>Which to we ignore for coal? Cost to build a new plant? Cost to run? The decommissioning costs? (Yes we ignore the externalities, and no I don't think we should burn coal. My point is Nuclear has yet to pay its way anywhere in the world, without heavy heavy govt support - far exceeding that given to renewables)

Yes, all three. Building a nuke plant without the additional concern for outcome that we put on nuke would be relatively inexpensive. It's just concrete, pumps, and a turbine. It's a ismilar level of complexity to a coal plant. Same with running cost, same with decommissioning costs.

https://en.wikipedia.org/wiki/Kingston_Fossil_Plant_coal_fly...

Suppose we designed, operated, and budgeted every coal plant to make accidents like this a statistical impossibility. Not very unlikely, that's not the standard we hold nuke to. An impossiblity. Imagine what that would cost.

A nuke plant is concrete, pumps, fuel storage and (re)processing, a huge pressure vessel, some very complex moderator machinery, and some of the most complex industrial plant control on the planet.

Even if you ramped down the safety, it still wouldn't be cheap or simple.

"Fuel storage and reprocessing" isn't that much of the cost and a significant proportion of that is compliance costs and extreme safety measures. The pressure vessel is likewise a small minority of the cost.

Industrial control systems are fundamentally sensors, actuators and a computer. None of those is actually that expensive. Nobody should be paying a billion dollars for a valve.

Older reactors have somewhat high operating costs because they're so old, many of them were built more than half a century ago. Newer reactors often have higher costs because of the lack of scale. If you only build one or two of something you have to amortize the development costs over that many units, mistakes that require redoing work are being made for the first time, etc. Build more of them and the unit cost goes down.

Fuel storage and reprocessing isnt where vast majority of of the cost is for nuclear power, construction and decommissioning are.

These are what makes it cost 5x solar or wind.