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-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samplesLi, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.
Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02
Times Cited Count：2 Percentile：31.9(Chemistry, Analytical)no abstracts in English
Cs activity concentration in the aquatic insect 
(Tricoptera: Stenopsychidae) in the Ota River, Fukushima, JapanIshii, Yumiko*; Miura, Hikaru*; Jo, J.*; Tsuji, Hideki*; Saito, Rie; Koarai, Kazuma; Hagiwara, Hiroki; Urushidate, Tadayuki*; Nishikiori, Tatsuhiro*; Wada, Toshihiro*; et al.
PLOS ONE (Internet), 17(5), p.e0268629_1 - e0268629_17, 2022/05
Times Cited Count：3 Percentile：43.07(Multidisciplinary Sciences)We investigated the variability in Cs activity concentration in individual aquatic insects in detritivorous caddisfly () and carnivorous dobsonfly (
) larvae from the Ota River, Fukushima. Caddisfly larvae showed sporadically higher radioactivity, whereas no such outliers were observed in dobsonfly larvae. Autoradiography and scanning electron microscopy analyses confirmed that these caddisfly larvae samples contained radiocesium-bearing microparticles (CsMPs), which are insoluble Cs-bearing silicate glass particles. CsMPs were also found in potential food sources of caddisfly larvae, such as periphyton and drifting particulate organic matter, indicating that larvae may ingest CsMPs along with food particles of similar size. Although CsMPs distribution and uptake by organisms in freshwater ecosystems is relatively unknown, our study demonstrates that CsMPs can be taken up by aquatic insects.
Miura, Hikaru*; Kuribara, Yuichi; Takahashi, Yoshio*
Chikyu Kagaku, 55(4), p.122 - 131, 2021/12
Radiocesium-bearing microparticles (CsMPs), glassy water-resistant particles with highly concentrated radiocesium, were emitted by the Fukushima Daiichi Nuclear Power Plant accident. Since first discovery of CsMPs, a number of studies have analyzed the particles isolated from environmental samples and revealed their physical and chemical properties, distribution, and migration. This paper is intended to provide an overview focusing on the environmental transport and impact of CsMPs. First, we begin by reviewing the relationship between deposition areas and atmospheric plumes of CsMPs found on land. Next, search and separation methods for CsMPs will be described. Then, secondary transport via rivers and effect of CsMPs on Kd values of Cs in rivers will be discussed. Finally, CsMPs found in the ocean and their difference from terrestrial ones will be summarized.
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：43 Percentile：96.93(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.
Miura, Hikaru*; Ishimaru, Takashi*; Ito, Yukari*; Kuribara, Yuichi; Otosaka, Shigeyoshi*; Sakaguchi, Aya*; Misumi, Kazuhiro*; Tsumune, Daisuke*; Kubo, Atsushi*; Higaki, Shogo*; et al.
Scientific Reports (Internet), 11, p.5664_1 - 5664_11, 2021/03
Times Cited Count：13 Percentile：67.27(Multidisciplinary Sciences)For the first time, we isolated and investigated seven CsMPs (radioactive caesium-bearing microparticles) from marine particulate matter and sediment. From the elemental composition, the 
Cs/Cs activity ratio, and the Cs activity per unit volume results, we inferred that the five CsMPs collected from particulate matter were emitted from Unit 2 of the FDNPP, whereas the two CsMPs collected from marine sediment were possibly emitted from Unit 3. The presence of CsMPs can cause overestimation of the solid-water distribution coefficient of Cs in marine sediments and particulate matter and a high apparent radiocaesium concentration factor for marine biota. CsMPs emitted from Unit 2, which were collected from the estuary of a river that flowed through a highly contaminated area, may have been deposited on land and then transported by the river. By contrast, CsMPs emitted from Unit 3 were possibly transported eastward by the wind and deposited directly onto the ocean surface.
Sumida, Kazuki; Sakuraba, Yuya*; Masuda, Keisuke*; Kono, Takashi*; Kakoki, Masaaki*; Goto, Kazuki*; Zhou, W.*; Miyamoto, Koji*; Miura, Yoshio*; Okuda, Taichi*; et al.
