Préparation et réponses à une urgence nucléaire ou radiologique

1. Introduction

Organizations responsible for the management of emergencies (including conventional emergencies) recognize that good preparedness of any emergency can substantially improve the response. One of the most important elements of emergency preparedness is the coordination of arrangements among the different bodies involved to ensure clear lines of responsibility and authority.

The statutory objective of IAEA established in 1957 is to seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world. One of the IAEA’s statutory functions is “to establish or adopt, in consultation and, where appropriate, in collaboration with the competent organs of the United Nations and with the specialized agencies concerned, standards of safety (including such standards for labour conditions), and to provide for the application of these standards”.

Deriving from this function, the IAEA develops safety standards and technical tools, supports its Member States in strengthening their emergency arrangements, provides for capacity building in its Member States, and performs, at the request of Member States, peer reviews on established emergency arrangements.

2. What is the aim of this IAEA publication?

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 area. Safety measures and security measures have in common the aim of protecting human life and health and protecting the environment, both now and in the future. The requirements are governed by the objective and principles of the Safety Fundamentals.

These Safety Requirements are intended to be used by governments, emergency response organizations, other authorities at the local, regional and national levels, operating organizations and the regulatory body, as well as by relevant international organizations at the international level.

It expands on, complements and organizes the requirements relating to emergency management established in Safety Series No. 115, International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources².

² More Information on the IAEA’s safety standards programme is available on http://www-ns.iaea.org/standards/ 

3. Who should apply these safety requirements for preparedness and response for a nuclear or radiological emergency?

Regulating safety is a national responsibility; these requirements are recommended for use by Member States and by national authorities in relation to their own activities and are to be applied by the Sponsoring Organizations³ to their own operations in line with their respective mandates. Those Sponsoring Organizations are committed to continuously improving emergency preparedness and to coordinating response to a nuclear or radiological emergency in line with these safety requirements, their respective mandates and, as appropriate, the Joint Radiation Emergency Management Plan of the International Organizations.

States that are members of Sponsoring Organizations other than the IAEA may adopt these safety requirements, at their discretion, or in accordance with their membership obligations, for application to their own activities. All international organizations, irrespective of whether or not they are members of the Inter-Agency Committee on Radiological and Nuclear Emergencies (IACRNE), are also encouraged to consider these safety requirements in establishing or enhancing their own emergency arrangements.

Globally, many states have decided to adopt the IAEA’s standards for use in their national regulations. Anyway, these safety requirements are binding on the IAEA Secretariat in relation to its own operations and on Member States in relation to operations assisted by the IAEA.

³ The Sponsoring Organizations include 13 international organizations: the FAO, the IAEA, the International Civil Aviation Organization (ICAO), the ILO, the International Maritime Organization (IMO), INTERPOL, the OECD/NEA, PAHO, the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), the United Nations Environment Programme (UNEP), OCHA, the WHO and the World Meteorological Organization (WMO).

3. 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 ¹⁴Carbon isotope and 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 nuclides due to an adjustment of their internal structure⁴.

Radioactivity can be natural or artificial. In natural radioactivity, the substance already has this potential in the natural state whereas artificial radioactivity is induced by irradiation. In nature there are about 300 different nuclides, from which 25 are radioactive with a very long period; 35 others have a much shorter period. Continuously they are created and they decay into radioactive series.

Radiation and radioactive substances have many beneficial applications, ranging from power generation to uses in medicine, industry and agriculture. The radiation risks to workers and the public and to the environment that may arise from these applications have to be assessed and, if necessary, controlled.

