Science is rarely a linear path. It's also rarely "I have this problem so I solved it this way." That's more engineering than science. It's really disappointing to me to see people, for lack of a better term, just shit on this accomplishment on HN when it's some seriously amazing stuff. It seems like a lot of people here don't understand science, they only understand engineering and then think about engineering mostly from a dull business and product oriented perspective.
"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 steps will require significant investment from both the federal government and private industry."
If fusion research scientists continue to insist that their research has any viable path to use in commercial power generation, and to demand large amounts on funding on that basis, then they should expect to be critiqued on that same basis.
We don't really know what path fusion research will lead to. It's science. We don't know what we could find out tomorrow that could apply this research. But even the promises of commercial power generation alone should be enough to keep funding the project whether it will happen in 50 years or 100 years. It's not like they aren't making progress. You can't rush research and also under fund them.
~$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.
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.
Yup:
In college English classes I took, they wanted the students to write term papers. Ah, sure, they expected some review of some case of belles lettres, maybe Medieval French romantic poetry!!!!
Instead, in one case, I picked the transistor and another, the laser.
For the laser, I had no idea of the applications. For the transistor, all I knew was, what it seemed was all Bell Labs had in mind -- replace their usage of vacuum tubes, that is, analog amplifiers and not digital, Nyquist sampling, etc., even though Shannon was at Bell Labs, etc.
The idea of a few billion transistors on a sheet of silicon about the size of a large postage stamp, 16 cores, 64 bit addressing, 4.0 GHz clock, etc. -- beyond all expectation or belief. The graphics processors -- still less belief! Lasers sending trillions of bits per second per hair-thin glass fiber -- not even ready for science fiction!
No doubt I picked the transistor and the laser out of media hype. So at least some people in the media expected something from those two. Here the media was not wrong, and in the long term the hype was way below the reality.
No one is shitting on the research itself. But the PR around this story has carpet bombed sci-comm as a potential practical energy source. Not as basic research.
So it's perfectly reasonable to ask if there's a there from a commercial POV. And to note out that currently there really isn't.
If they really had announced a viable commercial product everyone here would be cheering.
The comment I replied to stated "Better to focus on standardised production lines for small fission reactors." To you, is that not shitting on the research? It implies the only purpose for this research is for power generation. And that it is clearly inferior to small fission reactors for that purpose, when the technology doesn't even exist yet. It just diminishes the accomplishment as a whole. It's so short sighted from a group of people who's jobs only came to existence <100 years ago.
So it takes an incredible amount of precision engineering to produce these tiny diamond pellets of fuel which then produce an even tinier amount of energy while being destroyed in the process. There is no indication whatsoever that the pellets can be scaled up due to the incredible difficulty of scaling the precision geometry involved.
So I remain incredibly skeptical that this is anything more than hype for a project that's really about maintaining nuclear weapons stockpiles. I sincerely doubt this approach will lead to a real production power plant without some major research into how to overcome the requirement for extreme precision geometry and a similar effort to scale up the size of the reaction. Then throw the laser efficiency issue into the mix!
Could it be made from a metal that is in greater supply?
Could they really fire this design more than twice a minute?
For example, the maximum efficiency of a laser is limited by the quantum efficiency of the laser material, which is the ratio of the number of photons emitted by the laser to the number of charge carriers (electrons and holes) injected into the laser material. The quantum efficiency of most laser materials is less than 100%, which means that there is a limit to the efficiency that can be achieved.
In addition, the efficiency of a laser is also limited by the thermodynamic laws of thermodynamics, which state that it is not possible to convert heat or any other form of energy into work with 100% efficiency. This means that there is always some amount of waste heat generated when a laser is operated, which limits its efficiency.
In other words, fusion is unlikely to be using lasers for the ignitions.
UPDATE: People here seem to believe in self-sustained fusion, but this has never been tried or proven to be possible - no one know how much energy is needed for repeated ignition.
The current plan is to re-ignite new pellets fed into the containment.
That is not true. You can of course not make a 10 % efficient laser more than 10 times more efficient, but there is no limit to how much more efficient you can make a laser in general, you just have to start with an inefficient enough one.
And the NIF lasers are quite inefficient, according to Wikipedia - which might have slightly outdated numbers as someone pointed out to me - they turn 422 MJ stored in capacitors into 1.8 MJ UV laser light, that is an efficiency of 0.43 %. Bringing this up to the 20 % you mentioned would already almost be a factor of 50. Also not all of the gain has to come from more efficient lasers, the fusion process could also be made more efficient.
But you are of course correct that there is some general limit to laser efficiency, therefore the question is if the fusion gain can compensate this and all additional losses during the conversion into electricity further down the line.
