Host: The Japan Society of Mechanical Engineers
Name : The 30th International Conference on Nuclear Engineering (ICONE30)
Date : May 21, 2023 - May 26, 2023
In Korea, various reactor designs are under development from the power reactors, e.g., APR+ to the SMRs. Most of them include Passive Safety Systems (PSSs). As PSSs are included in various reactor designs, it becomes crucial to assess the reliability of PSSs appropriately as a part of the Probabilistic Safety Assessment (PSA) of those reactors. There are three elements to be considered for the PSA of PSSs: (1) active components, (2) passive components, and (3) performance of PSSs. In the PSAs for the reactor designs under development in Korea, up to now, passive-related issues of PSSs, such as passive components and performance, are not modeled since we assume that their failure probabilities during the mission time are negligible. Therefore, only failures of active components are modeled in those PSAs. However, there are concerns about the performances of PSSs due to weak driving forces such as gravity. To assess the performances of PSSs, we use the thermalhydraulic reliability assessment (THRA) method. However, in using the THRA method, we need to resolve issues such as substantial computation loads, etc. In this paper, we summarize issues related to the reliability assessment of PSSs and introduce some research to resolve some of them.
