Theoretical evaluations of small-scale nuclear power systems

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Nuclear power is often frowned upon by the public because of a lack of an understanding of the technology. Nuclear power has been investigated thoroughly on a large scale, but has yet to be explored on a small scale. In order to find a safe and sustainable nuclear fuel for small-scale and short-term power production, thorium-232 (Th-232) has been proposed as a fertile material for a portable accelerator driven system (ADS) and tritium has been presented as a suitable beta source for a betavoltaic battery. In this work, Monte Carlo N-Particle Transport code (MCNPX) and ORIGEN 2.2 were used to develop the theoretical framework for future experimental design. Th-232 and uranium-238 (U-238) were irradiated with a monoenergetic neutron source over an energy range from 2 MeV to a maximum energy of 16.5 MeV. Neutron absorption profiles for Th-232 and U-238 were calculated and compared for an ADS. ORIGEN 2.2 was used to calculate the total power output, actinide production, and fission production of both fertile materials. Similarly, lithium-intercalated graphite was irradiated with protons and neutrons over the same energy spectrum to breed tritium. MCNPX was used to calculate the proton and neutron absorption profiles of lithium-intercalated graphite to determine optimal irradiation conditions. The results indicate that Th-232 is the superior fertile species in terms of absorption, power output, actinide production, and fission product production. Additionally, the data suggests that a monoenergetic neutron source irradiating lithium-intercalated graphite would provide the maximum number of lithium reactions to produce tritium. If these systems were produced, they would be ideal candidates for small-scale power production and would have countless applications.