Hacker News Reader

Comment by legitster | Hacker News Reader

This is pretty cool, but it's a good reminder that commercially viable fusion electricity still remains a looooong way off.

View on HN

Why is that the correct interpretation? It seems like another would be: "This is a ~33% improvement over a record set only three seeks ago. Innovation is rapidly accelerating to a point where plasma can be contained indefinitely."

And we are on the verge of AGI any week now. And Full Self Driving.

Are you trying to be sarcastic? There are cities where you can book a car to drive itself to you and then fully autonomously drive you to your destination.

Nothing ever happens

I don't think that qualifies as "full" self driving.

Aren't we talking about Waymo? It's not perfect everywhere but it's definitely already better than most people driving around SF. That's pretty full to me.

I guess they haven't been allowed on freeways yet?

Point taken, of course. But the fact that emerging technologies (or technologies that people wish would emerge) are often overhyped is not exactly an argument that "commercially viable fusion electricity still remains a looooong way off."

And, FWIW, I think it's far from clear at this point that progress towards AGI has been overhyped. It's true that we're not there yet, but how many serious people were actually predicting we'd get there in early 2025? If anything, that one seems like it could be coming up on us faster that many had expected. But, of course, nobody really knows — certainly not me.

Actually...same with FSD, now that I'm thinking about your comment a bit more critically. There are a few people out there who keep selling a snake-oil version of the technology. But, if you tune them out, my sense is that we've actually made pretty substantial progress on that problem too. After all, there are cities in the U.S. today where you can get picked up in a driverless taxi!

> Nevertheless, given the infrastructure needed to produce this energy on a large scale, it is unlikely that fusion technology will make a significant contribution to achieving net-zero carbon emissions by 2050. For this, several technological sticking points need to be overcome, and the economic feasibility of this form of energy production must still be demonstrated.

It's very cool, but the article itself paints a long time line. Indefinite containment is just one part of the puzzle.

Being a viable form of electricity and becoming a significant contributor to mitigating climate change by a specific date are two different things. Geothermal is a viable form of electricity for example even if it is less than 1% of power produced.

I think if the "burns" are long enough, it will be sufficient to extract net energy...

actually...

All that depends on how much burn heat we can get from those ~30mins burns... :)

Commercially viable likely also means: cost competitive with nuclear fission. Which might well never happen, since the reactor designs for fusion are orders of magnitude more complex (and therefore more expensive).

They also need a lot of ignition energy which requires a powerful separate power source, which limits where the fusion reactor can be built.

Moreover, there is the issue of the reactor core being degraded by the heavy neutron radiation which is produced by the fusion reaction. So the chamber has to be replaced regularly. Which may also be quite expensive.

Does the commercial viability change when one considers regulatory constraints on building new fission plants? People may be more inclined to allow fusion reactors than fission reactors, since the former doesn't require uranium. (I'm sure there are dangerous failure modes for fusion, like there are for everything else, but Chernobyl continues to haunt the nuclear industry in the popular imagination.)

I guess the existing regulations apply to all reactors which handle radioactive materials, not just to fission reactors which produce radioactive uranium isotopes with long half-life, and which include the risk of a nuclear meltdown. Though it would make sense if the safety requirements are significantly lower for fusion reactors because of their higher innate safety.

My understanding as well is that fusion could take care of base load, but it can't be scaled up or down based on grid demand to the same degree that fission reactors can. So fusion and renewables alone would not be capable of a carbon-free future grid.

>the issue of the reactor core being degraded by the heavy neutron radiation which is produced by the fusion reaction.

There are some reactor designs that use aneutronic fusion, which eliminate this particular issue.

https://en.wikipedia.org/wiki/Aneutronic_fusion

CFS is building their demo reactor that should achieve Q>1 and are already building their first commercial plant: https://blog.cfs.energy/cfs-will-build-its-first-arc-fusion-...

Barring some kind of engineering failures and delays they seem on track to have things ready in the early 2030s.

I think this is hopelessly optimistic. From what I can tell, they have not even started building the ARC reactor. There is about zero reason to believe that all the completely unproven concepts, like the molten-salt liquid blanket (or tritium breeding in general) are gonna work without a hitch and zero delays-- thats just straight up self-delusional.

In comparison with ITER, the have the advantage of newer magnet technology (which certainly helps!), but thats the only actually proven thing, and every other aspect of ARC is basically complete vaporware.

It would be a very pleasant surprise to have them extract electrical energy from the thing in early 2030, but I'm not even holding my breath for first plasma by then. But we'll see.

Our first clue that it was bollocks was when it was called ARC reactor.

No one has demonstrated stable plasma operations for any lengths of time and they are claiming to not just get Q-plasma > 1 but Q-total > 1 by 2030? This is more optimistic than Full Self Driving by 2016

You fell for the oldest trick in the fusion book.

We don't know what innovation will bring or when. The important thing is trying and the direction of travel.

