This Safety Guide provides recommendations on meeting the requirements of IAEA Safety Standards Series No. SSR-2/1 (Rev. 1) relevant to reactor containment and associated systems. The publication addresses the containment structure and the systems with the functions of isolation, control and management of mass and energy releases, control and limitation of radioactive releases, and control and management of combustible gases. The Safety Guide is intended for use primarily for land based, stationary nuclear power plants with water cooled reactors designed for electricity generation or for other heat generating applications, such as for district heating or desalination.