North Korea has already proven the existence of Unicorns so at this rate they'll have mastered time by next week by powering a time machine with viable fusion technology from the future.008Zulu said:
It happens because it is short term reaction. Reactor capable of continuous operation would compensate for electricity used to start the reaction and maintain it (at least that's the idea)Neferius said:
True, but H is the most abundant chemical on Earth, in our solar system and arguably in our galaxy.
Just one question.cikame said:
No scientific background beyond my grade 12 chemistry course - just really enjoy and appreciate the amazing things science accomplished. Didn't stop me from diving into the Science and Tech podcast either.Lightknight said:
JET was hitting temperatures much higher than this back in the '90s, and could sustain it for up to 30 seconds. 102 seconds might be a record for time, but it's not that much higher than previously achieved and is much less impressive in pretty much every other way so going on about how hot it is is extremely misleading.Fanghawk said:
It's not. EAST is part of the ITER collaboration and is one of the reactors, along with JET and others, used for testing technologies and theory for ITER. This isn't some wild claim from China trying to one-up everyone else, it's an important step for a major international project.Renegade-pizza said:
If you're going to accuse people of lying, you should perhaps try not to be so hilariously wrong in your own claims. JET currently holds the record for gain factor of 0.7 - that is, the power generated was 70% of that used in running the machine. And this isn't like NIF's figure that neglected a lot of the losses, that's actual power use. Others have even claimed to have Q > 1, meaning they produced more power than was used, although these were based on extrapolations and aren't generally considered good enough to claim the record.Neferius said:
Not in any meaningful sense. There's so much hydrogen available just on Earth that we could power civilisation for millions of years at absolute minimum, and probably much longer, before coming close to running out. And given that it's by far the most abundant element in the universe, it's not like we'd struggle to find other sources if we needed.
Water is HO[sub]2[/sub] now? I guess we can add that to the list of interesting things that can be learned from your post.
Thorium reactors don't require the use of plutonium, they simply require a neutron source. Most thorium reactors have used uranium, not plutonium, for this, although the ideal is an accelerator driven reactor that doesn't require seed fuel at all.
Is this actually true? There's certainly a lot of hydrogen on Earth, but if I recall correctly the type of hydrogen used for fusion is heavy hydrogen, which IIRC accounts for less than a tenth of one percent of total hydrogen. Add to this the fact that effectively all the hydrogen on the planet is bound up in other compounds (such as water) which requires even more energy to isolate, and things don't seem to be looking too good.Kahani said:
Well this seems to coincide with what I imagine would happen after a catastrophic tokamak reactor failure.Kalki said:
It's actually closer to a hundredth of one percent. But the thing is, oceans are really, really big. See Wiki here [https://en.wikipedia.org/wiki/Fusion_power#Advantages], although one of the citations seems to be broken which can be found here [http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.22.1406&rep=rep1&type=pdf]. In fact, this paper says that there are billions of years worth, not just millions, with even more once you start looking at other fuels like lithium. Of all the problems fusion power has, abundance of fuel is not one of them.The_Great_Galendo said:
While this does need to be taken into account, it's so small as to be essentially negligible. This is due to the vast difference in energies of nuclear reactions compared to chemical ones. The energy required to break both bonds in a water molecule is 9.95 eV. The energy released in a D-D fusion reaction is 12.5 MeV - over 1,000,000 times more. It's estimated that a practical power plant would need a Q value of around 10 (ie. you need to get out 10 times as much energy as is used to run the power plant). Even assuming those estimates don't already take things like fuel production into account, electrolysis of water would only change that to 10.00001. Basically, if we can get to the point where fusion is a practical fuel source, the energy requirements to produce the fuel are not going to be a significant problem.
It's not technically wrong, but it misses by far the most important point - the amount of tritium that is actually present. See here on the ITER website - this claims only a few grams are in use at any time, although I've previously read it would be more like half a gram of combined deuterium-tritium fuel. Yes, tritium is a pretty nasty one to get in your body, but even a catastrophic explosive failure would release such a tiny amount into the environment that it would be basically irrelevant; unless one person managed to inhale the lot it would barely even be measurable. And speaking of explosive failure, see [url="http://www.iter.org/faq#Is_the_energy_stored_in_a_100-million-degree_plasma_dangerously_large" [http://www.iter.org/faq#What_procedures_are_foreseen_to_avoid_any_loss_of_tritium_mostly_during_the_first_tests_incomplete_fusion_"[/url]. Because there's such a small amount of material involved, the actual energy isn't all that high and wouldn't be enough to significantly damage the reactor beyond superficial surface damage. A Chernobyl-type scenario where you spray radioactive matter across the landscape simply isn't possible for a fusion reactor. That's why fusion, and also thorium fission, are so good from a safety point of view - with modern fission plants there are all kinds of safety systems to prevent problems, but with fusion and thorium many of the problems are simply physically impossible even in an absolute worst case scenario.Kalki said:
ITER is going to (assuming it works) produce 500MW output power. That's more than many existing power plants. This is not a small-scale test lab, it's a full scale demonstration model. The risk of catastrophic failure you are so concerned about simply does not exist, and you should probably learn at least a little bit about a topic before arguing about it, since you clearly have very little knowledge of what ITER actually is or how fusion works.Kalki said:
We're not going to suddenly start building plants producing hundreds of gigawatts, fusion plants will be the same size as existing ones - up to a few times larger than ITER at most.Kalki said:
10 minutes per pulse, with the later part of the program specifically dedicated to increasingly frequent pulses as would be required in an operating power plant. As noted before, tokamaks are always pulsed systems, and that will still be the case for power plants. Exactly what the optimal pulse length and frequency is is, of course, still under investigation, but it will be a similar magnitude to that of ITER because, once again, that is the entire point of ITER.
Yes it will. That's precisely one of the things ITER is intended to test.
They wouldn't be particularly important differences if they actually existed, but once again you've demonstrated a total lack of knowledge of what ITER actually is by being categorically wrong about every single claim you've made.
You mean the original version in which I said exactly the same as in the current version, but realised I was repeating myself so tidied it up into just one paragraph? Yeah, because obviously that means I'm only acting as if I know what I'm talking about. On the other hand, we have someone who didn't know ITER was a full scale 500MW reactor, didn't know only a couple of grams of fuel at most would be used, didn't know there is only enough plasma to do superficial damage to the containment vessel, didn't know ITER will breed tritium, doesn't understand what a pulsed system is, and in fact has so far failed to get a single statement even close to correct. Someone is certainly acting here, and I'm pretty sure it's the one who has repeatedly demonstrated they don't have the slightest clue what they're talking about. I can see why such a person might be concerned they would appear:
Although I'm less sure why a person with such a comprehensive lack of knowledge and understanding would claim:Kalki said:
Kalki said:
