Dripping Toward Disaster?
Is Germany's Asse II nuclear waste repository a catastrophe in the making?
It’s Germany’s dirty little secret. No, not that one. I mean that one of the country’s temporary storage sites for nuclear waste, Asse II, is flooding. Some 12 cubic meters of water trickles in each day. This is a fair amount of water. However, for the sake of comparison, an Olympic-sized swimming pool contains about 2,500 cubic meters of water.
By all reports, the water is pumped out not long after it seeps in. However, when nuclear waste is involved, even a little bit of water can be problematic. Lower Saxony’s state minister has stated that the situation could “open a new chapter of the nuclear disaster.”
Back in 2010, the German government decided that Asse II was no longer fit for purpose. The waste currently stored there must now be retrieved, a move that will take at least a decade just to plan out and cost billions of euros, if it even can be done. In effect, the Germans are faced with the task of mining their own nuclear waste. Decades old storage cavities will have to be made structurally sound, and barrels will be removed with heavy machinery and under radiation shielding.
Asse II is an old salt mine. Salt is considered one of the better materials to store nuclear waste drums. It’s typically impervious to water and any cracks “heal” themselves. The US’s long-term waste repository (WIPP) is sited near Carlsbad, New Mexico partly because the local geology features a 2000-foot thick salt layer.
But why Asse II hasn’t worked out like WIPP? The reason may have to do with the fact that it was a salt mine first and repository second. The earlier mining activity destabilized rock faces. As the mine’s walls deform, cracks are developing in the surrounding rock, which allows water to seep in. Fortunately, this water is already high in salt, so it doesn’t dissolve the rock salt layer, but some are worried that it will corrode the nuclear waste barrels stored in the mine’s cavities.
An old broadcast by the NDR (Norddeutscher Rundfunk) is surprisingly prescient. Water infiltration was already a known problem at Asse II in 1965, and an interviewed politician from the Social Democrat Party expressed considerable reservations about the project. But not everyone agreed. The broadcast also included an interview with an expert who contended that any water at the depths of the depository becomes a thick salty “broth” that will never make it way to the fresh water lying above.
Most reports on the leaks at Asse II mention groundwater contamination as a risk but say little about drinking water specifically. Readers of this Substack will be aware of the difference because of our work on produced waters in New Mexico. Not all water deposits in the Earth contain clean, drinkable water, nor are they all connected.
News reports insinuate a potential threat to people but (as far as I can tell) never directly demonstrate it. Given that the nuclear waste is stored 750 meters below the surface (around 2500 feet), how should we weigh the contamination risks of Asse II?
At some point, humans invariably say “Jesus, take the wheel” and trust that geological scenarios and engineering designs developed on computer screens translate to reality over the long term. Everyone else is left wondering, “What if?”
Michael Schwartz, a German geologist, has developed a computer model to explore that risk. Simulating the geology above the for several thousand years, Schwartz uncovered scenarios in which a radioactive plume reached within 1000 feet of the surface. Does that threaten local drinking water? That much is not clear from Schwartz’s paper. Nevertheless, he warns that even his pessimistic scenario “may not be pessimistic enough for a realistic worst-case scenario.”
That said, Asse II doesn’t have to actually be a clear and present danger to water supplies to become “politically unsafe.” Recall my review of The Leak, where an unambiguously harmless tritium plume almost led to the closure of Brookhaven National Labs. Regarding of the estimated danger, a flooded Asse II repository would terrorize locals with frightening uncertainties. How long will my water remain uncontaminated with invisible radionucleotides? Will my (great) grandchildren be safe here?
At the same time, the outcome would further undermine citizens’ trust in the people in charge of stewarding Germany’s nuclear waste. Should leaking storage barrels create a bubbling atomic bouillabaisse in Asse II’s mine shafts, nuclear officials and experts will look like amateurs.
Even if this nuclear concoction ends up being relatively geologically immobile, it would do little to lessen public worries. The shear fact that the waste would no longer be recoverable, or really “manageable” in any way, would undermine the portrayal of waste disposal as rational, precise, and carefully executed act of engineering.
In short, nuclear repositories have an unavoidable image problem. At some point, humans invariably say “Jesus, take the wheel” and trust that geological scenarios and engineering designs developed on computer screens translate to reality over the long term. Everyone else is left wondering, “What if?”
That hasn’t stopped repository projects from moving forward around the world. Whether or not we feel a moment of panic in an airplane taking off or landing probably has a lot to do with how recent the latest air disaster was. Similarly, people’s belief that their government can get waste storage right depends on the extent to which their countries’ nuclear engineers and regulators have proven their trustworthiness.
Yet, if there’s anything that the history of technology shows, it is that public trust can evaporate quickly after a major misstep. Even if large storage repositories are the most studied and seemingly economic option today, it would be worthwhile to dream up other options. Are there approaches that would not be so reliant on the constant maintenance of public trust? Politically safe nuclear storage options will ultimately be the most stable options.
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