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Compact nuclear fusion reactor is 'very likely to work,' studies suggest

nytimes.com

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Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#271

Post by Mvandenbergh »

tgsovlerkhgsel wrote: post #164
gorkish wrote: post #63

Earlier quoted context omitted.

Yep; the key technology that took magnetic confinement fusion from 'ITER will probably work' to 'Maybe we should just go ahead and skip ITER' is rebco tape. The problem is that all known superconducting materials known will lose their ability to superconduct when exposed to a sufficiently strong magnetic field. The large field strengths induce eddy currents in the material which disrupt the propagation of the cooper…

Would it be feasible to upgrade ITER into a much more powerful plant with the new magnets, or are they basically spending another 15 years building a huge thing that is already obsolete?

It's probably not feasible to upgrade it but apart from the magnets a lot of problems being solved for ITER (especially materials, tritium handling, and remote operations) will be useful for any Tokamak and indeed for any magnetic confinement fusion device.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#272

Post by de_watcher »

a1369209993 wrote: post #188
ElFitz wrote: post #137

Earlier quoted context omitted.

> this is still exciting given how anemic advancement in the fusion space has been for 50+ years. "Nuclear fusion. 30 years away since 1950" Joking aside. I too am glad to see some progress of any kind, and new (seemingly credible) initiatives being funded and pursued

To be fair, we have known how to build a working nuclear fusion power generator (probably with less than 30 years of construction) since the 1950s (see Project Orion); it's just a ridiculously huge construction/engineering project (basically a internal combustion engine powered by thermonuclear bombs).

Blocked by the slowness of the space industry.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#273

Post by baq »

mlindner wrote: post #71
avmich wrote: post #59

Earlier quoted context omitted.

It could be argued that ITER is actually quite important in learning how to deal with high technical complexity in general. Probably a good reason by itself to keep working on ITER, ISS is way simpler in comparison. https://en.wikipedia.org/wiki/ITER#Criticism "The project however was significantly delayed at the design stage as result of purposeful decision to decentralize its design and manufacturing among 35 parti…

In other words, ITER is a jobs project.

jobs == domain knowledge

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#274

Post by dbetteridge »

Robotbeat wrote: post #204
maccam94 wrote: post #199

Earlier quoted context omitted.

Timeline (in case you want to skip over some parts): 00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science 00:04:24 - presentation starts 00:06:00 - identifies breakthrough with REBCO magnets 00:07:25 - explains deuterium-tritium fusion 00:12:30 - basic metrics for reactor performance 00:17:15 - energy output of other previous fusion experiments 00:19:00 - examines ITER and the problems of its…

I think they're using Yttrium (i.e. YBCO), right? It's hard to find that info.

https://nationalmaglab.org/magnet-development/magnet-science...

Looks like they 'only' need to be at 4.2Kelvin as well to operate, which is a definite improvement

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#275

Post by jnxx »

physicsguy wrote: post #259

So, I'm a physicist, and I went to a number of talks from people involved with the JET fusion reactor over the years, though fusion is not my area. And my understanding is not that it's difficult to make plasma, or even build a reactor in particular that is the main problem (though instabilities can be problematic), but it's that the internal structure degrades very rapidly and becomes highly radioactive, because you…

Applied physicist here. The other thing is: Existing fusion concepts need to use a reaction between Deuterium and Tritium, otherwise it's just infeasible. Deuterium exists in nature and can be produced with some form of isotope separation.

Tritium, however, does NOT exist in nature, and can only be conceivably produced in three ways:

1. Inside thermonuclear bombs

2. In heavy-water reactors, e.g. CANDU design, which requires Uranium, so it is not fuel-independent and totally dependent on nuclear fission technology. Getting Tritium that way is also extremely, extremely expensive.

3. possibly, in a breeding blanket of a fusion reactor. This makes fusion technology reliant on breeding reactors which is much more complicated and has many completely unsolved questions in the materials part. Also, existing fission-breeding reactors are also less safe, for example, like the Japanese Monju plant, which was cooled with liquid sodium, a highly reactive metal, which got incensed in a fire. Fusion breeder reactors will probably also require something like sodium cooling because of the high energy densities required.

And the existing research projects like ITER have not even started to address these issues - they are purely plasma physics experiments.

