General Fusion

General Fusion is one of the oldest and most well-funded private fusion companies, founded in 2002 by plasma physicist Dr. Michel Laberge in Burnaby, British Columbia, Canada. The company has raised over $300 million USD from investors including Bezos Expeditions, Chrysalix Venture Capital, BDC Capital, and various sovereign wealth and strategic investors.

General Fusion's technical approach is based on Magnetized Target Fusion (MTF), specifically using acoustic/mechanical compression of a plasma target embedded in a liquid metal sphere. The concept works as follows:

1. A pulse of plasma is injected into the center of a rotating vortex of liquid metal (lead-lithium).
2. The plasma is magnetized by external field coils, creating a field-reversed configuration (FRC) or similar compact toroid.
3. An array of pistons (originally pneumatic, now electromagnetic) strikes the outer wall of the vessel, sending shock waves through the liquid metal.
4. The converging shock waves compress the liquid metal sphere, which in turn compresses the magnetized plasma to fusion-relevant temperatures and pressures.
5. The fusion reactions heat the liquid metal, which is then circulated to extract heat and generate electricity via a steam turbine.

The liquid metal serves multiple purposes: it acts as the compression medium, it captures the fusion energy as heat, and it serves as a tritium breeding blanket (the lithium in the lead-lithium alloy breeds tritium when exposed to fusion neutrons). This integrated approach simplifies several engineering challenges compared to other fusion concepts.

General Fusion has demonstrated key components of its approach, including plasma injection, vortex formation, and piston-driven compression. The company has operated a series of increasingly large prototype devices at its Burnaby facility. In 2022, General Fusion announced plans to build a demonstration plant at the UK Atomic Energy Authority (UKAEA) campus at Culham, Oxfordshire, with support from the UK government. This LM26 device aims to demonstrate the integrated compression process at relevant scale.

The company's approach has both advantages and challenges. Advantages include the use of relatively low-tech components (pistons, liquid metal) compared to laser systems or superconducting magnets, the integrated tritium breeding, and the pulsed nature which avoids steady-state engineering challenges. Challenges include the extreme mechanical stresses on the vessel, the need for precise shock wave convergence, and the management of the liquid metal vortex under repeated pulses.

General Fusion connects to the broader MTF/MIF research community, including Los Alamos National Laboratory (which originated much of the MTF concept through the MAGO/MAGIF experiments), Sandia National Laboratories (MagLIF), and the Air Force Research Laboratory (FRCHX, Shiva Star). The company also connects to the UK fusion ecosystem through its Culham demonstration plant and to the Canadian fusion ecosystem through its Burnaby headquarters and relationships with Canadian Nuclear Laboratories and the University of Saskatchewan.