Can we stop pretending this isn't about nuclear weapons research and - basically - continued funding?
LLNL is at least a decade behind its initial predictions of ignition. The current lasers may be inefficient but they've been fine-tuned very precisely for optical quality. There's no guarantee more efficient lasers would have the same characteristics and could be focussed in the same way.
I'm sure LLNL know the maximum theoretical fusion gain for a realistic pellet design, and it's worth nothing that that number hasn't been mentioned anywhere. Clearly there's only so much energy available for each cycle. If that energy is on the wrong side of what's needed to release it even after efficiency improvements, the entire system isn't workable, no matter how it's re-engineered.
The laser practicality issue that prevents this from directly becoming a power source would also be a major barrier to its application as a weapon. The laser fires in the UV-B (351 nm), which is scattered and attenuated by air, to say nothing of smoke or dust; it also requires incredibly high targeting precision (<2 mm target diameter) and consequently precise placement of a target weighing only milligrams. Additionally, the various optical components of the laser must be very well aligned, which is difficult to achieve in any battlefield conditions. And the whole thing is a very obvious and vulnerable target.
I ascribe a small possibility to its utility as a weapon in space, but practically zero on Earth without other major developments.
>I'm sure LLNL know the maximum theoretical fusion gain for a realistic pellet design, and it's worth nothing that that number hasn't been mentioned anywhere.
I wouldn't be so sure. Fusion is in general quantum chromodynamics, which is not so well characterized (being the subject of the famous YM mass gap conjecture). Even in this case it was stated that the yield exceeded expectations and damaged the sensors, which was probably not desired.
Fusion is similarly incomprehensible to us here and now. There are untold advancements in materials sciences and engineering technologies that need to happen before it's possible so we have to invest in trying to so we can make those advancements in order to make it possible.
"In our laser-produced plasma (LPP) source, molten tin droplets of around 25 microns in diameter are ejected from a generator at 70 meters per second. As they fall, the droplets are hit first by a low-intensity laser pulse that flattens them into a pancake shape. Then a more powerful laser pulse vaporizes the flattened droplet to create a plasma that emits EUV light. To produce enough light to manufacture microchips, this process is repeated 50,000 times every second."
https://www.asml.com/en/technology/lithography-principles/li...
Transistors, microchips and lasers were not invented yet in 1943. How would one even guess that it could soon be a viable business to build a giant machine that shoots molten tin droplets at 50,000 Hz to produce a particular bandwidth of light so that you could create billions of tiny computers out of sand?
Hopefully fusion is on a similar path where the description of 2100's commercial reactor will sound similarly incomprehensible to us.
In the extreme you could say that today we have only one computer, the ASML computer [2], since they are the only ones making the machine that makes the machine.
[1] https://en.wikipedia.org/wiki/Aladdin_(BlackRock)
[2] ASML: TSMC's Critical Supplier, Explained https://www.youtube.com/watch?v=CFsn1CUyXWs
Well, that's easy. I forgot who mentioned it, but crypto has 0 support for actual clients, and the vast majority of day-to-day computing now happens on mobile end user devices (phones, tablets, laptops). So besides (what should be) this fatal flaw, the second thing crypto requires you is to manage your keys SUPER carefully yourself or a server.
Nobody[1]'s going to do that. I'm a techie and I don't want to maintain my own servers. What hope does Joe Locksmith have?
So in practice crypto will always centralize.
[1] 99% of the population.
It just needs to enter into state of self sustained reaction that is net positive.
Ignition itself can be horribly inefficient.
Nobody is designing fussion where ignition's output is directly used for the whole system to reignite again.
It would be equivalent to moving hand with match that fires a match, where energy from ignition is used to trigger another hand to move another match.
Aneutronic fusion could possibly have a future, but hardly anybody is working on that.
Even in engineering problems, two people started a little electric car company in 2003. No, youknowwho wasn't involved yet. Would you have said "i can't see how electric cars can ever be workable" then?
Sooo, for Mars, just put the solar panels near the equator and fairly densely all around the circumference. Then, wow, have solar power 100% of the time!
Do the same on Earth??? Ah, have some jungles, mountains, two major oceans, and a lot of bad weather. For the oceans, sure, have floating solar arrays. Right, need to think about how deep the power cables to the shore would be, 3-7 miles down and then back up?
But the Internet has some cables across oceans!! Sooo, we could also have power cables???
Ah, sounds like only for Mars!
R&D labs aren't known for their industrial optimization unless that's their research goal. They proved this from the perspective of the fuel pellet - now they have to increase energy yield (larger fuel?) , reduce total system power, etc.
That said, they doubled energy yield in less than a year. The early exponential function on emerging technologies is always fun.