Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*; Matsuura, Yasutaka*; Hayashi, Keisuke*
Proceedings of International Conference on Nuclear Decommissioning; Addressing the Past and Ensuring the Future 2023 (Internet), 4 Pages, 2025/00
The development of technology to visualize the distribution of radioactive substances at the decommissioning site of the Fukushima Daiichi Nuclear Power Station (FDNPS) is important for reducing worker exposure and developing a detailed work plan. Sato, one of the authors, developed an integrated Radiation Imaging System (iRIS) that combines a Simultaneous Localization and Mapping (SLAM) device, a Compton camera (a type of gamma-ray imager), and a survey meter, and have successfully produced a 3-D map of the working environment inside the FDNPS that visualizes the location of radioactive hot spots and the distribution of air dose rates. In addition, the authors are developing a system that enables users to experience the radiation environment of the FDNPS in virtual reality (VR) using the 3-D map visualizing such radiation information as input data. This VR system can use a commercially available portable VR head-mounted display, which not only displays the location of the radiation source in a virtual space, but also has the ability to calculate the exposure dose according to the working time. The development status of this VR system, which is expected to be effective in educating inexperienced workers and planning work, will be presented at the conference.
Sano, Yuichi; Sakamoto, Atsushi; Miyazaki, Yasunori; Watanabe, So; Morita, Keisuke; Emori, Tatsuya; Ban, Yasutoshi; Arai, Tsuyoshi*; Nakatani, Kiyoharu*; Matsuura, Haruaki*; et al.
Proceedings of International Conference on Nuclear Fuel Cycle; Sustainable Energy Beyond the Pandemic (GLOBAL 2022) (Internet), 4 Pages, 2022/07
We developed a hybrid MA(III) recovery process combining MA(III)+Ln(III) co-recovery flowsheet by solvent extraction with TBP and MA(III)/Ln(III) separation flowsheet by simulated moving bed chromatography using HONTA impregnated adsorbents with large particle size porous silica support.
Fe
O
Cl with tunable direction in three dimensionsAbe, Nobuyuki*; Shiozawa, Shunsuke*; Matsuura, Keisuke*; Sagayama, Hajime*; Nakao, Akiko*; Ohara, Takashi; Tokunaga, Yusuke*; Arima, Takahisa*
Physical Review B, 101(18), p.180407_1 - 180407_5, 2020/05
Times Cited Count：4 Percentile：18.85(Materials Science, Multidisciplinary)Goto, Minoru; Okumura, Keisuke; Nakagawa, Shigeaki; Inaba, Yoshitomo; Matsuura, Hideaki*; Nakaya, Hiroyuki*; Katayama, Kazunari*
Fusion Engineering and Design, 136(Part A), p.357 - 361, 2018/11
Times Cited Count：10 Percentile：62.83(Nuclear Science & Technology)A High Temperature Gas-cooled Reactor (HTGR) is proposed as a tritium production device, which has the potential to produce a large amount of tritium using 
Li(n,
)T reaction. In the HTGR design, generally, boron is loaded into the core as a burnable poison to suppress excess reactivity. In this study, lithium is loaded into the HTGR core instead of boron and is used as a burnable poison aiming to produce thermal energy and tritium simultaneously. The nuclear characteristics and the fuel temperature were calculated to confirm the feasibility of the lithium-loaded HTGR. It was shown that the calculation results satisfied the design requirements and hence the feasibility was confirmed for the lithium-loaded HTGR, which produce thermal energy and tritium.
O
Matsuura, Keisuke*; Sagayama, Hajime*; Uehara, Amane*; Nii, Yoichi*; Kajimoto, Ryoichi; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Ji, S.*; Abe, Nobuyuki*; Arima, Takahisa*
Physica B; Condensed Matter, 536, p.372 - 376, 2018/05
Times Cited Count：2 Percentile：8.68(Physics, Condensed Matter)O
Matsuura, Keisuke*; Sagayama, Hajime*; Uehara, Amane*; Nii, Yoichi*; Kajimoto, Ryoichi; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Ji, S.*; Abe, Nobuyuki*; Arima, Takahisa*
Physical Review Letters, 119(1), p.017201_1 - 017201_6, 2017/07
Times Cited Count：16 Percentile：67.28(Physics, Multidisciplinary)Numakura, Masahiko*; Sato, Nobuaki*; Bessada, C.*; Okamoto, Yoshihiro; Akatsuka, Hiroshi*; Nezu, Atsushi*; Shimohara, Yasuaki*; Tajima, Keisuke*; Kawano, Hirokazu*; Nakahagi, Takeshi*; et al.
Progress in Nuclear Energy, 53(7), p.994 - 998, 2011/11
Times Cited Count：13 Percentile：66.84(Nuclear Science & Technology)X-ray absorption fine structure (XAFS) measurements on thorium fluoride in molten lithium-calcium fluoride mixtures and molecular dynamics (MD) simulation of zirconium and yttrium fluoride in molten lithium-calcium fluoride mixtures have been carried out. In the molten state, coordination number of thorium and inter ionic distances between thorium and fluorine in the first neighbor are nearly constant in all mixtures. However the fluctuation factors (Debye-Waller factor and C
cumulant) increase until 
CaF = 0.17 and decrease by addition of excess CaF. It means that the local structure around Th
is disordered until CaF=0.17 and stabilized over CaF = 0.17. The variation of fluctuation factors is related to the number density of F
in ThF mixtures and the stability of local structure around Th increases with decreasing the number density of F in ThF mixtures. This tendency is common to those in the ZrF and YF mixtures.
