Application of direct passive residual heat removal system to the SMART reactor

• An applicability study of the DRHRS to the SMART reactor was conducted.
• Evaluations were performed for a station blackout scenario.
• The adoption of the DRHRS in the SMART reactor was found feasible.

A feasibility study on the application of the DRHRS to the SMART reactor was performed, using the MARS code. As a limiting event for the evaluation, an SBO event was used. From the MARS analysis on the DRHRS evaluation, most of the thermal hydraulic behaviors showed reasonable trends in pressure, temperature, and water levels. During the simulation, it was found out that mass transfer takes place between regions in the reactor vessel, especially from 2500 s to 11,000 s. Most of the mass transfer occurred from the outer regions in the reactor vessel, e.g., RV-outer1 and RV-outer2 regions, to the RV-inner region. The cooling flowrate in the CHX of the DRHRS was maintained between 7 and 8 kg/s for the simulation time. From this feasibility study, it can be concluded that the adoption of the DRHRS to the SMART reactor is reasonable at least from the view point of an SBO event.