Theoretical evaluations of small-scale nuclear power systems

"December 2013.""A thesis presented to the Faculty of the Graduate School at the University of Missouri In Partial Fulfillment of the Requirements for the Degree Master of Science."Thesis supervisor: Dr. Matthew Bernards.[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.Includes bibliographical references (pages 51-52)