A Study on Previous Cases of Seismic Reflection Surveys for Deep Geological Disposal Site Investigations in Crystalline and Sedimentary Host Rocks

Crystalline and sedimentary rocks are the preferred host rocks in deep repositories for spent nuclear fuels. This study examined the Swiss case of sedimentary rocks and Swedish and Canadian cases of crystalline rocks. In Switzerland, a reflection survey was used to identify the candidate host rock for the disposal site as the Opalinus clay formation and to create images of the boundaries of the Mesozoic sedimentary layers, including the Opalinus clay formation. A 3D reflection survey was conducted to determine the distribution and small-scale faulting of the Opalinus clay formation. Sweden conducted reflection surveys at the Forsmark site to obtain geological information on the deformation lenses within the site and to characterize the geology of the three deformation zones near the site. Canada conducted a reflection survey at the Ignace site to obtain information on its geological structure, including the location and dipping angles of the reflectors distributed in the vicinity of the site.