Finland develops Onkalo, the world's first permanent nuclear waste repository

Exam-focused facts from the 26 April 2026 current affairs briefing.

Key facts

Finland is constructing the Onkalo facility, a permanent underground repository for highly radioactive waste, located on the island of Olkiluoto.
The facility is situated 400 to 450 metres below the surface in bedrock approximately 1.9 billion years old.
The repository employs a multi-layered safety system consisting of metal canisters, corrosion-resistant copper capsules, bentonite clay, and solid rock.
The Onkalo facility is designed for passive safety to remain secure for up to 100,000 years without human intervention or active monitoring once sealed.
The repository is designed to hold approximately 6,500 tonnes of Finland's spent nuclear fuel.