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Chinese Tokamak reaches over 100M degrees

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Re: Chinese Tokamak reaches over 100M degrees

#171

Post by jsjohnst »

phkahler wrote: post #147
i_am_proteus wrote: post #3

A tokamak is a kind of fusion reactor, and basically the most prevalent. "100M degrees" (Kelvin) corresponds to 10 KeV (kilo electron volts), which is an important figure to exceed for D-T fusion. D-T fusion which is the kind of fusion the ITER Tokamak (a forthcoming fusion reactor and international megaproject) intends to demonstrate. An older fusion experiment, JET (Joint European Torus) reached these levels, so th…

Didn't old-school CRT televisions "heat" electrons to more than 10KeV?

Considering that multiple particle colliders can accelerate particles over 1 TeV (LHC topping 13 TeV), yes, 10KeV isn’t a very high number taken out of context.

Re: Chinese Tokamak reaches over 100M degrees

#172

Post by stcredzero »

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 :(

Unfortunately, it did change the future, just not in the way its planners thought.

Re: Chinese Tokamak reaches over 100M degrees

#173

Post by simias »

DavidSJ wrote: post #156
simias wrote: post #129

Earlier quoted context omitted.

I remember seeing an infografic a while ago where some very high temperature of like 10 million Kelvins was displayed like "9999728 degrees". I thought it was mildly amusing.

That was probably this: https://www.reddit.com/r/space/comments/2uzgpa/from_absolute...

It must've been, "99,999,999,726 C, the temperature inside a newly formed neutron star"! It's even more preposterous than I remembered. It's not even rounded correctly!

But then again I just noticed that I was off by one in my parent comment so I shouldn't through any stones I suppose.

Re: Chinese Tokamak reaches over 100M degrees

#174

Post by jasonwatkinspdx »

nickdothutton wrote: post #76

Is it just me, or have we converged on 1 reactor design (the tokamak) relatively early on in the process? I appreciate that funds need to be concentrated in order to have an impact, but we have built dozens of this design since the 1950s, yet here we are.

So, the mainline effort is focused on Tokamaks with good reason. A huge population of the smartest physicists around have been debating this topic for several decades. Not to be rude, but armchair opinions here aren't worth much vs that.

Yes we have been building dozens of these. But that's also because it's fundamentally a very difficult project. Do you somehow expect airplanes to go from the Wright flyer to a jumbo jet in less than a dozen steps?

There's also been plenty of research into alternatives. Germany is building a stellarator.

There's also a whole cohort of startups looking at more speculative ideas.

I'm not saying there can't or shouldn't be more research into more alternatives. I am saying it's unreasonable to look at tokamak research as some sort of dead horse we're flogging.

Re: Chinese Tokamak reaches over 100M degrees

#175

Post by docker_up »

kungtotte wrote: post #34
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…

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.

No one is dismissing technology. My point is that humans are terrible at assessing risk.

The Japanese built Fukushima to standards that they felt were acceptable, and they were wrong and now the ocean is being polluted for the next thousands of years with the continuous risk of things getting worse at Fukushima.

In the same manner, they may be building this fusion reactor or LHC with what they feel is acceptable risk, but could they be wrong, with extremely catastrophic results? This is something I don't know but would love to know the answer to.

Re: Chinese Tokamak reaches over 100M degrees

#176

Post by EForEndeavour »

ravar wrote: post #148
muhbags wrote: post #136

Earlier quoted context omitted.

Never. It's either no units (theoretical physics), eV (particle physics) or Kelvin/Celsius for experimental physics.

Technically there is Rankine if you want to do thermo in imperial units.

Technically, Rankine and Fahrenheit are not imperial units.

Re: Chinese Tokamak reaches over 100M degrees

#177

Post by lambdadmitry »

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…

> The DEMO project's goal [3] is to provide commercially available power plants utilizing nuclear fusion

That's not true unfortunately. Yep it's planned to be attached to the grid, but it won't be a production-ready power station. That will be PROTO [1].

Basically the whole schedule slipped more, US pulled out of ITER so they had to scale it down, then it was delayed, so as things stand now DEMO will still be a testbed. Some recent DEMO design notes can be found here [2]. A bit dated, but if anything an optimistic outlook can be found here [3] at page 8. Note that DEMO is though to "resolve" some issues still.

[1]: https://en.wikipedia.org/wiki/PROTO_(fusion_reactor)

[2]: http://www.firefusionpower.org/NAS_EU_DEMO_Federici.pdf

[3]: https://fire.pppl.gov/eu_demo_Stork_FZK%20.pdf

Re: Chinese Tokamak reaches over 100M degrees

#178

Post by yongjik »

Cthulhu_ wrote: post #49
red75prime wrote: post #43

Earlier quoted context omitted.

> 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.

Amount of seawater on Earth: 1.338 billion km^3 (according to Wikipedia). Assuming 1.0 kg/L, this is 1.338 * 10^18 ton.

Seawater is about 0.04% potassium, so this is about 5.35 * 10^14 ton of potassium.

Potassium contains naturally occurring radioactive isotope (40K): the radioactivity of potassium is 31 Bq/g. Hence the natural radioactivity of all potassium in seawater is 1.66 * 10^22 Bq.

For comparison, again according to Wikipedia:

> In May 2012, TEPCO reported that at least 900 PBq had been released "into the atmosphere in March last year [2011] alone"

...which is 9 * 10^17 Bq, or about 1/18,000 of naturally occurring radioactivity in the ocean due to potassium alone.

(We didn't even start on stuff that are commonly considered "radioactive", like all the uranium and thorium lying beneath where you are.)

* Meanwhile we're busy burning fossil fuels, increasing the amount of CO2 in the atmosphere by ~30%.

Re: Chinese Tokamak reaches over 100M degrees

#179

Post by Retric »

abfan1127 wrote: post #162
Retric wrote: post #110

Earlier quoted context omitted.

That’s a very misleading figure as inflation both directly reduces the actual debt payment nessisary, and makes comparisons between spending 2003 – 2011 vs 2028 difficult to compare.

except inflation is directly related to the amount of new debt issued, because thats the only source of M1 money supply. If the US Treasury didn't borrow from the Federal Reserve and instead printed its own currency, this would be different.

The FED can create money from thin air when banks fail. So, debt is not the only source of M1 money supply.

Re: Chinese Tokamak reaches over 100M degrees

#180

Post by sfjlksjfdldas »

phkahler wrote: post #147
i_am_proteus wrote: post #3

A tokamak is a kind of fusion reactor, and basically the most prevalent. "100M degrees" (Kelvin) corresponds to 10 KeV (kilo electron volts), which is an important figure to exceed for D-T fusion. D-T fusion which is the kind of fusion the ITER Tokamak (a forthcoming fusion reactor and international megaproject) intends to demonstrate. An older fusion experiment, JET (Joint European Torus) reached these levels, so th…

Didn't old-school CRT televisions "heat" electrons to more than 10KeV?

Sure, but it costs too much energy to break even (although there are some cute devices that are being researched)
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