Shedding Light on Irradiation-Induced Changes in Fusion Reactor Armour

A team led by Trinity’s Felix Hofmann have captured the structural evolution of tungsten due to intense irradiation.

Sustainable, low carbon energy production is essential for tackling climate change. Nuclear fusion has the potential to revolutionise the energy sector as a clean and sustainable power source. It occurs naturally inside stars, where the temperatures and pressures are high enough to fuse atoms together, and release energy in the process which we see as starlight. Advances in nuclear fusion reactor design bring this near-limitless energy source ever closer to being a viable power source on earth.

A key hurdle is that high-energy neutrons, which carry the fusion reaction energy, can damage the reactor wall during operation. New materials need to be designed for use as fusion reactor ‘armour’ that can withstand the intense irradiation and very high temperatures involved in the process.

The team led by Trinity Lecturer in Engineering Science Felix Hofmann at the University’s Department of Engineering Science worked with colleagues from the Culham Centre for Fusion Energy to conduct a study into tungsten, the main candidate material for fusion armour. The research paper, Observation of transient and asymptotic driven structural states of tungsten exposed to radiation, combines X-ray diffraction measurements and large scale atomistic simulations to examine how tungsten changes as a result of high energy particles.

Professor Felix Hofmann explains, ‘This insight into the delicate interplay of nanoscale defects is very important as tungsten is the main candidate material for fusion armour. Our results point to interesting new possibilities for designing more resilient materials with enhanced radiation resistance needed to make fusion power a reality. For the first time, we managed to capture the full structural evolution of tungsten, due to irradiation, from very low to extremely high doses.’

The research used X-ray micro diffraction to probe how extreme irradiation changes tungsten, the preferred material for fusion reactor armour. Detailed understanding of how irradiation changes armour materials is key for the design of future fusion reactors, to predict how components will degrade and evolve in service. It also opens the door to developing new, more radiation resistant materials essential for reliable and cost-effective long-term reactor operation. Designing such new materials is now the focus of the research team’s activities.