News Release 

Reconstructing source of radioactive ruthenium

Proceedings of the National Academy of Sciences

A study reconstructs the source of radioactive ruthenium observed over Europe in 2017. In the fall of 2017, low but significant levels of the radioactive isotope ruthenium-106 (106Ru) were detected in the atmosphere above most European countries. The source location and magnitude were unknown at the time and could not be determined based on atmospheric radioactivity measurements alone. Olivier Saunier and colleagues combined environmental measurements with atmospheric modeling to identify the most probable location and magnitude of the source. The method identified the southern Ural Mountains in Russia as the most likely location for 106Ru release. Of the 2 nuclear facilities in this region capable of producing a sufficiently large quantity of 106Ru, the observations were most consistent with the source being located at the Mayak Production Association facility. The authors estimated that approximately 250 TBq of radioactivity was released in total. The authors note that the majority of the estimated release occurred on September 26, 2017, although smaller releases occurred as early as September 23. Based on the estimated location, magnitude, and timing of the source, the authors simulated the dispersion of a 106Ru plume from the Mayak facility. In most cases, simulated 106Ru air concentrations comported with measurements to within a factor of 5. The results suggest that Mayak was the source of the 2017 106Ru plume, according to the authors.

Article #19-07823: "Atmospheric modeling and source reconstruction of radioactive ruthenium from an undeclared major release in 2017," by Olivier Saunier, Damien Didier, Anne Mathieu, Olivier Masson, and Joffrey Dumont le Brazidec.

MEDIA CONTACT: Olivier Saunier, Institut de radioprotection et de Sûreté nucléaire, FRANCE; tel: +33-0660886069; e-mail:


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