Radioactive waste in Switzerland will be disposed of in a deep geological repository. While most components will be underground, the repository will also include a surface facility. This will form the gateway to the subsurface, where the actual repository will be located.
The most important structures will be the shaft head facility and the provisioning hall. Other buildings will also be required for the construction and operation of the repository as well as for related logistical purposes. The waste itself will be emplaced in deep underground caverns and drifts. Nagra’s siting proposal envisages constructing the surface facility for the repository at the Haberstal site in the community of Stadel in Canton Zürich.
Encapsulation plant for spent fuel assemblies at Zwilag interim storage facility
All solidified waste will be delivered to the surface facility from the interim storage facility. Low- and intermediate-level waste will be packaged in drums. These will be suitable for disposal, but before emplacing them underground, they will be further enclosed in concrete containers, and any remaining voids will be filled with cement.
Vitrified high-level waste and spent fuel assemblies will be transferred from transport and storage casks to disposal canisters, which will then be welded shut and inspected. These work steps will take place in the so-called encapsulation plant for spent fuel assemblies (BEVA). This encapsulation plant is to be constructed in Würenlingen at the site of the interim storage facility (see visualisation on the right). From there, the waste will be transported to the deep geological repository.
Making use of synergies in Würenlingen
The encapsulation plants do not necessarily have to be located at the entrance to the repository. Accordingly, Nagra’s siting proposal envisages constructing the encapsulation plant in Würenlingen at the site of the existing interim storage facility (Zwilag, photo left). This enables synergies – with the exception of the general licence application. As the encapsulation plant will be located at a different site from the repository, a separate general licence application is required.
In line with current planning, low- and intermediate-level waste will also be emplaced at the interim storage facility. As such a plant already exists, it only requires more storage capacity, which can be achieved by expanding the plant. Constructing the encapsulation plant for spent fuel assemblies at the Zwilag interim storage facility makes sense because the site is already the competence centre for the packaging of radioactive waste. The area would not have to be constructed from scratch, but merely expanded.
Work report NAB 20-14 discusses the advantages and disadvantages of various siting options for the encapsulation plant for high-level waste.
Read work report
How the site for the surface facility was decided
Underground rock formations determine where the emplacement rooms will be constructed. It makes sense to keep the access structures close to the deep geological repository. The search for a site for the surface facility involved close collaboration with the regions and cantons.
In its siting proposal, Nagra determined the site for the surface facility based on the recommendation of the region and Canton Zürich’s expert statement: the surface facility is to be constructed at the Haberstal site in the community of Stadel.
More information
Digital general licence application
Nagra has published all the documents relating to the general licence applications – three years earlier than required by law. The entire application documentation can be viewed digitally.
The path to a deep geological repository for Switzerland
Informal, yet informative brochure on the general licence applications.
Nagra’s siting proposal
What is Nagra proposing and why? Find everything you need to know about Nagra’s siting proposal in the report on the site selection decision.