Hollywood has paid an indirect tribute to how fusion power has the potential to transform our world by using the technology to spice up movie scripts.

In Iron Man, the heroā€™s protective suit is powered by fusion.

Before he turns bad, ā€˜s Doctor Octopus creates a new power source using fusion.

, starring Keanu Reeves and Rachel Weisz, hinges on the invention of a rival fusion technology to that used by ITER (so-called bubble fusion).

In , Val Kilmer attempts to steal a fusion formula from Elisabeth Shue. Once again, Hollywood scriptwriters have opted for a highly speculative alternative to ITER.

The Mr. Fusion Home Energy Reactor was the name of a power source used by the DeLorean time machine that starred in the movie trilogy.

Fusion reactors turn up in Star Trek too, for instance to power the impulse engines on Federation starships.

Read more: ITER: The way to a benign and limitless new energy source

Some 70 years ago scientists obtained the first insights into the physics of sunshine: when the sun and other stars transmute matter, tirelessly transforming hydrogen into helium by the process of fusion, they release colossal amounts of energy.

By the mid-1950s ā€œfusion machinesā€ were operating in the Soviet Union, the United Kingdom, the United States, France, Germany and Japan. Yet harnessing the energy of the stars was to prove a formidable task.

After pioneering work in the Soviet Union in the late 1950s, a doughnut-shaped device called a tokamak was to become the dominant concept in fusion research. Since then, tokamaks have passed several milestones.

Experiments with actual fusion fuel ā€“ a mix of the hydrogen isotopes deuterium and tritium ā€“ began in the early 1990s in the Tokamak Fusion Test Reactor (TFTR) in Princeton, US, and the Joint European Torus (JET) in Culham, UK. JET marked a key step in international collaboration, and in 1991 achieved the worldā€™s first controlled release of fusion power.

While a significant amount of fusion power was produced by JET, and TFTR, exceptionally long-duration fusion was achieved in the Tore Supra tokamak, a EURATOM-CEA installation located at Franceā€™s Cadarache nuclear research centre and later in the TRIAM-1M tokamak in Japan and other fusion machines.

In Japan, JT-60 has achieved the highest values of the three key parameters on which fusion depends ā€“ density, temperature and confinement time. Meanwhile, US fusion installations have reached temperatures of several hundred million Ā°C.

In JET, TFTR and JT-60 scientists have approached the long-sought ā€œbreak-even pointā€, where a device releases as much energy as is required to produce fusion. ITERā€™s objective is to go much further and release 10 times as much energy as it will use to initiate the fusion reaction. For 50 MW of input power, ITER will generate 500 MW of output power.

ITER will pave the way for the Demonstration power plant, or DEMO, in the 2030s. As research continues in other fusion installations worldwide, DEMO will put fusion power into the grid by the middle of this century. The last quarter of this century will see the dawn of the Age of Fusion.

Read more: ITER: The way to a benign and limitless new energy source

Itā€™s simple ā€“ in principle, at least. Take two forms (isotopes) of hydrogen, squash them together, and you get a helium atom and a very energetic subatomic particle called a neutron.

The product of the reaction is a fraction lighter than its atomic ingredients, and by Einsteinā€™s famous equation E = mc² that tiny loss of mass results in a colossal release of energy. Harness that release in an efficient way and the worldā€™s energy needs are solved.

The problem is that the atomic ingredients of fusion, like all nuclei, repel each other.

In the core of the sun, huge gravitational pressure allows fusion to take place at temperatures of around 15 million Ā°C. In fusion machines, temperatures to achieve fusion need to be much higher ā€“ above 150 million Ā°C.

No materials on Earth could withstand direct contact with such temperatures. To achieve fusion, therefore, ITER will use a device called a tokamak, which holds the reacting plasma away from the furnaceā€™s walls with intense magnetic fields.

The aim is for ITER to generate 500 megawatts of fusion power. This would pave the way for a demonstration power plant, called DEMO, in which fusion power will produce steam and ā€“ by way of turbines ā€“ up to 1000 megawatts of net electrical power. Thatā€™s equivalent to a power plant that could supply about half a million British homes.

Fuelled by water

The most efficient fusion reaction is that between two forms (isotopes) of hydrogen: deuterium and tritium.

While deuterium can be extracted from seawater in virtually boundless quantities, the worldwide supply of tritium is limited, estimated at only 20 kilograms.

Future fusion power plants will have to produce their own tritium. They will use ā€œtritium breeding modulesā€ made from lithium, which turns into tritium when bombarded by neutrons from the fusion reaction. Lithium is a light metal, as abundant as lead.

ITER will test experimental tritium breeding modules.

Catch a star

How can ITER handle matter 10 times as hot as the core of the sun? By trapping it inside a strong magnetic field.

Magnetic fusion machines of various shapes and arrangements were developed in several countries as early as 1950. But the breakthrough occurred in 1968 in the Soviet Union, when researchers were for the first time able to achieve remarkably high temperature levels and plasma confinement time ā€“ two key criteria for fusion.

The secret of their success was a revolutionary doughnut-shaped magnetic confinement device called a tokamak, developed at the Kurchatov Institute, Moscow.

From this time on, the tokamak became the dominant concept in fusion research.

Environmental impact

The terrific heat generated by fusion will be absorbed using 3 million cubic metres of water per year, about a fifth of the total transported by the local Verdon river.

Tritium releases are predicted to be 100 times lower than the regulatory limit.

Fusion reactions produce no long-lived waste. Low-level radioactive waste will result from the activation of some of the machineā€™s components. All waste materials will be treated, packaged and stored on site.

In all, 39 protected or rare species will benefit from measures on the 180-hectare ITER site. Two areas have been fenced off to protect the Occitan cricket, two species of butterfly, woodlark nesting sites and rare orchids.

Of the 2.5 million cubic metres of earth and rock moved to level the ITER platform, over two-thirds were reused on site.

Read more: ITER: The way to a benign and limitless new energy source