Nuclear weapons tests cannot be conducted in secret - UN International Day against Nuclear Tests is on 29 August

STUK’s information centre continuously receives and analyzes data about radioactive substances in the atmosphere produced by approximately one hundred monitoring stations that are located all over the world and utilized to supervise nuclear tests. STUK also has a laboratory that can further analyze particulate samples collected from the air by such instruments. No detectable amounts of radioactivity were released into air during the experiment conducted by North Korea; however, the explosion was also detected at the station of the Institute of Seismology of the University of Helsinki in Sysmä, Finland.

The seismologic station in Sysmä and the STUK laboratory belong to the international Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring system. By using the information provided by the system in September 2017, it was possible to confirm that North Korea did in fact detonate the bomb.

According to STUK Senior Inspector Mikael Moring, the test conducted by North Korea could have been detected and confirmed as a nuclear test even if the country itself would not have reported it.

“The monitoring system covers the entire globe and different monitoring methods that support one another are utilized. The utilized methods as well as the open sharing of data collected in the system between the member countries guarantee in practice that a single country is unable to conduct nuclear tests in secret,” Mikael Moring explains.

The system has been designed to detect an explosion of at least one kiloton, regardless of whether the explosion occurs underground, in the atmosphere or in the sea. In addition to seismic phenomena and radioactivity in the air, the monitoring stations monitor hydroacoustics in the seas around the world as well as infrasound.

Technology developed at STUK is utilized globally

STUK has participated in the development of the technology utilized in the monitoring of the nuclear test ban from the outset. For instance, air collectors have been developed at STUK that are now utilized as part of the CTBTO monitoring network around the world. One such air collector is located on the roof of STUK’s premises in Helsinki as part of Finland’s national radiation monitoring network. STUK has also led the cooperation for developing a specific database for processing the results of radionuclide analyses. In addition to STUK, this database is also used in the national information centres of many other countries.

UN International Day against Nuclear Tests on 29 August

The United Nations has declared 29 August as International Day against Nuclear Tests (https://www.un.org/en/observances/end-nuclear-tests-day).

The international agreement to put an end to all forms of nuclear testing was concluded in 1996; however, the agreement is still not valid as a number of countries have yet to ratify the treaty.

A separate organization, the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Organization (CTBTO), has been established to supervise the agreement.

In Finland, the Ministry for Foreign Affairs is the body responsible for operations relating to CTBTO. STUK is the national information centre of the system. STUK receives and handles information produced by the control network and processes the information to be utilized by the decision-making bodies.