Geological Isolation Research and Development

IMAGE–GEOCHEM (Integrated MAss transport and GEOCHEMistry) was designed to study rock–water interaction in open systems, particularly in relation to rates of groundwater flow and rates of fluid–mineral reactions.

The experiments are conducted by using a series of 10 columns, in which rock–forming minerals or crushed rock are filled and a solution is pumped through. The variables are flow rate and temperature, and solution pH and ionic concentrations are measured as a function of time at the outlet of each column.

Groundwater flow and mass transport in crystalline rock mainly take place in open fractures and the behaviors are very complex due to the characteristics of the individual fractures and their connectivity.

In this experiment, water flow and tracer migration tests are conducted to investigate hydraulic characteristics of the fracture and to understand a mixing phenomena at the fracture intersection or simple fracuture network.

Groundwater and solutes are expected to move non–uniformly due to heterogeneity of micropore structures even in non–fractured rock.

MACRO (MAss transport Characterization in host ROck) was designed to clarify the transport mechanism in heterogeneous porous media, NaCl solute is used as a tracer and its transport behavior is observed as a function of time. Several sizes of glass beads are used in the equipment to simulate the heterogeneity of rock matrices.