To fulfil the overall project objectives, a series of radionuclide and colloid solutions were injected into a dipole flow field. Two sequential injections of radionuclide tracer cocktails (see below). The first cocktail was injected without adding bentonite colloids and the second cocktail contains bentonite colloids.

This layout was selected in order to investigate the migration behaviour of the radionuclides in the presence and absence of bentonite colloids by comparison of the eluted concentrations of the radionuclides and colloids from the flow field. The migration/retardation behaviour of the injected radionuclides and colloids in the fracture is observed in situ by on-line analysis of the eluted groundwaters and is backed-up by additional analyses back in the laboratory.

CRR Injection layout

CRR Extraction layout

Injection cocktail table