[dredmorbius]

There were actually several other nuclear-powered commercial ships, none of which proved economical, though there's also the small problem that about 200 major cargo ships are lost at sea every decade. That's roughly the number of all present marine nuclear propulsion systems (within a factor of two).

The others were the German Otto Hahn (https://en.wikipedia.org/wiki/Otto_Hahn_(ship)), Japanese Mutsu (https://en.wikipedia.org/wiki/Mutsu_(nuclear_ship), and the Russian Sevmorput (https://en.wikipedia.org/wiki/Sevmorput). There is also a fleet of six Soviet/Russian icebreakers, still in service, the lone regime in which nonmilitary nuclear marine propulsion has proved viable.