A framework to estimate the coverage of AOPs in nuclear power plants

In this paper, a framework to estimate the coverage of AOPs in NPPs is proposed based on a SPV (Single Point Vulnerability) model. It is apparent that the sufficient coverage of AOPs is one of the prerequisites for improving the operational safety of NPPs because they provide a series of proper actions to be conducted by human operators, which are crucial for coping with off-normal conditions caused by the failure of critical components. In this light, the catalog of BEs (i.e., SPV components) identified from an SPV model could be a good source of information to enhance the coverage of AOPs. Unfortunately, because of the avalanche of the number of corresponding MCSs, it is inevitable to develop a screening process that allows us to select critical MCSs. For this reason, the MCSC score is defined along with the DIF concept. Based on the MCSC score, a framework that allows us to systematically investigate the coverage of AOPs is proposed in Ref. As a result, it is estimated that the coverage of AOPs being used in OPR1000 is about 63%. It should be noted that there are a couple of limitations in this study. For example, the precision of the abovementioned coverage entirely depends on that of the SPV model being scrutinized by the proposed framework. This implies that independent reviews of SMEs (Subject Matter Experts) who have sufficient knowledge on both the configuration and operation of NPPs are unavoidable to confirm the appropriateness of the suggested framework