After a 12-month engineering pause, Culham’s Materials Detritiation Facility (MDF) has been upgraded and operations have restarted. Outputs have already contributed towards groundbreaking research into materials which have been removed from the Joint European Torus (JET) facility.
In the last three years of plasma operations, JET’s deuterium-tritium (DT) experiments resulted in residual tritium being retained within the tokamak’s walls and internal components. This reflected the isotope’s tendency to permeate into materials during high-powered fusion operations.
Understanding how much tritium is retained within the materials, and how much can be removed through thermal treatment, will be essential in developing a waste management strategy for JET Decommissioning and Repurposing (JDR).
By recovering tritium, UKAEA’s waste teams can greatly reduce disposal costs for materials such as tungsten, beryllium, Inconel, steel, copper and carbon-fibre composite. When they are initially removed from JET, these materials are classified as Intermediate Level Waste. By removing tritium, they can be reclassified as Low Level Waste, which is up to 10 times less expensive to dispose of, or even to be recycled into future fusion or fission machines.
In the early 2020s UKAEA waste experts undertook initial research on tritium removal from these materials at Culham’s tritium analysis laboratories.
The engineering work completed in the MDF represents a significant step forward in capability. Experimental trials on tiles and components removed from JET in late 2024 showed that they can be treated without prior disassembly. The trials also demonstrated that mixed material streams can also be processed simultaneously, replicating what would happen in an industrial-scale treatment facility.
To remove the retained tritium, the materials are heated to elevated temperatures in the MDF furnace under carefully controlled conditions designed to minimise oxidation. Limiting oxidation improves the efficiency of the process, reducing maintenance requirements, and helps to ensure the process remains safe and effective.
Tritium released during heating is carried from the furnace by the process gas stream and passed through a catalyst that converts gaseous tritium species into tritiated water, enabling its efficient capture.
Once the furnace has cooled, the thermally treated contents are taken out and subjected to destructive sampling for further analysis.
In addition to this thermal treatment, gram-scale samples from JET are being analysed to determine concentrations of other radionuclides and to quantify the amount of tritium remaining in the materials after treatment.
Xavier Lefebvre, Head of Waste, JET Decommissioning and Repurposing said:
This first-of-a-kind operation represents a significant milestone for JDR and would not have been possible without the dedication and the professionalism of the team which has delivered the sample retrieval runs in the MDF.
Successful processing of these samples gives us access to evidence that has simply not been available before, allowing us to better understand the nature of JET materials and the challenges associated with their long-term management.
The insights gained from this work have the potential to fundamentally influence the future waste strategy for JDR, reducing uncertainty and enabling more informed decisions on waste treatment, packaging, disposal routes and decommissioning planning. By improving the evidence base that underpins these decisions, the work may also demonstrate more proportionate waste management solutions and a better understanding of long-term liabilities.
It is an excellent example of how innovation, scientific ambition and operation can come together to deliver benefits not just for today’s programme, but for the future of fusion decommissioning. This achievement also highlights the unique capabilities we have developed at UKAEA and the critical role that facilities such as the MDF can play in addressing some of the most complex challenges facing fusion waste management.
By removing retained tritium from materials and reducing the volume of higher-activity waste requiring specialist management on site, the MDF directly supports UKAEA’s broader mission to protect people and the environment while demonstrating that fusion decommissioning can be done safely, responsibly and effectively.
As well as processing UKAEA’s legacy waste, the MDF is available for use by companies and organisations undertaking similar cutting-edge research in waste and materials management. Contact the Tritium Fuel Cycle team for more information.