Tungsten too brittle for nuclear fusion reactors

Materials World magazine
8 Jun 2018

Researchers find tungsten – a favoured choice of metal within nuclear reactors – is liable to become brittle, leading to failure. 

Scientists at the University of Huddersfield, UK, have been carrying out experiments that could aid the development of nuclear fusion reactors.

By simulating the damage caused by high-energy neutrons and alpha particles produced during the fusion process, the Huddersfield researchers have discovered that tungsten – a favoured choice of metal within the reactor as it has desirable properties of extreme hardness and exceptionally high melting temperature – is liable to become brittle, leading to failure.

‘At this moment in time, even though tungsten is a leading candidate, we don’t see how we can use it as a structural material. We can use it as a barrier, but not for anything structurally sound,’ said Dr Robert Harrison, who is a research fellow at the University of Huddersfield’s Electron Microscopy and Materials Analysis Research Group (EMMA).

The answer will be to develop a new alloy that combines tungsten with another material that can prevent its embrittlement from radiation damage and nuclear transmutation reactions, which would have significant safety implications for the operation of the reactor. 

By using both helium and tungsten ions to safely replicate the alpha particles created during a fusion reaction and the neutron bombardment, the EMMA researchers have been able to replicate the damage caused to tungsten. The findings are described in a new article in the journal Scripta Materialia.

Progress is being made towards the development of nuclear fusion, which fuses atoms rather than splits them as in a conventional fission reactor. Under construction in France is the International Experimental Fusion Reactor, which aims to be the first reactor that produces more energy than it consumes.