Keywords: fission, fusion neutrons, fusion hybrid, fissile material breeding, plasma, nuclear safety, nuclear proliferation, nuclear power, nuclear energy
A promising approach to safe, proliferation resistant production of nuclear power
With the world population reaching about 10 billion by mid-century, the requirement for carbon-free energy (estimated at 30 terawatts) to meet global needs will indeed be daunting. A sizable portion of this power is expected to come from nuclear sources fuelled by fission and/or fusion breeding. Although a great international effort is currently underway aimed at producing pure fusion power, the fact remains that such reactors will initially be characterised by a rather modest gain factor, 'Q' (the ratio of fusion power to injected power), putting in question their economic viability and potential impact on the energy crisis. It is well known, nevertheless, that fusion reactions are neutron rich and energy poor, while fission reactions are energy rich but neutron poor. As a result, it has occurred to many researchers over the past several decades that a fusion hybrid in which fusion neutrons are used to breed fissile material, thereby serving as a 'fusion fuel factory', might very well address the impending energy shortage. In this paper, we take a somewhat different approach. We propose a system in which the fusion neutrons from a fusion reactor operating at Q-value slightly larger than unity are used to drive an energy-producing blanket in which uranium-233 fissile material is bred from thorium-232 and simultaneously burned to produce energy. It will be a steady-state operating system with no criticality invoked, thus providing a measure of safety as well as potential elimination of proliferation hazards.