Energy supply is one of the world’s biggest challenges. Fusion technology has the potential to solve this challenge by providing on-demand, safe and clean energy that will combat climate change while driving economic growth. Drawing on decades of advancements in plasma physics, materials engineering and computer simulation, General Fusion is working to develop the world’s first commercially viable fusion power plant.
What Makes the General Fusion System Different?
Developing a completely new form of energy comes with plenty of challenges and unknowns, so General Fusion utilizes milestone-driven R&D campaigns and ANSYS simulation solutions to reduce the risk in its development process. One such campaign focused on testing the liquid metal compression technology that forms the core of General Fusion’s power plant.
General Fusion’s system uses a sphere filled with liquid metal that is pumped around the inside to form a vortex. A pulse of magnetically confined plasma fuel is then injected into the vortex. Around the sphere, an array of pistons drive a pressure wave into the center of the sphere, compressing the plasma to fusion conditions. This process is then repeated, while the heat from the reaction is captured in the liquid metal, then used to produce steam and generate electricity via a steam turbine.
Leveraging ANSYS Simulation Provided Answers
The R&D campaign is investigating the liquid metal pumping systems and piston synchronization systems independently of the plasma injector experiments, which are being conducted in parallel.
While a spinning vortex of liquid metal is a novel system, simulation indicated that the spherical pressure wave needed to compress a magnetized plasma would need to be very uniform to achieve the desired results. This meant synchronizing multiple pistons, each with a mass of 100 kg, to within microseconds of each other.
A number of piston designs had been investigated in a previous testing campaign, reaching 50 meters per second and striking an anvil at the end of the bore to produce an acoustic pressure wave in the liquid metal. With timing controlled by a piezo braking system, pistons could be synchronized to within 10 microsecond accuracy, sufficient for plasma compression.
To demonstrate that the liquid metal pumping system could be combined with a spherical piston array, a compression system prototype was built at scale. In the engineering design of this system, the General Fusion team relied on ANSYS Explicit STR, obtained through the ANSYS Startup Program, for structural analysis, which enabled us to model the dynamic loading of the structure from pressure pulses generated by 14 large, high speed pistons on to a chamber containing 5 metric tons of liquid lead being pumped at a rate of 100 kg/s. Being built with applied engineering in mind, the ANSYS platform made it possible for our engineering team to rapidly iterate the design during this phase of the project.
The compression system prototype took approximately one year to build, and upon commissioning underwent a successful experimental campaign, firing all 14 pistons simultaneously and providing invaluable data on the behavior of the liquid metal, containment system and vortex. During testing, the results of simulations were validated against actual measurements using strain gauges, pressure sensors and displacement sensors, confirming the accuracy of the ANSYS simulations.
Images of Piston/anvil system in a segmented pressure vessel,
simulated in ANSYS Explicit STR.
Looking to the Future
With this phase of the development program complete, General Fusion continues to focus on optimizing its plasma technology and preparing for the design of a demonstration fusion power plant, with the goal of creating clean energy, everywhere, forever.