Russia on Tuesday denied its nuclear facilities experienced any incidents after reports of contamination by the ruthenium 106 radioactive isotope in parts of the country, and said the concentration detected posed little threat.
On Monday, Russia's meteorological service said a station close to the Mayak nuclear facility in Chelyabinsk region in south Urals detected "extremely high pollution" of Ru-106 which exceeded the usual background pollution by 986 times.
But a representative of Rosatom nuclear corporation told AFP "there have been no incidents at nuclear infrastructure facilities in Russia."
Mayak, which is under Rosatom's umbrella, also said Tuesday that the contamination "has nothing to do with Mayak's activities".
It said the dose "poses no danger to human health and lives" as it is 20,000 times smaller than the "allowed annual dose."
The facility, which reprocesses nuclear fuel, added that it has not produced Ru-106 for many years.
The chief of Rosgidromet weather service Maksim Yakovenko on Tuesday also said the concentration detected "poses no danger to population's health", adding that it's not the service's job to detect the source.
On November 9, France's Institute for Radioprotection and Nuclear Safety (IRSN) issued a report saying ruthenium-106 had been detected in France between September 27 and October 13.
It said that the source of the pollution was probably an accident somewhere between the Volga River and the Ural Mountains, adding that the concentrations measured in Europe were not a danger to public health.
It added that the quantity of Ru-106 at the suspected release site was "between 100 and 300 teraBecquerels" which is "very high" and in France would have led to measures to protect the population in the area.
Ruthenium-106 is a product of splitting atoms in a reactor, and is also used in certain medical treatments. It does not occur naturally.