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China to Build World's First "Artificial Sun"
cletuii writes to tell us the People's Daily Online is reporting that China is planning on building the world's first "artificial sun" device. From the article: "The project, dubbed EAST (experimental advanced superconducting Tokamak), is being undertaken by the Hefei-based Institute of Plasma Physics under the Chinese Academy of Sciences. It will require a total investment of nearly 300 million yuan (37 million U.S. dollars), only one fifteenth to one twentieth the cost of similar devices being developed in the other parts of the world."
Wikipedia has some info about Tokamak reactors, and fusion power in general. I still don't get it ;)
See also the Joint European Torus, the largest nuclear fusion reactor yet built, and ITER, the international attempt to build a much bigger one.
They are building an experimental fusion reactor, a Tokomak. While I suppose you could call it an artifical sun, I think a better choice of words would be tokomak or fusion reactor.
On another note, this is not a one of a kind device. Europe has one called JET, and is planning on making another, ITER.
If you are about to mod me down, keep in mind that this post was most likely sarcastic.
No. The produced Helium in the Tritium-Deuterium reaction slows it down until it stops. In fact one of the problems of fusion with a tokamak is to get the helium-ash out of the plasma.
Surprised no one mentioned it yet.
The scene with the artificial sun has to be pretty close to what the process looks like.
Let's be clear about one thing: we already have a nearly unlimited supply of nearly waste-free nuclear power in the form of breeder reactors: they destroy most of the radioactive waste and are at least an order of magnitude more efficient than current nuclear power plants in using nuclear fuel.
Why aren't they being used? Hard to say. The US claims it's because of nuclear proliferation, but that doesn't seem like a particularly strong argument. In light of the hazards of current fission reactors, and the difficulties of achieving fusion, maybe that's the third option.
Of course, the best solution would be to stick with the fusion power plant in the sky: it provides more than enough energy for our needs, with current technologies, if we only made a concerted effort to capture it.
Taiwanese companies will supply most of the core technologies that Beijing needs to build this artificial sun. In the past, Taiwanese companies have collaborated with Beijing in exporting weapons technology to Iran.
Extracting Deuterium from Sea Water is no threat to the sea itself, it exists for a tiny fraction of the total volume of sea water, one so small if all of it were removed, we probably wouldn't notice the sea level change anything outside the margin of error. Deuterium is not essential to the existence of water, so removing it in no way affects the quality or general properties of water.
Nope, because the reporter probably doesn't know what he's talking about. :)
When we have a working fusion reactor (expected somewhere in the second part of this century), the reactor itself of course won't provide infinite energy. But there is enough fuel on earth (and by extension on the moon) to last us a few million years. Longer than humans have been around. So in that sense, the first working fusion reactor will provide infinite energy, because we finally figured out how to build one. Once the first one is build, building dozens more is merely left as an exercise for the engineers.
Theoretically, when there is ignition, all the energy generated is pure profit. You don't have to add energy anymore, only fuel. So the energy output/energy input = infinite. But that is not the same as infinite energy. You still needs to add fuel. The amount of fuel injected in a reactor determines how much you get out of it. That is certainly high, but definitely less than infinite. And in practice, there will always be some losses. So the ouput/input ratio may be high, but not infinite.
There is also no need to worry about something like TMI or Chernobyl. In a classical nuclear reactor, all the fuel needed for years sits inside the reactor waiting to be used. In a fusion reactor, the fuel pellets are injected from the outside on a need to have basis.
I'm seeing predictable phaser rays. Stage two emitters activating now. Overhead capacitors to one-oh-five percent. Eeeeeh... its probably not a problem, probably, but I'm showing a small discrepancy... well... no... its well within acceptable bounds. Sustaining sequence.
Bzzzzzzt! Boom!
Oh dear! Gordon, get away from the...
Shutting down, attempting shut down, it's not, it's not shutting down, it's not...
B O O M!
Now it is time to bring the Sun Device over to Procyon II and speed the Chmmr Process up!
Star Control 2 - Try it if you haven't!
