Solvent extraction and release behavior of ruthenium and europium in fire accident conditions in reprocessing plants (Contract research)

Amano, Yuki; Watanabe, Koji; Masaki, Tomoo; Tashiro, Shinsuke; Abe, Hitoshi

JAEA-Technology 2016-012, 21 Pages, 2016/06

JAEA-Technology-2016-012.pdf:1.81MB

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.

Size selective extraction of -tetraoctyl-diglycolamide and the structure of its divalent metal complex

Sasaki, Yuji; Masaki, Tomoo*; Saeki, Morihisa

Chemistry Letters, 36(4), p.488 - 489, 2007/04

https://doi.org/10.1246/cl.2007.488

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).

Study on release behavior of volatile ruthenium species with thermal decomposition of ruthenium(III) nitrosyl nitrate

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.