/sci/ - Science & Math

[Anonymous No.5843632]

What is the current obstacle preventing us from achieving nuclear fusion?

[Fauxstyle No.5843636]

>>5843632
Muh Second LTD and lack of followthrough and ballseyness, lots of guys have been close over the years :p

[Anonymous No.5843640]

Muh Thorium.

[Anonymous No.5843646]

>>5843632
an artificial intelligence that's superior to all human brains combined.

[Anonymous No.5843654]

>>5843636
>>5843640
>>5843646

I guess this is why I always hear "don't go to /sci/ with a science question.' ...

[Anonymous No.5843657]

>>5843632
Designing a reactor which can provide sufficient force to overcome the electromagnetic repulsion of the particles and trigger fusion in a way which is sustainable and takes less energy than the fusion reaction puts out.

[Anonymous No.5843656]

>>5843632
>>5843654
-lack of funding
-takes ages to build a reactor
-not all research on the subject is complete

/thread

[Anonymous No.5843659]

Juice

[Anonymous No.5843670]

>>5843654
>expecting actual scientific discussion on 4chan
>during american prime-time

[Anonymous No.5843674]

Fucking plasma instabilities. Theres a fuckton of them.
It always makes recent Tokamak fusion reactions switch-off after ~30 seconds.

Pic related, the H-Mode instability, a major obstacle only found and understood at the end of the 1980's.

That's why it seems always to be "Only 40 more years until fusion"...

[Anonymous No.5843677]

>>5843632
Ultimately, lack of funding/investment due to the stigma of the word "nuclear" to the uneducated and ignorant (most of US constituency).

[Anonymous No.5843678]

>>5843656
No, there is plenty of pork going to fusion research. More than any other nuclear research, sadly.

Sustainable fusion outside the core of a star is just really really really really fucking hard. Dem neutrons embrittle and contaminate everything they touch. Dat plasma is so hard to contain.

I'm interested to see whether the General Fusion prototype will work though. Giant pistons for both compressing and extracting energy! very gar.

[Anonymous No.5843680]

Fusion was achieved 80 years ago.

[Nuka-Cola: Neutron Nectarine No.5843834]

turbulence
whether it's beam smoothing in IFC or chaotic plasma currents in MFC, it's always fucking turbulence

seriously, fuck it

[Nuka-Cola: Neutron Nectarine No.5843837]

>>5843834
MCF*

[Anonymous No.5843892]

>>5843632
mass.

it'll work fine if we get enough hydrogen with the right mass. Maybe we can take it from the sun?

[Anonymous No.5843896]

>>5843678
so they are making a hydrogen diesel engine and calling it "fusion"?

kay

[Anonymous No.5843907]

>>5843892

I have a great design for a gravitationally contained fusion reactor.

[Anonymous No.5843911]

>>5843896
Pneumatic pistons. You'll see bro, these things will be rolling off the assembly lines.

[Anonymous No.5843921]

>>5843632
goddamn jews

[Nuka-Cola: Neutron Nectarine No.5844246]

>>5843896
he's talking about magnetized target fusion, which looks pretty promising.
however i'm willing to bet they'll lose a lot of efficiency to imperfect implosions caused by...you guessed it....turbulence

[Anonymous No.5844249]

>>5843632
We can achieve nuclear fusion already. It's so easy you can do it with a machine that DIYers build in their garages, and fusion reactors that ALMOST reach breakeven are used frequently as easy neutron sources.


What we can't do yet is create a nuclear fusion reactor that produces more power than it takes to keep the fusion reaction going.
The basic issue is that you have to figure out how to contain a plasma at incredibly high temperatures and pressures, and maintain it at those temperatures and pressures. This is hard, and we're not sure how to do it, and current approaches have all fallen just a little bit short.

[Anonymous No.5844251]

>>5843834
What about inertial electrostatic confinement? You don't have to deal with slinging your plasma around like you do in tokamaks or the complicated issues of injecting and crushing magnetic capsules like in MFC. All the plasma's just attracted to the center. Would that have the same turbulence issues?

[Nuka-Cola: Neutron Nectarine No.5844256]

>>5844251
>inertial electrostatic confinement
if you mean fusor designs and their ilk, i believe the problem there is fundamental physical limits preventing you from hitting breakeven, from summed energy losses.
i think there's a few papers floating around basically stating "the fusor concept will never work, no matter how much you dress it up"

[Anonymous No.5844260]

>>5844256
I've heard of such papers, but I've been Googling for a while and I can never find them- I may be using the wrong search terms, or Google's search bubbling may have convinced itself that I don't really want to find them. Could you shoot me a link? I'm genuinely interested.

