Unfortunately, AskHistorians only deals with what did happen, not what might have happened and I've therefore had to remove your post. However, your question would be perfect for /r/HistoricalWhatIf, should you wish to cross-post.

Edit- actually, on further consideration the crux of the question seems to be about the long term effects of radiation. That actually might be a worthy question to ask over at /r/askscience