Sweden building storage site for spent nuclear fuel

Sweden has started building a final storage facility for spent nuclear fuel, only the second such site in the world, where highly radioactive waste will be stored for 100,000 years.

How to store deadly radioactive waste until it is safe is a question that has dogged the nuclear industry since commercial reactors began operating in the 1950s.

Finland is the only country close to completing a permanent storage site.

"It is hard to exaggerate the significance for Sweden and for the climate transition of the fact that the building of the final repository is under way," Environment Minister Romina Pourmokhtari said.

"They said it wouldn't work but it does."

The World Nuclear Association reckons there are about 300,000 tonnes of spent nuclear fuel globally in need of disposal.

Most of it is stored in cooling ponds near the reactors that produced it.

In addition to the spent fuel already produced, a number of countries in Europe and around the world are planning to build new reactors to provide electricity to power the transition away from fossil fuels.

The Forsmark final repository, about 150km north of Stockholm on Sweden's east coast, will consist of 60km of tunnels buried 500 metres down in 1.9 billion year old bedrock.

It will be the final home for 12,000 tonnes of spent nuclear fuel, encased in 5-metre long, corrosion-resistant copper capsules that will be packed in clay and buried.

The facility will take its first waste in the late 2030s but will not be completed until about 2080 when the tunnels will be backfilled and closed, Sweden's Nuclear Fuel and Waste Management Company (SKB) said.

The process, however, could still be delayed.

MKG, a Swedish non-governmental organisation working on nuclear waste, has lodged an appeal with a Swedish court calling for further safety checks.

It said research from Sweden's Royal Institute of Technology showed the copper capsules could corrode and leak radioactive elements into the ground water.

"We have room to wait ten years to make a decision, given this is something that has to be safe for 100,000 years," Linda Birkedal, chair of MKG said.

The Forsmark repository will cost about 12 billion crowns ($A1.74 billion) and be paid for by the nuclear industry, SKB said.

It will have room to hold all the waste produced by Sweden's nuclear power plants.

However, it will not hold fuel from future reactors.

Sweden plans to build 10 more reactors by 2045.