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
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.
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.
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.
Read more at Radioactive waste dogs Germany despite abandoning nuclear power