What to do with nuclear waste? How do we store it safely in the long term? The answer to that question has eluded the nuclear industry for sixty years. Some isotopes in the waste produced by nuclear reactors are dangerous for hundreds of thousands of years. But we have yet to come up with a way of storing them safely to protect ourselves and future generations.

Many are looking to Sweden and the storage method its scientists are currently working on. The project hopes to store high-level nuclear waste 500 metres underground for 100,000 years (plutonium, unfortunately, is still dangerous after 250,000 years). The waste will be sealed in copper-coated containers and then buried in bentonite clay. And there is will sit, it is hoped, for a hundred millennia.

But there’s a problem. The thickness of the copper surrounding the waste is planned to be five centimetres thick. There have been many doubts about this solution and now scientists at the Swedish Royal Institute of Technology have just released a paper saying that this protection isn’t enough to stop the copper from corroding, the containers rupturing and them leaking their contents.

One of the scientists says that in the worst case, the containers may only last 1,000 years. According to the paper, the copper would need to be one metre thick to stay safe for 100,000 years. That’s a lot of copper – the storage containers each weigh 25 tonnes.

This research needs to be evaluated and followed up. We’ll be watching closely. But if these findings are corroborated, the current best hope for long term nuclear storage – as it currently stands – will have been found to be a failure. Nuclear waste remains a puzzle without a solution.