London; September 2026: Following the Global Fusion Policy Summit held at Mansion House in London today (Monday – 14th September 2026), the United Kingdom Atomic Energy Authority (UKAEA) and the United States Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) have joined forces to link their advanced fusion supercomputing platforms, using artificial intelligence to accelerate fusion energy’s development.
At the Global Fusion Policy Summit held in London today (14th September 2026) UKAEA and PPPL, the UK’s and one of the US’s leading national fusion laboratories, signed a Joint Declaration of Intent to explore linking UKAEA’s SUNRISE mission-focused AI supercomputer with PPPL’s STELLAR-AI platform through a partnership known as the SUNRISE–STELLAR-AI Federation.
The Global Fusion Policy Summit aims to increase regulatory harmonisation, crucial to achieve safe and secure fusion energy, and create certainty for developers and investors. The federation would connect UKAEA’s SUNRISE fusion-focused supercomputer with PPPL’s STELLAR-AI platform, enabling researchers on both sides of the Atlantic to train AI models on results from both national laboratories and develop AI tools for future fusion power plants.
The collaboration would draw on experiments completed using UKAEA’s MAST Upgrade facility in Oxfordshire and PPPL’s NSTX-U facility in New Jersey. The federation will mean both advanced computers will be used to train the same AI models, which need large volumes of high-quality data to make accurate predictions.
By combining supercomputing power and expertise, the federation aims to shorten the design cycle for future fusion power plants, make better use of existing experiments, and give the next generation of fusion scientists on both sides of the Atlantic a shared platform to build on.
Joe Milnes, Executive Director for Engineering and Computing at UKAEA, said: “Fusion is one of the great scientific and engineering challenges of our time. To solve these challenges, fusion needs partnerships. The US and UK are two global leaders in fusion research, and the federation of SUNRISE and STELLAR-AI would build on a long history of transatlantic cooperation to further advance fusion development”.
Jonathan Menard, Chief Scientist at PPPL, said: “A fusion power plant is one of the most complex machines humanity has ever tried to build and no single laboratory or nation will design it alone. By federating the SUNRISE and STELLAR-AI computer platforms, we can train AI on data from two leading fusion facilities, test ideas across two of the most capable computing systems in the world that are designed for fusion research, and accelerate the path to a compact fusion power plant”.
Both MAST Upgrade and NSTX-U are compact spherical tokamaks with similar designs, making them well suited for joint AI training. Models built using data from a single machine can struggle to make accurate predictions that apply across different machines.
When different facilities are combined, researchers can develop more powerful machine-learning models that better capture the underlying physics and help accelerate future fusion projects, including the UK’s Spherical Tokamak for Energy Production (STEP Fusion) and US concepts such as PPPL’s Spherical Tokamak Advanced Reactor (STAR).
The federation wants to also develop the next generation of fusion and AI experts through training, workshops, research opportunities and other international collaborations.
Rob Akers, Director of Computing Programmes and Senior Fellow at UKAEA, said: “UKAEA and PPPL would draw on experimental data from two world-leading fusion machines, using simulation to fill the gaps and extend those datasets into regimes we have yet to explore. Together, we can develop digital twins of both machines to support the design of future fusion power plants, creating models of spherical tokamaks that are more predictive, more actionable and ultimately more useful to fusion engineers”.
Akers has asserted further – “The real power will come from working as one team. Together, we can learn faster and learn more, extracting maximum insight. The computing and international collaboration will help us accelerate the journey from today’s experiments to tomorrow’s fusion power plants”.
Shantenu Jha, Head of Computational Sciences at PPPL, said: “Our goal is to let models and experiments move freely between the two systems. We will turn a collection of supercomputers into a single engine for fusion discovery”.
Advancing fusion through supercomputing platforms –
SUNRISE is the UK’s first AI supercomputer dedicated to fusion energy, backed by £45 million from the UK government. It forms the first phase of computing infrastructure underpinning the UK’s first AI Growth Zone, established at UKAEA’s Culham Campus. STELLAR-AI is PPPL’s AI and high-performance computing platform, operated with support from Princeton University.
Following the Global Fusion Policy Summit held at Mansion House in London on 14 September 2026, UKAEA and PPPL have discussed possible next steps for the federation, which include exploring the development of digital twins of both facilities.
A digital twin is a detailed virtual copy of a real fusion machine, supported by regular data from fusion experiments, so researchers can test changes and predict how the machine will behave in software before applying experiments to hardware.
Researchers will also examine how to move computing jobs smoothly between platforms, which use different hardware, so scientists can pick the right supercomputing platform for each problem.
Team Maverick.
