Nuclear fusion: With 200 lasers and a fuel capsule the size of a pepper, scientists are closer to harnessing this energy


By firing nearly 200 lasers at a cylinder containing a fuel capsule the size of a peppercorn, scientists in California have taken another step in the search for fusion energy, which, if harnessed, could provide the world with an almost limitless source of clean energy.

On a December morning last year, scientists at the National Ignition Facility at California’s Lawrence Livermore National Laboratory (LLNL) were able, for the first time in the world, to produce a nuclear fusion reaction that releases more energy than it uses, in a process called “ignition.”

They now say they have successfully replicated ignition at least three times this year, according to a December report by LLNL. This marks another important step in what could one day be an important solution to the global climate crisis, caused mainly by the burning of fossil fuels. fossil fuels.

Damien Jemison/LLNL

The NIF target chamber is where the magic happens – it creates temperatures of 100 million degrees and pressures extreme enough to compress the target to a density up to 100 times that of lead.

For decades, scientists have been trying to harness the power of fusion, essentially recreating the sun’s power on Earth.

Having achieved their historic net profit last year, the next important step was to prove that the process could be replicated.

Brian Appelbe, a research fellow at the Center for Inertial Fusion Research at Imperial College London, said the ability to replicate demonstrated the “robustness” of the process, showing that it can be achieved even when conditions such as the laser or fuel pellet are different.

Each experiment also offers an opportunity to study the physics of ignition in detail, Appelbe told CNN. “This provides valuable information for scientists to address the next challenge to be overcome: how to maximize the energy that can be obtained.”

Unlike nuclear fission—the process used in the world’s nuclear power plants today, which is generated by splitting atoms—nuclear fusion leaves no legacy of long-lived radioactive waste. As the climate crisis accelerates and the urgency to move away from planet-warming fossil fuels grows, the prospect of an abundant source of safe, clean energy is enticing.

Nuclear fusion, the reaction that powers the sun and other stars, involves smashing two or more atoms together to form a denser one, in a process that releases vast amounts of energy.

There are different ways to create energy from fusion, but at NIF scientists fire an array of nearly 200 lasers at a ball of hydrogen fuel inside a diamond capsule the size of a peppercorn, itself inside a gold cylinder. The lasers heat the outside of the cylinder, creating a series of very rapid explosions, generating large amounts of energy collected as heat.

The energy produced in December 2022 was small—about 2 megajoules were needed to drive the reaction, which released a total of 3.15 megajoules. enough to boil about 10 kettles of water. But it was enough to make a successful ignition and prove that laser fusion can generate energy.

Since then, scientists have done it several more times. On July 30, the NIF laser delivered just over 2 megajoules to the target, resulting in 3.88 megajoules of energy — their highest yield yet, according to the report. Two follow-up experiments in October also produced net gains.

“These results demonstrated the ability of NIF to consistently produce fusion energy at multi-megajoule levels,” the report said.

However, there is still a long way to go before nuclear fusion reaches the scale needed to power electricity grids and heating systems. The focus now is on building on the progress made and figuring out how to dramatically scale up fusion projects and significantly reduce costs.

At the COP28 climate summit in Dubai, US climate envoy John Kerry launched an international engagement plan involving more than 30 countries to boost nuclear fusion to help tackle the climate crisis.

“Fusion has the potential to revolutionize our world and change all the options before us and provide the world with abundant and clean energy without the harmful emissions of traditional energy sources,” Kerry said at the climate summit.

In December, the US Department of Energy announced a $42 million investment in a program bringing together multiple institutions, including LLNL, to create “hubs” focused on the advancement of fusion.

“Harnessing fusion energy is one of the greatest scientific and technological challenges of the 21st century,” US Energy Secretary Jennifer Granholm said in a statement. “We now have the confidence that it is not only possible, but likely that fusion energy can be a reality.”

Ella Nielsen and Renee Marsh contributed reporting

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