Technical Report NTB 85-46

Knowledge of the host rock and surrounding rock strata is of fundamental importance for concepts which provide for final disposal of radioactive waste in geological formations.

Taking the studies in the Stripa Rock Laboratory into account, the objectives of the Grimsel Test Site were defined as follows:

• Checking the applicability of foreign research results to geological conditions in Switzerland
• Carrying out specific experiments which are necessary in the context of the Nagra disposal concepts
• Acquisition of know-how in planning, implementation and interpretation of underground tests in different experimental areas
• Acquisition of practical experience in development, testing and use of experimental apparatus and measurement methods.

At Grimsel, experiments are to be carried out in the following fields:

• Excavation tests
• Migration
• Rock stress measurements
• Neo-tectonics
• Geophysics
• Heat-induced processes
• Hydrogeology
• Laboratory experiments

Various tests are already under way.

The Grimsel Test Site was established between April 1983 and May 1984. It lies at a depth of 450 m under the Juchlistock and is reached by an access tunnel.

The Test Site is operated by Nagra. The experiments are carried out by Nagra and the following two German research establishments: the "Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)" and the "Gesellschaft für Strahlen- und Umweltforschung (GSF)", both under the auspices of the German "Bundesministerium für Forschung und Technologie (BMFT)".

The responsibility for the project Grimsel Test Site lies with the Engineering Division of Nagra, headed by A.L. Nold. The project leader is R.W. Lieb who also compiled the present report. The descriptions of the various investigation programs and the chapter on geology-hydrogeology in this report are based on detailed documentation provided by the principal investigators in each field.