Aside from the real and perceived safety issues of nuclear propulsion, there is also the issue of operational availability. US submarines and aircraft carriers

Aside from the real and perceived safety issues of nuclear propulsion, there is also the issue of operational availability. US submarines and aircraft carriers spend a lot of their careers unavailable due to planned maintenance. I wonder how much of that is due to the power plant? New naval reactors are designed to last from 1/2 to the entire life of the ship without refueling. And at the end of that life, the entire reactor compartments are cut out, defueled, and stored in open-air trenches at the Hanford Reservation.[1] Regardless of whether fission reactors are fueled with HEU, LEU, or Thorium, they leave a lot of long-term things that we been as-yet unable to muster the full technological and political means to deal with. For the merchant ship application, it seems a reach to believe that the benefits of greenhouse gas reduction can be most efficiently achieved by replacing diesel engines with nuclear reactors. [1]http://www.oregon.gov/energy/nucsaf/docs/naval_nuclear_reactor_fact_sheet.pdf?ga=t http://www.oregon.gov/energy/nucsaf/docs/naval_nuclear_react...