The nature of diffusivity and porosity in crystalline rock was studied by electrical conductivity measurements, steady-state diffusion experiments, saturation-leaching of tracers with cylindrical rock samples and analysis of the concentrations of different elements from core samples or pore water near fractures. The phenomena of main interest were dead-end porosity, ion-exclusion, sorption, and the continuity of pore networks. The modelling of experimental results was based on a modified Fick's second law for diffusion, which was solved either by analytical or numerical methods. The measured De and ε were found to statistically follow an exponential presentation: Archie's law. The existence of ion-exclusion for anions was confirmed. The connectivity of the pore network extended in the laboratory experiments at least six centimetres, in coarse-grained granite in nature several metres but in fine-grained rock samples of a uranium deposit the element mobilization effects could be seen only to the depth of 2–3 centimetres.
|Title of host publication||Symposium V – Scientific Basis for Nuclear Waste Management XVI|
|Editors||C.G. Interrante, R.T. Pabalan|
|Place of Publication||Pittsburgh|
|Publisher||Materials Research Society|
|Publication status||Published - 1992|
|MoE publication type||B3 Non-refereed article in conference proceedings|
|Series||MRS Online Proceedings |