Abstract
From the viewpoint of confidence building, it is very important to guarantee the quality of data for evaluating properties of the geological environment. To guarantee the quality of data, measurement with extremely well-known and repeatable precision and supporting documentation, that is able to explain the process of obtaining the data, are required.
The Japan Nuclear Cycle Development Institute (JNC) has been developing investigation techniques for deep geological environments in crystalline rock.
To date, drilling techniques and investigation equipment, such as a borehole sparker source for cross-hole seismic tomography, hydraulic test equipment and a groundwater sampler that meet the above mentioned requirements, have been developed. A hydraulic test sequence to confirm repeatability of measurement results and a groundwater sampling method to evaluate drilling fluid effects were also developed. The feasibility and usefulness of these investigation techniques were evaluated through ongoing geoscientific R&D programmes carried out in the Tono region, central Japan.
This paper is focused on techniques for groundwater investigation and describes investigation techniques developed by the JNC to evaluate hydrogeological and hydrochemical properties of rock and groundwater deep underground.