⁴ https://nuclear-energy.net/definitions/radioactivity.html 

5. What is taken into consideration in a nuclear hazard assessment?

The hazard assessment includes consideration of various types of events that could affect the facility or activity, including events of very low probability or not considered in the design:

• Events involving a combination of a nuclear or radiological emergency with a conventional emergency such as an emergency following an earthquake, a volcanic eruption, a tropical cyclone, severe weather, a tsunami, an aircraft crash or civil disturbances that could affect wide areas and/or could impair capabilities to provide support in the emergency response;
• Events that could affect several facilities and activities concurrently, as well as consideration of the interactions between the facilities and activities affected;
• Events at facilities in other States or events involving activities in other States.

In the hazard assessment, account is taken of uncertainties and of limitations of the information available, to warrant any of the following early protective response actions:

1. Precautionary urgent actions to avoid or to minimize severe deterministic effects by keeping doses below levels approaching the generic criteria at which urgent protective actions and other response actions are required to be undertaken under any circumstances; 
2. Urgent actions and other response actions to avoid or to minimize severe deterministic effects and to reduce the risk of stochastic effects;  
3. Other emergency response actions such as longer term medical action and actions aimed at enabling the termination of the emergency; 
4. Protection of emergency workers in accordance with requirements. 

Protection of emergency workers in accordance with requirements.

6. The safety requirements for a nuclear or radiological emergency apply to what, more specifically?

This publication provides the interpretation and entry into force of the requirements, the goals of emergency preparedness and response, the general requirements that are to be met before effective emergency arrangements can be made, defines by using a graded approach the emergency preparedness categories for which the requirements have been established and elaborates on the development of a protection strategy on the basis of the hazards assessed.

Other sections establish the requirements to be met for performing the functions critical for an effective emergency response and requirements for the infrastructure necessary to develop and maintain adequate arrangements for preparedness.

Appendices provide guidance values for restricting exposure of emergency workers in a nuclear or radiological emergency and generic criteria for use in emergency preparedness and response.

The safety requirements established by the IAEA do provide for a coordinated and integrated approach to preparedness and response for an emergency arising from a nuclear security event⁵ that necessitates protective actions and other response actions to be taken for protection of members of the public, workers and emergency workers, helpers in an emergency and patients.

These requirements apply:

1. For a nuclear or radiological emergency in relation to all those facilities and activities, as well as sources, with the potential for causing radiation exposure, environmental contamination or concern on the part of the public warranting protective actions and other response actions; 
2. In relation to off-site jurisdictions that may need to take protective actions and other response actions;  
3. For preparedness and response for a nuclear or radiological emergency irrespective of the initiator of the emergency, whether the emergency follows a natural event, a human error, a mechanical or other failure, or a nuclear security event.

The requirements, however, do not cover preparedness or response measures that are specific to nuclear security events for which recommendations include activities for the identification, collection, packaging and transport of elements contaminated with radionuclides, nuclear forensics or related actions in the context of investigation about the circumstances surrounding these events.

⁵ A‘nuclear security event’ is an event that has potential or actual implications for nuclear security that must be addressed. Such events include criminal or intentional unauthorized acts involving or directed at nuclear material, other radioactive material, associated facilities or associated activities. A nuclear security event, for example, sabotage of a nuclear facility or detonation of a radiological dispersal device, may give rise to a nuclear or radiological emergency.

7. What is included in a protection strategy?

The development of a protection strategy should include, but not be limited to, the following:

1. Actions to be taken to avoid or to minimize severe deterministic effects a(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, seuch as cancer ), evaluated on the basis of relative biological effectiveness (RBE) weighted absorbed dose to a tissue or organ;  
2. The setting of a reference exposure level expressed in terms of residual dose typically as an effective dose in the range 20–100 milliSiverts or mSv), acute or annual, that includes dose contributions via all exposure pathways. This reference level shall be used in conjunction with the goals of emergency response and the specific time frame in which particular goals are to be achieved. 
3. National generic criteria for taking protective actions and other response actions, expressed in terms of projected dose or of dose that has been received. If the national generic criteria for projected dose or received dose are exceeded, protective actions and other response actions, either individually or in combination, have to be implemented; 
4. Pre-established operational criteria (conditions on the site, emergency action levels and operational intervention levels) for initiating the different parts of an emergency plan and for taking protective actions and other response actions shall be derived once the protection strategy has been justified and optimized, and a set of national generic criteria has been developed.  

