The material that sustains the nuclear reactions that produce energy can also be used to make nuclear weapons-and therefore, the development of nuclear energy is one of multiple pathways to proliferation for a non-nuclear weapon state. There is a tension between the development of future nuclear fuel cycles and managing the risk of proliferation as the number of existing and future nuclear energy systems expands throughout the world. As the Department of Energy (DOE) and other parts of the government make decisions about future nuclear fuel cycles, DOE would like to improve proliferation assessments to better inform those decisions. Improving the Assessment of the Proliferation Risk of Nuclear Fuel Cycles considers how the current methods of quantification of proliferation risk are being used and implemented, how other approaches to risk assessment can contribute to improving the utility of assessments for policy and decision makers. The study also seeks to understand the extent to which technical analysis of proliferation risk could be improved for policy makers through research and development.