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Chinese Tokamak reaches over 100M degrees

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Re: Chinese Tokamak reaches over 100M degrees

#81

Post by martinw111 »

Someone wrote: post #51
miemo wrote: post #41

Earlier quoted context omitted.

but 2033 is only 15 years away, not 20

I think calling 2033 highly unlikely would be an understatement. https://en.wikipedia.org/wiki/ITER : ”Initial plasma experiments are scheduled to begin in 2025, with full deuterium–tritium fusion experiments starting in 2035.” So, according to Wikipedia, DEMO will build on ITER’s results, but will produce energy before ITER’s first real fusion experiment starts.

If global warming will be more significant then is predicted now I believe they will suddenly invest 100x more into this technology. This and nuclear plants are only reasonable way how to have available energy for some 'CO2 removal' projects...

Re: Chinese Tokamak reaches over 100M degrees

#82

Post by namdnay »

donkeyd wrote: post #74
elorant wrote: post #66

Earlier quoted context omitted.

Initial budget was €5bn. Current budget is four times that and with completion nowhere near estimates of the final cost are as high as $60bn. Go figure. If by "we" you mean US's share, that's 9% of total costs. China, India, Japan, Russia, South Korea, and the US are paying 9% each and EU is paying 46%.

With 'we' I meant every country that's involved, not just my own country. $60bn is actually surprisingly little for research that could change the future of energy production and possibly society as we know it. To put it into context, the Apollo program cost $200bn in today's money and a high speed train between LA and SF is projected to cost $100bn.

And the war in Iraq $1 trillion :(

Re: Chinese Tokamak reaches over 100M degrees

#83

Post by qwerty456127 »

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…

Re: Chinese Tokamak reaches over 100M degrees

#84

Post by shawabawa3 »

oldgradstudent wrote: post #52
kungtotte wrote: post #34

Earlier quoted context omitted.

The earthquake was the most powerful to ever hit Japan and the fourth most powerful in the world since modern record keeping began, and the investigation into the disaster showed that the safety precautions weren't adequate in the first place. You can't dismiss the technology based on that incident. Just like we don't ban cars because a lot of people don't operate them properly.

When I was in high school we visited a small 5MW nuclear reactor. It was a few years after Chernobyl and we got a very long lecture about how this was all the fault of the terrible Soviet design and that it could never happen in a western-designed nuclear reactor. As far as I remember from the news at the time, the tsunami was terrible, but not unprecedented. If this obvious risk was ignored, what other risks are bei…

It's also important to note that literally one person has died as a direct result of the reactor failing in Fukoshima. Around 1600 died in the evacuation process, mainly elderly people.

The earthquake itself killed over 15000 people.

Imo it's a massively overblown disaster. Yes, it's bad, especially the environmental effects, but it's absolutely nothing compared to the earthquake and tsunami itself.

Re: Chinese Tokamak reaches over 100M degrees

#85

Post by arez »

NamTaf wrote: post #24
argc wrote: post #14

100M seems insanely high, beyond what anything man made would be able to contain. Is it extremely short lived? Or over a very small area? Very interesting.

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?

Re: Chinese Tokamak reaches over 100M degrees

#86

Post by saagarjha »

fapjacks wrote: post #72
NamTaf wrote: post #31

Earlier quoted context omitted.

Expanding on this, this 10KeV temperature is the average of all particles, and there's a distribution around this average. Some will be higher, and thus more capable of colliding with high energy. In addition to that, whether two nuclei fuse is also dependent on how squarely they collide. A glancing blow intuitively allows both nuclei to push each other away a lot easier than if they experience a head-on collision. A…

How does one control the chain reaction of the fusion process? I understand fission reactors using control rods to absorb some of the neutrons to prevent those neutrons from hitting other fissile particles, but this seems like a harder problem. Those particles fusing at a "low" temperature in the distribution of equilibrium cause additional fusion reactions at higher temperature thresholds in other particles because…

Basically, yeah. It’s very hard to sustain a reaction like this, so to stop it all you need to do is stop trying your hardest to keep it stable.

Re: Chinese Tokamak reaches over 100M degrees

#87

Post by donkeyd »

namdnay wrote: post #82
donkeyd wrote: post #74

Earlier quoted context omitted.

With 'we' I meant every country that's involved, not just my own country. $60bn is actually surprisingly little for research that could change the future of energy production and possibly society as we know it. To put it into context, the Apollo program cost $200bn in today's money and a high speed train between LA and SF is projected to cost $100bn.

And the war in Iraq $1 trillion :(

Yup. I purposefully didn't mention it, because it can lead to distracting political discussions, unfortunately.

Re: Chinese Tokamak reaches over 100M degrees

#88

Post by nielsole »

afraca wrote: post #37
i_am_proteus wrote: post #27

Earlier quoted context omitted.

I will add: - While the products of the fusion reaction are short-lived, operating a fusion reactor will active materials in the reactor and create some longer-lived radioisotopes. - Unlike a fission reactor, which is loaded with months to years worth of fuel, a fusion reactor would have fuel constantly injected. So operator action to stop injecting fuel would stop the nuclear reaction.

Can either you or your parent poster say what "short lived" and "longer-lived" would be roughly?

I recall from a talk a couple of years back ( so not sure I got it correctly) that after 50-100 years you can basically walk into the fusion reactor without having to worry about radiation.

Re: Chinese Tokamak reaches over 100M degrees

#89

Post by saagarjha »

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?

It does, which is why most fusion reactions currently produce a net negative amount of energy.
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