水利水电地下工程勘察中的放射性测试

Radiation test in underground engineering survey of hydropower projects

地下工程环境中的放射性是可能的职业危害因素之一,开展地下工程勘察期放射性测试研究应受到重视。《水利水电工程勘察技术标准》对可行性研究阶段隧洞勘察明确规定:应利用孔、洞开展放射性成分含量测试。以某水电站隧洞地下工程勘察为例,开展了现场天然放射性检测、岩石块状样天然放射性核素室内测试。测试指标有总射线及氡浓度2,26Ra(镭)2、32Th(钍)4、0K(钾)放射性比活度。对测试结果进行了分析、评判,结果表明该水电站待建地下建筑会存在氡浓度超标,将对地下工程施工带来不利影响,由此提出了对策措施。

Environmental radiation is one of the possible occupational harms, so the study of radiation test of underground engineering in survey period should be paid attention to. Using boreholes and adits to test radiation composition is one of contents in relative regulations for water conservancy project. Taking the underground tunnel survey of a hydropower station as an example, the in - situ natural radiation test and laboratory natural radiation element test of rock mass samples were carried out, and the indexes included total ray and concentration of Rn, specific radioactivity of 226Ra, 232Th and 40K. The testing results were analyzed and judged. It shows that the concentration of Rn in the underground structures that planned to be constructed at this hydro- power station would exceed the prescriptive standard, so it should bring unfavorable influence for construction of underground engineering. The reasonable, effective and feasible countermeasures are suggested.