No it’s pointless doing it because some guy on HN said it’s a long way off and therefore you are not allowed to be excited or enthusiastic about it.

What's pointless for anyone who cares about fusion is commenting on it from the peanut gallery (i.e., any form of social media) rather than participating in R&D in any way whatsoever. The same goes for online outrage: https://par.nsf.gov/servlets/purl/10095997

This entire site is nothing more than a sales and marketing tool and otherwise exists to waste peoples' time.

> What's pointless for anyone who cares about fusion is commenting on it from the peanut gallery (i.e., any form of social media) rather than participating in R&D in any way whatsoever.

Some of us do both :)

Beautiful irony in getting ratioed for this post.

What's funny is that AI has been failing to be achieved for much longer than fusion energy yet so many here are convinced we're on the cusp of an AI apocalypse.

I have more faith in fusion power in 20 years than anyone claiming AGI is coming in the exact same timeframe.

The thing is, after repeatedly getting excited about commercial fusion power for the past sixty years, it's tough to maintain enthusiasm.

For me I worry it's like the search for the northwest passage. (https://en.wikipedia.org/wiki/Northwest_Passage). Explorers spent about 400 years searching for something that they knew just had to be there, but when they finally did it (1957), it really wasn't important anymore.

The Northwest Passage is important now tho. The short path from most of Eurasia to North America goes through the Arctic. Ice caps are diminishing/going away. The US wants Greenland. All of these are related.

> The thing is, after repeatedly getting excited about commercial fusion power for the past sixty years, it's tough to maintain enthusiasm.

It’s very easy if you’re even a tiny bit interested in the scientific aspects. Since we started we’ve had several generations of superconductors, huge advances in our understanding of materials and plasma physics (a bit niche but still very cool).

ITER itself is fascinating if you’re into large-scale engineering and planning. If you are into this and not interested in ITER, I would recommend having another look.

> Explorers spent about 400 years searching for something that they knew just had to be there, but when they finally did it (1957), it really wasn't important anymore.

Yes, it’s a risk and it might well end up that way. Still, many discoveries have already been made along the way, and it is impossible to predict its success or failure without actually trying to do it.

Does anyone have a top 5 issues list of things that are holding up fusion progress? Like there are basic material science issues that still need work to bring costs down, so that critical materials don't cost too much? Or there is still some theoretical plasma physics that we're still working out the details on? Or magnetic confinement simulations are still too crude, and we need 100x on computing power. Or whatever.

If I understand correctly, the Top 1 and 2, 3, 4, 5 etc. issue is how to make that plasma do actual work. So far the designs which boast Q>1 or are close enough, all produce plasma in short burst and no one has invented a way to make that burst generate electricity somehow. And tokamak design has clearer path to generating electricity but have problems in reaching stable Q>1 at all. This is all very amateurish understanding, please correct me if I'm wrong.

Series of short bursts, which heat a neutron-absorbing fluid. That part is relatively straightforward.

Helion is an exception, since they have a different fuel which gives them a way to extract electricity directly.

1. We don't have a perfect understanding of plasma dynamics and how they'll react to different conditions. Predicting plasma instabilities before they mess with your reactor remains a big challenge for our computation capabilities.

2. Yeah, material science is also a big one. When you are working with the magnetic forces typical in a modern fusion reactor, your materials undergo a lot of mechanical stress. The "first wall" that has to bear the brunt of the nuclear reactions becomes radioactive. Some plasma ions invariably go off trajectory and we have a "diverter" to prevent them from hurting the reactor but that reduces the temperature.

3. Our reactors aren't efficient enough. Everyone taking about "q" value means the energy they put into creating the reaction to get the plasma to fuse. It's called q-plasma which is a misleading metric. The true breakthrough will be sustained q-total, which will be the ratio of the total energy you get out over the total energy you put in. Nobody in the industry likes to talk about it, because we are decades away from reaching this.

4. Modern designs are becoming extremely expensive. The most serious design right now is being funded not by a state of a country but by the biggest countries in the planet.

5. Someone help me here I've ran out of points

5. The fuel is notoriously difficult to contain. There will be leaks, and even small ones can spoil the reaction and tip your device into unpredictability. Also, the fuel has a tendency to infiltrate metals and embrittle them.

5. Working big pieces of steel and making large process plants is not cheap or easy.

6. Volumetric power density sucks compared to fission reactors. This leads to #4, since for a given power output the reactor is an order of magnitude larger or even worse. Designs with some hope of evading this showstopper may be possible, but they are rare on the ground, and the tokamak doesn't appear to be one of them.

I'm afraid the top 1 issue forever is that it really only works if you are a sun. No need to try and harvest or contain the energy, high energy neutrons damaging the whole thing is a non-issue, and the gravity does the rest.

We already have a fusion source and a way to harvest it from afar in solar panels.

Reply on news.ycombinator.com