Long Term Diffusion (LTD) Experimental Concept

The LTD project is a series of experiments which aims to obtain quantitative information on matrix diffusion in fractured rock under in situ conditions. The project plans for in situ and laboratory experiments. In addition, a natural tracer study provides information on matrix diffusion processes over geological time scales.

Archived samples, where Cs-137 has diffused in situ prior to excavation will also be studied. The in situ and laboratory-based work will be strongly linked to modelling with the overall aim of providing evidence for matrix diffusion, suitable for inclusion in performance assessments.

The combination of in situ research with laboratory investigations, combined with natural analogue and modelling data provides a robust dataset to tackle the difficult problem of quantifying matrix diffusion.