Key facts

Participating countries: Austria, Canada, Finland, France, Germany, Ireland, Italy, Japan, Luxembourg, Norway, Romania, Sweden, Switzerland, Ukraine, the United Kingdom and the United States

Key topics:

  • international communication;
  • decision making process in national responses;
  • food safety;
  • emergency assistance.

Key outcomes:

  • strengthen the co-ordination of communications and short-term countermeasures;
  • good practices in decision making process identified;
  • need for more realistic exercise.
Publications and reports


The first INEX exercise was held in 1993 to address the international community need to improve the quality and the co-ordination of emergency response systems on a regional scale, in particular in the case where countries have borders in common, and to help in seeking consensus on approaches to the management of nuclear emergencies between countries which are not necessary linked to each other with a common border or by being situated in the same region. Since the nuclear accidents at Three Mile Island in 1979 and Chernobyl in 1986, many countries had intensified their efforts in emergency planning and preparedness for nuclear accidents in the beginning of 1990s.

In June of 1989, the NEA and the Commission of the European Communities held a joint workshop on emergency planning. The workshop opened with the presentation of an NEA Survey on Emergency Planning Practices and Criteria, and covered topics such as developments concerning the basis for off-site emergency planning, surveillance, monitoring and decision making, and experience from emergency planning and response in the non-nuclear field and design of and experience from nuclear emergency exercises. Workshop participants concluded that the NEA should remain active in the area, and should promote international co-operation on off-site nuclear emergency exercises.

In 1990, the NEA Committee on Radiological Protection and Public Health (CRPPH) created the Expert Group on Emergency Exercises to address those needs. The final trigger for the establishment of INEX series was the Survey on National Practices and Lessons Learnt from Off-Site Nuclear Emergency Exercises, followed by the Workshop on Emergency Exercises in 1991. The participants of this workshop concluded that an international emergency exercise would contribute to the co-ordination of the emergency response systems used in various countries, and that an exercise which would focus on the international policy aspects of emergency arrangements should be proposed to the CRPPH. The timeline below presents the timeline of the key events related to INEX-1 exercises.


INEX-1 was divided in two stages: stage 1) the conduct of a national table-top exercise carried out in each participating country and involving key decision makers and experts responsible for emergency response matters; stage 2) participation in an international meeting of representatives from the participating countries to review the results of the table-top exercises, to share experiences, and to provide indications as to the need for further work in this area.

Between March and May 1993, 16 countries and 1 partner economy performed the exercise. The meeting to review the results took place at the OECD Headquarters, in Paris, in June 1993, thus fulfilling the charge of the CRPPH to the Expert Group on Emergency Exercises.

Exercise description

The INEX-1 was organised as a national table-top exercise at a fictitious country and nuclear power plant to improve transboundary communications and co-ordination. Countries could choose one of the two roles to play (accident country or neighbouring country).

The scenario specificially involved an accident at a fictitious nuclear power station, which was located in an accident country near the border of a neighbouring country. Large quantities of airborne radioactive material were released. The releases and meteorological conditions were designed to ensure that significant contamination levels and the corresponding potential for significant population exposures, would affect areas in both fictitious countries. All participating countries were, however, required to superimpose their normal emergency procedures and provisions in the scenario. To ensure that participants focused on off-site public protection issues, detailed information concerning the nature of the accident and the status of the nuclear power station were not supplied. Environmental radiation and contamination information was supplied in relatively realistic detail and in proper chronological sequence, for participants to make decisions on protective actions.


The objective of the exercise was to identify important policy issues and areas where transboundary communication and co-ordination could be improved. Important issues were the intervention levels which had been adopted by various countries, and how the implementation of countermeasures were co-ordinated, particularly in the border regions. Other issues were to:

  • examine the process for alerting and communicating with neighbouring countries and the international community in the case of a nuclear accident, taking into consideration bilateral/multilateral agreements and international obligations;
  • examine the process for reaching conclusions on the need for national interventions or protective measures;
  • examine actions proposed in relation to the export and import of contaminated food and feeding stuffs;
  • examine the process for identifying the need for and requesting assistance to cope with a radiological emergency.

INEX-1 mainly addressed the phases of the EPR highlighted in the chart below.

INEX-1-Phases of the EPR 

Key outcomes

INEX-1 primarily highlighted the need for improvement of the co-ordination of communications and short-term countermeasures. Moreover, it proved the need for a more realistic exercise, which was taken into account in the organisation of the INEX-2 exercises.
The cross-border aspects of the large-scale nuclear accident simulated during INEX-1 allowed a unique comparison of the responses of the participating countries. Even in those countries with strong ties to and bilateral agreements with their neighbours, the results of
INEX-1 demonstrated that the responses in neighbouring countries may vary significantly, potentially leading to questioning by the populations involved, and perhaps to a loss of confidence in the scientists and governmental agencies responsible for the selection and implementation of protective actions. Such a loss of confidence would make the implementation of protective actions even more difficult.

The monitoring and database management aspects of emergency planning and preparedness are closely tied. This issue found its further evaluation in INEX-2 and resulted in publishing of the NEA report, Monitoring and Data Management Strategies for Nuclear Emergencies. It was further tested in INEX 2000 series.

Some general observations from the exercise on the decision making process were the following:

  • A good principle for emergency planning and decision making is "as normal as possible, as extraordinary as necessary" or "as simple as possible, as good as necessary".
  • Using normal hierarchies and responsibilities, it is useful to avoid reorganisation during an emergency, which can only result in chaos, and facilitate a step-wise return to the normal state during the recovery phase.
  • One conflict to resolve is whether first to restrict and then to relax, or whether to wait to implement restrictions until the situation is better understood. The risk of the former is unnecessary economic and social costs, and the latter is to react too late for certain protective or preventive countermeasures. Both approaches, therefore, have advantages and drawbacks as well as associated psychological aspects.

The detailed evaluation of the following aspects: agricultural, communication, monitoring, decision making, assistance and lessons learnt, together with the INEX-1 recommendations and general discussion may be found in the INEX-1 report.