Fuel cycle

Decades of experience make us the world’s leading research organisation related to tritium and hydrogen science.

Technical discipline

UKAEA is a world-leading expert on tritium and deuterium, the hydrogen isotopes essential to fuel fusion machines and power plants.

Our experience and capabilities have developed from decades of managing tritium operations for the Joint European Torus (JET) fusion programme. We operate in fusion, fission and in adjacent hydrogen sectors, providing technical expertise, skills, infrastructure and equipment to stakeholders. We also offer technical support and consultancy to downstream users of tritium.

We provide world-class tritium training to support the growing demand for expertise and skills in the UK and internationally. We offer a range of opportunities for professionals, graduates, interns and PhD secondments.

Our Tritium Fuel Cycle team’s strategic goals are:

  • to accelerate tritium life cycle solutions by sharing and assimilating knowledge
  • deliver high-impact research and development programmes focused on accelerating the delivery of tritium life cycles
  • grow a community of specialists with world-leading tritium life cycle knowledge and experience
  • design, deliver, operate and decommission cutting-edge tritium life cycle facilities
  • develop productive collaborations with global leaders and experts in the tritium lifecycle and complementary fields
A fuel cycle facility at UK Atomic Energy Authority.

Capabilities

UKAEA-Eni H3AT Tritium Loop Facility

Tritium recovery and re-use will play a fundamental role in the supply and generation of the fuel in future fusion power plants and will be crucial in making the technology increasingly efficient.

The UKAEA-Eni H3AT Tritium Loop Facility is designed to serve as a world-class facility providing industry and academia the opportunity to study how to process, store and recycle tritium. The facility can also be used for the testing and validation of materials, equipment and sub-systems within a tritium environment.

UKAEA and Eni will collaborate to develop advanced technological solutions in fusion energy and related technologies, including skills transfer initiatives.

Eni will contribute to the H3AT project with its expertise in managing and developing large-scale projects, helping to de-risk its roadmap. This partnership combines UKAEA’s extensive expertise in fusion research and development with Eni’s established industrial-scale capabilities in plant engineering, commissioning, and operations.

The UKAEA-Eni H3AT Tritium Loop Facility, located at Culham Campus, will be complete in 2028.

Training

UKAEA’s world-leading Tritium Training Course is an ideal opportunity for anyone working on tritium systems or anything which comes into contact with tritium to learn from the expert team based at Culham Campus, Oxfordshire, UK.

Tritium Fundamentals

  • Chemistry of Tritium
  • Uses
  • Safety and Basic Confinement
  • Challenges

The Tritium Fuel Cycle

  • Fuel Cycles
  • Sub-systems
  • Future Devices and how Fuel Cycles change

Tritium Plant Key Concepts

  • Material Selection
  • Pumping and Vacuum
  • Measuring and Monitoring
  • Tritium Accountancy
  • Confinement Philosophies
  • Installation and Maintenance
  • Decommissioning and Waste
  • Safety Cases
  • Standards and Regulation

The day at Culham also includes a tour of the Active Gas Handling System, UKAEA’s tritium processing plant, which played a vital role in JET’s record-breaking campaigns and is still managing the tritium being off-gassed by the tokamak. 

This one-day, classroom-based course is applicable to:

  • Industry
  • Academia
  • Start-ups
  • Scientists
  • Engineers
  • Operators
  • Graduates
  • New starters
Contact us for more information about future courses

Research highlights

The fundamentals: Tritium interactions with materials

Some of our core research programmes concern tritium’s interactions with materials. Finding an effective hydrogen isotope separation system, and in ensuring that tritium permeation is kept to a minimum, are both essential in making any tritium fuel cycle efficient and thereby making as much of this precious element available as fuel.

EUROPA is a high temperature rig designed to increase the understanding of tritium permeation, and investigate how best this can be managed in many locations within a fuel cycle system.

The Mini Plasma Deposition Reactor successfully produced a world-first in an emerging new field in atomic energy by growing a diamond battery out of isotopically pure 14C methane from graphite from former nuclear reactors, presenting an opportunity to recycle 14C into micro-power diamond batteries.

