The implosion of the bubble created by the pistol shrimp is so intense that it produces a tiny plasma that emits its own light. Long before humans mastered fire, there was an entire family of shrimp that could create plasmas of five thousand degrees under the ocean.
It’s a little humbling.
Nick Hawker didn’t have much interest in doing a PhD until the person who would become his supervisor offered him a position trying to re-create the pistol shrimp’s plasma in a computer simulation. Nick’s work in understanding this effect has led him from crustaceans to cooking up a star at his company, First Light Fusion. Nick explains that they wondered, “If we keep increasing the intensity of the shock wave, does the temperature keep going up or does it go unstable and stop working as most fusion things do?” The answer, the First Light Fusion team believes, is that these shock waves can reach fusion conditions.
Shock waves, like the sonic booms made by aircraft flying faster than the speed of sound, are special. Extreme ones can, in nanoseconds, increase the density and temperature of a material to the point that its atoms dissociate into plasma. They’re often a key part of how inertial confinement fusion works, including at NIF. A pistol shrimp can create a bubble-collapse shock wave that Nick describes as “quite modest” at two kilometers (a little more than a mile) per second. That’s the speed of the fastest ever crewed rocket-plane. First Light matched that implosion speed with their first star machine, a gas gun that used a small chemical explosion to propel a solid projectile. They’re now on their third machine.
As I walk around First Light Fusion’s laboratory, it’s hard not to be impressed by the clean, tight ship they run. When I enter the building, I find a reception area that is all start-up, complete with plush chairs and bright colors. Whiteboards, wiped clean for my visit, adorn the walls. There’s a fancy coffee machine in the kitchen. In a nice touch for a lab that must be obsessed with diagnosing temperatures, every water jug has a little thermometer attached to it. And the areas where the experiments are done are absolutely spotless.
How First Light Fusion plans to build a star is to accelerate a small piece of material—they wouldn’t tell me what but probably a slug of metal not much bigger than a coin—into a target that contains deuterium and tritium. When the slug smashes into the target, it produces a shock wave with enough energy to create a high-temperature, high-density plasma. They calculate that they need a collapse of fifty kilometers (approximately thirty miles) per second for fusion, but—and this is their top secret innovation—the way their shock wave interacts with their target multiplies the collapse velocity many times over. Their approach is based on inertial confinement and so has similarities to laser fusion, except that they’ve replaced the laser pulse with a “pulse” of solid matter.
First Light Fusion’s latest step on the way to a full-blown star machine is an electromagnetic rail gun named Machine 3. It has been lovingly assembled as a six-limbed fourteen-mega-amp monster. It charges in fifty seconds and deposits all of its energy into the projectile in just two microseconds. Each shot uses 2.5 megajoules of energy. It is electromagnetic because chemical processes can’t go fast enough. The rail gun uses a current in one direction (along one rail, through the projectile, and back by the other) and magnetic fields (in a cylinder around each rail) to force a projectile to accelerate in the third direction.
In principle, this electromagnetic rail gun can propel objects to speeds of twenty to thirty kilometers per second, but so far, First Light can only be sure they’ve hit fifteen. A satellite reaches seven kilometers per second during reentry from Earth orbit. I know this because First Light Fusion’s head of numerical physics, directing ten people and a supercomputer with two thousand CPUs, previously modeled satellite reentries for a living. Even at this speed, the shock wave that builds up in front of the satellite is strong enough to rip apart atoms into plasma. At tens of kilometers per second, First Light is well into the plasma physics regime.
Even though I’ve visited star builders at top secret government laboratories, at a site handling nuclear materials, and at other start-ups, First Light Fusion is by far the most secretive. No mobile phones are allowed beyond the reception area, a restriction that didn’t even apply at Lawrence Livermore National Laboratory. Most visitors who see the inside of First Light Fusion’s offices are asked to sign a nondisclosure agreement. When I ask about all this secrecy, they explain that the target technology—what turns their shock wave into a fusion initiator—is a trade secret. Hawker tells me that patents aren’t much good if you’re a small fry because patent battles are always won by the bigger fish in court. But no one can copy a trade secret as long as demonstrable effort has been put into protecting it.
