Spent fuel to this day. If they decommissioned a plant on the day they crucified Jesus, we would still be storing that spent fuel. That’s a long ass time. We had the fall of an empire, the dark ages, the renaissance, the enlightenment, global colonization, a whole bunch of wars due to that along with a few genocides, the Industrial Revolution, a couple of world wars, a few more genocides, and the housing for that spent would have to hold through all of that. And people would have to be paying attention to it.

I recognize nuclear power’s advantages and have always been a proponent of its proliferation, but it’s incorrect to call it clean. You and I are unlikely to have to deal with it, but humans eventually will.