As noted elsewhere, these don't create the same kind of spent fuel as a PWR. So that helps.
But also, the people who designed the PWRs didn't just say "and then we'll make shitloads of unmanageable waste lol!" Up until the Carter Administration, we ran a system called "reprocessing" that essentially shredded and dissolved the old fuel rods, isolated the metals chemically, and packed out separately.
France does this. Finland does this. Japan does this. Their waste concerns are negligible compared to ours.
Meanwhile Carter, bless his heart, determined that reprocessing was a proliferation risk, and shut down the US industry, saying "y'all will figure out a way to dispose of these things".
So now we are using circular saws to hack these things apart, cramming them into barrels stuffed with kitty litter (you read that right), and hoping that nothing will happen to the barrels for 50 million years?
Long-term waste disposal became an impossible problem to solve in the US because our one and only allegedly nuclear-savvy president made the solution to the problem illegal. It became one immediately, and has never stopped being one.