Abstract
Limited number of research reports describing to behavior of deep groundwater with measured age is available. So, it is needed for the planning to deep repository of radioactive waste to investigate of behavior and cumulate database of residence time of deep groundwater flow system. In this paper, several geochemical dating methods such as H-3 dating method, C-14 dating method and Cl-36 dating method were applied to the groundwater sampled from several hundred meters of borehole and these geochemical residence time were estimated. The sampling of the groundwater from the surface level to the 350 m deep level below the ground surface was used by multi-packer system by step by step of the depth.
As a result, an clear difference of the trace concentration of each radioactive natural nuclides is obtained. So it indicate that the groundwater system at the site has multi layered groundwater flow.
