> Perhaps the newer smaller reactor plants proposed atm might not quite the same level of trouble decommissioning them.

Not as much material per single decommissioned site - but in total, simply to laws of scale, a lot more.

For the US this doesn't matter anyway, the US has ample amounts of geologically stable desert areas where they can just bury anything from UFOs to nuclear waste without anyone being bothered by it or it posing a danger to its surroundings, but Europe... outside of the Nordic countries with their granite rock formations, good luck finding a suitable site that doesn't risk contaminating the groundwater that is the source of drinking water for millions of people (see e.g. the Asse storage site and its issues).