If humanity survives for thousands more years, our primary energy source could very likely be nuclear fusion. It’s clean, the fuel is inexhaustible and cheap, and there’s no risk of a meltdown. It’s the power source of the stars — the whole cosmos, in fact. And we’re tantalizingly close to making it work. The downside is that the particular reactor now making the important breakthroughs in fusion is linked inextricably to nuclear weapons research.
That’s not necessarily a deal breaker, but it presents risks that the public should know about and weigh in on.
On July 30, scientists at Lawrence Livermore National Laboratory repeated last December’s long-sought achievement of creating more energy in a peppercorn-sized capsule then they’d beamed in with lasers. The machine called the National Ignition Facility, or NIF is now the world leader in the fusion quest.
It’s not anywhere near ready for commercial use — the break-even point, called ignition, describes what happened in the capsule, but the scientists still put a lot more energy into firing up the lasers than they got out in fusion power. We’re still probably 20 years away — at least — from commercial fusion.
While current nuclear power plants work by nuclear fission, the splitting of the nuclei of larger elements, fusion is the merging of two nuclei of light elements. The sun and stars are powered by hydrogen nuclei fusing into helium. Oxygen and carbon and other elements essential to life were forged from fusion in distant stars that exploded. Fusion also lights up the glowing matter around black holes, as recently captured in NASA images.
In both fission and fusion, a small amount of mass is converted into a lot of energy. In laboratory fusion experiments, scientists usually use deuterium and tritium (hydrogen with one and two neutrons). While tritium is rare, it could be made in a reactor once it gets going. Deuterium is inexhaustible.
“There’s enough deuterium in seawater to power the planet for 60 billion years,” which is far longer than our planet will exist, said Steven Cowley, a fusion physicist and director of the Princeton Plasma Physics Laboratory.
If there’s a downside, it’s not with the goal, but with the road the US took to achieve its recent milestones. The National Ignition Facility wasn’t built as a way to identify a source of clean energy but to advance US weapons of mass destruction.
“The reason NIF is funded is for nuclear weapons research. It is not funded for fusion energy or for basic science. Those are just spinoff benefits,” said Stewart Prager, a fusion physicist and professor at Princeton University who works with the program on science and global security.
The machine can do something equivalent to testing upgraded or new nuclear weapons without violating test ban treaties. The breakthroughs in December and this summer in achieving ignition will finally allow the machine to fulfill its weapons-testing mission.
How that affects the delicate system of mutual deterrence with the other nuclear powers remains unknown, but Prager and other scientists who study nuclear security say it could make the world more dangerous. While US schoolchildren no longer do nuclear drills, there’s still a risk that nuclear weapons will destroy our civilization before climate change does.
While the initial nuclear weapons created in the Manhattan Project depended on fission, most of the US nuclear arsenal is made up of so-called thermonuclear bombs, which get their power from fusion. These weapons can pack hundreds of times the destructive power of the bombs dropped on Hiroshima and Nagasaki. The current US stockpile could destroy humanity many times over.
The NIF can help ensure that none of our weapons blow up in their silos. But it seems insane to suggest that the US needs to improve them. “Is there any doubt that nuclear weapons work? Is there any doubt that they’re completely annihilating?” Prager said. “It makes no sense to think we need to further improve nuclear weapons.”
Ideally, research into fusion power wouldn’t have to be mixed up with nuclear weapons. The breakthroughs at NIF should attract more talent and encourage investment in purely commercial ventures. There are already at least 30 startups working on nuclear fusion schemes using government grants and billions of dollars in private investment money.
Most of those projects take a different approach from NIF, holding the fuel for a sustained period of time using a powerful magnetic field. Several projects have demonstrated they can hold the fuel at a sustained temperature of 250 million degrees C, said Cowley. A UK experiment called JET has been breaking records, and a controversial international megaproject in France, called ITER, while much delayed, could be up and running later this decade.
Another hurdle is getting enough tritium to kick-start the process. To get around this, some scientists are experimenting with other fuel combinations. A California-based company called TAE Technologies is using hydrogen and boron, while, Helion, based in Washington, will fuse deuterium and helium-3, a rare helium isotope.
These diverse efforts are moving closer to fusion thanks to breakthroughs in nanomanufacturing, artificial intelligence and high-temperature superconductors, which are needed to make the coils that produce the extreme magnetic fields.
While fusion won’t solve our immediate climate problem — we can’t wait 20 years or more to adopt cleaner fuel sources — it could be part of the long-term solution. The nascent fusion industry deserves funding and support for its own sake, not as a side benefit of the nuclear weapons business.
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