Swiss progress7 April 2017
Switzerland’s search for deep geological repository sites is about to enter the final stage. Detailed investigations could start next year, with a final decision by 2031.
In December, Switzerland’s National Cooperative for the Disposal of Radioactive Waste (Nagra) submitted an updated plan for its radioactive waste disposal programme to federal authorities. The plan, which was first approved in 2008, is updated every five years.
The latest document outlines the procedures for planning, constructing and operating a deep geological repository; includes details on the origin, types and volumes of radioactive waste; and gives an overview of the expected design and layout of the proposed radioactive waste repositories.
According to the plan, Nagra intends to examine two regions Zürich Nordost and Jura Ost in the third stage of its site search for a deep geological repository.
The Swiss Federal Office of Energy (SFOE), the Federal Nuclear Safety Inspectorate (Ensi) and the Nuclear Safety Commission (NSC) are responsible for reviewing the 2016 Waste Management Programme. The Federal Council is expected to decide on the programme in early 2019, after a period of public consultation.
Site selection so far
The Swiss radioactive waste management concept assumes two geological repositories: one for low- and intermediate-level waste (L/ILW) and one for high-level waste (HLW). These repositories could be built at two different locations, or at the same site with some shared access.
Switzerland is pursuing a three-stage site selection process, which has been regulated by the Sectoral Plan for Deep Geological Repositories since 2008.
During stage 1, Nagra proposed six regions that are suited for a L/ILW repository (Südranden, Zürich Nordost, Nördlich Lägern, Jura Ost, Jura-Südfuss, Wellenberg) and three potential sites for a HLW repository (Zürich Nordost, Nördlich Lägern and Jura Ost). These regions were confirmed by the Federal Council in November 2011. In stage 2, working together with the siting regions, Nagra identified areas for the repository surface facilities and expanded its knowledge base through further geological investigations. Based on these assessments, in January 2015 Nagra submitted its proposals for two sites – Jura Ost and Zürich Nordost – to be investigated further. The plans were reviewed by the nuclear regulator, Ensi, and in September 2015, it asked for additional information relevant for the Nördlich Lägern site. Ensi asked Nagra to show whether construction at greater depth involves disadvantages in terms of safety and whether modifying the repository concept would be advantageous for such depths. Nagra had previously concluded that Nördlich Lägern has insufficient underground space in the preferred depth range and that there was “no possibility” of realising the repository at the optimum depth.
In response to Ensi’s request, Nagra looked at a range of concepts for disposal chambers and sealing sections at different depths. In August 2016, Dr. Piet Zuidema, a member of Nagra’s Executive Board said that the company’s analyses had shown that constructing a repository at great depth in the Opalinus Clay is “highly challenging”. Nagra believes that a depth greater than 600m for the L/ILW repository and 700m for the HLW repository would bring disadvantages with respect to safety and is therefore standing by its 2015 decision. “It is important for safety that we should give priority to conditions that are straightforward in terms of construction,” Zuidema said. However, pending Ensi’s review and in order to avoid further delays in the site selection process, Nagra decided that in addition to its two preferred sites it would carry out 3D seismic measurements in the Nördlich Lägern region and prepare applications for exploratory boreholes.
In February 2017, Nagra announced that it had completed seismic surveys of around 200km2 of land covering 53 communities in the three proposed siting regions. The aim of the measurements was to build up 3D images that allow reliable statements to be made about the geology and hence the long-term safety of a deep geological repository. The new findings allow the repository layout to be optimised.
What is next?
Authorities are currently reviewing the radioactive waste management plans. After a period of open consultation (in mid 2018), the federal government is expected to decide whether it will approve Nagra’s proposed locations for stage 3 (in early 2019).
Detailed investigations will be carried out in the regions selected, including further 3D seismic investigations and drilling activities. These will be used to prepare a detailed safety analysis for each proposed site. At the end of September 2016, Nagra applied to the SFOE for eight exploratory boreholes in each of the siting regions Jura Ost and Zürich Nordost. The boreholes will be used to investigate the geological and hydrogeological properties of the underground rock formations. In late February, Nagra said the plans for investigations in five communities in the Jura Ost region had been released for public inspection. Nagra expects the permits to be granted in autumn 2018.
Around 2021, Nagra is expected announce the sites (or site for a combined repository) for which a general licence application will be prepared and submitted. The surface infrastructure will be decided in cooperation with the siting regions. Nagra’s current plan assumes that the general licence applications will be submitted to the SFOE around 2024. The process is expected to end around 2029 with the final decision of the Federal Council and receipt of licences for the repositories. The decision then has to be approved by parliament and may be subject to a national referendum. The repository for L/ILW is expected to be operational around 2050, with the HLW facility entering operation after 2060, according to Nagra’s latest plan.
Piet Zuidema will be providing an update on Switzerland’s progress in storage, transportation, and disposal of spent fuel and HLW at the International High-Level Radioactive Waste Management conference in the USA on 9-13 April 2017