MOX燃料芯块中钚含量准确测定的研究

The Study on the Determination of Pu Content in MOX Fuel Pellets

MOX燃料芯块中钚含量是影响MOX燃料质量的关键技术指标,由于杂质元素种类较多,其中钚含量的测定往往受到较大的干扰,以现有的分析方法测定所得到的平行结果差异较大。为了准确测定MOX燃料芯块中的钚含量,文章提供了一种通过UTEVA树脂分离,利用控制电位库仑法准确测定MOX(铀钚混合物)燃料芯块中钚元素含量的方法。实验中,以MOX燃料芯块中杂质镅含量为监控参数,通过对比不同分离条件下测定的杂质镅含量,确定了杂质分离条件;通过对比不同浓度的硝酸羟胺还原效果,确定了UTEVA树脂柱上钚元素的还原条件;通过研究洗脱溶液、洗脱体积,确定了钚洗脱条件。综合上述实验,建立了钚元素的分离方法,在此分离方法下,应用氧化物标准物质得出了钚元素回收率为97.85%~98.62%,平均回收率为98.24%。最终,测得某MOX燃料芯块样品的钚元素含量为*.39%,6次测量结果精密度为优于0.5%。

The Pu content in MOX fuel pellets is a key index affecting the quality of MOX fuel.The determination of the Pu content is often disturbed,due to the variety of impurity elements.A method for determination of the Pu content in MOX fuel pellets was presented in the paper by using UTEVA resin separation and controlled potential coulomb method in order to accurately determine the plutonium content in MOX fuel pellets.Impurity separation conditions were ascertained through comparison of the Am content under different separation conditions.The Pu reduction condition was obtained in the UTEVA resins by comparing the reduction effect of different concentrations for HNO 3.NH 2 OH.Conditions for the elution were determined through the study on the solution for the elution and elution volume.Above all,the separation method was built.At the separation condition,the percent recovery of Pu was obtained from 97.85%to 98.62%,with an average of 98.24%.Finally,the Pu content of the MOX fuel pellet measured was*.39%,the RSD of the six times measurements were better than 0.5%.