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Horie, Hiroki*; Yukumatsu, Kazuki*; Mishima, Fumihito*; Akiyama, Yoko*; Nishijima, Shigehiro*; Sekiyama, Tomio*; Mitsui, Seiichiro; Kato, Mitsugu
Journal of Physics; Conference Series, 871, p.012102_1 - 012102_7, 2017/07
Times Cited Count：1 Percentile：49.63(Physics, Applied)Mitsui, Seiichiro; Sekiyama, Tomio; Kato, Mitsugu; Asazuma, Shinichiro; Kato, Hiroyasu*; Ueta, Shinzo*
no journal, ,
A huge volume of contaminated soils and wastes has been generated by off-site decontamination works in Fukushima and has been stored at temporary storage sites located near or at decontamination sites. The soils and wastes will be sequentially transferred to the Interim Storage Facility (ISF). According to a relevant law, the soils and wastes will be disposed at a final disposal site outside Fukushima within the next 30 years. The total volume of the contaminated soils which will be stored in the ISF is estimated to be up to 20 million cubic meters, thus reduction of its final disposal volume is vital to minimize various impacts of final disposal. In order to optimize final disposal outside Fukushima, the government will commence research and development on soil treatment techniques and use application of less-contaminated soil. As the one and only institution dedicated to the comprehensive R&D of nuclear energy-related technology in Japan, we will support the government efforts.
Akiyama, Yoko*; Yukumatsu, Kazuki*; Horie, Hiroki*; Mishima, Fumihito*; Sekiyama, Tomio; Mitsui, Seiichiro; Kato, Mitsugu; Nishijima, Shigehiro*
no journal, ,
A large amount of the contaminated soil has been removed in the process of off-site decontamination works in Fukushima prefecture and will be stored intensively at the interim storage facilities (ISF). According to the amended JESCO Law, the National Government shall take necessary measures for the final disposal outside Fukushima within 30 years from the start of the ISF. In order to optimize final disposal of the contaminated soil outside Fukushima, development of effective treatment techniques is indispensable. In this study, we have been investigating selective separation of paramagnetic 2:1 type clay minerals, which strongly absorb and fix Cs ions, by superconducting magnetic separation on silt/clay suspension as a separation technique. We conducted magnetic separation experiments of contaminated soil in Fukushima utilizing a superconducting magnet based on results of particle trajectory simulation for various particle size.
Nishijima, Shigehiro*; Yukumatsu, Kazuki*; Horie, Hiroki*; Nomura, Naoki*; Akiyama, Yoko*; Mishima, Fumihito*; Sekiyama, Tomio; Mitsui, Seiichiro; Kato, Mitsugu
no journal, ,
The amount of Cs contaminated soil originating from decontamination work after the accident of Fukushima Dai-ichi Nuclear Power Plant is estimated as large as 20 million m
in maximum, and its volume reduction is required to optimize final disposal of the contaminated soil outside Fukushima pref. We have proposed a new method to reduce the volume of the contaminated soil by the combination of wet classification and high gradient magnetic separation (HGMS). In this study, we have been investigating selective separation of paramagnetic 2:1 type clay minerals and mica, which strongly absorb and fix Cs ions, by superconducting magnetic separation on silt/clay suspension as a volume reduction technique. We conducted magnetic separation experiments of contaminated soil in Fukushima utilizing a superconducting magnet based on results of particle trajectory simulation for various particle size.
Nishijima, Shigehiro*; Akiyama, Yoko*; Yukumatsu, Kazuki*; Horie, Hiroki*; Mishima, Fumihito*; Sekiyama, Tomio*; Mitsui, Seiichiro; Kato, Mitsugu
no journal, ,
By the Fukushima Daiichi Nuclear Power Plant accident, a large amount of soil was contaminated by radioactive Cs, and effective volume reduction techniques have been required to optimize final disposal of the contaminated soil outside Fukushima pref. We focused on the phenomenon that Cs ions are strongly adsorbed on paramagnetic 2:1 type clay minerals, and tried to separate 2:1 type clay minerals selectively by the combination of classification and magnetic separation. In this study, we conducted magnetic separation experiments of actual contaminated soil in Fukushima utilizing a superconducting magnet, based on the simulated results of 2:1 type clay minerals with each particle size. Based on the result, we proposed a new method for volume reduction of Cs contaminated soil.
Horie, Hiroki*; Akiyama, Yoko*; Mishima, Fumihito*; Nishijima, Shigehiro*; Mitsui, Seiichiro; Umezawa, Katsuhiro; Kato, Mitsugu; Okada, Takashi; Sekiyama, Tomio*
no journal, ,
A technique for volume reduction and recycle of cesium contaminated soil in combination with wet classification and high gradient magnetic separation was investigated. The magnetic separation can fractionate the fine soil particles (silt and clay) into high-dose and low-dose soil. This method utilizes the phenomenon that paramagnetic 2:1 clay strongly adsorbs cesium whereas diamagnetic 1:1 clay has low adsorption ability of cesium. One of the main issues in this technique is that the soil components are aggregated by organic matters, which prevents 2:1 type clay minerals from selective separation. In this study, pretreatment of the soil by K
CO
solution was conducted, prior to the magnetic separation, in order to disperse aggregates. As a result, further selective separation for 2:1 type clay minerals by the pretreatment was confirmed.
Nishimoto, Yuki*; Horie, Hiroki*; Akiyama, Yoko*; Nishijima, Shigehiro*; Mitsui, Seiichiro; Umezawa, Katsuhiro; Kato, Mitsugu; Okada, Takashi; Sekiyama, Tomio*
no journal, ,
By the accident of Fukushima Daiichi Nuclear Power Plant, a large amount of soil was contaminated by radioactive cesium. We developed a new physical treatment method using magnetic separation that can separate high-dose 2:1 type clay minerals from contaminated soil selectively. However, there is an issue that it is difficult to capture 2:1 type clay minerals efficiently, because clay minerals form aggregations with soil organic matter. Our previous study indicated that aggregates can be dispersed effectively by treatment of organic matter with KCO solution. The purpose of this study is to assess the effect of the organic matter treatment on efficiency improvement of magnetic separation for 2:1 type clay minerals. The result showed that the possibility of effective treatment method for the soil rich in organic matter like agricultural soil by combination of the pretreatment with KCO solution and magnetic separation.
