f A High-Resolution 3D Vibroseis Trial Survey of a Potential Nuclear Waste Repository

United Kingdom Nirex Ltd is responsible for providing and operating a repository for the disposal deep underground of intermediate-level radioactive wastes and certain low-level wastes (UK Nirex Ltd 1993). It is focussing its investigations at a Potential Repository Zone (PRZ) near Sellafield, West Cumbria, where the Ordovician Borrowdale Volcanic Group (BVG) at 400- 600 m depth below the surface holds good promise as an eventaal repository host rock. The voicanics are overlain by Permian breccias and Triassic sandstones dipping gently SW, and are cut by normal faults mainly trending along strike. Within the PRZ, Nirex is planning to construct an underground Rock Characterisation Facility (RCF) to study the safety and engineering properties of the BVG.