Arrangements have to be established in advance to make possible to revise as appropriate in the course of a nuclear or radiological emergency the operational criteria with account taken of the prevailing conditions as they evolve.

8. What are the goals of an emergency response in case of a nuclear or radiological emergency?

The 9 main goals of a response in case of a nuclear or radiological emergency are:

1. To regain control of the situation and to mitigate consequences; 
2. To save lives; 
3. To avoid or to minimize severe deterministic effects 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 non-radiological consequences to the extent practicable; 
8. To protect property and the environment to the extent practicable; 
9. To prepare for the resumption of normal social and economic activity, to the extent practicable. 

Relevant international organizations have then to coordinate their arrangements in preparedness for a nuclear or radiological emergency and their emergency response actions.

9. What should be more specifically prepared to promptly notify a nuclear or radiological emergency?

For taking appropriate protective actions and other response actions effectively, promptly upon notification of a nuclear or radiological emergency, arrangements shall include:

1. Prompt exercise of authority and discharge of responsibility for making decisions to initiate protective actions and other response actions upon notification of an emergency; 
2. Warning the permanent population, transient population groups and special population groups or those responsible for them, and warning special facilities; 
3. Taking urgent protective actions and other response actions such as evacuation, restrictions on the food chain and on water supply, prevention of inadvertent ingestion, restrictions on the consumption of food, milk and drinking water and on the use of commodities, decontamination of evacuees, control of access and traffic restrictions; 
4. Protection of emergency workers and helpers in an emergency. 

In the communication to the various stakeholders about the emergency, account should be taken of the possibility that the usual means of communication might be damaged in the emergency or by its initiating event (e.g. by an earthquake or by flooding) or overburdened by demand for its use.

The information has to be provided to the public in plain and understandable language and the arrangements shall also include arrangements for keeping the international community informed, as appropriate and take also into account the need to protect sensitive information in circumstances where a nuclear or radiological emergency is initiated by a nuclear security event.

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

The main requirements from a government are that it ensures that an integrated and coordinated emergency management system for preparedness and response for a nuclear or radiological emergency is established and maintained. To this end, a hazard assessment has to be performed to provide a basis for a graded approach, and protection strategies have to be developed, justified and optimized at the preparedness stage for taking protective actions and other response actions.

Arrangements shall include emergency operating procedures and guidance for operating personnel on mitigatory actions for severe conditions (for a nuclear power plant, as part of the accident management programme), and for the full range of postulated emergencies, including accidents that are not considered in the design and associated conditions.

As far as practicable, the continued functionality of nuclear security system(s) needs to be considered. The operating personnel directing actions to mitigate the consequences of the emergency shall be provided with information and technical assistance to allow them to take actions effectively. Arrangements shall also be made such that information on emergency conditions, assessments and protective actions and other response actions that have been taken is promptly made available to all relevant response organizations and to the IAEA throughout the emergency.

Further arrangements shall be made for actions to save human life or to prevent serious injury to be taken without any delay on the grounds of the possible presence of radioactive material. Off-site emergency planning zones and emergency planning distances will be specified for which arrangements shall be made at the preparedness stage for taking protective actions and other response actions effectively.

