The breakthrough came in an incredibly short period of time, taking less than a ray of light to move a centimeter. In that tiny moment, nuclear fusion as an energy source went from a distant dream to reality. The world is now grappling with the ramifications of the historic milestone.
For Arthur Pak and the countless other scientists who have spent decades getting to this point, the work is just beginning. Pak and his colleagues at Lawrence Livermore National Laboratory now face a daunting task: do it again, but better – and bigger.
That means perfecting the use of the world’s largest laser, housed in the lab’s National Ignition Facility that sci-fi fans will know from the movie Star Trek: Into Darkness, when it was used as a set for the warp core of the spaceship was used company.
Just after 1 a.m. on December 5, the laser fired 192 beams in three carefully modulated pulses at a cylinder containing a tiny hydrogen-filled diamond capsule to trigger the first fusion reaction, which produced more energy than was needed to create it . It has paved the way to a new, carbon-free energy source that scientists hope will one day use the same energy source that lights the stars.
Pak, who joined Lawrence Livermore’s lab outside of San Francisco in 2010, woke up at 3 a.m. that day and couldn’t resist reviewing the initial results from his home in San Jose. He had tried to stay awake for the shot himself, and finally gave up as the experiment’s careful preparations dragged on late into the night. “If you stayed awake for every shot for 10 years, you would go insane,” he said.
In recent months it was clear his team was close, and in the predawn darkness he searched for a key number that could show if they were successful – a number of neutrons the blast produced.
“When I saw that number, I was blown away,” he said.
“You can work your whole career and never see that moment. You do it because you believe in the goal and like the challenge,” said Pak, the experiment’s lead diagnostics. “When people come together and work together, we can do amazing things.”
The team at Lawrence Livermore — a federally funded research lab — is expected to conduct its next test in February, and several more experiments will follow in the months thereafter. The aim will be to further increase the amount of energy generated during the reaction. That means more tinkering: use more laser energy. Fine tuning of the laser beam. Generate more X-rays inside the target – a key step in the process – with the same amount of energy. Perhaps upgrade the facility itself, a decision that would require Department of Energy approval and a huge amount of funding.
All of this will take years, if not decades, starting with the Lawrence Livermore lab’s bite-sized experiments, which last only nanoseconds.
“We have to ask ourselves: Can we make it easier? Can we make this process easier and more repeatable? Can we start doing it more than once a day?” said Kim Budil, director of the Lawrence Livermore Laboratory. “Each of these is an incredible scientific and technical challenge for us.”
Most experts predict that the world is at least 20 to 30 years away from fusion technology becoming viable on a scale large and affordable enough to generate commercial power. This timeline puts nuclear fusion outside the scope of achieving the world’s net-zero emissions goals by 2050. In this sense, nuclear fusion could be the zero-carbon energy source of the future, but not the current global energy transition that faces constant hurdles.
Fusion has captured the scientific imagination for decades. It is already being used to give modern nuclear weapons their devastating power, but the dream is to tame it for civilian power needs. If it can be scaled up, it would result in power plants that provide copious amounts of electricity day and night without emitting greenhouse gases. And unlike today’s nuclear power, which is triggered by a process called nuclear fission, it would not produce long-lived radioactive waste. Whole generations of scientists have worked on it. President Joe Biden’s chief scientific adviser, Arati Prabhakar, spent a summer in 1978 as a 19-year-old college student in bell bottoms working on the lab’s laser fusion program.
“This is such a great example of what persistence can achieve,” she said at a news conference last week. “That’s how you do really big, hard things.”
atoms fuse
The successful laser shot produced fusion reactions with an energy of 3.15 megajoules, exceeding the 2.05 megajoules emitted by the laser. It was a big bump, the first time more energy came out of the laser than came in. But the equation needs to tilt much more in the direction of how much comes out to become commercially viable.
While today’s nuclear power plants use fission, splitting atoms apart, fusion fuses atoms together. Fusion researchers have followed two main leads. Using a process called inertial confinement, Lawrence Livermore blasts targets with laser beams, imploding a small amount of hydrogen until it fuses into helium. A commercial plant using this approach would have to repeat the process over and over extremely quickly to generate enough energy for the grid.
Numerous companies are developing inertial confinement systems, although there are significant differences. Some look for different materials for the target, while others use particle accelerators instead of lasers and start the fusion reaction by banging atoms together.
The main competing idea is called magnetic confinement, with systems that create a plasma cloud that can be superheated to hundreds of millions of degrees and trigger a fusion reaction. Powerful magnets control the plasma and sustain the reaction. This approach has not yet achieved a net energy gain, and the approach faces challenges including developing better magnets and creating materials that can withstand super-hot temperatures and use for the container to contain the plasma.
According to the Fusion Industry Association trade group, about $5 billion in funding has flowed into fusion companies to date, the vast majority of which are aimed at magnetic confinement technologies.
Inertial confinement might be better suited to proving fusion can work, said Adam Stein, director of nuclear energy innovation at The Breakthrough Institute, an Oakland, Calif.-based research group. But in the longer term, when it comes to commercialization, “magnetic plasma confinement is more likely to be successful,” he said.
“Be an optimist”
Years were spent in Lawrence Livermore’s lab refining every part of the process.
Much of the success was based on precision. The fuel capsules all contain tiny imperfections that can significantly affect the course of the reaction. The frozen hydrogen inside can be a mixture of the isotopes deuterium and tritium. The team would often produce the hydrogen ice, remelting it and retrying multiple times before taking a shot, hoping to get the best possible aim and increase the odds of success.
Anyone working on Fusion “has to be an optimist,” said Denise Hinkel, a physicist who focuses on improving the predictive ability of the program’s computer simulations and who has worked at Lawerence Livermore for 30 years. “Otherwise you wouldn’t stay on the field.”
The giant laser will be able to deliver about 8% more energy this summer than during this month’s firing, according to Jean-Michel Di Nicola, chief engineer of the National Ignition Facility’s laser. Michael Stadermann, program manager for target fabrication, said the lab is also developing a computer program that can inspect the fuel capsule shells for flaws much faster than humans. They are also working with the capsule manufacturer to improve the manufacturing process.
It is possible that Lawrence Livermore’s breakthrough will remain just a moment in the history of science and not mark the beginning of a new fusion industry powering the globe. Bridging the gap from experimentation to commercialization could take decades, if it happens at all. And magnetic confinement could eventually be the fusion method that catches on and provides the world with plenty of clean energy. Pak, a soft-spoken man with a shock of brown hair and a quick wit, said the result did not disappoint.
“They can learn from us — we can learn from them,” said Pak, 40. “When I’m an old man, I’ll be really happy with my contributions.”
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