Safeguarding Geological Repositories Using Geophysical Monitoring and Satellite Imagery

Geophysical techniques that can sense activities or objects at a distance through the rock potentially simplify safeguarding of geological repositories during the pre-operational and operational phase by two monitoring tasks: First, the verification (and localization) of activities related to the excavation and the backfilling processes. Second, the detection of undeclared cavities ‘hidden’ behind walls of declared tunnels and shafts, either excavated before or during the operational time, including undeclared access routes. Along with geophysical techniques, remote sensing using Earth Observation (EO) satellites can play an important role in safeguarding geological repositories. Satellite imagery can assist in establishing baseline data, monitoring the geological repository for design information verification (DIV) and detection of undeclared activities. However, while satellite sensors can only monitor what is happening on the surface, they can monitor frequently and see things which may not be apparent to an inspector on the ground. After the operational phase, when all underground cavities will have been backfilled, spaceborne remote sensing and geophysical techniques are virtually the only unattended technical tools that could gain information about potential attempts at getting access to the disposed nuclear material. Here, the tasks of either technique could be to detect mining and related activities that would be needed to re-create pathways for access to the canisters. The given paper will provide the technology principle and brief description of geophysical monitoring and satellite imagery, present the potential application of either technique for safeguarding geological repositories and discuss some practical aspects in terms of technology readiness level, technology limitations, costs, sustainability, standardization, supply chain, ease of use, authentication and false alarm rates. As outlook, data acquisition from airborne platforms (including unmanned aerial vehicle (UAV)), will also be considered.