Fusion reactor tokamak

The tokamak is a magnetic confinement device designed to enable controlled nuclear fusion, replicating on Earth processes that occur in the Sun's core.

About this subject

A tokamak is a nuclear fusion reactor that uses intense magnetic fields to confine plasma at temperatures exceeding 150 million degrees Celsius, a condition necessary for light atomic nuclei, such as deuterium and tritium, to fuse and release energy. The concept was developed in the 1950s by Soviet physicists Igor Tamm and Andrei Sakharov, and the first operational device was built at the Kurchatov Institute in Moscow. The name "tokamak" is a Russian acronym for "toroidal chamber with magnetic coils."

The main advantage of the tokamak over other fusion designs is its ability to maintain stable plasma for longer periods, thanks to the combination of a toroidal magnetic field (around the main axis) and a poloidal field (generated by an electric current within the plasma itself). This configuration creates a helical structure that prevents plasma particles from escaping. Currently, the largest experiment in this line is ITER, under construction in France, which aims to demonstrate the commercial viability of fusion.

Nuclear fusion in tokamaks offers a potentially unlimited energy source, with abundant fuel (deuterium extracted from seawater and tritium produced from lithium), no greenhouse gas emissions, and low-level radioactive waste. However, enormous technical challenges remain, such as material degradation from intense neutron radiation and plasma instabilities. Recent advances, including the use of high-temperature superconductors in coils, are bringing fusion closer to commercial reality, with projects like SPARC (USA) and JT-60SA (Japan) contributing to research.

Frequently Asked Questions

How does a tokamak work?

A tokamak confines superheated plasma in a donut shape using magnetic fields. The plasma is heated to extreme temperatures so that atomic nuclei overcome electrostatic repulsion and fuse, releasing energy.

What is the difference between fusion and nuclear fission?

In fusion, light nuclei combine to form a heavier nucleus, releasing energy. In fission, heavy nuclei split. Fusion produces less long-lived radioactive waste and has no risk of uncontrolled chain reaction.

Will ITER produce commercial energy?

ITER is an experiment to prove that fusion can produce more energy than it consumes. If successful, the next generation of reactors (like DEMO) could generate electricity for the grid.