A New Integrated SSCs Safety Classification Method and a Case Study on CN HCCB TES

The Systems, Structures and Components (SSCs, also termed as items) in reactors have different safety significance for operation of the reactors and it is hence necessary to classify the SSCs into different safety classes for the design, manufacture and maintenance of the reactors. However, the 50-SG-D1 safety classification method was withdraw because the recommendations contained therein were considered to be not comply with the IAEA safety requirements (No. NS-R-1). In order to further identify the safety classes of the SSCs in the reactors, a new integrated safety classification method, based on the 50-SG-D1 safety classification method and risk-informed safety classification method, integrating relative importance and functions importance classification, is proposed in this study. To show the merits of the proposed method, this method is applied to analyze the China Helium Cooled Ceramic Breeder Tritium Extraction System (CN HCCB TES) in the International Thermonuclear Experimental Reactor (ITER). More comprehensive classification results were obtained by applying the proposed method, and the safety classification results indicate that safety classes of the items obtained by the proposed safety classification method are more significant than those derived from the present safety classification method.