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Kurikami, Hiroshi; Niizato, Tadafumi; Tsuruta, Tadahiko; Kato, Tomoko; Kitamura, Akihiro; Kanno, Mitsuhiro*; Kurosawa, Naohiro*
no journal, ,
To understand environmental fate of radioactive materials released from nuclear accidents is important for recovery measures. We have developed a compartment model including all important compartments and processes to describe environmental fate of radioactive materials and have applied to the Fukushima environment. The results showed a good agreement with field investigations.
Malins, A.; Kurikami, Hiroshi; Kitamura, Akihiro; Machida, Masahiko
no journal, ,
no abstracts in English
Shimoyama, Iwao; Honda, Mitsunori; Kogure, Toshihiro*
no journal, ,
The decontamination method has not been established for soil contaminated with radioactive Cs. We adopted weathered biotite (WB) which sorbed non-radioactive 
Cs as a model contaminated soil and applied heating treatment to the WB at 700
C under a low pressure condition of 14 Pa with NaCl-CaCl
mixed salt. X-ray fluorescence analysis showed that almost all Cs and K were removed from the sample at 700C and Ca became dominant with temperature. X-ray diffraction spectra largely changed after the heating treatment indicating some phase transition from WB. Transmission electron microscopy analysis clarified that augite was the dominant product after the heating treatment at 700C. These results suggest a model that Ca derived from the mixed-salt induced the formation of augite, and that K
and Cs were eliminated from the product as these large-size cations cannot constitute augite. Based on this model, we propose Cs free mineralization which can achieve decontamination and reuse of soil in Fukushima.
Shimada, Taro; Takai, Shizuka; Takeda, Seiji
no journal, ,
In order to recycle contaminated debris of which concentration is relatively lower in Fukushima Daiichi Nuclear Power Station, it is necessary to confirm that the mean radioactive concentration is lower than a reference value with consideration of the distribution by measurement and evaluation. We studied a method combining radiation measurement and inverse analysis to obtain the distribution of radioactivity concentration of recycled material. Plastic scintillation fiber will be applied to radiation measurement to obtain dose rates outside the container containing recycled material at many measurement points. As a result of application of 7 inverse analysis methods to typical two types of distribution, GVSPM and ML-EL methods can evaluate true values in the trials.
Taniguchi, Keisuke*; Kuramoto, Takayuki*; Onda, Yuichi*; Yoshimura, Kazuya
no journal, ,
no abstracts in English