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Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

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Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#101

Post by survirtual »

skelpmargyar wrote: post #77
nayroclade wrote: post #46

Earlier quoted context omitted.

Except it isn't the HN readership who choose to constantly frame these stories in terms of engineering. From the article: "These and other scientific, technological and engineering hurdles will need to be overcome before fusion will produce electricity for your home. Work will also need to be done to bring the cost of a fusion power plant well down from the US$3.5 billion of the National Ignition Facility. These step…

What that that paragraph means is that things that do not exist will cost money to bring into existence. A significant amount. It's not a critique. This is not new. This is not a fusion problem. There is an initial cost and development to any new technology. This technology is particularly difficult, however. It's also sustainable real renewable energy. You have to worry about actually being able to invent something…

The Manhattan Project cost $2 billion, equivalent to $23 billion in today’s dollars — for the entire project.

~$2 trillion was used to bailout big businesses. If money was properly accounted for, $2 trillion could fund approximately 87 Manhattan Projects simultaneously in today’s dollars.

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#102

Post by jacquesm »

rob74 wrote: post #43

Still unconvinced why this is such a major breakthrough - it may be the first net-positive controlled fusion, but the distinction between controlled and uncontrolled fusion is a bit academic in this case. In uncontrolled fusion ( https://en.wikipedia.org/wiki/Thermonuclear_weapon ), you are using a nuclear fission primary stage to generate enough energy to start the fusion reaction in the secondary stage. In the NIF,…

And that's before we get into the total system efficiency issues.

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#103

Post by randallsquared »

sigmoid10 wrote: post #86
rob74 wrote: post #43

Still unconvinced why this is such a major breakthrough - it may be the first net-positive controlled fusion, but the distinction between controlled and uncontrolled fusion is a bit academic in this case. In uncontrolled fusion ( https://en.wikipedia.org/wiki/Thermonuclear_weapon ), you are using a nuclear fission primary stage to generate enough energy to start the fusion reaction in the secondary stage. In the NIF,…

You greatly underestimate the order of magnitude difference of produced energy in these two examples. You can't contain a bomb's hydrogen fusion reaction in a chamber for the simple reason that you need a nuclear fission warhead just to ignite it. So if you want to produce useful, controlled energy outside of killing things, the lasers are your only shot for inertial confinement fusion. Yes they still get damaged, bu…

> You can't contain a bomb's hydrogen fusion reaction in a chamber

You certainly can, if you use a large enough chamber. Pacer was exactly this. You just have to accept high proliferation risk.

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#104

Post by HPsquared »

oblio wrote: post #52
skelpmargyar wrote: post #17

Earlier quoted context omitted.

It's better to focus on standardised production lines for small fission reactors currently if your goal is to produce energy for the power grid right now, but that's not what cutting-edge research or science is about. Whoever launched the first firework probably didn't see how people could walk on the moon either. Science is rarely a linear path. It's also rarely "I have this problem so I solved it this way." That's…

Nuclear fusion is stuck into an "early MASER/LASER phase". Laser was cool, but nobody knew what to do with it. These days we're at the stage where we're thinking: what can't we do with it??? But for about 3 decades (before CDs, basically) laser was a pop science laughing stock, more or less. And fusion is much harder plus has been talked about and hyped for at least as long.

Fusion is different: we know what we want it to do, but it's proving very difficult. It's a problem in search of a solution, unlike lasers which were (initially) a solution in search of a problem.

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#105

Post by oblio »

HPsquared wrote: post #104
oblio wrote: post #52

Earlier quoted context omitted.

Nuclear fusion is stuck into an "early MASER/LASER phase". Laser was cool, but nobody knew what to do with it. These days we're at the stage where we're thinking: what can't we do with it??? But for about 3 decades (before CDs, basically) laser was a pop science laughing stock, more or less. And fusion is much harder plus has been talked about and hyped for at least as long.

Fusion is different: we know what we want it to do, but it's proving very difficult. It's a problem in search of a solution, unlike lasers which were (initially) a solution in search of a problem.

Yes, you're right, I guess I blanked out while writing the original comment.

