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Kokubun, Yuji; Hosomi, Kenji; Nagaoka, Mika; Seya, Natsumi; Inoue, Kazumi; Koike, Yuko; Uchiyama, Rei; Sasaki, Kazuki; Maehara, Yushi; Matsuo, Kazuki; et al.
JAEA-Review 2024-054, 168 Pages, 2025/03
JAEA-Review-2024-054.pdf:2.73MB
The Nuclear Fuel Cycle Engineering Laboratories conducts environmental radiation monitoring around the reprocessing plant in accordance with the "Safety Regulations for Reprocessing Plant of JAEA, Part IV: Environmental Monitoring". This report summarizes the results of environmental radiation monitoring conducted during the period from April 2023 to March 2024 and the results of dose calculations for the surrounding public due to the release of radioactive materials from the plant into the atmosphere and ocean. In the results of the above environmental radiation monitoring, several items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Holdings, Inc. on April 1, 2016), which occurred in March 2011. In addition, environmental monitoring plan, analysis and measurement methods, monitoring data and their chronological change, meteorological data after statistical processing, status of radioactive waste release and evaluation results of the data over the normal range are included as appendices.
Sato, Kazuyoshi; Yaguchi, Eiji; Pitcher, C. S.*; Walker, C.*; Encheva, A.*; Kawano, Yasunori; Kusama, Yoshinori
Fusion Engineering and Design, 86(6-8), p.1264 - 1267, 2011/10
Times Cited Count：3 Percentile：24.12(Nuclear Science & Technology)no abstracts in English
Yaguchi, Masashi*; Komuro, Kosei*; Sasao, Eiji
no journal, ,
Minor amount of daughter radionuclides such as radium and radon are detected in the groundwater of the Tono area, where sandstone-type uranium deposits are embedded. Recently, lead isotopic ratios are measured for the uranium ores and two distinct different isochrons are found in the 
Pb/
Pb-
U/Pb diagram, showing that distinct radionuclides migration have not been occurred recently. In order to understand the radionuclides migration and its effect on lead isotopic ratios, simulation of radionuclides migration on the basis of transport theory are made for groundwater and ores in the Tono uranium deposits. The results on the basis of the proper assumption for the Tono area will be reported. The lead isotopic results would not be incompatible with the results of uranium series disequilibria.
Komuro, Kosei*; Yaguchi, Masashi*; Sasao, Eiji
no journal, ,
The Tono sandstone-type uranium deposits occur in the basal conglomerates of middle Miocene Toki lignite-bearing formation in the Mizunami group, which rest on the late Cretaceous granitic basement. In order to understand the age, origin, formation process, and radionuclides migration behavior of the deposits, lead isotopic compositions were measured for uranium ores and the associated sedimentary and granitic rocks. The Tono sandstone-type uranium deposits were formed by initial deposition caused by reduction of uranium in association with the decomposition of the plant materials at the time of the deposition of host conglomerates and sandstones in the Toki lignite-bearing formation, the uranium of which originated from the granitic basement. At the time of deposition of Seto group after the upheaval of this region, some parts of these ores dissolved by oxidative groundwater and the secondary ores were formed by the subsequent re-deposition by reduction.
Sato, Kazuyoshi; Kawano, Yasunori; Yaguchi, Eiji; Kusama, Yoshinori
no journal, ,
no abstracts in English
Sato, Kazuyoshi; Yaguchi, Eiji; Kawano, Yasunori; Kusama, Yoshinori
no journal, ,
no abstracts in English
