Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization

Logo CTBTO

The Provisional Technical Secretariat of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO PrepCom) has been operational in Vienna since March 1997.

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans nuclear explosions on the Earth's surface, in the atmosphere, underwater and underground. It is a cornerstone of the international regime on the non-proliferation of nuclear weapons and an essential foundation for the pursuit of nuclear disarmament. The Treaty will enter into force after it has been ratified by 44 specific nuclear technology holder countries listed in its Annex 2 (Status of Signature and Ratification). Upon signing the Treaty, a state becomes a member of the Preparatory Commission. Austria has been a member of the CTBTO PrepCom since the CTBT's opening for signature on 24 September 1996.

The Commission's main tasks are to promote the ratification of the CTBT, to carry out the necessary preparations for the entry into force of the Treaty and its effective implementation and to establish the CTBT's verification regime.

As part of the verification regime the International Monitoring System (IMS) will, when complete, consist of 321 monitoring stations and 16 laboratories worldwide to monitor the planet for signs of nuclear explosions. The IMS uses seismic, hydroacoustic, radionuclide and infrasound technologies to monitor the atmosphere, the underground and the oceans. The radionuclide laboratory at Seibersdorf in Austria was the first to be officially certified as an IMS facility in 2001. The data from the global monitoring stations are processed and analysed at the International Data Centre in Vienna and distributed to the CTBTO's Member States. As final verification measure on-site inspections (OSI) can be carried out once the CTBT is in force.