A controlled fusion reaction has generated more energy than was put into the system for the first time, bringing viable fusion power another step closer to reality. For the first time on Earth, a controlled fusion reaction has generated more power than it requires to run, researchers have confirmed. The experiment is a major step towards commercial fusion power, but experts say there is still a vast engineering effort needed to increase efficiency and reduce cost. In an experiment on 5 December, the lab’s National Ignition Facility (NIF) fusion reactor generated a power output of 3.15 megajoules from a laser power output of 2.05 megajoules – a gain of around 150 per cent. However, this is far outweighed by the roughly 300 megajoules drawn from the electrical grid to power the lasers in the first place. There are two main research approaches aiming to achieve viable nuclear fusion. One uses magnetic fields to contain a plasma, while the other uses lasers. NIF uses the second approach, known as inertial confinement fusion (ICF), where a tiny capsule containing hydrogen fuel is blasted with lasers, causing it to heat up and rapidly expand. This creates an equal and opposite reaction inwards, compressing the fuel. The nuclei of hydrogen atoms then fuse together to form heavier elements and some of their mass is released as energy – just as it is in the sun. Today’s announcement confirms that researchers have not only reached the crucial break-even milestone, but surpassed it. During the press conference, Jean-Michel Di-Nicola at LLNL said that at peak power – which NIF only achieves for a few billionths of a second – the lasers draw 500 trillion watts, which is more power than output by the entire US national grid. Jeremy Chittenden at Imperial College London says the experiment is a historic moment for fusion research. “It’s a major vindication of the approach that we’ve been trying, for ICF, for nigh on 50 years. It’s very significant.” Most fusion investment is currently poured into the alternative approach of magnetic confinement, in particular a reactor design called a tokamak. The Joint European Torus (JET) reactor near Oxford, UK, began operating in 1983. When running, it is the hottest point in the solar system, reaching 150 million°C (270 million°F). Earlier this year, JET sustained a reaction for 5 seconds, producing a record 59 megajoules of heat energy. A larger and more modern replacement, the International Thermonuclear Experimental Reactor (ITER) in France, is nearing completion and its first experiments are due to start in 2025. Another reactor using the same design, the Korea Superconducting Tokamak Advanced Research (KSTAR) device, recently managed to sustain a reaction for 30 seconds at temperatures in excess of 100 million°C. https://lnkd.in/gYgr3wf7