11. What are the functional arrangements to be put in place to manage a response to a nuclear or radiological emergency?

Functionally, any government has to ensure that arrangements are in place and appropriately managed for the operations in response to a nuclear or radiological emergency including:

Preparedness:

• Establish clearly authorities, all roles and responsibilities for preparedness and response, specifying an overall organization staffed with sufficient personnel who are qualified and assessed for their fitness for their intended duties;
• Ensure that these means are clearly allocated in advance among operating organizations, the regulatory body, and response organizations. This shall include a system for classifying all types of nuclear or radiological emergency;
• Ensure that necessary plans and procedures are established for effective response; in particular arrangements will be foreseen to:
  1. Notify all persons on the site of an emergency;
  2. Take appropriate actions immediately upon notification of an emergency for all persons on the site;
  3. Account for those persons and to locate and recover those unaccounted for;
  4. Provide immediate first aid and take urgent protective actions with suitable escape routes, assembly points and continuous radiation monitoring;
  5. Provide suitable and reliable alarm systems and other means for warning and instructing all persons present under the full range of emergency conditions. 
• Ensure that personnel relevant for emergency response shall take part in regular training, drills and exercises to ensure that they are able to effectively perform their assigned response functions;  
• Ensure that a programme is established within an integrated management system to ensure the availability and reliability of all supplies, equipment, adequate logistical support and facilities communication systems and facilities, plans, procedures and other arrangements necessary for effective response in a nuclear or radiological emergency; 
• Periodically review and update emergency plans and procedures. 

Emergency response:

• Identify and notify promptly of a nuclear or radiological emergency, and for the activation of an emergency; 
• Assess emergency conditions taking urgent protective and mitigatory actions and other response actions effectively;  
• Warn promptly the public who are affected or are potentially affected providing them with information that is necessary for their protection and instruct them on actions to be taken; then communicating with the public throughout the emergency;  
• Protect emergency workers and helpers and ensure an appropriate medical screening and triage, medical treatment and longer term medical actions such as providing registration, health screening and longer term medical follow-up, as appropriate; 
• Take early protective actions and other response actions effectively such as an effective relocation that may be required and for the prevention of inadvertent ingestion; 
• Integrate the provision of existing assistance for preparedness and response between the operating organization and authorities at the local, regional and national levels, and, where appropriate, at the international level;  
• Take actions to mitigate non-radiological consequences; 
• Assess the effectiveness of the actions taken and adjusting them as appropriate on the basis of prevailing conditions and available information as well as the reference level expressed in terms of residual dose; 
• Promptly notify the IAEA of the emergency in the event of a transnational emergency and, either directly or through the IAEA, those States that could be affected by it. 

Post–emergency:

• Ensure that radioactive waste is managed safely and effectively and mitigate the non-radiological consequences, with account taken of the need for the resumption of social and economic activity;  
• Analyse afterwards the emergency response in order to identify actions to be taken to avoid other emergencies and to improve emergency arrangements, and revising the protection strategy as necessary as well as its further implementation;  
• Discontinue protective actions and other response actions when they are no longer justified. 

12. What has to be specifically foreseen to protect the emergency workers and helpers?

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, the minimum arrangements should include:

1. Training those emergency workers designated as such in advance, and providing emergency workers not designated in advance and helpers in an emergency immediately before the conduct of their specified duties, with instructions on how to perform the duties under emergency conditions (‘just in time’ training); and obtaining informed consent to perform specified duties, when appropriate; 
2. Provision of appropriate specialized protective equipment and monitoring equipment and managing, controlling and recording the doses received including provision of iodine thyroid blocking, if exposure due to radioactive iodine is possible; 
3. Providing medical examination, longer term medical actions and psychologic counselling, as appropriate. 

In particular, the operating organization and response organizations shall ensure that emergency workers who undertake emergency response actions in which doses received might exceed an effective dose of 50 mSv do so voluntarily; have been clearly and comprehensively informed in advance of associated health risks as well as of available protective measures and that they are trained in the actions that they might be required to take.

13. What are the main preparedness initiatives to develop to meet these requirements?

The appropriate responsible authorities shall ensure that a ‘concept of operations’ for emergency response is developed at the beginning of the preparedness stage, and that emergency plans and procedures are prepared and approved for any facility or activity, area or location that could give rise to an emergency warranting protective actions and other response actions. Response organizations and operating organizations, as appropriate, have to be involved in the preparation of emergency plans and procedures, and account will be taken in the content, features and extent of emergency plans of the results of any hazard assessment and any lessons from operating experience and from past emergencies, including conventional emergencies.

