International Nuclear and Radiological Event Scale (INES)
Scale used to classify the severity of nuclear incidents and accidents. It comprises 8 levels, from 0 to 7. Level 0 corresponds to an event of no safety significance; Level 7 is a major release of radioactive material with widespread health and environmental effects. Examples include the Chernobyl and Fukushima disasters. Levels 0 to 2 correspond to incidents with no impact outside the nuclear site.