To mitigate potential damage that could arise from unwanted situations, every nuclear facility incorporates in its organization a number of emer­gency provisions, which are laid down on the assumption that the safety systems are not sufficient to control such extraordinary situations. Strictly speaking, the emergency arrangements are not part of the design of the facility, although they provide an additional guarantee of protection from the risk associated with nuclear facilities.

These arrangements should be set out in a specific emergency plan that reflects the likelihood and the possible consequences of nuclear accidents, the characteristics of the radiation risks and the nature and location of the facilities. These emergency plans are designed and prepared to ensure that arrangements are in place for a timely, managed, controlled, coordinated and effective response at the scene, and at the local, regional, national and international level, to any nuclear or radiological emergency. The emer­gency plans are usually structured in two levels: on-site emergency plans and off-site emergency plans.

The on-site emergency plans are direct targets to lead the facility that has suffered an accident to safe conditions as soon as possible, to minimize potential consequences of the accident on the staff and the installation, and to reduce the release of radioactive material to the environment. The on-site emergency plan is a primary responsibility of the plant operator and is a part of the safety documentation needed for obtaining the operating licence of every facility. The plant operator is also responsible for maintaining on-site emergency plans in an operational state by checking their effective­ness before the facility becomes operational and whilst the facility is in operation by performing suitable emergency exercises.

The off-site emergency plans are aimed at the preparation and, where appropriate, implementation of the emergency measures necessary to protect the population living around a nuclear facility against any damage caused by any accident occurring at the facility. The public authorities are responsible for designing and implementing the off-site emergency plans as a part of the national response plans established for protecting the popula­tion from any unwanted situation that could damage their health, their property or the environment. Off-site plans have to be established before every facility becomes operational and their effectiveness should be checked during the pre-operation testing period and periodically whilst the facility is in operation. Off-site emergency plans include suitable international interfaces when trans-boundary consequences of accidents that could occur in a facility are possible.