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Raccoon said:However, I still don't understand how scientists can create fusion and expect it to stop on its own.
[/ QUOTE ] Thermal conduction through plasma is 10,000 times higher than that of the best solid or liquid thermal conductor we know of - if the plasma ever managed to get out of the magnetic bottle containing it and actually touch the reactor walls, it would immediately cool to below the minimum fusing temperature and quench the reaction ( within microseconds or less, depending on the size of the reactor ). It's one of the safest and cleanest forms of energy production you can get. Afterall, keep in mind that most fluorescent lights in your home operate at or above the surface temperature of the sun....and you're not too worried about those causing a meltdown even if they broke open during operation. The plasma in both your fluorescent lights and that of a fusion reactor is so rarified that it just isn't a danger in this manner.
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Raccoon said:The type of fusion they're trying to create is for the purpose of propetual energy generation...
[/ QUOTE ]No, actually not. Perpetual energy is not a viable idea from the perspective of classical physics and seeming violations of this law from a quantum mechanical perspective are likely the result of energy just being transferred from one unknown system into the one being observed at the time any seeming 'violation' of that law is witnessed.
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Raccoon said:...more energy is created than is used in creating it. If this is so, fusion should be able to grow on its own, and infinitely so.
[/ QUOTE ]No, not quite. More energy is released than is used in starting the fusion reaction - it's not created from out of nowhere. It's actually releasing the excess binding energy stored within the Deuterium and Tritium fuel's nuclei ( in the form of the Nuclear Strong force ) which is then released when the two hydrogen isotope nuclei fuse - it basically takes less total energy to hold toegether the newly fused hydrogen fuel nuclei ( which have now been fused into helium ) than it originally took to hold together the individual hydrogen isotopes on their own. It's by no means perpetual energy generation ( just like burning gasoline or coal is not perpetual energy generation ) - it's just a different method of extracting a portion of the energy contained within a substance and putting it to practical use. And just like burning coal or gasoline requires a spark ( energy ) to initiate the release of even more energy stored within the chemical bonds of those fuels, fusion requires it's own spark of sorts ( anything that can heat the reactants to over 1 - 10 million degrees kelvin ) in order to release some of the energy stored within its nuclear bonds so that we can harness it and put it to constructive use.
It is by no means a bomb and couldn't be turned into one despite the seeming similarity in the way energy is being released between it and an H-bomb. Sort of like worrying that your car will blow up your house everytime you start it just because miniature, contained, and channelled explosions are taking place within the combustion chambers of your car's engine....it just isn't going to happen because it's not designed to release energy in a mass, uncontrolled explosive manner. Just like a fusion reactor, it is designed to release relatively small, steady, and controlled amounts of energy ( compared to that of a nuclear bomb ). And the best thing is, after letting the reactor waste sit for about 20 years you can drink it and suffer little or no ill effects ! /ubbthreads/images/graemlins/smile.gif The low-level radioactive emissions from spent fusion fuel decay quite quickly ( which sits a lot better with me than the epochs that it takes to wait for spent Fission fuel to decay into something equally palatable ). Nice and clean energy.