LONG-TERM ISOLATION OF RADIOACTIVE WASTE IN DEEP CLAY FORMATIONS - FRACTURES AND FAULTS AS POSSIBLE PATHWAYS FOR GROUNDWATER PERCOLATION
Some radioactive wastes need to be isolated during many thousands of years. Geological formations of different types have been proposed as suitable natural barriers for radioactive waste isolation. Argillaceous formations can have very favourable characteristics, such as: + low permeability, + high plasticity, + high sorption capacity. Mathematical models of radioactive waste disposal in deep clays indicate that waste will be successfully isolated provided there is no interference by geologic processes or human activity. In some cases argillaceous materials appear to have a certain fracture permeability. In many clay quarries fissures surrounded by oxidation zones one or two cm thick have been observed, they can occur more than 100 m below the original ground surface. The oxidation zones appear to be due to oxides and hydroxides of Fe**3+. An understanding of the mechanism and rate of formation of oxidation zones in clays would allow us to decide whether the oxidation zones must be considered proof of long-term water circulation at depth or merely near surface features formed after excavation and stress relief of the clays.
Bibliographic Reference: FIRST SPANISH-ITALIAN CONGRESS ON "CLAYS AND CLAY MINERALS", SORRENTO (ITALY), SEPT. 24-29, 1984 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 31503 ORA
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Record Number: 1989123107000 / Last updated on: 1987-01-01
Available languages: en