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Chinese Tokamak reaches over 100M degrees

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Re: Chinese Tokamak reaches over 100M degrees

#41

Post by miemo »

txcwpalpha wrote: post #15
rococode wrote: post #7

Earlier quoted context omitted.

You seem to know what you're talking about - do you know what the end goal of the work in this field is? Is it working towards nuclear fusion as an energy source?

The specific EAST reactor [1] mentioned in the article is a testbed that will enable new technologies to be used on the ITER project. The ITER project [2] is currently the largest fusion power research project underway (and the largest reactor under construction). ITER's goal is to provide research that enables new technologies to be used on the DEMO project. The DEMO project's goal [3] is to provide commercially ava…

but 2033 is only 15 years away, not 20

Re: Chinese Tokamak reaches over 100M degrees

#42

Post by perlgeek »

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?

https://www.quora.com/Does-nuclear-fusion-produce-waste says "typically less than 30 years for neutron activated fusion chamber materials"

Re: Chinese Tokamak reaches over 100M degrees

#43

Post by red75prime »

docker_up wrote: post #11

Stories like this scare me. With all of the precautions, even things like Fukushima failed and will poison our ocean for millennia. What happens if we have a runaway fusion process through some pathway that was unexpected? With all the talk about the LHC possibly producing mini blackholes or magnetic monopoles that could potentially cause protons to decay spontaneously, I don't have enough nuclear physics background…

> poison our ocean for millennia

On global scale it negligibly increased ever-present background radiation. It's not a good thing, but far from poisoning.

Re: Chinese Tokamak reaches over 100M degrees

#44

Post by baq »

kazagistar wrote: post #29
docker_up wrote: post #11

Stories like this scare me. With all of the precautions, even things like Fukushima failed and will poison our ocean for millennia. What happens if we have a runaway fusion process through some pathway that was unexpected? With all the talk about the LHC possibly producing mini blackholes or magnetic monopoles that could potentially cause protons to decay spontaneously, I don't have enough nuclear physics background…

Uh, worst case it blows up pretty conventionally, lots of heat (but not really, not a lot of actual material is used), and, uh, as far as byproducts... helium? Maybe some lithium or boron o carbon or aomething if things get really wild? Basically it's really really safe as far as byproducts. And yeah, it's a teeny sun, that instantly goes out if you stop feeding it juice, which sounds bad, but it's all the tiny stabl…

All that neutron activated equipment needs to be disposed of, but I guess that’s easier to do than cleaning up a fission reactor.

Re: Chinese Tokamak reaches over 100M degrees

#45

Post by vbezhenar »

thaumasiotes wrote: post #40
NamTaf wrote: post #8

Earlier quoted context omitted.

As I understand, this represents sufficient energy to overcome the Coulomb Barrier [1] which naturally repels atoms apart. To cause fusion, you need to push particles together either hard enough or fast enough that they push through this repulsion and fuse. The repulsion is a product of the electrostatic repulsion of the positive charges of the nuclei (pushing the positive ends of two magnets together, essentially).…

> you need to push particles together either hard enough or fast enough that they push through this repulsion What's the difference between "hard" and "fast"? What does pushing "hard" mean?

I guess hard is something inside the star where matter is compressed by gravity and fast is when you're accelerating matter. In the end it's the same, only you can't use gravity for small reactors to replicate star technology yet, so you must accelerate particles.

SciFi likes to talk about antigravitation. But supergravitation would be cool as well :)

Re: Chinese Tokamak reaches over 100M degrees

#46

Post by Cthulhu_ »

aaaaaaaaaab wrote: post #39
adtac wrote: post #32

Once we achieve sustainable fusion, will it be possible to "share" the energy with everyone else to create more independent fusions? Kinda like keeping the candle burning so as to light more candles because matches are too costly. Now, I don't expect politics to allow sharing of fusion energy to help other countries.

What... no. Igniting fusion is easy. Keeping the plasma confined is the hard part due to its immense heat.

Easy or relatively easy? They still need to pump in enough energy to get it up to a 10 million degree (if not more) temperature.

Re: Chinese Tokamak reaches over 100M degrees

#47

Post by Cthulhu_ »

hoffs wrote: post #33
adtac wrote: post #32

Once we achieve sustainable fusion, will it be possible to "share" the energy with everyone else to create more independent fusions? Kinda like keeping the candle burning so as to light more candles because matches are too costly. Now, I don't expect politics to allow sharing of fusion energy to help other countries.

Isn't fusion reactor basically infinite energy, I mean sure it makes total sense to no share it with other because you can sell your free energy for cash, but considering that a lot of global scientists work on it and most of the findings are published, don't think that such strategy would last long.

> Isn't fusion reactor basically infinite energy

It's probably not that easy; the reactors are extremely complicated and expensive to build, and I'm sure operating them isn't cheap either.

And the one thing I haven't heard much about yet is the yield - how much energy can it generate vs how much will it cost to run.

I don't think it'll be economically viable. I'll be happy to be proven wrong though.

Re: Chinese Tokamak reaches over 100M degrees

#48

Post by Cthulhu_ »

baq wrote: post #44
kazagistar wrote: post #29

Earlier quoted context omitted.

Uh, worst case it blows up pretty conventionally, lots of heat (but not really, not a lot of actual material is used), and, uh, as far as byproducts... helium? Maybe some lithium or boron o carbon or aomething if things get really wild? Basically it's really really safe as far as byproducts. And yeah, it's a teeny sun, that instantly goes out if you stop feeding it juice, which sounds bad, but it's all the tiny stabl…

All that neutron activated equipment needs to be disposed of, but I guess that’s easier to do than cleaning up a fission reactor.

I read in another thread that the radiation in that dissipates in about 30 years, vastly preferable to the tens of thousands of years of nuclear fission waste. I don't know how strong the radiation is either, whether it's more or less dangerous than fission waste.

Re: Chinese Tokamak reaches over 100M degrees

#49

Post by Cthulhu_ »

red75prime wrote: post #43
docker_up wrote: post #11

Stories like this scare me. With all of the precautions, even things like Fukushima failed and will poison our ocean for millennia. What happens if we have a runaway fusion process through some pathway that was unexpected? With all the talk about the LHC possibly producing mini blackholes or magnetic monopoles that could potentially cause protons to decay spontaneously, I don't have enough nuclear physics background…

> poison our ocean for millennia On global scale it negligibly increased ever-present background radiation. It's not a good thing, but far from poisoning.

Wasn't said ever-present background radiation only a thing after the nuclear bomb tests? I read a while ago that steel from old ships that sunk deep is highly valuable because it's not irradiated yet.

Re: Chinese Tokamak reaches over 100M degrees

#50

Post by semi-extrinsic »

thaumasiotes wrote: post #40
NamTaf wrote: post #8

Earlier quoted context omitted.

As I understand, this represents sufficient energy to overcome the Coulomb Barrier [1] which naturally repels atoms apart. To cause fusion, you need to push particles together either hard enough or fast enough that they push through this repulsion and fuse. The repulsion is a product of the electrostatic repulsion of the positive charges of the nuclei (pushing the positive ends of two magnets together, essentially).…

> you need to push particles together either hard enough or fast enough that they push through this repulsion What's the difference between "hard" and "fast"? What does pushing "hard" mean?

They may be trying to differentiate between high temperature as "fast", like in this case, and high pressure as "hard". Though both can lead to a particle kinetic energy above the Coloumb barrier, in the former case the time between collisions will be lower (AFAICT), which may be important. I'm not a plasma guy though.
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