I’m trying to figure just how much volume of material we are talking about here... Enriched U is in metallic form, right? And not so far away from Pb in density? IIRC a ton of Pb is a cube about 15 to 18 or so inches on a side. So we’re looking for about fifty times that... Maybe the size of a cord of firewood? About 4x4x8. That sound about right?
Highly-enriched uranium is usually in metal form, often cast into billets. Density of uranium (whether 238 or 235 isotope) is about 19 g/cm³; by contrast, lead is about 11.3 g/cm³.