It’s interesting that First Light is so averse to patents. The assumption made by some fusion start-up skeptics is that the real business plan of private sector star builders is to either generate a few high-tech patents to sell off or to be bought out by another firm. Flogging patents, whether to investors or to other firms, is not a new trick; there was a significant boom in the 1690s as firms piling into the sunken treasure industry sought to establish their credentials (Daniel Defoe was among those caught out by the “patent-mongers”).3 Selling up is a common strategy for start-ups, and when it works well, both investors and employees can come out happy. But, like the pistol shrimp, First Light has no intention of being swallowed by a bigger fish.
“For us, getting bought is actually plan B or C,” Gianluca Pisanello, the chief operating officer, tells me. The business plan is to retain control over the rights to the secret fusion targets, but to let big industry build the power plants. “At the end of this process, we will have two fundamental pieces of intellectual property in our pocket: one is the target, one is the driver. We will make money by selling the targets.”
Like Nick Hawker, Gianluca Pisanello is typical of the new wave of star builders. He’s an engineer by training. His dream was to be a Formula 1 racing engineer. After studying electronic engineering, he made his dream come true, working for Toyota and other teams, and eventually becoming chief engineer for a team of sixty people. When I commented on the astounding cleanliness of the laboratory, he flushed and said that he tried to bring his Formula 1 standards to fusion. Gianluca’s job as chief engineer in the racing business was to optimize every aspect of car plus driver to gain fractions of a second. It was extreme engineering. Or so he thought, until he became a star builder.
One day Gianluca received a call from a headhunter who told him about First Light Fusion. Even though it seemed like a long shot, and he didn’t know much about fusion at the time, he couldn’t quite bring himself to say no. Eventually, he said yes.
“I realized I didn’t care if we succeeded,” he told me. “What I wanted was to be part of this journey, and if this happens, and there was an opportunity to be involved, and you didn’t take it… well!”
Every star-building start-up claims it has what it takes, that it’s different from the competition, special. First Light Fusion’s story is about trying to use the most tried and tested technologies wherever possible. This way, the innovations, and the risk, will be concentrated in the targets. By buying almost everything else off the shelf, Nick Hawker and his colleagues reduce the overall risk of what they’re doing. I can’t help but admire the clarity and pragmatism of the vision.
While Gianluca Pisanello thinks the big laboratory competitors, JET and NIF, could get energy gain, he and First Light believe their approach sidesteps the big fusion engineering challenges that will make it difficult to build a first-generation power plant.
First Light Fusion’s vision for a power-producing star machine involves one target at a time being dropped into a chamber, followed by a much faster projectile that catches up to it. When the two collide, fusion reactions will be triggered. Surrounding the fusing plasma will be a cylindrical wall of liquid lithium—imagine standing inside a circular waterfall, but instead of water, it’s metal. The liquid lithium will abso
rb the neutrons, making precious tritium that can be used as fuel. Heat energy carried by the neutrons that gets into the lithium will be exchanged into another medium like water. Ultimately, the water will be turned to steam to drive a turbine. The whole process will repeat somewhere between every five or every forty seconds.
Before coronavirus struck, First Light Fusion had a plan to perform a net-energy-gain experiment by 2024, and they say they’re about to reach the temperatures where fusion reactions first become detectable. But what both Gianluca and Nick are keen to stress is that they’re not in the net-energy-gain business: they’re in the power business.4
“It’s the world’s largest problem,” Nick tells me, referring to achieving fusion. “Most scientists are working on the physics, which is a bit of the problem but not the whole problem. Demonstrating gain is not valuable. Heat and light are valuable.”
One challenge that I level at him is that they’re making their most important innovations secret, but science moves forward more quickly when it’s done out in the open, where ideas can be critiqued and improved upon.
