Abstract Bounding events are a range of events that encompass all the main potential hazards. Postulated initiating event-potential impacts table (PIE-PIT) studies were used for the selection of bounding events of International Thermonuclear Experimental Reactor (ITER) Test Blanket Module (TBM) system. Based on 20 PIEs obtained by Failure Mode and Effect Analysis (FMEA) and 10 plant states (PSs) identified using Master Logic Diagram (MLD), this paper describes the process of PIE-PIT studies on China Dual Functional Lithium Lead (DFLL) TBM system. A set of seven bounding events for the future accident analysis were sought-after. They characterize the main hazards associated with DFLL-TBM system.