电位滴定法测定基准U_3O_8中铀的不确定度评定  

Uncertainty Evaluation for Determination of Total Uranium in Primary Reference Material U_3O_8 by Potentiometric Titration

作　　者：吴青龙[1] 卞敏[1] 李英秋[1] 柏云[1] 

机构地区：[1]中国工程物理研究院,四川绵阳621900

出　　处：《核化学与放射化学》2015年第2期84-88,共5页Journal of Nuclear and Radiochemistry

摘　　要：分析了电位滴定法测定基准U3O8中铀总量的检测过程,建立了测量过程分量的数学模型,讨论和比较了检测过程中各种不确定度因素,发现各不确定度因素中称样量的不确定度贡献最大,其次是测量重复性和消耗重铬酸钾质量的不确定度,K2Cr2O7相对分子质量和U的相对原子质量对不确定度结果的影响可忽略。结果表明,采用电位滴定法测定基准U3O8中铀总量,当样品中铀的总量为84.795%时,扩展不确定度为0.022%(k=2)。The determination of total uranium in primary reference material U3O8 by potentiometric titration method was discussed.A mathematical model of measurement component was established to compare the uncertainty factors during measurement process.It was found that the uncertainty of quantity of samples has maximal contribution,the uncertainties of measurement repeatability and quantity of consumed potassium dichromate are in the second place,and the effect of K2Cr2O7 relative molecular mass and U relative atomic mass to the final uncertainty factors is minimum.The results show that,when potentiometric titration method is used to determine total uranium in U3O8,an expanded uncertainty of0.022%（k=2）is recorded at total uranium of 84.795%.

关 键 词：不确定度评定 基准U3O8 电位滴定法 铀总量 

分 类 号：TL271.3[核科学技术—核燃料循环与材料]