# A nuclear power station uses uranium-235 as fuel. Describe what happens during a chain reaction in the reactor core, including the role of the neutrons released.

> AQA GCSE Physics (8463) — 4.4.4 Nuclear fission and fusion (Phys only) · Describe · 4 marks

> Nuclear fission of uranium-235 is used in power stations to generate electricity. The fission reaction releases energy along with several neutrons.

## Mark scheme (4 marks)

1. A neutron is absorbed by a uranium-235 nucleus, causing it to split (undergo fission)
2. The fission produces two smaller (more stable) nuclei / fission products
3. Two or three neutrons are released during the fission
4. The released neutrons are absorbed by other uranium nuclei, causing further fission reactions / the process repeats / self-sustaining reaction

## Key terms

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

## Related

- [Revision notes for AQA GCSE Physics (8463)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-nuclear-power-station-uses-uranium-235-1ffc66d3) · Published by Druglandscape Ltd.