Well, you could put the containment completely underground, but you'd need to run your coolant of choice up to the surface (and you'd need air intakes for human

Well, you could put the containment completely underground, but you'd need to run your coolant of choice up to the surface (and you'd need air intakes for humans etc). You wouldn't need to with once-through water cooling using a large body of water, a river, or the ocean, but that's not allowed anymore. Note that reactor vessels themselves are sometimes at least partially underground in a reinforced concrete pit in the containment.