The Geological siting regions for HLW
Nagra proposes Zürich Nordost and Jura Ost as potential geological siting regions for a high-level waste (HLW) repository for further investigation in Stage 3.
In the now completed Stage 1 of the Sectoral Plan process, and considering the whole of Switzerland, Nagra conducted a systematic search for potential siting regions for deep geological repositories. The search for sites was based on pre-defined safety criteria, requirements relating to engineering feasibility and the steps defined for the selection of siting regions and proceeded from large geologically suitable areas in the whole of Switzerland through preferred host rocks at suitable depth and with sufficient thickness to definition of potential geological siting regions.
In autumn 2008, Nagra proposed the following siting regions: Zürich Nordost, Nördlich Lägern and Jura Ost for deep geological repositories for HLW and L/ILW and, in addition to these, Südranden, Jura-Südfuss and Wellenberg for a L/ILW repository. The authorities and other technical bodies reviewed Nagra’s proposals and the Cantons, affected federal offices, neighbouring countries and interested organisations and individual persons then had the opportunity to express their views as part of a public consultation process. The Federal Council decided in 2011 to adopt all six proposed siting regions into the process, signalling the start of Stage 2.
In Stage 2 – and in collaboration with the regions and the Cantons – Nagra identified at least one siting area for the repository surface facility in each of the siting regions. The safety-based comparison of the geological siting regions in Stage 2 was carried out according to the requirements specified by the Federal Government. All three proposed siting regions fulfil the strict safety requirements and are suitable for the construction of a deep geological repository. However, a detailed comparison shows that there are decisive differences between the siting regions. The regions Zürich Nordost and Jura Ost offer more favourable conditions for a HLW repository compared to the Nördlich Lägern siting region (see table and histograms below). Based on these results, Nagra proposes the siting regions Zürich Nordost and Jura Ost as the regions for further investigation for a HLW repository in Stage 3. Nagra also proposes that the siting region Nördlich Lägern be placed in reserve for Stage 3.
Nagra’s proposals and documents are now being reviewed by the authorities and will then be opened for public consultation. At the end of Stage 2 (expected for 2018), the Federal Council will decide which siting regions will remain in the process.
Evaluation of the disposal perimeters in the geological siting regions for the HLW repository using the decision-relevant features and their associated indicators (after NTB 14-01).
For the HLW repository, Nagra proposes the siting regions Zürich Nordost and Jura Ost for further investigation in Stage 3 (after NTB 14-01).