General Fusion will build a ~3-metre diameter spherical tank filled with liquid metal (lead-lithium mixture). The liquid is spun to open up a vertical cylindrical cavity in the centre of the sphere (vortex). This vortex flow is established and maintained by an external pumping system; the liquid flows into the sphere through tangentially directed ports at the equator and is pumped out radially through ports near the poles of the sphere. Two spheromaks (self confined magnetized plasma rings) composed of the deuterium-tritium fuel are then injected from each end of the cavity. They merge in the centre to form a single magnetized plasma target. The outside of the sphere is covered with pneumatic rams. The rams use compressed gas to accelerate pistons to ~50 m/s. These pistons simultaneously impact a set of stationary anvil pistons at the surface of the sphere, which collectively launch a high pressure spherical compression wave into the liquid metal. As the wave travels and focuses towards the centre, it becomes stronger and evolves into a strong shock wave. When the shock arrives in the centre, it rapidly collapses the cavity with the plasma in it. At maximum compression the conditions for fusion are briefly met and a fusion burst occurs releasing its energy in fast neutrons. The neutrons are slowed down by the liquid metal causing it to heat up. A heat exchanger transfers that heat to a standard steam cycle turbo-alternator to produce electricity for the grid. Some of the steam is used to run the rams. The lithium in the liquid metal finally absorbs the neutrons and produces tritium that is extracted and used as fuel for subsequent shots. This cycle is repeated about one time per second.
Gilliland plans to have a so-called “alpha” plant in operation within the next few years, which would prove the viability of the technology. He sees it going much further than that, however.
“We’ve got literally billions of years of fuel,” he says. “Where we hope to be in a few years is that a very significant portion of the electricity the world is generating is from fusion.”
Aside from electricity, fusion produces a lot of heat, and that heat can be used for other applications. According to Gilliland, even an oil and gas firm has invested in order to develop a cheaper and cleaner way to extract and refine its products.