Radiation sensors in Stockholm have detected higher-than-usual but still harmless levels of isotopes produced by nuclear fission, probably from somewhere on or near the Baltic Sea, a body running a worldwide network of the sensors said on Friday. The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) oversees a network of hundreds of monitoring stations that use seismic, hydroacoustic and other technology to check for a nuclear weapon test anywhere in the world. That technology can, however, be put to other uses as well. One of its stations scanning the air for radionuclides – telltale radioactive particles that can be carried long distances by the wind – detected unusually high levels of three radionuclides earlier this week: caesium-134, caesium-137 and ruthenium-103.
Reuters 26th June 2020 read more »