01 Overview
In late September and early October 2017, elevated levels of radioactive ruthenium-106 were detected by monitoring stations across Europe - from Italy to Norway. The plume was traced back to the Southern Ural region of Russia, specifically to the Mayak nuclear facility.
02 Cause
The precise cause was never officially confirmed by Russia. European nuclear safety agencies concluded the most likely source was the production of cerium-144 at Mayak for a physics experiment, or a satellite re-entry burning up a radionuclide power source. Mayak is the only facility in Russia producing such materials.
03 Impact
Ruthenium-106 concentrations detected in Europe were far below harmful levels. At the likely source, models calculated concentrations could have been hundreds to thousands of times higher. Russia's Roshydromet confirmed elevated readings at multiple Russian monitoring stations.
04 Response
Russia's Rosatom initially denied any incident. Only after sustained pressure from European counterparts did Russia acknowledge "elevated environmental contamination" in the region near Mayak. No formal accident report was published.
05 Legacy
The incident highlighted continuing weaknesses in nuclear transparency, particularly in Russia. It demonstrated the sensitivity of European radiation monitoring networks and the ongoing pattern of Russian opacity regarding nuclear incidents - a pattern with deep roots going back to the 1957 Kyshtym disaster.