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ITER: World's largest nuclear fusion project begins assembly

bbc.co.uk

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Re: ITER: World's largest nuclear fusion project begins assembly

#111

Post by DubiousPusher »

dantillberg wrote: post #100
cwhiz wrote: post #88

Earlier quoted context omitted.

I would like to see some models on how solar power could work in northern cities, or honestly any city. The NYC metro area has over 23 million residents and there is essentially zero space for a solar farm. In the winter it's cloudy almost all day and there are only 9 hours of sunlight. Rooftop solar is an option but the models I have seen show a theoretical max around 1,200 MW which is about 1/30th of the NYC metro…

You could imagine building a globe-spanning power distribution network. Solar panels on one side of the planet could provide power at night on the other side of the planet.

I bet the power transportation cost and loss would be too significant.

Re: ITER: World's largest nuclear fusion project begins assembly

#112

Post by pengaru »

nharada wrote: post #20
usui wrote: post #7

I am going to need some help on this one as my knowledge on physics is limited: What makes scientists believe that the solution to nuclear fusion power is only a matter of scale? I desperately want nuclear fusion to work because nuclear power is the only realistic way to solve the looming energy crisis of the 21st century while still maintaining the same standard of living for everyone. It's also 500% more important…

There's a good talk here about why ITER is so large: https://www.youtube.com/watch?v=L0KuAx1COEk The idea is essentially that to get the parameters needed to make net energy with tokamaks, you need either very strong magnets or a large device. At the time of ITER's design, they used the strongest magnets they could find and then made the thing big enough to get the energy gain they wanted. The speaker of this talk ar…

I didn't watch the talk, maybe it's the same one, but I recall watching a talk about Tokomaks that said thanks to the development of high-temperature superconducting wire ITER is already an obsolete design.

Re: ITER: World's largest nuclear fusion project begins assembly

#113

Post by throwaway0a5e »

ClumsyPilot wrote: post #86
throwaway0a5e wrote: post #68

Earlier quoted context omitted.

Even if we deploy batteries, wind and solar in an amount needed to mitigate a climate change crisis, the amount of mining and industrial activity that would take would greatly poison our planet in other ways. In terms of "other stuff you need to do" per MW none of these come close to touching fission. Fusion, being much cleaner than fission would be a holy grail of clean cheap energy. I hope it only takes 50yr to fig…

What part of a wind turbine 'greatly poisons iur planet"? Its an electric generator on a mast. How is it more poisonos than any other industrial object or consumer device?

>What part of a wind turbine 'greatly poisons iur planet"?

The batteries they're going to be paired with unless some other storage tech becomes better or windmills become so cheap that we can use less storage or inefficient storage. The windmills themselves are mostly fine since they're just fiberglass, metals and concrete.

Mining for the things that go into batteries is just as destructive as the mining done for coal. It just happens in Asia so nobody cares. If you destroy the suitability of land for habitation or certain crops (likely by affecting the watershed) then you create many of the same problems climate change would/will cause. If you make mining less destructive to the environment batteries become more expensive hampering renewable adoption. It's a catch 22.

Don't get me wrong, it's better than fossil fuels and better than anything involving a solar panel (which has all the mining related dirtiness on the energy production side as well as the storage side) but compared to the bang for your buck you get by knocking atoms around it's a hell of a lot of industrial activity.

Re: ITER: World's largest nuclear fusion project begins assembly

#114

Post by 6nf »

clomond wrote: post #94
scythe wrote: post #53

Earlier quoted context omitted.

>This is just not true, there's no way you can say this. Solar costs are going down massively. Hydro is dirt cheap already. So renewables can absolutely be part of an energetic transition in the near future, while fusion is at best many decades away. So while I think fusion energy has the potential to transform energy generation, and by extent everything about our life, it's wrong to assume renewables aren't probably…

Important distinction here: nobody actually cares or wants power that is baseload. In some cases it can actually be a bad thing. The property you really want is “dispatchable”. There when you want it. Not when you don’t.

Yes sure you can break it down like that. At larger scales (e.g. interstate transmission lines) you have to aggregate and then becomes baseload + surge again. Individual users want dispatchable, cities or counties becomes baseload +.

Re: ITER: World's largest nuclear fusion project begins assembly

#115

Post by sedgjh23 »

6nf wrote: post #108
jjoonathan wrote: post #62

Earlier quoted context omitted.

Hydro is actually pretty bad in terms of big safety incidents (Banqiao: 171000 dead, Machchu: 5000 dead, South Fork: 2208 dead) and solar/wind have trouble beating nuclear on metrics like death/watt because you need lots of infrastructure per watt. Picture a few large cities with contractors running around every roof tending to solar panels and compare to a few experts at a single nuclear power plant. For the contrac…

Hydro's main problem is that it's just not available in most countries / areas. Solar's main problem is that it's not reliable everywhere. Try setting up solar in Chengdu and you'll find that there's just not enough cloud free days in the year to make it worthwhile. We need baseline power and renewables are not usually enough. If you're lucky enough to have a river or sunny climate then great, but that's not possible…

Is it windy?

