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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

#231

Post by lopmotr »

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…

Is it really clear the fusion power, even if it's achieved, will actually be cheap enough to use? Sure, the fuel is almost free, but the fuel for solar, wind, and hydroelectric power is also free and that doesn't make them cheap. If we're not worried about cost, we could build enormous batteries using existing technology and use solar and wind to power everything. Fusion has to be cheaper than that, and judging by the cost of ITER, it doesn't seem obvious that it can achieve that.

Remember how nuclear fission was going to be "too cheap to meter"? Turned out it's expensive to build and operate the plants, regardless of how cheap the fuel is.

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

#232

Post by willis936 »

petschge wrote: post #28
jansan wrote: post #25

Earlier quoted context omitted.

I am not a physicist, but AFAIK the problem is to maintain the plasma in a steady state. This could mean that they will try to keep the plasma stable for 8 minutes until it collapses.

The characteristic frequencies in the plasma are much higher. Kilohertz and up. The steady state will be reached within seconds, so to the plasma 8 minutes is basically "infinity". But at that point the all the power that is leaking out of the plasma (50MW of heating times a Q of 10 implies that the plasma will output half a GW) will have heated the wall to the limit (and that is with active cooling of the walls). On…

Tokamaks need a changing current in the central solenoid. So while 8 minutes is infinity for a stellarator, there are important performance benchmarks at 8 seconds, 8 minutes, 8 hours, etc. You trade pulse length for ohmic heating.

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

#233

Post by korantu »

ClumsyPilot wrote: post #227
korantu wrote: post #211

Earlier quoted context omitted.

nuclear energy density is derived from e=mc2, so fusion/fission are in the same ballpark. Current accepted way is to build solar/wind and redesign grid to deal with intermittency. Solar and wind are even more energy diluted than fossil fuel, they take 500 times more space, more land out of nature/alternative uses. Nuclear has already demonstrated that it can decarbonise industrial economy up to 80%, see France. and t…

All for nuclear, but the amount of land used is higely exadurated. It is actually totally trivial if you run the numbers. In reality >90% of worlds valuable land use is farming. Factories, cities, houses, etc. all hardly matter.

Well, one example. I live in Singapore, and for it to become energy independent, it would need a square kilometer for a nuclear plant. To achieve the same with solar, you need to pave the whole country with solar panels.

Besides, to make these solar panels you need to spend energy too. and EROI for advanced solar is about 20, where for nuclear it is 80+.

I think people should stop using nature when they can get the same/better results without using it/using several orders of magnitude less of it.

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

#236

Post by perl4ever »

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…

Indeed, we know that a fusion reactor will work if scaled up to about 1.4 x 10^27 cubic meters...

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

#237

Post by philipkglass »

worik wrote: post #191
arkh wrote: post #129

Earlier quoted context omitted.

> But (almost) everyone would be opposed to a fission plant or nuclear waste facility next door - and rightfully so. Reading this kind of debate from France is a good laugh. If you're interested you can check where our electricity comes from here: https://www.rte-france.com/eco2mix/la-production-delectricit... (between 60 and 70 percent of nuclear energy today).

Because France was desperate to have its own nuclear weapons. It was not economic for them either (tho back in the day it displaced coal - try having a coal plant next door)

France's nuclear power program actually displaced oil. France had a lot of oil fired electric power plants in the 1960s when it was a cheap fuel. As a reaction to the oil price shocks of the 1970s, France committed to the "Messmer Plan" for nuclear electricity:

https://en.wikipedia.org/wiki/Nuclear_power_in_France#Messme...

France demonstrated its first fission bomb in 1960 and its first thermonuclear bomb in 1968:

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

The 1970s and 1980s build up of nuclear power in France had nothing to do with desperation to have its own nuclear weapons. France already had them before the Messmer Plan.

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

#238

Post by perl4ever »

ClumsyPilot wrote: post #203
worik wrote: post #189

Earlier quoted context omitted.

Pie in the sky when you die....

Says the man living in a world plagued by short termism, where companies forsake their future to improve their quarterly report, where we have condemned generations to suffer climate change just so that we could have 15% cheaper electricity and enjoy oversized cars. This going further down this path only lead to misery

Given that interest rates in developed countries are generally lower than in all of history, and mind-boggling amounts of surplus capital are being deployed by companies like Amazon, Softbank, Tesla, etc., it seems to me that the world is less "plagued by short termism" than any time in the last 13 billion years.

I'm not debating your assessment in an absolute sense, or the direction that resources are deployed, I'm just saying relatively speaking, the world has been approaching an asymptote, so how far does it have to go to be enough? At what point does some disaster that we weren't expecting happen that proves we went too far in being future oriented? Like, I dunno, an actual plague?

Edit: I meant this to express something more than just another "well actually" comment - I think COVID-19 really raises existential questions about whether people in the wealthy countries have gone too far in a future orientation, as if everything was certain and we and our civilization were all immortal. It may not make a bit of difference for some, but I observe it's changing a lot of people's outlooks. Something that has stuck in my mind is how plastic bags were banned in my area just before the pandemic hit, and whether or not there was an actual repeal, everyone has brought them back. Is this something to lament, to cheer, or just to observe and contemplate? If everything is bad, is anything?

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

#239

Post by galvin »

godelski wrote: post #181
valuearb wrote: post #164

Earlier quoted context omitted.

My software startup was a huge beneficiary of the SSC cancellation, it freed up a nuclear physicist to write graphics software for us, which became one of our biggest products. I’m in favor of pursuing basic research, but there is always a cost. When you take a group of your smartest people and focus them on non-economic activities, the economy loses something.

I think you're over simplifying things with the example. There's 2 major factors that I see. 1) It is unknown what economic impact that the SSC would have had. It could produced more value or less than that which you and similar industries contributed to from the benefit of these scientists. A search shows that without accounting for the impact of the fundamental science, CERN's revenues exceed the costs by ~3bn euro…

Regarding CERN, it's probably too obvious but I can't help but mention Tim Berners-Lee's work.

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

#240

Post by Retric »

jjoonathan wrote: post #62
andrepd wrote: post #39

Earlier quoted context omitted.

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…

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 also directly saves lives by reducing flooding and indirectly via clean water. On net world wide hydroelectric dams have saved more lives directly than they have cost from dam failures. Which is unique among all energy sources. For context: https://en.wikipedia.org/wiki/List_of_deadliest_floods

As to nuclear, it’s horribly expensive when you try to scale it. France was regularly exporting and importing vast amounts of electricity to other countries and their power plant utilization was still 10% below the US etc. That directly equated to significantly higher prices.

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