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Amano, Yuki; Watanabe, Koji; Masaki, Tomoo; Tashiro, Shinsuke; Abe, Hitoshi
JAEA-Technology 2016-012, 21 Pages, 2016/06
To contribute to safety evaluation of fire accident in fuel reprocessing plants, solvent extraction behavior of ruthenium, which could form volatile species, was investigated. Distribution ratios of ruthenium at fire accident conditions were obtained by extraction experiments with several solvent composition at different temperature as parameters. In order to investigate release behavior of ruthenium and europium at fire accident, release ratios of ruthenium and europium were also obtained by solvent combustion experiments.
Abe, Hitoshi; Masaki, Tomoo; Amano, Yuki; Uchiyama, Gunzo
JAEA-Research 2014-022, 12 Pages, 2014/11
To contribute safety evaluation of boiling and drying accident of high active liquid waste (HALW) in fuel reprocessing plant, release behavior of Ru, which was considered as an important nuclide for evaluating public dose from the volatile viewpoint, has been investigated. It has been reported that release of Ru becomes conspicuously after HALW is dried up. In this work, to grasp the release behavior of Ru, release ratio of Ru with thermal decomposition of Ru nitrate, which would be in the dried HALW, was measured and release rate constant of Ru from the nitrate was estimated. It was found that the calculation result of release rate of Ru from the nitrate with rise of temperature by using the constant could well simulate the result acquired from the beaker-scale experiment.
Sasaki, Yuji; Masaki, Tomoo*; Saeki, Morihisa
Chemistry Letters, 36(4), p.488 - 489, 2007/04
Times Cited Count:10 Percentile:39.76(Chemistry, Multidisciplinary)Using the new extractant, -tetraoctyl-diglycolamide (TODGA), the dependence of the distribution ratio on the ionic radii for M(II) was investigated and their relation with the structures of metal-complexes were discussed. Ca(II) (ionic radius: 100 pm) shows the highest D values, and the D values decrease with increase and decrease of ionic radius from 100 pm. The geometrical optimization by density functional theory (DFT) of M(II)-TODGA complex suggests that the carbonyl oxygen has more affinity with metal than the ether oxygen, and the distance between the center of oxygen donor and the edge of cation corresponds to the van der Waals radius of oxygen atom. The most stable complex, as 1:1 complex, can be formed with Mg(II) from DFT calculation, the complex become unstable with increase of ionic radius of M(II). This order is good agreement with the magnitude of D for Ca(II), Sr(II) and Ba(II).
Abe, Hitoshi; Masaki, Tomoo; Watanabe, Koji; Suzuki, Shinya; Tashiro, Shinsuke; Amano, Yuki; Yamane, Yuichi; Yoshida, Kazuo; Uchiyama, Gunzo; Ueda, Yoshinori*; et al.
no journal, ,
The release and transport characteristics of radioactive materials under the boiling and desiccating accident of the high active liquid waste in a reprocessing plant have been studied. Ruthenium is one of the important nuclides for evaluating public dose from the volatile viewpoint. By using apparatus which can control the experimental condition of temperature and atmosphere composition in the gas phase, the transport characteristics data of RuO which is chemical form of Ru with volatility was acquired. As the results, it was found that RuO would transport in the gas phase without thermal decomposition and deposition onto the inner wall of glass under the experimental condition with nitric acid vapor.
Abe, Hitoshi; Masaki, Tomoo; Watanabe, Koji; Tashiro, Shinsuke; Yamane, Yuichi; Amano, Yuki; Yoshida, Kazuo; Uchiyama, Gunzo
no journal, ,
The release and transport characteristics of radioactive materials under the boiling and drying accident of the high active liquid waste (HALW) in a reprocessing plant have been studied. It has been reported that Ru, which is one of the important nuclides for evaluating public dose from the volatile viewpoint, is released mainly with progressing dryness of HALW. In this work, to grasp the release behavior of Ru, release ratio of Ru with thermal decomposition of Ru nitrate, which would be in the dried HALW, was measured and release rate constant of Ru from the nitrate was estimated. It was found that the calculation result of release rate of Ru from the nitrate with rise of temperature by using the constant could well simulate the result acquired from the beaker-scale experiment.