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Journal Articles

Structures of magnetic excitations in the spin-$$frac{1}{2}$$ kagome-lattice antiferromagnets Cs$$_{2}$$Cu$$_{3}$$SnF$$_{12}$$ and Rb$$_{2}$$Cu$$_{3}$$SnF$$_{12}$$

Saito, 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:7 Percentile:53.46(Materials Science, Multidisciplinary)

Journal Articles

Establishment of a Laboratory for $$gamma$$-ray Spectrometry of Environmental Samples Collected in Fukushima

Saegusa, 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 $$gamma$$-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.

Journal Articles

Survey and countermeasures on radiocesium inflow into a laboratory building 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 $$^{134}$$Cs and $$^{137}$$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.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, 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:193 Percentile:99.41(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 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 $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, 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:10 Percentile:54.53(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 $$p+p$$ 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 $$p+p$$ collisions.

Journal Articles

Innovative powder production and granulation for advanced MOX fuel fabrication

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$$_{3}$$ 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.

Journal Articles

Flowability measurement of coarse particles using vibrating tube method

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:28.79(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$$_{2}$$ and UO$$_{2}$$) particles which are nuclear fuel used for electric power production. Five sizes of non-radioactive model particles, smaller than 850 micrometers, made of ZrO$$_{2}$$ 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.

Journal Articles

Application of microwave heating to MOX fuel production and its contribution to Japanese energy strategy

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$$_{2}$$/UO$$_{2}$$ bulk, 2 kgMOX/batch, advancing toward the mass production target, 5 kgU/h for one batch.

Journal Articles

Development of the simplified MOX pellet fabrication process (short process); Improvement of MOX powder lowability

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.

Journal Articles

Dielectric Properties of Uranium and Plutonium Nitrate Solution and the Oxide Compounds Formed in the De-nitratiin Process by the Microwave Heating Method

Kato, Yoshiyuki; Kurita, Tsutomu; Abe, Tomoyuki

Journal of Nuclear Science and Technology, 41(8), p.857 - 862, 2004/00

 Times Cited Count:13 Percentile:62.66(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$$_{6}$$), however, reacting with fluorine (F2) and plutonium dioxide (PuO$$_{2}$$) 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$$_{4}$$). Suitable conditions should be established for the practical use of this process. One of them is to enhance the stability of PuF$$_{6}$$. 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$$_{6}$$ could be formed stably under a high temperature condition (approx.1000 K) with over supply of figher concentration of F2.

Oral presentation

Development of simplified pelletizing process for MOX fuel; Evaluation test for the structural strengthen of silicon nitride tray at the viewpoint of common use throughout the denitration and granulation process

Kurita, Tsutomu; Kimura, Yuichi; Kato, Yoshiyuki; Yoshimoto, Katsunobu; Suzuki, Masahiro; Uematsu, Keizo*; Tanaka, Satoshi*

no journal, , 

no abstracts in English

Oral presentation

The Examination for realizing the simplified-pelletizing fuel fabrication method production equipment; The Experiment equipment for checking the processing procedure of conversion is installed in Plutonium Conversion Development Facility.

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.

Oral presentation

Development of simplified pellet fuel production technology, 2; Processing technology for de-nitration conversion based on microwave heating

Kato, Yoshiyuki; Kimura, Yuichi; Isomae, Hidemi; Kurita, Tsutomu; Yoshimoto, Katsunobu; Makino, Takayoshi; Suzuki, Masahiro; Kihara, Yoshiyuki

no journal, , 

no abstracts in English

Oral presentation

Development of simplified pellet fuel production technology, 4; Unified technology of de-nitration conversion and granulation

Kurita, Tsutomu; Kato, Yoshiyuki; Yoshimoto, Katsunobu; Ishii, Katsunori; Suzuki, Masahiro; Kihara, Yoshiyuki

no journal, , 

no abstracts in English

Oral presentation

Development of simplified pellet fuel production technology, 3; Mass production technology for De-nitration conversion based on microwave heating

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.

Oral presentation

Effect on heating efficiency by support table height in microwave oven

Tanigawa, Masafumi; Kato, Yoshiyuki; Kurita, Tsutomu; Kusano, Keiichi*; Otaka, Akihiro*; Nakamichi, Hideo*

no journal, , 

no abstracts in English

Oral presentation

Examination that improves solubility of plutonium dioxide in MOX powder

Tanigawa, Masafumi; Kato, Yoshiyuki; Kurita, Tsutomu; Komatsuzaki, Mai*; Otaka, Akihiro*; Nakamichi, Hideo*

no journal, , 

no abstracts in English

Oral presentation

Survey of radiocesium accumulation in the building of Sasakino Analytical Laboratory, JAEA

Kurita, Yoshiyuki; Okazaki, Tsutomu; Maeda, Satoshi; Yoda, Tomoyuki; Saegusa, Jun

no journal, , 

no abstracts in English

Oral presentation

Outline of Sasakino Analytical Laboratory, Fukushima Environmental Safety Center of JAEA

Saegusa, Jun; Yanagisawa, Kayo; Yamaguchi, Toshio; Manabe, Sachi; Yoda, Tomoyuki; Maeda, Satoshi; Utsumi, Azusa; Shibamichi, Masaru; Ejiri, Akira; Kurita, Yoshiyuki; et al.

no journal, , 

no abstracts in English

Oral presentation

Durability examination by the irradiation of a radiation resistance RF tag

Kobayashi, Daisuke; Kato, Yoshiyuki; Kurita, Tsutomu; Iida, Masayoshi*; Teraura, Nobuyuki*; Ito, Kunio*; Sakurai, Koichi*

no journal, , 

no abstracts in English

32 (Records 1-20 displayed on this page)