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Igarashi J, Ninomiya K, Zheng J, Zhang Z, Fukuda M, Aono T, Minowa H, Yoshikawa H, Sueki K, Satou Y, Shinohara A. Fukushima Daiichi Nuclear Power Plant Accident: Understanding Formation Mechanism of Radioactive Particles through Sr and Pu Quantities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:14823-14830. [PMID: 39129255 DOI: 10.1021/acs.est.4c03428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
The Fukushima Daiichi Nuclear Power Plant accident released considerable radionuclides into the environment. Radioactive particles, composed mainly of SiO2, emerged as distinctive features, revealing insights into the accident's dynamics. While studies extensively focused on high-volatile radionuclides like Cs, investigations into low-volatile nuclides such as 90Sr and Pu remain limited. Understanding their abundance in radioactive particles is crucial for deciphering the accident's details, including reactor temperatures and injection processes. Here, we aimed to determine 90Sr and Pu amounts in radioactive particles and provide essential data for understanding the formation processes and conditions within the reactor during the accident. We employed radiochemical analysis on nine radioactive particles and determined the amounts of 90Sr and Pu in these particles. 90Sr and Pu quantification in radioactive particles showed that the 90Sr/137Cs radioactivity ratio (corrected to March 11, 2011) aligned with core temperature expectations. However, the 239+240Pu/137Cs activity ratio indicated nonvolatile Pu introduction, possibly through fuel fragments. Analyzing 90Sr and Pu enhances our understanding of the Fukushima Daiichi accident. Deviations in 239+240Pu/137Cs activity ratios underscore nonvolatile processes, emphasizing the accident's complexity. Future research should expand this data set for a more comprehensive understanding of the accident's nuances.
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Affiliation(s)
- Junya Igarashi
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Kazuhiko Ninomiya
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jian Zheng
- Institute for Radiological Science, National Institute for Quantum Science and Technology (QST), 491 Anagawa, Inage, Chiba 263-8555, Japan
| | - Zijian Zhang
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Miho Fukuda
- Institute for Radiological Science, National Institute for Quantum Science and Technology (QST), 491 Anagawa, Inage, Chiba 263-8555, Japan
- Research Department, Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu Town, Fukushima 963-7700, Japan
| | - Tatsuo Aono
- Institute for Radiological Science, National Institute for Quantum Science and Technology (QST), 491 Anagawa, Inage, Chiba 263-8555, Japan
| | - Haruka Minowa
- The Jikei University School of Medicine, 3-25 Nishishinbashi, Minato Ward, Tokyo 105-0003, Japan
| | - Hideki Yoshikawa
- The Jikei University School of Medicine, 3-25 Nishishinbashi, Minato Ward, Tokyo 105-0003, Japan
| | - Keisuke Sueki
- Graduate School of Pure and Material, Tsukuba University, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency, 790-1 Otsuka, Motooka, Tomioka, Futaba, Fukushima 979-1151, Japan
| | - Atsushi Shinohara
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Faculty of Health Science, Osaka Aoyama University, 2-11-1 Niina, Minoh, Osaka 562-8580, Japan
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2
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Laffolley H, Journeau C, Grambow B. Simulant molten core-concrete interaction experiments in view of understanding Fukushima Daiichi Nuclear Power Station Cs-bearing particles generation mechanism. Sci Rep 2024; 14:6611. [PMID: 38504092 PMCID: PMC11344152 DOI: 10.1038/s41598-024-56972-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 03/13/2024] [Indexed: 03/21/2024] Open
Abstract
The Fukushima Daiichi accident resulted in the release of a novel form of radioactive Cs contamination into the environment, called Cs-bearing microparticles (CsMP). CsMPs constitute a substantial portion of the radioactive pollution near the nuclear power station and traveled beyond several hundred kilometers. Extensive characterization of the CsMPs revealed an amorphous silica matrix, along with Cs and other minor or trace elements such as Fe and Zn. This study explores the unclear generation mechanism of CsMPs by conducting experimental molten core concrete interactions (MCCI) as a source of Si and analyzing the resultant aerosols. The findings demonstrate that MCCI is in capacity to produce spherical submicronic and micronic particles, primarily composed of amorphous silica and incorporating elements akin to CsMPs. A humid atmosphere is found to favour an even closer chemical composition. Examination of the internal structure of the synthesized particles unveils pores and numerous crystalline nanoinclusions possibly serving as nucleation sites for CsMP formation through the condensation of Si-rich vapors.
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Affiliation(s)
- Hugo Laffolley
- CEA, DES, IRESNE, DTN, Severe Accident Experimental Laboratory, Cadarache, 13108, St-Paul-lez-Durance, France
| | - Christophe Journeau
- CEA, DES, IRESNE, DTN, Severe Accident Experimental Laboratory, Cadarache, 13108, St-Paul-lez-Durance, France.
| | - Bernd Grambow
- SUBATECH (IMT Atlantique, CNRS-IN2P3, University of Nantes), 44307, Nantes, France
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3
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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] [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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4
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Takaku Y, Higaki S, Hirota M, Kagi H. Radiocesium-bearing microparticles found in dry deposition fallout samples immediately after the Fukushima nuclear accident in the Kanto region, Japan. Sci Rep 2023; 13:21826. [PMID: 38071366 PMCID: PMC10710400 DOI: 10.1038/s41598-023-49158-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
Radiocesium released by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident still exists in the environment in two forms: adsorbed species on mineral particles in the soil and microparticles containing radiocesium mainly composed of silicate glass (CsMPs). CsMPs are dispersed not only around the FDNPP but also over a wide area of the Kanto region. The behavior and characteristics of CsMPs must be investigated to evaluate the impact of the FDNPP accident. Deposited particles including radiocesium were wiped from metal handrails on balconies and car hoods using tissue papers at six locations in the Kanto region (Tokai village, Ushiku City, Abiko City, Chiba City, Kawaguchi City, and Arakawa Ward) between March 15 and 21, 2011. CsMPs were isolated from the samples, and their characteristics were investigated. In total, 106 CsMPs derived from Unit 2 were successfully separated from 13 tissue paper samples. The radiation images of the two types of CsMPs discovered in Ushiku City demonstrate that CsMPs can easily become susceptible to fragmentation over time, even in the absence of weathering effects.
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Affiliation(s)
- Yuki Takaku
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Shogo Higaki
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
| | - Masahiro Hirota
- Research Center for Supports to Advanced Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| | - Hiroyuki Kagi
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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5
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Ohnuki T, Ye J, Kato T, Liu J, Takano M, Kozai N, Utsunomiya S. Chemical species of cesium and iodine in condensed vaporized microparticles formed by melting nuclear fuel components with concrete materials. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:1204-1212. [PMID: 37317925 DOI: 10.1039/d3em00074e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In this study, we report chemical species of Cs and I in condensed vaporized particles (CVPs) produced by melting experiments using nuclear fuel components containing CsI with concrete. Analyses of CVPs by SEM with EDX showed the formation of many round particles containing Cs and I of diameters less than ∼20 μm. X-ray absorption near-edge-structure and SEM-EDX analyses showed two kinds of particles: one containing large amounts of Cs and I, suggesting the presence of CsI, and the other containing small amounts of Cs and I with large Si content. When CVSs were placed in contact with deionized water, most of the CsI from both particles was dissolved. In contrast, some fractions of Cs remained from the latter particles and possessed different chemical species from CsI. In addition, the remaining Cs was concomitantly present with Si, resembling chemical components in the highly radioactive cesium-rich microparticles (CsMPs) released by nuclear plant accidents into the surrounding environments. These results strongly suggest that Cs was incorporated in CVSs along with Si by melting nuclear fuel components to form sparingly-soluble CVMPs.
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Affiliation(s)
- Toshihiko Ohnuki
- School of Resource Environment and Safety Engineering, University of South China, Zhengxiang District, Hengyang, Hunan, 421001, China.
- Fukushima Reconstruction and Revitalization Unit, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
- The Institute of Human Culture Studies (IHCS), Otsuma Women's University, 12 Sanbancho, Chiyoda-ku, Tokyo 102-8357, Japan
| | - Jian Ye
- School of Resource Environment and Safety Engineering, University of South China, Zhengxiang District, Hengyang, Hunan, 421001, China.
| | - Tomoaki Kato
- Fukushima Reconstruction and Revitalization Unit, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), Tomioka, Fukushima, Japan
| | - Jiang Liu
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), Tomioka, Fukushima, Japan
| | - Masahide Takano
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), Tomioka, Fukushima, Japan
| | - Naofumi Kozai
- Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, 319-1195, Japan
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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6
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Ang JWL, Bongrand A, Duval S, Donnard J, Parkkonen J, Utsunomiya S, Koivula R, Siitari-Kauppi M, Law GTW. Improved Radio-Cesium Detection Using Quantitative Real-Time Autoradiography. ACS OMEGA 2023; 8:22523-22535. [PMID: 37396268 PMCID: PMC10308591 DOI: 10.1021/acsomega.3c00728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/02/2023] [Indexed: 07/04/2023]
Abstract
Cesium-134 and -137 are prevalent, long-lived, radio-toxic contaminants released into the environment during nuclear accidents. Large quantities of insoluble, respirable Cs-bearing microparticles (CsMPs) were released into the environment during the Fukushima Daiichi nuclear accident. Monitoring for CsMPs in environmental samples is essential to understand the impact of nuclear accidents. The current detection method used to screen for CsMPs (phosphor screen autoradiography) is slow and inefficient. We propose an improved method: real-time autoradiography that uses parallel ionization multiplier gaseous detectors. This technique permits spatially resolved measurement of radioactivity while providing spectrometric data from spatially heterogeneous samples-a potential step-change technique for use after nuclear accidents for forensic analysis. With our detector configuration, the minimum detectable activities are sufficiently low for detecting CsMPs. Further, for environmental samples, sample thickness does not detrimentally affect detector signal quality. The detector can measure and resolve individual radioactive particles ≥465 μm apart. Real-time autoradiography is a promising tool for radioactive particle detection.
