Evaluation of factors affecting diffusion in compacted bentonite

Book · Thu Aug 01 04:00:00 EDT 1996

OSTI ID:264472

Lehikoinen, J; Carlsson, T; Muurinen, A; Olin, M; Salonen, P

The information available from the open literature and studies on exclusion, sorption and diffusion mechanisms of ionic and neutral species in bentonite has been compiled and re-examined in relation to the microstructure of bentonite. The emphasis is placed on a more thorough understanding of the diffusion processes taking place in compacted bentonite. Despite the scarcity of experiments performed with neutral diffusants, these imply that virtually all the pores in compacted bentonite are accessible to neutral species. Anion exclusion, induced by the overlap of electrical double layers, may render the accessible porosity for anions considerably less than the porosity obtained from the water content of the clay. On the basis of the compiled data, it is highly probable that surface diffusion plays a significant role in the transport of cations in bentonite clays. Moreover, easily soluble compounds in bentonite can affect the ionic strength of porewater and, consequently, exclusion, equilibrium between cations, and surface diffusion.

• OSTI ID: 264472
• Report Number(s): CONF-951155--; ISBN 1-55899-315-0
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
BACKFILLING
BENTONITE
CALCIUM
CESIUM
CHLORIDES
EXPERIMENTAL DATA
GROUND WATER
IODIDES
MICROSTRUCTURE
PERMEABILITY
POTASSIUM
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE FACILITIES
RADIONUCLIDE MIGRATION
ROCK-FLUID INTERACTIONS
SITE CHARACTERIZATION
SODIUM
SPENT FUELS
STRONTIUM
UNDERGROUND DISPOSAL