|Russian RTG for lighthouses and abandoned navigation beacons|
In the Russian far north and Siberia, the Soviet Union equipped around a thousand beacons and uninhabited lighthouses with thermoelectric generators called RTG. These RTGs use the energy of radioactive decays of strontium-90, a radioisotope much cheaper than plutonium-238. These generators were often left abandoned after 10 years of operation. Scrap merchants, unaware of the risks of radioactive contamination, trying to retrieve the metal casings have vandalized some of them.