ITER
ITER (International Thermonuclear Experimental Reactor) is the world’s largest international science project, designed to demonstrate the scientific and technological feasibility of fusion power. Located in Saint-Paul-les-Durance, southern France, ITER represents a crucial step toward practical fusion energy.
Mission and Objectives
Section titled “Mission and Objectives”ITER’s primary goal is to demonstrate that fusion can produce more energy than it consumes. Specifically, it aims to:
- Achieve Q = 10 (produce 500 MW of fusion power from 50 MW of heating power)
- Sustain fusion power for 400-600 seconds
- Demonstrate integrated operation of technologies for a fusion power plant
- Test tritium breeding concepts
- Validate safety characteristics of fusion devices
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value |
|---|---|
| Plasma major radius | 6.2 m |
| Plasma minor radius | 2.0 m |
| Plasma volume | 840 m3 |
| Plasma current | 15 MA |
| Magnetic field (on axis) | 5.3 T |
| Fusion power | 500 MW |
| Pulse duration | 400-600 s (inductive), up to 3600 s (non-inductive) |
| Total weight | 23,000 tonnes |
Member Parties and Contributions
Section titled “Member Parties and Contributions”Seven parties participate in ITER, representing 35 countries:
| Party | Contribution (approximate) |
|---|---|
| European Union | 45% (host party) |
| Japan | 9% |
| United States | 9% |
| Russia | 9% |
| China | 9% |
| South Korea | 9% |
| India | 9% |
Each party contributes “in-kind” by manufacturing specific components rather than providing cash. This approach allows each member to develop their domestic fusion industry.
Japan’s Contributions
Section titled “Japan’s Contributions”Japan is responsible for several critical components:
- Toroidal field coil conductors (partially)
- Central solenoid conductors
- Neutral beam injection heating system
- Blanket remote handling system
- Divertor (outer target)
Japan also hosts the Broader Approach activities, including JT-60SA and IFMIF-DONES.
Construction Progress
Section titled “Construction Progress”Major Milestones
Section titled “Major Milestones”- 2007: ITER Organization established
- 2010: Ground-breaking ceremony
- 2013: First building completed
- 2020: Machine assembly begins
- 2025: First magnet installation completed
- 2035: First plasma (revised target)
- 2035-2040: Deuterium-tritium operation
Current Status
Section titled “Current Status”As of 2025, significant progress has been made:
- Tokamak building construction completed
- Superconducting magnets being installed
- First cryostat sector installed
- Vacuum vessel sectors under assembly
The project has faced delays and cost increases, but assembly work continues at the construction site.
Key Technologies
Section titled “Key Technologies”Superconducting Magnets
Section titled “Superconducting Magnets”ITER uses the world’s largest superconducting magnet system:
- 18 Toroidal Field (TF) coils using Nb3Sn conductor, cooled to 4.5 K
- 6 Poloidal Field (PF) coils using NbTi conductor
- Central Solenoid: 13 m tall, 4.2 m diameter, providing 13 T
Heating Systems
Section titled “Heating Systems”Three main heating methods will bring plasma to 150 million degrees Celsius:
- Neutral Beam Injection (NBI): 33 MW
- Ion Cyclotron Resonance Heating (ICRH): 20 MW
- Electron Cyclotron Resonance Heating (ECRH): 20 MW
Blanket and Divertor
Section titled “Blanket and Divertor”- First wall and blanket modules protect the vacuum vessel and will test tritium breeding
- Divertor: Handles 10 MW/m2 heat flux using tungsten tiles
Technical Challenges
Section titled “Technical Challenges”Plasma Stability
Section titled “Plasma Stability”Maintaining stable plasma at 150 million degrees for hundreds of seconds requires sophisticated control systems to prevent:
- Edge Localized Modes (ELMs)
- Disruptions
- Resistive wall modes
Materials
Section titled “Materials”Components must withstand extreme conditions:
- Intense neutron bombardment (14 MeV neutrons)
- High heat loads
- Strong electromagnetic forces
Tritium Handling
Section titled “Tritium Handling”ITER will use significant quantities of tritium, requiring:
- Safe handling and containment systems
- Tritium breeding blanket modules for testing
- Environmental protection measures
Beyond ITER: The Path to DEMO
Section titled “Beyond ITER: The Path to DEMO”ITER is designed as an experimental reactor, not a power plant. Following ITER’s success, demonstration power plants (DEMO) will generate electricity. ITER’s research will provide essential data for:
- Plasma control in power-plant-relevant conditions
- Materials performance under neutron irradiation
- Tritium breeding and handling at scale
- Integrated system operation
Significance
Section titled “Significance”ITER represents humanity’s most ambitious attempt to harness fusion energy. Its success would demonstrate that fusion power is achievable, paving the way for commercial fusion power plants in the second half of this century.