The Wellenberg geological siting region (Cantons Nidwalden, Obwalden) is one of the six potential siting regions for a geological repository confirmed by the Federal Council. It offers a potential host rock formation in central Switzerland. Here, the marly limestones beneath the Eggeligrat form a large body of rock that would be suitable for disposal of low- and intermediate-level waste.
The geological siting area covers an area of around 16 square kilometres. The marl formations of the Helveticum are the preferred host rock; due to tectonic accumulation, they have a vertical thickness of more than one thousand metres.
Understanding of the spatial conditions is based on results from six deep boreholes, detailed geological mapping in the field and seismic surveys. The comparatively restricted lateral extent of the host formation is offset by its large vertical thickness. This configuration offers considerable flexibility in terms of the layout of the disposal caverns and tunnels.
Overall, the siting area is evaluated as being suitable.
The Federal Government has specified the criteria for site selection in the sectoral plan for deep geological repositories. Nagra's task was to evaluate siting areas using these criteria. The evaluation has shown Wellenberg to be a suitable site for a repository for low- and intermediate-level waste. Political analysis of the previous democratic decisions made by the people of Canton Nidwalden is a matter for the authorities and, ultimately, the Federal Council.
The underground installations for a deep geological repository for low- and intermediate-level waste in the marl formations of the Helveticum could be constructed in the area shown in green.
Canton Obwalden: Engelberg
Canton Nidwalden: Wolfenschiessen
Planning perimeter for surface facilities
The required surface infrastructure (e.g. the portal of the access tunnel) could also be located outside this siting region. Working together with the affected Cantons and representatives from Germany, the Federal Government has defined planning zones (so-called planning perimeters) that include these additional areas. The planning perimeter extends up to 5 km around the geological siting region and should have good road or rail access. Mountainous and hilly zones and protected natural areas are restricting factors. The Federal Office of Energy announced the planning perimeters in provisional form on 10th December 2009; these were approved by the Federal Council on 30th November 2011.
Additional communities within the planning perimeter (besides the siting communities):
Canton Nidwalden: Dallenwil, Oberdorf
|Geological profile from north-north-west to south-south-east through the Wellenberg siting region. The repository would be located mainly in the lilac-coloured zone (Palfris Formation, Vitznau Marls).||The borehole profile above shows the vertical sequence of rock formations in the siting region. The host rock is highlighted. |
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|At a media conference held by the Swiss Federal Office of Energy (SFOE), Nagra announces its proposals for potential siting areas for the surface facility. These will serve as the basis for discussions within the framework of regional participation.|
|The Federal Council decides to include the siting region Wellenberg in the further Sectoral Plan process. Stage 1 of the process is completed and Stage 2 initiated.|
|Start of the public consultation phase on Stage 1
of the site selection process for deep geological repositories. |
|The Swiss Federal Nuclear Safety Inspectorate (ENSI) approves Nagra's proposed siting regions following a review of safety and engineering feasibility aspects.|
|Announcement of the provisional planning perimeter by the Swiss Federal Office of Energy (SFOE).|
|Stans. Together with the ENSI and Nagra, the SFOE provides information on the proposals for geological siting regions.|
|Engelberg. Together with the ENSI and Nagra, the SFOE provides information on the proposals for geological siting regions.|
Announcement by the SFOE of the proposed siting regions for deep geological repositories.
The Federal Council approves the conceptual part of the sectoral plan for deep geological repositories.
The voters of Canton Nidwalden reject the concession granted by the cantonal government for an exploratory drift at Wellenberg.
Final report of the Wellenberg working groups set up by the Department of the Environment, Transport, Energy and Communications (technical and economics working groups).
Suspension of the general licence procedure for the Wellenberg site by the Federal Council. Setting up of working groups under the lead of a steering committee.
Completion of additional surface-based investigations at Wellenberg. Refusal of the Wellenberg concession application in a cantonal vote.
Founding of the Cooperative for Nuclear Waste Management Wellenberg (GNW). The community of Wolfenschiessen (Wellenberg) approves an agreement with GNW on compensation measures and participation of the local community in the GNW Cooperative. Submission of a general licence application for Wellenberg.
|Completion of the site investigations for low- and intermediate-level waste, comparative assessment of the results for the four sites, proposal of the Wellenberg site.|
The Federal Court declares the change in law of Canton Nidwalden (right of disposition over the deep underground environment) to be valid.
Boreholes drilled at Wellenberg.
Start of investigations at Wellenberg. The assembly of voters of Canton Nidwalden approves three initiatives on the right of disposition over the deep underground environment.
Recognition by the Federal Council of the feasibility and safety of disposing of low- and intermediate-level waste in Switzerland.
Submission of an exploration application for Wellenberg (Canton Nidwalden).
|Submission of Project Gewähr to the federal authorities (demonstration of the feasibility and safety of disposing of all types of radioactive waste in Switzerland). |