A Big Boom in the Field of Energy: An Important Achievement in the American Fusion Experience

It has been described as a “major scientific breakthrough” and it appears to be The rumors were true: Scientists at Lawrence Livermore National Laboratory announced Tuesday that they have achieved, for the first time, a net increase in energy in a controlled fusion experiment.

“We have taken the first tentative steps toward a clean energy source that has the potential to revolutionize the world,” said Jill Hroby, director of the National Nuclear Security Administration, at a news conference Tuesday.

This victory comes thanks to the National Ignition Facility at LLNL in San Francisco. This facility has long tried to perfect nuclear fusion—the process that powers the sun and other stars—in an effort to harness the vast amounts of energy released during the reaction because, as Hruby points out, all that energy is “clean” energy.

Despite decades of effort, there was a major flaw in these fusion experiments: the amount of energy used to achieve fusion far exceeds the energy that comes out. As part of the NIF mission, scientists have long hoped to achieve “flaring,” where the power output is “greater than or equal to that of the laser engine.”

Some experts remained skeptical that such a feat was even possible With fusion reactors currently in operation. Slowly, however, the NIF pushed forward. In August last year, LLNL revealed its existence It came close to that limit by generating about 1.3 megajoules (a measure of energy) versus a laser engine using 1.9 megajoules.

But LLNL scientists say that on December 5th they crossed the line.

They achieved ignition.

Overall, this achievement is cause for celebration. It is the culmination of decades of scientific research and incremental progress. It’s an important, albeit small, step forward, to prove that this type of reactor works CanIn fact, Power generation.

“Achieving ignition in a controlled fusion experiment is a feat achieved after more than 60 years of research, development, engineering and experimentation globally,” Hroubi said.

“It’s a scientific milestone, but it’s also an engineering marvel,” Arati Prabhakar, director of policy in the White House Office of Science and Technology, said during the conference.

However, the fully operational platform, which is connected to the grid and used to power homes and businesses, is likely still a few decades away.

“This is one igniter capsule at a time,” said Kim Bodell, director of LLNL. “To achieve commercial fusion energy, you have to do several things. You have to be able to produce many fusion ignition events per minute, and you have to have a robust system of drivers to enable that.”

How did we get here then? And what does the future hold for fusion energy?

Star simulation

The basic physics of nuclear fusion has been well understood for nearly a century.

Fusion is an interaction between the nuclei of atoms that occurs under extreme conditions, such as those in stars. The sun, for example, is made up of about 75% hydrogen, and because of the exhaustive heat and pressure in its core, these hydrogen atoms are squeezing together, fusion to form helium atoms.

If atoms had feelings, it would be easy to say that they don’t in particular Such as They are crushed together. It takes a lot of energy to do that. Stars are fusion forces. Its gravity creates the perfect conditions for a self-sustaining fusion reaction and it continues to burn until all of its fuel – those atoms – has been used up.

This idea forms the basis of fusion reactors.

Building a unit that can artificially recreate the conditions inside the sun would allow for a very environmentally friendly energy source. Fusion does not directly produce greenhouse gases, such as carbon dioxide and methane, which contribute to global warming.

And most importantly, the fusion reactor also has no nuclear negatives nuclear fission, The fissile atoms used in bombs and nuclear reactors today.

In other words, a fusion power plant will not produce the radioactive waste associated with nuclear fission.

Great merger experience

NIF, which occupies an area of ​​about three football fields in the LLNL, is the world’s most powerful “self-confinement fusion” experience.

In the center of the chamber is a target: “hohlraum”, or cylindrical device containing a small capsule. The pod, about the size of a peppercorn, is filled with hydrogen isotopes deuterium and tritium, or DT fuel, for short. NIF focuses all 192 lasers on the target, producing intense heat that generates plasma and triggers an implosion. As a result, DT fuel is subjected to extreme temperatures and pressures, causing hydrogen isotopes to fuse into helium – and as a result of the reaction, excess energy is generated and neutrons are released.

You can think of this experiment as simulating the conditions of a star.

But the complicated part is that the reaction also requires a large amount of energy to get started. Powering the entire laser system used by NIF requires more than 400 megajoules — but only a small percentage actually hits Chamber with each launch of the beam. Previously, the NIF was able to consistently hit the target with about 2 megajoules from its lasers.