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Affiliation(s)
- Joyce W. L. Ang
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, Helsinki 00014, Finland
- Singapore
Nuclear Safety and Research Initiative, National University of Singapore, 138602 Singapore
| | - Arthur Bongrand
- AI4R, 2 rue Alfred Kastler, 44307 Nantes, France
- IMT
Atlantique, Nantes Université, CNRS, SUBATECH, F-44000 Nantes, France
| | - Samuel Duval
- AI4R, 2 rue Alfred Kastler, 44307 Nantes, France
| | | | - Joni Parkkonen
- Department
of Physics, University of Jyväskylä, Jyväskylä 40500, Finland
| | - Satoshi Utsunomiya
- Department
of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Risto Koivula
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, Helsinki 00014, Finland
| | - Marja Siitari-Kauppi
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, Helsinki 00014, Finland
| | - Gareth T. W. Law
- Radiochemistry
Unit, Department of Chemistry, The University
of Helsinki, Helsinki 00014, Finland
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7
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Laffolley H, Journeau C, Thilliez S, Grambow B. Thermodynamics of aerosols during a molten core-concrete interaction at Fukushima Daiichi Unit 2 estimated conditions. ANN NUCL ENERGY 2023. [DOI: 10.1016/j.anucene.2023.109770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
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8
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Okumura T, Yamaguchi N, Kogure T. Dissolution behavior of radiocesium-bearing microparticles as a function of solution compositions. Sci Rep 2023; 13:4307. [PMID: 36922544 PMCID: PMC10017807 DOI: 10.1038/s41598-023-31519-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
More than a decade has passed since the Fukushima nuclear accident in 2011 and contamination around the nuclear power plant is primarily caused by 137Cs. One of the materials retaining radiocesium in the environment is radiocesium-bearing silicate glass microparticles (CsMPs), which have not been reported in previous nuclear accidents. Although the prediction of environmental fates of CsMPs is of interest because of their extremely high specific radioactivity, knowledge about their physicochemical properties is still limited. Here we show that the dissolution behavior of CsMPs is comparable to that of silica-rich glass and significantly depends on the surrounding environment. CsMP dissolution experiments were conducted in solutions with various solute components and pH levels at 60 °C. In neutral and basic solutions, the estimated dissolution rate was accelerated by alkali ions such as Na+, which is known to play a catalytic role for the dissolution of silica. In contrast, the dissolution in acid was slow even in the presence of alkali ions. The dissolution under acid conditions was possibly retarded by a thin amorphous silica layer formed on the CsMP surfaces. Such characteristics of the dissolution are consistent with that of silica-rich glass. To infer the dissolution behavior of CsMPs in the human body, the dissolution rate in Ringer's solution at 37 °C was estimated as 1.00 ± 0.37 μm/year.
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Affiliation(s)
- Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-0033, Japan.
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-0033, Japan
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9
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Otaki JM, Sakauchi K, Taira W. The second decade of the blue butterfly in Fukushima: Untangling the ecological field effects after the Fukushima nuclear accident. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2022; 18:1539-1550. [PMID: 35475314 DOI: 10.1002/ieam.4624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 02/24/2022] [Accepted: 04/24/2022] [Indexed: 06/14/2023]
Abstract
Many field observations of the biological effects of the Fukushima nuclear accident have been reported in the first decade after the accident. A series of observational and experimental studies have demonstrated causal adverse effects on the pale grass blue butterfly even at the low-level radiation exposure in the "field," contrary to the dosimetric view that insects are generally tolerant of radiation exposure. However, it has been demonstrated that the pale grass blue butterfly is tolerant of high oral doses of anthropogenic radioactive cesium (137 Cs) under "laboratory" conditions. This field-laboratory paradox can be explained by ecological field effects; for example, radiation stress in the field causes physiological and biochemical changes in the host plant, which then trophically affects butterfly larvae. The second decade of butterfly-based Fukushima research will be devoted to demonstrating how such adverse field effects occur. Changes in the host plant's nutritional contents likely affect butterfly physiology. The host plant may also upregulate secondary metabolites that affect herbivorous insects. The plant may be affected by changes in endophytic soil microbes in radioactively contaminated areas. If demonstrated, these results will reveal that the delicate ecological balances among the butterfly, its host plant, and soil microbes have been affected by radioactive pollution in Fukushima, which has important implications for environmental policies and human health. Integr Environ Assess Manag 2022;18:1539-1550. © SETAC.
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Affiliation(s)
- Joji M Otaki
- The BCPH Unit of Molecular Physiology, Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa, Japan
| | - Ko Sakauchi
- The BCPH Unit of Molecular Physiology, Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa, Japan
| | - Wataru Taira
- The BCPH Unit of Molecular Physiology, Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa, Japan
- Research Planning Office, University of the Ryukyus, Okinawa, Japan
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10
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Johansen MP, Child DP, Collins R, Cook M, Davis J, Hotchkis MAC, Howard DL, Howell N, Ikeda-Ohno A, Young E. Radioactive particles from a range of past nuclear events: Challenges posed by highly varied structure and composition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156755. [PMID: 35718169 DOI: 10.1016/j.scitotenv.2022.156755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Mathew P Johansen
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia.
| | - David P Child
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | | | - Megan Cook
- International Atomic Energy Agency (IAEA), Environmental Laboratories, Monaco
| | - Joel Davis
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Michael A C Hotchkis
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Daryl L Howard
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Nicholas Howell
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Atsushi Ikeda-Ohno
- Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan
| | - Emma Young
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
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11
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Laffolley H, Journeau C, Delacroix J, Grambow B, Suteau C. Synthesis of Fukushima Daiichi Cs-bearing microparticles through molten core-concrete interaction in nitrogen atmosphere. NUCLEAR MATERIALS AND ENERGY 2022. [DOI: 10.1016/j.nme.2022.101253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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12
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Rizaal M, Nakajima K, Saito T, Osaka M, Okamoto K. High-Temperature Gaseous Reaction of Cesium with Siliceous Thermal Insulation: The Potential Implication to the Provenance of Enigmatic Fukushima Cesium-Bearing Material. ACS OMEGA 2022; 7:29326-29336. [PMID: 36033724 PMCID: PMC9404493 DOI: 10.1021/acsomega.2c03525] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Here, we report an investigation of the gas-solid reaction between cesium hydroxide (CsOH) and siliceous (calcium silicate) thermal insulation at high temperature, which is postulated as the origin for the formation mechanism of cesium-bearing material emitted from the Fukushima Daiichi nuclear power plant. A developed reaction furnace consisting of two heating compartments was used to study the reaction at temperatures of 873, 973, and 1073 K. Under the influence of hydrogen-steam atmospheric conditions (H2/H2O = 0.2), the reaction between cesium hydroxide vapor and solid thermal insulation was confirmed to occur at temperatures of 973 and 1073 K with the formation of dicalcium silicate (Ca2SiO4) and cesium aluminum silicate (CsAlSiO4). Water-dissolution analyses of the reaction products have demonstrated their stability, in particular, CsAlSiO4. Constituent similarity of the field-observed cesium-bearing materials near the Fukushima Daiichi nuclear power plants with CsAlSiO4 suggests for the first time that gaseous reaction between CsOH with calcium silicate thermal insulation could be one of the original formation mechanisms of the cesium-bearing materials.
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Affiliation(s)
- Muhammad Rizaal
- Nuclear
Science and Engineering Center, Japan Atomic
Energy Agency, 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Kunihisa Nakajima
- Nuclear
Science and Engineering Center, Japan Atomic
Energy Agency, 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Takumi Saito
- Nuclear
Professional School, School of Engineering, The University of Tokyo, 2-22 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1188, Japan
| | - Masahiko Osaka
- Nuclear
Science and Engineering Center, Japan Atomic
Energy Agency, 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Koji Okamoto
- Nuclear
Professional School, School of Engineering, The University of Tokyo, 2-22 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1188, Japan
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13
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The formation mechanism of radiocesium-bearing microparticles derived from the Fukushima Daiichi nuclear power plant using electron microscopy. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08434-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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14
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Nishiyama H, Kamida S, Moriizumi J, Yamazawa H. Analysis of volatile nuclides' behavior in the atmosphere released due to the FDNPP accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 249:106894. [PMID: 35576776 DOI: 10.1016/j.jenvrad.2022.106894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/11/2022] [Accepted: 04/25/2022] [Indexed: 06/15/2023]
Abstract
The volatile nuclides, 131I, 132I, and 132Te, which were released in large quantities during the early stage of the Fukushima Dai-ichi Nuclear Power Plant accident, are the most dominant ones in determining the impact on the public and the environment. Since the behavior of these nuclides in the environment and their effects on human health differ depending on their physicochemical forms, it is necessary to understand more about the release fraction and the deposition process of each form. In this study, a behavior model was developed to calculate physical and chemical processes of organic, inorganic, and particulate 131I and 132I, and gaseous and particulate 132Te. This behavior model was used to estimate the physicochemical composition of iodine at the time of release, the 132Te/132I activity ratio at the time of release, and the dry deposition velocity of 132Te. The estimation was performed for five plumes transported during the period from March 14 to 21, 2011, and the estimated values were obtained by comparing with the values measured in previous studies. As a result of the estimation, the organic iodine fraction at the time of release was estimated to be 0.1 or less for most plumes, while a significantly higher value of 0.3 was estimated for the plume released in the night of March 14. This result implied that the possibility of formation and release of organic iodine in the liquid phase in Unit 3, which was considered to be the source of this plume. As for the 132Te/132I ratio at the time of release, it was estimated to be about 0.3-0.4 for most plumes, while it was about 1 in the plume released in the early morning of March 15, which is consistent with the release process in Unit 2 on the night of 14 and early morning of the 15. In addition, a remarkably high dry deposition velocity of 132Te was estimated in this plume, which was consistent with the existence of radiocaesium-bearing microparticles (CsMP) with a particle size of a few micrometers that had been found to be specific to this plume.
