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Chinese Tokamak reaches over 100M degrees

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Re: Chinese Tokamak reaches over 100M degrees

#111

Post by whatshisface »

arez wrote: post #85
NamTaf wrote: post #24

Earlier quoted context omitted.

It is incredibly high. We hold it in not by any material, but by magnetic fields. Plasma has the handy feature of being magnetic. The Tokamak[1] design used in ITER and this example uses a whole heap of magnets to hold this plasma in a doughnut-shaped area. [1]: https://en.wikipedia.org/wiki/Tokamak

Doesn't it take a lot of energy to have such a big magnetic field?

Fundamentally it doesn't have to, because like a weight resting on the top of a ladder magnetic fields store energy and do not dissipate it. In practice it does because our ways of producing and maintaining strong magnetic fields require a lot of upkeep. This, like most things in fusion, is an example of where the realities of present day engineering are far cruler than the laws of physics.

Re: Chinese Tokamak reaches over 100M degrees

#112

Post by sergiosgc »

qwerty456127 wrote: post #83
mrpdaemon wrote: post #10

The main challenge in working with these high temperature plasmas is confinement. In order to achieve nuclear fusion matter needs to be heated to immense temperature, so that the kinetic energy of nuclei colliding can overcome the electrostatic force of the protons pushing each other away and "fuse" into larger nuclei (held together by the "strong force"), converting a fraction of the reaction mass into a relatively…

> If the plasma "escapes" the confinement and contacts anything (ie. the walls of the Tokamak) it rapidly cools down to temperatures below where fusion can happen. Sounds relieving. I used to think that «if the plasma "escapes" the confinement and contacts anything (ie. the walls of the Tokamak) it rapidly…» disintegrates everything around or, when the power is huge enough, causes an apocalypse…

At those temperatures, it will disintegrate whatever it touches. It's just that, unlike fission, fusion is unstable[1] so it quickly fizzles out, and damage will be local.

[1] Unstable in the sense that it is hard to maintain fusion conditions, not in the Hollywood sense that it blows up if you look at it sideways.

Re: Chinese Tokamak reaches over 100M degrees

#113

Post by jniedrauer »

qwerty456127 wrote: post #83
mrpdaemon wrote: post #10

The main challenge in working with these high temperature plasmas is confinement. In order to achieve nuclear fusion matter needs to be heated to immense temperature, so that the kinetic energy of nuclei colliding can overcome the electrostatic force of the protons pushing each other away and "fuse" into larger nuclei (held together by the "strong force"), converting a fraction of the reaction mass into a relatively…

> If the plasma "escapes" the confinement and contacts anything (ie. the walls of the Tokamak) it rapidly cools down to temperatures below where fusion can happen. Sounds relieving. I used to think that «if the plasma "escapes" the confinement and contacts anything (ie. the walls of the Tokamak) it rapidly…» disintegrates everything around or, when the power is huge enough, causes an apocalypse…

One of the beautiful things about nuclear fusion reactors is that they are inherently unstable at STP. In the event of a catastrophic failure, they will simply stop working (potentially after some large bangs).

Nuclear fission reactions can continue on their own for quite a while. This is one of the reasons they can be so dangerous.

Re: Chinese Tokamak reaches over 100M degrees

#114

Post by fyfy18 »

zaarn wrote: post #107
proto-n wrote: post #97

Earlier quoted context omitted.

Is money more limiting than time though? Nine woman and a child analogy comes to mind.

Fusion is notoriously underfunded. More money means you can buy better gear, hire more workers, complete projects faster and run multiple parallel sites to complete various goals at the same time. Of course there is some point where adding more funding will not advance the speed as much anymore but I doubt were even close to that point at the moment.

Why is it so underfunded? The first country to build one will be taking a big step to reducing their dependence on other countries for energy. I can understand big oil exporters not wanting to push it too much (although it's unlikely to come into fruition for the current generation of politians), but for others isn't it a no brainer?

