Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

MIT-designed project achieves major advance toward fusion energy

news.mit.edu

Post reply on HN
Print view View original

301–310 of 438 posts

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

#301

Post by phscguy »

crazygringo wrote: post #145
phscguy wrote: post #32

Earlier quoted context omitted.

Yeah, any positive news on fusion progress and there always seems to be the same set of comments appear that are overwhelmingly critical of fusion development. Fusion is not well funded and imo has been let down by mismanagement of ITER, and despite this keeps making progress. I feel that fusion is one of humanity's best shots at actively reversing climate change, and it is disheartening to see such widespread pessim…

> I feel that fusion is one of humanity's best shots at actively reversing climate change Couldn't the same thing be said about current fission reactors? I get that fusion doesn't have the downsides of fission... but I'm also worried that people will be "scared" of fusion in the same way they're against GMO vegetables and irradiated fruits, totally irrationally...

Sadly no. While I think that it would work and probably be cheaper and easier than fusion, fission has an absolutely abysmal public image.

People are terrified of radiation, even if the danger is very low. This means it becomes prohibitively difficult and hence expensive to build and run a fission plant because safety has to be prioritized so heavily. That is even if permission is granted to build in the first place.

I think it is unlikely for irrational fear of fusion to become mainstream like it has with fission.

Because of this I think the barriers to fusion power are at this point lower than the barriers to scaling up fission power.

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

#302

Post by belorn »

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…

> Is anyone building fission reactors, or any kind of huge concrete building out in the ocean at all?

Yes, they are and it is a huge political issue in nearby countries.

https://en.wikipedia.org/wiki/Russian_floating_nuclear_power...

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

#303

Post by codethief »

roenxi wrote: post #299
codethief wrote: post #293

Earlier quoted context omitted.

I don't think it'll be easy . We would have the same (if not higher) energy consumption per capita on any other planet. And unless that planet is humongously large (which would also increase its surface-level gravity, thus rendering it uninhabitable), the relation between surface temperature and energy consumption will be similar[0]. Now there's only a finite number of planets in our solar system and leaving our sola…

We're talking a world where humanity has enough energy on tap that not only could it have feasibly evaporated the Pacific Ocean, but that it basically has evaporated the Pacific Ocean, as a side effect of doing something else. We can barely speculate about such a world, but interstellar travel would not be much of a challenge with that sort of energy abundance. We'll find a way.

> but interstellar travel would not be much of a challenge with that sort of energy abundance.

I don't think I agree.

1) The extremely high (but still finite) amount of energy required to evaporate the Pacific Ocean is still much less than the infinite energy you need to accelerate even one single space traveler to the speed of light. Infinity is weird.

Of course we won't be trying to reach the speed of light but the energy (and fuel) required to move half the species (so that the other half can stay on Earth/Mars/…) will still be significant.

2) My second argument was that the Stefan-Boltzmann law is just the same on board the space ship. And if we live there for generations, chances are our energy consumption per capita will be similar as on the planet we left, and so we will be running into similar issues with Stefan-Boltzmann's law. Sure, we can split up the passengers across multiple space ships and make each ship much bigger (to increase surface size) but not only will this increase the total mass and thus fuel required for the trip but we would probably still not achieve the (rather high) surface area per capita ratio that we have on Earth.

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

#304

Post by choeger »

ncmncm wrote: post #290
choeger wrote: post #269

Earlier quoted context omitted.

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…

"Just handed the money", my ass. Did you ever work in science? How to you even think that money should be distributed in scientific institutions? Everyone gets a share based on ... what? Their degree? Number of publications? Consensus by committee?

And for comparison, look what the ISS has brought us commercially: We have a fully commercial manned spaceflight planned for next week. That is a massive achievement without even considering all the scientific work on the station.

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

#305

Post by tuatoru »

AnthonyMouse wrote: post #262
tuatoru wrote: post #245

Earlier quoted context omitted.

> A major cost of the most utilized existing power plants (coal and natural gas) is fuel. Coal is dead. The competition is PV, and to a lesser extent wind. > Renewables don't need fuel but their construction cost is fully linear, you get no economies of scale. If you want twice as many solar panels then you need twice as much land. Yes, and you use odd bits of land close to consumption sites, many of which will have…

> 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…

Here, look: take case 11 from this study by Sargent and Lundy[1](PDF): an AP1000 fission reactor, 2.156GW, $6041/kW, swap out the fission reactor for fusion generation at $0, and show us how to get to $176/kW (a tenth the per-kW price of a small-scale PV plant with battery storage, case 25).

