It was considered a “major scientific discovery” and, it seems, the rumor was true: on Tuesday, Lawrence Livermore National Laboratory scientists announced that they had achieved a net energy gain for the first time in a controlled synthesis experiment.

“We’ve taken the first steps toward a clean energy source that could change the world,” National Nuclear Security Administration Administrator Jill Hruby said at a press conference Tuesday.

The victory came at the National Combustion Facility at LLNL in San Francisco. The institute has long tried to control 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 big catch in these fusion experiments: the amount of energy used to achieve fusion was far greater than the energy expended. As part of the NIF mission, scientists have long hoped to achieve “ignition” where the power output is “greater than or equal to the laser drive power”.

Some experts doubt even such success It is possible With fusion reactors currently in operation. But slowly, the NIF moved forward. In August of last year, LLNL announced that it had approached this threshold by using 1.3 megajoules (a measure of energy) on a laser drive with 1.9 megajoules.

But on December 5, according to LLNL scientists, they managed to cross the threshold.

They reached the ignition.

The target unit at the National Combustion Facility.

Lawrence Livermore National Laboratory

In general, this success is cause for celebration. It is the culmination of decades of scientific research and further development. Although small enough to demonstrate this type of reactor, it is important to move forward. canin fact, Power generation.

“Achieving ignition in a controlled fusion experiment is an achievement that comes after more than 60 years of international research, development, engineering and testing,” Hruby said.

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

Still, a fully functional platform, connected to the grid and used to power homes and businesses, may be a few decades away.

“This is one ignition capsule at a time,” said LLNL Director Kim Budill. “You have to do a lot of things to realize commercial fusion energy. You have to be able to generate lots and lots of fusion ignition events per minute, and you have to have a robust drive system to enable that.”

So how did we get here? And what will the power of future integration hold?

Simulating the stars

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

Fusion is a reaction between the nuclei of atoms that occurs under extreme conditions, such as in stars. For example, the Sun is 75% hydrogen and due to the universal heat and pressure inside it, these hydrogen atoms are compressed together. Grinding To create helium atoms.

If atoms had feelings, it would be easy to say that they don’t specifically. such as Crushing together. It takes a lot of energy to do that. Stars are integrated powerhouses; Their gravity creates the perfect conditions for a self-sustaining fusion reaction, and they burn until all their fuel — those atoms — is used up.

This idea forms the basis of fusion reactors.

A man in a white jumpsuit adjusts something in a sort of cylindrical room under blue lights.  Metal pipes adorn both sides of the room.

A technician adjusts an optic inside a preamplifier support structure at Lawrence Livermore National Laboratory’s National Ignition Facility.

Damien Jamieson / Lawrence Livermore National Laboratory

Building a chamber that can artificially recreate the conditions in the sun would allow for an extremely green energy source. Fusion does not directly produce greenhouse gases such as carbon dioxide and methane, which contribute to global warming.

And crucially, a fusion reactor also doesn’t have the downsides of nuclear. laziness, The splitting of atoms used in nuclear bombs and reactors today.

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

The biggest integration test

The NIF, which spans about three football fields at LLNL, is the world’s most powerful “inertial confinement fusion” experiment.

In the center of the chamber sits the target: a device containing a “hohram” or small cylinder-shaped capsule. The capsule, about the size of a peppercorn, is filled with isotopes of hydrogen, deuterium and tritium, or DT fuel, for short. The NIF focuses all 192 beams on the target, creating a high-temperature plasma and initiating an implosion. As a result, DT fuel is exposed to high temperatures and pressures, fusing hydrogen isotopes into helium – and the consequence of the reaction is much more energy and the emission of neutrons.

You can think of this experiment as a brief simulation of star conditions.

A brass cylinder appears on the back of the tea, held in place by metal tools.

This metal container, called the hohlraum, holds the fuel capsule for the NIF tests.

Lawrence Livermore National Laboratory

The tricky part, however, is that it takes a ton of energy to start the reaction. Fully powering the laser system used by the NIF requires more than 400 megajoules – but only a small percentage. It really hits hohlraum with every shot of rays. In the past, the NIF has been able to hit targets well with around 2 megajoules from its lasers.

