Nuclear for clean energy - 16th January 2023

After more than six decades, scientists have reached a milestone in harnessing energy from nuclear fusion. A ground-breaking experiment could pave the way for generating abundant supplies of clean energy.

In California, at the US National Ignition Facility, after teams of scientists fired lasers at a fuel capsule housed in a tiny gold cylinder, the heat and pressure of 2.05 megajoules resulted in hydrogen atoms fusing to create 3.15 megajoules of energy, a 50 percent gain. In basic terms, the fusion gave off more energy than was required in the heating process itself.

Nuclear fusion for power has been the stuff of science fiction for half a century. Rather than splitting atoms, fusion combines atoms and while this is something researchers have already achieved, the process previously consumed more energy than it delivered. Dr Arati Prabhakar, a White House official, commented, 'This is a tremendous example of what perseverance really can achieve.'

Current nuclear reactors utilise fission, where atoms are divided, but one significant drawback is the release of toxic radioactive waste which requires complicated and expensive disposal methods, such as encasing below ground or blasting into space.

By comparison, neither waste nor greenhouse gases are generated in nuclear fusion and as such, it could be science's silver bullet against climate change, though physicists warn against getting carried away.

'In some senses everything changes; in another, nothing changes,' said Justin Wark, physics professor at the University of Oxford, who added, "The obstacles to be overcome to make anything like a commercial reactor are huge."

To heat up and fire the lasers necessitates approximately 300 megajoules of energy, and they only fire once in 24 hours but to operate at a viable, commercial level, reactor lasers would need to trigger 10 times each second.

For Dr Mark Wenman, a reader in nuclear materials at Imperial College London, the experiment is undoubtedly momentous. Despite cautioning that 'challenges remain,' he described it as a 'fantastic scientific breakthrough – something we have not achieved in 70 years of trying.'

Although clean energy's still a long way off, this experiment's a game changer for fusion power.