Suppression effect of Ti nanoparticles on sodium-water reaction

Abstract

The Sodium-Water Reaction (SWR) is a serious problem in Sodium-cooled Fast Reactor (SFR). When liquid sodium (Na) contacts water inside a heat exchanger, a strong chemical reaction occurs and increases the pressure of the system. To suppress this strong reaction during SWR, Na-based Titanium Nanofluid (NaTiNF), i.e., liquid Na that included dispersed Ti NPs (≤100 nm) has been suggested. Suppression of chemical reactivity in reaction between Na and water by NaTiNF was verified by measuring the hydrogen generation rates of the NaTiNF-water reaction and temperature increase of the NaTiNF-water vapor reaction. In NaTiNF-water reaction, NaTiNF showed the lower reaction than Na, but the suppression effect of NaTiNF became smaller as reaction temperature increased. From the visualization of NaTiNF-water vapor reaction, TI NPs on the Na surface affects the reaction rate. As the Ti NP concentration increased, reactivity of Na reduced. This indicated the Ti NPs on Na surface ruled the important factor in suppression of reactivity of SWR.