Nuclear fusion is one of the most significant scientific and engineering challenges of our time. If successful, it could offer a future powered by clean, virtually limitless energy. Leading the charge in this effort is the UK Atomic Energy Authority (UKAEA). Through its Fusion Industry Programme (FIP), the UKAEA is helping lay the groundwork—both in infrastructure and technology—to make fusion a dependable source of energy.
Image Credit: IS Instruments
In May 2024, the UKAEA gave £9.6 million to six organizations, including two universities and four private companies, including IS-Instruments, to build projects that develop tools, technologies, and skills needed to speed up the commercialization of fusion energy.
The UK’s last remaining coal-fired power station closed in September 2024, although the country will need to decarbonize its electricity generation before STEP can be commissioned. As global power demand is expected to double by 2050, a mix of power sources will be needed to guarantee a consistent, sustainable supply. Fusion would be a valuable, non-varying source.
There is still a lot of work that needs to be done before nuclear fusion can become both a sustained reality and a commercially viable option. Its potential, however, should not be ignored in a society dedicated to mitigating climate change mitigation and reaching net-zero targets.
The UK, in its unique position as the host of JET, can make use of its leadership in fusion research to become a worldwide hub for fusion energy technology.
Why Fusion?
Fusion should be considered for many reasons, such as:
- Fuel Abundance: The fuels utilized in fusion reactions are practically inexhaustible. Deuterium is easily extracted from seawater, while tritium is produced by irradiating lithium.
- Reliability: Fusion is not reliant on external factors like wind/solar.
- High Fuel Efficiency: Fusion generates more energy per gram of fuel than any other process.
- No Chain Reaction: Fusion demands very specific (and high) temperature and pressure conditions to sustain reactions.
- Shorter-Lived Waste: Fusion waste is considerably less hazardous and has a shorter half-life than the waste generated by fission reactors.
There are still some key hurdles that need to be overcome before nuclear fusion can become a sustainable reality and a scalable solution to the world’s energy crisis.
Fusion demands temperatures of over 100 million degrees Celsius (for magnetic confinement) or high pressures of 100-1000 GPa. This poses the problem of creating and stably conserving these extreme conditions, the materials that contain them, and tracking the processes within them.
Another challenge concerns the fuel needed for fusion: tritium. A radioactive isotopologue of hydrogen, tritium is a vital fuel for nuclear fusion. However, naturally occurring tritium is hard to come by, so its production, storage, and management are critical for nuclear fusion power plants’ commercial viability.
Tritium raises challenges for measurement systems. Several techniques are typically necessary, like combining online and offline measurements. Chemical sensors are widely used. While they are not costly, they are not particularly accurate or specific.
While gas chromatography is both dependable and precise, the instruments are large, something that limits their usability. They are also complex and require specially trained personnel for operation and interpreting results.
Infrared absorption is non-invasive and precise; however, it is unable to differentiate diatomic H2, which does not have an IR line. Liquid Scintillation While counting promises a low detection limit, it also requires a large sample mass, is unable to measure H2 or D2, requires digestion into liquid form, and produces secondary waste.
The Role of Raman
Raman spectroscopy offers powerful capabilities for qualitative compositional analysis, thanks to its high selectivity. IS-Instruments, a specialist in Raman technology, focuses on designing deployable tools for on-site material and chemical analysis. For over five years, its flexible, modular systems have proven effective in challenging measurement environments.
As part of the Fusion Industry Program’s GRADE project, IS-Instruments is contributing to work on the fusion fuel cycle—specifically, the detection of hydrogen isotopes, with a focus on tritium.
The instrument used in this project has its origins in a 2014 collaboration between the Optoelectronic Research Centre (ORC) at the University of Southampton and Amentum. The ORC, the largest photonics research institute in the UK, is internationally recognized for its work in the field. Optical fibers developed and fabricated in Southampton have even been deployed on the Moon, Mars, and the International Space Station.
Amentum—formerly known as Jacobs Nuclear—is a global leader in advanced engineering and innovative technology across sectors, including energy, environment, space, defense, cyber, and more.
Working alongside both organizations, IS-Instruments conducted a feasibility study funded by Innovate UK to design and build a prototype benchtop spectrometer capable of analyzing gaseous samples.
While Raman spectroscopy is a well-established method for analyzing solids and liquids, applying it to gases presents notable challenges due to their diffuse nature. This collaboration explored the use of microstructured hollow-core fibers (HCF) to extend the laser-gas interaction path, enhancing sensitivity for gas-phase detection.
Through a series of Innovate UK-funded projects, the team successfully measured gases including N2, O2, and H2O, followed by C4, isopropanol (IPA), and CO. Building on this success, the instrument is now being further developed under the GRADE project to support tritium gas analysis within the fusion fuel cycle.
The first investigatory phase of GRADE concluded with successful, simultaneous measurements of hydrogen, deuterium, and deuterium hydride. The data demonstrated repeatable detection across a range of concentrations. When compared with existing literature and extrapolated, the results suggested that tritium could also be detected using the current instrument setup—prompting the transition to the next phase of development.
During this initial phase, IS-Instruments worked closely with Amentum to design a complete rig system capable of safely integrating the instrument into a tritiated environment.
The current focus is on verifying whether Gas Raman technology can reliably monitor tritium in real-time. This approach could also help track tritium as it undergoes beta decay—a process that emits low-energy beta particles which can interact with polymers, causing them to become brittle and less flexible.
Beta radiation can also generate gaseous byproducts, such as methane and small hydrocarbons, as polymers degrade and release tritiated compounds into the environment. This decay not only poses a potential environmental risk but also impacts fusion reactor components and operational safety. Because of its radioactive nature, testing any new monitoring equipment requires a specially designed containment area to ensure radiation resistance.
To support this, project partner Amentum has built a new tritium-specific glovebox. This facility enables testing of the spectrometer’s ability to detect tritium both as a pure component and as part of a mixture with H2, D2, and HD.
The research will also assess how HCFs perform in a tritiated environment—though previous studies have already shown that these fibers offer significantly greater radiation resistance than conventional silica fibers.1
Jessica Gabb, ISI project lead for GRADE, explained: “We have an ongoing collaboration with Amentum, and this special relationship has proven particularly beneficial when coordinating such a demanding and complex project with such a delicate instrument. We are also working with the Optoelectronic Research Centre at the University of Southampton to explore different filling techniques for the fibre to preserve the calibration values and improve the overall analysis time. Ultimately, the goal will be to use robotics to align the laser remotely, making the process safer for human operators.”
The instrument is now being tested at Amentum’s specialist facilities. The next stage will be to determine whether it is able to reliably and repeatedly identify tritium. This step will be finished prior to the project’s overall completion date at the end of March 2025.
This project has been supported by UK Atomic Energy Authority through the Fusion Industry Programme. The Fusion Industry Programme is stimulating the growth of the UK fusion ecosystem and preparing it for future global fusion powerplant market. More information about the Fusion Industry Programme can be found online: https://ccfe.ukaea.uk/programmes/fusion-industry-programme/
References and Further Reading
- Medaer, S.E.R., et al. (2023). Near-infrared radiation induced attenuation in nested anti-resonant nodeless fibers. Optics letters, (online) 48(23), pp.6224–6227. https://doi.org/10.1364/OL.504167.
This information has been sourced, reviewed and adapted from materials provided by IS Instruments.
For more information on this source, please visit IS Instruments.