U.K. delivers final cask of vitrified HLW to Germany

Completing an international commitment between the two countries, the United Kingdom's Nuclear Transport Solutions (NTS) delivered the third and final shipment of vitrified high-level radioactive waste to Germany, the U.K. Nuclear Decommissioning Authority (NDA) announced last week.

Seven CASTOR spent fuel casks, otherwise called flasks, containing stainless steel canisters of vitrified HLW were shipped from the Sellafield nuclear site in West Cumbria, England, to the state-run interim storage facility at Brokdorf, Germany. The waste resulted from the reprocessing and recycling at Sellafield of spent nuclear fuel that had previously been used in German nuclear power plants.

Background: Following the end of its international fuel reprocessing program in 2018, Sellafield began returning the resulting legacy waste to its country of origin through the U.K.'s vitrified residue returns program.

German nuclear power plant operators are contractually obliged to take back waste resulting from the reprocessing of their fuel elements abroad. The repatriation of waste is also underpinned by international agreements between Germany and the United Kingdom.

In 2020, the U.K.'s first shipment of six HLW casks was sent to Germany's interim storage facility at Biblis. The second shipment of seven casks to the Isar storage facility was completed in 2025.

In 2024, Orano completed a 13th and final rail shipment of vitrified HLW from France to Germany. That shipment was delivered to the intermediate storage facility at Philippsburg.

According to PreussenElektra, a subsidiary of the German utility E.ON, the distribution of reprocessed waste returning from abroad across multiple interim storage sites is based on a concept jointly agreed on by the German government and the nuclear utilities.

The return path: According to the NDA, the U.K.'s final shipment of HLW to Germany drew on the integrated capabilities of NTS and the wider NDA, combining rail, maritime, security, engineering, and regulatory expertise to complete the complex mission.

The seven casks, each weighing more than 100 tons, were transported via rail from Sellafield to the port town of Barrow, where they were loaded onto Pacific Nuclear Transport Ltd.'s vessel Pacific Grebe for the sea journey to Germany.

According to PreussenElektra, Pacific Grebe arrived at the northern German port of Brunsbüttel on June 16, and the seven casks were unloaded and transported to the Brokdorf facility on June 17.

The shipment involved NTS working in partnership with Sellafield Ltd., Orano-NCS, and German nuclear waste management services providers GNS Gesellschaft für Nuklear-Service and BGZ Gesellschaft für Zwischenlagerung.

Quotes: "This is a significant moment in the delivery of our mission; it marks the completion of our obligation to repatriate this waste, reducing the U.K.'s long term nuclear liabilities and delivering on government policy commitments," said NDA CEO David Peattie. "This has been a complex, multiyear effort, delivered through strong collaboration across the NDA group and is a testament to our world-leading nuclear expertise and capabilities."

Sellafield Ltd. CEO Euan Hutton added, "As consignor, Sellafield has held responsibility for this material throughout the return program, from vitrifying the waste into a stable glass form and safely storing it on-site, through to preparing it for transport and working with our partners to ensure its successful delivery."