Nuclear Accidents 1 - International Nuclear and Radiological Event Scale.
The International Atomic Energy Agency (IAEA) introduced the International Nuclear and Radiological Event Scale (INRES ) in 1990 to categorized nuclear accidents to assist in communicating the seriousness and dangers of such events. The scale is logarithmic like the Richter scale for earthquakes. This means that each step up the scale in ten times the intensity of the prior step.