The IAEA’s Nuclear Energy Series is organized in a hierarchical structure: Nuclear Energy Basic Principles, Objectives in four key areas, Guides on specific topics and Technical Reports with detailed technical information. This publication establishes the criteria that need to be fulfilled in the area of the nuclear fuel cycles in order to satisfy the Nuclear Energy Basic Principles for resources, fuel engineering and performance, spent fuel management and reprocessing, and research reactor nuclear fuel cycles.The publication is written for fuel vendors, owners and operators of nuclear facilities, research and development organizations, nuclear regulators and politicians.