Big Friendly Gun
With the “Big Bertha” to nuclear fusion – every shot of the BFG melts hydrogen
Why be gentle when you can be brutal? The British company First Light Fusion has built a 20 meter long cannon that fires fusion energy.
The basic principles of a fusion reactor were discovered by Soviet scientists as early as the early 1950s. And all major state research institutes follow her idea. In a donut-shaped ring – the tokamak – plasma is heated, accelerated and compressed by magnetic force – this should go on until conditions like the sun prevail in the ring.
As lean as the idea is, countless scientists are struggling to put a tokamak reactor into operation. For more than 50 years in vain, only in the last few years have there been developments that give any hope of generating energy in this way. So far, more energy had to be put into the process than could be gained – the supposed reactor was not an electricity producer, but a consumer.
Another way to the energy of the sun
All over the world, start-ups are also working to solve this problem. They don’t even try to build a huge and infinitely expensive tokamak reactor. They are looking for another way to fuse the hydrogen atoms. First Light Fusion from Oxford goes one way. You could casually say that their focus is not on the sun but on the hydrogen bomb – and this technology was developed and tested in practice as early as the 1950s.
Instead of a continuous process, “explosions” are created. And it works like this: As announced, the company has built its demonstrator, a cannon over 20 meters long. Its name is: Big Friendly Gun (BFG). It is a fully functional prototype. BGF doesn’t just look like a cannon, it actually is one. A propellant charge weighing around 3 kilograms is ignited in it, which drives a piston, the piston races through the tube and compresses hydrogen, the gas is extremely compressed at the outlet, pushes through a metal seal into a vacuum chamber – at the finish it comes to a head fusion of atoms.
The whole facility was built for just £1.1million. A joke compared to the cost of state fusion reactors. CEO Nick Hawker told Newsweek: “I would call tokamaks the leading approach in magnetic fusion. But in all the years that tokamak technology has been studied, the main question has been why the plasma loses energy. You have found that the energy in the plasma tends to escape through the intense magnetic field lines involved in the reaction, causing the reaction to fizzle to achieve, i.e. to generate more energy than is required for the operation of the machine.”
“Magnetic fusion is like a furnace,” says Hawker. “It’s a perpetual hot process because the particles are going around the donut. Our inertial fusion, on the other hand, is more like an internal combustion engine. It’s a pulsed process where you have a repetition rate, and the energy per event multiplied by the frequency gives the power .”
Ready for use in the 2030s
The cannon BFG is just one step towards that vision. The company is currently working on its next machine, the M3. Instead of an exploding propellant, an electromagnetic rail gun is to be used. Hawker expects the First Light Fusion reactor to be producing usable electricity as early as the 2030s. In the planned First Light reactor, the ignition is to be repeated every 90 seconds. “Each impact releases about the same amount of energy as a barrel of oil,” Hawker said. “The energy density is literally a million times that of a chemical reaction. It also has a higher energy density than nuclear fission.”