A design of the same type for helium fusion would require higher temperatures and even more massive sizes. However, Close’s objections are based on conventional fusion reactors, such as ITER, an international project under construction in France, which will weigh three times as much as the Eiffel Tower and reach temperatures of 150 million degrees centigrade. “Helium-3 has no relevance for fusion,” stresses Close to OpenMind “Nothing has changed in the laws of physics since my 2007 article.” Although the physicist believes it is possible for us to see the development of lunar mining, “there is no point in going to the Moon for helium-3 if your goal is to make fusion.” New strategies for fusion In summary, Close labelled the idea of generating electricity from lunar helio-3 as moonshine. In practice, Close pointed out, deuterium would tend to fuse with itself to form tritium, which would then react again with deuterium as in conventional fusion, producing neutrons. In 2007, Close wrote in the journal Physics World that “d euterium reacts up to 100 times more slowly with helium-3 than it does with tritium,” which would require much higher melting temperatures than in current reactors. The main objection to fusion with helium-3 is summed up by Frank Close, a physicist from the University of Oxford. However, for Wright, vast improvements in fusion technology will still be needed “before we have to worry about mining.” Credit: Oak Ridge National Laboratoryĭespite the major obstacles, “there may be some chances to use helium-3 as a second-generation fuel,” fusion physicist John Wright of the Massachusetts Institute of Technology tells OpenMind. Aerial drone image of the ITER construction site. To this would be added the difficulty and the cost of transporting it to Earth. In contrast, for billions of years the Moon has accumulated an incredible amount of this material in its surface layer, although at such a low concentrations that it would be necessary to process enormous quantities of regolith to harvest it by heating it at 600 ☌.
This isotope comes mostly from the solar wind, but the Earth is protected under the shield of its atmosphere and its magnetic field. The problem is that helium-3 is extremely scarce on Earth. In addition, it is possible to capture its energy to produce electricity directly, without the need for a water heating process to move turbines, as in current nuclear fission plants. However, the technological development needed for it to be a practical and energy-efficient option still keeps researchers busy, and it is not an entirely clean energy: the fusion of deuterium and tritium produces neutrons, particles that cause radioactive contamination and that cannot be contained with electromagnetic fields, since they lack an electrical charge.Īgainst this, helium-3 (a non-radioactive isotope of the gas used to inflate balloons) offers remarkable advantages: its fusion with deuterium is more efficient than deuterium-tritium and does not release neutrons but protons, which can be easily contained thanks to their positive charge. The nuclear fusion of light atoms, such as the hydrogen isotopes deuterium ( 2H) and tritium ( 3H), has been seen for decades as the energy source of the future, inexhaustible and much less polluting than the fission of heavy atoms such as uranium. However, more than 30 years later, not a single gram has been collected yet, and there are those who say that it will never happen, because -according them- helium-3 has only served to inflate an enormous balloon of unfounded speculation. The analysis of the researchers, based on samples collected by the Apollo missions, triggered a fever for this new lunar gold, which would be worth billions of dollars for those who controlled it. According to the study, mining it would be a profitable undertaking: the energy produced by the helium-3 would be 250 times greater than that needed to extract this resource from the Moon and transport it to Earth, where the lunar reserves of helium-3 could supply human needs for centuries. In 1986, scientists at the Institute of Fusion Technology at the University of Wisconsin estimated that the lunar “soil”, called the regolith, contains one million tons of helium-3 ( 3 He), a material that could be used as fuel to produce energy by nuclear fusion.
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