Lots actually, the way it is fueled, completely different (as in you don't re-fuel it you replace it) so all of the re-fueling infrastructure is not needed. They replace water (low pressure or high pressure) with helium which gives them two benefits, one it carries more heat and two it doesn't become a high explosive[1] when exposed to extreme temperature. Another benefit of helium is that if it leaks from the system, it carries no fission byproducts(like Cesium) in solution and has no radioactive isotopes with half lives of more than a second. 6-Helium has a half life of .8 seconds and emits a beta particle.

So pretty much all different :-)

Most nuclear plants operate at lower steam temperatures than coal, because thermal efficiency isn't so critical and lower temperatures are less wear on the pipes and turbines.

WRT cost: Nuclear plants could be cheaper. Because, for instance, coal plants require scrubbers to meet particulate emissions rules, which are very expensive to install and operate. And coal is expensive: mining, transporation, cleaning.