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kagome-lattice antiferromagnets Cs
Cu
SnF
and RbCuSnFSaito, Mutsuki*; Takagishi, Ryunosuke*; Kurita, Nubuyuki*; Watanabe, Masari*; Tanaka, Hidekazu*; Nomura, Ryuji*; Fukumoto, Yoshiyuki*; Ikeuchi, Kazuhiko*; Kajimoto, Ryoichi
Physical Review B, 105(6), p.064424_1 - 064424_15, 2022/02
Times Cited Count：6 Percentile：73.14(Materials Science, Multidisciplinary)
-ray Spectrometry of Environmental Samples Collected in FukushimaSaegusa, Jun; Yoda, Tomoyuki; Maeda, Satoshi; Okazaki, Tsutomu; Otani, Shuichi; Yamaguchi, Toshio; Kurita, Yoshiyuki; Hasumi, Atsushi; Yonezawa, Chushiro*; Takeishi, Minoru
Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1078 - 1085, 2017/11
After the nuclear accident at the Fukushima Daiichi Nuclear Power Plant in March 2011, the Japan Atomic Energy Agency has newly set up a laboratory for radioactivity analysis in Fukushima. At the laboratory, radioactivity concentrations of environmental samples such as soil, water, dust filter, plant, etc., approximately 1,000 samples in a month, are measured with high-resolution -ray spectrometry systems. The systems employ n-type HPGe detectors from Ortec. Since September 2012, characterization and upgrade of the systems have been performed aimed at enhancing reliability of analysis and convenience of customers. Resolving both systematic and technical issues, the laboratory has been accredited the ISO/IEC 17025 standard as a testing laboratory for radioactivity analysis.
Kurita, Yoshiyuki; Saegusa, Jun; Maeda, Satoshi
Nihon Hoshasen Anzen Kanri Gakkai-Shi, 15(2), p.180 - 185, 2016/11
In 2012, JAEA has established a laboratory in Fukushima-city to implement radioactivity analysis of environmental samples. Key nuclides measured in this laboratory are 
Cs and 
Cs (radiocesium). For the purpose, situation of radiocesium inflow into the laboratory building and its effects were investigated based on high-resolution gamma-spectrometry with germanium detectors. As a result, the surface density of radiocesium in the laboratory was found to be far below the minimum detectable activities of survey instruments routinely used for radiation control purposes.
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.44(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：8 Percentile：49.7(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
Kurita, Tsutomu; Kato, Yoshiyuki; Yoshimoto, Katsunobu; Suzuki, Masahiro; Kihara, Yoshiyuki; Fujii, Kanichi
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.94 - 102, 2009/09
With regard to advanced MOX fuel fabrication, a new concept in which one vessel especially designed to meet microwave de-nitration is utilized also for crushing and for granulation, without organic lubricant nor powder transfer across the processes, was introduced for innovative MOX powder production. In order to realize this concept, two attempts were made: A specially designed three blade impeller coupled with auxiliary blade. A uniquely shaped mixing blade coupled with an auxiliary blade having auto-orbital hybrid rotation. The mixing blade promotes the growth of particles, whereas the auxiliary blade suppresses the overgrowth by chopping larger particles. These granulators use a little water as binder. As a result, major diameter of granule 400-1000 micron and flow-ability 82-85 was obtained with fine WO model powder. Therefore, a prospect to satisfy both desirable powder properties and simplified nuclear material production was opened, as well as improvement of working efficiency and cut down on costs.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Yasuda, Masatoshi*; Matsusaka, Shuji*
Journal of Chemical Engineering of Japan, 42(5), p.319 - 324, 2009/05
Times Cited Count：7 Percentile：29.75(Engineering, Chemical)The flowability of coarse particles has been experimentally investigated using the vibrating tube method, to evaluate the applicability of this method to MOX (mixed oxide of PuO and UO) particles which are nuclear fuel used for electric power production. Five sizes of non-radioactive model particles, smaller than 850 micrometers, made of ZrO were prepared, and the experiments were carried out using vibrating tubes with an outlet diameter from 2 to 4 mm. The outlet diameter significantly affected the flowability measurements. When using the tube with a 4-mm-outlet diameter, the flowability of all the model particles was successfully measured. The inclination angle of the tube, also, affected the flowability measurements. From the advantages of high sensitivity, short measurement time, simple structure, and easy operation, the vibrating tube method is expected to be applied to the remote flowability measurement of the MOX particles.
