What is nuclear fusion on Earth – and when will we use it?

Nuclear fusion is back in the news. This week, the U.S. Department of Energy announced what it calls a “significant scientific breakthrough” in fusion power research: for the first time, a fusion experiment has produced more energy than was used to start the reaction. It’s not the first time we’ve heard of fusion progress. There have been decades of headlines highlighting breakthroughs large and small, often implying that we are closer than ever to producing all the clean energy we will ever need from nuclear fusion.

“A major scientific breakthrough” in fusion power research

There’s a lot to take away so Boundary Put together this fusion power guide with the help of some experts. We have summarized below scientists’ dreams of fusion and the harsh realities facing technology Bringing the power of fusion from scientific ambition to commercial reality.

Nuclear fusion has been an elusive energy dream for most of the century. Theoretically, it sounds simple. Stars, including our sun, create their own energy through a process called fusion, where atoms fuse together at high temperatures and pressures. Typically, it contains hydrogen atoms to create a heavier atom combine to form helium. The reaction releases a ton of energy, so scientists on Earth want to replicate it in a controlled manner. (They’ve managed to do it uncontrollably before. It’s called a hydrogen bomb.)

The nuclear power plants we have today produce electricity through fission, which is kind of the opposite of fusion. Fission releases energy by splitting atoms instead of combining them.

Theoretically, once people figure out how to achieve nuclear fusion in a controlled manner, the possibilities are endless. Hydrogen is the simplest and most abundant element in the universe. For example, you can get it from sea water. And if you do, one gallon of seawater can produce as much energy as 300 gallons of gasoline, according to the Department of Energy.

There is a big mess in today’s nuclear reactors that needs to be cleaned up thanks to fission. dividing heavily atoms, fission leaves behind radioactive waste. What to do with this nuclear waste over millions of years is an environmental nightmare that the US still hasn’t figured out.

Fusion doesn’t have these problems. With fusion, you are building new atoms – usually helium, as in balloons. IT does not generate greenhouse gas emissions. What’s more, it’s a potentially unlimited source of weather-dependent energy, which is still a problem with renewable energy sources like solar and wind power.

It turns out, it’s really hard to recreate a star in the lab. You need an enormous amount of pressure and heat to trigger the fusion. The environment in the heart of the Sun naturally provides the extreme pressure needed for fusion to occur. Here On Earth, scientists don’t have this kind of pressure lying around, and they have to reach even temperatures. hotter than the sun To get the same reaction. Historically, this took more energy than scientists could actually produce through fusion in a lab.

This also requires an extraordinary amount of money and highly specialized technology. Considering all this, it’s incredible that we’ve managed to make any scientific progress. To actually commercialize it? That’s a whole bunch of other issues that we’ll talk about in a moment.

At 1:03 am on Monday, December 5, researchers at Lawrence Livermore National Laboratory performed “fusion ignition” for the first time on Earth.

“They sent a beam of lasers to a fuel pellet, and more energy was released from that fusion ignition than the energy of the lasers that entered it,” said Arati Prabhakar, Director of the White House Office of Science and Technology at a press conference. Conference announcing success on 13 December.

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Specifically, the experiment delivered 3.15 megajoules of energy compared to the 2.05 megajoules of the lasers used to trigger the fusion reaction. This means about 1.5 gains in energy. A modest, but net, energy gain was nonetheless an important first for fusion research.

Researchers used the world’s largest and highest-energy laser system called the National Ignition Facility (NIF). The NIF is the size of three football fields, capable of throwing 192 powerful laser beams at a single target. To achieve fusion ignition, the energy from these 192 laser beams compresses fuel in a diamond capsule roughly the size of a peppercorn and 100 times smoother than a mirror. The capsule holds hydrogen isotopes, some of which “fused” to produce energy. As a result, about 4 percent of this fuel was converted into energy.

“The fuel capsule is a BB point-sized shell made of diamond that needs to be as perfect as possible,” Michael Stadermann, director of the Target Manufacturing Program at Lawrence Livermore National Laboratory, said at a press conference on Dec. “As you can imagine, perfection is really hard and that’s why we haven’t gotten to that point yet—we still have tiny imperfections in our shells that are smaller than bacteria.”

