The element used in the production of nuclear energy is uranium. Specifically, uranium-235 (U-235) is the isotope that undergoes fission in nuclear reactors, releasing immense amounts of energy. In nuclear power plants, uranium is typically formed into fuel rods and placed in a reactor core. When the nucleus of U-235 is struck by a neutron, it splits into lighter elements, releasing energy in the form of heat. This heat is then used to produce steam, which drives turbines to generate electricity. Uranium is mined and processed to create fuel suitable for both civilian power generation and military applications.