The existing facility most similar to the proposed DGR is the nuclear waste storage facility in Asse, Germany. They are currently having problems with leakage that has contaminated local drinking water and made the facility itself dangerous for humans to retrieve the waste safely. In fact, the rock housing the facility has shifted so much that the agency responsible for the facility is having trouble even finding the waste:
The team has driven the drill pipe 35 meters into the salt, yet after a good seven months of work, they still haven’t found the chamber with the stored radioactive waste. Geologists now believe that it has been missed by roughly 2.5 meters because the mountain has a life of its own and changes shape as the salt shifts from south to north.
Facing unknown engineering challenges weighs heavily on the Asse project:
In early 2010, the federal government ordered the BfS [Germany’s Federal Office for Radiation Protection] to assess whether the radioactive waste in the Asse mine can be retrieved. The agency estimated that it would take three years to prepare the project. Most recently, the BfS said it would need 10 years for the fact-finding phase alone.
The BfS still has no detailed concept for the retrieval, no timetable, no script that maps out the technical procedures. It’s essentially a flight by the seat of the pants, and problems are encountered for which no solutions have been found anywhere in the world.
This is reminiscent of other large German infrastructure projects, in which everything during the construction phase turns out to be more difficult, time-consuming and expensive than anticipated. But the difference is that there are already plenty of underground railway stations, major international airports and concert halls around the globe. Removing nuclear waste from a flooding, collapsing salt mine, though, represents a unique challenge. “What we intend to do here has never been done before,” says Jens Kohler, the technical director at Asse.
Relevance to the Bruce DGR project: although the Ordovician limestone formation underlying the Bruce Nuclear Generating Station is more stable than the former salt mine, no other place in the world successfully uses such fragile material as limestone to store nuclear wastes — the two working DGRs (in Scandinavia) use granite. Some jurisdictions are considering using limestone, but they separate wastes on the basis of their radioactivity and keep them removed from bodies of fresh water. Note also that because the proposed Bruce DGR is so deep, and has planned for the isolation of the wastes to be achieved by the surrounding rock rather than the integrity of the canisters, retrieval of the waste could well be more dangerous and difficult than at Asse.