Lessons learned to action: OSI Workshop-26 gears up for Integrated Field Exercise

The On-Site Inspection (OSI) Workshop-26, which focused on lessons learned from the 2023 Directed Exercises (DEs) and the 2024 Build-Up Exercise (BUE), took place in Vienna from 30 September to 4 October. The workshop marked a significant milestone in the lead-up to the next Integrated Field Exercise (IFE), consolidating experiences and recommendations from the preparatory exercises.

The head of the Organization underscored the necessity of developing all essential components of an on-site inspection, from highly trained inspectors to well-tested equipment and procedures to complex logistical arrangements. He noted that these elements can only be validated through large scale field exercises, which assess operational readiness.

OSI Workshop-26 gathered 76 experts from 41 States Signatories to engage in open dialogue, share insights and collaboratively address challenges faced during the preparatory exercises. Over five days of in-depth technical discussions, participants critically reviewed and reflected on their performance, identified challenges and gaps in inspection techniques and cross-cutting procedures, and worked to develop practical, achievable solutions to ensure optimal preparedness for the next IFE.

Exercises play a vital role in efforts to build up the on-site inspection component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification regime to ensure it will be fully operational upon entry into force. An inspection team with up to 40 international experts will be deployed to search for signs of a nuclear test explosion using a variety of equipment and techniques as listed in the Treaty, including position finding, visual observations, multispectral and infrared measurements, measurements of radioactivity, environmental sampling and analysis, and geophysical seismic and non-seismic techniques.

The ability to gather facts through a thorough, robust and independent on-site inspection is the Treaty’s ultimate verification measure. It provides the strongest assurance that clandestine nuclear tests will be detected and that unfounded accusations can be refuted. 

Focused discussions during OSI Workshop-26 highlighted key lessons and recommendations that will enable the CTBTO to refine its inspection procedures as it prepares to put its surrogate inspectors, equipment and techniques to the test under the challenging conditions of an Integrated Field Exercise. 

Pending the Treaty’s entry into force, the CTBTO will continue to advance its OSI capability through field tests, training, exercises, expert meetings and workshops.