Sweden’s programme is one of the most advanced in the world. The KBS-3 method (developed by SKB, the Swedish Nuclear Fuel and Waste Management Company) involves:
- Spent fuel placed in cast iron inserts within thick-walled copper canisters (~5m long, ~1m diameter)
- Canisters placed in individual deposition holes drilled in tunnel floors at approximately 500 metres depth in granite bedrock
- Each canister surrounded by compacted bentonite clay which swells when wet, sealing the canister from groundwater
- Tunnels backfilled with a mixture of bentonite and crusite rock
The Forsmark site in Osthammar municipality was selected following extensive geological investigations. The Swedish government approved SKB’s application in January 2022.