HLW siting regions
At the beginning of 2015, Nagra proposed Zürich Nordost and Jura Ost as potential geological siting regions for a high-level waste (HLW) repository for further investigation in Stage 3. ENSI recommended at the end of 2016 that Nördlich Lägern should also be investigated further.
Current status of the site selection process
Nagra submitted its proposals for Stage 2 of the site selection process at the beginning of 2015, announcing which siting regions it planned to investigate in more detail in Stage 3.
The Swiss Federal Nuclear Safety Inspectorate (ENSI) reviewed the associated documentation and presented its initial conclusions in December 2016. ENSI agrees that the siting regions Südranden, Jura-Südfuss and Wellenberg should be placed in reserve; these were investigated for a repository for low- and intermediate-level waste (L/ILW). ENSI also agrees that the regions Zürich Nordost and Jura Ost should be investigated further in Stage 3. However, the safety authority is of the opinion that Nördlich Lägern should also be carried forward into Stage 3 as the reasons given for placing it in reserve are not sufficiently reliable. All three siting regions are suitable for a repository for high-level waste (HLW) and low- and intermediate-level waste (L/ILW), as well as for a combined repository.
The justification for ENSI's decision and its final evaluation are expected for spring 2017. Following a period of open consultation, the decision of the Federal Council on Stage 2 is expected for the end of 2018. Stage 3 of the process can then begin.
Work to date
Stage 1 complete
In the now completed Stage 1 of the Sectoral Plan process, and starting with a blank map of the whole of Switzerland, Nagra conducted a systematic search for potential siting regions for deep geological repositories. The search for sites (PDF in German) was based on pre-defined safety criteria, requirements relating to engineering feasibility and the steps defined in the Sectoral Plan for the selection of siting regions. It proceeded from large geologically suitable areas in the whole of Switzerland through preferred host rocks at suitable depth and with sufficient thickness to identification of potential geological siting regions.
Nagra proposed the following siting regions in autumn 2008: 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 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.
Nagra's proposals for 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.
Based on this comparison, in January 2015 Nagra submitted its proposals for siting regions for a HLW repository for further investigation in Stage 3: Zürich Nordost and Jura Ost. In its supporting documentation, Nagra notes that a safe HLW repository could be constructed in all three siting regions in the process. However, it recommended placing Nördlich Lägern in reserve on the grounds that the region has significant disadvantages in terms of safety compared with Zürich Nordost and Jura Ost. More detailed information is available in the small brochure «Siting regions for deep geological repositories – Nagra's proposals for Stage 3».
Supplementary documentation on the siting proposals
In November 2015, ENSI requested Nagra to submit additional documentation on the indicator «depth with respect to engineering feasibility». This was prepared and submitted in August 2016. Nagra adhered to its view that a safe HLW repository could be realised in Nördlich Lägern, but that constructing a repository at greater depth in the Opalinus Clay is very challenging. This was considered by Nagra to be a clear disadvantage in terms of safety.