UK-based First Light Fusion (FLF) says it made progress in solving a key engineering challenges in its ongoing work to design a pilot power plant capable of producing commercial energy from fusion. FLF is pursuing a form of inertial confinement fusion called projectile fusion, which creates the extreme temperatures and pressures required to achieve ‘fusion’ by compressing a target containing fusion fuel using a projectile travelling at a tremendous speed. FLF says this does not involve using complex, energy-intensive, expensive lasers, or magnets and represents a simpler, cheaper, more energy-efficient approach to achieving fusion with lower physics risk.

In March FLF became the first privately funded fusion company to fire a shot on the US Sandia National Laboratories’ Z Machine in New Mexico. The Z Machine is the world’s most powerful pulsed power facility.

First Light is pursuing a new form of inertial confinement fusion using its unique amplifier designs. The amplifier approach changes the “driver” requirements, unlocking new approaches including a high velocity projectile. This creates the extreme temperatures and pressures required to achieve fusion by compressing a target containing fusion fuel using a projectile travelling at a tremendous speed.

Standoff distance is the distance between where the projectile is launched and the target – where the fusion implosion happens. As part of its experimental programme, FLF has now successfully increased the standoff distance from 10 mm to 10 cm – a tenfold increase.

FLF said the challenge is to be able to launch a projectile accurately, at velocities of several kilometres per second while keeping it in a solid state when it hits the fusion fuel. This is a major challenge in First Light’s approach with its pilot power plant design requiring the projectile to be fired at very high speeds and accuracy.

First Light’s Machine 3 – a pulsed power machine that launches projectiles electromagnetically – has been used for this research for several years, with the highest standoff distance previously achieved being 10 mm. This is sufficient for testing the design of its amplifier technology. In a power plant, the standoff distance required is required several metres.

The experiment. which achieved the tenfold increase in standoff distance. used a design called the “electric gun”. The aim was to explore if an electric gun design could be launched to high velocity on a high energy pulsed power machine without melting, a key requirement for achieving standoff.

The projectile was maintained in a solid state over 10 cm through careful tailoring of the electric gun foil and projectile thicknesses to the M3 current pulse. The desired thicknesses were determined using simulations of the material strength, which allowed for the projectile design to maintain its strength over a flight distance of 10 cm. As well as meeting the main objective, the shot was also the highest energy electric gun ever tested.

In December 2022, the significant demonstration of Ignition was achieved by the National Ignition Facility in the US. As a result, more inertial fusion companies, including First Light, are now investing greater resource on solving the key engineering hurdles that need to be overcome to realise commercial fusion energy.

An inertial fusion power plant operates a continual pulsed process. With First Light’s amplifier approach, its power plant will work like an internal combustion engine whereby the amplifier target contains the fuel, and its fusion driver – a projectile fired at speed – is the spark plug. The target will be dropped into the reaction chamber, and then the projectile will be fired at the target to create fusion.

First Light’s aim is to design the lowest risk and simplest, most scalable plant design possible. By increasing the energy per shot, and reducing the frequency, First Light aims to achieve a smaller overall plant size with a much lower risk. First Light is working to tackle the remaining engineering challenges in designing a power plant, one of which is the standoff distance. The company’s advanced simulation capability allows it to trial thousands of options for this at pace.

First Light now has a team of five scientists and engineers working full time on the design and development of a pilot power plant, headed up by Jorge Fradera. The successful attempt to increase the stand-off distance was led by Mila Fitzgerald, a PhD student at the University of Oxford who has worked at First Light for over three years. “This is a milestone moment for First Light and the result of a huge amount of effort, time, and perseverance from the whole team,” Fitzgerald said. “As we scale up our approach and look to design a pilot power plant based on First Light’s projectile approach – one of the key challenges is being able to fire a projectile at high speeds and from a further distance. That is the basis of our current pilot plant design.”

Dr Nick Hawker, Founder & CEO of First Light commented: “We know the physics of inertial fusion works. Our recent success at Sandia shows that our amplifiers work. We have taken on the standoff challenge because it unlocks huge benefits elsewhere. This is a very significant derisking moment. There is further work to do. Now we have a solid projectile, we move on to studying and controlling the accuracy of launch.”


Image: First Light Fusion's Machine 3 (courtesy of First Light Fusion)