A nuclear reactor is a complex system that generates electricity through controlled nuclear fission. The main components include fuel rods containing uranium, control rods to regulate the reaction rate, a moderator to slow down neutrons, and coolant to transfer the heat produced by fission.
Nuclear fission is the process that powers the reactor. When a neutron strikes a uranium two three five atom, it becomes unstable and splits into two smaller fragments. This releases enormous amounts of energy as heat, plus two to three new neutrons that can strike other uranium atoms, creating a self-sustaining chain reaction.
The chain reaction must be carefully controlled to maintain safe operation. Control rods made of neutron-absorbing materials like boron or cadmium can be inserted deeper into the core to slow the reaction, or withdrawn to speed it up. The moderator, usually water, slows down the fast neutrons produced by fission, making them more likely to cause additional fission events.
The heat generated by fission must be converted to electricity. Hot coolant from the reactor core flows to a steam generator, where it heats water to create high-pressure steam. This steam drives a turbine connected to an electrical generator. The turbine's rotation generates electricity, while the steam is condensed back to water and returned to the system.
To summarize how a nuclear reactor works: Nuclear fission in fuel rods generates heat through a controlled chain reaction. Control rods and moderators regulate this process safely. The heat converts water to steam, which drives turbines connected to generators, producing clean electricity for our communities.