Onkalosyvävarastossa

Onkalosyvävarastossa refers to a deep geological repository in Finland designed for the final disposal of spent nuclear fuel. The Finnish Nuclear Waste Management Company, Posiva, is responsible for its development and operation. The repository is located in crystalline bedrock approximately 400-500 meters below the surface at the Olkiluoto nuclear power plant site. The chosen site is known for its stable geological conditions, which are considered suitable for isolating radioactive waste for hundreds of thousands of years.

The construction of Onkalosyvävarastossa involves a complex system of tunnels and deposition tunnels where the spent fuel canisters will be placed. The canisters are made of copper and will be surrounded by bentonite clay, which swells when wet, creating a tight seal that prevents water from reaching the canisters and radionuclide from migrating. The repository's design is based on the multi-barrier principle, incorporating both engineered barriers and the natural geological barrier.

The project has been in development for several decades and is one of the first deep geological repositories for spent nuclear fuel in the world to reach the construction phase. The aim is to ensure the long-term safety of the spent nuclear fuel and protect both humans and the environment from its radioactivity. The repository is expected to begin operation in the mid-2020s, marking a significant milestone in the management of nuclear waste.