A New Approach to Fusion

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He says it look longer than expected to raise the money for the prototype project, but the company can now start the first phase of building the test reactor, including the development of 3-D simulations and the technical verification of components. General Fusion aims to complete the reactor and demonstrate net gain within five years, assuming it can raise another $37 million.

If successful, it believes it can build a grid-capable fusion reactor rated at 100 megawatts four years later for about $500 million, beating ITER by about 20 years and at a fraction of the cost.

"I usually pass up these quirky ideas that pass my way, but this one really fascinated me," says Fowler. He notes that there are immense challenges to overcome, but the culture of a private startup may be what it takes to tackle them with a sense of urgency. "In the big programs, especially the fusion ones, people have gotten beat up so much that they've become so risk averse."

General Fusion's basic approach isn't entirely new. It builds on work done during the 1980s by the U.S. Naval Research Laboratory, based on a concept called Linus. The problem was that scientists couldn't figure out a fast-enough way to compress the plasma before it lost its donut-shaped magnetic confinement, a window of opportunity measured in milliseconds. Just like smoke rings, the plasma rings maintain their shape only momentarily before dispersing.

Nuclear-research giant General Atomics later came up with the idea of rapidly compressing the plasma using a mechanical ramming process that creates acoustic waves. But the company never followed through--likely because the technology to precisely control the speed and simultaneous triggering of the compressed-air pistons simply didn't exist two decades ago.

Richardson says that high-speed digital processing is readily available today, and General Fusion's mission over the next two to four years is to prove it can do the job. Before building a fully functional reactor with 220 pistons on a metal sphere, the company will first verify that smaller rings of 24 pistons can be synchronized to strike an outer metal shell.

Glen Wurden, program manager of fusion energy sciences at Los Alamos National Laboratory and an expert on magnetized target fusion, says General Fusion has a challenging road ahead and many questions to answer definitively. Can they produce spheromaks with the right densities, temperature, and life span? Can they inject two spheromaks into opposite ends of the vortex cavity and make sure they collide and merge? Will the acoustic waves travel uniformly through the liquid metal?

"You can do a good amount of it through simulations, but not all of it," says Wurden. "This is all very complex, state-of-the-art work. The problem is you're dealing with different timescales and different effects on materials when they're exposed to shock waves."

Los Alamos and General Fusion are collaborating as part of a recently signed research agreement. But Richardson isn't planning on a smooth ride. "The project has many risks," he says, "and we expect most of it to not perform exactly as expected." However, if the company can pull off its test reactor, it hopes to attract enough attention to easily raise the $500 million for a demonstration power plant.

Says Fowler, "Miracles do happen."