The CTBT prohibits all nuclear test explosions, whether for military or peaceful purposes. It contains a special clause on its entry into force: under Article 14, all 44 states listed in Annex 2 to the treaty (known as Annex 2 states) must have ratified the treaty before it can officially enter into force. These 44 states had nuclear reactors or nuclear test reactors in operation at the time of the treaty negotiations and took part in the treaty negotiations in 1996. Switzerland, also an Annex 2 state, signed the CTBT in September 1996 and ratified it on 1 October 1999.
A key element of the CTBT is the ability to monitor compliance with the treaty in order to detect nuclear tests anywhere in the world. To enable this, the treaty provides for the establishment and operation of a global verification regime consisting of the following components:
- International Monitoring System (IMS)
- International Data Centre (IDC)
- Consultation and clarification process
- Global communications infrastructure
- On-site inspections
- Confidence-building measures
An official CTBTO Preparatory Commission was set up in 1996 to drive forward the development of this global verification regime and to make further preparations for the period after the treaty's entry into force. All states that have signed the CTBT are represented in this Commission.
The CTBTO has two subsidiary bodies: Working Group A (WG A) on administrative and budgetary matters and Working Group B (WG B) on verification issues. There is also an Advisory Group on financial, budgetary and associated administrative issues. The Working Groups make proposals and recommendations for consideration and adoption by the Preparatory Commission at its plenary sessions.
More information
- CTBTO
- Status of signature and ratification
- Lecture 'Science Meets Diplomacy and World Security' given at ETH Zurich by Lassina Zerbo, former Executive Secretary of the CTBTO Provisional Technical Secretariat, to mark the 20th anniversary of Switzerland's ratification.