Isotope techniques for the research of groundwater in the potential site of China's high-level waste repository

Using the isotope techniques, the groundwater origin, evolution and circula tion in the potential site of China's high-level waste repository are studi ed. The results indicate that both shallow groundwaters and deep groundwate rs in the site area are of meteoric origin. The shallow groundwaters; are m ainly recharged by modern and local precipitation, and the deep groundwater s; are originated from regional precipitation at higher elevation, or may b e from the precipitation during the geological history period with lower te mperature. Through the study we can also understand that the deep undergrou nd is a very low-permeability system where the groundwater flow-rates are v ery low.