Excavation of a long-planned underground spent nuclear fuel repository near the Olkiluoto power complex in Eurajoki has commenced, according to nuclear waste disposal firm Posiva.
The company said that the Radiation and Nuclear Safety Authority STUK has found that the conditions for starting excavation have been met.
Posiva, which was founded by the utilities TVO and Fortum, is the company in charge of disposing spent nuclear fuel and has been working on efforts to construct the repository for the past 15 years.
Authorities formally approved the underground construction project in late 2015.
The geological nuclear waste disposal facility will be the first of its kind in the world, according to Posiva.
First 18 months
Over the next year and a half, the company plans to dig the site's first five tunnels, which are planned to eventually grow into a network of around 100 tunnels totalling around 35km over the course of the next century.
Posiva said it estimated that the disposal site would begin operations in the mid-2020s. However, the actual encapsulation of spent fuel and their placement in the tunnels would commence once the government grants the disposal facility's operating licence.
The company said that one hundred deposition tunnels will be excavated during the 100-year operational period of the final disposal facility, totalling a length of about 35 kilometres.
Each tunnel can accommodate approximately 30 containers with a capacity of about 65 tonnes of spent nuclear fuel. The maximum length of each tunnel is 350m and roughly 4.5m tall and 3.5m wide, according to the company.
Dozens of contractors and around 300 employees currently work at Posiva's construction site, according to the company.