Development of New Solvent Extraction System for Nuclear Fuel Reprocessing

本研究旨在开发一种高效的超铀元素萃取体系。由于四价和六价锕系元素可通过多种萃取剂从硝酸溶液中萃取出来，因此，关于后处理或废物处理的研究集中于开发一种有效的三价锕系元素和五价镎萃取系统。本研究中对文献的批判性调查表明，酸性或中性（双齿）有机磷化合物是迄今为止较好的三价锕系元素萃取剂。在此评价之后，二异癸基磷酸，这是一种酸性有机磷化合物，成功地应用于提取高放废液中的镎。另一方面，利用几种新合成的酰基吡唑啉酮衍生物，研究了螯合剂在废物处理中的应用。虽然这些衍生物显示出比其他螯合萃取剂更好的Am（III）和Np（V）萃取，但它们不足以有效地从高酸性废液中萃取锕系元素。

This research has been conducted to develop an efficient extraction system for transuranium elements. Since tetra- and hexavalent actinoids are readily extractable from nitric acid solutions by a number of extractants, the studies on reprocessing or waste processing have focused on the development of an efficient extraction system for trivalent actinoids and pentavalent neptunium. Critical survey of literatures conducted in this research showed that acidic or neutral (bidentate) organophosphorus compounds are so far better extractants for trivalent actinoids. Following this evaluation, diisodecyl phosphoric acid, which is one of the acidic organophosphorus compounds, were successfully applied to extract neptunium from high-level radioactive waste solutions. On the other hand, the possibility of using chelating agents in waste processing was examined with using several newly synthesized acylpyrazolone derivatives. Although these derivatives showed better extraction of Am(III) and Np(V) than other chelating extractants, they were not effective enough to extract actinoids from highly acidic waste solutions.