We have, to date, 0 methods of generating electricity at scale that are free of catastrophic failure modes. Solar will not be free of them either, and we don't really have the data yet to figure out how they compare relevant to nuclear ones (which, on balance, are the mildest of all the tested options!). It could do well, it could do badly, but it is not entirely fair to compare a known low risk in nuclear to an unknown risk in solar.
> So you are kind of referring to mass extinction events. no?
No, I'm not. I included a wiki link to the sort of thing I think could be a problem. It doesn't mention extinction.