Fusion reactor tokamak

A tokamak is an experimental nuclear fusion device that confines plasma in toroidal magnetic fields, aiming to generate clean and abundant energy.

About this subject

The tokamak is the most advanced type of nuclear fusion reactor, a technology that aims to replicate on Earth the process that powers the Sun. Its name comes from the Russian acronym for 'toroidal chamber with magnetic coils', and the first prototype was built in the Soviet Union in the 1950s. The principle is to confine extremely hot plasma (above 150 million degrees Celsius) within a donut-shaped magnetic field, preventing the material from touching the reactor walls.

Currently, the largest tokamak project under construction is ITER in France, an international collaboration involving 35 countries. ITER aims to demonstrate the commercial viability of fusion, producing 500 MW of power from just 50 MW of input. Other important tokamaks include JET in the UK, which holds the record for fusion energy generated (16 MW in 1997), and KSTAR in South Korea, which achieved plasmas of 100 million degrees for over 20 seconds.

Nuclear fusion offers significant advantages over fission: virtually unlimited fuel (deuterium from seawater and tritium bred from lithium), no risk of meltdown, and short-lived radioactive waste. However, the technical challenge is immense: maintaining stable plasma for long periods and developing materials that withstand neutron bombardment. Scientists at MIT and Commonwealth Fusion Systems are testing high-temperature superconducting magnets, which could reduce reactor size and cost.

In the Brazilian context, the country participates in ITER through technological and scientific contributions. The National Fusion Laboratory (LNF) in São Paulo operates the TCABR tokamak, focusing on turbulence and confinement studies. Although fusion is still decades away from commercial deployment, recent advances in superconductors and artificial intelligence for plasma control are accelerating development.

Frequently Asked Questions

How does a tokamak work?

A tokamak heats hydrogen to a plasma state and uses powerful electromagnets to confine it in a toroidal chamber. The plasma reaches temperatures above 150 million degrees, allowing deuterium and tritium nuclei to fuse, releasing energy.

What is the difference between fusion and fission?

Fission splits heavy atoms (like uranium), producing long-lived radioactive waste and posing meltdown risks. Fusion joins light atoms (hydrogen isotopes), yielding abundant energy with short-lived waste and no meltdown danger.

When will nuclear fusion be commercially available?

Experts estimate the first commercial fusion reactors could operate between 2040 and 2060. Projects like ITER and SPARC (Commonwealth Fusion Systems) are accelerating the timeline, but significant technical challenges remain.