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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

#301

Post by bserge »

dougabug wrote: post #213
ClumsyPilot wrote: post #183

Earlier quoted context omitted.

I am really tired of this line - the taunami killed 18,500 people. The reactor incident killed no-one through radiation and 32 people through physical injuries. One failure of Banqiao Dam killed an estimated 240,000 people. That's more than all people who have ever died from anything to do with nuclear, reactors and bombs combined. Air pollution kills about 2,000 people every single day. Reactor incidents are like pl…

But the tsunami didn’t render large areas of land uninhabitable, as in the case of Chernobyl and Fukushima.

The nuclear incidents didn't, either. Decontamination of Okuma has been successful and residents are already returning.

Pripyat is an animal and vegetation haven. Really shows how dangerous our species is to the planet.

Point is, nuclear power plants, even the old ones, are nowhere near as dangerous as the media portrays them.

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

#302

Post by [deleted] »

tuatoru wrote: post #277
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.

> 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-rea…

[deleted]

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

#303

Post by justincormack »

pm90 wrote: post #266
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…

Not disagreeing with you, but it might still be ok. I don't believe early fission reactors were cost effective either. If we build a few with heavy subsidies and create an economy around them, we may get more commercial players involved, and a lot more investment dollars chasing the problem.

The early fission reactors were to make bombs not electricity. Large subsidies available there.

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

#304

Post by 317070 »

samatman wrote: post #167
Tossrock wrote: post #150

I wish these people the best, and I really hope they get a working fusion plant soon. That said, I can't resist sharing Admiral Rickover on academic reactors vs practical reactors: Important decisions about the future development of atomic power must frequently be made by people who do not necessarily have an intimate knowledge of the technical aspects of reactors. These people are, nonetheless, interested in what a…

It's a good contribution to the conversation, keeping in mind that Adm. Rickover wrote these words in 1953. Anyone could have said similar things about computers in 1953, and been just as correct. Are nuclear reactors computers? Of course not, and neither have practical reactors kept pace in development with practical computers. But neither is it inevitable that steady progress cannot grind down the latter set of cha…

In fusion, they can actually pinpoint exactly why it did not pan out as expected since 1953.

For fusion, you need to achieve a high temperature. So "thermal insulation" of the centre of the plasma from the edge of the plasma is really important. The nice thing is, that since charged particles move along magnetic field lines, and magnetic field lines never cross each other, the thermal insulation of plasma made from charged particles is enormous. That would imply it is really easy to achieve really high temperatures.

However, in 1953 they overestimated the enormous "thermal insulation" at higher temperatures by 10 orders of magnitude. That is a ratio of 1e10 between the expected and the actual value. It is still enormous, mind you, but not that enormous.

If that estimation had been correct, we would have had fusion by 1973. However, in that period it gradually became clear that fusion that way was not going to happen as people found lower and lower thermal insulations in their plasmas.

The same thing might have happened with semiconductors. What if the thermal noise were off by 10 orders of magnitude at smaller scales, compared to what was expected in 1953? Computing would not be where it is today, although it would definitely still be a good possibility if we were only pushing harder in circumventing the noise.

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

#305

Post by RobertoG »

jnxx wrote: post #275
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 r…

>> "Tritium, however, does NOT exist in nature"

Maybe I don't understand properly, but I'm watching the video linked in a previous comment (1) and around the minute 9:30 professor White says that "what comes into the plant is actually deuterium and lithium".

It seems he is saying that you need only an initial quantity of Tritium and then Helium and Lithium is used to created Tritium again. I suppose that it's what you refer as "breeding". He explain it as it's not a big deal.

(1) - https://news.ycombinator.com/item?id=24632653

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

#306

Post by tim333 »

willis936 wrote: post #291
tim333 wrote: post #279

Earlier quoted context omitted.

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.

Where are you getting that ITER budget range? From what I can tell, it is much closer to $20 billion. That’s for a project that began in the 80s and will finish in 2045. 20 billion over 60 years is a pittance compared to the 15+ TW the world spends on energy.

It was an estimate from the US department of energy https://www.nextbigfuture.com/2018/10/nextbigfuture-said-ite... which ITER dispute.

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

#307

Post by de_watcher »

nradov wrote: post #236
lowdose wrote: post #163

Earlier quoted context omitted.

Yes exactly, this is what Nassim Taleb writes about in Anti fragile. Bets with a known limited downside and the potential of an almost unlimited upside.

The upside is in no way unlimited. Even in the best case scenario, fusion power will be expensive. It might end up being useful for base load but it's unlikely to be cheaper than solar in most areas.

Assuming that you use it like before. But if you have a lot of power in one place you may think about using it for something like an orbital launch system.

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

#308

Post by nradov »

de_watcher wrote: post #307
nradov wrote: post #236

Earlier quoted context omitted.

The upside is in no way unlimited. Even in the best case scenario, fusion power will be expensive. It might end up being useful for base load but it's unlikely to be cheaper than solar in most areas.

Assuming that you use it like before. But if you have a lot of power in one place you may think about using it for something like an orbital launch system.

The power grid already allows us to have as much power in one place as we want.

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

#309

Post by pm90 »

justincormack wrote: post #303
pm90 wrote: post #266

Earlier quoted context omitted.

Not disagreeing with you, but it might still be ok. I don't believe early fission reactors were cost effective either. If we build a few with heavy subsidies and create an economy around them, we may get more commercial players involved, and a lot more investment dollars chasing the problem.

The early fission reactors were to make bombs not electricity. Large subsidies available there.

I think it was clear from context that I meant fission reactors designed for electricity production. These reactors are significantly different in design from reactors used for producing weapons grade, highly enriched fissile material, and required significant investment in its own right to develop safe, commercial reactors.

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

#310

Post by galangalalgol »

DennisP wrote: post #289
jnxx wrote: post #276

Earlier quoted context omitted.

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

We have plenty of lithium. All D-T fusion designs breed tritium from lithium, using the high-energy neutrons from the reaction.

I assume very little lithium is actually needed, will the dramatically increased demand from battery manufacturing affect feasibility?
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