Nuclear proliferation watchdog CTBTO is using its world-wide array of monitoring stations to authenticate possible nuclear explosions, including that claimed last month by secretive North Korea. Matthew Stock reports.
North Korea's triumphant announcement on September 3rd saying they've successfully conducted their largest nuclear test to date. Authenticating such reports is down to experts from the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). The Vienna-based nuclear proliferation watchdog has 289 certified technology stations world-wide, with more planned. As well as seismic, hydroacoustic and infrasound sensors; radionulcide detectors like this sample the air for minute traces of nuclear particles. SOUNDBITE (English) ROMANO PLENTEDA, HEAD OF RADIONUCLIDE UNIT IN THE INTERNATIONAL MONITORING SYSTEM (IMS), CTBTO, SAYING: "The particles that are in the air are sampled with the air and collected into filters. The filters will now decay and are then collected in the detectors. Any particulate which has radioactive nature and the foot-print of radiation is then collected in data which are then sent for review to the GCI, the Global Communication Infrastructure." Crucially, explosions can only be classified as nuclear once airborne radioactivity is found, typically in the form of radioactive noble gas xenon. SOUNDBITE (English) FRANZISKA KLINGBERG, RADIONUCLIDE LEAD ANALYST, CTBTO, SAYING: "Once the data that arrives from the station is automatically processed here, the radionulcide analysts look actually at the data and here we can see a typical spectrum for xenon detection. And we're looking for xenon as an indicator coming out of, for example, a nuclear explosion." The scientists have not yet detected airborne nuclear particles after North Korea's announcement. But this simulation uses meteorological data to show the possible path nuclear gases would take. Which monitoring station first picks up the faint traces depends largely on which way the wind is blowing. If a nuclear test happens underground - as is thought to be the case with in North Korea - this can also delay detection until the nuclear gases are more dispersed.