Lots of interesting history here, but most relevant was that regulatory and process changes starting in the 80's made it increasingly expensive to build reactors. As a result, reactor construction companies (notably Westinghouse) went bankrupt and no entity was willing to take financial risk to build new reactors. Western Europe is a different story, where political parties aggressively shutdown healthy nuclear plants and passed laws preventing new nuclear.

Much of this regulation and process overhead is now being rolled back in the US (by both political parties) and Europe is slowly coming around to allowing new nuclear. NuScale is one of many next gen companies (I hope they're all successful), but the traditional large reactors are also great and can be built cost effectively.

It's just experience in most cases. We don't build enough so the management and project structures and experience to do it never get a chance to be efficient.

The right thing to do with something like the Vogtle plant for example would be to keep building them since you've just paid some very expensive costs learning what causes delays, but the knowledge of what gets the plant built - because it was built - is still there and fresh.

This is the idea behind the “small modular” part of SMR. Current nuclear projects are huge, largely bespoke efforts that require a bunch of contract firms working together on different parts of the project. The idea of SMR is to push most of the necessary parts one after another from a factory. The best analogy I’ve heard for this is comparing how the Japanese built planes in WWII (in small batches done by craftsmen) to how the US did (with an assembly line following a documented process). I buy the conceptual argument, but there are a lot of details to work out.

One radical answer that question which is often neglected for the facile "regulations" explanation is that we quit building coal burning power plants at the same time we quit building nuclear plants because the steam turbine and heat exchanger cost too much compared to natural gas plants.

The timing undermines this theory. The US added one nuclear reactor to the grid in 1996 then zero until 2016 (sort by first grid connection date here):

https://pris.iaea.org/PRIS/CountryStatistics/CountryDetails....

The US built an additional 58 coal generating units between 1995 and 2009 (see section "Age comparison of coal plants"):

https://www.gem.wiki/Existing_U.S._Coal_Plants

Combined cycle natural gas units were already cheaper to build in 1995, but the gradually rising natural gas prices over the next ~12 years meant that coal could still compete on cost for electricity generation. The cheap fuel for coal units counterbalanced the slower, more expensive construction process. It wasn't until fracked natural gas drove fuel prices down that coal unit construction ended in the US.

A lot of the natural gas plants are combined cycle, which includes a steam Rankine bottoming cycle.

I think "promises" is the key word there. Data centre's want power, as you say, but they want it now, not 15 years from now.

So yes, when SMR's are "off the shelf" (aka from "order" to producing) , including permitting, construction etc, within a couple years then they are appealing.

I don't think we're quite there yet.

There is necessity with baseload plants: they have to be run at high capacity factor or else their economics go all to hell. This is especially true of nuclear where capex dominates. So describing something as "baseload" is actually describing a defect: it's a generation technology that cannot be practically dispatched.

Of course electricity at night is highly desirable. But there are no economic incentives to build it.

From a purely financial point of view, base load is not appealing. Whereas cheap solar is appealing. If I have a billion$ to invest, I know which one I'm choosing. I'm maximizing return, not "societal good". Which is why govt is best placed to build base load, since they optimize for societal good, not profit.

To make base load appealing to investors we need expensive power at night. But that's countered by local battery storage.

To be clear, this is not a "what we need" argument. It's a capital argument. Private Power suppliers chase profit, and there's more profit in daytime power than nighttime power.

> Storage is extremely expensive

Define "expensive". Over what timescale? Have you seen https://ember-energy.org/latest-insights/solar-electricity-e...

"Achieving 97% of the way to 24/365 solar in very sunny regions is now affordable at as low as $104/MWh, cheaper than coal and nuclear and 22% less than a year earlier."

This is right now, July 2025. The costs of batteries continue to fall. How much cheaper will batteries be by the time we start churning out SMRs fast and cheap?

By all means keep beavering away at nuclear. Its time will come one day. But I won't hold my breath for it to solve the climate problem in the next 10 years.

Are you so sure that storage is so expensive? It’s been coming down the cost curve extremely quickly, such that opinions formed even an year ago are severely outdated, and it’s now solar+storage that’s being favorably compared to replacing nat gas plants, not just solar itself.

> Solar is very, very cheap and almost totally worthless without storage.

For say an AI training-oriented data center, you could scale down the power usage when supply is limited. You could change power limits on the CPU/GPUs, put the machines in sleep mode or powered off entirely. So the required storage would just be a slightly bigger UPS.

Not sure if the economics works out, but at least technically it's possible as it's more flexible than user-based loads.

Solar benefits from storage yes but it's not at all worthless even without it.

If your solar panels generate 10 TWh per year, you have 10 TWh unused hydro, gas, even oil and coal that is stored instead of spent. You have saved the planet from megatons of CO2 emissions even if you have no new green storage.

Solar is already adding the equivalent of several nuclear power plants worth of new electricity every few months. Getting another month's worth of electricity delivered 10 years from now is not much of a bridge.

I think solar and storage just needs every other worse idea to stay out of the way and things will be fine.

> The cost of nuke energy is not because the technology is complex or because resources are scarce. It's because we have very, very burdensome regulations around nuclear reactors (for good reason!)

So its easy, at least if it wasn't for all that burdensome regulation. But also the burdensome regulations is actually good, presumably because it's hard to get right.

This sounds like nonsense to me. If the regulation is good, that would usually be because a thing is hard to make work in a liberal society, usually for some misaligned incentive reasons. In that case the regulation isn't "burdensome" but necessary to counteract the failure of the market.

> Storage is extremely expensive.

No.

> than the pollution we've had waiting for an idealized answer to arrive.

As I'm fond of saying, environmentalists didn't kill nuclear. I'm not denying they had motive. But they lacked means. They can't stop anything else they've set their minds to: fossil fuels, automobiles, deforestation, industrial livestock farming. Even whaling is alive ffs.

No, there was another party with both motive (competition) and means (lots of cash and political influence) to do the deed: the fossil fuel industry. And nuclear didn't help itself with accidents (and ensuing costly clean ups, one of which helped take down the Soviet Union), and budget overruns even when things went smoothly. Both found a convenient fall guy: the green movement.

Tl;dr nuclear hasn't grown because of money. It cost too much, and the competition had the cash to slander its reputation.

> It could be dumped in the ocean

FFS no. This is the reason environmentalists don't trust the nuclear industry.

Nuclear proliferation.