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There was a talk about the state of nuclear fusion by some MIT folks linked here on HN a few days ago. One of the biggest takeaways was that many fusion efforts

There was a talk about the state of nuclear fusion by some MIT folks linked here on HN a few days ago. One of the biggest takeaways was that many fusion efforts are very far away (3 to 6+ orders of magnitude) on the most important metric, Q, which is energy_out / energy_in. Additionally, much press and public discussion completely fail to discuss this and other core factors that actually matter for making fusion viable. I remember Tri-alpha being listed on one of the slides near the bottom left of the plot, 4 or 5 orders of magnitude away from break even, where Q = 1 (someone please correct me if I'm remembering incorrectly). Is the 50% improvement described in the article meaningful, as that would only be a fraction of an order of magnitude? I understand the broader concept of combining experts and specialized software on complex problems is a powerful idea -- I'm just wondering if this specific result actually changes the game for Tri-alpha.

deleted 9y ago
[deleted]
a1371 9y ago
I also watched that MIT talk and it was quite insightful; however, as I searched a bit more, I realized that the metrics involved in the presentation are only for achieving surplus in the generated energy from fusion. When it comes to industrializing the idea, the scope is far broader. For example, the speaker was saying that they can use the neutron streams as the result of fusion for creating tritium. In reality, capturing the neutrons is much more complex than that [1]. Some of those may deposit on the inner surface of the tokamak and have to be recovered by 99% to have breakeven. The nuclear waste is another concern in the opposite case. Given all these, you get a sense that why companies like General Fusion [2] get funded. He showed that General Fusion is very far away in his metrics. But the pinching technology the company is offering, allows for continuous use of the fusion in rapid bursts (like an automatic rifle). When I met them at the Globe conference, they were claiming that they will be ready for production within 5 years of achieving a surplus. I am not sure how fast the tokamak can get there. Source: 1. http://thebulletin.org/fusion-reactors-not-what-they%E2%80%99re-cracked-be10699 http://thebulletin.org/fusion-reactors-not-what-they%E2%80%9... 2. http://generalfusion.com/ http://generalfusion.com/
le-mark 9y ago
I also watched that video, and was also a bit dismayed. It seemed to me that a lot of projects with the very low Q numbers weren't at the point of going for high Q numbers. The project I follow is Polywell[1], and my understanding is they've been working on confirming the physics of their approach (which involves 'wiffle ball' confinement) and so have not attempted pushing for break even energy production. The video was eye opening though, I had no idea that high temperature super conductors were set to revolutionize tokomaks. If the potential is there, it seems like the prudent thing to do would be to reset the ITER project, and redesign utilizing the current generation of high temperature super conductors. But I'm just an interested observer, what do I know? [1] https://en.wikipedia.org/wiki/Polywell https://en.wikipedia.org/wiki/Polywell
hyperbovine 9y ago
But hey, string ~20 consecutive 50% improvements together and you're at four orders of magnitude :-)
- markvdb 9y ago
  You might allowed to be much more optimistic. A 50% increase could be much much more significant depending on the parameter optimised. Tokamak magnetic field strength for example has a factor ^4 effect towards net energy. Have a look at https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk , as previously discussed here: https://news.ycombinator.com/item?id=14834390 https://news.ycombinator.com/item?id=14834390 .
DennisP 9y ago
Tri Alpha has been running at relatively low temperature, about 10 million degrees, while they figured out how to make their plasma stable. They achieved that in 2015 with their older reactor. According to their model, the plasma should get more stable at higher temperature. They just finished a new reactor they'll use to test that. It'll hit temperatures closer to 100 million degrees. If they're right about plasma stability, they'll be ready to attempt net power with a full-scale demo reactor. Since they're using boron fuel they'll need to get the temperature to about three billion degrees, but they say pumping in more heating is relatively easy. (Source for all that: I saw one of the Tri Alpha people speak at an MIT Solve conference the other year.) So the 50% improvement isn't a make-or-break thing, but I'm sure it'll help. In general, being able to run simulations in hours instead of months will probably help a lot.
drjesusphd 9y ago
> One of the biggest takeaways was that many fusion efforts are very far away (3 to 6+ orders of magnitude) on the most important metric, Q, which is energy_out / energy_in. Keep in mind tokamaks have reached Q=0.7.

deleted 9y ago

[deleted]

a1371 9y ago

I also watched that MIT talk and it was quite insightful; however, as I searched a bit more, I realized that the metrics involved in the presentation are only for achieving surplus in the generated energy from fusion. When it comes to industrializing the idea, the scope is far broader. For example, the speaker was saying that they can use the neutron streams as the result of fusion for creating tritium. In reality, capturing the neutrons is much more complex than that [1]. Some of those may deposit on the inner surface of the tokamak and have to be recovered by 99% to have breakeven. The nuclear waste is another concern in the opposite case. Given all these, you get a sense that why companies like General Fusion [2] get funded. He showed that General Fusion is very far away in his metrics. But the pinching technology the company is offering, allows for continuous use of the fusion in rapid bursts (like an automatic rifle). When I met them at the Globe conference, they were claiming that they will be ready for production within 5 years of achieving a surplus. I am not sure how fast the tokamak can get there. Source: 1. http://thebulletin.org/fusion-reactors-not-what-they%E2%80%99re-cracked-be10699 http://thebulletin.org/fusion-reactors-not-what-they%E2%80%9... 2. http://generalfusion.com/ http://generalfusion.com/

le-mark 9y ago

I also watched that video, and was also a bit dismayed. It seemed to me that a lot of projects with the very low Q numbers weren't at the point of going for high Q numbers. The project I follow is Polywell[1], and my understanding is they've been working on confirming the physics of their approach (which involves 'wiffle ball' confinement) and so have not attempted pushing for break even energy production. The video was eye opening though, I had no idea that high temperature super conductors were set to revolutionize tokomaks. If the potential is there, it seems like the prudent thing to do would be to reset the ITER project, and redesign utilizing the current generation of high temperature super conductors. But I'm just an interested observer, what do I know? [1] https://en.wikipedia.org/wiki/Polywell https://en.wikipedia.org/wiki/Polywell

hyperbovine 9y ago

But hey, string ~20 consecutive 50% improvements together and you're at four orders of magnitude :-)

markvdb 9y ago
You might allowed to be much more optimistic. A 50% increase could be much much more significant depending on the parameter optimised. Tokamak magnetic field strength for example has a factor ^4 effect towards net energy. Have a look at https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk , as previously discussed here: https://news.ycombinator.com/item?id=14834390 https://news.ycombinator.com/item?id=14834390 .

DennisP 9y ago

Tri Alpha has been running at relatively low temperature, about 10 million degrees, while they figured out how to make their plasma stable. They achieved that in 2015 with their older reactor. According to their model, the plasma should get more stable at higher temperature. They just finished a new reactor they'll use to test that. It'll hit temperatures closer to 100 million degrees. If they're right about plasma stability, they'll be ready to attempt net power with a full-scale demo reactor. Since they're using boron fuel they'll need to get the temperature to about three billion degrees, but they say pumping in more heating is relatively easy. (Source for all that: I saw one of the Tri Alpha people speak at an MIT Solve conference the other year.) So the 50% improvement isn't a make-or-break thing, but I'm sure it'll help. In general, being able to run simulations in hours instead of months will probably help a lot.

drjesusphd 9y ago

> One of the biggest takeaways was that many fusion efforts are very far away (3 to 6+ orders of magnitude) on the most important metric, Q, which is energy_out / energy_in. Keep in mind tokamaks have reached Q=0.7.