The reduction of Np(VI) and Np(V) by tit dihydroxyurea and its application to the U/Np separation in the PUREX process
The reduction of Np(VI) and Np(V) by tit dihydroxyurea and its application to the U/Np separation in the PUREX process
复制标题
DOI：
10.1524/ract.2010.1677
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
T. Yan;W. Zheng;C. Zuo;L. Xian;Y. Zhang;X. Bian;R. Li;Y. Di
中科院分区：
文献类型：
--
作者：
T. Yan;W. Zheng;C. Zuo;L. Xian;Y. Zhang;X. Bian;R. Li;Y. Di
摘要用分光光度法研究了二羟基脲对Np(VI)和Np(V)的还原作用。结果表明，DHU还原Np(VI)为Np(V)的速度特别快。在4℃下，当[HNO_3]=0.44M，[Dhu]=7.5×10~(-2)M时，表观速率常数为1.86 S~(-1)，而Np(V)进一步还原为Np(IV)的速度很慢，在2 h内未观察到Np(IV)。结果表明，在给定的实验条件下，DHU能将有机相中98%的Np(VI)快速反萃到水相中。随着水相中硝酸浓度的增加，反萃效率降低。反萃效率随Dhu浓度的增加而增加。模拟以DHU为反萃剂的Purex流程1B接触器，在给定的实验条件下，SFU/NP=183。这表明，在乏燃料后处理的铀/钚分离阶段，Np和Pu将相继出现。
Abstract The reduction of Np(VI) and Np(V) by Dihydroxyurea (DHU) was studied by spectrophotometry. The results show that the reduction of Np(VI) to Np(V) by DHU is particularly fast. The apparent rate constant is 1.86 s-1 at 4 °C as [HNO3]=0.44 M and [DHU]=7.5×10-2 M. While further reduction of Np(V) to Np(IV) is so slow that no Np(IV) is observed in 2 h. The reduction back-extraction behavior of Np(VI) in 30% tri-butyl phosphate/kerosene was firstly investigated under conditions of different temperature, different concentrations of DHU and HNO3 and various phase contact time, respectively. The results show that 98% of Np(VI) in the organic phase can be stripped rapidly to the aqueous phase by DHU under the given experimental conditions. As the concentration of HNO3 in the aqueous phase increases, the stripping efficiency decreases. While the stripping efficiency increases with the increase of the concentration of DHU. Simulating the 1B contactor of the PUREX process using DHU as the stripping agent, the SFU/Np equals to 183 under the given experimental conditions. It indicates that Np will follow with Pu in the U/Pu separation stage in the reprocessing of spent fuels.