ITER ("The Way" in Latin) is one of the most ambitious energy projects in the world today.
In southern France, 35 nations are collaborating to build the world's largest tokamak, a magnetic fusion device that has been designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy based on the same principle that powers our Sun and stars.
The experimental campaign that will be carried out at ITER is crucial to advancing fusion science and preparing the way for the fusion power plants of tomorrow.
ITER will be the first fusion device to produce net energy
. ITER will be the first fusion device to maintain fusion for long periods of time. And ITER will be the first fusion device to test the integrated technologies, materials, and physics regimes necessary for the commercial production of fusion-based electricity.
Thousands of engineers and scientists have contributed to the design of ITER since the idea for an international joint experiment in fusion was first launched in 1985. The ITER Members—China, the European Union, India, Japan, Korea, Russia and the United States—are now engaged in a 35-year collaboration to build and operate the ITER experimental device, and together bring fusion to the point where a demonstration fusion reactor can be designed.
We invite you to explore the ITER website for more information on the science of ITER, the ITER international collaboration and the large-scale building project that is underway in Saint Paul-lez-Durance, southern France.
Fusion is the energy source of the Sun and stars. In the tremendous heat and gravity at the core of these stellar bodies, hydrogen nuclei collide, fuse into heavier helium atoms and release tremendous amounts of energy in the process.
Twentieth-century fusion science identified the most efficient fusion reaction in the laboratory setting to be the reaction between two hydrogen isotopes, deuterium (D) and tritium (T). The DT fusion reaction produces the highest energy gain at the "lowest" temperatures.
Three conditions must be fulfilled to achieve fusion in a laboratory: very high temperature (on the order of 150,000,000° Celsius); sufficient plasma particle density (to increase the likelihood that collisions do occur); and sufficient confinement time (to hold the plasma, which has a propensity to expand, within a defined volume).
At extreme temperatures, electrons are separated from nuclei and a gas becomes a plasma—often referred to as the fourth state of matter. Fusion plasmas provide the environment in which light elements can fuse and yield energy.
In a tokamak device, powerful magnetic fields are used to confine and control the plasma.
ITER's First Plasma is scheduled for December 2025.
That will be the first time the machine is powered on, and the first act of ITER's multi-decade operational program.
On a cleared, 42-hectare site in the south of France, building has been underway since 2010. The ground support structure and the seismic foundations of the ITER Tokamak are in place and work is underway on the Tokamak Complex—a suite of three buildings that will house the fusion experiments. Auxiliary plant buildings such as the ITER cryoplant, the radio frequency heating building, and facilities for cooling water, power conversion, and power supply are under construction.
As soon as access to the Tokamak Building is possible, scientists and engineers will progressively assemble, integrate, and test the ITER fusion device. Commissioning will ensue to verify that all systems function together and to prepare the ITER machine for operation.
The successful integration and assembly of over one million components (ten million parts), built in the ITER Members' factories around the world and delivered to the ITER site constitutes a tremendous logistics and engineering challenge. The assembly workforce, both at ITER and in the Domestic Agencies, will reach 2,000 people at the height of assembly activities. In the ITER offices around the world, the exact sequence of assembly events has been carefully orchestrated and coordinated. The first large components were delivered to the ITER site in 2015.
In November 2017, the project passed the halfway mark to First Plasma. (More here
Decision to site the project in France
Signature of the ITER Agreement
Formal creation of the ITER Organization
Land clearing and levelling
Ground support structure and seismic foundations
for the Tokamak
Nuclear licensing milestone: ITER becomes a Basic Nuclear Installation under French law
Construction of the Tokamak Building (access for assembly activities in 2019)
Construction of the ITER plant and auxiliary buildings for First Plasma
Manufacturing of principal First Plasma components
Largest components are transported along the ITER Itinerary
Assembly phase I
Integrated commissioning phase (commissioning by system starts several years earlier)
Deuterium-Tritium Operation begins
Throughout the ITER construction phase, the Council will closely monitor the performance of the ITER Organization and the Domestic Agencies through a series of high-level project milestones.
See the Building ITER
page for more information on ITER construction and assembly. See Milestones
for incremental milestones on the way to First Plasma.