被动累积式大气环境辐射监测方法研究

The environmental radiation monitoring is an integral part in the development and application of nuclear energy and technology. As the public concern to radiation risks is much stronger than before, there is an urgent need to develop more passive methods which are suitable for large-scale and long-term measurements of environmental radiation. This project is mainly aimed at the atmospheric monitoring around nuclear and radiation facilities. Based on passive detectors such as thermoluminescence and glass dosimeters, new methods for both discrimination and quantitative measurements of gamma radiation originating from nuclear and radiation facilities are going to be studied. Furthermore, based on the principles of free air diffusion and desiccant adsorption, new passive samplers with vapor absorbers are planned to be developed for collecting and monitoring the tritium in vapor form (HTO) released from nuclear facilities. The expected results of this study are not only important for the academic development of the radiation and environmental protection discipline, they also have a wide range of practical value and application prospects especially in our country in which the development of nuclear energy and radiation technology is rapid.

辐射环境监测是核能与核技术开发应用中不可或缺的基础，在全社会强烈关注放射性危险的当代，亟需深入研究适用于多地点和长时间累积测量的被动取样式环境辐射监测方法与技术。本项目主要针对核与辐射设施周边的大气环境监测，拟基于热释光或玻璃剂量计等无源探测器，研究可有效甄别并能定量评价源自于核与辐射设施微量γ辐射的累积监测新方法；针对核设施的重要气态流出物氚，基于大气自由扩散和干燥剂吸附原理，研究大气中氚化水蒸气（HTO）的被动累积取样和测量新方法。本研究的预期成果，不仅对辐射防护与环境保护学科的发展具有重要学术意义，特别是在核能与核技术开发应用迅猛发展的我国更具有实用价值和广泛的应用前景。

本项目针对我国辐射环境监测中的两个重要需求:精确的微量人工辐射测量以及多地点和长时间累积测量的大气氚测量，分别开展了相应的采样测量手段的开发与测量方法的研究。首先，本项目建立了一套从环境γ辐射中甄别源自于核与辐射设施成分并定量测量的方法。研究中，系统地探讨了热释光、光释光和玻璃剂量计三种无源探测器的主要剂量学特性，建立了甄别宇宙射线软硬成分、地表γ辐射、天空散射及核与辐射设施微量γ辐射的数学模型，基于蒙特卡罗方法优化设计了叠层屏蔽体，最终实现了基于无源探测器组合对于环境外照射各组分的甄别，并完成了对于低于10μGy的微量人工γ辐射的定量测量。其次，本项目建立了基于自由扩散和吸附的大气中氚化水蒸气（HTO）的被动累积取样和测量的方法。研究中掌握了多种干燥剂在取样盒内对水蒸气的吸附特性，基于流体力学仿真优化设计了氚化水蒸气的采集装置，新装置在不同气象条件的稳定性等关键性能参数远好于现有装置，在核电站周边的现场采样取得了很好的效果，已应用于全国范围大气氚化水采样和调查。.本项目按时顺利完成了计划书中制定的各项研究任务。其成果对辐射防护与环境保护学科的发展具有重要学术意义，为我国环境辐射监测提供了新的采样测量方法与技术，有很高的实用价值和广泛的应用前景，将有助于提高我国环境辐射监测的水平。