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Affiliation(s)
- Hikaru Nishiyama
- Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
| | - Shunsuke Kamida
- Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
| | - Jun Moriizumi
- Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
| | - Hiromi Yamazawa
- Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
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Li P, Gong Y, Lu W, Sakagami N, Mo Z, Komatsuzaki M. Radiocesium distribution caused by tillage inversion affects the soil-to-crop transfer factor and translocation in agroecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154897. [PMID: 35367255 DOI: 10.1016/j.scitotenv.2022.154897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 06/14/2023]
Abstract
This study reports the translocation of cesium-137 (137Cs) into deep soil layers, and the 137Cs transfer from soil to soybean in farmland under three tillage (no tillage, NT; rotary cultivation, RC; moldboard plow; MP) treatments and an undisturbed grassland (GL) at eight years after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on 11 March 2011 in Japan. Tillage influences the 137Cs distribution in the 0-30 cm of soil; the distribution of 137Cs in the soil was uniform under RC and MP treatments, while in the grassland, most 137Cs was concentrated on the soil surface (0-2.5 cm). The center of vertical 137Cs radioactivity concentration (the thickness of the soil from surface which containing half of the 137Cs inventory) in GL was 5.5 cm, which was shallower than that in farmland (9.5 cm in NT, 13.6 cm in RC and 15.2 cm in MP). Hence, the total translocation distance of 137Cs 8 years after FDNPP accident showed the following trend: GL (2.4 cm) < NT (7.0 cm) < RC (10.0 cm) < MP (12.3 cm). Meanwhile, a significant positive correlation was observed between 137Cs radioactivity concentration and organic carbon and nitrogen content in the soil. However, the 137Cs radioactivity concentration in soybean grains was negatively correlated with the center of vertical 137Cs radioactivity concentration but positively correlated with the ratio of exchangeable 137Cs (ExCs) and K content in the soil. The ExCs/K and 137Cs distributions in the soil were combined into a statistical model to predict the 137Cs radioactivity concentration in soybean grain. The results revealed the magnitude of the impact of 137Cs distribution on the 137Cs transfer from soil to crop. The addition of the 137Cs distribution dramatically improved the accuracy of the prediction model of 137Cs radioactivity concentration in soybean.
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Affiliation(s)
- Peiran Li
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Yingting Gong
- Institute of Agricultural Resources and Environment, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Wenyi Lu
- College of Agriculture, Ibaraki University, 3-21-1, Chuuo, Ami, Inashiki, Ibaraki 300-0393, Japan
| | - Nobuo Sakagami
- College of Agriculture, Ibaraki University, 3-21-1, Chuuo, Ami, Inashiki, Ibaraki 300-0393, Japan
| | - Zhaowen Mo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Masakazu Komatsuzaki
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan; Center for International Field Agriculture Research & Education, Ibaraki University, 3-21-1, Ami, Inashiki, Ibaraki 300-0393, Japan.
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Yamasaki S, Saito H, Nakamura T, Morooka K, Sueki K, Utsunomiya S. Gravitational separation of 137Cs contaminated soil in Fukushima environment: Density dependence of 137Cs activity and application to volume reduction. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 246:106846. [PMID: 35240395 DOI: 10.1016/j.jenvrad.2022.106846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 02/10/2022] [Accepted: 02/15/2022] [Indexed: 06/14/2023]
Abstract
Behavior of radiocesium in Fukushima after its deposition is mainly controlled by mobility of soil components, of which the density is one of the parameters governing the mobility; however, little information is available on the density of soil components associated with radiocesium in environment. Furthermore, the reduction of the volume of radiocesium-contaminated soil in the interim storage is highly demanded. In this study, we developed a gravitational separation method using a sodium polytungstate (SPT) solution combined with size fractionation to understand the relation between 137Cs activity and the density of surface soil components and evaluate the feasibility of the method for the volume reduction of the contaminated soil. In all soil samples examined, 137Cs concentration of the small size (<0.063 mm) and high-density (2.4-2.8 g cm-3) fraction was the highest among the separated fractions, whereas most of the radiocesium-rich micro-particles were distributed in the small size (<0.063 mm) and low density (<2.4 g cm-3) fraction. Although ultrasonication improved the size separation efficiency, a single-step gravitational separation method using an SPT solution with a density of 2.4 g cm-3 without size separation and ultrasonication revealed that the 137Cs concentration on 50°C-dry weight basis in the dense (>2.4 g cm-3) fraction was 25.6-82.7% lower than that of the bulk sample for all soil samples. In particular, for the samples with a bulk 137Cs concentration of 29.6 Bq g-1 50°C-dry weight, the 137Cs concentration in the fraction was below the safety treatment requirement (i.e., 8 Bq g-1). Therefore, single-step gravitational separation may be used for the volume reduction of contaminated soils.
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Affiliation(s)
- Shinya Yamasaki
- Department of Chemistry, 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.
| | - Hikaru Saito
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Tsukasa Nakamura
- Graduate School of Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Kazuya Morooka
- Department of Chemistry, Kyushu University, Motooka 744, Nishi-Ku, Fukuoka, 819-0395, Japan
| | - Keisuke Sueki
- Department of Chemistry, 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
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, Motooka 744, Nishi-Ku, Fukuoka, 819-0395, Japan
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Matsuya Y, Hamada N, Yachi Y, Satou Y, Ishikawa M, Date H, Sato T. Inflammatory Signaling and DNA Damage Responses after Local Exposure to an Insoluble Radioactive Microparticle. Cancers (Basel) 2022; 14:cancers14041045. [PMID: 35205797 PMCID: PMC8869995 DOI: 10.3390/cancers14041045] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/09/2022] [Accepted: 02/15/2022] [Indexed: 12/30/2022] Open
Abstract
Simple Summary A cesium-bearing microparticle (Cs-BMP) is an insoluble radioactive microparticle possessing high specific radioactivity, which was discovered after the incident at the Fukushima nuclear power plant. Due to their insoluble nature, such Cs-BMPs are assumed to adhere in the long term to normal tissue, leading to chronic local exposure. However, radiation risk due to the intake of internal exposure to radioactive cesium is conventionally estimated from the organ dose given by uniform exposure to soluble cesium. As such, it is critical to clarify the normal tissue effects posed by heterogeneous exposure to Cs-BMPs. This in vitro study reports on the relationship between the inflammatory responses and DNA damage induction during local exposure to a Cs-BMP. Abstract Cesium-bearing microparticles (Cs-BMPs) can reach the human respiratory system after inhalation, resulting in chronic local internal exposure. We previously investigated the spatial distribution of DNA damage induced in areas around a Cs-BMP; however, the biological impacts have not been fully clarified due to the limited amount of data. Here, we investigated the inflammatory signaling and DNA damage responses after local exposure to a Cs-BMP in vitro. We used two normal human lung cell lines, i.e., lung fibroblast cells (WI-38) and bronchial epithelial cells (HBEC3-KT). After 24 h exposure to a Cs-BMP, inflammation was evaluated by immunofluorescent staining for nuclear factor κB (NF-κB) p65 and cyclooxygenase 2 (COX-2). The number of DNA double-strand breaks (DSBs) was also detected by means of phospholylated histone H2AX (γ-H2AX) focus formation assay. Cs-BMP exposure significantly increased NF-κB p65 and COX-2 expressions, which were related to the number of γ-H2AX foci in the cell nuclei. Compared to the uniform (external) exposure to 137Cs γ-rays, NF-κB tended to be more activated in the cells proximal to the Cs-BMP, while both NF-κB p65 and COX-2 were significantly activated in the distal cells. Experiments with chemical inhibitors for NF-κB p65 and COX-2 suggested the involvement of such inflammatory responses both in the reduced radiosensitivity of the cells proximal to Cs-BMP and the enhanced radiosensitivity of the cells distal from Cs-BMP. The data show that local exposure to Cs-BMP leads to biological effects modified by the NF-κB pathway, suggesting that the radiation risk for Cs-BMP exposure can differ from that estimated based on conventional uniform exposure to normal tissues.
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Affiliation(s)
- Yusuke Matsuya
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai 319-1195, Ibaraki, Japan;
- Correspondence:
| | - Nobuyuki Hamada
- Radiation Safety Unit, Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwado-kita, Komae 201-8511, Tokyo, Japan;
| | - Yoshie Yachi
- Graduate School of Health Sciences, Hokkaido University, Kita-12 Nishi-8, Kita-ku, Sapporo 060-0812, Hokkaido, Japan;
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), 790-1 Otsuka, Motooka Tomioka, Futaba 979-1151, Fukushima, Japan;
| | - Masayori Ishikawa
- Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-8, Kita-ku, Sapporo 060-0812, Hokkaido, Japan; (M.I.); (H.D.)
| | - Hiroyuki Date
- Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-8, Kita-ku, Sapporo 060-0812, Hokkaido, Japan; (M.I.); (H.D.)
| | - Tatsuhiko Sato
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai 319-1195, Ibaraki, Japan;
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Hagiwara H, Funaki H, Shiribiki N, Kanno M, Sanada Y. Characterization of radiocesium-bearing microparticles with different morphologies in soil around the Fukushima Daiichi nuclear power plant. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-021-08061-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Ohnishi S, Thornton B, Koike T, Odano N, Asami M, Kamada S, Nagano K, Ura T. Analysis of radioactive cesium-enriched particles and measurement of their distribution in marine sediment near Fukushima Daiichi nuclear power plant. J NUCL SCI TECHNOL 2021. [DOI: 10.1080/00223131.2021.1879688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Seiki Ohnishi
- Department of Marine Risk Assessment, National Maritime Research Institute, Mitaka, Tokyo, Japan
| | - Blair Thornton
- Department of Mechanical and Biofunctional Systems, Institute of Industrial Science, the University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Toshikazu Koike
- Ship & Ocean Project Headquarters, Mitsui Engineering & Shipbuilding Co. Ltd, Akishima, Tokyo, Japan
| | - Naoteru Odano
- Department of Marine Risk Assessment, National Maritime Research Institute, Mitaka, Tokyo, Japan
| | - Mitsufumi Asami
- Department of Marine Risk Assessment, National Maritime Research Institute, Mitaka, Tokyo, Japan
| | - So Kamada
- Department of Marine Risk Assessment, National Maritime Research Institute, Mitaka, Tokyo, Japan
| | - Kazunori Nagano
- Department of Mechanical and Biofunctional Systems, Institute of Industrial Science, the University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Tamaki Ura
- Department of Mechanical and Biofunctional Systems, Institute of Industrial Science, the University of Tokyo, Meguro-ku, Tokyo, Japan
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20
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Miura H, Ishimaru T, Ito Y, Kurihara Y, Otosaka S, Sakaguchi A, Misumi K, Tsumune D, Kubo A, Higaki S, Kanda J, Takahashi Y. First isolation and analysis of caesium-bearing microparticles from marine samples in the Pacific coastal area near Fukushima Prefecture. Sci Rep 2021; 11:5664. [PMID: 33707572 PMCID: PMC7952385 DOI: 10.1038/s41598-021-85085-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/19/2021] [Indexed: 11/22/2022] Open
Abstract
A part of the radiocaesium from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident was emitted as glassy, water-resistant caesium-bearing microparticles (CsMPs). Here, we isolated and investigated seven CsMPs from marine particulate matter and sediment. From the elemental composition, the 134Cs/137Cs activity ratio, and the 137Cs 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, as suggested by (i) the presence of calcium and absence of zinc and (ii) the direction of the atmospheric plume during the radionuclide emission event 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.
