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Tanaka M, Iwata C, Nakada M, Kato A, Akata N. LEVELS OF ATMOSPHERIC TRITIUM IN THE SITE OF FUSION TEST FACILITY. RADIATION PROTECTION DOSIMETRY 2022; 198:1084-1089. [PMID: 36083758 DOI: 10.1093/rpd/ncac059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 06/15/2023]
Abstract
In the deuterium plasma experiment using Large Helical Device at the National Institute for Fusion Science (NIFS), a small amount of tritium is produced by the D-D fusion reaction. Then, a part of produced tritium is discharged into the environment via a stack. Thus, the atmospheric tritium in the site of NIFS has been monitored before starting the deuterium plasma experiment. The atmospheric tritium concentrations at NIFS were indicated to be background levels in Japan. To investigate the impact of tritium discharged from the stack, the correlation between the atmospheric tritium concentration and the tritium concentration observed in the stack was evaluated, and no significant correlation was found. In addition, the atmospheric tritium concentration at NIFS ranged within the background levels in Japan. Therefore, the impact of discharged tritium from the stack would be negligible in the environment at NIFS.
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Affiliation(s)
- Masahiro Tanaka
- Departament of Helical Plasma Research, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, Japan
| | - Chie Iwata
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, Japan
| | - Miki Nakada
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, Japan
| | - Akemi Kato
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, Japan
| | - Naofumi Akata
- Department of Radiochemistry and Radioecology, Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki, Aomori, Japan
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Akata N, Iwata C, Nakada M, Kato A, Okada K, Kuwata H, Nakasone S, Tanaka M. TRITIUM CONCENTRATION IN MONTHLY PRECIPITATION NEAR THE FUSION TEST FACILITY IN JAPAN BEFORE AND AFTER THE DEUTERIUM PLASMA EXPERIMENT. RADIATION PROTECTION DOSIMETRY 2022; 198:976-984. [PMID: 36083739 DOI: 10.1093/rpd/ncac024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 06/15/2023]
Abstract
In Japan, the deuterium plasma experiment using the Large Helical Device was started at the National Institute for Fusion Science (NIFS) in March 2017 to investigate high-temperature plasma physics and hydrogen isotope effects in research leading towards the realisation of fusion energy. The deuterium plasma experiment produces small amount of tritium by fusion reactions. To understand any impacts by the experiment to the surrounding environment, monthly precipitation samples have been collected at the NIFS site since November 2013 to assess the relationship between isotope composition and chemical species in precipitation including tritium. By comparing data before and after the deuterium plasma experiment start, it was found that tritium released from the main stack of the fusion test facility had no impact on the environment surrounding NIFS.
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Affiliation(s)
- Naofumi Akata
- Institute of Radiation Emergency and Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Chie Iwata
- National Institute for Fusion Science, National Institute of Natural Sciences, 322-6 Orishi-cho, Toki, Gifu 509-5292, Japan
| | - Miki Nakada
- National Institute for Fusion Science, National Institute of Natural Sciences, 322-6 Orishi-cho, Toki, Gifu 509-5292, Japan
| | - Akemi Kato
- National Institute for Fusion Science, National Institute of Natural Sciences, 322-6 Orishi-cho, Toki, Gifu 509-5292, Japan
| | - Kazusa Okada
- Hirosaki University School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Haruka Kuwata
- Institute of Radiation Emergency and Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Shunya Nakasone
- Graduate School of Engineering and Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa 903-0213, Japan
| | - Masahiro Tanaka
- National Institute for Fusion Science, National Institute of Natural Sciences, 322-6 Orishi-cho, Toki, Gifu 509-5292, Japan
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Investigation of atmospheric tritiated water vapor level around the Fukushima Daiichi nuclear power plant. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112556] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Akata N, Tanaka M, Iwata C, Kato A, Nakada M, Kovács T, Kakiuchi H. Isotope Composition and Chemical Species of Monthly Precipitation Collected at the Site of a Fusion Test Facility in Japan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E3883. [PMID: 31614963 PMCID: PMC6843846 DOI: 10.3390/ijerph16203883] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/08/2019] [Accepted: 10/09/2019] [Indexed: 11/16/2022]
Abstract
The deuterium plasma experiment was started using the Large Helical Device (LHD) at the National Institute for Fusion Science (NIFS) in March 2017 to investigate high-temperature plasma physics and the hydrogen isotope effects towards the realization of fusion energy. In order to clarify any experimental impacts on precipitation, precipitation has been collected at the NIFS site since November 2013 as a means to assess the relationship between isotope composition and chemical species in precipitation containing tritium. The tritium concentration ranged from 0.10 to 0.61 Bq L-1 and was high in spring and low in summer. The stable isotope composition and the chemical species were unchanged before and after the deuterium plasma experiment. Additionally, the tritium concentration after starting the deuterium plasma experiment was within three sigma of the average tritium concentration before the deuterium plasma experiment. These results suggested that there was no impact by tritium on the environment surrounding the fusion test facility.
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Affiliation(s)
- Naofumi Akata
- Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki 036-8564, Japan.
| | - Masahiro Tanaka
- Department of Helical Plasma Research, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Chie Iwata
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Akemi Kato
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Miki Nakada
- Department of Engineering and Technical Services, National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Gifu, Japan.
| | - Tibor Kovács
- Institute of Radiochemistry and Radioecology, University of Pannonia, H-820010 Egyetem Str, Veszprém, Hungary.
| | - Hideki Kakiuchi
- Department of Radioecology, Institute for Environmental Sciences, Aomori 039-3212, Japan.
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