Nuclear reactors generate energy through a process known as nuclear fission, where the nucleus of an atom is split into two smaller fragments.

Nuclear fission serves as the fundamental mechanism that powers a nuclear reactor. This process typically involves the division of the nucleus of an atom, commonly uranium-235 or plutonium-239, into two smaller nuclei. The fission event releases a significant amount of energy, primarily in the form of heat. This heat is then utilized to produce steam, which drives a turbine connected to an electricity generator, thereby generating electrical energy.

The process initiates when a neutron is introduced into the nucleus of a uranium-235 or plutonium-239 atom. This interaction induces instability in the nucleus, causing it to split into two smaller nuclei, accompanied by the release of several free neutrons and a substantial amount of energy. These free neutrons can subsequently initiate further fission events, resulting in a self-sustaining chain reaction. In a nuclear reactor, this chain reaction is meticulously regulated to maintain a steady output of energy.

The heat generated from the fission process is absorbed by a coolant, typically water, which circulates around the reactor core. The heated water is then transformed into steam. This steam drives a turbine connected to an electricity generator, which converts the mechanical energy from the turbine into electrical energy, ready for distribution to the power grid.

Controlling the chain reaction is essential for the safe operation of a nuclear reactor. This is accomplished through the use of control rods, composed of materials that effectively absorb neutrons. By adjusting the position of these control rods, operators can manage the number of neutrons available to induce further fission reactions, thus regulating the rate of the chain reaction.

In summary, nuclear reactors produce energy by harnessing the process of nuclear fission. The energy released from the splitting of atomic nuclei is captured to generate steam, which drives a turbine to create electricity. This entire process is carefully controlled to ensure a steady and safe rate of energy production.