Maximizing specific energy by breeding deuterium

Abstract

Specific energy (i.e. energy per unit mass) is one of the most fundamental and consequential properties of a fuel source. In this work, a systematic study of measured fusion cross-sections is performed to determine which reactions are potentially feasible and identify the fuel cycle that maximizes specific energy. This reveals that, by using normal hydrogen to breed deuterium via neutron capture, the conventional catalyzed D-D fusion fuel cycle can attain a specific energy greater than anything else. Simply surrounding a catalyzed D-D reactor with water enables deuterium fuel, the dominant stockpile of energy on Earth, to produce as much as 65% more energy. Lastly, the impact on space propulsion is considered, revealing that an effective exhaust velocity exceeding that of deuterium-helium-3 is theoretically possible.This reaction has a cross-section of ∼ 0.3 barns for thermal neutrons [24]. Though the cross-section may seem small compared to D-T fusion, this reaction is actually

Operational Costs of He3 Separation Using the Superfluidity of He4

“…The nearest source of extraterrestrial He3 is on the surface of the Moon. Samples of lunar rocks and dust containing He3 were brought to Earth by the Apollo missions (11,12,14,15,16,17) and the Russian probe Luna 16. The measured concentration of helium isotope did not exceed 20 ppb (Table 1).…”

“…The reason that may generate demand in the future is global warming and the associated demand for carbon dioxide emission-free energy sources, in particular the fusion of deuterium and He3. Both isotopes appear to be potentially very attractive as nuclear fusion fuel because no neutrons are generated in the reaction and the process is highly energy efficient [16]. Currently, almost all of the liquid He3 used in the industry comes from the decay of man-made tritium.…”