If China gets fusion energy first they will obtain unimaginable power, hell the same applies to the US. While stopping climate change would be great I also fear for what we might put in its place.
You don't get unimaginable power from a fusion plant.
Fusion plants don't generate unlimited energy. You'd need to build several of them to even power your country for "free". Energy is usually 20% of GDP -- probably higher in China -- so you'd get a ~20% GDP growth. It would take time to build these plants, and they're unlikely to have a 100% ROI, meaning that they'd still come at some cost.
Yes, it would be huge. Probably a one-time 20% boost in GDP. Maybe a percentage point continually for having cleaner air. Maybe a little more if they could hypothetically commercialize this for other countries.
It doesn't matter whether it's unlimited or not if it's practically free. Do you know how many manufacturing processes could become practical and how much research could be done given inexpensive energy?
The claims that it's going to be wonderful don't get subject to this sort of scrutiny, but whatever...
There are multiple reasons to think fusion can't win. The simplest is that fusion is a thermal power technology. Heat is produced, which heats a working fluid, which drives turbines, which makes power. ALL thermal power technologies are struggling now, particularly "external combustion" ones that transmit the heat into the working fluid through heat exchangers or boilers. Nuclear fission, coal, geothermal, solar thermal: all of them are having trouble competing. Only combustion turbines are doing ok (internal combustion, avoiding expensive heat transfer stages). Even if the fusion heat source were free, a fusion power plant would not be competitive. And the expensive non-nuclear part is mature technology in which not a lot of improvement can be expected.
But beyond that, there's good reason to think fusion would be more expensive than the other thermal power sources. Compare the volumetric thermal power density of ITER vs. a PWR primary reactor vessel: ITER is worse by about a factor of 400 (0.05 MW/m^3 vs. 20 MW/m^3). Smaller concepts, like ARC or Lockheed's are better (about 0.5 MW/m^3) but still far inferior to fission. A fusion reactor would be far larger, and far more complex, than a fission reactor. Fuel is not a large part of the cost of fission power, btw.
This failure to be competitive is not an accident. It follows from the square-cube law: a fusion reactor must transmit its output through the surface of the reactor vessel, while fission and coal can transfer heat to the working fluid through the surface of thin fuel rods or boiler tubes. This generic handicap, which is independent of anything to do with plasma physics, has been known for nearly four decades, if not longer.
There are other showstoppers (materials, reliability/maintainability, tritium breeding) but those two are enough.
The only hope fusion has, and it's a thin one, is advanced fuels that would allow direct conversion, skipping the thermal stage entirely. But all advanced fuel concepts will still produce a large fraction of energy in photons, which will strike surfaces and be thermalized. And they either depend on 3He, which is science fictional in its sources (moon mining?!), or H-11B, which is likely impossibly difficult at the plasma physics level (and 2000x less reactive than DT, best case.) And even advanced "aneutronic" fuels will leave the reactor too radioactive for hands-on maintenance, due to unavoidable side reactions. Given how large and complex a fusion reactor would be, that is also a showstopper.
If anyone demonstrates a 'working' (that is, economical) tokamak, that will swiftly prompt about ten other national and international projects to catch up via better funding. It's not like this is a magic ring pulled from a volcano by an elf or something; it's extremely copy-able.
having nuclear fusion available will be good in the long term because it's a clean source of energy, it won't magically give China superpowers. We already have very simple means to give anyone access to abundant energy, ordinary coal and gas plants work just fine in that regard.
This isn't a first to market huge advantage. Developing the plants is slow (many years) and the lag between super powers in cracking tech is generally only a couple of years (see space programs/nuclear energy programs)
It's playing into divisive tribal thinking, when this is literally objectively good for everyone on the planet.
They definitely aren't, because we don't read everything that gets posted here, or even close to everything. There's far too much.
If you see a post that ought to have been moderated but hasn't been, the likeliest explanation is that we didn't see it. You can help by flagging it or emailing us at hn@ycombinator.com.
Bringing that up in a thread about tokamak reactors would almost certainly break the site guideline against going on flamewar tangents.
I know that can seem arbitrary to people who have strong feelings on the topic, but it follows from HN's first principle: intellectual curiosity. We have had hundreds of generic flamewars about China. Will yet another one gratify anybody's intellectual curiosity? Of course not, because nothing new can be said about any of it. Everyone who cares about these arguments has already heard all of the lines and probably recited half of them. The only thing left to do is invent even nastier variations of the same thing. That's why flamewars get hotter as they become more predictable.
The root phenomenon is: we can have intellectual curiosity or indignation but not both. On HN, we choose curiosity. That means indignation needs to be actively contained, for the same reason that fire does.
If you want to see previous explanations about this, there are tons:
Fusion plants don't generate unlimited energy. You'd need to build several of them to even power your country for "free". Energy is usually 20% of GDP -- probably higher in China -- so you'd get a ~20% GDP growth. It would take time to build these plants, and they're unlikely to have a 100% ROI, meaning that they'd still come at some cost.
Yes, it would be huge. Probably a one-time 20% boost in GDP. Maybe a percentage point continually for having cleaner air. Maybe a little more if they could hypothetically commercialize this for other countries.