NAGRA Opalinus Clay (…002 - Version 1
FEP 12.1.9 Heterogeneity within OPA

The presence of discontinuities such as faults, deformation zones and layers with significant amount of materials with a low clay content (sand lenses, etc.) can influence the hydraulic, mechanical and radionuclide sorption properties of the host rock. In the extensive high-resolution 3D seismics campaign conducted in the potential siting region as part of the basis for this safety assessment, no previously undetected discontinuities that would have to be avoided when constructing the emplacement tunnels (layout-determining features) were observed.