Swedish Defence Research Agency

11 November

FOI makes the world safer and more secure

FOI’s experts apply their unique competence in detecting nuclear weapons tests to make the world a safer place. Their detectors are part of a global system for rapid determination of whether and where a nuclear test has occurred. This is world-leading, cutting-edge technology.

Photo from the tests

World leading research that supports nuclear disarmament is conducted here. Photo: FOI.

A drilling rig in Kvarntorp, outside Kumla, pulls up a long drill bar covered in black clay from uranium-rich ground. FOI’s researchers stand watching nearby, ready with their measuring instruments. World-leading research that supports nuclear disarmament is in action here.

“We want to know more about the background radiation so we can be more certain about whether a registered level of radiation is coming from a natural source or from a nuclear explosion,” says Mattias Aldener, Deputy Research Director for Nuclear Weapons-related Issues.

It all has to do with the noble gas, xenon. When a nuclear device is tested underground, xenon, among other things, is released. An elevated level of the gas is a sure sign of a nuclear explosion. But, because the gas is found naturally in the ground, an accused nation can claim that natural background radiation is to blame.

“That’s why we’ve collected a number of ground gas samples around Kvarntorpshögen, in Närke, an area with high levels of uranium in the ground, and therefore naturally high levels of xenon, although these levels are completely harmless for people,” says Tomas Fritioff, another researcher in the section for Nuclear Weapons-related Issues.

An important jigsaw piece of the global system

For several years now, FOI’s researchers have been developing systems for CTBTO, the organisation that monitors compliance to the global nuclear-test-ban treaty.

“The system is called SAUNA and we’re now in its third generation. The systems are placed in half of the 40 or so places around the world that measure noble gas and are part of the global monitoring system that CTBTO runs,” says Mattias Aldener.

Every day, round the clock, atmospheric levels of radioactive xenon are checked, particle samples taken, and seismological and hydroacoustic signals, as well as infrasound, are measured in order to detect nuclear weapons tests. The results are then automatically sent to CTBTO – in Vienna – which then forwards the information to the treaty’s signatory states.

This Swedish cutting-edge technology is very much an important piece of the complex jigsaw of the global system.

“We are world leaders in the measurement and analysis of xenon; the reason is that we’ve worked in this area for so long and concentrated on reliable systems,” says Mattias Aldener.

SAUNA is a monitoring system that is part of a global network of 300 monitoring stations that have the task of supporting CTBTO in its efforts to verify compliance to the ban on nuclear weapons testing. SAUNA is world-renowned for its measurements of atmospheric radioactivity. FOI had already developed the first prototype of the system in 2000. In 2006, the system attracted attention when it detected xenon from a North Korean underground nuclear test. Today, mobile equipment is also available for measuring xenon at a suspected test site.