ITER Fusion Project Enters Crucial Phase in France’s Quest for Energy

The International Thermonuclear Experimental Reactor (ITER) project in southern France has entered a significant phase as it embarks on the final assembly of its reactor core. This ambitious initiative aims to replicate the sun’s nuclear fusion process on Earth, offering the potential for a clean and virtually limitless energy source. With this project, scientists hope to harness nuclear fusion, the same process that powers stars, which involves fusing hydrogen isotopes to release vast amounts of energy.

To achieve this, ITER will heat hydrogen isotopes known as deuterium and tritium inside a specially designed vacuum chamber called a tokamak. This chamber will contain plasma heated to an astonishing 150 million degrees Celsius. If successful, the energy produced could be up to 4 million times greater than that generated by burning coal, using fuel that can be sourced from seawater.

Precision Engineering and Major Milestones

The current construction phase requires meticulous planning and precision. The Westinghouse Electric Company, a major player in the nuclear energy sector, has secured a $180 million contract to oversee the assembly of the reactor core. Engineers will weld together nine enormous steel sectors, each weighing approximately 400 tons. The alignment of these components is critical, with tolerances as tight as 0.25 mm required to ensure proper function.

Once assembled, these sectors will form the tokamak, which must be both heat-resistant and capable of containing extreme conditions necessary for nuclear fusion. To support this, scientists are developing an advanced magnetic system featuring a 3,000-ton magnet. The system’s centerpiece, the Central Solenoid, is a massive stack of superconducting magnets that stands 60 feet tall. Its final component was completed in April, and the entire system is poised for installation in France.

The Central Solenoid is no ordinary magnet; it generates a magnetic field around 280,000 times more powerful than Earth’s own, essential for controlling the plasma within the tokamak.

While the main reactor vessel is advancing, other crucial components are also being developed. On October 2, 2025, Mitsubishi Heavy Industries and Japan’s National Institutes for Quantum Science and Technology announced the successful completion of the first Outer Vertical Target (OVT) for the divertor. This mechanism functions as an exhaust system, efficiently removing impurities such as helium ash and unburnt fuel from the plasma to maintain a stable fusion reaction. The divertor must withstand peak heat loads of 20 megawatts per square meter, necessitating the use of specialized materials like tungsten, known for its high melting point.

A Global Collaboration Amid Challenges

ITER stands out from other nuclear fusion projects due to its unparalleled scale. While France’s WEST program achieved a world record for running a nuclear fusion reactor in February 2025, ITER plans to operate with five times the plasma volume of the largest current systems. This ambitious endeavor has faced numerous challenges since its inception, which dates back to 1985. Construction began in 2010, with the budget escalating from an initial $6 billion to over $20 billion.

Delays attributed to various factors, including the pandemic and difficulties in assembling international components, have pushed the timeline for deuterium-tritium operations to 2039. Despite these hurdles, ITER represents a historic collaboration involving 33 nations, including some geopolitical rivals, united in pursuit of a common goal: a sustainable energy future.

The ITER project not only signifies a monumental scientific endeavor but also aligns with the renewed focus on nuclear energy, reflecting its potential role in addressing global energy demands. As the project progresses, it stands as a testament to international cooperation and innovation in the quest for transformative energy solutions.