车载放射性废物体在线监测结果的不确定度评定

Evaluation of Uncertainty for the On-Site Monitoring Results of Carborne Radioactive Waste Container

基于BECK公式建立了车载放射性废物体在线监测模型,其复杂的测量公式使得公式的求导、各影响因素之间的相关系数难以采用解析计算方法实现,导致利用不确定度传播定律进行不确定度评定存在困难。应用蒙特卡罗不确定度合成方法评价了车载放射性废物体在线监测结果的不确定度,解决了就地γ能谱测量中的不确定度评定问题。其评定流程是首先采用A、B类不确定度评定方法评价各测量参数的不确定度,然后使用蒙特卡罗不确定度合成方法对不确定度分项进行合成。结果表明,241Am测量结果的不确定度<40%(1σ),137Cs、60Co和152Eu测量结果不确定度<34%(1σ)。

The onsite monitoring model for the carborne radioactive waste container was established.However,the formula derivative and the correlation coefficients between influence factors were difficultly calculated through analytical method because of the complexity of formula,so the evaluation of uncertainty was difficult based on the transfer law of uncertainty.The uncertainties for the monitoring results of carborne radioactive waste container were evaluated by the Monte Carlo synthesis method,and this method resolve the problem of the uncertainty assessment for the In-situ γ measurement.The processes of evaluation were that uncertainties of the parameters were completed with A and B species method,then the combine uncertainties were obtained with Monte Carlo synthesis method.The results indicated that the relative uncertainty was less than 40%（1σ） for 241Am,34%（1σ） for 137Cs,60Co and 152Eu.