克量级铀中微量铕和铽的放化分离方法研究

Radiochemical Separation of Trace Europium and Terbium in Gramme Uranium

为提高中子诱发铀裂变时低产额裂变产物156 Eu和161 Tb产额测量的精度,需获得放化纯的156 Eu和161 Tb样品。本工作建立了氢氧化物共沉淀法除铝、氟化钙共沉淀法除铀、TRPO萃取法提取稀土元素、阳离子交换色谱法从混合稀土元素中分离Eu和Tb的流程,可用于大量铀、铝和裂变产物中微量Eu和Tb的分离。在待分离样品中含2 g铀、0.65 g铝和裂变产物的条件下,该流程对Eu、Tb的化学回收率均大于80%,对U、239 Np、95 Zr、103 Ru、131 I、132 Te、140 Ba、140 La、141 Ce、147 Nd等主要干扰物质的去污因子达到106。该方法可满足中子诱发铀裂变时156 Eu和161 Tb产额精确测量的要求。

In order to improve the accuracy of the fission yields of 156 Eu and 161 Tb in neutron-induced uranium fission,radiochemical purity sample of 156 Eu and 161 Tb has to be obtained.A separation procedure of Eu and Tb from uranium,aluminum and fission products was established in this paper.Aluminum was first removed by hydroxide co-precipitation method,then uranium was removed by calcium fluoride co-precipitation method,and rare earth elements were recovered by 30%TRPO-kerosene extraction method,Eu and Tb were separated from the mixed rare earth elements by cation exchange chromatography method.When the sample contains 2 g uranium,0.65 g aluminum and fission products,the chemical recoveries of Eu and Tb are better than 80%,the decontamination factors are greater than 106 for U,239 Np,95 Zr,103 Ru,131 I,132 Te,140 Ba,140 La,141 Ce and 147 Nd.The method can meet the requirement of measurement of 156 Eu and 161 Tb yield in neutron-induced uranium fission.