Ummm....we here in the US already had one. For 15 years actually. And that's the part that's unclassified. It's over at Princeton.
http://en.wikipedia.org/wiki/TFTR
So....I can see why this is printed as the 'first ever' in the source link. Last time I checked, Slashdot wasn't promoting Chinese Propaganda though. Maybe a correction should be made.....
The article glosses over a few important details, such as the fact that it's highly unlikely it will be able to produce more energy than it consumes. Thus while it might be able to use seawater to produce 300 times the energy per volume of gasoline, it probably takes about 3,000 times as much energy to extract the deuterium and generate that energy (the bit about getting the core temperature up to 300 million degrees is telling).
Especially if they're only spending $37 million US. I'd expect research and development costs to be at least 1000 times that. Of course, the article is too light on details to even begin to understand what the hell they're talking about.
"No problem. I have the capacity to do infinite work so long as you don't mind that my quality approaches zero."-Dilbert
There are no free lunches especially when it comes to nuclear engineering/physics. The promising thing here is that you have the potential to have a much higher power density and cheaper fuel since deuterium, in the form of heavy water recovered from the ocean, is not exactly hard to come by. Desalinization followed by reduction of the water to hydrogen and oxygen and then just gather ye heavy hydrogen in the form of deuterium and tritium. Heck, if they don't use the tritium in the reactor, even though it is a fine lower temperature ignition source, they could always sell it on the open market. It's quite valuable on its own.
"[I]t is a wise man who admits the limits of his knowledge or skill, and that pretending either causes harm." --Terry Go
fusion generates a lot of high energy radiation, but almost no radioactive particles. fission on the other hand leaves around all these radioactive isotopes, which will be radioactive for the next billion years. if a fusion reactor lost containment and went kaboom the facility might be destroyed and if so residents of the nearby city would have recieved about 5 years worth of x-rays and, some other hard radiation that few except astronauts have even been close to. but due to the short intense burst, the side effects would likely be nil. contrary to anything you may have heard about bruce bannon, the incredible hulk.
https://www.gnu.org/philosophy/free-sw.html
Actually it's a real diff. geom. theorem (2nd-year math undergraduate stuff) which is indeed applicable to tokamaks, since ionized particles stay (up to diffusion) "stuck" in magnetic field lines.
The Wikipedia article is indeed accurate, although very terse.
-- and yes, I AM a plasma physicist (or at least, was one for 4 years)
Working for necessity's mother.
Worst cases I can think off. Mind you, I haven't studied fusion reactor disasters, yet. So I could be wide off. However, it is my impression that not many people are worried about this. And that what I write down here is the prevailing knowledge. I have a masters degree in physics and worked on a tokamak for my masters thesis. For my PhD, I will be working on plasma's within a few weeks. So, that you know, I am not a crackpot scientist. English is not my native language, have patience.
You fill the reactor with as much fuel as you can, and you keep the machine going (i.e. you keep the magnetic field lines on, so that the plasma is confined and fusion reactions are going on.). Once enough fuel is inserted and energy is build up, you get an hydrogen bomb. An hydrogen bomb requires a classical fission bomb to get temperatures high enough so that fusion starts. But this can not happen accidently. In other to use a fusion reactor as a bomb, you intentionally have to add fuel to get it that far that it will explode. Any fusion reactor will have safety mechanisms. Now such things can fail. But since the fuel is sitting outside, safety systems can be designed that no fuel is inserted unless the operator (assisted by a computer) authorises fuel injection.
Contrast this to a fission reactor (the ones in operation now). All the fuel is present inside the reactor. The only thing operators can do is manipulate the burning rate. When something fails here all the fuel just keeps burning.
If something goes wrong in a fusion reactor, the reactor simply has to burn out. This happens rather quickly. there is no need to keep fuel inside that is needed more than for a minute or so. (Don't know how much or how long, just below the critical value for a explosion.) Fission reactors have fuel rods inside that lasted for years. Fusion reactors can be designed that fail safe means that no fuel is injected. You have to override such systems just to inject fuel, just to keep it going. In fission, fail save means that carbon rods are inserted between the fuel rods and you hope/pray that the fission reactions stop.
Okay, so what happens when everything goes wrong. No extra fuel is injected and the operators are no longer in control of the machine. It can not explode because there is not enough fuel inside. So forget Chernobyl and TMI. This means that everything outside the building is safe.
