Key facts

Participating countries: Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, Czech Republic, Denmark, Egypt, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Kazakhstan, Korea, Latvia, Lithuania, Luxembourg, Mexico, Netherlands, Norway, People’s Republic of China, Poland, Portugal, Romania, Russia, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Ukraine, United Kingdom, United States

Participating economy: Chinese Taipei

Participating international organisations: EC, IAEA, WHO, WMO, UNDHA

Key topics:

  • decision making in uncertain conditions;
  • real-time communications;
  • public information;
  • interaction with the media.

Key outcomes:

  • co-ordination of countermeasures;
  • timeliness and completeness of data for decisions;
  • provision of public information;
  • establishment of international exercise culture;
  • monitoring and data management strategies.
Publications and reports


The enthusiastic reception of the INEX-1 exercises resulted in creation of the Expert Group for Nuclear Emergency Matters in 1993. This expert group organised three workshops as a follow-up to the INEX-1 exercises and together with the 1993 exercises, brought a robust basis for the new series of exercises. The workshops covered the topics of the implementation of short-term countermeasures after a nuclear accident (Stockholm, 1994), agricultural aspects of nuclear and radiological emergency situations (Paris, 1995) and nuclear emergency data management (Zürich, 1995).


Exercise description

The INEX-2 exercise was planned as a series of regional, command-post exercises with the simultaneous real-time participation of many countries – including those from Eastern Europe and Asia – and international organisations. Between 1996 and 1999, four regional exercises all having the same objectives, were carried out based on realistic scenarios at nuclear power plants in Switzerland (November 1996), Finland (April 1997), Hungary (November 1998) and Canada (April 1999).

The INEX-2 series was based on and combined with previously planned regional or bilateral exercises which had their own specific objectives. Based on these regional exercises, the objectives to be tested in the international INEX-2 exercise were then added to the national-level command post exercise. This required some compromises for the international exercises, their objectives and scenarios. The advantage of this approach, however, was that organisation of the main exercise was handled by the host countries so that the NEA could concentrate on the international aspects.

The four exercises involved the nuclear power plants and accident scenarios summarised in the table below. After the completion of these four regional exercises, an INEX-2 summary meeting was held in December 1999 to review the experience to date, and to recommend new areas to be addressed by the NEA's programme of work in the future.

Exercise Date Nuclear power plant Scenario
INEX-2 CH November 1996 Leibstadt (BWR), Switzerland Explosion and fire in the turbine building, a pipe-burst in bleed-steam line, release of radioactive steam through broken windows, reactor not affected
INEX-2 FIN April 1997 Loviisa (PWR), Finland Anticipated transient without scram (ATWS), initiated by power failure due to airplane crash, site emergency declaration
INEX-2 HUN November 1998 Paks (PWR), Hungary Large primary to secondary circuit leak, activity release through an open safety valve
INEX-2 CAN April 1999 Darlington (CANDU),Canada Loss-of-coolant accident (LOCA), containment dowsing, possible problem with emergency cooling, time of projected venting


  • decision making based on limited information and uncertain plant conditions;
  • the use of real time communications with the actual equipment and procedures;
  • the public information and interaction with media;
  • the use of real weather for real-time forecasts.

To these general objectives, each participating country and organisation could add its own specific objectives for each exercise. As many participants began to introduce modifications based on experiences and lessons from the first exercises of the series, testing such modifications became important specific objectives for the following exercises. Depending on the location of the respective regional exercise, many countries had the opportunity to play as neighbouring, near and far field countries.

INEX-2 mainly addressed the phases of the EPR highlighted in the chart below.

INEX-2-Phases of the EPR 

Key outcomes

In summarising the experience and lessons learnt discussed during the INEX-2 exercises, four areas of interest were discussed:

  • lessons learnt for decision making based on limited information and on uncertain plant conditions;
  • lessons learnt on the real-time exchange of information;
  • lessons learnt in public and media communications;
  • lessons learnt for the preparation of emergency exercises.

Amongst the most relevant from the INEX-2 exercises:

  • co-ordination of countermeasures;
  • timeliness and completeness of data for decisions;
  • provision of public information;
  • need for the definition of a strategy for informing the media and public; 
  • need find/create efficient methods to monitor the effectiveness of public and media information;
  • clarification of the roles and responsibilities of the international organisations;  
  • creation of an international database for frequently asked questions (FAQ) from real events and exercises;
  • definition of international standards for emergency data transmission.

Moreover, during the early Swiss and Finnish exercises, it became clear that in case of an emergency situation, the selection and transmission of information could be improved to ensure that decisions and public information are based on appropriate and timely knowledge. Therefore, the NEA developed a coherent strategy to

  • better identify key emergency data;
  • improve emergency communication and information management;
  • improve emergency monitoring strategies.

This strategy may be found in the NEA report, Monitoring and Data Management Strategies for Nuclear Emergencies.

Additionally, with the launch of the INEX-1 exercise and the more realistic INEX-2 exercise series, the NEA initiated and established an international nuclear emergency "exercise culture".