Finland nearing opening of world’s first permanent nuclear waste repository

Finland has granted an operating licence for the world's first permanent underground repository for spent nuclear fuel, a milestone in the nuclear industry's decades-long search for a final resting place for its most dangerous waste.

The government handed the Onkalo facility, in western Finland, the licence on Thursday, waste management company Posiva said. Onkalo — Finnish for "cave" — has room for 6,500 tonnes of uranium and will permanently store spent fuel from Finland's five nuclear reactors.

The licence does not yet allow the facility to open, but operations are expected to begin soon, 22 years after construction began. No exact date has been decided.

"This is a great and historic day for both Posiva and Finland," the company's Chief Executive Officer Ilkka Poikolainen said in a statement. Before final disposal begins, Posiva will complete the commissioning stage — the tests and inspections that Finland's Radiation and Nuclear Safety Authority (STUK) must verify and approve.

The spent fuel will be sealed in copper canisters designed to resist corrosion. The canisters will be lowered into holes drilled into the bedrock, packed with bentonite clay and sealed with a steel-reinforced concrete plug.

The waste will remain highly radioactive for tens of thousands of years. After about 100,000 years, its radioactivity will have fallen to roughly the level of the natural uranium ore the fuel was made from, according to Posiva.

Countries have wrestled with what to do with nuclear by-products since the first plants were built in the 1950s, and most spent fuel today sits in temporary storage. Similar permanent repositories are being built in Sweden and France, but Finland is expected to be the first to open its underground storage facility. The Onkalo project is estimated to have cost $1.16bn.