In 2018, the National Academies of Sciences, Engineering, and Medicine issued an Interim Report evaluating the general viability of the U.S. Department of Energy's National Nuclear Security Administration's (DOE-NNSA's) conceptual plans for disposing of 34 metric tons (MT) of surplus plutonium in the Waste Isolation Pilot Plant (WIPP), a deep geologic repository near Carlsbad, New Mexico. It provided a preliminary assessment of the general viability of DOE-NNSA's conceptual plans, focused on some of the barriers to their implementation. This final report addresses the remaining issues and echoes the recommendations from the interim study.

The production of nuclear materials for the national defense was an intense, nationwide effort that began with the Manhattan Project and continued throughout the Cold War. Now many of these product materials, by-products, and precursors, such as irradiated nuclear fuels and targets, have been declared as excess by the Department of Energy (DOE). Most of this excess inventory has been, or will be, turned over to DOE's Office of Environmental Management (EM), which is responsible for cleaning up the former production sites. Recognizing the scientific and technical challenges facing EM, Congress in 1995 established the EM Science Program (EMSP) to develop and fund directed, long-term research that could substantially enhance the knowledge base available for new cleanup technologies and decision making. The EMSP has previously asked the National Academies' National Research Council for advice for developing research agendas in subsurface contamination, facility deactivation and decommissioning, high-level waste, and mixed and transuranic waste. For this study the committee was tasked to provide recommendations for a research agenda to improve the scientific basis for DOE's management of its high-cost, high-volume, or high-risk excess nuclear materials and spent nuclear fuels. To address its task, the committee focused its attention on DOE's excess plutonium-239, spent nuclear fuels, cesium-137 and strontium-90 capsules, depleted uranium, and higher actinide isotopes.

Global energy demands are driving a potential expansion in the use of nuclear energy worldwide. It is estimated that the global nuclear power capacity could double by 2030. This could result in dissemination of sensitive nuclear technologies that present obvious risks of proliferation. Certain international institutional mechanisms for controlling access to sensitive materials, facilities and technologies are needed for dealing with this problem. Over the past few years, 12 proposals have been put forward by states, nuclear industry and international organizations, aimed at checking the spread of uranium enrichment and spent fuel reprocessing technologies. This book presents an overview and analysis of these proposals, including an evaluation of the projected international mechanisms.

Interest in nuclear energy continues to grow in many countries as a means to ensure security of energy supply and to limit greenhouse gas emissions from the power sector. In this context, recyclable materials constitute an asset for broadening the resource base for nuclear fuel supply, especially in medium- and long-term perspectives. This report provides an overview of recyclable fissile and fertile materials inventories which can be reused as nuclear fuel. It reviews the options available for managing those materials, through recycling and/or disposal. The potential energetic value of recyclable materials is assessed, taking into account the variability of retrievable energy contents of various materials according to technology and strategy choices made by the owners of the materials. The analyses contained in this report will be of particular interest to energy policy makers and to nuclear fuel cycle experts. Also available in this series: Innovation in Nuclear Energy Technology (2007) Forty Years of Uranium Resources, Production and Demand in Perspective: The Red Book Retrospective (2006) Nuclear Power Plant Life Management and Longer-term Operation (2006)