176 points by doener 4 days ago | 41 comments
Robotbeat 19 hours ago
A useful fusion power plant needs a triple product of at least about 3e12 keV * s * m^-3.
They weren’t fusing things (at least, not much). This is a figure of merit that allows you to compare, across all the different fusion methods, how well you would be able to fuse the plasma if you were using burnable fuel such as deuterium and tritium (isotopes of hydrogen that have one or two extra neutrons).
IshKebab 17 hours ago
willis936 9 hours ago
_Microft 21 hours ago
s1artibartfast 4 days ago
https://phys.org/news/2025-06-wendelstein-nuclear-fusion.htm...
ChuckMcM 10 hours ago
lukan 7 hours ago
But there is a german fusion startup about to build a stellarator.
https://www.proximafusion.com/about
(I assumed there was some sort of cooperation with Wendelstein, but found no mentioning of such on a quick look now)
PeterUstinox 3 hours ago
mrbluecoat 2 hours ago
ipnon 11 hours ago
bawolff 4 hours ago
Is it? AI is impressive and all, but i don't think any of them have pased the Turing test, as defined by Turing (pop culture conceptions of the Turing test are usually much weaker than what the paper actually proposes), although i'd be happy to be proven wrong.
WillAdams 23 minutes ago
akoboldfrying 1 hour ago
I've just read the 1950 paper "Computing Machinery and Intelligence" [1], in which Turing proposes his "Imitation Game" (what's now known as a "Turing Test"), and I think your claim is very misleading.
The "Imitation Game" proposed in the paper is a test that involves one human examiner and two examinees, one being a human and the other a computer, both of which are trying to persuade the examiner that they are the real human; the examiner is charged with deciding which is which. The popular understanding of "Turing Test" involves a human examiner and just one examinee, which is either a human or a computer, and the test is to see whether the examiner can tell.
These are not identical tests -- but if both the real human examinee and the human examiner in Turing's original test are rational (trying to maximise their success rate), and each have the same expectations for how real humans behave, then the examiner would give the same answer for both forms of the test.
Aside: The bulk of this 28-page paper anticipates possible objections to his "Imitation Game" as a worthwhile alternative to the original question "Can machines think?", including a theological argument and an argument based on the existence of extra-sensory perception (ESP), which he takes seriously as it was apparently strongly supported by experimental data at that time. It also cites Helen Keller as an example of how learning can be achieved through any mechanism that permits bidirectional communication between teacher and student, and on p. 457 anticipates reinforcement learning:
> We normally associate punishments and rewards with the teaching process. Some simple child-machines can be constructed or programmed on this sort of principle. The machine has to be so constructed that events which shortly preceded the occurrence of a punishment-signal are unlikely to be repeated, whereas a reward-signal increased the probability of repetition of the events which led up to it.
[1]: https://archive.org/details/MIND--COMPUTING-MACHINERY-AND-IN...
ahoka 5 hours ago
ojosilva 3 hours ago
Imagining a future: with a ~3% growth, so let's say fusion is deployed and everything is electric in the next few years (not happening that fast though), with AI data-centers everywhere so individual-level AI runs (say "Her"'s movie personal OS-level stuff) per human and we reach the out-of-my-buttocks figure of 500 TWh/year in 10 years time, which is crazy shit ... well, that would not "boil the world"!
The Sun delivers ~170,000 TWh per year. So 500 TWh still would not be that significant, and within the Sun's yearly delivery fluctuations.
The problem with energy generation today is that it's releasing gases, and these gases are disrupting the planet’s energy balance - especially how Earth gets rid of the massive energy it receives from the Sun. We do need to restore the balance between what comes in and what goes back out - fusion can help tackle that problem specifically, so it's beneficial overall even if it eventually adds a fractional percentage to the overall planetary energy bill.
I picture that fusion would be a complementary source, not the only one, and, once/if deployed, would help close some of key the loopholes that prevent solar (and other renewables) from being deployed 100%.
thechao 3 hours ago
K0balt 4 hours ago
WillAdams 21 minutes ago
Why not capture and make use of it?
Isn't that the whole point of heat pumps? Grab energy from one locale, move it another to do useful work?
dmos62 4 hours ago
actionfromafar 3 hours ago
K0balt 4 hours ago
For every major trouncing of criterion we somehow invent 4 or 5 new requirements for it to be “real” AGI. Now , it seems, AGI must display human level intelligence at superhuman speed (servicing thousands of conversations at once), be as knowledgeable as the most knowledgeable 0.1% of humans across every facet of human knowledge, be superhumanly accurate, perfectly honest, and not make anything up.