So, it can not explode. That leaves radiation. These are neutrons, gamma's (high energy light waves), high energy particles (alpha's mostly). There are other particle inside a reactor than alpha particles. Alpha particles (20% of the energy of a fusion reaction, 80% goes into the neutrons) are needed to keep temperaturs high. But this needs to be supplemented by external energy sources (another fail save, stop injecting energy.) Now these other particles, such as helium (this is the waste from fusion reactors. Even the waste has high economical value ! ) and carbon (eroded from the wall) have to be continually extracted from the reactor because the are bad for maintaining the required temperatures and energy levels. Alpha particles are stopped by a piece a paper. Don't worry about them. The neutrons are needed to generate tritium (tritium is radioactive, I think it has a 20 minute halve life inside the human body). But tritium will only be needed in the first few generations. Because using tritium is the easiest way to get towards a working fusion reactor. So the neutrons activate the reactor and the reactor will be stored for 50-100 years as high radioactive waste. Strontium, as you mentioned, although present in carbon and a waste product of coal plants is not present in fusion reactors. So these neutrons hit the wall, generate tritium and heat the wall/water in pipes and exit the chamber. (the water inside the chamber wall is the first water pipe system and generates steam in a secondary pipe system. From here you have a classical power plant of any kind.) Blocking those neutrons coming from the reactor chamb
if a fusion reactor lost containment and went kaboom
What do you mean by losing containment?
If the chamber bursts, the plasma comes into contact with the outside world. Everything in reach of the plasma is going to have a lousy day, but there isn't an explosion. Also, such an environment isn't exactly beneficiary to fusion reactions.
If the magnetic fields disappear, the plasma comes into contact with the wall. Again not very positive, for the wall and potentially for everything outside. Again, something which doesn't exactly promotes fusion reactions.
The only way, as I see it, for such a reactor to explode is to maintain confinement and keep adding fuel and fuel until it explodes.
An explosion is a lose of containment, but lose of containment doesn't imply an explosion.
In my other post, I did forgot to mention x-rays. But I have no idea about the amount of x-rays produced in a tokamak or in case of failure or the effect of it on humans, so I won't comment on that.
As to the radioactive particles from fission. It's the short lived ones that are dangerous, not the ones that are stable for a few billion years. Heck, we are living in a world filled with particles that have a 4+ billion years half live. Everything else has mostly decayed and disappeared since Earth's formation.
scentence ... I think you mean sentence .
t m
Well if you have bad things to say about the way things are done in china as a chinese,
you might experience something like this :
http://news.bbc.co.uk/2/hi/asia-pacific/4515197.s
The chinese rush to expansion and industrialization has a hunger to feed based on the
150 year captivity of hong kong, and I don't think it will be soon forgotten .
As a nation we need to re-evaluate sending most of our money out of the country .
Not just to china, but to all nations that have poor relations with us such as mexico .
If you have to buy your friends, they are not really your friends .
Ex-MislTech
google "32 trillion offshore needs IRS attention"
The temperature will fall off very very rapidly as the plasma expands. Also, fusion reactors can be built inside the same sort of vaults that fission reactors are built in. If the reactor explodes, there is no need to take a building with it. Messy.
a big enough black hole would keep swallowing matter and thus become even bigger.
Yes, big enough, and there's not enough matter in a laboratory to create such an object, nor do we have technology sufficient enough to compress the mass present in a laboratory into a space small enough to create a threatening black hole. (by "threatening" I mean one that wouldn't evaporate instantly)
There's something known as the Schwarzschild radius, which is more or less the "event horizon" of an object of a given mass. Only an object whose radius is itself smaller than its Schwarzschild radius can be considered a black hole. An object the size of, say, Mount Everest, has a Schwarzschild radius of about a nanometer. You would therefore need to compress Mount Everest into a volume slightly less than 4.19 cubic nanometers in order for it to become a black hole.
