The economic advantage of SMRs is that when you make reactors in a location, the 1st is always more expensive than any following reactors. Just a reality of construction, permits, designs, etc. So if you have 4 reactors in one place, that’s pretty nice. They also have the advantage of being able to turn one off for maintenance and then having 2, 3, 4 other reactors in the same vicinity that can pick up the slack for the duration.
As for waste, yeah it’s the same problem. But it’s important to note that the volume of material is not that big. The entire volume produced by all us nuke energy ever takes up a football field stacked 10 yards high. All told, that’s a smaller problem than I ever thought.
I’m not a big nuclear advocate, I’m pretty mid on it. This is where I got all of the above information, an interview with the head of the US DOE loan program https://www.volts.wtf/p/nuclear-perhaps?amp%3Butm_medium=web
So energy remaining and radioactivity are separate. The isotope that it becomes has a decently long half life, but it might only be a few protons or neutrons away from something really radioactive.
I do believe that the fuel rods count towards that pile of waste. I think the US has laws or rules that make it hard or impossible to recycle these back into the good stuff, but it’s very doable. France does it to a high degree.