The international community has created, under auspices of the International Atomic Energy Agency (IAEA), a system of notification and warning as well as a system of international assistance in case of a nuclear or radiological incident or accident. Rules governing these systems are fixed in two emergency conventions: the Convention on Early Notification of a Nuclear Accident and the Convention on Assistance in Case of a Nuclear Accident or Radiological Emergency. These conventions, which are primary legal instruments, establish an international framework to facilitate the exchange of information and the prompt provision of assistance in the event of a nuclear accident or radiological emergency. They have been signed by almost all EU Member States and IAEA member countries. Nevertheless, countries which have not signed these conventions still have a right to be informed and to ask for assistance if necessary. Within the framework of these conventions, the IAEA established an Incident and Emergency Centre (IEC) which operates 24 hours a day, seven days a week. The IEC facilitates the transfer of information, assistance of any kind, as well as procurement and transfer of material means if a country needs them. The emergency management arrangements cover not only incidents at nuclear power plants but also those involving the transport and disposal of radioactive materials.
Exchange of official information between countries and international organisations are facilitated by the IAEA's USIE system. This is an IAEA web portal for Contact Points of States Parties to the Convention of Early Notification of a Nuclear Accident and the Convention on Assistance in Case of a Nuclear Accident or Radiological Emergency and of IAEA Member States to exchange urgent information during nuclear and radiological incidents and emergencies and for officially nominated INES National Officers to post information on events rated using the International Nuclear and Radiological Event Scale (INES).
Incidents are classified following the International Nuclear Event Scale (INES)
in terms of their impact on three different areas: impact on people and the environment; impact on radiological barriers and controls at facilities; and defence in depth, which also covers events without any direct impact on people or the environment, but for which the range of measures put in place to prevent accidents did not function as intended. INES classifies incidents on a rising scale from 1 (a degradation of defence in depth with no impact on people or the environment) to 7 (a major accident with consequences for people, facilities or the environment).