Fusion reactors are devices designed to replicate the process that powers the sun, where atomic nuclei combine to form a heavier nucleus, releasing a significant amount of energy. This process, known as nuclear fusion, has the potential to provide a nearly limitless source of clean energy, as it uses isotopes like deuterium and tritium found in water and lithium. Unlike traditional nuclear fission reactors, which split heavy atoms to release energy, fusion reactors produce minimal radioactive waste and carry a lower risk of catastrophic failure. Researchers are exploring various designs, such as tokamaks and stellarators, to achieve the high temperatures and pressures necessary for sustained fusion reactions.