Abstract
To investigate the transient characteristic of the passive emergency feedwater system (PEFS), a small test facility is designed to do scaling simulation and support the code development. Scaling analysis was performed to find the criteria for the simulation study and the test facility design. The results show, natural circulation, single and two-phase heat transfer, and single and two-phase flow have important effect on the characteristic of the PEFS. Based on the scaling analysis, a small scale test facility was designed to carry out the static and transient investigation.