19–23 Jun 2023
Hofburg Palace & Online
Europe/Vienna timezone

Reconstruction of Synthetic Radionuclide Source Terms Using Bayesian Inference

20 Jun 2023, 13:50
Prinz Eugen Saal

Prinz Eugen Saal

Oral T3.6 Analysis of Radionuclide Monitoring Data O3.6 Analysis of Radionuclide Monitoring Data


Ian Hoffman (Radiation Protection Bureau, Health Canada)


The Forensic Radionuclide Event Analysis and Reconstruction (FREAR) tool performs source reconstruction using a Bayesian inference framework. Using a statistical model of the radionuclide detection system and atmospheric transport models, FREAR infers and reconstructs the best emission source characteristics to fit the supplied observations. This powerful approach provides assessments of source location, release magnitude, release period, compares observed and posterior predicted measurements and ultimately reduces the area of consideration of potential sources.
To test the suitability of FREAR for verification applications, blind synthetic trials were constructed at two different environmental scales, using WRF-HYSPLIT. These two scenarios were then reconstructed by FREAR at three different organizations using different dispersion and meteorology model input (NCEP-HYSPLIT, ECMWF-FLEXPART, CMC-MLDP). The results of the two trials will be discussed, showing that FREAR represents a dramatic improvement in radionuclide event assessment, providing a valuable tool to National Data Centres. The future development of the FREAR tool will be shared.

Promotional text

The detection of CTBT-relevant radionuclides by the MS poses important questions for National Data Centres - where did it come from? how much and when was the material released? The Bayesian inference tool, FREAR, helps answer these questions, supporting verification.

E-mail [email protected]
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Primary author

Ian Hoffman (Radiation Protection Bureau, Health Canada)


Alain Malo (Environment and Climate Change Canada) Andy Delcloo (Royal Meteorological Institute of Belgium) Astrid Suarez Mullins (Air Force Technical Applications Center (AFTAC)) Mr Daniel Chester (Atomic Weapons Establishment (AWE) Aldermaston) John Shuford (Air Force Technical Applications Center (AFTAC)) Kurt Ungar (Health Canada) Matthew Goodwin (Atomic Weapons Establishment (AWE) Aldermaston) Michael Walters (Air Force Technical Applications Center (AFTAC)) Pieter De Meutter (Belgian Nuclear Research Center (SCKCEN)) Stéphane Beauregard (Environment and Climate Change Canada) Zaneta Gacek (Air Force Technical Applications Center (AFTAC))

Presentation materials