Posiva Oy is an expert organisation responsible for the final disposal of spent nuclear fuel of the owners. Posiva has been established in 1995.
The disposal of spent nuclear fuel must be organised in a way that is not harmful to organic nature. Spent nuclear fuel from the nuclear power plants of Teollisuuden Voima and Fortum will be packed in copper canisters and embedded in Olkiluoto bedrock at a depth of 400-450 metres.
The final disposal of spent nuclear fuel is based on the use of multiple release barriers, which ensure that the nuclear waste cannot be released into organic nature or become accessible to humans. A deficiency of a single barrier or a predictable geological or other change will not endanger the performance of the insulation. The release barriers include the physical state of the fuel, the disposal canister, the bentonite buffer, the backfilling of the tunnels and the surrounding rock.
The spent nuclear fuel is packed into the disposal canisters at the encapsulation plant. The canisters are then transported by a lift to the underground repository.
The spent nuclear fuel is stored in the interim stores at Fortum's power plant in Hästholmen in Loviisa and at TVO's power plant in Olkiluoto in Eurajoki. The fuel is transported from the power plants to the encapsulation plant in special casks as special transports.
Plenty of time has been reserved for the preparatory stage and the implementation stage of final disposal. Thorough preparations and implementation will ensure the safety of final disposal. The final disposal of spent nuclear fuel is planned to start in 2020's and will continue for almost a hundred years.
photos from - http://www.posiva.fi/en/media/image_gallery?gfid_2061=94#gallery_2061
more information - http://www.posiva.fi/en