While an emergency involving nuclear material is generally rare, having the necessary preparedness is essential should such an event occur. Being well-prepared will control the emergency’s development, mitigate its outcome, and protect people and the environment against the uncontrolled release of radioactive substances particularly from a nuclear power plant.

In the case of a nuclear power plant, emergency preparedness is generally provided for the plant with an “on-site emergency plan” which enables the deployment of human and technical resources at the plant. The plan, to be supported by corporate emergency measures of its owner utility, serves to facilitate corporate decisionmaking, activate various technical centres of the owner utility to support the plant operating team in controlling the plant situation and to protect staff at the plant site. There is also an “off-site emergency plan” outside the plant at the regional and national level of the government. This directs regional and national resources to provide further technical support plus bring in administrative and logistical resources for public protection and communication.

The on-site emergency plan defines the organisation and resources to handle the emergency at the plant site. It typically identifies the needed site response according to the nature and severity of an emergency at the plant, initiated either by an internal or external hazard. In contrast, the off-site emergency plan focuses on the intensity and duration of radiological impact to the public and the environment. Furthermore the provision of resources and countermeasures are designed to keep radiation exposure to the public within acceptable criteria.

The severity of an emergency at a plant is classified by the extent of its impact into four levels, as promulgated by the International Atomic Energy Agency. The lowest level “alert” requires taking actions to assess and mitigate the potential consequences of an event and to raise organisational readiness. The next three levels follow in increasing severity, classified as “facility emergency”, “site area emergency” and “general emergency”. Each level requires protective and response actions both on-site and off-site to mitigate consequences of the event and to protect people.

This article is contributed by Ir Richard Fung with the coordination of the Nuclear Division.