Reaching for the stars: 60 years
of fusion at Culham


Culham Campus – owned and operated by the UK Atomic Energy Authority (UKAEA) – is a major part of the South Oxfordshire landscape. For local people, it is a well-known sight on the main road east of Abingdon; for more than 3,000 people who work there, it is where they spend a lot of their lives; for scientists across the world, it is famous as home to the JET experiment and as an international centre of research in the exciting field of fusion energy.​

It has been all of these things for 60 years, formally opening in September 1965.​

This web page is a walk down memory lane, exploring Culham before it was a science centre, and looking at how the campus has changed since 1965 – the research projects, social life, buildings, the famous faces of those who have visited and more. ​

Here’s looking forward to the next 60 years!

What is Fusion

The sticking together, or ‘fusion’, of atomic nuclei is what makes the Sun and all the stars shine – the power source of the universe. ​

By copying this process, we can use fusion here on Earth to give us abundant low-carbon energy for a sustainable future. It’s a technology with the potential to change the world, and South Oxfordshire is at the heart of it.​
Fusion involves heating a gas of hydrogen-based fuels to temperatures ten times that of the Sun. In this hot gas, or ‘plasma’, fusion reactions happen and energy gets released.​

One of the best ways to do fusion is in a machine called a tokamak, which holds plasma in a ring- shaped container using magnetic fields. ​

As the UK’s centre for fusion research, Culham Campus has been home to many experiments, focusing on tokamaks in recent years. ​

The work is now paying off, with plans for the country’s first full-scale fusion plant (STEP Fusion) well underway – scheduled to start up around 2040.

THE
CULHAM SITE

The story of Culham Campus starts well before 1965. In 1930, Major George Allen first used a field west of Clifton Hampden to land his plane, and built small hangars to support his passion for flying. It was soon added to the AA list of approved landing grounds for the growing pleasure-flying community.​

As World War II started, many landing grounds were requisitioned for military airfields, and Culham was no different. Royal Naval Air Station Culham (aka HMS Hornbill) opened in 1944, with three runways and hangars and billets surrounding the airfield. You can still see the hangars at Culham No.1 Site next to
Culham railway station.​

The airfield closed in 1953, and when UKAEA needed a home for the growing fusion research programme (then based at Harwell), the disused site was an obvious choice. ​

Construction started in 1962, and the lab was opened in 1965 by well-known writer and scientist C.P. Snow, who was then Minister for Technology. ​

Squadron of Supermarine Seafires, based at Royal Naval Air Station Culham / HMS Hornbill.​
Plan of the RNAS Culham airfield, showing the hangars and barracks.  No. 1 site is still standing, as industrial units around Culham station, but nos. 2-5 sites and Pegasus and Argus Camps have all but disappeared.​
Aerial photo of RNAS Culham in 1944.​
Aircraft mechanics posing on a Fairey Firefly at RNAS Culham.
Construction of RNAS Culham.​
A low flying De Havilland Mosquito, performing at an air display at RNAS Culham.​
Construction of Culham Laboratory in 1963.​
Installation of a specially-commissioned sculpture for the opening of the lab in 1965. ‘Plasma Stabile’ was created by Geoffrey Clarke, a leading British post-war artist best known for his work at Coventry Cathedral.

BUILDINGS

The buildings at Culham Campus have changed over 60 years to suit the needs of fusion research. Big experimental halls sit alongside workshops, research labs and office accommodation.​

Some of the original lab buildings (often likened to a 1960s polytechnic!) remain, but have been joined by super-modern, climate-controlled open plan offices and state-of-the-art technology centres.​

Within the buildings, things are different too. From typing pools with no computers to docking stations for laptops at each desk and many staff working partly from home. From a library where physicists would hunt for scientific papers and books… to online journals available at the click of a mouse. From smoke-filled tea rooms to kitchens with dishwashers in each suite of new offices.​

The laboratory was laid out with courtyards akin to Oxbridge ‘quads’ – supposedly to attract top scientists from colleges at Oxford and Cambridge and make them feel at home!
The entrance to the main ‘E’ block is largely unchanged from this photo and contains the original (much refurbished) lecture theatre; scientists still use the original ‘D’ buildings, often unkindly compared to a polytechnic or 1960s secondary school.​
The past decade has seen a host of new buildings at Culham as the fusion programme accelerates: the RACE robotics centre; the Oxfordshire Advanced Skills apprenticeship school, with capacity for over 300 trainees; a world-first fusion fuelling and technology research hub; and a Materials Research Facility.​
A new reception and visitor centre is the latest addition to the campus, opened in 2025. 

