BRITAIN'S FUSION PROJECTILE

N - August 13, 2025 - UK-based inertial fusion company First Light Fusion (FLF) confirmed that it had achieved fusion using its unique technology. The UK Atomic Energy Authority (UKAEA) independently validated the result.

This is the first time fusion has been achieved using the unique targets developed by First Light, and the corresponding projectile technology. First Light’s projectile fusion is a new approach to inertial fusion that is simpler, more energy efficient, and has lower physics risk. First Light achieved fusion having spent less than £45m ($60.5m), and with a rate of performance improvement faster than any other fusion scheme in history.

Instead of using complex and expensive lasers or magnets to generate or maintain the conditions for fusion, FLF compresses the fuel inside a target using a projectile travelling at tremendous speed. The key technology is the target design, which focuses the energy of the projectile, imploding the fuel to the temperatures and densities needed to make fusion happen.

In February, FLF, founded in 2011 as a spin-out from the University of Oxford, announced a policy change. The company decided to discontinue the proposed development of its demonstrator, Machine 4, to focus on advancing and commercialising its patented amplifier technology. In March, the company announced the next phase of its commercial and technical strategy that will see it enable a faster, cheaper and scalable route to commercial inertial fusion energy with frontier industry partners.

To deliver its fusion result, First Light used its large two-stage hyper-velocity gas gun to launch a projectile at a target, containing the fusion fuel. The projectile reached a speed of 6.5 km per second before impact. First Light’s highly sophisticated target focuses this impact, with the fuel accelerated to over 70 km per second as it implodes, making it the fastest moving object on earth at that point.

First Light’s power plant design involves the target being dropped into the reaction chamber and the projectile launched downwards through the same entrance, so it catches up with and impacts the target at the right moment. The impact is focused and amplified by First Light’s advanced target technology, and a pulse of fusion energy is released. That energy is absorbed by the lithium flowing inside the chamber, heating it up. The flowing liquid protects the chamber from the huge energy release, sidestepping some of the most difficult engineering issues in other approaches to fusion. Finally, a heat exchanger transfers the heat of the lithium to water, generating steam that turns a turbine and produces electricity.

The equipment is relatively simple, built in large part from readily available components. FLF believes this approach accelerates the journey towards commercial fusion power as there is a large amount of existing engineering that can be reused to realise its proposed plant design.

Using this simpler approach, FLF says projectile fusion offers a pathway to a very competitive Levelised Cost Of Energy of under $50/MWh, directly competing on cost with renewables. This would make it the most cost competitive source of baseload power.

This approach, centred around the sophistication of the target design, will also enable FLF to pursue a high value-added consumables business model (mass manufacture of the targets themselves), where it will partner with power plant operators and become the fuel provider in the form of the targets. By focusing not just on the science, but also on its future business model, FLF believes this shows, not just the environmental but also the commercial benefits of projectile fusion power.

UKAEA was invited to analyse and validate First Light’s fusion results before they were officially made public. The process included: independent modelling of the detector configuration and response; review of all calibration data for both types of neutron detector used; review of the processing and statistical analysis of the data; full physical access to all detection equipment for hands-on inspection; and the witnessing of a fusion shot. This took place over three months and UKAEA said it is able to confirm there is evidence that First Light has produced neutrons that are consistent with those produced from the fusion of deuterium fuel.

Plans for a “gain” experiment (more energy out than in) are advancing. FLF also expects to partner with existing power producers to develop a pilot plant. It is planning a pilot plant producing around150 MW of electricity and costing less than $1bn in the 2030s. First Light is working with UBS Investment Bank to explore strategic options for the next phase.

Dr Nick Hawker, FLF co-founder and CEO said: “Our approach to fusion is all about simplicity. Being simple, we believe projectile fusion is the fastest path to commercially viable power generation from fusion. We aim for simplicity in the power plant engineering, but we also want to make the fusion process itself as simple as possible. The key technology is our target designs. As objects, these are very complex, but the physics is simpler than other fusion approaches; it can be understood and simulated accurately.”

He added: “With this result we have proven our new method for inertial fusion works and, more importantly, we have proven our design process. The design used to achieve this result is already months out of date. As soon as we reach the maximum with one idea, we invent the next, and that incredible journey of discovery is what is so exciting.”

Professor Yiannis Ventikos FREng, Kennedy Professor, Head of Department for UCL Mechanical Engineering, and co-founder of First Light said: “While achieving fusion in the lab is a tremendous success in its own right, the context is equally important. True to First Light’s rigorous scientific approach, this result is supported by strong and continuously evolving computer modelling. This capability sheds light, in exquisite detail, into the processes that generate these neutrons. Such tools are in daily use by First Light’s scientists, helping design unique targets, launchers and amplifiers, navigating the challenging path towards gain and a first-of-a-kind reactor. This pursuit of practical and affordable fusion will give us the clean and abundant baseload power that we so desperately need in our effort to address – and hopefully reverse – global warming.”

Bart Markus, Chairman of First Light Fusion, said: “Our unique target technology enables a business model based on consumables, which differentiates us from all other fusion technologies…. Our focus on the business model is equally important: fusion must show it is more than an expensive science experiment, but that it can be a commercial solution to the challenge of producing baseload clean energy”.

Business & Energy Secretary, Kwasi Kwarteng, said: “First Light Fusion’s British-born technology could potentially revolutionise power production in the coming decades. That is why this government is investing in UK science and innovation, ensuring that we remain at the forefront of the global scientific endeavour to make safe, clean, limitless fusion energy a reality.”

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