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CoSiYamauchi, Hiroki; Sari, D. P.*; Yasui, Yukio*; Sakakura, Terutoshi*; Kimura, Hiroyuki*; Nakao, Akiko*; Ohara, Takashi; Honda, Takashi*; Kodama, Katsuaki; Igawa, Naoki; et al.
Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02
Nakada, Akira; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Futagawa, Kazuo; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; et al.
JAEA-Review 2022-078, 164 Pages, 2023/03
JAEA-Review-2022-078.pdf:2.64MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2021 to March 2022. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Sakuma, Kota; Abe, Daichi*; Okada, Shota; Sugaya, Toshikatsu; Nakata, Hisakazu; Sakai, Akihiro
JAEA-Technology 2022-013, 200 Pages, 2022/08
JAEA-Technology-2022-013.pdf:8.41MB
Japan Atomic Energy Agency has aims to carry out near surface disposal of low-level radioactive waste generated from research, medical, and industrial facilities. Therefore, Radioactivity Concentration Corresponding to Dose Criterion for near surface disposal for nuclides in the waste were calculated for the purpose of discussion for radioactivity limits between trench and concrete vault disposal, and key nuclides related to them. This report uses the results of sensitivity analysis and evaluation of the amount of leachate from the disposal facility for concrete vault disposal, and incorporates a new assessment pathway and exposure form that widely assume the conditions of the disposal facility. This trial calculation was carried out and compared with the trial calculation in the previous report, "Evaluation of Radioactivity Concentration Corresponding to Dose Criterion for Near Surface Disposal of Radioactive Waste Generated from Research, Medical, and Industrial Facilities, Volume 1". The results of Radioactivity Concentration Corresponding to Dose Criterion calculated in this report will be used as reference values when selecting key nuclides and for classification into concrete vault disposal when the location has not been decided. After deciding the location of the site, it is necessary to evaluate the dose based on the location conditions.
Ogawa, Rina; Abe, Daichi*; Sugaya, Toshikatsu; Sakuma, Kota; Saito, Tatsuo; Sakai, Akihiro
JAEA-Technology 2022-008, 46 Pages, 2022/05
JAEA-Technology-2022-008.pdf:3.09MB
Japan Atomic Energy Agency (JAEA) has planned to dispose of the Uranium-bearing waste, whose radioactivity concentration is low, in trench disposal facility. In Japan, uranium is a material to impact on human health, therefore Environmental quality standards for water pollution for uranium has been established, and the standard value is 0.002mg/L. Safety of trench disposal facilities will be assessed that radionuclides contained in the radioactive waste are transferred to the biosphere by seepage water and groundwater. Therefore, JAEA considers that not only dose evaluation but also environmental pollution evaluation is needed as a safety assessment. In this report, we examined whether the concentration of uranium leaching from the trench facility in the aquifer can meet the Environmental quality standards. In addition, parameter study under various conditions of disposal facility were done. Based on the results, conditions and issues of future basic design of trench disposal facility were discussed. The uranium concentration in the aquifer was calculated by the one-dimensional dose evaluation code "GSA-GCL2" for the disposal of LLW. As the result, the uranium concentration in the aquifer significantly changed depending on the conditions of design of disposal facility and so on. However, if the shape and arrangement of the trench facility to groundwater flow direction, the distribution coefficient of uranium of the waste layer, the specification of the impermeable layer and their combination are appropriately designed we consider that the uranium concentration of aquifer can made to adapt the environmental quality standard.
Sugaya, Toshikatsu; Abe, Daichi*; Okada, Shota; Nakata, Hisakazu; Sakai, Akihiro
JAEA-Technology 2021-004, 79 Pages, 2021/05
JAEA-Technology-2021-004.pdf:2.86MBJAEA-Technology-2021-004(errata).pdf:0.38MB
JAEA has aims to carry out near surface disposal of low-level radioactive waste generated from research, medical, and industrial facilities. Therefore, radioactivity concentration corresponding to dose criteria of near surface disposal for 220 nuclides in the waste were calculated for the purpose of discussion for radioactivity limits between trench and concrete vault disposal, and key nuclides related to them. We calculated the radioactivity concentrations with consideration of not only the exposure pathways used at calculation of the radioactivity concentration limits of waste packages for near surface disposal by Nuclear Safety Commission but also ones used at the concentration limits for intermediate depth disposal. We also assumed the capacities of the disposal facilities as 44,000 m
for pit disposal and 150,000 m for trench disposal. The radioactivity concentrations calculated in this report is used as the reference values because the disposal site has not been decided yet. Addition to this, the radioactivity concentrations will be revised according to circumstances of development of disposal facilities and so on. In the future, we will decide the radioactivity and radioactive concentration of a waste package described in the license application documents based on the dose assessment taken into consideration the disposal site conditions.
Shiomi, Yuki*; Lustikova, J.*; Watanabe, Shingo*; Hirobe, Daichi*; Takahashi, Saburo*; Saito, Eiji
Nature Physics, 15(1), p.22 - 26, 2018/10
Times Cited Count：17 Percentile：75.63(Physics, Multidisciplinary)Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.
Watanabe, Shingo*; Hirobe, Daichi*; Shiomi, Yuki*; Iguchi, Ryo*; Daimon, Shunsuke*; Kameda, Mai*; Takahashi, Saburo*; Saito, Eiji
Scientific Reports (Internet), 7, p.4576_1 - 4576_6, 2017/07
Times Cited Count：6 Percentile：29.3(Multidisciplinary Sciences)Sugaya, Toshikatsu; Abe, Daichi; Takebe, Shinichi; Nakatani, Takayoshi; Sakai, Akihiro
JAEA-Technology 2016-018, 20 Pages, 2016/09
JAEA-Technology-2016-018.pdf:2.41MB
Decontamination to the pollution which occurred with an accident of a nuclear power plant with Tohoku-district Pacific offing earthquake has been performed. The contaminated soil which occurred in decontamination stores it in the flexible container back, and is the kept situation. To presume concentration of radioactivity of contents from the dose of the flexible container, the 1cm dose equivalent rate per the unit concentration of radioactivity was calculated with QAD-CGGP2R.
