<p>Recent advancements in reactor designs offer new capabilities, not seen before. To increase flexibility and reduce operation and maintenance costs, modern reactor designs (e.g., microreactors, SMRs) embrace new technologies which would allow revolutionary operational concepts such as remote monitoring and control, semiautonomous or near-autonomous operation, and two-way communications for real-time integration with the upcoming smart electric grid. Such a continuous data transmission from and towards a reactor site could introduce vulnerabilities and necessitates the prioritization of cybersecurity. However, classical IT-based encryption schemes have been shown to be vulnerable to cyberattacks, as they rely on computational complexity. It has been shown (e.g., Shor’s algorithm) that with the advent of quantum computing practically any asymmetric encryption could be broken within hours. To address this challenge, this thesis explores the feasibility of applying Quantum Key Distribution (QKD) to nuclear reactor communications. QKD is a physical-layer security scheme relying on the laws of quantum mechanics instead of mathematical complexity. QKD promises not only unconditional security but also detection of potential intrusion, as it allows the communication parties to become aware of eavesdropping. To test the proposed hypothesis, a novel simulation tool (NuQKD) was developed to allow for real-time simulation of the BB84 QKD protocol between two remote terminals. NuQKD offers new capabilities not currently available in other simulation tools including true random numbers, modeling of equipment imperfections, and modeling of fiber optic and free space quantum channels. NuQKD was rigorously benchmarked against analytical, numerical and experimental data. Then, a reference nuclear reactor scenario is proposed that is generic enough to cover various communications links internal and external to a reactor site. Using NuQKD, the internal and external data links of the nuclear reactor reference scenario were modeled, and the receiver operating characteristics (ROC) curves were calculated for various QKD configurations. It was found that that QKD can provide adequate key rates with low false alarm rates and has the potential of addressing nuclear industry’s high standards of confidentiality up to 100 km distance using fiber optic. As a result, QKD is shown to be compatible with the existing and future point-to-point reactor communication architectures. These results motivate further study of quantum communications for nuclear reactors.</p>

The safety performance of nuclear power reactors is a very important factor in evaluating nuclear energy sustainability. Improving the safety performance of nuclear reactors can enhance nuclear energy sustainability as it will improve the environmental indicator used to evaluate the overall sustainability of nuclear energy. Great interest is given now to advanced nuclear reactors especially those using passive safety components. Investigation of the improvement in nuclear safety using advanced reactors was done by comparing the safety performance of a conventional reactor which uses active safety systems, such as Pressurized Water Reactor (PWR), with an advanced reactor which uses passive safety systems, such as AP1000, during a design basis accident, such as Loss of Coolant Accident (LOCA), using the PCTran as a simulation code. To assess the safety performance of PWR and AP1000, the “Global Safety Index” GSI model was developed by introducing three indicators: probability of accident occurrence, performance of safety system in case of an accident occurrence, and the consequences of the accident. Only the second indicator was considered in this work. A more detailed model for studying the performance of passive safety systems in AP1000 was developed. That was done using SCDAPSIM/RELAP5 code as it is capable of modelling design basis accidents (DBAs) in advanced nuclear reactors.

<p>Modern reactors promise enhanced capabilities not previously possible including integration with the smart grid, remote monitoring, reduced operation and maintenance costs, and more efficient operation. . Modern reactors are designed for installation to remote areas and integration to the electric smart grid, which would require the need for secure undisturbed remote control and the implementation of two-way communications and advanced digital technologies. However, two-way communications between the reactor facility, the enterprise network and the grid would require continuous operation data transmission. This would necessitate a deep understanding of cybersecurity and the development of a robust cybersecurity management plan in all reactor communication networks. Currently, there is a limited number of testbeds, mostly virtual, to perform cybersecurity research and investigate and demonstrate cybersecurity implementations in a nuclear environment. To fill this gap, the goal of this thesis is the development of a real-time cyber-physical testbed with real operational and information technology data to allow for cybersecurity research in a representative nuclear environment. In this thesis, a prototypic cyber-physical testbed was designed, built, tested, and installed in PUR-1. The cyber-physical testbed consists of an Auxiliary Moderator Displacement Rod (AMDR) that experimentally simulates a regulating rod, several sensors, and digital controllers mirroring Purdue University Reactor One (PUR-1) operation. The cyber-physical testbed is monitored and controlled remotely from the Remote Monitoring and Simulation Station (RMSS), located in another building with no line of sight to the reactor room. The design, construction and testing of the cyber-physical testbed are presented along with its capabilities and limitations. The cyber-physical testbed network architecture enables the performance of simulated cyberattacks including false data injection and denial of service. Utilizing the RMSS setup, collected information from the cyber-physical testbed is compared with real-time operational PUR-1 data in order to evaluate system response under simulated cyber events. Furthermore, a physics-based model is developed and benchmarked to simulate physical phenomena in PUR-1 reactor pool and provide information about reactor parameters that cannot be collected from reactor instrumentation system.</p>