The idea was to also have nuclear powered merchant ships and passenger ships. As the article comments:
> Unlike the commercial shipping industry, the military did embrace nuclear. Of the estimated 700 nuclear-powered vessels which have seen service over the years, including the 200 currently at sea, the majority are military ships and submarines. Dedicated Russian ice-breaking ships are the only civilian examples.
http://en.wikipedia.org/wiki/Nuclear-powered_icebreaker