Tanabe, Kenji*; Chiba, Daichi*; Oe, Junichiro*; Kasai, Shinya*; Kono, Hideo*; Barnes, S. E.*; Maekawa, Sadamichi; Kobayashi, Kensuke*; Ono, Teruo*
Nature Communications (Internet), 3, p.845_1 - 845_5, 2012/05
Times Cited Count：42 Percentile：82.73(Multidisciplinary Sciences)
P
studied by single-crystal high-pressure neutron diffractionOsakabe, Toyotaka; Kuwahara, Keitaro*; Kawana, Daichi*; Iwasa, Kazuaki*; Kikuchi, Daisuke*; Aoki, Yuji*; Kogi, Masafumi*; Sato, Hideyuki*
Journal of the Physical Society of Japan, 79(3), p.034711_1 - 034711_7, 2010/03
Times Cited Count：18 Percentile：68.64(Physics, Multidisciplinary)Osakabe, Toyotaka; Kakurai, Kazuhisa; Kawana, Daichi*; Kuwahara, Keitaro*
Journal of Magnetism and Magnetic Materials, 310(2, Part3), p.2725 - 2727, 2007/03
no abstracts in English
4PKawana, Daichi*; Kuwahara, Keitaro*; Sato, Masashi*; Takagi, Masatoshi*; Aoki, Yuji*; Kogi, Masafumi*; Sato, Hideyuki*; Sagayama, Hajime*; Osakabe, Toyotaka; Iwasa, Kazuaki*; et al.
Journal of the Physical Society of Japan, 75(11), p.113602_1 - 113602_4, 2006/11
Times Cited Count：11 Percentile：56.28(Physics, Multidisciplinary)We report the first X-ray diffraction experiments of PrFeP under high pressure. We discovered a symmetry lowering from cubic to orthorhombic or lower at the metal-insulator transition temperature, accompanied by a jump in the lattice constant, which indicates a first-order phase transition. The superlattice reflections at q=(1,0,0) observed in the low-pressure nonmagnetic ordered phase are found to disappear in the insulating phase. The temperature dependence of the lattice constant and the absence of the superlattice reflections are well explained by taking into account an antiferromagnetic ordering.
Osakabe, Toyotaka; Kogi, Masafumi*; Kawana, Daichi*; Hannan, A.*; Soyama, Kazuhiko; Kitazawa, Hideaki*
Journal of Magnetism and Magnetic Materials, 272-276, p.2157 - 2158, 2004/05
Times Cited Count：3 Percentile：19.9(Materials Science, Multidisciplinary)no abstracts in English
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phase diagrams of CeSb and CeBiOsakabe, Toyotaka; Hannan, A.*; Kawana, Daichi*; Kogi, Masafumi*; Kitazawa, Hideaki*
Acta Physica Polonica B, 34(2), p.1469 - 1472, 2003/02
no abstracts in English
PKawana, Daichi*; Osakabe, Toyotaka; Kuwahara, Keitaro*; Kikuchi, Daisuke*; Aoki, Yuji*; Kogi, Masafumi*; Sato, Hideyuki*
no journal, ,
no abstracts in English
P, 2Osakabe, Toyotaka; Kawana, Daichi*; Kuwahara, Keitaro*; Iwasa, Kazuaki*; Kikuchi, Daisuke*; Aoki, Yuji*; Kogi, Masafumi*; Sato, Hideyuki*
no journal, ,
no abstracts in English
POsakabe, Toyotaka; Kuwahara, Keitaro*; Kawana, Daichi; Iwasa, Kazuaki*
no journal, ,
Filled skutterudite compound PrFeP shows the non-magnetic phase transition at T
=6.5 K. Recent NMR measurements and theoretical works have predicted that the order parameter of the non-magnetic phase is the 
-type antiferro-quadropole. Under pressure above 2.5 GPa, the non-magnetic phase disappears and the new insulating phase appears, for example, below 9 K at 3.2 GPa. We have performed neutron diffraction experiments under pressure above 3 GPa using the triple-axis spectrometer TAS-1 installed at 2G beam port of JRR-3M in JAEA at Tokai in order to elucidate the order parameter of the pressure-induced insulating phase. We have successfully observed the distinct magnetic Bragg peak at (1,0,0) reciprocal lattice point at 3.2 GPa in the insulating phase. The peak corresponds to an antiferromagnetic long-range ordering of q = (1,0,0). The magnetic moments are 2.0 
/Pr ions, which are align along the [0,0,1] direction. The results indicate that the insulating phase corresponds to the antiferromagnetically orderd phase and the order parameter is switched from the non-magnetic antiferro-quadropole to the antiderro-magnetic dipole by the pressurization of the lattice contraction of 
L/L
0.5.
Takizawa, Daichi*; Takagi, Hitoshi*; Makita, Chikako*; Nakajima, Yuka*; Saito, Etsuko*; Oyama, Tatsuya*; Ichikawa, Takeshi*; Kakizaki, Akira*; Sato, Ken*; Mori, Masatomo*; et al.
no journal, ,
no abstracts in English
Hamasuna, Takeyasu*; Maruo, Kazuhiko*; Iwanade, Akio; Fukuta, Yutaka; Nogami, Daichi; Watanabe, Koichi
no journal, ,
no abstracts in English
