The United States has deployed commercial nuclear power since the 1950s, and as of 2021, nuclear power accounts for approximately 20 percent of U.S. electricity generation. The current commercial nuclear fleet consists entirely of thermal-spectrum, light water reactors operating with low-enriched uranium dioxide fuel in a once-through fuel cycle. In recent years, the U.S. Congress, U.S. Department of Energy, and private sector have expressed considerable interest in developing and deploying advanced nuclear reactors to augment, and possibly replace, the U.S. operating fleet of reactors, nearly all of which will reach the end of their currently licensed operating lives by 2050. Much of this interest stems from the potential ability of advanced reactors and their associated fuel cycles - as claimed by their designers and developers - to provide a number of advantages, such as improvements in economic competitiveness, reductions in environmental impact via better natural resource utilization and/or lower waste generation, and enhancements in nuclear safety and proliferation resistance.

At the request of Congress, this report explores merits and viability of different nuclear fuel cycles, including fuel cycles that may use reprocessing, for both existing and advanced reactor technologies; and waste management (including transportation, storage, and disposal options) for advanced reactors, and in particular, the potential impact of advanced reactors and their fuel cycles on waste generation and disposal.

Table of Contents

Front Matter Executive Summary Summary 1 Background and Study Task 2 Merits and Viability of Existing Nuclear Fuel Cycles for U.S. Light Water Reactors 3 Potential Merits and Viability of Advanced Nuclear Reactors and Associated Fuel Cycles 4 Fuel Cycle Development for Advanced Nuclear Reactors 5 Management and Disposal of Nuclear Waste from Advanced Reactors 6 Nonproliferation Implications and Security Risks References Appendix A: Biographical Sketches of the Committee and Project Staff Appendix B: Presentations at the Committee's Information-Gathering Meetings Appendix C: Acronyms and Abbreviations Appendix D: Radioactive Waste Classifications and Waste Characteristics from Different Stages of the Fuel Cycle in the United States Appendix E: Fuel Cycle Characteristics and Geologic Repository Metrics of Advanced Nuclear Reactors Appendix F: Sample List of National Academies Reports on Nuclear Waste Management Appendix G: Reprocessing and Geologic Disposal of TRISO Fuel Appendix H: Reprocessing and Recycling Practices in Other Countries Appendix I: Statement of Task for Parallel National Academies' Study Laying the Foundation for New and Advanced Nuclear Reactors in the United States