A senior scientist from the Vienna-based Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO) has visited the Australian Antarctic Program’s research station on Macquarie Island to inspect the new home of one of the organisation's monitoring stations. The radionuclide station, which is part of a global network that looks for signs of nuclear weapons testing, was moved to a new building because the old one was no longer fit for purpose.

Macquarie Island research station's isthmus with buildings, including a satellite dome, in the background.
The radionuclide monitoring lab sits just behind the ANARESAT dome. Photo: Pete Harmsen

“At Macquarie Island we have a radionuclide station that monitors radioactive content in the air and if we detect noble gases, that would be indicative of a potential nuclear test,” CTBTO radionuclide project manager Nikolaus Hermanspahn said.

“Air is sucked in through a vent and a filter collects all the dust. Then the local operator (usually the station’s Comms Tech officer) takes the filter out and compresses it into a little disc.

“It’s stored for 24 hours and then the particles are counted on a spectrometer to determine the radioactivity content.”

That information is transmitted to the CTBTO's International Data Centre in Vienna for analysis and distributed to all state parties.

Mr Hermanspahn travelled to Macquarie Island on RSV Nuyina’s resupply voyage in May, with colleagues from the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).

The group spent several days on the island, checking that the monitoring equipment was properly calibrated and working efficiently.   

“Macquarie Island is important because we need as much geographical coverage as possible and these big ocean areas are a real challenge,” Mr Hermanspahn said.

“The fact that Macquarie Island is staffed year-round is critical for our operations there. Without the research station we wouldn’t be able to run the monitoring station and that would be a big hole in our network.”

Delegation checks data integrity

ARPANSA carries out Australia's radionuclide monitoring obligations to the Comprehensive Nuclear Test Ban Treaty (CTBT).

The organisation’s scientists monitor treaty compliance through the installation, implementation, and operation of Australian monitoring stations spread across the country, Antarctica, Fiji and Kiribati.

‘Radionuclide monitoring at Macquarie Island in the sub-Antarctic region is important to make sure Australia’s international obligations to the CTBT are met,” ARPANSA’s Monitoring Networks Director, David Hardman, said.

“Our recent trip allowed us to work closely with our CTBTO colleagues in revalidating the station, making sure it meets the high standards set for the International Monitoring System.”

Three men in black stand in a laboratory
David Hardman (left) and Erin McWilliams (centre) from ARPANSA with Nikolaus Hermanspahn from the CTBTO at the radionuclide monitoring lab Photo: Pete Harmsen

"The scope of expertise required to conduct the resupply is really impressive"

Radionuclide monitoring is just one of four technologies used by the international monitoring network which, when complete, will have 321 stations worldwide.

The CTBTO network also includes seismic stations, which monitor shock waves through the ground;  hydroacoustic stations, which pick up sound waves in the ocean; and infrasound stations, which detect ultra-low frequency sound waves inaudible to the human ear.

If a nuclear test is carried out, those systems are likely to detect it first. Radiation levels are then used to corroborate that data.

“Seismic or hydro-acoustic or infrasound stations are good at picking up an explosion but they can’t distinguish if it’s a chemical or nuclear explosion so that’s where the radioactivity part of the network is important,” Mr Hermanspahn said.

“We can pick up a clear signature of a nuclear test to distinguish it from another type of explosion from mining or the like.”

According to the CTBTO’s website, the Comprehensive Nuclear Test Ban Treaty (CTBT) has been signed by 187 countries and ratified by 178.

Only ten tests have been detected since the Treaty opened for signatures in 1996, compared to more than 2,000 over the previous 50 years.

If nobel gases are detected, samples are split and tested again by two different laboratories but it’s up to the state signatories, not the CTBTO, to act.

“The CTBTO does not announce a nuclear test, we just alert state parties and national data centres to the fact that there were some signals at the stations that may indicate a nuclear test,” Mr Hermanspahn said.

“But it’s up to the state parties to make that decision.”

The data collected by the monitoring network also has civil and scientific applications. 

The seismic monitoring network provides real-time tsunami warnings to member states and radiation monitoring tracks the movements of harmful radionuclides if there’s a nuclear emergency like Japan’s Fukushima Daiichi incident in 2011.

“We’re really happy with the new site and confident that this station will continue to provide good data for years to come,” Mr Hermanspahn said.

“I also really appreciated the opportunity to see the effort that goes into sustaining the Macquarie Island research station. The scope of expertise required to conduct the resupply is really impressive.”

A man in black sits at a chair in front of a computer
Nikolaus Hermanspahn is the first representative from the Vienna-based Comprehensive Test Ban Treaty Organisation to visit Macquarie Island. Photo: Pete Harmsen
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