# Explain why nuclear fusion has not yet been used as a commercial source of energy, despite being capable of releasing large amounts of energy.

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

> Scientists have been researching nuclear fusion as a potential energy source for several decades. In fusion, two small, light nuclei join to form a larger, heavier one and release energy.

## Mark scheme (4 marks)

1. Fusion requires extremely high temperatures to occur
2. High temperatures are needed so that the nuclei have enough energy / speed to overcome the electrostatic repulsion between them
3. It is very difficult / expensive to contain a plasma or material at such high temperatures
4. More energy is currently needed to sustain the reaction than the reaction releases / engineers have not yet achieved a sustained net energy output

## Key terms

- [nuclear fusion](https://www.gradenine.co.uk/glossary/nuclear-fusion)

## Related

- [Revision notes for AQA GCSE Physics (8463)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-nuclear-fusion-has-not-86cd8e9a) · Published by Druglandscape Ltd.