The pistol shrimp’s powerful punch may hold the key to fusion power

The pistol shrimp is well-known for the knock-out ‘punch’, the shockwave that it delivers to prey from its comparatively oversized claw.

Unlike biologists who marvel at the hunting prowess of the shrimp, Dr Nick Hawker was more interested in the energy released by the bubbles which form and then collapse when the oversized claw is snapped.

While studying for his DPhil at the Department of Engineering Science, he started modelling the process of the cavity collapse of the bubble and the resulting creation of light. The question for Hawker was whether this natural process produced enough energy to help unlock the potential of fusion.

"I was studying shock-driven cavity collapse, and that's what happens with the shrimp," he recalls. “Its huge claw makes a shockwave which stuns its prey, and it also produces bubbles. As the shockwave passes over the bubbles, it makes them collapse. When they collapse, you get these bright flashes of light. It’s called shrimpoluminescence.”

The modelling showed the process held enough promise for Hawker and his DPhil supervisor, Professor Yiannis Ventikos, to form First Light Fusion in 2011. Just over a decade later, the company is now the world’s leading inertial fusion start-up having raised over £70m and successfully demonstrated fusion in November 2021.

At the start of 2023, First Light Fusion announced plans to build a machine that will prove its target-based approach goes a step further. Rather than solely achieve fusion, Machine 4 will be First Light’s demonstrator facility intended to show ‘gain’. Once developed, Machine 4 will become the largest pulsed power facility in the world, creating a brand-new science platform for UK R&D in several sectors.

Target-based fusion

Fusion differs from today’s nuclear fission by seeking to fuse together atoms rather than split them. With fusion, the key is to combine tritium and deuterium which have five hydrogen neutrons between them. When fused, they become helium 5 for the tiniest fraction of a second before shedding one of the hydrogen neutrons to become the more stable helium 4. This releases a significant amount of energy which scientists believe, if it could be controlled at scale, would provide a clean and abundant energy source that could replace the planet’s reliance on fossil fuels.

The approaches to achieving fusion are split into two main camps. The first approach is to suspend a ball of plasma, as hot as the sun, using powerful superconductive magnets. The other, which First Light Fusion is pursuing a version of, is to fire a projectile, or a laser, at a capsule holding the tritium and deuterium. This is called inertial confinement fusion and would be more cost-effective.

There are several groups around the world seeking to achieve fusion through an inertial approach, but First Light’s differentiator is that it leverages a key piece of proprietary technology, which it calls the target. Dr Hawker explains that First Light Fusion’s approach is unique in focussing on the design of the target which amplifies the force of the projectile hitting it.

"We think of the target having two parts," he explains. "There's the fuel capsule deep within it, which holds the fusion fuel, the deuterium and the tritium. Then there's what we call the amplifier. The amplifier is our key technology. It’s the part that we've invented and further developed, which no one else has. The projectile hits the front of the amplifier, which focuses the energy of the projectile into the fuel in a way which works for what you need to create inertial fusion.”

The intention is for projectiles to be fired down a cylinder at a target which contains a fuel capsule surrounded by the company’s unique amplifier. The process would be repeated roughly every 30 seconds with the energy created being absorbed into surrounding liquid lithium. The flowing liquid protects the chamber from the huge energy release, neatly sidestepping some of the most difficult engineering issues in other approaches to fusion. This would heat surrounding water to boil, producing steam to drive a turbine.

Launching out of Oxford

The co-founders knew the science was sound and that their first job was to convince investors. One of the early investors was IP Group, and First Light Fusion has since received investment from several large investment groups, including Oxford Science Enterprises, the independent investment company which founds, funds and builds companies from the University of Oxford.

Dr Hawker points out that coming from the University of Oxford does not guarantee investment, but it did help the fledgling business get through the door as he and Professor Ventikos toured the offices of venture capitalists across London.

“Oxford’s academic reputation opens doors. The brand, University of Oxford, still gets us meetings. It's instant name recognition. Talking to investors from the Middle East, from China or the US; they all know who the University of Oxford is. It's a huge advantage.”

International cooperation

While Oxford links helped with introductions to early financiers, they were also instrumental in building lasting partnerships with leading academics, including American cavity collapse expert and Engineering Science Head of Department, Professor Ron Roy, and fellow American and serial entrepreneur, Bob Dean. Sadly, Dean has since passed away, but Professor Roy remains an advisor to the company.

Professor Roy was a Visiting Professor at Oxford when he originally met Professor Yiannis Ventikos several years before First Light Fusion was formed. As an expert in cavity collapse, he had many informal discussions before later becoming a consultant to the business

This international exchange of ideas proved so attractive, Professor Roy decided to move to the UK permanently, taking up the position of Chair of Mechanical Engineering in the Department of Engineering Science at the University of Oxford. He believes one of the reasons that spinouts, such as First Light Fusion, can flourish, is that the University attracts so many talented people from many engineering disciplines who can all work under the same roof.

This has been important for First Light Fusion because, although it does not limit itself to working solely with Oxford academics, it has a strategy of focussing on single challenges and then finding the world-leading experts that can help to overcome them. Professor Roy explains, "Oxford’s different because it has its history and its reputation, but it’s truly a very international place" he says. “Our department is unusual for having academics, researchers and students from all disciplines of engineering, all under one roof, in one department. The vast majority of universities would have people in discrete departments which means collaborating is not as easy. It’s one of the reasons people come here, you can expand your horizons very efficiently."

Machine 4 designed to show gain

There have been encouraging developments for researchers pursuing a target-based approach to fusion. In December 2022, the National Ignition Facility (NIF), at the Lawrence Livermore National Laboratory in California, demonstrated ‘gain’ for the first time. It created 1.5x the energy it took to produce the fusion reaction, making a milestone in the progression of target-based approaches. In a bid to follow suit, First Light Fusion is working with the UK Atomic Energy Authority (UKAEA) to build its Machine 4 at its Culham site in Oxfordshire. Professor Sir Ian Chapman, CEO at UKAEA, is hopeful that it will open a new frontier in the pursuit of fusion. “We have enjoyed a long relationship with First Light Fusion as it has progressed its unique projectile fusion method, and worked with them to validate their maiden fusion result in 2022. First Light joins other fusion pioneers in working at Culham as we continue to drive UK economic growth and a thriving fusion industry.” Professor Sir Ian Chapman Work on building the machine is expected to begin in 2024 with the potential for First Light Fusion to possibly demonstrate gain by the end of the decade.

Reproduced with kind permission of the University of Oxford https://oxford.shorthandstories.com/innovation-first-light-fusion/index.html