I remember when AGI meant being able to generalize knowledge over problems not specifically accounted for in the algorithm… the ability to exhibit the “generalization” of knowledge, in contrast to algorithmic knowledge or expert systems. It was often referred to as “mouse level” or sometimes “dog-level” intelligence. Now we expect something vastly more capable than any being that has ever existed or it’s not “AGI” lmfao. “ASI” will probably have to solve all of the world’s problems and bring us all to the promised land before it will merit that moniker lol.
lukan 10 minutes ago
So do we have that? As far as I know, we just have very, very large algorithms (to use your terminology). Give it any problem not in the training data and it fails.
bawolff 3 hours ago
People base their notions of AI on science fiction, and it usually goes one of two ways in fiction.
Either a) skynet awakens and kills us all or
B) the singularity happens, AI get so far ahead they become deities, and maybe the chosen elect transhumanists get swept up into some simulation that is basically a heavenly realm or something.
So yeah, bringing us to the promised land is an expectation of super AI that does seem to come out of certain types of science fiction.
1 hour ago
ninetyninenine 11 hours ago
How come we have to build it and test it to know if it works?
Do we lack a mathematical model?
regularfry 8 hours ago
In a fluid, effects are local: a particle can only directly effect what it is in direct contact with.
In a plasma, every particle interacts with every other. One definition of a plasma is that the motion is dominated by electromagnetic effects rather than thermodynamic: by definition, if you have a plasma, the range of interactions isn't bounded by proximity.
This doesn't apply quite so much to (e.g.) laser ignition plasmas, partly because they're comparatively tiny, and partly because the timescales you're interested in are very short. So they do get simulated.
But bulk simulations the size of a practical reactor are simply impractical.
burnt-resistor 10 hours ago
Fission reactors are relatively "easier" to simulate as giant finite element analysis Monte Carlo simulations with roughly voxels of space, i.e., thermal conductivity, heat capacity, etc. I happened to have been involved with one that was 50+ years old that worked just fine because of all of physicists and engineers who carefully crafted model data and code to reflect what would be likely to happen in reality when testing new, conventional reactor designs.
The problems with fusion are many orders-of-magnitude more involved and complex with wear, losses, and "fickleness" compared to fission.
Thus, experimental physics meeting engineering and manufacturing in new domains is expensive and hard work.
Maybe in 200 years there will be a open source, 3D-printable fusion reactor. :D
KingOfCoders 10 hours ago
[0] https://en.wikipedia.org/wiki/Edward_Norton_Lorenz#Chaos_the...
HPsquared 7 hours ago
padjo 8 hours ago
jablongo 19 hours ago
1. Commonwealth (tokamak w/ high temp superconducting magnets)
2. Helion (field reversed configuration, magnetic-inertial, pulsed) ....
?. Wendelstein (stellarator)
Maybe stellarators will be the common design in 2060 once fabrication tech has improved, but for the near future I think its going to be one of the first two.
dralley 18 hours ago
I'm sure they developed some really useful technology in the process of building the thing, but I suspect they would have made more progress faster if they had taken a more iterative approach.
tobylane 34 minutes ago
prpl 14 hours ago
The first transistor in Silicon Valley wasn’t made by Shockley.
fpoling 14 hours ago
Tokamaks main problem is plasma instabilities. While Commonwealth may archive high Q briefly, nobody knows how plasma will behave at those conditions and long operations may not be possible.
Stellarators on the other hand do not have plasma stability problems. So my bet is on those.
audunw 6 hours ago
All approaches have huge hurdles to overcome. Helion may have bigger challenges on the Q side, but all-in-all I think the probabilities of being viable ends up similar.
All other fusion power plants are thermal power plants. I suspect all thermal power plants will end up being economically unviable in the world of renewables, for various reasons. They’re just too bulky and slow, and require special consideration wrt cooling. It’s one of the reasons why gas power is king these days.
If we think really far ahead, the scaling of thermal power plants is limited by the heat they put out. It ends up contributing to global warming just from the thermal forcing they apply to the environment. The effect of the ones we have today are already surprisingly significant. Helion is a path to being able to produce a huge amount of energy with fairly limited impact on the environment (eventually limited by the thermal energy they dump, but perhaps they can use thermal radiation panels that dump the waste heat energy directly to space)
niemandhier 18 hours ago
They are the only fusion startup I know of that was faster than their own timeline in the last year.
drewvolpe 14 hours ago
There's huge advantages to muon catalyzed if they can get it to work. Plants would be orders of magnitude smaller and cheaper to build.
GloamingNiblets 16 hours ago
[1] https://tae.com/tae-technologies-delivers-fusion-breakthroug...
actinium226 15 hours ago
Izikiel43 14 hours ago
LeFantome 9 hours ago