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Miyazaki K, Takehara M, Minomo K, Horie K, Takehara M, Yamasaki S, Saito T, Ohnuki T, Takano M, Shiotsu H, Iwata H, Vettese GF, Sarparanta MP, Law GTW, Grambow B, Ewing RC, Utsunomiya S. "Invisible" radioactive cesium atoms revealed: Pollucite inclusion in cesium-rich microparticles (CsMPs) from the Fukushima Daiichi Nuclear Power Plant. J Hazard Mater 2024; 470:134104. [PMID: 38569336 DOI: 10.1016/j.jhazmat.2024.134104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/14/2024] [Accepted: 03/19/2024] [Indexed: 04/05/2024]
Abstract
Understanding radioactive Cs contamination has been a central issue at Fukushima Daiichi and other nuclear legacy sites; however, atomic-scale characterization of radioactive Cs in environmental samples has never been achieved. Here we report, for the first time, the direct imaging of radioactive Cs atoms using high-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). In Cs-rich microparticles collected from Japan, we document inclusions that contain 27 - 36 wt% of Cs (reported as Cs2O) in a zeolite: pollucite. The compositions of three pollucite inclusions are (Cs1.86K0.11Rb0.19Ba0.22)2.4(Fe0.85Zn0.84X0.31)2.0Si4.1O12, (Cs1.19K0.05Rb0.19Ba0.22)1.7(Fe0.66Zn0.32X0.41)1.4Si4.6O12, and (Cs1.27K0.21Rb0.29Ba0.15)1.9(Fe0.60Zn0.32X0.69)1.6Si4.4O12 (X includes other cations). HAADF-STEM imaging of pollucite, viewed along the [111] zone axis, revealed an array of Cs atoms, which is consistent with a simulated image using the multi-slice method. The occurrence of pollucite indicates that locally enriched Cs reacted with siliceous substances during the Fukushima meltdowns, presumably through volatilization and condensation. Beta radiation doses from the incorporated Cs are estimated to reach 106 - 107 Gy, which is more than three orders of magnitude less than typical amorphization dose of zeolite. The atomic-resolution imaging of radioactive Cs is an important advance for better understanding the fate of radioactive Cs inside and outside of nuclear reactors damaged by meltdown events.
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Affiliation(s)
- Kanako Miyazaki
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Masato Takehara
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kenta Minomo
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kenji Horie
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan; Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan, Hayama, Kanagawa 240-0193, Japan
| | - Mami Takehara
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan
| | - Shinya Yamasaki
- Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Takumi Saito
- Nuclear Professional School, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Toshihiko Ohnuki
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Masahide Takano
- Japan Atomic Energy Agency, Nuclear Science Research Institute, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Hiroyuki Shiotsu
- Japan Atomic Energy Agency, Nuclear Science Research Institute, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Hajime Iwata
- Japan Atomic Energy Agency, Nuclear Fuel Cycle Engineering Laboratories, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194, Japan
| | - Gianni F Vettese
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Finland
| | - Mirkka P Sarparanta
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Finland
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Finland
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, the Nantes University, Nantes 44307, France
| | - Rodney C Ewing
- Earth & Planetary Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA 94305-2115 USA
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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Ang JWL, Bongrand A, Duval S, Donnard J, Jolis EM, Utsunomiya S, Minomo K, Koivula R, Siitari-Kauppi M, Law GTW. Detecting radioactive particles in complex environmental samples using real-time autoradiography. Sci Rep 2024; 14:5413. [PMID: 38443397 PMCID: PMC10915129 DOI: 10.1038/s41598-024-52876-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024] Open
Abstract
Radioactive particles often contain very high radioactivity concentrations and are widespread. They pose a potential risk to human health and the environment. Their detection, quantification, and characterization are crucial if we are to understand their impact. Here, we present the use of a real-time autoradiography gaseous detector (using parallel ionization multiplier) to expedite and improve the accuracy of radioactive particle screening in complex environmental samples. First, standard particles were used to assess the detector capabilities (spatial resolution, spectrometry, and artefact contributions), then, we applied the technique to more complex and environmentally relevant samples. The real-time autoradiography technique provides data with a spatial resolution (≲100 µm) suitable for particle analysis in complex samples. Further, it can differentiate between particles predominantly emitting alpha and beta radiation. Here, the technique is applied to radioactive cesium-rich microparticles collected from the Fukushima Daiichi nuclear exclusion zone, showing their accurate detection, and demonstrating the viability of real-time autoradiography in environmental scenarios. Indeed, for more complex samples (radioactive particles in a less radioactive heterogeneous background mix of minerals), the technique permits relatively high selectivity for radioactive particle screening (up to 61.2% success rate) with low false positive percentages (~ 1%).
