We were still learning about flaws and failure modes of nuclear reactors. Designs kept evolving to try to address these. We never got to the passenger airliner model where we had systematically eliminated nearly every failure mode and could produce this on an assembly line.

> We could have standardized the old reactors too.

Yes, but the potential market for GW-size reactors is fairly limited.

Now, whether the market for any of these SMR reactors is large enough that any of them will be able to see any of these supposed economies of scale is a big question.

Floating nuclear plants next to a city sound like a recipe for disaster

> France is still shutting down its plants because the rivers are too warm in the summer.

That's because French nuclear power plants are designed to be directly cooled by river water instead of using cooling towers.

The biggest nuclear power plant in the US (Palo Verde Generating Station in Arizona) is cooled by evaporating the treated wastewater, in the desert.

You can’t standardize manufacturing of multi billion dollar facilities. Economies of scale just don’t work that way. Even residential housing has the same problem. There’s too much variation in on-site construction.

It's a great story: in theory you can produce modular components of a full scale nuclear power plant in a controlled environment. In theory.

In practice the production line wasn't as controlled as it needed to be and ended up delivering modules that needed significant rework. That caused modules to be delivered and ready out of order. In other words they bought a lot of project management complexity that was hidden behind the theory of modularity.

SMRs are turning out to be even more expensive than conventional nuclear power plants, which are so expensive compared to renewables that even without a risk premium they are uncompetitive.

Vogtle, Hinkley Point C- are all one off constructions and have very expensive regulatory compliance requirements

AP1000 (reactor as Vogtle 3/4) in Taishan is estimated to cost $4M-6M /MW compared to $15M/MW+ at Vogtle. if Chinese safety standards seem lax, South Korea does regularly reactors at $4-6M/MW range.

Even Flameville 3 in France was significantly cheaper than Hinkley point C (same reactor type), which infamously required some quite ineffective Fish speakers. The EPR2 series (6 reactors) in France is expected to cost considerably less than Flameville did.

Key to cheap nuclear - SMR or otherwise is regular construction. SMR makes regular construction more likely as each plant is not a $10-20B+ capex that is a tough sell to tax payers particularly when it inevitably overruns, SMR also potentially have a bit less regulatory hoops to jump through due to their smaller size.

That's another interesting theory, but Wright's law doesn't mitigate many other disadvantages of SMRs: the need for multi site security; the need for on-site technicians at more sites; the need to build grid hook up to more locations, etc. There's a reason reactors grew to a certain size, no smaller and no bigger. Ignoring that lesson has a high price.