Nuclear fusion reactions produce nearly double the energy they consume

Scientists confirmed that a 2022 fusion reaction reached a historic milestone by releasing more energy than it put in, and subsequent tests yielded even better results. Says. The findings, now published in a series of papers, offer encouragement that fusion reactors will one day produce clean, abundant energy.

Today's nuclear power plants rely on nuclear fission reactions, in which atoms are shattered to release energy and small particles. Fusion works in reverse, pushing smaller particles together into larger atoms. The same process powers our sun.

Nuclear fusion can produce more energy without any of the radioactive waste that comes with nuclear fission, but science has yet to find a way to contain and control the process, let alone extract energy from it. Researchers and engineers couldn't find it for decades.

Experiments to do this using laser-irradiated capsules of deuterium and tritium fuel – a process called inertial confinement fusion (ICF) – began in 2011 at California's Lawrence Livermore National Laboratory (LLNL) . Initially, the energy released was only a fraction of the energy. The laser energy input was gradually increased and the experiment finally crossed the important break-even milestone on December 5, 2022. That reaction generated his 1.5 times the laser energy needed to kickstart.

One paper claims that the institute's National Ignition Facility (NIF) has seen even higher ratios in subsequent commissioning, peaking at 1.9 times its energy input on September 4, 2023. .

Richard Towne LLNL said it believes the team's checks and double-checks since the 2022 results have proven it was “not a flash in the pan” and there is still room for improvement.

Town said yields are likely to improve with the hardware currently in place at NIF, but things could move further if the lasers can be upgraded, which would take years. “A sledgehammer always comes in handy,” he says. “If I could get a bigger hammer, I think I could aim for a gain of about 10.”

But Town points out that NIF was never built as a prototype reactor and is not optimized for high yields. His main job is to provide critical research to the US nuclear weapons program.

Part of this research involves exposing the bomb's electronics and payload to the neutron irradiation that occurs during the ICF reaction to see if they would function in the event of an all-out nuclear war. The risk of electronic equipment failure was highlighted during a 2021 test when NIF opened fire, knocking out all lights throughout the site, plunging researchers into darkness. “These lights were not hardened, but you can imagine military components having to withstand much higher doses,” Town says.

This mission means that some of the project's research remains classified. Until the 1990s, even the concept of ICF was secret, Town says.

The announcement that ICF would reach break-even in 2022 raised hopes that fusion power is on the horizon, and this will be further strengthened by news that further progress has been made. However, there are some caveats.

First, the energy output is far below what is needed for a commercial reactor, producing barely enough to heat a bath. What's worse is that this ratio is calculated using the power of the laser, so for him to produce 2.1 megajoules of energy, the laser consumes her 500 trillion watts. That's more power than the output of the entire U.S. national power grid. Therefore, these experiments apply even in a very narrow sense.

martin freer The researchers, from the University of Birmingham in the UK, say these results certainly do not indicate that a practical fusion reactor can now be built. “Science still has work to do,” he says. “We don't know the answers to all of these, and we don't need researchers anymore.”

Freer says that as scientific experiments advance, they pose engineering challenges to create better materials and processes, which in turn enables better experiments and further progress. “Nuclear fusion could happen,” he says. “But the challenges we face are quite steep from a scientific perspective.”

Aneeka Khan The professor at the University of Manchester, UK, agrees that recent advances in fusion research are positive, but stresses that it will be decades before commercial power plants are operational, and that only global cooperation and He stressed that it depends on a concerted effort to train more people. field. She cautions against interpreting advances in fusion research as a possible solution to dealing with dependence on energy from fossil fuels.

“Fusion is already too slow to address the climate crisis. We are already facing the devastation of climate change on a global scale,” says Khan. “In the short term, we need to leverage existing low carbon technologies such as nuclear fission and renewables, and in the long term, invest in fusion to become part of a diverse low carbon energy mix. must commit to tackling the climate crisis.”