For the purposes of these safety requirements, hazards shall be identified and potential consequences of an emergency shall be assessed to provide a basis for establishing arrangements for preparedness with the aim of allowing for the prompt initiation of an effective response. Assessed hazards are grouped in accordance with the emergency preparedness categories and response for a nuclear or radiological emergency. The categories include different types of facilities (classified in categories I to IV), including nuclear power plants, research reactors, nuclear reactors used to provide power for the propulsion of vessels (e.g. ships and submarines) and industrial irradiation facilities or some hospitals activities.

The preparedness initiatives will also ensure that operating organizations, response organizations and the regulatory body establish, maintain and demonstrate leadership in relation to preparedness and response.

For facilities and locations for which there is a significant likelihood of encountering a dangerous source that is not under control and for an emergency at an unforeseen location, arrangements shall be made to ensure that the local officials responsible for the response and first responders are aware of the indicators of a potential radiological emergency, the appropriate notification, and protective actions and other response actions that are warranted to be taken immediately in an emergency.

It shall also be ensured that the transition to the emergency response and the performance of initial response actions do not impair the ability of operating personnel (such as operating personnel in a control room) to ensure safe and secure operation while taking mitigatory actions. One or more off-site notification point will have to be established to receive notification of an actual or potential nuclear or radiological emergency.

14. What are the main functions to be assigned for managing a nuclear emergency?

Emergency response facilities or locations to support an emergency response under the full range of postulated hazardous conditions shall be designated and they shall operate as an integrated system in support of the response to avoid conflicting with one another’s functions.

The main following functions will be assigned, as appropriate to provide reasonable assurance of being operable and habitable under a range of postulated hazardous conditions:

1. Receiving notifications and initiating the response and coordination and direction of on-site response actions;
2. Providing technical and operational support to those personnel performing tasks at a facility and direction of off-site response actions, and coordination with on-site response actions of personnel responding off the site;
3. Coordination of national response actions and of communication with the public;
4. Managing those people who have been evacuated (including reception, registration, monitoring and decontamination, as well as provision for meeting their personal needs, including for housing, food and sanitation), and providing individuals who have undergone exposure or contamination with appropriate medical attention including medical treatment. 
5. Coordination of monitoring, sampling and analysis and managing the storage of necessary resources; 

15. When can the decision to terminate the nuclear or radiological emergency and to transition to an existing exposure situation be taken ?

The decision to terminate the nuclear or radiological emergency and the subsequent transition to an existing exposure situation is to be taken after:

1. Justified actions have been taken to reach the generic Criteria for enabling the transition to an existing exposure situation, and it has been confirmed that any further actions to reach these criteria would do more harm than good;  
2. Confirmation that the source of exposure is fully characterized as normal for all members of the public living in the area;  
3. The situation with regard to exposure has been understood and has remained stable;  
4. Any restrictions on normal living conditions are limited, and provisions are in place to confirm compliance with such restrictions; 
5. Confirmation that interested parties, including the public, have been consulted and are being kept informed about the basis for the adjustment of emergency response actions and for the transition, with the associated health hazards put into perspective.  

16. How shall governments ensure that all these requirements are met?

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

This coordination will also ensure that appropriate emergency arrangements are in place, both on and off the site, in relation to facilities and activities under regulatory control, both within the State and, as relevant, beyond its borders, and also for sources that are not under regulatory control. In particular a regulatory body should require that arrangements for preparedness and response be in place for the on-site area for any regulated facility or activity that could necessitate emergency response actions. In addition, it should ensure that the operating organization is given sufficient authority to promptly take necessary protective actions on the site in response to a nuclear or radiological emergency that could result in off-site consequences.