In the vast and empty territory of Russia there is a need to power small autonomous weather stations, lighthouses, etc. reliably, day and night, winter and summer. The solution was micro-scale 230W Strontium-90 thermionic generators, shoebox sized or so. These were similar to 238Pu ones that power Mars orbiters, rovers and such. The decay generates heat, which is used to heat a thermopile (two dissimilar metals brazed together). NASA also uses pencil eraser sized 238Pu pellets in a couple dozen places per craft to keep things warm (1 W heat). The Voyager spacecraft are both still operational in deep space after 50 years or so, with reduced power.
Anyway the stations in Russia were so remote that the reactors were installed unshielded. Occasionally the random trapper or such wandered by, noticed the heat, and cozied up during a cold winter's night. In the morning they woke up dead.