Supercomputer cluster planned for site of shut-down European fusion reactor

The UK Atomic Energy Authority (UKAEA) is planning to establish a new data centre cluster on the site of a closed European fusion research lab.

Earlier this year, the Joint European Torus (JET) closed its doors after 40 years of operation. Once the most advanced fusion experiment in the world, its final act was the breaking of a world record for the most amount of energy ever produced by a fusion machine (69 megajoules over five seconds - which is about enough to heat four or five baths).

Now, the UKAEA is looking for partners to move onto the site of the European facility and has published a tender for a "Mission-led AI & Simulation Supercomputing Centre."

In addition to innovative fusion energy startups, the site is expected to become home to "large-scale data centres in support of the unprecedented growth in the AI/ Tech and adjacent sectors."

The UKAE said the opportunity may interest "data centre hosting organisations, cloud service providers, industrial HPC / AI users, OEMs within the HPC supply chain and other forms of private investment." Plots ranging from 4,000m2 to 38,000m2 are available.

Sited in Abingdon, Oxfordshire, (which we hope will come to be known as AIbingdon), the UKAEA's Culham Campus has available power supplies that are capable of delivering 575MW peak and 144MW steady state capacity,

"The lease-hold value of these plots as well as the power infrastructure is substantial," the UKAEA wrote.

"Culham Campus has a range of green and brown field plots suitable for hosting large scale data centres in support of the Government’s mission to be a leading player in Artificial Intelligence and supercomputing," it continued. "These disruptive technologies underpin UKAEA’s fusion roadmap but will also be essential for other applications targeting Net Zero (e.g. battery technology, off-shore wind turbines, Small Modular Reactors, Fly Net Zero etc.)."

In 2023, more than 750 people signed a petition against the planned closure of the JET. Its fate was long planned, although talk on the facility's future stalled as the UK and EU struggled to strike a deal after Brexit.

The JET Torus will be replaced by the International Thermonuclear Experimental Reactor (ITER) in France, which is due to open in the mid-2030s and will be the largest fusion reactor in the world.

The UK turned down an opportunity to join this historic project - even though it originally planned to remain an ITER member after Brexit.

Industry figures are now urging the Labour government to take urgent action to help Britain maintain its lead in the race to develop fusion power. It remains to be seen whether its strategy includes rejoining ITER.

Other projects taking place in the UK currently include the Spherical Tokamak for Energy Production (STEP), a prototype fusion powerplant being built in Nottinghamshire, as well as the Mega Amp Spherical Tokamak Upgrade (MAST-U), a spherical tokamak design project focused on fusion energy efficiency, and Tritium Fuel Cycle (formerly H3AT), the UK’s leading facility in tritium (a critical element in creating fusion), both are which are now fully operational at Culham.

All in all, the grounding of JET will take several decades, with decommissioning and repurposing work expected to continue until 2040.

Fuelling fusion and AI compute demand

The goal of the UK's current fusion strategy is to make a commercial grid-ready fusion reactor by 2040. If successful, it will deliver safe, sustainable, low-carbon energy by combining two different types of hydrogen molecules and heating them to high temperatures that cause them to release and generate energy.

The UKAEA tender offers to work with partner organisations "for the explicit purpose of growing a cluster of facilities and tenant organisations to accelerate the UK’s mission to deliver fusion power to grid in the 2040s." Upgrade works will provide the Callum Campus with a dual-supply resilient connection to the National Grid by mid-2026.

Along with propelling the fusion strategy goal, the tender also presents an opportunity to build a supercomputing cluster that's well-connected and close to London.

Gareth Wilson, the UK lead at DDN, an AI data company, told The Stack that the UK now "lags well behind our European counterparts in supercomputing and AI at scale."

"Systems of this scale are urgently needed to perform the multitude of fusion energy simulations required to advance research towards getting fusion, the cleanest form of energy, on the grid by 2040," Wilson said.

"Currently, we see large volumes of data being discarded, cutting datasets down to make workloads fit into the existing computing and storage resources. This hinders the progress of our scientific output."

See also: Can AWS really reduce the carbon footprint of AI workloads by 99% or is it 'greenwashing'

Alex McMullan, International CTO at Pure Storage, said that the UK needs "sustainable and efficient infrastructure that doesn’t just save money but also optimises the current data centre footprint in the UK."

He warned that "organisations have failed to fully understand AI’s power demands and subsequent impact on their sustainability commitments."

"Addressing overall power consumption and cooling issues is not an optional addition to this tender- it’s a vital inclusion if organisations are to have any hope of meeting ESG targets," he said.

The newly elected British government has made Net Zero and increasing compute capacity focal points of its priority projects. However, the conflict between data centres and limiting emissions remains unresolved.

Robert Ferry, Environmental Design Director at the design consultancy BDP, told The Stack: “One of the biggest challenges facing the ever-growing data centre world is meeting the requirement for the huge power demands in a sustainable way. It’s a particularly acute issue in the UK because of the drive towards Net Zero Carbon and the rapid uptake of heat pump technology. The grid simply cannot keep up.

"The Culham Campus proposal is an interesting one because of the symbiotic relationship between the sustainable power for the data centres that could be provided via the UKAEA’s nuclear fusion programme and the processing power those data centres could provide to advance the UKAEA research in the fusion field. It is definitely something the UK requires, the only question is – will the 100MW power supply being initially offered be anywhere near enough?"

A UK Atomic Energy Authority spokesperson said: “UKAEA is evaluating how newly available land and infrastructure might be used in partnership with industry to deliver a mission-led AI & Simulation centre.

"UKAEA is currently seeking calls for interest. While UKAEA cannot comment in more detail while the tender process is underway, we encourage industry to express their interest through the prior information notice here."

See also: What do tech leaders want from a new British government?