Award Date

8-1-2014

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

First Committee Member

Kenneth R. Czerwinski

Second Committee Member

Gordon Jarvinen

Third Committee Member

Patricia Paviet-Hartmann

Fourth Committee Member

Ralf Sudowe

Number of Pages

185

Abstract

Several countries are currently expanding the use of nuclear energy as a method for the safe generation of carbon free energy and a number are evaluating starting up a nuclear power program. Closed fuel cycle technologies may be key to waste reduction and a sustainable nuclear energy future and to support the development of more efficient fuel cycles, the investigation of the chemical properties of key actinides is at the forefront of separations research. In this work the characterization of higher oxidation states of americium (Am) has been performed using spectroscopic methods. Americium in the formal oxidation state of Am(V) has been prepared by oxidation of Am(III) to Am(VI) in acid solution using sodium bismuthate (NaBiO3) followed by reduction of Am(VI) to Am(V). The oxidation state and stereochemical arrangements of atoms in close proximity to Am have been determined by x-ray absorption fine structure spectroscopy (XAFS), consisting of EXAFS (extended x-ray absorption fine structure spectroscopy) and XANES (x-ray absorption near-edge spectroscopy) analysis. Density Functional Theory (DFT) was used to create a model of Am(V) and Am(VI) using the data from these studies. Future work should focus on using this knowledge of Am higher oxidation states to design new more selective extraction processes for the separation of Am from curium (Cm) as well as lanthanide fission products from actinides in used nuclear fuel reprocessing and recycling.

Keywords

Actinide elements – Oxidation; Actinide elements – Separation; Americium; Curium; DFT; Nuclear energy; Nuclear fuel elements; Nuclear fuels; Oxidation; Sodium bismuthate; XAFS

Disciplines

Chemistry | Oil, Gas, and Energy | Radiochemistry

Language

English


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