The world’s first geological grave for nuclear waste is rapidly taking shape more than 400 meters below the forests of Finland.
Batches of lethally radioactive uranium will begin arriving within two years to be buried in the maze of tunnels carved into the bedrock.
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 around the world since the dawn of nuclear power in the 1950s.
Sky News received rare access to the site, called Onkalo, which means “cavity” in Finnish. It is built together with three nuclear reactors on the southwestern coast of the country.
Security was so tight after the sabotage of the Nord Stream gas pipeline that there was a strict rule of not filming on the surface.
But they took us up the 5km access road that winds through bedrock so deep our ears were covered.
In the background, more tunnels fanned out. Five have been completed so far, but as many as 100 could be built in the coming decades, stretching more than 40 miles in total.
Our guide was Sanna Mustonen, a geologist and senior project manager at Posiva, the company that manages the facility.
She said the bedrock formed nearly two billion years ago and has remained intact ever since.
“The rock itself, as in the whole area of FinlandIt’s very stable,” he said.
“We have old rock. We don’t have continental plates close by, so we don’t have earthquakes, seismicity or things like that.”
‘There must be security’
Like other countries, Finland is storing spent nuclear fuel on the surface in shielded bunkers while it looks for a long-term solution.
But Mika Pohjonen, Posiva’s managing director, 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 ago, how many wars have there been in Europe, for example?
“On the surface, interim storage needs active measures on the part of humans, the building needs to be heated, the spent fuel needs to cool down, there needs to be security around it.
“If you look a generation ahead, you really can’t see that that kind of arrangement would be risk-free enough.”
Several solutions to the nuclear industry waste problem have been suggested, including: launching it into deep space, burying it in an ocean trench, and dropping it into a fissure in the Earth’s crust.
They have been dismissed as unfeasible, expensive or risky for the environment.
‘Safe for a million years’
Instead, Posiva will encase spent nuclear fuel in double-layer metal canisters that will be placed in holes drilled 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 fill the tunnels, which will be covered with concrete.
When the complex is full a century from now, with perhaps as many as 3,250 boats, it will be sealed and all traces of the surface will be removed.
“It will be safe for a million years,” Pohjonen said.
“There may no longer be humans here because at that time there will be ice ages or [this area will be] underwater, but this is designed to keep it out of the biosphere.”
The fictional boats are already buried in bentonite and surrounded by sensors.
Some scientists have warned that the water could corrode metal, become radioactive and then rise to the surface for millennia.
But Posiva says the multiple barriers keep debris in and water out. And if there were a highly unlikely worst-case leak, the model shows that by the time the water reached the surface in 10,000 years, the radioactivity would have decayed so much that it would not be life-threatening.
Finland’s progress has been closely watched by other countries. Sweden has started construction of its own deep geological dump. France, Switzerland and the UK lag further behind.
A list of four possible sites in Cumbria and Lincolnshire has been drawn up.
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Bruce Cairns, Senior Policy Adviser at the UK Nuclear Waste Services, was also taking a look at Onkalo while we were there.
He said permanent responsible disposal of the waste is essential as the country commissions a new generation of reactors.
“We have 70 years of waste in the UK that has already accumulated from energy production, defense and industrial processes.
“It’s not going anywhere unless we do something with it. We have to take steps to make sure this is managed responsibly, not just for now but for the long term.”
The key to Finland’s progress has been commitment to the local community.
Locals in favor
The closest settlement is Eurajoki, about 10 miles away.
Existing nuclear reactors were already large local employers and when the area was selected from a list of disposal sites, the local authority voted overwhelmingly in favour.
Vesa Lakaniemi, the city’s mayor, said: “We have had nuclear power here for 40 years.
“People know about nuclear power and end [waste] disposal much more than in areas that do not have a nuclear power plant.
“Trust has been built up over four decades.”