The amount of fusion energy a tokamak is capable of producing correlates directly to the number of fusion reactions taking place in its core. Scientists know that the larger the vessel, the larger the volume of the plasma ... and therefore the greater the potential for fusion energy.
With ten times the plasma volume of the largest machine operating today, the ITER Tokamak will be a unique experimental tool, capable of longer plasmas and better confinement. The machine has been designed specifically to:
1) Produce 500 MW of fusion power for pulses of 400 s
The world record for controlled fusion power is held by the European tokamak JET. In 1997, JET produced 16 MW of fusion power from 24 MW of heating power injected into the fusion plasma (Q=0.67). ITER is designed for much higher fusion power gain (Q
) or Q ≥ 10. For 50 MW of injected heating power it will produce 500 MW of fusion power for long pulses of 400 to 600 seconds. ITER will not capture the power it produces as electricity, but as the first of all fusion experiments in history to produce net energy
... it will prepare the way for the machine that can.
2) Demonstrate the integrated operation of technologies for a fusion power plant
ITER will bridge the gap between today's smaller-scale experimental fusion devices and the demonstration fusion power plants of the future. Scientists will be able to study plasmas under conditions similar to those expected in a future power plant and test technologies such as heating, control, diagnostics, cryogenics and remote maintenance in an integrated way.
3) Achieve a deuterium-tritium plasma in which the reaction is sustained through internal heating
Fusion research today is at the threshold of exploring a burning plasma. In a burning plasma, the energy of the helium nuclei produced when hydrogen isotopes fuse becomes large enough—because of the large number of reactions—to exceed the plasma heating that is injected from external sources. As the first such burning plasma device in the world, ITER will offer scientists a unique opportunity to chart new territory in controlled nuclear fusion.
4) Test tritium breeding
One of the missions for the later stages of ITER operation is to demonstrate the feasibility of producing tritium within the vacuum vessel. The world supply of tritium (used with deuterium to fuel the fusion reaction) is not sufficient to cover the needs of future power plants. ITER will provide a unique opportunity to test mockup in-vessel tritium breeding
blankets in a real fusion environment.
5) Demonstrate the safety characteristics of a fusion device
In 2012, when the ITER Organization obtained licensing as a nuclear operator in France, the ITER fusion device became the first in the world to have successfully undergone the rigorous examination of its safety case. One of the primary goals of ITER operation is to demonstrate control of the plasma and fusion reactions with negligible consequences to the environment.
ITER is designed to produce a ten times return on invested energy: 500 MW of fusion power from 50 MW of input heating power (Q=10). It will be the first of all fusion experiments in history to produce net energy.
The construction of the ITER scientific installation in St-Paul-lez-Durance, France, has been underway since 2010. In parallel, the ITER Members have been procuring the components and systems of the ITER machine and plant. Equipment has been arriving on site since 2015 and in 2020, the ITER Organization officially launched machine assembly.
The first ITER assembly phase, which includes the assembly of the core machine as well as the installation of all plant systems needed for First Plasma, will be followed by a commissioning phase to ensure all systems operate together. Commissioning will end with the achievement of First Plasma in December 2025*.
Staged operation—that is, periods of scientific experimentation alternating with periods of further assembly to bring the machine to its full power configuration—is planned from 2025 to 2035. ITER's operational phase is expected to last for 20 years: first, a several-year "shakedown" period of operation in pure hydrogen is planned during which the machine will remain accessible for repairs and the most promising physics regimes will be tested. This phase will be followed by operation in deuterium with a small amount of tritium to test wall-shielding provisions. Finally, scientists will launch a third phase with increasingly frequent operation with an equal mixture of deuterium and tritium, at full fusion power.
*Component manufacturing and transport has been affected by the 2020-2021 Covid-19 pandemic. The ITER Organization is currently assessing all effects on the schedule and possible mitigation measures and will report to the ITER Council in June 2022. ITER's detailed Research Plan can be downloaded from the Technical Reports page.
- Fusion world | JET makes history, again
- Science | New steady state analysis
- ITER Research Plan | The 400-page scenario
- Plasma-surface interactions | Where two worlds meet
- Plant systems | Entering the stage, one by one
- Plasma physics | The Tao of Q
- Operational phase | Experts of the world, unite!
- Thinking ahead to decommissioning
- The fellowship of fusion science
- They are building the physics basis for ITER
- "Code camp": sitting around the virtual plasma