Thanks again for taking the time to submit your Stump the Scientist questions! We had some great questions submitted this week, hope you enjoy this one!
Question from fan Nicolas Roux:
“How close are we to making nuclear fusion a reality?”
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Response from Chief Scientist Jim Bray:
Nuclear fusion is the process whereby 2 lighter atoms combine (fuse) their nuclei to produce a heavier atom. This process often produces a lot of energy for lighter combining atoms, since some mass is converted to energy during the fusion process. We can say that nuclear fusion is certainly a reality now, since it provides the energy that causes all the stars shine; all stars are powered by fusion of light elements like hydrogen. It is also a reality here on earth, since it is the method by which thermonuclear weapons (H-bombs) work. So we now get to what we suppose Nicolas is asking: how close are we to making nuclear fusion a viable controlled power source for commercial power needs on earth?
This is a very hard problem because, in order to fuse the nuclei of atoms of a material, we must raise the temperature to many millions of degrees. There is no container for such temperatures, so physicists resort to using containing magnetic fields or quick energy inputs to try to raise the temperatures before the hot materials escape. The experiments and equipment are so complex and expensive that many nations have banded together to make a large experiment (using magnetic fields) called ITER in France. This experiment will not begin until around 2020 and will not produce commercial power. It will take a number of years after that to produce a plant to make commercial power, so we can guess that at least 25 more years will be needed. Another experiment in the US at Lawrence Livermore National Lab is producing fusion by quick energy input (by lasers) into materials. It is supposed to begin working this year, but it is also not going to produce any commercial power. 25 years might also be a good guess at how long it would take to commercialize that approach. So, in summary, no one knows for sure when fusion will be a reality for commercial power on earth. The problem is a hard one and the equipment is very expensive. The numbers I have given are just guesses.