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Affiliation(s)
- Hikaru Miura
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba, 270-1194, Japan.
| | - Takashi Ishimaru
- Department of Ocean Sciences, Graduate Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Yukari Ito
- Department of Ocean Sciences, Graduate Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Yuichi Kurihara
- Ningyo-Toge Environmental Engineering Centre, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama, 708-0698, Japan
| | - Shigeyoshi Otosaka
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba, 277-8564, Japan
| | - Aya Sakaguchi
- Centre for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Kazuhiro Misumi
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba, 270-1194, Japan
| | - Daisuke Tsumune
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba, 270-1194, Japan
| | - Atsushi Kubo
- Department of Geosciences, Faculty of Science College of Science, Academic Institute, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Shogo Higaki
- Isotope Science Centre, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Jota Kanda
- Department of Ocean Sciences, Graduate Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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21
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Ikenoue T, Takehara M, Morooka K, Kurihara E, Takami R, Ishii N, Kudo N, Utsunomiya S. Occurrence of highly radioactive microparticles in the seafloor sediment from the pacific coast 35 km northeast of the Fukushima Daiichi nuclear power plant. CHEMOSPHERE 2021; 267:128907. [PMID: 33220981 DOI: 10.1016/j.chemosphere.2020.128907] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 11/02/2020] [Accepted: 11/05/2020] [Indexed: 06/11/2023]
Abstract
To understand the properties and significance of highly radioactive particles in the marine environment, we have examined seafloor sediment with a radioactivity of ∼1200 Bq/kg (dry weight; after decay correction to March 2011) collected 35 km northeast of the Fukushima Daiichi Nuclear Power Plant (FDNPP). Among the 697 highly radioactive particles separated from the sediment, two particles, D1-MAX and D1-MID, had a total Cs radioactivity of ∼56 and 0.67 Bq (after decay correction to March 2011), respectively. These particles were characterized with a variety of electron microscopic techniques, including transmission electron microscopy. The 134Cs/137Cs radioactivity ratio of D1-MAX, 1.04, was comparable to that calculated for Unit 2 or 3. D1-MAX consisted mainly of a Cs-rich microparticle (CsMP) with a silica glass matrix. The data clearly suggested that D1-MAX resulted from a molten core-concrete interaction during meltdowns. In contrast, D1-MID was an aggregate of plagioclase, quartz, anatase, and Fe-oxide nanoparticles as well as clay minerals, which had adsorbed soluble Cs. D1-MID was likely a terrestrial particle that had been transported by wind and/or ocean currents to a site 35 km from the FDNPP. The radioactive fractions of D1-MAX and D1-MID were 15% and 0.36%, respectively, of the total radioactivity in the bulk sediment. These highly radioactive particles have a great impact on the movement of radioactive Cs in the marine environment by carrying condensed Cs radioactivity with various colloidal and desorption properties depending on the host phase.
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Affiliation(s)
- Takahito Ikenoue
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba, Japan.
| | - Masato Takehara
- 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
| | - Eitaro Kurihara
- 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
| | - Nobuyoshi Ishii
- Biospheric Assessment for Waste Disposal Team & Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology, Anagawa 4-9-1, Inage, Chiba, Japan
| | - Natsumi Kudo
- Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba, Japan
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
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22
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Johansen MP, Anderson D, Child D, Hotchkis MAC, Tsukada H, Okuda K, Hinton TG. Differentiating Fukushima and Nagasaki plutonium from global fallout using 241Pu/ 239Pu atom ratios: Pu vs. Cs uptake and dose to biota. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:141890. [PMID: 32916482 DOI: 10.1016/j.scitotenv.2020.141890] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
Plutonium (Pu) has been released in Japan by two very different types of nuclear events - the 2011 Fukushima accident and the 1945 detonation of a Pu-core weapon at Nagasaki. Here we report on the use of Accelerator Mass Spectrometry (AMS) methods to distinguish the FDNPP-accident and Nagasaki-detonation Pu from worldwide fallout in soils and biota. The FDNPP-Pu was distinct in local environmental samples through the use of highly sensitive 241Pu/239Pu atom ratios. In contrast, other typically-used Pu measures (240Pu/239Pu atom ratios, activity concentrations) did not distinguish the FDNPP Pu from background in most 2016 environmental samples. Results indicate the accident contributed new Pu of ~0.4%-2% in the 0-5 cm soils, ~0.3%-3% in earthworms, and ~1%-10% in wild boar near the FDNPP. The uptake of Pu in the boar appears to be relatively uninfluenced by the glassy particle forms of fallout near the FDNPP, whereas the 134,137Cs uptake appears to be highly influenced. Near Nagasaki, the lasting legacy of Pu is greater with high percentages of Pu sourced from the 1945 detonation (~93% soils, ~88% earthworm, ~96% boar). The Pu at Nagasaki contrasts with that from the FDNPP in having proportionately higher 239Pu and was distinguished by both 240Pu/239Pu and 241Pu/239Pu atom ratios. However, compared with the contamination near the Chernobyl accident site, the Pu amounts at all study sites in Japan are orders of magnitude lower. The dose rates from Pu to organisms in the FDNPP and Nagasaki areas, as well as to human consumers of wild boar meat, have been only slightly elevated above background. Our data demonstrate the greater sensitivity of 241Pu/239Pu atom ratios in tracing Pu from nuclear releases and suggest that the Nagasaki-detonation Pu will be distinguishable in the environment for much longer than the FDNPP-accident Pu.
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Affiliation(s)
- Mathew P Johansen
- Australian Nuclear Science and Technology Organisation, Sydney, Australia.
| | - Donovan Anderson
- Institute of Environmental Radioactivity, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan; Symbiotic Systems Science and Technology, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan
| | - David Child
- Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | | | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan
| | - Kei Okuda
- Faculty of Human Environmental Studies, Hiroshima Shudo University, 731-3195, Hiroshima Prefecture, Asaminami-ku, Ozuka-higashi, Japan
| | - Thomas G Hinton
- Institute of Environmental Radioactivity, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan; CERAD CoE, Norwegian University of Life sciences, Faculty for Environmental Sciences and Nature Research Management, Aas, Norway
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23
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Structural and compositional characteristics of Fukushima release particulate material from Units 1 and 3 elucidates release mechanisms, accident chronology and future decommissioning strategy. Sci Rep 2020; 10:22056. [PMID: 33328563 PMCID: PMC7744541 DOI: 10.1038/s41598-020-79169-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/04/2020] [Indexed: 12/01/2022] Open
Abstract
The structural form and elemental distribution of material originating from different Fukushima Daiichi Nuclear Power Plant reactors (Units 1 and 3) is hereby examined to elucidate their contrasting release dynamics and the current in-reactor conditions to influence future decommissioning challenges. Complimentary computed X-ray absorption tomography and X-ray fluorescence data show that the two suites of Si-based material sourced from the different reactor Units have contrasting internal structure and compositional distribution. The known event and condition chronology correlate with the observed internal and external structures of the particulates examined, which suggest that Unit 1 ejecta material sustained a greater degree of melting than that likely derived from reactor Unit 3. In particular, we attribute the near-spherical shape of Unit 1 ejecta and their internal voids to there being sufficient time for surface tension to round these objects before the hot (and so relatively low viscosity) silicate melt cooled to form glass. In contrast, a more complex internal form associated with the sub-mm particulates invoked to originate from Unit 3 suggest a lower peak temperature, over a longer duration. Using volcanic analogues, we consider the structural form of this material and how it relates to its environmental particulate stability and the bulk removal of residual materials from the damaged reactors. We conclude that the brittle and angular Unit 3 particulate are more susceptible to further fragmentation and particulate generation hazard than the round, higher-strength, more homogenous Unit 1 material.
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Imamura N, Komatsu M, Hashimoto S, Fujii K, Kato H, Thiry Y, Shaw G. Vertical distributions of radiocesium in Japanese forest soils following the Fukushima Daiichi Nuclear Power Plant accident: A meta-analysis. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 225:106422. [PMID: 32980644 DOI: 10.1016/j.jenvrad.2020.106422] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/08/2020] [Accepted: 09/08/2020] [Indexed: 06/11/2023]
Abstract
This study investigated the temporal change in vertical distributions of radiocesium inventories in Japanese forest soils during the early phase (from 2011 to 2017) following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, using three simple parameters. We calculated the fraction in the organic layer (Fl/t), the migration center (Xc) and the relaxation depth (α) using 99 soil inventory data sets. Fl/t decreased significantly from 2011 to 2017 (logistic analysis, p < 0.001). In addition, Fl/t in the FDNPP zone rapidly decreased compared to that in the Chernobyl Nuclear Power Plant (ChNPP) zone from the first year to the second year. Different migration rates from organic to mineral soil layers between previous studies in the ChNPP and this study have several possible causes such as organic litter features, climate and physico-chemical forms of initial deposition. In mineral soil layers in the FDNPP zone, only Xc increased significantly with time according to generalized mixed model analysis (p < 0.01). However, Xc and α in the ChNPP zone decreased from two to five years after the accident in 1986, which shows a high 137Cs retention in the organic layer even in the fifth year after the accident. The vertical migration of 137Cs in the mineral soil layer in the FDNPP zone appears to be due to low input of 137Cs from organic to surface mineral soil layer after the second year. These results indicate that 137Cs retention capacity of the organic layer can affect the apparent vertical migration of 137Cs in the underlying mineral soil layer.
