Structural analysis of Co-extracted heptavalent technetium and rhenium complexes by EXAFS

EXAFSによるTc(VII), Re(VII)及びMn(VII)の構造解析

鈴木 伸一; 矢板 毅; 岡本 芳浩  ; 塩飽 秀啓   ; 本橋 治彦*

Suzuki, Shinichi; Yaita, Tsuyoshi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Motohashi, Haruhiko*

TBPを用いる核燃料再処理においてテクネチウムは非常に複雑な挙動を示す。特に、U(VI),Pu(IV)やZr(IV)が系内に共存するとテクネチウムは共抽出される。この共抽出のメカニズムとしては硝酸イオンと過テクネチウムイオンとの交換によるものであり、発表においては、U-Tc共抽出錯体の構造について同属であるRe(VII)やMn(VII)と比較しながら報告する。

In spent fuel reprocessing, distribution behavior of technetium in tri- butyl phosphate (TBP) extraction system is a very complicated. Especially, in the presence of metallic ions, i.e., U(VI), Pu(IV)and Zr(IV)in the TBP extraction system, the extraction of technetium is enhanced by the co- extraction with U, Pu and Zr. The mechanism of co-extraction mechanism of technetium is performed by exchange with nitric acid ion and per-technetate ion. In this research, we perform the structural analysis of technetium complexes in ethanol solution compared with rhenium and manganese complexes by EXAFS. Furthermore we measured some organic complexes and co-extracted complexes of technetium with uranium and zirconium extracted by TBP as compared with those of rhenium.