SAFETY P R A C TIC E S - gnssn - International Atomic Energy Agency

This publication is no longer validPlease see http://www-ns.iaea.org/standards/(7) Is the design such that no single protective relay or interlock failure willprevent disconnection of the normal power supply when it fails?(8) Is the design of the normal power supply connection circuit and its controlssuch as to preclude the automatic reconnection of the normal power supply tothe respective division of the EPS when it is being powered from its stand-bypower supply?(9) On failure of the normal power supply does the design provide for the automaticdisconnection of the normal power supply and the startup and connectionof the stapd-by power supply to the appropriate division of the EPS within thespecified time?3.2.4. Protection against natural phenomenaThe design basis for the plant will detail the natural phenomena which haveto be taken into account in the design of the EPS.Basis of acceptanceCode, paras 314, A205, A206.Assessment questions(1) Are all structures, systems and components of the EPS designed and qualifiedto remain functional following an earthquake of level SL2?4(2) Are buildings, enclosures supports and anchors for the components and equipmentof the EPS designed to remain functional following an earthquake of levelSL2?(3) Are the components and equipment for the EPS physically separated or otherwiseprotected from structures, systems and components which are notdesigned to remain functional or maintain their structural integrity followingan earthquake of level SL2?(4) Are the components and equipment for the EPS housed and/or otherwiseprotected so as to remain functional against the direct and consequential effects(including the failure of unqualified equipment and structures) of tornados,hurricanes, tsunami and seiches, i.e. high winds, missiles, floods, etc., asapplicable?4 For definition see Safety Guide 50-SG-S1. The level SL2 is often also called thesafe shutdown earthquake.12