Finland Licenses Onkalo Nuclear Waste Repository, Capped at 6,500 t Uranium

Finland's government granted Posiva an operating licence for its Onkalo nuclear waste repository, a spent nuclear fuel facility, on 22 October 2026, the first such licence in the world, according to a government statement reported by dpa.

The licence lets Posiva encapsulate and permanently store spent fuel from the Olkiluoto and Loviisa nuclear plants at Olkiluoto island in Eurajoki. The government said a maximum of 6,500 metric tons of uranium may be stored, and that the facility can be used for about a hundred years before the repository is sealed. Yle reported that the Radiation and Nuclear Safety Authority (STUK) gave a favourable assessment in August, saying the licence requirements were met.

Why Finland's Licence Matters for Nuclear Economics

Waste disposal is the part of the nuclear fuel cycle that has stalled in most countries, and Finland now has a licensed end point for it. For reactor owners and for buyers of nuclear power, that turns an open-ended liability into a defined facility with a stated capacity. Voltgrid has followed the demand side of Finnish nuclear, including Google's agreement to buy up to 50% of Loviisa output, and the Loviisa plant is one of the two sources of fuel the repository will take.

Finland's law put the cost and the duty on the owners. Fortum said in a statement dated 23 October that the principle rests on a 1994 reform of the Nuclear Energy Act, which required waste generated in Finland to be disposed of domestically and banned import and export of nuclear waste for final disposal. Posiva was set up by Fortum's predecessor Imatran Voima and Teollisuuden Voima to carry that responsibility.

How Onkalo Works and How Sweden Compares

The above-ground encapsulation plant seals fuel in canisters with a cast iron insert inside a 5-centimetre copper shell, a Posiva spokesman told dpa. The canisters are lowered into boreholes in the rock and surrounded by bentonite clay. Onkalo, Finnish for cave, lies more than 400 metres deep; Yle put the depth at 400 to 450 metres. Interesting Engineering reported a capacity of roughly 3,300 canisters and up to 60 canisters a year once operations run fully, and a licence valid through 2070. Voltgrid has not seen those two figures in the government statement, so treat them as that outlet's reporting.

Interesting Engineering noted that Sweden is building its own repository at Forsmark with the same KBS-3 method, which would make it the second country to build a permanent site. Professor Juhani Hyvarinen of LUT University told Yle that delays elsewhere came more from political obstacles than from technology, and that the technology was first licensed from Sweden and completed in Finland.

What Is Not Confirmed Yet About Disposal

The licence does not start disposal. Posiva must finish commissioning, testing and inspections, and STUK must review and approve that work before any fuel goes underground. Posiva chief executive Ilkka Poikolainen said there is no precise timetable yet and that the final steps will be taken carefully. The next dated step is therefore STUK's decision on commissioning, which has no announced date.

Climate and Environment Minister Sari Multala described the decision as the result of more than 40 years of systematic effort and called it a responsibility across generations.