“Why don’t they just use the engineering blue prints of successful nuclear power plants with minor modifications for existing geological conditions to build new one?”
It’s a good idea, but reality is more complicated. For example the Turkey Point water pumps would be a model that was discontinued 30 years ago.
You need a current model of pumps, but that then requires redoing the piping design. That requires a new set of valves. All elements require a new set of sensors.
Repeat 1000 times for all the different components, and you have now designed an entire new plant.
Which shows the utter stupidity of “.New!New!New!”
The constant drunbeat to replace proven,reliable,working things with “new,improved?” AND foolishly discarding the ability(plans and tools) to make the old reliable thing.
Did the French choose one design and build many identical nuclear plants or did they build every plant unique as we apparently did?