Monitoring atmospheric concentrations of radioxenons is relevant to provide evidence of atmospheric or underground nuclear weapon tests. However, when the design of the International Monitoring Network (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) was set up, the impact of industrial releases was not perceived. It is now well known that industrial radioxenon signature can interfere with that of nuclear tests. Therefore, there is a crucial need to characterize atmospheric distributions of radioxenons from industrial sources—the so-called atmospheric background—in the frame of the CTBT. Two years of Xe-133 atmospheric background have been simulated using 2013 and 2014 meteorological data together with the most comprehensive emission inventory of radiopharmaceutical facilities and nuclear power plants to date. Annual average simulated activity concentrations vary from 0.01 mBq/m3 up to above 5 mBq/m3 nearby major sources. Average measured and simulated concentrations agree on most of the IMS stations, which indicates that the main sources during the time frame are properly captured. Xe-133 atmospheric background simulated at IMS stations turn out to be a complex combination of sources. Stations most impacted are in Europe and North America and can potentially detect Xe-133 every day. Predicted occurrences of detections of atmospheric Xe-133 show seasonal variations, more accentuated in the Northern Hemisphere, where the maximum occurs in winter. To our knowledge, this study presents the first global maps of Xe-133 atmospheric background from industrial sources based on two years of simulation and is a first attempt to analyze its composition in terms of origin at IMS stations.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016JD024872

Characterization of Xe‐133 global atmospheric background: Implications for the International Monitoring System of the Comprehensive Nuclear‐Test‐Ban Treaty

Spalax™ new generation: A sensitive and selective noble gas system for nuclear explosion monitoring

Paradigms and commonalities in atmospheric source term estimation methods

. On 3 September 2017 official channels
of the Democratic People's Republic of Korea announced the successful test of
a thermonuclear device. Only seconds to minutes after the alleged nuclear
explosion at the Punggye-ri nuclear test site in the mountainous region in
the country's northeast at 03:30:02 (UTC), hundreds of seismic stations
distributed all around the globe picked up strong and distinct signals
associated with an explosion. Different seismological agencies reported body
wave magnitudes of well above 6.0, consequently estimating the explosive
yield of the device on the order of hundreds of kT TNT equivalent. The
2017 event can therefore be assessed as being multiple times larger in energy
than the two preceding North Korean events in
January and September 2016. This study provides a multi-technology analysis of the 2017 North Korean event
and its aftermath using a wide array of geophysical methods. Seismological
investigations locate the event within the test site at a depth of approximately
0.6 km below the surface. The radiation and generation of P- and S-wave energy in
the source region are significantly influenced by the topography of the Mt.
Mantap massif. Inversions for the full moment tensor of the main event reveal a
dominant isotropic component accompanied by significant amounts of double couple
and compensated linear vector dipole terms, confirming the explosive character
of the event. The analysis of the source mechanism of an aftershock that occurred
around 8 min after the test in the direct vicinity suggest a cavity
collapse. Measurements at seismic stations of the International Monitoring
System result in a body wave magnitude of 6.2, which translates to an yield
estimate of around 400 kT TNT equivalent. The explosive yield is possibly
overestimated, since topography and depth phases both tend to enhance the peak
amplitudes of teleseismic P waves. Interferometric synthetic aperture radar
analysis using data from the ALOS-2 satellite reveal strong surface deformations
in the epicenter region. Additional multispectral optical data from the Pleiades
satellite show clear landslide activity at the test site. The strong surface
deformations generated large acoustic pressure peaks, which were observed as
infrasound signals with distinctive waveforms even at distances of 401 km. In
the aftermath of the 2017 event, atmospheric traces of the fission product
 133Xe were detected at various locations in the wider region. While
for 133Xe measurements in September 2017, the Punggye-ri test site is
disfavored as a source by means of atmospheric transport modeling, detections in
October 2017 at the International Monitoring System station RN58 in Russia
indicate a potential delayed leakage of 133Xe at the test site from the
2017 North Korean nuclear test.

/pdf/a-multi-technology-analysis-of-the-2017-north-korean-nuclear-rc7szcj3iy.pdf

M. Aldener

Papers

Radioxenon detections in the CTBT international monitoring system likely related to the announced nuclear test in North Korea on February 12, 2013.

Measurement of radioxenon and radioargon in air from soil with elevated uranium concentration

Measurement of radioxenon and radioargon in soil gas collected in the region of Kvarntorp, Sweden.