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U.S. physicists rally around plan to build fusion power plant

sciencemag.org

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Re: U.S. physicists rally around plan to build fusion power plant

#141

Post by pfdietz »

free_rms wrote: post #20
wcarss wrote: post #12

Serious question: how does an article like this get written without mentioning SPARC[1] once? They're hardly secretive, they're MIT's people, they're moving on a plan to get results in ~5 years, and they're talking about the same kind of things: tokamaks, better computer modeling, and easier to make higher temperature superconductors for stronger magnets. I'm just a layperson, I only know pop science level stuff here…

God I wish we could Manhattan Project this shit. I'm a layman too but I get the impression that the theory is basically there and we just need to figure out the engineering. That's a solvable problem with lots of money and lots of teams. Are we going to wait until the sea level rises 20 feet and then say, geez, compared to the costs this imposed, fusion would have been easy?

Fission was a fundamentally easier problem than fusion. The equivalent of ignition was achieved in 1942 after one year of effort.

Re: U.S. physicists rally around plan to build fusion power plant

#142

Post by joncrane »

willis936 wrote: post #134
ncmncm wrote: post #130

Earlier quoted context omitted.

Yes, yes we are at an inflection point. But maybe not the kind you are thinking of. There will never be a commercial tokamak power plant. There has never, at any time, been any reasonable expectation of getting practical, commercial power from magnetic-confinement hot-neutron fusion. Renewables, with practical energy storage, will always be much, much cheaper than fusion could ever have been, even if it could be made…

>”Break-even" is nowhere near enough to get practical power out, because the energy extraction process must be so inefficient, with two stages of heat exchange before you get a working fluid you can run through your turbine. Correction: break-even is most of the way to a working plant. A “burning fusion plasma” is one that self heats. The plant requires very little power when the plasma is supplying most of its own h…

Liquid lithium wall blanket? I've heard the use of Lithium as a tritium breeder (which is important, assuming we're committed to duterium-tritium fusion), but never as a liquid. it makes sense though because in that case you don't have to completely disassemble the tokamak and replace the neutron blanket every few years(?). But again the technology to completely coat the inside of the tokamak in an even layer of liquid lithium has got to be daunting. What goes between the lithium and the plasma?

Re: U.S. physicists rally around plan to build fusion power plant

#143

Post by pfdietz »

willis936 wrote: post #135
yread wrote: post #109

Earlier quoted context omitted.

I always thought NIF is just a facade for weapons research, that there is no way to make it energy positive

It is. Their fusion power research program is essentially retired and it operates as a nuclear stockpile steward research facility.

It was end of LIFEd?

Re: U.S. physicists rally around plan to build fusion power plant

#144

Post by xnyan »

pontifier wrote: post #69

Ok, say I've got a new design for a fusion reactor, but it takes me 5 years to convince anyone that it's worth investigating. Fusion power has been set back 5 years. Someone please help me evaluate my design. Please! http://www.DDPROfusion.com

>Someone please help me evaluate my design.

Have you submitted your research for peer review, and if not, why?

Re: U.S. physicists rally around plan to build fusion power plant

#145

Post by ars »

xyzzyz wrote: post #88
01100011 wrote: post #82

Earlier quoted context omitted.

Aren't you implying, intentionally or not, that a "Manhattan Project" level of expenditure, $25 billion, is enough to make meaningful progress towards commercial fusion energy production? I don't think that is a given.

The implication is rather that we’ve grown much more inept when it comes to getting things done.

Or because all the low hanging fruit is plucked.

Re: U.S. physicists rally around plan to build fusion power plant

#146

Post by wil421 »

Seanambers wrote: post #123
logicchains wrote: post #60

Earlier quoted context omitted.

