MIT-designed project achieves major advance toward fusion energy • Hacker News Board

Re: MIT-designed project achieves major advance toward fusion energy

#281

Post by codethief » Thu, Sep 09, 2021, 7:19 AM UTC

mchusma wrote: post #112

dfdx wrote: post #34

Plenty of skepticism in these comments. I've been following CFS for a while and can present a point of view for why this time might be different. Fusion energy was actually making rapid progress in the latter half of the twentieth century, going from almost no power output in the fifties and sixties to a power output equal to 67% of input power with the JET reactor in 1997. By the eighties there was plenty of experim…

You are right, people who flippantly dismiss fusion just don't understand it. -Fusion has made consistent improvement, roughly in line with expectations for the level of investment (20 years away predictions were considering if we invested massively, which we did not). - Fusion is in theory something that could give us true energy abundance. Want to just desalinate water like crazy? Want to extract gigatons of carbon…

> Fusion is in theory something that could give us true energy abundance.

Well, at least for a few hundred years but then:

> if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrared) radiation. We understand the phenomenon perfectly well, and can predict the surface temperature of the planet as a function of how much energy the human race produces. The upshot is that at a 2.3% growth rate [in energy consumption] (conveniently chosen to represent a 10× increase every century), we would reach boiling temperature in about 400 years. […] And this statement is independent of technology. Even if we don’t have a name for the energy source yet, as long as it obeys thermodynamics, we cook ourselves with perpetual energy increase.

Source: https://dothemath.ucsd.edu/2012/04/economist-meets-physicist...

Re: MIT-designed project achieves major advance toward fusion energy

#282

Post by roenxi » Thu, Sep 09, 2021, 7:22 AM UTC

codethief wrote: post #281

mchusma wrote: post #112

Earlier quoted context omitted.

You are right, people who flippantly dismiss fusion just don't understand it. -Fusion has made consistent improvement, roughly in line with expectations for the level of investment (20 years away predictions were considering if we invested massively, which we did not). - Fusion is in theory something that could give us true energy abundance. Want to just desalinate water like crazy? Want to extract gigatons of carbon…

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

If there is enough ambient energy to literally boil the seas then we're probably going to find it easy enough to leave the earth and go somewhere cooler.

Re: MIT-designed project achieves major advance toward fusion energy

#283

Post by tsimionescu » Thu, Sep 09, 2021, 7:24 AM UTC

godelski wrote: post #224

tuatoru wrote: post #218

Earlier quoted context omitted.

Yeah, really, how? Fusion power plants still need land, buildings, generators, switchyards, wire, own power consumption, environmental impact reports, planning permits, regulations, inspections, and all the rest. And they need exotic materials and weird engineering in their construction. Really: how does fusion get us to ~1% (correction: ~5%) of current power prices? I've never seen a convincing explanation. Usually…

Theoretically? Pure brute force. Fusion just generates that much electricity that it has the potential to be insanely profitable. There's a lot of ifs, but there's a good reason to bet big on it.

People often make the mistake of looking at the reaction energy of fusion, and comparing that with fission or burning fossil fuels.

But the majority of the reaction energy is carried away by high-speed neutrons, which are pure waste - they can't be captured by magnetic fields, they are heavy and penetrate almost any material, leaving holes behind that make the structure brittle, and when they do get absorbed, they make the atom that absorbed them unstable, turning the material radioactive.

So, at least as long as we use neutri-producing fusion (and any realistic fusion reactor has to) the actually usable energy is not that impressive compared to fission.

Re: MIT-designed project achieves major advance toward fusion energy

#284

Post by veltas » Thu, Sep 09, 2021, 7:25 AM UTC

codethief wrote: post #281

mchusma wrote: post #112

Earlier quoted context omitted.

You are right, people who flippantly dismiss fusion just don't understand it. -Fusion has made consistent improvement, roughly in line with expectations for the level of investment (20 years away predictions were considering if we invested massively, which we did not). - Fusion is in theory something that could give us true energy abundance. Want to just desalinate water like crazy? Want to extract gigatons of carbon…

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

How do we know that global temp rise isn't just due to energy usage? I mean "does that calculation fit at all?", not "carbon dioxide is fake".

Re: MIT-designed project achieves major advance toward fusion energy

#285

Post by maccam94 » Thu, Sep 09, 2021, 7:28 AM UTC

tsimionescu wrote: post #265

dfdx wrote: post #34

Plenty of skepticism in these comments. I've been following CFS for a while and can present a point of view for why this time might be different. Fusion energy was actually making rapid progress in the latter half of the twentieth century, going from almost no power output in the fifties and sixties to a power output equal to 67% of input power with the JET reactor in 1997. By the eighties there was plenty of experim…

There are still fundamental problems with fusion reactors that are unlikely to make them economically viable, or even carbon neutral. Most notably, the extreme temperatures, hydrogen pumping, and high-energy neutron bombardment mean that, even with liquid metal blankets, the reactors will very quickly become brittle, probably not lasting more than a year or two. Since neutron bombardment also turns any material radio…

CFS has plans for swappable vacuum chambers (1 year lifespan) and the liquid blanket will protect the magnets for a 10 year lifespan.

