Scientists at UKAEA researching the best materials for fusion power plants are set to benefit from a range of world-leading laboratories, after being awarded funding for key experiments.

Components used in future fusion devices must be strong enough to endure harsh environments for long periods of time. The materials will face a combination of high temperatures from the hot fusion fuel (known as plasma), and constant bombardment by neutrons carrying energy from the fusion reactions.

Image of detector experiment at the European Synchrotron Radiation Facility

Image of detector experiment at the European Synchrotron Radiation Facility

As part of its critical research into fusion materials, UKAEA has secured time for six different experiments at major science facilities around the world. All of them will seek to test the viability of certain materials to use inside a fusion machine such as ITER, STEP and DEMO. (ITER is the world’s largest international science megaproject, now being built in the South of France, which intends to demonstrate fusion power on an industrial scale; STEP is the UK’s compact fusion power plant design activity and DEMO is Europe’s ‘prototype’ fusion power station.)

The areas of research are as follows:

  • UKAEA scientists will measure the residual stress on materials composed of glass and metal (known as glass-metal diffusion bonds). The experimental team will use high-energy x-ray beams at the European Synchrotron Radiation Facility in Grenoble, France to do this.
  • Another project will discover more about the structure of joints between dissimilar metals. This will be at the Institut Laue-Langevin in France.
  • Scientists will seek to identify defects in potential plasma-facing materials – such as the exhaust components – using ultrasonic testing carried out at ENEA, Italy, and comparing it with neutron imaging through using a high-power accelerator at the Swiss Spallation Neutron Source (Paul Scherrer Institute).
  • Another neutron imaging beamline experiment has already been performed at the IMAT beamline (Imaging and Materials Science & Engineering) at the ISIS spallation neutron source at the Rutherford Appleton Laboratory, Harwell Campus, UK. The experimental team investigated defects on copper-tungsten plasma-facing components.
  • An experiment at the ISIS spallation neutron source will examine the macrostructural and microstructural changes due to the extreme thermal loads experienced by the divertor (the plasma exhaust region in a fusion machine) on future fusion devices like DEMO.
  • The sixth project will use fast neutron imaging for testing of large fusion components at the Los Alamos Neutron Science Center in the USA.

Triestino Minniti, physicist in UKAEA’s Fusion Technology team, said that the process of getting beamtime for various experiments was extremely competitive – a sign that the experiments offered valuable scientific information to both UKAEA and the wider research community.

“With all these beamline experiments I aim to contribute and push forward the understanding of how these materials and components might behave in a harsh environment – like the one expected inside a fusion power plant,” he said.

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