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Merged How Close is power from Nuclear Fusion

Gord_in_Toronto

Penultimate Amazing
Joined
Jul 22, 2006
Messages
25,709
I keep reading articles like the following:

https://spectrum.ieee.org/zap-energy-fusion-reactor

and

https://spectrum.ieee.org/general-fusion-takes-aim-at-practical-fusion-power

It might be time to retire that overused joke about nuclear fusion always being 30 years away.

Fusion powerWP seems to explain the current state of the art.

I remember reading about:
The first experiment to achieve controlled thermonuclear fusion was accomplished using Scylla I at LANL in 1958. Scylla I was a θ-pinch machine, with a cylinder full of deuterium.
in the magazine Nuclear Engineering, to which my Dad subscribed, at the time the study was published and the negative impact it had on the fission industry and uranium stocks.

Still waiting for success. ;)
 
It sure seems like there's a lot more effort now that there was 10 or 20 years ago. Lockheed Martin's got a thing going, along with a bunch of other groups.

There are some relatively new superconductors now that work at liquid nitrogen temps, along with advances in the understanding of plasma physics, computing power, lasers and other odds and ends.

I suppose at a minimum they are advancing science and engineering. And maybe, just maybe, they'll actually advance enough to crack that nut.
 
I'm going to say it's still at least 30 years away.

I hope I'm wrong about that, but nothing I've seen recently persuades me that something that will actually produce surplus energy that can be used to generate electricity for the general consumer is going to arrive in the near future (within the next 10 or 20 years, say).

Fission power is a much more realistic alternative in the near term, even with its downsides. The important features are that it doesn't generate CO2 and it provides stable baseload power that doesn't depend on the weather or the time of day.
 
Fusion has been 20 years away for the last 50 years, when fusion researchers said "this is how much it will cost over the next 20 years," and Congress said "new election, who dis?"
[imgw=640]https://i.imgur.com/sjH5r.jpg[/imgw]


Don't hold your breath for ITER over in Europe. It's their space shuttle: a masterful feat of technical engineering in that it will work at all given it's a grossly expensive boondoggle that buries any hope of efficiency underneath a mountain of politically-driven design decisions.

Edited by Agatha: 
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Don't hold your breath for ITER over in Europe. It's their space shuttle: a masterful feat of technical engineering in that it will work at all given it's a grossly expensive boondoggle that buries any hope of efficiency underneath a mountain of politically-driven design decisions.

I dunno. The Space Shuttle program produced the RS-25 rocket engine. Apparently this is a good engine, and enough of an improvement over previous designs that it will be used on the Shuttle's successor, the Space Launch System.

Maybe ITER, while being a dead end overall, will produce a subsystem of similar lasting value. That would be neat.
 
I dunno. The Space Shuttle program produced the RS-25 rocket engine. Apparently this is a good engine, and enough of an improvement over previous designs that it will be used on the Shuttle's successor, the Space Launch System.
It doesn't matter whether it's an improvement or not. Congress has legislated that it be used, so it must. Exactly the kind of practical thinking that made the Space Shuttle such a reliable workhorse.
 
It seems to me that the larger and more complex a project is, the less of the overall timeline and cost are captured in the initial project plan. Not only that, but having been on the project management side of things myself, it seems reasonable to me that it should be so. It's simply not possible to accurately forecast and budget for all the contingencies on a project like the JWST. Nor would you want to try. A lot of the early phases of the project will be discovery, as you start to figure out what problems you're running into, and how much time and money you'll need to solve them. So I don't really have a problem with major projects being revised upwards in time and budget as they move towards completion. And more and more I'm reluctant to tar such projects as "late" and "over budget".

That said, we do seem to be getting slower at building stuff:

https://patrickcollison.com/fast

But I don't know if this means that NASA and its contractors are doing it wrong, or if it just means they're doing the best they can within the system of the world as it is today.
 
It seems to me that the larger and more complex a project is, the less of the overall timeline and cost are captured in the initial project plan. Not only that, but having been on the project management side of things myself, it seems reasonable to me that it should be so. It's simply not possible to accurately forecast and budget for all the contingencies on a project like the JWST. Nor would you want to try. A lot of the early phases of the project will be discovery, as you start to figure out what problems you're running into, and how much time and money you'll need to solve them. So I don't really have a problem with major projects being revised upwards in time and budget as they move towards completion. And more and more I'm reluctant to tar such projects as "late" and "over budget".

Fair enough, as long as people understand that from the outset.
 
It doesn't matter whether it's an improvement or not. Congress has legislated that it be used, so it must. Exactly the kind of practical thinking that made the Space Shuttle such a reliable workhorse.

Actually, it is practical thinking. The RS-25, whatever you want to say about the Shuttle, has been reliable. All the development costs are paid for. Practicality says it's good enough, so use it.

Impractical thinking would say, "We can do better, so let's fund an entirely new engine, with development which (if history is any guide) will run over budget and over schedule."
 
10 years. It's about 10 years away. Same as it was 60 years ago, same as it will be 60 years from now.
 
Fair enough, as long as people understand that from the outset.

I think the people involved in planning the project and approving the budget for the project understand that pretty well. I think the "late" and "over budget" narrative generally comes from people who know better but are looking for a short-term rhetorical advantage (e.g., people in Congress who must know how these things work but still need to get their dishonest sound bites in during election season), or people who don't want to know better because it's easier to be ignorant and just push their preferred narrative (e.g., journalists outside their area of expertise but who recognize a good story hook when they see one).
 
