Geologisches Standortgebiet Jura Ost Bözberg Atommüll

Jura Ost – a potential siting region for a deep geological repository

The “Jura Ost” region is situated west of Brugg in Canton Aargau. Investigations show that the underground in this region can safely contain radioactive waste. Jura Ost is therefore a potential siting region for a deep geological repository.

Interactive map of Jura Ost, one of three potential siting regions

In the future, Switzerland will dispose of its radioactive waste in a deep geological repository. This will comprise both underground and surface facilities. The decision on where to construct the repository depends on geology. The radioactive waste will be safely enclosed in rock formations at a depth of several hundreds of metres for a very long time period. The most important rock formations are the Opalinus Clay and those lying directly above and below it. They can also be found in the Jura Ost region where they have favourable properties.

Jura Ost is one of three potential siting regions that we have been investigating in detail since 2008 within the framework of the Sectoral Plan for Deep Geological Repositories of the Federal Government. We now know which properties the rocks have and how much space is available for a repository. We work with the region in deciding where to locate the surface facilities. Aside from Jura Ost, Nördlich Lägern and Zürich Nordost are also potential siting regions. As part of the Sectoral Plan process, we compare these regions to identify which one is most suitable for a repository. In a few years, the Federal Council will decide where the repository will be constructed.

Overview: What would a repository in Jura Ost look like?

For the Jura Ost siting region located to the west of Brugg, we developed a repository project adapted to the region. This incorporates the insights from our geological investigations and the results of our collaboration with the region.

The geological siting region delineates the underground rock area suitable for the disposal of radioactive waste. Areas with geological fault zones are avoided for repository construction. By investigating the underground (particularly with 3D seismics), we were able to identify such fault zones. Priority is given to the investigation perimeter that includes the most suitable part of the rock area and is designated to host the emplacement rooms for the waste. For this reason, it was investigated in depth. The main underground connection area comprises the endpoint for accesses from the surface and the starting point for accesses to the emplacement rooms.

The auxiliary access facilities are located at surface level. The auxiliary access facility for ventilation lies within the blue perimeter and supplies the underground section of the repository with fresh air. The auxiliary access facility for operations (JO-B1) serves to transport building materials and people as well as to supply power and water. Just like the surface facility (JO-3+), the auxiliary access facilities form part of the surface infrastructure of a deep geological repository. In the surface facility, the waste is prepared for emplacement and then transported below ground.

Detailed information on the Jura Ost siting project (in German)

State-of-the-art investigation methods used to complete overall picture

The geological underground in Jura Ost was explored and characterised using numerous investigation methods, including seismics, Quaternary boreholes and deep boreholes.

Nagra and other companies have investigated the geological underground of Northern Switzerland using various methods. Points indicate borehole investigations whose data are included in the siting decision. Areas and lines indicate seismic surveys. The three potential siting regions for a deep geological repository are: Jura Ost (left), Nördlich Lägern (centre) and Zürich Nordost (right).

In winter 2015/16, we carried out large-scale 3D seismic measurements to obtain an image of the underground in Jura Ost. This method can be compared to medical ultrasound images or an echo sounder used on ships. The seismic images we obtained provided important information on the structure of the rock formations. We were also able to identify the presence of geological fault zones and assess the space available for a repository.

Seismische Messungen Standortgebiet Jura Ost
Vibration vehicles are used for seismic measurements. The vehicle shown in this picture was driving along the Geissberg close to the Besserstein castle ruins.

We drilled three deep boreholes in Jura Ost: Bözberg-1 and Bözberg-2 (both in 2020) and Riniken (1983 to 1984). These reached a depth of several hundred metres and went far below the Opalinus Clay that will host the waste. By drilling these boreholes, we were able to obtain samples from various rock layers and determine their properties. Investigations showed that the Opalinus Clay, but also the rock formations lying directly above and below it, are very tight. The deep boreholes also revealed the depth at which the individual layers are located.

Tiefbohrung Bözberg-1 der Nagra im Standortgebiet Jura Ost
Nagra was able to recover many rock samples from the Bözberg-1 deep borehole.

To provide long-term safety, the emplacement rooms of a deep geological repository that hold the waste must lie sufficiently deep below ground. Only then is the repository safe from erosion caused by rivers and glaciers. Traces of past erosion processes are also visible in the Jura Ost siting region where rivers have cut troughs into the rock. To learn more about past erosion processes and to develop future scenarios, we conducted Quaternary investigations. With these, we were able to investigate the topmost – and our planet’s most recent – rock layer located just beneath the surface. Quaternary investigations primarily include boreholes that are drilled to a depth ranging from a few dozen metres to around three hundred metres. In 2018, we drilled in Riniken (two boreholes), Untersiggenthal, Gebenstorf-Brüel and Gebenstorf-Vogelsang.

Quartärbohrung der Nagra in Riniken Standortgebiet Jura Ost
Nagra’s first Quaternary borehole in Riniken

With the most recent investigations, we were able to complement and complete the already existing knowledge of the geological underground in Jura Ost. We are now in possession of a comprehensive image of the geological underground. Based on this, we have been able to develop the Jura Ost repository project. We have also thoroughly investigated the other two potential siting regions, Nördlich Lägern and Zürich Nordost, and can now objectively compare the three regions with one another.

Collaboration on the site for the surface infrastructure

Where will the buildings at the surface and accesses for a deep geological repository eventually be constructed? These are the questions Nagra is addressing together with the siting regions. Our dialogue partners are the Jura Ost Regional Conference, Canton Aargau and representatives from neighbouring Germany. These can express their views on the proposals that we publish as a basis for collaboration and discussion. By collaborating from this early stage, the responsible Swiss Federal Office of Energy ensures that the needs of the Jura Ost siting region are considered to the greatest extent possible.

Vollversammlung der Regionalkonferenz Jura Ost
Members of the Jura Ost Regional Conference exchange information at a general assembly. Source: Jura Ost Regional Conference

Websites of the region’s representatives (in German)

In 2019, we published specific proposals for the Jura Ost region on what the surface infrastructure might look like in this region. The proposals are the result of previous collaboration with the region. Together with the other siting regions, the issue of where to place the encapsulation plant for spent fuel assemblies was also discussed. The Jura Ost Regional Conference, Canton Aargau and representatives from Germany have worked intensively on the placement of the surface infrastructure and have submitted their position statements. These form the basis for the further concretisation of the surface infrastructure with a view to the general licence application.

Position statements of the Jura Ost Regional Conference and Canton Aargau (in German)

Next steps

In 2022, we will announce which siting region we consider most suitable for a deep geological repository. We will then submit a general licence application for this region. Our work is conducted in line with federal authority stipulations as set out in the Sectoral Plan for Deep Geological Repositories. This forms the basis for the decision of the Federal Council, which will decide on the site around 2029 and submit its decision to the Federal Assembly for approval around 2030. Once the definite site has been confirmed, we will plan and construct the deep geological repository there.

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