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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

#291

Post by willis936 »

tim333 wrote: post #279
willis936 wrote: post #210

Earlier quoted context omitted.

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.

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.

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

#292

Post by pfdietz »

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…

> the heavy metals that are often put into steel to increase strength are highly fissionable

Not fissionable, but many are unacceptable due to formation of long lived activtion products.

One additional problem with the alloys used is the degradation of their mechanical properties under radiation exposure. They tend to become brittle.

Testing any of these materials will require something close to a working fusion reactor (nothing else duplicates the neutron environment), but that will require the materials. Working around this loop of circular development dependency will be time consuming.

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

#293

Post by sergeykish »

pleasedontbanme wrote: post #201
Retric wrote: post #185

Earlier quoted context omitted.

Deuterium is a stable isotope, but Tritium’s half life is only 12.32 years making it quite radioactive. There is significant effort put into using lithium blankets to create tritium at which point arguably the fuels are lithium and deuterium. But that’s also going to require irradiate the relevant equipment.

Tritium is worth $30,000 a gram.

Lithium carbonate Li2CO3 is worth $6.75/kg

https://www.fastmarkets.com/commodities/industrial-minerals/...

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

#294

Post by FriskyAlter »

drran wrote: post #256
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…

Tsunami and earthquakes are not man generated events, so we can dismiss them. Yes, they killed a lot of people, but cancer kills even more: about 10 millions per year. In part, cancer is caused by contamination of food by radionuclides from reactor leaks (Chornobyl) and nuclear bomb testing.

Yes, cancer did not exist before nuclear. We can blame cancer on nuclear plants and bombs. That's quality commentary.

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

#295

Post by pfdietz »

fghorow wrote: post #165
m0zg wrote: post #88

Earlier quoted context omitted.

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.

"Non Radioactive Fuel" is technically correct. But. The fusion produces neutrons.[1] That means that at least some parts of the infrastructure can't avoid becoming radioactive. Decommissioning -- at the very least -- is still a problem. Any actual nuclear physicists want to chime in here? [1]Yes, the concept of "Aneutronic fusion" exists: https://en.wikipedia.org/wiki/Aneutronic_fusion >. But read the parts about the…

Tritium is in the fuel, and it's quite radioactive.

A 1 GW(e) reactor would burn enough tritium in a year that, if that quantity were to be released into the environment, it could contaminate 2 months worth of the flow of the Mississippi River above the legal limit for drinking water.

Tritium containment at a fusion reactor will have to be damned near perfect. This will be a major problem, as tritium permeates through all sorts of things (for example, plastic seals on containment penetrations cannot be used).

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

#296

Post by willis936 »

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…

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

Section 3.2 Test Blanket Module (TBM) Testing Program in ITER

https://www.iter.org/doc/www/content/com/Lists/ITER%20Techni...

Look even closer at the fusion energy research community and you will find a lot of work has already gone into this problem. Assuming physicists sit on their thumbs is a bad bet.

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

#297

Post by ArnoVW »

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).

Orion was essentially an "external combustion engine". I.e. you have a huge piston that is driven by repeated explosion of nuclear bombs. With a spring mecanism to even out the whallops. And no "engine block" around it.

It did not generate electricity, and given the discrete/pulsed nature of the mecanism, I have a hard time seeing how you would "even out" the output, should you decide (somehow) to attach it to a generator. Let alone imagining how you would transport said electricity back to earth.

Because, don't forget, it was possible to have an external combusion engine because it was in space. Even by 50's standards, the project was judged a non-starter for atmospheric flight, from environmental standards point-of-view.

The project itself was in theory viable for it's original objective (space travel), but highly impractical. It requires massive, robust structures (read 'heavy') that can resist very high impacts. Not a problem once you're into space, but you have to get it into space first. And no-one will let you blow up a couple of scores of nukes in the atmosphere, on a recurring basis. The thought of launching hundreds of nukes into space to a ship built in orbit is not exactly an easy proposition either.

Still, should an extinction-level meteor ever show it's face, it would be useful.

For fun : some original footage of the prototypes in flight (using high explosives) https://www.youtube.com/watch?v=Q8Sv5y6iHUM

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

#298

Post by Retric »

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…

Significantly less security concerns. No need for a massive containment vessel or massive redundant safety systems. Likely cheaper fuel and no long term high level nuclear waste. A smaller percentage of the reactor becomes contaminated. Lower insurance costs.

D is already cheap and even used by fission reactors. Extracting T from the blanket is presumably inexpensive, and one of the things ITER will test, but that’s an unknown. https://en.wikipedia.org/wiki/Breeding_blanket The real question is how expensive the physical reactor is going to be to build and maintain and does that offset the other savings. It’s expected for that cost to drop over time which is why it’s possible to eventually be cheaper than fission.

Finally, DT is easiest to achieve at a 50/50 ratio but DD fusion still takes place. So a lower mix of T is viable once very high Q values are possible, thus eventually zero T designs should be viable.

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

#299

Post by willis936 »

simonh wrote: post #112
Florin_Andrei wrote: post #40

Earlier quoted context omitted.

> this is still exciting given how anemic advancement in the fusion space has been for 50+ years At the top of my list for when I'll be king for a day is - massive, national-scale investments (think: reaching towards one percent of GDP) in fusion research. This is a major roadblock, but things look awesome on the other side. We just need to get our stuff together to hop over this fence somehow.

I think it’s generally very hard to force technological progress along by just throwing money at it. Let’s suppose this proposal works out, ITER will become a very expensive boondoggle. A technological dead end. But if you’d taken the ‘Manhattan Project’ approach and thrown 10x as much money at fusion research 20 years ago we’d most likely have spent most of it on a super-ITER. It might be operational by now and migh…

Probably not. REBCO was discovered in the 80s but is difficult to work with. A fusion energy Manhattan project would make 3-4 reactors in parallel. If it happened in the 2000s then they would have thrown significant effort at HTS technology. That’s one of the most obvious areas to invest in. The whole world would benefit from that.

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

#300

Post by sergeykish »

Stubb wrote: post #87
Florin_Andrei wrote: post #54

Earlier quoted context omitted.

Make an efficient fusion reactor the size of a truck, and the solar system becomes your backyard.

Make an efficient fusion reactor of any size, and you can power Fischer-Tropsch plants to synthesize carbon-neutral hydrocarbon fuel for the existing fossil-fuel infrastructure.

Or convert CO2 to carbon nanotubes
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