TVO also takes care of its operational waste and power plant
decommissioning waste. Their final disposal takes place in the
operational waste repository (VLJ repository) at Olkiluoto.
The decommissioning waste generated during the dismantling of the plant units will also be deposited in facilities to be built in the same underground repository. The repository also accommodates small radioactive waste generated in Finnish healthcare, industries, and research institutions.
Waste is packed into concrete containers and transported to the repository using a radiation-protected vehicle. In the VLJ repository, the concrete containers are placed into silos for low and intermediate level waste that have been excavated into the bedrock down to the level of 60–100 meters below the ground surface.
Low level waste consists of mixed waste polluted by radioactive substances.
Low level waste includes:
Plastic wrappings and protective clothing used during maintenance work
Replaced machinery parts and pipes from the nuclear power plant
The low level waste is packed into 200-liter drums and compressed to half of its volume using a hydraulic press. The radioactivity of the containers is measured before storage.
Intermediate level waste includes:
Ion-exchange resin from the circulating water cleaning system
Liquids from various washing processes
Sludge that forms when solid matter collects as sediment at the bottom of pumps and tanks
The ion-exchange resin is dried, mixed with bitumen, and cast into 200-liter drums.