The nuclear power plants (NPPs) in one site may share (cross-tie) structures, systems, and components (SSCs) either in normal operation or in demand. For instance, the sharing of electrical power source as a cross-tie of emergency diesel generators (EDGs) could add advantages to the reduction of the station blackout (SBO) frequency for the unit with extended SBO. At the same time, the cross-tie is associated with risks that can limit the shared systems from performing its intended functions. The cross-tie risks that introduced from sharing need to be addressed and managed systemically.
First, the research will start with the framework of the development of a methodology for risk analysis and management in sharing of electrical power in nuclear power plants. Second, we will investigate detailed identified issues of the electrical cross-tie in extended SBO event as a risk of dependency between multi-unit site. Third, we will elaborate the probabilistic risk assessment (PRA) in assessing the safety of the NPP with the examination of common cause failures (CCFs) impact on the PRA risk quantification as a case study. The methodology of quantifying the risk of sharing of electrical cross-tie is developed in this stage and will be modeled in different cases. Lastly, we conclude the risk management process to access the cross-tie risk of multi-unit in different accident scenarios of SBO. Related analysis such as sensitivity, importance measures, risk, and cost analysis will be utilized in supporting the risk-informed decision-making process in selecting between mitigation options and reducing the SBO risk.
