Global Nuclear Emergency Preparedness Put to the Test in Massive IAEA-Led Simulation

On 25 June 2025, the International Atomic Energy Agency (IAEA), in concert with over 75 countries and 10 international organizations, concluded its largest and most ambitious nuclear emergency exercise to date — ConvEx-3 (2025). The 36-hour drill simulated a major radiological release from Romania’s Cernavodă Nuclear Power Plant, testing the world’s collective ability to respond to such a catastrophic event in real time.

Initiated on 24 June and concluding at 17:45 CEST on 25 June, the simulation was the latest in a series of comprehensive ConvEx-3 exercises held every three to five years. These drills are designed to rigorously evaluate national and international nuclear emergency preparedness frameworks, in accordance with global conventions.

Simulation Scenario and Objectives

This year’s ConvEx-3 simulated a severe accident involving the release of radioactive materials at Cernavodă — Romania’s only nuclear power facility. The objective was to test:

• Real-time international coordination

• Public communication effectiveness

• Medical and logistics preparedness

• Radiation monitoring and assessment protocols

• Cyber and physical security integration

Participating states were required to make decisions swiftly, share updates transparently, and launch immediate protective actions to safeguard public health and the environment.

Key Innovations and Breakthroughs

This year's exercise featured several innovations that reflect the evolving nature of nuclear emergency preparedness:

1. Enhanced Regional Collaboration

Neighboring countries Bulgaria and the Republic of Moldova actively coordinated border-crossing response efforts, illustrating the importance of harmonized actions during transboundary radiological emergencies. This included synchronized shelter-in-place orders and joint public advisories.

2. Incorporation of Security Threats

For the first time, ConvEx-3 included simulated cyberattacks on nuclear plant control systems and attempted physical intrusions. These additions acknowledged the increasing convergence between nuclear safety and nuclear security in the 21st century.

3. Advanced Crisis Communication Strategies

A sophisticated social media simulator was deployed to evaluate how emergency communications are disseminated to the public. The test included real-time misinformation management, community engagement, and multilingual outreach.

4. Deployment of International Assistance Teams

Under the IAEA’s Response and Assistance Network (RANET), expert teams from Bulgaria, Canada, France, Lithuania, Moldova, Sweden, and the United States were dispatched. These teams conducted joint aerial and ground-based radiation monitoring, data sharing, and equipment deployment exercises.

Feedback and Next Steps

Carlos Torres Vidal, Director of the IAEA’s Incident and Emergency Centre, emphasized the significance of global unity during such complex exercises. “The ConvEx-3 (2025) demonstrated the strength of international cooperation in nuclear emergency preparedness,” he said. “By working together in realistic scenarios, we enhance our collective ability to protect people and the environment.”

Over the coming weeks, the IAEA will analyze participant feedback to highlight best practices and identify areas for improvement. The final after-action report will inform not only future exercises but also international policy and operational planning.

Road to EPR 2025

Insights from ConvEx-3 will contribute directly to preparations for the International Conference on Nuclear and Radiological Emergencies (EPR 2025), to be held in December in Riyadh, Saudi Arabia. This high-level event will serve as a platform for nations and institutions to reflect on global nuclear emergency preparedness, resilience building, and the integration of emerging threats.

A Stronger Global Shield

Exercises like ConvEx-3 reaffirm the global community’s commitment to proactive nuclear safety and emergency response. As threats evolve and technologies advance, such simulations are critical in ensuring that all stakeholders — from national agencies to international partners — remain prepared to respond swiftly, safely, and collaboratively.