铀材料中杂质钍的^(230)Th/^(232)Th比值指纹分析研究  

Fingerprinting of^(230)Th/^(232)Th in Uranium Materials for Nuclear Forensic

作　　者：徐江[1] 汪伟 席瑞阳 粟永阳[1] 王文亮[1] 李志明[1] 翟利华[1] 方随 张海涛[1] 凡金龙[1] 王玉凤 XU Jiang;WANG Wei;XI Rui-Yang;SU Yong-Yang;WANG Wen-Liang;LI Zhi-Ming;ZHAI Li-Hua;FANG Sui;ZHANG Hai-Tao;FAN Jing-Long;WANG Yu-Feng(Northwest Institute of Nuclear Technology,Xi′an 710024,China)

机构地区：[1]西北核技术研究所,西安710024

出　　处：《分析化学》2022年第2期310-316,共7页Chinese Journal of Analytical Chemistry

基　　金：科技部重大仪器专项项目(No.2012YQ250003)资助。

摘　　要：研究了铀材料中杂质钍的^(230)Th/^(232)Th比值的核取证学属性,采用基于磷酸三丁酯(TBP)的铀钍分离流程制备低本底钍纯化液,通过铀外标校正钍的分馏效应,采用多接收电感耦合等离子体质谱(MC-ICP-MS)测定^(230)Th/^(232)Th比值。结果表明,^(230)Th/^(232)Th比值是具有时效性的铀材料特征指纹信息,流程本底引入的232 Th浓度小于5.5×10-11 g/g,二氧化铀芯块、黄饼YC1、平行样黄饼YC2和黄饼YC3中的^(230)Th/^(232)Th比值分别为0.479±0.037、1.376×10^(-4)±4.8×10^(-6)、2.8582×10^(-3)±2.2×10^(-6)和2.8605×10^(-3)±2.1×10^(-6)(k=2),不确定度的主要来源是流程本底、待测样品中钍浓度,以及弱信号测量的不确定度。本方法结果准确,精密度较高,可鉴别^(230)Th/^(232)Th比值存在一定差异的铀材料,为核取证提供技术支持。Determination of thorium isotopic ratio^(230)Th/^(232)Th in uranium materials by multiple collector inductively coupled plasma mass spectrometry(MC-ICP-MS)was presented for nuclear forensic.One piece of UO 2 formed uranium pellet and three kinds of yellow cake powder were dissolved with ultrapure HNO 3(7.5 mol/L).Thorium was purified for analysis using a single column prepared with TBP resin bed,with which the sample was loaded and then Th was eluted with 4 mol/L HCl.Analyses were performed on Nu Plasma MC-ICP-MS and mass-bias correction were applied to the^(230)Th/^(232)Th using bracketing measurements of U standard.An equation was proposed to correct the contribution from Th blank for calculating the^(230)Th/^(232)Th of the uranium materials.The results showed that the^(230)Th/^(232)Th ratios of the uranium pellet,yellow cake powder named YC1,yellow cake powder named YC2 and yellow cake powder named YC3 were(0.479±0.037),(1.376×10^(-4)±4.8×10^(-6)),(2.8582×10^(-3)±2.2×10^(-6))and(2.8605×10^(-3)±2.1×10^(-6))(k=2),respectively.The determined^(230)Th/^(232)Th ratio of the uranium pellet agreed with the reference value.The yellow cake powder named YC2 and the yellow cake powder named YC3 were from the same source,whose^(230)Th/^(232)Th ratios agreed with each other and differed distinctly from that of another sourced yellow cake powder named YC1.It was proved that the thorium isotope ratio^(230)Th/^(232)Th was a newly discovered and time correlated fingerprint of uranium materials.

关 键 词：铀材料 指纹特征 ^(230)Th/^(232)Th比值 多接收电感耦合等离子体质谱 

分 类 号：O657.63[理学—分析化学] TL21[理学—化学]