First permits issued for Swiss exploratory boreholes

21 August 2018

Switzerland's national radioactive waste disposal cooperative Nagra has been granted permits for carrying out the first three exploratory boreholes in its search for potential sites to host two geological repositories.

Proposed sites for Switzerland's radioactive waste repositories (Image: SFOE/swisstopo)

During 2016 and 2017, Nagra submitted a total of 22 applications for exploratory drilling to the Swiss Federal Office of Energy. These were for eight boreholes each in the Jura Ost and Zürich Nordost regions and six in the Nördlich Lägern region. Each application is subject to a separate approval procedure.

On 17 August, Switzerland's Department of the Environment, Transport, Energy and Communication (DETEC) granted permits for the first three boreholes. These are the Bülach (NSG 17-02) exploration well in the Nördlich Lägern site area and the Trüllikon 1 (NSG 16-11) and Marthalen (NSG 16-15) wells in Zürich Nordost. DETEC said decisions for the other applications will be issued in the coming weeks and months.

Nagra plans to carry out exploratory drillings from 2019 onwards to examine the geological subsoil in the potential repository site locations. DETEC said Nagra is not expected to carry out all 22 requested exploratory drillings, noting that early tests results will determine further drilling plans.

Six sites were proposed in November 2011 during the first stage of the process for selecting sites for two repositories: one for low- and intermediate-level waste, the other for high-level waste. Nagra proposed in January 2015 that further investigations be carried out at the proposed siting regions of Zürich Nordost and Jura Ost in the third and final stage of the selection process. It said the four other regions under consideration in the second stage - Südranden, Nördlich Lägern, Jura-Südfuss and Wellenberg - would be placed in reserve. However, in December 2016, the Swiss Federal Nuclear Safety Inspectorate proposed that the Nördlich Lägern region also be included in the final stage. The Federal Council is expected to decide by the end of this year whether to agree with the location areas proposed by Nagra for consideration in the third stage.

Based on the results of the exploratory boreholes, Nagra is expected to announce around 2022 the sites for which it will prepare general licence applications for the construction of the two repositories. A definitive site selection and the decision of the Federal Council on the general licence – and with this the end of the third stage of the selection process - is expected by 2029. The decision of the Federal Council on the general licence has to be approved by parliament and is subject to an optional national referendum, expected around 2031. The repository for low- and intermediate-level waste is expected to start operation around 2050 and the high-level waste repository around 2060.

The main source of Switzerland's radioactive waste is electricity production at the country's five nuclear power plants. A certain amount is also produced in the medical, industrial and research sectors. The combined total volume is around 100,000 cubic metres, of which about 90% is low- and intermediate-level waste.

Up until 2006, much of Switzerland's used nuclear fuel was sent overseas for reprocessing. High level waste, and used fuel from 2006 onwards, is mostly stored at a central interim storage at Wurenlingen. Nagra has been operating an underground research laboratory for a high-level waste repository at Grimsel since 1983.

Researched and written by World Nuclear News