CTBT: Science and Technology Conference 2025 - SnT2025

Session

O2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

O2.3

10 Sept 2025, 16:00

Forum

Conveners

O2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

• Robin Schoemaker (CTBTO Preparatory Commission)
• Man-Sung Yim (Texas A&M University)

153. Estimating source location using the nuclear event zero-time (O2.3-153)

Ms Sara Azimkhani (Atomic Energy Organization of Iran (AEOI))

T2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

Oral

Determining the characteristics of a nuclear event source such as the source location and the event zero-time is an important subject in the Verification Regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). This characterization relies on the accurate analysis of the measured radionuclide data at the stations of the International Monitoring System (IMS). The radionuclide identification...

272. First results of radioxenon detections of SAUNA III and three SAUNA QB networks in Lithuania (O2.3-272)

Dr Rita Plukiene (Center for Physical Sciences and Technology (FTMC), Lithuania)

T2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

Oral

The SAUNA III and three SAUNA QB networks in Lithuania for radioxenon detection in the atmosphere have been successfully launched at the end of 2024. The SAUNA QB modules have been installed on the border of Lithuania: SAUNA QB in Kackonys, on the eastern border, two others SAUNA QB modules on the western and southwestern border of Lithuania at Šventoji and Kybartai towns respectively, and...

715. Impact of Nuisance Background on Source Location Models (O2.3-715)

Mr Paul Eslinger (Pacific Northwest National Laboratory (PNNL))

T2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

Oral

Many source-term estimation algorithms for atmospheric releases assume there is no influence from nuisance sources. However, industrial sources result in a world-wide background of xenon isotopes (Miley and Eslinger 2023) that are also useful for detecting nuclear explosions. A large synthetic data set of atmospheric samples was developed for 384 release events with varying levels of 133Xe...

704. Molten Salt Reactor (MSR) Off-Gas System Efficiency and Its Possible Impact on Radioxenon Release Trajectory Estimations (O2.3-704)

Ms Sri Sundari Retnoasih (National Research and Innovation Agency of Indonesia (BRIN))

T2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

Oral

This study examines the efficiency of off-gas systems in Molten Salt Reactors (MSRs) and their influence on radioxenon release trajectories, with implications for the International Monitoring System (IMS) under the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). Expanding on previous work analyzing radioxenon dispersion from the TMSR-LF1 reactor in China (Retnoasih, 2023), this...

219. New insights into isotopic activity ratios of discharges from nuclear facilities (O2.3-219)

Mr Judah Friese (Pacific Northwest National Laboratory (PNNL))

T2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

Oral

Contrary to expectations based on simulations of neutron irradiation, the discharges from medical isotope production facilities (MIPFs) differ from the radioxenon isotopic activity ratios typically associated with decay chain ingrowth following a nuclear explosion whenever 131mXe is present. This discrepancy is explained in this presentation through fundamental physical principles and...

247. Selecting the Right Noble Gas Tracer: Balancing Experiment Needs and Practical Challenges (O2.3-247)

Dr Christine Johnson (Pacific Northwest National Laboratory (PNNL))

T2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

Oral

Noble gas tracers play a crucial role in environmental transport experiments, offering valuable insights into gas movement and interactions in both the subsurface and atmosphere which can be used to enhance noble gas sampling strategies for On-Site Inspections (OSI) and inform noble gas source terms for the International Monitoring System (IMS). The selection of appropriate noble gas tracers...

436. Subsurface to atmospheric transport of radionuclides using physics-based and machine learning models (O2.3-436)

Dr Akshay Gowardhan (Lawrence Livermore National Laboratory (LLNL))

T2.3 Atmospheric and Subsurface Radionuclide Background and Dispersion

Oral

Radionuclides from underground nuclear explosions can migrate through soil and rock, eventually reaching the surface and entering the atmosphere. Once airborne, they can be carried by winds to detectors located downwind. The detectability of these radionuclides is affected by the geographical and geological features of the test site, particularly in remote areas with complex terrain, which can...