Abstract The paper presents the assessment of RELAP5/SCDAP code capabilities to simulate the thermal–hydraulic behavior of liquid metal. The code has been recently modified to work with liquid metal; new heat transfer correlations have been implemented. As the code is widely used in our institute during the design process of the Chinese ADS reactor the assessment of the newly modified RELAP5/SCDAP is seen as a necessary step to ensure the quality of the code results. The present paper focuses on the simulation of the transients performed on the TALL facility. TALL has been constructed and operated at KTH Royal Institute of Technology of Stockholm. The full height facility was designed and operated to investigate the heat transfer performance of different heat exchangers and the thermal–hydraulic characteristics of natural and forced circulation flow under steady and transient conditions. Two different configurations are available for the TALL facility however only one is simulated for the present study with seven transients analyzed. Different LBE heat transfer correlations are compared for the calculations. A consistent and systematic approach for the nodalization development and assessment procedures that respond to the IAEA guidelines is discussed and thoroughly applied. The procedures and the database developed constitute the base in our institute for further study when more experimental data is made available.