Yes and no. Most current fuels are Uranium or Plutonium. Both between 19 and 20 g/cm^3^. For reference, liquid water is approximately 1 g/cm^3^. Unspent fuel is a similar weight to gold.

"Spent" U~238~ is usually around 96% U~238~. If we consider the remainder a rounding error and assume all 60 tonnes is 60 million kg of U~238~. That will give us a very rough estimate of 3,000 m^3^.

Also worthy of noting are other wastes that comes from mining and refining.

There is much waste already. The "spent" waste is too radioactive to safely re-refine until later.