I read 'Nuclear Batteries' and the first thing I think about is the "Lia Radological accident", where three men were exposed and one died.

https://en.wikipedia.org/wiki/Lia_radiological_accident

This incident happened in the country of Georgia, which was part of the Sovjet Union. Which probably already hints towards the root-cause of this incident (they lost track of the devices).

Also: Just because you can, doesn't mean you should.