Vienna, 24 November 2025
The Republic of Namibia has confirmed it will host the next on-site inspection (OSI) Integrated Field Exercise, known as IFE26.
Scheduled to take place over six weeks in October and November 2026, it will be the third large scale on-site inspection exercise organised by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). Previous IFEs were held in Kazakhstan in 2008 and in Jordan in 2014.
“While we rely on the International Monitoring System (IMS) for detecting nuclear test explosions, the final confirmation must still come from what is found on the ground, which is where on-site inspection will complete the picture. A CTBTO on-site inspection is designed to provide a clear, shared account for all to see, removing any chance of doubt or misinterpretation,” Executive Secretary Robert Floyd said.
On-site inspection will become operational once the Comprehensive Nuclear-Test-Ban Treaty (CTBT) enters into force and then serve as the final measure of determining whether a nuclear test explosion has taken place. A State Party may request an inspection of an area where it suspects such an event may have occurred, and any request must be approved by the CTBTO Executive Council. Should that happen, a trained inspection team would be deployed to the inspection area to carry out activities using the techniques and procedures set out in the Treaty and its Protocol.
Purpose of an Integrated Field Exercise
Integrated Field Exercises are among the most complex activities conducted by the CTBTO. They test almost every aspect of an on-site inspection, including field operations, inspection techniques, data management, and logistics within a scientifically credible scenario that mirrors real conditions.
“IFE26 is expected to bring together around 250 participants from across the world, who will apply their training and expertise in a scenario designed to be as close to a real on-site inspection as possible and set in a challenging operating environment. The IFE is essential to review and demonstrate current OSI capabilities in a holistic manner, highlight areas for improvement, and further reinforce the robustness and readiness of the OSI regime,” Oleg Rozhkov, Director of the OSI Division said.
Participants will include surrogate inspectors nominated by States Signatories, national technical experts, CTBTO staff and external evaluators. Around 150 tonnes of equipment are expected to be transported to Namibia by sea and by air for the exercise.
Namibia is a long-standing supporter of the CTBT. It signed the Treaty when it opened for signature in 1996 and ratified it in 2001. The country hosts two certified IMS facilities near Tsumeb, auxiliary seismic station AS67 and infrasound station IS35, which contribute to global detection capabilities. Namibia also works closely with the CTBTO on regional capacity building.
Preparations for IFE26
IFE26 builds on a programme of field activities carried out between 2022 and 2025 to strengthen on-site inspection readiness. The Build-up Exercise in Hungary in 2024 served as the final preparatory step, further developing the operational capabilities needed for a full-scale integrated field exercise.
Background
The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosions everywhere, by everyone, and for all time. Adherence to the Treaty is nearly universal, with 187 signatories and 178 ratifying States. To enter into force, the Treaty must be ratified by all 44 States listed in its Annex 2, for which nine ratifications are still required.
The CTBTO has established an International Monitoring System (IMS) to ensure that no nuclear test explosion goes undetected. Currently, 307 certified facilities - of a total of 337 when complete - are operating around the world, using four main technologies: seismic, hydroacoustic, infrasound and radionuclide.
The data collected by the IMS has also been used for disaster mitigation such as earthquake monitoring and tsunami warning, as well as research into fields as diverse as whale migration, climate change and the prediction of monsoon rains.
You can learn more about the Treaty and the Organization at www.ctbto.org and @CTBTO on X, Facebook, and LinkedIn.