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Comment by SoftTalker | Hacker News Reader

Yeah I think it really only works well in the central latitudes. The American South, the tropics and equatorial regions, Southern Europe, etc. that get a lot of high-angle sunlight year-round.

Otherwise you need to deal with long distance power transmission across many political jurisdictions, or local generation for night or other low-solar times. To my mind, nuclear base load with solar and batteries used for things like charging cars or demand-shifting probably makes more sense. It's really a shame that we mostly withdrew from building nuclear plants for the past three or four decades; instead we have reached the point where we have to re-learn how or recreate the tooling needed to build them and they are still too damn expensive.

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nuclear base load makes sense from a pure grid engineering PoV, which i think is why it appeals to so many HN folk. Sadly, it makes no sense economically anymore, so it will probably never be built at scale.

They quit building coal burning power plants in the US at the same time and for the same reason they quit building nukes…. The cost of the steam turbine and heat exchanges. I mean, the steam generators for a PWR are bigger than the reactor vessel, it is just insane to use hot water at high pressure to boil water at low pressure.

If nuclear is ever going to be competitive it is going to have to be some kind of reactor that runs at higher temperatures with a gas turbine power set. Could be a fast breeder or HTGR or molten salt but not water cooled. Anyway it is not a bird in the hand.

I mean yes but also there’s a lot more engineering and materials in a NPP beyond the heat exchanger part that makes it so expensive.

Ultimately though about 50% of the cost of a PWR is in the heat handling (heat exchangers and steam turbine) and the building costs to accommodate those systems. If the nuclear part was free they'd still struggle to compete -- the BWRX300 seems to get a lot of cost reduction by eliminating the pumps and heat exchangers and stuff and going to steel-concrete sandwich construction but to do better than that you have to really do something about that steam turbine.

For that matter, it's shocking how small the actual core is for FBRs. The capital cost of FBRs was long projected to be higher because traditionally you had to add a third cooling loop and some other systems but it is projected an sCO2 system today could be cheaper overall.

TIL, thanks! I didn’t realize the “routine” heat exchanger part was such a high % of cost.

It's a lot of metal! Also the first PWRs had a lot of problems with corrosion causing steam generators to fail and these had to be replaced early. Small improvements in design and better chemistry control solved this.

People are highly aware that we haven't fixed the problems construction new nuclear power plants, they are less aware that we've gotten much better at operating them on all the metrics from uptime to occupational radiation exposure.

yeah i have no objection to them apart from cost, and time to first watt.

Never said we should not have been developing the technology. But even with the old PWR designs you're not pumping carbon into the atmosphere, which is the main point.

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