This Safety Guide has been developed through a series of technical meetings and represents an international consensus on useful design principles. These principles incorporate features which will be effective in maintaining fuel subcritical, removing residual heat, providing radiation protection and containing radioactive materials for the lifetime of the facility. It is intended for use by the nuclear power industry, its supporting organizations and related regulatory bodies in identifying and managing all relevant issues on the design aspects for the safe interim storage of spent fuel from nuclear power plants. It complements Safety Series No. 117, Operation of Spent Fuel Storage, and Safety Series No. 118, Safety Assessment for Spent Fuel Storage Facilities. (Please note: this publication is superseded by SSG-15)