International Nuclear and Radiological Event Scale (INES)
The INES Scale is an instrument used all over the world to give the public systematic information regarding the importance of nuclear and radiological events from the safety viewpoint.
The INES Scale indicates the importance of events that are the result of a wide range of activities
Just as it would be difficult to understand information on earthquakes or temperature without the Richter or Celsius scales, the INES Scale indicates the importance of events that are the result of a wide range of activities, including the industrial and medical use of radiation sources, the exploitation of nuclear sites and the transportation of radioactive materials.
Who developed the INES scale?
The International Atomic Energy Agency (IAEA) has co-ordinated the development of the scale in cooperation with the Nuclear Energy Agency (NEA/OCDE) and with the support of over 60 member States, via their national official INES authorities.
How is the classification done?
As regards this scale, events are sorted into seven levels. Level 1 to 3 events are known as “Incidents”, whereas level 4 to 7 events are described as “Accidents”. Each level increase in the scale indicates that the gravity of events is approximately ten times greater. When the events are not serious from the point of view of safety, they are called “Deviations” and classified “Below scale / Level 0”.
Each level increase in the scale indicates that the gravity of events is approximately ten times greater
How is the public informed?
The Member States that apply INES communicate nuclear and radiological events promptly. In situations where at first there is not enough information on all the details of an event, a provisional classification can be done followed later by the definitive classification, where any existing difference is explained.
In order to facilitate the international communication of events that are of greater interest, IAEA keeps a web-based communication network that grants the general public access to detailed information on the events.