The Energy Squeeze is On: World energy consumption is expected to increase by over 50% by 2030 yet world energy reserves for non-renewable sources are running out. Where is the energy going to come from?
Greenhouse gases (GHG), such as CO2, are altering the world's climate. Atmospheric CO2 has climbed by 25% since the 1950s and is approaching levels where scientists predict unavoidable consequences.
The Case For General Fusion
How it Works
General Fusion has developed its technology from the beginning knowing that success requires more than solving science challenges. For General Fusion, success means delivering fusion energy with an approach that has a clear and practical path to commercially-viable and competitive power generation.
Dr. Peter Turchi, Former Chief, Plasma Technology Branch, Naval Research Laboratory
The thick liquid metal wall surrounding the fusion reaction in General Fusion’s system is a major practical advantage. The energy from the fusion reaction is absorbed by the liquid metal, shielding the steel sphere and preventing damage. As it is absorbed, the energy heats the liquid metal and the hot liquid metal can be used to create steam, a convenient way to extract the fusion energy. The lithium in this same liquid metal is also easily bred into the tritium fuel required for ongoing operation.
Key Advantage: Compressed Gas
All fusion systems must first heat their fuel to extreme temperatures to initiate fusion reactions. This requires energy, and the cost of most fusion systems is high because of expensive energy drivers. Inertial confinement fusion, for example, uses massive capacitor banks and lasers to drive their fusion reaction.
General Fusion, on the other hand, uses steam, a compressed gas that is a proven and inexpensive way to store and release a lot of energy. Using computer-controlled, steam-driven pistons allows General Fusion to power a fusion reaction for less than 1% the cost of other fusion drivers.
It is often proposed that pulsed rather than steady-state approaches may be more practical for fusion. Most pulsed systems, such as inertial confinement, use targets made of lead, aluminum, and even gold, which are destroyed on each pulse. The amount of electricity produced from a single pulse would be worth only a few dollars, so these targets must be very inexpensive for these pulsed systems to be practical. In contrast, the target in General Fusion’s system is a spheromak plasma composed entirely of fusion fuel – there are no consumables.
Where We Are
Above and below the central sphere in General Fusion’s system are plasma injectors. These cone-shaped devices form a “spheromak”, a doughnut-shaped plasma, wrapped in magnetic field. The spheromak is then accelerated down the cone, compressing and heating the plasma.
Full scale plasma injectors – the largest in the world – have been constructed to demonstrate formation of the required spheromak plasma.
Key Subsystem: Acoustic Drivers
General Fusion’s novel system to deliver energy to heat the hydrogen fuel to fusion conditions are the acoustic drivers, or pistons. Powered by steam and controlled by advanced electronics, they drive a heavy piston (the “hammer”) against a second piston (the “anvil”) that is inserted in the side of the sphere. On impact, the energy from the hammer is transferred quickly through the anvil and into the molten lead-lithium.
Full scale acoustic drivers have been constructed to demonstrate that they can achieve the required impact velocity (energy) and impact timing control.
At the core of General Fusion’s system, molten lead-lithium is pumped in a 3 metre diameter sphere to form a smooth cylindrical vortex. This vortex is used to confine and compress the plasma.
A 1 metre diameter mini-sphere with 14 full-scale acoustic drivers has been constructed to test liquid metal vortex formation and compression.
Where We're Going
Magnetized Target Fusion
LINUS – The Original MTF Power Plant
LINUS was the first full power plant concept based on Magnetized Target Fusion. Developed in the 1970s at the U.S. Naval Research Laboratory near Washington, DC, LINUS included many of the features General Fusion has leveraged in its own approach, such as thick liquid metal walls and a compressed gas driver. Due to the plasma and electronics technology available at the time, the LINUS design proved impossible to build.
Commercialization Challenges: Magnetic Confinement Fusion systems will be very large and use expensive, exotic technologies for plasma confinement. New materials need to be invented to withstand the harsh plasma environment, and heat extraction and tritium breeding will be very difficult.
Magnetic Confinement Fusion
T-1: The Original Tokamak
The most successful Magnetic Confinement Fusion approach, called a “tokamak”, was invented by Soviet physicists in the 1950s at the Kurchatov Institute in Moscow. The T-1 tokamak, pictured here, was the first built. Later versions improved on the design and in 1968, the T-3 tokamak achieved an important breakthrough in confinement quality which spurred major tokamak construction and research programs around the world.
Joint European Torus (JET)
The Joint European Torus (or “JET”) is located at the Culham Center for Fusion Technology in the UK. In 1997, JET achieved a fusion power record, producing 16 MW or 70% of the energy required to heat the plasma. This marked a 100,000 fold improvement in fusion power from the results achieved by the Soviet T-3 tokamak in 1968 and illlustrated the progress made by fusion researchers in a few decades.
The world’s largest tokamak will be ITER, currently under construction by a consortium of USA, Russia, Japan, China, India, South Korea, and the European Union.
The ITER project was started in 1988. Construction is now underway in France with operation expected to begin in 2023 and net energy around 2030. A prototype power plant, called DEMO, is planned following the ITER project.
Commercialization Challenges: Inertial Confinement Fusion systems will need major advances in laser efficiency, a 1,000-fold reduction in target cost, optics that don't degrade, and new materials to withstand the harsh environment facing the plasma.
Inertial Confinement Fusion
National Ignition Facility (NIF)
The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in the USA is the world’s largest Inertial Confinement Fusion system, and the world’s most powerful laser. NIF is designed to primarily to support weapons-related research, but is also attempting to reach ignition using ICF for the first time.