[Anonymous No.5844267]

>>5844260
Hi,

I believe the paper you might be referring to is the paper by Dr. Todd Rider who was an avid member of the fusor.net forums.

His paper entitled "A general critique of inertial‐electrostatic confinement fusion systems " is a great reference point for the detailed problems with IEC fusion reactors.

http://pop.aip.org/resource/1/phpaen/v2/i6/p1853_s1?isAuthorized=no

[Anonymous No.5844268]

I think someone once likened using magnetic fields to contain plasma with using fishing line to contain jello.

[Anonymous No.5844273]

>>5844267
Excellent! Thank you. I hope that it's wrong, but I'll try and keep an open mind. I'm not at all confident that practical breakeven fusion is possible with any known method besides gravitational confinement, but I was really hoping that Polywell-style IEC could work.

[Anonymous No.5844277]

>>5844273
Apologies, here is a link to free version.

http://fsl.ne.uiuc.edu/IEC/Rider,%20Phys.ofPlasmas1995.pdf

[Nuka-Cola: Neutron Nectarine No.5844285]

>>5844268
i'm not entirely sure that's a good analogy.
maybe fishing line to contain a large bundle of springs? eventually one of them is going to SPROING out and ruin everything

[Anonymous No.5844286]

Could fusion reactors blow up chernobyl style?
>tfw irradiated

[Anonymous No.5844293]

>>5844246
THAT IS SO FUTURISTIC LOOKING!

[Anonymous No.5844299]

>>5844286
No, no they could not. As soon as you lose containment and the reactor "blows up", the fusion reaction abruptly ceases to work because containment's the only thing keeping it going.

Also, Chernobyl didn't "blow up." It just vented a whole load of radioactive shit. Less of a "BOOM" and more of a deadly "pffffffft." The thing with fusion is that the fuel is basically just hydrogen- it's not inherently radioactive. (Unless you're doing D-T fusion, in which case it's not VERY radioactive. In any case, hydrogen's lighter than air, so all the radioactive shit goes up into the sky and you never see it again instead of going down as fallout.)

[Nuka-Cola: Neutron Nectarine No.5844320]

>>5844293
it's also badass as fuck
>it's literally equally spaced steam-powered pistons that bang on a central sphere about ten times a second, which causes a lead/lithium implosion in the center which initiates fusion

the sound of this thing in operation must be absolutely deafening. and it's almost like a fusion internal combustion engine

[Anonymous No.5844328]

>>5843896
Huh, that's not actually a bad idea. What if there was a way to create an internal combustion engine running off fusion power? Basically miniaturized, ultra-efficient hydrogen bomb (which is, of course, the only currently feasible way achieve brake-even fusion) would be immersed in water and detonated inside a very large cylinder. The water would quickly vaporize and expand, delivering energy to the piston.

It would make this engine look like a moped engine:
http://www.youtube.com/watch?v=2MLkbHkxk-g
I wonder what the torque figure would be like...

[Anonymous No.5844331]

>>5844320
>lead-lithium

....This doesn't exactly scream "energetically favorable" to me.

[Anonymous No.5844338]

>>5844328
You would still need fissionable material for that.

[Anonymous No.5844343]

>>5844338
Yes, but a relatively small amount. The fusion yield would be considerably higher than the fission component. A pure fusion device would be preferable, but with current technology we can create fusion bombs that are extremely efficient and produce very little fallout.

[Anonymous No.5844349]

>>5843632
>What is the current obstacle preventing us from achieving nuclear fusion?
The laws of physics.

[Anonymous No.5844379]

>>5843632
With the modern magnetic containment, you're talking about a plasma with a stupidly high temperature mere meters from superconductors supercooled to less than a degree kelvin. The slightest "mistake", and the plasma will heat those magnets, and your entire setup is fried. The magnets are also damned expensive in terms of electricity power, which means harvesting enough energy from the fusion to power the magnets is difficult and has not yet been done.

There's also the problem of neutron flux. If you run a reactor like this for any appreciable period of time, the high energy neutrons are going to destroy your reactors in a matter of days or hours.

Other approaches aren't much more promising.

