Nagra planning two more deep boreholes
The National Cooperative for the Disposal of Radioactive Waste (Nagra) will conduct a deep borehole in the community of Rheinau, which is located in the Zürich Nordost siting region. “In Rheinau, the focus is no longer on completing the picture of the underground for Zürich Nordost. The previous boreholes in Trüllikon, Marthalen and Benken have already provided us with a very clear understanding. We are primarily interested in the behaviour of the Opalinus Clay in the vicinity of fault zones”, explains Tim Vietor, Nagra Division Head Safety and Geology. The tight Opalinus Clay rock will eventually host the deep geological repository.
Important insights for all three regions
In earlier investigations, Nagra identified deep underground faults with a vertical trend in the eastern part of the Rheinau community. The aim now is to clarify how these faults develop in the Opalinus Clay and whether they impact its properties. The knowledge gained in Rheinau is important for understanding the properties of the Opalinus Clay, which is of relevance for all three potential siting regions (Jura Ost, Nördlich Lägern and Zürich Nordost). Preparatory work will start next week, and drilling will begin in summer.
In addition, Nagra is planning another borehole in the community of Bachs in the Nördlich Lägern siting region. Drill site construction will start as soon as approval has been granted. Whether this borehole will eventually be drilled or not depends on the results of the ongoing borehole investigations being conducted in Stadel in Canton Zürich. Nagra will make the final decision regarding the borehole in July. In the previously completed borehole in Bülach, Nagra drilled through a fossilised coral reef above the Opalinus Clay. This reef divides the region into two sections. The drill site in Bachs is being prepared so that, if necessary, the section without the reef can be investigated in greater detail.
Nagra expects to be able to announce which of the three potential siting regions is best suited for a deep geological repository by next year. The lead in the site selection process lies with the Federal Government, but the Federal Council and the Swiss Parliament will have the final say – or, if this decision is put to a national referendum, the Swiss voters themselves.
Contact: Patrick Studer, Head Nagra’s Media Office: 076 579 36 50, patrick.studer@nagra.ch
According to Swiss nuclear energy legislation, the producers of radioactive waste are responsible for its safe management and disposal. In 1972, the Federal Government and the nuclear power plant operators set up the National Cooperative for the Disposal of Radioactive Waste (Nagra) to perform this task. Nagra, which has its headquarters in Wettingen (AG), is the national technical competence centre in the field of deep geological disposal of radioactive waste.
Out of a strong sense of responsibility for the long-term protection of man and the environment, 130 employees are involved daily in performing this important work. The high level of competence is secured by targeted research programmes in two Swiss underground rock laboratories and intensive international collaboration.