高放废物处置库甘肃北山预选区地下水的形成

Groundwater Formation in Beishan (Gansu) Preselected Area of High-Level Radioactive Waste Disposal Repository

在高放废物处置库场地选择和性能评价中,水文地质特征是最重要的因素之一,地下水的形成则是水文地质研究中的首要问题。在水文地质、地下水化学、同位素、CFC、地下水动态等资料综合分析的基础上,探讨了高放废物处置库甘肃北山预选区地下水的形成问题。研究结果表明,北山地区地下水以赋存于变质岩、岩浆岩、碎屑岩、碳酸岩节理、裂隙中的基岩裂隙潜水为主,地下水化学成分具有明显的水平分带性特征,地下水动态类型主要为入渗—蒸发—径流型,结合地下水同位素和CFC特征,认为区内地下水主要由当地大气降水入渗补给形成。浅部地下水主要由现代区内降水补给形成,而深部地下水则可能由地质历史时期降水补给形成。

In the site characterization study for high-level radioactive waste repository, the hydrogeological groundwater feature is one of the most important evaluation factors. Groundwater formation is the principal hydrogeological problem. Based on the synthetic analysis of hydrogeology, groundwater chemistry, isotopes, CFC and dynamic characteristics of water table data, the groundwater formation in Beishan preselected area of high-level radioactive waste disposal repository is discussed. The research results show that the groundwater in Beishan area is mainly phreatic water distributed in the joints and fratures of metamorphic, magmatic, clastic and carbonate rocks. The groundwater chemical components in the area possess horizontal zonation and the dynamic type mainly belongs to infiltration-evaporation-runoff type. These results in combination with groundwater isotopic and CFC data indicate that the groundwater in this area was originated mainly from the infiltration of local precipitation. The shallow groundwater is mainly recharged by modern and local precipitation, and the deep groundwater might be originated from infiltration recharge of ancient precipitation.