November 9, 2019


Nuclear fusion is 'a question of when, not if' (Matt McGrath, 11/06/19, BBC)

[P]erhaps the major excitement comes from private companies. They are usually smaller, nimbler, and they develop by making mistakes and learning from them quickly.

There are now dozens of them around the world, raising funds and pushing forward often with different approaches to fusion than that seen in Iter and in the UK.

Here's a brief sample of some different approaches to fusion.

First Light: This company originated in the University of Oxford and was founded specifically to address the urgent need to decarbonise the global energy system. Their idea involves firing a projectile at a target that contains hydrogen atoms. The shockwave from the impact of the projectile creates a shockwave that crushes the fuel and briefly this reaction will produce plasma that is hotter than the sun and denser than lead.

Commonwealth Fusion Systems: A private company created by former Massachusetts Institute of Technology (MIT) staff, CFS has raised significant funding of over $100m. It is focusing on developing a Tokamak system but its key innovation is in superconducting magnets. They hope to build powerful enough magnets so they can build smaller and cheaper Tokomaks to contain the plasmas required to generate fusion.

TAE Technologies: With backing from Google and other high tech investors, this California-based company is using a different mix of fuel to develop smaller, cheaper reactors. They want to use hydrogen and boron as both elements are readily available and non-radioactive. Their prototype is a cylindrical colliding beam fusion reactor (CBFR) that heats hydrogen gas to form two rings of plasma. These are merged and held together with beams of neutral particles to make it hotter and last longer.

US Navy: Worried about how to power their ships in the future, the US Navy has filed a patent for a "plasma compression fusion device". The patent says that it would use magnetic fields to create "accelerated vibration and/or accelerated spin". The idea would be to make fusion power reactors small enough to be portable. There's a lot of scepticism that this approach will work.

One of the main challengers with ambitions to make fusion work is a company based in British Columbia, Canada called General Fusion. Their approach, which has gathered a lot of attention and backing from the likes of Amazon's Jeff Bezos, combines cutting edge physics with off the shelf technology.

They call their system "magnetised target fusion".

This approach sees a hot gas plasma injected into a ball of liquid metal inside a steel sphere. It is then compressed by pistons, much like in a diesel engine.

"The pistons all fire simultaneously and collapse the cavity with the fuel inside," said Michael Delage, the company's chief technology officer.

"So at the peak of that compression when the fuel bursts into fusion reaction, it is surrounded on all sides by liquid metal so the energy goes into the metal and you take this hot liquid metal and boil water, make steam and make electricity."

General Fusion say they hope to have a working model within five years.

Posted by at November 9, 2019 12:00 AM