MARC LET TAU In the rural municipality of Stadel, in the Zurich lowlands near the German border, everyday life has been pretty tranquil for the past few centuries. The landscape, sculpted by glaciers and bordered by wooded hills, is shaped by agriculture. Here, amidst the fields unspoiled by a single building, quarrying work has begun. Rich deposits of gravel, another legacy from previous ice ages, are being removed. After a period of relative peace and quiet, Stadel is now at the centre of a dynamic project set to last a millennium: it is to become the entrance to a massive underground disposal site for radioactive waste. The Swiss National Cooperative for the Disposal of Radioactive Waste (Nagra) spent almost 50 years looking for a site where this waste could be stored for good. In September 2022, it decided on Stadel, owing to the thick strata of stone lying deep beneath the ground there. The Opalinus clay found in Stadel offers the safest possible solution for containing radioacKeeping a lid on nuclear waste for eternity Switzerland produces nuclear energy. This process creates highly toxic, radioactive waste, which must be stored safely for thousands of years. After 50 years’ intensive searching, a decision has been taken as to where this hazardous waste should be buried. Plenty of questions nonetheless remain unanswered about this disposal site, which is scheduled to cost 20 billion Swiss francs. tive substances, Nagra experts argue. The director of Nagra, Matthias Braun, said that Stadel “offered the best safety reserves” of all the locations they had examined. He conspicuously failed to mention that alongside the site being the best for geological reasons, local political resistance to the project is also low. Thinking in unfathomable timespans Shafts up to 900 metres in depth are to be dug into the ground near Stadel. These shafts will provide access to the caverns that will be carved out of the thick Opalinus clay and used for storing radioactive waste. Nagra has to think in terms of unfathomable timespans: according to current knowledge, low- and medium-level radioactive waste needs to be stored safely for 30,000 years. As for highly radioactive waste, Nagra is working on the assumption that it will need to be stored for around 200,000 years. The safety reserves should be designed to prevent the raNagra has carried out test drilling, such as here in the vicinity of Stadel, into the deep layers of underground rock. The magic ingredient is Opalinus. It is currently believed to be suitable for storing radioactive waste. Photo: Keystone Swiss Review / December 2022 / No.6 13 Nature and the environment
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