Capability of the RELAP5 code to simulate natural circulation behavior in test facilities

► RELAP5/Mod3.2 has been used for simulation of natural circulation test facilities. ► Predictions are made for single-phase and two-phase natural circulation. ► Test data from a single channel and multichannel facility are used for comparison. ► Effect of nodalisation on predictions for steady state and stability is studied. ► The errors associated with predictions are characterized.