“Sure,” he says, “but does technology move forward more quickly?”
Engineers in Charge
Thanks to decades of publicly funded research, fusion is increasingly a technological challenge rather than a scientific one (though big scientific challenges remain). To take it to its next phase, new types of talent will be required—those who can convert scientific ideas into working technologies. Enter the engineers.
Engineers like Nick Hawker and Jonathan Carling, CEO of Tokamak Energy. The latter told me that “things like the steam engine and internal combustion engine were invented long before anyone understood how they worked. Once it kind of works, engineers will take over.” And so they are.
Just twenty miles south of First Light Fusion’s office, past Oxford’s dreaming spires, is the industrial park that houses Tokamak Energy, a fusion start-up that uses a radical tokamak design. Until very recently, Tokamak Energy’s building sat in the shadow of the great cooling towers of Didcot Power Station. For years Didcot burned oil, coal, and gas, and pretty much dominated the landscape. That is, until the towers were brought down by controlled demolition. How appropriate that this part of Oxfordshire, which is also home to JET, should see this emblem of fossil fuels fall to the ground and so many innovative fusion schemes appear.
Tokamak Energy has raised more than £117 million (about $158 million) in private investment and is looking for as much as £700 million ($936 million) for a future phase. Its star builders are nothing if not ambitious. The former CEO, now executive vice chairman, Dr. David Kingham, brought Jonathan Carling in because of the need to transition from fusion-in-principle to fusion-in-practice. David is a theoretical physicist by background, but for most of his life he has been involved in the UK’s high-tech start-up scene, previously running business accelerators that have helped launch several thousand firms.
“Fusion was always seen as too hard,” he tells me in Tokamak Energy’s meeting room, “the preserve of big government labs. That was very much a dominant view of the world until just a couple of years ago.” He’s excited about what the private sector can do for fusion. He sees the relationship between private fusion ventures and the big laboratories—like Culham—as being analogous to the relationship between SpaceX and NASA. He’s not alone—everyone I speak to in fusion start-ups keeps coming back to that analogy with space.
Tokamak Energy has taken the usual tokamak plasma shape and squished it so that it looks less like a doughnut and more like a cored apple. The resulting machine is called a spherical tokamak. The rationale behind this is really simple: magnetic fields dissipate over distance, so when the plasma is brought in closer to the core (which generates the toroidal magnetic field), less magnetic field is needed for the same amount of confinement. It also creates a more compact machine, which—given the increasing sizes of each generation of tokamaks and their high costs—would make magnetic fusion power more economical. David enthusiastically explains that there’s a lot of academic work showing that spherical tokamaks will be able to deliver fusion more quickly, with smaller, cheaper machines.5
But that’s not the only innovation that Tokamak Energy is introducing. It also plans to substantially increase the strength of the magnetic fields using high-temperature superconducting magnets. “High-temperature” here is a fairly silly term—the highest temperature these magnets operate at is twenty degrees above absolute zero. The old “low-temperature” ones only worked at two degrees Kelvin, so it’s all relative.
Magnetic resonance imaging, or MRI, machines in hospitals use superconducting technology and need to stay below around ten degrees Kelvin. They’re about the highest magnetic fields that you might experience in everyday life, capable of generating between one and three Teslas of magnetic field strength. This is similar to what Tokamak Energy is aiming for in its machine. Due to the superconductors and the plasma being so close, Tokamak Energy’s spherical devices will have one of the wildest temperature gradients in the solar system. The tokamak plasma has to be at least 100 million degrees while, a meter away, there is a superconducting magnet at 20 degrees above absolute zero.
Magnetic fields provide most of the confinement in tokamaks: the stronger the better. The fusion energy ramps up aggressively, so that an increase in the magnetic field by a factor of two means producing sixteen times as much energy per second. But it takes a lot of energy to push current—or a stream of electrons—through the tokamak’s core, usually a cooled copper wire, to create the toroidal field. When superconducting materials are used, the electrons encounter almost no resistance.6
There’s just one problem.
