Latest progress on the thermal-hydraulics research in lead-cooled fast reactors: A review

Lead-cooled fast reactors (LFR) stand out as a promising frontier in advanced nuclear reactor technology, boasting inherent safety features and efficient heat transfer. A comprehensive understanding of thermal-hydraulics is vital for reactor design and safety. This paper reviews thermal-hydraulics research in LFR, categorized into operation and accident conditions, presenting current research status, gaps, and future directions. During routine reactor operation within designed safety limits, the research emphasizes steady-state flow and heat transfer in the fuel bundle, flow-induced vibration, and natural circulation performance. In contrast, in accidents that potentially surpass safety limits and result in radiation release, the research delves into severe scenarios such as flow blockage, steam generator tube rupture, and thermal stratification during scram. Despite significant progress, key challenges remain. Main research gaps include integrating multi-physical and multi-scale research for full-scale reactor applications, unifying accident severity assessment, and developing advanced sensors in harsh lead/LBE environments. Interdisciplinary collaboration, advanced modeling, experimental validation, and sensor development are essential to address these gaps effectively. Overall, this review provides a foundation for researchers and engineers to address critical challenges, supporting the development of LFR.