This is easy to solve. Just launch the waste into Space. A typical large reactor produces 25-30 tonnes of used fuel per year. That’ll take one space trip for Falcon 9 to launch it into Space on a trajectory to nowhere. It’ll destroy itself over millions of years or immediately. Either I make no sense at all or why else has no one tried it yet?
Falcon 9 carries that to Low Earth Orbit. You do not want the waste hanging around there. To get it out of earth's orbit, F9 can do 8 tons.
That's 3 - 4 flights per year per reactor, so about $250m per year. Plus Falcon 9 did 60 flights this year, so this even capacity-wise this would only be enough for 20 reactors worldwide.
Plus like other commenters mentioned, a launch failure would be catastrophic.
1) Because storing spent nuclear fuel on earth isn't actually hard, it is just brought up anytime people talk about nuclear because it's the obvious thing to talk about.
2) Rocket fleets have a ~97% success rate (e.g. see Vega C this week). Spreading 3% of the radioactive material globally isn't a great idea.