Fusion reactor tokamak

A tokamak is a ring-shaped nuclear fusion device that confines plasma at millions of degrees Celsius, aiming to replicate stellar energy on Earth.

About this subject

The tokamak is the leading experimental nuclear fusion reactor design, developed since the 1950s in the Soviet Union. Its name is a Russian acronym for "toroidal chamber with magnetic coils." The device uses powerful magnetic fields to confine plasma in a donut shape, preventing it from touching the reactor walls. The plasma, composed of hydrogen isotopes such as deuterium and tritium, is heated to over 150 million degrees Celsius to trigger nuclear fusion, releasing vast amounts of energy.

Currently, the largest international tokamak project is ITER, under construction in France, involving 35 countries. ITER will be the first reactor to produce more energy (500 MW) than required to heat the plasma, a milestone known as fusion gain. Other significant tokamaks include JET in the UK, which holds the fusion energy record, and KSTAR in South Korea. In Brazil, the ETE (Spherical Tokamak Experiment) operates at INPE since the 1990s, contributing to magnetic confinement research.

Fusion energy offers an almost limitless, safe, and carbon-free power source. Unlike fission, it produces no long-lived radioactive waste and has minimal accident risk. However, technical challenges remain, such as plasma stability and materials resistant to intense neutron flux. Recent advances, including AI for plasma control and high-temperature superconducting magnets, are speeding up the development of commercial reactors.

Interesting fact: the tokamak concept was originally secret in the USSR, but was revealed to the West in 1968 by Soviet scientist L. Artemovich. Since then, it has become the dominant fusion design. If successful, ITER will pave the way for DEMO, the first fusion reactor to generate electricity on the grid.

Frequently Asked Questions

How does a tokamak work?

A tokamak confines plasma in a ring shape using helical magnetic fields. The plasma is heated to extreme temperatures to fuse hydrogen nuclei, releasing energy as fast neutrons.

What is the difference between tokamak and stellarator?

Both magnetically confine plasma, but a tokamak uses an induced electric current in the plasma to generate part of the field, while a stellarator uses only external coils, making it more stable but harder to build.

When will we have commercial fusion energy?

Experts estimate the first commercial fusion plant (DEMO) could operate around 2050, following ITER results in the 2030s. Engineering and economic challenges remain.