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Yamashita, Kiyoto; Yokoyama, Aya*; Takagai, Yoshitaka*; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke
JAEA-Technology 2022-020, 106 Pages, 2022/10
JAEA-Technology-2022-020.pdf:4.77MB
Radioactive solid wastes generated by Fukushima Daiichi Nuclear Power Station disaster may contain high levels of salt from the tsunami and seawater deliberately released into the area. It is assumed that polyvinyl chloride (PVC) products may be used for decommissioning work and for containment of radioactive wastes in the future. Among the method of handling them, incineration is one method that needs to be investigated as it is good method for reduction and stabilization of wastes. But in order to dispose of Trans-Uranic (TRU) solid waste containing chlorides, it is necessary to select the structure and materials of the facility based on the information such as the movement of nuclides and chlorides in the waste gas treating system and the corrosion of equipment due to chlorides. Therefore, we decided to get various data necessary to design a study of the incineration facilities. And we decided to examine the transfer behavior of chlorides to the waste gas treatment system, the corrosion-resistance of materials in the incineration facilities, and the distribution survey of plutonium in them obtained using the Plutonium-contaminated Waste Treatment Facility (PWTF), Nuclear Fuel Cycle Engineering Laboratories, which is a unique incinerating facility in Japan. This report describes the transfer behavior of chlorides in the waste gas treatment system, the evaluation of corrosion-resistance materials and the distribution survey of plutonium in the incineration facilities obtained by these tests using the Plutonium-contaminated Waste Treatment Facility, Nuclear Fuel Cycle Engineering Laboratories.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：23 Percentile：96.73(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Fujita, Satoshi*; Kuma, Kenshi*; Ishikawa, Satoko*; Nishimura, Shotaro*; Nakayama, Yuta*; Ushizaka, Satomi*; Isoda, Yutaka*; Otosaka, Shigeyoshi; Aramaki, Takafumi*
Journal of Geophysical Research, 115(C12), p.C12001_1 - C12001_12, 2010/12
Times Cited Count：14 Percentile：38.27(Oceanography)Vertical distributions of dissolved iron (D-Fe, less than 0.22 micrometer fraction), total iron (T-Fe, unfiltered), and chemical and biological components (e.g., nutrients) in seawater were determined at seven stations in the Japan Sea to understand the mechanisms that control iron behavior. Distributions of the D-Fe were characterized by surface depletion, mid-depth maxima, then slight decrease with depth in deep water and uniform concentration in bottom water because of biological uptake in the surface water and release from microbial decomposition of sinking organic matter in mid-depth water. The T-Fe concentrations in the deep-water column were variable with different T-Fe levels among stations and depths. We found a significant relationship of the exponential increase in the T-Fe concentrations with decreasing water transmittance, resulting from the iron supply into the deep and bottom waters due to the lateral transport of resuspended sediment from the continental slope.
Sekimoto, Hitoshi*; Kawachi, Naoki; Honda, Shuzo*; Yamaguchi, Yoshie*; Kato, Shota*; Yoneyama, Kaori*; Fujimaki, Shu; Suzui, Nobuo; Ishii, Satomi; Watanabe, Satoshi; et al.
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 124, 2008/03
no abstracts in English
Sekimoto, Hitoshi; Honda, Shuzo*; Kato, Shota*; Ochiai, Yukiko*; Yoneyama, Kaori*; Yoneyama, Koichi*; Takeuchi, Yasutomo*; Kawachi, Naoki; Fujimaki, Shu; Suzui, Nobuo; et al.
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 125, 2007/02
Maki, Shota
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Maki, Shota; Shibata, Yuichi; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke; Osawa, Takayasu
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Maki, Shota; Fukui, Masahiro; Iemura, Keisuke; Osawa, Takayasu
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waste drumsMaki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke; Osawa, Takayasu
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Yokosuka, Kazuhiro; Maki, Shota; Fukui, Masahiro; Shibata, Yuichi; Iemura, Keisuke; Osawa, Takayasu
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Yokosuka, Kazuhiro; Maki, Shota; Fukui, Masahiro; Iemura, Keisuke; Osawa, Takayasu
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Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke; Osawa, Takayasu
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Fukui, Masahiro; Yokosuka, Kazuhiro; Maki, Shota; Shibata, Yuichi; Shigihara, Yuta; Ouchi, Takahiro; Minouchi, Hiroyuki; Iemura, Keisuke
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Maki, Shota; Yokosuka, Kazuhiro; Shibata, Yuichi; Fukui, Masahiro; Iemura, Keisuke
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Sawada, Sho; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke; Osawa, Takayasu
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