Quantum Communications for Advanced Nuclear Reactors

The nuclear industry is embarking on a digital transformation with the advent of advanced reactor designs. Next-generation nuclear systems would have significant dependency on digital technologies and would employ cutting-edge instrumentation, to enable advanced functionalities such as remote monitoring and semi-autonomous operation. However, real-time sharing of process data and operational commands could introduce cyber vulnerabilities, which could be exploited by a potential adversary. While data privacy is typically secured through encryption, classical cryptography in use today relies on complicated mathematical functions, which could nevertheless be potentially compromised by advancements in the field of quantum computing. An alternative state-of-the-art method, promising unconditional security for remote communications, is Quantum Key Distribution (QKD). As a physical-layer security scheme, QKD leverages the laws of quantum physics instead of making any computational assumptions regarding adversarial capabilities.

This dissertation introduces a complete framework to analyze the integration of QKD with nuclear reactor communications, based on analytical, numerical, and experimental methods. A novel QKD simulation tool (NuQKD) is presented, offering modular design, advanced customization, and modeling precision. NuQKD is benchmarked against various experiments and is leveraged to conduct a parametric analysis on the limitations of practical QKD systems. A mathematical quantum-secured communication model is derived, defining the parameters, procedure, and boundary conditions to describe and evaluate the integration of a QKD system with a nuclear-grade digital controller. Data extracted from Purdue University's fully digital nuclear reactor (PUR-1) are analyzed to design remote operational use cases and reference communication scenarios, inspired by the networking features of advanced reactors. The developed use cases are evaluated in terms of secret key generation and eavesdropping detection through NuQKD simulations.

Finally, an end-to-end experimental demonstration of QKD under prototypic conditions in a nuclear power reactor is presented. By coupling PUR-1 with a QKD system, the complete secure data exchange procedure was evaluated in real time, under multiple parameter combinations, varying distances, and encryption protocols. The unified system achieved real-time, zero-delay, unconditionally secure encryption and decryption at distances up to 85 km for 2,000 transmitted signals and up to 135 km for a core of 68 signals. Additionally, experiment results highlighted the ability to ensure up to several hours of secure key availability during potential system downtime. The overall analysis demonstrates the potential of quantum-based secure remote communications for future, digitally driven, nuclear reactor technologies.