Preparedness and Response to a Nuclear or Radiological Emergency

1. What is radioactivity?

Atoms are made of a nucleus, composed of a number of protons and neutrons, and of electrons that form a cloud around it. The number of protons in an atom determines its elemental identity and for the same element there can be different numbers of neutrons, which each form a different isotope, or nuclide. Some of these nuclides (like the isotope¹⁴ carbon or all uranium isotopes) are unstable, and spontaneously will reajust their internal structure towards a more stable form.

Radioactivity is defined as the spontaneous emission of particles (alpha, beta, neutron) or radiation (gamma, K capture), or both at the same time, from the decay of certain unstable nuclides due to an adjustment of their internal structure¹. Radioactivity can be natural or artificial. In natural radioactivity, the substance has this potential in the natural state whereas artificial radioactivity is induced by irradiation of the substance.

Radiation and radioactive substances have many beneficial applications, ranging from power generation to uses in medicine, industry and agriculture. Each of these applications have their own specific needs and requirements for safety and security. The radiation risks to workers, the public, and the environment, that may arise from these applications have to be assessed and, if necessary, controlled.

¹ https://nuclear-energy.net/definitions/radioactivity.html 

2. What is the IAEA and what does it do?

The IAEA (International Atomic Energy Agency) is the international body responsible for developing safety standards and technical tools. It provides capacity building to support its Member States in strengthening their emergency arrangements in coordination with agencies of the United Nations. Organizations responsible for the management of emergencies recognize indeed that good preparedness can substantially improve the adequateness of their responses. One of the most important elements of such emergency preparedness is the coordination of arrangements among the different bodies involved to ensure clear lines of responsibility and authority.

Information on the IAEA’s safety standards programme is available on http://www-ns.iaea.org/standards/ .

Such standards nevertheless are only effective if they are properly applied in practice and regulating safety is a national responsibility and many States have decided to adopt the IAEA’s standards for use in their national regulations.

This publication is the new edition establishing an integrated and consistent set of safety requirements for preparedness and response for a nuclear or radiological emergency irrespective of its cause and considers the latest experience and developments in the area².

² Safety related terms are to be understood as defined in the IAEA Safety Glossary (see http://www-ns.iaea.org/standards/safety-glossary.htm ). Otherwise, words are used with the spellings and meanings assigned to them in the latest edition of The Concise Oxford Dictionary. For Safety Guides, the English version of the text is the authoritative version.

3. To whom and what do these safety requirements apply?

The safety requirements are recommended for use by Member States and by national authorities in relation to their own activities. However, these are binding in relation to the operations of the IAEA itself and to the operations that its Member States (169 countries of the 193 that member of the United Nations) undertake with the IAEA.

Based on potential hazards assessments, the requirements apply for preparedness and responses in case of a crisis o accident:

• For a nuclear or radiological emergency in relation to all the facilities and activities warranting protective actions and other response actions; 
• In relation to off-site jurisdictions that may need to take protective actions and other response actions;  
• For preparedness and response for a nuclear or radiological emergency no matter the cause of the emergency, whether the emergency follows a natural event, a human error, a mechanical or other failure, or a nuclear security event. 

The hazard assessments include consideration of various types of events that could affect the facility or activity, including events of very low probability. The IAEA requirements, however, do not cover preparedness for, or response measures that are specific to criminal or intentional unauthorized acts that involve nuclear or radioactive materials (what is referred to as a ‘nuclear security event’). There are specific recommendations that are provided in other IAEA documents that cover these, but the radiological consequences of these events do fall within the scope of these requirements.

4. What are the goals of an emergency response?

The development of a protection strategy should include, but not be limited to, actions to be taken to avoid or to minimize severe deterministic effects (those for which a direct dose-effect link is known such as radiation sickness) and to reduce the risk of stochastic effects (those whereby the probability of their occurrence, but not their severity, is a function of the dose without the existence of a threshold value, such as a cancer), the setting of a reference exposure level expressed in terms of residual dose and national generic criteria for taking protective actions and other response actions expressed in terms of projected dose or of dose that has been received.

In a nuclear or radiological emergency, the goals of the emergency response(s) are thus:

1. To regain control of the situation and to mitigate consequences;
2. To save lives;
3. To avoid or to minimize severe deterministic effects;
4. To render first aid, to provide critical medical treatment and to manage the treatment of radiation injuries;
5. To reduce the risk of stochastic effects;
6. To keep the public informed and to maintain public trust;
7. To mitigate, to the extent practicable, non-radiological consequences;
8. To protect, to the extent practicable, property and the environment;
9. To prepare, to the extent practicable, for the resumption of normal social and economic activity.

5. What are the main requirements expected from governments of a nuclear or radiological emergency preparedness management system?

To ensure that appropriate requirements are met, the governments have to establish a national coordinating mechanism to be functional at the preparedness stage. This mechanism should be coherent with the emergency management system, which, among other duties, will coordinate and ensure consistency between the emergency arrangements of the various response organizations, operating organizations and the regulatory body at local, regional and national levels under the all-hazards approach.

The main requirements are that:

1. Hazard assessment is performed to provide a basis for a graded preventive approach in preparedness and response;
2. Protection strategies are developed, justified and optimized;  
3. An integrated and coordinated emergency management system is established and maintained; 
4. Relevant international organizations coordinate their arrangements in preparedness and their emergency response actions;

Preparedness is a key and functionally, any government has to ensure that arrangements are in place for:

1. response operations to be appropriately managed,
2. the rapid identification and notification of an emergency,
3. the taking of mitigatory and protective actions,  
4. providing the public with the information necessary for their protection,
5. protecting emergency workers and for appropriate medical action.

Clearly establishing plans, authorities, training, and logistics is also the responsibility of governments, and they have to arrange for waste management, protective actions and international assistance.

Minimum arrangements should also be taken for the protection of emergency workers and protection of helpers in an emergency for the range of anticipated hazardous conditions in which they might have to perform response functions.

More details are given at the Level 2 of these Highlights.