Introduction 1.1 Motivation 1.2 Objectives 1.3 Thesis Outline 1.4 Literature Review 1.4.1 Thermal Diffusion 1.4.2 Electromagnetic Separation 1.4.3 Gaseous Diffusion 1.4.4 Gas Centrifuges 1.4.5 Laser Enrichment Methods 1.4.6 Alternate Uses of Laser Enrichment 1.4.7 Nuclear Proliferation Concerns Related to Laser Enrichment CHAPTER 2. Background 2.1 Conventional Enrichment Technologies 2.1.1 Principles of Thermal Diffusion 2.1.2 Principles of Electromagnetic Separation 2.1.3 Principles of Gaseous Diffusion Enrichment 2.1.4 Principles of Gas Centrifuge Enrichment 2.2 Laser Enrichment Methods 2.2.1 Principles of AVLIS 2.2.2 Principles of MLIS CHAPTER 3. LIS Theory 3.1 LLNL and CEA: Difference in Nomenclature 3.1.1 Lawrence Livermore National Laboratory (LLNL): Nomenclature 3.1.2 French Alternative Energies and Atomic Energy Commission (CEA): Nomenclature 3.2 International LIS Development 3.3 Fundamental AVLIS Equations 3.4 Derived AVLIS Equations for Determining η and ϕ CHAPTER 4. Isotopic Ratios Resulting from Enrichment 4.1 Ratios from Gaseous Diffusion and Centrifuge Enrichment 4.1.1 Gaseous Diffusion v 4.1.2 Gas Centrifuge 4.2 Ratios from Laser Isotope Separation CHAPTER 5. Forensic Signatures From 234 U 5.1 Determining the Feedstock Origin 5.2 Determining Time of Last Enrichment CHAPTER 6. Conclusion 6.1 Conclusions 6.2 Recommendations REFERENCES vi LIST OF SYMBOLS AND ABBREVIATIONS