to confirm productivity of the equipment and to investigate non-steady state conditions. The requirements for the U crystallization process in the FaCT project could be achieved except DF of Cs. More detail investigation is under way to settle the process condition without Pu-Cs double salt formation.
Al strands subjected to an axial-strain for fusion DEMO reactorHemmi, Tsutomu; Koizumi, Norikiyo; Nunoya, Yoshihiko; Okui, Yoshio*; Matsui, Kunihiro; Nabara, Yoshihiro; Isono, Takaaki; Takahashi, Yoshikazu; Okuno, Kiyoshi; Banno, Nobuya*; et al.
IEEE Transactions on Applied Superconductivity, 19(3), p.1540 - 1543, 2009/06
Times Cited Count：16 Percentile：62.03(Engineering, Electrical & Electronic)NbAl cable-in-conduit (CIC) conductors have been developed as one of candidates for the fusion DEMO reactor. The performances of superconducting strands in the CIC conductor are affected by transverse electromagnetic force and thermal strain at reaction heat treatment. In order to accurately design the conductors for the fusion DEMO reactor, the performance evaluation of the NbAl strands, which is processed by a rapid heating, quenching and transformation (RHQT) method, was performed under various temperature, magnetic field and axial-strain conditions. The measured and parameterized results of the NbAl strands are presented.
Shibata, Atsuhiro; Oyama, Koichi; Yano, Kimihiko; Nomura, Kazunori; Koyama, Tomozo; Nakamura, Kazuhito; Kikuchi, Toshiaki*; Homma, Shunji*
Journal of Nuclear Science and Technology, 46(2), p.204 - 209, 2009/02
Times Cited Count：7 Percentile：45.16(Nuclear Science & Technology)A new reprocessing system with 2-stage crystallization process has been developed. In the first stage of the system, U and Pu are recovered from dissolver solution by U-Pu co-crystallization. Laboratory scale experiments were carried out with U and Pu mixed solution and irradiated fuel dissolver solution to obtain fundamental data on U-Pu co-crystallization process. Pu co-crystallized with U, but crystallization yields of Pu were lower than those of U. FPs were separated from U and Pu by co-crystallization, and decontamination factors of Cs and Eu to U in crystal were over 100.
Matsukawa, Makoto; Kikuchi, Mitsuru; Fujii, Tsuneyuki; Fujita, Takaaki; Hayashi, Takao; Higashijima, Satoru; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Ide, Shunsuke; Ishida, Shinichi; et al.
Fusion Engineering and Design, 83(7-9), p.795 - 803, 2008/12
Times Cited Count：17 Percentile：72.65(Nuclear Science & Technology)no abstracts in English
