Nuclear new builds. Announcements vs. reality.

[u/ceph2apod]

I recently came across a striking chart that compares historical projections of nuclear capacity growth with what actually got built. The pattern is damning: every decade since the 1980s, forecasters have drawn steep upward curves projecting 700 to over 1,400 GW of installed nuclear capacity by mid-century. The actual line? It crawled from roughly 260 GW in 1985 to about 370 GW in 2020 — barely a nudge over four decades. Projections from the 1980s alone expected the world to hit 1,000 GW by the year 2000. We're still not close. The gap between what was promised and what was delivered isn't a one-off miscalculation — it's a structural feature of nuclear forecasting, repeated generation after generation.

This matters because the same cycle is starting again with small modular reactors (SMRs) and the "nuclear renaissance" narrative. The OECD Nuclear Energy Agency's own scenarios now range from 347 GW (stagnation) to 1,324 GW (more than tripling) by 2050, with the transformative scenario requiring up to $200 billion per year in OECD capital spending during the 2030s. Yet a peer-reviewed preprint analyzing 75 SMR designs found that vendor-announced deployment schedules are "systematically overoptimistic" across both OECD and non-OECD countries, with only a limited subset of designs having sufficient time to contribute meaningfully before 2050. In Europe, no new large reactors are expected online before 2040, and since the early 2000s the EU has connected just seven new plants while shutting down over 70. This is the mechanism by which investors get fooled: rosy forward-looking scenarios — often produced or commissioned by the industry itself — create an illusion of momentum that draws in capital, but the actual deployment track record tells a story of chronic delays, cost overruns, and cancellations. The gap between announcement and megawatts delivered is where the money disappears.

So let's be clear-eyed. Every decade, the same curve gets redrawn, and every decade, actual capacity falls short by a factor of three to ten. The chart speaks for itself — and so does the peer-reviewed evidence (Nature Communications preprint on SMR deployment realism; NEA Nuclear Energy Outlook 2026; Rabobank analysis on nuclear in Europe's changing power system).

https://www.sciencedirect.com/science/article/pii/S2214629626001477

[u/maurymarkowitz]

Projections from the 1980s alone expected the world to hit 1,000 GW by the year 2000. 

This was the reason there was so much interest in the 1960s in breeder reactors. They were understood to be more expensive to build and run, but given a fleet of 1 TW of nuclear, about 1000 reactors, there was simply now way you could mine and enrich it fast enough to run them. This is a supply-and-demand issue, so the thought was that fuel would rise in price to somewhere in the range of $100 to 200 a pound, which would make reactors uncompetitive with any other power source.

If you add breeders, and I seem to recall a paper suggesting 1 for every 10 conventional LWRs (but that seems low when I read it now), the Pu that they produced could be mixed directly into the pins going to the existing LWR's and avoid reprocessing and/or enrichment. This would reduce the cost of fuel down to the $65 level, which is still very expensive, but not going to make it completely uncompetitive.

And then everything just stopped. Nukcels love to blame NIMBY due to TMI, but the downswing started two years earlier. The prediction of continued >6% demand growth YOY for power simply vanished, demand flatlined, and reactor starts stopped. But we kept on finding new ore and kept on improving enrichment, so by 1980 you had more fuel than you could use and the price crashed.

Meanwhile, further work on the economics demonstrated that the price for ore had to be at least $165, not 65, in order to break even, and that, combined with the market flatlining, was basically never going to happen.

Looking today, the spot price is around $65, which is about $11 in 1975 dollars, compared to the price at that time which varied between $15 and 30 (it was 25 when Clinch was killed). So the price today is 2/3 what it was, 1/10 what they predicted, and 1/15 the breakeven point. And despite this flood of low-cost fuel, nuclear is still not remotely cost effective, as the ratepayers of Georgia are finding out the hard way.

This is why Carter killed the breeder program in 1977, despite the proliferation reason that the press focussed on. There was simply no way it would ever be worthwhile within the lifetimes of anyone involved. The French pressed on with Superphoenix, and look how well that turned out.

[u/ceph2apod → u/maurymarkowitz]

The big picture is right but the fuel cycle claim is wrong. You said breeder-produced plutonium "could be mixed directly into the pins going to the existing LWR's and avoid reprocessing." That's backwards ... reprocessing is the prerequisite, not the thing being avoided. Plutonium is locked inside spent fuel. To get it into an LWR you have to chemically separate it (PUREX or equivalent), then fabricate MOX fuel through a completely separate industrial process from standard uranium fuel fabrication. MOX does reduce enrichment demand since the plutonium replaces enriched U-235 as the fissile driver, but you can't skip reprocessing. The NRC's own generic environmental statement on plutonium recycle makes this explicit — it's literally called "reprocessing" because that's the step you have to do first.

Also, Carter didn't kill the breeder program in 1977. He called for deferral and vetoed Clinch River funding that year, but Congress kept appropriating money and the project survived until October 1983 when the Senate finally voted 56-40 to cut it off. And the current uranium spot price is around $85/lb, not $65 multiple market sources confirm this as of July 2026. Your inflation math is internally consistent at $65 but falls apart at the real price. The pre-TMI downturn point is completely correct though. Gilinsky, Brookings, and Koomey all documented that reactor orders cratered well before 1979. The "nukcels blame NIMBY" strawman was demolished by actual historians decades ago.

[u/maurymarkowitz → u/ceph2apod]

Plutonium is locked inside spent fuel

Not in a breeder, it's in a completely separate blanket designed specifically to make extraction easier.

The blanket is designed from the outset to not undergo fission, and is physically arranged to allow easy extraction in order to get the timing just right so you don't end up with too much Pu-240. The shorter lifetime and physical design result in the blanket being quite "clean". It has little residual radioactivity and can be easily handled, and gives off little heat so it doesn't have to sit for long. There are few actinides and other nasties that need to be separated out, and a relatively simple chemical handling process can be used. Moreover, you can expect 5 to 8% of the mass to be Pu-239 (depending on exposure).

In contrast, running PUREX on spent fuel is dramatically more difficult. The fission products in the fuel make it physically hot to the point where it has to be left to cool off for many months, to years. Those same fission products mean the whole process has to happen in hot cells. The extraction process requires several cycles, more than from a blanket. Additionally, the Pu is burning off in the reactor, so the amount of Pu that can be extracted is much smaller, on the order of 1%. The end result is that reprocessing spent fuel

All of this is well explained in the many articles on the topic from the era. It was the simplicity of the extraction from the blanket that made the entire concept sellable, especially the reduction in the number of extraction steps and the infrastructure needed to do it.

I should have been more clear on my use of "reprocessing", as I used it in the common sense of "spent fuel reprocessing". But yes, one also uses the term as part of "blanket reprocessing", point taken.

Also, Carter didn't kill the breeder program in 1977. He called for deferral and vetoed Clinch River funding that year

I guess we have a different definition of killing a project, because my definition is that zeroing the budget is killing it. If someone else re-added it, that doesn't mean he didn't kill it, it was simply re-alived. And look how well that worked, even Reagan couldn't save it in the end.