France becomes first Nuclear Weapons State to complete its IMS segment

The International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) has reached a major new milestone with the certification of infrasound station IS25 in Guadeloupe, making France the first Nuclear Weapons State to complete its segment of the global verification network.

The station in the French overseas region in the Caribbean was certified on 25 November as a fully functioning part of the system that monitors round the clock for any sign of a nuclear test. It brings the number of certified facilities to 302, reaching ever closer to the total of 337 foreseen under the CTBT.

“With the certification of infrasound station IS25 in Guadeloupe, I’m pleased to announce France as the first Nuclear Weapons State to complete its segment of the IMS, demonstrating and solidifying its steadfast commitment to the CTBT,” Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) Executive Secretary Lassina Zerbo said in a tweet.

The station is also a unique technical achievement, completed in the face of the global COVID-19 pandemic and presenting multiple complexities and challenges that were overcome through close cooperation between the CTBTO and France’s Commissariat à l'énergie atomique et aux énergies alternatives (CEA).

“Congratulations to the CEA and CTBTO teams that have made possible the reaching of this huge milestone,” tweeted the French Permanent Mission in Vienna. “This is the last step of a 25-year journey started in 1996 when France signed the Treaty. “Let’s finish what we started.””

France hosts a total of 17 facilities around the world, covering all four technologies that make up the IMS: infrasound, seismic, hydroacoustic and radionuclide. It signed the CTBT when it opened for signature on 24 September 1996, and ratified on 6 April 1998.