Electronic Theses and Dissertations

Date

2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Chemistry

Committee Chair

William Alexander

Committee Member

Tomoko Fujiwara

Committee Member

Yongmei Wang

Committee Member

Timothy Brewster

Committee Member

Charles Garner

Abstract

Currently, the process of determining the enrichment levels of uranium for enrichment processing plant is a long and involved process, requiring samples to be collected, shipped, and then processed at a separate facility. This system takes weeks to get results about a critical process. Lowly enriched uranium is used to make fuel rods for nuclear energy, but highly enriched uranium is used to make nuclear weapons. To reduce the time it takes to determine enrichment, we explore creating an alpha detector that is able to connect on-line at the enrichment plant and determine enrichment from the source gas. To enrich uranium, it is processed to uranium hexafluoride (UF6), which when heated, transforms to a gas, and is pumped through a series of gas centrifuges. UF6 is known to be very corrosive so any alpha detector would have to be passivated to protect it from attack. We proposed protecting the detector with a self-assembled monolayer (SAM) chemisorbed to gold. However, there is not much literature available on how UF6 reacts with different functional groups. To investigate this, we used reflection absorption infrared spectroscopy (RAIRS) to monitor a SAM surface while it was exposed to UF6 gas. We exposed three different surfaces to UF6 gas: a hydrocarbon, a fluorocarbon, and an amine surface. All three surfaces showed a high degree of disorganization post-exposure, resulting from UF6 oxidizing the thiol bond of the SAM. The amine surface showed the most reaction with UF6 due to the attraction between UF6 and the lone pair on the terminal amine group. Both the hydrocarbon and fluorocarbon surface had UF6 adsorb to the surface, but it did not appear to react with either surface.

Comments

Data is provided by the student

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Embargoed until 7/11/2023

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