The world’s largest nuclear fusion reactor is finally complete, but it will be another 15 years before it’s operational, project scientists have announced.
The ITER fusion reactor, made up of 19 giant coils looped together around multiple magnet rings, was originally scheduled to begin its first full-scale tests in 2020. Scientists now say it could start up no earlier than 2039.
This is because fusion power generation, the cutting edge of which is the ITER tokamak, Solutions to the climate crisis.
“Certainly, the delay of ITER is not a step in the right direction,” ITER Director General Pietro Barabaschi said at a press conference on Wednesday (July 3). “Given the impact of fusion on the problems currently facing humanity, we should not wait for fusion to solve those problems. This would be unwise.”
The world’s largest nuclear reactor, the result of a collaboration between 35 countries including every member state of the European Union, Britain, China, India and the United States, contains the world’s most powerful magnets, capable of generating a magnetic field 280,000 times stronger than the Earth’s magnetic shield.
The reactor’s impressive design comes with an equally high price tag. Originally scheduled to cost around $5 billion and be operational in 2020, it has now been delayed multiple times, with a budget exceeding $22 billion, and an additional $5 billion proposed to cover additional costs. These unexpected expenses and delays are the cause of the last 15 years of delay.
Related: UK fusion reactor sets new world record for energy output
For more than 70 years, scientists have been trying to harness the power of nuclear fusion, the process that burns in stars. Main-sequence stars fuse hydrogen atoms under extreme pressure and temperature to create helium, converting matter into light and heat, producing vast amounts of energy without producing greenhouse gases or long-lasting radioactive waste.
But replicating the conditions found at the heart of a star is no easy task. Tokamak, the most common design of fusion reactor, works by superheating plasma (one of four states of matter consisting of positive ions and negatively charged free electrons) and confining it inside a doughnut-shaped reactor chamber with a strong magnetic field.
But keeping the coils of turbulent, superheated plasma in place long enough for fusion to occur has been a challenge. Soviet scientist Natan Yavlinsky designed the first tokamak in 1958, but since then no one has built a reactor that can output more energy than it takes in.
One of the main obstacles is dealing with plasma hot enough to cause nuclear fusion: Fusion reactors must operate at pressures much lower than those inside a star’s core, which necessitates extremely high temperatures (many times hotter than the Sun).
For example, the actual temperature at the core of the Sun reaches about 27 million degrees Fahrenheit (15 million Celsius), but the pressure is roughly 340 billion times the pressure at sea level on Earth.
Heating the plasma to this temperature is relatively easy, but finding a way to contain it so that it doesn’t burn up the reactor or interfere with the fusion reaction is technically more difficult – this is usually done using lasers or magnetic fields.