FAMOUS FACES

The Culham site has hosted visits from many tens of thousands of people over 60 years – school students, general public, academics, fusion researchers, industry and more from all over the world. But it is the famous faces that often capture the imagination – from prime ministers to royalty; TV celebrities to captains of industry. Culham Campus has opened its doors to them all …​

Queen Elizabeth II and France’s President Mitterand arrive at JET to officially open the facility in April 1984.​
King Charles III (then The Prince of Wales) at JET in 2022 to celebrate its world fusion energy record.​
Overseas royalty have also visited – Princess Astrid of Belgium joined us and took a few snaps during her tour.​
Rishi Sunak, then Prime Minister, pictured at JET with Energy Secretary Grant Shapps in 2023.​
Former Prime Minister Tony Blair testing his skills at Culham’s Materials Research Facility.​
British astronaut Tim Peake is no stranger to stars – he came to see how we artificially create them in the MAST Upgrade machine.​
Culham has played host to many TV productions over the years, including BBC documentaries by Hannah Fry and Professor Brian Cox.
Brian Cox is pictured watching a plasma in the JET Control Room while filming for BBC’s Horizon programme in 2009.

EXPERIMENTS

As soon as the Culham site opened, scientists started building a variety of fusion experiments. During the 1960s and early 1970s, UKAEA explored a number of concepts – linear pinches, reversed field pinches and stellarators. With weird and wonderful names – TARANTULA, PHEONIX, CLASP to name just a few – they were scattered all over the D, E and F experimental halls on the campus. ​

When the tokamak started to take off in the 1970s, UKAEA moved to concentrate on these machines (TOSCA, DITE, COMPASS), and hosting and operating JET of course. ​

In the 1990s, the promising ‘spherical tokamak’ concept, offering high performance in smaller machines, emerged. The START experiment was built for just a few hundred thousand pounds, out of spare parts, to test its credentials. START went from strength to strength, breaking many scientific records. This led to the ground-breaking MAST and MAST Upgrade experiments – they now form the basis of the design for STEP Fusion, which will be the UK’s prototype fusion powerplant when it’s built in the 2030s.


The ISIS plasma injector pictured in 1969.​
Tarantula – a 1960s apparatus that used shock waves to heat plasma.​
A 1974 team photo at the Superconducting Levitron machine, which used a superconducting ring to trap plasma.​
TORSO investigated the effect of plasma shape on performance in the 1970s.​
During the 1970s and 1980s, the Divertor Injection Tokamak Experiment (DITE) pioneered methods of removing excess heat and impurities from fusion machines.​
The Small Tight Aspect Ratio Tokamak (START) was the world’s first spherical tokamak, and demonstrated record-breaking plasma performance and efficiency when it started in 1991.​
The Mega Amp Spherical Tokamak (MAST followed by MAST Upgrade) built on the huge success of START – cementing the spherical tokamak as a viable option for future powerplants. This has paved the way for the UK’s fusion powerplant programme STEP Fusion.
MAST Upgrade was launched in 2020 and has already run almost 10,000 plasma tests.

JET Europe comes to Culham

For many in the community, the Joint European Torus (JET) is intrinsically linked with Culham. The distinctive white building that houses the project is visible for miles around. Ever since construction in the 1970s, JET brought people to the area from all parts of Europe, and even helped to found a local school (which continues to thrive as Europa School UK).​

JET was an ambitious endeavour, borne out of the global oil crisis of the early 1970s, for Europe to build a large experiment that could demonstrate fusion at close to the scale of a power plant. In its 40 years of operation, JET did just that – setting a series of world firsts and performance records along the way.​

Throughout, what stood out was the teamwork – between engineers and scientists, between nationalities, on site and in recent years more remotely. ​

Since operations finished in 2023, JET has entered a new era as a pioneer for the decommissioning of fusion machines. Over the next couple of decades, it will be safely dismantled and the knowledge gained will help the designers of future fusion power plants.​

A true scientific success story from Culham to the world.

