Nuclear Energy 1. Atoms are the particles that make up all objects in the universe.
Atoms consist of neutrons, protons, and electrons.
In nuclear fusion, energy is released when the nuclei of atoms are combined or fused together. This is how the sun produces energy. In nuclear fission, energy is released when the nuclei of atoms are split apart. Nuclear fission is the only method currently used by nuclear plants to generate electricity. The fuel most widely used by nuclear power plants for fissioning is uranium.