Current status of digital twin architecture and application in nuclear energy field

Digital Twin (DT) technology has gained significant attention in various areas, including nuclear energy. Technologies such as machine learning, artificial intelligence, and high-fidelity modeling and simulation have been studied to further the digitalization of the nuclear industry. In this paper, an overview of the DT initiatives and developments for the design optimization and intelligent transformation of nuclear energy systems is described to provide a development trend of DT technology for nuclear reactors. For the design of DT for complex systems such as nuclear reactors, Model Based Systems Engineering (MBSE) technology offers requirements models, design processes, and system verification that are clearer, more precise, and more comprehensive. Four properties of Digital Twin for Nuclear Reactor System (DTNRS) are summarized, which are given by the block definition diagram of MBSE philosophy. Then, to bridge the gap between numerical models and theoretical research of DT, a systematic and hierarchical "V" architecture is proposed, which reflects the digital-related technologies of the DTNRS throughout the whole life cycle. Furthermore, a four-layered decomposition construction model is developed and a prospective application scenario of DTNRS is pictured. Finally, the five-step instructive demonstration of the DTNRS is given based on a Generation III (GEN-III) reactor with its visualized condition map.