Overview of the programme forseen for the potential site Oberbauenstock (Community Bauen UR)

On 30th September 1985, the Federal Government licensed site suitability investigations in three areas with a view to disposal of low-and intermediate-level radioactive waste. This report gives a summary overview of the corresponding research programme at the potential site Oberbauenstock. The first part of the report begins with some comments on the concept of radioactive waste disposal and on some basic aspects of site-specific exploration and investigation. The governmental decision of 30th September and Nagra's two-phase investigation concept are then briefly considered. To close, the objectives of investigation phase I are outlined and possible results are briefly discussed. The research programme developed for investigation of the potential site at Oberbauenstock is presented in the second part of the report. Besides geological and hydrogeological investigations at the surface, the programme mainly comprises investigations and measurements in the underground structures of the Seelisberg Tunnel. These include an exploratory borehole and a reflection seismic line for improved recording of the host rock geometry, as well as geophysical measurements and four short boreholes for petrophysical and hydrogeological characterisation of the host rock. Further sections are devoted to possible additional work and the time-planning of investigation phase I. The third part of the report gives a brief overview of the most important investigations in the research programmes for the other two potential sites, Bois de la Glaive and Piz Pian Grand. (author)