I think the people involved in planning the project and approving the budget for the project understand that pretty well. I think the "late" and "over budget" narrative generally comes from people who know better but are looking for a short-term rhetorical advantage (e.g., people in Congress who must know how these things work but still need to get their dishonest sound bites in during election season), or people who don't want to know better because it's easier to be ignorant and just push their preferred narrative (e.g., journalists outside their area of expertise but who recognize a good story hook when they see one).
My brain borked... I just read "pork".

And agreed. :-)
 
There was a time in my life when I expected to see useful fusion reactors come on line in my lifetime. Now, at age 68 I no longer expect that.
 
Fusion seems to have a slightly different problem, in that there are precursor technologies that need to develop/mature, and it's not clear how long that's going to take or how much it will cost to speed up the process.

There appear to be many people working on all sorts of possible solutions.. Maybe just the size of the effort well eventually give us a breakthrough. Or not, as the case may be.
 
Nuclear Fusion Breakthrough Confirmed: California Team Achieved Ignition

A major breakthrough in nuclear fusion has been confirmed a year after it was achieved at a laboratory in California.

Researchers at Lawrence Livermore National Laboratory's (LLNL's) National Ignition Facility (NIF) recorded the first case of ignition on August 8, 2021, the results of which have now been published in three peer-reviewed papers.

This is fantastic! Now we're only 19 years away from fusion power!
 
Actually it sounds like a major breakthrough. Why sneer instead of celebrate?

There is a lot to question here.

The article cited by shemp says
Once the hydrogen plasma "ignites", the fusion reaction becomes self-sustaining, with the fusions themselves producing enough power to maintain the temperature without external heating.
This reaction apparently lasted 100 trillionths of a second. Does that qualify as self sustaining? Looks to me like it didn't sustain but the actual situation is they claim it produced enough energy to sustain.

But that is suspect too. The energy measurements for this vary quite a bit. Some sources cite that it took 10 times as much energy to make this happened as was produced. Other put the ratio at over 250 to 1. Obviously you can't build a sustaining cycle with those kinds of losses.

Also seems they haven't been able to reproduce this yet.

Breakthrough of some kind I hope, but really hard to tell. Solid facts seem hard to come by.

ETA: I should point out I haven't read the three papers yet, but the summaries I've read and heard about don't contradict the things I just cited. My understanding is that they simply confirm that the 100 trillionth of a second reaction actually occurred.
 
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This reaction apparently lasted 100 trillionths of a second. Does that qualify as self sustaining?
It does if you only gave it 100 trillionths of a second of fuel to use up. It's just a type of positive feedback, and positive feedback reactions end whenever the conditions they depend on to keep feeding back change.

Some sources cite that it took 10 times as much energy to make this happened as was produced. Other put the ratio at over 250 to 1.
This kind of variation results from differences in what gets counted as input and what doesn't. There are multiple stages to setting up this kind of thing, which don't all have equal claims to being part of the input energy. For an analogy, consider a fire created at a fire-fighting school which destroys a house which was built just to be burned. Is the input energy the energy released by the ignition system alone? (I'd say "match" but I'm sure they don't use a match for this.) What about the energy it took to first get the ignition system up and running (striking the match)? What about the energy it took to produce the match? What about the energy it took to build the house? (A successful run of a fusion power plant would probably radiate parts of the machinery to death pretty quickly, causing the need to at least partially rebuild it before the next run.) After posting this, I'll try to find a Sabine Hossenfelder video which explained the differences between different fusion input energy levels in more detail than I'm recalling at the moment. I think there were a few different standard ways look at it called Q1, Q2, & Q3. (Part of her point was that the one that sounds the most optimistic is the one that gets published the most.)

Obviously you can't build a sustaining cycle with those kinds of losses.
Actually you can. You just wouldn't want to other than for research. Sustaining (positive feedback) and input/output ratio are two different things.
 
Delvo, thanks for the Hossenfelder youtube. That is exactly what I was getting at and applies big time here.

This reaction apparently lasted 100 trillionths of a second. Does that qualify as self sustaining?

It does if you only gave it 100 trillionths of a second of fuel to use up. It's just a type of positive feedback, and positive feedback reactions end whenever the conditions they depend on to keep feeding back change.

That doesn't make sense to meat all. This is an inertial confinement laser induced facility. Fusion reactors based on that process would be cyclic pulses with energy from the last pulse. This while methodology isn't even aiming for a self sustaining reaction.

This kind of variation results from differences in what gets counted as input and what doesn't.
Yes, of course. You've gone on to amplify my point especially with the youtube video. It was exactly the one I was trying remember late last night when I posted.

I can't think of any interpretation of "self sustaining" that it is at all accurate here. All the points that Hossenfelder made apply here plus the fact that this isn't even a methodology aiming for self sustaining reactions.

Your fire analogy is spot on, except it's spot on as an example of exactly what this didn't do.
 
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Maybe we could build a power plant next to the sun, use a grid of satellites to transfer power via lasers, hook the last one up to a space elevator, and transfer the power down to earth.

An added bonus is that any aliens who get weird readings about our solar system will wonder what the hell the idiots are up to.
 
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It seems like I see headlines about some fusion "breakthough" several times a year. I don't think it means that actual usable fusion energy is coming any time soon. It's always some kind of research and development step. They have yet to hook up a boiler and a turbine to one of these experiments. Also, it's going to be insanely expensive I bet.
 
It seems like I see headlines about some fusion "breakthough" several times a year. I don't think it means that actual usable fusion energy is coming any time soon. It's always some kind of research and development step. They have yet to hook up a boiler and a turbine to one of these experiments. Also, it's going to be insanely expensive I bet.

Yes. Even if/when it becomes possible to make something very hot for a significant period of time, that heat still has to be turned into a useful for of energy (starting with steam I would guess). Some significant engineering will be required.
 
Did you notice the date on that? That's the event we just discussed. See Shemp's post above.
 
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