報告書番号

U00031

タイトル（和文）

ｴﾁﾚﾝｼﾞｱﾐﾝ四酢酸と結合したｺﾊﾞﾙﾄのｾﾒﾝﾄとﾛｰﾑへの吸着特性

タイトル（英文）

The adsorption characteristics of Cobalt combined with Ethylene-diamine-tetraacetic Acid on cement and loam

概要 （図表や脚注は「報告書全文」に掲載しております）

EDTAと結合した放射性核種の処分環境下での存在形態とその吸着挙動を明らかにするため、原子炉内で発生する代表的な放射性核種の一つであるCo-60を対象とし、Co-60の代わりに安定CoをEDTAに結合させた化合物を用い、ポルトランドセメントとロームへの60日間、20℃条件下での吸着実験を行い、以下の結論を得た。(1)EDTAと結合したCoの分配係数は、Co単体の分配係数より低くなり、Coの吸着がEDTAにより阻害されることが確認された。(2)好気的条件下でEDTAと結合したCoの分配係数は、嫌気的条件下より高いことが確認された.これは、好気的ならびに嫌気的条件下でのCoの吸着メカニズムの違いを示唆している。(3)EDTAと結合したCoのセメントおよびロームの分配係数の間には有意な違いは認められなかった。

概要 （英文）

Ethylene-diamine-tetraacetic-acid(EDTA) which is strongly complexed with various metals is used as a synthetic organic chelating agent. The purpose of this study is to clarify the characteristics of EDTA-radionuclide compound and its adsorption on various sorbents. The batch adsorption experiments were carried out under aerobic and anaerobic conditions. Radioactive cobalt(Co-60) is one of the representatives of corrosion products in nuclear power reactors. Instead of using Co-60, the EDTA combined with stable Co was adopted in this study. Ordinary Portland cement and loam were used as the sorbents for the batch adsorption experiments. During the period of two months, cement and loam were approximately incubated at 20℃ in the solution which contains only EDTA combined with Co. The following conclusions were obtained.(1)The distribution coefficient of Co combined with EDTA on cement and loam was less than that of Co only. According to the above, it was identified that the Co adsorption on cement and loam has undergone inhibition by EDTA. (2)It was identified that the distribution coefficient of Co combined with EDTA on cement and loam under aerobic conditions, respectively, was usually larger than that of Co combined with EDTA under anaerobic conditions. The above tendency suggests the difference of adsorption mechanism of Co between aerobic and anaerobic condition. (3)The significant difference between the distribution coefficient of Co combined with EDTA on cement and loam could not be regarded.

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