Opalinus clay

The proposed Swiss repository for SF, HLW, and ILW is situated in the Opalinus Clay of the Zurcher Weinland in northern Switzerland, where an exploratory borehole was drilled near the village of Benken (Nagra 2002a). The Opalinus Clay formation consists of a well-consolidated clay shale, which is suitable for the construction of small, unlined tunnels and larger, lined tunnels at depths of several hundred metres. The engineered barrier system includes the waste containers and the backfill of construction, operation, and emplacement... 

Bradbury Baeyens (2002a, b) provided sorption data bases for Opalinus Clay and MX-80 bentonite, respectively, based on numerous experiments with varying aqueous solution compositions. Since sorption can be influenced by the complexa-tion of radionuclides with various ligands, corrections had to be made to account for the differences in speciation between the experimental solutions and the Opalinus Clay and bentonite porewaters. For this purpose, the Nagra/PSI TDB 01 /01 was used to model the speciation of all safety-relevant radionuclides in the experimental solutions and in the Opalinus Clay and bentonite porewaters. 

Berner, U. 2002a. Project Opalinus Clay Radionuclide Concentration Limits in the Near-Field of a Repository for Spent Fuel and Vitrified High-Level Waste. Nagra Technical Report NTB 02-10, Nagra, Wettingen, Switzerland. Also issued as PSI Bericht Nr. 02-22, Paul Scherrer Institut, Villi-gen, Switzerland. 

Bradbury, M. H. Baeyens, B. 20026. Far-Field Sorption Data Bases for Performance Assessment of a HLW Repository in an Undisturbed Opalinus Clay Host Rock. Nagra Technical Report NTB 02-19, Nagra, Wettingen, Switzerland. Also issued... 

AfTEMIN (2001). Engineered Barrier Emplacement. Experiment in Opalinus Clay EB" Experiment. Internal Report. AfTEMIN, Madrid... 

Table 1. Hydro-Mechanical Properties of Boom Clay (Horseman et al. (1987) Bernier and Van Cauteren (1998)) and Opalinus Clay (Thury et al. (2000) Harrington et al. (2001)).

Terri gallery in Switzerland. It is located in the Opalinus clay made of argilites at a depth of 250 meters. A horseshoe shape is assumed in this case. The initial state of the stress and pressure is given by ... 

Appelo C. A., Wersin P. (2007) Multicomponent Diffusion Modeling in Clay Systems with Application to the Diffusion of Tritium, Iodide, and Sodium in Opalinus Clay. Environ. Sci. Technol. Vol. 41, p. 5002-5007. 

An experimental set up (high pressure triaxial cell and local strain measurement system) and an experimental procedure have been developed in order to quantify the permeability evolution with deviatoric stress on clays of very low permeability. Developed techniques have been improved on concrete and sandstone. We are able to detect with precision strain localization and we are able to measure with the pulse method, permeability, at different stages of loading. A testing program on both Boom Clay and Opalinus is in progress. 

Chermak, j. a. 1992. Low-temperature experimental investigations of the effect of high pH NaOH solutions on the Opalinus shale, Switzerland. Clays and Clay Minerals, 40(6), 650-658. 

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