The helium bubble: prospects for 3He-fuelled nuclear fusion
Is the Moon our next energy reservoir? Is the future of humanity to be powered by nuclear fusion with helium-3 mined from the moon and brought back to earth?
In this paper, we review the current status of nuclearfusion research, the merits and advantages of aneutronic fusion based on 3He and the current state of knowledge.
When it comes to energy, nuclear fusion is often referred to as the holy grail as it would provide a source of abundant energy with no risk of meltdown, plentiful resources and no greenhouse gas emissions. The main candidate fuel for future reactors is a mixture of deuterium and tritium which fuses to form energetic neutrons and helium.
As neutrons can damage materials and limit their lifetime in the extreme environment of a fusion reactor- where the fuel needs to be brought up to 150 million degrees- other potential fuels have been proposed which would strongly reduce or eliminate neutron formation. Among them, helium-3 is often mentioned since the discovery that the Moon contains significant amounts of this species, which is virtually non-existent on Earth. Therefore, Helium-3 is a reason often mentioned to go back to the Moon and justify space resource utilization.
After 70 years of intense research, deuterium-fusion has proven to be very difficult to master and the ability to use it in an economically attractive way is still a long shot. Unfortunately, in many aspects, helium-3 fusion is much harder to achieve. As a result, we show that this technology, if demonstrated, is most likely only to be considered fora second or third generation of fusion power plants and given the current schedule of fusion demonstration and deployment, is unlikely to appear this century.