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#106

Post by phkahler »

sigmoid10 wrote: post #86
rob74 wrote: post #43

Still unconvinced why this is such a major breakthrough - it may be the first net-positive controlled fusion, but the distinction between controlled and uncontrolled fusion is a bit academic in this case. In uncontrolled fusion ( https://en.wikipedia.org/wiki/Thermonuclear_weapon ), you are using a nuclear fission primary stage to generate enough energy to start the fusion reaction in the secondary stage. In the NIF,…

You greatly underestimate the order of magnitude difference of produced energy in these two examples. You can't contain a bomb's hydrogen fusion reaction in a chamber for the simple reason that you need a nuclear fission warhead just to ignite it. So if you want to produce useful, controlled energy outside of killing things, the lasers are your only shot for inertial confinement fusion. Yes they still get damaged, bu…

>> This news shows that practical fusion is now only an engineering problem, not a fundamental physics one - like it still is for Tokamaks and Stellarotors.

Hahaha! That is the funniest BS I've heard about it yet! Fusion has always been "only an engineering problem" since the first H-bomb and this approach might actually be the farthest from useful even with is.

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#107

Post by jackmott42 »

I can tell you that regular people took the announcements as a sign that nuclear fusion as a real useful thing is imminent, and couldn't be convinced otherwise!

But then if your announcements are completely rational you don't get as much funding. A lot of us nerds on HN don't like it when people do propaganda, but I assume we also like to win, right?

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#108

Post by dotancohen »

HPsquared wrote: post #97
sigmoid10 wrote: post #86

Earlier quoted context omitted.

You greatly underestimate the order of magnitude difference of produced energy in these two examples. You can't contain a bomb's hydrogen fusion reaction in a chamber for the simple reason that you need a nuclear fission warhead just to ignite it. So if you want to produce useful, controlled energy outside of killing things, the lasers are your only shot for inertial confinement fusion. Yes they still get damaged, bu…

Parent was basically saying it has not been a physics problem for decades, it's already an engineering problem and there is no change there. The physics are known to work and have been demonstrated decades ago in a different engineering context (i.e. weapons).

As I understand it - correct me if I'm wrong - one of the consequences of the December 5 experiment is that the engineering uncertainty was brought into the realm of "this now fits the progress of engineering, so we expect to be able to engineer the thing given sufficient capital and time", rather than the previous "we have no idea if we'll ever be able to engineer this thing".

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#109

Post by koppe »

jackmott42 wrote: post #107

I can tell you that regular people took the announcements as a sign that nuclear fusion as a real useful thing is imminent, and couldn't be convinced otherwise! But then if your announcements are completely rational you don't get as much funding. A lot of us nerds on HN don't like it when people do propaganda, but I assume we also like to win, right?

They literally said it would take decades for this to become "useful", I don't think they made it seem closer than it is at all

Re: Nuclear physicist explains why fusion ignition is hailed as a major breakthrough

#110

Post by willis936 »

moffkalast wrote: post #53
albertopv wrote: post #22

Real Engineering published a video about Helion Energy company. I don't have the tools to filter out commercial BS, still it seems to me to be most promising effort. The idea to get electricity directly from magnetic fields instead of boiling water is very intriguing.

I've also been quite surprised watching that one, it's completely novel approach to fusion and it may be the best way to mass adoption. If they can make it work that is. What most surprised me about NIF's ignition announcement was that this was even news. I'd assumed for years that most if not all tokamaks and stellerators could already achieve at least some brief fusion, just not to a useful degree. Turns out they'r…

The milestone is that they surpassed Qplasma > 1. This has not been achieved before even though fusion has been done in ICF and MCF machines.

Qplasma > 1 is significant because it now enters a regime where the burning fuel heats up unburnt fuel. In MCF machines this is referred to as a burning plasma. In ICF machines this is referred to as ignition. Ignition in MCF machines is Qplasma = infinity, where no external heating is used. This is on the table (maybe, theoretically), we just need to build machines with sufficiently high triple product and plasma control surfaces then learn how to do it. We'll have MCF burning plasma machines soon.

https://twitter.com/jb_fusion/status/1506964692627034118

Helion has not talked about triple product numbers. I wish they would, because that's the key metric for understanding how far they are from D-He3 burning plasma. Also, having the triple product history for all of their machines would help show scaling laws. These are currently closely guarded secrets. Targeting D-He3 fuel means a much higher coulomb barrier needs to be overcome and a higher triple product is needed to reaching burning plasma.

Check out slide 40 for more details on fusion fuels.

https://suli.pppl.gov/2022/course/IntroductionToFusionEnergy...

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