Large-scale laboratory diffusion experiments in clay rocks

摘要: Abstract Clay formations are potential host rocks for high-level radioactive waste repositories. In clay materials, the radionuclide diffusion is main transport mechanism, thus, understanding of processes and determination parameters under conditions as similar possible to real ones, critical performance assessment deep geological repository. A large-scale laboratory experiment in a large cylindrical block consolidated presented this work, trying approach conditions. experimental set-up radionuclides were mixed with obtained from drilling central hole sample, re-compacted into at approximately same density block, forming tracer “solid source”. The system, that was sealed after addition tracer, did not need additional treatment sample nor external monitoring. After time selected take place (estimated by scoping calculations), sampled obtain 3D distribution concentration. modelling allowed estimation on different geometrical planes. proposed methodology tested Opalinus Mont Terri (Switzerland) preliminary tests neutral (HTO), anionic ( 36 Cl), weakly sorbing 85 Sr) very promising results obtained. It interesting noticing such configuration could be used an “ situ ” without any modification.