克量级铀中微量铕和铽的放化分离方法研究

为提高中子诱发铀裂变时低产额裂变产物¹⁵⁶Eu和¹⁶¹Tb产额测量的精度，需获得放化纯的¹⁵⁶Eu和¹⁶¹Tb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、²³⁹Np、⁹⁵Zr、¹⁰³Ru、¹³¹I、¹³²Te、¹⁴⁰Ba、¹⁴⁰La、¹⁴¹Ce、¹⁴⁷Nd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¹⁵⁶Eu和¹⁶¹Tb产额精确测量的要求。

Radiochemical Separation of Trace Europium and Terbium in Gramme Uranium

In order to improve the accuracy of the fission yields of¹⁵⁶Eu and¹⁶¹Tb in neutron-induced uranium fission, radiochemical purity sample of¹⁵⁶Eu and¹⁶¹Tb 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, ²³⁹Np, ⁹⁵Zr, ¹⁰³Ru, ¹³¹I, ¹³²Te, ¹⁴⁰Ba, ¹⁴⁰La, ¹⁴¹Ce and ¹⁴⁷Nd. The method can meet the requirement of measurement of¹⁵⁶Eu and¹⁶¹Tb yield in neutron-induced uranium fission.