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Can Nuclear Fusion Put the Brakes on Climate Change?

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Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#11

Post by scanny »

d_theorist wrote: post #8

I used to be so excited about fusion, but then I actually learned more about it. Perhaps I'm missing something, but the benefits over fission seem underwhelming. It's about the same cost on a per-megawatt basis. Modern fission plants are totally safe. Nuclear waste is basically a non-problem, especially with the most recent technology. And fission has the huge benefit of being a mature, proven technology. What's the…

> Modern fission plants are totally safe. Nuclear waste is basically a non-problem

Just removing that as part of the rhetoric around the tech makes fusion invaluable.

Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#13

Post by leephillips »

BitwiseFool wrote: post #9

In a fission reactor, I know the energy goes into the water, which creates steam and that turns a turbine. But it looks like fusion reactors use a near vacuum and high powered magnets. Once two atoms actually fuse, where does that energy "go"? Does the new helium atom just bounce around the containment unit? How do we actually extract meaningful energy from such a closed system? Edit: https://en.wikipedia.org/wiki/IT…

Heat is extracted to run a turbine, as with any reactor.

Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#14

Post by himinlomax »

Nuclear fission is good enough, available right now, causes much fewer deaths than the alternatives, does not pollute the atmosphere, and accidents are extremely rare and nowhere near as dangerous as they've been portrayed. To wit, Fukushima: 1 dead from the nuclear accident, compared to 10000 from the tsunami.

Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#15

Post by leephillips »

d_theorist wrote: post #8

I used to be so excited about fusion, but then I actually learned more about it. Perhaps I'm missing something, but the benefits over fission seem underwhelming. It's about the same cost on a per-megawatt basis. Modern fission plants are totally safe. Nuclear waste is basically a non-problem, especially with the most recent technology. And fission has the huge benefit of being a mature, proven technology. What's the…

It is not worth investing money in, because it will never supply grid power: http://progressive.org/op-eds/let-cut-our-losses-on-fusion-e...

Here is another physicist warning about the hype just a few days ago: http://backreaction.blogspot.com/2021/10/how-close-is-nuclea...

Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#16

Post by lacksconfidence »

leephillips wrote: post #13
BitwiseFool wrote: post #9

In a fission reactor, I know the energy goes into the water, which creates steam and that turns a turbine. But it looks like fusion reactors use a near vacuum and high powered magnets. Once two atoms actually fuse, where does that energy "go"? Does the new helium atom just bounce around the containment unit? How do we actually extract meaningful energy from such a closed system? Edit: https://en.wikipedia.org/wiki/IT…

Heat is extracted to run a turbine, as with any reactor.

Sure, but how? What physical processes are being used? Most of us can understand how hot fision encased in water turns to steam and runs a steam engine (even if the reality is still quite complex). But how does the thin-plasma get converted to steam?

Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#17

Post by skywal_l »

d_theorist wrote: post #8

I used to be so excited about fusion, but then I actually learned more about it. Perhaps I'm missing something, but the benefits over fission seem underwhelming. It's about the same cost on a per-megawatt basis. Modern fission plants are totally safe. Nuclear waste is basically a non-problem, especially with the most recent technology. And fission has the huge benefit of being a mature, proven technology. What's the…

Don't you think that the fact that you can use sea water as input and you get hydrogen as output is a huge advantage over fission?

Add to that the fact that there is no fukushima style meltdown in a fusion power plant. If something goes wrong, it just stops.

Finally, contrary to fission, fusion power plants will be able to adjust their power output as fast as gaz power plants. It takes months to turn on or off a fission power plant.

So yes, there is definitely a few benefits to fusion. And take a step back on the numbers. Look at how much we injected in banks in 2008. If it works (and indeed there is a risk they won't make it work and this is probably where the argument should be) the investment would be amortize over thousands of years...

Can you imaging a guy, 3000 years ago in China, complaining about spending money on a kiln to smelt that thing called iron?...

Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#18

Post by tambourine_man »

d_theorist wrote: post #8

I used to be so excited about fusion, but then I actually learned more about it. Perhaps I'm missing something, but the benefits over fission seem underwhelming. It's about the same cost on a per-megawatt basis. Modern fission plants are totally safe. Nuclear waste is basically a non-problem, especially with the most recent technology. And fission has the huge benefit of being a mature, proven technology. What's the…

>Modern fission plants are totally safe. Nuclear waste is basically a non-problem, especially with the most recent technology

Please elaborate on both. And I think we can all agree there's no such thing as totally safe, only risk management.

Re: Can Nuclear Fusion Put the Brakes on Climate Change?

#20

Post by someguyorother »

BitwiseFool wrote: post #9

In a fission reactor, I know the energy goes into the water, which creates steam and that turns a turbine. But it looks like fusion reactors use a near vacuum and high powered magnets. Once two atoms actually fuse, where does that energy "go"? Does the new helium atom just bounce around the containment unit? How do we actually extract meaningful energy from such a closed system? Edit: https://en.wikipedia.org/wiki/IT…

In the same way. Most proposed fusion systems use deuterium-tritium fusion where a significant amount of the energy is carried away as neutrons, so direct energy conversion wouldn't be possible anyway.

From the article you referenced:

> ITER will not produce enough heat to produce net electricity and therefore is not equipped with turbines to generate electricity. Instead, the heat produced by the fusion reactions will be vented.

So in a fusion plant, the particle energy would turn into heat (by the particles interacting with matter), this would heat up water (or some other carrying fluid), turning a turbine that produces electricity. See also https://en.wikipedia.org/wiki/DEMOnstration_Power_Plant which contains some diagrams showing just how that would be done.

More exotic reactions (e.g. p-B11) have been proposed, where almost no energy is in the form of neutrons. Theoretically, you could then use electrostatic devices to capture the energy directly without any of the mess with Carnot efficiency. However, getting p-B11 fusion going is much harder than d-t.

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