Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-29T07:37:36.930Z Has data issue: false hasContentIssue false

Porosities of and Diffusivities in Crystalline Rock and Fissure Coating Materials

Published online by Cambridge University Press:  25 February 2011

Kristina Skagius
Affiliation:
Department of Chemical EngineeringRoyal Institute of TechnologyS-100 44 STOCKHOLM, Sweden
Ivars Neretnieks
Affiliation:
Department of Chemical EngineeringRoyal Institute of TechnologyS-100 44 STOCKHOLM, Sweden
Get access

Abstract

The diffusion of non-sorbing species in different rock materials and fissure coating materials have been studied. The results show that the effective diffusivity of iodide in granites with fissure coating materials is of the same magnitude or higher as the effective diffusivity for iodide in granites without fissure coating material. Also the porosities of the granites with fissure coating material were higher. The effective diffusivity for iodide in rock materials without fissure coating material was determined to be from 1.i0-14 m2/s to about 7.10-13 m2/s.To simulate the stress that exists in the bedrock at large depths diffusion experiments with iodide in rock materials under mechanical stress, and electrical resistivity measurements in salt-water-saturated rock cores under stress have been started. Electrical resistivity measurements is an indirect method to determine the diffusivity.Results from some initial measurements show that the effective diffusivity is reduced to about 40 % of the value for unstressed samples at pressures of 230-280 bar. This is the expected stress at repository depths.

Type
Research Article
Copyright
Copyright © Materials Research Society 1984

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Crank, J., The Mathematics of Diffusion, 2nd ed., Oxford University Press, 1975.Google Scholar
2. Klinkenberg, L.J., Analogy between Diffusion and Electrical Conductivity in Porous Rocks, Geol. Soc. Am. Bull., 12, 1951, p. 559.Google Scholar
3. Brace, W.F., The Effect of Pressure on the Electrical Resistivity of Water-Saturated Crystalline rocks, J. Geophys. Res., 70, 1965, p. 5669.Google Scholar
4. Skagius, K., Neretnieks, I., Diffusion in Crystalline Rocks of some Sorbing and Nonsorbing Species, KBS Technical Report 82 12, 1983-03-09.Google Scholar