Abstract: Based on the revised best-estimate code AHTLET-SC, a typical supercritical water cooled reactor (SCWR) system was modeled. Three non-LOCA accidents (loss of feed water heating, loss of turbine load without turbine bypass and reactor coolant pump seizure) were chosen to perform accident simulation and sensitivity analysis. Some important results e.g. core power, mass flow rate, the highest cladding temperature, and the highest fuel pellet centerline temperature were obtained. The results indicate that all parameters satisfy the safety criteria in the accidents mentioned above.