The U.S.S.R. had several nuclear accidents prior to Chernobyl, all of which went unreported for many years. I’m reading “Midnight in Chernobyl” by Adam Higginbotham. It’s very well sourced, and lays out the history of nuclear energy production in the U.S.S.R. from its beginning.
I always thought it was stupid that after Russia irradiated all of Europe, Western Europeans were still protesting America hot and heavy.