Abstract: COMPLEX REACTIONS OF DTPA WITH URANIUM，NEPTUNIUM AND PLUTONIUM ⅡSTUDY ON EXTRACTION KINETICS OF Np(Ⅳ) BY TBPDTPA SYSTEMWu Qiulin(Institute of Nuclear Energy Technology,Tsinghua University,P.O.Box 1021,Beijing 102201)Chen Shuming Li Guanghong(Beijing Institute of Nuclear Engineering,Beijing 100840)ABSTRACTThe kinetics in extraction process of Np(Ⅳ) by TBP in the presence of DTPA is investigated.The results show that the HDBP can lower the reaction rates of extracting and stripping Np(Ⅳ).But in the presence of sufficient uranium the extraction and stripping of Np(Ⅳ) become quick,as HDBP firstly reacts with uranium.So,in the practical application the reaction rates of extraction processes of Np(Ⅳ) by TBP in the presence of DTPA could not be too tow.Key words DTPA Kinetics Complex Neptunium