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China Claims Successful Fusion Power Test
SeaDour writes, "China claims to have carried out a successful test of its experimental thermonuclear fusion reactor. But what exactly made this test 'successful' is not clear. From the article: 'Xinhua cited the scientists as saying that deuterium and tritium atoms had been fused together at a temperature of 100 million degrees Celsius for nearly three seconds. The report did not specify whether the device... had succeeded at producing more energy than it consumed, the main obstacle to making fusion commercially viable.'" China is a participant in the 10-nation ITER project to build a fusion reactor in the south of France by 2015. The article quotes the research head of ITER as saying, "It was important for China to show that it is part of the club. Here are English language versions of the Chinese news release: announcement, background.
Nah, you want it to get as hot as possible. Higher temperature leads to more reactions in the fuel, which in turn leads to greater effeciency. Part of the problem is getting the fuel that hot in the first place, and keeping it together long enough to fuse.
Side note: while 100 million degrees sounds awfully hot, we're talking about a tiny amount of fuel here. The usual figure quoted for a hypothetical commercial reactor is about two grams of fuel in the core at any given time. The reactor itself doesn't get anywhere near that hot, even in the event of a full loss of containment.
Erotic is when you use a feather. Exotic is when you use the whole chicken.
It was successful in that it fused deuterium and tritium. Of course, the break even point doesn't matter. To be economical, the reactor realistically has to hit ignition, which only the ITER could hope to do.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
Achieving a net energy gain is not the main obstacle to making fusion commercially viable. That has been done quite successfully. There is no problem passing break-even. It is ignition we are trying to achieve now. That is, a fusion reaction which produces enough heat to cause more fusion, provided enough fuel. If you're going to write an article about fusion, at least know something about the state of the field. Journalists should all be required to read the relevant wikipedia articles before publishing something about science.
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wait... not that kind of sig.
Magnetic containment. This isn't like fission reactions. There isn't a "pile." Just a couple of grams of non-radioactive deuterium and radioactive but fairly benign tritium. In the event that the magnets somehow fail, the reaction will stop, with just a bit of erosion on the sides of the reactor.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
It's a superconducting tokamak.
The new part is the fact that it uses superconducting magnets. Tokamaks have been used since the 70's.
This post climbed Mt. Washington.
But that is the law of physics. The extra energy comes from the mass which is converted to energy. Had it said "producing more mass/energy than it consumed", then that would be against the laws of physics.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
Though ITER is being built soon, it's being designed as its going up. I'm involved with creating an H- ion beam to inject the plasma (called neutral beam injection). The idea is to fire a high energy beam of neutral hydrogen into the plasma to heat it up (neutral so the atoms can travel through the containment magnets without deflection).
So even if the Chinese managed to build a reactor that beats previous records, it's a long while before fusion powers your home. Nevertheless I consider Fusion research to be one of the most important fields; it takes no imagination to understand what it would mean if nations could be powered on water.
Actually, you don't lose mass when you burn something. Chemical combustion converts potential chemical energy into heat, but the end products mass as much as the starting ones. All the energy in a gallon of gas is the energy that went into producing it.
But technically yes, when you talk about fusion reactors you should say "converted more energy from mass than it took to fuse said mass". So the phrasing from the article/summary is technically in error, but most people who know their physics can grasp what they actually mean.
Erotic is when you use a feather. Exotic is when you use the whole chicken.
Actually, you don't lose mass when you burn something. Chemical combustion converts potential chemical energy into heat, but the end products mass as much as the starting ones.
Actually, you always lose relativistic mass when you release potential energy. A gallon of gasoline is more massive than the sum of the masses of its individual atoms (but not by much), due to the electromagnetic potential energy of the chemical bonds. By general relativity, any place in space with a nonzero mass or energy density is warped. Thus, the potential energy (think of it as being contained in the electromagnetic field between the atoms) actually contributes slightly to the effective mass of the system.
The fraction of relativistic mass lost when you burn a gallon of gas is probably so small as to be unmeasurable by any known measurement device, but it's there (at least if GR is correct).
Well, the "Me so horny" prostitute was Vietnamese (from the movie Full Metal Jacket), and it's the Japanese that have problems pronouncing Ls, not the Chinese. So, besides mixing up three different asian countries with distinct languages and cultures, your ethnic insult was spot on. Way to go!
That's actually one of the main engineering problems, it's as lot easier to turn some fuel into a simulated sun than than it is to poke some fresh fuel into the middle of one.
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Word is that Dr. Farnsworth of Futurama was actually named after the Dr. Farnsworth who invented the CRT TV and the Fusor reactor.