Purex流程铀钚分离工艺中锝对镎走向的影响  

Influence of Technetium on Routing of Neptunium in U/Pu Separation Stage in Purex Process

作　　者：周贤明[1] 叶国安[1] 张虎[1] 罗方祥[1] 刘协春[1] 李丽[1] 

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413

出　　处：《原子能科学技术》2015年第2期193-199,共7页Atomic Energy Science and Technology

基　　金：国家自然科学基金资助项目(91326111)

摘　　要：在HNO3-U(Ⅳ)-N2H4-Tc(Ⅶ)-Np(Ⅴ)体系中,Np(Ⅴ)迅速还原为Np(Ⅳ)。对比研究表明,Tc是该体系中Np(Ⅴ)迅速还原的主要原因。该体系中的主要反应是U(Ⅳ)将Tc(Ⅶ)还原为Tc(Ⅳ),进而Tc(Ⅳ)将Np(Ⅴ)还原为Np(Ⅳ)。本文通过串级和台架实验研究了该体系中锝对镎走向的影响。结果表明,Np(Ⅴ)的还原速度随HNO3浓度、初始Tc浓度的增大和温度的升高而加快。在模拟Purex流程铀钚分离工艺的条件下,试管串级和微型混合澄清槽台架实验结果表明,提高1AP料液中Tc(Ⅶ)的浓度、升高反应温度,Np进入1BU中的百分含量增加。It was found that in the nitric acid solution containing U（Ⅳ）,hydrazine,Tc（Ⅶ）and Np（Ⅴ）,Np（Ⅴ）was reduced to Np（Ⅳ）quickly.The main reason of the fast reduction of Np（Ⅴ）was due to Tc（Ⅳ）,which was produced by the reduction of Tc（Ⅶ）in the presence of U（Ⅳ）.The routing of Np in U/Pu separation stage was studied by tube cascade experiments and bench scale experiments at a miniature mixingsettler set.The results show that nearly 67.7% of Np goes into 1BU in the presence of Tc in the 1AP,but approximately 27.0% of Np goes into the 1BU in the absence of Tc.The amount of Np going into 1BU increases with the reaction temperature and the concentration of Tc（Ⅶ）in 1AP.

关 键 词：铀钚分离工艺 镎走向 Tc(Ⅳ) Np(Ⅴ) 镎过程化学 

分 类 号：TL241[核科学技术—核燃料循环与材料]