At a cost which could generate ~10 billion watts of very low CO2 electricity for decades if invested in renewables.

Also remember that large parts of a nuclear plant is replaced over its operational life. Control systems, steam generators, turbines, generators, tubing, valves etc.

What stays is the outer shell and pressure vessel. A nuclear plant doesn't just "work" for 60 years. And there's no trouble designing renewables with a 60 year lifespan.

We just don't do it because spending money on getting their expected operational lifetimes from decades to 60+ years is betting on extremely uncertain future returns.

With waste with half lifes in the tens of thousands of years sitting in metal casks which cant last 1,000 years.