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Affiliation(s)
- Naohiro Imamura
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Shoji Hashimoto
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan; Isotope Facility for Agricultural Education and Research, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1 Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Kazumichi Fujii
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Hiroaki Kato
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-0006, Japan
| | - Yves Thiry
- Research and Development Division, National Radioactive Waste Management Agency (Andra), 1-7 Rue Jean-Monnet, 92298, Châtenary-Malabry Cedex, France
| | - George Shaw
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
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Okumura T, Yamaguchi N, Kogure T. Distinction between Radiocesium (RCs)-bearing Microparticles and RCs-sorbing Minerals Derived from the Fukushima Nuclear Accident Using Acid Treatment. CHEM LETT 2020. [DOI: 10.1246/cl.200374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-0864, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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26
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Futagami F, Soliman M, Takamiya K, Sekimoto S, Oki Y, Kubota T, Konno M, Mizuno S, Ohtsuki T. Isolation, characterization and source analysis of radiocaesium micro-particles in soil sample collected from vicinity of Fukushima Dai-ichi nuclear power plant. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 223-224:106388. [PMID: 32868095 DOI: 10.1016/j.jenvrad.2020.106388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/23/2020] [Accepted: 08/16/2020] [Indexed: 06/11/2023]
Abstract
Radioactive caesium was released during the accident of Fukushima Dai-ichi nuclear power plant (FDNPP) into the surrounding environment. In the current work, radiocaesium micro-particles (CsMPs) and radiocaesium-rich soil particles were selectively separated from soil particles as well as from each other using autoradiography-based procedure. The applied separation scheme is based on water dilution followed by drying of the soil sample prior to imaging plate autoradiography. The SEM/EDS investigation of the individual CsMPs showed that these particles have a silicate glass structure and vary in shape with a diameter less than 10 μm. For the first time, a two-stage formation mechanism was suggested for a CsMP based on shape and structure heterogeneity of its two parts. Perfect spherical core might be formed in the first stage with a remarkable lower content of Al, and relatively higher concentrations of Si and K than an outer angulated structure, which might be attached to the core sphere during a late stage. The radiocaesium-rich soil particles have bigger size than CsMPs and have a plate-like structure with cleavages inside the grains, which suggest that these particles might be a weathered biotite. The average radioactivity ratio of 134Cs/137Cs (dated March 11, 2011) in the investigated particles was found to be 1.05 ± 0.01, which confirmed that the radiocaesium in CsMPs and in the contaminated soil particles has the same source of origin, which could be unite 3 of FDNPP.
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Affiliation(s)
- Fumiya Futagami
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Mohamed Soliman
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan; Egypt Second Research Reactor, Egyptian Atomic Energy Authority, Cairo, Egypt.
| | - Koichi Takamiya
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Shun Sekimoto
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Yuichi Oki
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Takumi Kubota
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Mitsuyuki Konno
- Citizens and Environmental Affairs Department, Ken-poku Development Bureau, Fukushima Prefecture Government, Japan
| | - Satoshi Mizuno
- Nuclear Power Safety Division, Fukushima Prefecture Government, Japan
| | - Tsutomu Ohtsuki
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
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27
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Miura H, Kurihara Y, Yamamoto M, Sakaguchi A, Yamaguchi N, Sekizawa O, Nitta K, Higaki S, Tsumune D, Itai T, Takahashi Y. Characterization of two types of cesium-bearing microparticles emitted from the Fukushima accident via multiple synchrotron radiation analyses. Sci Rep 2020; 10:11421. [PMID: 32694627 PMCID: PMC7374699 DOI: 10.1038/s41598-020-68318-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/22/2020] [Indexed: 12/05/2022] Open
Abstract
A part of radiocesium emitted during the Fukushima nuclear accident was incorporated in glassy water-resistant microparticles, called Type-A particles, which are spherical with ~ 0.1 to 10 µm diameter and ~ 10-2 to 102 Bq cesium-137 (137Cs) radioactivity; they were emitted from Unit 2 or 3 of the Fukushima Daiichi Nuclear Power Plant. Meanwhile, Type-B particles, having various shapes, 50-400 µm diameter, and 101-104 Bq 137Cs radioactivity, were emitted from Unit 1. The chemical properties of these radioactive particles have been reported in detail, but previous studies investigated only a small number of particles, especially Type-B particles. We tried to understand radioactive particles systematically by analyzing a large number of particles. Micro-X-ray computed tomography combined with X-ray fluorescence analysis revealed the presence of many voids and iron-rich part within Type-B particles. The 137Cs concentration (Bq mm-3) of Type-A particles was ~ 10,000 times higher than that of Type-B particles. Among the Type-B particles, the spherical ones had higher concentration of volatile elements than the non-spherical ones. These differences suggested that Type-A particles were formed through gas condensation, whereas Type-B particles were formed through melt solidification. These findings might contribute to the safe decommissioning of reactors and environmental impact assessment.
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Affiliation(s)
- Hikaru Miura
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-shi, Chiba, 270-1194, Japan.
| | - Yuichi Kurihara
- Ningyo-Toge Environmental Engineering Center, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama, 708-0698, Japan
| | - Masayoshi Yamamoto
- Low Level Radioactivity Laboratory, Kanazawa University, Kanazawa, Ishikawa, 923-1224, Japan
| | - Aya Sakaguchi
- Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3, Kannondai, Tsukuba, Ibaraki, 305-8604, Japan
| | - Oki Sekizawa
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Kiyofumi Nitta
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Shogo Higaki
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Daisuke Tsumune
- Atmospheric and Marine Environmental Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-shi, Chiba, 270-1194, Japan
| | - Takaaki Itai
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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Hirose K. Atmospheric effects of Fukushima nuclear accident: A review from a sight of atmospheric monitoring. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 218:106240. [PMID: 32421574 DOI: 10.1016/j.jenvrad.2020.106240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 02/29/2020] [Accepted: 03/09/2020] [Indexed: 06/11/2023]
Abstract
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, which occurred in March 2011, has released large amounts of radionuclides (such as radioiodine and radiocesium) into the atmosphere, resulting in the contamination of terrestrial and marine environments. To assess radiological and environmental effects of the FDNPP-derived radionuclides, huge amounts of radioactive monitoring activities have been conducted to environmental samples. In this paper, we review results of atmospheric radioactivity monitoring for the FDNPP accident. Learning from atmospheric radioactivity monitoring of the FDNPP accident is as follows; 1. At the initial stage of accident, large spatiotemporal variability of emitted radionuclides near the FDNPP site occurred at short (less than 1 h) time scale and small (less than 10 km) space scale due to complicated emissions of radionuclides and variable flow of Fukushima radioactive plume, 2. Chemical form of FDNPP-derived radionuclides, in which a typical example is coexistence of 137Cs-bearing submicron particles and 137Cs-bearing large hot particles in the plume, is important to have better understanding of their atmospheric behaviors as do released mechanisms and their fate in environment, 3. Atmospheric effects of the FDNPP accident continue over 8 years, in which high activity levels of the FDNPP-derived 137Cs in surface air and deposition have continued at least until the end of 2018 owing to the post-accident release and resuspension because most of the FDNPP-derived 137Cs deposited on the ground surface still remains in the soil surface as a potential source of atmospheric 137Cs.
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Affiliation(s)
- Katsumi Hirose
- Department of Materials and Life Sciences, Sophia University, Tokyo, Japan.
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29
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Teng X, Li F, Lu C. Visualization of materials using the confocal laser scanning microscopy technique. Chem Soc Rev 2020; 49:2408-2425. [PMID: 32134417 DOI: 10.1039/c8cs00061a] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The development of materials science always benefits from advanced characterizations. Currently, imaging techniques are of great technological importance in both fundamental and applied research on materials. In comparison to conventional visualization methods, confocal laser scanning microscopy (CLSM) is non-invasive, with macroscale and high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in a material. Therefore, the CLSM-based visualization technique could provide direct and model-independent insight into material characterizations. This review summarizes the recent applications of CLSM in materials science. The current CLSM approaches for the visualization of surface structures, internal structures, spatial structures and reaction processes are discussed in detail. Finally, we provide our thoughts and predictions on the future development of CLSM in materials science. The purpose of this review is to guide researchers to build a suitable CLSM approach for material characterizations, and to open viable opportunities and inspirations for the development of new strategies aiming at the preparation of advanced materials. We hope that this review will be useful for a wide range of research communities of materials science, chemistry, and engineering.
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Affiliation(s)
- Xu Teng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAICAS), State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
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30
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Hara T, Takenaka C, Tomioka R. Change in the chemical form of 137Cs with age in needles of Japanese cedar. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 213:106137. [PMID: 31983446 DOI: 10.1016/j.jenvrad.2019.106137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/21/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
Radiocesium (137Cs) derived from the accident of Fukushima Dai-ichi Nuclear Power Plant remains in forests. Although a large proportion of the 137Cs in forests has been transferred to soils, the rates of transfer to soils depend on the chemical form of 137Cs, which determines the mobility of 137Cs in plant tissues and subsequently during decomposition of leaf litter. In order to understand the dynamics of 137Cs in Sugi (Japanese cedar, Cryptomeria japonica) forests, we identified the chemical forms, such as water soluble, ion-exchangeable, and residual of 137Cs, 133Cs, K, and Rb in needle-bearing Sugi branches of different ages across several years. Compared with the results for K and Rb, Cs (133Cs + 137Cs) tended to change from a water-soluble form to an immobilized form with aging of needle-bearing branch segments. In addition, it was observed that a larger proportion of the immobilized Cs were accumulated in the green outer portions of the stems through aging.
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Affiliation(s)
- Tatsuya Hara
- Graduate School of Bioagricultural Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Chisato Takenaka
- Graduate School of Bioagricultural Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| | - Rie Tomioka
- Graduate School of Bioagricultural Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
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31
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Isotopic ratios of uranium and caesium in spherical radioactive caesium-bearing microparticles derived from the Fukushima Dai-ichi Nuclear Power Plant. Sci Rep 2020; 10:3281. [PMID: 32094430 PMCID: PMC7039901 DOI: 10.1038/s41598-020-59933-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/04/2020] [Indexed: 11/08/2022] Open
Abstract
Spherical radioactive caesium (Cs)-bearing microparticles (CsMPs) were emitted during the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March, 2011. The emission source (timing) and formation process of these particles remain unclear. In this study, the isotopic ratios of uranium (235U and 238U) and caesium (133Cs, 134Cs, 135Cs, and 137Cs) isotopes in the five spherical CsMPs (ca. 2 μm in size) sampled at 50 km west of the FDNPP were determined using secondary ion mass spectrometry and laser ablation-ICPMS, respectively. Results showed that the 235U/238U ratios of CsMPs were homogeneous (1.93 ± 0.03, N = 4) and close to those estimated for the fuel cores in units 2 and 3, and that the Cs isotopic ratios of CsMP were identical to those of units 2 and 3. These results indicated that U and Cs in the spherical CsMPs originated exclusively from the fuel melt in the reactors. Based on a thorough review of literatures related to the detailed atmospheric releases of radionuclides, the flow of plumes from the FDNPP reactor units during the accident and the U and Cs isotopic ratio results in this study, we hereby suggest that the spherical CsMPs originate only from the fuel in unit 2 on the night of 14 March to the morning of 15 March. The variation range of the analysed 235U/238U isotopic ratios for the four spherical particles was extremely narrow. Thus, U may have been homogenised in the source through the formation of fuel melt, which ultimately evaporating and taken into CsMPs in the reactor and was released from the unit 2.
