Non-natural ruthenium isotope ratios of the undeclared 2017 atmospheric release consistent with civilian nuclear activities

Abstract

A cloud of enhanced ruthenium concentrations has been observed over Europe in 2017, but no country has acknowledged responsibility for this nuclear release. Here, the authors show that the stable isotopic composition of ruthenium emitted from nuclear fuel reprocessing during the 2017 event is consistent with the isotopic signature of civilian Russian nuclear reactor fuel.