Study on chemical reactivity suppression and coolant applicability of sodium with suspended nanoparticles

Saito, Junichi ; Yoshioka, Naoki*; Nagai, Masahiko*; Ara, Kuniaki 

Liquid sodium is used as a coolant for fast breeder reactors because of its superior heat-transfer property, low neutron absorption property and wide liquid phase temperature region. The purpose of this study is to suppress the chemical reactivity of liquid sodium using nanotechnology. An atomic interaction between nanoparticle and sodium atom is applied to suppress the chemical reactivity of liquid sodium. The fundamental properties of surface tension and evaporation rate which relate to the reaction were changed by suspension of nanoparticles. By these changes the reaction heat and reaction rate with water or oxygen of sodium with suspended nanoparticles were suppressed. The thermal property and fluidity of sodium with suspended nanoparticles were same as sodium, because the nanoparticles in liquid sodium are quite small (nano-meter size) and small amount. From these results, it was found that the chemical reactivity was suppressed by suspension of nanoparticles, keeping the superior coolant properties of liquid sodium.