Uncle Sam plows $42M into nurturing fusion breakthrough

The US Department of Energy has released $42 million in seed funding to help research the nuclear fusion techniques successfully demonstrated at Lawrence Livermore National Laboratory last year.

The institution claimed a world-first in December 2022 when it produced 3.15 megajoules of fusion energy as output, exceeding the 2.05 megajoules delivered by the 192 lasers that kick-started the nuclear fusion reaction. The experiment was repeated in August this year.

The most recent experiment achieved a higher energy yield than the earlier breakthrough, the institution said.

The lab's National Ignition Facility (NIF) relies on laser fusion – as opposed to the magnetic confinement fusion approach used elsewhere – whereby 192 lasers focus on a cylindrical container or hohlraum. This tiny jar converts laser energy into X-rays to heat a tiny plasma capsule at its center. The capsule's high-density carbon (diamond) walls are 80 μm thick and house the nuclear fuel, a mixture of hydrogen isotopes deuterium and tritium.

The work is seen as a significant experimental breakthrough, but not one that would lead directly to the practical and commercial introduction of nuclear fusion to the world's energy supply chain, which needs to end its reliance on fossil fuels owing to their contribution to potentially devastating climate change.

The DoE money will be split between researchers at Colorado State University, the University of Rochester, and Lawrence Livermore National Laboratory.

Supported by the DoE Office of Fusion Energy Sciences (FES), the funding aims to boost a broad range of laser-based inertial fusion approaches. The research effort will be "focused more on the underlying technologies needed for any inertial fusion system," Scott Hsu, lead fusion coordinator at the Department of Energy, told the New York Times. To begin to consider the NIF technique as a practical energy source, it would need more powerful, reliable, and efficient lasers. Target hydrogen fuel would also need to be cheaper.

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For example, the University of Rochester hub aims to test a new laser that would fire directly on the hydrogen fuel rather than rely on intermediary X-rays, as with the most recent experiment. But the technology is temperamental and the smallest variation in laser light can destabilize the fusion reaction. Scientists hope to figure out how spreading the laser across a range of wavelengths might help results.

"Harnessing fusion energy is one of the greatest scientific and technological challenges of the 21st century," said US Secretary of Energy Jennifer Granholm in a statement. "We now have the confidence that it's not only possible, but probable, that fusion energy can be a reality. The scientists in these hubs will be the vanguard of game-changing and planet-saving breakthroughs."

Others have doubted whether nuclear fusion can be developed as a practical energy source to help transition away from fossil fuels.

Last year, experts speaking to the UK's Parliament detailed how fusion might one day be a feasible power source, but it was unlikely to come online in the time frame necessary to help the fight against climate change. ®