Suzuki, Masahiro; Ishii, Katsunori; Yamamoto, Takuma; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Fujii, Kanichi
Proceedings of Global Congress on Microwave Energy Applications (GCMEA 2008/MAJIC 1st), p.501 - 504, 2008/08
The natural resources, oil and uranium, would dry up around the midway of this century. FBR cycle most probably rescues this difficult situation. Mass production of MOX fuel for FBR, therefore, is the supreme subject to Japanese energy strategy. For this subject, we are attacking with Microwave heating technology. Up to present, we have succeeded to produce excellent PuO/UO bulk, 2 kgMOX/batch, advancing toward the mass production target, 5 kgU/h for one batch.
Makino, Takayoshi; Okita, Takatoshi; Kato, Yoshiyuki; Kurita, Tsutomu; Takahashi, Yoshiharu; Aono, Shigenori
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10
A simplified MOX pellet fabrication process, called short process, has been developed to drastically reduce fuel fabrication cost.The MH powder has characteristic of fine particle and low flowability. It is difficult to pelletize the MH powder directly without granulation into smaller size FR pellet compared with LWR fuel. Therefore, small-scale hot tests to improve the flowability of the MH powder has been carried out using two kinds of methods, and quality of the pellet was evaluated.
Kato, Yoshiyuki; Kurita, Tsutomu; Abe, Tomoyuki
Journal of Nuclear Science and Technology, 41(8), p.857 - 862, 2004/00
Times Cited Count：12 Percentile：61.53(Nuclear Science & Technology)The application of the fluoride volatility process in the reprocessing of fuel from the fast breeder reactor is regarded as one of the economical methods. Plutonium hexafluoride (PuF
), however, reacting with fluorine (F2) and plutonium dioxide (PuO) as the raw material, is in an unstable condition and tends to remain as a solid compound in the process after decomposing into plutonium tetrafluoride (PuF
). Suitable conditions should be established for the practical use of this process. One of them is to enhance the stability of PuF. The behaviour of plutonium fluorination and relevant chemical reactions were investigated by referring to sundry literature and by thermodynamic calculation. It was then compared with recent data from laboratory scale experiments for this paper. Results from the theoretical analysis agreed with experimental observation that PuF could be formed stably under a high temperature condition (approx.1000 K) with over supply of figher concentration of F2.
Kurita, Tsutomu; Kato, Yoshiyuki; Mukai, Yasunobu; Makino, Takayoshi; Kimura, Yuichi*; Nemoto, Ryo*
no journal, ,
no abstracts in English
Kato, Yoshiyuki; Mukai, Yasunobu; Kurita, Tsutomu; Yoshimoto, Katsunobu
no journal, ,
It aims at realizing a light water reactor cycle, the safety more than equivalent, and economical efficiency in a utilization plant in FBR cycle utilization research and development (FaCT project), and the simplification pellet method was selected by the main concept with the fuel cycle institution. In order to check the enactment nature of adjustment equipment among the simplification pellet methods in the end of precursor powder, it changes to test equipment of an old beaker scale, and small-scale MOX test equipment is fixed.
