100,000-year lifespan: World’s first nuclear waste repository gets operating license

Finland has issued the world’s first operating license for a final disposal facility for spent nuclear fuel, clearing Posiva Oy to encapsulate and permanently dispose of used reactor fuel deep underground until the end of 2070, the Finnish government announced.

The license covers fuel from the Olkiluoto and Loviisa nuclear power plants. It applies to a site in the Olkiluoto power plant area made up of an above-ground encapsulation plant and a repository, known as Onkalo, built more than 400 meters (about 1,300 feet) deep.

Climate and Environment Minister Sari Multala said it is “our responsibility across generations” to ensure nuclear power is used safely, from construction through to final disposal. After more than 40 years of systematic effort, she said, Finland will launch the first final disposal facility for spent nuclear fuel in the world.

The regulator’s green light

The government acted after Finland’s Radiation and Nuclear Safety Authority (STUK) issued a favorable statement on Aug. 4, 2026. STUK found that the facility meets the safety requirements of the Nuclear Energy Act and Decree, with due consideration for public and worker safety and environmental protection.

Posiva is responsible for the project’s safe implementation. Its owners, Teollisuuden Voima (TVO) and Fortum, must ensure the operations have sufficient financial resources.

How much, how fast, how long

Posiva may possess, process, store and dispose of up to 6,500 metric tons of uranium (about 7,200 U.S. tons) in spent fuel. That corresponds to about 3,300 disposal canisters. Once operations are fully established, the plan is to dispose of no more than 60 canisters a year.

Disposal is expected to continue until the 2120s, after which the repository will be backfilled and closed. After closure, responsibility for the spent fuel passes to the Finnish state under the Nuclear Energy Act. Posiva must specify and store the data essential to disposal operations so the state can use it afterward.

The facility relies on a multi-barrier containment framework designed to isolate radioactive material for thousands of years. According to Posiva, the facility is designed to safely isolate radioactive material for at least 100,000 years.

Conditions attached

The license adds conditions for a disposal facility for low- and intermediate-level waste, and it requires a periodic safety assessment and an updated long-term safety justification. Posiva may handle low- and intermediate-level waste from the plant and from its shareholders’ nuclear facilities, provided the total never exceeds 3,000 cubic meters (about 106,000 cubic feet). No more than 1,500 cubic meters (about 53,000 cubic feet) of that can be disposed of permanently. Limited amounts of other radioactive waste, including some from healthcare and research institutions, are also permitted.

Posiva must give STUK its periodic safety assessment and updated safety justification within 10 years of the license being granted, and further assessments will follow during operation.

One more step before disposal

The license does not let Posiva start immediately. STUK will supervise the completion of commissioning and the operation of the facility, and it can require remedial measures to improve safety. Before commissioning, STUK must conduct an inspection under section 20 of the Nuclear Energy Act to confirm that all conditions for safe operation are met. Until then, Posiva may not start operating the facility.

The government calls Onkalo the first final disposal facility for spent nuclear fuel in the world to receive an operating license. The release does not say when the inspection will take place or when the first canister will be disposed of.