Fusion is progressing, and the challenge is moving: from the laboratory to engineering. This change of pace is due to digital technology and AI, which compress years of validation into a few hours of calculation.
As the planet seeks to move away from fossil fuels, nuclear fusion is coming back to the forefront. Long perceived as a physicist’s dream, it is today becoming a strategic challenge: producing clean, safe and almost unlimited energy. To achieve this, we must master extreme physical conditions that only digital engineering can anticipate.
The dream of the Sun on Earth
Fusion does not divide atoms, it unites them. Unlike fission – the principle of current nuclear power plants – it combines two light nuclei to form a heavier one, releasing colossal energy, like at the heart of the Sun. This reaction produces neither CO₂ nor long-lived radioactive waste. But it imposes a dizzying challenge: in a tokamak for example, the plasma must be heated to more than 150 million degrees Celsius and kept stable in magnetic fields of exceptional power.
This feat is based on decades of scientific research and unprecedented computing power. France plays a major role: the ITER project brings together 35 nations in Saint-Paul-lès-Durance, and the WEST tokamak recently broke a world record for confined plasma duration. These successes are a reminder that energy sovereignty is won through innovation.
Design the impossible
In a fusion reactor, each parameter counts: geometry of the magnetic coils, plasma turbulence, resistance of the materials to the neutron flow. Testing each hypothesis in real conditions is unfeasible. Digital simulation has become the key to accelerating this revolution.
It models plasma behavior, predicts mechanical and thermal stresses, tests the strength of materials and optimizes the design before construction. Using high-performance computing, engineers explore thousands of scenarios in just a few hours, identify instabilities and refine the tokamak design. This approach reduces risks, concentrates resources and transforms research into predictive engineering: errors cost less, cycles shorten.
These technical advances are no longer limited to laboratories: they enter into the global competition for energy power.
A global race for the energy of the future
Fusion is no longer an isolated dream but a global competition. In the United States, public and private actors, from Lawrence Livermore National Laboratory to Commonwealth Fusion Systems, are claiming major breakthroughs. In China, the EAST reactor maintained plasma at more than 120 million degrees for several minutes. The United Kingdom is developing its STEP demonstrator, while Japan and Korea are accelerating their own programs.
Despite this progress, most forecasts – including those of the European Commission – estimate that no fusion reactor will produce electricity before 2050. The road remains long, strewn with technical, economic and regulatory obstacles. But each step brings the merger closer to industrial reality, and simulation plays a decisive role here: it makes it possible to learn, optimize and accelerate even before the first plant.
Merger is becoming a strategic priority everywhere. Europe occupies a leading position, strong on its scientific excellence, its industrial know-how and its tradition of cooperation, illustrated by projects like ITER. In this dynamic, simulation remains the keystone of the speed, reliability and safety of large-scale developments.
Europe in energy recovery
To achieve carbon neutrality in 2050, the European Union plans to increase its installed nuclear power from 98 to 144 gigawatts, in particular thanks to SMRs (Small Modular Reactors). France, which already gets nearly 70% of its electricity from fission, is once again becoming a locomotive.
But competitiveness will also be played out in the digital arena. Simulation makes it possible to design safer reactors, optimize maintenance of the existing fleet and extend the lifespan of installations. It accelerates the design of SMRs, these modular, compact and more flexible reactors, adapted to specific regional or industrial needs.
This link between virtual design and industrial reality marks a shift. Connected digital engineering – from advanced scientific research to virtual prototypes, and from calculation to construction – is becoming the basis of a new technological revolution. And this approach goes beyond nuclear power: it is already at work throughout the energy sector.
When artificial intelligence accelerates fusion
The next revolution is taking place at the intersection of simulation and AI. Machine learning analyzes masses of data to improve the accuracy of physical models and detect irregularities invisible to the human eye. Digital twins predict material wear, adjust operating parameters and optimize performance in real time. This AI-simulation convergence accelerates R&D processes that took years. Engineers can now evaluate the behavior of reactors in extreme situations before any physical test. Fusion is thus progressing both in laboratories and in supercomputers. They can also merge test data with physical models to refine them. These models are then used to train AI that can execute scenarios in real time, hundreds of times faster.
A global technological project
Fusion is no longer just a scientific ambition but a global collective effort, guided by innovation and technological mastery. Transforming this vision into industrial reality requires collaboration, continuity of investment and precision digital engineering.
For France and for Europe, success will require a close alliance between public research, industry and digital innovation. Simulation is its backbone: it links theory, experimentation and production. It is in the precision of models and the power of calculation that the European energy future is already being written.