But on December 5, during one outing, something changed.

“Last week, for the first time, they designed this experiment so that fusion fuel stays hot enough, dense enough, and spinning enough long enough for it to ignite,” Marv Adams, deputy director at NNSA, said during the conference. “And it produced more energy than the laser could put in.”

More specifically, the scientists at NIF started the fusion reaction by using about 2 megajoules of energy to power the laser and managed to get about 3 megajoules out. Based on the primer definition used by NIF, the standard was passed during this short pulse.

You may also see that energy gain in a fusion reaction is denoted by the Q variable.

Like ignition, the Q value can refer to different things for different experiences. But here it refers to the power input from the laser versus the power output from the capsule. If Q = 1, scientists say they have achieved the “break-even point,” where energy in is equal to energy out.

The Q value for this run was, for context, about 1.5.

In the grand scheme of things, the power generated at this value of Q is just enough to boil water in a boiler.

“The energy gain calculation takes into account only the energy that hits the target, not the energy that hits the target [very large] “The energy consumption that goes into supporting infrastructure,” said Patrick Burr, a nuclear engineer at the University of New South Wales.

NIF isn’t the only facility chasing fusion — and inertial confinement isn’t the only way to start the process. “The most common method is magnetically confined fusion,” said Richard Jarrett, senior advisor for strategic projects at the Australian Nuclear Science and Technology Organization. These reactors use magnetic fields to control a gas fusion reaction, usually in a giant hollow donut reactor known as a tokamak.

These devices have much lower densities than NIF grains, so temperatures must be increased to more than 100 million degrees. Garrett said he doesn’t expect the NIF result to speed up tokamak fusion programs because the two processes work very differently.

However, significant progress is being made in confined magnetic fusion. For example, the ITER trial, under construction in France, uses tokamak and is expected to start testing in the next decade. It has lofty goals, aiming for a Q greater than 10 and developing trade integration by 2050.

The future of fusion

The experience at NIF may be transformative for research, but it won’t translate into that right away Fusion energy revolution. This is not a power generation experiment. It’s a proof of concept.

This is a point worth making today, especially since fusion is often touted as a way to combat the climate crisis and reduce dependence on fossil fuels or as a salve for the world’s energy woes. Building and using fusion energy to power homes and businesses is still decades away — decades, conservatively — and depends at its core on technological improvements and investment in alternative energy sources.

It generates about 2.5 megajoules of energy when it is the total The input from the laser system much higher than 400 mJ is, of course, not effective. And in the case of the NIF experiment, it was one short pulse.

Looking into the future, stable, reliable and long pulses will be needed if this is to become sustainable enough to power boilers, homes or entire cities.

“It is unlikely that fusion power will save us from climate change,” said Ken Baldwin, a physicist at the Australian National University. If we are to prevent the largest increases in global average temperature, the fusion power is likely to be a little too late.

Other investment will come from private companies seeking to operate the fusion reactors at tokamak in the next few years. For example, Tokamak Energy in the UK is building a spherical tokamak reactor and is aiming to break even by the middle of this decade.

Then there’s Commonwealth Fusion Systems, which spun off from MIT, which hopes to generate about 400 megawatts of power, enough for tens of thousands of homes, by 2030. Modern nuclear power plants can produce nearly three times as much.

and as CNET editor Stephen Shankland noted in a recent pieceFusion reactors will also need to compete with solar and wind power – so even with today’s revelations, fusion power remains firmly in the experimental phase of its existence.

But we can now take one look into the future.

It may not prevent the worst of climate change but, if harnessed to its full potential, could produce an almost unlimited supply of energy for future generations. It’s one thing to think about the future of energy on Earth and how it will be used, but our eyes may turn further – deep space travel could use fusion reactors that push us beyond the gravitational limits of our sun, the very thing that helped teach us On fusion reactions and in interstellar space.

Perhaps then, we remember December 5, 2022, as the first small step toward places we only once dared in a dream.

Correction for 8:44 a.m. PT: This article was initially wrong about the amount of energy in a fusion reaction. NIF powered the laser at about 2 megajoules and produced 3 megajoules as a result.