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32
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McGuire C, Dale P, Copplestone D, Wilson C, Tyler A. Characterising radium-226 particles from legacy contamination to support radiation dose assessments. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 212:106127. [PMID: 31885362 DOI: 10.1016/j.jenvrad.2019.106127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 11/29/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
Radioactive particles are physically discrete sources of radioactivity that have been released into the environment as a result of past emergencies, events and practices. As the release of radioactive particles is often unplanned, the source term has not been characterised, and the potential radiation doses have not been prospectively assessed. If a plausible exposure pathway exists, radioactive particles in the environment may present a hazard to the public depending on their radiological, physical and chemical characteristics. Given their physically discrete nature, standard assessment approaches such as dispersion and transfer modelling of liquid and gaseous radioactive releases, are not appropriate for radioactive particles. The challenge for national regulatory authorities is to calculate potential radiation doses from unplanned releases of radioactive particles into the environment, assess whether the doses are relevant to radiological protection and decide whether actions are required to reduce potential doses. To address this challenge, this paper presents the approach being adopted to radiologically, physically and chemically characterise Ra-226 particles from a contaminated legacy site using gamma spectrometry, optical macroscopy and SEM-EDS. The use of particle characterisation data to support radiation dose assessments is discussed and consideration is given to radioactive particles in the context of radiological protection.
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Affiliation(s)
- C McGuire
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom; Scottish Environment Protection Agency, Strathallan House, Castle Business Park, Stirling, FK9 4TZ, United Kingdom.
| | - P Dale
- Scottish Environment Protection Agency, Strathallan House, Castle Business Park, Stirling, FK9 4TZ, United Kingdom
| | - D Copplestone
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom
| | - C Wilson
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom
| | - A Tyler
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom
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33
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Ikehara R, Morooka K, Suetake M, Komiya T, Kurihara E, Takehara M, Takami R, Kino C, Horie K, Takehara M, Yamasaki S, Ohnuki T, Law GTW, Bower W, Grambow B, Ewing RC, Utsunomiya S. Abundance and distribution of radioactive cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant into the environment. CHEMOSPHERE 2020; 241:125019. [PMID: 31610456 DOI: 10.1016/j.chemosphere.2019.125019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/27/2019] [Accepted: 09/29/2019] [Indexed: 06/10/2023]
Abstract
The abundance and distribution of highly radioactive cesium-rich microparticles (CsMPs) that were released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) during the first stage of the nuclear disaster in March 2011 are described for 20 surface soils collected around the FDNPP. Based on the spatial distribution of the numbers (particles/g) and radioactive fraction (RF) of the CsMPs in surface soil, which is defined as the sum of the CsMP radioactivity (in Bq) divided by the total radioactivity (in Bq) of the soil sample, three regions of particular interest have been identified: i.) near-northwest (N-NW), ii.) far-northwest (F-NW), and iii.) southwest (SW). In these areas, the number and RF of CsMPs were determined to be 22.1-101 particles/g and 15.4-34.0%, 24.3-64.8 particles/g and 36.7-37.4%, and 0.869-8.00 particles/g and 27.6-80.2%, respectively. These distributions are consistent with the plume trajectories of material released from the FDNPP on March 14, 2011, in the late afternoon through to the late afternoon of March 15, 2011, indicating that the CsMPs formed only during this short period. Unit 3 is the most plausible source of the CsMPs at the beginning of the release based on an analysis of the sequence of release events. The lower RF values in the N-NW region indicate a larger influence from subsequent plumes that mainly consisted of soluble Cs species formed simultaneously with precipitation. The quantitative map of the distribution of CsMPs provides an important understanding of CsMP dispersion dynamics and can be used to assess risks in inhabited regions.
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Affiliation(s)
- Ryohei Ikehara
- 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
| | - Mizuki Suetake
- 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
| | - Eitaro Kurihara
- 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
| | - Ryu Takami
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Chiaki Kino
- The Institute of Applied Energy, 1-14-2 Nishi-shimbashi, Minato-ku, Tokyo, 105-0003, 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
| | - 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, The University of Helsinki, Helsinki, 00014, Finland
| | - William Bower
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, 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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34
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Okumura T, Yamaguchi N, Suga H, Takahashi Y, Segawa H, Kogure T. Reactor environment during the Fukushima nuclear accident inferred from radiocaesium-bearing microparticles. Sci Rep 2020; 10:1352. [PMID: 31992831 PMCID: PMC6987194 DOI: 10.1038/s41598-020-58464-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/15/2020] [Indexed: 11/25/2022] Open
Abstract
Radiocaesium-bearing microparticles (CsMPs), which are substantially silicate glass, were formed inside the damaged reactor and released to the environment by the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. The present study reports several valuable findings regarding their composition and structure using advanced microanalytical techniques. X-ray absorption near-edge structure of Fe L3-absorption indicated that the oxidation state of the iron dissolved in the glass matrix of the CsMPs was originally nearly divalent, suggesting that the atmosphere in which the CsMPs were formed during the accident was considerably reductive. Another major finding is that sodium, which has not been recognised as a constituent element of CsMPs thus far, is among the major elements in the glass matrix. The atomic percent of Na is higher than that of other alkali elements such as K and Cs. Furthermore, halite (NaCl) was found as an inclusion inside a CsMP. The existence of Na in CsMPs infers that seawater injected for cooling might reach the inside of the reactor before or during the formation of the CsMPs. These results are valuable to infer the environment inside the reactor during the accident and the debris materials to be removed during the decommissioning processes.
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Affiliation(s)
- Taiga Okumura
- The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-0864, Japan
| | - Hiroki Suga
- The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yoshio Takahashi
- The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hiroyo Segawa
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
| | - Toshihiro Kogure
- The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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35
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Okumura T, Yamaguchi N, Kogure T. Finding Radiocesium-bearing Microparticles More Minute than Previously Reported, Emitted by the Fukushima Nuclear Accident. CHEM LETT 2019. [DOI: 10.1246/cl.190581] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-0864, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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36
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Ohnuki T, Satou Y, Utsunomiya S. Formation of radioactive cesium microparticles originating from the Fukushima Daiichi Nuclear Power Plant accident: characteristics and perspectives. J NUCL SCI TECHNOL 2019. [DOI: 10.1080/00223131.2019.1595767] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Toshihiko Ohnuki
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), Fukushima, Japan
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), Fukushima, Japan
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37
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Suetake M, Nakano Y, Furuki G, Ikehara R, Komiya T, Kurihara E, Morooka K, Yamasaki S, Ohnuki T, Horie K, Takehara M, Law GTW, Bower W, Grambow B, Ewing RC, Utsunomiya S. Dissolution of radioactive, cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant in simulated lung fluid, pure-water, and seawater. CHEMOSPHERE 2019; 233:633-644. [PMID: 31195267 DOI: 10.1016/j.chemosphere.2019.05.248] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/25/2019] [Accepted: 05/27/2019] [Indexed: 06/09/2023]
Abstract
To understand the chemical durability of highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant in March 2011, we have, for the first time, performed systematic dissolution experiments with CsMPs isolated from Fukushima soils (one sample with 108 Bq and one sample with 57.8 Bq of 137Cs) using three types of solutions: simulated lung fluid, ultrapure water, and artificial sea water, at 25 and 37 °C for 1-63 days. The 137Cs was released rapidly within three days and then steady-state dissolution was achieved for each solution type. The steady-state 137Cs release rate at 25 °C was determined to be 4.7 × 103, 1.3 × 103, and 1. 3 × 103 Bq·m-2 s-1 for simulated lung fluid, ultrapure water, and artificial sea water, respectively. This indicates that the simulated lung fluid promotes the dissolution of CsMPs. The dissolution of CsMPs is similar to that of Si-based glass and is affected by the surface moisture conditions. In addition, the Cs release from the CsMPs is constrained by the rate-limiting dissolution of silicate matrix. Based on our results, CsMPs with ∼2 Bq, which can be potentially inhaled and deposited in the alveolar region, are completely dissolved after >35 years. Further, CsMPs could remain in the environment for several decades; as such, CsMPs are important factors contributing to the long-term impacts of radioactive Cs in the environment.
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Affiliation(s)
- Mizuki Suetake
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yuriko Nakano
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Genki Furuki
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Ryohei Ikehara
- 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
| | - Eitaro Kurihara
- 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
| | - 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
| | - 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
| | - 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
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, Finland
| | - William Bower
- Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki, 00014, 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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38
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Uptake and elemental distribution of radiosilver 108mAg and radiocesium 137Cs in shiitake mushrooms (Lentinula edodes). J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06778-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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39
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Igarashi Y, Kogure T, Kurihara Y, Miura H, Okumura T, Satou Y, Takahashi Y, Yamaguchi N. A review of Cs-bearing microparticles in the environment emitted by the Fukushima Dai-ichi Nuclear Power Plant accident. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 205-206:101-118. [PMID: 31125755 DOI: 10.1016/j.jenvrad.2019.04.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/21/2019] [Indexed: 06/09/2023]
Abstract
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, 134Cs/137Cs 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.
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Affiliation(s)
- Yasuhito Igarashi
- Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan; Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-chome, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka, 590-0494, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Yuichi Kurihara
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan; Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency, Tomata, Okayama, 708-0698, Japan
| | - Hikaru Miura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan; Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Abiko, Chiba, 270-1194, Japan
| | - Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic, 1151, Japan.
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
| | - Noriko Yamaguchi
- Institute for Agro-environmental Sciences, NARO, 3-1-1, Kannondai, Tsukuba, 305-8604, Japan
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40
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Igarashi J, Zheng J, Zhang Z, Ninomiya K, Satou Y, Fukuda M, Ni Y, Aono T, Shinohara A. First determination of Pu isotopes ( 239Pu, 240Pu and 241Pu) in radioactive particles derived from Fukushima Daiichi Nuclear Power Plant accident. Sci Rep 2019; 9:11807. [PMID: 31413276 PMCID: PMC6694128 DOI: 10.1038/s41598-019-48210-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/25/2019] [Indexed: 11/13/2022] Open
Abstract
Radioactive particles were released into the environment during the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Many studies have been conducted to elucidate the chemical composition of released radioactive particles in order to understand their formation process. However, whether radioactive particles contain nuclear fuel radionuclides remains to be investigated. Here, we report the first determination of Pu isotopes in radioactive particles. To determine the Pu isotopes (239Pu, 240Pu and 241Pu) in radioactive particles derived from the FDNPP accident which were free from the influence of global fallout, radiochemical analysis and inductively coupled plasma-mass spectrometry measurements were conducted. Radioactive particles derived from unit 1 and unit 2 or 3 were analyzed. For the radioactive particles derived from unit 1, activities of 239+240Pu and 241Pu were (1.70–7.06) × 10−5 Bq and (4.10–8.10) × 10−3 Bq, respectively and atom ratios of 240Pu/239Pu and 241Pu/239Pu were 0.330–0.415 and 0.162–0.178, respectively. These ratios were consistent with the simulation results from ORIGEN code and measurements from various environmental samples. In contrast, Pu was not detected in the radioactive particles derived from unit 2 or 3. The difference in Pu contents is clear evidence towards different formation processes of radioactive particles, and detailed formation processes can be investigated from Pu analysis.
