Note that cost would also include getting rid of the nuclear waste, which AFAIK is still not a solved problem.
E.g. you could send the waste via rockets to thes sun, but that would be very costly ;-) The problem with the statistics is also that we cannot rely on averages here. E.g. one big accident might cause huge environmental issues. Estimating accurately how likely that is seems difficult to impossible
Regarding nuclear waste: first off, the amount of nuclear waste generated today is drastically less than in the past. During WWII and the Cold War era the methods for processing nukes was extremely crude, resulting in an embarrassing amount of waste, which we are still dealing with today. Today, the amount of waste is small fraction of that. Second, the waste problem has been solved by vitrification. Vitrification takes nuclear waste (in liquid or solid form) and blends it with molten glass in a high-strength steel casing. When it cools, it becomes solidified. Then it can be stored in a remote location. Vitrified nuclear waste poses no acute danger to humans and IMHO is much preferred to the damaging effects of fossil fuels which include both harmful pollutants (Particulate Matter, NOx, Ozone, etc.) and dramatic acceleration of climate change.
Firstly, it's not really waste. Only a fraction of useful energy has been extracted & there is a lot of useful elements mixed in due to all the transmutations and fision going on. There are techniques to reprocess used nuckear fuel into more fuel and other useful substances but there is often no political will & a lot of noise from people protesting agains anything nuclear that prevents used up fuel from being properly reused.