After a 12-month engineering pause, Culham’s Materials Detritiation Facility (MDF) operations have restarted after an upgrade. Outputs have already contributed towards groundbreaking research into materials 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 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 within the materials, and how much thermal treatment can remove it, 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. On initial removal from JET, these materials are classified as Intermediate Level Waste. By removing tritium, they can be reclassified as Low Level Waste. This is up to 10 times less expensive to dispose of. It can even 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 is a significant step forward in capability. Experimental trials on tiles and components removed from JET in late 2024 showed treatment is possible without prior disassembly. The trials also demonstrated simultaneous mixed material streams processing. This replicates 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.
The process gas stream carries tritium released during heating from the furnace. It passes through a catalyst that converts gaseous tritium species into tritiated water, enabling its efficient capture.
Once the furnace is cool, the thermally treated contents are taken out and subjected to destructive sampling for further analysis.
In addition to thermal treatment, analysis of gram-scale samples from JET will determine concentrations of other radionuclides. This will also 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. This demonstrates that fusion decommissioning can be safe, responsible and effective.
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.