Every time we built a nuke they changed to rules and regulations, so no two were alike and more expensive. In France they settled on a design and built them all the same which was much cheaper.
The Westinghouse Pressurized Water Reactor system was reasonably safe in that the radioactive water transfers the heat in a heat exchanger to the water that became steam and drove the turbines.
GE came out with the cheaper Boiling Water Reactor System where the radioactive steam drove the turbines making the machinery and turbine hall hot. In order to overhaul the turbines, the radioactive parts would be shipped back to GE for machining.
The real problem with the nukes is how to dispose of the spent fuel, but all they have to do is build a wall out of it.