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Affiliation(s)
- Junya Igarashi
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.
| | - Jian Zheng
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan.
| | - Zijian Zhang
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Kazuhiko Ninomiya
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency, 790-1 Otsuka, Motooka, Tomioka, Futaba, Fukushima, 979-1151, Japan
| | - Miho Fukuda
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan
| | - Youyi Ni
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan.,State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing, 100871, China
| | - Tatsuo Aono
- Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan
| | - Atsushi Shinohara
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
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41
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Martin PG, Louvel M, Cipiccia S, Jones CP, Batey DJ, Hallam KR, Yang IAX, Satou Y, Rau C, Mosselmans JFW, Richards DA, Scott TB. Provenance of uranium particulate contained within Fukushima Daiichi Nuclear Power Plant Unit 1 ejecta material. Nat Commun 2019; 10:2801. [PMID: 31243294 PMCID: PMC6594968 DOI: 10.1038/s41467-019-10937-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 06/11/2019] [Indexed: 11/09/2022] Open
Abstract
Here we report the results of multiple analytical techniques on sub-mm particulate material derived from Unit 1 of the Fukushima Daiichi Nuclear Power Plant to provide a better understanding of the events that occurred and the environmental legacy. Through combined x-ray fluorescence and absorption contrast micro-focused x-ray tomography, entrapped U particulate are observed to exist around the exterior circumference of the highly porous Si-based particle. Further synchrotron radiation analysis of a number of these entrapped particles shows them to exist as UO2-identical to reactor fuel, with confirmation of their nuclear origin shown via mass spectrometry analysis. While unlikely to represent an environmental or health hazard, such assertions would likely change should break-up of the Si-containing bulk particle occur. However, more important to the long-term decommissioning of the reactors at the FDNPP (and environmental clean-upon), is the knowledge that core integrity of reactor Unit 1 was compromised with nuclear material existing outside of the reactors primary containment.
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Affiliation(s)
- Peter G Martin
- Interface Analysis Centre, School of Physics, HH Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK.
| | - Marion Louvel
- Department of Earth Sciences, University of Cambridge, Bullard Laboratories, Madingley Road, Cambridge, CB3 0EZ, UK
| | - Silvia Cipiccia
- Diamond Light Source, Harwell Science and Innovation Park, Didcot, OX, OX11 0DE, UK
| | - Christopher P Jones
- Interface Analysis Centre, School of Physics, HH Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
| | - Darren J Batey
- Diamond Light Source, Harwell Science and Innovation Park, Didcot, OX, OX11 0DE, UK
| | - Keith R Hallam
- Interface Analysis Centre, School of Physics, HH Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
| | - Ian A X Yang
- Interface Analysis Centre, School of Physics, HH Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency, Tomioka-Machi, Futaba-gun, Fukushima, 979-1151, Japan
| | - Christoph Rau
- Diamond Light Source, Harwell Science and Innovation Park, Didcot, OX, OX11 0DE, UK
| | - J Fred W Mosselmans
- Diamond Light Source, Harwell Science and Innovation Park, Didcot, OX, OX11 0DE, UK
| | - David A Richards
- School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK
| | - Thomas B Scott
- Interface Analysis Centre, School of Physics, HH Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
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42
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Okumura T, Yamaguchi N, Dohi T, Iijima K, Kogure T. Inner structure and inclusions in radiocesium-bearing microparticles emitted in the Fukushima Daiichi Nuclear Power Plant accident. Microscopy (Oxf) 2019; 68:234-242. [PMID: 30721986 DOI: 10.1093/jmicro/dfz004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/24/2018] [Accepted: 01/15/2019] [Indexed: 11/12/2022] Open
Abstract
Radiocesium-bearing microparticles (CsMPs), consisting substantially of silicate glass, were released to the environment during the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Since the CsMPs were formed inside the damaged reactors during the accident, we investigate the inner structures of several CsMPs by transmission electron microscopy to understand the events within the reactors. Elemental mapping of the CsMPs shows a distinct radial distribution of Cs with a higher concentration near the surface of the CsMPs, implying that Cs was in a gaseous state in the reactor atmosphere and diffused into the glass matrix after formation of the glass particles. In some CsMPs, Zn and Fe also showed a similar radial distribution to Cs, suggesting that those elements may have diffused outward where Cs was abundant. In addition, submicron crystals were present as inclusions in several of the CsMPs and were identified as chromium spinels ((Fe2+,Zn)(Cr,Fe3+)2O4), acanthite (Ag2S), molybdenite (MoS2) and hessite (Ag2Te). The spinels contained ferrous iron (Fe2+), suggesting that the atmosphere inside the reactors was reductive to some extent. Also, boron was not detected in the glass matrix of the CsMPs despite using electron energy-loss spectroscopy, indicating that most of the control rods made of B4C might have created a eutectic alloy without vaporization. These detailed investigations of the inner structures in the CsMPs may offer information on the damaged reactors that are difficult to access because of the high radiation fields.
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Affiliation(s)
- Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, Japan
| | - Terumi Dohi
- Fukushima Environmental Safety Center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, Japan
| | - Kazuki Iijima
- Fukushima Environmental Safety Center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
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43
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Zhang Z, Igarashi J, Satou Y, Ninomiya K, Sueki K, Shinohara A. Activity of 90Sr in Fallout Particles Collected in the Difficult-to-Return Zone around the Fukushima Daiichi Nuclear Power Plant. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:5868-5876. [PMID: 31034221 DOI: 10.1021/acs.est.8b06769] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released abundant radioactive particles into the surrounding environment. Herein, we analyzed the activity of 90Sr in these particles to estimate the contribution of this radionuclide to the overall radiation exposure and shed light on the processes that occurred during the accident. Seven radioactive particles were isolated from the dust and soil samples collected from areas surrounding the FDNPP, and the minimum/maximum 137Cs activities were determined as 224/4,100 Bq. Based on the size, specific activity, and 134Cs/137Cs activity ratios, we concluded that six of the seven radioactive particles were released from the Unit 1 reactor, while one particle was released from the Unit 3 reactor by a hydrogen explosion. Strontium-90 was detected in all radioactive particles, and the minimal/maximal 90Sr activities were determined as 0.046/1.4 Bq. 137Cs/90Sr activity ratios above 1000 were observed for all seven particles, that is, compared to 137Cs, 90Sr had negligible contribution to the overall radiation exposure. The 137Cs/90Sr activity ratios of the radioactive particles were similar to those of terrestrial environmental samples and were higher for particles released from the Unit 1 reactor than for samples collected from the Unit 1 reactor building, which indicates possibility of additional 90Sr-rich contamination after release of the particles.
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Affiliation(s)
- Zijian Zhang
- Graduate School of Science , Osaka University , 1-1 Machikaneyama , Toyonaka , Osaka 560-0043 , Japan
| | - Junya Igarashi
- Graduate School of Science , Osaka University , 1-1 Machikaneyama , Toyonaka , Osaka 560-0043 , Japan
| | - Yukihiko Satou
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS) , Japan Atomic Energy Agency , 790-1 Otsuka, Motooka , Tomioka , Fukushima 979-1195 , Japan
| | - Kazuhiko Ninomiya
- Graduate School of Science , Osaka University , 1-1 Machikaneyama , Toyonaka , Osaka 560-0043 , Japan
| | - Keisuke Sueki
- Center for Research in Isotopes and Environmental Dynamics (CRiED) , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8577 , Japan
| | - Atsushi Shinohara
- Graduate School of Science , Osaka University , 1-1 Machikaneyama , Toyonaka , Osaka 560-0043 , Japan
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44
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Jolin WC, Oster C, Kaminski MD. Silicate coating to prevent leaching from radiolabeled surrogate far-field fallout in aqueous environments. CHEMOSPHERE 2019; 222:106-113. [PMID: 30699369 DOI: 10.1016/j.chemosphere.2019.01.104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 01/10/2019] [Accepted: 01/20/2019] [Indexed: 06/09/2023]
Abstract
Recent characterization of radioactive particles indicate that a large percentage of the radioactivity observed during the Fukushima Daiichi nuclear meltdown was insoluble 137Cs bound within silica microparticles. Therefore, much of the decontamination research performed prior to the Fukushima incident that used either soluble radionuclides deposited onto wet surfaces or large (∼100 μm) particles characteristic of nuclear weapons fallout do not accurately represent the characteristics of potential contamination. Thus, the common practice of extrapolating radioactive decontamination methods generically to all radioactive release events is, at best, suspect. In response, a method to produce chemically-inert, radiolabeled silica particles was developed. Binding 152Eu within a sodium silicate coating required proper temperature control and ethanol was beneficial as a volatile dispersant to limit residues. In the end, a step-wise method, which first deposited 152Eu or 241Am as a nitrate salt, decomposed the salt to a sesquioxide, and finally coated the surface with sodium silicate led to dispersed particles of the desired 2 or 0.5 μm diameters. Dynamic light scattering and scanning election microscopy confirmed the particle size was unchanged. Leaching studies into several common decontaminants were performed to ensure particle inertness. Our approach allows for substitution of other radionuclides making it a robust, simple, and novel method to produce inert particle surrogates for a release event that allows direct comparison of decontamination techniques and contaminant fate studies, greatly aiding the development of response and recovery plans.
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Affiliation(s)
- William C Jolin
- Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL, USA
| | - Christopher Oster
- Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL, USA
| | - Michael D Kaminski
- Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL, USA.