According to wikipedia, the Schwarzschild radius is roughly calculable with the equation: r = m * 1.48 * 10^-27, where r is the radius in meters and m is the mass in kilograms. A 1 kilogram mass would have a Schwarzschild radius of 1.48 * 10^-27 meters, while a proton is 10^-15 meters in diameter. So you'd have to compress 1 kilogram of matter into a space many orders of magnitude smaller than a proton before you'd have to worry about black holes. Like I said, we lack the technology...
Reinvent the wheel only at either a lower cost, greater effectiveness, or your own personal enrichment and satisfaction.
Disclaimer: I'm a plasma physicist.
:)
It turns out that the D-T fusion reaction yields a high-energy neutron. (In fact, these neutrons rattling around a shield/heating blanket around our reactor are what generates the heat we'll use to make electricity.)
However, there also exists a couple of favorible nuclear reactions which convert Lithium to tritium:
1) 6Li + n -> 4He + T + n + 4.5 MeV
2) 7Li + n + 2.5 MeV -> 4He + T + n
Effectively, the presence of Lithium, a very abundant element in the ground (more 7Li than 6Li), around the fusion reactor will generate _more_ T from fusion than is burned. We can therefore breed as much T as is needed from our existing supplies, which are = 20 kg for civilian use! A better way to think of fusion fuel is that they burn deuterium and lithium.
Without a fusion reactor, tritium can be created in trace amounts in the upper atmosphere through cosmic ray bombardment (perhaps ~50 kg distributed around the entire atmosphere), and in practical amounts by using heavy-water moderated fission reactors (deuterium bombardment, as you suggest).
A magnetically confined fusion plasma is a very tenuous beast. If all operating conditions are not satisfied, the background plasma requisite for fusion will not be created -- and if you go from 'good' to 'bad' operating conditions, the plasma snuffs itself out on the order of a confinement time (several milliseconds depending on device parameters).
has any scientist working on such a reactor deliberately simulated a total containment field failure?
Sure -- in modern research devices these failures happen for a myriad of reasons. Disruptions have happened a lot in the course of this research. On current devices, a disruption can be a 'no big deal' operation or force repairs; on a fusion reactor they really need to be avoided. Fortunately, the cause of showstopper disruption events are well known and techniques exist to stay away from the region of parameter space that causes them! There are also techniques to mitigate disruptions from unexpected failures (PDF warning).
think a popcorn kernel what happens when it reaches the right temperature? *pop*
There's a difference between temperature and energy density. For instance, if you blow out a candle you can snuff out the glowing wick with your fingers without burning them -- despite the wick being around 1000 K. The reason is that the candle wick doesn't have much energy stored inside. The same goes for a magnetically confined plasma. While the plasma has a very small tail in its energy distribution which allows thermonuclear fusion, the stored energy in the plasma itself is insufficient to, say, melt a building and set off an incindeary firestorm.
Break even (or the equivalent of break even) was achieved on the JT-60U tokamak in Japan in the late 90's (1998 I think). No fusion occured because tritium wasn't used in the reactor since I don't believe that JT-60U is equipped to handle tritium (for reasons of radiation). The performance of the plasma, being the energy confinement time, fuel density and ion temperature, was such that the equivalent energy gain had tritium been present would have been 1.25. Some of the problems with the current generation of machines are the use of copper coils rather than superconducting niobium-tin coils as copper coils require a tremendous amount of power to generate the magnetic fields necessary to confine the plasma (typically 3-5 Tesla at the machine major radius). The coils on the small tokamak I work on are copper and require a few tens of kilowatts of power to generate a 0.7 Tesla magnetic field we use and we have the benefit of having very small coils. The largest machines, where the copper coils are much larger (about 3m diameter, roughly compared to .4m on our machine) require hundreds of megawatts to generate their magnetic fields. Superconducting coils present the ability to greatly reduced the power required to operate the machine.
The problems with plasma performance are generally centered around energy loss from the plasma, through particles, heat or EM radiation. Radiation isn't a big problem, but particle and heat loss are. The plasma is very turbulent and this turbulence leads to what is referred to as anomalous losses, anomalous in the sense that they are not well explained by theory and are orders of magnitude larger than what is predicted by theory. These losses can be reduced by elaborate modes of operation, generally referred to as H-modes (H meaning high confinement). There are some other drawbacks to these modes, but without getting into much detail, the scaling of confinement with various parameters of the machines shows that a machine the size of ITER (http://www.iter.org/ should have a plasma performance that is good enough to achieve a fusion power gain of 10, that is 50 MW of heating to the plasma and 500 MW of fusion power output. The ideal would be to be able to turn off the plasma heating, but if ITER works as predicted it will be very good.
