Finland’s government grants operating licence for nuclear waste repository

Finland’s government granted an operating licence on October 22 for Onkalo, the world’s first permanent underground repository for spent nuclear fuel, Al Jazeera reported, citing waste-management company Posiva. The licence is a step towards permanent disposal, but does not itself allow the facility in western Finland to open.

The decision comes 22 years after construction began. Most nuclear waste remains in temporary storage, according to Al Jazeera; Onkalo is designed to provide a permanent destination for spent fuel—the fuel left after use in a nuclear reactor.

How the fuel will be stored

Onkalo has space for 6,500 tonnes of uranium and is intended to store spent fuel from Finland’s five nuclear reactors. The waste will remain highly radioactive for tens of thousands of years.

The planned containment system uses copper canisters that are highly resistant to corrosion. The canisters will hold the spent fuel and be lowered into holes drilled into bedrock. Those holes will be filled with bentonite clay and sealed with a steel-reinforced concrete plug.

According to Posiva, after about 100,000 years the waste’s radioactivity will be about the same as that of the uranium ore from which the fuel was made.

What must happen before disposal begins

Posiva said it expected operations to begin soon, but no exact start date had been decided. The company must first finish commissioning—the tests and inspections needed before operation. Finland’s Radiation and Nuclear Safety Authority, known as STUK, must verify and approve that work before final disposal begins.