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Bentonite as a containment barrier for the disposal of highly radioactive wastes


The project for the storage of highly radioacitve waste in Switzerland is characterized by a system of successive safety barriers. One of these barriers is the highly compacted bentonite backfill. The functions of this bentonite backfill are described and some investigations of the important properties as swelling and water uptake are presented. In order for the radioactive material to leak out into the biosphere, water from the surrounding rock has to reach the steel canisters, and these have to be broken through by corrosion. Conservative estimates call for a time of at least 1000 years. After this period the activity of the waste comes mostly from actinides. Breakthrough time for actinides is estimated at 10'000 - 1'000'000 years. The long-term stability of montmorillonite under elevated temperature and pressure has been examined by the investigation of K-bentonites of Kinnekulle (Sweden).


Bucher, Felix and Müller-Vonmoos, Max

Index Terms:

Soil; SoilGroup; Bentonite; Waste Disposal; Swelling

Further Information:

Date published: 1989