US scientists have achieved a significant nuclear fusion breakthrough in a bid to create a source of clean energy which is a major move towards combating the effects of climate change.
Physicists at the $3.5bn National Ignition Facility at the Lawrence Livermore National Laboratory (LLNL) in California have been experimenting for decades on realising the potential of nuclear fusion – a source of near-limitless clean energy.
Jill Hruby, of the National Nuclear Security Administration (NNSA), said the US had ‘taken the first tentative step towards a clean energy source that could revolutionise the world’.
Researchers confirmed they have overcome a major barrier – producing more energy from a fusion experiment than was necessary to ignite it. But they admit there is still some way to go before the technology has practical value.
LLNL director Dr Kim Budil said: ‘This is a historic achievement. Over the past 60 years thousands of people have contributed to this endeavour and it took real vision to get us here.’
Nuclear fusion works when two atoms combine to create on or more new atoms with less total mass, in order to release energy.
It’s the nuclear fusion reaction described by Einstein’s famous equation, E = mc2, where energy equals mass time the speed of light squared. And because the speed of light is enormous, converting just a tiny amount of mass into energy is similarly enormous.
It is the process which fuels the Sun and other stars, and doesn’t give off any greenhouse gas emissions so, therefore, doesn’t contribute to climate change.
This ignition is the opposite of nuclear fission, the technology currently used in nuclear power stations, where heavy atoms are split apart. This produces significant amounts of dangerous radioactive waste, unlike nuclear fusion which has negligible by-products.
But one of the challenges forcing and keeping the elements together in nuclear fusion requires very high temperatures and pressures. Until now, no experiment had managed to produce more energy from nuclear fusion than the amount put in to make it work.
Dr Marvin Adams, of the US National Nuclear Security Administration, said the laboratory’s 192 lasers had input 2.05 megajoules (MJ) of energy to the target, which had then produced 3.15 MJ of fusion energy output.
The amount of energy generated was tiny – just enough to boil around 15 to 20 kettles.
But experts say a fusion-powered future is one step closer. Dr Budil said: ‘With concerted efforts and investment, a few decades of research on the underlying technologies could put us in a position to build a power plant.’
Jeremy Chittenden, professor of plasma physics and co-director of the Centre for Inertial Fusion Studies at Imperial College London, called the experiment ‘a true breakthrough moment’.
‘It proves that the long sought-after goal, the “holy grail” of fusion, can indeed be achieved,’ he said.