Re: ITER: World's largest nuclear fusion project begins assembly

#116

Post by epistasis »

xupybd wrote: post #43
vosper wrote: post #29

Earlier quoted context omitted.

> nuclear power is the only realistic way to solve the looming energy crisis of the 21st century while still maintaining the same standard of living for everyone I assume by "energy crisis" you mean "how do we continue to generate energy while drastically decreasing climate effects"? Because if we're not worried about climate there's no looming energy crisis. There's plenty of oil, gas, and coal out there still. And…

As I understand it renewables and batteries have their own environmental impacts that can't be ignored. When comparing nuclear with renewables the impacts start to show nuclear as at least a good contender as the future power source. But large scale fusion might drastically lower energy costs. That could enable things like carbon capture.

"Can't be ignored" meaning what precisely? This is a phrase that sounds like pure FUD, and despite spending a lot of time trying to quantify where this supposed environmental damage comes from, I haven't been able to find anything of substance.

Similarly, I don't think there's much reason to believe that fission nor fusion will be able to compete with renewables on cost. Even if fusion is a completely free source of heat, you still need to convert heat to electricity with a steam turbine and it won't be long before renewables are cheaper than a steam turbine and cooling infrastructure on a free heat source.

People have this strange faith in fission and fusion as being cheap, at some point in the future, but nobody can ever explain why it will be cheap. What is the mechanism that could drive this along?

Solar is the current cheap electricity that will drive carbon capture. There are even startups that have plans for using atmospheric carbon capture to generate synthetic fuels, that plan to be profitable with the current cost curves of solar and the rest of the industrial process.

The world is a very different place than 20 years ago when it comes to technology, and I think it's time to re-evaluate the potential promise of fusion as an energy source. I don't think it has much promise for terrestrial power, but as always, I would love to have my skepticism conquered.

Re: ITER: World's largest nuclear fusion project begins assembly

#118

Post by ArtWomb »

petschge wrote: post #13
usui wrote: post #7

I am going to need some help on this one as my knowledge on physics is limited: What makes scientists believe that the solution to nuclear fusion power is only a matter of scale? I desperately want nuclear fusion to work because nuclear power is the only realistic way to solve the looming energy crisis of the 21st century while still maintaining the same standard of living for everyone. It's also 500% more important…

The simple answer is that the surface only goes up a factor of 4 if you increase the radius by a factor of 2, but the volume goes up by a factor of 8. So the ratio of (energy containing) volume to surface (where energy get's lost) if getting better with increasing size. There is of course much more complicated answers, all the way up to full-device simulations using gyrokinetic codes like Gene or Gkeyll that take mil…

Good answer. It's referred to as the Lawson criterion for those wishing a deeper dive:

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

Regarding simulations, plasma physics can in a very real sense be viewed as the predominant driver for supercomputing research and funding. Ratio of fusion budget allocations to total global energy demand remains woefully pitiful. On order of something like 30B / 100T or 0.03%.

Re: ITER: World's largest nuclear fusion project begins assembly

#119

Post by DubiousPusher »

petschge wrote: post #48
fabian2k wrote: post #38

Earlier quoted context omitted.

I wonder how much the possible magnet strength affects the design of a tokamak. There are very clear limits on the field strength you can achieve with classical superconductors, and I know e.g. in Nuclear Magnetic Resonance those limits had been almost hit maybe a decade ago or so. But very recently spectrometers based on new high-temperature superconductors have been delivered, so the technology seems to be far enou…

Yes that has a big impact. The quality of a tokamak (as meassured by the triple product density, temperature, and confinement time) goes up like B^3 (IF I remember correctly, I do plasma physics but not fusion stuff) and the fussion power goes up like B^4 or something like that. So larger magnetic fields help a lot. But back when ITER was designed we did not have such strong superconductors yet. PS: Google found DOI…

Is there a successor to iter already being worked out on paper that takes into account new developments?

Re: ITER: World's largest nuclear fusion project begins assembly

#120

Post by StanislavPetrov »

andrepd wrote: post #39
usui wrote: post #7

I am going to need some help on this one as my knowledge on physics is limited: What makes scientists believe that the solution to nuclear fusion power is only a matter of scale? I desperately want nuclear fusion to work because nuclear power is the only realistic way to solve the looming energy crisis of the 21st century while still maintaining the same standard of living for everyone. It's also 500% more important…

I'm also a fusion power fanboy but >nuclear power is the only realistic way to solve the looming energy crisis of the 21st century while still maintaining the same standard of living for everyone This is just not true, there's no way you can say this. Solar costs are going down massively. Hydro is dirt cheap already. So renewables can absolutely be part of an energetic transition in the near future, while fusion is a…

>>nuclear power is the only realistic way to solve the looming energy crisis of the 21st century while still maintaining the same standard of living for everyone

This is also not true if we dealt with the massive overpopulation of the earth instead of acting as its some sort of moral crisis not to stuff as many people as possible onto a planet with finite renewable resources.

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