The International Nuclear and Radiological Event Scale (INES) was developed by the International Atomic Energy Agency (IAEA) and the Organisation for Economic Co-operation and Development (OECD) in 1990. Its purpose is to standardise the reporting of nuclear incidents or accidents with consistent international communication criteria and to enhance public understanding and awareness of the nature and significance of such incidents.

Public notification mechanism on non-
emergency LOEs at Daya Bay Nuclear Power Station and Ling Ao Nuclear Power Station

Under INES, nuclear events are classified from Level 0 to Level 7. Any event that happens in a nuclear power station that qualifies for the INES scale is considered as a Licensing Operational Event (LOE). All LOEs must be verified, reported, analysed and rectified to prevent any recurrence in the future. IAEA strongly encourages countries to communicate INES events of Level 2 or above to the international community within 24 hours if possible. The ultimate aim is to ensure appropriate and timely necessary action is taken.