International Nuclear Emergency Exercises (INEX)

About INEX

The NEA has a long tradition of expertise in the area of nuclear emergency policy, planning, preparedness and management. Through its activities in this field, the Agency offers its member countries unbiased assistance on nuclear preparedness matters, with a view to facilitating improvements in nuclear emergency preparedness strategies and response at the international level. The 1986 Chernobyl and 2011 Fukushima Daiichi Nuclear Power Plant accidents demonstrated that such events have international consequences, highlighting the need for international co‑operation, and leading to improvements in the areas of international communication, information exchange and harmonisation of response actions between countries. 

The NEA Committee on Radiological Protection and Public Health (CRPPH), through various sub-groups, has focused on improving the effectiveness of international nuclear emergency preparedness, response and recovery. Part of its work programme is set on exploring and developing new concepts and future procedures to enhance national and international preparedness and response management. A central approach to this has been the preparation and conduct of the International Nuclear Emergency Exercise (INEX) series.

History and context

The effectiveness of existing nuclear emergency response plans and procedures needs to be regularly tested and proven. In most countries, nuclear emergency exercises, drills, and tests are regularly performed at the local, regional, and national levels. To explore the international aspects of nuclear accidents, the NEA initiated and established an international nuclear emergency "exercise culture", starting with the 1993 INEX-1 table-top exercise, the first such exercise to be carried out at the international level. Between 1993 and 2017 the NEA organized 9 international exercises, each having the participation of national emergency management structures from 20 to 50 NEA member and non-member countries, and up to 6 other international organizations. The table and picture below give a brief overview of these exercises, and exercise details can be found by following the links on the left-hand-side.

Programme Exercise year Number of
Number of
Exercise type Scenario type
INEX-1 1993 16 0 Table top Fictitious NPP
INEX-2 Switzerland 1996 30 4 Command centre National NPP exercise
INEX-2 Finland 1997 27 6 Command centre National NPP exercise
INEX-2 Hungary 1998 33 4 Command centre National NPP exercise
INEX-2 Canada 1999 31 5 Command centre National NPP exercise
INEX 2000 2001 55 5 Command centre National NPP exercise
INEX-3 2005 15 2 Table top Large-scale contamination
INEX-4 2010 17 1 Table top Improvised nuclear device/radiological dispersal device
INEX-5 2016 22 1 National and regional table top Multi-unit




National Table Top

Long-term Recovery (existing exposure situation)


Objectives Early phase/communication/decision making process in national responses/food safety/emergency assistance Decision making in uncertain conditions/real time communication/public and media interactions Monitoring and data management strategies for nuclear emergencies/international coordination/aspects of the Convention on Third Party Liability Consequence management/long-term issues/decision making in the medium- and longer-term Post-crisis emergency management/response to widespread radiological contamination of the urban environment Notification and communication aspects/transboundary aspects/interfaces/identifying and obtaining resources tbc
Key outcomes Strengthen the coordination of communications and short-term countermeasures/good pracices in decision making process identified/ need for a more realistic exercise Strengthen the coordination of communications and short-term countermeasures/good pracices in decision making process identified/need for a more realistic exercise Need for information exchange using new technologies/information retrieval using Internet technology as a part of emergency management procedures/decision on national level whether internet technology should be used for information dissemination/implementation of new procedures for posting information on a web site/one official platform for the exchange of emergency information Importance of stakeholder involvement in later phases of consequence management/decision making and approaches to stakeholder communication interaction and interdependency/deeper insight on liability/compensation issues Radiological dispersal device scenario similarities to large-scale nuclear emergencies/improvement and development of contingency plans, mass casualty/decision making in the face of professional differing opinion/optimisation strategies/transition to recovery processes Improvements required in the following areas; real-time communications; non-radiological public health aspects of radiation planning and response, including psychosocial and other societal impacts of evacuation, sheltering and relocation; recommendations for building nationally adapted frameworks for recovery in NEA member countries; benchmarking of dose projection code outputs based on same (or very similar) inputs; WPNEM member country updates of Protective Measures Handbooks; involvement of decision makers in the planning and implementation of protective action strategy. tbc

The INEX-1 table top exercise brought together national nuclear emergency response organisations to address a simulated accident at a hypothetical reactor near the border of two fictitious countries. The results of this exercise highlighted the need for more detailed study of international issues, leading to the development of the INEX-2 series.

