India’s ‘artificial sun’: How close is fusion power to reality?

Amid India’s push for clean energy, the country has achieved a major milestone in its pursuit of nuclear fusion — a process often described as an “artificial sun”. If successfully harnessed, fusion technology could provide a limitless source of low-carbon energy and strengthen India’s position in the global energy landscape.

Unlike nuclear fission, which forms the basis of conventional nuclear power plants, nuclear fusion occurs when two light atomic nuclei combine to form a heavier nucleus, releasing a huge amount of energy in the process.

The reaction is similar to the one that powers the Sun and other stars.

A major advancement in India’s fusion research came early this month, when the Gujarat-based Institute for Plasma Research (IPR) installed a new 82.6 GHz, 400 kW gyrotron on the SST-1 tokamak. Sounds Greek? Let’s break it down.

Fusion takes place when nuclei collide with each other at extremely high temperatures, around ten million degrees celsius. At such temperatures, matter becomes plasma— an extremely hot, electrically charged gas made up of positively charged ions and free-moving electrons. 

Once the nuclei come within a very close range of each other, the attractive nuclear force between them will outweigh the electrical repulsion and allow them to fuse.

For this to happen, the nuclei must be confined within a small space to increase the chances of collision. In the sun and other stars, the extreme pressure produced by its immense gravity creates the conditions for fusion. 

Scientists are now developing technologies that can recreate some of these conditions in laboratories. 

SST-1, or Steady State Superconducting Tokamak, is an experimental fusion machine designed to recreate some of the extreme conditions required for nuclear fusion. 

A tokamak uses powerful magnetic fields to confine the extremely hot plasma inside a doughnut-shaped chamber, preventing it from coming into contact with surrounding walls and other materials.

A gyrotron is a high-power microwave device that heats the plasma to the extremely high temperatures needed for fusion research. The newly installed system at IPR operates at 82.6 GHz and can deliver 400 kW of power.

Why fusion technology is important

Fusion could generate about four times more energy per kilogram of fuel than fission and nearly four million times more energy than burning oil or coal. Although no fusion reactor currently operates as a commercial power plant, research and experiments in the field have gained momentum in recent years.

Most fusion reactor concepts use a mixture of deuterium and tritium — two isotopes of hydrogen that contain extra neutrons. According to the International Atomic Energy Agency (IAEA), fusion fuel is potentially abundant and widely accessible. Deuterium can be extracted relatively easily from seawater, while tritium could potentially be produced by using fusion-generated neutrons to react with lithium, which is naturally abundant.

Fusion also has important safety advantages. Unlike fission reactors, a fusion reaction cannot sustain itself without carefully controlled conditions. If those conditions are disrupted, the reaction quickly stops, meaning there is no risk of a runaway chain reaction or a conventional reactor meltdown. 

Fusion is also not expected to produce the same volume of long-lived, high-level radioactive waste associated with fission, although radioactive materials can still be generated through the activation of reactor components.