In the hills of southern France, far from daily political drama and market headlines, a single engineering move is quietly reshaping what “possible” looks like for nuclear fusion. At the ITER site near Cadarache, teams have installed vacuum chamber module #5—one of the massive steel sectors that will form the sealed, doughnut-shaped vessel where superheated plasma is meant to be confined and controlled.
The placement of module #5 is not just another construction update. It signals that the tokamak’s main ring is taking physical shape, with three of the nine vacuum vessel modules now sitting in the tokamak pit.
Why module #5 is a big deal for ITER
ITER is building a tokamak—a device designed to trap plasma with magnetic fields long enough to study sustained fusion conditions. At the center of that system is the vacuum vessel, a toroidal chamber assembled from nine huge modules that must align with extreme precision.
With module #5 now in position alongside modules #7 and #6, the project reaches a visible milestone: one-third of the vacuum vessel modules have been installed in their final location.
What the vacuum vessel modules actually contain
A vacuum vessel module is not simply curved steel. Each sector integrates key elements needed for fusion operations and for protecting superconducting systems around it. According to the project details, the modules incorporate components such as superconducting magnet coils, shielding, and interfaces for systems that will later heat, fuel and diagnose the plasma.
ITER’s design targets plasma temperatures of around 150 million degrees, meaning the internal surfaces and surrounding structures must be engineered to handle extreme thermal and mechanical conditions.
How engineers install a module measured in hundreds of tonnes
Installing module #5 required days of tightly controlled handling, where the challenge is not just lifting weight—it’s placing it within tiny tolerances. Even small deviations can create misalignments that complicate later welding and sealing of the full torus.
From cleaning to precision positioning
Before entering the tokamak pit, the module passes through a dedicated cleaning process in an air-filtered building to reduce contamination risk inside the vacuum system. Once cleared, it is moved into the assembly area and lifted using overhead cranes in coordinated operations.
During positioning, metrology systems such as laser tracking continuously verify alignment against reference points so teams can compensate for deformation, crane deflection and thermal expansion as the module is tilted and lowered.
A global supply chain behind a single machine
ITER’s scale forces international industrial collaboration, with different firms responsible for different integration tasks. The article notes that the CNPE consortium—bringing together Chinese entities with France’s Framatome—handles major work around magnet-related integration and module installation. Italy’s SIMIC S.p.A. is involved in positioning and interconnection work inside the vacuum chamber, while India’s Larsen & Toubro focuses on ultra-precise welding for parts of the chamber that will later host diagnostics and access ports.
Once all nine modules are installed, Westinghouse (United States) is expected to carry out final welding to turn the segmented structure into a continuous torus.
What comes next: six modules still to install
With modules #7, #6 and now #5 installed, ITER’s remaining vacuum vessel sectors (#1–4 and #8–9) are still pending. The stated target is to complete installation of the remaining modules in 2026, operating roughly on a cadence of one sector every two to three months.
After the ring is closed, work shifts toward final welds, leak checks and the staged integration of internal systems such as the divertor and diagnostic equipment that will be essential for managing plasma performance and materials stress.
Timeline pressures and the long road to first plasma
ITER has experienced repeated schedule changes since construction began in 2010. Early expectations for first plasma around 2025 were pushed back, with current plans described in the article pointing to subsystem commissioning around 2028–2029 and a first hydrogen plasma around 2030. Deuterium-tritium operations—expected to demonstrate high fusion output relative to input heating—are projected for the 2035–2039 timeframe.
The article also cites an estimated budget exceeding €22 billion, funded across Europe, China, India, Japan, South Korea, Russia and the United States—underscoring how the project’s pace is shaped not only by physics and manufacturing, but by long-term political and financial commitment.
Context: why ITER still matters as private fusion accelerates
ITER’s progress is unfolding alongside a broader fusion race that includes national programs and private ventures, particularly those exploring new magnet technologies and compact reactor approaches. Even so, ITER remains a central reference point for validating large-scale tokamak engineering, materials behavior and operational models—data that many fusion efforts rely on to reduce risk.
Keys
- ITER has installed vacuum chamber module #5, bringing the total to three modules in the tokamak pit (#7, #6 and #5).
- The vacuum vessel is assembled from nine modules that must be aligned to extremely tight tolerances.
- Module installation involves multi-day crane operations, cleaning procedures and continuous metrology tracking.
- Multiple international firms contribute, including CNPE/Framatome, SIMIC S.p.A., Larsen & Toubro and Westinghouse for final welding.
- Remaining modules are targeted for installation in 2026, while first hydrogen plasma is planned around 2030.
