ADVANTAGES OF DIRECT COUPLING OF DYNAMIC PRA AND PHYSICAL SECURITY SIMULATION, ADDING OPERATOR ACTIONS AND RISK METHODOLOGIES

Security plans at commercial power plants are designed to ensure that adversaries cannot reach specific targets during an attack. Ensuring these targets are not reached provides very high assurance that the core is not damaged, and radiation is not released to the environment. The security systems, including personnel, to provide this assurance have driven security at commercial power plants to the point that it is the single largest recurring OPEX cost annually at many facilities. However, the fact that the attackers reached specific targets does not necessarily mean that core damage or a radioactive release will occur. Plant operators can stabilize and control the plant to protect it despite the adversaries' efforts, if the operators can safely execute specific procedures to restore the plant to a safe condition. A robust mechanism does not exist to determine if operators can effectively take appropriate actions to stabilize the plant. Because the plant state, including the attack and responses, is highly dynamic, an analysis must evaluate a range of dynamic conditions to provide the necessary assurance that operators can establish control and safely operate the plant in a reasonable time during an attack. Without the capability to evaluate the probability of success of operator actions preventing a release to the environment, facilities will have to continue providing a much higher level of security to ensure the attackers do not reach locations that could damage the core or release radiation. A tool to measure these actions' effectiveness, even during an ongoing attack, could give the assurance necessary to allow the plant operators and regulators to take 'credit' for these actions. Also, it ties the operations and security aspects of the plant together, allowing a much better understanding of what steps will be required, how security will have to interact with operations to ensure the safety of the operators executing these measures, and allow for planning and training exercises to implement these new capabilities effectively. This paper discusses the design of such a modeling and simulation tool that couples the Dynamic PRA with a physical security model that can be used to determine the effectiveness of operator actions during an attack to restore safe plant operation. This paper discusses a Dynamic PRA tool that can recommend operator actions, integrated with a physical security simulation tool that can model security and operator capabilities in the facility. The combination provides a wealth of quantitative data to evaluate the effectiveness of an operational strategy. Preliminary results from an actual tool integrating EMRALD and AVERT using Monte-Carlo simulation will be presented.