Procedure

Decommissioning and disposal

Responsibility and duties

The owners of Swiss nuclear facilities are legally obliged to dismantle their facilities after decommissioning and to dispose of all radioactive waste safely. They bear all costs associated with decommissioning and disposal.

Decommissioning includes all activities up to the release of the nuclear facilities from the Nuclear Energy Act (KEG). The disposal obligation ends when the waste has been emplaced in the deep geological repository and the financial resources for the subsequent monitoring phase and any closure of the repository have been secured.

Decommissioning project and preparation for dismantling

For the definitive decommissioning of a nuclear facility, the owners draw up a decommissioning project while the plant is still in operation and submit it to the Swiss Federal Office of Energy (SFOE). Once the documents have been successfully reviewed by the Swiss Federal Nuclear Safety Inspectorate (ENSI), the responsible Department of the Environment, Transport, Energy and Communications (DETEC) issues the decommissioning order.

If a nuclear power plant is shut down and no longer generates electricity, power operation is considered to be permanently discontinued. Subsequent operation is then established and the plant is prepared for decommissioning. Once this has been completed and the legally binding decommissioning order has been issued, the plant can be taken out of operation for good.

Nuclear and conventional decommissioning

Nuclear dismantling is carried out from the inside out. The first step is to remove the fuel elements from the plant. As the deep geological repository is not yet in operation, they are safely stored in the central interim storage facility (Zwilag) in Würenlingen (AG) or in the Beznau interim storage facility (Zwibez).

Parallel to the removal of the fuel assemblies, the first systems and plant components that are no longer required are decommissioned, dismantled and removed from the nuclear power plant. During dismantling, the non-radioactive components are sorted out and recycled or disposed of like conventional waste.

Components on which radioactive substances have been deposited are decontaminated before they are also recycled or disposed of. In the end, only a few percent of all dismantling material is stored as low- or intermediate-level waste.

Around six to eight years after the removal of the fuel elements, the plant, which is currently being dismantled, is free of radioactive material. Once this has been confirmed by ENSI, the site of the former nuclear power plant is considered a normal industrial site. Conventional dismantling begins with the approval. The entire decommissioning process, from the final cessation of power operation and preparation, through nuclear and conventional dismantling to conversion or near-natural reuse, takes twelve to fifteen years according to current knowledge.

Waste disposal

Radioactive waste is disposed of independently of the operation, post-operation and decommissioning of a nuclear power plant. Spent high-level fuel elements and low- and intermediate-level waste are temporarily stored in the Zwilag and Zwibez. Once the deep geological repository has been commissioned, the waste is gradually transferred to the underground storage chambers. According to the Nuclear Energy Act (KEG), it must be possible to retrieve the stored materials during the monitoring phase without great effort. The deep geological repository will then be permanently sealed.