>God I wish we could Manhattan Project this shit. Interesting point of reference: the Manhattan project cost around around $25 billion in today's dollars. The US government spent at least $6 trillion on the coronavirus response, which could buy 200 Manhattan Projects. Coronavirus will kill around a million people this year at most; air pollution kills around five million per year (and sea level rises could kill a lot…

Interestingly enough, the most expensive program was The B-29 bomber program, which cost 50% more than the Manhattan project. Then one B-29 had an emergency landing in Sovjet and the soviets reversed engineered it into the TU-4. Tu-94 which is still flying is a newer scaled up version of this. It's amazing how much of the innovation the U.S did in the 1940s ended up in others hands(the bomb, B-29). The world would pr…

The physicists knew an atomic bomb was possible the US just did it fist. I am sure secrets got out that helped the Soviets create one but I think they would've created one regardless.

Re: U.S. physicists rally around plan to build fusion power plant

#147

Post by willis936 »

joncrane wrote: post #142
willis936 wrote: post #134

Earlier quoted context omitted.

>”Break-even" is nowhere near enough to get practical power out, because the energy extraction process must be so inefficient, with two stages of heat exchange before you get a working fluid you can run through your turbine. Correction: break-even is most of the way to a working plant. A “burning fusion plasma” is one that self heats. The plant requires very little power when the plasma is supplying most of its own h…

Liquid lithium wall blanket? I've heard the use of Lithium as a tritium breeder (which is important, assuming we're committed to duterium-tritium fusion), but never as a liquid. it makes sense though because in that case you don't have to completely disassemble the tokamak and replace the neutron blanket every few years(?). But again the technology to completely coat the inside of the tokamak in an even layer of liqu…

Beryllium coated tungsten and a copper-tungsten weave. This is still a hot area of research. It will be part of the research done at ITER and DTT (Divertor Tokamak Test facility).

Re: U.S. physicists rally around plan to build fusion power plant

#148

Post by pfdietz »

acidburnNSA wrote: post #51
Hasz wrote: post #49

Earlier quoted context omitted.

No one is giving you numbers for why this is wrong, so let me ballpark. Typical solar irradiance is 1000W/m^2. Mean sunshine hours where I live is 3000hrs/y. Assuming 100% efficiency, 100% solar irradiance, perfect angle etc for those 3000hours, we get ~10^10J of energy. Those are bad assumptions, but very generous. In a gram of deuterium, per e=mc^2, we get ~10^12J. There is 100x more energy in a single gram of dete…

If energy density were proportional to cost, nuclear fission would already be dominating by a factor of 2,000,000x over fracked gas and coal. The reality is that complexities of systems needed in energy conversions end up coming into play. Getting net energy out of fusion was done in the 1950s (explosively, but still). Even given sustained controlled fusion, you still have to build a power plant around it and 'break…

Right. The energy density argument is obviously wrong, and I marvel that people can still make it with a straight face.

Re: U.S. physicists rally around plan to build fusion power plant

#149

Post by fennecfoxen »

olau wrote: post #110
free_rms wrote: post #20

Earlier quoted context omitted.

God I wish we could Manhattan Project this shit. I'm a layman too but I get the impression that the theory is basically there and we just need to figure out the engineering. That's a solvable problem with lots of money and lots of teams. Are we going to wait until the sea level rises 20 feet and then say, geez, compared to the costs this imposed, fusion would have been easy?

Fusion is not going to solve the sea level rise problem. You can see this by comparing it to fission. Fission fuels is not expensive on a kWh base, so cheaper fuel is not really a big advantage. Fusion plants produce radioactive waste too (perhaps less?), so you don't save yourself from that headache. Which isn't actually that big of a problem either, even if the costs are probably underestimated for fission plants.…

Fission is too expensive because everyone tried to get economies of scale at big complex custom-built one-off plants. Those who see hope for fission look to get economies of scale with a modular approach, mass-producing simple, small, reactors, shipping them from the factory to the site on trucks, and attaching them to the grid.

I am not qualified to assess whether that hope is well-founded, but there are real differences in the approach.

Re: U.S. physicists rally around plan to build fusion power plant

#150

Post by pfdietz »

mrfusion wrote: post #10
tahoeskibum wrote: post #4

I think that solar/wind + battery (e.g. Tesla Megapack) will make fusion irrelevant.

Still very useful for space travel, colonies, perhaps even cargo vessels.

DT fusion is bad for space travel because the reactors are too large. It has no advantage in space over fission.
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