铀浓缩厂铀丰度在线监测装置研制

Development of On-line Uranium Enrichment Monitor of Gaseous UF₆ for Uranium Enrichment Plant

摘要: 研制了铀浓缩厂产品端UF₆气体²³⁵U丰度在线实时监测装置。该装置由NaI（Tl）探测器、脉冲处理器、压力和温度传感器、管道阀门系统等组成，利用NaI(Tl)探测器对测量容器内气态UF₆中²³⁵U发射的特征γ射线进行测量来得到²³⁵U的量，利用传感器对气体温度、压力进行测量，根据理想气体状态方程得到UF₆气体中U的总量，从而得到²³⁵U丰度。该装置现场应用实验表明：铀丰度在线监测结果相对标准偏差小于1%，与气体质谱计测量结果相对偏差小于1%。

Abstract: An on-line enrichment monitor was developed to measure the enrichment of UF₆ flowing through the processing pipes in uranium enrichment plant. A NaI(Tl) detector was used to measure the count rates of the 185.7 keV γ-ray emitted from ²³⁵U, and the total quantity of uranium was determined from thermodynamic characteristics of gaseous uranium hexafluoride. The results show that the maximum relative standard deviation is less than 1% when the measurement time is 120 s or more and the pressure is more than 2 kPa in the measurement chamber. Uranium enrichment of gaseous uranium hexafluoride in the output end of cascade can be monitored continuously by using the device. It should be effective for nuclear materials accountability verifications and materials balance verification at uranium enrichment plant.