Application of the safety method of the lines of defence for two ITER accidents

A top–down safety evaluation for the International Thermonuclear Experimental Reactor (ITER) design has been performed through the application of the lines of defence (LODs) method for two basic reference accidents (divertor LOFA and LOCA). The results achieved in terms of LODs allotments for the two initiating events suggest two safety architectures for the ITER plant that are very similar. The results show also that the LODs method has good capability in optimising, with respect to different factors, the assignation of the LODs to the safety functions involved. By studying the elementary safety functions resulting from the functional analysis, interesting results concerning the needed reliability and performances of the ITER system/components have been found.