The multiphase flow phenomenon of the interaction between lead-bismuth eutectic and water is a safety concern for the design of lead-based fast reactor. In order to investigate the steam transport characteristics under a postulated Steam Generator Tube Rupture (SGTR) accident in a lead-based reactor, numerical simulation of lead-bismuth eutectic-water/steam multiphase flow in a reactor pool was performed and the effects of failure location and pressure of secondary loop on steam volume fraction in reactor core was evaluated. Under the present theoretical analysis, the results showed that the maximum steam volume fraction in the core occurred for the condition of cooling tube failure located at the outlet of SG which is closest to the pump duct and the accident consequence might be the most serious. The maximum steam volume fraction in reactor core increased with the increasing of the pressure of secondary loop. The analysis results will provide reference for the safety design and engineering guidance of lead-cooled fast reactor. (C) 2019 Elsevier Ltd. All rights reserved.