Science
How does a nuclear reactor work?
A nuclear reactor works by splitting heavy atoms (nuclear fission) in a controlled chain reaction that releases enormous heat. That heat boils water into steam, which spins a turbine to generate electricity — essentially a giant, atom-powered kettle.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a nuclear reactor works.
Step by step
- 1A neutron strikes a uranium or plutonium nucleus, splitting it and releasing energy plus more neutrons.
- 2Those neutrons split more nuclei, sustaining a controlled chain reaction.
- 3Control rods absorb neutrons to speed up, slow down, or stop the reaction.
- 4The heat boils water; the resulting steam drives a turbine connected to a generator.
- 5It produces huge energy with no carbon emissions, but leaves radioactive waste.
Frequently asked questions
- Can a nuclear reactor explode like a bomb?
- No. Reactor fuel is far too low in fissile concentration to detonate like a bomb; the chain reaction is deliberately slow and controlled.
- What are control rods?
- Rods of neutron-absorbing material (like boron or cadmium) lowered into the core to soak up neutrons and throttle the reaction.
- What is nuclear waste?
- Used fuel and materials that stay radioactive for a long time and must be shielded and stored safely for thousands of years.