The Palladium Membrane Reactor is a facility designed to clean hydrogen and hydrogen isotopes so that they can be used as a fuel.

DELPHI (Device for Exposure to Low-energy Plasma of Hydrogen Isotopes) is used to investigate the interaction of hydrogen isotopes with materials. Experimental results will be directly relevant to plasma-facing materials research and development within future fusion energy.

The THEIA project aims to test various nano-porous materials for a pressure-swing-adsorption based hydrogen isotope separation system.

Developing processes

Having effective and efficient processes are crucial for any experimental programme involving tritium, which has the properties of any other hydrogen isotope as well as radioactivity. Tritium Fuel Cycle has decades of experience of developing such processes, and is continuing to undertake research into the next generation of equipment which will be required throughout the sector.

JET’s Active Gas Handling System (AGHS) was designed to supply, recover, process and recirculate the hydrogen isotopes, including tritium, which were used by the torus during plasma science operations. It consists of a number of main process sub-systems and several ancillary sub-systems. While plasma research has now concluded, the AGHS remains critically important for JET’s decommissioning, managing the off-gassed tritium which is removed from the Torus during ventilation.

The Vacuum Pump Test Rig is an experimental project delivered in conjunction with STEP’s Fuel Cycle Team to advance the development of the Compound Cryopump (CCP), a key technology for STEP’s plant design. The role of the cryopump is to separate the exhaust gases created by the plasma. STEP’s CCP will allow the recirculation of deuterium and tritium back into the tokamak while seeded impurities and helium are sent to plasma exhaust processing.

Thermal Desorption Spectrometry (TDS) is used to measure hydrogen inventory. At Culham, the TDS comprises a vacuum chamber fitted with a mass spectrometer, a sample heater and a lock load system. It has been used to test small samples of beryllium and tungsten which have been taken from the JET vessel, measuring outgassing to determine the amount of tritium in the sample.

Four key areas must be considered when looking at tritium analytics: process control; environmental protection; safety; and non-proliferation. Each of these areas pose different challenges, which aim to be addressed using the HERA (Hydrogen Experiment for Real-Time Analysis) rig, which began its first tritium experiments in 2024.

Plant architecture

Drawing on decades of hands-on experience from operating the Joint European Torus (JET), our team provides specialised expertise in plant architecture for tritium fuel cycle systems, a cornerstone of fusion power delivery.

We design and model the full spatial and functional integration of tritium handling infrastructure, including:

  • fuel storage and inventory management
  • isotope separation and purification systems
  • detritiation and waste processing
  • tritium breeding loop integration
  • remote handling and containment strategies

Our approach combines deep operational insight with advanced digital modelling to optimise layout, safety, and maintainability across the entire tritium cycle. From concept design to delivery planning, we help fusion developers de-risk complex fuel systems and accelerate readiness for regulatory approval and commercial deployment.

With proven capability grounded in the UK’s leading fusion research facility, we’re enabling the next generation of fusion plants to handle tritium safely, efficiently, and at scale.

Waste and decommissioning

UKAEA has unparalleled experience in handling and managing tritiated waste as part of a holistic fuel cycle approach.

This includes developing cutting edge techniques for the decontamination and decommissioning of tritiated materials in a cost-effective and environmentally sustainable manner.

Recent research includes ascertaining the most efficient means of removing tritium from hard – Inconel, stainless steel, copper, beryllium and tungsten – and soft – PPE, plastics, etc – materials. The decommissioning of the Joint European Torus (JET) is also providing the Fuel Cycle team with hands-on experience of dismantling and size reducing complex components for further analysis.

There are a number of facilities available to support research and development, whether on behalf of the JET Decommissioning and Repurposing programme or third parties.

Culham Campus’s Tritium Analysis Laboratories use pyrolysis to analyse small samples (between 2g and 10g) of hard or soft waste.

The Materials Detritiation Facility (MDF) was built to thermally treat Intermediate Level Waste (ILW) accumulated during JET’s plasma operations, capturing tritium released from materials in water. The MDF Analysis Laboratory is designed to sample waste items before and after the thermal treatment to quantify and optimise the treatment process.

Case studies

Read our case studies.

