Glass sensors could make commercial nuclear fusion viable

The team's objective is to determine the feasibility of using glass sensors developed in the 1960s in the harsh environment of a nuclear fusion reaction. If it proves unviable, the researchers will proceed to create novel glass sensors.

In December 2022, the United States researchers achieved a breakthrough by generating more energy through nuclear fusion than the initial input. This success has opened up exciting possibilities for commercial viability and abundant clean energy. However, reliable monitoring is a crucial requirement to transition from experimental reactions to commercial power generation. The major hurdle in this regard is dealing with extreme conditions created during fusion reactions, such as temperatures ranging from 150-200 million degrees Celsius and highly energetic, fast-moving neutrons.

Counting the number of neutrons emitted through scintillators is a method for monitoring fusion reactions. These scintillators are composed of material that generates a flash of light every time it is struck by a neutron. By tallying these flashes, one can determine the number of neutrons produced and the energy generated, which aids in verifying that everything is functioning as planned.

Although scintillators are commonly used, they are primarily crafted from crystal or polymer materials that have size and shape limitations or are challenging to produce. They also lack the durability needed to withstand the harsh conditions generated by fusion reactions. Additionally, the current sensors utilised to determine energy output from fusion reactions are cumbersome and incapable of real-time and long-term monitoring of the process. To ensure safe and efficient operation of commercial nuclear fusion reactors, dependable sensors must be available for extended periods.

Dr Michael Rushton from Bangor University’s Nuclear Futures Institute is leading the new project. He said: “Glass has intrinsic radiation tolerance, so can survive well in very harsh conditions. It also has the advantage that it can be made in very different shapes, from fibres to plates which means sensors can be made for a range of situations within a reactor. And it’s fairly low cost to manufacture. We also hope to be able to ‘tune’ the sensors to work with different types of radioactive particle, so they may also be used for other applications, such as airport or medical scanners.”

Glass sensors capable of detecting radioactive particles were created in the 1960s, but they are only effective for slower-moving particles. The researchers at Bangor University are currently exploring the potential for these sensors to detect particles from a fusion reaction by slowing them down. If this is not feasible, the team will employ machine learning methods to identify alternative glass configurations that can function effectively under nuclear fusion conditions. Once developed, the new sensor designs will be manufactured by their collaborators at Sheffield Hallam University.

Professor Paul Bingham from Sheffield Hallam University said: “This research will develop an entirely new range of glass-based sensors for some of the most extreme environments on Earth. This means it could not only help accelerate safe development and deployment of fusion energy technologies, but also have wide-ranging applications in other fields in the future.”

The two-year research project is funded through UK Research and Innovation’s Engineering and Physical Sciences Research Council. It involves Bangor and Sheffield Hallam Universities, the University of Birmingham, the ISIS Neutron and Muon Source at the Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory as well as a number of commercial partners.