All nuclear power stations have emergency plans in the event of a disaster. In the case of a ‘general emergency’ – one in which radiation cannot be contained within the site and threatens to contaminate the surrounding area, different ‘emergency planning zones’, depending on the level of risk, are recognised. These are as follows:
- 5km radius of the source: people in this area would be at highest risk for radiation exposure.
- 16km radius of the source: people could potentially be harmed by direct radiation exposure.
- 80km radius of the source: radioactive materials may contaminate water supplies, crops and livestock
The above zones are, of course, only a model of most likely risk. There are multiple factors that affect the severity of a general emergency - the nature of the accident, the size of the radiation 'cloud', prevailing wind direction, rainfall and topography.
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Take a look at the map below to see the danger zones around Koeberg nuclear power station just outside Cape Town. The orange circles indicate affected areas of a Koeberg meltdown {KAA,2012} . Image: Deannorman