The source of a gigantic leak of radioactive material that swept across Europe in 2017 has been traced back to a Russian nuclear facility which appears to have been preparing materials for experiments in Italy.
The leak of radioactive ruthenium released up to one-hundred times the amount of radiation into the atmosphere than the Fukushima disaster.
The Institute for Radioprotection and Nuclear Security in Paris found the source was in the Southern Urals where the Mayak nuclear facility is located.