Glass sensors being developed to withstand fusion environment

Led by Bangor University in partnership with Sheffield Hallam University, the researchers will identify whether glass sensors developed in 1960s could function in the extreme conditions of a nuclear fusion reaction. If not, the researchers will design and develop new glass sensors.

In December 2022, researchers at the US Department of Energy’s Lawrence Livermore National Laboratory (LLNL) delivered a net energy gain after attaining fusion ignition at LLNL’s National Ignition Facility . However, the move from experimental reactions to commercial power generation will require reliable monitoring in a fusion environment that can reach temperatures of 150-200 million degrees Centigrade and is populated with highly energetic fast-moving neutrons.

One way of monitoring a fusion reaction is to count the number of neutrons it gives off using scintillators that create a sparkle of light when struck by a neutron. By counting the flashes of light, it’s possible to calculate the number of neutrons and the amount of energy being produced, which helps to ensure everything is working properly.

According to Bangor University, the sensors currently used to calculate the energy output from fusion reactions tend to be cumbersome and awkward, and do not allow real-time and long term monitoring of the fusion process. For commercial nuclear fusion reactors to be run safely and efficiently, sensors will need to work reliably for years.

In a statement, project lead Dr Michael Rushton, from Bangor University’s Nuclear Futures Institute, 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 able to register radioactive particles were first developed in the 1960s, but they only work if particles are travelling relatively slowly. The Bangor University team is initially seeing if particles emanating from a fusion reaction could be slowed down sufficiently to allow these sensors to work based on their existing composition.

If this isn’t possible, they will use machine learning approaches to identify new configurations of glass that could be effective in the conditions found within nuclear fusion. The new sensor designs will then by manufactured at Sheffield Hallam University.

The two-year research project is being funded through UK Research and Innovation’s Engineering and Physical Sciences Research Council. It involves Bangor and Sheffield Hallam Universities, the Birmingham University, 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.