7.2.5: The Promise of Fusion

Fusion Power

The Sun produces energy through nuclear fusion, a process that joins small atomic nuclei together to form larger nuclei. On Earth, scientists are working to recreate this process by heating hydrogen isotopes to extremely high temperatures, creating a superheated state of matter called plasma. When atomic nuclei collide with enough energy, they can fuse and release large amounts of energy. A common fusion reaction combines deuterium and tritium, two forms of hydrogen, to produce helium and energy (figure \(\PageIndex{a}\)).  Although fusion power plants do not yet generate electricity commercially, researchers continue to study this technology because of its potential to provide a low-carbon energy source.

Although no commercial fusion power plants are operating today, fusion energy could offer several important benefits if scientists and engineers succeed in producing electricity from this process. Fusion reactions are controlled by powerful magnetic fields, so if the power supply is interrupted, the reaction stops almost immediately. As a result, fusion reactors cannot experience the type of runaway meltdown associated with some nuclear fission reactors. Fusion is also expected to produce far less long-lived radioactive waste than current nuclear technologies. Because its fuel can be derived from hydrogen isotopes found in water, fusion has the potential to provide a reliable, low-carbon source of energy with a strong safety profile.

Scientists and engineers are actively working to make fusion energy a viable source of electricity. In San Diego, the DIII-D National Fusion Facility has been studying fusion technology for many years. One of the most ambitious international projects is ITER, a large experimental fusion reactor being built in southern France through collaboration among many nations. ITER is designed to test technologies needed for future fusion power plants. These systems typically use a doughnut-shaped chamber called a tokamak, where strong magnetic fields hold and control superheated plasma so that fusion reactions can occur (figure \(\PageIndex{b}\)).