Molten Fuel Propagation in Sodium-Filled Fast Reactor Subassembly Geometries

In the Sodium Entry Series (SES) experiments carried out at the Winfrith Technology Centre’s Molten Fuel Test Facility, thermite-generated, molten uranium dioxide is injected into test sections that represent fullscale typical geometries of a fast reactor subassembly. The test sections are initially full of sodium at 500°C. Comparisons with previous studies without sodium show that the molten material progressed for similar distances before freezing. In addition, there is a complete absence of molten fuel/coolant interactions in all the SES experiments. Consequently, it is concluded that the presence of sodium has little influence on the propagation of molten fuel through initially intact subassembly geometries.