Radiation Safety
Section: Nuclear Physics | Syllabus: Cambridge IGCSE Physics (0625)
Effects of Ionising Nuclear Radiation on Living Things
Ionising nuclear radiation can have harmful effects on living things, including:
| Effect | Description |
|---|---|
| Cell death | High doses of radiation can damage vital cell structures and DNA badly enough to kill cells |
| Mutations | Radiation can damage DNA, causing changes (mutations) that may be passed on when a cell divides |
| Cancer | Radiation damage to the genes that control cell division can cause uncontrolled cell growth, forming a tumour |
Safe Handling of Radioactive Materials
Radioactive materials must be moved, used and stored in a safe way.
- Moving: handle sources with long-handled tongs, never directly with the hands, and transport them in shielded (e.g. lead-lined) containers
- Using: never point a source at a person, keep it at arm's length or further, use shielding where possible, and work as quickly as is safely possible to minimise exposure time
- Storing: keep sources in lead-lined containers in a secure, clearly labelled location when not in use
Radioactive sources should be handled with tongs and stored in shielded containers
Explaining Safety Precautions
Extended Only
Safety precautions for all types of ionising radiation can be explained in terms of three factors: reducing exposure time, increasing distance between the source and living tissue, and using shielding to absorb radiation.
- Reducing exposure time: the radiation dose received is proportional to the time spent near a source, so working quickly and planning tasks carefully reduces the dose
- Increasing distance: radiation intensity decreases with distance from the source, so using long-handled tongs or remote-handling equipment, or simply standing further away, reduces the dose
- Using shielding: placing an absorbing material between the source and living tissue prevents radiation from reaching the body; the material needed depends on the type of radiation being shielded against
| Radiation Type | Shielding Required |
|---|---|
| Alpha (α) | A sheet of paper is enough to absorb it |
| Beta (β) | A few millimetres of aluminium |
| Gamma (γ) | Several centimetres of lead, or a thick layer of concrete |
The shielding material needed depends on the type of radiation
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