Re: Chinese Tokamak reaches over 100M degrees

#115

Post by Aardwolf »

agoldis wrote: post #5

Okay, did some search: - When two hydrogen nuclei combine, they produce an enormous amount of energy. That process is known as nuclear fusion. - Light nuclei have to be heated to extremely high temperature, it is challenging to create a controlled, safe fusion reactor that offers more energy than it consumes. Once we have such we’d have a near-limitless source of clean energy. - Nuclear fusion does produce radioactiv…

> Once we have such we’d have a near-limitless source of clean energy.

In some dystopian future, an AI figures out this is a most efficient use of matter and the entire Earth gets used as fuel for fusion reactions

Re: Chinese Tokamak reaches over 100M degrees

#116

Post by Dylan16807 »

qwerty456127 wrote: post #83
mrpdaemon wrote: post #10

The main challenge in working with these high temperature plasmas is confinement. In order to achieve nuclear fusion matter needs to be heated to immense temperature, so that the kinetic energy of nuclei colliding can overcome the electrostatic force of the protons pushing each other away and "fuse" into larger nuclei (held together by the "strong force"), converting a fraction of the reaction mass into a relatively…

> If the plasma "escapes" the confinement and contacts anything (ie. the walls of the Tokamak) it rapidly cools down to temperatures below where fusion can happen. Sounds relieving. I used to think that «if the plasma "escapes" the confinement and contacts anything (ie. the walls of the Tokamak) it rapidly…» disintegrates everything around or, when the power is huge enough, causes an apocalypse…

That description of destruction is entirely correct, it's just that the amount involved is tiny. Just like a big enough firecracker could destroy anything, but the ones we make just go pop.

Re: Chinese Tokamak reaches over 100M degrees

#117

Post by jdironman »

marcosdumay wrote: post #98
maaaats wrote: post #95

Earlier quoted context omitted.

> "100M degrees" (Kelvin) Off topic, but this distinction made me laugh. Like the difference between Kelvin and Celsius would throw everything off.

Well, there is almost certainly somebody that read the number and thought about Fahrenheit.

I'm that somebody.

Re: Chinese Tokamak reaches over 100M degrees

#118

Post by Dylan16807 »

yreg wrote: post #96
dmos62 wrote: post #90

Can someone comment on what kind of economic effect that working fusion reactor technology would have? I hear sometimes contradictory hear-say on the lines of "unlimited energy", "reactor would have to be fed constantly".

One liter of ordinary seawater would still produce as much energy in a fusion reaction as 500 liters of fossil fuels in a chemical reaction. — random guy on Quora https://www.quora.com/Is-there-a-limited-amount-of-fuel-for-...

Oh, that sentence is a bit misleading, that's talking about using purely the 0.015% of deuterium in the water.

Re: Chinese Tokamak reaches over 100M degrees

#119

Post by zaarn »

fyfy18 wrote: post #114
zaarn wrote: post #107

Earlier quoted context omitted.

Fusion is notoriously underfunded. More money means you can buy better gear, hire more workers, complete projects faster and run multiple parallel sites to complete various goals at the same time. Of course there is some point where adding more funding will not advance the speed as much anymore but I doubt were even close to that point at the moment.

Why is it so underfunded? The first country to build one will be taking a big step to reducing their dependence on other countries for energy. I can understand big oil exporters not wanting to push it too much (although it's unlikely to come into fruition for the current generation of politians), but for others isn't it a no brainer?

Historically, Fusion has been bad at predicting when it's going to be ready for prime time, that plus very early fusion experiments turned out to be a lot of duds. Just think of the Cold Fusion hype (on a side note; cold fusion does work, µCF replaces electrons with muons in the hydrogen atom which reduces the radius of the atomic nucleus such that fusion becomes possible at room temperature and far below but generating the necessary muons is a fools game) and the various other nuclear fusion failures.

Fission on the other hand could report a lot of results and success and, at the time, seemed to be infallibly safe.

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