Communications Materials (Internet), 1, p.89_1 - 89_9, 2020/11
Miura, Hikaru*; Kuribara, Yuichi; Yamamoto, Masayoshi*; Sakaguchi, Aya*; Yamaguchi, Noriko*; Sekizawa, Oki*; Nitta, Kiyofumi*; Higaki, Shogo*; Tsumune, Daisuke*; Itai, Takaaki*; et al.
Scientific Reports (Internet), 10, p.11421_1 - 11421_9, 2020/07
Times Cited Count：18 Percentile：68.95(Multidisciplinary Sciences)Takahashi, Yoshio*; Sakaguchi, Aya*; Fan, Q.*; Tanaka, Kazuya; Miura, Hikaru*; Kurihara, Yuichi*
Behavior of Radionuclides in the Environment I; Function of Particles in Aquatic System, p.115 - 150, 2020/00
Times Cited Count：0 Percentile：0.59(Environmental Sciences)Igarashi, Yasuhito*; Kogure, Toshihiro*; Kuribara, Yuichi; Miura, Hikaru*; Okumura, Taiga*; Satou, Yukihiko; Takahashi, Yoshio*; Yamaguchi, Noriko*
Journal of Environmental Radioactivity, 205-206, p.101 - 118, 2019/09
Times Cited Count：65 Percentile：70.02(Environmental Sciences)Scientists face challenge in identifying the radioactive materials which are found as dotted images on various imaging plate (IP) autoradiographic photos of radioactively contaminated materials by the Fukushima Dai-ichi Nuclear Power Plant (F1NPP, or FDNPP) accident, such as air filter, fugitive dust, surface soil, agricultural materials, and water-shed samples. It has been revealed that they are minute particles with distinct morphology and elemental composition with high specific radioactivity, and different from those of the so-called Chernobyl hot particles. Basically, they are glassy particles once molten, composed of Si, O, Fe, Zn etc. with highly concentrated radiocaesium, which can be called as radiocaesium-bearing microparticles (CsMP). At present, CsMP can be classified into two types, Types-A and -B, which are characterized by different specific radioactivity, Cs/Cs ratio, size and morphology, and geographic distribution around F1NPP. Such studies on the CsMP from various aspects have provided valuable information about what happened in the nuclear reactors during the F1NPP accident and fates of the CsMP in the environment. This review first provides a retrospective view on the research history of the CsMP, which is helpful to understand the unique character of the CsMP. Subsequently, more details about the current understanding of the natures of these hot particles, such as origin, morphology, chemical compositions, thermal properties, water-solubility, and secondary migration of CsMP in river and ocean systems are described with future prospects.
) of radiocesium in the Kuchibuto River in FukushimaMiura, Hikaru*; Kurihara, Yuichi*; Sakaguchi, Aya*; Tanaka, Kazuya; Yamaguchi, Noriko*; Higaki, Shogo*; Takahashi, Yoshio*
Geochemical Journal, 52(2), p.145 - 154, 2018/00
Times Cited Count：48 Percentile：93.68(Geochemistry & Geophysics)Solid-water distribution coefficient () of radiocesium in rivers is apparently increased due to the possible presence of highly radioactive radiocesium-bearing microparticles (CsMPs) in the solid phase. In this study, we evaluated the contribution of CsMPs to apparent Kd values. The ratio of the radioactivity of the separated CsMPs to the total radiocesium on fluvial suspended particles ranged from 0 to 46%. This means that the existence of CsMPs in fluvial suspended partcles did not change apparent Kd values in order magnitude.
Inagaki, Shigeru*; Takenaga, Hidenobu; Ida, Katsumi*; Isayama, Akihiko; Tamura, Naoki*; Takizuka, Tomonori; Shimozuma, Takashi*; Kamada, Yutaka; Kubo, Shin*; Miura, Yukitoshi; et al.