Kato, Yoshiyuki; Mukai, Yasunobu; Kurita, Tsutomu; Yoshimoto, Katsunobu
no journal, ,
Nuclear energy is indispensable to secure long-term energy supply and to prevent global warning by taking advantage of very small CO discharge. Current power reactor will be replaced by next generation Fast Breeder Reactor (FBR) and its fuel cycle step by step because FBR can utilize limited uranium resource to the utmost and minimize high level radioactive wastes. To achieve the target, Fast Reactor Cycle Technology Development (FaCT) project is being promoted in Japan and a simplified MOX fuel fabrication technology where microwave heating denitration is the core of manufacturing is adopted. Adjustment of plutonium/uranium mixed ratio is done just before denitration and treatment to improve powder fluidity is done continuously after the denitration, thus fuel fabrication process becomes short and economical efficiently. Current research has been examined using test equipment of a beaker scale, and it will be replaced to test equipment with capacity of 1 kgMOX/batch where practicability of the technology will be confirmed. The outline of design and schedule of the technology is introduced.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Matsusaka, Shuji*; Yasuda, Masatoshi*; Suna, Takayuki*; Kurita, Tsutomu; Kato, Yoshiyuki
no journal, ,
JAEA is developing simplified pelletizing MOX fuel fabrication process for fast breeder reactor. The final product of de-nitration, conversion and granulation process, are MOX fuel particles, of which diameter is hundres micrometer. These particles should have high flowability for easy handling in next process. The powder flowability is now evaluated by Carr's flowability index. In this oral presentation, the feasibility of powder flowability evaluation using vibrationg capillary method is investigated, employing ZrO particles of shich parameters are diameter and particle shape (shapes are varied by gronding particle edge). Screening small particles under about 100 micrometer contribute best the improvement of powder flowability, screening small particle under 50 micrometer in the second, and rounding particle shape in the third.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Kurita, Tsutomu; Kato, Yoshiyuki; Yasuda, Masatoshi*; Matsusaka, Shuji*; Yoshimoto, Katsunobu
no journal, ,
Particle flowability test using a vibrating tube with a tapered end was carried out to evaluate the applicability of this method to the analysis of MOX particles for nuclear fuel pellet fabrication. In this experiment, zirconia particles were used as model particles, which are less than 850 micrometers in diameter. The sample particles were prepared by mixing the particles with different sizes. The experimental results showed that stable fowability evaluation is possible for particles larger than 45 micrometers and less than 850 micrometres, adjusting outlet diameter of tube and inclination angle of tube.
Kato, Yoshiyuki; Kurita, Tsutomu; Matsumoto, Masaki; Suzuki, Masahiro; Ishii, Katsunori; Yamamoto, Takuma; Kihara, Yoshiyuki; Yoshimoto, Katsunobu; Fujii, Kanichi
no journal, ,
An earlier accomplishment of FBR(fast breeder reactor) fuel cycle is the supreme subject from the point of view on the protection of environment by suppressing the green house effect as well as saving the oil. Microwave heating (MH) is employed as the MOX (mixed oxides U-Pu) production process in the main stream of FBR cycle. Thus, we are the optimization of MH method. We will describe the practical work of MOX fuel production which recycles the consumed nuclear fuel containing both U and Pu. The MH is employed to solidify the mixed solution by evaporating nitric acid and water. We call this processing de-nitration. The physical, mechanical, and chemical characteristics of the products are analyzed, being thereby discussed the contribution of the MH technology to the MOX fuel production. And, optimization of MH is discussed from the view point of design of MH oven, regulation of MH power, and combination with several auxiliary heating sources.
Kato, Yoshiyuki; Kimura, Yuichi; Isomae, Hidemi; Kurita, Tsutomu; Yoshimoto, Katsunobu; Makino, Takayoshi; Suzuki, Masahiro; Kihara, Yoshiyuki
no journal, ,
no abstracts in English
Kurita, Tsutomu; Kato, Yoshiyuki; Yoshimoto, Katsunobu; Ishii, Katsunori; Suzuki, Masahiro; Kihara, Yoshiyuki
no journal, ,
no abstracts in English
Ishii, Katsunori; Yamamoto, Takuma; Suzuki, Masahiro; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Yoshimura, Tadahiro*
no journal, ,
To confirm the prospect of the simplified pellet production technology, JAEA is developing mass production technology for de-nitration conversion based on microwave heating. Base on the experimental result, the suitable processes for the mass production, are selected.
Suzuki, Masahiro; Ishii, Katsunori; Kihara, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Okita, Takatoshi; Kashimura, Motoaki; Kato, Masato; Namekawa, Takashi; Fujii, Kanichi
no journal, ,
In FaCT project, we have set major six technologies for success of simplified pellet fuel fabrication. Our schedule on the technical fundamental technology should be completed by 2010, being transferred to the development of a technology for tele-command operation of mass production and facility maintenance until 2015. In this time, we will report current states of FaCT project as well as future plan.
