Liquid sodium to be described by sodium here after with suspended nanoparticles is expected to mitigate sodium-water reaction, because sodium with suspended nanoparticles will suppress the degree of chemical activity by the atomic interaction between nanoparticles and sodium. In order to investigate this interaction from the view point of physical property, we tried to measure the surface tension of sodium with suspended nanoparticles in a static and dynamic state.
For the measurement of the surface tension in a static state, we employed the pendant drop method. The measurements were done in the globe box keeping inert gas atmosphere, which was required for the experiment using sodium to get rid of an easy chemical reaction of sodium with oxygen and moisture. We succeeded to make pendant drops of sodium and sodium with suspended nanoparticles between 200°C and 500°C.
On the other hand, to evaluate the surface tension in a dynamic state, we employed the method applying the principle of the Kelvin-Helmholtz instability. The measurements were done in the globe box used in the static experiment. Sodium or sodium with suspended nanoparticles throwing a nozzle was ejected into a paraffin pool. Its fragments were made due to the Kelvin-Helmholtz instability. The fragments were retrieved from a paraffin pool and we measured fragment size distribution. We carried out the experiments at temperature of 150°C and 200°C, and the ejection volume rate of 3.0L/min and 6.0L/min.
It was found that droplet sizes of sodium with suspended nanoparticles were increased as compared with those of sodium without nanoparticles. This result physically must have mean that sodium with suspended nanoparticles has larger surface tension than that of sodium without nanoparticles in the present condition. Therefore, we could consider the effect of the atomic interaction might mitigate sodium-water reaction.