This talk by the MIT Nuclear Science department head explains the whole rationale behind ARC/SPARC, and this timestamp is where he starts talking about maintenance and the neutron blanket (5 minutes later): https://www.youtube.com/watch?v=KkpqA8yG9T4&t=2400s

Re: MIT-designed project achieves major advance toward fusion energy

#286

Post by ncmncm » Thu, Sep 09, 2021, 7:32 AM UTC

craftinator wrote: post #187

ncmncm wrote: post #182

Earlier quoted context omitted.

Nor ever produce so much as one solitary erg to flash an LED.

You do seem to be going on quite the hatefest of Fusion, but continue to add nothing to the conversation, including sources of information. So how much energy is in an erg?

3000 ergs is enough to flash an LED.

When you have no turbine or any other means to extract power from a heat source, none gets extracted. Do you need a source for that?

Re: MIT-designed project achieves major advance toward fusion energy

#287

Post by jabl » Thu, Sep 09, 2021, 7:35 AM UTC

veltas wrote: post #284

codethief wrote: post #281

Earlier quoted context omitted.

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

How do we know that global temp rise isn't just due to energy usage? I mean "does that calculation fit at all?", not "carbon dioxide is fake".

Because we know that so far humanity's energy use is so small that the heating effect via increased blackbody radiation equilibrium temperature is utterly dwarfed by what mainstream climate focuses on, like GHG gasses.

Re: MIT-designed project achieves major advance toward fusion energy

#288

Post by AnthonyMouse » Thu, Sep 09, 2021, 7:39 AM UTC

tsimionescu wrote: post #280

AnthonyMouse wrote: post #262

Earlier quoted context omitted.

> Coal is dead. The competition is PV, and to a lesser extent wind. Coal is dying but it's still ~20% of US generation. The natural gas share of US generation has gone up . > Yes, and you use odd bits of land close to consumption sites, many of which will have simultaneous use for other purposes. Until you run out of those and then your costs increase worse than linearly because you have to start using more expensive…

> This is the opposite of how economies of scale work. If you make something bigger, the variable costs scale linearly and the fixed costs stay the same but are amortized over more units. That's not how construction works. Past some small scale, construction cost scales quadratically or worse with size. Building a 100m tall sky scraper is not 10 times as expensive as building a 10m tall 3-story house - it is at least…

> Building a 100m tall sky scraper is not 10 times as expensive as building a 10m tall 3-story house - it is at least a hundred times more.

Most of your cost difference is that a commercial building isn't just taller than a house, it's also wider. Instead of taking up a third of the lot, it uses the whole thing, and then has 30 times more interior space despite being only 10 times taller. They're also built to commercial building standards which are more expensive to meet.

The costs start getting non-linear when you get into extremely tall buildings that pose special engineering challenges, but nobody is talking about building a fusion reactor into a skyscraper.

> I have no idea why you even imagine that it's possible at all to construct a nuclear power plant out in the ocean. There is certainly no precedent for anything even close to that.

Nuclear submarines survive the ocean just fine.

Re: MIT-designed project achieves major advance toward fusion energy

#289

Post by ifdefdebug » Thu, Sep 09, 2021, 7:42 AM UTC

codethief wrote: post #281

mchusma wrote: post #112

Earlier quoted context omitted.

You are right, people who flippantly dismiss fusion just don't understand it. -Fusion has made consistent improvement, roughly in line with expectations for the level of investment (20 years away predictions were considering if we invested massively, which we did not). - Fusion is in theory something that could give us true energy abundance. Want to just desalinate water like crazy? Want to extract gigatons of carbon…

> Fusion is in theory something that could give us true energy abundance. Well, at least for a few hundred years but then: > if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrar…

Well if we transform solar into electric then into motion or bound carbon, that should actually help reduce the heat balance?

Re: MIT-designed project achieves major advance toward fusion energy

#290

Post by ncmncm » Thu, Sep 09, 2021, 7:44 AM UTC

choeger wrote: post #269

ncmncm wrote: post #120

Earlier quoted context omitted.

ITER is a victim of a process seen frequently in large public-works projects, but particularly those where no one understands what anything really should cost, and where there is no practical deadline for completion. It is worst when there is no expected utility when it is done. We see it lately in the numerous military procurements (particularly the F-35 program), in NASA's SLS rocket, in California's bullet train t…

That's some hating BS right there. ITER might fail to produce economically viable fusion energy, but it certainly won't fail to produce a massive amount of scientific and engineering innovation. The sole fact that such a scientific undertaking can be done internationally, over decades, is a great thing considering the global problems we face. Yes, ITER doesn't follow the USA economic ideology of "much", "cheap", and…

ISS is an apt comparison. Its apparent purpose while the Shuttle was flying was to be a place the Shuttle could get to. What it is for now is anybody's guess. In just a few years it will be a celestial light show, somewhere.

I have no doubt that plasma fluid physicists will learn a great deal from trying to get ITER lit up. Just handed the money, they could have learned a thousand times more, and maybe even achieved practical D/H-3 fusion propulsion for spacecraft. But that will not happen at ITER.