Major problems at a salt mine where 126,000 drums of radioactive debris are stored are fuelling public distrust of long-term waste disposal plans, reports Fred Pearce from Asse, Germany
Ronald Frommann/Clean Energy Wire
Half a kilometre beneath the forests of northern Germany, in an old salt mine, a nightmare is playing out.
A scheme to dig up previously buried nuclear waste is threatening to wreck public support for Germany’s efforts to make a safe transition to a non-nuclear future.
Enough plutonium-bearing radioactive waste is stored here to fill 20 Olympic swimming pools. When engineers backfilled the chambers containing 126,000 drums in the 1970s, they thought they had put it out of harm’s way forever.
But now, the walls of the Asse mine are collapsing and cracks forming, thanks to pressure from surrounding rocks. So the race is on to dig it all up before radioactive residues are flushed to the surface.
It could take decades to resolve. In the meantime, excavations needed to extract the drums could cause new collapses and make the problem worse.
“There were people who said it wasn’t a good idea to put radioactive waste down here, but nobody listened to them,” says Annette Parlitz, spokeswoman for the Federal Office for Radiation Protection (BfS), as we tour the mine.
This is just one part of Germany’s nuclear nightmare. The country is also wrestling a growing backlog of spent fuel.
And it has to worry about vast volumes of radioactive rubble that will be created as all the country’s 17 nuclear plants are decommissioned by 2022 – a decision taken five years ago, in the aftermath of Japan’s Fukushima disaster. The final bill for decommissioning power plants and getting rid of the waste is estimated to be at least €36 billion.
Ronald Frommann/Clean Energy Wire
Some 300,000 cubic metres of low and intermediate-level waste requiring long-term shielding, including what is dug from the Asse mine, is earmarked for final burial at the Konrad iron mine in Lower Saxony.
What will happen to the high-level waste, the spent fuel and other highly radioactive waste that must be kept safe for up to a million years is still debated.
Later this year, a Final Storage Commission of politicians and scientists will advise on criteria for choosing a site where deep burial or long-term storage should be under way by 2050.
But its own chairman, veteran parliamentarian Michael Muller, says that timetable is unlikely to be met. “We all believe deep geology is the best option, but I’m not sure if there is enough [public] trust to get the job done,” he says.
Lack of trust
Many anti-nuclear groups are boycotting the commission.
Although they agree Germany must deal with its own waste, they don’t trust the process of choosing a site. They fear that the authorities are secretly fixed on reviving plans for burial at Gorleben, another Lower Saxony salt dome.
Currently, 113 flasks containing high-level waste are housed in a temporary store there.
“One flask of high-level waste contains as much radioactivity as 30 Hiroshima bombs,” says Wolfgang Ehmke, who has been a campaigner for 40 years. “We cannot bury this waste here in northern Germany [because] there could be 10 ice ages, with glaciers scraping away the rocks, before the waste is safe.”
The protesters have wide popular support. And the problems at the Asse salt mine have led to further distrust of engineers and their solutions.
The abandoned mine was bought by the German government in 1965, ostensibly to research the suitability of salt domes for disposing of radioactive waste. Yet after two years, without waiting for scientific reports, the authorities secretly turned it into a cheap and supposedly permanent nuclear dump.
By then, 90 per cent of the mine’s 5 million cubic metres of salt had been excavated, and the mine was already buckling under the weight of the rocks above, says Ingo Bautz of the BfS, who oversees activities at the site.
As the walls bent, cracks formed. And because the miners had dug to within 10 metres of the impervious rock, in 1988, underground water started to trickle in.
The true state of affairs only became public knowledge in 2008. Despite hurried backfilling of much of the mine, the degradation continues. Brine seeps in at a rate of around 12,000 litres a day, threatening to flush radioactive material to the surface. “It is a disastrous situation,” says Jochen Flasbarth, state secretary at the Federal Ministry of the Environment.
In 2011, the BfS ruled that the waste had to be removed. But the task is hard and likely to take decades. Just checking the state of the 13 chambers holding the waste drums is painfully slow. Engineers drilling to reach them through 20 metres of rock don’t know whether the drums have leaked, and of course they cannot risk a release of radioactivity.
Since work started in 2012, just one borehole has been completed into one of the chambers. Engineers say they will need to sink a second shaft and open up big new galleries where the drums can be made safe before they are retrieved.
But exploratory drilling has revealed that the salt dome is not as big as thought, says Bautz.
And unless care is taken to keep clear of the geological barrier, the excavations risk allowing more water in. “We can’t rule out that the mine could flood,” he says. “If that happened, retrieval would be impossible. We would backfill it all.”
Nothing will be moved until at least 2033, says Bautz. Meanwhile the bills keep rising. It costs €140 million a year just to keep the mine safe for work to continue. The final bill will run into many billions.
Is it worth it? Many experts fear that digging up the drums, with consequent risks of radioactive leaks, could create a much greater hazard than leaving them where they are.
A former top official on the project, geochemist Michael Siemann, told the media in 2012 that safe retrieval was unrealistic. “Many people know this, but no one wants to say it.”
“There could be a conflict between protecting future generations and creating risks for today,” Bautz concedes.
Germany may ultimately perform a service to the world if it can pioneer solutions that other nuclear countries may look to in the future, including the UK, which is struggling with its own waste legacy.
But if Germans ever thought that abandoning nuclear power would end their nuclear problems, they couldn’t have been more wrong.
Fred Pearce’s costs during the field trip to the mine were paid for by Clean Energy Wire, an independent non-profit media service.