Ruthenium 106 has been detected by several European networks involved in the monitoring of atmospheric radioactive contamination, at levels of a few milliBecquerels per cubic meter of air.  IRSN (the French public expert in nuclear and radiological risks) has therefore undertaken investigations since 3 October to carry out an in-depth assessment of the measurements of ruthenium levels in the territory and to identify the possible origins of the situation encountered.

In France, IRSN has mobilised all its measurement stations for atmospheric monitoring and undertook the analysis of their filter samples. Based on calculations carried out by IRSN, the levels of atmospheric contamination with ruthenium 106 of the order of those observed in Europe are not likely to generate health effects.

By combining levels of contamination observed and numerical simulations performed by IRSN, it appears that the contaminated air masses measured in Europe originate from the southern regions of the Urals. Given the amount of ruthenium 106 that may be at the origin of the air pollution observed in Europe, it appears that measures of protection of the populations could have been necessary in the vicinity of the site of the releases. It should be noted that the detection of ruthenium alone excludes the possibility of an accident on a nuclear power plant, which would result in the presence of other radionuclides. Ruthentium can occur in nuclear fuel cycle installation, in facilities manufacturing radioactive sources or in RTG's (Radioisotope thermoelectric generators) used for the power supply of satellites. Discussions with BfS, the German counterparts of IRSN, show that they reach similar conclusions.

IRSN is continuing its efforts to monitor the level of ruthenium in the territory and its calculations to clarify the origin of the releases and their characteristics.  See the IRSN press release for further details.