Nuclear mattersAlps laboratory tests methods of storing nuclear waste

Published 30 December 2008

Two test tunnels in Switzerland are used to study methods of storing nuclear waste; many scientists from around the world take part in the research

To get to the control center of the hydroelectric plant at Räterichsbodensee lake, at Grimsel Pass in Switzerland, you have to ride a cable car to reach a cable station located at a height of 5,675 feet up the mountain. Next to the station you notice a red metal door, which is the entrance to a road that leads into the mountain. Behind the door, a VW bus is waiting. The vehicle drives down a passageway that takes it deep below the surface. The tunnel leads to the control center, which is surrounded by rock.

The Swiss government is researching ways to dispose radioactive waste safely. Switzerland is home to five nuclear power plants that together provide about 40 percent of the country’s electricity, according to the International Atomic Energy Agency (IAEA). Depositing the nuclear waste in rock tunnels deep inside mountains is an option.

Mathias Rittgerott writes in Spiegel that the rock laboratory in the Aar Massif belongs to the Swiss National Cooperative for the Disposal of Radioactive Waste (NAGRA). “Here we can conduct pure research, especially because nuclear waste can never be stored here,” says the Ingo Blechschmidt, a Swiss geologist. “The Alps have been forced upward for millions of years. Every year they grow another millimeter.” It is only a matter of time before the deposited waste will reach the earth’s surface.

Switzerland maintains two rock laboratories a good distance away from potential final storage sites. The facility in Grimsel is intended to study the characteristics of granite. The second research center, far away in the canton of Jura, focuses on the nature of claystone. Scientists from around the world flock to these caverns. In addition to Blechschmidt, right now a dozen Japanese are conducting research, and an Argentinean is working on an experiment with two Swiss. Researchers from ten countries are transmitting data back to their home countries.

Water seeps through invisible cracks and fissures in the rock and forms tiny rivulets and puddles on the floor, but Blechschmidt says this is not a problem: “A dry tunnel would actually be unsuitable.” In contrast to salt, where water can cause cavities to collapse, he says that the researchers actually require a moist environment. “Granite doesn’t dissolve,” explains the geologist, “but the water causes the bentonite to swell — and this is used to encapsulate the radioactive waste containers.” When sometime during the next 200,000 years the containers that surround the radioactive waste have rusted through, a second barrier is