First plasma in new reactor brings the UK a big step closer to fusion energyOur news
28 April 2017

First plasma in new reactor brings the UK a big step closer to fusion energy

Tokamak Energy turns on the ST40, its third reactor in five years

The reactor will reach 100m degrees in 2018, the temperature required for fusion

ST40 is the third stage of a five stage plan that will deliver fusion energy into the grid by 2030

The UK’s newest fusion reactor has been turned on for the first time and has officially achieved first plasma. The reactor aims to produce a record-breaking plasma temperature of 100 million degrees for a privately-funded venture. This is seven times hotter than the centre of the Sun and the temperature necessary for controlled fusion.

The tokamak reactor, entitled the ‘ST40’, was built by Tokamak Energy, one of the world’s leading private fusion energy ventures. The Oxfordshire-based company grew out of the Culham Centre for Fusion Energy and was established in 2009 to design and develop small fusion reactors. Tokamak Energy’s aim is to put fusion power into the grid by 2030.

With the ST40 up and running, the next steps are to complete the commissioning and installation of the full set of magnetic coils which are crucial to reaching the temperatures required for fusion. This will allow the ST40 to a produce plasma temperature of 15 million degrees – as hot as the centre of the Sun – in Autumn 2017.

Following the 15 million degree milestone, the next goal is for the ST40 to produce plasma temperatures of 100 million degrees in 2018. This will be a record-breaking milestone, as the plasma will reach a temperature never before achieved in a privately owned and funded fusion reactor. 100 million degrees is an important threshold, as it is only at or above this temperature that charged particles which naturally repel can be forced together to induce the controlled fusion reaction. It will also prove the vital point that commercially viable fusion power can be produced in compact spherical tokamaks.

Tokamak Energy’s journey to generating fusion energy is moving at a rapid pace; the company has already reached the half-way point of its plan to deliver fusion power. It is focused on working with a smaller reactor design – called a compact, spherical tokamak – that enables quicker development of devices, therefore speeding up the process towards achieving their ultimate targets: producing first electricity by 2025 and commercially viable fusion power by 2030. Tokamak Energy’s research has also proven that this route to fusion power can be much faster than the development of conventional large-scale tokamak devices.

Dr David Kingham, CEO of Tokamak Energy, commented: “Today is an important day for fusion energy development in the UK, and the world. We are unveiling the first world-class controlled fusion device to have been designed, built and operated by a private venture.  The ST40 is a machine that will show fusion temperatures – 100 million degrees – are possible in compact, cost-effective reactors. This will allow fusion power to be achieved in years, not decades.”

“We will still need significant investment, many academic and industrial collaborations, dedicated and creative engineers and scientists, and an excellent supply chain. Our approach continues to be to break the journey down into a series of engineering challenges, raising additional investment on reaching each new milestone. We are already half-way to the goal of fusion energy; with hard work we will deliver fusion power at commercial scale by 2030.”

– Ends –

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Notes for editors:

  1. About Tokamak Energy

Tokamak Energy is a private company working to develop compact fusion power. The firm is led by a team of magnet engineers and fusion experts from globally renowned public and private institutions, and an experienced CEO with a physics research background and over thirty years of high-tech business experience.

Tokamak Energy grew out from Culham Laboratory, which is the world’s leading centre for magnetic fusion energy research and home to the world’s most powerful tokamak, JET, which produced 16MW of fusion power in 1997. Tokamak Energy is particularly focused on spherical tokamaks, pioneered at Culham, because these compact devices can achieve a much higher plasma pressure for a given magnetic field than conventional tokamaks, i.e. they are more efficient.

Adding to this design, Tokamak Energy is deploying high temperature super-conductors as magnets to control the plasma within its devices. These allow high magnetic fields to be created in compact tokamaks, further improving the efficiency of the device. Tokamak Energy has proven the ‘compact, spherical tokamak’ is a viable route to fusion through two of the most widely-read papers in the Nuclear Fusion Journal:


Tokamak Energy is following a five-stage plan towards producing fusion power:

  • Stage 1: Build a small prototype tokamak to demonstrate the concept (the ST25) – achieved 2013.
  • Stage 2: Build a tokamak with exclusively high temperature superconducting (HTS) magnets (the ST25 HTS) – achieved 2015.
  • Stage 3: Reach fusion temperatures of 100 million degrees in a compact tokamak (the ST40), in 2018, followed by further development of the ST40 in 2019 to produce high density plasmas and get close to fusion energy gain conditions.
  • Stage 4: Achieve first electricity with the ‘Fusion Power Demonstrator’ by 2025.
  • Stage 5: Produce commercially viable fusion power with the first ‘Fusion Power Module’ by 2030.


In 2017, Tokamak Energy was selected by the International Energy Agency (IEA) as one of three leading innovative ideas in fusion. It was the only UK representative invited to speak at the IEA’s meeting on developing fusion power, and Tokamak Energy’s CEO Dr David Kingham presented the company’s vision and why it is the most realistic route to fusion power.

Tokamak Energy has raised private investment of £20 million to date, with investors including Oxford Instruments, Legal & General Capital and the Institution of Mechanical Engineers.

Tokamak Energy has an eminent Scientific Advisory Board chaired by Lord Julian Hunt FRS. Members include Professor Jack Connor FRS (one of the most influential theoretical plasma physicists in fusion), Professor George Smith FRS (emeritus professor of materials at the University of Oxford), Professor Bill Lee FREng (Director of the Centre for Nuclear Engineering at Imperial College London) and Professor Colin Windsor FRS (a neutronics and neural networks specialist).

Tokamak Energy has science and engineering offices at Culham and Milton Park, Oxfordshire and a tokamak engineering facility and superconducting magnet development laboratory at Milton Park.


  1. About fusion

Fusion is the reaction that powers the stars. Energy is released when two small particles come together and fuse into one larger particle.  In experiments on Earth, these small particles are the nuclei of deuterium and tritium – types of heavy hydrogen – and they fuse together to make a helium nucleus.  The waste product of fusion is helium, which is perfectly safe.  Fusion produces no greenhouse gases and no long-lived radioactive waste yet it produces vast amounts of energy from very little fuel. The lithium from a laptop battery combined with the deuterium in half a bath of water could supply as much energy at 70 tonnes of coal.  As such it offers a clean, green and plentiful energy solution if it can be harnessed on Earth.

For fusion reactions to happen the deuterium and tritium must be very hot, so that the particles are moving so fast that if they collide they will overcome the mutual repulsion they feel for each other and get close enough to fuse. At JET, the world’s largest operating tokamak, which once produced 16MW of fusion power, the fuel is heated to more than 100 million degrees – 7 times hotter than the centre of the Sun!  Tokamak Energy, based just 5 miles away from JET, is now aiming to achieve this temperature in much smaller, cheaper tokamaks.

Magnetic fields are used to keep the superheated fuel (now an electrically charged gas called plasma) from touching the walls of its container and so keep it hot enough for fusion to occur.  If the plasma does hit the wall it is not dangerous, it just cools down and everything stops.  The specialised machines used for fusion are called ‘tokamaks’.


  1. About tokamaks

‘Tokamak’ is a Russian acronym that stands for toroidal chamber magnetic coils, which concisely describes the machine – a toroidal (doughnut-shaped) vessel with magnetic coils to trap and control the plasma.  When they were introduced in the 1960s, tokamaks showed dramatically improved performance over the other methods being investigated. They heated and trapped the fuel much better than other approaches such as pinches. Tokamaks were rapidly adopted by many international research teams and have remained the front runners in fusion research ever since.

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