[Nuka-Cola: Neutron Nectarine No.5844385]

>>5844331
the lead is mostly a neutron absorber, the lithium is just breed stock to get more tritium

i'm pretty sure you get like 90% neutron absorption per fusion event, possibly even more. Mind you it's all lost as heat in the lead, but the lead is the working fluid anyway so it's a pretty sweet system, as your radiation shielding is also your absorption medium. potentially great efficiencies right off the bat

[Nuka-Cola: Neutron Nectarine No.5844388]

>>5844328
>>5844343
you might think that, but this does not scale down well, mostly because with a smaller diameter of sphere your neutron absorption drops off dramatically, until eventually you only "catch" a small fraction of them and the rest just radiate into the driver's compartment. shit efficiency AND very deadly.

[Anonymous No.5844395]

>>5844379
>neutron flux

Unless you can somehow get your reactor efficient enough to extract an energy surplus from hydrogen-boron fusion, which is neutron-free, and has almost entirely neutron-free side reactions.

It's just that nobody's trying to do H-B fusion right now, because while it's still energetically favorable, it's less so than D-T, and we can't even get D-T to shit out an energy surplus.

[Nuka-Cola: Neutron Nectarine No.5844398]

>>5844395
must admit, i've heard of boron-boron fusion using the plasma pinch concept but i've never heard of hydrogen boron

[Anonymous No.5844411]

>>5844398
The p-11B reaction is used for most studies of aneutronic fusion, because it's the easiest. It's still way harder than D-T or D-D, though, and we haven't even gotten those to work past breakeven yet.

Aneutronic fusion can happen, but we can't even get fusion that spews neutrons all over the place to be used as a practical power source, and in fact right now the only use of fusion reactors is as a neutron source. Aneutronic fusion will be pursued once we can get power-generating fusion working at all.

[Nuka-Cola: Neutron Nectarine No.5844422]

>>5844411
i see
and this is why i like the sound of MTF, because really sloppy neutron flux is actually a good thing and generates (some) of the heat energy

[Anonymous No.5844457]

>>5844379
>Other approaches aren't much more promising.
The tokamak crowd have to protect their funding. Right now they've got a pretty good scam going on with governments handing them trillions of dollars to not do anything before 2050 because they convinced everyone it's the only way that will work. If someone else comes along and shows they can build something by 2020 the whole house of cards comes crashing down, and we can't have that.

[Anonymous No.5844471]

>>5844457
That sounds an awful lot like a scientific conspiracy.

[Anonymous No.5844480]

>>5844457
I seriously doubt anyone in this thread has the required knowledge of fusion systems to be able to understand whether or not a tokamak reactor is a plausible power generator.
If you did you would stop calling it a big conspiracy, considering it is at the forefront of research, and the whole point of research is to theorize and then test to see if it is physically possible. You don't know the future, stop pretending you are smarter than the leading scientists.

[Anonymous No.5844486]

we just need bigger lasers.

[notfaggot No.5844497]

>>5844246
steampunk fusion

[Anonymous No.5844509]

>>5844299
>Less of a "BOOM" and more of a deadly "pffffffft."
>silent but deadly
Cleaning soda off my keyboard again.

[Anonymous No.5844516]

>>5844509
That fucking game. I suck so bad at it.

[Anonymous No.5844520]

>>5844379
>>5844388
I'm reminded of the fusion-powered forcefield belts used by Foundation personnel in the eponymous series.

Imagine them being based on this principle.
>The all new Vibrating Massaging Shieldbelt!
>Also, no more worries of accidental parenthood!

[Anonymous No.5844526]

>>5844516
Well, don't play against Sophons. As you can see, their ships are rape incarnate.

[Nuka-Cola: Neutron Nectarine No.5844537]

>>5844520
>Also, no more worries of accidental parenthood!
more like
>new, less humane form of suicide! die in mere hours of unspeakable agony as you melt from the inside!

[Anonymous No.5844543]

>>5844388
>>5844520
I think you misunderstood my idea, it was for something like a huge municipal power station, not a road vehicle. Obviously pistons powered by thermonuclear detonations don't scale down well. The cylinders would have to be enormous and slow moving.

[Anonymous No.5844546]

>>5844537
Well, in the same story where they went more into the shieldbelts, there was also something about a battlecruiser with a hull that could withstand certain kinds of radiation without becoming radioactive itself(IIRC), so I'm imagining only a little leakage of radiation.

>>5844543
Now you're thinking with nuclear steampunk!

[Anonymous No.5845421]

>>5844471
Not a conspiracy as such, but they have a strong financial incentive to spread FUD about alternative approaches.
>no one ever got fired for buying IBM

[Anonymous No.5845429]

We can do nuclear fusion. We have bombs for that.