Development of a sub-channel code for liquid metal cooled fuel assembly

Extensive study has been carried out for liquid metal cooled reactors (LMR). One of the challenges for the design of LMR is to keep the cladding temperature below the design limit. Thus, accurate prediction of coolant and fuel cladding temperature is highly required. In this study, a sub-channel analysis code COBRA-LM is developed for thermal-hydraulic analysis of liquid metal reactor. Based on COBRA-IV code, the development work of COBRA-LM can be divided into two steps. Firstly, Sodium and Lead-Bismuth properties calculation is introduced; secondly, pressure drop models, turbulent mixing models and heat transfer correlations are investigated and implemented into the code. Furthermore, verification and validation study of the new developed COBRA-LM code is performed. The ORNL-19 pin tests are chosen to assess the code's capability. Comparisons are performed to demonstrate the accuracy of the code by the results of CFX, MATRA-LMR and ORNL-19 test data. According to the results, it can be concluded that a reliable tool for sub-channel analysis of LMR is developed, model recommendation is also given for future study. Finally, an analysis for PHENIX reactor is simulated by COBRA-LM code.