Flow accelerated corrosion in nuclear power plants: a detailed review on mechanisms, mitigation, and management

Flow-Accelerated Corrosion (FAC) is one of the most critical degradation mechanisms in nuclear power plants (NPPs), particularly affecting carbon steel components exposed to high-temperature water and steam flows. This review provides a comprehensive overview of FAC mechanisms, highlighting the electrochemical and mass transfer processes responsible for oxide film dissolution and metal loss. Predictive modeling approaches, ranging from semi-empirical models to modern computational fluid dynamics (CFD) and machine learning (ML) techniques, are discussed in terms of their capability to forecast FAC progression under varied operational scenarios. Factors influencing the FAC rate of metals, including the environmental parameters and material composition, are discussed in detail. A detailed overview of experimental testing methods—including stirred autoclaves, jet impingement setups, and rotating cage systems—is provided, along with their limitations in replicating real-world reactor conditions. The paper also outlines the current mitigation strategies, including metal formulation, chemical inhibitors, and maintenance strategies for suitable operation in NPP. Recent advances highlight the role of alloying elements such as chromium (Cr) and molybdenum (Mo) in stabilizing protective oxide layers, while also revealing important limitations of CFD models (e.g., challenges in validation and surface kinetics integration) and ML methods (e.g., lack of interpretability and regulatory readiness). Future research directions emphasize the need for integrated, multi-physics models, real-time monitoring systems, and the development of advanced materials to ensure long-term structural integrity and safety in next-generation nuclear reactors.