Concerns over the proliferation and instances of nuclear material in the environment have increased interest in the expansion of nuclear forensics analysis and attribution programs. A new related field, molecular forensic science (MFS) has helped meet this expansion by applying common scientific analyses to nuclear forensics scenarios. In this work, MFS was applied to three scenarios related to nuclear forensics analysis. In the first, uranium dioxide was synthesized and aged at four sets of static environmental conditions and studied for changes in chemical speciation. The second highlighted the importance of bulk versus particle characterizations by analyzing a heterogeneous industrially prepared sample with similar techniques. In the third, mixed uranium/plutonium hot particles were collected from the McGuire Air Force Base BOMARC Site and analyzed for chemical speciation and elemental surface composition. This work has identified new signatures and has indicated unexpected chemical behavior under various conditions. These findings have lead to an expansion of basic actinide understanding, proof of MFS as a tool for nuclear forensic science, and new areas for expansion in these fields. v At each step in my life, I have considered myself lucky. I have worked hard, but the credit should go to my friends and family. Without their help, love, and support, I would not have completed this journey. I came from small beginnings, but with the support my parents, Dave and Lisa Reilly; I have come this far and will continue to honor them, my many friends, colleagues, and mentors by continuing to further myself as a scientist and person. vi TABLE OF CONTENTS ABSTRACT .