Sectoral Plan for Deep Geological Repositories (SGT)

The “Sectoral Plan for Deep Geological Repositories” specifies how sites for deep geological radwaste repositories are to be selected in Switzerland. Sectoral plans are used as tools in spatial and regional planning in order to organise cooperation between the Federal government and the cantons. The concept for the sectoral plan for deep geological repositories was developed by the Swiss Federal Office of Energy (SFOE) together with other agencies and organisations, and was approved by the Federal Council in 2008. The sectoral plan procedure is managed by the Swiss Federal Office of Energy (SFOE) and takes about ten years. This procedure allows a transparent and fair choice of locations, in three stages.

ENSI is responsible for reviewing and assessing the proposals for sites in terms of safety technology. The objective of storage in a deep geological repository is to protect people and the environment in the long term. The choice of locations is therefore based primarily on safety criteria (HSK 33/001). Other criteria such as social and economic aspects are of secondary importance. At the end of the procedure, the sites will be determined – either one for high-level radioactive waste (HLW) and another for low- and intermediate-level radioactive waste (L/ILW), or one site for all waste.

Stellung und Abhängigkeiten des Sachplans geologische Tiefenlager (Quelle: Sachplan Geologische Tiefenlager – Konzeptteil BFE, 2008, Abb. 3)
Stellung und Abhängigkeiten des Sachplans geologische Tiefenlager (Quelle: Sachplan Geologische Tiefenlager – Konzeptteil BFE, 2008, Abb. 3)

Specialist units involved

Documents on the sectoral plan

Stage 1: Selection of geological siting areas

On 17 October 2008, NAGRA (the National Cooperative for the Disposal of Radioactive Waste) submitted its proposal for suitable geological siting areas for deep geological repositories (NTB 08-03). It supplied reasons for its proposal in the form of additional reports (NTB 08-04, NTB 08-05, NTB 08-06). As the responsible supervisory authority of the Federal Government, ENSI reviewed the proposal for six siting areas to accommodate low- and intermediate-level radioactive waste (L/ILW) and three siting areas for high-level radioactive waste (HLW), with assistance from external experts. ENSI assessed all the siting areas as suitable and, in its expert report in January 2010, recommended that all the siting areas should be given further consideration in stage 2 of the Sectoral Plan for Deep Geological Repositories (ENSI 33/070, Fact Sheet as PDF, 1 MB / Fact Sheet on L/ILW and HLW Storage Facilities as PDF, 1 MB).

After a public hearing (hearing report), the report on the results of stage 1 was published by the Swiss Federal Office of Energy (SFOE) on 30 November 2011. On 1 December 2011, the Federal Council approved the report on the results of stage 1 and decided to incorporate the siting areas proposed by NAGRA and confirmed by the authorities into stage 2 of the sectoral plan.

Stage 1 was therefore completed.

Übersichtskarte der vorgeschlagenen geologischen Standortgebiete aus Etappe 1
Overview map showing the proposed geological siting areas from stage 1

For the L/ILW repository (low- and intermediate-level radioactive waste):

For the HLW storage facility (high-level radioactive waste):

Dokumente des ENSI zu Etappe 1

Experts’ reports commissioned by ENSI for stage 1

Stage 2: Selection of at least two sites

A deep geological repository also includes surface installations. These surface installations may be positioned within what is known as the planning perimeter, i.e. up to a distance of five kilometres around the geological siting areas proposed in stage 1. At the start of stage 2, NAGRA (the National Cooperative for the Disposal of Radioactive Waste) submitted potential siting proposals for these surface installations (NTB 11-01). At present, NAGRA is cooperating with the relevant cantons and regions to draw up plans for the precise siting and design of the surface installations (regional participation).

Based on the geological siting areas from stage 1, the parties obliged to undertake waste management must identify and evaluate potential sites for the underground storage areas and the surface installations, taking account of safety and technical feasibility as well as spatial planning and socio-economic aspects.

Of these sites, they propose at least two locations for the HLW storage facility and two for the L/ILW storage facility for incorporation into the sectoral plan as an interim result. At the same time, the parties obliged to undertake waste management amplify the criteria-based evaluation of safety and technical feasibility that was undertaken in stage 1 by adding quantitative provisional safety analyses as per ENSI’s requirements (ENSI 33/075). NAGRA had already clarified the additional investigations that are necessary in advance with ENSI (NTB 10-01, October 2010) in order to allow provisional safety analyses and a comparison of safety aspects. ENSI concluded that the available geological information, together with the further studies proposed by NAGRA and the additions required by ENSI, will be adequate for this purpose.

The selection is reviewed by the authorities (ENSI, the Expert Group on Nuclear Waste Disposal (EGT) and the Federal Nuclear Safety Commission (NSC)) and, if their assessment is positive, the selection is approved by the Federal Council and incorporated into the sectoral plan as an interim result.

What ENSI reviews

With support from the Expert Group on Nuclear Waste Disposal (EGT), ENSI reviews and assesses the selection made by the parties obliged to undertake waste management from the viewpoint of safety. The results of the provisional safety analyses are evaluated according to the safety requirements stated in ENSI Guideline G03 and Annexes I and III (the conceptual part of the sectoral plan). For each site, it also examines whether the available knowledge and any uncertainties allow a provisional safety analysis to be carried out. The geological data that are used (e.g. expansion of the host rock, hydraulic permeability, expected hydraulic gradients, geochemistry) must adequately reproduce the situation at the site and must take account of existing uncertainties. The result of this review is recorded by ENSI in an expert report. The Federal Nuclear Safety Commission (NSC) then draws up a comment on ENSI’s expert report. The Federal Office for Spatial Development (ARE) assesses the spatial planning aspects, while the Federal Office for the Environment (FOEN) reviews the environmental aspects

Ermittlung des in der Vergleichsmethode verwendeten charakteristischen Dosisintervalls für einen Tiefenlagerstandort. Quelle: siehe Konzeptteil BFE S. 72
Determination of the characteristic dose interval used in the comparative method for a deep geological repository site, source: conceptual part, SFOE p. 72

ENSI documents for stage 2

Expert reports commissioned by ENSI for stage 2

Stage 3: Selection of the site

The remaining sites must be examined in depth during stage 3, and site-specific geological knowledge must be amplified by means of geological investigations as necessary, so that a detailed comparison can be carried out from the safety viewpoint. More specific information is added to the repository projects, with the inclusion of the siting regions, and the socio-economic impacts are examined in depth. The parties obliged to undertake waste management propose the sites where deep geological repositories should be built (one for HLW and one for L/ILW), and they submit the general licence applications.

The general licence applications are reviewed by the responsible specialist units of the Federal government. Permanent protection of people and the environment must be ensured. The geological characteristics of the site play a key part. However, the required safety must be provided by the entire system (waste, technical barriers, surrounding natural barriers). ENSI Guideline G03 stipulates how the long-term safety of a deep geological repository can be achieved.

The Federal Nuclear Safety Commission (NSC) draws up comments on the export reports by ENSI