Other case studies

US ITER

US ITER oversees the United States’ contribution to ITER, an international collaboration to demonstrate the scientific and technological feasibility of fusion energy. US ITER is investigating the use of new all-metal, tritium-compatible mechanical pumps to pump and transfer gas within ITER’s fuel cycle. US ITER worked closely with Eumeca, the manufacturer, to develop a 150 m3/hr scroll pump, a successor to the Normetex design used in JET’s Active Gas Handling System (AGHS). Eumeca’s device is currently the only suitable tritium-compatible pump technology able to perform this role and is therefore integral to ITER’s fuel cycle.   

The Tritium Fuel Cycle Division performed valuable hydrogen characterisation testing for two scroll pump prototypes with US ITER.  UKAEA’s Scroll Pump Investigation Rig for ITER Testing using hydrogen, which was designed, developed and built by the Tritium Fuel Cycle team together with the Product Engineering Unit, then helped to further qualify these pumps for use in the ITER vacuum system by validating and characterising the pump’s performance with hydrogen isotopes (protium and deuterium). The team designed and installed a new gas supply, mass flow metering station, exhaust vent and temporary 40kW cooling circuit as part of this testing.

UKAEA has extensive multi-disciplinary experience, technical expertise and capability in handling and managing the hydrogen isotopes that are crucial for fusion energy production. These capabilities have been developed over decades of research.

University of Bristol (Diamond Batteries)

Scientists and engineers from the UK Atomic Energy Authority (UKAEA) and the University of Bristol have successfully created the world’s first carbon-14 diamond battery.

This new type of battery has the potential to power devices for thousands of years, making it an incredibly long-lasting energy source.

The battery leverages the radioactive isotope, carbon-14, known for its use in radiocarbon dating, to produce a diamond battery.

Several game-changing applications are possible. Bio-compatible diamond batteries can be used in medical devices like ocular implants, hearing aids, and pacemakers, minimising the need for replacements and distress to patients.

Diamond batteries could also be used in extreme environments – both in space and on earth – where it is not practical to replace conventional batteries. The batteries could power active radio frequency (RF) tags where there is a need to identify and track devices either on earth or in space, such as spacecraft or payloads, for decades at a time, thus reducing costs and extending operational lifespan.

The carbon-14 diamond battery works by using the radioactive decay of carbon-14, which has a half-life of 5,700 years, to generate low levels of power. It functions similarly to solar panels, which convert light into electricity, but instead of using light particles (photons), they capture fast-moving electrons from within the diamond structure.

A team of scientists and engineers from both organisations worked together to build a plasma deposition rig, a specialised apparatus used for growing the diamond at UKAEA’s Culham Campus.  This development is the result, in part, of UKAEA’s work on fusion energy.

Equipment and facilities

UKAEA has a range of facilities to support the ongoing research and development into understanding tritiation of materials and how to recover tritium for use within the Fuel Cycle.

Tritium Analysis Laboratory

The Tritium Analysis Laboratory tests small waste samples using a pyrolyser within a fume cupboard. This incorporates a catalyst to ensure complete oxidation of tritium to HTO, and this tritiated water vapour is dissolved in bubblers, which in turn is analysed.

Materials Detritiation Facility

The Materials Detritiation Facility (MDF) processes material that is ILW due to its tritium content to down-categorise it to Low Level Waste (LLW) using a unique thermal treatment and tritium recovery technique. Materials are heated in a furnace with a constant air flow, with the tritium that is liberated captured in a water bubbler system.

FREYA

FREYA is an experiment to investigate the effectiveness of metal melting as a detritiation method for the metallic wastes produced from fusion machines. FREYA will build the understanding of this technique, as well as allowing for comparison with other thermal techniques to determine which is most effective at reducing tritium inventories in waste.

Plastic Fabrication Workshop

The Plastic Fabrication Workshop is home to our unique capability to design and manufacture bespoke containment solutions for hazardous environments including enclosures, protective covers or isolators. While born of a need to safely handle fusion materials and waste on the Culham site, our specialist competence and capability for designing containment enclosures has developed and enhanced into other protective areas and also for commercial use. 

Learn more about our Plastic Fabrication Workshop