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

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#276

Post by jnxx »

varjag wrote: post #260
physicsguy wrote: post #259

So, I'm a physicist, and I went to a number of talks from people involved with the JET fusion reactor over the years, though fusion is not my area. And my understanding is not that it's difficult to make plasma, or even build a reactor in particular that is the main problem (though instabilities can be problematic), but it's that the internal structure degrades very rapidly and becomes highly radioactive, because you…

That's a luxury problem at the moment. A fusion reactor that can sustain positive output operation for 5 years is still a dream.

It is a total show-stopper because you don't have the amount of Tritium to power such a reactor.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#277

Post by tuatoru »

Retric wrote: post #56
DataDaoDe wrote: post #48

Earlier quoted context omitted.

I couldn't agree more. Once you realize that energy is the fundamental unit which powers everything else in the economy, not only from every movement of ourselves to those of our machines as well, you realize the more we advance in our ability to produce more and more energy at cheaper and cheaper costs in increasingly reliable ways, the more we can accelerate, without exception, every other industry.

There is ~zero expectation in the scientific community that fusion is going to be cheap at scale. It might eventually be cheaper than fission due to several factors. But, even that’s looking a long way off.

> It might eventually be cheaper than fission due to several factors.

This surprises me, for a number of reasons.

A fission reactor can be operated safely by a bunch of people with baccalaureates, whereas a fusion reactor will need PhDs, as I understand things. Also, its capacity factor will not be as good as that of fission reactors.

The waste from fission reactors can be made pretty small by reprocessing and in-reactor transformations. The radioactive waste from fusion is whole reactor vessels, which are large and difficult to handle (=expensive).

At commercial scale fusion reactors need ancillary fission reactors to manufacture the tritium they require. So you have two reactors instead of one.

Other factors look similar, except that fusion will carry an investment risk premium because of its novelty and complexity.

So under equivalent regulatory regimes it seems to me that fusion would cost as much or more than fission.

Can you explain why it might eventually cost less?

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#278

Post by jnxx »

m0zg wrote: post #88
Retric wrote: post #56

Earlier quoted context omitted.

There is ~zero expectation in the scientific community that fusion is going to be cheap at scale. It might eventually be cheaper than fission due to several factors. But, even that’s looking a long way off.

How so? Unlimited, non-radioactive fuel and inherent safety of the system alone could tip this scale pretty severely in favor of fusion once it becomes energy-positive. And remember, once that happens, investment is going to be through the roof, which will accelerate progress. Either the "scientific community" (whatever that means) is either too pessimistic about this, or you've just made this up.

> Unlimited, non-radioactive fuel

Nuclear fusion in the existing designs absolutely needs Tritium as one component of fuel, and Tritium can so far only be produced in Uranium reactors, in very small quantities and at an extremely high price.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#279

Post by tim333 »

willis936 wrote: post #210
closetohome wrote: post #182

Earlier quoted context omitted.

> "Nuclear fusion. 30 years away since 1950" Those projections usually include the caveat "if properly funded" - https://i.imgur.com/3vYLQmm.png

I’m not sure why this is being downvoted. Reactor studies come out every decade and validate this study every time.

I'm not sure lack of money has been the main issue. ITER is projected to cost $22-$65 bn and still won't be able to produce practical power because the tech isn't up to it. It's only the discovery of REBCO magnets that has made the SPAC design perhaps possible.

Switching ITER to an updated design might be an idea.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#280

Post by jnxx »

isoprophlex wrote: post #233
Baeocystin wrote: post #77

Earlier quoted context omitted.

>The plasma heats up, but how do you turn that into useful electrical energy? I appreciate that many people are commenting 'you couple the plasma to a working fluid', but I think the original comment was more along the line of how you couple a confined plasma to a working fluid. By definition the plasma is in a hard vacuum, magnetically bottled. What, then, is the coupling method? Thermal photons escaping confinement…

You're right, I was curious about capturing the fusion products in some way and still being able to extract useful energy. I looked up the effects of neutron radiation on materials[]. Sounds like a hell of an engineering challenge to come up with a robust way of getting that energy out! Radiation damage to materials occurs as a result of the interaction of a [neutron] with a lattice atom in the material. The collisio…

> https://en.wikipedia.org/wiki/Monju_Nuclear_Power_Plant

Yep. And anything touched by the neutron flux would become radioactive if it captures neutrons. For example steel, normal steel contains carbon, carbon captures neutrons, so the steel becomes radioactive, and also brittle. And then you need wiring and insulation and coolant and pumps and all that.

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