This publication deals with a general approach to the safe management of the operating lifetimes of nuclear power plants, which requires a continuing quest for excellence. It also responds to the concerns about maintaining adequate safety levels at ageing plants, even beyond their design lifetimes. Contents: 1. Introduction; 2. General safety objective; 3. Ageing processes; 4. Considerations related to design and construction; 5. Comparison with the design basis; 6. Review of the reference safety levels; 7. Safety reviews; 8. Infrastructure support for safe management of the operating lifetimes; 9. Management responsibilities.