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How does a nuclear reactor work?

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Quick answer

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. A neutron strikes a uranium or plutonium nucleus, splitting it and releasing energy plus more neutrons.

Step by step

  1. A neutron strikes a uranium or plutonium nucleus, splitting it and releasing energy plus more neutrons.
  2. Those neutrons split more nuclei, sustaining a controlled chain reaction.
  3. Control rods absorb neutrons to speed up, slow down, or stop the reaction.
  4. The heat boils water; the resulting steam drives a turbine connected to a generator.
  5. It produces huge energy with no carbon emissions, but leaves radioactive waste.

People also ask

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.
How does a nuclear reactor make electricity?
Fission heat boils water into steam, which spins a turbine connected to a generator.
What do control rods do?
They absorb neutrons to slow or speed the chain reaction, keeping it controlled and safe.

Part of the guide: Energy & Electricity at Home →