核电厂液态流出物中氚的测量方法验证

Verification of a method for measurement of tritium in liquid effluent of nuclear power plants

目的 探讨混合离子交换树脂纯化核电厂液态流出物中氚的测量方法,并实验验证方法的可行性,为核电厂液态流出物中氚的测量标准方法制定提供技术支撑。方法 通过测试混合离子交换树脂纯化样品淬灭因子、电导率、β核素吸附效率,确定混合离子交换树脂纯化效果;开展混合离子交换树脂纯化与常压蒸馏纯化2种测定氚结果的方法比对,比较不同方法测试结果的差异;重复测试不同活度浓度样品和加标样品,通过计算相对标准偏差和加标回收率验证方法的精密度和正确度。结果 该方法纯化样品淬灭因子、电导率、氚活度浓度与常压蒸馏纯化测试结果未见显著性差异;EC20MB型树脂对碳、铁、镍、锶、钇、铯等常见β核素吸附效率范围为99.28%~99.88%;同一样品重复测试多次结果相对标准偏差范围为5.2%~9.4%,加标回收率范围为86.8%~107%。结论 混合离子交换树脂纯化与常压蒸馏纯化测试结果未见显著性差异,方法精密度、正确度等满足生态环境主管部门对核动力厂液态流出物中氚的监测要求,可在日常监测工作中推广使用。

Objective To explore the method for measurement of tritium in nuclear power plant liquid effluent purified by a mixed ion-exchange resin,to verify the feasibility of the method by experiments,and to provide technical support for the development of standard methods for the measurement of tritium in liquid effluent of nuclear power plants.Methods The purification effect of the mixed ion-exchange resin was determined by measuring the quenching factor,conductivity,andβ-nuclide adsorption efficiency of the samples purified using the resin.A comparison was made between the ion-exchange resin method and the atmospheric distillation method for tritium determination.The precision and accuracy of the method were verified by calculating the relative standard deviation and the recovery in repeated measurement of samples with different activity concentrations and spiked samples.Results There were no significant differences in quenching factor,conductivity,and tritium activity concentration between the two methods.The adsorption efficiencies of EC20MB resin for commonβ-nuclides such as carbon,iron,nickel,strontium,yttrium,and cesium ranged from 99.28%to 99.88%.Repeated measurement of the same sample showed relative standard deviations of 5.2%-9.4%and recoveries of 86.8%-107%.Conclusion There were no significant differences between the results of the ion-exchange resin purification method and the atmospheric distillation method.The precision and accuracy of the method met the requirements of the ecological and environmental management authorities for monitoring tritium in liquid effluent from nuclear power plants.This method can be widely used in daily monitoring work.