Post-72h procedures are special procedures for passive nuclear power plants. In order to evaluate the necessity and sufficiency of post-72 h procedures for passive nuclear power plants, and optimize and improve their weak links, this study analyzes the overall logic of the design basis and operating procedure system for passive nuclear power plants in demonstration projects. Based on the content and structure of the post-72 h procedures, this study proposes a general method for evaluating the necessity and sufficiency of the post-72 h procedures, the possible risk items in the process of procedure implementation are identified by using the logical block diagram of procedure implementation, and some optimization suggestions are put forward according to the rules of the demonstration project. The analysis results show that the post-72 h procedures are sufficient and necessary for the safe operation of passive nuclear power plants; their expressions are related to the procedure architecture; Clarifying the priority of procedure operation path and reducing procedure jump can improve the efficiency of procedure implementation. The relevant optimization suggestions can provide technical reference for the long-term safe operation of passive nuclear power plants after accidents. © 2022, Editorial Board of Journal of Nuclear Power Engineering. All right reserved.
