Standardisation will bring down the cost and time of building a powerplant.
I don’t think it is fair to compare the cost of nuclear against the cost of renewable power since they will fullfill different roles.
Renewables are great at dynamic demand, nuclear is great at base demand.
Hydro power has been shown to be quite harmful to local fish dammaging the eco system, but yes, some hydro should absolutely be used.
But renewables still can’t cut it for base demand.
I see nuclear powerplants as being a drop-in replacement for coal, oil and gas powerplats, buying us time to develop renewables further while also developing better and more efficient tech.