Measurements of cesium and strontium diffusion in biotite gneiss

Journal Article · Fri Jan 01 00:00:00 EST 1988 · Water Resour. Res.; (United States)

DOI:https://doi.org/10.1029/WR024i001p00075· OSTI ID:6924824

Skagius, K; Neretnieks, I

A significant retardation of radionuclides transported by flowing water from an underground repository can be expected if the nuclides are able to diffuse into the water filled micropores in the rock. This diffusion into the pores will also increase the surface available to interactions between the nuclides in the ground water and the rock material, such as sorption. To calculate the retardation, it is necessary to know the sorption properties and the diffusivities in the rock matrix for the radionuclides. Diffusion experiments with cesium and strontium in biotite gneiss samples have been performed. Both the transport of strontium and cesium through rock samples and the concentration profiles of cesium and strontium inside rock samples have been determined. The result shows that diffusion of cesium and strontium occurs in the rock material. A diffusion model has been used to evaluate the diffusivity. Both pore diffusion and surface diffusion had to be included in the model to give good agreement with the experimental data. If surface diffusion is not included in the model, the effective pore diffusivity that gives the best fit to the experimental data is found to be higher than expected from earlier measurement of iodide diffusion in the same type of rock material. This indicates that the diffusion of cesium and strontium (sorbing components) in rock material is caused by both pore diffusion and surface diffusion acting in parallel.

• Research Organization: Royal Institute of Technology, Stockholm (Sweden)
• OSTI ID: 6924824
• Journal Information: Water Resour. Res.; (United States), Vol. 24:1
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CESIUM
DIFFUSION
GNEISSES
RADIONUCLIDE MIGRATION
GROUND WATER
STRONTIUM
BIOTITE
MATHEMATICAL MODELS
RADIOACTIVE WASTE DISPOSAL
ROCK-FLUID INTERACTIONS
UNDERGROUND DISPOSAL
ALKALI METALS
ALKALINE EARTH METALS
ELEMENTS
ENVIRONMENTAL TRANSPORT
HYDROGEN COMPOUNDS
MANAGEMENT
MASS TRANSFER
METALS
METAMORPHIC ROCKS
MICA
MINERALS
OXYGEN COMPOUNDS
ROCKS
SILICATE MINERALS
WASTE DISPOSAL
WASTE MANAGEMENT
WATER
520300* - Environment
Aquatic- Radioactive Materials Monitoring & Transport- (1989)
510300 - Environment
Terrestrial- Radioactive Materials Monitoring & Transport- (-1989)