Nuclear plants operate at lower temperatures and pressures and obviously require fewer refuelings. The limitations on power produced for both types of plants lie in the design and construction of the gears, shafting, thrust bearings, and supporting structure, rather than in the turbines or steam generators. High speed endurance is similar for both plants, until the conventional must slow for a few hours for refueling. The limitations on ship's speed are a product of hull design, propeller efficiency, horsepower, vibration, and thermal build up in the propulsion plant. Nuclear plants do not have a de facto advantage in any of these areas, although the smaller hull made possible by the reduction in liquid load is a factor in some designs.
Nuclear plants are far more expensive to build, maintain, operate, and dispose of.
Fuel costs are actually lower for a conventional plant, considering the costs of a refueling overhaul for a nuclear powered ship. Manning levels are higher for a nuclear plant, as are training costs. Nuclear plants require very heavy and complex foundations and shielding. This has a very significant influence on hull and machinery design. Conventional plants can be configured with many more options.