Modern Generation III/III+ reactor designs have actually made this "chunkiness" worse; there's no modern reactor design under 500 MWe that's certified in the US, Canada, Japan, South Korea, or the EU. Designs in that lower power range were built decades ago, and a few still run, but now it's big-or-nothing. AP1000 and EPR are 1117 and 1600 MWe, respectively, and all projects using them are behind schedule/over budget. And since these large projects are leading to such poor outcomes for involved companies, it will be difficult to get follow-on orders that will benefit from the hard earned lessons of their initial builds.

Even if all the technical problems are solved and fusion proves capable of producing net electricity, fusion power risks hitting this same too-big-to-build problem afflicting fission if it can't scale down. If the only approaches that work are enormous tokamaks with an entry level price of $10-billion-or-more, then they'll be engineering marvels that hardly anyone builds. Maybe they'll someday supply 10% of China's electricity.

Fusion hydrogen requires heavy isotopes, namely tritium, to generate sufficient reactions. This generates s lot of free neutrons however, enough that they will tend to destroy what container they're in. This is a significant, possibly commercially insurmountable, engineering problem.

Helium-3 is one alternative but is super rare on Earth ( even the heavier Helium-4 escapes the Earth's gravity once it reaches the atmosphere (so party balloons are consuming an irreplaceable resource thanks to an effective subsidy from Congress who narrowmindedly decided to offload the Strategic Helium Reserve at submarket rates).

People like to bandy about phrases like "free energy" when it comes to fusion. Well, free fuel and free energy aren't the same thing. A plant has a capex and running costs, a finite lifetime and a power output. Put those numbers together and you have a base energy cost even with free and essentially limitless fuel.

The article talks about producing tritium from lithium. Great. The demand for batteries is already going to stretch the worlds lithium supply so that's another advance we need.

Honestly I feel ITER is such a big boondoggle that its cannibalizing pretty much all other fragments of research in fusion. for reference even based on tokamak design MIT ARC is uses much higher T REBCO superconductor based magnets that ITER cannot even adopt. which do you think has a better chance of success? besides that there are multiple other efforts like German stellarator, FRC based design by trialpha and even the opensource focus fusion. IMO its much better to spread the resources into these efforts rather than dumping a bunch of money into monstrosity like ITER and going back into the lap of fossils for next 2 decades.

thinking about [lack of] fusion funding really pisses me off.

/end-rant

Most of the issues with current fission are political ("spent" fuel can be reprocessed) and economic (these beasts are insanely expensive to build and operate safely) and we haven't even touched MSR's and Thorium. I get fusion would be beautiful, but it has its problems too (heavy neutron bombardment will eventually turn the reactor into a pile of hot nuclear waste - or, at best, MSR fuel) and we may need to face the simple fact our technology isn't up to that challenge just yet.

Although stellarators may offer some shortcuts.

Maybe we'll need fusion for multi-generation starships supposed to operate for many centuries on a closed loop system, but that need seems a bit too far into the future for us to concern ourselves too much with it. Solar should be fine up to Mars and compact fission should be enough up to the Oort cloud.

If they took even 1/10th of the money and spread it around some of the more promising, smaller, non-tokamak, scrappier fusion projects like tri-alpha, polywell, or the Lockheed skunkworks one that actually have a plausible path to power generation I think that the money would make a better impact. Even next gen fission would be a better investment. India and China are doing very nice things with thorium these days... Too bad they'll never turn off the pork faucet until forced.

(</sarcasm> I've been hearing how fusion reactors are "just around the corner" since I was a teenager, at least 40 years now.)

Found the problem.

[1] https://en.wikipedia.org/wiki/Wendelstein_7-X

EDIT: originally I wrote 195 countries, which is BS of course :)

The usual comparison here is that one laptop battery's worth of Lithium is enough to provide an individual's energy need for life. So at current consumption rates, there is enough Li available through traditional mining to supply the world with one thousand years of energy, and closer to one million years' worth if we recover it from seawater.

I prefer to think of this as "providing incentives necessary to exploit the resources of Jupiter and Saturn."

Maybe when the history of space settlement is written it will have a chapter on the contribution party balloons and political squandering of strategic reserve had on resource prices...

Can't imagine that this sort of process will use anywhere near as much lithium as the battery industry. It's fusion, after all.

