# A research team is investigating the long-term storage of radioactive waste produced by nuclear power stations. Some of the waste contains isotopes with very long half-lives, whilst other waste contains isotopes with very short half-lives. Explain why both types of waste present a hazard, and describe the difference between the hazards posed by radioactive contamination and irradiation.

> OCR A-Level Physics A (H556) — 6.3 Nuclear and particle physics · Explain · 5 marks

> Nuclear power stations produce radioactive waste that must be carefully managed. The waste is classified partly according to the half-lives of the isotopes it contains.

## Mark scheme (5 marks)

1. A long half-life isotope remains (weakly) radioactive for a long period of time, so presents a long-term hazard.
2. A short half-life isotope is initially highly/very radioactive, posing a large immediate hazard.
3. Radioactive contamination is the unwanted presence of radioactive atoms on or in a material/object.
4. Contamination is hazardous because the radioactive atoms continue to decay (emitting radiation) over time whilst present on the object.
5. Irradiation is exposure to nuclear radiation from an external source and only lasts whilst the object is near the source; the object does not become radioactive.

## Key terms

- [radioactive contamination](https://www.gradenine.co.uk/glossary/radioactive-contamination)
- [irradiation](https://www.gradenine.co.uk/glossary/irradiation)
- [isotope](https://www.gradenine.co.uk/glossary/isotope)

## Related

- [Revision notes for OCR A-Level Physics A (H556)](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/a-research-team-is-investigating-the-d1558b23) · Published by Druglandscape Ltd.