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45
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Okumura T, Yamaguchi N, Dohi T, Iijima K, Kogure T. Dissolution behaviour of radiocaesium-bearing microparticles released from the Fukushima nuclear plant. Sci Rep 2019; 9:3520. [PMID: 30837619 PMCID: PMC6401112 DOI: 10.1038/s41598-019-40423-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/13/2019] [Indexed: 11/23/2022] Open
Abstract
Radiocaesium-bearing microparticles (CsMPs) composed of silicate glass were released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Since CsMPs contain a high concentration of radiocaesium, their dynamics and fate in the environment are urgent issues to be investigated. Here, we show that CsMPs are dissolved by weathering in the environment and that their radioactivity is more rapidly decreased by dissolution than the physical decay of radiocaesium. We conducted dissolution experiments with CsMPs in pure water that absorbed CO2 from the atmosphere and in artificial seawater at several temperatures. The dissolution progress was monitored by the decrease in the 137Cs radioactivity in CsMPs, and the dissolution rate was estimated. The activation energy for the dissolution of CsMPs was estimated to be 65 and 88 kJ/mol and the dissolution rate at 13 °C (approximate annual mean temperature in Fukushima City) was 0.014 and 0.140 μm/y for pure water and seawater, respectively, assuming that radiocaesium is uniformly distributed in spherical CsMPs. The shapes of the CsMPs dissolved in pure water were considerably altered, suggesting that the dissolution proceeded without maintaining the geometry. Tin oxide and iron oxide nanoparticulates formed on the surfaces. Such features were similar to those observed in CsMPs recently collected in Fukushima Prefecture, indicating that weathering dissolution of CsMPs is also occurring in the environment. For the CsMPs dissolved in seawater, a crust of secondary Mg- and Fe-rich minerals was formed, and the glass matrix inside the crust decreased, creating space between the crust and the glass matrix.
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Affiliation(s)
- Taiga Okumura
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Noriko Yamaguchi
- Institute for Agro-Environmental Sciences, NARO, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-0864, Japan
| | - Terumi Dohi
- Fukushima Environmental Safety Center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, 963-7700, Japan
| | - Kazuki Iijima
- Fukushima Environmental Safety Center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, 963-7700, Japan
| | - Toshihiro Kogure
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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46
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Morishita Y, Torii T, Usami H, Kikuchi H, Utsugi W, Takahira S. Detection of alpha particle emitters originating from nuclear fuel inside reactor building of Fukushima Daiichi Nuclear Power Plant. Sci Rep 2019; 9:581. [PMID: 30679575 PMCID: PMC6346089 DOI: 10.1038/s41598-018-36962-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 11/21/2018] [Indexed: 11/16/2022] Open
Abstract
We measured alpha emitters obtained from a reactor building in the Fukushima Daiichi Nuclear Power Plant (FDNPP) by using an alpha particle imaging detector. For developing the detector, we used a very thin (0.05-mm-thick) a cerium-doped Gd3(Ga,Al)5O12 (Ce:GAGG) scintillator and silicon photomultiplier (SiPM) arrays as the photodetector. The floor of the reactor building in FDNPP was wiped off by using smear papers, and the radioactivity of these papers was measured by the alpha particle imaging detector. In addition, we measured a Plutonium (Pu) sample (mainly 5.5 MeV alpha particles from 238Pu) obtained from a nuclear fuel facility by using of the same detector for comparison with the smear papers. The alpha spectrum was in the energy range of 5-6 MeV, which corresponds to the alpha particle energy of 238Pu (5.5 MeV). The correlation coefficient of the alpha spectra of the smear papers and the Pu sample had a strong positive linear relation. Moreover, the peak of 241Am was identified by gamma spectrum measurement. Based on these results, we report actual findings of alpha emitters in the FDNPP reactor buildings originating from nuclear fuels. The surface contamination level of alpha emitters exceeded 4 Bq/cm2.
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Affiliation(s)
- Yuki Morishita
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency, 790-1 Motooka Ohtsuka, Tomioka Town, Futaba-gun, Fukushima, 979-1151, Japan.
| | - Tatsuo Torii
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency, 790-1 Motooka Ohtsuka, Tomioka Town, Futaba-gun, Fukushima, 979-1151, Japan
| | - Hiroshi Usami
- Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency, 790-1 Motooka Ohtsuka, Tomioka Town, Futaba-gun, Fukushima, 979-1151, Japan
| | - Hiroyuki Kikuchi
- Tokyo Electric Power Company Holdings, Inc., 22 Kitahara, Ottozawa, Ohkuma-machi, Futaba-gun, Fukushima, 979-1301, Japan
| | - Wataru Utsugi
- Tokyo Electric Power Company Holdings, Inc., 22 Kitahara, Ottozawa, Ohkuma-machi, Futaba-gun, Fukushima, 979-1301, Japan
| | - Shiro Takahira
- Tokyo Electric Power Company Holdings, Inc., 22 Kitahara, Ottozawa, Ohkuma-machi, Futaba-gun, Fukushima, 979-1301, Japan
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Chen F, Hu J, Takahashi Y, Yamada M, Rahman MS, Yang G. Application of synchrotron radiation and other techniques in analysis of radioactive microparticles emitted from the Fukushima Daiichi Nuclear Power Plant accident-A review. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 196:29-39. [PMID: 30388426 DOI: 10.1016/j.jenvrad.2018.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/21/2018] [Indexed: 06/08/2023]
Abstract
During the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, large amounts of radioactive materials were released into the environment. Among them, a large proportion of the radionuclides, such as Cs, entered into the environment as radioactive microparticles (RMs). In recent years, the characterization of RMs based on synchrotron radiation (SR) techniques has been reported, since their physical and chemical properties played an important role in evaluating the chemical reactions and physical changes that occurred when the nuclear material meltdowns took place. In this review, we summarize separation and measurement technologies used in studies of RMs, and we emphasize the application of SR-based techniques in the characterization of RMs. We report research progress, including information for elemental composition, isotopic distribution, radioactivity, and formation processes. Also, we compare the RMs from the FDNPP and the Chernobyl Nuclear Power Plant accidents. The SR-based technologies offer great improvement in the resolution and precision compared to conventional technologies, such as X-ray fluorescence and X-ray diffraction.
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Affiliation(s)
- Fei Chen
- Key Laboratory of Radiological Protection and Nuclear Emergency, National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing, 100088, China
| | - Jun Hu
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masatoshi Yamada
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - M Safiur Rahman
- Atmospheric & Environmental Chemistry Lab. Chemistry Division, Atomic Energy Centre, Dhaka, 1000, Bangladesh
| | - Guosheng Yang
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan.
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Ishikawa T, Matsumoto M, Sato T, Yamaguchi I, Kai M. Internal doses from radionuclides and their health effects following the Fukushima accident. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2018; 38:1253-1268. [PMID: 30124199 DOI: 10.1088/1361-6498/aadb4c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This paper presents an overview of current internal dose estimates from the Fukushima accident, potential population specific uncertainties in these estimates are investigated, along with the relative effects of internal and external exposures. Thyroid doses were largely due to 131I, but variations in thyroid weight and fractional uptake and retention times of 131I in the thyroid contribute to uncertainties in thyroid dose estimates. Lower values for these parameters in the Japanese population, as compared to international reference assumptions, would lead to underestimation of doses on the basis of reference thyroid weights and overestimation of doses using reference thyroid uptake and retention times. Any overall bias in thyroidal doses due to population specific factors is the net result of the balance between these effects. Internal doses to other organs are largely due to 134Cs and 137Cs and their whole body distribution, population specific differences in these dose estimates are driven by average body mass, due to the inverse relationship between this and retention times. Potential differences in dose estimates and any inferred risks, due to local population specific factors, may be less than a factor of two for children and male adults, but the potential difference may be slightly underestimated for female adults. Recent micro-dosimetric studies have confirmed the existing perception that risk from internal exposures to 137Cs, 134Cs, and 131I should be nearly equivalent to that from external exposure to gamma rays at the same absorbed dose. Epidemiological studies provide comparisons between external and internal exposures to 131I in children and suggest that effects of internal exposure are similar to those of external exposure. Effective dose has been formulated to harmonise internal and external exposure risks for radiation protection purposes. On the basis of this review, the use of effective dose in this context does not seem to be unreasonable.
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Affiliation(s)
- Tetsuo Ishikawa
- Ad hoc Committee of Internal Exposure Evaluation of Japan Health Physics Society, Yoshimatsu Buid. 3F, 3-7-2 Shinbashi, Minato-ku, Tokyo, 105-0004, Japan. Fukushima Medical University, Hikarigaoka 1, Fukushima City, 960-1295, Japan
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Nakamura S, Kajimoto T, Tanaka K, Yoshida H, Maeda M, Endo S. Measurement of 90Sr radioactivity in cesium hot particles originating from the Fukushima Nuclear Power Plant Accident. JOURNAL OF RADIATION RESEARCH 2018; 59:677-684. [PMID: 30124896 PMCID: PMC6251428 DOI: 10.1093/jrr/rry063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/15/2018] [Indexed: 06/08/2023]
Abstract
A method for the determination of 134+137Cs and 90Sr in cesium hot particles (Cs-HPs) originating from the Fukushima Daiichi Nuclear Power Plant accident has been developed. The method depends on a response function that is calculated by PHITS code and fitted to the beta-ray spectrum measured with a Si-detector. The 134+137Cs radioactivity in the Cs-HPs was consistent with that measured by a Ge-detector, thus confirming the reliability of the method. The 90Sr/137Cs ratios, which ranged from 0.001 to 0.0042, were consistent with a 90Sr/137Cs inventory ratio for contaminated soil samples. That is, the extracted Cs-HPs contained 90Sr in the same ratio as that for the 90Sr/137Cs inventory ratio for the contaminated soils. The method is attractive in that the samples are unaltered, andthat no chemical separation techniques are required.
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Affiliation(s)
- Shunsuke Nakamura
- Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Japan
| | - Tsuyoshi Kajimoto
- Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Japan
| | - Kenichi Tanaka
- Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Japan
| | - Hideo Yoshida
- Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Japan
| | - Makoto Maeda
- Nature Science Center for Basic Research and Development (N-BARD), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Japan
| | - Satoru Endo
- Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Japan
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Manabe K, Matsumoto M. Development of a stochastic biokinetic method and its application to internal dose estimation for insoluble cesium-bearing particles. J NUCL SCI TECHNOL 2018. [DOI: 10.1080/00223131.2018.1523756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
| | - Masaki Matsumoto
- National Institutes for Quantum and Radiological Science and Technology, Inage-ku, Chiba-shi, Japan
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