It'll Be the First Permanent Nuclear Waste Site on Earth

After decades of construction, the world's first facility for permanently disposing spent nuclear fuel is set to begin operations in Finland, becoming a final resting place for tons of dangerous radioactive waste, reports the AP. Construction of Onkalo—which means "cave" in Finnish—began on the west coast in 2004. It sits on the secluded island of Olkiluoto, in a dense wooded area, and authorities are expected to grant the $1.2 billion project a license within months. The AP took a tour of the facilities where humans soon will not be allowed to tread.

Geologist Tuomas Pere said the site, near three of Finland's five nuclear reactors, was chosen for its migmatite-gneiss bedrock, which is known for its high stability and low risk of earthquakes. Using unmanned machinery at a nearby encapsulation plant, radioactive rods will be sealed in copper canisters and then buried deep in tunnels over 1,300 feet underground, then packed in with "buffer" layers of water-absorbing bentonite clay. The final disposal canisters are designed to remain sealed "long enough for the radioactivity of spent fuel to decrease to a level not harmful to the environment."

Posiva, the company responsible for the long-term management of Finland's spent nuclear fuels, estimates it will take hundreds of thousands of years before the radioactivity falls to normal, background levels. Posiva says Onkalo can store 6,500 tons of spent nuclear fuel. According to a 2022 report by the International Atomic Energy Agency, almost 400,000 tons of spent fuel have been produced globally since the 1950s, with two-thirds remaining in temporary storage and one-third being recycled in a complex process.

There is currently no permanent underground disposal facility for commercial nuclear waste operational anywhere in the world. Sweden began building a repository in Forsmark last year, but it's not expected to open until the late 2030s. France's Cigéo project has yet to begin construction and has seen opposition. The Onkalo facility is expected to operate until the 2120s, when it will be permanently sealed. Read the full story for more, including one warning that geologic disposal of nuclear waste is still fraught with "uncertainties."