Groundwater Isotope Characteristics of the Pre-selected Site of a High Level Radioactive Waste Repository in the Beishan Area,Gansu Province and Their Implications
高放废物处置库北山预选区地下水同位素组成特征及其意义

Knowledge of hydrogeological conditions is of paramount importance in the site selection of a high level radioactive waste repository since any radioactive materials released from the repository will be in varying degrees transported to the human environment or biosphere by groundwater.The Beishan area in Gansu Province,one of the important potential sites for China s high level radioactive waste repositories,is located in northwestern Gansu Province.In order to understand the hydrogeological conditions and get to know whether the area is a suitable site for a repository or not, the authors carried out an isotopic hydrogeological investigation and research in the past ten years. According to the field investigation and an analysis of the stable isotopes of hydrogen and oxygen, it is concluded that both shallow groundwater and deep droundwater are of meteoric origin. The shallow groundwater is recharged mainly by modern and local precipitation, and the deep groundwater might originate from infiltration rechage of ancient precipitation. From the tritium data of groundwater in the area, it is also thought that the shallow groundwater system is relatively open and its capability for water circulation is stronger than that of the deep groundwater system.