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Chinese Tokamak reaches over 100M degrees

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Re: Chinese Tokamak reaches over 100M degrees

#101
post #91
post #53

Earlier quoted context omitted.

ITER will never produce electric energy but they plan to achieve Q=5, ie, output 5 times more energy than put in. The more important work on ITER is work around enabling actual power stations using Q=5 and developing the tech to maintain operating fusion reactors (remote robots, etc.)

At that point can't you just store the output current in supercapacitors for later use anyway? You can even feed it into the machine itself. Supercapacitors easily have better than 20% efficiency for each cycle.

No, ITER doesn't have any planned way to make electricity, the power it outputs will be largely thermal and radiative. Engineers will likely put up a cooling system to measure the thermal output, especially after putting up the various ways to turn the major neutron radiation into heat (which is a fun way to produce energy with rare materials as a byproduct).

DEMO, to my knowledge, will then include an actual electric generator to be hooked up to the fusion core.

Re: Chinese Tokamak reaches over 100M degrees

#102
post #65
post #63

Earlier quoted context omitted.

To a first approximation all matter on earth radiates because all matter is present with some isotopes that will eventually decay. Don't forget that we're sitting on top of a huge ball of molten metal kept hot by ongoing nuclear decay. That process produces all kinds of isotopes that eventually make their way to the surface. The bomb tests did increase background radiation for us; irresponsibly so in my opinion. But…

> I don't see how sunk steel would be any more valuable than steel from freshly mined ore. But I like to be surprised about these things :-) Steel production uses air from the atmosphere. Thus it picks up the increased background radiation while it is refined. It may be possible to scrub the radioactive components from the air to avoid contanimating the steel, but I expect the cost would be prohibitive (at the very l…

Wikipedia agrees with you that the primary source of this steel is from old ships. It is used for Geiger counters, aerospace sensor etc.

https://en.wikipedia.org/wiki/Low-background_steel

Re: Chinese Tokamak reaches over 100M degrees

#103

Earlier quoted context omitted.

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…

A Chernobyl accident can't happen in a western reactor, and it wasn't what happened in Fukushima either, so the lecturers weren't wrong. I don't know the facts of the tsunami whether it was unprecedented or not, but considering the magnitude of the quake I'm guessing it was one of the largest tsunamis to ever hit Japan. This is speculation on my part. They didn't ignore the risk of tsunamis, they had precautions agai…

> A Chernobyl accident can't happen in a western reactor, and it wasn't what happened in Fukushima either, so the lecturers weren't wrong.

He was referring to the core meltdown, not the very specific fault mechanism. I should have made it clear. Otherwise, it would be an uninteresting technicality.

The entire Fukushima incident makes me suspect it's a result of defining an exact fault model and then optimizing to the model. This way, if the fault slightly exceeds the model, the result is not graceful degradation, but catastrophic failure.

Can we put the generators below sea level? sure, the sea wall is high enough, no need to worry about that at all.

> "Build better walls" seems like a trivial problem to solve, don't you think?

Yes, but is it a robust solution?

Re: Chinese Tokamak reaches over 100M degrees

#104
post #70
post #33

Earlier quoted context omitted.

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.

Just like previous predictions that the introduction of fission power plants would result in electricity 'too cheap to meter', I suspect the same will happen for fusion. Even if the fuel is nearly free, you still have to build and maintain the power plant, the grid etc., neither which is cheap. But yes, the first ones to 'crack' the problem will have a head start in the commercial fusion power plant market, but I don…

From what i've read[0] it will remove about a third of the cost (probably less). About a third of energy cost goes on fuel (now almost 0), a third on the grid, and a third on the station (now probably more).

Whilst a 20-30% reduction in energy cost would be great. The really important change is that it is much more scalable and easy to get. You don't need to dig up coal, or drill for oil. All of which can be limited. With a working fusion reactor a country like Singapore can be energy independent, in a way it never could with any other type.

This independence would mean no more need to mess around in areas with these resources (think middle east) or have your countries energy rely on a third party you'd rather not rely on (think Germany and others and their reliance on Russian gas)

[0] A Piece of the Sun: The Quest for Fusion Energy - throughly enjoyed this book.

Re: Chinese Tokamak reaches over 100M degrees

#105
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".

Even with free & unlimited source of heat there will be always a cost for generating each MWh.

Re: Chinese Tokamak reaches over 100M degrees

#106
post #95

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…

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

It's also wrong. Kelvin is not in degrees. It's just 100M Kelvin.

Re: Chinese Tokamak reaches over 100M degrees

#107
post #97

Earlier quoted context omitted.

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...

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.

Re: Chinese Tokamak reaches over 100M degrees

#108
post #94
post #82

Earlier quoted context omitted.

And the war in Iraq $1 trillion :(

$1 trillion is not a lot of money for the US. the Congressional Budget Office estimates that interest spending on US public debt will hit $915 billion in 2028[1]. [1] https://www.wsj.com/articles/u-s-on-a-course-to-spend-more-o...

That doesn't mean 1 trillion isn't a large amount of money. That means the US spends a trillion dollars servicing it's debt. As it so happens, the US will be spending a lot of money servicing debt.

Re: Chinese Tokamak reaches over 100M degrees

#109
post #95

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…

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

In his defense he was commenting on the difference between Kelvin and KeV.

Re: Chinese Tokamak reaches over 100M degrees

#110
post #94
post #82

Earlier quoted context omitted.

And the war in Iraq $1 trillion :(

$1 trillion is not a lot of money for the US. the Congressional Budget Office estimates that interest spending on US public debt will hit $915 billion in 2028[1]. [1] https://www.wsj.com/articles/u-s-on-a-course-to-spend-more-o...

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.
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