Stuk said it was beginning the review of the application for the Onkalo encapsulation and final disposal facility at Olkiluoto in the southwest of the country after concluding that Posiva had submitted sufficient material. Posiva is the company responsible for the final disposal of spent nuclear fuel in Finland.
Stuk said at this stage it was impossible to give an accurate estimate of the how long the review will take.
Posiva submitted its application for a licence to operate a spent fuel encapsulation and disposal facility to the government in December 2021. At the same time, it submitted the accompanying licence application material to Stuk for evaluation.
The application is for an operating licence for the final disposal of spent fuel generated by Finland’s commercial nuclear power plants at Olkiluoto and Loviisa, measured by Posiva as 6,500 tonnes of uranium. There are two plants in operation at each site, with one more nearing completion at Olkiluoto.
Posiva is likely to become the first operator in the world to start deep geological final disposal of spent nuclear fuel.
In November 2015 the company was granted a licence by the government for the construction of facilities at the site, in the municipality of Eurajoki. Actual construction work began in June 2019.
Posiva said final disposal at the facility is scheduled to start in the mid-2020s.
The company has estimated the total cost of final disposal at €3bn, with the long service life of the facility contributing most to that figure.
Posiva has been working for several decades at the Onkalo site to develop a concept for final disposal and demonstrate long-term safety. In May 2021, excavation began of final disposal tunnels.
In the final disposal facility, spent fuel assemblies will be encapsulated and placed in the bedrock at a depth of about 400 metres. The facility comprises two sections: the above-ground encapsulation plant for the encapsulation of the spent fuel in canisters, and the final repository deep in the bedrock, with tunnels in which the spent fuel will be placed.
About 30 spent nuclear fuel canisters will be placed in a tunnel, although the exact number depends on how many deposition holes there are – a decision determined by the volume of suitable rock. Thirty canisters can accommodate about 65 tonnes of spent nuclear fuel.
It is estimated that 100 deposition tunnels will be excavated during the 100-year operational period of the facility, totalling a length of about 35 km. The longest tunnel will be 350 metres. The tunnels are about 4.5 metres high and 3.5 metres wide.
In Finland, full lifecycle management of nuclear fuel is a precondition for the production of nuclear electricity.
Posiva is responsible for the final disposal of used nuclear fuel generated by operators Teollisuuden Voima Oyj (TVO) at Olkiluoto and Fortum at Loviisa. TVO owns 60% of Posiva and Fortum owns 40%.
