The Large Block Tracer Test is a series of experiments to study the migration of radionuclides through fractures in rock at the scale of one meter. The separate effects to be considered are sorption onto minerals within the rock matrix; diffusion of radionuclide species through the rock matrix, diffusion and hydrodynamic dispersion within the fracture; and the effect of heterogeneity in the fluid flow field (also known as macro dispersion or channeling). The rock fractures to be used have natural fractures or artificial fractures with engineered heterogeneity. These tracer experiments will provide data with well-defined geometry and conditions for use in code validation. The experiments also provide an experimental framework to test inverse methods. Results are presented for a series of migration experiments using conservative tracers in artificial fractures with near parallel plane and near wedge-shaped fractures. The results are compared with those predicted with transport code TRACR3D. The fracture is treated as an equivalent porous medium with a ``cubic law`` permeability and a porosity that is proportional to the aperture. The results show good agreement, both between experimental results and those predicted by TRACR3D, but also between the distribution of the dye tracer in the fracture and the elution profiles. This suggests that the transport of a tracer through a fracture can be inferred from elution profiles
