onkalo
Onkalo is the deep geological repository for spent nuclear fuel being developed at Olkiluoto in Eurajoki, western Finland. The name Onkalo means a hollow or cavern in Finnish. The project is designed to isolate high-level radioactive waste by placing spent fuel canisters in tunnels carved into stable granite bedrock beneath the surface, roughly several hundred meters underground.
The repository uses a multi-barrier concept to prevent radionuclide release. Spent fuel is sealed in corrosion-resistant
Onkalo is operated and developed by Posiva Oy, a joint venture owned by Teollisuuden Voima (TVO) and
Construction and development have progressed through extensive engineering, safety analyses, and regulatory review. Finland’s nuclear safety