Inspection Phases

During IFE14 the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) will exercise each phase of an on-site inspection (OSI), from the receipt of the request through the conduct of inspection activities to reporting preliminary findings and departure. Aspects of some phases will not be practised in full or time-compressed to reflect exercise constraints. The four main phases are: 


Launch Phase

Equipment for an on-site inspection is kept at the CTBTO’s storage facility located near Vienna.

An OSI is initiated by a request from a State Party on the basis of a suspicious event. Such an event would most likely have been detected by the International Monitoring System (IMS), but data produced by national technical means of verification can also be invoked to justify an OSI request.

The request for an OSI triggers a chain of activities including:

  1. The CTBTO's Director-General communicates with the State Parties and works with the organization's executive body, the Executive Council, to either approve or refuse the request within 96 hours of receiving it.
  2. At the same time, an Operations Support Centre (OSC) is established at the CTBTO Headquarters to initiate all administrative and operational tasks to get the inspection team in the field as soon possible after the Executive Council approves an OSI.

The launch phase finishes with the approval of the OSI when the Director-General issues the finalized inspection mandate outlining the details of the planned inspection.

Deploying the inspection team into the field is extremely time-critical because there is only a narrow time window during which some of the conclusive evidence of a nuclear explosion can be obtained (see timeline below).

From when the Director-General communicates the request for an on-site inspection to the Executive Council, the organization has only six days to get the inspection team on the ground.

Pre-Inspection Phase

The installation of the base of operations involves moving tons of scientific and non-scientific equipment.

The pre-inspection phase covers the arrival of the inspection team in the country where the OSI is to take place. This involves a range of procedures at the point of entry (negotiations, briefings, equipment checking), the transfer of the inspection team from the point of entry (usually an airport) to the inspection area, and establishing the base of operations.

Inspection Phase

The inspection phase is commonly divided into two parts – an initial period and a continuation period. During the initial period, the inspection team begins with the least intrusive techniques and submits a progress report to the Executive Council no later than 25 days after the inspection has been approved.

If the Executive Council allows the inspection to continue, the inspectors can use more intrusive techniques such as ground penetrating radar and active seismic surveys. During IFE14, the inspection team will test almost all the techniques approved by the Treaty.

Post-Inspection Phase

The inspection team dismantle the base of operations during Build-up Exercise IV.

Once the inspection is declared over, the inspection team submits a report of its activities and findings along with a description of the cooperation granted by the inspected State Party. The Director-General forwards the report to all States Parties and the Executive Council which assesses whether non-compliance with the Treaty has occurred.

In parallel, the inspection team dismantles the base of operations, repacks all equipment and departs from the inspected State Party.

Timeline of an On-site Inspection as specified in the Comprehensive Nuclear-Test-Ban Treaty

Reproduced with permission of the Defense Treaty Inspection Readiness Program