Safety · Eurajoki
Finland approves world's first permanent repository for spent nuclear fuel
Posiva said the Onkalo site in Eurajoki can begin operating soon, though no start date has been set. The underground facility, dug into bedrock over 22 years, will hold spent fuel from Finland's five nuclear reactors.
AI text based on reports by Mediafax.ro, Spiegel Online, RP Online and other publishers. Published . How it is made
In brief
The Finnish government approved operation of the Onkalo repository in Eurajoki, announced by Posiva on Thursday, 22 October 2026. No exact start date has been set.
The repository, bored into bedrock about 1.9 billion years old, will hold spent fuel from Finland's five nuclear reactors and has a capacity of 6,500 tonnes of uranium.
Construction began 22 years before the approval, while nuclear power plants are usually built in 7 to 15 years depending on country and reactor type.
Posiva must complete commissioning tests and inspections, which STUK must review and approve, before final disposal begins.
- Construction startConstruction of Onkalo began 22 years before the approval
- 22 OctPosiva announces that the Finnish government has approved operation of the Onkalo repository
- Before disposalCommissioning tests and inspections, reviewed and approved by STUK, must be completed before disposal begins
Government approval
The Finnish government has granted an operating licence for Onkalo, an underground repository for spent nuclear fuel in Eurajoki, south-western Finland. The waste management company Posiva announced the approval on Thursday, 22 October 2026. Posiva expects the facility to begin operating soon, but it has not fixed an exact date. The company said further commissioning work must be completed before any waste is placed underground. Chief executive Ilkka Poikolainen praised the day as a great one for both Posiva and Finland.
Construction and design
Work on the site began 22 years ago, a far longer period than the 7 to 15 years that nuclear power plants usually need to be built, depending on the country and reactor type. The repository was bored into solid bedrock that is about 1.9 billion years old. It has a capacity of 6,500 tonnes of uranium and is meant to store spent fuel from Finland's five nuclear reactors. The name Onkalo means cave in Finnish. The facility was designed to keep the waste isolated from people and the environment for far longer than any human structure has existed.
How the waste will be stored
The spent fuel will be sealed in copper canisters that resist corrosion. The canisters will then be lowered into boreholes in the tunnels cut into the rock. Posiva plans to fill the spaces around the canisters with bentonite clay, which acts as an additional protective barrier. The boreholes will then be closed with a plug of steel-reinforced concrete. The fuel will stay highly radioactive for tens of thousands of years. Posiva says its radioactivity will fall to a level comparable to that of the uranium ore it came from after about 100,000 years.
What remains before disposal
Before final disposal can start, Posiva must carry out commissioning tests and inspections. The Finnish Radiation and Nuclear Safety Authority, known as STUK, must also review and approve those tests. Posiva has not yet given a detailed timetable for commissioning, and no sources give a date for when the first waste will go underground. The company has stated that the process is still in progress.
Wider context
Countries have struggled with how to handle nuclear waste since the first power plants were built in the 1950s, and most of it is still held in temporary storage. Sweden and France are also building final repositories. Finland is expected to be the first country to open an underground one. The sources put the cost of the Onkalo site at 1.16 billion dollars.
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Sources and context
- Mediafax.roWorld's first nuclear waste repository receives operating permitPrimul depozit de deșeuri nucleare din lume primește autorizație de funcționare · original in Romanian
- Spiegel OnlineWorld's first nuclear waste repository receives operating permitErstes Atommüllendlager weltweit erhält Betriebsgenehmigung · original in German
- RP OnlineRadioactive waste from nuclear power plants: Finland approves underground repository for nuclear wasteRadioaktives aus AKW: Finnland gibt unterirdisches Endlager für Atommüll frei · original in German
- Η ΝαυτεμπορικήFinland: Nuclear waste in the depths of the Earth for 100,000 years - The first facility in the worldΦινλανδία: Στα έγκατα της Γης για 100.000 χρόνια τα πυρηνικά απόβλητα - Η πρώτη εγκατάσταση στον κόσμο · original in Greek
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