Study on the Law of Melting and Melt Migration of Single Fuel Plate

In order to grasp the evolution of plate fuel melting accidents and prevent the continuous melting and expansion of fuel, the fluid volume (VOF) method coupled with enthalpy-porous media method was used in a typical plate fuel research reactor JRR-3M to simulate the melting and melt migration of single fuel after the coolant channel was blocked. The simulation results show that the time period from the start to the end of molten material migration is no more than 6 seconds after the fuel plate melts; the migration process of the molten material will expand obviously in the transverse direction, and it will quickly migrate to the adjacent fuel plate along the vertical direction of the fuel plate, while it will stop at 25 mm ~ 30 mm from the central symmetry plane along the radial direction of the fuel plate, that is, the molten material will not penetrate the aluminum plate at the edge of the assembly. The research method provides a new solution for the analysis of plate-type fuel melting accidents and offers technical support for the safety demonstration of flow blockage accidents in plate-type fuel reactors.