The fuel cycle of the light-water reactor system that currently dominates worldwide nuclear power is quite complex. It involves exploration for and mining of uranium, milling into U₃O₈ yellow cake, processing into UF₆, complex chemical enrichment, fuel fabrication, fuel assembly, transportation to the reactor, removal and interim storage of spent fuel, then permanent disposal of high-radiotoxicity waste.

In contrast, DBI reactors are fueled primarily by thorium oxide that does not go through complex chemical processing or enrichment. In the core it is transmuted to the man-made fissile ²³³U then burned. Thorium is preferable to uranium for many reasons, including:

1. Compared with uranium fuel cycles, using thorium as nuclear fuel produces no plutonium and much less other transuranic isotopes.
   
   
2. In nuclear applications, thorium’s radiation stability and thorium dioxide’s higher thermal conductivity suggest that thorium fuels have greater potential safety and fuel durability than uranium dioxide or even mixed uranium/plutonium oxide nuclear fuels.
   
   
3. Thorium is more than three times as abundant in nature as uranium, reflecting the differences in the half-lives of ²³²Th (1.4×10¹⁰ years) and ²³⁸U (4.5×10⁹ years). Based upon the U.S. Geological Survey’s known reserves worldwide, energy from thorium could match the current level of global energy consumption for at least 500 years, and perhaps 2500 years with improved technologies.
   
   
4. The Encyclopedia of Science and Technology says that the energy available from the world’s supply of thorium has been estimated as greater than the energy available from all of the world’s uranium, coal, and oil combined, and the system of ²³²Th/²³³U gives promise of complete utilization of all thorium in the production of atomic power.

A May 2000 report of the International Atomic Energy Agency (IAEA) has identified many incentives for thorium’s use, including public concerns about highly radiotoxic and long-lived waste and the large stockpiles of plutonium that can be used for weapons proliferation. Other aspects in considering thorium-based fuel cycles include the potential to breed ²³³U and incinerate long-lived radiotoxic isotopes, and the economic motivations needed for nuclear plant owner/operators to invest in commercial changes.