ITER (International Thermonuclear Experimental Reactor) by ITER Organization: status and timeline

Milestones

Next · Research operations phase (hydrogen and deuterium plasma)

5th vacuum vessel sector installed in tokamak pitMay 2026Complete.
6th vacuum vessel sector installedJul 2026Complete.
Two-thirds of tokamak core installed (six of nine sectors)Jul 2026Complete.
All core tokamak components on siteOct 2026Complete.
Research operations phase (hydrogen and deuterium plasma)Target 2034Not yet reached.
Deuterium-deuterium fusion operationTarget 2035Not yet reached.
Deuterium-tritium operationsTarget 2039Not yet reached.

Upcoming

2034Research operations phase (hydrogen and deuterium plasma) (next)
2035Deuterium-deuterium fusion operation
2039Deuterium-tritium operations

Current obstacles

Plasma instabilities at scaleLarger tokamaks develop new instability modes; control requires advances in real-time diagnostics and feedback.
Plasma-wall interactionsHeat and particle fluxes to the first wall are orders of magnitude higher than in smaller tokamaks.

Physics limits

Tokamak Q has a theoretical limitThe ratio of fusion power output to heating power input (Q) is fundamentally limited by plasma confinement physics; Q > 10 requires excellent confinement and high pressure.
Neutron activation of structuresFast neutrons from fusion damage reactor materials, becoming radioactive over time and limiting component lifespans.

How it works

3 parts

Magnetic confinement

Plasma held by strong magnetic fields

Superconducting coils create toroidal and poloidal magnetic fields that confine plasma hotter than the Sun's core.

Heating

Microwaves and particle beams

The plasma is heated by neutral beam injection and radiofrequency heating to over 150 million degrees Celsius.

Fusion reaction

Deuterium and tritium nuclei fuse

In D-T fusion, the nuclei merge and release neutrons and helium, with each reaction releasing 17.6 MeV of energy.

Spec sheet

Spec	ITER (International Thermonuclear Experimental Reactor)
Vacuum vessel height	11.4 m^R (reported)
Total mass	23,000 tonnes^R (reported)
Major radius	6.2 m^R (reported)
Plasma volume	840 m³^R (reported)

^R reported by the company

About ITER Organization

The team behind ITER (International Thermonuclear Experimental Reactor)

ITER Organization

ITER tokamak, international fusion, Cadarache France

ITER is the world's reference tokamak fusion research facility, operated by an international organization representing 34 countries and multiple regions. Under construction in Cadarache, southern France, ITER will be the largest tokamak ever built.

ITER's multinational consortium of 34 countries targets D-D operation in 2035, D-T fusion by 2039.
Core assembly is halfway complete as of October 2026; all major components are on site.
The project is the world's largest and most complex tokamak, built at Cadarache in southern France.

iter.org (opens iter.org)Company profile →

Founded: 200719 yrs
Headquarters: France
Status: Public
Valuation: public
Works in: EnergyFusion
Coverage: 1 program · 3 updateslatest 9d agochecked 10 Oct
Partners: European Union (opens iter.org)China (opens iter.org)India (opens iter.org)Japan (opens iter.org)Russian Federation (opens iter.org)South Korea (opens iter.org)United States (opens iter.org)

Spec

ITER (International Thermonuclear Experimental Reactor)

Vacuum vessel height

11.4 m^R (reported)

Total mass

23,000 tonnes^R (reported)

Major radius

6.2 m^R (reported)

Plasma volume

840 m³^R (reported)