Russia said a nuclear material leak detected in Scandinavia did not come from one of its plants.
Nuclear security watchers in Finland, Norway and Sweden said last week that they found above-normal amounts of radioactive isotopes in the atmosphere.
A Dutch public health agency said that after analyzing the data, it believed that the material came “from the western direction of Russia”.
He said the material could indicate “damage to a fuel element”.
But in a statement, Russia’s nuclear power agency said its two plants in the northwest – Leningrad NLP and Kola – were operating normally and there were no leaks.
“There were no complaints about the work of the equipment,” a spokesman for state-owned nuclear power operator Rosenergoatom told Tass news agency.
“The aggregate emissions of all the isotopes specified in the period mentioned above did not exceed the reference numbers.”
The radiation levels at the two plants “remained unchanged in June,” added the spokesman.
Lassina Zerbo, executive secretary of the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO), tweeted on Friday that her Stockholm monitoring station had detected three isotopes – Cs-134, Cs-137 and Ru-103 – at levels higher than usual, but not harmful to human health.
The particles were detected on June 22 and 23, he said.
The Dutch National Institute for Public Health and Environment in the Netherlands said on Friday that the composition of nuclear material “may indicate damage to a fuel element in a nuclear power plant”.
The International Atomic Energy Agency – the UN’s nuclear surveillance body – said on Saturday it was aware of the reports and was seeking more information from member states.