Matsuura, Hideharu*; Izawa, Keisuke*; Minohara, Nobumasa*; Oshima, Takeshi
Japanese Journal of Applied Physics, 47(7), p.5355 - 5357, 2008/07
Times Cited Count：2 Percentile：9.46(Physics, Applied)The reduction in hole concentration (
) in Al-implanted -type 6H-SiC due to 1 MeV electron irradiation was studied. By analysis of , the acceptor density (
), its ionizing energy (
) and nature of the acceptor are determined. As a result, the acceptor observed in this study is assigned to an Al acceptor. is independent of irradiation fluence (
), in spite that is strongly dependent on . We derived an analytical expression for the fluence dependence of and we estimated the removal coefficient (i.e., removal cross-section) of to be 6.4
10
cm
for 1 MeV electron irradiation. The reduction in p due to electron irradiation is found to be mainly due to the decrease in , not to the increase in the density of defects with deep-level, because the decrease in is much larger than the increment in the density of deep-level defects.
Iwamura, Takamichi; Okubo, Tsutomu; Akie, Hiroshi; Kugo, Teruhiko; Yonomoto, Taisuke; Kureta, Masatoshi; Ishikawa, Nobuyuki; Nagaya, Yasunobu; Araya, Fumimasa; Okajima, Shigeaki; et al.
JAERI-Research 2004-008, 383 Pages, 2004/06
JAERI-Research-2004-008.pdf:21.49MB
The present report contains the achievement of "Research and Development on Reduced-Moderation Light Water Reactor with Passive Safety Features", which was performed by Japan Atomic Energy Research Institute (JAERI), Hitachi Ltd., Japan Atomic Power Company and Tokyo Institute of Technology in FY2000-2002 as the innovative and viable nuclear energy technology (IVNET) development project operated by the Institute of Applied Energy (IAE). In the present project, the reduced-moderation water reactor (RMWR) has been developed to ensure sustainable energy supply and to solve the recent problems of nuclear power and nuclear fuel cycle, such as economical competitiveness, effective use of plutonium and reduction of spent fuel storage. The RMWR can attain the favorable characteristics such as high burnup, long operation cycle, multiple recycling of plutonium (Pu) and effective utilization of uranium resources based on accumulated LWR technologies.
Yanagisawa, Hideki*; Izawa, Keisuke*; Matsuura, Hideharu*; Oshima, Takeshi
no journal, ,
no abstracts in English
Sugiura, Yuki; Nonaka, Mai; Sugiyama, Yoshimi*; Hayashi, Keisuke*; Matsuura, Yasutaka*; Amano, Yuki; Ishidera, Takamitsu
no journal, ,
Crystalline rocks are being considered as potential host rocks for the geological disposal of high-level radioactive waste in several countries. The Kd values of radionuclides for crystalline rocks vary greatly and are complicated by multiple factors, such as solution conditions (e.g., pH, ionic strength), solid phase conditions (e.g., CEC, mineralogy), and the chemical properties of the radionuclides, making it difficult to predict Kd values under certain conditions. Recently, there has been an increase in the application of machine learning as a regression prediction method. In this study, we investigated the possibility of predicting Kd values of Cs for crystalline rocks using machine learning (XGboost) with the JAEA-SDB, which contains a large number of Kd values together with experimental conditions. As a result, we were able to predict the Kd values of Cs for crystalline rocks under a wide range of conditions, and to quantitatively evaluate the impact of each factor on Kd values by SHAP values.
Goto, Minoru; Okumura, Keisuke; Nakagawa, Shigeaki; Inaba, Yoshitomo; Matsuura, Hideaki*; Nakaya, Hiroyuki*; Katayama, Kazunari*
no journal, ,
A feasibility study of a High Temperature Gas-cooled Reactor (HTGR) for tritium production using Li(n,)T reaction for fusion reactors has been conducted. In this study, the burn-up chain was modified to treat Li(n,)T reaction directory in neutronics calculations, and then the feasibility study was performed from the view point of nuclear and thermal characteristics using SRAC code system, which has experience in neutronics analysis of HTGRs.
Sugiura, Yuki; Nonaka, Mai; Sugiyama, Yoshimi*; Hayashi, Keisuke*; Matsuura, Yasutaka*; Amano, Yuki; Ishidera, Takamitsu
no journal, ,
no abstracts in English
Goto, Minoru; Okumura, Keisuke; Nakagawa, Shigeaki; Matsuura, Hideaki*; Nakaya, Hiroyuki*; Katayama, Kazunari*
no journal, ,
A feasibility study of a High Temperature Gas-cooled Reactor (HTGR) for tritium production using Li(n,)T reaction for fusion reactors has been conducted. In this study, the burn-up chain was modified to treat Li(n,a)T reaction directory in neutronics calculations, and then the feasibility study was performed from the view point of nuclear characteristics using SRAC code system, which has experience in neutronics analysis of HTGRs.
Oyama, Kenji*; Yokoo, Tetsuya*; Ito, Shinichi*; Suzuki, Junichi*; Iwasa, Kazuaki*; Sato, Taku*; Kira, Hiroshi*; Sakaguchi, Yoshifumi*; Ino, Takashi*; Oku, Takayuki; et al.
no journal, ,
