How a nuclear reactor makes electricity
At heart, a nuclear power plant is a way to boil water. What makes it different is where the heat comes from.
Fission: splitting atoms for heat
Reactor fuel is usually uranium formed into ceramic pellets and sealed in metal rods. When a uranium-235 atom absorbs a neutron, it can split (fission), releasing a large amount of energy as heat plus more neutrons. Those neutrons split more atoms, creating a controlled chain reaction.
Keeping it under control
- Control rods absorb neutrons; moving them in or out slows or speeds the reaction.
- A moderator (in most reactors, ordinary water) slows neutrons down so they’re more likely to cause fission.
- Coolant carries heat away from the fuel.
From heat to the grid
The heat makes steam, the steam spins a turbine, and the turbine drives a generator — the same final steps a coal or gas plant uses, without burning fuel or emitting carbon dioxide while running.
Coming next
Small modular reactors (SMRs), how spent fuel is stored, and how nuclear’s safety record compares with other sources.