But on December 5, during a run, something changed.

“Last week, for the first time, they designed this experiment to keep the fusion fuel hot enough, dense enough, and spherical,” NNSA Deputy Administrator Marv Adams said during the conference. “And the laser generated more energy than it stored.”

In particular, scientists at NIF started the fusion reaction using about 2 megajoules of energy to drive the laser and were able to produce about 3 megajoules. Based on the definition of ignition used by the NIF, the measurement is exceeded during this short pulse.

You can also see that the increase in energy in a compound reaction is expressed by the variable, Q.

As with ignition, the Q value can mean different things for different experiments. But here it refers to the energy input from the laser and the energy output from the capsule. If Q = 1, scientists say they have found a “breakeven”, where energy is equal to energy.

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

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

“The calculation of energy gain only considers the energy that hits the target, and it is not [very large] said Patrick Burr, a nuclear engineer at the University of New South Wales.

NIF isn’t the only utility that pursues integration — and its inability to initiate the process isn’t the only way to get stuck. “The conventional approach is magnetically bound fusion,” says Richard Garrett, senior adviser for strategic projects at the Australian Nuclear Science and Technology Agency. These reactors use magnetic fields to control the fusion reaction in gas, typically in a giant, hollow donut reactor known as a tokamak.

Because those devices have a much lower density than NIF capsules, the temperature must rise above 100 million degrees. Garrett said he doesn’t expect the NIF results to accelerate tokamak fusion programs because, fundamentally, the two processes work differently.

However, significant progress is being made in magnetically confined fusion. For example, the ITER experiment under construction in France uses a tokamak and is expected to begin testing within the next decade. He has high goals, he aims to achieve more than Q 10 and to develop trade integration by 2050.

The future of integration

The experiment at NIF may be transformative for research, but it won’t immediately translate into a fusion energy revolution. This is not a power test. It’s a proof of concept.

This is a point worth paying attention to today, especially since integration has been touted as the solution to combating the climate crisis and reducing dependence on fossil fuels or the world’s energy problems. Building and using renewable energy to power homes and businesses is still a ways off — decades, conservative — and inherently dependent on technological improvements and investment in alternative energy sources.

By generating about 2.5 megajoules of energy Total The input of the laser system is more than 400 megajoules, which is really ineffective. And in the NIF test, there was a short heartbeat.

Aerial view of NIF's laser bay with lots of cables, blocks and other equipment.

A view of the NIF laser bay from above.

Damien Jamieson / Lawrence Livermore National Laboratory

Looking ahead, permanent, reliable, long-lasting grains will need to power pots, houses, or entire cities if this is to be sustainable.

Australian National University physicist Ken Baldwin said: “It is unlikely that fusion energy … will save us from climate change.” Fusion energy may be too late if we are to prevent a sharp increase in global average temperature.

In the next few years, another investment is coming from private companies interested in building tokamak fusion reactors. For example, UK-based Tokamak Energy is building a spherical tokamak reactor and aims to hit fracking in the middle of this decade.

Then there’s the Commonwealth Fusion Systems, spun out of MIT, which is said to generate about 400 megawatts of power by the 2030s, enough to power tens of thousands of homes. Modern nuclear power plants can produce about three times more.

And as CNET editor Stephen Shankland points out in a recent article, fusion reactors must also compete with solar and wind power — so even with today’s revelations, fusion power remains in the experimental stages of its existence.

But now we can cast one eye into the future.

It may not stop extreme climate change, but it will use its full potential to provide an unlimited supply of energy for generations to come. It’s one thing to think about future energy sources on Earth and how they will be used, but our eyes may be on the horizon – deep space travel could use fusion reactors that explode beyond the gravitational pull of our Sun. Something that helped us learn about fusion reactions and into interstellar space.

Perhaps then, on December 5, 2022, we will remember the first small step into the places we once dared.

Correction, 8:44 a.m. PT: This article originally misstated the amount of energy involved in a combination reaction. The NIF generated the lasers at around 2 megajoules, resulting in an output of 3 megajoules.

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