# Explain what happens inside a nuclear reactor to produce energy, including how the chain reaction is controlled.

> WJEC A-Level Physics (Wales) — 3.6 Nuclear energy · Explain · 5 marks

> Nuclear power stations generate electricity using energy released from the nuclei of uranium atoms.

## Mark scheme (5 marks)

1. Uranium nucleus absorbs a neutron / is struck by a neutron
2. The nucleus undergoes fission / splits into two smaller nuclei (daughter nuclei)
3. More neutrons are released which can go on to cause further fissions / trigger a chain reaction
4. Control rods absorb neutrons to control the rate of fission / chain reaction
5. Energy released (from fission) is used to heat water / produce steam to drive a turbine / generate electricity

## Key terms

- [chain reaction](https://www.gradenine.co.uk/glossary/chain-reaction)

## Related

- [Revision notes for WJEC A-Level Physics (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-what-happens-inside-a-nuclear-694f3651) · Published by Druglandscape Ltd.