Award Date

5-15-2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

First Committee Member

Kenneth Czerwinski

Second Committee Member

Daniel Koury

Third Committee Member

Frederic Poineau

Fourth Committee Member

Thomas Hartmann

Number of Pages

213

Abstract

Nuclear materials in the form of metals, oxides, halides, and other simple systems have a wide range of applications, from fuel for nuclear reactors, targets for medical isotopes production, and defense applications. The most common nuclear materials are the oxides, with actinide dioxides (i.e., PuO2, UO2, NpO2) being found in reactor fuels. Of importance for oxide materials is their dissolution into mineral acids (e.g., HNO3, HCl, HF), synthesis to other forms of nuclear materials (metals, halides), and the separation of uranium from plutonium after power generation. Commonly, the dissolution and synthesis of nuclear materials and surrogate material have been well documented, but new solvent systems (deep eutectic solvents) have not been thoroughly investigated.

The conversion of oxide to halide material has been documented using multiple halogenation agents. Of note, limited research has been performed detailing the reactions of aluminum halides (AlX3, X= Cl, Br, I) with CeO2. The synthesis conditions have not been reported in depth and when available do not meet modern standards of replication. The reaction of aluminum halides with UO2 has shown the ability to synthesize and volatilize uranium halides (X=Cl, Br, I) at low temperatures. This method, assisted by chemical vapor transport (CVT), is shown within to separate uranium from plutonium and surrogate materials (cerium) due to the limited volatility of plutonium and cerium halides compared to uranium halides.

One fundamental question in actinide chemistry is the existence of PuCl4 in the solid-state. While UCl4 has been none for centuries, PuCl4 has been only observed in the gas phase but never in the solid-state (either as PuCl4 or Pu1-xUxCl4 solid-solution). The preparation and study of Pu1- xUxCl4 or Ce1-xUxCl4 solid-solution will represent a crucial milestone toward PuCl4.

Presented here is the synthesis of cerium doped uranium chloride materials (via CCl4), synthesis of CeX3 materials using aluminum halides, and the separation of uranium from plutonium and cerium doped UO2 via CVT assisted by AlX3. This method has shown the ability to synthesize cerium doped UCl4 and separate uranium from cerium and plutonium doped UO2 with high efficiency for large burnup. Finally, the dissolution and oxidation of neptunium materials using a deep eutectic solvent (DES) of choline chloride and para-toluene sulfonic acid monohydrate is reported. These dissolutions were performed using environmentally friendly dissolution techniques.

Controlled Subject

Nuclear engineering--Materials; Oxides; Dissolution (Chemistry)

Disciplines

Chemistry | Materials Chemistry | Physical Sciences and Mathematics

File Format

PDF

File Size

3900 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Available for download on Saturday, May 15, 2027


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