Fusion?

[Fake Messiah]

I've also heard that ITER alone will use up about half the world's helium stock so cool the massive super-conductive coils... but fusion generates helium, so maybe we can restock on that....

ITER will consume is all supply of Earth's tritium (H3 or T for short) because it does not occur naturally since it "dies" after 12 years and a reactor may use up 100 kg per year.

ITER will need lots of helium but not that much. First of all helium is not a rare gas if we can afford to fill the world’s balloons with it. Actually, balloons account for only 16% of helium use. Already cooling of semiconductors accounts for 33%, and the rest is used for industrial and scientific purposes. It is estimated that ITER will lose 48 tonnes of helium a year, about 0.15% of the world’s current consumption. But if eventually fusion produces a third of the world’s power, those reactors would need the world’s supply of helium for a whole year just to start up. At some point the helium losses, say, 10% of the inventory, would exceed what comes from natural gas. Although helium is one of the products of the D–T reaction this “ash” is a negligible contribution to the total demand.

In 1986, compounds were discovered that became superconducting at a critical temperature as high as 30 K. Since then, research to find better materials has been intense. The goal was to get the critical temperature above 77 K, the point at which nitrogen becomes liquid. Liquid nitrogen is much, much cheaper and easier to produce than liquid helium, which is liquid below 4 K. The 73°C difference between 77 and 4 K does not seem much. We encounter such a change every time we boil a cup of coffee. However, since one can never go below absolute zero, it is the distance from absolute zero that is important. Seventy-seven kelvin is 19 times farther from 0 K than is 4 K; and, of course, there is no shortage of nitrogen. The goal has already been achieved; three superconductors have been found that work at liquid nitrogen temperatures. The record as of 2009 is 135 K, well above 77 K. Typically, the compound is complicated: HgBa2Ca2Cu3Ox. Until searches can be made by computer, finding new compounds will be slow; but it is a reasonable expectation that large-scale production of a high-temperature superconductor will be possible by the time DEMO is built.

Also in advanced designs, the helium is eliminated, resulting in a self-cooled lithium lead breeding blanket, in which Pb-Li does all the cooling. It may take a lot of power to pump Pb-Li fast against the drag by the magnetic field. The possibility also depends on the development of the wonder-material SiC/SiC, which can operate at 1,000°C and contain a higher temperature fluid than other materials.


What is ITER designed to do? The primary goal is to produce, for the first time, a “burning” plasma. That is, a plasma that will keep itself hot once it has been heated to several hundred million degrees.
Q value of at least 5 is needed for burning or ignition. To get a safety margin, ITER is designed to produce a Q of 10, where Q is the ratio of energy out of the plasma to the energy put into the plasma from external sources. Q = 1 is scientific breakeven (energy in equals total energy out). So far JET is the best but only Q=0.65.

However, tokamaks may not be the machines ultimately chosen for fusion reactors. Stellarators, which do not need large currents, do not suffer from disruptions. The reason that tokamaks are now prevalent is that they gave the best initial results, and there has not been enough money to study other toruses to the same extent.

So, that makes the nice number of 145 billion years.... ok, I guess there's enough to outlast the sun's demise!

Maybe the estimation I heard was concerning lithium....

You probably mixed it up with future designs of fusion reactors. Right now, we are trying to fuse deuterium (D) with tritium (T) to get helium plus an extra neutron. That neutron carries away most of the energy generated, but it also causes some radioactivity, but much less than in fission. For the future, there are other advanced reactions involving helium-3 (He3), lithium, or boron which are completely free of radioactivity. Note that lithium and boron are abundant and safe elements on earth. Indeed some day the inhabitants of this planet will look back at the clumsy magnetic bottle, the D–T tokamak. The tokamak will seem like an old IBM Selectric typewriter with font balls compared to Microsoft Word on a 2-GHz notebook computer. The deuterium–tritium reaction is a terrible fusion reaction, but we have to start with it because it is easy to ignite. These future magnetic bottles will hold denser, hotter plasma for a longer time.  Then we can use reactions that do not produce the intense flux of energetic neutrons that plagues D–T reactors.
There is better reaction but for now more complicated the D-He3 has sizeable reactivity at low temperature and produces no neutrons and this is an almost clean reaction. Deuterium - helium3 reaction is also considered to have smaller reactors so that some people speculate we could make very fast spaceships on nuclear fusion that could take us to the nearest stars in only few decades. But the main problem is He3 does not occur naturally on Earth. It can, however, be mined on the moon. It is estimated that there are a billion tons of He3 just under the surface of the moon, enough to supply the world for 1,000 years if it could be brought down here. And when it comes to spaceships it is calculated that they could be refueled on some gas giant planets like Saturn that also have lots of He3.

Far too many people think evolution is wrong and they are here because some fucking 'god' played in the dirt.  You have to write them off.

Maybe they are the first people to revolt on streets since pope and imams told them to fight against global warming. It seems that atheists are those that need to wake up from their inertness. Just imagine one day atheists and theists all joined together on streets, like bunch of gays once did protesting for cure of AIDS, but now for their governments to provide for pollution free world in which there is no mass murder of people by burning oil, coal and gas.