Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 to 1000 nanometres (10−9 meter) but usually is 1 to 100 nm (the usual definition of nanoscale).
Radiation isn't the only problem of burying radioactive waste deep underground — waste also produces dangerous gases. An EU-funded project has forged a better understanding of how waste gases flow around and out of geological repositories to help national organisations ensure the process is safe.