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What is nuclear energy?

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Quick answer

Nuclear energy is the energy released when atomic nuclei are split (fission) or fused (fusion). Power plants use controlled fission of uranium to boil water, spin turbines, and generate electricity with almost no carbon emissions. Fission splits heavy atoms (uranium); fusion joins light atoms (and powers the Sun).

Key things to understand

  1. Fission splits heavy atoms (uranium); fusion joins light atoms (and powers the Sun).
  2. Reactors use the heat released to make steam that drives turbines.
  3. It produces large, steady, low-carbon electricity.
  4. Downsides: radioactive waste and the need for strict safety.

People also ask

What's the difference between fission and fusion?
Fission splits heavy atoms; fusion combines light ones. Today's plants use fission; fusion is still experimental.
Is nuclear energy clean?
It emits almost no carbon, but it produces long-lived radioactive waste that must be carefully stored.
Is nuclear power safe?
Modern reactors have strong safety systems; serious accidents are rare but high-consequence, so it's tightly regulated.

Part of the guide: Energy & Electricity at Home →