You say that as if it's a given that it will always leak slowly. What % of the spent fuel actually ended up being leaked across the couple decades of storage we have had now? What effects did it have? How does the human cost stack up against mining activities we would need for the massive amounts of wind turbines and solar panels when we cut out nuclear's base load function completely?
Nuclear waste leaking into the groundwater? Sure, if someone is being absurdly callous. But if we're going to invent a villain with no morals as just dumps the stuff then we might as well do the same for any other form of energy.
I prefer to assume we're comparing competent operators of any energy type in our portfolio. Saying it leaches into the groundwater is like saying "dams break and destroy towns". Yeah, it does happen I guess, but not often. And we've got lots of systems to prevent it.
Firstly, the containers are known to develop leaks over decades. Secondly, there are accidents on site every year, causing tritium leaks if not also uranium. There is also a baseline level of tritium leakage that's considered normal, but it isn't actually normal for the fishes in the river.
> I prefer to assume we're comparing competent operators
Please see the list of leakage incidents at each nuclear power plant. There is one almost every year at almost every site. The local environment pays the price for it. If they were competent, these events wouldn't happen.
None of this is an issue with solar, for example. The radius of the possible damage is minuscule.
Nuclear waste only slowly leaks if its stored improperly. The better option is to use it, reacted fuel is still super useful stuff. N breeder reactors have been developed to decrease fuel requirements by a factor of 100. Instead of one egg of "spent fuel per person... one egg per 100!
Comparing it with coal is 100% disingenuous. Coal is never an option going forward.