Also note the construction timetables: 72 months vs 18 months for PV.

1. EIA 2020, Capital Cost and Performance Estimates for Utility Scale Power Generating Technologies: https://www.eia.gov/analysis/studies/powerplants/capitalcost...

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

#306

Post by ben_w »

roenxi wrote: post #299
codethief wrote: post #293

Earlier quoted context omitted.

I don't think it'll be easy . We would have the same (if not higher) energy consumption per capita on any other planet. And unless that planet is humongously large (which would also increase its surface-level gravity, thus rendering it uninhabitable), the relation between surface temperature and energy consumption will be similar[0]. Now there's only a finite number of planets in our solar system and leaving our sola…

We're talking a world where humanity has enough energy on tap that not only could it have feasibly evaporated the Pacific Ocean, but that it basically has evaporated the Pacific Ocean, as a side effect of doing something else. We can barely speculate about such a world, but interstellar travel would not be much of a challenge with that sort of energy abundance. We'll find a way.

I believe the two of you are talking about different things.

The argument in the UCSD blog post linked above will apply to any finite system if you assume exponential growth in power use, and exponential beats cubic for expansion to other worlds (I’m assuming no FTL for a cubic limit to expansion).

Abundant power — be it from fusion or solar or quantum magic — does not actually need to guarantee eternal exponential growth of power use, but the absence of such growth would necessarily lead eventually to the absence of economic growth.

We can still have a SciFi future without that, it will just look different in a way our current society can’t properly envision (which I think is an unsurprising a claim to make even in the absence of the rest of this argument).

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

#307

Post by liamwire »

ncmncm wrote: post #146
causality0 wrote: post #61

Earlier quoted context omitted.

Are those calculations of net gain referring to the total energy generated, or the amount we can realistically capture and put to use?

The amount of this we can realistically put to use is, always and forever, exactly zero . The only useful outcome of any of this work is a generation of plasma-fluid physicists with practical experience. Pray we can find them something useful to do when the whole enterprise finally collapses.

You keep making these assertions, failing to back them up with anything other than hand-waving in the direction of entirely unrelated programs. You then respond to requests for citations, or even just an elaboration, with the near-verbatim ‘do your own research.’

Chiefly, how does that further the conversation? More pointedly, why should we listen to you?

Credentialism in this arena is valid, and what I currently see are multiple subject matter experts, albeit with a bias/incentive towards believing in themselves, versus you. Please substantiate your claims, or word them more carefully as to reflect them being conjecture.

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

#308

Post by ncmncm »

derac wrote: post #200
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…

Actually you can scale magnetic field stength or size to produce more power. SPARC (and later ARC) aims for the former with modern superconductor tech and is on track to potentially produce energy at Q~=11 by 2025.

I don't doubt it will produce plenty of of fast neutrons. Producing useful energy without destroying the most expensive parts of your reactor in the process is a whole other project. Doing it anywhere nearly as cheaply as overwhelmingly simpler systems whose costs are still in free fall is another, probably impossible project.

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

#309

Post by qPM9l3XJrF »

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."

What does fusion give us that existing nuclear power plant tech doesn't?

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

#310

Post by GordonS »

mcswell wrote: post #95
anonuser123456 wrote: post #17

Earlier quoted context omitted.

> What's the catch this time? This is D-T fusion. Which means you have to have T. Which currently comes from fission reactor and has a half life of 15 years. So the plan is to use a molten salt blanket with Be to breed T. But Be isn’t scalable for consumption, so maybe lead eventually. That’s probably do-able, it just slows down the rate new reactors can come online since Pb is not as good a neutron multiplier. Once…

"Hydrogen is very corrosive and hard to work with" Corrosive compared to what? You can put it in a rubber balloon and hand it to a kid. "T is radioactive hydrogen": True, it emits low energy beta radiation, which is an electron, and is stopped by a sheet of paper. I used to have a wrist watch with a tritium dial; I haven't died of cancer yet.

> Corrosive compared to what? You can put it in a rubber balloon and hand it to a kid.

I've never heard of hydrogen-filled balloons (at least not the kind of balloon you can hand to a kid) - we're you thinking of helium?

Post reply on HN