Prepared as part of the IAEA programme on safety standards for nuclear power plants (NPPs), this Safety Guide deals with the provisions that should be made in the design of NPPs to protect site personnel, the public and the environment against radiological hazards in operational states, decommissioning and accident conditions, including severe accidents. It also provides recommendations for ensuring radiation protection in the design of new NPPs, design modifications to operating plants, and safety reviews of operating NPPs. Comprehensive annexes provide additional information on the subjects addressed in this Safety Guide.