Nuclear energy is capable of generating clean electricity, continuously and in large quantities. A marvel except for two small details: the risk of a possible leak and what to do with its waste. The most widespread solution is bury them in a nuclear cemetery and wait. How much? Well, it depends, but it could be hundreds of thousands of years, until they are no longer dangerous. The million dollar question is where. An international research team led by Germany has started to drill a hole in a Swiss mountain to try to answer it.
The project. Her name is DEBORAH (Deep borehole to resolve the Mont Terri Anticline Hydrogeology), stands for deep drilling to understand the hydrogeology of the Mont Terri anticline and is exactly what it does. Your goal? Document in great detail the layers that exist and their properties. There is some especially interesting material: Opalinus Clay.
This deep experiment involves the German Geosciences Research Center GFZ and the German Federal Institute for Geosciences and Natural Resources (BGR), the Nuclear Waste Service (NWS) of the United Kingdom and Swiss researchers from the University of Bern.
Why is it important. Because it can be the ideal rock to build a radioactive waste deposit. As details GFZSwitzerland has already made the decision, but Germany and the United Kingdom (the other parties to the project) have not yet. The key is what the analysis of the drilling says: details such as how much water it allows to filter, at what speed or where it will be key to making the decision. It is not trivial: a leak, no matter how slow and small, can contaminate aquifers.
What’s special about it. The Opalinus is a clay rock dating back to the Middle Jurassic, with an estimated age of approximately 175 million years. Simply put, it is clay that has been compacted into rock. And it has a property that makes it a good candidate for nuclear storage: its very low permeability.
Context. The study of Opalinus is not new by any means: GFZ’s on your radar for 30 years because, in addition to its very low permeability, it has properties such as its plasticity (under pressure, warps instead of breakingsomething convenient if it works as a radioactive deposit) or its ability to retain certain radionuclides. Switzerland has already chosen it, but it remains to be known how it behaves under the conditions that exist in much deeper areas, where, for example, temperature or pressure change noticeably.
How they do it. In the Swiss canton of Jura, near the municipality of Saint-Ursanne, there is that Mont Terri. In its bowels there is an underground laboratory that is accessed through the security gallery of a highway tunnel, about 150 – 200 meters underground. A drilling platform works continuously there, advancing meter by meter, until reaching a depth of 800 meters.
The drill uses a hollow crown that allows extracting intact rock columns, the sample that is later analyzed in the laboratory. Each advance works as a witness insofar as it reveals the age, the composition, the fractures and the differential quality: how it behaves with water. In addition, they use seismic and gravimetry techniques to obtain a complete x-ray of what is hundreds of meters deep.
In Xataka | 700 tons of nuclear waste have arrived in Germany from England. The Germans are not entirely happy
Cover | Ilja Nedilko and Evangelos Mpikakis
GIPHY App Key not set. Please check settings