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US Department of Energy: Fusion Ignition Achieved

energy.gov

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Re: US Department of Energy: Fusion Ignition Achieved

#971

Post by rrrrrrrrrrrr2 »

azinman2 wrote: post #956
rrrrrrrrrrrr2 wrote: post #727

Earlier quoted context omitted.

I think a major bottleneck for fusion research from the lay public (including myself) is lack of interest. Fission reactors work really well and have been around for 50+ years. If we are going to go nuclear instead of renewable, we need to address the elephant in the room. The elephant in the room is: why not just fission?

Fukushima most recently

And somehow harnessing the power of the literal sun will have a better safety rate? It's all speculation at this point because fusion doesn't exist yet... but it does seem like a huge undertaking to get superior safety over fission.

Re: US Department of Energy: Fusion Ignition Achieved

#972

Post by pauljurczak »

kubanczyk wrote: post #879
pauljurczak wrote: post #820

Earlier quoted context omitted.

> USA probably won't have an effective arsenal within a century. If other countries joined, it would be a great outcome.

> > USA probably won't have an effective arsenal within a century. > If other countries joined, it would be a great outcome. Why the optimism? Without MAD, it's nearly certain that we'd have a world war at some point in time. Sooner or later, it will surely happen. If you think it won't happen, or won't cost millions of lives, or won't employ re-developed nukes eventually, please tell me why you think so. (No sarcasm…

I'm not really optimistic about this option, just a bit of wishful thinking about peace upon the world and such. OTOH, even with MAD we still have wars and probably much more than 100K people on average get killed in wars every year. Even with MAD, NATO is pushing conflict with Russia well beyond a proxy war at this point. MAD doesn't work if the world goes mad...

Re: US Department of Energy: Fusion Ignition Achieved

#973

Post by prvc »

Ancapistani wrote: post #102
prvc wrote: post #47

Earlier quoted context omitted.

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'…

It is an obvious necessary condition that input power < output power, however merely satisfying this could have no special practical significance for any design that could end up being devised. The obviousness of that condition is what makes this a PR accomplishment only.

Re: US Department of Energy: Fusion Ignition Achieved

#974

Post by trompetenaccoun »

hatsunearu wrote: post #948
bzbarsky wrote: post #932

Earlier quoted context omitted.

Heat and temperature are indeed not the same. For both the sun and a human on earth there are two processes going on: 1. Heat production per unit volume. 2. Heat loss per unit surface area. The volume to surface area ratio for the sun is much larger than for the human, for a minor reason (the sun is a sphere) and a major reason (the sun's linear size is much bigger). So the equilibrium temperature of the sun in the s…

Yeah, this is a morbid analogy but if you got a bunch of people enclosed in a small area, the people in the middle will get so hot they will heatstroke, even if it's freezing outside. See the recent Korean crushing disaster.

Don't give them ideas, harnessing people power would solve all the major problems. Overpopulation, global warming, energy crisis,... Reminds me of that 'Mitchell and Webb - Kill all the poor' sketch.

Re: US Department of Energy: Fusion Ignition Achieved

#975

Post by User23 »

jdhendrickson wrote: post #960
User23 wrote: post #941

Earlier quoted context omitted.

> 1. How does this research help address this problem? I see it the other way around, this problem makes me doubt that this research will ever actually lead anywhere, supposing it's even as good a result as it first appears. > 2. What are the sources for your opinion? It's a fact. And my source is dead tree media. I don't recall all the details, but there are some very finicky parts that go into a state of the art wa…

This is incorrect. Similar to the "we can't make concrete as good as the romans" line of woo. Caveat Emptor

I like how you topped off the Roman non sequitur with some Latin. Alas, it is correct. Here[1] is an article about "Fogbank."

[1] https://www.motherjones.com/politics/2009/05/fogbank-america...

Re: US Department of Energy: Fusion Ignition Achieved

#976

Post by pertymcpert »

vlovich123 wrote: post #906
pertymcpert wrote: post #833

Earlier quoted context omitted.

Uh because building fission reactors, despite being fairly safe, is still a risk compared to fusion? We don’t want to put fission reactors in every town, but we could one day with commercial fusion. And the sheer amount of energy we could harness would allow us to do insane things.