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Affiliation(s)
- Joyce W L Ang
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland.
- Singapore Nuclear Safety and Research Initiative, National University of Singapore, Singapore, 138602, Singapore.
| | - Arthur Bongrand
- AI4R, 2 Rue Alfred Kastler, 44307, Nantes, France
- IMT Atlantique, Nantes Université, CNRS, 44000, Nantes, SUBATECH, France
| | - Samuel Duval
- AI4R, 2 Rue Alfred Kastler, 44307, Nantes, France
| | | | - Ester M Jolis
- Circular Economy Solutions Research Laboratory, Geological Survey of Finland GTK, 02151, Espoo, Finland
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka, 819-0395, Japan
| | - Kenta Minomo
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka, 819-0395, Japan
| | - Risto Koivula
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland
| | - Marja Siitari-Kauppi
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland
| | - Gareth T W Law
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland.
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Fueda K, Komiya T, Minomo K, Horie K, Takehara M, Yamasaki S, Shiotsu H, Ohnuki T, Grambow B, Law GW, Ewing R, Utsunomiya S. Occurrence of radioactive cesium-rich micro-particles (CsMPs) in a school building located 2.8 km south-west of the Fukushima Daiichi Nuclear Power Plant. Chemosphere 2023; 328:138566. [PMID: 37011818 DOI: 10.1016/j.chemosphere.2023.138566] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 06/19/2023]
Abstract
Radioactive Cs-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) are a potential health risk through inhalation. Little has been documented on the occurrence of CsMPs, particularly their occurrence inside buildings. In this study, we quantitatively analyze the distribution and number of CsMPs in indoor dust samples collected from an elementary school located 2.8 km to the southwest of FDNPP. The school had remained deserted until 2016. Then, using a modified version of the autoradiography-based "quantifying CsMPs (mQCP) method," we collected samples and determined the number of CsMPs and Cs radioactive fraction (RF) values of the microparticles (defined as total Cs activity from CsMPs/bulk Cs activity of the entire sample). The numbers of CsMPs ranged from 653 to 2570 particles/(g dust) and 296-1273 particles/(g dust) on the first and second floors of the school, respectively. The corresponding RFs ranged between 6.85 - 38.9% and 4.48-6.61%, respectively. The number of CsMPs and RF values in additional outdoor samples collected near the school building were 23-63 particles/(g dust or soil) and 1.14-1.61%, respectively. The CsMPs were most abundant on the school's first floor near to the entrance, and the relative abundance was higher near the stairs on the second floor, indicating a likely CsMP dispersion path through the building. Additional wetting of the indoor samples combined with autoradiography revealed that indoor dusts had a distinct absence of intrinsic, soluble Cs species, such as CsOH. These combined observations indicate that a significant amount of poorly soluble CsMPs were likely contained in initial radioactive airmass plumes from the FDNPP and that the microparticles penetrated buildings. CsMPs could still be abundant at the location, with locally high Cs activity in indoor environments near to openings.