Nuclear Fusion, 46(1), p.133 - 141, 2006/01
Times Cited Count：54 Percentile：85.24(Physics, Fluids & Plasmas)no abstracts in English
Inagaki, Shigeru*; Takenaga, Hidenobu; Ida, Katsumi*; Isayama, Akihiko; Tamura, Naoki*; Takizuka, Tomonori; Shimozuma, Takashi*; Kamada, Yutaka; Kubo, Shin*; Miura, Yukitoshi; et al.
Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11
no abstracts in English
Tamai, Hiroshi; Matsukawa, Makoto; Kurita, Genichi; Hayashi, Nobuhiko; Urata, Kazuhiro*; Miura, Yushi; Kizu, Kaname; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Kudo, Yusuke; et al.
Plasma Science and Technology, 6(1), p.2141 - 2150, 2004/02
Times Cited Count：2 Percentile：6.49(Physics, Fluids & Plasmas)The dominant issue for the the modification program of JT-60 (JT-60SC) is to demonstrate the steady state reactor relevant plasma operation. Physics design on plasma parameters, operation scenarios, and the plasma control method are investigated for the achievement of high-
. Engineering design and the R&D on the superconducting magnet coils, radiation shield, and vacuum vessel are performed. Recent progress in such physics and technology developments is presented.
Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Chujo, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.
Nuclear Fusion, 43(7), p.606 - 613, 2003/07
no abstracts in English
Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Cho, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.
Nuclear Fusion, 43(7), p.606 - 613, 2003/07
Times Cited Count：33 Percentile：69.14(Physics, Fluids & Plasmas)no abstracts in English
Nagata, M.*; Fukumoto, Naoyuki*; Ogawa, Hiroaki; Ogawa, Toshihide; Uehara, Kazuya; Niimi, Hironobu*; Shibata, Takatoshi; Suzuki, Yoshio; Miura, Yukitoshi; Kayukawa, Naoyuki*; et al.
Nuclear Fusion, 41(11), p.1687 - 1694, 2001/11
Times Cited Count：12 Percentile：38.18(Physics, Fluids & Plasmas)no abstracts in English
Ninomiya, Kazuhiko; Nakagaki, Reiko*; Kubo, Kenya*; Ishida, Katsuhiko*; Kobayashi, Yoshio*; Matsuzaki, Teiichiro*; Matsumura, Hiroshi*; Miura, Taichi*; Higemoto, Wataru; Shinohara, Atsushi*
no journal, ,
no abstracts in English
Yoshioka, Masahiro*; Fukui, Toshiki*; Miura, Nobuyuki; Tsukada, Takeshi*
no journal, ,
The basic research programs for the next generation vitrification technology, which are commissioned project from Ministry of Economy, Trade and Industry of Japan to IHI Corporation (IHI), Japan Nuclear Fuel Limited (JNFL), Japan Atomic Energy Agency (JAEA) and Central Research Institute of Electric Power Industry (CRIEPI), have been implemented from 2014 for developing the advanced vitrification technology of low level wastes and high level liquid wastes (HLLW). In these programs, the developmental works such as the high waste loading glass, the alternate glasses of current borosilicate glasses including glass-ceramics and the minor actinide adsorbent glasses have been entrusted with the above organizations.
Miura, Hikaru*; Kuribara, Yuichi; Yamamoto, Masayoshi*; Sakaguchi, Aya*; Higaki, Shogo*; Takahashi, Yoshio*
no journal, ,
A synchrotron radiation X-ray analysis was performed on radioactive particles released into the environment due to the Fukushima Dai-ichi Nuclear Power Plant accident, uranium particles (4 valence and 6 valence) with a size of several microns were present in the particles from the Unit 1. Since these uranium particles also contain zirconium, which is considered to be derived from the fuel cladding, it was presumed that the eutectic mixture of the fuel in the reactor and its cladding was incorporated into the radioactive particulates and released into the environment.
MnGa filmsSumida, Kazuki; Sakuraba, Yuya*; Masuda, Keisuke*; Kono, Takashi*; Kakoki, Masaaki*; Goto, Kazuki*; Zhou, W.*; Miyamoto, Koji*; Miura, Yoshio*; Okuda, Taichi*; et al.
no journal, ,
no abstracts in English
