Identification of postulated accident sequences in ITER

An essential part of the Engineering Design Activities (EDA) for the International Thermonuclear Experimental Reactor (ITER) is the assurance that the design meets strict safety criteria. Analyses have been performed of postulated accidents, in order that the possible consequences can be assessed against targets for releases and other criteria. The range of events considered is based on studies which use systematic techniques to provide a comprehensive identification of potential accident initiators and sequences. Two independent and complementary approaches have been employed, illustrated here by a portion of a global fault tree and a sample event tree. The result of these studies is a demonstration that the ITER accident analyses treat a comprehensive range of event sequences, and give confidence that the ITER engineering design will achieve its safety targets.