What is the procedure for identifying the most suitable repository site?

The search for the most suitable site for a deep geological repository is regulated in the Federal Government’s Sectoral Plan process. In September 2022, Nagra proposed Nördlich Lägern as the site for a deep geological repository in Switzerland as it has the largest safety reserves.

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In order to protect humans and the environment, Switzerland will dispose of its radioactive waste in a deep geological repository. The search for the most suitable repository site is being carried out in line with the “Sectoral Plan for Deep Geological Repositories”. The Federal Government has the lead in this wide-ranging procedure. The decisive factor for the safety of a repository site is the stability of the underground conditions rather than of those at the surface. Political aspects play a subordinate role in determining the most suitable site; the only decisive factors are geology and operational safety. Socio-economic and spatial-planning aspects also play a role, but they are secondary to safety.

Affected parties can participate in the site selection process. The responsible Swiss Federal Office of Energy (SFOE) provides more information on regional participation.

A three-stage plan to identify the best site

At each stage, Nagra has been able to deepen its knowledge of the subsurface in the investigated regions, clarify uncertainties and make the project of the century of deep geological disposal more concrete. Nagra is developing the basis for the decision of the Federal Council on the proposed repository site.

Starting point for Stage 1: “blank map” of Switzerland

In Stage 1, Nagra determined which regions in Switzerland could be suitable for a deep geological repository. These siting regions were selected on the basis of safety and geological criteria.

The starting point was a “blank” map of Switzerland. This means that Nagra looked at potentially suitable regions and rock formations all over Switzerland. As a result, Nagra identified six potential siting regions, and the Federal Council decided that these should be investigated in more detail: Jura Ost, Jura-Südfuss, Nördlich Lägern, Südranden, Wellenberg and Zürich Nordost

Seismic measurements in Stage 2

In Stage 2, and in collaboration with the regions concerned, Nagra identified at least one siting area for the surface infrastructure in each of the six siting regions. To investigate the subsurface of the potential siting regions, one of the investigation methods used involved seismic measurements. In line with the federal authority stipulations, Nagra then conducted a safety-based comparison of all regions. At the end of Stage 2, the Federal Council determined the remaining siting regions to be Jura Ost (Canton Aargau), Nördlich Lägern (Cantons Aargau and Zürich) and Zürich Nordost (Cantons Thurgau and Zürich) along with the corresponding siting areas for the surface facility.

Siting regions in Stage 2

In-depth investigations in Stage 3, including deep boreholes

In Stage 3, Nagra investigated the three remaining siting regions in great detail. The investigation programme included previously conducted seismic measurements as well as Quaternary investigations and deep boreholes. The deep borehole investigations completed the already existing overall picture of the underground geological environment in the siting regions. Based on the results of these investigations and the safety-based comparison of the siting regions, Nagra announced in 2022 which siting region it considered best suited for a deep geological repository: Nördlich Lägern. Nagra then prepared a general licence application and submitted it to the federal authorities in November 2024.

Nagra’s siting proposal

Who does what?

Radioactive waste disposal is a collective, national task, and numerous stakeholders are involved in the process.

  • The Swiss Federal Office of Energy (SFOE) has the lead in the Sectoral Plan process, organises regional participation and informs the public about the progress of the work. It will also invite the cantons and responsible federal departments to take position on Nagra’s general licence application.
  • Nagra’s mandate is to plan and construct a deep geological repository. Numerous investigations have been conducted to build a solid scientific foundation. This foundation was also used for the Nördlich Lägern siting proposal communicated in September 2022. Nagra submitted the general licence application for a deep geological repository in Nördlich Lägern in November 2024.
  • The Swiss Federal Nuclear Safety Inspectorate (ENSI) supports the procedure in its role as regulatory authority and makes stipulations that Nagra has to comply with. It is also responsible for the safety-based evaluation and assessment of the siting proposal.
  • Communities, cantons, the public and interested organisations in the potential siting regions as well as in neighbouring Germany are involved in the site selection process and raise their concerns within the framework of regional participation. At public hearings, they can take position on Nagra’s siting proposals and the general licence application. Regional conferences form the core of regional participation and can also comment on the general licence application.
  • The Federal Council decides on licences for the construction of nuclear installations, which include geological repositories. A decision on Nagra’s general licence application is expected around 2029 and will be submitted to the Federal Assembly for approval.

Expert bodies – explained in simple terms (in german)

What is the next step?

The parliamentary decision on the general licence for a repository is subject to an optional national referendum. This means that a national referendum can be called for against the granting of the licence. In this case, the Swiss voters will have the final say (around 2031). Emplacement of low- and intermediate-level waste in a repository is foreseen to start around 2050, and emplacement in a high-level waste repository around 2060.