“Low-temperature superconductors are on a hair trigger and can be easily quenched by any amount of energy,” David Kingham tells me. Quenching is a sudden and explosive increase in electrical resistance of the conductor as it ceases to be super. A huge bang issues forth as electromagnetic energy is rapidly converted to heat, which boils off the coolant. Modern MRI machines are carefully designed to safely quench at the touch of a button, but this is no good for a power plant that needs to remain on as much as possible. Severe quenching could twist metal and permanently damage a reactor chamber.
The researchers at Tokamak Energy aren’t alone in thinking that the future will be an advanced type of tokamak. Commonwealth Fusion Systems, born out of a well-respected fusion science program at MIT, will also use superconducting technology in a new tokamak design. They believe their advanced setup will allow them to get to a fifth of the fusion power of the biggest tokamak ever designed while only having one-sixty-fifth of its volume. Commonwealth’s scientists have recently published research in academic journals that suggests their tokamak could comfortably deliver twice as much power out as is put in.7 Clearly, some investors agree because Commonwealth has received $200 million in funding. In 2018, the company’s CEO said, “We think we have the science, speed, and scale to put carbon-free fusion power on the grid in 15 years.”8
Tokamak Energy is aiming to demonstrate in principle that its machine can reach the point of a net gain in energy by 2022. This is not, strictly speaking, “more energy out than in” from fusion reactions, because they don’t want to have to work with tritium. Instead, they’re going to put the much more plentiful, and easier to handle, deuterium into their reactor and show that they can get to the conditions that Lawson’s equation says are needed to generate more energy than put in. Jonathan Carling, like Nick Hawker, explains that gain is not the point though:“The main thing we’re trying to prove is that our modeling is correct. Whether it’s just shy or just over [net energy gain] is not the important thing for us, it’s whether it’s on the curve we predict.”
The hope is that demonstrating that their modeling is correct will be enough to convince investors to fund a machine that can—in theory—produce way more than 100 percent of the energy put in using deuterium and tritium. Other fusion start-ups have similar plan
s.
Like First Light Fusion, Tokamak Energy is much more interested in power production than energy breakeven. “Achieving a Q of one is a scientific goal,” Jonathan Carling continues, “but it’s nowhere near enough to produce commercial energy, which requires a Q [in the region] of tens.” As mentioned previously, Q is the ratio of fusion power out to heating power in. His strong view is that unless other star builders have a credible plan to get to factors of twenty or thirty more power out than they put in, then they’re in the science game and not the fusion energy game. And he puts JET, the conventional tokamak at Culham, firmly in the science category.
Promises
The promise of gain (or gain conditions) by 2022 and the mid-2020s by Tokamak Energy and First Light Fusion, respectively, may seem overly optimistic to star builders in government laboratories. But these punishing timescales aren’t unusual among the new wave of private sector star builders, such as General Fusion, LPP Fusion, Lockheed Martin, TAE Technologies, HyperJet Fusion Corporation, MIFTI, Proton Scientific, Helion Energy, Commonwealth Fusion Systems, Renaissance Fusion, Zap Energy, HB11-Energy, Pulsar Fusion, and the list goes on. There are now more than twenty-five private sector fusion firms. Most are promising to deliver energy from nuclear fusion reactions in years rather than decades. Commonwealth Fusion Systems says it will achieve net energy gain by 2025 and a pilot power plant by 2033. The deadly Covid-19 pandemic may slow these timescales, but the intention is clear: fusion sooner rather than later.9
There’s fierce competition between the star-building start-ups. It’s hard not to imagine the race to demonstrate gain—and, even more so, to build a prototype power plant—being a winner-take-all contest. The victor will enjoy an influx of investors looking to ride the new nuclear wave. The losers may be able to bask briefly in reflected glory, but unless they can also demonstrate gain quickly, fusion dollars are likely to go to the firm that’s already made it happen.
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