The design and operational requirements of nuclear facilities, such as nuclear power plants (NPPs), are specified and managed to ensure the safety and optimized operation of the facility. These requirements and how they are managed, interpreted and used to support facility functions and activities, are very important in all the life cycle phases of the facility from design through construction, commissioning, operation, and from refurbishment to decommissioning. This publication analyses and provides new insights into the different approaches followed by the nuclear industry for their effective management as well as guidance to develop a comprehensive requirement management programme in nuclear facilities. Although the guidance provided is based on industry experience to develop such programmes for NPPs, the principles and approaches provided can be used in all nuclear facilities including research reactors, fuel manufacturing facilities, fuel reprocessing and waste management facilities.