> despite being fairly safe, is still a risk compared to fusion I recommend you read up on the Gen IV reactor designs. They’re totally safe - meltdowns are impossible because of the way the reactor is built. If anything catastrophic happens, the reaction stops and can never get to a runaway reaction (physically impossible). Look up Gen 4 reactors. Those will be available before fusion even gets off the ground (and I’…

I answered why fusion would change the work in ways different to how fission changed the world.

> Look. I understand there are problems with fission reactors. They remain the only feasible way to generate nuclear power in the next 60-100 years at scale. Yes there are downsides and risks. However there’s one big upside vs fusion: it exists.

If you re-read the original comment, it supposed that fusion exists. You can't criticize something in development for not existing and use that as a point against why it won't be beneficial. That's circular reasoning.

> The advantages of fusion are safety, nuclear waste management, theoretical proliferation concerns.

Yeah, just nuclear waste management. No big deal.

> They remain the only feasible way to generate nuclear power in the next 60-100 years at scale.

You absolutely cannot predict with that level of certainty over 100 year time scales. You severely underestimate how much we can achieve over timescales as long as that.

Re: US Department of Energy: Fusion Ignition Achieved

#977

Post by Dylan16807 »

cloudhead wrote: post #885
eru wrote: post #793

Earlier quoted context omitted.

> [...], or the ginormous fusion of the sun. The sun actually has very little fusion per cubic metre or per kg. Per volume the core of the sun produces only a quarter of the heat of the human body (and per kg it's even less, owing to high density). That's why our fusion reactors can't just mimic stars, they have to far surpass them to be useful to us.

How is the sun so hot then?

One square inch of your skin has a couple inches of flesh behind it making heat.

One square inch of sun has billions of inches of hydrogen behind it making heat.

Re: US Department of Energy: Fusion Ignition Achieved

#978

Post by poopbutt7 »

diordiderot wrote: post #889
poopbutt7 wrote: post #812

Earlier quoted context omitted.

You are correct: this is the important point. Until this is actually powering homes at scale and competitive price- which, clearly from these numbers is a fantasy- developments in this field should be dismissed. It's embarrassing to see HN so excited about what's really quite the failure. (Sent from my ENIAC)

> ENIAC was the first programmable, electronic, general-purpose digital computer, completed in 1945.

And a huge waste of $400,000.

Re: US Department of Energy: Fusion Ignition Achieved

#979

Post by Dylan16807 »

moloch-hai wrote: post #819
elihu wrote: post #813

Earlier quoted context omitted.

> The fusion startups are spending down investors' money with zero possibility of payback (Helion conceivably excepted), because if they did get Q>1, they have no workable way to harness it. ITER will not even try to produce one watt-second of electricity. Its follow-on demo reactor won't start building until 2050, if not further delayed. You seem to be awfully certain of that. I'm not an expert in this area, but my…

"Some details"... Have you ever built anything? Driving steam turbines, even with other costs at zero, leaves you uncompetitive with renewables. But other costs would be very, very far from zero. Extracting the grams of tritium at PPB concentration dissolved in 1000 tons of FLiBe every day so you have fuel for tomorrow is an expensive job all by itself. Making a whole new reactor every year or two because it destroye…

> Driving steam turbines, even with other costs at zero, leaves you uncompetitive with renewables.

Everything gets beaten by renewables when they're at high output.

But renewables plus reliable storage costs a lot more, and there's no way it's cheaper than steam turbines attached to a bottomless source.

Re: US Department of Energy: Fusion Ignition Achieved

#980

Post by eru »

rbanffy wrote: post #903
eru wrote: post #794

Earlier quoted context omitted.

> [...], and I doubt it will ever compete with solar, wind, and storage. Maybe not on earth, but there are applications in deep space.

> Maybe not on earth, but there are applications in deep space. Depends on how long the interstellar craft is supposed to travel. If it's under 100 years, fission should be able to do the trick of keeping the craft warm and the lights on for the sealed ecosystem to function during the decades of coasting between stars. Fusion rockets would be more convenient than fission ones because you can store the hydrogen you ne…

> Depends on how long the interstellar craft is supposed to travel.

I didn't have (only) travel in mind. I was thinking of living between the stars.

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