Short summary: Soviet engineers installed RTG powered radio relays to support the construction of a damn in Georgia. Political instability lead to the abandonment of the RTGs. Someone scavenged the generators and removed the radioactive cores from them.
Two of the radioactive sources were discovered by men gathering firewood in the forest. They decided to bring them to their camp(!) and cozy up to them to keep warm during the night(!!). Despite showing symptoms of radiation poisoning they kept the cores on their person while loading their truck(!!!). They all suffered terrible radiation injuries.
There are more sources "lost" from the same batch which remains unaccounted for to this day.
Yeah the URSS made routine use of RTGs throughout their territory (pretty logically as it's so vast and low-density electrification can't reach everywhere), and those routinely got misplaced. Things got worse after the fall of the URSS too e.g. a helo dropped two RTGs from 50m while airlifting them in 2004.
Yes, there's a Russian movie with a guy that is guarding a weather station in the North and playing games all day. He somehow gets into a conflict with his supervisor, dissasembles a RTG beacon and uses the Strontium 90 to poison his supervisor's dried fish supply. They both get irradiated and the military cleans up the mess.
Compact electrical generators powered by heat from radioisotopes have been under development in the United States since the early 1950s for space, marine, and terrestrial uses. Essentially all the generators developed for marine and terrestrial uses have been powered by 90 Sr. This report summarizes the development work done by Oak Ridge National Laboratory (ORNL), Hanford Atomic Products Operation, and Martin Company, Nuclear Division, which led to the production of 90 Sr heat sources for use in the generators.
It was a natural choice since strontium 90 is an inevitable byproduct of operating any fission reactor, and was readily available as a coproduct from weapons plutonium production reactors. Making better RTG isotopes like plutonium 238 required additional infrastructure.
Short summary: Soviet engineers installed RTG powered radio relays to support the construction of a damn in Georgia. Political instability lead to the abandonment of the RTGs. Someone scavenged the generators and removed the radioactive cores from them.
Two of the radioactive sources were discovered by men gathering firewood in the forest. They decided to bring them to their camp(!) and cozy up to them to keep warm during the night(!!). Despite showing symptoms of radiation poisoning they kept the cores on their person while loading their truck(!!!). They all suffered terrible radiation injuries.
There are more sources "lost" from the same batch which remains unaccounted for to this day.