Preparatory Commission of the Nuclear Test Ban Treaty Organization [fr]

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  1. CTBTO: history, mission and verification regime ;
  2. CTBTO : governing bodies, executive secretariat and budget ;
  3. CTBTO : French commitment towards the Treaty.

The Comprehensive nuclear Test Ban Treaty (CTBT) is today, with the Non Proliferation Treaty (NPT), one of the pillars of the global architecture for the non proliferation of nuclear weapons and in favour of disarmament.



Negociated between 1994 and 1996, then open for signature on 24 September 1996, the CTBT has been signed by 184 States and ratified by 168 of them (situation on 1st April 2020). For the Treaty entry into force, the negociators have defined a list of countries with nuclear capabilities which ratification is compulsory (whatever the number of States that would have already ratified the Treaty). These States are called Annex II States. On 1st April 2020, eight States belonging to the Annex II have not yet ratified the Treaty : Iran, the United States of America, China, Israel, Egypt, India, Pakistan and North Korea, these last three countries having also to first sign the Treaty. It is also only these last three States that have carried out nuclear tests since 1998 (India and Pakistan in 1998, the Democratic People’s Republic of Korea in 2006, 2009, 2013, 2016 and 2017).

Established in Vienna in 1997, the Provisionnal Technical Secretariat of the Preparatory Commission of the Comprehensive Nuclear Test Ban Treaty Organization is in charge to prepare the entry into force of the Treaty through development and deployment of techniques necessary to monitoring and verification of any form of nuclear explosion in the world.



The goals of the Treaty are defined by the following articles :

« 1. Each State Party undertakes not to carry out any nuclear weapon test explosion or any other nuclear explosion, and to prohibit and prevent any such nuclear explosion at any place under its jurisdiction or control.

2. Each State Party undertakes, furthermore, to refrain from causing, encouraging, or in any way participating in the carrying out of any nuclear weapon test explosion or any other nuclear explosion. »

Verification regime

Different techniques can be found among the global framework of the CTBT verification regime, based on four pillars :

  • The International Monitoring System, IMS, made of 321 monitoring stations and 16 analysis laboratories, carries on seismic, hydroacoustic, infrasound and radionuclide measurements. These measurements are sent to the International Data Centre in Vienna, most of them through quasi live stream, apart from the data related to radionuclides because of the necessary delay to allow sample gathering and "in lab" reckoning ; the CTBTO makes this data avalaible for all States signatories, along with related bulletin analysis, in order to allow States to determine, in full independance, the nature of the detected events. As of today, this network is approximately 85% mission capable and very sensitive, far below the 1 000 kton of TNT that is defined by the Treaty and was able, for example, to detect all four North Korea nuclear tests (2006, 2009, 2013, January and September 2016, September 2017) ;

The International Monitoring System functionning, the technologies used and the French contribution to this system are introduced in the dedicated article "Around the world in 16 stations".

  • The mechanism for consultation and clarification, that allow the States to seek all necessary information to get rid of any ambiguous information on the nature of an event, either through consultations between States or through the intervention of the CTBTO Executive Secretary ;
  • The On Site Inspections, that any State can require in case of persistent doubt. These inspections are meant to gather factual elements and to inquire a potential violation of the Article I of the Treaty. It is based on the convocation, in a very short period of time (around a week), of about fourty non permanent experts specially trained to inspection techniques as mentioned in the Treaty and to on site information research. In order to take place, an inspection has to be approved by the Executive Commission by at least 30 favorable votes out of 51 ; in opposition to numerous verification regimes, such as the OPWC or the IAEA, the CTBT does not propose routine inspection; such inspection can only be implemented after the entry into force of the Treaty ;
  • Confidence measures, which allow States the possibility to voluntary send information priori to an event, such as an important chemical explosion, in order to avoid confusion in data analysis.
  1. CTBTO: history, mission and verification regime ;
  2. CTBTO : governing bodies, executive secretariat and budget ;
  3. CTBTO : French commitment towards the Treaty.

Dernière modification : 09/04/2020

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