Conducted between 1996 and 1999 and involving the simultaneous play of over 30 countries and 4 international organisations, the four INEX-2 exercises were built upon pre-planned national-level exercises at existing power plants in Switzerland, Finland, Hungary and Canada. The INEX-2 exercises used real national and international emergency response centres, their hardware, procedures and personnel to address in real-time, a simulated accident at a real reactor. In addition to testing existing emergency management arrangements, procedures and communications in real-time, these exercises were intended to investigate processes for decision making based on limited information, as well as the management of public and media information.

A fifth exercise, INEX 2000, was carried out in 2001, and involved 57 countries and 5 international organisations. Over a decade of nuclear emergency management at the NEA. Similar in scope to INEX-2, this exercise was organised under the auspices of the Inter-Agency Committee on Response to Nuclear Accidents. It was designed to test the implementation of concepts and lessons learnt from the INEX-2 series, including the testing of new web-based data management and monitoring strategies, and the co-ordination of media information. This exercise also addressed for the first time, through an international workshop, questions of civil liability following a nuclear emergency.

Starting with INEX-3 (2005-2006), the international community began looking at the issue in longer-term consequence management. This third series of INEX exercises focused on consequence management issues that would likely arise as a result of a nuclear or radiological emergency that has led to significant contamination of the populated environment.  INEX-3 was designed to deliver tangible benefits to participant countries in the form of greater understanding of the challenges to be faced after the emergency phase of an incident has passed, the ability to compare national practices with other countries, and the opportunity to identify areas for improvement in consequence management that could be usefully addressed by the international community.   In order to build on the momentum of INEX-3 and the work of various INEX-3 follow-up activities, the WPNEM launched in 2008 the development cycle for a new INEX-4 international emergency exercise.  INEX-4 focused on issues in consequence management and transition to recovery in response to malicious acts involving the release of radioactive materials in an urban setting. Recognising that the arrangements for managing these events may vary between countries, the goal of INEX-4 was to provide a basis for enhancing emergency management through the exchange of exercise experiences from participating countries and identification of good practices and common issues.

Since the 2011 Fukushima Daiichi nuclear power plant accident, it has been recognised that notification, communication, and identifying and obtaining resources during catastrophic events can be difficult. The need for established protocols, policies, and procedures amongst and between country entities is critical for minimising negative impacts. Therefore, it was viewed as beneficial to design an exercise that provided a basis for enhancing national and international emergency management arrangements related to those issues, through the exchange of exercise outcomes and experiences from participating countries in order to identify good practices and common issues to be addressed. Those issues were addressed during the INEX-5 series.

Preparations for the next INEX exercise, INEX-6, are underway. The exercise will focus on the planning and preparedness for the long-term recovery phase after termination of a nuclear or radiological accident (existing exposure situation). This extremely complex and multi-dimensional exercise will serve to identify gaps in policy, preparedness and regulation. It will provide an opportunity for participating countries to test and demonstrate the value of the changes put in place nationally, regionally and internationally following the Fukushima Daiichi nuclear power plant accident, as well as to assess the efficiency of the guidance and methods developed in this regard by the ongoing activities of the Committee of Radiological Protection and Public Health (CRPPH).

Since the beginning of the INEX series, various aspects of nuclear emergency preparedness were studied. Each edition was oriented to test pre-established objectives concerning the selected phase and/or selected aspects of nuclear emergency preparedness and response (EPR). The overall goal of the entire series is to provide a tool enabling participants to perform a comprehensive study of all phases of the EPR and establish a forum for knowledge and experience sharing. The figure below presents the subsequent phases of EPR.

The exercises provide an excellent basis for the review of both national and international arrangements. The objectives of each series are agreed upon by the participants in advance and are constructed to meet their particular needs. Following each exercise, each country completes a standard questionnaire to record observations, lessons and issues for submission to the NEA. This feedback forms the basis of the follow-up INEX International Evaluation Workshops or topical Sessions organised by NEA. The workshops allow participants to exchange and analyse experience from the national exercises and identify cross-cutting issues or gaps impacting multiple states. An important outcome is the identification of good practices, as well as key needs for future work that would benefit from international co-operation.


The International Nuclear Emergency Exercise (INEX) series has supported the NEA membership since 1993 in improving the international aspects of nuclear or radiological accident emergency, preparedness and response. Participants in these INEX exercises share information, data, knowledge and experience to test all aspects of emergency management systems and approaches, identify gaps and provide recommended strategies to improve nuclear emergency management worldwide. The sixth in the series, INEX-6, will focus on the planning and preparedness for the long-term recovery phase (existing exposure situation) after a nuclear or radiological accident.