Batches of deadly radioactive uranium will begin arriving within two years to be buried in the tunnels carved into the rock. Other countries, including the UK, are considering plans to build their own geological disposal facilities, which should safely isolate the 260,000 tonnes of highly radioactive waste that has accumulated worldwide since the dawn of nuclear power in the 1950s. Sky News had rare access to the site, called Onkalo, which means “hollow” in Finnish. It is built next to three nuclear reactors on the southwest coast of the country. Security was so tight in the wake of the Nord Stream gas pipeline sabotage that there was a strict no-filming rule above ground. But they took us down the 5km access road that cuts through the rock, so deep that our ears popped. At the bottom, other tunnels were opened. Five have been completed so far, but as many as 100 could be built in the coming decades, spanning a total of more than 40 miles. Our guide was Sanna Mustonen, a geologist and senior project manager for Posiva, the company that manages the facilities. He said the bedrock was formed nearly two billion years ago and has remained intact ever since. “The rock itself, as in the whole area of Finland, is very stable,” he said. “We have old rocks. We don’t have continental plates nearby, so we don’t have earthquakes, seismicity or things like that.” Image: Waste will be sealed in double layer metal boxes “There must be security” Like other countries, Finland stores spent nuclear fuel above ground in shielded storage facilities while it looks for a long-term solution. However, Mika Pohjonen, managing director of Posiva, said it would be irresponsible to leave such hazardous waste where it could fall into the wrong hands. He told Sky News: “If you look at history, 300 years back, how many wars have there been in Europe, for example? “On the surface interim storage needs active human measures, the building needs to be heated, the spent fuel needs to be cooled, there is security around it. “If you look a generation ahead, you can’t really see that this kind of arrangement would be safe enough.” Various solutions to the problem of nuclear waste have been proposed, including: launching it into deep space, burying it in an ocean trench, and dumping it in a fissure in the Earth’s crust. They have been dismissed as impractical, expensive or environmentally hazardous. Image: The facility is being built on the foundation of Finland “Safe for a million years” Instead, Posiva will encase the spent nuclear fuel in double-layer metal canisters that will be drilled into holes in the floor of the tunnels. To keep them dry, they will be wrapped in bentonite, an absorbent material used in cat litter. More bentonite will be used to backfill the tunnels, which will be plugged with concrete. When the complex is full in about a century, with perhaps as many as 3,250 canisters, it will be sealed and all traces removed above ground. “It will be safe for a million years,” Mr Pohjonen said. “There may be no more people here because then there will be ice ages or [this area will be] underwater, but this is designed to keep it out of the biosphere.” The virtual boxes are already buried in bentonite and surrounded by sensors. Some scientists have warned that the water could corrode the metal, become radioactive and then rise to the surface over millennia. But Posiva says the multiple barriers keep waste in and water out. And if there was a leak in an extremely unlikely worst-case scenario, modeling shows that by the time any water reaches the surface in 10,000 years, the radioactivity would have decayed so much that it would not be a threat to life. Finland’s progress has been closely watched by other countries. Sweden has begun construction of its own deep geological disposal site. France, Switzerland and the United Kingdom are further behind. A shortlist of four potential sites in Cumbria and Lincolnshire has been drawn up. Image: The metal boxes will be buried underground Read more: New nuclear power plant given government go-ahead Inside the most dangerous building in western Europe as work begins to remove radioactive sludge Bruce Cairns, chief policy adviser at the UK Nuclear Waste Agency, also took a look at Onkalo while we were there. He said responsible permanent disposal of the waste is essential as the country commissions a new generation of reactors. “We have 70 years of waste in the UK already accumulated from power generation, defense and industrial processes. “It’s not going anywhere unless we do something about it. We need to take steps to make sure it’s managed responsibly, not just for now but for the long term.” Key to Finland’s progress has been engagement with the local community. Image: Olkiluoto nuclear power plant Locals in favor The nearest settlement is Eurajoki, about 10 miles away. Existing nuclear reactors were already major local employers and when the site was selected from a shortlist of disposal sites, the local authority voted overwhelmingly in favour. Vesa Lakaniemi, the city’s mayor, said: “We’ve had nuclear power here for 40 years. “The world knows about nuclear and final [waste] disposal much more than in the regions without a nuclear power plant. “Trust has grown over four decades.”