There is also some concern over what will happen to the alpha-particles produced after they give up there energy to other species in the plasma. They have to be removed as they will degrade the plasma performance. I believe that there is an idea of a way to remove them, but this is outside of my area of research.
There are other problems with an actual power producing machine. Most of these are engineering problems and have to do with such things as building some sort of lithium blanket that can withstand being bombarded with 14 MeV neutrons, breeding and extracting the tritium fuel and handling the tritium fuel.
To quote F.F. Chen: "A plasma is a quasineutral gas o charged and neutral particles which exhibits collective behaviour".
A burning plasma is a nearly fully-ionized gas in which the fusion power captured by the plasma keeps the plasma hot. It can also be called a self-heating plasma.
Mm, I'm late to this discussion, but...
Point one: tokamaks run their plasmas at about 1 millionth of atmospheric density; the rule of thumb is 10^20 particles/meter^3. This means the plasma is in a vacuum vessel.
Point two: for DT fusion, you've always got neutrons coming from the reactions. And they're fast neutrons, which means they'll react with the Nickel in stainless steel to form Cobalt-60, which is a gamma emitter. But that's stuck in the wall, and you'd want to use a different material for your walls anyway.
Point three: if magnetic containment fails and the plasma hits the wall, the plasma just dumps its thermal energy into the wall, and fusion can no longer be sustained. This happens in experiments all the time, though they try to avoid it. At worst, this could rupture the wall.
Point four: I haven't studied this in detail, but if the wall ruptures, then there will be air sucked _into_ the reactor to equalize pressure. In a real plant design, you'd probably have separate air circulation for this region of the plant, but for disaster analysis you'd assume a small amount of what's inside the reactor gets outside into the world. The only radioactive stuff would be tritium, which is relatively harmless, but still a problem.
So if a fusion reactor fails, nothing catastrophic happens. You need extreme extreme density to have an H-bomb. This is what they do with in Inertial Confinement Fusion, compact DT ice with lasers. I don't have my notes right now, but that resultant density is a whole fricking lot more than 10^20 per meter^3.
My fusion professor had an essay question that went like this: The devil comes to see you, offering a choice of three things in exchange for your soul: a room-temperature superconductor, a full understanding of plasma transport phenomena, and a resilient first wall material. Which do you choose and why?
The concept of the question is that any one of those three things would give us a viable fusion reactor. They're all technical issues.
1) Superconducting magnets. Tokamaks rely on SC magnets to create their strong fields. With current technology, these magnets have to be cooled with liquid helium. One obvious problem is that a coolant failure would be bad, and it's expensive to keep a cold thing cold while it's next to a very hot thing. Another is that the magnet coils are in a position where they experience a lot of neutrons, damaging the material. So why would a room temperature superconductor be good? It would eliminate the cost of coolant and alleviate concerns about coolant failure, for one. Removing all the cooling facilities would also allow the tokamak to be shaped for better efficiency.
2) Plasma transport. This refers to heat conduction through a plasma. It surprised me to learn that we still do not understand plasma transport. The calculated heat flux out of the plasma via electron motion is off by orders of magnitude. And of course, the error goes the 'wrong way'; we calculate much less heat loss than actually occurs, and we want to keep heat in the plasma to maintain the reaction. Furthermore, we don't fully understand plasma instabilities, as confined plasma likes to do all sorts of wacky things.
3) The first wall. The 'first wall' is the wall right next to the plasma. In DT fusion (the only variety considered to be commercially viable) you produce 'fast neutrons' which really mess up most materials. The canonical example is stainless steel, which will deteriorate rather badly and produce Cobalt-60 in the bargain. So there has been interest in more exotic materials like Vanadium and Molybdenum. The problem here is that at fusion temperatures, materials tend to bleed off particles, and anything that's not D or T in the reactor poisons the reaction and reduces the yield significantly.