Magnetohydrodynamic stabilizer suppressing gas entrainment for safety improvement in a sodium-cooled fast reactor

In a low-carbon economy, nuclear energy is considered a viable option to meet increased energy demands. Several countries have been developing sodium-cooled fast reactors (SFRs), which have a highest potential for commercialization among Generation IV reactor systems. However, for SFR's safe operation, the gas entrainment (GE) issue in SFRs should be resolved first. Although many types of free-surface stabilizers have been studied for preventing GE, any generalized types showing a stable operating performance have not been determined yet. In this study, as a new type of free-surface stabilizer, we have tested a magnetohydrodynamic (MHD) stabilizer for the Korean-conceptual SFR. A pair of torus-type magnets was devised for the MHD stabilizer through parametric-model studies. The magnetism well alleviated the sources of GE such as the rotating flow and central sink. As a result, a calm free surface was achieved with an 87% reduction in vortex core depth using 0.07 T magnetic field intensity.