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Affiliation(s)
- Kazuki Fueda
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Tatsuki Komiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kenta Minomo
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kenji Horie
- National Institute of Polar Research, 10-3, Midori-cho, Tachikawa-shi, Tokyo, 190-8518, Japan; Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa, 240-0193, Japan
| | - Mami Takehara
- National Institute of Polar Research, 10-3, Midori-cho, Tachikawa-shi, Tokyo, 190-8518, Japan
| | - Shinya Yamasaki
- Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 Japan
| | - Hiroyuki Shiotsu
- Nuclear Safety Research Center, Japan Atomic Energy Agency, 2-4, Shirakata-shirane, Tokai-Mura, Naka-Gun, Ibaraki, 319-1195, Japan
| | - Toshihiko Ohnuki
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, The University of Nantes, Nantes, 44307, France
| | - GarethT W Law
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, Finland
| | - RodneyC Ewing
- Department of Earth and Planetary Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA, 94305-2115, USA
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
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Fueda K, Takami R, Minomo K, Morooka K, Horie K, Takehara M, Yamasaki S, Saito T, Shiotsu H, Ohnuki T, Law GTW, Grambow B, Ewing RC, Utsunomiya S. Volatilization of B 4C control rods in Fukushima Daiichi nuclear reactors during meltdown: B-Li isotopic signatures in cesium-rich microparticles. J Hazard Mater 2022; 428:128214. [PMID: 35042164 DOI: 10.1016/j.jhazmat.2022.128214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/31/2021] [Accepted: 01/01/2022] [Indexed: 06/14/2023]
Abstract
Boron carbide control rods remain in the fuel debris of the damaged reactors in the Fukushima Daiichi Nuclear Power Plant, potentially preventing re-criticality; however, the state and stability of the control rods remain unknown. Sensitive high-resolution ion microprobe analyses have revealed B-Li isotopic signatures in radioactive Cs-rich microparticles (CsMPs) that formed by volatilization and condensation of Si-oxides during the meltdowns. The CsMPs contain 1518-6733 mg kg-1 of 10+11B and 11.99-1213 mg kg-1 of 7Li. The 11B/10B (4.15-4.21) and 7Li/6Li (213-406) isotopic ratios are greater than natural abundances (~4.05 and ~12.5, respectively), indicating that 10B(n,α)7Li reactions occurred in B4C prior to the meltdowns. The total amount of B released with CsMPs was estimated to be 0.024-62 g, suggesting that essentially all B remains in reactor Units 2 and/or 3 and is enough to prevent re-criticality; however, the heterogeneous distribution of B needs to be considered during decommissioning.
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Affiliation(s)
- Kazuki Fueda
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ryu Takami
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kenta Minomo
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kazuya Morooka
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kenji Horie
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan; Department of Polar Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Mami Takehara
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan
| | - Shinya Yamasaki
- Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Takumi Saito
- Nuclear Professional School, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hiroyuki Shiotsu
- Nuclear Safety Research Center, Japan Atomic Energy Agency, 2-4, Shirakata-shirane, Tokai-Mura, Naka-Gun, Ibaraki 319-1195, Japan
| | - Toshihiko Ohnuki
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, 00560 Helsinki, Finland
| | - Bernd Grambow
- SUBATECH, IMT Atlantique, CNRS-IN2P3, the University of Nantes, Nantes 44307, France
| | - Rodney C Ewing
- Department of Geological Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA 94305-2115, USA
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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Takechi M, Suzuki S, Nishimura D, Fukuda M, Ohtsubo T, Nagashima M, Suzuki T, Yamaguchi T, Ozawa A, Moriguchi T, Ohishi H, Sumikama T, Geissel H, Ishihara M, Aoi N, Chen RJ, Fang DQ, Fukuda N, Fukuoka S, Furuki H, Inabe N, Ishibashi Y, Itoh T, Izumikawa T, Kameda D, Kubo T, Lee CS, Lantz M, Ma YG, Matsuta K, Mihara M, Momota S, Nagae D, Nishikiori R, Niwa T, Ohnishi T, Okumura K, Ogura T, Sakurai H, Sato K, Shimbara Y, Suzuki H, Takeda H, Takeuchi S, Tanaka K, Uenishi H, Winkler M, Yanagisawa Y, Watanabe S, Minomo K, Tagami S, Shimada M, Kimura M, Matsumoto T, Shimizu YR, Yahiro M. Search for halo nucleus in Mg isotopes through the measurements of reaction cross sections towards the vicinity of neutron drip line. EPJ Web of Conferences 2014. [DOI: 10.1051/epjconf/20146602101] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Watanabe S, Minomo K, Tagami S, Shimada M, Kimura M, Takechi M, Fukuda M, Nishimura D, Suzuki T, Matsumoto T, Shimizu YR, Yahiro M. New candidate for deformed halo nucleus in Mg isotopes through analysis of reaction cross sections. EPJ Web of Conferences 2014. [DOI: 10.1051/epjconf/20146603095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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