Yes, I have read about the Chernobyl disaster.
Typically, the Soviet government tried to cover up the event. I think it was the Swedes who first noticed and measured the radioactivity of the dust cloud from Chernobyl that was passing over them, and alerted the outside world.
I think also there were some heroic Russian first responders who tried to minimize the catastrophe, knowing that the radioactivity they were exposing themselves to would surely kill them.