US Department of Energy: Fusion Ignition Achieved • Hacker News Board

Re: US Department of Energy: Fusion Ignition Achieved

#101

Post by JumpCrisscross » Tue, Dec 13, 2022, 5:37 PM UTC

prewett wrote: post #28

gjsman-1000 wrote: post #19

Earlier quoted context omitted.

Press release states: "meaning it produced more energy from fusion than the laser energy used to drive it." The 2.05 MJ put into the reaction includes the laser power supply then, it would seem, unless they are bad at press releases. But 2.05 MJ is not a lot of power.

If I remember from the article/discussion from yesterday, "laser energy" is the energy in the laser beam, but creating that 2 MJ laser beam required 200 MJ.

> creating that 2 MJ laser beam required 200 MJ

NIF uses notoriously inefficient lasers. They lase fine. Just not efficiently. From what I've seen, that 200 MJ would be closer to 20 MJ with modern equipment.

Still a gap! And there is still making the fuel, making and replacing the reactor as well as collection losses. But we're within two orders of magnitude of system break even, which is closer than we've ever been.

Re: US Department of Energy: Fusion Ignition Achieved

#102

Post by Ancapistani » Tue, Dec 13, 2022, 5:38 PM UTC

prvc wrote: post #47

micromacrofoot wrote: post #23

Earlier quoted context omitted.

Note that while this is important progress, it's a bit of specific accounting. The entire system still requires more energy input than output, but this isolated piece can now output a little more than input. > This is indeed a promising and exciting result, but we need to remember that this does not take into account the energy required to run the lasers that confine the reaction and other inefficiencies and losses.…

Since there will necessarily be overhead in any kind of finished design, this "threshold" is an arbitrary one to pass, no more significant that 90% or 125%, or any other round number.

Sort of.

We don't have a commercially viable technology here yet, but we've proven that it's at least viable for the part that needs to produce energy actually can produce energy.

As I understand it, now we start down the road of improving the ratio and optimizing the process.

FWIW, from my lay perspective it seems like the research NIF is doing is significantly smaller scale than the work being done elsewhere. That's a good thing in this case, because the output:input ration - the Q - seems to increase exponentially relative to input power.

Re: US Department of Energy: Fusion Ignition Achieved

#103

Post by bmmayer1 » Tue, Dec 13, 2022, 5:38 PM UTC

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

This is a stupid question but I don't know anything about fusion:

How is it possible for X energy to create X+Y energy in output? Doesn't that violate some fundamental law of physics?

Re: US Department of Energy: Fusion Ignition Achieved

#104

Post by mFixman » Tue, Dec 13, 2022, 5:39 PM UTC

Widespread energy generation nuclear fission is politically impossible in most Western countries.

Why are people optimistic that fusion won't have the same kind of problems, such as new plants being too expensive to build and old obsolete plants being too useful to decommission?

Re: US Department of Energy: Fusion Ignition Achieved

#105

Post by echelon » Tue, Dec 13, 2022, 5:39 PM UTC

pfdietz wrote: post #71

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

The Q needs to be something like 500 to 1000, not because of energy breakeven, but to produce enough energy that the shot is financially positive. The amount of fusion energy produced in this shot is worth a penny or two. (And even then, it's dubious a laser fusion scheme will be competitive with other energy sources.)

It will get there. It's just a matter of time and resources.

The destination will be a milestone for humanity, so we should not give up.

Re: US Department of Energy: Fusion Ignition Achieved

#106

Post by ceejayoz » Tue, Dec 13, 2022, 5:39 PM UTC

bmmayer1 wrote: post #103

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

This is a stupid question but I don't know anything about fusion: How is it possible for X energy to create X+Y energy in output? Doesn't that violate some fundamental law of physics?

You're using X energy to release Y energy from the fuel (the pellet, containing deuterium and tritium). It was there already, just not in a usable form.

Re: US Department of Energy: Fusion Ignition Achieved

#107

Post by megaman821 » Tue, Dec 13, 2022, 5:39 PM UTC

If ignition was achieved, why would they have to keep on shooting more fuel pellets? Shouldn't they just ignite one fuel pellet and feed in more fuel?

Re: US Department of Energy: Fusion Ignition Achieved

#108

Post by gene-h » Tue, Dec 13, 2022, 5:40 PM UTC

panosfilianos wrote: post #39

I tried to do some back-of-the-envelope calculations on what this means in regards to energy costs being saved, because I couldn't find a direct source (maybe GPT could help actually). Anyway, based on ITER [1] to equate the energy production of a 1000MW coal plant you would need 2.7t of coal for that plant or 250kg of deuterium and tritium for the fusion reactor (split equally). Based on [2] deuetrium costs about ~$…

[0] provides economic analysis for this type of power plant. They conclude it would not be unreasonable to get levelized cost of energy could get as low as $25/MWh. For this one really needs a high gain of 1000, although gains of 400 are a bit more reasonable, and a gain of around 100 may be economically competitive in some cases.

While the gain NIF achieved was about 1.5, there is good reason to expect it can be scaled up. Ignition is a runaway process, so small changes in the input can result in large changes in the output. Hydrogen bombs, which also use a burning plasma as was demonstrated here, also suggest that the gain and yield may be scaled up.

[0]https://royalsocietypublishing.org/doi/10.1098/rsta.2020.005...

Re: US Department of Energy: Fusion Ignition Achieved

#109

Post by karaterobot » Tue, Dec 13, 2022, 5:40 PM UTC

brofallon wrote: post #30

I'm still a little unclear on the benefits that fusion offers compared to things like wind and solar. I understand that we need to develop better storage technologies for the energy produced by wind and solar, but that seems so much easier than the challenges currently facing fusion. Wind and solar just seem so far ahead of fusion already - they're pretty cheap and very widely deployed on a global scale. In compariso…

Apart from the safety improvements and environmental benefits, it's a way to produce a ton of energy. I believe it's about 4 times as much energy from fusion compared to fission with the same amount of fuel. I'm a fan of solar and wind, but it's going to be way easier to power the entire world sustainably if you've got fusion in the mix.

Re: US Department of Energy: Fusion Ignition Achieved

#110

Post by simiones » Tue, Dec 13, 2022, 5:40 PM UTC

bmmayer1 wrote: post #103

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

This is a stupid question but I don't know anything about fusion: How is it possible for X energy to create X+Y energy in output? Doesn't that violate some fundamental law of physics?

The energy is "released" from the binding energy of the nuclei. It's similar to how throwing a bottle of nitroglycerine can generate a huge explosion, even though you use a tiny amount of energy to throw it.