This is a non argument. Nobody is seriously proposing coal as an alternative to nuclear. Sure in some countries (e.g. Germany) they phased out nuclear before coal, but there are very different reasons for this, for example they are favoring brown over black coal. That is for different reasons though, largely the political lobby and associated jobs in economically weak regions (note I'm not saying this is right).

However, nobody is proposing coal as a long term solution. Yes one might make the argument that nuclear is safer than coal (however that argument is by no means as clear cut as you make it out too be), but the competition are renewables and neither nuclear or coal come close.