A nuclear powered cruise ship would be efficient and it would make sense to me. However, there are many people that would NOT cruise on a nuclear powered cruise ship.
I guess for now, we just have to open our wallets a little wider.
Carnival Liberty New Year's Eve 2007
Liberty of the Seas 5/2008+11/2009
Allure 1/16/ 2011
Vision OTS 2-14-2015
Freedom OTS 3/6/16