Symmetry plays a huge role in ensuring firing when it comes to both the target and its detonation. Lasers need to be properly aligned, and when it comes to targeting, you need to maintain near-perfect symmetry while blasting your target with intense pressure and heat. Experts say it’s like squeezing a basketball to the size of a pea while maintaining a perfectly spherical shape. If you deviate from this pattern, you will expend too much kinetic energy and you will not ignite.

Not by a long shot. While the lab performed the “ignition”, they based their success on a limited definition of “net energy gain” that focused only on the output of the laser. While the lasers sent 2.05 megajoules of energy to their targets, doing so consumed a massive 300 megajoules of energy from the grid. Taking that into account, a lot of energy was still lost in this experiment.

To eventually have a fusion power plant, you would need to make a much, much larger gain of 1.5 net energy gains. Instead you will need a win of 50 to 100.

there is a lot of work to do. Researchers are constantly trying to create more precise targets by aiming for this perfectly symmetrical sphere. This is incredibly labor intensive. So much so that a single pellet target today could cost around $100,000, according to theoretical physicist Robert Rosner of the University of Chicago. Rosner previously served on the NIF’s Foreign Advisory Committee. Rosner says that for nuclear fusion to be commercialized, the cost per pellet would have to drop to a few cents because a fusion reactor might need a million pellets a day.

And if you want to achieve re-firing using lasers, you will need a setup that is more efficient and can work much faster. NIF is as powerful as it is based on laser technology of the 1980s. There are more advanced lasers today, but the National Ignition Facility is a giant – its construction began in 1997 and did not become operational until 2009. Today, it can fire its NIF laser every four to eight hours. According to Tammy Ma, a Lawrence Livermore National Laboratory plasma physicist, a future fusion powerhouse would need to fire up to 10 times per second.

“It’s a ignition capsule, one-shot. To realize commercial fusion energy, you have to do a lot of things; you should be able to generate many, many fusion ignition events per minute,” said Kim Budil, director of the Lawrence Livermore National Laboratory at the press conference. There are major hurdles.”

Yes, lasers are certainly not the only strategy used to trigger the fire. The other main strategy is to use magnetic fields to confine the plasma fuel using a device called a tokamak. A tokamak can be built much cheaper than NIF. Even private companies produced tokamaks, so more extensive research was conducted in this area.

A tokamak has not yet reached ignition. But the magnets it uses have the potential to sustain a fusion reaction longer. (In NIF, fusion reactions happen within a fraction of a nanosecond.) As a result, breakthroughs in both fields of research could help bring the power of fusion closer.

“We’ve reached the top of the hill,” says Gianluca Sarri, professor of physics at Queen’s University Belfast. Boundary. He says achieving ignition in fusion power research is essentially the “hardest step” and is essentially “downhill” from here, although there is still a long way to go.

However, achieving ignition is more of a scientific invention than practical applications for our energy system – at least for many years to come.

However, when it comes to nuclear defense and nonproliferation, achieving ignition can have a quicker effect.

The NIF was originally developed to conduct experiments to help the United States maintain its stockpile of nuclear weapons without having to blow up any of them. The 1996 Comprehensive Nuclear Test Ban Treaty banned all nuclear explosions on Earth, putting an end to underground test explosions. The NIF broke ground the following year. The nuclear ignition, which he finally achieved in the December 5 experiment, essentially mimics the uncontrolled fusion that occurs when a nuclear bomb explodes. It is hoped that achieving controlled ignition in a lab will allow researchers to validate computer models they have developed to replace live test bursts.

The most optimistic experts Boundary He spoke of hoping we could have the first fusion power plant in ten years. But while most experts are still excited about the future of fusion power, they think we’re probably still a few decades away.

No matter how long it takes, we can’t wait a decade or more for fusion power to clean up the pollution from our energy system. Research shows that the world must reduce its greenhouse gas emissions to net zero by 2050 to prevent global warming from reaching a point where humanity will struggle to adapt. my love. This is real-world progress much faster than fusion research has ever achieved.

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