The​ main JET building has been a feature of the Oxfordshire landscape for over 40 years. As wall as being functional, it is striking in its design and won a Royal Institute of British Architects award when first constructed.​
The​ JET design team was based at Culham from the mid 1970s onwards. Sitting at the front is Paul-Henri Rebut, JET Deputy Director, who is credited with masterminding the project.​
JET Director, Hans Otto Wüster and UKAEA’s Culham Director, Bas Pease, unveil a sign at the site entrance, formally marking the decision to construct JET at Culham in 1978.​​
JET was constructed between 1978 and 1983 – on time and within budget: 300 – 400 million European Currency Units (forerunner of the Euro).
The first ‘plasma’ in JET was achieved on 25 June 1983. Keenly looking at the multimeter that detected it are the JET team with Hans-Otto Wüster, front and centre.  With little in the way of available computing, a control room wouldn’t appear for some years to come.​​
In the early years, JET’s main chamber was maintained  manually.  Subsequently, semi-automated ’remote handling’ technology was routinely used for maintenance and upgrades. 
An aerial shot of the JET machine in 2010, showing the multitude of pipes, cables, diagnostics, heating systems and cranes. The main fusion chamber is buried deep inside this labyrinth of equipment. ​
Although based in the UK, JET was an experiment for all of Europe. Many European scientists and engineers moved to Oxfordshire – and some have never left! Several hundred scientists a year would relocate to Culham for weeks or months at a time to plan, run and analyse experiments.
In 1997, JET ran tests with the optimum fusion fuel mix, and set a world record 16.1MW of fusion power – a record that still stands today. Here, scientists in the control room are looking keenly at the data from this famous test.​
JET was unique amongst fusion machines in many ways; not least its flexible and adaptable remote handling system, called MASCOT. Here, it can be seen working in the JET chamber.​
In the last few months of operation, JET pushed to sustain fusion reactions at higher performance, and set a world record of 59 megajoules of fusion energy over 5 seconds. Here, scientists celebrate the achievement of these results.​
When JET ran its last experiment in December 2023, it had operated for over 40 years, conducted over 100,000 tests and transformed understanding of fusion internationally. A celebratory party was held for ex-JET staff in February 2024 – all of them proud of the part they played in such a unique project.
The distinctive twin columns of the white JET building house giant concrete beams – weighing over 1000 tonnes each – that can be moved up and down to allow cranes to work on the machine.

COMPUTING

Sixty years is a long time in many aspects of life, but especially so in IT and computing. We are so used to having immense computing power in our laptops and mobile phones, it is difficult to imagine life when this wasn’t available …​

From the mid 1960s, large mainframe computers began to be used for modelling and simulation of the plasma inside fusion machines, but personal computing
(email, word processing, data tables) was still in the future.​

Remarkable when you look at JET, to think that it was designed in a purely analogue way – using drawing boards, rulers and pencils. Computer Aided Design (CAD) did not take over until the mid 1990s.​

Today, supercomputers and artificial intelligence allow us to predict the incredibly complex physics of fusion reactions, and help us to develop new materials and engineering components for fusion power plants.​

Such a quantum shift – what will computing look like in another 60 years’ time? ​

The first computers at Culham were only used for scientific calculations. They were housed in dedicated rooms.​
Before there was email and the internet, there were fax machines, and before fax machines, there were Telex machines – enabling scientists to communicate with international colleagues. ​
Scientific calculations were plotted in computer rooms like this one and printed out on large sheets of paper for analysis. State of the art technology in the mid 1960s.
Well before staff had PCs and used email, computers were used to control tokamaks, such as COMPASS in the 1980s. An innovative new technology was adopted in the COMPASS control room – the touch screen! ​
Virtual reality and the use of ‘digital twins’ mean that we can map and navigate fusion plants without needing to go inside them.​
Scientists now have access to computing power that models the intricate physics of fusion plasmas, producing highly accurate simulations that help us design future machines.​
A data centre at JET stores the information from over 100,000 tests from 40 years of operations. Reassuringly, we still back up data on to tapes and courier them to Harwell for storage on a weekly basis!
Culham’s Materials Research Facility analyses samples of metal that are thinner than a human hair, magnifying them 200 million times so we can analyse their properties.

