Another poster already mentioned that transuranics and other such byproducts tend to be very dense, so a swimming pool can in fact hold tens of thousands of tons of spent fuel. Also, ‘nuclear waste’ is a generic catch-all term that includes less radioactive material, compared to ‘spent fuel’ which is just the really ‘high-grade’ material.

The part about not needing enrichment is worth discussing, but we do have solutions to that already. There are entire classes of reactors dedicated to not producing weapons byproducts or needing enrichment using the same processes capable of generating weapons-grade material. The reason we see reactors that can make these materials so often is because many of the early reactor designs (many still in use today) were explicitly selected for use by the US government during the early days for their dual-use ability to make plutonium for nuclear weapons. Examples of proliferation-safe designs include molten salts and integral fast reactors, but there’s an engineering experience chicken-and-egg problem - they don’t get built very often because we don’t have experience building them. A new design like this will face the same challenges.