Verification Regime of the Comprehensive Nuclear-Test Ban Treaty (CTBT) [fr]
Different techniques are part of the broader CTBT verification regime, which is based on four pillars:
- The International Monitoring System (IMS), consisting of 321 monitoring stations and 16 analytical laboratories, performs seismic, hydro-acoustic, infrasound and radionuclide measurements. Measurements reach the International Data Centre (IDC) in Vienna, mostly in (almost) real time, except for those related to radionuclides due to the time required for sample collection and laboratory counting; the CTBTO makes these data and associated analysis bulletins available to signatory States so that they can determine, under full sovereignty, the nature of the events detected. Today, this network is about 85% operational. It is very sensitive, well below the energy of 1000 tons of DTT equivalent as provided for in the Treaty, and has been able to detect, for example, the four North Korean tests (2006, 2009, 2013, January and September 2016, September 2017).
The operating principle of the International Monitoring System, as well as of the technologies implemented and the French contribution to this system, is detailed in the article "Around the world in 16 stations".
- The consultation and clarification mechanism, which then allows States to seek to resolve any ambiguity about the nature of an event either through consultations among themselves or through the CTBTO Executive Secretary;
- On-site inspections, which any State may request in case of persistent doubt. The purpose of these inspections is to collect factual information and to investigate any case of violation under Article I of the Treaty. This is based on the mobilization, within a very short period of time (around one week), of some forty non-permanent experts trained in the inspection techniques provided for by the Treaty and in on-site data collection. To take place, the inspection must have been approved within the Executive Board by 30 votes out of 51; unlike many control regimes, such as the one of the Chemical Weapons Convention (CWC) or the one of the International Atomic Energy Agency (IAEA), the CTBT does not provide for routine or challenge inspections; this provision can only be implemented after the entry into force of the Treaty;
- Confidence-building measures, which allow States to voluntarily transmit pre-event information, such as a major chemical explosion, in order to avoid confusion in the interpretation of data.