NATURE AND WILDLIFE

Despite the recent transformation of the campus with new buildings, there are still lots of green areas, trees and nature to enjoy. ​

The many hundreds of trees on site are down to the first director of Culham Laboratory – Sir John Adams, who was later Director of CERN. He was a great advocate of green spaces, and insisted on the trees being planted when the site was constructed in the 1960s; many date back to these early days.​

And the people who now work at the site share it with many plants and animals, some of them snapped by staff in recent years…

Around 60 mature trees were brought from nearby locations, including Nuneham Courtenay and Harwell, and transplanted at the campus, as seen in this 1965 photo.
Credit Pauline Lawrence​
Unknown photographer!​
Credit Jane Ambler​
Credit Andrew Ashe​
Credit UKAEA

NOT JUST FUSION

The main focus at Culham Campus has always been on fusion, but other work has been conducted in a number of interesting areas.​

In the early days of the site, scientists built instruments that were mounted onto the UK’s Skylark rockets, which measured the Sun’s corona in more detail than ever before.​

In the 1990s, AEA Technology was formed out of UKAEA to explore commercial research opportunities, some of which were based at Culham. One notable example was the Culham Lightning Test Unit, which simulated the impact of lightning strikes on aircraft components. ​

Hi-tech business is still flourishing at Culham, with a thriving innovation centre for start-ups, and many tenant companies based on site in recent years – undertaking driverless car testing, work on prosthetic limbs and hypersonic propulsion to name just a few.
​
And with the UK’s ambitious plans for commercial fusion energy gathering pace, the campus is at the heart of a growing ‘cluster’ – attracting developers and suppliers from home and abroad.

Culham scientists built instruments for the pioneering Skylark rocket missions of the 1960s.​
Preparing for a test at the Culham Lightning Studies Unit. This work made planes safer and advised industry on protection and certification. ​
One major tenant at Culham was Reaction Engines, who investigated the viability of hypersonic flight.​
Luffy AI is one of the start-up companies now flourishing at Culham, developing new approaches to industrial control systems from its premises on the campus.

Life at Culham Campus

Away from the research, the more social side of life at the campus has always been important.​

With so much green space, sport has always played a big part in staff unwinding – archery and cricket have made way for softball tournaments and a new on-site gym. Firework displays and Christmas parties have been joined by our ‘Culhambury’ staff festival. Tea rooms and the social club have been replaced by pizza ovens and coffee shops.

Smart UKAEA chaffeurs stand proudly alongside their Austin Maxis and Wolsey 2200s in 1973.​
The Culham restaurant in the mid 1960s. Highlight of the menu was mixed grill, costing 3 shillings and 6 pence.​
The staff children’s Christmas party was a regular event in Culham’s calendar for many years.​
Archery was a popular pastime for staff, making the most of Culham Campus’ open spaces
A cricket match underway on the campus in 1968.
In more recent times, staff receptions and the Culhambury music festival have enabled staff to let their hair down.
Replacing archery and cricket are the on-site gym and softball tournaments.

THE FUTURE

So what is the future for fusion and the Culham Campus? The closure of JET after 40 successful years was an emotional occasion, but Culham had already started to adapt and expand as fusion entered an exciting new era.

In the last ten years, new experiments and facilities have sprung up to solve the major technology challenges for building a fusion power station. These include the innovative MAST Upgrade tokamak; the RACE robotics centre exploring remote maintenance systems; a Materials Research Facility developing structural materials; the H3AT fuel research centre; and facilities to design and test fusion components and manufacturing methods.​

The ultimate aim is fusion electricity production, and this took a major leap forward in 2018, as UKAEA started the design of STEP Fusion – a prototype fusion power station to put fusion electricity on the UK grid in the 2040s. Whilst it will be built at West Burton in Nottinghamshire, hundreds of scientists and engineers contributing to this ground-breaking project are based at Culham. ​

Culham Campus has led worldwide fusion research for the last
60 years – and will continue to do for decades to come. ​


All of the work at Culham since 1965 has, in many ways, ​been leading to the design of the UK’s Spherical Tokamak for Energy Production (STEP) fusion powerplant.  The STEP Fusion team are largely based at Culham, but preparatory work at the construction site at West Burton has already started.