Amanda Bachmann, Ph.D. Candidate
Dr. Madicken Munk, Director of Research
November 2, 2023 | 8:00am - 10:00am CST
This final examination will be held in 101A Talbot Laboratory.
A Zoom link is provided below for those who could not attend in person
Meeting ID: 896 0967 7749
Investigation of the impacts of deploying reactors fueled by high-assay low enriched uranium
ABSTRACT: The US is looking into the deployment of advanced reactors that require uranium enriched between 5-20% 235U, often referred to as High Assay Low Enriched Uranium (HALEU). There are no commercial facilities in the US to produce HALEU, prompting questions of how to create a dependable supply chain of HALEU. HALEU can be produced through two primary methods: downblending High Enriched Uranium (HEU) and enriching natural uranium. The amount of HEU available and impurities present in the HEU limit downblending capabilities. The Separative Work Unit (SWU) capacity and amount of natural uranium available limit enriching natural uranium capabilities. To understand the resources necessary to commercially produce HALEU with each of these methods, we can quantify the material requirements of transitioning to HALEU-fueled reactors. The work completed in this dissertation demonstrates a methodology for understanding the effects of deploying HALEU-fueled reactors in the US.
This is completed by modeling the fuel cycle transition to different advanced reactors and different fuel cycles, then performing sensitivity analysis and optimization on one potential fuel cycle. This analysis provides information on the materials and resources (such as HALEU mass and SWU capacity) required to support these reactors, and how the transition parameters affect these requirements. This information can be used to develop the necessary infrastructure and supply chains. Furthermore, this work explores how the HALEU production method (enriching compared with downblending) affects reactor performance. This work is performed by modeling two HALEU-fueled advanced reactors to evaluate the performance of downblended HEU. Different HALEU-compositions are compared based on the k-eff , β-eff , energy- and spatially-dependent neutron fluxes, as well as the fuel, moderator, coolant,and total reactivity temperature feedback coefficients. Understanding the effects of using downblended HEU in reactors provides context on how much the fuel impacts reactor performance and operating parameters.