Another aneutronic reaction is proton-boron. Boron isn't as abundant as deuterium but there's still enough on Earth to last tens of thousands of years. (The reaction use B11, which is 80% of natural boron.) pB11 fusion is especially difficult but several startups are trying it; the biggest is Tri Alpha, with about $500M invested. They attained stable plasma a year ago and just completed a larger reactor.

With D-T, the easiest reaction, there may be ways to engineer around the neutron issue. General Fusion does fusion pulses in the middle of a vat of molten lead and lithium. MIT's ARC design is more conservative, with a compact tokamak and modular construction. The inner wall is 3D-printed and replaced annually; they say after a couple decades the radioactivity will have decayed enough for cheap disposal. They surround the core with a blanket of molten FLiBe salt as coolant and breeding blanket.

Plus, won't nearly all neutrons be incident on lithium to breed tritium in a final reactor anyway? And you don't need very much lithium anyway so there shouldn't be a concern over lithium availability.

I also don't understand why you're complaining about the loss of super-rare helium isotopes, but think that we're going to run out of Lithium due to this process, which is orders of magnitude more common.

The bottom line is that even a rudimentary fusion power system can capture 10x whatever energy you put in place. This blows away any other form of power generation no matter what measure you go by. Which is why it's still getting research money even if the result may be decades away.

Well... If you run a fusion reactor for long enough, you can dismantle it and use the scrap as fuel for much easier to build fission ones. ;-)

I agree that fusion is severely underfunded, and that it is dangerous for us to put all our eggs in the Tokamak basket. And this article is pretty strange for its fixation on DEMO which at this point might as well be made of unicorn horns. But ITER was proposed and is supported by a huge number of scientists for a good reason: it's the best way for us to hit a goal that fusion science has been dreaming of for 50 years, that is key to understanding and designing real fusion reactors.

It's great to have a diverse approach in the R&D phase, but sooner or later you're going to have to build a viable machine to study it, and that's when you run into the problem of scale. Confining a plasma of hundreds of millions of Kelvin is no joke even with superconducting magnets, so to get any sort of useful confinement it will have to be at least as big as ITER. And since neither individual governments nor the private sector want to unilaterally fund something so big without a guaranteed ROI, if we want the progress then there's really no way around this stepping stone of a huge, expensive, politically-charged multinational project.

You can see the first few faint traces of it today with complaints about killing birds and such.

That's a valid concern. Probably in 37 years, we'll all be riding in self-driving electric buggies that recharge in 10 minutes from stored solar power.

Lockheed-Martin[1] is working on a compact fusion design that some day might fit on a truck yet power a city. It might keep a C-130 plane aloft for a year, or keep an aircraft carrier at sea for multiple years. It might power a spacecraft to Mars, shortening the trip from six months to one month.

There is a need for a compact, concentrated, continuously generating power plant at least for these kinds of specialized applications. Whether it will still make financial sense by the time it's actually working is another question. Perhaps the main use case will be military, though the idea of an airship that can stay aloft for months or years is rather appealing -- given enough power, you could put a city in the sky.

1. http://www.lockheedmartin.com/us/products/compact-fusion.htm...

also there are other uses that can make really plentiful rocketfuel esp for exploration outside of the inner solar system.

Fission could power us for 100-200 years at current consumption rates - substantially less if consumption continues to grow. It's not time to panic yet, but we can't afford not to be doing fusion research.

That said, ITER is not a good approach. Way too expensive, not scalable. It is good as a research project, but we need scalable and cheaper solutions.

No fusion reactor so far has achieved ignition, that is, producing more energy than we put in. Are you suggesting we just assume one would work without building one?

ITER isn't meant to be commercially viable, it's the step in between something like Wendelstein/JET and a commercializable plant. If all goes well the plan is to follow up with DEMO which will be a commercial design that can be replicated for actual power plants.

Science and engineering cost money, and investment in fusion has consistently been substantially below what scientists estimated as necessary. There's a whole bunch of materials science, control systems, and so on that needs to be done. (And while there's plenty that could probably have been done more efficiently if this wasn't a multinational project, the political reality is that no country is willing to fund such a project on its own, and everyone who contributes wants some of the contracts to go to back to their own constituents; it's not great, but politics is the art of the possible).