Permanent Nuclear Waste Disposal: Long-Term Storage and Safety

Context: Finland is set to become the first country in the world to operationalise a Deep Geological Repository (DGR) for the permanent disposal of high-level spent nuclear fuel.

About Onkalo

Named Onkalo (Finnish for “cave”), the facility is located 430 meters underground on the island of Olkiluoto
The site was chosen for its migmatite-gneiss bedrock, which is approximately 1.9 billion years old.
This rock is characterised by high seismic stability and extremely low permeability.

Current Global Landscape for Nuclear Waste Disposal

The International Atomic Energy Agency sets global safety standards for the management and disposal of radioactive waste.
Most countries currently use temporary storage:
- Wet Storage: Spent fuel pools at individual reactor sites.
- Dry Cask Storage: Concrete and steel containers stored above ground.
Sweden: Construction has begun on a repository in Forsmark, expected to open in the late 2030s.
France: The Cigéo project is planned for deep geological disposal but faces ongoing public and political opposition.
Recycling: About one-third of global spent fuel is recycled to extract plutonium and uranium, though this process is complex and still leaves behind high-level waste.

Important Notes

Spent Nuclear Fuel: Fuel that has been irradiated in a nuclear reactor and is no longer efficient for power generation but remains highly radioactive.

High Level Waste (HLW): Highly radioactive materials produced as a byproduct of the reactions that occur inside nuclear reactors.