核电厂放射性固体废物桶外γ测量重要影响因素的探讨

本文针对我国运行核电厂常用的两种桶外γ活度测量系统(整体γ射线测量系统(IGS)和分段γ射线测量系统(SGS)),阐述了桶装放射性固体废物的活度和密度分布不均匀条件下对测量系统探测效率和不确定度的影响。现场试验及蒙特卡罗模拟计算表明,桶外γ活度测量系统基本满足电厂桶装废物γ核素活度测量要求,活度分布和密度分布导致的测量结果不确定度分别在17%和20%之内;同时应正确认识桶外γ测量方法在桶装固体废物测量中的地位及作用,针对存在的问题,提出应制定废物桶活度桶外测量方法的技术规范、保证设备的工作环境和加强人员培训。

Discussion on out-of-barrel Gamma Measurement of NPP Solid Radioactive Wastes

The effect of activity and density distribution of solid radioactive waste in barrels on the detection efficiency and uncertainty of two kinds of out-of-barrel activity measurement systems, integrated gamma-ray measurement System (IGS) and segmented gamma-ray measurement system (SGS), commonly used in nuclear power plants in China is described. Field tests and Monte Carlo simulations show that the out-of-barrel gamma measurement system basically meets the requirements for activity measurement of barrelled wastes in nuclear power plants, and the uncertainty of measurement results caused by the distribution of activity and density is within 17% and 20% respectively. At the same time, the position and function of this method should be correctly understood. In view of the existing problems, it is suggested that the relevant technical specifications should be prepared, the working environment of the equipment should ensured, and the personnel training should be strengthened.