Doctoral Dissertations

Orcid ID

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Nuclear Engineering

Major Professor

G. Ivan Maldonado

Committee Members

Nicholas R. Brown, David C. Donovan, Paul W Humrickhouse


Fusion neutronics plays a critical role in the design and operation of fusion reactors. However, there are a number of challenges associated with fusion neutronics that must be overcome in order to help achieve practical and sustainable fusion energy. The primary objective of this project is to develop and demonstrate a broad neutronics analysis capability in support of system studies for U.S. concepts such as the Fusion Nuclear Science Facility (FNSF). According to a detailed TBR analysis that included an examination of reaction rates and the impact of facility (FNSf) components on neutron spectra and TBR, Li-6 will generate the vast majority of the tritium. It was also shown that the DCLL design is capable of producing TBR above the minimum requirement. A supporting TBR analysis on GA's SiC-based GAMBL blanket design during the investigation of multiple blanket concepts showed that, under the assumption that the model's only modification is the substitution of SiC-SiC for MF82H, a SiC-SiC structure is capable of a slightly greater TBR than a ferritic structure. A one-dimensional TBR study of solid breeders was also conducted to better understand the impact of different blanket materials on the TBR performance of solid breeders and beryllium-based multipliers. The findings indicated that the majority of solid breeders are capable of producing a TBR that is greater than PbLi, with RAFM and tungsten having the greatest influence on its reduction from the maximum achievable value. A high-fidelity solid breeder TBR analysis was also carried out for validation of results and to establish bias to evaluate TBR predictions. The findings of the investigation demonstrated that 1-D models are very useful for general scanning, such as choosing the most productive solid breeder material. Finally, OpenMC's R2S workflow was used in the FNSF model for the shutdown calculations for the suggested maintenance scheme in order to support the testing and development of OpenMC methods. Tungsten contributes the most to photon emission and dose and also produces isotopes that will last through the maintenance window. Po-210 and Hg-203 (respiratory hazards) are produced in PbLi at a rather high rate, which could be problematic.

Files over 3MB may be slow to open. For best results, right-click and select "save as..."