The return transport of radioactive waste from reprocessing in Sellafield, England, to the BGZ interim storage facility at the Isar site has been completed: On 03 April, the seven transport and storage casks containing the vitrified waste arrived safely at their destination. The transport via sea and rail proceeded without incident. The BGZ will now store the casks in the interim storage facility in accordance with the requirements of the storage license issued by BASE; this is monitored by the Bavarian Ministry of the Environment as the competent nuclear supervisory authority.

The producers of this waste are the operators of German nuclear power plants, who transported irradiated fuel elements to France (La Hague) and Great Britain (Sellafield) for reprocessing until 2005. The return of the German waste is binding under international law.

Germany took back the last vitrified waste from reprocessing in France in November 2024. From Great Britain, in addition to the now completed transport of seven casks to the Isar site, six casks were most recently brought to Biblis in 2020. To fulfil international legal obligations towards the United Kingdom, a final transport of seven casks from Sellafield to Brokdorf is required. BASE licensed the storage at the on-site interim storage facility there in March 2024. The required transport license was applied for in 2024; BASE has not yet reached a decision on the application. The Federal Government plans to complete the return of the waste from the United Kingdom in 2026.