Scientists and engineers at the ITER project in Cadarache, southern France, have completed the assembly of the reactor's central solenoid.

This milestone is critical because the central solenoid acts as the primary magnet used to create the plasma conditions necessary for nuclear fusion. By replicating the process that powers the Sun, the project aims to develop a source of nearly limitless clean energy.

The assembly represents a major technical step for the international effort to harness fusion. Unlike traditional nuclear fission, which splits atoms, fusion merges them to release energy without producing long-lived radioactive waste. The project seeks to prove that fusion can be maintained at a scale capable of powering electrical grids.

However, the project faces significant financial and competitive pressures. The cost of the ITER project to date has reached $22 billion [1]. This high expenditure has created a landscape where private fusion startups are attempting to reach similar milestones faster than the international consortium.

While ITER focuses on large-scale scientific validation, other nations are investing in alternative commercial paths. For example, Germany has provided €1.7 billion [2] in funding for a separate commercial fusion effort.

"ITER's central solenoid is finally assembled, but at $22 billion and counting, private fusion startups are already racing to beat it to its own milestones," a Yahoo News author said.

The completion of the solenoid allows the team to move closer to the first plasma experiments. These tests will determine if the magnetic confinement system can successfully stabilize the high-temperature plasma required for a net energy gain.

“The project aims to develop a source of nearly limitless clean energy.”

The assembly of the central solenoid signals that ITER is moving from the construction phase toward operational testing. While the technical achievement is significant, the massive $22 billion price tag underscores the tension between slow, large-scale international science and the agility of venture-backed private fusion firms. The outcome of ITER's upcoming plasma tests will likely determine if the 'big science' approach remains the primary path to commercial fusion or if smaller, private reactors will reach the grid first.